thread.cpp revision 342:37f87013dfd8
1/* 2 * Copyright 1997-2007 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 32HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 33HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 34HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 35 intptr_t, intptr_t, bool); 36HS_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 69void* 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 90void 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 104Thread::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 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;) 131 _highest_lock = NULL; 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 184void 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 201void 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 207Thread::~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. 246void Thread::run() { 247 ShouldNotReachHere(); 248} 249 250#ifdef ASSERT 251// Private method to check for dangling thread pointer 252void 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 261void 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 292ThreadPriority 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 301void 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 309void 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 327void 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 368class 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 416bool 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// 541bool 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 625void 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: 643bool 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 653void Thread::interrupt(Thread* thread) { 654 trace("interrupt", thread); 655 debug_only(check_for_dangling_thread_pointer(thread);) 656 os::interrupt(thread); 657} 658 659bool 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 669bool 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 686void Thread::oops_do(OopClosure* f) { 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 693void Thread::nmethods_do() { 694} 695 696void Thread::print_on(outputStream* st) const { 697 // get_priority assumes osthread initialized 698 if (osthread() != NULL) { 699 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this); 700 osthread()->print_on(st); 701 } 702 debug_only(if (WizardMode) print_owned_locks_on(st);) 703} 704 705// Thread::print_on_error() is called by fatal error handler. Don't use 706// any lock or allocate memory. 707void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 708 if (is_VM_thread()) st->print("VMThread"); 709 else if (is_Compiler_thread()) st->print("CompilerThread"); 710 else if (is_Java_thread()) st->print("JavaThread"); 711 else if (is_GC_task_thread()) st->print("GCTaskThread"); 712 else if (is_Watcher_thread()) st->print("WatcherThread"); 713 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 714 else st->print("Thread"); 715 716 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 717 _stack_base - _stack_size, _stack_base); 718 719 if (osthread()) { 720 st->print(" [id=%d]", osthread()->thread_id()); 721 } 722} 723 724#ifdef ASSERT 725void Thread::print_owned_locks_on(outputStream* st) const { 726 Monitor *cur = _owned_locks; 727 if (cur == NULL) { 728 st->print(" (no locks) "); 729 } else { 730 st->print_cr(" Locks owned:"); 731 while(cur) { 732 cur->print_on(st); 733 cur = cur->next(); 734 } 735 } 736} 737 738static int ref_use_count = 0; 739 740bool Thread::owns_locks_but_compiled_lock() const { 741 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 742 if (cur != Compile_lock) return true; 743 } 744 return false; 745} 746 747 748#endif 749 750#ifndef PRODUCT 751 752// The flag: potential_vm_operation notifies if this particular safepoint state could potential 753// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 754// no threads which allow_vm_block's are held 755void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 756 // Check if current thread is allowed to block at a safepoint 757 if (!(_allow_safepoint_count == 0)) 758 fatal("Possible safepoint reached by thread that does not allow it"); 759 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 760 fatal("LEAF method calling lock?"); 761 } 762 763#ifdef ASSERT 764 if (potential_vm_operation && is_Java_thread() 765 && !Universe::is_bootstrapping()) { 766 // Make sure we do not hold any locks that the VM thread also uses. 767 // This could potentially lead to deadlocks 768 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 769 // Threads_lock is special, since the safepoint synchronization will not start before this is 770 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 771 // since it is used to transfer control between JavaThreads and the VMThread 772 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first! 773 if ( (cur->allow_vm_block() && 774 cur != Threads_lock && 775 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation 776 cur != VMOperationRequest_lock && 777 cur != VMOperationQueue_lock) || 778 cur->rank() == Mutex::special) { 779 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 780 } 781 } 782 } 783 784 if (GCALotAtAllSafepoints) { 785 // We could enter a safepoint here and thus have a gc 786 InterfaceSupport::check_gc_alot(); 787 } 788 789#endif 790} 791#endif 792 793bool Thread::lock_is_in_stack(address adr) const { 794 assert(Thread::current() == this, "lock_is_in_stack can only be called from current thread"); 795 // High limit: highest_lock is set during thread execution 796 // Low limit: address of the local variable dummy, rounded to 4K boundary. 797 // (The rounding helps finding threads in unsafe mode, even if the particular stack 798 // frame has been popped already. Correct as long as stacks are at least 4K long and aligned.) 799 address end = os::current_stack_pointer(); 800 if (_highest_lock >= adr && adr >= end) return true; 801 802 return false; 803} 804 805 806bool Thread::is_in_stack(address adr) const { 807 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 808 address end = os::current_stack_pointer(); 809 if (stack_base() >= adr && adr >= end) return true; 810 811 return false; 812} 813 814 815// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 816// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 817// used for compilation in the future. If that change is made, the need for these methods 818// should be revisited, and they should be removed if possible. 819 820bool Thread::is_lock_owned(address adr) const { 821 if (lock_is_in_stack(adr) ) return true; 822 return false; 823} 824 825bool Thread::set_as_starting_thread() { 826 // NOTE: this must be called inside the main thread. 827 return os::create_main_thread((JavaThread*)this); 828} 829 830static void initialize_class(symbolHandle class_name, TRAPS) { 831 klassOop klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 832 instanceKlass::cast(klass)->initialize(CHECK); 833} 834 835 836// Creates the initial ThreadGroup 837static Handle create_initial_thread_group(TRAPS) { 838 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK_NH); 839 instanceKlassHandle klass (THREAD, k); 840 841 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 842 { 843 JavaValue result(T_VOID); 844 JavaCalls::call_special(&result, 845 system_instance, 846 klass, 847 vmSymbolHandles::object_initializer_name(), 848 vmSymbolHandles::void_method_signature(), 849 CHECK_NH); 850 } 851 Universe::set_system_thread_group(system_instance()); 852 853 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 854 { 855 JavaValue result(T_VOID); 856 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 857 JavaCalls::call_special(&result, 858 main_instance, 859 klass, 860 vmSymbolHandles::object_initializer_name(), 861 vmSymbolHandles::threadgroup_string_void_signature(), 862 system_instance, 863 string, 864 CHECK_NH); 865 } 866 return main_instance; 867} 868 869// Creates the initial Thread 870static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 871 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK_NULL); 872 instanceKlassHandle klass (THREAD, k); 873 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 874 875 java_lang_Thread::set_thread(thread_oop(), thread); 876 java_lang_Thread::set_priority(thread_oop(), NormPriority); 877 thread->set_threadObj(thread_oop()); 878 879 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 880 881 JavaValue result(T_VOID); 882 JavaCalls::call_special(&result, thread_oop, 883 klass, 884 vmSymbolHandles::object_initializer_name(), 885 vmSymbolHandles::threadgroup_string_void_signature(), 886 thread_group, 887 string, 888 CHECK_NULL); 889 return thread_oop(); 890} 891 892static void call_initializeSystemClass(TRAPS) { 893 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK); 894 instanceKlassHandle klass (THREAD, k); 895 896 JavaValue result(T_VOID); 897 JavaCalls::call_static(&result, klass, vmSymbolHandles::initializeSystemClass_name(), 898 vmSymbolHandles::void_method_signature(), CHECK); 899} 900 901static void reset_vm_info_property(TRAPS) { 902 // the vm info string 903 ResourceMark rm(THREAD); 904 const char *vm_info = VM_Version::vm_info_string(); 905 906 // java.lang.System class 907 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK); 908 instanceKlassHandle klass (THREAD, k); 909 910 // setProperty arguments 911 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 912 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 913 914 // return value 915 JavaValue r(T_OBJECT); 916 917 // public static String setProperty(String key, String value); 918 JavaCalls::call_static(&r, 919 klass, 920 vmSymbolHandles::setProperty_name(), 921 vmSymbolHandles::string_string_string_signature(), 922 key_str, 923 value_str, 924 CHECK); 925} 926 927 928void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 929 assert(thread_group.not_null(), "thread group should be specified"); 930 assert(threadObj() == NULL, "should only create Java thread object once"); 931 932 klassOop k = SystemDictionary::resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK); 933 instanceKlassHandle klass (THREAD, k); 934 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 935 936 java_lang_Thread::set_thread(thread_oop(), this); 937 java_lang_Thread::set_priority(thread_oop(), NormPriority); 938 set_threadObj(thread_oop()); 939 940 JavaValue result(T_VOID); 941 if (thread_name != NULL) { 942 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 943 // Thread gets assigned specified name and null target 944 JavaCalls::call_special(&result, 945 thread_oop, 946 klass, 947 vmSymbolHandles::object_initializer_name(), 948 vmSymbolHandles::threadgroup_string_void_signature(), 949 thread_group, // Argument 1 950 name, // Argument 2 951 THREAD); 952 } else { 953 // Thread gets assigned name "Thread-nnn" and null target 954 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 955 JavaCalls::call_special(&result, 956 thread_oop, 957 klass, 958 vmSymbolHandles::object_initializer_name(), 959 vmSymbolHandles::threadgroup_runnable_void_signature(), 960 thread_group, // Argument 1 961 Handle(), // Argument 2 962 THREAD); 963 } 964 965 966 if (daemon) { 967 java_lang_Thread::set_daemon(thread_oop()); 968 } 969 970 if (HAS_PENDING_EXCEPTION) { 971 return; 972 } 973 974 KlassHandle group(this, SystemDictionary::threadGroup_klass()); 975 Handle threadObj(this, this->threadObj()); 976 977 JavaCalls::call_special(&result, 978 thread_group, 979 group, 980 vmSymbolHandles::add_method_name(), 981 vmSymbolHandles::thread_void_signature(), 982 threadObj, // Arg 1 983 THREAD); 984 985 986} 987 988// NamedThread -- non-JavaThread subclasses with multiple 989// uniquely named instances should derive from this. 990NamedThread::NamedThread() : Thread() { 991 _name = NULL; 992} 993 994NamedThread::~NamedThread() { 995 if (_name != NULL) { 996 FREE_C_HEAP_ARRAY(char, _name); 997 _name = NULL; 998 } 999} 1000 1001void NamedThread::set_name(const char* format, ...) { 1002 guarantee(_name == NULL, "Only get to set name once."); 1003 _name = NEW_C_HEAP_ARRAY(char, max_name_len); 1004 guarantee(_name != NULL, "alloc failure"); 1005 va_list ap; 1006 va_start(ap, format); 1007 jio_vsnprintf(_name, max_name_len, format, ap); 1008 va_end(ap); 1009} 1010 1011// ======= WatcherThread ======== 1012 1013// The watcher thread exists to simulate timer interrupts. It should 1014// be replaced by an abstraction over whatever native support for 1015// timer interrupts exists on the platform. 1016 1017WatcherThread* WatcherThread::_watcher_thread = NULL; 1018bool WatcherThread::_should_terminate = false; 1019 1020WatcherThread::WatcherThread() : Thread() { 1021 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1022 if (os::create_thread(this, os::watcher_thread)) { 1023 _watcher_thread = this; 1024 1025 // Set the watcher thread to the highest OS priority which should not be 1026 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1027 // is created. The only normal thread using this priority is the reference 1028 // handler thread, which runs for very short intervals only. 1029 // If the VMThread's priority is not lower than the WatcherThread profiling 1030 // will be inaccurate. 1031 os::set_priority(this, MaxPriority); 1032 if (!DisableStartThread) { 1033 os::start_thread(this); 1034 } 1035 } 1036} 1037 1038void WatcherThread::run() { 1039 assert(this == watcher_thread(), "just checking"); 1040 1041 this->record_stack_base_and_size(); 1042 this->initialize_thread_local_storage(); 1043 this->set_active_handles(JNIHandleBlock::allocate_block()); 1044 while(!_should_terminate) { 1045 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1046 assert(watcher_thread() == this, "thread consistency check"); 1047 1048 // Calculate how long it'll be until the next PeriodicTask work 1049 // should be done, and sleep that amount of time. 1050 const size_t time_to_wait = PeriodicTask::time_to_wait(); 1051 os::sleep(this, time_to_wait, false); 1052 1053 if (is_error_reported()) { 1054 // A fatal error has happened, the error handler(VMError::report_and_die) 1055 // should abort JVM after creating an error log file. However in some 1056 // rare cases, the error handler itself might deadlock. Here we try to 1057 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1058 // 1059 // This code is in WatcherThread because WatcherThread wakes up 1060 // periodically so the fatal error handler doesn't need to do anything; 1061 // also because the WatcherThread is less likely to crash than other 1062 // threads. 1063 1064 for (;;) { 1065 if (!ShowMessageBoxOnError 1066 && (OnError == NULL || OnError[0] == '\0') 1067 && Arguments::abort_hook() == NULL) { 1068 os::sleep(this, 2 * 60 * 1000, false); 1069 fdStream err(defaultStream::output_fd()); 1070 err.print_raw_cr("# [ timer expired, abort... ]"); 1071 // skip atexit/vm_exit/vm_abort hooks 1072 os::die(); 1073 } 1074 1075 // Wake up 5 seconds later, the fatal handler may reset OnError or 1076 // ShowMessageBoxOnError when it is ready to abort. 1077 os::sleep(this, 5 * 1000, false); 1078 } 1079 } 1080 1081 PeriodicTask::real_time_tick(time_to_wait); 1082 1083 // If we have no more tasks left due to dynamic disenrollment, 1084 // shut down the thread since we don't currently support dynamic enrollment 1085 if (PeriodicTask::num_tasks() == 0) { 1086 _should_terminate = true; 1087 } 1088 } 1089 1090 // Signal that it is terminated 1091 { 1092 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1093 _watcher_thread = NULL; 1094 Terminator_lock->notify(); 1095 } 1096 1097 // Thread destructor usually does this.. 1098 ThreadLocalStorage::set_thread(NULL); 1099} 1100 1101void WatcherThread::start() { 1102 if (watcher_thread() == NULL) { 1103 _should_terminate = false; 1104 // Create the single instance of WatcherThread 1105 new WatcherThread(); 1106 } 1107} 1108 1109void WatcherThread::stop() { 1110 // it is ok to take late safepoints here, if needed 1111 MutexLocker mu(Terminator_lock); 1112 _should_terminate = true; 1113 while(watcher_thread() != NULL) { 1114 // This wait should make safepoint checks, wait without a timeout, 1115 // and wait as a suspend-equivalent condition. 1116 // 1117 // Note: If the FlatProfiler is running, then this thread is waiting 1118 // for the WatcherThread to terminate and the WatcherThread, via the 1119 // FlatProfiler task, is waiting for the external suspend request on 1120 // this thread to complete. wait_for_ext_suspend_completion() will 1121 // eventually timeout, but that takes time. Making this wait a 1122 // suspend-equivalent condition solves that timeout problem. 1123 // 1124 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1125 Mutex::_as_suspend_equivalent_flag); 1126 } 1127} 1128 1129void WatcherThread::print_on(outputStream* st) const { 1130 st->print("\"%s\" ", name()); 1131 Thread::print_on(st); 1132 st->cr(); 1133} 1134 1135// ======= JavaThread ======== 1136 1137// A JavaThread is a normal Java thread 1138 1139void JavaThread::initialize() { 1140 // Initialize fields 1141 1142 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1143 set_claimed_par_id(-1); 1144 1145 set_saved_exception_pc(NULL); 1146 set_threadObj(NULL); 1147 _anchor.clear(); 1148 set_entry_point(NULL); 1149 set_jni_functions(jni_functions()); 1150 set_callee_target(NULL); 1151 set_vm_result(NULL); 1152 set_vm_result_2(NULL); 1153 set_vframe_array_head(NULL); 1154 set_vframe_array_last(NULL); 1155 set_deferred_locals(NULL); 1156 set_deopt_mark(NULL); 1157 clear_must_deopt_id(); 1158 set_monitor_chunks(NULL); 1159 set_next(NULL); 1160 set_thread_state(_thread_new); 1161 _terminated = _not_terminated; 1162 _privileged_stack_top = NULL; 1163 _array_for_gc = NULL; 1164 _suspend_equivalent = false; 1165 _in_deopt_handler = 0; 1166 _doing_unsafe_access = false; 1167 _stack_guard_state = stack_guard_unused; 1168 _exception_oop = NULL; 1169 _exception_pc = 0; 1170 _exception_handler_pc = 0; 1171 _exception_stack_size = 0; 1172 _jvmti_thread_state= NULL; 1173 _jvmti_get_loaded_classes_closure = NULL; 1174 _interp_only_mode = 0; 1175 _special_runtime_exit_condition = _no_async_condition; 1176 _pending_async_exception = NULL; 1177 _is_compiling = false; 1178 _thread_stat = NULL; 1179 _thread_stat = new ThreadStatistics(); 1180 _blocked_on_compilation = false; 1181 _jni_active_critical = 0; 1182 _do_not_unlock_if_synchronized = false; 1183 _cached_monitor_info = NULL; 1184 _parker = Parker::Allocate(this) ; 1185 1186#ifndef PRODUCT 1187 _jmp_ring_index = 0; 1188 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1189 record_jump(NULL, NULL, NULL, 0); 1190 } 1191#endif /* PRODUCT */ 1192 1193 set_thread_profiler(NULL); 1194 if (FlatProfiler::is_active()) { 1195 // This is where we would decide to either give each thread it's own profiler 1196 // or use one global one from FlatProfiler, 1197 // or up to some count of the number of profiled threads, etc. 1198 ThreadProfiler* pp = new ThreadProfiler(); 1199 pp->engage(); 1200 set_thread_profiler(pp); 1201 } 1202 1203 // Setup safepoint state info for this thread 1204 ThreadSafepointState::create(this); 1205 1206 debug_only(_java_call_counter = 0); 1207 1208 // JVMTI PopFrame support 1209 _popframe_condition = popframe_inactive; 1210 _popframe_preserved_args = NULL; 1211 _popframe_preserved_args_size = 0; 1212 1213 pd_initialize(); 1214} 1215 1216#ifndef SERIALGC 1217SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1218DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1219#endif // !SERIALGC 1220 1221JavaThread::JavaThread(bool is_attaching) : 1222 Thread() 1223#ifndef SERIALGC 1224 , _satb_mark_queue(&_satb_mark_queue_set), 1225 _dirty_card_queue(&_dirty_card_queue_set) 1226#endif // !SERIALGC 1227{ 1228 initialize(); 1229 _is_attaching = is_attaching; 1230} 1231 1232bool JavaThread::reguard_stack(address cur_sp) { 1233 if (_stack_guard_state != stack_guard_yellow_disabled) { 1234 return true; // Stack already guarded or guard pages not needed. 1235 } 1236 1237 if (register_stack_overflow()) { 1238 // For those architectures which have separate register and 1239 // memory stacks, we must check the register stack to see if 1240 // it has overflowed. 1241 return false; 1242 } 1243 1244 // Java code never executes within the yellow zone: the latter is only 1245 // there to provoke an exception during stack banging. If java code 1246 // is executing there, either StackShadowPages should be larger, or 1247 // some exception code in c1, c2 or the interpreter isn't unwinding 1248 // when it should. 1249 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1250 1251 enable_stack_yellow_zone(); 1252 return true; 1253} 1254 1255bool JavaThread::reguard_stack(void) { 1256 return reguard_stack(os::current_stack_pointer()); 1257} 1258 1259 1260void JavaThread::block_if_vm_exited() { 1261 if (_terminated == _vm_exited) { 1262 // _vm_exited is set at safepoint, and Threads_lock is never released 1263 // we will block here forever 1264 Threads_lock->lock_without_safepoint_check(); 1265 ShouldNotReachHere(); 1266 } 1267} 1268 1269 1270// Remove this ifdef when C1 is ported to the compiler interface. 1271static void compiler_thread_entry(JavaThread* thread, TRAPS); 1272 1273JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1274 Thread() 1275#ifndef SERIALGC 1276 , _satb_mark_queue(&_satb_mark_queue_set), 1277 _dirty_card_queue(&_dirty_card_queue_set) 1278#endif // !SERIALGC 1279{ 1280 if (TraceThreadEvents) { 1281 tty->print_cr("creating thread %p", this); 1282 } 1283 initialize(); 1284 _is_attaching = false; 1285 set_entry_point(entry_point); 1286 // Create the native thread itself. 1287 // %note runtime_23 1288 os::ThreadType thr_type = os::java_thread; 1289 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1290 os::java_thread; 1291 os::create_thread(this, thr_type, stack_sz); 1292 1293 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1294 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1295 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1296 // the exception consists of creating the exception object & initializing it, initialization 1297 // will leave the VM via a JavaCall and then all locks must be unlocked). 1298 // 1299 // The thread is still suspended when we reach here. Thread must be explicit started 1300 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1301 // by calling Threads:add. The reason why this is not done here, is because the thread 1302 // object must be fully initialized (take a look at JVM_Start) 1303} 1304 1305JavaThread::~JavaThread() { 1306 if (TraceThreadEvents) { 1307 tty->print_cr("terminate thread %p", this); 1308 } 1309 1310 // JSR166 -- return the parker to the free list 1311 Parker::Release(_parker); 1312 _parker = NULL ; 1313 1314 // Free any remaining previous UnrollBlock 1315 vframeArray* old_array = vframe_array_last(); 1316 1317 if (old_array != NULL) { 1318 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1319 old_array->set_unroll_block(NULL); 1320 delete old_info; 1321 delete old_array; 1322 } 1323 1324 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1325 if (deferred != NULL) { 1326 // This can only happen if thread is destroyed before deoptimization occurs. 1327 assert(deferred->length() != 0, "empty array!"); 1328 do { 1329 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1330 deferred->remove_at(0); 1331 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1332 delete dlv; 1333 } while (deferred->length() != 0); 1334 delete deferred; 1335 } 1336 1337 // All Java related clean up happens in exit 1338 ThreadSafepointState::destroy(this); 1339 if (_thread_profiler != NULL) delete _thread_profiler; 1340 if (_thread_stat != NULL) delete _thread_stat; 1341} 1342 1343 1344// The first routine called by a new Java thread 1345void JavaThread::run() { 1346 // initialize thread-local alloc buffer related fields 1347 this->initialize_tlab(); 1348 1349 // used to test validitity of stack trace backs 1350 this->record_base_of_stack_pointer(); 1351 1352 // Record real stack base and size. 1353 this->record_stack_base_and_size(); 1354 1355 // Initialize thread local storage; set before calling MutexLocker 1356 this->initialize_thread_local_storage(); 1357 1358 this->create_stack_guard_pages(); 1359 1360 // Thread is now sufficient initialized to be handled by the safepoint code as being 1361 // in the VM. Change thread state from _thread_new to _thread_in_vm 1362 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1363 1364 assert(JavaThread::current() == this, "sanity check"); 1365 assert(!Thread::current()->owns_locks(), "sanity check"); 1366 1367 DTRACE_THREAD_PROBE(start, this); 1368 1369 // This operation might block. We call that after all safepoint checks for a new thread has 1370 // been completed. 1371 this->set_active_handles(JNIHandleBlock::allocate_block()); 1372 1373 if (JvmtiExport::should_post_thread_life()) { 1374 JvmtiExport::post_thread_start(this); 1375 } 1376 1377 // We call another function to do the rest so we are sure that the stack addresses used 1378 // from there will be lower than the stack base just computed 1379 thread_main_inner(); 1380 1381 // Note, thread is no longer valid at this point! 1382} 1383 1384 1385void JavaThread::thread_main_inner() { 1386 assert(JavaThread::current() == this, "sanity check"); 1387 assert(this->threadObj() != NULL, "just checking"); 1388 1389 // Execute thread entry point. If this thread is being asked to restart, 1390 // or has been stopped before starting, do not reexecute entry point. 1391 // Note: Due to JVM_StopThread we can have pending exceptions already! 1392 if (!this->has_pending_exception() && !java_lang_Thread::is_stillborn(this->threadObj())) { 1393 // enter the thread's entry point only if we have no pending exceptions 1394 HandleMark hm(this); 1395 this->entry_point()(this, this); 1396 } 1397 1398 DTRACE_THREAD_PROBE(stop, this); 1399 1400 this->exit(false); 1401 delete this; 1402} 1403 1404 1405static void ensure_join(JavaThread* thread) { 1406 // We do not need to grap the Threads_lock, since we are operating on ourself. 1407 Handle threadObj(thread, thread->threadObj()); 1408 assert(threadObj.not_null(), "java thread object must exist"); 1409 ObjectLocker lock(threadObj, thread); 1410 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1411 thread->clear_pending_exception(); 1412 // It is of profound importance that we set the stillborn bit and reset the thread object, 1413 // before we do the notify. Since, changing these two variable will make JVM_IsAlive return 1414 // false. So in case another thread is doing a join on this thread , it will detect that the thread 1415 // is dead when it gets notified. 1416 java_lang_Thread::set_stillborn(threadObj()); 1417 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1418 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1419 java_lang_Thread::set_thread(threadObj(), NULL); 1420 lock.notify_all(thread); 1421 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1422 thread->clear_pending_exception(); 1423} 1424 1425// For any new cleanup additions, please check to see if they need to be applied to 1426// cleanup_failed_attach_current_thread as well. 1427void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1428 assert(this == JavaThread::current(), "thread consistency check"); 1429 if (!InitializeJavaLangSystem) return; 1430 1431 HandleMark hm(this); 1432 Handle uncaught_exception(this, this->pending_exception()); 1433 this->clear_pending_exception(); 1434 Handle threadObj(this, this->threadObj()); 1435 assert(threadObj.not_null(), "Java thread object should be created"); 1436 1437 if (get_thread_profiler() != NULL) { 1438 get_thread_profiler()->disengage(); 1439 ResourceMark rm; 1440 get_thread_profiler()->print(get_thread_name()); 1441 } 1442 1443 1444 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1445 { 1446 EXCEPTION_MARK; 1447 1448 CLEAR_PENDING_EXCEPTION; 1449 } 1450 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1451 // has to be fixed by a runtime query method 1452 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1453 // JSR-166: change call from from ThreadGroup.uncaughtException to 1454 // java.lang.Thread.dispatchUncaughtException 1455 if (uncaught_exception.not_null()) { 1456 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1457 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT", 1458 (address)uncaught_exception(), (address)threadObj(), (address)group()); 1459 { 1460 EXCEPTION_MARK; 1461 // Check if the method Thread.dispatchUncaughtException() exists. If so 1462 // call it. Otherwise we have an older library without the JSR-166 changes, 1463 // so call ThreadGroup.uncaughtException() 1464 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1465 CallInfo callinfo; 1466 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass()); 1467 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1468 vmSymbolHandles::dispatchUncaughtException_name(), 1469 vmSymbolHandles::throwable_void_signature(), 1470 KlassHandle(), false, false, THREAD); 1471 CLEAR_PENDING_EXCEPTION; 1472 methodHandle method = callinfo.selected_method(); 1473 if (method.not_null()) { 1474 JavaValue result(T_VOID); 1475 JavaCalls::call_virtual(&result, 1476 threadObj, thread_klass, 1477 vmSymbolHandles::dispatchUncaughtException_name(), 1478 vmSymbolHandles::throwable_void_signature(), 1479 uncaught_exception, 1480 THREAD); 1481 } else { 1482 KlassHandle thread_group(THREAD, SystemDictionary::threadGroup_klass()); 1483 JavaValue result(T_VOID); 1484 JavaCalls::call_virtual(&result, 1485 group, thread_group, 1486 vmSymbolHandles::uncaughtException_name(), 1487 vmSymbolHandles::thread_throwable_void_signature(), 1488 threadObj, // Arg 1 1489 uncaught_exception, // Arg 2 1490 THREAD); 1491 } 1492 CLEAR_PENDING_EXCEPTION; 1493 } 1494 } 1495 1496 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1497 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1498 // is deprecated anyhow. 1499 { int count = 3; 1500 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1501 EXCEPTION_MARK; 1502 JavaValue result(T_VOID); 1503 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass()); 1504 JavaCalls::call_virtual(&result, 1505 threadObj, thread_klass, 1506 vmSymbolHandles::exit_method_name(), 1507 vmSymbolHandles::void_method_signature(), 1508 THREAD); 1509 CLEAR_PENDING_EXCEPTION; 1510 } 1511 } 1512 1513 // notify JVMTI 1514 if (JvmtiExport::should_post_thread_life()) { 1515 JvmtiExport::post_thread_end(this); 1516 } 1517 1518 // We have notified the agents that we are exiting, before we go on, 1519 // we must check for a pending external suspend request and honor it 1520 // in order to not surprise the thread that made the suspend request. 1521 while (true) { 1522 { 1523 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1524 if (!is_external_suspend()) { 1525 set_terminated(_thread_exiting); 1526 ThreadService::current_thread_exiting(this); 1527 break; 1528 } 1529 // Implied else: 1530 // Things get a little tricky here. We have a pending external 1531 // suspend request, but we are holding the SR_lock so we 1532 // can't just self-suspend. So we temporarily drop the lock 1533 // and then self-suspend. 1534 } 1535 1536 ThreadBlockInVM tbivm(this); 1537 java_suspend_self(); 1538 1539 // We're done with this suspend request, but we have to loop around 1540 // and check again. Eventually we will get SR_lock without a pending 1541 // external suspend request and will be able to mark ourselves as 1542 // exiting. 1543 } 1544 // no more external suspends are allowed at this point 1545 } else { 1546 // before_exit() has already posted JVMTI THREAD_END events 1547 } 1548 1549 // Notify waiters on thread object. This has to be done after exit() is called 1550 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1551 // group should have the destroyed bit set before waiters are notified). 1552 ensure_join(this); 1553 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1554 1555 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1556 // held by this thread must be released. A detach operation must only 1557 // get here if there are no Java frames on the stack. Therefore, any 1558 // owned monitors at this point MUST be JNI-acquired monitors which are 1559 // pre-inflated and in the monitor cache. 1560 // 1561 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1562 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1563 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1564 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1565 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1566 } 1567 1568 // These things needs to be done while we are still a Java Thread. Make sure that thread 1569 // is in a consistent state, in case GC happens 1570 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1571 1572 if (active_handles() != NULL) { 1573 JNIHandleBlock* block = active_handles(); 1574 set_active_handles(NULL); 1575 JNIHandleBlock::release_block(block); 1576 } 1577 1578 if (free_handle_block() != NULL) { 1579 JNIHandleBlock* block = free_handle_block(); 1580 set_free_handle_block(NULL); 1581 JNIHandleBlock::release_block(block); 1582 } 1583 1584 // These have to be removed while this is still a valid thread. 1585 remove_stack_guard_pages(); 1586 1587 if (UseTLAB) { 1588 tlab().make_parsable(true); // retire TLAB 1589 } 1590 1591 if (jvmti_thread_state() != NULL) { 1592 JvmtiExport::cleanup_thread(this); 1593 } 1594 1595 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1596 Threads::remove(this); 1597} 1598 1599void JavaThread::cleanup_failed_attach_current_thread() { 1600 1601 if (get_thread_profiler() != NULL) { 1602 get_thread_profiler()->disengage(); 1603 ResourceMark rm; 1604 get_thread_profiler()->print(get_thread_name()); 1605 } 1606 1607 if (active_handles() != NULL) { 1608 JNIHandleBlock* block = active_handles(); 1609 set_active_handles(NULL); 1610 JNIHandleBlock::release_block(block); 1611 } 1612 1613 if (free_handle_block() != NULL) { 1614 JNIHandleBlock* block = free_handle_block(); 1615 set_free_handle_block(NULL); 1616 JNIHandleBlock::release_block(block); 1617 } 1618 1619 if (UseTLAB) { 1620 tlab().make_parsable(true); // retire TLAB, if any 1621 } 1622 1623 Threads::remove(this); 1624 delete this; 1625} 1626 1627 1628JavaThread* JavaThread::active() { 1629 Thread* thread = ThreadLocalStorage::thread(); 1630 assert(thread != NULL, "just checking"); 1631 if (thread->is_Java_thread()) { 1632 return (JavaThread*) thread; 1633 } else { 1634 assert(thread->is_VM_thread(), "this must be a vm thread"); 1635 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1636 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1637 assert(ret->is_Java_thread(), "must be a Java thread"); 1638 return ret; 1639 } 1640} 1641 1642bool JavaThread::is_lock_owned(address adr) const { 1643 if (lock_is_in_stack(adr)) return true; 1644 1645 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1646 if (chunk->contains(adr)) return true; 1647 } 1648 1649 return false; 1650} 1651 1652 1653void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1654 chunk->set_next(monitor_chunks()); 1655 set_monitor_chunks(chunk); 1656} 1657 1658void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1659 guarantee(monitor_chunks() != NULL, "must be non empty"); 1660 if (monitor_chunks() == chunk) { 1661 set_monitor_chunks(chunk->next()); 1662 } else { 1663 MonitorChunk* prev = monitor_chunks(); 1664 while (prev->next() != chunk) prev = prev->next(); 1665 prev->set_next(chunk->next()); 1666 } 1667} 1668 1669// JVM support. 1670 1671// Note: this function shouldn't block if it's called in 1672// _thread_in_native_trans state (such as from 1673// check_special_condition_for_native_trans()). 1674void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 1675 1676 if (has_last_Java_frame() && has_async_condition()) { 1677 // If we are at a polling page safepoint (not a poll return) 1678 // then we must defer async exception because live registers 1679 // will be clobbered by the exception path. Poll return is 1680 // ok because the call we a returning from already collides 1681 // with exception handling registers and so there is no issue. 1682 // (The exception handling path kills call result registers but 1683 // this is ok since the exception kills the result anyway). 1684 1685 if (is_at_poll_safepoint()) { 1686 // if the code we are returning to has deoptimized we must defer 1687 // the exception otherwise live registers get clobbered on the 1688 // exception path before deoptimization is able to retrieve them. 1689 // 1690 RegisterMap map(this, false); 1691 frame caller_fr = last_frame().sender(&map); 1692 assert(caller_fr.is_compiled_frame(), "what?"); 1693 if (caller_fr.is_deoptimized_frame()) { 1694 if (TraceExceptions) { 1695 ResourceMark rm; 1696 tty->print_cr("deferred async exception at compiled safepoint"); 1697 } 1698 return; 1699 } 1700 } 1701 } 1702 1703 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 1704 if (condition == _no_async_condition) { 1705 // Conditions have changed since has_special_runtime_exit_condition() 1706 // was called: 1707 // - if we were here only because of an external suspend request, 1708 // then that was taken care of above (or cancelled) so we are done 1709 // - if we were here because of another async request, then it has 1710 // been cleared between the has_special_runtime_exit_condition() 1711 // and now so again we are done 1712 return; 1713 } 1714 1715 // Check for pending async. exception 1716 if (_pending_async_exception != NULL) { 1717 // Only overwrite an already pending exception, if it is not a threadDeath. 1718 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::threaddeath_klass())) { 1719 1720 // We cannot call Exceptions::_throw(...) here because we cannot block 1721 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 1722 1723 if (TraceExceptions) { 1724 ResourceMark rm; 1725 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 1726 if (has_last_Java_frame() ) { 1727 frame f = last_frame(); 1728 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 1729 } 1730 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name()); 1731 } 1732 _pending_async_exception = NULL; 1733 clear_has_async_exception(); 1734 } 1735 } 1736 1737 if (check_unsafe_error && 1738 condition == _async_unsafe_access_error && !has_pending_exception()) { 1739 condition = _no_async_condition; // done 1740 switch (thread_state()) { 1741 case _thread_in_vm: 1742 { 1743 JavaThread* THREAD = this; 1744 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 1745 } 1746 case _thread_in_native: 1747 { 1748 ThreadInVMfromNative tiv(this); 1749 JavaThread* THREAD = this; 1750 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 1751 } 1752 case _thread_in_Java: 1753 { 1754 ThreadInVMfromJava tiv(this); 1755 JavaThread* THREAD = this; 1756 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 1757 } 1758 default: 1759 ShouldNotReachHere(); 1760 } 1761 } 1762 1763 assert(condition == _no_async_condition || has_pending_exception() || 1764 (!check_unsafe_error && condition == _async_unsafe_access_error), 1765 "must have handled the async condition, if no exception"); 1766} 1767 1768void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 1769 // 1770 // Check for pending external suspend. Internal suspend requests do 1771 // not use handle_special_runtime_exit_condition(). 1772 // If JNIEnv proxies are allowed, don't self-suspend if the target 1773 // thread is not the current thread. In older versions of jdbx, jdbx 1774 // threads could call into the VM with another thread's JNIEnv so we 1775 // can be here operating on behalf of a suspended thread (4432884). 1776 bool do_self_suspend = is_external_suspend_with_lock(); 1777 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 1778 // 1779 // Because thread is external suspended the safepoint code will count 1780 // thread as at a safepoint. This can be odd because we can be here 1781 // as _thread_in_Java which would normally transition to _thread_blocked 1782 // at a safepoint. We would like to mark the thread as _thread_blocked 1783 // before calling java_suspend_self like all other callers of it but 1784 // we must then observe proper safepoint protocol. (We can't leave 1785 // _thread_blocked with a safepoint in progress). However we can be 1786 // here as _thread_in_native_trans so we can't use a normal transition 1787 // constructor/destructor pair because they assert on that type of 1788 // transition. We could do something like: 1789 // 1790 // JavaThreadState state = thread_state(); 1791 // set_thread_state(_thread_in_vm); 1792 // { 1793 // ThreadBlockInVM tbivm(this); 1794 // java_suspend_self() 1795 // } 1796 // set_thread_state(_thread_in_vm_trans); 1797 // if (safepoint) block; 1798 // set_thread_state(state); 1799 // 1800 // but that is pretty messy. Instead we just go with the way the 1801 // code has worked before and note that this is the only path to 1802 // java_suspend_self that doesn't put the thread in _thread_blocked 1803 // mode. 1804 1805 frame_anchor()->make_walkable(this); 1806 java_suspend_self(); 1807 1808 // We might be here for reasons in addition to the self-suspend request 1809 // so check for other async requests. 1810 } 1811 1812 if (check_asyncs) { 1813 check_and_handle_async_exceptions(); 1814 } 1815} 1816 1817void JavaThread::send_thread_stop(oop java_throwable) { 1818 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 1819 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 1820 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 1821 1822 // Do not throw asynchronous exceptions against the compiler thread 1823 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 1824 if (is_Compiler_thread()) return; 1825 1826 // This is a change from JDK 1.1, but JDK 1.2 will also do it: 1827 if (java_throwable->is_a(SystemDictionary::threaddeath_klass())) { 1828 java_lang_Thread::set_stillborn(threadObj()); 1829 } 1830 1831 { 1832 // Actually throw the Throwable against the target Thread - however 1833 // only if there is no thread death exception installed already. 1834 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::threaddeath_klass())) { 1835 // If the topmost frame is a runtime stub, then we are calling into 1836 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 1837 // must deoptimize the caller before continuing, as the compiled exception handler table 1838 // may not be valid 1839 if (has_last_Java_frame()) { 1840 frame f = last_frame(); 1841 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 1842 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 1843 RegisterMap reg_map(this, UseBiasedLocking); 1844 frame compiled_frame = f.sender(®_map); 1845 if (compiled_frame.can_be_deoptimized()) { 1846 Deoptimization::deoptimize(this, compiled_frame, ®_map); 1847 } 1848 } 1849 } 1850 1851 // Set async. pending exception in thread. 1852 set_pending_async_exception(java_throwable); 1853 1854 if (TraceExceptions) { 1855 ResourceMark rm; 1856 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name()); 1857 } 1858 // for AbortVMOnException flag 1859 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name())); 1860 } 1861 } 1862 1863 1864 // Interrupt thread so it will wake up from a potential wait() 1865 Thread::interrupt(this); 1866} 1867 1868// External suspension mechanism. 1869// 1870// Tell the VM to suspend a thread when ever it knows that it does not hold on 1871// to any VM_locks and it is at a transition 1872// Self-suspension will happen on the transition out of the vm. 1873// Catch "this" coming in from JNIEnv pointers when the thread has been freed 1874// 1875// Guarantees on return: 1876// + Target thread will not execute any new bytecode (that's why we need to 1877// force a safepoint) 1878// + Target thread will not enter any new monitors 1879// 1880void JavaThread::java_suspend() { 1881 { MutexLocker mu(Threads_lock); 1882 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 1883 return; 1884 } 1885 } 1886 1887 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1888 if (!is_external_suspend()) { 1889 // a racing resume has cancelled us; bail out now 1890 return; 1891 } 1892 1893 // suspend is done 1894 uint32_t debug_bits = 0; 1895 // Warning: is_ext_suspend_completed() may temporarily drop the 1896 // SR_lock to allow the thread to reach a stable thread state if 1897 // it is currently in a transient thread state. 1898 if (is_ext_suspend_completed(false /* !called_by_wait */, 1899 SuspendRetryDelay, &debug_bits) ) { 1900 return; 1901 } 1902 } 1903 1904 VM_ForceSafepoint vm_suspend; 1905 VMThread::execute(&vm_suspend); 1906} 1907 1908// Part II of external suspension. 1909// A JavaThread self suspends when it detects a pending external suspend 1910// request. This is usually on transitions. It is also done in places 1911// where continuing to the next transition would surprise the caller, 1912// e.g., monitor entry. 1913// 1914// Returns the number of times that the thread self-suspended. 1915// 1916// Note: DO NOT call java_suspend_self() when you just want to block current 1917// thread. java_suspend_self() is the second stage of cooperative 1918// suspension for external suspend requests and should only be used 1919// to complete an external suspend request. 1920// 1921int JavaThread::java_suspend_self() { 1922 int ret = 0; 1923 1924 // we are in the process of exiting so don't suspend 1925 if (is_exiting()) { 1926 clear_external_suspend(); 1927 return ret; 1928 } 1929 1930 assert(_anchor.walkable() || 1931 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 1932 "must have walkable stack"); 1933 1934 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1935 1936 assert(!this->is_any_suspended(), 1937 "a thread trying to self-suspend should not already be suspended"); 1938 1939 if (this->is_suspend_equivalent()) { 1940 // If we are self-suspending as a result of the lifting of a 1941 // suspend equivalent condition, then the suspend_equivalent 1942 // flag is not cleared until we set the ext_suspended flag so 1943 // that wait_for_ext_suspend_completion() returns consistent 1944 // results. 1945 this->clear_suspend_equivalent(); 1946 } 1947 1948 // A racing resume may have cancelled us before we grabbed SR_lock 1949 // above. Or another external suspend request could be waiting for us 1950 // by the time we return from SR_lock()->wait(). The thread 1951 // that requested the suspension may already be trying to walk our 1952 // stack and if we return now, we can change the stack out from under 1953 // it. This would be a "bad thing (TM)" and cause the stack walker 1954 // to crash. We stay self-suspended until there are no more pending 1955 // external suspend requests. 1956 while (is_external_suspend()) { 1957 ret++; 1958 this->set_ext_suspended(); 1959 1960 // _ext_suspended flag is cleared by java_resume() 1961 while (is_ext_suspended()) { 1962 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 1963 } 1964 } 1965 1966 return ret; 1967} 1968 1969#ifdef ASSERT 1970// verify the JavaThread has not yet been published in the Threads::list, and 1971// hence doesn't need protection from concurrent access at this stage 1972void JavaThread::verify_not_published() { 1973 if (!Threads_lock->owned_by_self()) { 1974 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 1975 assert( !Threads::includes(this), 1976 "java thread shouldn't have been published yet!"); 1977 } 1978 else { 1979 assert( !Threads::includes(this), 1980 "java thread shouldn't have been published yet!"); 1981 } 1982} 1983#endif 1984 1985// Slow path when the native==>VM/Java barriers detect a safepoint is in 1986// progress or when _suspend_flags is non-zero. 1987// Current thread needs to self-suspend if there is a suspend request and/or 1988// block if a safepoint is in progress. 1989// Async exception ISN'T checked. 1990// Note only the ThreadInVMfromNative transition can call this function 1991// directly and when thread state is _thread_in_native_trans 1992void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 1993 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 1994 1995 JavaThread *curJT = JavaThread::current(); 1996 bool do_self_suspend = thread->is_external_suspend(); 1997 1998 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 1999 2000 // If JNIEnv proxies are allowed, don't self-suspend if the target 2001 // thread is not the current thread. In older versions of jdbx, jdbx 2002 // threads could call into the VM with another thread's JNIEnv so we 2003 // can be here operating on behalf of a suspended thread (4432884). 2004 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2005 JavaThreadState state = thread->thread_state(); 2006 2007 // We mark this thread_blocked state as a suspend-equivalent so 2008 // that a caller to is_ext_suspend_completed() won't be confused. 2009 // The suspend-equivalent state is cleared by java_suspend_self(). 2010 thread->set_suspend_equivalent(); 2011 2012 // If the safepoint code sees the _thread_in_native_trans state, it will 2013 // wait until the thread changes to other thread state. There is no 2014 // guarantee on how soon we can obtain the SR_lock and complete the 2015 // self-suspend request. It would be a bad idea to let safepoint wait for 2016 // too long. Temporarily change the state to _thread_blocked to 2017 // let the VM thread know that this thread is ready for GC. The problem 2018 // of changing thread state is that safepoint could happen just after 2019 // java_suspend_self() returns after being resumed, and VM thread will 2020 // see the _thread_blocked state. We must check for safepoint 2021 // after restoring the state and make sure we won't leave while a safepoint 2022 // is in progress. 2023 thread->set_thread_state(_thread_blocked); 2024 thread->java_suspend_self(); 2025 thread->set_thread_state(state); 2026 // Make sure new state is seen by VM thread 2027 if (os::is_MP()) { 2028 if (UseMembar) { 2029 // Force a fence between the write above and read below 2030 OrderAccess::fence(); 2031 } else { 2032 // Must use this rather than serialization page in particular on Windows 2033 InterfaceSupport::serialize_memory(thread); 2034 } 2035 } 2036 } 2037 2038 if (SafepointSynchronize::do_call_back()) { 2039 // If we are safepointing, then block the caller which may not be 2040 // the same as the target thread (see above). 2041 SafepointSynchronize::block(curJT); 2042 } 2043 2044 if (thread->is_deopt_suspend()) { 2045 thread->clear_deopt_suspend(); 2046 RegisterMap map(thread, false); 2047 frame f = thread->last_frame(); 2048 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2049 f = f.sender(&map); 2050 } 2051 if (f.id() == thread->must_deopt_id()) { 2052 thread->clear_must_deopt_id(); 2053 // Since we know we're safe to deopt the current state is a safe state 2054 f.deoptimize(thread, true); 2055 } else { 2056 fatal("missed deoptimization!"); 2057 } 2058 } 2059} 2060 2061// Slow path when the native==>VM/Java barriers detect a safepoint is in 2062// progress or when _suspend_flags is non-zero. 2063// Current thread needs to self-suspend if there is a suspend request and/or 2064// block if a safepoint is in progress. 2065// Also check for pending async exception (not including unsafe access error). 2066// Note only the native==>VM/Java barriers can call this function and when 2067// thread state is _thread_in_native_trans. 2068void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2069 check_safepoint_and_suspend_for_native_trans(thread); 2070 2071 if (thread->has_async_exception()) { 2072 // We are in _thread_in_native_trans state, don't handle unsafe 2073 // access error since that may block. 2074 thread->check_and_handle_async_exceptions(false); 2075 } 2076} 2077 2078// We need to guarantee the Threads_lock here, since resumes are not 2079// allowed during safepoint synchronization 2080// Can only resume from an external suspension 2081void JavaThread::java_resume() { 2082 assert_locked_or_safepoint(Threads_lock); 2083 2084 // Sanity check: thread is gone, has started exiting or the thread 2085 // was not externally suspended. 2086 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2087 return; 2088 } 2089 2090 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2091 2092 clear_external_suspend(); 2093 2094 if (is_ext_suspended()) { 2095 clear_ext_suspended(); 2096 SR_lock()->notify_all(); 2097 } 2098} 2099 2100void JavaThread::create_stack_guard_pages() { 2101 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2102 address low_addr = stack_base() - stack_size(); 2103 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2104 2105 int allocate = os::allocate_stack_guard_pages(); 2106 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2107 2108 if (allocate && !os::commit_memory((char *) low_addr, len)) { 2109 warning("Attempt to allocate stack guard pages failed."); 2110 return; 2111 } 2112 2113 if (os::guard_memory((char *) low_addr, len)) { 2114 _stack_guard_state = stack_guard_enabled; 2115 } else { 2116 warning("Attempt to protect stack guard pages failed."); 2117 if (os::uncommit_memory((char *) low_addr, len)) { 2118 warning("Attempt to deallocate stack guard pages failed."); 2119 } 2120 } 2121} 2122 2123void JavaThread::remove_stack_guard_pages() { 2124 if (_stack_guard_state == stack_guard_unused) return; 2125 address low_addr = stack_base() - stack_size(); 2126 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2127 2128 if (os::allocate_stack_guard_pages()) { 2129 if (os::uncommit_memory((char *) low_addr, len)) { 2130 _stack_guard_state = stack_guard_unused; 2131 } else { 2132 warning("Attempt to deallocate stack guard pages failed."); 2133 } 2134 } else { 2135 if (_stack_guard_state == stack_guard_unused) return; 2136 if (os::unguard_memory((char *) low_addr, len)) { 2137 _stack_guard_state = stack_guard_unused; 2138 } else { 2139 warning("Attempt to unprotect stack guard pages failed."); 2140 } 2141 } 2142} 2143 2144void JavaThread::enable_stack_yellow_zone() { 2145 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2146 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2147 2148 // The base notation is from the stacks point of view, growing downward. 2149 // We need to adjust it to work correctly with guard_memory() 2150 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2151 2152 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2153 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2154 2155 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2156 _stack_guard_state = stack_guard_enabled; 2157 } else { 2158 warning("Attempt to guard stack yellow zone failed."); 2159 } 2160 enable_register_stack_guard(); 2161} 2162 2163void JavaThread::disable_stack_yellow_zone() { 2164 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2165 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2166 2167 // Simply return if called for a thread that does not use guard pages. 2168 if (_stack_guard_state == stack_guard_unused) return; 2169 2170 // The base notation is from the stacks point of view, growing downward. 2171 // We need to adjust it to work correctly with guard_memory() 2172 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2173 2174 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2175 _stack_guard_state = stack_guard_yellow_disabled; 2176 } else { 2177 warning("Attempt to unguard stack yellow zone failed."); 2178 } 2179 disable_register_stack_guard(); 2180} 2181 2182void JavaThread::enable_stack_red_zone() { 2183 // The base notation is from the stacks point of view, growing downward. 2184 // We need to adjust it to work correctly with guard_memory() 2185 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2186 address base = stack_red_zone_base() - stack_red_zone_size(); 2187 2188 guarantee(base < stack_base(),"Error calculating stack red zone"); 2189 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2190 2191 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2192 warning("Attempt to guard stack red zone failed."); 2193 } 2194} 2195 2196void JavaThread::disable_stack_red_zone() { 2197 // The base notation is from the stacks point of view, growing downward. 2198 // We need to adjust it to work correctly with guard_memory() 2199 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2200 address base = stack_red_zone_base() - stack_red_zone_size(); 2201 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2202 warning("Attempt to unguard stack red zone failed."); 2203 } 2204} 2205 2206void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2207 // ignore is there is no stack 2208 if (!has_last_Java_frame()) return; 2209 // traverse the stack frames. Starts from top frame. 2210 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2211 frame* fr = fst.current(); 2212 f(fr, fst.register_map()); 2213 } 2214} 2215 2216 2217#ifndef PRODUCT 2218// Deoptimization 2219// Function for testing deoptimization 2220void JavaThread::deoptimize() { 2221 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2222 StackFrameStream fst(this, UseBiasedLocking); 2223 bool deopt = false; // Dump stack only if a deopt actually happens. 2224 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2225 // Iterate over all frames in the thread and deoptimize 2226 for(; !fst.is_done(); fst.next()) { 2227 if(fst.current()->can_be_deoptimized()) { 2228 2229 if (only_at) { 2230 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2231 // consists of comma or carriage return separated numbers so 2232 // search for the current bci in that string. 2233 address pc = fst.current()->pc(); 2234 nmethod* nm = (nmethod*) fst.current()->cb(); 2235 ScopeDesc* sd = nm->scope_desc_at( pc); 2236 char buffer[8]; 2237 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2238 size_t len = strlen(buffer); 2239 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2240 while (found != NULL) { 2241 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2242 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2243 // Check that the bci found is bracketed by terminators. 2244 break; 2245 } 2246 found = strstr(found + 1, buffer); 2247 } 2248 if (!found) { 2249 continue; 2250 } 2251 } 2252 2253 if (DebugDeoptimization && !deopt) { 2254 deopt = true; // One-time only print before deopt 2255 tty->print_cr("[BEFORE Deoptimization]"); 2256 trace_frames(); 2257 trace_stack(); 2258 } 2259 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2260 } 2261 } 2262 2263 if (DebugDeoptimization && deopt) { 2264 tty->print_cr("[AFTER Deoptimization]"); 2265 trace_frames(); 2266 } 2267} 2268 2269 2270// Make zombies 2271void JavaThread::make_zombies() { 2272 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2273 if (fst.current()->can_be_deoptimized()) { 2274 // it is a Java nmethod 2275 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2276 nm->make_not_entrant(); 2277 } 2278 } 2279} 2280#endif // PRODUCT 2281 2282 2283void JavaThread::deoptimized_wrt_marked_nmethods() { 2284 if (!has_last_Java_frame()) return; 2285 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2286 StackFrameStream fst(this, UseBiasedLocking); 2287 for(; !fst.is_done(); fst.next()) { 2288 if (fst.current()->should_be_deoptimized()) { 2289 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2290 } 2291 } 2292} 2293 2294 2295// GC support 2296static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2297 2298void JavaThread::gc_epilogue() { 2299 frames_do(frame_gc_epilogue); 2300} 2301 2302 2303static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2304 2305void JavaThread::gc_prologue() { 2306 frames_do(frame_gc_prologue); 2307} 2308 2309 2310void JavaThread::oops_do(OopClosure* f) { 2311 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2312 // since there may be more than one thread using each ThreadProfiler. 2313 2314 // Traverse the GCHandles 2315 Thread::oops_do(f); 2316 2317 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2318 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2319 2320 if (has_last_Java_frame()) { 2321 2322 // Traverse the privileged stack 2323 if (_privileged_stack_top != NULL) { 2324 _privileged_stack_top->oops_do(f); 2325 } 2326 2327 // traverse the registered growable array 2328 if (_array_for_gc != NULL) { 2329 for (int index = 0; index < _array_for_gc->length(); index++) { 2330 f->do_oop(_array_for_gc->adr_at(index)); 2331 } 2332 } 2333 2334 // Traverse the monitor chunks 2335 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2336 chunk->oops_do(f); 2337 } 2338 2339 // Traverse the execution stack 2340 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2341 fst.current()->oops_do(f, fst.register_map()); 2342 } 2343 } 2344 2345 // callee_target is never live across a gc point so NULL it here should 2346 // it still contain a methdOop. 2347 2348 set_callee_target(NULL); 2349 2350 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2351 // If we have deferred set_locals there might be oops waiting to be 2352 // written 2353 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2354 if (list != NULL) { 2355 for (int i = 0; i < list->length(); i++) { 2356 list->at(i)->oops_do(f); 2357 } 2358 } 2359 2360 // Traverse instance variables at the end since the GC may be moving things 2361 // around using this function 2362 f->do_oop((oop*) &_threadObj); 2363 f->do_oop((oop*) &_vm_result); 2364 f->do_oop((oop*) &_vm_result_2); 2365 f->do_oop((oop*) &_exception_oop); 2366 f->do_oop((oop*) &_pending_async_exception); 2367 2368 if (jvmti_thread_state() != NULL) { 2369 jvmti_thread_state()->oops_do(f); 2370 } 2371} 2372 2373void JavaThread::nmethods_do() { 2374 // Traverse the GCHandles 2375 Thread::nmethods_do(); 2376 2377 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2378 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2379 2380 if (has_last_Java_frame()) { 2381 // Traverse the execution stack 2382 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2383 fst.current()->nmethods_do(); 2384 } 2385 } 2386} 2387 2388// Printing 2389const char* _get_thread_state_name(JavaThreadState _thread_state) { 2390 switch (_thread_state) { 2391 case _thread_uninitialized: return "_thread_uninitialized"; 2392 case _thread_new: return "_thread_new"; 2393 case _thread_new_trans: return "_thread_new_trans"; 2394 case _thread_in_native: return "_thread_in_native"; 2395 case _thread_in_native_trans: return "_thread_in_native_trans"; 2396 case _thread_in_vm: return "_thread_in_vm"; 2397 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2398 case _thread_in_Java: return "_thread_in_Java"; 2399 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2400 case _thread_blocked: return "_thread_blocked"; 2401 case _thread_blocked_trans: return "_thread_blocked_trans"; 2402 default: return "unknown thread state"; 2403 } 2404} 2405 2406#ifndef PRODUCT 2407void JavaThread::print_thread_state_on(outputStream *st) const { 2408 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2409}; 2410void JavaThread::print_thread_state() const { 2411 print_thread_state_on(tty); 2412}; 2413#endif // PRODUCT 2414 2415// Called by Threads::print() for VM_PrintThreads operation 2416void JavaThread::print_on(outputStream *st) const { 2417 st->print("\"%s\" ", get_thread_name()); 2418 oop thread_oop = threadObj(); 2419 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2420 Thread::print_on(st); 2421 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2422 st->print_cr("[" INTPTR_FORMAT ".." INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12), highest_lock()); 2423 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2424 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2425 } 2426#ifndef PRODUCT 2427 print_thread_state_on(st); 2428 _safepoint_state->print_on(st); 2429#endif // PRODUCT 2430} 2431 2432// Called by fatal error handler. The difference between this and 2433// JavaThread::print() is that we can't grab lock or allocate memory. 2434void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2435 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2436 oop thread_obj = threadObj(); 2437 if (thread_obj != NULL) { 2438 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2439 } 2440 st->print(" ["); 2441 st->print("%s", _get_thread_state_name(_thread_state)); 2442 if (osthread()) { 2443 st->print(", id=%d", osthread()->thread_id()); 2444 } 2445 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2446 _stack_base - _stack_size, _stack_base); 2447 st->print("]"); 2448 return; 2449} 2450 2451// Verification 2452 2453static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2454 2455void JavaThread::verify() { 2456 // Verify oops in the thread. 2457 oops_do(&VerifyOopClosure::verify_oop); 2458 2459 // Verify the stack frames. 2460 frames_do(frame_verify); 2461} 2462 2463// CR 6300358 (sub-CR 2137150) 2464// Most callers of this method assume that it can't return NULL but a 2465// thread may not have a name whilst it is in the process of attaching to 2466// the VM - see CR 6412693, and there are places where a JavaThread can be 2467// seen prior to having it's threadObj set (eg JNI attaching threads and 2468// if vm exit occurs during initialization). These cases can all be accounted 2469// for such that this method never returns NULL. 2470const char* JavaThread::get_thread_name() const { 2471#ifdef ASSERT 2472 // early safepoints can hit while current thread does not yet have TLS 2473 if (!SafepointSynchronize::is_at_safepoint()) { 2474 Thread *cur = Thread::current(); 2475 if (!(cur->is_Java_thread() && cur == this)) { 2476 // Current JavaThreads are allowed to get their own name without 2477 // the Threads_lock. 2478 assert_locked_or_safepoint(Threads_lock); 2479 } 2480 } 2481#endif // ASSERT 2482 return get_thread_name_string(); 2483} 2484 2485// Returns a non-NULL representation of this thread's name, or a suitable 2486// descriptive string if there is no set name 2487const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2488 const char* name_str; 2489 oop thread_obj = threadObj(); 2490 if (thread_obj != NULL) { 2491 typeArrayOop name = java_lang_Thread::name(thread_obj); 2492 if (name != NULL) { 2493 if (buf == NULL) { 2494 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2495 } 2496 else { 2497 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2498 } 2499 } 2500 else if (is_attaching()) { // workaround for 6412693 - see 6404306 2501 name_str = "<no-name - thread is attaching>"; 2502 } 2503 else { 2504 name_str = Thread::name(); 2505 } 2506 } 2507 else { 2508 name_str = Thread::name(); 2509 } 2510 assert(name_str != NULL, "unexpected NULL thread name"); 2511 return name_str; 2512} 2513 2514 2515const char* JavaThread::get_threadgroup_name() const { 2516 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2517 oop thread_obj = threadObj(); 2518 if (thread_obj != NULL) { 2519 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2520 if (thread_group != NULL) { 2521 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2522 // ThreadGroup.name can be null 2523 if (name != NULL) { 2524 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2525 return str; 2526 } 2527 } 2528 } 2529 return NULL; 2530} 2531 2532const char* JavaThread::get_parent_name() const { 2533 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2534 oop thread_obj = threadObj(); 2535 if (thread_obj != NULL) { 2536 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2537 if (thread_group != NULL) { 2538 oop parent = java_lang_ThreadGroup::parent(thread_group); 2539 if (parent != NULL) { 2540 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2541 // ThreadGroup.name can be null 2542 if (name != NULL) { 2543 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2544 return str; 2545 } 2546 } 2547 } 2548 } 2549 return NULL; 2550} 2551 2552ThreadPriority JavaThread::java_priority() const { 2553 oop thr_oop = threadObj(); 2554 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2555 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2556 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2557 return priority; 2558} 2559 2560void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2561 2562 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2563 // Link Java Thread object <-> C++ Thread 2564 2565 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2566 // and put it into a new Handle. The Handle "thread_oop" can then 2567 // be used to pass the C++ thread object to other methods. 2568 2569 // Set the Java level thread object (jthread) field of the 2570 // new thread (a JavaThread *) to C++ thread object using the 2571 // "thread_oop" handle. 2572 2573 // Set the thread field (a JavaThread *) of the 2574 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2575 2576 Handle thread_oop(Thread::current(), 2577 JNIHandles::resolve_non_null(jni_thread)); 2578 assert(instanceKlass::cast(thread_oop->klass())->is_linked(), 2579 "must be initialized"); 2580 set_threadObj(thread_oop()); 2581 java_lang_Thread::set_thread(thread_oop(), this); 2582 2583 if (prio == NoPriority) { 2584 prio = java_lang_Thread::priority(thread_oop()); 2585 assert(prio != NoPriority, "A valid priority should be present"); 2586 } 2587 2588 // Push the Java priority down to the native thread; needs Threads_lock 2589 Thread::set_priority(this, prio); 2590 2591 // Add the new thread to the Threads list and set it in motion. 2592 // We must have threads lock in order to call Threads::add. 2593 // It is crucial that we do not block before the thread is 2594 // added to the Threads list for if a GC happens, then the java_thread oop 2595 // will not be visited by GC. 2596 Threads::add(this); 2597} 2598 2599oop JavaThread::current_park_blocker() { 2600 // Support for JSR-166 locks 2601 oop thread_oop = threadObj(); 2602 if (thread_oop != NULL && JDK_Version::supports_thread_park_blocker()) { 2603 return java_lang_Thread::park_blocker(thread_oop); 2604 } 2605 return NULL; 2606} 2607 2608 2609void JavaThread::print_stack_on(outputStream* st) { 2610 if (!has_last_Java_frame()) return; 2611 ResourceMark rm; 2612 HandleMark hm; 2613 2614 RegisterMap reg_map(this); 2615 vframe* start_vf = last_java_vframe(®_map); 2616 int count = 0; 2617 for (vframe* f = start_vf; f; f = f->sender() ) { 2618 if (f->is_java_frame()) { 2619 javaVFrame* jvf = javaVFrame::cast(f); 2620 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 2621 2622 // Print out lock information 2623 if (JavaMonitorsInStackTrace) { 2624 jvf->print_lock_info_on(st, count); 2625 } 2626 } else { 2627 // Ignore non-Java frames 2628 } 2629 2630 // Bail-out case for too deep stacks 2631 count++; 2632 if (MaxJavaStackTraceDepth == count) return; 2633 } 2634} 2635 2636 2637// JVMTI PopFrame support 2638void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 2639 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 2640 if (in_bytes(size_in_bytes) != 0) { 2641 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes)); 2642 _popframe_preserved_args_size = in_bytes(size_in_bytes); 2643 Copy::conjoint_bytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 2644 } 2645} 2646 2647void* JavaThread::popframe_preserved_args() { 2648 return _popframe_preserved_args; 2649} 2650 2651ByteSize JavaThread::popframe_preserved_args_size() { 2652 return in_ByteSize(_popframe_preserved_args_size); 2653} 2654 2655WordSize JavaThread::popframe_preserved_args_size_in_words() { 2656 int sz = in_bytes(popframe_preserved_args_size()); 2657 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 2658 return in_WordSize(sz / wordSize); 2659} 2660 2661void JavaThread::popframe_free_preserved_args() { 2662 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 2663 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 2664 _popframe_preserved_args = NULL; 2665 _popframe_preserved_args_size = 0; 2666} 2667 2668#ifndef PRODUCT 2669 2670void JavaThread::trace_frames() { 2671 tty->print_cr("[Describe stack]"); 2672 int frame_no = 1; 2673 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2674 tty->print(" %d. ", frame_no++); 2675 fst.current()->print_value_on(tty,this); 2676 tty->cr(); 2677 } 2678} 2679 2680 2681void JavaThread::trace_stack_from(vframe* start_vf) { 2682 ResourceMark rm; 2683 int vframe_no = 1; 2684 for (vframe* f = start_vf; f; f = f->sender() ) { 2685 if (f->is_java_frame()) { 2686 javaVFrame::cast(f)->print_activation(vframe_no++); 2687 } else { 2688 f->print(); 2689 } 2690 if (vframe_no > StackPrintLimit) { 2691 tty->print_cr("...<more frames>..."); 2692 return; 2693 } 2694 } 2695} 2696 2697 2698void JavaThread::trace_stack() { 2699 if (!has_last_Java_frame()) return; 2700 ResourceMark rm; 2701 HandleMark hm; 2702 RegisterMap reg_map(this); 2703 trace_stack_from(last_java_vframe(®_map)); 2704} 2705 2706 2707#endif // PRODUCT 2708 2709 2710javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 2711 assert(reg_map != NULL, "a map must be given"); 2712 frame f = last_frame(); 2713 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 2714 if (vf->is_java_frame()) return javaVFrame::cast(vf); 2715 } 2716 return NULL; 2717} 2718 2719 2720klassOop JavaThread::security_get_caller_class(int depth) { 2721 vframeStream vfst(this); 2722 vfst.security_get_caller_frame(depth); 2723 if (!vfst.at_end()) { 2724 return vfst.method()->method_holder(); 2725 } 2726 return NULL; 2727} 2728 2729static void compiler_thread_entry(JavaThread* thread, TRAPS) { 2730 assert(thread->is_Compiler_thread(), "must be compiler thread"); 2731 CompileBroker::compiler_thread_loop(); 2732} 2733 2734// Create a CompilerThread 2735CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 2736: JavaThread(&compiler_thread_entry) { 2737 _env = NULL; 2738 _log = NULL; 2739 _task = NULL; 2740 _queue = queue; 2741 _counters = counters; 2742 2743#ifndef PRODUCT 2744 _ideal_graph_printer = NULL; 2745#endif 2746} 2747 2748 2749// ======= Threads ======== 2750 2751// The Threads class links together all active threads, and provides 2752// operations over all threads. It is protected by its own Mutex 2753// lock, which is also used in other contexts to protect thread 2754// operations from having the thread being operated on from exiting 2755// and going away unexpectedly (e.g., safepoint synchronization) 2756 2757JavaThread* Threads::_thread_list = NULL; 2758int Threads::_number_of_threads = 0; 2759int Threads::_number_of_non_daemon_threads = 0; 2760int Threads::_return_code = 0; 2761size_t JavaThread::_stack_size_at_create = 0; 2762 2763// All JavaThreads 2764#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 2765 2766void os_stream(); 2767 2768// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 2769void Threads::threads_do(ThreadClosure* tc) { 2770 assert_locked_or_safepoint(Threads_lock); 2771 // ALL_JAVA_THREADS iterates through all JavaThreads 2772 ALL_JAVA_THREADS(p) { 2773 tc->do_thread(p); 2774 } 2775 // Someday we could have a table or list of all non-JavaThreads. 2776 // For now, just manually iterate through them. 2777 tc->do_thread(VMThread::vm_thread()); 2778 Universe::heap()->gc_threads_do(tc); 2779 tc->do_thread(WatcherThread::watcher_thread()); 2780 // If CompilerThreads ever become non-JavaThreads, add them here 2781} 2782 2783jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 2784 2785 // Check version 2786 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 2787 2788 // Initialize the output stream module 2789 ostream_init(); 2790 2791 // Process java launcher properties. 2792 Arguments::process_sun_java_launcher_properties(args); 2793 2794 // Initialize the os module before using TLS 2795 os::init(); 2796 2797 // Initialize system properties. 2798 Arguments::init_system_properties(); 2799 2800 // Parse arguments 2801 jint parse_result = Arguments::parse(args); 2802 if (parse_result != JNI_OK) return parse_result; 2803 2804 if (PauseAtStartup) { 2805 os::pause(); 2806 } 2807 2808 HS_DTRACE_PROBE(hotspot, vm__init__begin); 2809 2810 // Record VM creation timing statistics 2811 TraceVmCreationTime create_vm_timer; 2812 create_vm_timer.start(); 2813 2814 // Timing (must come after argument parsing) 2815 TraceTime timer("Create VM", TraceStartupTime); 2816 2817 // Initialize the os module after parsing the args 2818 jint os_init_2_result = os::init_2(); 2819 if (os_init_2_result != JNI_OK) return os_init_2_result; 2820 2821 // Initialize output stream logging 2822 ostream_init_log(); 2823 2824 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 2825 // Must be before create_vm_init_agents() 2826 if (Arguments::init_libraries_at_startup()) { 2827 convert_vm_init_libraries_to_agents(); 2828 } 2829 2830 // Launch -agentlib/-agentpath and converted -Xrun agents 2831 if (Arguments::init_agents_at_startup()) { 2832 create_vm_init_agents(); 2833 } 2834 2835 // Initialize Threads state 2836 _thread_list = NULL; 2837 _number_of_threads = 0; 2838 _number_of_non_daemon_threads = 0; 2839 2840 // Initialize TLS 2841 ThreadLocalStorage::init(); 2842 2843 // Initialize global data structures and create system classes in heap 2844 vm_init_globals(); 2845 2846 // Attach the main thread to this os thread 2847 JavaThread* main_thread = new JavaThread(); 2848 main_thread->set_thread_state(_thread_in_vm); 2849 // must do this before set_active_handles and initialize_thread_local_storage 2850 // Note: on solaris initialize_thread_local_storage() will (indirectly) 2851 // change the stack size recorded here to one based on the java thread 2852 // stacksize. This adjusted size is what is used to figure the placement 2853 // of the guard pages. 2854 main_thread->record_stack_base_and_size(); 2855 main_thread->initialize_thread_local_storage(); 2856 2857 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 2858 2859 if (!main_thread->set_as_starting_thread()) { 2860 vm_shutdown_during_initialization( 2861 "Failed necessary internal allocation. Out of swap space"); 2862 delete main_thread; 2863 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 2864 return JNI_ENOMEM; 2865 } 2866 2867 // Enable guard page *after* os::create_main_thread(), otherwise it would 2868 // crash Linux VM, see notes in os_linux.cpp. 2869 main_thread->create_stack_guard_pages(); 2870 2871 // Initialize Java-Leve synchronization subsystem 2872 ObjectSynchronizer::Initialize() ; 2873 2874 // Initialize global modules 2875 jint status = init_globals(); 2876 if (status != JNI_OK) { 2877 delete main_thread; 2878 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 2879 return status; 2880 } 2881 2882 HandleMark hm; 2883 2884 { MutexLocker mu(Threads_lock); 2885 Threads::add(main_thread); 2886 } 2887 2888 // Any JVMTI raw monitors entered in onload will transition into 2889 // real raw monitor. VM is setup enough here for raw monitor enter. 2890 JvmtiExport::transition_pending_onload_raw_monitors(); 2891 2892 if (VerifyBeforeGC && 2893 Universe::heap()->total_collections() >= VerifyGCStartAt) { 2894 Universe::heap()->prepare_for_verify(); 2895 Universe::verify(); // make sure we're starting with a clean slate 2896 } 2897 2898 // Create the VMThread 2899 { TraceTime timer("Start VMThread", TraceStartupTime); 2900 VMThread::create(); 2901 Thread* vmthread = VMThread::vm_thread(); 2902 2903 if (!os::create_thread(vmthread, os::vm_thread)) 2904 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 2905 2906 // Wait for the VM thread to become ready, and VMThread::run to initialize 2907 // Monitors can have spurious returns, must always check another state flag 2908 { 2909 MutexLocker ml(Notify_lock); 2910 os::start_thread(vmthread); 2911 while (vmthread->active_handles() == NULL) { 2912 Notify_lock->wait(); 2913 } 2914 } 2915 } 2916 2917 assert (Universe::is_fully_initialized(), "not initialized"); 2918 EXCEPTION_MARK; 2919 2920 // At this point, the Universe is initialized, but we have not executed 2921 // any byte code. Now is a good time (the only time) to dump out the 2922 // internal state of the JVM for sharing. 2923 2924 if (DumpSharedSpaces) { 2925 Universe::heap()->preload_and_dump(CHECK_0); 2926 ShouldNotReachHere(); 2927 } 2928 2929 // Always call even when there are not JVMTI environments yet, since environments 2930 // may be attached late and JVMTI must track phases of VM execution 2931 JvmtiExport::enter_start_phase(); 2932 2933 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 2934 JvmtiExport::post_vm_start(); 2935 2936 { 2937 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 2938 2939 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 2940 create_vm_init_libraries(); 2941 } 2942 2943 if (InitializeJavaLangString) { 2944 initialize_class(vmSymbolHandles::java_lang_String(), CHECK_0); 2945 } else { 2946 warning("java.lang.String not initialized"); 2947 } 2948 2949 if (AggressiveOpts) { 2950 // Forcibly initialize java/util/HashMap and mutate the private 2951 // static final "frontCacheEnabled" field before we start creating instances 2952#ifdef ASSERT 2953 klassOop tmp_k = SystemDictionary::find(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0); 2954 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 2955#endif 2956 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0); 2957 KlassHandle k = KlassHandle(THREAD, k_o); 2958 guarantee(k.not_null(), "Must find java/util/HashMap"); 2959 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 2960 ik->initialize(CHECK_0); 2961 fieldDescriptor fd; 2962 // Possible we might not find this field; if so, don't break 2963 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 2964 k()->bool_field_put(fd.offset(), true); 2965 } 2966 } 2967 2968 // Initialize java_lang.System (needed before creating the thread) 2969 if (InitializeJavaLangSystem) { 2970 initialize_class(vmSymbolHandles::java_lang_System(), CHECK_0); 2971 initialize_class(vmSymbolHandles::java_lang_ThreadGroup(), CHECK_0); 2972 Handle thread_group = create_initial_thread_group(CHECK_0); 2973 Universe::set_main_thread_group(thread_group()); 2974 initialize_class(vmSymbolHandles::java_lang_Thread(), CHECK_0); 2975 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 2976 main_thread->set_threadObj(thread_object); 2977 // Set thread status to running since main thread has 2978 // been started and running. 2979 java_lang_Thread::set_thread_status(thread_object, 2980 java_lang_Thread::RUNNABLE); 2981 2982 // The VM preresolve methods to these classes. Make sure that get initialized 2983 initialize_class(vmSymbolHandles::java_lang_reflect_Method(), CHECK_0); 2984 initialize_class(vmSymbolHandles::java_lang_ref_Finalizer(), CHECK_0); 2985 // The VM creates & returns objects of this class. Make sure it's initialized. 2986 initialize_class(vmSymbolHandles::java_lang_Class(), CHECK_0); 2987 call_initializeSystemClass(CHECK_0); 2988 } else { 2989 warning("java.lang.System not initialized"); 2990 } 2991 2992 // an instance of OutOfMemory exception has been allocated earlier 2993 if (InitializeJavaLangExceptionsErrors) { 2994 initialize_class(vmSymbolHandles::java_lang_OutOfMemoryError(), CHECK_0); 2995 initialize_class(vmSymbolHandles::java_lang_NullPointerException(), CHECK_0); 2996 initialize_class(vmSymbolHandles::java_lang_ClassCastException(), CHECK_0); 2997 initialize_class(vmSymbolHandles::java_lang_ArrayStoreException(), CHECK_0); 2998 initialize_class(vmSymbolHandles::java_lang_ArithmeticException(), CHECK_0); 2999 initialize_class(vmSymbolHandles::java_lang_StackOverflowError(), CHECK_0); 3000 initialize_class(vmSymbolHandles::java_lang_IllegalMonitorStateException(), CHECK_0); 3001 } else { 3002 warning("java.lang.OutOfMemoryError has not been initialized"); 3003 warning("java.lang.NullPointerException has not been initialized"); 3004 warning("java.lang.ClassCastException has not been initialized"); 3005 warning("java.lang.ArrayStoreException has not been initialized"); 3006 warning("java.lang.ArithmeticException has not been initialized"); 3007 warning("java.lang.StackOverflowError has not been initialized"); 3008 } 3009 } 3010 3011 // See : bugid 4211085. 3012 // Background : the static initializer of java.lang.Compiler tries to read 3013 // property"java.compiler" and read & write property "java.vm.info". 3014 // When a security manager is installed through the command line 3015 // option "-Djava.security.manager", the above properties are not 3016 // readable and the static initializer for java.lang.Compiler fails 3017 // resulting in a NoClassDefFoundError. This can happen in any 3018 // user code which calls methods in java.lang.Compiler. 3019 // Hack : the hack is to pre-load and initialize this class, so that only 3020 // system domains are on the stack when the properties are read. 3021 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3022 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3023 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3024 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3025 // Once that is done, we should remove this hack. 3026 initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0); 3027 3028 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3029 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3030 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3031 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3032 // This should also be taken out as soon as 4211383 gets fixed. 3033 reset_vm_info_property(CHECK_0); 3034 3035 quicken_jni_functions(); 3036 3037 // Set flag that basic initialization has completed. Used by exceptions and various 3038 // debug stuff, that does not work until all basic classes have been initialized. 3039 set_init_completed(); 3040 3041 HS_DTRACE_PROBE(hotspot, vm__init__end); 3042 3043 // record VM initialization completion time 3044 Management::record_vm_init_completed(); 3045 3046 // Compute system loader. Note that this has to occur after set_init_completed, since 3047 // valid exceptions may be thrown in the process. 3048 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3049 // set_init_completed has just been called, causing exceptions not to be shortcut 3050 // anymore. We call vm_exit_during_initialization directly instead. 3051 SystemDictionary::compute_java_system_loader(THREAD); 3052 if (HAS_PENDING_EXCEPTION) { 3053 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3054 } 3055 3056#ifndef SERIALGC 3057 // Support for ConcurrentMarkSweep. This should be cleaned up 3058 // and better encapsulated. The ugly nested if test would go away 3059 // once things are properly refactored. XXX YSR 3060 if (UseConcMarkSweepGC || UseG1GC) { 3061 if (UseConcMarkSweepGC) { 3062 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3063 } else { 3064 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3065 } 3066 if (HAS_PENDING_EXCEPTION) { 3067 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3068 } 3069 } 3070#endif // SERIALGC 3071 3072 // Always call even when there are not JVMTI environments yet, since environments 3073 // may be attached late and JVMTI must track phases of VM execution 3074 JvmtiExport::enter_live_phase(); 3075 3076 // Signal Dispatcher needs to be started before VMInit event is posted 3077 os::signal_init(); 3078 3079 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3080 if (!DisableAttachMechanism) { 3081 if (StartAttachListener || AttachListener::init_at_startup()) { 3082 AttachListener::init(); 3083 } 3084 } 3085 3086 // Launch -Xrun agents 3087 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3088 // back-end can launch with -Xdebug -Xrunjdwp. 3089 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3090 create_vm_init_libraries(); 3091 } 3092 3093 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3094 JvmtiExport::post_vm_initialized(); 3095 3096 Chunk::start_chunk_pool_cleaner_task(); 3097 3098 // initialize compiler(s) 3099 CompileBroker::compilation_init(); 3100 3101 Management::initialize(THREAD); 3102 if (HAS_PENDING_EXCEPTION) { 3103 // management agent fails to start possibly due to 3104 // configuration problem and is responsible for printing 3105 // stack trace if appropriate. Simply exit VM. 3106 vm_exit(1); 3107 } 3108 3109 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3110 if (Arguments::has_alloc_profile()) AllocationProfiler::engage(); 3111 if (MemProfiling) MemProfiler::engage(); 3112 StatSampler::engage(); 3113 if (CheckJNICalls) JniPeriodicChecker::engage(); 3114 3115 BiasedLocking::init(); 3116 3117 3118 // Start up the WatcherThread if there are any periodic tasks 3119 // NOTE: All PeriodicTasks should be registered by now. If they 3120 // aren't, late joiners might appear to start slowly (we might 3121 // take a while to process their first tick). 3122 if (PeriodicTask::num_tasks() > 0) { 3123 WatcherThread::start(); 3124 } 3125 3126 create_vm_timer.end(); 3127 return JNI_OK; 3128} 3129 3130// type for the Agent_OnLoad and JVM_OnLoad entry points 3131extern "C" { 3132 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3133} 3134// Find a command line agent library and return its entry point for 3135// -agentlib: -agentpath: -Xrun 3136// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3137static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3138 OnLoadEntry_t on_load_entry = NULL; 3139 void *library = agent->os_lib(); // check if we have looked it up before 3140 3141 if (library == NULL) { 3142 char buffer[JVM_MAXPATHLEN]; 3143 char ebuf[1024]; 3144 const char *name = agent->name(); 3145 3146 if (agent->is_absolute_path()) { 3147 library = hpi::dll_load(name, ebuf, sizeof ebuf); 3148 if (library == NULL) { 3149 // If we can't find the agent, exit. 3150 vm_exit_during_initialization("Could not find agent library in absolute path", name); 3151 } 3152 } else { 3153 // Try to load the agent from the standard dll directory 3154 hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name); 3155 library = hpi::dll_load(buffer, ebuf, sizeof ebuf); 3156#ifdef KERNEL 3157 // Download instrument dll 3158 if (library == NULL && strcmp(name, "instrument") == 0) { 3159 char *props = Arguments::get_kernel_properties(); 3160 char *home = Arguments::get_java_home(); 3161 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false" 3162 " sun.jkernel.DownloadManager -download client_jvm"; 3163 int length = strlen(props) + strlen(home) + strlen(fmt) + 1; 3164 char *cmd = AllocateHeap(length); 3165 jio_snprintf(cmd, length, fmt, home, props); 3166 int status = os::fork_and_exec(cmd); 3167 FreeHeap(props); 3168 FreeHeap(cmd); 3169 if (status == -1) { 3170 warning(cmd); 3171 vm_exit_during_initialization("fork_and_exec failed: %s", 3172 strerror(errno)); 3173 } 3174 // when this comes back the instrument.dll should be where it belongs. 3175 library = hpi::dll_load(buffer, ebuf, sizeof ebuf); 3176 } 3177#endif // KERNEL 3178 if (library == NULL) { // Try the local directory 3179 char ns[1] = {0}; 3180 hpi::dll_build_name(buffer, sizeof(buffer), ns, name); 3181 library = hpi::dll_load(buffer, ebuf, sizeof ebuf); 3182 if (library == NULL) { 3183 // If we can't find the agent, exit. 3184 vm_exit_during_initialization("Could not find agent library on the library path or in the local directory", name); 3185 } 3186 } 3187 } 3188 agent->set_os_lib(library); 3189 } 3190 3191 // Find the OnLoad function. 3192 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3193 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, hpi::dll_lookup(library, on_load_symbols[symbol_index])); 3194 if (on_load_entry != NULL) break; 3195 } 3196 return on_load_entry; 3197} 3198 3199// Find the JVM_OnLoad entry point 3200static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3201 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3202 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3203} 3204 3205// Find the Agent_OnLoad entry point 3206static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3207 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3208 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3209} 3210 3211// For backwards compatibility with -Xrun 3212// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3213// treated like -agentpath: 3214// Must be called before agent libraries are created 3215void Threads::convert_vm_init_libraries_to_agents() { 3216 AgentLibrary* agent; 3217 AgentLibrary* next; 3218 3219 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3220 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3221 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3222 3223 // If there is an JVM_OnLoad function it will get called later, 3224 // otherwise see if there is an Agent_OnLoad 3225 if (on_load_entry == NULL) { 3226 on_load_entry = lookup_agent_on_load(agent); 3227 if (on_load_entry != NULL) { 3228 // switch it to the agent list -- so that Agent_OnLoad will be called, 3229 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3230 Arguments::convert_library_to_agent(agent); 3231 } else { 3232 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3233 } 3234 } 3235 } 3236} 3237 3238// Create agents for -agentlib: -agentpath: and converted -Xrun 3239// Invokes Agent_OnLoad 3240// Called very early -- before JavaThreads exist 3241void Threads::create_vm_init_agents() { 3242 extern struct JavaVM_ main_vm; 3243 AgentLibrary* agent; 3244 3245 JvmtiExport::enter_onload_phase(); 3246 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3247 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3248 3249 if (on_load_entry != NULL) { 3250 // Invoke the Agent_OnLoad function 3251 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3252 if (err != JNI_OK) { 3253 vm_exit_during_initialization("agent library failed to init", agent->name()); 3254 } 3255 } else { 3256 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3257 } 3258 } 3259 JvmtiExport::enter_primordial_phase(); 3260} 3261 3262extern "C" { 3263 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3264} 3265 3266void Threads::shutdown_vm_agents() { 3267 // Send any Agent_OnUnload notifications 3268 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3269 extern struct JavaVM_ main_vm; 3270 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3271 3272 // Find the Agent_OnUnload function. 3273 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3274 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3275 hpi::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3276 3277 // Invoke the Agent_OnUnload function 3278 if (unload_entry != NULL) { 3279 JavaThread* thread = JavaThread::current(); 3280 ThreadToNativeFromVM ttn(thread); 3281 HandleMark hm(thread); 3282 (*unload_entry)(&main_vm); 3283 break; 3284 } 3285 } 3286 } 3287} 3288 3289// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3290// Invokes JVM_OnLoad 3291void Threads::create_vm_init_libraries() { 3292 extern struct JavaVM_ main_vm; 3293 AgentLibrary* agent; 3294 3295 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3296 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3297 3298 if (on_load_entry != NULL) { 3299 // Invoke the JVM_OnLoad function 3300 JavaThread* thread = JavaThread::current(); 3301 ThreadToNativeFromVM ttn(thread); 3302 HandleMark hm(thread); 3303 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3304 if (err != JNI_OK) { 3305 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3306 } 3307 } else { 3308 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3309 } 3310 } 3311} 3312 3313// Last thread running calls java.lang.Shutdown.shutdown() 3314void JavaThread::invoke_shutdown_hooks() { 3315 HandleMark hm(this); 3316 3317 // We could get here with a pending exception, if so clear it now. 3318 if (this->has_pending_exception()) { 3319 this->clear_pending_exception(); 3320 } 3321 3322 EXCEPTION_MARK; 3323 klassOop k = 3324 SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_Shutdown(), 3325 THREAD); 3326 if (k != NULL) { 3327 // SystemDictionary::resolve_or_null will return null if there was 3328 // an exception. If we cannot load the Shutdown class, just don't 3329 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3330 // and finalizers (if runFinalizersOnExit is set) won't be run. 3331 // Note that if a shutdown hook was registered or runFinalizersOnExit 3332 // was called, the Shutdown class would have already been loaded 3333 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3334 instanceKlassHandle shutdown_klass (THREAD, k); 3335 JavaValue result(T_VOID); 3336 JavaCalls::call_static(&result, 3337 shutdown_klass, 3338 vmSymbolHandles::shutdown_method_name(), 3339 vmSymbolHandles::void_method_signature(), 3340 THREAD); 3341 } 3342 CLEAR_PENDING_EXCEPTION; 3343} 3344 3345// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3346// the program falls off the end of main(). Another VM exit path is through 3347// vm_exit() when the program calls System.exit() to return a value or when 3348// there is a serious error in VM. The two shutdown paths are not exactly 3349// the same, but they share Shutdown.shutdown() at Java level and before_exit() 3350// and VM_Exit op at VM level. 3351// 3352// Shutdown sequence: 3353// + Wait until we are the last non-daemon thread to execute 3354// <-- every thing is still working at this moment --> 3355// + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3356// shutdown hooks, run finalizers if finalization-on-exit 3357// + Call before_exit(), prepare for VM exit 3358// > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3359// currently the only user of this mechanism is File.deleteOnExit()) 3360// > stop flat profiler, StatSampler, watcher thread, CMS threads, 3361// post thread end and vm death events to JVMTI, 3362// stop signal thread 3363// + Call JavaThread::exit(), it will: 3364// > release JNI handle blocks, remove stack guard pages 3365// > remove this thread from Threads list 3366// <-- no more Java code from this thread after this point --> 3367// + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3368// the compiler threads at safepoint 3369// <-- do not use anything that could get blocked by Safepoint --> 3370// + Disable tracing at JNI/JVM barriers 3371// + Set _vm_exited flag for threads that are still running native code 3372// + Delete this thread 3373// + Call exit_globals() 3374// > deletes tty 3375// > deletes PerfMemory resources 3376// + Return to caller 3377 3378bool Threads::destroy_vm() { 3379 JavaThread* thread = JavaThread::current(); 3380 3381 // Wait until we are the last non-daemon thread to execute 3382 { MutexLocker nu(Threads_lock); 3383 while (Threads::number_of_non_daemon_threads() > 1 ) 3384 // This wait should make safepoint checks, wait without a timeout, 3385 // and wait as a suspend-equivalent condition. 3386 // 3387 // Note: If the FlatProfiler is running and this thread is waiting 3388 // for another non-daemon thread to finish, then the FlatProfiler 3389 // is waiting for the external suspend request on this thread to 3390 // complete. wait_for_ext_suspend_completion() will eventually 3391 // timeout, but that takes time. Making this wait a suspend- 3392 // equivalent condition solves that timeout problem. 3393 // 3394 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3395 Mutex::_as_suspend_equivalent_flag); 3396 } 3397 3398 // Hang forever on exit if we are reporting an error. 3399 if (ShowMessageBoxOnError && is_error_reported()) { 3400 os::infinite_sleep(); 3401 } 3402 3403 if (JDK_Version::is_jdk12x_version()) { 3404 // We are the last thread running, so check if finalizers should be run. 3405 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3406 HandleMark rm(thread); 3407 Universe::run_finalizers_on_exit(); 3408 } else { 3409 // run Java level shutdown hooks 3410 thread->invoke_shutdown_hooks(); 3411 } 3412 3413 before_exit(thread); 3414 3415 thread->exit(true); 3416 3417 // Stop VM thread. 3418 { 3419 // 4945125 The vm thread comes to a safepoint during exit. 3420 // GC vm_operations can get caught at the safepoint, and the 3421 // heap is unparseable if they are caught. Grab the Heap_lock 3422 // to prevent this. The GC vm_operations will not be able to 3423 // queue until after the vm thread is dead. 3424 MutexLocker ml(Heap_lock); 3425 3426 VMThread::wait_for_vm_thread_exit(); 3427 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3428 VMThread::destroy(); 3429 } 3430 3431 // clean up ideal graph printers 3432#if defined(COMPILER2) && !defined(PRODUCT) 3433 IdealGraphPrinter::clean_up(); 3434#endif 3435 3436 // Now, all Java threads are gone except daemon threads. Daemon threads 3437 // running Java code or in VM are stopped by the Safepoint. However, 3438 // daemon threads executing native code are still running. But they 3439 // will be stopped at native=>Java/VM barriers. Note that we can't 3440 // simply kill or suspend them, as it is inherently deadlock-prone. 3441 3442#ifndef PRODUCT 3443 // disable function tracing at JNI/JVM barriers 3444 TraceHPI = false; 3445 TraceJNICalls = false; 3446 TraceJVMCalls = false; 3447 TraceRuntimeCalls = false; 3448#endif 3449 3450 VM_Exit::set_vm_exited(); 3451 3452 notify_vm_shutdown(); 3453 3454 delete thread; 3455 3456 // exit_globals() will delete tty 3457 exit_globals(); 3458 3459 return true; 3460} 3461 3462 3463jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 3464 if (version == JNI_VERSION_1_1) return JNI_TRUE; 3465 return is_supported_jni_version(version); 3466} 3467 3468 3469jboolean Threads::is_supported_jni_version(jint version) { 3470 if (version == JNI_VERSION_1_2) return JNI_TRUE; 3471 if (version == JNI_VERSION_1_4) return JNI_TRUE; 3472 if (version == JNI_VERSION_1_6) return JNI_TRUE; 3473 return JNI_FALSE; 3474} 3475 3476 3477void Threads::add(JavaThread* p, bool force_daemon) { 3478 // The threads lock must be owned at this point 3479 assert_locked_or_safepoint(Threads_lock); 3480 p->set_next(_thread_list); 3481 _thread_list = p; 3482 _number_of_threads++; 3483 oop threadObj = p->threadObj(); 3484 bool daemon = true; 3485 // Bootstrapping problem: threadObj can be null for initial 3486 // JavaThread (or for threads attached via JNI) 3487 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 3488 _number_of_non_daemon_threads++; 3489 daemon = false; 3490 } 3491 3492 ThreadService::add_thread(p, daemon); 3493 3494 // Possible GC point. 3495 Events::log("Thread added: " INTPTR_FORMAT, p); 3496} 3497 3498void Threads::remove(JavaThread* p) { 3499 // Extra scope needed for Thread_lock, so we can check 3500 // that we do not remove thread without safepoint code notice 3501 { MutexLocker ml(Threads_lock); 3502 3503 assert(includes(p), "p must be present"); 3504 3505 JavaThread* current = _thread_list; 3506 JavaThread* prev = NULL; 3507 3508 while (current != p) { 3509 prev = current; 3510 current = current->next(); 3511 } 3512 3513 if (prev) { 3514 prev->set_next(current->next()); 3515 } else { 3516 _thread_list = p->next(); 3517 } 3518 _number_of_threads--; 3519 oop threadObj = p->threadObj(); 3520 bool daemon = true; 3521 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 3522 _number_of_non_daemon_threads--; 3523 daemon = false; 3524 3525 // Only one thread left, do a notify on the Threads_lock so a thread waiting 3526 // on destroy_vm will wake up. 3527 if (number_of_non_daemon_threads() == 1) 3528 Threads_lock->notify_all(); 3529 } 3530 ThreadService::remove_thread(p, daemon); 3531 3532 // Make sure that safepoint code disregard this thread. This is needed since 3533 // the thread might mess around with locks after this point. This can cause it 3534 // to do callbacks into the safepoint code. However, the safepoint code is not aware 3535 // of this thread since it is removed from the queue. 3536 p->set_terminated_value(); 3537 } // unlock Threads_lock 3538 3539 // Since Events::log uses a lock, we grab it outside the Threads_lock 3540 Events::log("Thread exited: " INTPTR_FORMAT, p); 3541} 3542 3543// Threads_lock must be held when this is called (or must be called during a safepoint) 3544bool Threads::includes(JavaThread* p) { 3545 assert(Threads_lock->is_locked(), "sanity check"); 3546 ALL_JAVA_THREADS(q) { 3547 if (q == p ) { 3548 return true; 3549 } 3550 } 3551 return false; 3552} 3553 3554// Operations on the Threads list for GC. These are not explicitly locked, 3555// but the garbage collector must provide a safe context for them to run. 3556// In particular, these things should never be called when the Threads_lock 3557// is held by some other thread. (Note: the Safepoint abstraction also 3558// uses the Threads_lock to gurantee this property. It also makes sure that 3559// all threads gets blocked when exiting or starting). 3560 3561void Threads::oops_do(OopClosure* f) { 3562 ALL_JAVA_THREADS(p) { 3563 p->oops_do(f); 3564 } 3565 VMThread::vm_thread()->oops_do(f); 3566} 3567 3568void Threads::possibly_parallel_oops_do(OopClosure* f) { 3569 // Introduce a mechanism allowing parallel threads to claim threads as 3570 // root groups. Overhead should be small enough to use all the time, 3571 // even in sequential code. 3572 SharedHeap* sh = SharedHeap::heap(); 3573 bool is_par = (sh->n_par_threads() > 0); 3574 int cp = SharedHeap::heap()->strong_roots_parity(); 3575 ALL_JAVA_THREADS(p) { 3576 if (p->claim_oops_do(is_par, cp)) { 3577 p->oops_do(f); 3578 } 3579 } 3580 VMThread* vmt = VMThread::vm_thread(); 3581 if (vmt->claim_oops_do(is_par, cp)) 3582 vmt->oops_do(f); 3583} 3584 3585#ifndef SERIALGC 3586// Used by ParallelScavenge 3587void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 3588 ALL_JAVA_THREADS(p) { 3589 q->enqueue(new ThreadRootsTask(p)); 3590 } 3591 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 3592} 3593 3594// Used by Parallel Old 3595void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 3596 ALL_JAVA_THREADS(p) { 3597 q->enqueue(new ThreadRootsMarkingTask(p)); 3598 } 3599 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 3600} 3601#endif // SERIALGC 3602 3603void Threads::nmethods_do() { 3604 ALL_JAVA_THREADS(p) { 3605 p->nmethods_do(); 3606 } 3607 VMThread::vm_thread()->nmethods_do(); 3608} 3609 3610void Threads::gc_epilogue() { 3611 ALL_JAVA_THREADS(p) { 3612 p->gc_epilogue(); 3613 } 3614} 3615 3616void Threads::gc_prologue() { 3617 ALL_JAVA_THREADS(p) { 3618 p->gc_prologue(); 3619 } 3620} 3621 3622void Threads::deoptimized_wrt_marked_nmethods() { 3623 ALL_JAVA_THREADS(p) { 3624 p->deoptimized_wrt_marked_nmethods(); 3625 } 3626} 3627 3628 3629// Get count Java threads that are waiting to enter the specified monitor. 3630GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 3631 address monitor, bool doLock) { 3632 assert(doLock || SafepointSynchronize::is_at_safepoint(), 3633 "must grab Threads_lock or be at safepoint"); 3634 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 3635 3636 int i = 0; 3637 { 3638 MutexLockerEx ml(doLock ? Threads_lock : NULL); 3639 ALL_JAVA_THREADS(p) { 3640 if (p->is_Compiler_thread()) continue; 3641 3642 address pending = (address)p->current_pending_monitor(); 3643 if (pending == monitor) { // found a match 3644 if (i < count) result->append(p); // save the first count matches 3645 i++; 3646 } 3647 } 3648 } 3649 return result; 3650} 3651 3652 3653JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 3654 assert(doLock || 3655 Threads_lock->owned_by_self() || 3656 SafepointSynchronize::is_at_safepoint(), 3657 "must grab Threads_lock or be at safepoint"); 3658 3659 // NULL owner means not locked so we can skip the search 3660 if (owner == NULL) return NULL; 3661 3662 { 3663 MutexLockerEx ml(doLock ? Threads_lock : NULL); 3664 ALL_JAVA_THREADS(p) { 3665 // first, see if owner is the address of a Java thread 3666 if (owner == (address)p) return p; 3667 } 3668 } 3669 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled"); 3670 if (UseHeavyMonitors) return NULL; 3671 3672 // 3673 // If we didn't find a matching Java thread and we didn't force use of 3674 // heavyweight monitors, then the owner is the stack address of the 3675 // Lock Word in the owning Java thread's stack. 3676 // 3677 // We can't use Thread::is_lock_owned() or Thread::lock_is_in_stack() because 3678 // those routines rely on the "current" stack pointer. That would be our 3679 // stack pointer which is not relevant to the question. Instead we use the 3680 // highest lock ever entered by the thread and find the thread that is 3681 // higher than and closest to our target stack address. 3682 // 3683 address least_diff = 0; 3684 bool least_diff_initialized = false; 3685 JavaThread* the_owner = NULL; 3686 { 3687 MutexLockerEx ml(doLock ? Threads_lock : NULL); 3688 ALL_JAVA_THREADS(q) { 3689 address addr = q->highest_lock(); 3690 if (addr == NULL || addr < owner) continue; // thread has entered no monitors or is too low 3691 address diff = (address)(addr - owner); 3692 if (!least_diff_initialized || diff < least_diff) { 3693 least_diff_initialized = true; 3694 least_diff = diff; 3695 the_owner = q; 3696 } 3697 } 3698 } 3699 assert(the_owner != NULL, "Did not find owning Java thread for lock word address"); 3700 return the_owner; 3701} 3702 3703// Threads::print_on() is called at safepoint by VM_PrintThreads operation. 3704void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 3705 char buf[32]; 3706 st->print_cr(os::local_time_string(buf, sizeof(buf))); 3707 3708 st->print_cr("Full thread dump %s (%s %s):", 3709 Abstract_VM_Version::vm_name(), 3710 Abstract_VM_Version::vm_release(), 3711 Abstract_VM_Version::vm_info_string() 3712 ); 3713 st->cr(); 3714 3715#ifndef SERIALGC 3716 // Dump concurrent locks 3717 ConcurrentLocksDump concurrent_locks; 3718 if (print_concurrent_locks) { 3719 concurrent_locks.dump_at_safepoint(); 3720 } 3721#endif // SERIALGC 3722 3723 ALL_JAVA_THREADS(p) { 3724 ResourceMark rm; 3725 p->print_on(st); 3726 if (print_stacks) { 3727 if (internal_format) { 3728 p->trace_stack(); 3729 } else { 3730 p->print_stack_on(st); 3731 } 3732 } 3733 st->cr(); 3734#ifndef SERIALGC 3735 if (print_concurrent_locks) { 3736 concurrent_locks.print_locks_on(p, st); 3737 } 3738#endif // SERIALGC 3739 } 3740 3741 VMThread::vm_thread()->print_on(st); 3742 st->cr(); 3743 Universe::heap()->print_gc_threads_on(st); 3744 WatcherThread* wt = WatcherThread::watcher_thread(); 3745 if (wt != NULL) wt->print_on(st); 3746 st->cr(); 3747 CompileBroker::print_compiler_threads_on(st); 3748 st->flush(); 3749} 3750 3751// Threads::print_on_error() is called by fatal error handler. It's possible 3752// that VM is not at safepoint and/or current thread is inside signal handler. 3753// Don't print stack trace, as the stack may not be walkable. Don't allocate 3754// memory (even in resource area), it might deadlock the error handler. 3755void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 3756 bool found_current = false; 3757 st->print_cr("Java Threads: ( => current thread )"); 3758 ALL_JAVA_THREADS(thread) { 3759 bool is_current = (current == thread); 3760 found_current = found_current || is_current; 3761 3762 st->print("%s", is_current ? "=>" : " "); 3763 3764 st->print(PTR_FORMAT, thread); 3765 st->print(" "); 3766 thread->print_on_error(st, buf, buflen); 3767 st->cr(); 3768 } 3769 st->cr(); 3770 3771 st->print_cr("Other Threads:"); 3772 if (VMThread::vm_thread()) { 3773 bool is_current = (current == VMThread::vm_thread()); 3774 found_current = found_current || is_current; 3775 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 3776 3777 st->print(PTR_FORMAT, VMThread::vm_thread()); 3778 st->print(" "); 3779 VMThread::vm_thread()->print_on_error(st, buf, buflen); 3780 st->cr(); 3781 } 3782 WatcherThread* wt = WatcherThread::watcher_thread(); 3783 if (wt != NULL) { 3784 bool is_current = (current == wt); 3785 found_current = found_current || is_current; 3786 st->print("%s", is_current ? "=>" : " "); 3787 3788 st->print(PTR_FORMAT, wt); 3789 st->print(" "); 3790 wt->print_on_error(st, buf, buflen); 3791 st->cr(); 3792 } 3793 if (!found_current) { 3794 st->cr(); 3795 st->print("=>" PTR_FORMAT " (exited) ", current); 3796 current->print_on_error(st, buf, buflen); 3797 st->cr(); 3798 } 3799} 3800 3801 3802// Lifecycle management for TSM ParkEvents. 3803// ParkEvents are type-stable (TSM). 3804// In our particular implementation they happen to be immortal. 3805// 3806// We manage concurrency on the FreeList with a CAS-based 3807// detach-modify-reattach idiom that avoids the ABA problems 3808// that would otherwise be present in a simple CAS-based 3809// push-pop implementation. (push-one and pop-all) 3810// 3811// Caveat: Allocate() and Release() may be called from threads 3812// other than the thread associated with the Event! 3813// If we need to call Allocate() when running as the thread in 3814// question then look for the PD calls to initialize native TLS. 3815// Native TLS (Win32/Linux/Solaris) can only be initialized or 3816// accessed by the associated thread. 3817// See also pd_initialize(). 3818// 3819// Note that we could defer associating a ParkEvent with a thread 3820// until the 1st time the thread calls park(). unpark() calls to 3821// an unprovisioned thread would be ignored. The first park() call 3822// for a thread would allocate and associate a ParkEvent and return 3823// immediately. 3824 3825volatile int ParkEvent::ListLock = 0 ; 3826ParkEvent * volatile ParkEvent::FreeList = NULL ; 3827 3828ParkEvent * ParkEvent::Allocate (Thread * t) { 3829 // In rare cases -- JVM_RawMonitor* operations -- we can find t == null. 3830 ParkEvent * ev ; 3831 3832 // Start by trying to recycle an existing but unassociated 3833 // ParkEvent from the global free list. 3834 for (;;) { 3835 ev = FreeList ; 3836 if (ev == NULL) break ; 3837 // 1: Detach - sequester or privatize the list 3838 // Tantamount to ev = Swap (&FreeList, NULL) 3839 if (Atomic::cmpxchg_ptr (NULL, &FreeList, ev) != ev) { 3840 continue ; 3841 } 3842 3843 // We've detached the list. The list in-hand is now 3844 // local to this thread. This thread can operate on the 3845 // list without risk of interference from other threads. 3846 // 2: Extract -- pop the 1st element from the list. 3847 ParkEvent * List = ev->FreeNext ; 3848 if (List == NULL) break ; 3849 for (;;) { 3850 // 3: Try to reattach the residual list 3851 guarantee (List != NULL, "invariant") ; 3852 ParkEvent * Arv = (ParkEvent *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ; 3853 if (Arv == NULL) break ; 3854 3855 // New nodes arrived. Try to detach the recent arrivals. 3856 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) { 3857 continue ; 3858 } 3859 guarantee (Arv != NULL, "invariant") ; 3860 // 4: Merge Arv into List 3861 ParkEvent * Tail = List ; 3862 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ; 3863 Tail->FreeNext = Arv ; 3864 } 3865 break ; 3866 } 3867 3868 if (ev != NULL) { 3869 guarantee (ev->AssociatedWith == NULL, "invariant") ; 3870 } else { 3871 // Do this the hard way -- materialize a new ParkEvent. 3872 // In rare cases an allocating thread might detach a long list -- 3873 // installing null into FreeList -- and then stall or be obstructed. 3874 // A 2nd thread calling Allocate() would see FreeList == null. 3875 // The list held privately by the 1st thread is unavailable to the 2nd thread. 3876 // In that case the 2nd thread would have to materialize a new ParkEvent, 3877 // even though free ParkEvents existed in the system. In this case we end up 3878 // with more ParkEvents in circulation than we need, but the race is 3879 // rare and the outcome is benign. Ideally, the # of extant ParkEvents 3880 // is equal to the maximum # of threads that existed at any one time. 3881 // Because of the race mentioned above, segments of the freelist 3882 // can be transiently inaccessible. At worst we may end up with the 3883 // # of ParkEvents in circulation slightly above the ideal. 3884 // Note that if we didn't have the TSM/immortal constraint, then 3885 // when reattaching, above, we could trim the list. 3886 ev = new ParkEvent () ; 3887 guarantee ((intptr_t(ev) & 0xFF) == 0, "invariant") ; 3888 } 3889 ev->reset() ; // courtesy to caller 3890 ev->AssociatedWith = t ; // Associate ev with t 3891 ev->FreeNext = NULL ; 3892 return ev ; 3893} 3894 3895void ParkEvent::Release (ParkEvent * ev) { 3896 if (ev == NULL) return ; 3897 guarantee (ev->FreeNext == NULL , "invariant") ; 3898 ev->AssociatedWith = NULL ; 3899 for (;;) { 3900 // Push ev onto FreeList 3901 // The mechanism is "half" lock-free. 3902 ParkEvent * List = FreeList ; 3903 ev->FreeNext = List ; 3904 if (Atomic::cmpxchg_ptr (ev, &FreeList, List) == List) break ; 3905 } 3906} 3907 3908// Override operator new and delete so we can ensure that the 3909// least significant byte of ParkEvent addresses is 0. 3910// Beware that excessive address alignment is undesirable 3911// as it can result in D$ index usage imbalance as 3912// well as bank access imbalance on Niagara-like platforms, 3913// although Niagara's hash function should help. 3914 3915void * ParkEvent::operator new (size_t sz) { 3916 return (void *) ((intptr_t (CHeapObj::operator new (sz + 256)) + 256) & -256) ; 3917} 3918 3919void ParkEvent::operator delete (void * a) { 3920 // ParkEvents are type-stable and immortal ... 3921 ShouldNotReachHere(); 3922} 3923 3924 3925// 6399321 As a temporary measure we copied & modified the ParkEvent:: 3926// allocate() and release() code for use by Parkers. The Parker:: forms 3927// will eventually be removed as we consolide and shift over to ParkEvents 3928// for both builtin synchronization and JSR166 operations. 3929 3930volatile int Parker::ListLock = 0 ; 3931Parker * volatile Parker::FreeList = NULL ; 3932 3933Parker * Parker::Allocate (JavaThread * t) { 3934 guarantee (t != NULL, "invariant") ; 3935 Parker * p ; 3936 3937 // Start by trying to recycle an existing but unassociated 3938 // Parker from the global free list. 3939 for (;;) { 3940 p = FreeList ; 3941 if (p == NULL) break ; 3942 // 1: Detach 3943 // Tantamount to p = Swap (&FreeList, NULL) 3944 if (Atomic::cmpxchg_ptr (NULL, &FreeList, p) != p) { 3945 continue ; 3946 } 3947 3948 // We've detached the list. The list in-hand is now 3949 // local to this thread. This thread can operate on the 3950 // list without risk of interference from other threads. 3951 // 2: Extract -- pop the 1st element from the list. 3952 Parker * List = p->FreeNext ; 3953 if (List == NULL) break ; 3954 for (;;) { 3955 // 3: Try to reattach the residual list 3956 guarantee (List != NULL, "invariant") ; 3957 Parker * Arv = (Parker *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ; 3958 if (Arv == NULL) break ; 3959 3960 // New nodes arrived. Try to detach the recent arrivals. 3961 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) { 3962 continue ; 3963 } 3964 guarantee (Arv != NULL, "invariant") ; 3965 // 4: Merge Arv into List 3966 Parker * Tail = List ; 3967 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ; 3968 Tail->FreeNext = Arv ; 3969 } 3970 break ; 3971 } 3972 3973 if (p != NULL) { 3974 guarantee (p->AssociatedWith == NULL, "invariant") ; 3975 } else { 3976 // Do this the hard way -- materialize a new Parker.. 3977 // In rare cases an allocating thread might detach 3978 // a long list -- installing null into FreeList --and 3979 // then stall. Another thread calling Allocate() would see 3980 // FreeList == null and then invoke the ctor. In this case we 3981 // end up with more Parkers in circulation than we need, but 3982 // the race is rare and the outcome is benign. 3983 // Ideally, the # of extant Parkers is equal to the 3984 // maximum # of threads that existed at any one time. 3985 // Because of the race mentioned above, segments of the 3986 // freelist can be transiently inaccessible. At worst 3987 // we may end up with the # of Parkers in circulation 3988 // slightly above the ideal. 3989 p = new Parker() ; 3990 } 3991 p->AssociatedWith = t ; // Associate p with t 3992 p->FreeNext = NULL ; 3993 return p ; 3994} 3995 3996 3997void Parker::Release (Parker * p) { 3998 if (p == NULL) return ; 3999 guarantee (p->AssociatedWith != NULL, "invariant") ; 4000 guarantee (p->FreeNext == NULL , "invariant") ; 4001 p->AssociatedWith = NULL ; 4002 for (;;) { 4003 // Push p onto FreeList 4004 Parker * List = FreeList ; 4005 p->FreeNext = List ; 4006 if (Atomic::cmpxchg_ptr (p, &FreeList, List) == List) break ; 4007 } 4008} 4009 4010void Threads::verify() { 4011 ALL_JAVA_THREADS(p) { 4012 p->verify(); 4013 } 4014 VMThread* thread = VMThread::vm_thread(); 4015 if (thread != NULL) thread->verify(); 4016} 4017