thread.cpp revision 62:cd0742ba123c
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 set_saved_exception_pc(NULL); 1142 set_threadObj(NULL); 1143 _anchor.clear(); 1144 set_entry_point(NULL); 1145 set_jni_functions(jni_functions()); 1146 set_callee_target(NULL); 1147 set_vm_result(NULL); 1148 set_vm_result_2(NULL); 1149 set_vframe_array_head(NULL); 1150 set_vframe_array_last(NULL); 1151 set_deferred_locals(NULL); 1152 set_deopt_mark(NULL); 1153 clear_must_deopt_id(); 1154 set_monitor_chunks(NULL); 1155 set_next(NULL); 1156 set_thread_state(_thread_new); 1157 _terminated = _not_terminated; 1158 _privileged_stack_top = NULL; 1159 _array_for_gc = NULL; 1160 _suspend_equivalent = false; 1161 _in_deopt_handler = 0; 1162 _doing_unsafe_access = false; 1163 _stack_guard_state = stack_guard_unused; 1164 _exception_oop = NULL; 1165 _exception_pc = 0; 1166 _exception_handler_pc = 0; 1167 _exception_stack_size = 0; 1168 _jvmti_thread_state= NULL; 1169 _jvmti_get_loaded_classes_closure = NULL; 1170 _interp_only_mode = 0; 1171 _special_runtime_exit_condition = _no_async_condition; 1172 _pending_async_exception = NULL; 1173 _is_compiling = false; 1174 _thread_stat = NULL; 1175 _thread_stat = new ThreadStatistics(); 1176 _blocked_on_compilation = false; 1177 _jni_active_critical = 0; 1178 _do_not_unlock_if_synchronized = false; 1179 _cached_monitor_info = NULL; 1180 _parker = Parker::Allocate(this) ; 1181 1182#ifndef PRODUCT 1183 _jmp_ring_index = 0; 1184 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1185 record_jump(NULL, NULL, NULL, 0); 1186 } 1187#endif /* PRODUCT */ 1188 1189 set_thread_profiler(NULL); 1190 if (FlatProfiler::is_active()) { 1191 // This is where we would decide to either give each thread it's own profiler 1192 // or use one global one from FlatProfiler, 1193 // or up to some count of the number of profiled threads, etc. 1194 ThreadProfiler* pp = new ThreadProfiler(); 1195 pp->engage(); 1196 set_thread_profiler(pp); 1197 } 1198 1199 // Setup safepoint state info for this thread 1200 ThreadSafepointState::create(this); 1201 1202 debug_only(_java_call_counter = 0); 1203 1204 // JVMTI PopFrame support 1205 _popframe_condition = popframe_inactive; 1206 _popframe_preserved_args = NULL; 1207 _popframe_preserved_args_size = 0; 1208 1209 pd_initialize(); 1210} 1211 1212JavaThread::JavaThread(bool is_attaching) : Thread() { 1213 initialize(); 1214 _is_attaching = is_attaching; 1215} 1216 1217bool JavaThread::reguard_stack(address cur_sp) { 1218 if (_stack_guard_state != stack_guard_yellow_disabled) { 1219 return true; // Stack already guarded or guard pages not needed. 1220 } 1221 1222 if (register_stack_overflow()) { 1223 // For those architectures which have separate register and 1224 // memory stacks, we must check the register stack to see if 1225 // it has overflowed. 1226 return false; 1227 } 1228 1229 // Java code never executes within the yellow zone: the latter is only 1230 // there to provoke an exception during stack banging. If java code 1231 // is executing there, either StackShadowPages should be larger, or 1232 // some exception code in c1, c2 or the interpreter isn't unwinding 1233 // when it should. 1234 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1235 1236 enable_stack_yellow_zone(); 1237 return true; 1238} 1239 1240bool JavaThread::reguard_stack(void) { 1241 return reguard_stack(os::current_stack_pointer()); 1242} 1243 1244 1245void JavaThread::block_if_vm_exited() { 1246 if (_terminated == _vm_exited) { 1247 // _vm_exited is set at safepoint, and Threads_lock is never released 1248 // we will block here forever 1249 Threads_lock->lock_without_safepoint_check(); 1250 ShouldNotReachHere(); 1251 } 1252} 1253 1254 1255// Remove this ifdef when C1 is ported to the compiler interface. 1256static void compiler_thread_entry(JavaThread* thread, TRAPS); 1257 1258JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : Thread() { 1259 if (TraceThreadEvents) { 1260 tty->print_cr("creating thread %p", this); 1261 } 1262 initialize(); 1263 _is_attaching = false; 1264 set_entry_point(entry_point); 1265 // Create the native thread itself. 1266 // %note runtime_23 1267 os::ThreadType thr_type = os::java_thread; 1268 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1269 os::java_thread; 1270 os::create_thread(this, thr_type, stack_sz); 1271 1272 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1273 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1274 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1275 // the exception consists of creating the exception object & initializing it, initialization 1276 // will leave the VM via a JavaCall and then all locks must be unlocked). 1277 // 1278 // The thread is still suspended when we reach here. Thread must be explicit started 1279 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1280 // by calling Threads:add. The reason why this is not done here, is because the thread 1281 // object must be fully initialized (take a look at JVM_Start) 1282} 1283 1284JavaThread::~JavaThread() { 1285 if (TraceThreadEvents) { 1286 tty->print_cr("terminate thread %p", this); 1287 } 1288 1289 // JSR166 -- return the parker to the free list 1290 Parker::Release(_parker); 1291 _parker = NULL ; 1292 1293 // Free any remaining previous UnrollBlock 1294 vframeArray* old_array = vframe_array_last(); 1295 1296 if (old_array != NULL) { 1297 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1298 old_array->set_unroll_block(NULL); 1299 delete old_info; 1300 delete old_array; 1301 } 1302 1303 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1304 if (deferred != NULL) { 1305 // This can only happen if thread is destroyed before deoptimization occurs. 1306 assert(deferred->length() != 0, "empty array!"); 1307 do { 1308 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1309 deferred->remove_at(0); 1310 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1311 delete dlv; 1312 } while (deferred->length() != 0); 1313 delete deferred; 1314 } 1315 1316 // All Java related clean up happens in exit 1317 ThreadSafepointState::destroy(this); 1318 if (_thread_profiler != NULL) delete _thread_profiler; 1319 if (_thread_stat != NULL) delete _thread_stat; 1320} 1321 1322 1323// The first routine called by a new Java thread 1324void JavaThread::run() { 1325 // initialize thread-local alloc buffer related fields 1326 this->initialize_tlab(); 1327 1328 // used to test validitity of stack trace backs 1329 this->record_base_of_stack_pointer(); 1330 1331 // Record real stack base and size. 1332 this->record_stack_base_and_size(); 1333 1334 // Initialize thread local storage; set before calling MutexLocker 1335 this->initialize_thread_local_storage(); 1336 1337 this->create_stack_guard_pages(); 1338 1339 // Thread is now sufficient initialized to be handled by the safepoint code as being 1340 // in the VM. Change thread state from _thread_new to _thread_in_vm 1341 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1342 1343 assert(JavaThread::current() == this, "sanity check"); 1344 assert(!Thread::current()->owns_locks(), "sanity check"); 1345 1346 DTRACE_THREAD_PROBE(start, this); 1347 1348 // This operation might block. We call that after all safepoint checks for a new thread has 1349 // been completed. 1350 this->set_active_handles(JNIHandleBlock::allocate_block()); 1351 1352 if (JvmtiExport::should_post_thread_life()) { 1353 JvmtiExport::post_thread_start(this); 1354 } 1355 1356 // We call another function to do the rest so we are sure that the stack addresses used 1357 // from there will be lower than the stack base just computed 1358 thread_main_inner(); 1359 1360 // Note, thread is no longer valid at this point! 1361} 1362 1363 1364void JavaThread::thread_main_inner() { 1365 assert(JavaThread::current() == this, "sanity check"); 1366 assert(this->threadObj() != NULL, "just checking"); 1367 1368 // Execute thread entry point. If this thread is being asked to restart, 1369 // or has been stopped before starting, do not reexecute entry point. 1370 // Note: Due to JVM_StopThread we can have pending exceptions already! 1371 if (!this->has_pending_exception() && !java_lang_Thread::is_stillborn(this->threadObj())) { 1372 // enter the thread's entry point only if we have no pending exceptions 1373 HandleMark hm(this); 1374 this->entry_point()(this, this); 1375 } 1376 1377 DTRACE_THREAD_PROBE(stop, this); 1378 1379 this->exit(false); 1380 delete this; 1381} 1382 1383 1384static void ensure_join(JavaThread* thread) { 1385 // We do not need to grap the Threads_lock, since we are operating on ourself. 1386 Handle threadObj(thread, thread->threadObj()); 1387 assert(threadObj.not_null(), "java thread object must exist"); 1388 ObjectLocker lock(threadObj, thread); 1389 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1390 thread->clear_pending_exception(); 1391 // It is of profound importance that we set the stillborn bit and reset the thread object, 1392 // before we do the notify. Since, changing these two variable will make JVM_IsAlive return 1393 // false. So in case another thread is doing a join on this thread , it will detect that the thread 1394 // is dead when it gets notified. 1395 java_lang_Thread::set_stillborn(threadObj()); 1396 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1397 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1398 java_lang_Thread::set_thread(threadObj(), NULL); 1399 lock.notify_all(thread); 1400 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1401 thread->clear_pending_exception(); 1402} 1403 1404// For any new cleanup additions, please check to see if they need to be applied to 1405// cleanup_failed_attach_current_thread as well. 1406void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1407 assert(this == JavaThread::current(), "thread consistency check"); 1408 if (!InitializeJavaLangSystem) return; 1409 1410 HandleMark hm(this); 1411 Handle uncaught_exception(this, this->pending_exception()); 1412 this->clear_pending_exception(); 1413 Handle threadObj(this, this->threadObj()); 1414 assert(threadObj.not_null(), "Java thread object should be created"); 1415 1416 if (get_thread_profiler() != NULL) { 1417 get_thread_profiler()->disengage(); 1418 ResourceMark rm; 1419 get_thread_profiler()->print(get_thread_name()); 1420 } 1421 1422 1423 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1424 { 1425 EXCEPTION_MARK; 1426 1427 CLEAR_PENDING_EXCEPTION; 1428 } 1429 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1430 // has to be fixed by a runtime query method 1431 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1432 // JSR-166: change call from from ThreadGroup.uncaughtException to 1433 // java.lang.Thread.dispatchUncaughtException 1434 if (uncaught_exception.not_null()) { 1435 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1436 Events::log("uncaught exception INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT", 1437 (address)uncaught_exception(), (address)threadObj(), (address)group()); 1438 { 1439 EXCEPTION_MARK; 1440 // Check if the method Thread.dispatchUncaughtException() exists. If so 1441 // call it. Otherwise we have an older library without the JSR-166 changes, 1442 // so call ThreadGroup.uncaughtException() 1443 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1444 CallInfo callinfo; 1445 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass()); 1446 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1447 vmSymbolHandles::dispatchUncaughtException_name(), 1448 vmSymbolHandles::throwable_void_signature(), 1449 KlassHandle(), false, false, THREAD); 1450 CLEAR_PENDING_EXCEPTION; 1451 methodHandle method = callinfo.selected_method(); 1452 if (method.not_null()) { 1453 JavaValue result(T_VOID); 1454 JavaCalls::call_virtual(&result, 1455 threadObj, thread_klass, 1456 vmSymbolHandles::dispatchUncaughtException_name(), 1457 vmSymbolHandles::throwable_void_signature(), 1458 uncaught_exception, 1459 THREAD); 1460 } else { 1461 KlassHandle thread_group(THREAD, SystemDictionary::threadGroup_klass()); 1462 JavaValue result(T_VOID); 1463 JavaCalls::call_virtual(&result, 1464 group, thread_group, 1465 vmSymbolHandles::uncaughtException_name(), 1466 vmSymbolHandles::thread_throwable_void_signature(), 1467 threadObj, // Arg 1 1468 uncaught_exception, // Arg 2 1469 THREAD); 1470 } 1471 CLEAR_PENDING_EXCEPTION; 1472 } 1473 } 1474 1475 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1476 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1477 // is deprecated anyhow. 1478 { int count = 3; 1479 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1480 EXCEPTION_MARK; 1481 JavaValue result(T_VOID); 1482 KlassHandle thread_klass(THREAD, SystemDictionary::thread_klass()); 1483 JavaCalls::call_virtual(&result, 1484 threadObj, thread_klass, 1485 vmSymbolHandles::exit_method_name(), 1486 vmSymbolHandles::void_method_signature(), 1487 THREAD); 1488 CLEAR_PENDING_EXCEPTION; 1489 } 1490 } 1491 1492 // notify JVMTI 1493 if (JvmtiExport::should_post_thread_life()) { 1494 JvmtiExport::post_thread_end(this); 1495 } 1496 1497 // We have notified the agents that we are exiting, before we go on, 1498 // we must check for a pending external suspend request and honor it 1499 // in order to not surprise the thread that made the suspend request. 1500 while (true) { 1501 { 1502 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1503 if (!is_external_suspend()) { 1504 set_terminated(_thread_exiting); 1505 ThreadService::current_thread_exiting(this); 1506 break; 1507 } 1508 // Implied else: 1509 // Things get a little tricky here. We have a pending external 1510 // suspend request, but we are holding the SR_lock so we 1511 // can't just self-suspend. So we temporarily drop the lock 1512 // and then self-suspend. 1513 } 1514 1515 ThreadBlockInVM tbivm(this); 1516 java_suspend_self(); 1517 1518 // We're done with this suspend request, but we have to loop around 1519 // and check again. Eventually we will get SR_lock without a pending 1520 // external suspend request and will be able to mark ourselves as 1521 // exiting. 1522 } 1523 // no more external suspends are allowed at this point 1524 } else { 1525 // before_exit() has already posted JVMTI THREAD_END events 1526 } 1527 1528 // Notify waiters on thread object. This has to be done after exit() is called 1529 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1530 // group should have the destroyed bit set before waiters are notified). 1531 ensure_join(this); 1532 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1533 1534 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1535 // held by this thread must be released. A detach operation must only 1536 // get here if there are no Java frames on the stack. Therefore, any 1537 // owned monitors at this point MUST be JNI-acquired monitors which are 1538 // pre-inflated and in the monitor cache. 1539 // 1540 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1541 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1542 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1543 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1544 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1545 } 1546 1547 // These things needs to be done while we are still a Java Thread. Make sure that thread 1548 // is in a consistent state, in case GC happens 1549 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1550 1551 if (active_handles() != NULL) { 1552 JNIHandleBlock* block = active_handles(); 1553 set_active_handles(NULL); 1554 JNIHandleBlock::release_block(block); 1555 } 1556 1557 if (free_handle_block() != NULL) { 1558 JNIHandleBlock* block = free_handle_block(); 1559 set_free_handle_block(NULL); 1560 JNIHandleBlock::release_block(block); 1561 } 1562 1563 // These have to be removed while this is still a valid thread. 1564 remove_stack_guard_pages(); 1565 1566 if (UseTLAB) { 1567 tlab().make_parsable(true); // retire TLAB 1568 } 1569 1570 if (jvmti_thread_state() != NULL) { 1571 JvmtiExport::cleanup_thread(this); 1572 } 1573 1574 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1575 Threads::remove(this); 1576} 1577 1578void JavaThread::cleanup_failed_attach_current_thread() { 1579 1580 if (get_thread_profiler() != NULL) { 1581 get_thread_profiler()->disengage(); 1582 ResourceMark rm; 1583 get_thread_profiler()->print(get_thread_name()); 1584 } 1585 1586 if (active_handles() != NULL) { 1587 JNIHandleBlock* block = active_handles(); 1588 set_active_handles(NULL); 1589 JNIHandleBlock::release_block(block); 1590 } 1591 1592 if (free_handle_block() != NULL) { 1593 JNIHandleBlock* block = free_handle_block(); 1594 set_free_handle_block(NULL); 1595 JNIHandleBlock::release_block(block); 1596 } 1597 1598 if (UseTLAB) { 1599 tlab().make_parsable(true); // retire TLAB, if any 1600 } 1601 1602 Threads::remove(this); 1603 delete this; 1604} 1605 1606 1607JavaThread* JavaThread::active() { 1608 Thread* thread = ThreadLocalStorage::thread(); 1609 assert(thread != NULL, "just checking"); 1610 if (thread->is_Java_thread()) { 1611 return (JavaThread*) thread; 1612 } else { 1613 assert(thread->is_VM_thread(), "this must be a vm thread"); 1614 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1615 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1616 assert(ret->is_Java_thread(), "must be a Java thread"); 1617 return ret; 1618 } 1619} 1620 1621bool JavaThread::is_lock_owned(address adr) const { 1622 if (lock_is_in_stack(adr)) return true; 1623 1624 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1625 if (chunk->contains(adr)) return true; 1626 } 1627 1628 return false; 1629} 1630 1631 1632void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1633 chunk->set_next(monitor_chunks()); 1634 set_monitor_chunks(chunk); 1635} 1636 1637void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1638 guarantee(monitor_chunks() != NULL, "must be non empty"); 1639 if (monitor_chunks() == chunk) { 1640 set_monitor_chunks(chunk->next()); 1641 } else { 1642 MonitorChunk* prev = monitor_chunks(); 1643 while (prev->next() != chunk) prev = prev->next(); 1644 prev->set_next(chunk->next()); 1645 } 1646} 1647 1648// JVM support. 1649 1650// Note: this function shouldn't block if it's called in 1651// _thread_in_native_trans state (such as from 1652// check_special_condition_for_native_trans()). 1653void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 1654 1655 if (has_last_Java_frame() && has_async_condition()) { 1656 // If we are at a polling page safepoint (not a poll return) 1657 // then we must defer async exception because live registers 1658 // will be clobbered by the exception path. Poll return is 1659 // ok because the call we a returning from already collides 1660 // with exception handling registers and so there is no issue. 1661 // (The exception handling path kills call result registers but 1662 // this is ok since the exception kills the result anyway). 1663 1664 if (is_at_poll_safepoint()) { 1665 // if the code we are returning to has deoptimized we must defer 1666 // the exception otherwise live registers get clobbered on the 1667 // exception path before deoptimization is able to retrieve them. 1668 // 1669 RegisterMap map(this, false); 1670 frame caller_fr = last_frame().sender(&map); 1671 assert(caller_fr.is_compiled_frame(), "what?"); 1672 if (caller_fr.is_deoptimized_frame()) { 1673 if (TraceExceptions) { 1674 ResourceMark rm; 1675 tty->print_cr("deferred async exception at compiled safepoint"); 1676 } 1677 return; 1678 } 1679 } 1680 } 1681 1682 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 1683 if (condition == _no_async_condition) { 1684 // Conditions have changed since has_special_runtime_exit_condition() 1685 // was called: 1686 // - if we were here only because of an external suspend request, 1687 // then that was taken care of above (or cancelled) so we are done 1688 // - if we were here because of another async request, then it has 1689 // been cleared between the has_special_runtime_exit_condition() 1690 // and now so again we are done 1691 return; 1692 } 1693 1694 // Check for pending async. exception 1695 if (_pending_async_exception != NULL) { 1696 // Only overwrite an already pending exception, if it is not a threadDeath. 1697 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::threaddeath_klass())) { 1698 1699 // We cannot call Exceptions::_throw(...) here because we cannot block 1700 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 1701 1702 if (TraceExceptions) { 1703 ResourceMark rm; 1704 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 1705 if (has_last_Java_frame() ) { 1706 frame f = last_frame(); 1707 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 1708 } 1709 tty->print_cr(" of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name()); 1710 } 1711 _pending_async_exception = NULL; 1712 clear_has_async_exception(); 1713 } 1714 } 1715 1716 if (check_unsafe_error && 1717 condition == _async_unsafe_access_error && !has_pending_exception()) { 1718 condition = _no_async_condition; // done 1719 switch (thread_state()) { 1720 case _thread_in_vm: 1721 { 1722 JavaThread* THREAD = this; 1723 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 1724 } 1725 case _thread_in_native: 1726 { 1727 ThreadInVMfromNative tiv(this); 1728 JavaThread* THREAD = this; 1729 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 1730 } 1731 case _thread_in_Java: 1732 { 1733 ThreadInVMfromJava tiv(this); 1734 JavaThread* THREAD = this; 1735 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 1736 } 1737 default: 1738 ShouldNotReachHere(); 1739 } 1740 } 1741 1742 assert(condition == _no_async_condition || has_pending_exception() || 1743 (!check_unsafe_error && condition == _async_unsafe_access_error), 1744 "must have handled the async condition, if no exception"); 1745} 1746 1747void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 1748 // 1749 // Check for pending external suspend. Internal suspend requests do 1750 // not use handle_special_runtime_exit_condition(). 1751 // If JNIEnv proxies are allowed, don't self-suspend if the target 1752 // thread is not the current thread. In older versions of jdbx, jdbx 1753 // threads could call into the VM with another thread's JNIEnv so we 1754 // can be here operating on behalf of a suspended thread (4432884). 1755 bool do_self_suspend = is_external_suspend_with_lock(); 1756 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 1757 // 1758 // Because thread is external suspended the safepoint code will count 1759 // thread as at a safepoint. This can be odd because we can be here 1760 // as _thread_in_Java which would normally transition to _thread_blocked 1761 // at a safepoint. We would like to mark the thread as _thread_blocked 1762 // before calling java_suspend_self like all other callers of it but 1763 // we must then observe proper safepoint protocol. (We can't leave 1764 // _thread_blocked with a safepoint in progress). However we can be 1765 // here as _thread_in_native_trans so we can't use a normal transition 1766 // constructor/destructor pair because they assert on that type of 1767 // transition. We could do something like: 1768 // 1769 // JavaThreadState state = thread_state(); 1770 // set_thread_state(_thread_in_vm); 1771 // { 1772 // ThreadBlockInVM tbivm(this); 1773 // java_suspend_self() 1774 // } 1775 // set_thread_state(_thread_in_vm_trans); 1776 // if (safepoint) block; 1777 // set_thread_state(state); 1778 // 1779 // but that is pretty messy. Instead we just go with the way the 1780 // code has worked before and note that this is the only path to 1781 // java_suspend_self that doesn't put the thread in _thread_blocked 1782 // mode. 1783 1784 frame_anchor()->make_walkable(this); 1785 java_suspend_self(); 1786 1787 // We might be here for reasons in addition to the self-suspend request 1788 // so check for other async requests. 1789 } 1790 1791 if (check_asyncs) { 1792 check_and_handle_async_exceptions(); 1793 } 1794} 1795 1796void JavaThread::send_thread_stop(oop java_throwable) { 1797 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 1798 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 1799 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 1800 1801 // Do not throw asynchronous exceptions against the compiler thread 1802 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 1803 if (is_Compiler_thread()) return; 1804 1805 // This is a change from JDK 1.1, but JDK 1.2 will also do it: 1806 if (java_throwable->is_a(SystemDictionary::threaddeath_klass())) { 1807 java_lang_Thread::set_stillborn(threadObj()); 1808 } 1809 1810 { 1811 // Actually throw the Throwable against the target Thread - however 1812 // only if there is no thread death exception installed already. 1813 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::threaddeath_klass())) { 1814 // If the topmost frame is a runtime stub, then we are calling into 1815 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 1816 // must deoptimize the caller before continuing, as the compiled exception handler table 1817 // may not be valid 1818 if (has_last_Java_frame()) { 1819 frame f = last_frame(); 1820 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 1821 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 1822 RegisterMap reg_map(this, UseBiasedLocking); 1823 frame compiled_frame = f.sender(®_map); 1824 if (compiled_frame.can_be_deoptimized()) { 1825 Deoptimization::deoptimize(this, compiled_frame, ®_map); 1826 } 1827 } 1828 } 1829 1830 // Set async. pending exception in thread. 1831 set_pending_async_exception(java_throwable); 1832 1833 if (TraceExceptions) { 1834 ResourceMark rm; 1835 tty->print_cr("Pending Async. exception installed of type: %s", instanceKlass::cast(_pending_async_exception->klass())->external_name()); 1836 } 1837 // for AbortVMOnException flag 1838 NOT_PRODUCT(Exceptions::debug_check_abort(instanceKlass::cast(_pending_async_exception->klass())->external_name())); 1839 } 1840 } 1841 1842 1843 // Interrupt thread so it will wake up from a potential wait() 1844 Thread::interrupt(this); 1845} 1846 1847// External suspension mechanism. 1848// 1849// Tell the VM to suspend a thread when ever it knows that it does not hold on 1850// to any VM_locks and it is at a transition 1851// Self-suspension will happen on the transition out of the vm. 1852// Catch "this" coming in from JNIEnv pointers when the thread has been freed 1853// 1854// Guarantees on return: 1855// + Target thread will not execute any new bytecode (that's why we need to 1856// force a safepoint) 1857// + Target thread will not enter any new monitors 1858// 1859void JavaThread::java_suspend() { 1860 { MutexLocker mu(Threads_lock); 1861 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 1862 return; 1863 } 1864 } 1865 1866 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1867 if (!is_external_suspend()) { 1868 // a racing resume has cancelled us; bail out now 1869 return; 1870 } 1871 1872 // suspend is done 1873 uint32_t debug_bits = 0; 1874 // Warning: is_ext_suspend_completed() may temporarily drop the 1875 // SR_lock to allow the thread to reach a stable thread state if 1876 // it is currently in a transient thread state. 1877 if (is_ext_suspend_completed(false /* !called_by_wait */, 1878 SuspendRetryDelay, &debug_bits) ) { 1879 return; 1880 } 1881 } 1882 1883 VM_ForceSafepoint vm_suspend; 1884 VMThread::execute(&vm_suspend); 1885} 1886 1887// Part II of external suspension. 1888// A JavaThread self suspends when it detects a pending external suspend 1889// request. This is usually on transitions. It is also done in places 1890// where continuing to the next transition would surprise the caller, 1891// e.g., monitor entry. 1892// 1893// Returns the number of times that the thread self-suspended. 1894// 1895// Note: DO NOT call java_suspend_self() when you just want to block current 1896// thread. java_suspend_self() is the second stage of cooperative 1897// suspension for external suspend requests and should only be used 1898// to complete an external suspend request. 1899// 1900int JavaThread::java_suspend_self() { 1901 int ret = 0; 1902 1903 // we are in the process of exiting so don't suspend 1904 if (is_exiting()) { 1905 clear_external_suspend(); 1906 return ret; 1907 } 1908 1909 assert(_anchor.walkable() || 1910 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 1911 "must have walkable stack"); 1912 1913 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1914 1915 assert(!this->is_any_suspended(), 1916 "a thread trying to self-suspend should not already be suspended"); 1917 1918 if (this->is_suspend_equivalent()) { 1919 // If we are self-suspending as a result of the lifting of a 1920 // suspend equivalent condition, then the suspend_equivalent 1921 // flag is not cleared until we set the ext_suspended flag so 1922 // that wait_for_ext_suspend_completion() returns consistent 1923 // results. 1924 this->clear_suspend_equivalent(); 1925 } 1926 1927 // A racing resume may have cancelled us before we grabbed SR_lock 1928 // above. Or another external suspend request could be waiting for us 1929 // by the time we return from SR_lock()->wait(). The thread 1930 // that requested the suspension may already be trying to walk our 1931 // stack and if we return now, we can change the stack out from under 1932 // it. This would be a "bad thing (TM)" and cause the stack walker 1933 // to crash. We stay self-suspended until there are no more pending 1934 // external suspend requests. 1935 while (is_external_suspend()) { 1936 ret++; 1937 this->set_ext_suspended(); 1938 1939 // _ext_suspended flag is cleared by java_resume() 1940 while (is_ext_suspended()) { 1941 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 1942 } 1943 } 1944 1945 return ret; 1946} 1947 1948#ifdef ASSERT 1949// verify the JavaThread has not yet been published in the Threads::list, and 1950// hence doesn't need protection from concurrent access at this stage 1951void JavaThread::verify_not_published() { 1952 if (!Threads_lock->owned_by_self()) { 1953 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 1954 assert( !Threads::includes(this), 1955 "java thread shouldn't have been published yet!"); 1956 } 1957 else { 1958 assert( !Threads::includes(this), 1959 "java thread shouldn't have been published yet!"); 1960 } 1961} 1962#endif 1963 1964// Slow path when the native==>VM/Java barriers detect a safepoint is in 1965// progress or when _suspend_flags is non-zero. 1966// Current thread needs to self-suspend if there is a suspend request and/or 1967// block if a safepoint is in progress. 1968// Async exception ISN'T checked. 1969// Note only the ThreadInVMfromNative transition can call this function 1970// directly and when thread state is _thread_in_native_trans 1971void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 1972 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 1973 1974 JavaThread *curJT = JavaThread::current(); 1975 bool do_self_suspend = thread->is_external_suspend(); 1976 1977 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 1978 1979 // If JNIEnv proxies are allowed, don't self-suspend if the target 1980 // thread is not the current thread. In older versions of jdbx, jdbx 1981 // threads could call into the VM with another thread's JNIEnv so we 1982 // can be here operating on behalf of a suspended thread (4432884). 1983 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 1984 JavaThreadState state = thread->thread_state(); 1985 1986 // We mark this thread_blocked state as a suspend-equivalent so 1987 // that a caller to is_ext_suspend_completed() won't be confused. 1988 // The suspend-equivalent state is cleared by java_suspend_self(). 1989 thread->set_suspend_equivalent(); 1990 1991 // If the safepoint code sees the _thread_in_native_trans state, it will 1992 // wait until the thread changes to other thread state. There is no 1993 // guarantee on how soon we can obtain the SR_lock and complete the 1994 // self-suspend request. It would be a bad idea to let safepoint wait for 1995 // too long. Temporarily change the state to _thread_blocked to 1996 // let the VM thread know that this thread is ready for GC. The problem 1997 // of changing thread state is that safepoint could happen just after 1998 // java_suspend_self() returns after being resumed, and VM thread will 1999 // see the _thread_blocked state. We must check for safepoint 2000 // after restoring the state and make sure we won't leave while a safepoint 2001 // is in progress. 2002 thread->set_thread_state(_thread_blocked); 2003 thread->java_suspend_self(); 2004 thread->set_thread_state(state); 2005 // Make sure new state is seen by VM thread 2006 if (os::is_MP()) { 2007 if (UseMembar) { 2008 // Force a fence between the write above and read below 2009 OrderAccess::fence(); 2010 } else { 2011 // Must use this rather than serialization page in particular on Windows 2012 InterfaceSupport::serialize_memory(thread); 2013 } 2014 } 2015 } 2016 2017 if (SafepointSynchronize::do_call_back()) { 2018 // If we are safepointing, then block the caller which may not be 2019 // the same as the target thread (see above). 2020 SafepointSynchronize::block(curJT); 2021 } 2022 2023 if (thread->is_deopt_suspend()) { 2024 thread->clear_deopt_suspend(); 2025 RegisterMap map(thread, false); 2026 frame f = thread->last_frame(); 2027 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2028 f = f.sender(&map); 2029 } 2030 if (f.id() == thread->must_deopt_id()) { 2031 thread->clear_must_deopt_id(); 2032 // Since we know we're safe to deopt the current state is a safe state 2033 f.deoptimize(thread, true); 2034 } else { 2035 fatal("missed deoptimization!"); 2036 } 2037 } 2038} 2039 2040// Slow path when the native==>VM/Java barriers detect a safepoint is in 2041// progress or when _suspend_flags is non-zero. 2042// Current thread needs to self-suspend if there is a suspend request and/or 2043// block if a safepoint is in progress. 2044// Also check for pending async exception (not including unsafe access error). 2045// Note only the native==>VM/Java barriers can call this function and when 2046// thread state is _thread_in_native_trans. 2047void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2048 check_safepoint_and_suspend_for_native_trans(thread); 2049 2050 if (thread->has_async_exception()) { 2051 // We are in _thread_in_native_trans state, don't handle unsafe 2052 // access error since that may block. 2053 thread->check_and_handle_async_exceptions(false); 2054 } 2055} 2056 2057// We need to guarantee the Threads_lock here, since resumes are not 2058// allowed during safepoint synchronization 2059// Can only resume from an external suspension 2060void JavaThread::java_resume() { 2061 assert_locked_or_safepoint(Threads_lock); 2062 2063 // Sanity check: thread is gone, has started exiting or the thread 2064 // was not externally suspended. 2065 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2066 return; 2067 } 2068 2069 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2070 2071 clear_external_suspend(); 2072 2073 if (is_ext_suspended()) { 2074 clear_ext_suspended(); 2075 SR_lock()->notify_all(); 2076 } 2077} 2078 2079void JavaThread::create_stack_guard_pages() { 2080 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2081 address low_addr = stack_base() - stack_size(); 2082 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2083 2084 int allocate = os::allocate_stack_guard_pages(); 2085 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2086 2087 if (allocate && !os::commit_memory((char *) low_addr, len)) { 2088 warning("Attempt to allocate stack guard pages failed."); 2089 return; 2090 } 2091 2092 if (os::guard_memory((char *) low_addr, len)) { 2093 _stack_guard_state = stack_guard_enabled; 2094 } else { 2095 warning("Attempt to protect stack guard pages failed."); 2096 if (os::uncommit_memory((char *) low_addr, len)) { 2097 warning("Attempt to deallocate stack guard pages failed."); 2098 } 2099 } 2100} 2101 2102void JavaThread::remove_stack_guard_pages() { 2103 if (_stack_guard_state == stack_guard_unused) return; 2104 address low_addr = stack_base() - stack_size(); 2105 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2106 2107 if (os::allocate_stack_guard_pages()) { 2108 if (os::uncommit_memory((char *) low_addr, len)) { 2109 _stack_guard_state = stack_guard_unused; 2110 } else { 2111 warning("Attempt to deallocate stack guard pages failed."); 2112 } 2113 } else { 2114 if (_stack_guard_state == stack_guard_unused) return; 2115 if (os::unguard_memory((char *) low_addr, len)) { 2116 _stack_guard_state = stack_guard_unused; 2117 } else { 2118 warning("Attempt to unprotect stack guard pages failed."); 2119 } 2120 } 2121} 2122 2123void JavaThread::enable_stack_yellow_zone() { 2124 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2125 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2126 2127 // The base notation is from the stacks point of view, growing downward. 2128 // We need to adjust it to work correctly with guard_memory() 2129 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2130 2131 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2132 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2133 2134 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2135 _stack_guard_state = stack_guard_enabled; 2136 } else { 2137 warning("Attempt to guard stack yellow zone failed."); 2138 } 2139 enable_register_stack_guard(); 2140} 2141 2142void JavaThread::disable_stack_yellow_zone() { 2143 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2144 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2145 2146 // Simply return if called for a thread that does not use guard pages. 2147 if (_stack_guard_state == stack_guard_unused) return; 2148 2149 // The base notation is from the stacks point of view, growing downward. 2150 // We need to adjust it to work correctly with guard_memory() 2151 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2152 2153 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2154 _stack_guard_state = stack_guard_yellow_disabled; 2155 } else { 2156 warning("Attempt to unguard stack yellow zone failed."); 2157 } 2158 disable_register_stack_guard(); 2159} 2160 2161void JavaThread::enable_stack_red_zone() { 2162 // The base notation is from the stacks point of view, growing downward. 2163 // We need to adjust it to work correctly with guard_memory() 2164 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2165 address base = stack_red_zone_base() - stack_red_zone_size(); 2166 2167 guarantee(base < stack_base(),"Error calculating stack red zone"); 2168 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2169 2170 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2171 warning("Attempt to guard stack red zone failed."); 2172 } 2173} 2174 2175void JavaThread::disable_stack_red_zone() { 2176 // The base notation is from the stacks point of view, growing downward. 2177 // We need to adjust it to work correctly with guard_memory() 2178 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2179 address base = stack_red_zone_base() - stack_red_zone_size(); 2180 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2181 warning("Attempt to unguard stack red zone failed."); 2182 } 2183} 2184 2185void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2186 // ignore is there is no stack 2187 if (!has_last_Java_frame()) return; 2188 // traverse the stack frames. Starts from top frame. 2189 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2190 frame* fr = fst.current(); 2191 f(fr, fst.register_map()); 2192 } 2193} 2194 2195 2196#ifndef PRODUCT 2197// Deoptimization 2198// Function for testing deoptimization 2199void JavaThread::deoptimize() { 2200 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2201 StackFrameStream fst(this, UseBiasedLocking); 2202 bool deopt = false; // Dump stack only if a deopt actually happens. 2203 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2204 // Iterate over all frames in the thread and deoptimize 2205 for(; !fst.is_done(); fst.next()) { 2206 if(fst.current()->can_be_deoptimized()) { 2207 2208 if (only_at) { 2209 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2210 // consists of comma or carriage return separated numbers so 2211 // search for the current bci in that string. 2212 address pc = fst.current()->pc(); 2213 nmethod* nm = (nmethod*) fst.current()->cb(); 2214 ScopeDesc* sd = nm->scope_desc_at( pc); 2215 char buffer[8]; 2216 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2217 size_t len = strlen(buffer); 2218 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2219 while (found != NULL) { 2220 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2221 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2222 // Check that the bci found is bracketed by terminators. 2223 break; 2224 } 2225 found = strstr(found + 1, buffer); 2226 } 2227 if (!found) { 2228 continue; 2229 } 2230 } 2231 2232 if (DebugDeoptimization && !deopt) { 2233 deopt = true; // One-time only print before deopt 2234 tty->print_cr("[BEFORE Deoptimization]"); 2235 trace_frames(); 2236 trace_stack(); 2237 } 2238 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2239 } 2240 } 2241 2242 if (DebugDeoptimization && deopt) { 2243 tty->print_cr("[AFTER Deoptimization]"); 2244 trace_frames(); 2245 } 2246} 2247 2248 2249// Make zombies 2250void JavaThread::make_zombies() { 2251 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2252 if (fst.current()->can_be_deoptimized()) { 2253 // it is a Java nmethod 2254 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2255 nm->make_not_entrant(); 2256 } 2257 } 2258} 2259#endif // PRODUCT 2260 2261 2262void JavaThread::deoptimized_wrt_marked_nmethods() { 2263 if (!has_last_Java_frame()) return; 2264 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2265 StackFrameStream fst(this, UseBiasedLocking); 2266 for(; !fst.is_done(); fst.next()) { 2267 if (fst.current()->should_be_deoptimized()) { 2268 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2269 } 2270 } 2271} 2272 2273 2274// GC support 2275static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2276 2277void JavaThread::gc_epilogue() { 2278 frames_do(frame_gc_epilogue); 2279} 2280 2281 2282static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2283 2284void JavaThread::gc_prologue() { 2285 frames_do(frame_gc_prologue); 2286} 2287 2288 2289void JavaThread::oops_do(OopClosure* f) { 2290 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2291 // since there may be more than one thread using each ThreadProfiler. 2292 2293 // Traverse the GCHandles 2294 Thread::oops_do(f); 2295 2296 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2297 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2298 2299 if (has_last_Java_frame()) { 2300 2301 // Traverse the privileged stack 2302 if (_privileged_stack_top != NULL) { 2303 _privileged_stack_top->oops_do(f); 2304 } 2305 2306 // traverse the registered growable array 2307 if (_array_for_gc != NULL) { 2308 for (int index = 0; index < _array_for_gc->length(); index++) { 2309 f->do_oop(_array_for_gc->adr_at(index)); 2310 } 2311 } 2312 2313 // Traverse the monitor chunks 2314 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2315 chunk->oops_do(f); 2316 } 2317 2318 // Traverse the execution stack 2319 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2320 fst.current()->oops_do(f, fst.register_map()); 2321 } 2322 } 2323 2324 // callee_target is never live across a gc point so NULL it here should 2325 // it still contain a methdOop. 2326 2327 set_callee_target(NULL); 2328 2329 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2330 // If we have deferred set_locals there might be oops waiting to be 2331 // written 2332 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2333 if (list != NULL) { 2334 for (int i = 0; i < list->length(); i++) { 2335 list->at(i)->oops_do(f); 2336 } 2337 } 2338 2339 // Traverse instance variables at the end since the GC may be moving things 2340 // around using this function 2341 f->do_oop((oop*) &_threadObj); 2342 f->do_oop((oop*) &_vm_result); 2343 f->do_oop((oop*) &_vm_result_2); 2344 f->do_oop((oop*) &_exception_oop); 2345 f->do_oop((oop*) &_pending_async_exception); 2346 2347 if (jvmti_thread_state() != NULL) { 2348 jvmti_thread_state()->oops_do(f); 2349 } 2350} 2351 2352void JavaThread::nmethods_do() { 2353 // Traverse the GCHandles 2354 Thread::nmethods_do(); 2355 2356 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2357 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2358 2359 if (has_last_Java_frame()) { 2360 // Traverse the execution stack 2361 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2362 fst.current()->nmethods_do(); 2363 } 2364 } 2365} 2366 2367// Printing 2368const char* _get_thread_state_name(JavaThreadState _thread_state) { 2369 switch (_thread_state) { 2370 case _thread_uninitialized: return "_thread_uninitialized"; 2371 case _thread_new: return "_thread_new"; 2372 case _thread_new_trans: return "_thread_new_trans"; 2373 case _thread_in_native: return "_thread_in_native"; 2374 case _thread_in_native_trans: return "_thread_in_native_trans"; 2375 case _thread_in_vm: return "_thread_in_vm"; 2376 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2377 case _thread_in_Java: return "_thread_in_Java"; 2378 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2379 case _thread_blocked: return "_thread_blocked"; 2380 case _thread_blocked_trans: return "_thread_blocked_trans"; 2381 default: return "unknown thread state"; 2382 } 2383} 2384 2385#ifndef PRODUCT 2386void JavaThread::print_thread_state_on(outputStream *st) const { 2387 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2388}; 2389void JavaThread::print_thread_state() const { 2390 print_thread_state_on(tty); 2391}; 2392#endif // PRODUCT 2393 2394// Called by Threads::print() for VM_PrintThreads operation 2395void JavaThread::print_on(outputStream *st) const { 2396 st->print("\"%s\" ", get_thread_name()); 2397 oop thread_oop = threadObj(); 2398 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2399 Thread::print_on(st); 2400 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2401 st->print_cr("[" INTPTR_FORMAT ".." INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12), highest_lock()); 2402 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2403 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2404 } 2405#ifndef PRODUCT 2406 print_thread_state_on(st); 2407 _safepoint_state->print_on(st); 2408#endif // PRODUCT 2409} 2410 2411// Called by fatal error handler. The difference between this and 2412// JavaThread::print() is that we can't grab lock or allocate memory. 2413void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2414 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2415 oop thread_obj = threadObj(); 2416 if (thread_obj != NULL) { 2417 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2418 } 2419 st->print(" ["); 2420 st->print("%s", _get_thread_state_name(_thread_state)); 2421 if (osthread()) { 2422 st->print(", id=%d", osthread()->thread_id()); 2423 } 2424 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2425 _stack_base - _stack_size, _stack_base); 2426 st->print("]"); 2427 return; 2428} 2429 2430// Verification 2431 2432static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2433 2434void JavaThread::verify() { 2435 // Verify oops in the thread. 2436 oops_do(&VerifyOopClosure::verify_oop); 2437 2438 // Verify the stack frames. 2439 frames_do(frame_verify); 2440} 2441 2442// CR 6300358 (sub-CR 2137150) 2443// Most callers of this method assume that it can't return NULL but a 2444// thread may not have a name whilst it is in the process of attaching to 2445// the VM - see CR 6412693, and there are places where a JavaThread can be 2446// seen prior to having it's threadObj set (eg JNI attaching threads and 2447// if vm exit occurs during initialization). These cases can all be accounted 2448// for such that this method never returns NULL. 2449const char* JavaThread::get_thread_name() const { 2450#ifdef ASSERT 2451 // early safepoints can hit while current thread does not yet have TLS 2452 if (!SafepointSynchronize::is_at_safepoint()) { 2453 Thread *cur = Thread::current(); 2454 if (!(cur->is_Java_thread() && cur == this)) { 2455 // Current JavaThreads are allowed to get their own name without 2456 // the Threads_lock. 2457 assert_locked_or_safepoint(Threads_lock); 2458 } 2459 } 2460#endif // ASSERT 2461 return get_thread_name_string(); 2462} 2463 2464// Returns a non-NULL representation of this thread's name, or a suitable 2465// descriptive string if there is no set name 2466const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2467 const char* name_str; 2468 oop thread_obj = threadObj(); 2469 if (thread_obj != NULL) { 2470 typeArrayOop name = java_lang_Thread::name(thread_obj); 2471 if (name != NULL) { 2472 if (buf == NULL) { 2473 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2474 } 2475 else { 2476 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2477 } 2478 } 2479 else if (is_attaching()) { // workaround for 6412693 - see 6404306 2480 name_str = "<no-name - thread is attaching>"; 2481 } 2482 else { 2483 name_str = Thread::name(); 2484 } 2485 } 2486 else { 2487 name_str = Thread::name(); 2488 } 2489 assert(name_str != NULL, "unexpected NULL thread name"); 2490 return name_str; 2491} 2492 2493 2494const char* JavaThread::get_threadgroup_name() const { 2495 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2496 oop thread_obj = threadObj(); 2497 if (thread_obj != NULL) { 2498 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2499 if (thread_group != NULL) { 2500 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2501 // ThreadGroup.name can be null 2502 if (name != NULL) { 2503 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2504 return str; 2505 } 2506 } 2507 } 2508 return NULL; 2509} 2510 2511const char* JavaThread::get_parent_name() const { 2512 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2513 oop thread_obj = threadObj(); 2514 if (thread_obj != NULL) { 2515 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2516 if (thread_group != NULL) { 2517 oop parent = java_lang_ThreadGroup::parent(thread_group); 2518 if (parent != NULL) { 2519 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2520 // ThreadGroup.name can be null 2521 if (name != NULL) { 2522 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2523 return str; 2524 } 2525 } 2526 } 2527 } 2528 return NULL; 2529} 2530 2531ThreadPriority JavaThread::java_priority() const { 2532 oop thr_oop = threadObj(); 2533 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2534 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2535 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2536 return priority; 2537} 2538 2539void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2540 2541 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2542 // Link Java Thread object <-> C++ Thread 2543 2544 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2545 // and put it into a new Handle. The Handle "thread_oop" can then 2546 // be used to pass the C++ thread object to other methods. 2547 2548 // Set the Java level thread object (jthread) field of the 2549 // new thread (a JavaThread *) to C++ thread object using the 2550 // "thread_oop" handle. 2551 2552 // Set the thread field (a JavaThread *) of the 2553 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2554 2555 Handle thread_oop(Thread::current(), 2556 JNIHandles::resolve_non_null(jni_thread)); 2557 assert(instanceKlass::cast(thread_oop->klass())->is_linked(), 2558 "must be initialized"); 2559 set_threadObj(thread_oop()); 2560 java_lang_Thread::set_thread(thread_oop(), this); 2561 2562 if (prio == NoPriority) { 2563 prio = java_lang_Thread::priority(thread_oop()); 2564 assert(prio != NoPriority, "A valid priority should be present"); 2565 } 2566 2567 // Push the Java priority down to the native thread; needs Threads_lock 2568 Thread::set_priority(this, prio); 2569 2570 // Add the new thread to the Threads list and set it in motion. 2571 // We must have threads lock in order to call Threads::add. 2572 // It is crucial that we do not block before the thread is 2573 // added to the Threads list for if a GC happens, then the java_thread oop 2574 // will not be visited by GC. 2575 Threads::add(this); 2576} 2577 2578oop JavaThread::current_park_blocker() { 2579 // Support for JSR-166 locks 2580 oop thread_oop = threadObj(); 2581 if (thread_oop != NULL && JDK_Version::supports_thread_park_blocker()) { 2582 return java_lang_Thread::park_blocker(thread_oop); 2583 } 2584 return NULL; 2585} 2586 2587 2588void JavaThread::print_stack_on(outputStream* st) { 2589 if (!has_last_Java_frame()) return; 2590 ResourceMark rm; 2591 HandleMark hm; 2592 2593 RegisterMap reg_map(this); 2594 vframe* start_vf = last_java_vframe(®_map); 2595 int count = 0; 2596 for (vframe* f = start_vf; f; f = f->sender() ) { 2597 if (f->is_java_frame()) { 2598 javaVFrame* jvf = javaVFrame::cast(f); 2599 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 2600 2601 // Print out lock information 2602 if (JavaMonitorsInStackTrace) { 2603 jvf->print_lock_info_on(st, count); 2604 } 2605 } else { 2606 // Ignore non-Java frames 2607 } 2608 2609 // Bail-out case for too deep stacks 2610 count++; 2611 if (MaxJavaStackTraceDepth == count) return; 2612 } 2613} 2614 2615 2616// JVMTI PopFrame support 2617void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 2618 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 2619 if (in_bytes(size_in_bytes) != 0) { 2620 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes)); 2621 _popframe_preserved_args_size = in_bytes(size_in_bytes); 2622 Copy::conjoint_bytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 2623 } 2624} 2625 2626void* JavaThread::popframe_preserved_args() { 2627 return _popframe_preserved_args; 2628} 2629 2630ByteSize JavaThread::popframe_preserved_args_size() { 2631 return in_ByteSize(_popframe_preserved_args_size); 2632} 2633 2634WordSize JavaThread::popframe_preserved_args_size_in_words() { 2635 int sz = in_bytes(popframe_preserved_args_size()); 2636 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 2637 return in_WordSize(sz / wordSize); 2638} 2639 2640void JavaThread::popframe_free_preserved_args() { 2641 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 2642 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 2643 _popframe_preserved_args = NULL; 2644 _popframe_preserved_args_size = 0; 2645} 2646 2647#ifndef PRODUCT 2648 2649void JavaThread::trace_frames() { 2650 tty->print_cr("[Describe stack]"); 2651 int frame_no = 1; 2652 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2653 tty->print(" %d. ", frame_no++); 2654 fst.current()->print_value_on(tty,this); 2655 tty->cr(); 2656 } 2657} 2658 2659 2660void JavaThread::trace_stack_from(vframe* start_vf) { 2661 ResourceMark rm; 2662 int vframe_no = 1; 2663 for (vframe* f = start_vf; f; f = f->sender() ) { 2664 if (f->is_java_frame()) { 2665 javaVFrame::cast(f)->print_activation(vframe_no++); 2666 } else { 2667 f->print(); 2668 } 2669 if (vframe_no > StackPrintLimit) { 2670 tty->print_cr("...<more frames>..."); 2671 return; 2672 } 2673 } 2674} 2675 2676 2677void JavaThread::trace_stack() { 2678 if (!has_last_Java_frame()) return; 2679 ResourceMark rm; 2680 HandleMark hm; 2681 RegisterMap reg_map(this); 2682 trace_stack_from(last_java_vframe(®_map)); 2683} 2684 2685 2686#endif // PRODUCT 2687 2688 2689javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 2690 assert(reg_map != NULL, "a map must be given"); 2691 frame f = last_frame(); 2692 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 2693 if (vf->is_java_frame()) return javaVFrame::cast(vf); 2694 } 2695 return NULL; 2696} 2697 2698 2699klassOop JavaThread::security_get_caller_class(int depth) { 2700 vframeStream vfst(this); 2701 vfst.security_get_caller_frame(depth); 2702 if (!vfst.at_end()) { 2703 return vfst.method()->method_holder(); 2704 } 2705 return NULL; 2706} 2707 2708static void compiler_thread_entry(JavaThread* thread, TRAPS) { 2709 assert(thread->is_Compiler_thread(), "must be compiler thread"); 2710 CompileBroker::compiler_thread_loop(); 2711} 2712 2713// Create a CompilerThread 2714CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 2715: JavaThread(&compiler_thread_entry) { 2716 _env = NULL; 2717 _log = NULL; 2718 _task = NULL; 2719 _queue = queue; 2720 _counters = counters; 2721 2722#ifndef PRODUCT 2723 _ideal_graph_printer = NULL; 2724#endif 2725} 2726 2727 2728// ======= Threads ======== 2729 2730// The Threads class links together all active threads, and provides 2731// operations over all threads. It is protected by its own Mutex 2732// lock, which is also used in other contexts to protect thread 2733// operations from having the thread being operated on from exiting 2734// and going away unexpectedly (e.g., safepoint synchronization) 2735 2736JavaThread* Threads::_thread_list = NULL; 2737int Threads::_number_of_threads = 0; 2738int Threads::_number_of_non_daemon_threads = 0; 2739int Threads::_return_code = 0; 2740size_t JavaThread::_stack_size_at_create = 0; 2741 2742// All JavaThreads 2743#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 2744 2745void os_stream(); 2746 2747// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 2748void Threads::threads_do(ThreadClosure* tc) { 2749 assert_locked_or_safepoint(Threads_lock); 2750 // ALL_JAVA_THREADS iterates through all JavaThreads 2751 ALL_JAVA_THREADS(p) { 2752 tc->do_thread(p); 2753 } 2754 // Someday we could have a table or list of all non-JavaThreads. 2755 // For now, just manually iterate through them. 2756 tc->do_thread(VMThread::vm_thread()); 2757 Universe::heap()->gc_threads_do(tc); 2758 tc->do_thread(WatcherThread::watcher_thread()); 2759 // If CompilerThreads ever become non-JavaThreads, add them here 2760} 2761 2762jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 2763 2764 // Check version 2765 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 2766 2767 // Initialize the output stream module 2768 ostream_init(); 2769 2770 // Process java launcher properties. 2771 Arguments::process_sun_java_launcher_properties(args); 2772 2773 // Initialize the os module before using TLS 2774 os::init(); 2775 2776 // Initialize system properties. 2777 Arguments::init_system_properties(); 2778 2779 // Parse arguments 2780 jint parse_result = Arguments::parse(args); 2781 if (parse_result != JNI_OK) return parse_result; 2782 2783 if (PauseAtStartup) { 2784 os::pause(); 2785 } 2786 2787 HS_DTRACE_PROBE(hotspot, vm__init__begin); 2788 2789 // Record VM creation timing statistics 2790 TraceVmCreationTime create_vm_timer; 2791 create_vm_timer.start(); 2792 2793 // Timing (must come after argument parsing) 2794 TraceTime timer("Create VM", TraceStartupTime); 2795 2796 // Initialize the os module after parsing the args 2797 jint os_init_2_result = os::init_2(); 2798 if (os_init_2_result != JNI_OK) return os_init_2_result; 2799 2800 // Initialize output stream logging 2801 ostream_init_log(); 2802 2803 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 2804 // Must be before create_vm_init_agents() 2805 if (Arguments::init_libraries_at_startup()) { 2806 convert_vm_init_libraries_to_agents(); 2807 } 2808 2809 // Launch -agentlib/-agentpath and converted -Xrun agents 2810 if (Arguments::init_agents_at_startup()) { 2811 create_vm_init_agents(); 2812 } 2813 2814 // Initialize Threads state 2815 _thread_list = NULL; 2816 _number_of_threads = 0; 2817 _number_of_non_daemon_threads = 0; 2818 2819 // Initialize TLS 2820 ThreadLocalStorage::init(); 2821 2822 // Initialize global data structures and create system classes in heap 2823 vm_init_globals(); 2824 2825 // Attach the main thread to this os thread 2826 JavaThread* main_thread = new JavaThread(); 2827 main_thread->set_thread_state(_thread_in_vm); 2828 // must do this before set_active_handles and initialize_thread_local_storage 2829 // Note: on solaris initialize_thread_local_storage() will (indirectly) 2830 // change the stack size recorded here to one based on the java thread 2831 // stacksize. This adjusted size is what is used to figure the placement 2832 // of the guard pages. 2833 main_thread->record_stack_base_and_size(); 2834 main_thread->initialize_thread_local_storage(); 2835 2836 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 2837 2838 if (!main_thread->set_as_starting_thread()) { 2839 vm_shutdown_during_initialization( 2840 "Failed necessary internal allocation. Out of swap space"); 2841 delete main_thread; 2842 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 2843 return JNI_ENOMEM; 2844 } 2845 2846 // Enable guard page *after* os::create_main_thread(), otherwise it would 2847 // crash Linux VM, see notes in os_linux.cpp. 2848 main_thread->create_stack_guard_pages(); 2849 2850 // Initialize Java-Leve synchronization subsystem 2851 ObjectSynchronizer::Initialize() ; 2852 2853 // Initialize global modules 2854 jint status = init_globals(); 2855 if (status != JNI_OK) { 2856 delete main_thread; 2857 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 2858 return status; 2859 } 2860 2861 HandleMark hm; 2862 2863 { MutexLocker mu(Threads_lock); 2864 Threads::add(main_thread); 2865 } 2866 2867 // Any JVMTI raw monitors entered in onload will transition into 2868 // real raw monitor. VM is setup enough here for raw monitor enter. 2869 JvmtiExport::transition_pending_onload_raw_monitors(); 2870 2871 if (VerifyBeforeGC && 2872 Universe::heap()->total_collections() >= VerifyGCStartAt) { 2873 Universe::heap()->prepare_for_verify(); 2874 Universe::verify(); // make sure we're starting with a clean slate 2875 } 2876 2877 // Create the VMThread 2878 { TraceTime timer("Start VMThread", TraceStartupTime); 2879 VMThread::create(); 2880 Thread* vmthread = VMThread::vm_thread(); 2881 2882 if (!os::create_thread(vmthread, os::vm_thread)) 2883 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 2884 2885 // Wait for the VM thread to become ready, and VMThread::run to initialize 2886 // Monitors can have spurious returns, must always check another state flag 2887 { 2888 MutexLocker ml(Notify_lock); 2889 os::start_thread(vmthread); 2890 while (vmthread->active_handles() == NULL) { 2891 Notify_lock->wait(); 2892 } 2893 } 2894 } 2895 2896 assert (Universe::is_fully_initialized(), "not initialized"); 2897 EXCEPTION_MARK; 2898 2899 // At this point, the Universe is initialized, but we have not executed 2900 // any byte code. Now is a good time (the only time) to dump out the 2901 // internal state of the JVM for sharing. 2902 2903 if (DumpSharedSpaces) { 2904 Universe::heap()->preload_and_dump(CHECK_0); 2905 ShouldNotReachHere(); 2906 } 2907 2908 // Always call even when there are not JVMTI environments yet, since environments 2909 // may be attached late and JVMTI must track phases of VM execution 2910 JvmtiExport::enter_start_phase(); 2911 2912 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 2913 JvmtiExport::post_vm_start(); 2914 2915 { 2916 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 2917 2918 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 2919 create_vm_init_libraries(); 2920 } 2921 2922 if (InitializeJavaLangString) { 2923 initialize_class(vmSymbolHandles::java_lang_String(), CHECK_0); 2924 } else { 2925 warning("java.lang.String not initialized"); 2926 } 2927 2928 if (AggressiveOpts) { 2929 // Forcibly initialize java/util/HashMap and mutate the private 2930 // static final "frontCacheEnabled" field before we start creating instances 2931#ifdef ASSERT 2932 klassOop tmp_k = SystemDictionary::find(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0); 2933 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 2934#endif 2935 klassOop k_o = SystemDictionary::resolve_or_null(vmSymbolHandles::java_util_HashMap(), Handle(), Handle(), CHECK_0); 2936 KlassHandle k = KlassHandle(THREAD, k_o); 2937 guarantee(k.not_null(), "Must find java/util/HashMap"); 2938 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 2939 ik->initialize(CHECK_0); 2940 fieldDescriptor fd; 2941 // Possible we might not find this field; if so, don't break 2942 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 2943 k()->bool_field_put(fd.offset(), true); 2944 } 2945 } 2946 2947 // Initialize java_lang.System (needed before creating the thread) 2948 if (InitializeJavaLangSystem) { 2949 initialize_class(vmSymbolHandles::java_lang_System(), CHECK_0); 2950 initialize_class(vmSymbolHandles::java_lang_ThreadGroup(), CHECK_0); 2951 Handle thread_group = create_initial_thread_group(CHECK_0); 2952 Universe::set_main_thread_group(thread_group()); 2953 initialize_class(vmSymbolHandles::java_lang_Thread(), CHECK_0); 2954 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 2955 main_thread->set_threadObj(thread_object); 2956 // Set thread status to running since main thread has 2957 // been started and running. 2958 java_lang_Thread::set_thread_status(thread_object, 2959 java_lang_Thread::RUNNABLE); 2960 2961 // The VM preresolve methods to these classes. Make sure that get initialized 2962 initialize_class(vmSymbolHandles::java_lang_reflect_Method(), CHECK_0); 2963 initialize_class(vmSymbolHandles::java_lang_ref_Finalizer(), CHECK_0); 2964 // The VM creates & returns objects of this class. Make sure it's initialized. 2965 initialize_class(vmSymbolHandles::java_lang_Class(), CHECK_0); 2966 call_initializeSystemClass(CHECK_0); 2967 } else { 2968 warning("java.lang.System not initialized"); 2969 } 2970 2971 // an instance of OutOfMemory exception has been allocated earlier 2972 if (InitializeJavaLangExceptionsErrors) { 2973 initialize_class(vmSymbolHandles::java_lang_OutOfMemoryError(), CHECK_0); 2974 initialize_class(vmSymbolHandles::java_lang_NullPointerException(), CHECK_0); 2975 initialize_class(vmSymbolHandles::java_lang_ClassCastException(), CHECK_0); 2976 initialize_class(vmSymbolHandles::java_lang_ArrayStoreException(), CHECK_0); 2977 initialize_class(vmSymbolHandles::java_lang_ArithmeticException(), CHECK_0); 2978 initialize_class(vmSymbolHandles::java_lang_StackOverflowError(), CHECK_0); 2979 initialize_class(vmSymbolHandles::java_lang_IllegalMonitorStateException(), CHECK_0); 2980 } else { 2981 warning("java.lang.OutOfMemoryError has not been initialized"); 2982 warning("java.lang.NullPointerException has not been initialized"); 2983 warning("java.lang.ClassCastException has not been initialized"); 2984 warning("java.lang.ArrayStoreException has not been initialized"); 2985 warning("java.lang.ArithmeticException has not been initialized"); 2986 warning("java.lang.StackOverflowError has not been initialized"); 2987 } 2988 } 2989 2990 // See : bugid 4211085. 2991 // Background : the static initializer of java.lang.Compiler tries to read 2992 // property"java.compiler" and read & write property "java.vm.info". 2993 // When a security manager is installed through the command line 2994 // option "-Djava.security.manager", the above properties are not 2995 // readable and the static initializer for java.lang.Compiler fails 2996 // resulting in a NoClassDefFoundError. This can happen in any 2997 // user code which calls methods in java.lang.Compiler. 2998 // Hack : the hack is to pre-load and initialize this class, so that only 2999 // system domains are on the stack when the properties are read. 3000 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3001 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3002 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3003 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3004 // Once that is done, we should remove this hack. 3005 initialize_class(vmSymbolHandles::java_lang_Compiler(), CHECK_0); 3006 3007 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3008 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3009 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3010 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3011 // This should also be taken out as soon as 4211383 gets fixed. 3012 reset_vm_info_property(CHECK_0); 3013 3014 quicken_jni_functions(); 3015 3016 // Set flag that basic initialization has completed. Used by exceptions and various 3017 // debug stuff, that does not work until all basic classes have been initialized. 3018 set_init_completed(); 3019 3020 HS_DTRACE_PROBE(hotspot, vm__init__end); 3021 3022 // record VM initialization completion time 3023 Management::record_vm_init_completed(); 3024 3025 // Compute system loader. Note that this has to occur after set_init_completed, since 3026 // valid exceptions may be thrown in the process. 3027 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3028 // set_init_completed has just been called, causing exceptions not to be shortcut 3029 // anymore. We call vm_exit_during_initialization directly instead. 3030 SystemDictionary::compute_java_system_loader(THREAD); 3031 if (HAS_PENDING_EXCEPTION) { 3032 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3033 } 3034 3035#ifndef SERIALGC 3036 // Support for ConcurrentMarkSweep. This should be cleaned up 3037 // and better encapsulated. XXX YSR 3038 if (UseConcMarkSweepGC) { 3039 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3040 if (HAS_PENDING_EXCEPTION) { 3041 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3042 } 3043 } 3044#endif // SERIALGC 3045 3046 // Always call even when there are not JVMTI environments yet, since environments 3047 // may be attached late and JVMTI must track phases of VM execution 3048 JvmtiExport::enter_live_phase(); 3049 3050 // Signal Dispatcher needs to be started before VMInit event is posted 3051 os::signal_init(); 3052 3053 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3054 if (!DisableAttachMechanism) { 3055 if (StartAttachListener || AttachListener::init_at_startup()) { 3056 AttachListener::init(); 3057 } 3058 } 3059 3060 // Launch -Xrun agents 3061 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3062 // back-end can launch with -Xdebug -Xrunjdwp. 3063 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3064 create_vm_init_libraries(); 3065 } 3066 3067 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3068 JvmtiExport::post_vm_initialized(); 3069 3070 Chunk::start_chunk_pool_cleaner_task(); 3071 3072 // initialize compiler(s) 3073 CompileBroker::compilation_init(); 3074 3075 Management::initialize(THREAD); 3076 if (HAS_PENDING_EXCEPTION) { 3077 // management agent fails to start possibly due to 3078 // configuration problem and is responsible for printing 3079 // stack trace if appropriate. Simply exit VM. 3080 vm_exit(1); 3081 } 3082 3083 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3084 if (Arguments::has_alloc_profile()) AllocationProfiler::engage(); 3085 if (MemProfiling) MemProfiler::engage(); 3086 StatSampler::engage(); 3087 if (CheckJNICalls) JniPeriodicChecker::engage(); 3088 3089 BiasedLocking::init(); 3090 3091 3092 // Start up the WatcherThread if there are any periodic tasks 3093 // NOTE: All PeriodicTasks should be registered by now. If they 3094 // aren't, late joiners might appear to start slowly (we might 3095 // take a while to process their first tick). 3096 if (PeriodicTask::num_tasks() > 0) { 3097 WatcherThread::start(); 3098 } 3099 3100 create_vm_timer.end(); 3101 return JNI_OK; 3102} 3103 3104// type for the Agent_OnLoad and JVM_OnLoad entry points 3105extern "C" { 3106 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3107} 3108// Find a command line agent library and return its entry point for 3109// -agentlib: -agentpath: -Xrun 3110// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3111static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3112 OnLoadEntry_t on_load_entry = NULL; 3113 void *library = agent->os_lib(); // check if we have looked it up before 3114 3115 if (library == NULL) { 3116 char buffer[JVM_MAXPATHLEN]; 3117 char ebuf[1024]; 3118 const char *name = agent->name(); 3119 3120 if (agent->is_absolute_path()) { 3121 library = hpi::dll_load(name, ebuf, sizeof ebuf); 3122 if (library == NULL) { 3123 // If we can't find the agent, exit. 3124 vm_exit_during_initialization("Could not find agent library in absolute path", name); 3125 } 3126 } else { 3127 // Try to load the agent from the standard dll directory 3128 hpi::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name); 3129 library = hpi::dll_load(buffer, ebuf, sizeof ebuf); 3130#ifdef KERNEL 3131 // Download instrument dll 3132 if (library == NULL && strcmp(name, "instrument") == 0) { 3133 char *props = Arguments::get_kernel_properties(); 3134 char *home = Arguments::get_java_home(); 3135 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false" 3136 " sun.jkernel.DownloadManager -download client_jvm"; 3137 int length = strlen(props) + strlen(home) + strlen(fmt) + 1; 3138 char *cmd = AllocateHeap(length); 3139 jio_snprintf(cmd, length, fmt, home, props); 3140 int status = os::fork_and_exec(cmd); 3141 FreeHeap(props); 3142 FreeHeap(cmd); 3143 if (status == -1) { 3144 warning(cmd); 3145 vm_exit_during_initialization("fork_and_exec failed: %s", 3146 strerror(errno)); 3147 } 3148 // when this comes back the instrument.dll should be where it belongs. 3149 library = hpi::dll_load(buffer, ebuf, sizeof ebuf); 3150 } 3151#endif // KERNEL 3152 if (library == NULL) { // Try the local directory 3153 char ns[1] = {0}; 3154 hpi::dll_build_name(buffer, sizeof(buffer), ns, name); 3155 library = hpi::dll_load(buffer, ebuf, sizeof ebuf); 3156 if (library == NULL) { 3157 // If we can't find the agent, exit. 3158 vm_exit_during_initialization("Could not find agent library on the library path or in the local directory", name); 3159 } 3160 } 3161 } 3162 agent->set_os_lib(library); 3163 } 3164 3165 // Find the OnLoad function. 3166 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3167 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, hpi::dll_lookup(library, on_load_symbols[symbol_index])); 3168 if (on_load_entry != NULL) break; 3169 } 3170 return on_load_entry; 3171} 3172 3173// Find the JVM_OnLoad entry point 3174static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3175 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3176 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3177} 3178 3179// Find the Agent_OnLoad entry point 3180static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3181 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3182 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3183} 3184 3185// For backwards compatibility with -Xrun 3186// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3187// treated like -agentpath: 3188// Must be called before agent libraries are created 3189void Threads::convert_vm_init_libraries_to_agents() { 3190 AgentLibrary* agent; 3191 AgentLibrary* next; 3192 3193 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3194 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3195 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3196 3197 // If there is an JVM_OnLoad function it will get called later, 3198 // otherwise see if there is an Agent_OnLoad 3199 if (on_load_entry == NULL) { 3200 on_load_entry = lookup_agent_on_load(agent); 3201 if (on_load_entry != NULL) { 3202 // switch it to the agent list -- so that Agent_OnLoad will be called, 3203 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3204 Arguments::convert_library_to_agent(agent); 3205 } else { 3206 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3207 } 3208 } 3209 } 3210} 3211 3212// Create agents for -agentlib: -agentpath: and converted -Xrun 3213// Invokes Agent_OnLoad 3214// Called very early -- before JavaThreads exist 3215void Threads::create_vm_init_agents() { 3216 extern struct JavaVM_ main_vm; 3217 AgentLibrary* agent; 3218 3219 JvmtiExport::enter_onload_phase(); 3220 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3221 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3222 3223 if (on_load_entry != NULL) { 3224 // Invoke the Agent_OnLoad function 3225 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3226 if (err != JNI_OK) { 3227 vm_exit_during_initialization("agent library failed to init", agent->name()); 3228 } 3229 } else { 3230 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3231 } 3232 } 3233 JvmtiExport::enter_primordial_phase(); 3234} 3235 3236extern "C" { 3237 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3238} 3239 3240void Threads::shutdown_vm_agents() { 3241 // Send any Agent_OnUnload notifications 3242 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3243 extern struct JavaVM_ main_vm; 3244 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3245 3246 // Find the Agent_OnUnload function. 3247 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3248 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3249 hpi::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3250 3251 // Invoke the Agent_OnUnload function 3252 if (unload_entry != NULL) { 3253 JavaThread* thread = JavaThread::current(); 3254 ThreadToNativeFromVM ttn(thread); 3255 HandleMark hm(thread); 3256 (*unload_entry)(&main_vm); 3257 break; 3258 } 3259 } 3260 } 3261} 3262 3263// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3264// Invokes JVM_OnLoad 3265void Threads::create_vm_init_libraries() { 3266 extern struct JavaVM_ main_vm; 3267 AgentLibrary* agent; 3268 3269 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3270 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3271 3272 if (on_load_entry != NULL) { 3273 // Invoke the JVM_OnLoad function 3274 JavaThread* thread = JavaThread::current(); 3275 ThreadToNativeFromVM ttn(thread); 3276 HandleMark hm(thread); 3277 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3278 if (err != JNI_OK) { 3279 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3280 } 3281 } else { 3282 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3283 } 3284 } 3285} 3286 3287// Last thread running calls java.lang.Shutdown.shutdown() 3288void JavaThread::invoke_shutdown_hooks() { 3289 HandleMark hm(this); 3290 3291 // We could get here with a pending exception, if so clear it now. 3292 if (this->has_pending_exception()) { 3293 this->clear_pending_exception(); 3294 } 3295 3296 EXCEPTION_MARK; 3297 klassOop k = 3298 SystemDictionary::resolve_or_null(vmSymbolHandles::java_lang_Shutdown(), 3299 THREAD); 3300 if (k != NULL) { 3301 // SystemDictionary::resolve_or_null will return null if there was 3302 // an exception. If we cannot load the Shutdown class, just don't 3303 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3304 // and finalizers (if runFinalizersOnExit is set) won't be run. 3305 // Note that if a shutdown hook was registered or runFinalizersOnExit 3306 // was called, the Shutdown class would have already been loaded 3307 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3308 instanceKlassHandle shutdown_klass (THREAD, k); 3309 JavaValue result(T_VOID); 3310 JavaCalls::call_static(&result, 3311 shutdown_klass, 3312 vmSymbolHandles::shutdown_method_name(), 3313 vmSymbolHandles::void_method_signature(), 3314 THREAD); 3315 } 3316 CLEAR_PENDING_EXCEPTION; 3317} 3318 3319// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3320// the program falls off the end of main(). Another VM exit path is through 3321// vm_exit() when the program calls System.exit() to return a value or when 3322// there is a serious error in VM. The two shutdown paths are not exactly 3323// the same, but they share Shutdown.shutdown() at Java level and before_exit() 3324// and VM_Exit op at VM level. 3325// 3326// Shutdown sequence: 3327// + Wait until we are the last non-daemon thread to execute 3328// <-- every thing is still working at this moment --> 3329// + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3330// shutdown hooks, run finalizers if finalization-on-exit 3331// + Call before_exit(), prepare for VM exit 3332// > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3333// currently the only user of this mechanism is File.deleteOnExit()) 3334// > stop flat profiler, StatSampler, watcher thread, CMS threads, 3335// post thread end and vm death events to JVMTI, 3336// stop signal thread 3337// + Call JavaThread::exit(), it will: 3338// > release JNI handle blocks, remove stack guard pages 3339// > remove this thread from Threads list 3340// <-- no more Java code from this thread after this point --> 3341// + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3342// the compiler threads at safepoint 3343// <-- do not use anything that could get blocked by Safepoint --> 3344// + Disable tracing at JNI/JVM barriers 3345// + Set _vm_exited flag for threads that are still running native code 3346// + Delete this thread 3347// + Call exit_globals() 3348// > deletes tty 3349// > deletes PerfMemory resources 3350// + Return to caller 3351 3352bool Threads::destroy_vm() { 3353 JavaThread* thread = JavaThread::current(); 3354 3355 // Wait until we are the last non-daemon thread to execute 3356 { MutexLocker nu(Threads_lock); 3357 while (Threads::number_of_non_daemon_threads() > 1 ) 3358 // This wait should make safepoint checks, wait without a timeout, 3359 // and wait as a suspend-equivalent condition. 3360 // 3361 // Note: If the FlatProfiler is running and this thread is waiting 3362 // for another non-daemon thread to finish, then the FlatProfiler 3363 // is waiting for the external suspend request on this thread to 3364 // complete. wait_for_ext_suspend_completion() will eventually 3365 // timeout, but that takes time. Making this wait a suspend- 3366 // equivalent condition solves that timeout problem. 3367 // 3368 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3369 Mutex::_as_suspend_equivalent_flag); 3370 } 3371 3372 // Hang forever on exit if we are reporting an error. 3373 if (ShowMessageBoxOnError && is_error_reported()) { 3374 os::infinite_sleep(); 3375 } 3376 3377 if (JDK_Version::is_jdk12x_version()) { 3378 // We are the last thread running, so check if finalizers should be run. 3379 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3380 HandleMark rm(thread); 3381 Universe::run_finalizers_on_exit(); 3382 } else { 3383 // run Java level shutdown hooks 3384 thread->invoke_shutdown_hooks(); 3385 } 3386 3387 before_exit(thread); 3388 3389 thread->exit(true); 3390 3391 // Stop VM thread. 3392 { 3393 // 4945125 The vm thread comes to a safepoint during exit. 3394 // GC vm_operations can get caught at the safepoint, and the 3395 // heap is unparseable if they are caught. Grab the Heap_lock 3396 // to prevent this. The GC vm_operations will not be able to 3397 // queue until after the vm thread is dead. 3398 MutexLocker ml(Heap_lock); 3399 3400 VMThread::wait_for_vm_thread_exit(); 3401 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3402 VMThread::destroy(); 3403 } 3404 3405 // clean up ideal graph printers 3406#if defined(COMPILER2) && !defined(PRODUCT) 3407 IdealGraphPrinter::clean_up(); 3408#endif 3409 3410 // Now, all Java threads are gone except daemon threads. Daemon threads 3411 // running Java code or in VM are stopped by the Safepoint. However, 3412 // daemon threads executing native code are still running. But they 3413 // will be stopped at native=>Java/VM barriers. Note that we can't 3414 // simply kill or suspend them, as it is inherently deadlock-prone. 3415 3416#ifndef PRODUCT 3417 // disable function tracing at JNI/JVM barriers 3418 TraceHPI = false; 3419 TraceJNICalls = false; 3420 TraceJVMCalls = false; 3421 TraceRuntimeCalls = false; 3422#endif 3423 3424 VM_Exit::set_vm_exited(); 3425 3426 notify_vm_shutdown(); 3427 3428 delete thread; 3429 3430 // exit_globals() will delete tty 3431 exit_globals(); 3432 3433 return true; 3434} 3435 3436 3437jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 3438 if (version == JNI_VERSION_1_1) return JNI_TRUE; 3439 return is_supported_jni_version(version); 3440} 3441 3442 3443jboolean Threads::is_supported_jni_version(jint version) { 3444 if (version == JNI_VERSION_1_2) return JNI_TRUE; 3445 if (version == JNI_VERSION_1_4) return JNI_TRUE; 3446 if (version == JNI_VERSION_1_6) return JNI_TRUE; 3447 return JNI_FALSE; 3448} 3449 3450 3451void Threads::add(JavaThread* p, bool force_daemon) { 3452 // The threads lock must be owned at this point 3453 assert_locked_or_safepoint(Threads_lock); 3454 p->set_next(_thread_list); 3455 _thread_list = p; 3456 _number_of_threads++; 3457 oop threadObj = p->threadObj(); 3458 bool daemon = true; 3459 // Bootstrapping problem: threadObj can be null for initial 3460 // JavaThread (or for threads attached via JNI) 3461 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 3462 _number_of_non_daemon_threads++; 3463 daemon = false; 3464 } 3465 3466 ThreadService::add_thread(p, daemon); 3467 3468 // Possible GC point. 3469 Events::log("Thread added: " INTPTR_FORMAT, p); 3470} 3471 3472void Threads::remove(JavaThread* p) { 3473 // Extra scope needed for Thread_lock, so we can check 3474 // that we do not remove thread without safepoint code notice 3475 { MutexLocker ml(Threads_lock); 3476 3477 assert(includes(p), "p must be present"); 3478 3479 JavaThread* current = _thread_list; 3480 JavaThread* prev = NULL; 3481 3482 while (current != p) { 3483 prev = current; 3484 current = current->next(); 3485 } 3486 3487 if (prev) { 3488 prev->set_next(current->next()); 3489 } else { 3490 _thread_list = p->next(); 3491 } 3492 _number_of_threads--; 3493 oop threadObj = p->threadObj(); 3494 bool daemon = true; 3495 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 3496 _number_of_non_daemon_threads--; 3497 daemon = false; 3498 3499 // Only one thread left, do a notify on the Threads_lock so a thread waiting 3500 // on destroy_vm will wake up. 3501 if (number_of_non_daemon_threads() == 1) 3502 Threads_lock->notify_all(); 3503 } 3504 ThreadService::remove_thread(p, daemon); 3505 3506 // Make sure that safepoint code disregard this thread. This is needed since 3507 // the thread might mess around with locks after this point. This can cause it 3508 // to do callbacks into the safepoint code. However, the safepoint code is not aware 3509 // of this thread since it is removed from the queue. 3510 p->set_terminated_value(); 3511 } // unlock Threads_lock 3512 3513 // Since Events::log uses a lock, we grab it outside the Threads_lock 3514 Events::log("Thread exited: " INTPTR_FORMAT, p); 3515} 3516 3517// Threads_lock must be held when this is called (or must be called during a safepoint) 3518bool Threads::includes(JavaThread* p) { 3519 assert(Threads_lock->is_locked(), "sanity check"); 3520 ALL_JAVA_THREADS(q) { 3521 if (q == p ) { 3522 return true; 3523 } 3524 } 3525 return false; 3526} 3527 3528// Operations on the Threads list for GC. These are not explicitly locked, 3529// but the garbage collector must provide a safe context for them to run. 3530// In particular, these things should never be called when the Threads_lock 3531// is held by some other thread. (Note: the Safepoint abstraction also 3532// uses the Threads_lock to gurantee this property. It also makes sure that 3533// all threads gets blocked when exiting or starting). 3534 3535void Threads::oops_do(OopClosure* f) { 3536 ALL_JAVA_THREADS(p) { 3537 p->oops_do(f); 3538 } 3539 VMThread::vm_thread()->oops_do(f); 3540} 3541 3542void Threads::possibly_parallel_oops_do(OopClosure* f) { 3543 // Introduce a mechanism allowing parallel threads to claim threads as 3544 // root groups. Overhead should be small enough to use all the time, 3545 // even in sequential code. 3546 SharedHeap* sh = SharedHeap::heap(); 3547 bool is_par = (sh->n_par_threads() > 0); 3548 int cp = SharedHeap::heap()->strong_roots_parity(); 3549 ALL_JAVA_THREADS(p) { 3550 if (p->claim_oops_do(is_par, cp)) { 3551 p->oops_do(f); 3552 } 3553 } 3554 VMThread* vmt = VMThread::vm_thread(); 3555 if (vmt->claim_oops_do(is_par, cp)) 3556 vmt->oops_do(f); 3557} 3558 3559#ifndef SERIALGC 3560// Used by ParallelScavenge 3561void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 3562 ALL_JAVA_THREADS(p) { 3563 q->enqueue(new ThreadRootsTask(p)); 3564 } 3565 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 3566} 3567 3568// Used by Parallel Old 3569void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 3570 ALL_JAVA_THREADS(p) { 3571 q->enqueue(new ThreadRootsMarkingTask(p)); 3572 } 3573 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 3574} 3575#endif // SERIALGC 3576 3577void Threads::nmethods_do() { 3578 ALL_JAVA_THREADS(p) { 3579 p->nmethods_do(); 3580 } 3581 VMThread::vm_thread()->nmethods_do(); 3582} 3583 3584void Threads::gc_epilogue() { 3585 ALL_JAVA_THREADS(p) { 3586 p->gc_epilogue(); 3587 } 3588} 3589 3590void Threads::gc_prologue() { 3591 ALL_JAVA_THREADS(p) { 3592 p->gc_prologue(); 3593 } 3594} 3595 3596void Threads::deoptimized_wrt_marked_nmethods() { 3597 ALL_JAVA_THREADS(p) { 3598 p->deoptimized_wrt_marked_nmethods(); 3599 } 3600} 3601 3602 3603// Get count Java threads that are waiting to enter the specified monitor. 3604GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 3605 address monitor, bool doLock) { 3606 assert(doLock || SafepointSynchronize::is_at_safepoint(), 3607 "must grab Threads_lock or be at safepoint"); 3608 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 3609 3610 int i = 0; 3611 { 3612 MutexLockerEx ml(doLock ? Threads_lock : NULL); 3613 ALL_JAVA_THREADS(p) { 3614 if (p->is_Compiler_thread()) continue; 3615 3616 address pending = (address)p->current_pending_monitor(); 3617 if (pending == monitor) { // found a match 3618 if (i < count) result->append(p); // save the first count matches 3619 i++; 3620 } 3621 } 3622 } 3623 return result; 3624} 3625 3626 3627JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 3628 assert(doLock || 3629 Threads_lock->owned_by_self() || 3630 SafepointSynchronize::is_at_safepoint(), 3631 "must grab Threads_lock or be at safepoint"); 3632 3633 // NULL owner means not locked so we can skip the search 3634 if (owner == NULL) return NULL; 3635 3636 { 3637 MutexLockerEx ml(doLock ? Threads_lock : NULL); 3638 ALL_JAVA_THREADS(p) { 3639 // first, see if owner is the address of a Java thread 3640 if (owner == (address)p) return p; 3641 } 3642 } 3643 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled"); 3644 if (UseHeavyMonitors) return NULL; 3645 3646 // 3647 // If we didn't find a matching Java thread and we didn't force use of 3648 // heavyweight monitors, then the owner is the stack address of the 3649 // Lock Word in the owning Java thread's stack. 3650 // 3651 // We can't use Thread::is_lock_owned() or Thread::lock_is_in_stack() because 3652 // those routines rely on the "current" stack pointer. That would be our 3653 // stack pointer which is not relevant to the question. Instead we use the 3654 // highest lock ever entered by the thread and find the thread that is 3655 // higher than and closest to our target stack address. 3656 // 3657 address least_diff = 0; 3658 bool least_diff_initialized = false; 3659 JavaThread* the_owner = NULL; 3660 { 3661 MutexLockerEx ml(doLock ? Threads_lock : NULL); 3662 ALL_JAVA_THREADS(q) { 3663 address addr = q->highest_lock(); 3664 if (addr == NULL || addr < owner) continue; // thread has entered no monitors or is too low 3665 address diff = (address)(addr - owner); 3666 if (!least_diff_initialized || diff < least_diff) { 3667 least_diff_initialized = true; 3668 least_diff = diff; 3669 the_owner = q; 3670 } 3671 } 3672 } 3673 assert(the_owner != NULL, "Did not find owning Java thread for lock word address"); 3674 return the_owner; 3675} 3676 3677// Threads::print_on() is called at safepoint by VM_PrintThreads operation. 3678void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 3679 char buf[32]; 3680 st->print_cr(os::local_time_string(buf, sizeof(buf))); 3681 3682 st->print_cr("Full thread dump %s (%s %s):", 3683 Abstract_VM_Version::vm_name(), 3684 Abstract_VM_Version::vm_release(), 3685 Abstract_VM_Version::vm_info_string() 3686 ); 3687 st->cr(); 3688 3689#ifndef SERIALGC 3690 // Dump concurrent locks 3691 ConcurrentLocksDump concurrent_locks; 3692 if (print_concurrent_locks) { 3693 concurrent_locks.dump_at_safepoint(); 3694 } 3695#endif // SERIALGC 3696 3697 ALL_JAVA_THREADS(p) { 3698 ResourceMark rm; 3699 p->print_on(st); 3700 if (print_stacks) { 3701 if (internal_format) { 3702 p->trace_stack(); 3703 } else { 3704 p->print_stack_on(st); 3705 } 3706 } 3707 st->cr(); 3708#ifndef SERIALGC 3709 if (print_concurrent_locks) { 3710 concurrent_locks.print_locks_on(p, st); 3711 } 3712#endif // SERIALGC 3713 } 3714 3715 VMThread::vm_thread()->print_on(st); 3716 st->cr(); 3717 Universe::heap()->print_gc_threads_on(st); 3718 WatcherThread* wt = WatcherThread::watcher_thread(); 3719 if (wt != NULL) wt->print_on(st); 3720 st->cr(); 3721 CompileBroker::print_compiler_threads_on(st); 3722 st->flush(); 3723} 3724 3725// Threads::print_on_error() is called by fatal error handler. It's possible 3726// that VM is not at safepoint and/or current thread is inside signal handler. 3727// Don't print stack trace, as the stack may not be walkable. Don't allocate 3728// memory (even in resource area), it might deadlock the error handler. 3729void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 3730 bool found_current = false; 3731 st->print_cr("Java Threads: ( => current thread )"); 3732 ALL_JAVA_THREADS(thread) { 3733 bool is_current = (current == thread); 3734 found_current = found_current || is_current; 3735 3736 st->print("%s", is_current ? "=>" : " "); 3737 3738 st->print(PTR_FORMAT, thread); 3739 st->print(" "); 3740 thread->print_on_error(st, buf, buflen); 3741 st->cr(); 3742 } 3743 st->cr(); 3744 3745 st->print_cr("Other Threads:"); 3746 if (VMThread::vm_thread()) { 3747 bool is_current = (current == VMThread::vm_thread()); 3748 found_current = found_current || is_current; 3749 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 3750 3751 st->print(PTR_FORMAT, VMThread::vm_thread()); 3752 st->print(" "); 3753 VMThread::vm_thread()->print_on_error(st, buf, buflen); 3754 st->cr(); 3755 } 3756 WatcherThread* wt = WatcherThread::watcher_thread(); 3757 if (wt != NULL) { 3758 bool is_current = (current == wt); 3759 found_current = found_current || is_current; 3760 st->print("%s", is_current ? "=>" : " "); 3761 3762 st->print(PTR_FORMAT, wt); 3763 st->print(" "); 3764 wt->print_on_error(st, buf, buflen); 3765 st->cr(); 3766 } 3767 if (!found_current) { 3768 st->cr(); 3769 st->print("=>" PTR_FORMAT " (exited) ", current); 3770 current->print_on_error(st, buf, buflen); 3771 st->cr(); 3772 } 3773} 3774 3775 3776// Lifecycle management for TSM ParkEvents. 3777// ParkEvents are type-stable (TSM). 3778// In our particular implementation they happen to be immortal. 3779// 3780// We manage concurrency on the FreeList with a CAS-based 3781// detach-modify-reattach idiom that avoids the ABA problems 3782// that would otherwise be present in a simple CAS-based 3783// push-pop implementation. (push-one and pop-all) 3784// 3785// Caveat: Allocate() and Release() may be called from threads 3786// other than the thread associated with the Event! 3787// If we need to call Allocate() when running as the thread in 3788// question then look for the PD calls to initialize native TLS. 3789// Native TLS (Win32/Linux/Solaris) can only be initialized or 3790// accessed by the associated thread. 3791// See also pd_initialize(). 3792// 3793// Note that we could defer associating a ParkEvent with a thread 3794// until the 1st time the thread calls park(). unpark() calls to 3795// an unprovisioned thread would be ignored. The first park() call 3796// for a thread would allocate and associate a ParkEvent and return 3797// immediately. 3798 3799volatile int ParkEvent::ListLock = 0 ; 3800ParkEvent * volatile ParkEvent::FreeList = NULL ; 3801 3802ParkEvent * ParkEvent::Allocate (Thread * t) { 3803 // In rare cases -- JVM_RawMonitor* operations -- we can find t == null. 3804 ParkEvent * ev ; 3805 3806 // Start by trying to recycle an existing but unassociated 3807 // ParkEvent from the global free list. 3808 for (;;) { 3809 ev = FreeList ; 3810 if (ev == NULL) break ; 3811 // 1: Detach - sequester or privatize the list 3812 // Tantamount to ev = Swap (&FreeList, NULL) 3813 if (Atomic::cmpxchg_ptr (NULL, &FreeList, ev) != ev) { 3814 continue ; 3815 } 3816 3817 // We've detached the list. The list in-hand is now 3818 // local to this thread. This thread can operate on the 3819 // list without risk of interference from other threads. 3820 // 2: Extract -- pop the 1st element from the list. 3821 ParkEvent * List = ev->FreeNext ; 3822 if (List == NULL) break ; 3823 for (;;) { 3824 // 3: Try to reattach the residual list 3825 guarantee (List != NULL, "invariant") ; 3826 ParkEvent * Arv = (ParkEvent *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ; 3827 if (Arv == NULL) break ; 3828 3829 // New nodes arrived. Try to detach the recent arrivals. 3830 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) { 3831 continue ; 3832 } 3833 guarantee (Arv != NULL, "invariant") ; 3834 // 4: Merge Arv into List 3835 ParkEvent * Tail = List ; 3836 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ; 3837 Tail->FreeNext = Arv ; 3838 } 3839 break ; 3840 } 3841 3842 if (ev != NULL) { 3843 guarantee (ev->AssociatedWith == NULL, "invariant") ; 3844 } else { 3845 // Do this the hard way -- materialize a new ParkEvent. 3846 // In rare cases an allocating thread might detach a long list -- 3847 // installing null into FreeList -- and then stall or be obstructed. 3848 // A 2nd thread calling Allocate() would see FreeList == null. 3849 // The list held privately by the 1st thread is unavailable to the 2nd thread. 3850 // In that case the 2nd thread would have to materialize a new ParkEvent, 3851 // even though free ParkEvents existed in the system. In this case we end up 3852 // with more ParkEvents in circulation than we need, but the race is 3853 // rare and the outcome is benign. Ideally, the # of extant ParkEvents 3854 // is equal to the maximum # of threads that existed at any one time. 3855 // Because of the race mentioned above, segments of the freelist 3856 // can be transiently inaccessible. At worst we may end up with the 3857 // # of ParkEvents in circulation slightly above the ideal. 3858 // Note that if we didn't have the TSM/immortal constraint, then 3859 // when reattaching, above, we could trim the list. 3860 ev = new ParkEvent () ; 3861 guarantee ((intptr_t(ev) & 0xFF) == 0, "invariant") ; 3862 } 3863 ev->reset() ; // courtesy to caller 3864 ev->AssociatedWith = t ; // Associate ev with t 3865 ev->FreeNext = NULL ; 3866 return ev ; 3867} 3868 3869void ParkEvent::Release (ParkEvent * ev) { 3870 if (ev == NULL) return ; 3871 guarantee (ev->FreeNext == NULL , "invariant") ; 3872 ev->AssociatedWith = NULL ; 3873 for (;;) { 3874 // Push ev onto FreeList 3875 // The mechanism is "half" lock-free. 3876 ParkEvent * List = FreeList ; 3877 ev->FreeNext = List ; 3878 if (Atomic::cmpxchg_ptr (ev, &FreeList, List) == List) break ; 3879 } 3880} 3881 3882// Override operator new and delete so we can ensure that the 3883// least significant byte of ParkEvent addresses is 0. 3884// Beware that excessive address alignment is undesirable 3885// as it can result in D$ index usage imbalance as 3886// well as bank access imbalance on Niagara-like platforms, 3887// although Niagara's hash function should help. 3888 3889void * ParkEvent::operator new (size_t sz) { 3890 return (void *) ((intptr_t (CHeapObj::operator new (sz + 256)) + 256) & -256) ; 3891} 3892 3893void ParkEvent::operator delete (void * a) { 3894 // ParkEvents are type-stable and immortal ... 3895 ShouldNotReachHere(); 3896} 3897 3898 3899// 6399321 As a temporary measure we copied & modified the ParkEvent:: 3900// allocate() and release() code for use by Parkers. The Parker:: forms 3901// will eventually be removed as we consolide and shift over to ParkEvents 3902// for both builtin synchronization and JSR166 operations. 3903 3904volatile int Parker::ListLock = 0 ; 3905Parker * volatile Parker::FreeList = NULL ; 3906 3907Parker * Parker::Allocate (JavaThread * t) { 3908 guarantee (t != NULL, "invariant") ; 3909 Parker * p ; 3910 3911 // Start by trying to recycle an existing but unassociated 3912 // Parker from the global free list. 3913 for (;;) { 3914 p = FreeList ; 3915 if (p == NULL) break ; 3916 // 1: Detach 3917 // Tantamount to p = Swap (&FreeList, NULL) 3918 if (Atomic::cmpxchg_ptr (NULL, &FreeList, p) != p) { 3919 continue ; 3920 } 3921 3922 // We've detached the list. The list in-hand is now 3923 // local to this thread. This thread can operate on the 3924 // list without risk of interference from other threads. 3925 // 2: Extract -- pop the 1st element from the list. 3926 Parker * List = p->FreeNext ; 3927 if (List == NULL) break ; 3928 for (;;) { 3929 // 3: Try to reattach the residual list 3930 guarantee (List != NULL, "invariant") ; 3931 Parker * Arv = (Parker *) Atomic::cmpxchg_ptr (List, &FreeList, NULL) ; 3932 if (Arv == NULL) break ; 3933 3934 // New nodes arrived. Try to detach the recent arrivals. 3935 if (Atomic::cmpxchg_ptr (NULL, &FreeList, Arv) != Arv) { 3936 continue ; 3937 } 3938 guarantee (Arv != NULL, "invariant") ; 3939 // 4: Merge Arv into List 3940 Parker * Tail = List ; 3941 while (Tail->FreeNext != NULL) Tail = Tail->FreeNext ; 3942 Tail->FreeNext = Arv ; 3943 } 3944 break ; 3945 } 3946 3947 if (p != NULL) { 3948 guarantee (p->AssociatedWith == NULL, "invariant") ; 3949 } else { 3950 // Do this the hard way -- materialize a new Parker.. 3951 // In rare cases an allocating thread might detach 3952 // a long list -- installing null into FreeList --and 3953 // then stall. Another thread calling Allocate() would see 3954 // FreeList == null and then invoke the ctor. In this case we 3955 // end up with more Parkers in circulation than we need, but 3956 // the race is rare and the outcome is benign. 3957 // Ideally, the # of extant Parkers is equal to the 3958 // maximum # of threads that existed at any one time. 3959 // Because of the race mentioned above, segments of the 3960 // freelist can be transiently inaccessible. At worst 3961 // we may end up with the # of Parkers in circulation 3962 // slightly above the ideal. 3963 p = new Parker() ; 3964 } 3965 p->AssociatedWith = t ; // Associate p with t 3966 p->FreeNext = NULL ; 3967 return p ; 3968} 3969 3970 3971void Parker::Release (Parker * p) { 3972 if (p == NULL) return ; 3973 guarantee (p->AssociatedWith != NULL, "invariant") ; 3974 guarantee (p->FreeNext == NULL , "invariant") ; 3975 p->AssociatedWith = NULL ; 3976 for (;;) { 3977 // Push p onto FreeList 3978 Parker * List = FreeList ; 3979 p->FreeNext = List ; 3980 if (Atomic::cmpxchg_ptr (p, &FreeList, List) == List) break ; 3981 } 3982} 3983 3984void Threads::verify() { 3985 ALL_JAVA_THREADS(p) { 3986 p->verify(); 3987 } 3988 VMThread* thread = VMThread::vm_thread(); 3989 if (thread != NULL) thread->verify(); 3990} 3991