1 /* 2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "jvm.h" 27 #include "aot/aotLoader.hpp" 28 #include "classfile/classLoader.hpp" 29 #include "classfile/javaClasses.hpp" 30 #include "classfile/moduleEntry.hpp" 31 #include "classfile/systemDictionary.hpp" 32 #include "classfile/vmSymbols.hpp" 33 #include "code/codeCache.hpp" 34 #include "code/scopeDesc.hpp" 35 #include "compiler/compileBroker.hpp" 36 #include "compiler/compileTask.hpp" 37 #include "gc/shared/barrierSet.hpp" 38 #include "gc/shared/gcId.hpp" 39 #include "gc/shared/gcLocker.inline.hpp" 40 #include "gc/shared/workgroup.hpp" 41 #include "interpreter/interpreter.hpp" 42 #include "interpreter/linkResolver.hpp" 43 #include "interpreter/oopMapCache.hpp" 44 #include "jfr/jfrEvents.hpp" 45 #include "jvmtifiles/jvmtiEnv.hpp" 46 #include "logging/log.hpp" 47 #include "logging/logConfiguration.hpp" 48 #include "logging/logStream.hpp" 49 #include "memory/allocation.inline.hpp" 50 #include "memory/iterator.hpp" 51 #include "memory/metaspaceShared.hpp" 52 #include "memory/oopFactory.hpp" 53 #include "memory/resourceArea.hpp" 54 #include "memory/universe.hpp" 55 #include "oops/access.inline.hpp" 56 #include "oops/instanceKlass.hpp" 57 #include "oops/objArrayOop.hpp" 58 #include "oops/oop.inline.hpp" 59 #include "oops/symbol.hpp" 60 #include "oops/typeArrayOop.inline.hpp" 61 #include "oops/verifyOopClosure.hpp" 62 #include "prims/jvm_misc.hpp" 63 #include "prims/jvmtiExport.hpp" 64 #include "prims/jvmtiThreadState.hpp" 65 #include "runtime/arguments.hpp" 66 #include "runtime/atomic.hpp" 67 #include "runtime/biasedLocking.hpp" 68 #include "runtime/fieldDescriptor.inline.hpp" 69 #include "runtime/flags/jvmFlagConstraintList.hpp" 70 #include "runtime/flags/jvmFlagRangeList.hpp" 71 #include "runtime/deoptimization.hpp" 72 #include "runtime/frame.inline.hpp" 73 #include "runtime/handles.inline.hpp" 74 #include "runtime/handshake.hpp" 75 #include "runtime/init.hpp" 76 #include "runtime/interfaceSupport.inline.hpp" 77 #include "runtime/java.hpp" 78 #include "runtime/javaCalls.hpp" 79 #include "runtime/jniHandles.inline.hpp" 80 #include "runtime/jniPeriodicChecker.hpp" 81 #include "runtime/memprofiler.hpp" 82 #include "runtime/mutexLocker.hpp" 83 #include "runtime/objectMonitor.hpp" 84 #include "runtime/orderAccess.hpp" 85 #include "runtime/osThread.hpp" 86 #include "runtime/prefetch.inline.hpp" 87 #include "runtime/safepoint.hpp" 88 #include "runtime/safepointMechanism.inline.hpp" 89 #include "runtime/safepointVerifiers.hpp" 90 #include "runtime/serviceThread.hpp" 91 #include "runtime/sharedRuntime.hpp" 92 #include "runtime/statSampler.hpp" 93 #include "runtime/stubRoutines.hpp" 94 #include "runtime/sweeper.hpp" 95 #include "runtime/task.hpp" 96 #include "runtime/thread.inline.hpp" 97 #include "runtime/threadCritical.hpp" 98 #include "runtime/threadSMR.inline.hpp" 99 #include "runtime/threadStatisticalInfo.hpp" 100 #include "runtime/timer.hpp" 101 #include "runtime/timerTrace.hpp" 102 #include "runtime/vframe.inline.hpp" 103 #include "runtime/vframeArray.hpp" 104 #include "runtime/vframe_hp.hpp" 105 #include "runtime/vmThread.hpp" 106 #include "runtime/vmOperations.hpp" 107 #include "runtime/vm_version.hpp" 108 #include "services/attachListener.hpp" 109 #include "services/management.hpp" 110 #include "services/memTracker.hpp" 111 #include "services/threadService.hpp" 112 #include "utilities/align.hpp" 113 #include "utilities/copy.hpp" 114 #include "utilities/defaultStream.hpp" 115 #include "utilities/dtrace.hpp" 116 #include "utilities/events.hpp" 117 #include "utilities/macros.hpp" 118 #include "utilities/preserveException.hpp" 119 #include "utilities/singleWriterSynchronizer.hpp" 120 #include "utilities/vmError.hpp" 121 #if INCLUDE_JVMCI 122 #include "jvmci/jvmci.hpp" 123 #include "jvmci/jvmciEnv.hpp" 124 #endif 125 #ifdef COMPILER1 126 #include "c1/c1_Compiler.hpp" 127 #endif 128 #ifdef COMPILER2 129 #include "opto/c2compiler.hpp" 130 #include "opto/idealGraphPrinter.hpp" 131 #endif 132 #if INCLUDE_RTM_OPT 133 #include "runtime/rtmLocking.hpp" 134 #endif 135 #if INCLUDE_JFR 136 #include "jfr/jfr.hpp" 137 #endif 138 139 // Initialization after module runtime initialization 140 void universe_post_module_init(); // must happen after call_initPhase2 141 142 #ifdef DTRACE_ENABLED 143 144 // Only bother with this argument setup if dtrace is available 145 146 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 147 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 148 149 #define DTRACE_THREAD_PROBE(probe, javathread) \ 150 { \ 151 ResourceMark rm(this); \ 152 int len = 0; \ 153 const char* name = (javathread)->get_thread_name(); \ 154 len = strlen(name); \ 155 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 156 (char *) name, len, \ 157 java_lang_Thread::thread_id((javathread)->threadObj()), \ 158 (uintptr_t) (javathread)->osthread()->thread_id(), \ 159 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 160 } 161 162 #else // ndef DTRACE_ENABLED 163 164 #define DTRACE_THREAD_PROBE(probe, javathread) 165 166 #endif // ndef DTRACE_ENABLED 167 168 #ifndef USE_LIBRARY_BASED_TLS_ONLY 169 // Current thread is maintained as a thread-local variable 170 THREAD_LOCAL Thread* Thread::_thr_current = NULL; 171 #endif 172 173 // ======= Thread ======== 174 // Support for forcing alignment of thread objects for biased locking 175 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 176 if (UseBiasedLocking) { 177 const size_t alignment = markWord::biased_lock_alignment; 178 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 179 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 180 : AllocateHeap(aligned_size, flags, CURRENT_PC, 181 AllocFailStrategy::RETURN_NULL); 182 void* aligned_addr = align_up(real_malloc_addr, alignment); 183 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 184 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 185 "JavaThread alignment code overflowed allocated storage"); 186 if (aligned_addr != real_malloc_addr) { 187 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 188 p2i(real_malloc_addr), 189 p2i(aligned_addr)); 190 } 191 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 192 return aligned_addr; 193 } else { 194 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 195 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 196 } 197 } 198 199 void Thread::operator delete(void* p) { 200 if (UseBiasedLocking) { 201 FreeHeap(((Thread*) p)->_real_malloc_address); 202 } else { 203 FreeHeap(p); 204 } 205 } 206 207 void JavaThread::smr_delete() { 208 if (_on_thread_list) { 209 ThreadsSMRSupport::smr_delete(this); 210 } else { 211 delete this; 212 } 213 } 214 215 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 216 // JavaThread 217 218 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;) 219 220 Thread::Thread() { 221 222 DEBUG_ONLY(_run_state = PRE_CALL_RUN;) 223 224 // stack and get_thread 225 set_stack_base(NULL); 226 set_stack_size(0); 227 set_lgrp_id(-1); 228 DEBUG_ONLY(clear_suspendible_thread();) 229 230 // allocated data structures 231 set_osthread(NULL); 232 set_resource_area(new (mtThread)ResourceArea()); 233 DEBUG_ONLY(_current_resource_mark = NULL;) 234 set_handle_area(new (mtThread) HandleArea(NULL)); 235 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 236 set_active_handles(NULL); 237 set_free_handle_block(NULL); 238 set_last_handle_mark(NULL); 239 DEBUG_ONLY(_missed_ic_stub_refill_verifier = NULL); 240 241 // Initial value of zero ==> never claimed. 242 _threads_do_token = 0; 243 _threads_hazard_ptr = NULL; 244 _threads_list_ptr = NULL; 245 _nested_threads_hazard_ptr_cnt = 0; 246 _rcu_counter = 0; 247 248 // the handle mark links itself to last_handle_mark 249 new HandleMark(this); 250 251 // plain initialization 252 debug_only(_owned_locks = NULL;) 253 NOT_PRODUCT(_no_safepoint_count = 0;) 254 NOT_PRODUCT(_skip_gcalot = false;) 255 _jvmti_env_iteration_count = 0; 256 set_allocated_bytes(0); 257 _vm_operation_started_count = 0; 258 _vm_operation_completed_count = 0; 259 _current_pending_monitor = NULL; 260 _current_pending_monitor_is_from_java = true; 261 _current_waiting_monitor = NULL; 262 _current_pending_raw_monitor = NULL; 263 _num_nested_signal = 0; 264 om_free_list = NULL; 265 om_free_count = 0; 266 om_free_provision = 32; 267 om_in_use_list = NULL; 268 om_in_use_count = 0; 269 270 #ifdef ASSERT 271 _visited_for_critical_count = false; 272 #endif 273 274 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, 275 Monitor::_safepoint_check_sometimes); 276 _suspend_flags = 0; 277 278 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 279 _hashStateX = os::random(); 280 _hashStateY = 842502087; 281 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 282 _hashStateW = 273326509; 283 284 _OnTrap = 0; 285 _Stalled = 0; 286 _TypeTag = 0x2BAD; 287 288 // Many of the following fields are effectively final - immutable 289 // Note that nascent threads can't use the Native Monitor-Mutex 290 // construct until the _MutexEvent is initialized ... 291 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 292 // we might instead use a stack of ParkEvents that we could provision on-demand. 293 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 294 // and ::Release() 295 _ParkEvent = ParkEvent::Allocate(this); 296 _MuxEvent = ParkEvent::Allocate(this); 297 298 #ifdef CHECK_UNHANDLED_OOPS 299 if (CheckUnhandledOops) { 300 _unhandled_oops = new UnhandledOops(this); 301 } 302 #endif // CHECK_UNHANDLED_OOPS 303 #ifdef ASSERT 304 if (UseBiasedLocking) { 305 assert(is_aligned(this, markWord::biased_lock_alignment), "forced alignment of thread object failed"); 306 assert(this == _real_malloc_address || 307 this == align_up(_real_malloc_address, markWord::biased_lock_alignment), 308 "bug in forced alignment of thread objects"); 309 } 310 #endif // ASSERT 311 312 // Notify the barrier set that a thread is being created. The initial 313 // thread is created before the barrier set is available. The call to 314 // BarrierSet::on_thread_create() for this thread is therefore deferred 315 // to BarrierSet::set_barrier_set(). 316 BarrierSet* const barrier_set = BarrierSet::barrier_set(); 317 if (barrier_set != NULL) { 318 barrier_set->on_thread_create(this); 319 } else { 320 // Only the main thread should be created before the barrier set 321 // and that happens just before Thread::current is set. No other thread 322 // can attach as the VM is not created yet, so they can't execute this code. 323 // If the main thread creates other threads before the barrier set that is an error. 324 assert(Thread::current_or_null() == NULL, "creating thread before barrier set"); 325 } 326 } 327 328 void Thread::initialize_thread_current() { 329 #ifndef USE_LIBRARY_BASED_TLS_ONLY 330 assert(_thr_current == NULL, "Thread::current already initialized"); 331 _thr_current = this; 332 #endif 333 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized"); 334 ThreadLocalStorage::set_thread(this); 335 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 336 } 337 338 void Thread::clear_thread_current() { 339 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 340 #ifndef USE_LIBRARY_BASED_TLS_ONLY 341 _thr_current = NULL; 342 #endif 343 ThreadLocalStorage::set_thread(NULL); 344 } 345 346 void Thread::record_stack_base_and_size() { 347 // Note: at this point, Thread object is not yet initialized. Do not rely on 348 // any members being initialized. Do not rely on Thread::current() being set. 349 // If possible, refrain from doing anything which may crash or assert since 350 // quite probably those crash dumps will be useless. 351 set_stack_base(os::current_stack_base()); 352 set_stack_size(os::current_stack_size()); 353 354 #ifdef SOLARIS 355 if (os::is_primordial_thread()) { 356 os::Solaris::correct_stack_boundaries_for_primordial_thread(this); 357 } 358 #endif 359 360 // Set stack limits after thread is initialized. 361 if (is_Java_thread()) { 362 ((JavaThread*) this)->set_stack_overflow_limit(); 363 ((JavaThread*) this)->set_reserved_stack_activation(stack_base()); 364 } 365 } 366 367 #if INCLUDE_NMT 368 void Thread::register_thread_stack_with_NMT() { 369 MemTracker::record_thread_stack(stack_end(), stack_size()); 370 } 371 #endif // INCLUDE_NMT 372 373 void Thread::call_run() { 374 DEBUG_ONLY(_run_state = CALL_RUN;) 375 376 // At this point, Thread object should be fully initialized and 377 // Thread::current() should be set. 378 379 assert(Thread::current_or_null() != NULL, "current thread is unset"); 380 assert(Thread::current_or_null() == this, "current thread is wrong"); 381 382 // Perform common initialization actions 383 384 register_thread_stack_with_NMT(); 385 386 JFR_ONLY(Jfr::on_thread_start(this);) 387 388 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: " 389 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).", 390 os::current_thread_id(), p2i(stack_base() - stack_size()), 391 p2i(stack_base()), stack_size()/1024); 392 393 // Perform <ChildClass> initialization actions 394 DEBUG_ONLY(_run_state = PRE_RUN;) 395 this->pre_run(); 396 397 // Invoke <ChildClass>::run() 398 DEBUG_ONLY(_run_state = RUN;) 399 this->run(); 400 // Returned from <ChildClass>::run(). Thread finished. 401 402 // Perform common tear-down actions 403 404 assert(Thread::current_or_null() != NULL, "current thread is unset"); 405 assert(Thread::current_or_null() == this, "current thread is wrong"); 406 407 // Perform <ChildClass> tear-down actions 408 DEBUG_ONLY(_run_state = POST_RUN;) 409 this->post_run(); 410 411 // Note: at this point the thread object may already have deleted itself, 412 // so from here on do not dereference *this*. Not all thread types currently 413 // delete themselves when they terminate. But no thread should ever be deleted 414 // asynchronously with respect to its termination - that is what _run_state can 415 // be used to check. 416 417 assert(Thread::current_or_null() == NULL, "current thread still present"); 418 } 419 420 Thread::~Thread() { 421 422 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually 423 // get started due to errors etc. Any active thread should at least reach post_run 424 // before it is deleted (usually in post_run()). 425 assert(_run_state == PRE_CALL_RUN || 426 _run_state == POST_RUN, "Active Thread deleted before post_run(): " 427 "_run_state=%d", (int)_run_state); 428 429 // Notify the barrier set that a thread is being destroyed. Note that a barrier 430 // set might not be available if we encountered errors during bootstrapping. 431 BarrierSet* const barrier_set = BarrierSet::barrier_set(); 432 if (barrier_set != NULL) { 433 barrier_set->on_thread_destroy(this); 434 } 435 436 // stack_base can be NULL if the thread is never started or exited before 437 // record_stack_base_and_size called. Although, we would like to ensure 438 // that all started threads do call record_stack_base_and_size(), there is 439 // not proper way to enforce that. 440 #if INCLUDE_NMT 441 if (_stack_base != NULL) { 442 MemTracker::release_thread_stack(stack_end(), stack_size()); 443 #ifdef ASSERT 444 set_stack_base(NULL); 445 #endif 446 } 447 #endif // INCLUDE_NMT 448 449 // deallocate data structures 450 delete resource_area(); 451 // since the handle marks are using the handle area, we have to deallocated the root 452 // handle mark before deallocating the thread's handle area, 453 assert(last_handle_mark() != NULL, "check we have an element"); 454 delete last_handle_mark(); 455 assert(last_handle_mark() == NULL, "check we have reached the end"); 456 457 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 458 // We NULL out the fields for good hygiene. 459 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 460 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 461 462 delete handle_area(); 463 delete metadata_handles(); 464 465 // SR_handler uses this as a termination indicator - 466 // needs to happen before os::free_thread() 467 delete _SR_lock; 468 _SR_lock = NULL; 469 470 // osthread() can be NULL, if creation of thread failed. 471 if (osthread() != NULL) os::free_thread(osthread()); 472 473 // Clear Thread::current if thread is deleting itself and it has not 474 // already been done. This must be done before the memory is deallocated. 475 // Needed to ensure JNI correctly detects non-attached threads. 476 if (this == Thread::current_or_null()) { 477 Thread::clear_thread_current(); 478 } 479 480 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 481 } 482 483 #ifdef ASSERT 484 // A JavaThread is considered "dangling" if it is not the current 485 // thread, has been added the Threads list, the system is not at a 486 // safepoint and the Thread is not "protected". 487 // 488 void Thread::check_for_dangling_thread_pointer(Thread *thread) { 489 assert(!thread->is_Java_thread() || Thread::current() == thread || 490 !((JavaThread *) thread)->on_thread_list() || 491 SafepointSynchronize::is_at_safepoint() || 492 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread), 493 "possibility of dangling Thread pointer"); 494 } 495 #endif 496 497 ThreadPriority Thread::get_priority(const Thread* const thread) { 498 ThreadPriority priority; 499 // Can return an error! 500 (void)os::get_priority(thread, priority); 501 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 502 return priority; 503 } 504 505 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 506 debug_only(check_for_dangling_thread_pointer(thread);) 507 // Can return an error! 508 (void)os::set_priority(thread, priority); 509 } 510 511 512 void Thread::start(Thread* thread) { 513 // Start is different from resume in that its safety is guaranteed by context or 514 // being called from a Java method synchronized on the Thread object. 515 if (!DisableStartThread) { 516 if (thread->is_Java_thread()) { 517 // Initialize the thread state to RUNNABLE before starting this thread. 518 // Can not set it after the thread started because we do not know the 519 // exact thread state at that time. It could be in MONITOR_WAIT or 520 // in SLEEPING or some other state. 521 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 522 java_lang_Thread::RUNNABLE); 523 } 524 os::start_thread(thread); 525 } 526 } 527 528 class InstallAsyncExceptionClosure : public HandshakeClosure { 529 Handle _throwable; // The Throwable thrown at the target Thread 530 public: 531 InstallAsyncExceptionClosure(Handle throwable) : HandshakeClosure("InstallAsyncException"), _throwable(throwable) {} 532 533 void do_thread(Thread* thr) { 534 JavaThread* target = (JavaThread*)thr; 535 // Note that this now allows multiple ThreadDeath exceptions to be 536 // thrown at a thread. 537 // The target thread has run and has not exited yet. 538 target->send_thread_stop(_throwable()); 539 } 540 }; 541 542 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 543 Handle throwable(Thread::current(), java_throwable); 544 JavaThread* target = java_lang_Thread::thread(java_thread); 545 InstallAsyncExceptionClosure vm_stop(throwable); 546 Handshake::execute(&vm_stop, target); 547 } 548 549 550 // Check if an external suspend request has completed (or has been 551 // cancelled). Returns true if the thread is externally suspended and 552 // false otherwise. 553 // 554 // The bits parameter returns information about the code path through 555 // the routine. Useful for debugging: 556 // 557 // set in is_ext_suspend_completed(): 558 // 0x00000001 - routine was entered 559 // 0x00000010 - routine return false at end 560 // 0x00000100 - thread exited (return false) 561 // 0x00000200 - suspend request cancelled (return false) 562 // 0x00000400 - thread suspended (return true) 563 // 0x00001000 - thread is in a suspend equivalent state (return true) 564 // 0x00002000 - thread is native and walkable (return true) 565 // 0x00004000 - thread is native_trans and walkable (needed retry) 566 // 567 // set in wait_for_ext_suspend_completion(): 568 // 0x00010000 - routine was entered 569 // 0x00020000 - suspend request cancelled before loop (return false) 570 // 0x00040000 - thread suspended before loop (return true) 571 // 0x00080000 - suspend request cancelled in loop (return false) 572 // 0x00100000 - thread suspended in loop (return true) 573 // 0x00200000 - suspend not completed during retry loop (return false) 574 575 // Helper class for tracing suspend wait debug bits. 576 // 577 // 0x00000100 indicates that the target thread exited before it could 578 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 579 // 0x00080000 each indicate a cancelled suspend request so they don't 580 // count as wait failures either. 581 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 582 583 class TraceSuspendDebugBits : public StackObj { 584 private: 585 JavaThread * jt; 586 bool is_wait; 587 bool called_by_wait; // meaningful when !is_wait 588 uint32_t * bits; 589 590 public: 591 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 592 uint32_t *_bits) { 593 jt = _jt; 594 is_wait = _is_wait; 595 called_by_wait = _called_by_wait; 596 bits = _bits; 597 } 598 599 ~TraceSuspendDebugBits() { 600 if (!is_wait) { 601 #if 1 602 // By default, don't trace bits for is_ext_suspend_completed() calls. 603 // That trace is very chatty. 604 return; 605 #else 606 if (!called_by_wait) { 607 // If tracing for is_ext_suspend_completed() is enabled, then only 608 // trace calls to it from wait_for_ext_suspend_completion() 609 return; 610 } 611 #endif 612 } 613 614 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 615 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 616 MutexLocker ml(Threads_lock); // needed for get_thread_name() 617 ResourceMark rm; 618 619 tty->print_cr( 620 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 621 jt->get_thread_name(), *bits); 622 623 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 624 } 625 } 626 } 627 }; 628 #undef DEBUG_FALSE_BITS 629 630 631 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 632 uint32_t *bits) { 633 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 634 635 bool did_trans_retry = false; // only do thread_in_native_trans retry once 636 bool do_trans_retry; // flag to force the retry 637 638 *bits |= 0x00000001; 639 640 do { 641 do_trans_retry = false; 642 643 if (is_exiting()) { 644 // Thread is in the process of exiting. This is always checked 645 // first to reduce the risk of dereferencing a freed JavaThread. 646 *bits |= 0x00000100; 647 return false; 648 } 649 650 if (!is_external_suspend()) { 651 // Suspend request is cancelled. This is always checked before 652 // is_ext_suspended() to reduce the risk of a rogue resume 653 // confusing the thread that made the suspend request. 654 *bits |= 0x00000200; 655 return false; 656 } 657 658 if (is_ext_suspended()) { 659 // thread is suspended 660 *bits |= 0x00000400; 661 return true; 662 } 663 664 // Now that we no longer do hard suspends of threads running 665 // native code, the target thread can be changing thread state 666 // while we are in this routine: 667 // 668 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 669 // 670 // We save a copy of the thread state as observed at this moment 671 // and make our decision about suspend completeness based on the 672 // copy. This closes the race where the thread state is seen as 673 // _thread_in_native_trans in the if-thread_blocked check, but is 674 // seen as _thread_blocked in if-thread_in_native_trans check. 675 JavaThreadState save_state = thread_state(); 676 677 if (save_state == _thread_blocked && is_suspend_equivalent()) { 678 // If the thread's state is _thread_blocked and this blocking 679 // condition is known to be equivalent to a suspend, then we can 680 // consider the thread to be externally suspended. This means that 681 // the code that sets _thread_blocked has been modified to do 682 // self-suspension if the blocking condition releases. We also 683 // used to check for CONDVAR_WAIT here, but that is now covered by 684 // the _thread_blocked with self-suspension check. 685 // 686 // Return true since we wouldn't be here unless there was still an 687 // external suspend request. 688 *bits |= 0x00001000; 689 return true; 690 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 691 // Threads running native code will self-suspend on native==>VM/Java 692 // transitions. If its stack is walkable (should always be the case 693 // unless this function is called before the actual java_suspend() 694 // call), then the wait is done. 695 *bits |= 0x00002000; 696 return true; 697 } else if (!called_by_wait && !did_trans_retry && 698 save_state == _thread_in_native_trans && 699 frame_anchor()->walkable()) { 700 // The thread is transitioning from thread_in_native to another 701 // thread state. check_safepoint_and_suspend_for_native_trans() 702 // will force the thread to self-suspend. If it hasn't gotten 703 // there yet we may have caught the thread in-between the native 704 // code check above and the self-suspend. Lucky us. If we were 705 // called by wait_for_ext_suspend_completion(), then it 706 // will be doing the retries so we don't have to. 707 // 708 // Since we use the saved thread state in the if-statement above, 709 // there is a chance that the thread has already transitioned to 710 // _thread_blocked by the time we get here. In that case, we will 711 // make a single unnecessary pass through the logic below. This 712 // doesn't hurt anything since we still do the trans retry. 713 714 *bits |= 0x00004000; 715 716 // Once the thread leaves thread_in_native_trans for another 717 // thread state, we break out of this retry loop. We shouldn't 718 // need this flag to prevent us from getting back here, but 719 // sometimes paranoia is good. 720 did_trans_retry = true; 721 722 // We wait for the thread to transition to a more usable state. 723 for (int i = 1; i <= SuspendRetryCount; i++) { 724 // We used to do an "os::yield_all(i)" call here with the intention 725 // that yielding would increase on each retry. However, the parameter 726 // is ignored on Linux which means the yield didn't scale up. Waiting 727 // on the SR_lock below provides a much more predictable scale up for 728 // the delay. It also provides a simple/direct point to check for any 729 // safepoint requests from the VMThread 730 731 // temporarily drops SR_lock while doing wait with safepoint check 732 // (if we're a JavaThread - the WatcherThread can also call this) 733 // and increase delay with each retry 734 if (Thread::current()->is_Java_thread()) { 735 SR_lock()->wait(i * delay); 736 } else { 737 SR_lock()->wait_without_safepoint_check(i * delay); 738 } 739 740 // check the actual thread state instead of what we saved above 741 if (thread_state() != _thread_in_native_trans) { 742 // the thread has transitioned to another thread state so 743 // try all the checks (except this one) one more time. 744 do_trans_retry = true; 745 break; 746 } 747 } // end retry loop 748 749 750 } 751 } while (do_trans_retry); 752 753 *bits |= 0x00000010; 754 return false; 755 } 756 757 // Wait for an external suspend request to complete (or be cancelled). 758 // Returns true if the thread is externally suspended and false otherwise. 759 // 760 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 761 uint32_t *bits) { 762 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 763 false /* !called_by_wait */, bits); 764 765 // local flag copies to minimize SR_lock hold time 766 bool is_suspended; 767 bool pending; 768 uint32_t reset_bits; 769 770 // set a marker so is_ext_suspend_completed() knows we are the caller 771 *bits |= 0x00010000; 772 773 // We use reset_bits to reinitialize the bits value at the top of 774 // each retry loop. This allows the caller to make use of any 775 // unused bits for their own marking purposes. 776 reset_bits = *bits; 777 778 { 779 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 780 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 781 delay, bits); 782 pending = is_external_suspend(); 783 } 784 // must release SR_lock to allow suspension to complete 785 786 if (!pending) { 787 // A cancelled suspend request is the only false return from 788 // is_ext_suspend_completed() that keeps us from entering the 789 // retry loop. 790 *bits |= 0x00020000; 791 return false; 792 } 793 794 if (is_suspended) { 795 *bits |= 0x00040000; 796 return true; 797 } 798 799 for (int i = 1; i <= retries; i++) { 800 *bits = reset_bits; // reinit to only track last retry 801 802 // We used to do an "os::yield_all(i)" call here with the intention 803 // that yielding would increase on each retry. However, the parameter 804 // is ignored on Linux which means the yield didn't scale up. Waiting 805 // on the SR_lock below provides a much more predictable scale up for 806 // the delay. It also provides a simple/direct point to check for any 807 // safepoint requests from the VMThread 808 809 { 810 Thread* t = Thread::current(); 811 MonitorLocker ml(SR_lock(), 812 t->is_Java_thread() ? Mutex::_safepoint_check_flag : Mutex::_no_safepoint_check_flag); 813 // wait with safepoint check (if we're a JavaThread - the WatcherThread 814 // can also call this) and increase delay with each retry 815 ml.wait(i * delay); 816 817 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 818 delay, bits); 819 820 // It is possible for the external suspend request to be cancelled 821 // (by a resume) before the actual suspend operation is completed. 822 // Refresh our local copy to see if we still need to wait. 823 pending = is_external_suspend(); 824 } 825 826 if (!pending) { 827 // A cancelled suspend request is the only false return from 828 // is_ext_suspend_completed() that keeps us from staying in the 829 // retry loop. 830 *bits |= 0x00080000; 831 return false; 832 } 833 834 if (is_suspended) { 835 *bits |= 0x00100000; 836 return true; 837 } 838 } // end retry loop 839 840 // thread did not suspend after all our retries 841 *bits |= 0x00200000; 842 return false; 843 } 844 845 // Called from API entry points which perform stack walking. If the 846 // associated JavaThread is the current thread, then wait_for_suspend 847 // is not used. Otherwise, it determines if we should wait for the 848 // "other" thread to complete external suspension. (NOTE: in future 849 // releases the suspension mechanism should be reimplemented so this 850 // is not necessary.) 851 // 852 bool 853 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) { 854 if (this != JavaThread::current()) { 855 // "other" threads require special handling. 856 if (wait_for_suspend) { 857 // We are allowed to wait for the external suspend to complete 858 // so give the other thread a chance to get suspended. 859 if (!wait_for_ext_suspend_completion(SuspendRetryCount, 860 SuspendRetryDelay, bits)) { 861 // Didn't make it so let the caller know. 862 return false; 863 } 864 } 865 // We aren't allowed to wait for the external suspend to complete 866 // so if the other thread isn't externally suspended we need to 867 // let the caller know. 868 else if (!is_ext_suspend_completed_with_lock(bits)) { 869 return false; 870 } 871 } 872 873 return true; 874 } 875 876 // GC Support 877 bool Thread::claim_par_threads_do(uintx claim_token) { 878 uintx token = _threads_do_token; 879 if (token != claim_token) { 880 uintx res = Atomic::cmpxchg(&_threads_do_token, token, claim_token); 881 if (res == token) { 882 return true; 883 } 884 guarantee(res == claim_token, "invariant"); 885 } 886 return false; 887 } 888 889 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 890 active_handles()->oops_do(f); 891 // Do oop for ThreadShadow 892 f->do_oop((oop*)&_pending_exception); 893 handle_area()->oops_do(f); 894 895 // We scan thread local monitor lists here, and the remaining global 896 // monitors in ObjectSynchronizer::oops_do(). 897 ObjectSynchronizer::thread_local_used_oops_do(this, f); 898 } 899 900 void Thread::metadata_handles_do(void f(Metadata*)) { 901 // Only walk the Handles in Thread. 902 if (metadata_handles() != NULL) { 903 for (int i = 0; i< metadata_handles()->length(); i++) { 904 f(metadata_handles()->at(i)); 905 } 906 } 907 } 908 909 void Thread::print_on(outputStream* st, bool print_extended_info) const { 910 // get_priority assumes osthread initialized 911 if (osthread() != NULL) { 912 int os_prio; 913 if (os::get_native_priority(this, &os_prio) == OS_OK) { 914 st->print("os_prio=%d ", os_prio); 915 } 916 917 st->print("cpu=%.2fms ", 918 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0 919 ); 920 st->print("elapsed=%.2fs ", 921 _statistical_info.getElapsedTime() / 1000.0 922 ); 923 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) { 924 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes(); 925 st->print("allocated=" SIZE_FORMAT "%s ", 926 byte_size_in_proper_unit(allocated_bytes), 927 proper_unit_for_byte_size(allocated_bytes) 928 ); 929 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount()); 930 } 931 932 st->print("tid=" INTPTR_FORMAT " ", p2i(this)); 933 osthread()->print_on(st); 934 } 935 ThreadsSMRSupport::print_info_on(this, st); 936 st->print(" "); 937 debug_only(if (WizardMode) print_owned_locks_on(st);) 938 } 939 940 void Thread::print() const { print_on(tty); } 941 942 // Thread::print_on_error() is called by fatal error handler. Don't use 943 // any lock or allocate memory. 944 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 945 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates"); 946 947 if (is_VM_thread()) { st->print("VMThread"); } 948 else if (is_GC_task_thread()) { st->print("GCTaskThread"); } 949 else if (is_Watcher_thread()) { st->print("WatcherThread"); } 950 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); } 951 else { st->print("Thread"); } 952 953 if (is_Named_thread()) { 954 st->print(" \"%s\"", name()); 955 } 956 957 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 958 p2i(stack_end()), p2i(stack_base())); 959 960 if (osthread()) { 961 st->print(" [id=%d]", osthread()->thread_id()); 962 } 963 964 ThreadsSMRSupport::print_info_on(this, st); 965 } 966 967 void Thread::print_value_on(outputStream* st) const { 968 if (is_Named_thread()) { 969 st->print(" \"%s\" ", name()); 970 } 971 st->print(INTPTR_FORMAT, p2i(this)); // print address 972 } 973 974 #ifdef ASSERT 975 void Thread::print_owned_locks_on(outputStream* st) const { 976 Mutex* cur = _owned_locks; 977 if (cur == NULL) { 978 st->print(" (no locks) "); 979 } else { 980 st->print_cr(" Locks owned:"); 981 while (cur) { 982 cur->print_on(st); 983 cur = cur->next(); 984 } 985 } 986 } 987 988 // Checks safepoint allowed and clears unhandled oops at potential safepoints. 989 void Thread::check_possible_safepoint() { 990 if (!is_Java_thread()) return; 991 992 if (_no_safepoint_count > 0) { 993 print_owned_locks(); 994 fatal("Possible safepoint reached by thread that does not allow it"); 995 } 996 #ifdef CHECK_UNHANDLED_OOPS 997 // Clear unhandled oops in JavaThreads so we get a crash right away. 998 clear_unhandled_oops(); 999 #endif // CHECK_UNHANDLED_OOPS 1000 } 1001 1002 void Thread::check_for_valid_safepoint_state() { 1003 if (!is_Java_thread()) return; 1004 1005 // Check NoSafepointVerifier, which is implied by locks taken that can be 1006 // shared with the VM thread. This makes sure that no locks with allow_vm_block 1007 // are held. 1008 check_possible_safepoint(); 1009 1010 if (((JavaThread*)this)->thread_state() != _thread_in_vm) { 1011 fatal("LEAF method calling lock?"); 1012 } 1013 1014 if (GCALotAtAllSafepoints) { 1015 // We could enter a safepoint here and thus have a gc 1016 InterfaceSupport::check_gc_alot(); 1017 } 1018 } 1019 #endif // ASSERT 1020 1021 bool Thread::is_in_stack(address adr) const { 1022 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 1023 address end = os::current_stack_pointer(); 1024 // Allow non Java threads to call this without stack_base 1025 if (_stack_base == NULL) return true; 1026 if (stack_base() > adr && adr >= end) return true; 1027 1028 return false; 1029 } 1030 1031 bool Thread::is_in_usable_stack(address adr) const { 1032 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0; 1033 size_t usable_stack_size = _stack_size - stack_guard_size; 1034 1035 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 1036 } 1037 1038 1039 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 1040 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 1041 // used for compilation in the future. If that change is made, the need for these methods 1042 // should be revisited, and they should be removed if possible. 1043 1044 bool Thread::is_lock_owned(address adr) const { 1045 return on_local_stack(adr); 1046 } 1047 1048 bool Thread::set_as_starting_thread() { 1049 assert(_starting_thread == NULL, "already initialized: " 1050 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread)); 1051 // NOTE: this must be called inside the main thread. 1052 DEBUG_ONLY(_starting_thread = this;) 1053 return os::create_main_thread((JavaThread*)this); 1054 } 1055 1056 static void initialize_class(Symbol* class_name, TRAPS) { 1057 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 1058 InstanceKlass::cast(klass)->initialize(CHECK); 1059 } 1060 1061 1062 // Creates the initial ThreadGroup 1063 static Handle create_initial_thread_group(TRAPS) { 1064 Handle system_instance = JavaCalls::construct_new_instance( 1065 SystemDictionary::ThreadGroup_klass(), 1066 vmSymbols::void_method_signature(), 1067 CHECK_NH); 1068 Universe::set_system_thread_group(system_instance()); 1069 1070 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 1071 Handle main_instance = JavaCalls::construct_new_instance( 1072 SystemDictionary::ThreadGroup_klass(), 1073 vmSymbols::threadgroup_string_void_signature(), 1074 system_instance, 1075 string, 1076 CHECK_NH); 1077 return main_instance; 1078 } 1079 1080 // Creates the initial Thread 1081 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 1082 TRAPS) { 1083 InstanceKlass* ik = SystemDictionary::Thread_klass(); 1084 assert(ik->is_initialized(), "must be"); 1085 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL); 1086 1087 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread 1088 // constructor calls Thread.current(), which must be set here for the 1089 // initial thread. 1090 java_lang_Thread::set_thread(thread_oop(), thread); 1091 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1092 thread->set_threadObj(thread_oop()); 1093 1094 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1095 1096 JavaValue result(T_VOID); 1097 JavaCalls::call_special(&result, thread_oop, 1098 ik, 1099 vmSymbols::object_initializer_name(), 1100 vmSymbols::threadgroup_string_void_signature(), 1101 thread_group, 1102 string, 1103 CHECK_NULL); 1104 return thread_oop(); 1105 } 1106 1107 char java_runtime_name[128] = ""; 1108 char java_runtime_version[128] = ""; 1109 char java_runtime_vendor_version[128] = ""; 1110 char java_runtime_vendor_vm_bug_url[128] = ""; 1111 1112 // extract the JRE name from java.lang.VersionProps.java_runtime_name 1113 static const char* get_java_runtime_name(TRAPS) { 1114 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1115 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1116 fieldDescriptor fd; 1117 bool found = k != NULL && 1118 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1119 vmSymbols::string_signature(), &fd); 1120 if (found) { 1121 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1122 if (name_oop == NULL) { 1123 return NULL; 1124 } 1125 const char* name = java_lang_String::as_utf8_string(name_oop, 1126 java_runtime_name, 1127 sizeof(java_runtime_name)); 1128 return name; 1129 } else { 1130 return NULL; 1131 } 1132 } 1133 1134 // extract the JRE version from java.lang.VersionProps.java_runtime_version 1135 static const char* get_java_runtime_version(TRAPS) { 1136 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1137 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1138 fieldDescriptor fd; 1139 bool found = k != NULL && 1140 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1141 vmSymbols::string_signature(), &fd); 1142 if (found) { 1143 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1144 if (name_oop == NULL) { 1145 return NULL; 1146 } 1147 const char* name = java_lang_String::as_utf8_string(name_oop, 1148 java_runtime_version, 1149 sizeof(java_runtime_version)); 1150 return name; 1151 } else { 1152 return NULL; 1153 } 1154 } 1155 1156 // extract the JRE vendor version from java.lang.VersionProps.VENDOR_VERSION 1157 static const char* get_java_runtime_vendor_version(TRAPS) { 1158 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1159 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1160 fieldDescriptor fd; 1161 bool found = k != NULL && 1162 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_vendor_version_name(), 1163 vmSymbols::string_signature(), &fd); 1164 if (found) { 1165 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1166 if (name_oop == NULL) { 1167 return NULL; 1168 } 1169 const char* name = java_lang_String::as_utf8_string(name_oop, 1170 java_runtime_vendor_version, 1171 sizeof(java_runtime_vendor_version)); 1172 return name; 1173 } else { 1174 return NULL; 1175 } 1176 } 1177 1178 // extract the JRE vendor VM bug URL from java.lang.VersionProps.VENDOR_URL_VM_BUG 1179 static const char* get_java_runtime_vendor_vm_bug_url(TRAPS) { 1180 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1181 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1182 fieldDescriptor fd; 1183 bool found = k != NULL && 1184 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_vendor_vm_bug_url_name(), 1185 vmSymbols::string_signature(), &fd); 1186 if (found) { 1187 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1188 if (name_oop == NULL) { 1189 return NULL; 1190 } 1191 const char* name = java_lang_String::as_utf8_string(name_oop, 1192 java_runtime_vendor_vm_bug_url, 1193 sizeof(java_runtime_vendor_vm_bug_url)); 1194 return name; 1195 } else { 1196 return NULL; 1197 } 1198 } 1199 1200 // General purpose hook into Java code, run once when the VM is initialized. 1201 // The Java library method itself may be changed independently from the VM. 1202 static void call_postVMInitHook(TRAPS) { 1203 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD); 1204 if (klass != NULL) { 1205 JavaValue result(T_VOID); 1206 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1207 vmSymbols::void_method_signature(), 1208 CHECK); 1209 } 1210 } 1211 1212 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 1213 bool daemon, TRAPS) { 1214 assert(thread_group.not_null(), "thread group should be specified"); 1215 assert(threadObj() == NULL, "should only create Java thread object once"); 1216 1217 InstanceKlass* ik = SystemDictionary::Thread_klass(); 1218 assert(ik->is_initialized(), "must be"); 1219 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK); 1220 1221 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon. 1222 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread 1223 // constructor calls Thread.current(), which must be set here. 1224 java_lang_Thread::set_thread(thread_oop(), this); 1225 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1226 set_threadObj(thread_oop()); 1227 1228 JavaValue result(T_VOID); 1229 if (thread_name != NULL) { 1230 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1231 // Thread gets assigned specified name and null target 1232 JavaCalls::call_special(&result, 1233 thread_oop, 1234 ik, 1235 vmSymbols::object_initializer_name(), 1236 vmSymbols::threadgroup_string_void_signature(), 1237 thread_group, 1238 name, 1239 THREAD); 1240 } else { 1241 // Thread gets assigned name "Thread-nnn" and null target 1242 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1243 JavaCalls::call_special(&result, 1244 thread_oop, 1245 ik, 1246 vmSymbols::object_initializer_name(), 1247 vmSymbols::threadgroup_runnable_void_signature(), 1248 thread_group, 1249 Handle(), 1250 THREAD); 1251 } 1252 1253 1254 if (daemon) { 1255 java_lang_Thread::set_daemon(thread_oop()); 1256 } 1257 1258 if (HAS_PENDING_EXCEPTION) { 1259 return; 1260 } 1261 1262 Klass* group = SystemDictionary::ThreadGroup_klass(); 1263 Handle threadObj(THREAD, this->threadObj()); 1264 1265 JavaCalls::call_special(&result, 1266 thread_group, 1267 group, 1268 vmSymbols::add_method_name(), 1269 vmSymbols::thread_void_signature(), 1270 threadObj, // Arg 1 1271 THREAD); 1272 } 1273 1274 // List of all NonJavaThreads and safe iteration over that list. 1275 1276 class NonJavaThread::List { 1277 public: 1278 NonJavaThread* volatile _head; 1279 SingleWriterSynchronizer _protect; 1280 1281 List() : _head(NULL), _protect() {} 1282 }; 1283 1284 NonJavaThread::List NonJavaThread::_the_list; 1285 1286 NonJavaThread::Iterator::Iterator() : 1287 _protect_enter(_the_list._protect.enter()), 1288 _current(Atomic::load_acquire(&_the_list._head)) 1289 {} 1290 1291 NonJavaThread::Iterator::~Iterator() { 1292 _the_list._protect.exit(_protect_enter); 1293 } 1294 1295 void NonJavaThread::Iterator::step() { 1296 assert(!end(), "precondition"); 1297 _current = Atomic::load_acquire(&_current->_next); 1298 } 1299 1300 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) { 1301 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!"); 1302 } 1303 1304 NonJavaThread::~NonJavaThread() { } 1305 1306 void NonJavaThread::add_to_the_list() { 1307 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag); 1308 // Initialize BarrierSet-related data before adding to list. 1309 BarrierSet::barrier_set()->on_thread_attach(this); 1310 Atomic::release_store(&_next, _the_list._head); 1311 Atomic::release_store(&_the_list._head, this); 1312 } 1313 1314 void NonJavaThread::remove_from_the_list() { 1315 { 1316 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag); 1317 // Cleanup BarrierSet-related data before removing from list. 1318 BarrierSet::barrier_set()->on_thread_detach(this); 1319 NonJavaThread* volatile* p = &_the_list._head; 1320 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) { 1321 if (t == this) { 1322 *p = _next; 1323 break; 1324 } 1325 } 1326 } 1327 // Wait for any in-progress iterators. Concurrent synchronize is not 1328 // allowed, so do it while holding a dedicated lock. Outside and distinct 1329 // from NJTList_lock in case an iteration attempts to lock it. 1330 MutexLocker ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag); 1331 _the_list._protect.synchronize(); 1332 _next = NULL; // Safe to drop the link now. 1333 } 1334 1335 void NonJavaThread::pre_run() { 1336 add_to_the_list(); 1337 1338 // This is slightly odd in that NamedThread is a subclass, but 1339 // in fact name() is defined in Thread 1340 assert(this->name() != NULL, "thread name was not set before it was started"); 1341 this->set_native_thread_name(this->name()); 1342 } 1343 1344 void NonJavaThread::post_run() { 1345 JFR_ONLY(Jfr::on_thread_exit(this);) 1346 remove_from_the_list(); 1347 // Ensure thread-local-storage is cleared before termination. 1348 Thread::clear_thread_current(); 1349 } 1350 1351 // NamedThread -- non-JavaThread subclasses with multiple 1352 // uniquely named instances should derive from this. 1353 NamedThread::NamedThread() : 1354 NonJavaThread(), 1355 _name(NULL), 1356 _processed_thread(NULL), 1357 _gc_id(GCId::undefined()) 1358 {} 1359 1360 NamedThread::~NamedThread() { 1361 FREE_C_HEAP_ARRAY(char, _name); 1362 } 1363 1364 void NamedThread::set_name(const char* format, ...) { 1365 guarantee(_name == NULL, "Only get to set name once."); 1366 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1367 va_list ap; 1368 va_start(ap, format); 1369 jio_vsnprintf(_name, max_name_len, format, ap); 1370 va_end(ap); 1371 } 1372 1373 void NamedThread::print_on(outputStream* st) const { 1374 st->print("\"%s\" ", name()); 1375 Thread::print_on(st); 1376 st->cr(); 1377 } 1378 1379 1380 // ======= WatcherThread ======== 1381 1382 // The watcher thread exists to simulate timer interrupts. It should 1383 // be replaced by an abstraction over whatever native support for 1384 // timer interrupts exists on the platform. 1385 1386 WatcherThread* WatcherThread::_watcher_thread = NULL; 1387 bool WatcherThread::_startable = false; 1388 volatile bool WatcherThread::_should_terminate = false; 1389 1390 WatcherThread::WatcherThread() : NonJavaThread() { 1391 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1392 if (os::create_thread(this, os::watcher_thread)) { 1393 _watcher_thread = this; 1394 1395 // Set the watcher thread to the highest OS priority which should not be 1396 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1397 // is created. The only normal thread using this priority is the reference 1398 // handler thread, which runs for very short intervals only. 1399 // If the VMThread's priority is not lower than the WatcherThread profiling 1400 // will be inaccurate. 1401 os::set_priority(this, MaxPriority); 1402 if (!DisableStartThread) { 1403 os::start_thread(this); 1404 } 1405 } 1406 } 1407 1408 int WatcherThread::sleep() const { 1409 // The WatcherThread does not participate in the safepoint protocol 1410 // for the PeriodicTask_lock because it is not a JavaThread. 1411 MonitorLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1412 1413 if (_should_terminate) { 1414 // check for termination before we do any housekeeping or wait 1415 return 0; // we did not sleep. 1416 } 1417 1418 // remaining will be zero if there are no tasks, 1419 // causing the WatcherThread to sleep until a task is 1420 // enrolled 1421 int remaining = PeriodicTask::time_to_wait(); 1422 int time_slept = 0; 1423 1424 // we expect this to timeout - we only ever get unparked when 1425 // we should terminate or when a new task has been enrolled 1426 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1427 1428 jlong time_before_loop = os::javaTimeNanos(); 1429 1430 while (true) { 1431 bool timedout = ml.wait(remaining); 1432 jlong now = os::javaTimeNanos(); 1433 1434 if (remaining == 0) { 1435 // if we didn't have any tasks we could have waited for a long time 1436 // consider the time_slept zero and reset time_before_loop 1437 time_slept = 0; 1438 time_before_loop = now; 1439 } else { 1440 // need to recalculate since we might have new tasks in _tasks 1441 time_slept = (int) ((now - time_before_loop) / 1000000); 1442 } 1443 1444 // Change to task list or spurious wakeup of some kind 1445 if (timedout || _should_terminate) { 1446 break; 1447 } 1448 1449 remaining = PeriodicTask::time_to_wait(); 1450 if (remaining == 0) { 1451 // Last task was just disenrolled so loop around and wait until 1452 // another task gets enrolled 1453 continue; 1454 } 1455 1456 remaining -= time_slept; 1457 if (remaining <= 0) { 1458 break; 1459 } 1460 } 1461 1462 return time_slept; 1463 } 1464 1465 void WatcherThread::run() { 1466 assert(this == watcher_thread(), "just checking"); 1467 1468 this->set_active_handles(JNIHandleBlock::allocate_block()); 1469 while (true) { 1470 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1471 assert(watcher_thread() == this, "thread consistency check"); 1472 1473 // Calculate how long it'll be until the next PeriodicTask work 1474 // should be done, and sleep that amount of time. 1475 int time_waited = sleep(); 1476 1477 if (VMError::is_error_reported()) { 1478 // A fatal error has happened, the error handler(VMError::report_and_die) 1479 // should abort JVM after creating an error log file. However in some 1480 // rare cases, the error handler itself might deadlock. Here periodically 1481 // check for error reporting timeouts, and if it happens, just proceed to 1482 // abort the VM. 1483 1484 // This code is in WatcherThread because WatcherThread wakes up 1485 // periodically so the fatal error handler doesn't need to do anything; 1486 // also because the WatcherThread is less likely to crash than other 1487 // threads. 1488 1489 for (;;) { 1490 // Note: we use naked sleep in this loop because we want to avoid using 1491 // any kind of VM infrastructure which may be broken at this point. 1492 if (VMError::check_timeout()) { 1493 // We hit error reporting timeout. Error reporting was interrupted and 1494 // will be wrapping things up now (closing files etc). Give it some more 1495 // time, then quit the VM. 1496 os::naked_short_sleep(200); 1497 // Print a message to stderr. 1498 fdStream err(defaultStream::output_fd()); 1499 err.print_raw_cr("# [ timer expired, abort... ]"); 1500 // skip atexit/vm_exit/vm_abort hooks 1501 os::die(); 1502 } 1503 1504 // Wait a second, then recheck for timeout. 1505 os::naked_short_sleep(999); 1506 } 1507 } 1508 1509 if (_should_terminate) { 1510 // check for termination before posting the next tick 1511 break; 1512 } 1513 1514 PeriodicTask::real_time_tick(time_waited); 1515 } 1516 1517 // Signal that it is terminated 1518 { 1519 MutexLocker mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1520 _watcher_thread = NULL; 1521 Terminator_lock->notify_all(); 1522 } 1523 } 1524 1525 void WatcherThread::start() { 1526 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1527 1528 if (watcher_thread() == NULL && _startable) { 1529 _should_terminate = false; 1530 // Create the single instance of WatcherThread 1531 new WatcherThread(); 1532 } 1533 } 1534 1535 void WatcherThread::make_startable() { 1536 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1537 _startable = true; 1538 } 1539 1540 void WatcherThread::stop() { 1541 { 1542 // Follow normal safepoint aware lock enter protocol since the 1543 // WatcherThread is stopped by another JavaThread. 1544 MutexLocker ml(PeriodicTask_lock); 1545 _should_terminate = true; 1546 1547 WatcherThread* watcher = watcher_thread(); 1548 if (watcher != NULL) { 1549 // unpark the WatcherThread so it can see that it should terminate 1550 watcher->unpark(); 1551 } 1552 } 1553 1554 MonitorLocker mu(Terminator_lock); 1555 1556 while (watcher_thread() != NULL) { 1557 // This wait should make safepoint checks, wait without a timeout, 1558 // and wait as a suspend-equivalent condition. 1559 mu.wait(0, Mutex::_as_suspend_equivalent_flag); 1560 } 1561 } 1562 1563 void WatcherThread::unpark() { 1564 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1565 PeriodicTask_lock->notify(); 1566 } 1567 1568 void WatcherThread::print_on(outputStream* st) const { 1569 st->print("\"%s\" ", name()); 1570 Thread::print_on(st); 1571 st->cr(); 1572 } 1573 1574 // ======= JavaThread ======== 1575 1576 #if INCLUDE_JVMCI 1577 1578 jlong* JavaThread::_jvmci_old_thread_counters; 1579 1580 bool jvmci_counters_include(JavaThread* thread) { 1581 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); 1582 } 1583 1584 void JavaThread::collect_counters(jlong* array, int length) { 1585 assert(length == JVMCICounterSize, "wrong value"); 1586 for (int i = 0; i < length; i++) { 1587 array[i] = _jvmci_old_thread_counters[i]; 1588 } 1589 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) { 1590 if (jvmci_counters_include(tp)) { 1591 for (int i = 0; i < length; i++) { 1592 array[i] += tp->_jvmci_counters[i]; 1593 } 1594 } 1595 } 1596 } 1597 1598 // Attempt to enlarge the array for per thread counters. 1599 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) { 1600 jlong* new_counters = NEW_C_HEAP_ARRAY(jlong, new_size, mtJVMCI); 1601 if (old_counters == NULL) { 1602 old_counters = new_counters; 1603 memset(old_counters, 0, sizeof(jlong) * new_size); 1604 } else { 1605 for (int i = 0; i < MIN2((int) current_size, new_size); i++) { 1606 new_counters[i] = old_counters[i]; 1607 } 1608 if (new_size > current_size) { 1609 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size)); 1610 } 1611 FREE_C_HEAP_ARRAY(jlong, old_counters); 1612 } 1613 return new_counters; 1614 } 1615 1616 // Attempt to enlarge the array for per thread counters. 1617 void JavaThread::resize_counters(int current_size, int new_size) { 1618 _jvmci_counters = resize_counters_array(_jvmci_counters, current_size, new_size); 1619 } 1620 1621 class VM_JVMCIResizeCounters : public VM_Operation { 1622 private: 1623 int _new_size; 1624 1625 public: 1626 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size) { } 1627 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; } 1628 bool allow_nested_vm_operations() const { return true; } 1629 void doit() { 1630 // Resize the old thread counters array 1631 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size); 1632 JavaThread::_jvmci_old_thread_counters = new_counters; 1633 1634 // Now resize each threads array 1635 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) { 1636 tp->resize_counters(JVMCICounterSize, _new_size); 1637 } 1638 JVMCICounterSize = _new_size; 1639 } 1640 }; 1641 1642 void JavaThread::resize_all_jvmci_counters(int new_size) { 1643 VM_JVMCIResizeCounters op(new_size); 1644 VMThread::execute(&op); 1645 } 1646 1647 #endif // INCLUDE_JVMCI 1648 1649 // A JavaThread is a normal Java thread 1650 1651 void JavaThread::initialize() { 1652 // Initialize fields 1653 1654 set_saved_exception_pc(NULL); 1655 set_threadObj(NULL); 1656 _anchor.clear(); 1657 set_entry_point(NULL); 1658 set_jni_functions(jni_functions()); 1659 set_callee_target(NULL); 1660 set_vm_result(NULL); 1661 set_vm_result_2(NULL); 1662 set_vframe_array_head(NULL); 1663 set_vframe_array_last(NULL); 1664 set_deferred_locals(NULL); 1665 set_deopt_mark(NULL); 1666 set_deopt_compiled_method(NULL); 1667 set_monitor_chunks(NULL); 1668 _on_thread_list = false; 1669 _thread_state = _thread_new; 1670 _terminated = _not_terminated; 1671 _array_for_gc = NULL; 1672 _suspend_equivalent = false; 1673 _in_deopt_handler = 0; 1674 _doing_unsafe_access = false; 1675 _stack_guard_state = stack_guard_unused; 1676 #if INCLUDE_JVMCI 1677 _pending_monitorenter = false; 1678 _pending_deoptimization = -1; 1679 _pending_failed_speculation = 0; 1680 _pending_transfer_to_interpreter = false; 1681 _in_retryable_allocation = false; 1682 _jvmci._alternate_call_target = NULL; 1683 assert(_jvmci._implicit_exception_pc == NULL, "must be"); 1684 _jvmci_counters = NULL; 1685 if (JVMCICounterSize > 0) { 1686 resize_counters(0, (int) JVMCICounterSize); 1687 } 1688 #endif // INCLUDE_JVMCI 1689 _reserved_stack_activation = NULL; // stack base not known yet 1690 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1691 _exception_pc = 0; 1692 _exception_handler_pc = 0; 1693 _is_method_handle_return = 0; 1694 _jvmti_thread_state= NULL; 1695 _should_post_on_exceptions_flag = JNI_FALSE; 1696 _interp_only_mode = 0; 1697 _special_runtime_exit_condition = _no_async_condition; 1698 _pending_async_exception = NULL; 1699 _thread_stat = NULL; 1700 _thread_stat = new ThreadStatistics(); 1701 _jni_active_critical = 0; 1702 _pending_jni_exception_check_fn = NULL; 1703 _do_not_unlock_if_synchronized = false; 1704 _cached_monitor_info = NULL; 1705 _parker = Parker::Allocate(this); 1706 _SleepEvent = ParkEvent::Allocate(this); 1707 // Setup safepoint state info for this thread 1708 ThreadSafepointState::create(this); 1709 1710 debug_only(_java_call_counter = 0); 1711 1712 // JVMTI PopFrame support 1713 _popframe_condition = popframe_inactive; 1714 _popframe_preserved_args = NULL; 1715 _popframe_preserved_args_size = 0; 1716 _frames_to_pop_failed_realloc = 0; 1717 1718 if (SafepointMechanism::uses_thread_local_poll()) { 1719 SafepointMechanism::initialize_header(this); 1720 } 1721 1722 _class_to_be_initialized = NULL; 1723 1724 pd_initialize(); 1725 } 1726 1727 JavaThread::JavaThread(bool is_attaching_via_jni) : 1728 Thread() { 1729 initialize(); 1730 if (is_attaching_via_jni) { 1731 _jni_attach_state = _attaching_via_jni; 1732 } else { 1733 _jni_attach_state = _not_attaching_via_jni; 1734 } 1735 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1736 } 1737 1738 1739 // interrupt support 1740 1741 void JavaThread::interrupt() { 1742 debug_only(check_for_dangling_thread_pointer(this);) 1743 1744 // For Windows _interrupt_event 1745 osthread()->set_interrupted(true); 1746 1747 // For Thread.sleep 1748 _SleepEvent->unpark(); 1749 1750 // For JSR166 LockSupport.park 1751 parker()->unpark(); 1752 1753 // For ObjectMonitor and JvmtiRawMonitor 1754 _ParkEvent->unpark(); 1755 } 1756 1757 1758 bool JavaThread::is_interrupted(bool clear_interrupted) { 1759 debug_only(check_for_dangling_thread_pointer(this);) 1760 1761 if (threadObj() == NULL) { 1762 // If there is no j.l.Thread then it is impossible to have 1763 // been interrupted. We can find NULL during VM initialization 1764 // or when a JNI thread is still in the process of attaching. 1765 // In such cases this must be the current thread. 1766 assert(this == Thread::current(), "invariant"); 1767 return false; 1768 } 1769 1770 bool interrupted = java_lang_Thread::interrupted(threadObj()); 1771 1772 // NOTE that since there is no "lock" around the interrupt and 1773 // is_interrupted operations, there is the possibility that the 1774 // interrupted flag will be "false" but that the 1775 // low-level events will be in the signaled state. This is 1776 // intentional. The effect of this is that Object.wait() and 1777 // LockSupport.park() will appear to have a spurious wakeup, which 1778 // is allowed and not harmful, and the possibility is so rare that 1779 // it is not worth the added complexity to add yet another lock. 1780 // For the sleep event an explicit reset is performed on entry 1781 // to JavaThread::sleep, so there is no early return. It has also been 1782 // recommended not to put the interrupted flag into the "event" 1783 // structure because it hides the issue. 1784 // Also, because there is no lock, we must only clear the interrupt 1785 // state if we are going to report that we were interrupted; otherwise 1786 // an interrupt that happens just after we read the field would be lost. 1787 if (interrupted && clear_interrupted) { 1788 assert(this == Thread::current(), "only the current thread can clear"); 1789 java_lang_Thread::set_interrupted(threadObj(), false); 1790 osthread()->set_interrupted(false); 1791 } 1792 1793 return interrupted; 1794 } 1795 1796 bool JavaThread::reguard_stack(address cur_sp) { 1797 if (_stack_guard_state != stack_guard_yellow_reserved_disabled 1798 && _stack_guard_state != stack_guard_reserved_disabled) { 1799 return true; // Stack already guarded or guard pages not needed. 1800 } 1801 1802 if (register_stack_overflow()) { 1803 // For those architectures which have separate register and 1804 // memory stacks, we must check the register stack to see if 1805 // it has overflowed. 1806 return false; 1807 } 1808 1809 // Java code never executes within the yellow zone: the latter is only 1810 // there to provoke an exception during stack banging. If java code 1811 // is executing there, either StackShadowPages should be larger, or 1812 // some exception code in c1, c2 or the interpreter isn't unwinding 1813 // when it should. 1814 guarantee(cur_sp > stack_reserved_zone_base(), 1815 "not enough space to reguard - increase StackShadowPages"); 1816 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) { 1817 enable_stack_yellow_reserved_zone(); 1818 if (reserved_stack_activation() != stack_base()) { 1819 set_reserved_stack_activation(stack_base()); 1820 } 1821 } else if (_stack_guard_state == stack_guard_reserved_disabled) { 1822 set_reserved_stack_activation(stack_base()); 1823 enable_stack_reserved_zone(); 1824 } 1825 return true; 1826 } 1827 1828 bool JavaThread::reguard_stack(void) { 1829 return reguard_stack(os::current_stack_pointer()); 1830 } 1831 1832 1833 void JavaThread::block_if_vm_exited() { 1834 if (_terminated == _vm_exited) { 1835 // _vm_exited is set at safepoint, and Threads_lock is never released 1836 // we will block here forever. 1837 // Here we can be doing a jump from a safe state to an unsafe state without 1838 // proper transition, but it happens after the final safepoint has begun. 1839 set_thread_state(_thread_in_vm); 1840 Threads_lock->lock(); 1841 ShouldNotReachHere(); 1842 } 1843 } 1844 1845 1846 // Remove this ifdef when C1 is ported to the compiler interface. 1847 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1848 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1849 1850 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1851 Thread() { 1852 initialize(); 1853 _jni_attach_state = _not_attaching_via_jni; 1854 set_entry_point(entry_point); 1855 // Create the native thread itself. 1856 // %note runtime_23 1857 os::ThreadType thr_type = os::java_thread; 1858 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1859 os::java_thread; 1860 os::create_thread(this, thr_type, stack_sz); 1861 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1862 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1863 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1864 // the exception consists of creating the exception object & initializing it, initialization 1865 // will leave the VM via a JavaCall and then all locks must be unlocked). 1866 // 1867 // The thread is still suspended when we reach here. Thread must be explicit started 1868 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1869 // by calling Threads:add. The reason why this is not done here, is because the thread 1870 // object must be fully initialized (take a look at JVM_Start) 1871 } 1872 1873 JavaThread::~JavaThread() { 1874 1875 // JSR166 -- return the parker to the free list 1876 Parker::Release(_parker); 1877 _parker = NULL; 1878 1879 // Return the sleep event to the free list 1880 ParkEvent::Release(_SleepEvent); 1881 _SleepEvent = NULL; 1882 1883 // Free any remaining previous UnrollBlock 1884 vframeArray* old_array = vframe_array_last(); 1885 1886 if (old_array != NULL) { 1887 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1888 old_array->set_unroll_block(NULL); 1889 delete old_info; 1890 delete old_array; 1891 } 1892 1893 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1894 if (deferred != NULL) { 1895 // This can only happen if thread is destroyed before deoptimization occurs. 1896 assert(deferred->length() != 0, "empty array!"); 1897 do { 1898 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1899 deferred->remove_at(0); 1900 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1901 delete dlv; 1902 } while (deferred->length() != 0); 1903 delete deferred; 1904 } 1905 1906 // All Java related clean up happens in exit 1907 ThreadSafepointState::destroy(this); 1908 if (_thread_stat != NULL) delete _thread_stat; 1909 1910 #if INCLUDE_JVMCI 1911 if (JVMCICounterSize > 0) { 1912 if (jvmci_counters_include(this)) { 1913 for (int i = 0; i < JVMCICounterSize; i++) { 1914 _jvmci_old_thread_counters[i] += _jvmci_counters[i]; 1915 } 1916 } 1917 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); 1918 } 1919 #endif // INCLUDE_JVMCI 1920 } 1921 1922 1923 // First JavaThread specific code executed by a new Java thread. 1924 void JavaThread::pre_run() { 1925 // empty - see comments in run() 1926 } 1927 1928 // The main routine called by a new Java thread. This isn't overridden 1929 // by subclasses, instead different subclasses define a different "entry_point" 1930 // which defines the actual logic for that kind of thread. 1931 void JavaThread::run() { 1932 // initialize thread-local alloc buffer related fields 1933 this->initialize_tlab(); 1934 1935 // Used to test validity of stack trace backs. 1936 // This can't be moved into pre_run() else we invalidate 1937 // the requirement that thread_main_inner is lower on 1938 // the stack. Consequently all the initialization logic 1939 // stays here in run() rather than pre_run(). 1940 this->record_base_of_stack_pointer(); 1941 1942 this->create_stack_guard_pages(); 1943 1944 this->cache_global_variables(); 1945 1946 // Thread is now sufficiently initialized to be handled by the safepoint code as being 1947 // in the VM. Change thread state from _thread_new to _thread_in_vm 1948 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm); 1949 // Before a thread is on the threads list it is always safe, so after leaving the 1950 // _thread_new we should emit a instruction barrier. The distance to modified code 1951 // from here is probably far enough, but this is consistent and safe. 1952 OrderAccess::cross_modify_fence(); 1953 1954 assert(JavaThread::current() == this, "sanity check"); 1955 assert(!Thread::current()->owns_locks(), "sanity check"); 1956 1957 DTRACE_THREAD_PROBE(start, this); 1958 1959 // This operation might block. We call that after all safepoint checks for a new thread has 1960 // been completed. 1961 this->set_active_handles(JNIHandleBlock::allocate_block()); 1962 1963 if (JvmtiExport::should_post_thread_life()) { 1964 JvmtiExport::post_thread_start(this); 1965 1966 } 1967 1968 // We call another function to do the rest so we are sure that the stack addresses used 1969 // from there will be lower than the stack base just computed. 1970 thread_main_inner(); 1971 } 1972 1973 void JavaThread::thread_main_inner() { 1974 assert(JavaThread::current() == this, "sanity check"); 1975 assert(this->threadObj() != NULL, "just checking"); 1976 1977 // Execute thread entry point unless this thread has a pending exception 1978 // or has been stopped before starting. 1979 // Note: Due to JVM_StopThread we can have pending exceptions already! 1980 if (!this->has_pending_exception() && 1981 !java_lang_Thread::is_stillborn(this->threadObj())) { 1982 { 1983 ResourceMark rm(this); 1984 this->set_native_thread_name(this->get_thread_name()); 1985 } 1986 HandleMark hm(this); 1987 this->entry_point()(this, this); 1988 } 1989 1990 DTRACE_THREAD_PROBE(stop, this); 1991 1992 // Cleanup is handled in post_run() 1993 } 1994 1995 // Shared teardown for all JavaThreads 1996 void JavaThread::post_run() { 1997 this->exit(false); 1998 // Defer deletion to here to ensure 'this' is still referenceable in call_run 1999 // for any shared tear-down. 2000 this->smr_delete(); 2001 } 2002 2003 static void ensure_join(JavaThread* thread) { 2004 // We do not need to grab the Threads_lock, since we are operating on ourself. 2005 Handle threadObj(thread, thread->threadObj()); 2006 assert(threadObj.not_null(), "java thread object must exist"); 2007 ObjectLocker lock(threadObj, thread); 2008 // Ignore pending exception (ThreadDeath), since we are exiting anyway 2009 thread->clear_pending_exception(); 2010 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 2011 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 2012 // Clear the native thread instance - this makes isAlive return false and allows the join() 2013 // to complete once we've done the notify_all below 2014 java_lang_Thread::set_thread(threadObj(), NULL); 2015 lock.notify_all(thread); 2016 // Ignore pending exception (ThreadDeath), since we are exiting anyway 2017 thread->clear_pending_exception(); 2018 } 2019 2020 static bool is_daemon(oop threadObj) { 2021 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)); 2022 } 2023 2024 // For any new cleanup additions, please check to see if they need to be applied to 2025 // cleanup_failed_attach_current_thread as well. 2026 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 2027 assert(this == JavaThread::current(), "thread consistency check"); 2028 2029 elapsedTimer _timer_exit_phase1; 2030 elapsedTimer _timer_exit_phase2; 2031 elapsedTimer _timer_exit_phase3; 2032 elapsedTimer _timer_exit_phase4; 2033 2034 if (log_is_enabled(Debug, os, thread, timer)) { 2035 _timer_exit_phase1.start(); 2036 } 2037 2038 HandleMark hm(this); 2039 Handle uncaught_exception(this, this->pending_exception()); 2040 this->clear_pending_exception(); 2041 Handle threadObj(this, this->threadObj()); 2042 assert(threadObj.not_null(), "Java thread object should be created"); 2043 2044 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 2045 { 2046 EXCEPTION_MARK; 2047 2048 CLEAR_PENDING_EXCEPTION; 2049 } 2050 if (!destroy_vm) { 2051 if (uncaught_exception.not_null()) { 2052 EXCEPTION_MARK; 2053 // Call method Thread.dispatchUncaughtException(). 2054 Klass* thread_klass = SystemDictionary::Thread_klass(); 2055 JavaValue result(T_VOID); 2056 JavaCalls::call_virtual(&result, 2057 threadObj, thread_klass, 2058 vmSymbols::dispatchUncaughtException_name(), 2059 vmSymbols::throwable_void_signature(), 2060 uncaught_exception, 2061 THREAD); 2062 if (HAS_PENDING_EXCEPTION) { 2063 ResourceMark rm(this); 2064 jio_fprintf(defaultStream::error_stream(), 2065 "\nException: %s thrown from the UncaughtExceptionHandler" 2066 " in thread \"%s\"\n", 2067 pending_exception()->klass()->external_name(), 2068 get_thread_name()); 2069 CLEAR_PENDING_EXCEPTION; 2070 } 2071 } 2072 JFR_ONLY(Jfr::on_java_thread_dismantle(this);) 2073 2074 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 2075 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 2076 // is deprecated anyhow. 2077 if (!is_Compiler_thread()) { 2078 int count = 3; 2079 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 2080 EXCEPTION_MARK; 2081 JavaValue result(T_VOID); 2082 Klass* thread_klass = SystemDictionary::Thread_klass(); 2083 JavaCalls::call_virtual(&result, 2084 threadObj, thread_klass, 2085 vmSymbols::exit_method_name(), 2086 vmSymbols::void_method_signature(), 2087 THREAD); 2088 CLEAR_PENDING_EXCEPTION; 2089 } 2090 } 2091 // notify JVMTI 2092 if (JvmtiExport::should_post_thread_life()) { 2093 JvmtiExport::post_thread_end(this); 2094 } 2095 2096 // We have notified the agents that we are exiting, before we go on, 2097 // we must check for a pending external suspend request and honor it 2098 // in order to not surprise the thread that made the suspend request. 2099 while (true) { 2100 { 2101 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2102 if (!is_external_suspend()) { 2103 set_terminated(_thread_exiting); 2104 ThreadService::current_thread_exiting(this, is_daemon(threadObj())); 2105 break; 2106 } 2107 // Implied else: 2108 // Things get a little tricky here. We have a pending external 2109 // suspend request, but we are holding the SR_lock so we 2110 // can't just self-suspend. So we temporarily drop the lock 2111 // and then self-suspend. 2112 } 2113 2114 ThreadBlockInVM tbivm(this); 2115 java_suspend_self(); 2116 2117 // We're done with this suspend request, but we have to loop around 2118 // and check again. Eventually we will get SR_lock without a pending 2119 // external suspend request and will be able to mark ourselves as 2120 // exiting. 2121 } 2122 // no more external suspends are allowed at this point 2123 } else { 2124 assert(!is_terminated() && !is_exiting(), "must not be exiting"); 2125 // before_exit() has already posted JVMTI THREAD_END events 2126 } 2127 2128 if (log_is_enabled(Debug, os, thread, timer)) { 2129 _timer_exit_phase1.stop(); 2130 _timer_exit_phase2.start(); 2131 } 2132 2133 // Capture daemon status before the thread is marked as terminated. 2134 bool daemon = is_daemon(threadObj()); 2135 2136 // Notify waiters on thread object. This has to be done after exit() is called 2137 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 2138 // group should have the destroyed bit set before waiters are notified). 2139 ensure_join(this); 2140 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 2141 2142 if (log_is_enabled(Debug, os, thread, timer)) { 2143 _timer_exit_phase2.stop(); 2144 _timer_exit_phase3.start(); 2145 } 2146 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 2147 // held by this thread must be released. The spec does not distinguish 2148 // between JNI-acquired and regular Java monitors. We can only see 2149 // regular Java monitors here if monitor enter-exit matching is broken. 2150 // 2151 // ensure_join() ignores IllegalThreadStateExceptions, and so does 2152 // ObjectSynchronizer::release_monitors_owned_by_thread(). 2153 if (exit_type == jni_detach) { 2154 // Sanity check even though JNI DetachCurrentThread() would have 2155 // returned JNI_ERR if there was a Java frame. JavaThread exit 2156 // should be done executing Java code by the time we get here. 2157 assert(!this->has_last_Java_frame(), 2158 "should not have a Java frame when detaching or exiting"); 2159 ObjectSynchronizer::release_monitors_owned_by_thread(this); 2160 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 2161 } 2162 2163 // These things needs to be done while we are still a Java Thread. Make sure that thread 2164 // is in a consistent state, in case GC happens 2165 JFR_ONLY(Jfr::on_thread_exit(this);) 2166 2167 if (active_handles() != NULL) { 2168 JNIHandleBlock* block = active_handles(); 2169 set_active_handles(NULL); 2170 JNIHandleBlock::release_block(block); 2171 } 2172 2173 if (free_handle_block() != NULL) { 2174 JNIHandleBlock* block = free_handle_block(); 2175 set_free_handle_block(NULL); 2176 JNIHandleBlock::release_block(block); 2177 } 2178 2179 // These have to be removed while this is still a valid thread. 2180 remove_stack_guard_pages(); 2181 2182 if (UseTLAB) { 2183 tlab().retire(); 2184 } 2185 2186 if (JvmtiEnv::environments_might_exist()) { 2187 JvmtiExport::cleanup_thread(this); 2188 } 2189 2190 // We must flush any deferred card marks and other various GC barrier 2191 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer) 2192 // before removing a thread from the list of active threads. 2193 BarrierSet::barrier_set()->on_thread_detach(this); 2194 2195 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").", 2196 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", 2197 os::current_thread_id()); 2198 2199 if (log_is_enabled(Debug, os, thread, timer)) { 2200 _timer_exit_phase3.stop(); 2201 _timer_exit_phase4.start(); 2202 } 2203 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 2204 Threads::remove(this, daemon); 2205 2206 if (log_is_enabled(Debug, os, thread, timer)) { 2207 _timer_exit_phase4.stop(); 2208 ResourceMark rm(this); 2209 log_debug(os, thread, timer)("name='%s'" 2210 ", exit-phase1=" JLONG_FORMAT 2211 ", exit-phase2=" JLONG_FORMAT 2212 ", exit-phase3=" JLONG_FORMAT 2213 ", exit-phase4=" JLONG_FORMAT, 2214 get_thread_name(), 2215 _timer_exit_phase1.milliseconds(), 2216 _timer_exit_phase2.milliseconds(), 2217 _timer_exit_phase3.milliseconds(), 2218 _timer_exit_phase4.milliseconds()); 2219 } 2220 } 2221 2222 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) { 2223 if (active_handles() != NULL) { 2224 JNIHandleBlock* block = active_handles(); 2225 set_active_handles(NULL); 2226 JNIHandleBlock::release_block(block); 2227 } 2228 2229 if (free_handle_block() != NULL) { 2230 JNIHandleBlock* block = free_handle_block(); 2231 set_free_handle_block(NULL); 2232 JNIHandleBlock::release_block(block); 2233 } 2234 2235 // These have to be removed while this is still a valid thread. 2236 remove_stack_guard_pages(); 2237 2238 if (UseTLAB) { 2239 tlab().retire(); 2240 } 2241 2242 BarrierSet::barrier_set()->on_thread_detach(this); 2243 2244 Threads::remove(this, is_daemon); 2245 this->smr_delete(); 2246 } 2247 2248 JavaThread* JavaThread::active() { 2249 Thread* thread = Thread::current(); 2250 if (thread->is_Java_thread()) { 2251 return (JavaThread*) thread; 2252 } else { 2253 assert(thread->is_VM_thread(), "this must be a vm thread"); 2254 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2255 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2256 assert(ret->is_Java_thread(), "must be a Java thread"); 2257 return ret; 2258 } 2259 } 2260 2261 bool JavaThread::is_lock_owned(address adr) const { 2262 if (Thread::is_lock_owned(adr)) return true; 2263 2264 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2265 if (chunk->contains(adr)) return true; 2266 } 2267 2268 return false; 2269 } 2270 2271 2272 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2273 chunk->set_next(monitor_chunks()); 2274 set_monitor_chunks(chunk); 2275 } 2276 2277 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2278 guarantee(monitor_chunks() != NULL, "must be non empty"); 2279 if (monitor_chunks() == chunk) { 2280 set_monitor_chunks(chunk->next()); 2281 } else { 2282 MonitorChunk* prev = monitor_chunks(); 2283 while (prev->next() != chunk) prev = prev->next(); 2284 prev->set_next(chunk->next()); 2285 } 2286 } 2287 2288 // JVM support. 2289 2290 // Note: this function shouldn't block if it's called in 2291 // _thread_in_native_trans state (such as from 2292 // check_special_condition_for_native_trans()). 2293 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2294 2295 if (has_last_Java_frame() && has_async_condition()) { 2296 // If we are at a polling page safepoint (not a poll return) 2297 // then we must defer async exception because live registers 2298 // will be clobbered by the exception path. Poll return is 2299 // ok because the call we a returning from already collides 2300 // with exception handling registers and so there is no issue. 2301 // (The exception handling path kills call result registers but 2302 // this is ok since the exception kills the result anyway). 2303 2304 if (is_at_poll_safepoint()) { 2305 // if the code we are returning to has deoptimized we must defer 2306 // the exception otherwise live registers get clobbered on the 2307 // exception path before deoptimization is able to retrieve them. 2308 // 2309 RegisterMap map(this, false); 2310 frame caller_fr = last_frame().sender(&map); 2311 assert(caller_fr.is_compiled_frame(), "what?"); 2312 if (caller_fr.is_deoptimized_frame()) { 2313 log_info(exceptions)("deferred async exception at compiled safepoint"); 2314 return; 2315 } 2316 } 2317 } 2318 2319 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2320 if (condition == _no_async_condition) { 2321 // Conditions have changed since has_special_runtime_exit_condition() 2322 // was called: 2323 // - if we were here only because of an external suspend request, 2324 // then that was taken care of above (or cancelled) so we are done 2325 // - if we were here because of another async request, then it has 2326 // been cleared between the has_special_runtime_exit_condition() 2327 // and now so again we are done 2328 return; 2329 } 2330 2331 // Check for pending async. exception 2332 if (_pending_async_exception != NULL) { 2333 // Only overwrite an already pending exception, if it is not a threadDeath. 2334 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2335 2336 // We cannot call Exceptions::_throw(...) here because we cannot block 2337 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2338 2339 LogTarget(Info, exceptions) lt; 2340 if (lt.is_enabled()) { 2341 ResourceMark rm; 2342 LogStream ls(lt); 2343 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); 2344 if (has_last_Java_frame()) { 2345 frame f = last_frame(); 2346 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); 2347 } 2348 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name()); 2349 } 2350 _pending_async_exception = NULL; 2351 clear_has_async_exception(); 2352 } 2353 } 2354 2355 if (check_unsafe_error && 2356 condition == _async_unsafe_access_error && !has_pending_exception()) { 2357 condition = _no_async_condition; // done 2358 switch (thread_state()) { 2359 case _thread_in_vm: { 2360 JavaThread* THREAD = this; 2361 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2362 } 2363 case _thread_in_native: { 2364 ThreadInVMfromNative tiv(this); 2365 JavaThread* THREAD = this; 2366 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2367 } 2368 case _thread_in_Java: { 2369 ThreadInVMfromJava tiv(this); 2370 JavaThread* THREAD = this; 2371 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2372 } 2373 default: 2374 ShouldNotReachHere(); 2375 } 2376 } 2377 2378 assert(condition == _no_async_condition || has_pending_exception() || 2379 (!check_unsafe_error && condition == _async_unsafe_access_error), 2380 "must have handled the async condition, if no exception"); 2381 } 2382 2383 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2384 2385 // Check for pending external suspend. 2386 if (is_external_suspend_with_lock()) { 2387 frame_anchor()->make_walkable(this); 2388 java_suspend_self_with_safepoint_check(); 2389 } 2390 2391 // We might be here for reasons in addition to the self-suspend request 2392 // so check for other async requests. 2393 if (check_asyncs) { 2394 check_and_handle_async_exceptions(); 2395 } 2396 2397 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);) 2398 } 2399 2400 void JavaThread::send_thread_stop(oop java_throwable) { 2401 ResourceMark rm; 2402 assert(Thread::current()->is_VM_thread() || Thread::current() == this, "should be in the vm thread"); 2403 2404 // Do not throw asynchronous exceptions against the compiler thread 2405 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2406 if (!can_call_java()) return; 2407 2408 { 2409 // Actually throw the Throwable against the target Thread - however 2410 // only if there is no thread death exception installed already. 2411 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2412 // If the topmost frame is a runtime stub, then we are calling into 2413 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2414 // must deoptimize the caller before continuing, as the compiled exception handler table 2415 // may not be valid 2416 if (has_last_Java_frame()) { 2417 frame f = last_frame(); 2418 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2419 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2420 RegisterMap reg_map(this, UseBiasedLocking); 2421 frame compiled_frame = f.sender(®_map); 2422 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2423 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2424 } 2425 } 2426 } 2427 2428 // Set async. pending exception in thread. 2429 set_pending_async_exception(java_throwable); 2430 2431 if (log_is_enabled(Info, exceptions)) { 2432 ResourceMark rm; 2433 log_info(exceptions)("Pending Async. exception installed of type: %s", 2434 InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2435 } 2436 // for AbortVMOnException flag 2437 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name()); 2438 } 2439 } 2440 2441 2442 // Interrupt thread so it will wake up from a potential wait()/sleep()/park() 2443 java_lang_Thread::set_interrupted(threadObj(), true); 2444 this->interrupt(); 2445 } 2446 2447 // External suspension mechanism. 2448 // 2449 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2450 // to any VM_locks and it is at a transition 2451 // Self-suspension will happen on the transition out of the vm. 2452 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2453 // 2454 // Guarantees on return: 2455 // + Target thread will not execute any new bytecode (that's why we need to 2456 // force a safepoint) 2457 // + Target thread will not enter any new monitors 2458 // 2459 void JavaThread::java_suspend() { 2460 ThreadsListHandle tlh; 2461 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) { 2462 return; 2463 } 2464 2465 { MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2466 if (!is_external_suspend()) { 2467 // a racing resume has cancelled us; bail out now 2468 return; 2469 } 2470 2471 // suspend is done 2472 uint32_t debug_bits = 0; 2473 // Warning: is_ext_suspend_completed() may temporarily drop the 2474 // SR_lock to allow the thread to reach a stable thread state if 2475 // it is currently in a transient thread state. 2476 if (is_ext_suspend_completed(false /* !called_by_wait */, 2477 SuspendRetryDelay, &debug_bits)) { 2478 return; 2479 } 2480 } 2481 2482 if (Thread::current() == this) { 2483 // Safely self-suspend. 2484 // If we don't do this explicitly it will implicitly happen 2485 // before we transition back to Java, and on some other thread-state 2486 // transition paths, but not as we exit a JVM TI SuspendThread call. 2487 // As SuspendThread(current) must not return (until resumed) we must 2488 // self-suspend here. 2489 ThreadBlockInVM tbivm(this); 2490 java_suspend_self(); 2491 } else { 2492 VM_ThreadSuspend vm_suspend; 2493 VMThread::execute(&vm_suspend); 2494 } 2495 } 2496 2497 // Part II of external suspension. 2498 // A JavaThread self suspends when it detects a pending external suspend 2499 // request. This is usually on transitions. It is also done in places 2500 // where continuing to the next transition would surprise the caller, 2501 // e.g., monitor entry. 2502 // 2503 // Returns the number of times that the thread self-suspended. 2504 // 2505 // Note: DO NOT call java_suspend_self() when you just want to block current 2506 // thread. java_suspend_self() is the second stage of cooperative 2507 // suspension for external suspend requests and should only be used 2508 // to complete an external suspend request. 2509 // 2510 int JavaThread::java_suspend_self() { 2511 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()"); 2512 int ret = 0; 2513 2514 // we are in the process of exiting so don't suspend 2515 if (is_exiting()) { 2516 clear_external_suspend(); 2517 return ret; 2518 } 2519 2520 assert(_anchor.walkable() || 2521 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2522 "must have walkable stack"); 2523 2524 MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2525 2526 assert(!this->is_ext_suspended(), 2527 "a thread trying to self-suspend should not already be suspended"); 2528 2529 if (this->is_suspend_equivalent()) { 2530 // If we are self-suspending as a result of the lifting of a 2531 // suspend equivalent condition, then the suspend_equivalent 2532 // flag is not cleared until we set the ext_suspended flag so 2533 // that wait_for_ext_suspend_completion() returns consistent 2534 // results. 2535 this->clear_suspend_equivalent(); 2536 } 2537 2538 // A racing resume may have cancelled us before we grabbed SR_lock 2539 // above. Or another external suspend request could be waiting for us 2540 // by the time we return from SR_lock()->wait(). The thread 2541 // that requested the suspension may already be trying to walk our 2542 // stack and if we return now, we can change the stack out from under 2543 // it. This would be a "bad thing (TM)" and cause the stack walker 2544 // to crash. We stay self-suspended until there are no more pending 2545 // external suspend requests. 2546 while (is_external_suspend()) { 2547 ret++; 2548 this->set_ext_suspended(); 2549 2550 // _ext_suspended flag is cleared by java_resume() 2551 while (is_ext_suspended()) { 2552 ml.wait(); 2553 } 2554 } 2555 return ret; 2556 } 2557 2558 // Helper routine to set up the correct thread state before calling java_suspend_self. 2559 // This is called when regular thread-state transition helpers can't be used because 2560 // we can be in various states, in particular _thread_in_native_trans. 2561 // Because this thread is external suspended the safepoint code will count it as at 2562 // a safepoint, regardless of what its actual current thread-state is. But 2563 // is_ext_suspend_completed() may be waiting to see a thread transition from 2564 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly 2565 // to _thread_blocked. The problem with setting thread state directly is that a 2566 // safepoint could happen just after java_suspend_self() returns after being resumed, 2567 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint 2568 // after restoring the state to make sure we won't leave while a safepoint is in progress. 2569 // However, not all initial-states are allowed when performing a safepoint check, as we 2570 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states 2571 // only _thread_in_native is possible when executing this code (based on our two callers). 2572 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter 2573 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state, 2574 // and so we don't need the explicit safepoint check. 2575 2576 void JavaThread::java_suspend_self_with_safepoint_check() { 2577 assert(this == Thread::current(), "invariant"); 2578 JavaThreadState state = thread_state(); 2579 set_thread_state(_thread_blocked); 2580 java_suspend_self(); 2581 set_thread_state_fence(state); 2582 // Since we are not using a regular thread-state transition helper here, 2583 // we must manually emit the instruction barrier after leaving a safe state. 2584 OrderAccess::cross_modify_fence(); 2585 if (state != _thread_in_native) { 2586 SafepointMechanism::block_if_requested(this); 2587 } 2588 } 2589 2590 #ifdef ASSERT 2591 // Verify the JavaThread has not yet been published in the Threads::list, and 2592 // hence doesn't need protection from concurrent access at this stage. 2593 void JavaThread::verify_not_published() { 2594 // Cannot create a ThreadsListHandle here and check !tlh.includes(this) 2595 // since an unpublished JavaThread doesn't participate in the 2596 // Thread-SMR protocol for keeping a ThreadsList alive. 2597 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!"); 2598 } 2599 #endif 2600 2601 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2602 // progress or when _suspend_flags is non-zero. 2603 // Current thread needs to self-suspend if there is a suspend request and/or 2604 // block if a safepoint is in progress. 2605 // Async exception ISN'T checked. 2606 // Note only the ThreadInVMfromNative transition can call this function 2607 // directly and when thread state is _thread_in_native_trans 2608 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2609 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2610 2611 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2612 2613 if (thread->is_external_suspend()) { 2614 thread->java_suspend_self_with_safepoint_check(); 2615 } else { 2616 SafepointMechanism::block_if_requested(thread); 2617 } 2618 2619 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);) 2620 } 2621 2622 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2623 // progress or when _suspend_flags is non-zero. 2624 // Current thread needs to self-suspend if there is a suspend request and/or 2625 // block if a safepoint is in progress. 2626 // Also check for pending async exception (not including unsafe access error). 2627 // Note only the native==>VM/Java barriers can call this function and when 2628 // thread state is _thread_in_native_trans. 2629 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2630 check_safepoint_and_suspend_for_native_trans(thread); 2631 2632 if (thread->has_async_exception()) { 2633 // We are in _thread_in_native_trans state, don't handle unsafe 2634 // access error since that may block. 2635 thread->check_and_handle_async_exceptions(false); 2636 } 2637 } 2638 2639 // This is a variant of the normal 2640 // check_special_condition_for_native_trans with slightly different 2641 // semantics for use by critical native wrappers. It does all the 2642 // normal checks but also performs the transition back into 2643 // thread_in_Java state. This is required so that critical natives 2644 // can potentially block and perform a GC if they are the last thread 2645 // exiting the GCLocker. 2646 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2647 check_special_condition_for_native_trans(thread); 2648 2649 // Finish the transition 2650 thread->set_thread_state(_thread_in_Java); 2651 2652 if (thread->do_critical_native_unlock()) { 2653 ThreadInVMfromJavaNoAsyncException tiv(thread); 2654 GCLocker::unlock_critical(thread); 2655 thread->clear_critical_native_unlock(); 2656 } 2657 } 2658 2659 // We need to guarantee the Threads_lock here, since resumes are not 2660 // allowed during safepoint synchronization 2661 // Can only resume from an external suspension 2662 void JavaThread::java_resume() { 2663 assert_locked_or_safepoint(Threads_lock); 2664 2665 // Sanity check: thread is gone, has started exiting or the thread 2666 // was not externally suspended. 2667 ThreadsListHandle tlh; 2668 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) { 2669 return; 2670 } 2671 2672 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2673 2674 clear_external_suspend(); 2675 2676 if (is_ext_suspended()) { 2677 clear_ext_suspended(); 2678 SR_lock()->notify_all(); 2679 } 2680 } 2681 2682 size_t JavaThread::_stack_red_zone_size = 0; 2683 size_t JavaThread::_stack_yellow_zone_size = 0; 2684 size_t JavaThread::_stack_reserved_zone_size = 0; 2685 size_t JavaThread::_stack_shadow_zone_size = 0; 2686 2687 void JavaThread::create_stack_guard_pages() { 2688 if (!os::uses_stack_guard_pages() || 2689 _stack_guard_state != stack_guard_unused || 2690 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) { 2691 log_info(os, thread)("Stack guard page creation for thread " 2692 UINTX_FORMAT " disabled", os::current_thread_id()); 2693 return; 2694 } 2695 address low_addr = stack_end(); 2696 size_t len = stack_guard_zone_size(); 2697 2698 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page"); 2699 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size"); 2700 2701 int must_commit = os::must_commit_stack_guard_pages(); 2702 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2703 2704 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) { 2705 log_warning(os, thread)("Attempt to allocate stack guard pages failed."); 2706 return; 2707 } 2708 2709 if (os::guard_memory((char *) low_addr, len)) { 2710 _stack_guard_state = stack_guard_enabled; 2711 } else { 2712 log_warning(os, thread)("Attempt to protect stack guard pages failed (" 2713 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2714 if (os::uncommit_memory((char *) low_addr, len)) { 2715 log_warning(os, thread)("Attempt to deallocate stack guard pages failed."); 2716 } 2717 return; 2718 } 2719 2720 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: " 2721 PTR_FORMAT "-" PTR_FORMAT ".", 2722 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2723 } 2724 2725 void JavaThread::remove_stack_guard_pages() { 2726 assert(Thread::current() == this, "from different thread"); 2727 if (_stack_guard_state == stack_guard_unused) return; 2728 address low_addr = stack_end(); 2729 size_t len = stack_guard_zone_size(); 2730 2731 if (os::must_commit_stack_guard_pages()) { 2732 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2733 _stack_guard_state = stack_guard_unused; 2734 } else { 2735 log_warning(os, thread)("Attempt to deallocate stack guard pages failed (" 2736 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2737 return; 2738 } 2739 } else { 2740 if (_stack_guard_state == stack_guard_unused) return; 2741 if (os::unguard_memory((char *) low_addr, len)) { 2742 _stack_guard_state = stack_guard_unused; 2743 } else { 2744 log_warning(os, thread)("Attempt to unprotect stack guard pages failed (" 2745 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2746 return; 2747 } 2748 } 2749 2750 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: " 2751 PTR_FORMAT "-" PTR_FORMAT ".", 2752 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2753 } 2754 2755 void JavaThread::enable_stack_reserved_zone() { 2756 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state"); 2757 2758 // The base notation is from the stack's point of view, growing downward. 2759 // We need to adjust it to work correctly with guard_memory() 2760 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2761 2762 guarantee(base < stack_base(),"Error calculating stack reserved zone"); 2763 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone"); 2764 2765 if (os::guard_memory((char *) base, stack_reserved_zone_size())) { 2766 _stack_guard_state = stack_guard_enabled; 2767 } else { 2768 warning("Attempt to guard stack reserved zone failed."); 2769 } 2770 enable_register_stack_guard(); 2771 } 2772 2773 void JavaThread::disable_stack_reserved_zone() { 2774 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state"); 2775 2776 // Simply return if called for a thread that does not use guard pages. 2777 if (_stack_guard_state != stack_guard_enabled) return; 2778 2779 // The base notation is from the stack's point of view, growing downward. 2780 // We need to adjust it to work correctly with guard_memory() 2781 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2782 2783 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) { 2784 _stack_guard_state = stack_guard_reserved_disabled; 2785 } else { 2786 warning("Attempt to unguard stack reserved zone failed."); 2787 } 2788 disable_register_stack_guard(); 2789 } 2790 2791 void JavaThread::enable_stack_yellow_reserved_zone() { 2792 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2793 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2794 2795 // The base notation is from the stacks point of view, growing downward. 2796 // We need to adjust it to work correctly with guard_memory() 2797 address base = stack_red_zone_base(); 2798 2799 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2800 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2801 2802 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) { 2803 _stack_guard_state = stack_guard_enabled; 2804 } else { 2805 warning("Attempt to guard stack yellow zone failed."); 2806 } 2807 enable_register_stack_guard(); 2808 } 2809 2810 void JavaThread::disable_stack_yellow_reserved_zone() { 2811 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2812 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled"); 2813 2814 // Simply return if called for a thread that does not use guard pages. 2815 if (_stack_guard_state == stack_guard_unused) return; 2816 2817 // The base notation is from the stacks point of view, growing downward. 2818 // We need to adjust it to work correctly with guard_memory() 2819 address base = stack_red_zone_base(); 2820 2821 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) { 2822 _stack_guard_state = stack_guard_yellow_reserved_disabled; 2823 } else { 2824 warning("Attempt to unguard stack yellow zone failed."); 2825 } 2826 disable_register_stack_guard(); 2827 } 2828 2829 void JavaThread::enable_stack_red_zone() { 2830 // The base notation is from the stacks point of view, growing downward. 2831 // We need to adjust it to work correctly with guard_memory() 2832 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2833 address base = stack_red_zone_base() - stack_red_zone_size(); 2834 2835 guarantee(base < stack_base(), "Error calculating stack red zone"); 2836 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2837 2838 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2839 warning("Attempt to guard stack red zone failed."); 2840 } 2841 } 2842 2843 void JavaThread::disable_stack_red_zone() { 2844 // The base notation is from the stacks point of view, growing downward. 2845 // We need to adjust it to work correctly with guard_memory() 2846 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2847 address base = stack_red_zone_base() - stack_red_zone_size(); 2848 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2849 warning("Attempt to unguard stack red zone failed."); 2850 } 2851 } 2852 2853 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2854 // ignore is there is no stack 2855 if (!has_last_Java_frame()) return; 2856 // traverse the stack frames. Starts from top frame. 2857 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2858 frame* fr = fst.current(); 2859 f(fr, fst.register_map()); 2860 } 2861 } 2862 2863 2864 #ifndef PRODUCT 2865 // Deoptimization 2866 // Function for testing deoptimization 2867 void JavaThread::deoptimize() { 2868 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2869 StackFrameStream fst(this, UseBiasedLocking); 2870 bool deopt = false; // Dump stack only if a deopt actually happens. 2871 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2872 // Iterate over all frames in the thread and deoptimize 2873 for (; !fst.is_done(); fst.next()) { 2874 if (fst.current()->can_be_deoptimized()) { 2875 2876 if (only_at) { 2877 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2878 // consists of comma or carriage return separated numbers so 2879 // search for the current bci in that string. 2880 address pc = fst.current()->pc(); 2881 nmethod* nm = (nmethod*) fst.current()->cb(); 2882 ScopeDesc* sd = nm->scope_desc_at(pc); 2883 char buffer[8]; 2884 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2885 size_t len = strlen(buffer); 2886 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2887 while (found != NULL) { 2888 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2889 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2890 // Check that the bci found is bracketed by terminators. 2891 break; 2892 } 2893 found = strstr(found + 1, buffer); 2894 } 2895 if (!found) { 2896 continue; 2897 } 2898 } 2899 2900 if (DebugDeoptimization && !deopt) { 2901 deopt = true; // One-time only print before deopt 2902 tty->print_cr("[BEFORE Deoptimization]"); 2903 trace_frames(); 2904 trace_stack(); 2905 } 2906 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2907 } 2908 } 2909 2910 if (DebugDeoptimization && deopt) { 2911 tty->print_cr("[AFTER Deoptimization]"); 2912 trace_frames(); 2913 } 2914 } 2915 2916 2917 // Make zombies 2918 void JavaThread::make_zombies() { 2919 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2920 if (fst.current()->can_be_deoptimized()) { 2921 // it is a Java nmethod 2922 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2923 nm->make_not_entrant(); 2924 } 2925 } 2926 } 2927 #endif // PRODUCT 2928 2929 2930 void JavaThread::deoptimize_marked_methods() { 2931 if (!has_last_Java_frame()) return; 2932 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2933 StackFrameStream fst(this, UseBiasedLocking); 2934 for (; !fst.is_done(); fst.next()) { 2935 if (fst.current()->should_be_deoptimized()) { 2936 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2937 } 2938 } 2939 } 2940 2941 // If the caller is a NamedThread, then remember, in the current scope, 2942 // the given JavaThread in its _processed_thread field. 2943 class RememberProcessedThread: public StackObj { 2944 NamedThread* _cur_thr; 2945 public: 2946 RememberProcessedThread(JavaThread* jthr) { 2947 Thread* thread = Thread::current(); 2948 if (thread->is_Named_thread()) { 2949 _cur_thr = (NamedThread *)thread; 2950 _cur_thr->set_processed_thread(jthr); 2951 } else { 2952 _cur_thr = NULL; 2953 } 2954 } 2955 2956 ~RememberProcessedThread() { 2957 if (_cur_thr) { 2958 _cur_thr->set_processed_thread(NULL); 2959 } 2960 } 2961 }; 2962 2963 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 2964 // Verify that the deferred card marks have been flushed. 2965 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2966 2967 // Traverse the GCHandles 2968 Thread::oops_do(f, cf); 2969 2970 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2971 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2972 2973 if (has_last_Java_frame()) { 2974 // Record JavaThread to GC thread 2975 RememberProcessedThread rpt(this); 2976 2977 // traverse the registered growable array 2978 if (_array_for_gc != NULL) { 2979 for (int index = 0; index < _array_for_gc->length(); index++) { 2980 f->do_oop(_array_for_gc->adr_at(index)); 2981 } 2982 } 2983 2984 // Traverse the monitor chunks 2985 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2986 chunk->oops_do(f); 2987 } 2988 2989 // Traverse the execution stack 2990 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2991 fst.current()->oops_do(f, cf, fst.register_map()); 2992 } 2993 } 2994 2995 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2996 // If we have deferred set_locals there might be oops waiting to be 2997 // written 2998 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2999 if (list != NULL) { 3000 for (int i = 0; i < list->length(); i++) { 3001 list->at(i)->oops_do(f); 3002 } 3003 } 3004 3005 // Traverse instance variables at the end since the GC may be moving things 3006 // around using this function 3007 f->do_oop((oop*) &_threadObj); 3008 f->do_oop((oop*) &_vm_result); 3009 f->do_oop((oop*) &_exception_oop); 3010 f->do_oop((oop*) &_pending_async_exception); 3011 3012 if (jvmti_thread_state() != NULL) { 3013 jvmti_thread_state()->oops_do(f, cf); 3014 } 3015 } 3016 3017 #ifdef ASSERT 3018 void JavaThread::verify_states_for_handshake() { 3019 // This checks that the thread has a correct frame state during a handshake. 3020 assert((!has_last_Java_frame() && java_call_counter() == 0) || 3021 (has_last_Java_frame() && java_call_counter() > 0), 3022 "unexpected frame info: has_last_frame=%d, java_call_counter=%d", 3023 has_last_Java_frame(), java_call_counter()); 3024 } 3025 #endif 3026 3027 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 3028 assert((!has_last_Java_frame() && java_call_counter() == 0) || 3029 (has_last_Java_frame() && java_call_counter() > 0), 3030 "unexpected frame info: has_last_frame=%d, java_call_counter=%d", 3031 has_last_Java_frame(), java_call_counter()); 3032 3033 if (has_last_Java_frame()) { 3034 // Traverse the execution stack 3035 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3036 fst.current()->nmethods_do(cf); 3037 } 3038 } 3039 3040 if (jvmti_thread_state() != NULL) { 3041 jvmti_thread_state()->nmethods_do(cf); 3042 } 3043 } 3044 3045 void JavaThread::metadata_do(MetadataClosure* f) { 3046 if (has_last_Java_frame()) { 3047 // Traverse the execution stack to call f() on the methods in the stack 3048 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3049 fst.current()->metadata_do(f); 3050 } 3051 } else if (is_Compiler_thread()) { 3052 // need to walk ciMetadata in current compile tasks to keep alive. 3053 CompilerThread* ct = (CompilerThread*)this; 3054 if (ct->env() != NULL) { 3055 ct->env()->metadata_do(f); 3056 } 3057 CompileTask* task = ct->task(); 3058 if (task != NULL) { 3059 task->metadata_do(f); 3060 } 3061 } 3062 } 3063 3064 // Printing 3065 const char* _get_thread_state_name(JavaThreadState _thread_state) { 3066 switch (_thread_state) { 3067 case _thread_uninitialized: return "_thread_uninitialized"; 3068 case _thread_new: return "_thread_new"; 3069 case _thread_new_trans: return "_thread_new_trans"; 3070 case _thread_in_native: return "_thread_in_native"; 3071 case _thread_in_native_trans: return "_thread_in_native_trans"; 3072 case _thread_in_vm: return "_thread_in_vm"; 3073 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 3074 case _thread_in_Java: return "_thread_in_Java"; 3075 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 3076 case _thread_blocked: return "_thread_blocked"; 3077 case _thread_blocked_trans: return "_thread_blocked_trans"; 3078 default: return "unknown thread state"; 3079 } 3080 } 3081 3082 #ifndef PRODUCT 3083 void JavaThread::print_thread_state_on(outputStream *st) const { 3084 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 3085 }; 3086 #endif // PRODUCT 3087 3088 // Called by Threads::print() for VM_PrintThreads operation 3089 void JavaThread::print_on(outputStream *st, bool print_extended_info) const { 3090 st->print_raw("\""); 3091 st->print_raw(get_thread_name()); 3092 st->print_raw("\" "); 3093 oop thread_oop = threadObj(); 3094 if (thread_oop != NULL) { 3095 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop)); 3096 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 3097 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 3098 } 3099 Thread::print_on(st, print_extended_info); 3100 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 3101 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 3102 if (thread_oop != NULL) { 3103 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 3104 } 3105 #ifndef PRODUCT 3106 _safepoint_state->print_on(st); 3107 #endif // PRODUCT 3108 if (is_Compiler_thread()) { 3109 CompileTask *task = ((CompilerThread*)this)->task(); 3110 if (task != NULL) { 3111 st->print(" Compiling: "); 3112 task->print(st, NULL, true, false); 3113 } else { 3114 st->print(" No compile task"); 3115 } 3116 st->cr(); 3117 } 3118 } 3119 3120 void JavaThread::print() const { print_on(tty); } 3121 3122 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const { 3123 st->print("%s", get_thread_name_string(buf, buflen)); 3124 } 3125 3126 // Called by fatal error handler. The difference between this and 3127 // JavaThread::print() is that we can't grab lock or allocate memory. 3128 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 3129 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 3130 oop thread_obj = threadObj(); 3131 if (thread_obj != NULL) { 3132 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 3133 } 3134 st->print(" ["); 3135 st->print("%s", _get_thread_state_name(_thread_state)); 3136 if (osthread()) { 3137 st->print(", id=%d", osthread()->thread_id()); 3138 } 3139 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 3140 p2i(stack_end()), p2i(stack_base())); 3141 st->print("]"); 3142 3143 ThreadsSMRSupport::print_info_on(this, st); 3144 return; 3145 } 3146 3147 // Verification 3148 3149 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 3150 3151 void JavaThread::verify() { 3152 // Verify oops in the thread. 3153 oops_do(&VerifyOopClosure::verify_oop, NULL); 3154 3155 // Verify the stack frames. 3156 frames_do(frame_verify); 3157 } 3158 3159 // CR 6300358 (sub-CR 2137150) 3160 // Most callers of this method assume that it can't return NULL but a 3161 // thread may not have a name whilst it is in the process of attaching to 3162 // the VM - see CR 6412693, and there are places where a JavaThread can be 3163 // seen prior to having it's threadObj set (eg JNI attaching threads and 3164 // if vm exit occurs during initialization). These cases can all be accounted 3165 // for such that this method never returns NULL. 3166 const char* JavaThread::get_thread_name() const { 3167 #ifdef ASSERT 3168 // early safepoints can hit while current thread does not yet have TLS 3169 if (!SafepointSynchronize::is_at_safepoint()) { 3170 Thread *cur = Thread::current(); 3171 if (!(cur->is_Java_thread() && cur == this)) { 3172 // Current JavaThreads are allowed to get their own name without 3173 // the Threads_lock. 3174 assert_locked_or_safepoint_or_handshake(Threads_lock, this); 3175 } 3176 } 3177 #endif // ASSERT 3178 return get_thread_name_string(); 3179 } 3180 3181 // Returns a non-NULL representation of this thread's name, or a suitable 3182 // descriptive string if there is no set name 3183 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 3184 const char* name_str; 3185 oop thread_obj = threadObj(); 3186 if (thread_obj != NULL) { 3187 oop name = java_lang_Thread::name(thread_obj); 3188 if (name != NULL) { 3189 if (buf == NULL) { 3190 name_str = java_lang_String::as_utf8_string(name); 3191 } else { 3192 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 3193 } 3194 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 3195 name_str = "<no-name - thread is attaching>"; 3196 } else { 3197 name_str = Thread::name(); 3198 } 3199 } else { 3200 name_str = Thread::name(); 3201 } 3202 assert(name_str != NULL, "unexpected NULL thread name"); 3203 return name_str; 3204 } 3205 3206 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 3207 3208 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3209 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check"); 3210 // Link Java Thread object <-> C++ Thread 3211 3212 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3213 // and put it into a new Handle. The Handle "thread_oop" can then 3214 // be used to pass the C++ thread object to other methods. 3215 3216 // Set the Java level thread object (jthread) field of the 3217 // new thread (a JavaThread *) to C++ thread object using the 3218 // "thread_oop" handle. 3219 3220 // Set the thread field (a JavaThread *) of the 3221 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3222 3223 Handle thread_oop(Thread::current(), 3224 JNIHandles::resolve_non_null(jni_thread)); 3225 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3226 "must be initialized"); 3227 set_threadObj(thread_oop()); 3228 java_lang_Thread::set_thread(thread_oop(), this); 3229 3230 if (prio == NoPriority) { 3231 prio = java_lang_Thread::priority(thread_oop()); 3232 assert(prio != NoPriority, "A valid priority should be present"); 3233 } 3234 3235 // Push the Java priority down to the native thread; needs Threads_lock 3236 Thread::set_priority(this, prio); 3237 3238 // Add the new thread to the Threads list and set it in motion. 3239 // We must have threads lock in order to call Threads::add. 3240 // It is crucial that we do not block before the thread is 3241 // added to the Threads list for if a GC happens, then the java_thread oop 3242 // will not be visited by GC. 3243 Threads::add(this); 3244 } 3245 3246 oop JavaThread::current_park_blocker() { 3247 // Support for JSR-166 locks 3248 oop thread_oop = threadObj(); 3249 if (thread_oop != NULL) { 3250 return java_lang_Thread::park_blocker(thread_oop); 3251 } 3252 return NULL; 3253 } 3254 3255 3256 void JavaThread::print_stack_on(outputStream* st) { 3257 if (!has_last_Java_frame()) return; 3258 ResourceMark rm; 3259 HandleMark hm; 3260 3261 RegisterMap reg_map(this); 3262 vframe* start_vf = last_java_vframe(®_map); 3263 int count = 0; 3264 for (vframe* f = start_vf; f != NULL; f = f->sender()) { 3265 if (f->is_java_frame()) { 3266 javaVFrame* jvf = javaVFrame::cast(f); 3267 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3268 3269 // Print out lock information 3270 if (JavaMonitorsInStackTrace) { 3271 jvf->print_lock_info_on(st, count); 3272 } 3273 } else { 3274 // Ignore non-Java frames 3275 } 3276 3277 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0 3278 count++; 3279 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return; 3280 } 3281 } 3282 3283 3284 // JVMTI PopFrame support 3285 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3286 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3287 if (in_bytes(size_in_bytes) != 0) { 3288 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3289 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3290 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3291 } 3292 } 3293 3294 void* JavaThread::popframe_preserved_args() { 3295 return _popframe_preserved_args; 3296 } 3297 3298 ByteSize JavaThread::popframe_preserved_args_size() { 3299 return in_ByteSize(_popframe_preserved_args_size); 3300 } 3301 3302 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3303 int sz = in_bytes(popframe_preserved_args_size()); 3304 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3305 return in_WordSize(sz / wordSize); 3306 } 3307 3308 void JavaThread::popframe_free_preserved_args() { 3309 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3310 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args); 3311 _popframe_preserved_args = NULL; 3312 _popframe_preserved_args_size = 0; 3313 } 3314 3315 #ifndef PRODUCT 3316 3317 void JavaThread::trace_frames() { 3318 tty->print_cr("[Describe stack]"); 3319 int frame_no = 1; 3320 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3321 tty->print(" %d. ", frame_no++); 3322 fst.current()->print_value_on(tty, this); 3323 tty->cr(); 3324 } 3325 } 3326 3327 class PrintAndVerifyOopClosure: public OopClosure { 3328 protected: 3329 template <class T> inline void do_oop_work(T* p) { 3330 oop obj = RawAccess<>::oop_load(p); 3331 if (obj == NULL) return; 3332 tty->print(INTPTR_FORMAT ": ", p2i(p)); 3333 if (oopDesc::is_oop_or_null(obj)) { 3334 if (obj->is_objArray()) { 3335 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); 3336 } else { 3337 obj->print(); 3338 } 3339 } else { 3340 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); 3341 } 3342 tty->cr(); 3343 } 3344 public: 3345 virtual void do_oop(oop* p) { do_oop_work(p); } 3346 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3347 }; 3348 3349 #ifdef ASSERT 3350 // Print or validate the layout of stack frames 3351 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3352 ResourceMark rm; 3353 PRESERVE_EXCEPTION_MARK; 3354 FrameValues values; 3355 int frame_no = 0; 3356 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3357 fst.current()->describe(values, ++frame_no); 3358 if (depth == frame_no) break; 3359 } 3360 if (validate_only) { 3361 values.validate(); 3362 } else { 3363 tty->print_cr("[Describe stack layout]"); 3364 values.print(this); 3365 } 3366 } 3367 #endif 3368 3369 void JavaThread::trace_stack_from(vframe* start_vf) { 3370 ResourceMark rm; 3371 int vframe_no = 1; 3372 for (vframe* f = start_vf; f; f = f->sender()) { 3373 if (f->is_java_frame()) { 3374 javaVFrame::cast(f)->print_activation(vframe_no++); 3375 } else { 3376 f->print(); 3377 } 3378 if (vframe_no > StackPrintLimit) { 3379 tty->print_cr("...<more frames>..."); 3380 return; 3381 } 3382 } 3383 } 3384 3385 3386 void JavaThread::trace_stack() { 3387 if (!has_last_Java_frame()) return; 3388 ResourceMark rm; 3389 HandleMark hm; 3390 RegisterMap reg_map(this); 3391 trace_stack_from(last_java_vframe(®_map)); 3392 } 3393 3394 3395 #endif // PRODUCT 3396 3397 3398 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3399 assert(reg_map != NULL, "a map must be given"); 3400 frame f = last_frame(); 3401 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3402 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3403 } 3404 return NULL; 3405 } 3406 3407 3408 Klass* JavaThread::security_get_caller_class(int depth) { 3409 vframeStream vfst(this); 3410 vfst.security_get_caller_frame(depth); 3411 if (!vfst.at_end()) { 3412 return vfst.method()->method_holder(); 3413 } 3414 return NULL; 3415 } 3416 3417 // java.lang.Thread.sleep support 3418 // Returns true if sleep time elapsed as expected, and false 3419 // if the thread was interrupted. 3420 bool JavaThread::sleep(jlong millis) { 3421 assert(this == Thread::current(), "thread consistency check"); 3422 3423 ParkEvent * const slp = this->_SleepEvent; 3424 // Because there can be races with thread interruption sending an unpark() 3425 // to the event, we explicitly reset it here to avoid an immediate return. 3426 // The actual interrupt state will be checked before we park(). 3427 slp->reset(); 3428 // Thread interruption establishes a happens-before ordering in the 3429 // Java Memory Model, so we need to ensure we synchronize with the 3430 // interrupt state. 3431 OrderAccess::fence(); 3432 3433 jlong prevtime = os::javaTimeNanos(); 3434 3435 for (;;) { 3436 // interruption has precedence over timing out 3437 if (this->is_interrupted(true)) { 3438 return false; 3439 } 3440 3441 if (millis <= 0) { 3442 return true; 3443 } 3444 3445 { 3446 ThreadBlockInVM tbivm(this); 3447 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 3448 3449 this->set_suspend_equivalent(); 3450 // cleared by handle_special_suspend_equivalent_condition() or 3451 // java_suspend_self() via check_and_wait_while_suspended() 3452 3453 slp->park(millis); 3454 3455 // were we externally suspended while we were waiting? 3456 this->check_and_wait_while_suspended(); 3457 } 3458 3459 // Update elapsed time tracking 3460 jlong newtime = os::javaTimeNanos(); 3461 if (newtime - prevtime < 0) { 3462 // time moving backwards, should only happen if no monotonic clock 3463 // not a guarantee() because JVM should not abort on kernel/glibc bugs 3464 assert(!os::supports_monotonic_clock(), 3465 "unexpected time moving backwards detected in JavaThread::sleep()"); 3466 } else { 3467 millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC; 3468 } 3469 prevtime = newtime; 3470 } 3471 } 3472 3473 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3474 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3475 CompileBroker::compiler_thread_loop(); 3476 } 3477 3478 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3479 NMethodSweeper::sweeper_loop(); 3480 } 3481 3482 // Create a CompilerThread 3483 CompilerThread::CompilerThread(CompileQueue* queue, 3484 CompilerCounters* counters) 3485 : JavaThread(&compiler_thread_entry) { 3486 _env = NULL; 3487 _log = NULL; 3488 _task = NULL; 3489 _queue = queue; 3490 _counters = counters; 3491 _buffer_blob = NULL; 3492 _compiler = NULL; 3493 3494 // Compiler uses resource area for compilation, let's bias it to mtCompiler 3495 resource_area()->bias_to(mtCompiler); 3496 3497 #ifndef PRODUCT 3498 _ideal_graph_printer = NULL; 3499 #endif 3500 } 3501 3502 CompilerThread::~CompilerThread() { 3503 // Delete objects which were allocated on heap. 3504 delete _counters; 3505 } 3506 3507 bool CompilerThread::can_call_java() const { 3508 return _compiler != NULL && _compiler->is_jvmci(); 3509 } 3510 3511 // Create sweeper thread 3512 CodeCacheSweeperThread::CodeCacheSweeperThread() 3513 : JavaThread(&sweeper_thread_entry) { 3514 _scanned_compiled_method = NULL; 3515 } 3516 3517 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 3518 JavaThread::oops_do(f, cf); 3519 if (_scanned_compiled_method != NULL && cf != NULL) { 3520 // Safepoints can occur when the sweeper is scanning an nmethod so 3521 // process it here to make sure it isn't unloaded in the middle of 3522 // a scan. 3523 cf->do_code_blob(_scanned_compiled_method); 3524 } 3525 } 3526 3527 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) { 3528 JavaThread::nmethods_do(cf); 3529 if (_scanned_compiled_method != NULL && cf != NULL) { 3530 // Safepoints can occur when the sweeper is scanning an nmethod so 3531 // process it here to make sure it isn't unloaded in the middle of 3532 // a scan. 3533 cf->do_code_blob(_scanned_compiled_method); 3534 } 3535 } 3536 3537 3538 // ======= Threads ======== 3539 3540 // The Threads class links together all active threads, and provides 3541 // operations over all threads. It is protected by the Threads_lock, 3542 // which is also used in other global contexts like safepointing. 3543 // ThreadsListHandles are used to safely perform operations on one 3544 // or more threads without the risk of the thread exiting during the 3545 // operation. 3546 // 3547 // Note: The Threads_lock is currently more widely used than we 3548 // would like. We are actively migrating Threads_lock uses to other 3549 // mechanisms in order to reduce Threads_lock contention. 3550 3551 int Threads::_number_of_threads = 0; 3552 int Threads::_number_of_non_daemon_threads = 0; 3553 int Threads::_return_code = 0; 3554 uintx Threads::_thread_claim_token = 1; // Never zero. 3555 size_t JavaThread::_stack_size_at_create = 0; 3556 3557 #ifdef ASSERT 3558 bool Threads::_vm_complete = false; 3559 #endif 3560 3561 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) { 3562 Prefetch::read((void*)addr, prefetch_interval); 3563 return *addr; 3564 } 3565 3566 // Possibly the ugliest for loop the world has seen. C++ does not allow 3567 // multiple types in the declaration section of the for loop. In this case 3568 // we are only dealing with pointers and hence can cast them. It looks ugly 3569 // but macros are ugly and therefore it's fine to make things absurdly ugly. 3570 #define DO_JAVA_THREADS(LIST, X) \ 3571 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \ 3572 *MACRO_list = (JavaThread*)(LIST), \ 3573 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \ 3574 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \ 3575 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \ 3576 MACRO_current_p != MACRO_end; \ 3577 MACRO_current_p++, \ 3578 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval)) 3579 3580 // All JavaThreads 3581 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X) 3582 3583 // All NonJavaThreads (i.e., every non-JavaThread in the system). 3584 void Threads::non_java_threads_do(ThreadClosure* tc) { 3585 NoSafepointVerifier nsv; 3586 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) { 3587 tc->do_thread(njti.current()); 3588 } 3589 } 3590 3591 // All JavaThreads 3592 void Threads::java_threads_do(ThreadClosure* tc) { 3593 assert_locked_or_safepoint(Threads_lock); 3594 // ALL_JAVA_THREADS iterates through all JavaThreads. 3595 ALL_JAVA_THREADS(p) { 3596 tc->do_thread(p); 3597 } 3598 } 3599 3600 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) { 3601 assert_locked_or_safepoint(Threads_lock); 3602 java_threads_do(tc); 3603 tc->do_thread(VMThread::vm_thread()); 3604 } 3605 3606 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system). 3607 void Threads::threads_do(ThreadClosure* tc) { 3608 assert_locked_or_safepoint(Threads_lock); 3609 java_threads_do(tc); 3610 non_java_threads_do(tc); 3611 } 3612 3613 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) { 3614 uintx claim_token = Threads::thread_claim_token(); 3615 ALL_JAVA_THREADS(p) { 3616 if (p->claim_threads_do(is_par, claim_token)) { 3617 tc->do_thread(p); 3618 } 3619 } 3620 VMThread* vmt = VMThread::vm_thread(); 3621 if (vmt->claim_threads_do(is_par, claim_token)) { 3622 tc->do_thread(vmt); 3623 } 3624 } 3625 3626 // The system initialization in the library has three phases. 3627 // 3628 // Phase 1: java.lang.System class initialization 3629 // java.lang.System is a primordial class loaded and initialized 3630 // by the VM early during startup. java.lang.System.<clinit> 3631 // only does registerNatives and keeps the rest of the class 3632 // initialization work later until thread initialization completes. 3633 // 3634 // System.initPhase1 initializes the system properties, the static 3635 // fields in, out, and err. Set up java signal handlers, OS-specific 3636 // system settings, and thread group of the main thread. 3637 static void call_initPhase1(TRAPS) { 3638 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3639 JavaValue result(T_VOID); 3640 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(), 3641 vmSymbols::void_method_signature(), CHECK); 3642 } 3643 3644 // Phase 2. Module system initialization 3645 // This will initialize the module system. Only java.base classes 3646 // can be loaded until phase 2 completes. 3647 // 3648 // Call System.initPhase2 after the compiler initialization and jsr292 3649 // classes get initialized because module initialization runs a lot of java 3650 // code, that for performance reasons, should be compiled. Also, this will 3651 // enable the startup code to use lambda and other language features in this 3652 // phase and onward. 3653 // 3654 // After phase 2, The VM will begin search classes from -Xbootclasspath/a. 3655 static void call_initPhase2(TRAPS) { 3656 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime)); 3657 3658 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3659 3660 JavaValue result(T_INT); 3661 JavaCallArguments args; 3662 args.push_int(DisplayVMOutputToStderr); 3663 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown 3664 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(), 3665 vmSymbols::boolean_boolean_int_signature(), &args, CHECK); 3666 if (result.get_jint() != JNI_OK) { 3667 vm_exit_during_initialization(); // no message or exception 3668 } 3669 3670 universe_post_module_init(); 3671 } 3672 3673 // Phase 3. final setup - set security manager, system class loader and TCCL 3674 // 3675 // This will instantiate and set the security manager, set the system class 3676 // loader as well as the thread context class loader. The security manager 3677 // and system class loader may be a custom class loaded from -Xbootclasspath/a, 3678 // other modules or the application's classpath. 3679 static void call_initPhase3(TRAPS) { 3680 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3681 JavaValue result(T_VOID); 3682 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(), 3683 vmSymbols::void_method_signature(), CHECK); 3684 } 3685 3686 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3687 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime)); 3688 3689 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3690 create_vm_init_libraries(); 3691 } 3692 3693 initialize_class(vmSymbols::java_lang_String(), CHECK); 3694 3695 // Inject CompactStrings value after the static initializers for String ran. 3696 java_lang_String::set_compact_strings(CompactStrings); 3697 3698 // Initialize java_lang.System (needed before creating the thread) 3699 initialize_class(vmSymbols::java_lang_System(), CHECK); 3700 // The VM creates & returns objects of this class. Make sure it's initialized. 3701 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3702 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3703 Handle thread_group = create_initial_thread_group(CHECK); 3704 Universe::set_main_thread_group(thread_group()); 3705 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3706 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3707 main_thread->set_threadObj(thread_object); 3708 3709 // Set thread status to running since main thread has 3710 // been started and running. 3711 java_lang_Thread::set_thread_status(thread_object, 3712 java_lang_Thread::RUNNABLE); 3713 3714 // The VM creates objects of this class. 3715 initialize_class(vmSymbols::java_lang_Module(), CHECK); 3716 3717 #ifdef ASSERT 3718 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass(); 3719 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized"); 3720 #endif 3721 3722 // initialize the hardware-specific constants needed by Unsafe 3723 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK); 3724 jdk_internal_misc_UnsafeConstants::set_unsafe_constants(); 3725 3726 // The VM preresolves methods to these classes. Make sure that they get initialized 3727 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3728 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3729 3730 // Phase 1 of the system initialization in the library, java.lang.System class initialization 3731 call_initPhase1(CHECK); 3732 3733 // get the Java runtime name, version, and vendor info after java.lang.System is initialized 3734 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3735 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3736 JDK_Version::set_runtime_vendor_version(get_java_runtime_vendor_version(THREAD)); 3737 JDK_Version::set_runtime_vendor_vm_bug_url(get_java_runtime_vendor_vm_bug_url(THREAD)); 3738 3739 // an instance of OutOfMemory exception has been allocated earlier 3740 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3741 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3742 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3743 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3744 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3745 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3746 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3747 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3748 3749 // Eager box cache initialization only if AOT is on and any library is loaded. 3750 AOTLoader::initialize_box_caches(CHECK); 3751 } 3752 3753 void Threads::initialize_jsr292_core_classes(TRAPS) { 3754 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime)); 3755 3756 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3757 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK); 3758 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3759 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3760 } 3761 3762 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3763 extern void JDK_Version_init(); 3764 3765 // Preinitialize version info. 3766 VM_Version::early_initialize(); 3767 3768 // Check version 3769 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3770 3771 // Initialize library-based TLS 3772 ThreadLocalStorage::init(); 3773 3774 // Initialize the output stream module 3775 ostream_init(); 3776 3777 // Process java launcher properties. 3778 Arguments::process_sun_java_launcher_properties(args); 3779 3780 // Initialize the os module 3781 os::init(); 3782 3783 // Record VM creation timing statistics 3784 TraceVmCreationTime create_vm_timer; 3785 create_vm_timer.start(); 3786 3787 // Initialize system properties. 3788 Arguments::init_system_properties(); 3789 3790 // So that JDK version can be used as a discriminator when parsing arguments 3791 JDK_Version_init(); 3792 3793 // Update/Initialize System properties after JDK version number is known 3794 Arguments::init_version_specific_system_properties(); 3795 3796 // Make sure to initialize log configuration *before* parsing arguments 3797 LogConfiguration::initialize(create_vm_timer.begin_time()); 3798 3799 // Parse arguments 3800 // Note: this internally calls os::init_container_support() 3801 jint parse_result = Arguments::parse(args); 3802 if (parse_result != JNI_OK) return parse_result; 3803 3804 os::init_before_ergo(); 3805 3806 jint ergo_result = Arguments::apply_ergo(); 3807 if (ergo_result != JNI_OK) return ergo_result; 3808 3809 // Final check of all ranges after ergonomics which may change values. 3810 if (!JVMFlagRangeList::check_ranges()) { 3811 return JNI_EINVAL; 3812 } 3813 3814 // Final check of all 'AfterErgo' constraints after ergonomics which may change values. 3815 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo); 3816 if (!constraint_result) { 3817 return JNI_EINVAL; 3818 } 3819 3820 if (PauseAtStartup) { 3821 os::pause(); 3822 } 3823 3824 HOTSPOT_VM_INIT_BEGIN(); 3825 3826 // Timing (must come after argument parsing) 3827 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime)); 3828 3829 // Initialize the os module after parsing the args 3830 jint os_init_2_result = os::init_2(); 3831 if (os_init_2_result != JNI_OK) return os_init_2_result; 3832 3833 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT 3834 // Initialize assert poison page mechanism. 3835 if (ShowRegistersOnAssert) { 3836 initialize_assert_poison(); 3837 } 3838 #endif // CAN_SHOW_REGISTERS_ON_ASSERT 3839 3840 SafepointMechanism::initialize(); 3841 3842 jint adjust_after_os_result = Arguments::adjust_after_os(); 3843 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3844 3845 // Initialize output stream logging 3846 ostream_init_log(); 3847 3848 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3849 // Must be before create_vm_init_agents() 3850 if (Arguments::init_libraries_at_startup()) { 3851 convert_vm_init_libraries_to_agents(); 3852 } 3853 3854 // Launch -agentlib/-agentpath and converted -Xrun agents 3855 if (Arguments::init_agents_at_startup()) { 3856 create_vm_init_agents(); 3857 } 3858 3859 // Initialize Threads state 3860 _number_of_threads = 0; 3861 _number_of_non_daemon_threads = 0; 3862 3863 // Initialize global data structures and create system classes in heap 3864 vm_init_globals(); 3865 3866 #if INCLUDE_JVMCI 3867 if (JVMCICounterSize > 0) { 3868 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI); 3869 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize); 3870 } else { 3871 JavaThread::_jvmci_old_thread_counters = NULL; 3872 } 3873 #endif // INCLUDE_JVMCI 3874 3875 // Attach the main thread to this os thread 3876 JavaThread* main_thread = new JavaThread(); 3877 main_thread->set_thread_state(_thread_in_vm); 3878 main_thread->initialize_thread_current(); 3879 // must do this before set_active_handles 3880 main_thread->record_stack_base_and_size(); 3881 main_thread->register_thread_stack_with_NMT(); 3882 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3883 3884 if (!main_thread->set_as_starting_thread()) { 3885 vm_shutdown_during_initialization( 3886 "Failed necessary internal allocation. Out of swap space"); 3887 main_thread->smr_delete(); 3888 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3889 return JNI_ENOMEM; 3890 } 3891 3892 // Enable guard page *after* os::create_main_thread(), otherwise it would 3893 // crash Linux VM, see notes in os_linux.cpp. 3894 main_thread->create_stack_guard_pages(); 3895 3896 // Initialize Java-Level synchronization subsystem 3897 ObjectMonitor::Initialize(); 3898 3899 // Initialize global modules 3900 jint status = init_globals(); 3901 if (status != JNI_OK) { 3902 main_thread->smr_delete(); 3903 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3904 return status; 3905 } 3906 3907 JFR_ONLY(Jfr::on_create_vm_1();) 3908 3909 // Should be done after the heap is fully created 3910 main_thread->cache_global_variables(); 3911 3912 HandleMark hm; 3913 3914 { MutexLocker mu(Threads_lock); 3915 Threads::add(main_thread); 3916 } 3917 3918 // Any JVMTI raw monitors entered in onload will transition into 3919 // real raw monitor. VM is setup enough here for raw monitor enter. 3920 JvmtiExport::transition_pending_onload_raw_monitors(); 3921 3922 // Create the VMThread 3923 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime)); 3924 3925 VMThread::create(); 3926 Thread* vmthread = VMThread::vm_thread(); 3927 3928 if (!os::create_thread(vmthread, os::vm_thread)) { 3929 vm_exit_during_initialization("Cannot create VM thread. " 3930 "Out of system resources."); 3931 } 3932 3933 // Wait for the VM thread to become ready, and VMThread::run to initialize 3934 // Monitors can have spurious returns, must always check another state flag 3935 { 3936 MonitorLocker ml(Notify_lock); 3937 os::start_thread(vmthread); 3938 while (vmthread->active_handles() == NULL) { 3939 ml.wait(); 3940 } 3941 } 3942 } 3943 3944 assert(Universe::is_fully_initialized(), "not initialized"); 3945 if (VerifyDuringStartup) { 3946 // Make sure we're starting with a clean slate. 3947 VM_Verify verify_op; 3948 VMThread::execute(&verify_op); 3949 } 3950 3951 // We need this to update the java.vm.info property in case any flags used 3952 // to initially define it have been changed. This is needed for both CDS and 3953 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info 3954 // is initially computed. See Abstract_VM_Version::vm_info_string(). 3955 // This update must happen before we initialize the java classes, but 3956 // after any initialization logic that might modify the flags. 3957 Arguments::update_vm_info_property(VM_Version::vm_info_string()); 3958 3959 Thread* THREAD = Thread::current(); 3960 3961 // Always call even when there are not JVMTI environments yet, since environments 3962 // may be attached late and JVMTI must track phases of VM execution 3963 JvmtiExport::enter_early_start_phase(); 3964 3965 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3966 JvmtiExport::post_early_vm_start(); 3967 3968 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3969 3970 quicken_jni_functions(); 3971 3972 // No more stub generation allowed after that point. 3973 StubCodeDesc::freeze(); 3974 3975 // Set flag that basic initialization has completed. Used by exceptions and various 3976 // debug stuff, that does not work until all basic classes have been initialized. 3977 set_init_completed(); 3978 3979 LogConfiguration::post_initialize(); 3980 Metaspace::post_initialize(); 3981 3982 HOTSPOT_VM_INIT_END(); 3983 3984 // record VM initialization completion time 3985 #if INCLUDE_MANAGEMENT 3986 Management::record_vm_init_completed(); 3987 #endif // INCLUDE_MANAGEMENT 3988 3989 // Signal Dispatcher needs to be started before VMInit event is posted 3990 os::initialize_jdk_signal_support(CHECK_JNI_ERR); 3991 3992 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3993 if (!DisableAttachMechanism) { 3994 AttachListener::vm_start(); 3995 if (StartAttachListener || AttachListener::init_at_startup()) { 3996 AttachListener::init(); 3997 } 3998 } 3999 4000 // Launch -Xrun agents 4001 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 4002 // back-end can launch with -Xdebug -Xrunjdwp. 4003 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 4004 create_vm_init_libraries(); 4005 } 4006 4007 if (CleanChunkPoolAsync) { 4008 Chunk::start_chunk_pool_cleaner_task(); 4009 } 4010 4011 // Start the service thread 4012 // The service thread enqueues JVMTI deferred events and does various hashtable 4013 // and other cleanups. Needs to start before the compilers start posting events. 4014 ServiceThread::initialize(); 4015 4016 // initialize compiler(s) 4017 #if defined(COMPILER1) || COMPILER2_OR_JVMCI 4018 #if INCLUDE_JVMCI 4019 bool force_JVMCI_intialization = false; 4020 if (EnableJVMCI) { 4021 // Initialize JVMCI eagerly when it is explicitly requested. 4022 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled. 4023 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig; 4024 4025 if (!force_JVMCI_intialization) { 4026 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking 4027 // compilations via JVMCI will not actually block until JVMCI is initialized. 4028 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation); 4029 } 4030 } 4031 #endif 4032 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR); 4033 // Postpone completion of compiler initialization to after JVMCI 4034 // is initialized to avoid timeouts of blocking compilations. 4035 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) { 4036 CompileBroker::compilation_init_phase2(); 4037 } 4038 #endif 4039 4040 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 4041 // It is done after compilers are initialized, because otherwise compilations of 4042 // signature polymorphic MH intrinsics can be missed 4043 // (see SystemDictionary::find_method_handle_intrinsic). 4044 initialize_jsr292_core_classes(CHECK_JNI_ERR); 4045 4046 // This will initialize the module system. Only java.base classes can be 4047 // loaded until phase 2 completes 4048 call_initPhase2(CHECK_JNI_ERR); 4049 4050 JFR_ONLY(Jfr::on_create_vm_2();) 4051 4052 // Always call even when there are not JVMTI environments yet, since environments 4053 // may be attached late and JVMTI must track phases of VM execution 4054 JvmtiExport::enter_start_phase(); 4055 4056 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 4057 JvmtiExport::post_vm_start(); 4058 4059 // Final system initialization including security manager and system class loader 4060 call_initPhase3(CHECK_JNI_ERR); 4061 4062 // cache the system and platform class loaders 4063 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR); 4064 4065 #if INCLUDE_CDS 4066 // capture the module path info from the ModuleEntryTable 4067 ClassLoader::initialize_module_path(THREAD); 4068 #endif 4069 4070 #if INCLUDE_JVMCI 4071 if (force_JVMCI_intialization) { 4072 JVMCI::initialize_compiler(CHECK_JNI_ERR); 4073 CompileBroker::compilation_init_phase2(); 4074 } 4075 #endif 4076 4077 // Always call even when there are not JVMTI environments yet, since environments 4078 // may be attached late and JVMTI must track phases of VM execution 4079 JvmtiExport::enter_live_phase(); 4080 4081 // Make perfmemory accessible 4082 PerfMemory::set_accessible(true); 4083 4084 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 4085 JvmtiExport::post_vm_initialized(); 4086 4087 JFR_ONLY(Jfr::on_create_vm_3();) 4088 4089 #if INCLUDE_MANAGEMENT 4090 Management::initialize(THREAD); 4091 4092 if (HAS_PENDING_EXCEPTION) { 4093 // management agent fails to start possibly due to 4094 // configuration problem and is responsible for printing 4095 // stack trace if appropriate. Simply exit VM. 4096 vm_exit(1); 4097 } 4098 #endif // INCLUDE_MANAGEMENT 4099 4100 if (MemProfiling) MemProfiler::engage(); 4101 StatSampler::engage(); 4102 if (CheckJNICalls) JniPeriodicChecker::engage(); 4103 4104 BiasedLocking::init(); 4105 4106 #if INCLUDE_RTM_OPT 4107 RTMLockingCounters::init(); 4108 #endif 4109 4110 call_postVMInitHook(THREAD); 4111 // The Java side of PostVMInitHook.run must deal with all 4112 // exceptions and provide means of diagnosis. 4113 if (HAS_PENDING_EXCEPTION) { 4114 CLEAR_PENDING_EXCEPTION; 4115 } 4116 4117 { 4118 MutexLocker ml(PeriodicTask_lock); 4119 // Make sure the WatcherThread can be started by WatcherThread::start() 4120 // or by dynamic enrollment. 4121 WatcherThread::make_startable(); 4122 // Start up the WatcherThread if there are any periodic tasks 4123 // NOTE: All PeriodicTasks should be registered by now. If they 4124 // aren't, late joiners might appear to start slowly (we might 4125 // take a while to process their first tick). 4126 if (PeriodicTask::num_tasks() > 0) { 4127 WatcherThread::start(); 4128 } 4129 } 4130 4131 create_vm_timer.end(); 4132 #ifdef ASSERT 4133 _vm_complete = true; 4134 #endif 4135 4136 if (DumpSharedSpaces) { 4137 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 4138 ShouldNotReachHere(); 4139 } 4140 4141 return JNI_OK; 4142 } 4143 4144 // type for the Agent_OnLoad and JVM_OnLoad entry points 4145 extern "C" { 4146 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 4147 } 4148 // Find a command line agent library and return its entry point for 4149 // -agentlib: -agentpath: -Xrun 4150 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 4151 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 4152 const char *on_load_symbols[], 4153 size_t num_symbol_entries) { 4154 OnLoadEntry_t on_load_entry = NULL; 4155 void *library = NULL; 4156 4157 if (!agent->valid()) { 4158 char buffer[JVM_MAXPATHLEN]; 4159 char ebuf[1024] = ""; 4160 const char *name = agent->name(); 4161 const char *msg = "Could not find agent library "; 4162 4163 // First check to see if agent is statically linked into executable 4164 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 4165 library = agent->os_lib(); 4166 } else if (agent->is_absolute_path()) { 4167 library = os::dll_load(name, ebuf, sizeof ebuf); 4168 if (library == NULL) { 4169 const char *sub_msg = " in absolute path, with error: "; 4170 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 4171 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 4172 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 4173 // If we can't find the agent, exit. 4174 vm_exit_during_initialization(buf, NULL); 4175 FREE_C_HEAP_ARRAY(char, buf); 4176 } 4177 } else { 4178 // Try to load the agent from the standard dll directory 4179 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(), 4180 name)) { 4181 library = os::dll_load(buffer, ebuf, sizeof ebuf); 4182 } 4183 if (library == NULL) { // Try the library path directory. 4184 if (os::dll_build_name(buffer, sizeof(buffer), name)) { 4185 library = os::dll_load(buffer, ebuf, sizeof ebuf); 4186 } 4187 if (library == NULL) { 4188 const char *sub_msg = " on the library path, with error: "; 4189 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image."; 4190 4191 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + 4192 strlen(ebuf) + strlen(sub_msg2) + 1; 4193 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 4194 if (!agent->is_instrument_lib()) { 4195 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 4196 } else { 4197 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2); 4198 } 4199 // If we can't find the agent, exit. 4200 vm_exit_during_initialization(buf, NULL); 4201 FREE_C_HEAP_ARRAY(char, buf); 4202 } 4203 } 4204 } 4205 agent->set_os_lib(library); 4206 agent->set_valid(); 4207 } 4208 4209 // Find the OnLoad function. 4210 on_load_entry = 4211 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 4212 false, 4213 on_load_symbols, 4214 num_symbol_entries)); 4215 return on_load_entry; 4216 } 4217 4218 // Find the JVM_OnLoad entry point 4219 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 4220 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 4221 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 4222 } 4223 4224 // Find the Agent_OnLoad entry point 4225 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 4226 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 4227 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 4228 } 4229 4230 // For backwards compatibility with -Xrun 4231 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 4232 // treated like -agentpath: 4233 // Must be called before agent libraries are created 4234 void Threads::convert_vm_init_libraries_to_agents() { 4235 AgentLibrary* agent; 4236 AgentLibrary* next; 4237 4238 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 4239 next = agent->next(); // cache the next agent now as this agent may get moved off this list 4240 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 4241 4242 // If there is an JVM_OnLoad function it will get called later, 4243 // otherwise see if there is an Agent_OnLoad 4244 if (on_load_entry == NULL) { 4245 on_load_entry = lookup_agent_on_load(agent); 4246 if (on_load_entry != NULL) { 4247 // switch it to the agent list -- so that Agent_OnLoad will be called, 4248 // JVM_OnLoad won't be attempted and Agent_OnUnload will 4249 Arguments::convert_library_to_agent(agent); 4250 } else { 4251 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 4252 } 4253 } 4254 } 4255 } 4256 4257 // Create agents for -agentlib: -agentpath: and converted -Xrun 4258 // Invokes Agent_OnLoad 4259 // Called very early -- before JavaThreads exist 4260 void Threads::create_vm_init_agents() { 4261 extern struct JavaVM_ main_vm; 4262 AgentLibrary* agent; 4263 4264 JvmtiExport::enter_onload_phase(); 4265 4266 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 4267 // CDS dumping does not support native JVMTI agent. 4268 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified. 4269 if (Arguments::is_dumping_archive()) { 4270 if(!agent->is_instrument_lib()) { 4271 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name()); 4272 } else if (!AllowArchivingWithJavaAgent) { 4273 vm_exit_during_cds_dumping( 4274 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping"); 4275 } 4276 } 4277 4278 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 4279 4280 if (on_load_entry != NULL) { 4281 // Invoke the Agent_OnLoad function 4282 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 4283 if (err != JNI_OK) { 4284 vm_exit_during_initialization("agent library failed to init", agent->name()); 4285 } 4286 } else { 4287 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 4288 } 4289 } 4290 4291 JvmtiExport::enter_primordial_phase(); 4292 } 4293 4294 extern "C" { 4295 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 4296 } 4297 4298 void Threads::shutdown_vm_agents() { 4299 // Send any Agent_OnUnload notifications 4300 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 4301 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 4302 extern struct JavaVM_ main_vm; 4303 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 4304 4305 // Find the Agent_OnUnload function. 4306 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 4307 os::find_agent_function(agent, 4308 false, 4309 on_unload_symbols, 4310 num_symbol_entries)); 4311 4312 // Invoke the Agent_OnUnload function 4313 if (unload_entry != NULL) { 4314 JavaThread* thread = JavaThread::current(); 4315 ThreadToNativeFromVM ttn(thread); 4316 HandleMark hm(thread); 4317 (*unload_entry)(&main_vm); 4318 } 4319 } 4320 } 4321 4322 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 4323 // Invokes JVM_OnLoad 4324 void Threads::create_vm_init_libraries() { 4325 extern struct JavaVM_ main_vm; 4326 AgentLibrary* agent; 4327 4328 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 4329 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 4330 4331 if (on_load_entry != NULL) { 4332 // Invoke the JVM_OnLoad function 4333 JavaThread* thread = JavaThread::current(); 4334 ThreadToNativeFromVM ttn(thread); 4335 HandleMark hm(thread); 4336 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 4337 if (err != JNI_OK) { 4338 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 4339 } 4340 } else { 4341 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 4342 } 4343 } 4344 } 4345 4346 4347 // Last thread running calls java.lang.Shutdown.shutdown() 4348 void JavaThread::invoke_shutdown_hooks() { 4349 HandleMark hm(this); 4350 4351 // We could get here with a pending exception, if so clear it now. 4352 if (this->has_pending_exception()) { 4353 this->clear_pending_exception(); 4354 } 4355 4356 EXCEPTION_MARK; 4357 Klass* shutdown_klass = 4358 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 4359 THREAD); 4360 if (shutdown_klass != NULL) { 4361 // SystemDictionary::resolve_or_null will return null if there was 4362 // an exception. If we cannot load the Shutdown class, just don't 4363 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 4364 // won't be run. Note that if a shutdown hook was registered, 4365 // the Shutdown class would have already been loaded 4366 // (Runtime.addShutdownHook will load it). 4367 JavaValue result(T_VOID); 4368 JavaCalls::call_static(&result, 4369 shutdown_klass, 4370 vmSymbols::shutdown_name(), 4371 vmSymbols::void_method_signature(), 4372 THREAD); 4373 } 4374 CLEAR_PENDING_EXCEPTION; 4375 } 4376 4377 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 4378 // the program falls off the end of main(). Another VM exit path is through 4379 // vm_exit() when the program calls System.exit() to return a value or when 4380 // there is a serious error in VM. The two shutdown paths are not exactly 4381 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 4382 // and VM_Exit op at VM level. 4383 // 4384 // Shutdown sequence: 4385 // + Shutdown native memory tracking if it is on 4386 // + Wait until we are the last non-daemon thread to execute 4387 // <-- every thing is still working at this moment --> 4388 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 4389 // shutdown hooks 4390 // + Call before_exit(), prepare for VM exit 4391 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 4392 // currently the only user of this mechanism is File.deleteOnExit()) 4393 // > stop StatSampler, watcher thread, 4394 // post thread end and vm death events to JVMTI, 4395 // stop signal thread 4396 // + Call JavaThread::exit(), it will: 4397 // > release JNI handle blocks, remove stack guard pages 4398 // > remove this thread from Threads list 4399 // <-- no more Java code from this thread after this point --> 4400 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 4401 // the compiler threads at safepoint 4402 // <-- do not use anything that could get blocked by Safepoint --> 4403 // + Disable tracing at JNI/JVM barriers 4404 // + Set _vm_exited flag for threads that are still running native code 4405 // + Call exit_globals() 4406 // > deletes tty 4407 // > deletes PerfMemory resources 4408 // + Delete this thread 4409 // + Return to caller 4410 4411 bool Threads::destroy_vm() { 4412 JavaThread* thread = JavaThread::current(); 4413 4414 #ifdef ASSERT 4415 _vm_complete = false; 4416 #endif 4417 // Wait until we are the last non-daemon thread to execute 4418 { MonitorLocker nu(Threads_lock); 4419 while (Threads::number_of_non_daemon_threads() > 1) 4420 // This wait should make safepoint checks, wait without a timeout, 4421 // and wait as a suspend-equivalent condition. 4422 nu.wait(0, Mutex::_as_suspend_equivalent_flag); 4423 } 4424 4425 EventShutdown e; 4426 if (e.should_commit()) { 4427 e.set_reason("No remaining non-daemon Java threads"); 4428 e.commit(); 4429 } 4430 4431 // Hang forever on exit if we are reporting an error. 4432 if (ShowMessageBoxOnError && VMError::is_error_reported()) { 4433 os::infinite_sleep(); 4434 } 4435 os::wait_for_keypress_at_exit(); 4436 4437 // run Java level shutdown hooks 4438 thread->invoke_shutdown_hooks(); 4439 4440 before_exit(thread); 4441 4442 thread->exit(true); 4443 4444 // Stop VM thread. 4445 { 4446 // 4945125 The vm thread comes to a safepoint during exit. 4447 // GC vm_operations can get caught at the safepoint, and the 4448 // heap is unparseable if they are caught. Grab the Heap_lock 4449 // to prevent this. The GC vm_operations will not be able to 4450 // queue until after the vm thread is dead. After this point, 4451 // we'll never emerge out of the safepoint before the VM exits. 4452 4453 MutexLocker ml(Heap_lock, Mutex::_no_safepoint_check_flag); 4454 4455 VMThread::wait_for_vm_thread_exit(); 4456 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4457 VMThread::destroy(); 4458 } 4459 4460 // Now, all Java threads are gone except daemon threads. Daemon threads 4461 // running Java code or in VM are stopped by the Safepoint. However, 4462 // daemon threads executing native code are still running. But they 4463 // will be stopped at native=>Java/VM barriers. Note that we can't 4464 // simply kill or suspend them, as it is inherently deadlock-prone. 4465 4466 VM_Exit::set_vm_exited(); 4467 4468 // Clean up ideal graph printers after the VMThread has started 4469 // the final safepoint which will block all the Compiler threads. 4470 // Note that this Thread has already logically exited so the 4471 // clean_up() function's use of a JavaThreadIteratorWithHandle 4472 // would be a problem except set_vm_exited() has remembered the 4473 // shutdown thread which is granted a policy exception. 4474 #if defined(COMPILER2) && !defined(PRODUCT) 4475 IdealGraphPrinter::clean_up(); 4476 #endif 4477 4478 notify_vm_shutdown(); 4479 4480 // exit_globals() will delete tty 4481 exit_globals(); 4482 4483 // We are after VM_Exit::set_vm_exited() so we can't call 4484 // thread->smr_delete() or we will block on the Threads_lock. 4485 // Deleting the shutdown thread here is safe because another 4486 // JavaThread cannot have an active ThreadsListHandle for 4487 // this JavaThread. 4488 delete thread; 4489 4490 #if INCLUDE_JVMCI 4491 if (JVMCICounterSize > 0) { 4492 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters); 4493 } 4494 #endif 4495 4496 LogConfiguration::finalize(); 4497 4498 return true; 4499 } 4500 4501 4502 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4503 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4504 return is_supported_jni_version(version); 4505 } 4506 4507 4508 jboolean Threads::is_supported_jni_version(jint version) { 4509 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4510 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4511 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4512 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4513 if (version == JNI_VERSION_9) return JNI_TRUE; 4514 if (version == JNI_VERSION_10) return JNI_TRUE; 4515 return JNI_FALSE; 4516 } 4517 4518 4519 void Threads::add(JavaThread* p, bool force_daemon) { 4520 // The threads lock must be owned at this point 4521 assert(Threads_lock->owned_by_self(), "must have threads lock"); 4522 4523 BarrierSet::barrier_set()->on_thread_attach(p); 4524 4525 // Once a JavaThread is added to the Threads list, smr_delete() has 4526 // to be used to delete it. Otherwise we can just delete it directly. 4527 p->set_on_thread_list(); 4528 4529 _number_of_threads++; 4530 oop threadObj = p->threadObj(); 4531 bool daemon = true; 4532 // Bootstrapping problem: threadObj can be null for initial 4533 // JavaThread (or for threads attached via JNI) 4534 if ((!force_daemon) && !is_daemon((threadObj))) { 4535 _number_of_non_daemon_threads++; 4536 daemon = false; 4537 } 4538 4539 ThreadService::add_thread(p, daemon); 4540 4541 // Maintain fast thread list 4542 ThreadsSMRSupport::add_thread(p); 4543 4544 // Possible GC point. 4545 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p)); 4546 } 4547 4548 void Threads::remove(JavaThread* p, bool is_daemon) { 4549 4550 // Reclaim the ObjectMonitors from the om_in_use_list and om_free_list of the moribund thread. 4551 ObjectSynchronizer::om_flush(p); 4552 4553 // Extra scope needed for Thread_lock, so we can check 4554 // that we do not remove thread without safepoint code notice 4555 { MonitorLocker ml(Threads_lock); 4556 4557 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present"); 4558 4559 // Maintain fast thread list 4560 ThreadsSMRSupport::remove_thread(p); 4561 4562 _number_of_threads--; 4563 if (!is_daemon) { 4564 _number_of_non_daemon_threads--; 4565 4566 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4567 // on destroy_vm will wake up. 4568 if (number_of_non_daemon_threads() == 1) { 4569 ml.notify_all(); 4570 } 4571 } 4572 ThreadService::remove_thread(p, is_daemon); 4573 4574 // Make sure that safepoint code disregard this thread. This is needed since 4575 // the thread might mess around with locks after this point. This can cause it 4576 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4577 // of this thread since it is removed from the queue. 4578 p->set_terminated_value(); 4579 } // unlock Threads_lock 4580 4581 // Since Events::log uses a lock, we grab it outside the Threads_lock 4582 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p)); 4583 } 4584 4585 // Operations on the Threads list for GC. These are not explicitly locked, 4586 // but the garbage collector must provide a safe context for them to run. 4587 // In particular, these things should never be called when the Threads_lock 4588 // is held by some other thread. (Note: the Safepoint abstraction also 4589 // uses the Threads_lock to guarantee this property. It also makes sure that 4590 // all threads gets blocked when exiting or starting). 4591 4592 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) { 4593 ALL_JAVA_THREADS(p) { 4594 p->oops_do(f, cf); 4595 } 4596 VMThread::vm_thread()->oops_do(f, cf); 4597 } 4598 4599 void Threads::change_thread_claim_token() { 4600 if (++_thread_claim_token == 0) { 4601 // On overflow of the token counter, there is a risk of future 4602 // collisions between a new global token value and a stale token 4603 // for a thread, because not all iterations visit all threads. 4604 // (Though it's pretty much a theoretical concern for non-trivial 4605 // token counter sizes.) To deal with the possibility, reset all 4606 // the thread tokens to zero on global token overflow. 4607 struct ResetClaims : public ThreadClosure { 4608 virtual void do_thread(Thread* t) { 4609 t->claim_threads_do(false, 0); 4610 } 4611 } reset_claims; 4612 Threads::threads_do(&reset_claims); 4613 // On overflow, update the global token to non-zero, to 4614 // avoid the special "never claimed" initial thread value. 4615 _thread_claim_token = 1; 4616 } 4617 } 4618 4619 #ifdef ASSERT 4620 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) { 4621 const uintx token = t->threads_do_token(); 4622 assert(token == expected, 4623 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != " 4624 UINTX_FORMAT, kind, p2i(t), token, expected); 4625 } 4626 4627 void Threads::assert_all_threads_claimed() { 4628 ALL_JAVA_THREADS(p) { 4629 assert_thread_claimed("Thread", p, _thread_claim_token); 4630 } 4631 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token); 4632 } 4633 #endif // ASSERT 4634 4635 class ParallelOopsDoThreadClosure : public ThreadClosure { 4636 private: 4637 OopClosure* _f; 4638 CodeBlobClosure* _cf; 4639 public: 4640 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {} 4641 void do_thread(Thread* t) { 4642 t->oops_do(_f, _cf); 4643 } 4644 }; 4645 4646 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) { 4647 ParallelOopsDoThreadClosure tc(f, cf); 4648 possibly_parallel_threads_do(is_par, &tc); 4649 } 4650 4651 void Threads::nmethods_do(CodeBlobClosure* cf) { 4652 ALL_JAVA_THREADS(p) { 4653 // This is used by the code cache sweeper to mark nmethods that are active 4654 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid 4655 // marking CodeCacheSweeperThread::_scanned_compiled_method as active. 4656 if(!p->is_Code_cache_sweeper_thread()) { 4657 p->nmethods_do(cf); 4658 } 4659 } 4660 } 4661 4662 void Threads::metadata_do(MetadataClosure* f) { 4663 ALL_JAVA_THREADS(p) { 4664 p->metadata_do(f); 4665 } 4666 } 4667 4668 class ThreadHandlesClosure : public ThreadClosure { 4669 void (*_f)(Metadata*); 4670 public: 4671 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4672 virtual void do_thread(Thread* thread) { 4673 thread->metadata_handles_do(_f); 4674 } 4675 }; 4676 4677 void Threads::metadata_handles_do(void f(Metadata*)) { 4678 // Only walk the Handles in Thread. 4679 ThreadHandlesClosure handles_closure(f); 4680 threads_do(&handles_closure); 4681 } 4682 4683 // Get count Java threads that are waiting to enter the specified monitor. 4684 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list, 4685 int count, 4686 address monitor) { 4687 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4688 4689 int i = 0; 4690 DO_JAVA_THREADS(t_list, p) { 4691 if (!p->can_call_java()) continue; 4692 4693 address pending = (address)p->current_pending_monitor(); 4694 if (pending == monitor) { // found a match 4695 if (i < count) result->append(p); // save the first count matches 4696 i++; 4697 } 4698 } 4699 4700 return result; 4701 } 4702 4703 4704 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list, 4705 address owner) { 4706 // NULL owner means not locked so we can skip the search 4707 if (owner == NULL) return NULL; 4708 4709 DO_JAVA_THREADS(t_list, p) { 4710 // first, see if owner is the address of a Java thread 4711 if (owner == (address)p) return p; 4712 } 4713 4714 // Cannot assert on lack of success here since this function may be 4715 // used by code that is trying to report useful problem information 4716 // like deadlock detection. 4717 if (UseHeavyMonitors) return NULL; 4718 4719 // If we didn't find a matching Java thread and we didn't force use of 4720 // heavyweight monitors, then the owner is the stack address of the 4721 // Lock Word in the owning Java thread's stack. 4722 // 4723 JavaThread* the_owner = NULL; 4724 DO_JAVA_THREADS(t_list, q) { 4725 if (q->is_lock_owned(owner)) { 4726 the_owner = q; 4727 break; 4728 } 4729 } 4730 4731 // cannot assert on lack of success here; see above comment 4732 return the_owner; 4733 } 4734 4735 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4736 void Threads::print_on(outputStream* st, bool print_stacks, 4737 bool internal_format, bool print_concurrent_locks, 4738 bool print_extended_info) { 4739 char buf[32]; 4740 st->print_raw_cr(os::local_time_string(buf, sizeof(buf))); 4741 4742 st->print_cr("Full thread dump %s (%s %s):", 4743 VM_Version::vm_name(), 4744 VM_Version::vm_release(), 4745 VM_Version::vm_info_string()); 4746 st->cr(); 4747 4748 #if INCLUDE_SERVICES 4749 // Dump concurrent locks 4750 ConcurrentLocksDump concurrent_locks; 4751 if (print_concurrent_locks) { 4752 concurrent_locks.dump_at_safepoint(); 4753 } 4754 #endif // INCLUDE_SERVICES 4755 4756 ThreadsSMRSupport::print_info_on(st); 4757 st->cr(); 4758 4759 ALL_JAVA_THREADS(p) { 4760 ResourceMark rm; 4761 p->print_on(st, print_extended_info); 4762 if (print_stacks) { 4763 if (internal_format) { 4764 p->trace_stack(); 4765 } else { 4766 p->print_stack_on(st); 4767 } 4768 } 4769 st->cr(); 4770 #if INCLUDE_SERVICES 4771 if (print_concurrent_locks) { 4772 concurrent_locks.print_locks_on(p, st); 4773 } 4774 #endif // INCLUDE_SERVICES 4775 } 4776 4777 VMThread::vm_thread()->print_on(st); 4778 st->cr(); 4779 Universe::heap()->print_gc_threads_on(st); 4780 WatcherThread* wt = WatcherThread::watcher_thread(); 4781 if (wt != NULL) { 4782 wt->print_on(st); 4783 st->cr(); 4784 } 4785 4786 st->flush(); 4787 } 4788 4789 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf, 4790 int buflen, bool* found_current) { 4791 if (this_thread != NULL) { 4792 bool is_current = (current == this_thread); 4793 *found_current = *found_current || is_current; 4794 st->print("%s", is_current ? "=>" : " "); 4795 4796 st->print(PTR_FORMAT, p2i(this_thread)); 4797 st->print(" "); 4798 this_thread->print_on_error(st, buf, buflen); 4799 st->cr(); 4800 } 4801 } 4802 4803 class PrintOnErrorClosure : public ThreadClosure { 4804 outputStream* _st; 4805 Thread* _current; 4806 char* _buf; 4807 int _buflen; 4808 bool* _found_current; 4809 public: 4810 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf, 4811 int buflen, bool* found_current) : 4812 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {} 4813 4814 virtual void do_thread(Thread* thread) { 4815 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current); 4816 } 4817 }; 4818 4819 // Threads::print_on_error() is called by fatal error handler. It's possible 4820 // that VM is not at safepoint and/or current thread is inside signal handler. 4821 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4822 // memory (even in resource area), it might deadlock the error handler. 4823 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4824 int buflen) { 4825 ThreadsSMRSupport::print_info_on(st); 4826 st->cr(); 4827 4828 bool found_current = false; 4829 st->print_cr("Java Threads: ( => current thread )"); 4830 ALL_JAVA_THREADS(thread) { 4831 print_on_error(thread, st, current, buf, buflen, &found_current); 4832 } 4833 st->cr(); 4834 4835 st->print_cr("Other Threads:"); 4836 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current); 4837 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current); 4838 4839 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current); 4840 Universe::heap()->gc_threads_do(&print_closure); 4841 4842 if (!found_current) { 4843 st->cr(); 4844 st->print("=>" PTR_FORMAT " (exited) ", p2i(current)); 4845 current->print_on_error(st, buf, buflen); 4846 st->cr(); 4847 } 4848 st->cr(); 4849 4850 st->print_cr("Threads with active compile tasks:"); 4851 print_threads_compiling(st, buf, buflen); 4852 } 4853 4854 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) { 4855 ALL_JAVA_THREADS(thread) { 4856 if (thread->is_Compiler_thread()) { 4857 CompilerThread* ct = (CompilerThread*) thread; 4858 4859 // Keep task in local variable for NULL check. 4860 // ct->_task might be set to NULL by concurring compiler thread 4861 // because it completed the compilation. The task is never freed, 4862 // though, just returned to a free list. 4863 CompileTask* task = ct->task(); 4864 if (task != NULL) { 4865 thread->print_name_on_error(st, buf, buflen); 4866 st->print(" "); 4867 task->print(st, NULL, short_form, true); 4868 } 4869 } 4870 } 4871 } 4872 4873 4874 // Internal SpinLock and Mutex 4875 // Based on ParkEvent 4876 4877 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4878 // 4879 // We employ SpinLocks _only for low-contention, fixed-length 4880 // short-duration critical sections where we're concerned 4881 // about native mutex_t or HotSpot Mutex:: latency. 4882 // The mux construct provides a spin-then-block mutual exclusion 4883 // mechanism. 4884 // 4885 // Testing has shown that contention on the ListLock guarding gFreeList 4886 // is common. If we implement ListLock as a simple SpinLock it's common 4887 // for the JVM to devolve to yielding with little progress. This is true 4888 // despite the fact that the critical sections protected by ListLock are 4889 // extremely short. 4890 // 4891 // TODO-FIXME: ListLock should be of type SpinLock. 4892 // We should make this a 1st-class type, integrated into the lock 4893 // hierarchy as leaf-locks. Critically, the SpinLock structure 4894 // should have sufficient padding to avoid false-sharing and excessive 4895 // cache-coherency traffic. 4896 4897 4898 typedef volatile int SpinLockT; 4899 4900 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4901 if (Atomic::cmpxchg(adr, 0, 1) == 0) { 4902 return; // normal fast-path return 4903 } 4904 4905 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4906 int ctr = 0; 4907 int Yields = 0; 4908 for (;;) { 4909 while (*adr != 0) { 4910 ++ctr; 4911 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4912 if (Yields > 5) { 4913 os::naked_short_sleep(1); 4914 } else { 4915 os::naked_yield(); 4916 ++Yields; 4917 } 4918 } else { 4919 SpinPause(); 4920 } 4921 } 4922 if (Atomic::cmpxchg(adr, 0, 1) == 0) return; 4923 } 4924 } 4925 4926 void Thread::SpinRelease(volatile int * adr) { 4927 assert(*adr != 0, "invariant"); 4928 OrderAccess::fence(); // guarantee at least release consistency. 4929 // Roach-motel semantics. 4930 // It's safe if subsequent LDs and STs float "up" into the critical section, 4931 // but prior LDs and STs within the critical section can't be allowed 4932 // to reorder or float past the ST that releases the lock. 4933 // Loads and stores in the critical section - which appear in program 4934 // order before the store that releases the lock - must also appear 4935 // before the store that releases the lock in memory visibility order. 4936 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4937 // the ST of 0 into the lock-word which releases the lock, so fence 4938 // more than covers this on all platforms. 4939 *adr = 0; 4940 } 4941 4942 // muxAcquire and muxRelease: 4943 // 4944 // * muxAcquire and muxRelease support a single-word lock-word construct. 4945 // The LSB of the word is set IFF the lock is held. 4946 // The remainder of the word points to the head of a singly-linked list 4947 // of threads blocked on the lock. 4948 // 4949 // * The current implementation of muxAcquire-muxRelease uses its own 4950 // dedicated Thread._MuxEvent instance. If we're interested in 4951 // minimizing the peak number of extant ParkEvent instances then 4952 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4953 // as certain invariants were satisfied. Specifically, care would need 4954 // to be taken with regards to consuming unpark() "permits". 4955 // A safe rule of thumb is that a thread would never call muxAcquire() 4956 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4957 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4958 // consume an unpark() permit intended for monitorenter, for instance. 4959 // One way around this would be to widen the restricted-range semaphore 4960 // implemented in park(). Another alternative would be to provide 4961 // multiple instances of the PlatformEvent() for each thread. One 4962 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4963 // 4964 // * Usage: 4965 // -- Only as leaf locks 4966 // -- for short-term locking only as muxAcquire does not perform 4967 // thread state transitions. 4968 // 4969 // Alternatives: 4970 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4971 // but with parking or spin-then-park instead of pure spinning. 4972 // * Use Taura-Oyama-Yonenzawa locks. 4973 // * It's possible to construct a 1-0 lock if we encode the lockword as 4974 // (List,LockByte). Acquire will CAS the full lockword while Release 4975 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4976 // acquiring threads use timers (ParkTimed) to detect and recover from 4977 // the stranding window. Thread/Node structures must be aligned on 256-byte 4978 // boundaries by using placement-new. 4979 // * Augment MCS with advisory back-link fields maintained with CAS(). 4980 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4981 // The validity of the backlinks must be ratified before we trust the value. 4982 // If the backlinks are invalid the exiting thread must back-track through the 4983 // the forward links, which are always trustworthy. 4984 // * Add a successor indication. The LockWord is currently encoded as 4985 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4986 // to provide the usual futile-wakeup optimization. 4987 // See RTStt for details. 4988 // 4989 4990 4991 const intptr_t LOCKBIT = 1; 4992 4993 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4994 intptr_t w = Atomic::cmpxchg(Lock, (intptr_t)0, LOCKBIT); 4995 if (w == 0) return; 4996 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) { 4997 return; 4998 } 4999 5000 ParkEvent * const Self = Thread::current()->_MuxEvent; 5001 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 5002 for (;;) { 5003 int its = (os::is_MP() ? 100 : 0) + 1; 5004 5005 // Optional spin phase: spin-then-park strategy 5006 while (--its >= 0) { 5007 w = *Lock; 5008 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) { 5009 return; 5010 } 5011 } 5012 5013 Self->reset(); 5014 Self->OnList = intptr_t(Lock); 5015 // The following fence() isn't _strictly necessary as the subsequent 5016 // CAS() both serializes execution and ratifies the fetched *Lock value. 5017 OrderAccess::fence(); 5018 for (;;) { 5019 w = *Lock; 5020 if ((w & LOCKBIT) == 0) { 5021 if (Atomic::cmpxchg(Lock, w, w|LOCKBIT) == w) { 5022 Self->OnList = 0; // hygiene - allows stronger asserts 5023 return; 5024 } 5025 continue; // Interference -- *Lock changed -- Just retry 5026 } 5027 assert(w & LOCKBIT, "invariant"); 5028 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 5029 if (Atomic::cmpxchg(Lock, w, intptr_t(Self)|LOCKBIT) == w) break; 5030 } 5031 5032 while (Self->OnList != 0) { 5033 Self->park(); 5034 } 5035 } 5036 } 5037 5038 // Release() must extract a successor from the list and then wake that thread. 5039 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 5040 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 5041 // Release() would : 5042 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 5043 // (B) Extract a successor from the private list "in-hand" 5044 // (C) attempt to CAS() the residual back into *Lock over null. 5045 // If there were any newly arrived threads and the CAS() would fail. 5046 // In that case Release() would detach the RATs, re-merge the list in-hand 5047 // with the RATs and repeat as needed. Alternately, Release() might 5048 // detach and extract a successor, but then pass the residual list to the wakee. 5049 // The wakee would be responsible for reattaching and remerging before it 5050 // competed for the lock. 5051 // 5052 // Both "pop" and DMR are immune from ABA corruption -- there can be 5053 // multiple concurrent pushers, but only one popper or detacher. 5054 // This implementation pops from the head of the list. This is unfair, 5055 // but tends to provide excellent throughput as hot threads remain hot. 5056 // (We wake recently run threads first). 5057 // 5058 // All paths through muxRelease() will execute a CAS. 5059 // Release consistency -- We depend on the CAS in muxRelease() to provide full 5060 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 5061 // executed within the critical section are complete and globally visible before the 5062 // store (CAS) to the lock-word that releases the lock becomes globally visible. 5063 void Thread::muxRelease(volatile intptr_t * Lock) { 5064 for (;;) { 5065 const intptr_t w = Atomic::cmpxchg(Lock, LOCKBIT, (intptr_t)0); 5066 assert(w & LOCKBIT, "invariant"); 5067 if (w == LOCKBIT) return; 5068 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 5069 assert(List != NULL, "invariant"); 5070 assert(List->OnList == intptr_t(Lock), "invariant"); 5071 ParkEvent * const nxt = List->ListNext; 5072 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 5073 5074 // The following CAS() releases the lock and pops the head element. 5075 // The CAS() also ratifies the previously fetched lock-word value. 5076 if (Atomic::cmpxchg(Lock, w, intptr_t(nxt)) != w) { 5077 continue; 5078 } 5079 List->OnList = 0; 5080 OrderAccess::fence(); 5081 List->unpark(); 5082 return; 5083 } 5084 } 5085 5086 5087 void Threads::verify() { 5088 ALL_JAVA_THREADS(p) { 5089 p->verify(); 5090 } 5091 VMThread* thread = VMThread::vm_thread(); 5092 if (thread != NULL) thread->verify(); 5093 }