1 /* 2 * Copyright (c) 1997, 2019, 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 "classfile/classLoader.hpp" 28 #include "classfile/javaClasses.hpp" 29 #include "classfile/moduleEntry.hpp" 30 #include "classfile/systemDictionary.hpp" 31 #include "classfile/vmSymbols.hpp" 32 #include "code/codeCache.hpp" 33 #include "code/scopeDesc.hpp" 34 #include "compiler/compileBroker.hpp" 35 #include "compiler/compileTask.hpp" 36 #include "gc/shared/barrierSet.hpp" 37 #include "gc/shared/gcId.hpp" 38 #include "gc/shared/gcLocker.inline.hpp" 39 #include "gc/shared/workgroup.hpp" 40 #include "interpreter/interpreter.hpp" 41 #include "interpreter/linkResolver.hpp" 42 #include "interpreter/oopMapCache.hpp" 43 #include "jfr/jfrEvents.hpp" 44 #include "jvmtifiles/jvmtiEnv.hpp" 45 #include "logging/log.hpp" 46 #include "logging/logConfiguration.hpp" 47 #include "logging/logStream.hpp" 48 #include "memory/allocation.inline.hpp" 49 #include "memory/metaspaceShared.hpp" 50 #include "memory/oopFactory.hpp" 51 #include "memory/resourceArea.hpp" 52 #include "memory/universe.hpp" 53 #include "oops/access.inline.hpp" 54 #include "oops/instanceKlass.hpp" 55 #include "oops/objArrayOop.hpp" 56 #include "oops/oop.inline.hpp" 57 #include "oops/symbol.hpp" 58 #include "oops/typeArrayOop.inline.hpp" 59 #include "oops/verifyOopClosure.hpp" 60 #include "prims/jvm_misc.hpp" 61 #include "prims/jvmtiExport.hpp" 62 #include "prims/jvmtiThreadState.hpp" 63 #include "runtime/arguments.hpp" 64 #include "runtime/atomic.hpp" 65 #include "runtime/biasedLocking.hpp" 66 #include "runtime/fieldDescriptor.inline.hpp" 67 #include "runtime/flags/jvmFlagConstraintList.hpp" 68 #include "runtime/flags/jvmFlagRangeList.hpp" 69 #include "runtime/flags/jvmFlagWriteableList.hpp" 70 #include "runtime/deoptimization.hpp" 71 #include "runtime/frame.inline.hpp" 72 #include "runtime/handles.inline.hpp" 73 #include "runtime/handshake.hpp" 74 #include "runtime/init.hpp" 75 #include "runtime/interfaceSupport.inline.hpp" 76 #include "runtime/java.hpp" 77 #include "runtime/javaCalls.hpp" 78 #include "runtime/jniHandles.inline.hpp" 79 #include "runtime/jniPeriodicChecker.hpp" 80 #include "runtime/memprofiler.hpp" 81 #include "runtime/mutexLocker.hpp" 82 #include "runtime/objectMonitor.hpp" 83 #include "runtime/orderAccess.hpp" 84 #include "runtime/osThread.hpp" 85 #include "runtime/prefetch.inline.hpp" 86 #include "runtime/safepoint.hpp" 87 #include "runtime/safepointMechanism.inline.hpp" 88 #include "runtime/safepointVerifiers.hpp" 89 #include "runtime/sharedRuntime.hpp" 90 #include "runtime/statSampler.hpp" 91 #include "runtime/stubRoutines.hpp" 92 #include "runtime/sweeper.hpp" 93 #include "runtime/task.hpp" 94 #include "runtime/thread.inline.hpp" 95 #include "runtime/threadCritical.hpp" 96 #include "runtime/threadSMR.inline.hpp" 97 #include "runtime/threadStatisticalInfo.hpp" 98 #include "runtime/timer.hpp" 99 #include "runtime/timerTrace.hpp" 100 #include "runtime/vframe.inline.hpp" 101 #include "runtime/vframeArray.hpp" 102 #include "runtime/vframe_hp.hpp" 103 #include "runtime/vmThread.hpp" 104 #include "runtime/vmOperations.hpp" 105 #include "runtime/vm_version.hpp" 106 #include "services/attachListener.hpp" 107 #include "services/management.hpp" 108 #include "services/memTracker.hpp" 109 #include "services/threadService.hpp" 110 #include "utilities/align.hpp" 111 #include "utilities/copy.hpp" 112 #include "utilities/defaultStream.hpp" 113 #include "utilities/dtrace.hpp" 114 #include "utilities/events.hpp" 115 #include "utilities/macros.hpp" 116 #include "utilities/preserveException.hpp" 117 #include "utilities/singleWriterSynchronizer.hpp" 118 #include "utilities/vmError.hpp" 119 #if INCLUDE_JVMCI 120 #include "jvmci/jvmciCompiler.hpp" 121 #include "jvmci/jvmciRuntime.hpp" 122 #include "logging/logHandle.hpp" 123 #endif 124 #ifdef COMPILER1 125 #include "c1/c1_Compiler.hpp" 126 #endif 127 #ifdef COMPILER2 128 #include "opto/c2compiler.hpp" 129 #include "opto/idealGraphPrinter.hpp" 130 #endif 131 #if INCLUDE_RTM_OPT 132 #include "runtime/rtmLocking.hpp" 133 #endif 134 #if INCLUDE_JFR 135 #include "jfr/jfr.hpp" 136 #endif 137 138 // Initialization after module runtime initialization 139 void universe_post_module_init(); // must happen after call_initPhase2 140 141 #ifdef DTRACE_ENABLED 142 143 // Only bother with this argument setup if dtrace is available 144 145 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 146 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 147 148 #define DTRACE_THREAD_PROBE(probe, javathread) \ 149 { \ 150 ResourceMark rm(this); \ 151 int len = 0; \ 152 const char* name = (javathread)->get_thread_name(); \ 153 len = strlen(name); \ 154 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 155 (char *) name, len, \ 156 java_lang_Thread::thread_id((javathread)->threadObj()), \ 157 (uintptr_t) (javathread)->osthread()->thread_id(), \ 158 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 159 } 160 161 #else // ndef DTRACE_ENABLED 162 163 #define DTRACE_THREAD_PROBE(probe, javathread) 164 165 #endif // ndef DTRACE_ENABLED 166 167 #ifndef USE_LIBRARY_BASED_TLS_ONLY 168 // Current thread is maintained as a thread-local variable 169 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL; 170 #endif 171 172 // ======= Thread ======== 173 // Support for forcing alignment of thread objects for biased locking 174 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 175 if (UseBiasedLocking) { 176 const int alignment = markOopDesc::biased_lock_alignment; 177 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 178 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 179 : AllocateHeap(aligned_size, flags, CURRENT_PC, 180 AllocFailStrategy::RETURN_NULL); 181 void* aligned_addr = align_up(real_malloc_addr, alignment); 182 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 183 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 184 "JavaThread alignment code overflowed allocated storage"); 185 if (aligned_addr != real_malloc_addr) { 186 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 187 p2i(real_malloc_addr), 188 p2i(aligned_addr)); 189 } 190 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 191 return aligned_addr; 192 } else { 193 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 194 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 195 } 196 } 197 198 void Thread::operator delete(void* p) { 199 if (UseBiasedLocking) { 200 FreeHeap(((Thread*) p)->_real_malloc_address); 201 } else { 202 FreeHeap(p); 203 } 204 } 205 206 void JavaThread::smr_delete() { 207 if (_on_thread_list) { 208 ThreadsSMRSupport::smr_delete(this); 209 } else { 210 delete this; 211 } 212 } 213 214 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 215 // JavaThread 216 217 DEBUG_ONLY(Thread* Thread::_starting_thread = NULL;) 218 219 Thread::Thread() { 220 221 DEBUG_ONLY(_run_state = PRE_CALL_RUN;) 222 223 // stack and get_thread 224 set_stack_base(NULL); 225 set_stack_size(0); 226 set_self_raw_id(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 debug_only(_allow_allocation_count = 0;) 254 NOT_PRODUCT(_allow_safepoint_count = 0;) 255 NOT_PRODUCT(_skip_gcalot = false;) 256 _jvmti_env_iteration_count = 0; 257 set_allocated_bytes(0); 258 _vm_operation_started_count = 0; 259 _vm_operation_completed_count = 0; 260 _current_pending_monitor = NULL; 261 _current_pending_monitor_is_from_java = true; 262 _current_waiting_monitor = NULL; 263 _num_nested_signal = 0; 264 omFreeList = NULL; 265 omFreeCount = 0; 266 omFreeProvision = 32; 267 omInUseList = NULL; 268 omInUseCount = 0; 269 omShouldDeflateIdleMonitors = false; 270 271 #ifdef ASSERT 272 _visited_for_critical_count = false; 273 #endif 274 275 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, 276 Monitor::_safepoint_check_sometimes); 277 _suspend_flags = 0; 278 279 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 280 _hashStateX = os::random(); 281 _hashStateY = 842502087; 282 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 283 _hashStateW = 273326509; 284 285 _OnTrap = 0; 286 _Stalled = 0; 287 _TypeTag = 0x2BAD; 288 289 // Many of the following fields are effectively final - immutable 290 // Note that nascent threads can't use the Native Monitor-Mutex 291 // construct until the _MutexEvent is initialized ... 292 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 293 // we might instead use a stack of ParkEvents that we could provision on-demand. 294 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 295 // and ::Release() 296 _ParkEvent = ParkEvent::Allocate(this); 297 _SleepEvent = ParkEvent::Allocate(this); 298 _MuxEvent = ParkEvent::Allocate(this); 299 300 #ifdef CHECK_UNHANDLED_OOPS 301 if (CheckUnhandledOops) { 302 _unhandled_oops = new UnhandledOops(this); 303 } 304 #endif // CHECK_UNHANDLED_OOPS 305 #ifdef ASSERT 306 if (UseBiasedLocking) { 307 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 308 assert(this == _real_malloc_address || 309 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment), 310 "bug in forced alignment of thread objects"); 311 } 312 #endif // ASSERT 313 314 // Notify the barrier set that a thread is being created. The initial 315 // thread is created before the barrier set is available. The call to 316 // BarrierSet::on_thread_create() for this thread is therefore deferred 317 // to BarrierSet::set_barrier_set(). 318 BarrierSet* const barrier_set = BarrierSet::barrier_set(); 319 if (barrier_set != NULL) { 320 barrier_set->on_thread_create(this); 321 } else { 322 // Only the main thread should be created before the barrier set 323 // and that happens just before Thread::current is set. No other thread 324 // can attach as the VM is not created yet, so they can't execute this code. 325 // If the main thread creates other threads before the barrier set that is an error. 326 assert(Thread::current_or_null() == NULL, "creating thread before barrier set"); 327 } 328 } 329 330 void Thread::initialize_thread_current() { 331 #ifndef USE_LIBRARY_BASED_TLS_ONLY 332 assert(_thr_current == NULL, "Thread::current already initialized"); 333 _thr_current = this; 334 #endif 335 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized"); 336 ThreadLocalStorage::set_thread(this); 337 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 338 } 339 340 void Thread::clear_thread_current() { 341 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 342 #ifndef USE_LIBRARY_BASED_TLS_ONLY 343 _thr_current = NULL; 344 #endif 345 ThreadLocalStorage::set_thread(NULL); 346 } 347 348 void Thread::record_stack_base_and_size() { 349 // Note: at this point, Thread object is not yet initialized. Do not rely on 350 // any members being initialized. Do not rely on Thread::current() being set. 351 // If possible, refrain from doing anything which may crash or assert since 352 // quite probably those crash dumps will be useless. 353 set_stack_base(os::current_stack_base()); 354 set_stack_size(os::current_stack_size()); 355 356 #ifdef SOLARIS 357 if (os::is_primordial_thread()) { 358 os::Solaris::correct_stack_boundaries_for_primordial_thread(this); 359 } 360 #endif 361 362 // Set stack limits after thread is initialized. 363 if (is_Java_thread()) { 364 ((JavaThread*) this)->set_stack_overflow_limit(); 365 ((JavaThread*) this)->set_reserved_stack_activation(stack_base()); 366 } 367 } 368 369 #if INCLUDE_NMT 370 void Thread::register_thread_stack_with_NMT() { 371 MemTracker::record_thread_stack(stack_end(), stack_size()); 372 } 373 #endif // INCLUDE_NMT 374 375 void Thread::call_run() { 376 DEBUG_ONLY(_run_state = CALL_RUN;) 377 378 // At this point, Thread object should be fully initialized and 379 // Thread::current() should be set. 380 381 assert(Thread::current_or_null() != NULL, "current thread is unset"); 382 assert(Thread::current_or_null() == this, "current thread is wrong"); 383 384 // Perform common initialization actions 385 386 register_thread_stack_with_NMT(); 387 388 JFR_ONLY(Jfr::on_thread_start(this);) 389 390 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: " 391 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).", 392 os::current_thread_id(), p2i(stack_base() - stack_size()), 393 p2i(stack_base()), stack_size()/1024); 394 395 // Perform <ChildClass> initialization actions 396 DEBUG_ONLY(_run_state = PRE_RUN;) 397 this->pre_run(); 398 399 // Invoke <ChildClass>::run() 400 DEBUG_ONLY(_run_state = RUN;) 401 this->run(); 402 // Returned from <ChildClass>::run(). Thread finished. 403 404 // Perform common tear-down actions 405 406 assert(Thread::current_or_null() != NULL, "current thread is unset"); 407 assert(Thread::current_or_null() == this, "current thread is wrong"); 408 409 // Perform <ChildClass> tear-down actions 410 DEBUG_ONLY(_run_state = POST_RUN;) 411 this->post_run(); 412 413 // Note: at this point the thread object may already have deleted itself, 414 // so from here on do not dereference *this*. Not all thread types currently 415 // delete themselves when they terminate. But no thread should ever be deleted 416 // asynchronously with respect to its termination - that is what _run_state can 417 // be used to check. 418 419 assert(Thread::current_or_null() == NULL, "current thread still present"); 420 } 421 422 Thread::~Thread() { 423 424 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually 425 // get started due to errors etc. Any active thread should at least reach post_run 426 // before it is deleted (usually in post_run()). 427 assert(_run_state == PRE_CALL_RUN || 428 _run_state == POST_RUN, "Active Thread deleted before post_run(): " 429 "_run_state=%d", (int)_run_state); 430 431 // Notify the barrier set that a thread is being destroyed. Note that a barrier 432 // set might not be available if we encountered errors during bootstrapping. 433 BarrierSet* const barrier_set = BarrierSet::barrier_set(); 434 if (barrier_set != NULL) { 435 barrier_set->on_thread_destroy(this); 436 } 437 438 // stack_base can be NULL if the thread is never started or exited before 439 // record_stack_base_and_size called. Although, we would like to ensure 440 // that all started threads do call record_stack_base_and_size(), there is 441 // not proper way to enforce that. 442 #if INCLUDE_NMT 443 if (_stack_base != NULL) { 444 MemTracker::release_thread_stack(stack_end(), stack_size()); 445 #ifdef ASSERT 446 set_stack_base(NULL); 447 #endif 448 } 449 #endif // INCLUDE_NMT 450 451 // deallocate data structures 452 delete resource_area(); 453 // since the handle marks are using the handle area, we have to deallocated the root 454 // handle mark before deallocating the thread's handle area, 455 assert(last_handle_mark() != NULL, "check we have an element"); 456 delete last_handle_mark(); 457 assert(last_handle_mark() == NULL, "check we have reached the end"); 458 459 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 460 // We NULL out the fields for good hygiene. 461 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 462 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 463 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 464 465 delete handle_area(); 466 delete metadata_handles(); 467 468 // SR_handler uses this as a termination indicator - 469 // needs to happen before os::free_thread() 470 delete _SR_lock; 471 _SR_lock = NULL; 472 473 // osthread() can be NULL, if creation of thread failed. 474 if (osthread() != NULL) os::free_thread(osthread()); 475 476 // Clear Thread::current if thread is deleting itself and it has not 477 // already been done. This must be done before the memory is deallocated. 478 // Needed to ensure JNI correctly detects non-attached threads. 479 if (this == Thread::current_or_null()) { 480 Thread::clear_thread_current(); 481 } 482 483 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 484 } 485 486 #ifdef ASSERT 487 // A JavaThread is considered "dangling" if it is not the current 488 // thread, has been added the Threads list, the system is not at a 489 // safepoint and the Thread is not "protected". 490 // 491 void Thread::check_for_dangling_thread_pointer(Thread *thread) { 492 assert(!thread->is_Java_thread() || Thread::current() == thread || 493 !((JavaThread *) thread)->on_thread_list() || 494 SafepointSynchronize::is_at_safepoint() || 495 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread), 496 "possibility of dangling Thread pointer"); 497 } 498 #endif 499 500 ThreadPriority Thread::get_priority(const Thread* const thread) { 501 ThreadPriority priority; 502 // Can return an error! 503 (void)os::get_priority(thread, priority); 504 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 505 return priority; 506 } 507 508 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 509 debug_only(check_for_dangling_thread_pointer(thread);) 510 // Can return an error! 511 (void)os::set_priority(thread, priority); 512 } 513 514 515 void Thread::start(Thread* thread) { 516 // Start is different from resume in that its safety is guaranteed by context or 517 // being called from a Java method synchronized on the Thread object. 518 if (!DisableStartThread) { 519 if (thread->is_Java_thread()) { 520 // Initialize the thread state to RUNNABLE before starting this thread. 521 // Can not set it after the thread started because we do not know the 522 // exact thread state at that time. It could be in MONITOR_WAIT or 523 // in SLEEPING or some other state. 524 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 525 java_lang_Thread::RUNNABLE); 526 } 527 os::start_thread(thread); 528 } 529 } 530 531 // Enqueue a VM_Operation to do the job for us - sometime later 532 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 533 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 534 VMThread::execute(vm_stop); 535 } 536 537 538 // Check if an external suspend request has completed (or has been 539 // cancelled). Returns true if the thread is externally suspended and 540 // false otherwise. 541 // 542 // The bits parameter returns information about the code path through 543 // the routine. Useful for debugging: 544 // 545 // set in is_ext_suspend_completed(): 546 // 0x00000001 - routine was entered 547 // 0x00000010 - routine return false at end 548 // 0x00000100 - thread exited (return false) 549 // 0x00000200 - suspend request cancelled (return false) 550 // 0x00000400 - thread suspended (return true) 551 // 0x00001000 - thread is in a suspend equivalent state (return true) 552 // 0x00002000 - thread is native and walkable (return true) 553 // 0x00004000 - thread is native_trans and walkable (needed retry) 554 // 555 // set in wait_for_ext_suspend_completion(): 556 // 0x00010000 - routine was entered 557 // 0x00020000 - suspend request cancelled before loop (return false) 558 // 0x00040000 - thread suspended before loop (return true) 559 // 0x00080000 - suspend request cancelled in loop (return false) 560 // 0x00100000 - thread suspended in loop (return true) 561 // 0x00200000 - suspend not completed during retry loop (return false) 562 563 // Helper class for tracing suspend wait debug bits. 564 // 565 // 0x00000100 indicates that the target thread exited before it could 566 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 567 // 0x00080000 each indicate a cancelled suspend request so they don't 568 // count as wait failures either. 569 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 570 571 class TraceSuspendDebugBits : public StackObj { 572 private: 573 JavaThread * jt; 574 bool is_wait; 575 bool called_by_wait; // meaningful when !is_wait 576 uint32_t * bits; 577 578 public: 579 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 580 uint32_t *_bits) { 581 jt = _jt; 582 is_wait = _is_wait; 583 called_by_wait = _called_by_wait; 584 bits = _bits; 585 } 586 587 ~TraceSuspendDebugBits() { 588 if (!is_wait) { 589 #if 1 590 // By default, don't trace bits for is_ext_suspend_completed() calls. 591 // That trace is very chatty. 592 return; 593 #else 594 if (!called_by_wait) { 595 // If tracing for is_ext_suspend_completed() is enabled, then only 596 // trace calls to it from wait_for_ext_suspend_completion() 597 return; 598 } 599 #endif 600 } 601 602 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 603 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 604 MutexLocker ml(Threads_lock); // needed for get_thread_name() 605 ResourceMark rm; 606 607 tty->print_cr( 608 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 609 jt->get_thread_name(), *bits); 610 611 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 612 } 613 } 614 } 615 }; 616 #undef DEBUG_FALSE_BITS 617 618 619 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 620 uint32_t *bits) { 621 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 622 623 bool did_trans_retry = false; // only do thread_in_native_trans retry once 624 bool do_trans_retry; // flag to force the retry 625 626 *bits |= 0x00000001; 627 628 do { 629 do_trans_retry = false; 630 631 if (is_exiting()) { 632 // Thread is in the process of exiting. This is always checked 633 // first to reduce the risk of dereferencing a freed JavaThread. 634 *bits |= 0x00000100; 635 return false; 636 } 637 638 if (!is_external_suspend()) { 639 // Suspend request is cancelled. This is always checked before 640 // is_ext_suspended() to reduce the risk of a rogue resume 641 // confusing the thread that made the suspend request. 642 *bits |= 0x00000200; 643 return false; 644 } 645 646 if (is_ext_suspended()) { 647 // thread is suspended 648 *bits |= 0x00000400; 649 return true; 650 } 651 652 // Now that we no longer do hard suspends of threads running 653 // native code, the target thread can be changing thread state 654 // while we are in this routine: 655 // 656 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 657 // 658 // We save a copy of the thread state as observed at this moment 659 // and make our decision about suspend completeness based on the 660 // copy. This closes the race where the thread state is seen as 661 // _thread_in_native_trans in the if-thread_blocked check, but is 662 // seen as _thread_blocked in if-thread_in_native_trans check. 663 JavaThreadState save_state = thread_state(); 664 665 if (save_state == _thread_blocked && is_suspend_equivalent()) { 666 // If the thread's state is _thread_blocked and this blocking 667 // condition is known to be equivalent to a suspend, then we can 668 // consider the thread to be externally suspended. This means that 669 // the code that sets _thread_blocked has been modified to do 670 // self-suspension if the blocking condition releases. We also 671 // used to check for CONDVAR_WAIT here, but that is now covered by 672 // the _thread_blocked with self-suspension check. 673 // 674 // Return true since we wouldn't be here unless there was still an 675 // external suspend request. 676 *bits |= 0x00001000; 677 return true; 678 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 679 // Threads running native code will self-suspend on native==>VM/Java 680 // transitions. If its stack is walkable (should always be the case 681 // unless this function is called before the actual java_suspend() 682 // call), then the wait is done. 683 *bits |= 0x00002000; 684 return true; 685 } else if (!called_by_wait && !did_trans_retry && 686 save_state == _thread_in_native_trans && 687 frame_anchor()->walkable()) { 688 // The thread is transitioning from thread_in_native to another 689 // thread state. check_safepoint_and_suspend_for_native_trans() 690 // will force the thread to self-suspend. If it hasn't gotten 691 // there yet we may have caught the thread in-between the native 692 // code check above and the self-suspend. Lucky us. If we were 693 // called by wait_for_ext_suspend_completion(), then it 694 // will be doing the retries so we don't have to. 695 // 696 // Since we use the saved thread state in the if-statement above, 697 // there is a chance that the thread has already transitioned to 698 // _thread_blocked by the time we get here. In that case, we will 699 // make a single unnecessary pass through the logic below. This 700 // doesn't hurt anything since we still do the trans retry. 701 702 *bits |= 0x00004000; 703 704 // Once the thread leaves thread_in_native_trans for another 705 // thread state, we break out of this retry loop. We shouldn't 706 // need this flag to prevent us from getting back here, but 707 // sometimes paranoia is good. 708 did_trans_retry = true; 709 710 // We wait for the thread to transition to a more usable state. 711 for (int i = 1; i <= SuspendRetryCount; i++) { 712 // We used to do an "os::yield_all(i)" call here with the intention 713 // that yielding would increase on each retry. However, the parameter 714 // is ignored on Linux which means the yield didn't scale up. Waiting 715 // on the SR_lock below provides a much more predictable scale up for 716 // the delay. It also provides a simple/direct point to check for any 717 // safepoint requests from the VMThread 718 719 // temporarily drops SR_lock while doing wait with safepoint check 720 // (if we're a JavaThread - the WatcherThread can also call this) 721 // and increase delay with each retry 722 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 723 724 // check the actual thread state instead of what we saved above 725 if (thread_state() != _thread_in_native_trans) { 726 // the thread has transitioned to another thread state so 727 // try all the checks (except this one) one more time. 728 do_trans_retry = true; 729 break; 730 } 731 } // end retry loop 732 733 734 } 735 } while (do_trans_retry); 736 737 *bits |= 0x00000010; 738 return false; 739 } 740 741 // Wait for an external suspend request to complete (or be cancelled). 742 // Returns true if the thread is externally suspended and false otherwise. 743 // 744 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 745 uint32_t *bits) { 746 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 747 false /* !called_by_wait */, bits); 748 749 // local flag copies to minimize SR_lock hold time 750 bool is_suspended; 751 bool pending; 752 uint32_t reset_bits; 753 754 // set a marker so is_ext_suspend_completed() knows we are the caller 755 *bits |= 0x00010000; 756 757 // We use reset_bits to reinitialize the bits value at the top of 758 // each retry loop. This allows the caller to make use of any 759 // unused bits for their own marking purposes. 760 reset_bits = *bits; 761 762 { 763 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 764 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 765 delay, bits); 766 pending = is_external_suspend(); 767 } 768 // must release SR_lock to allow suspension to complete 769 770 if (!pending) { 771 // A cancelled suspend request is the only false return from 772 // is_ext_suspend_completed() that keeps us from entering the 773 // retry loop. 774 *bits |= 0x00020000; 775 return false; 776 } 777 778 if (is_suspended) { 779 *bits |= 0x00040000; 780 return true; 781 } 782 783 for (int i = 1; i <= retries; i++) { 784 *bits = reset_bits; // reinit to only track last retry 785 786 // We used to do an "os::yield_all(i)" call here with the intention 787 // that yielding would increase on each retry. However, the parameter 788 // is ignored on Linux which means the yield didn't scale up. Waiting 789 // on the SR_lock below provides a much more predictable scale up for 790 // the delay. It also provides a simple/direct point to check for any 791 // safepoint requests from the VMThread 792 793 { 794 MutexLocker ml(SR_lock()); 795 // wait with safepoint check (if we're a JavaThread - the WatcherThread 796 // can also call this) and increase delay with each retry 797 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 798 799 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 800 delay, bits); 801 802 // It is possible for the external suspend request to be cancelled 803 // (by a resume) before the actual suspend operation is completed. 804 // Refresh our local copy to see if we still need to wait. 805 pending = is_external_suspend(); 806 } 807 808 if (!pending) { 809 // A cancelled suspend request is the only false return from 810 // is_ext_suspend_completed() that keeps us from staying in the 811 // retry loop. 812 *bits |= 0x00080000; 813 return false; 814 } 815 816 if (is_suspended) { 817 *bits |= 0x00100000; 818 return true; 819 } 820 } // end retry loop 821 822 // thread did not suspend after all our retries 823 *bits |= 0x00200000; 824 return false; 825 } 826 827 // Called from API entry points which perform stack walking. If the 828 // associated JavaThread is the current thread, then wait_for_suspend 829 // is not used. Otherwise, it determines if we should wait for the 830 // "other" thread to complete external suspension. (NOTE: in future 831 // releases the suspension mechanism should be reimplemented so this 832 // is not necessary.) 833 // 834 bool 835 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) { 836 if (this != JavaThread::current()) { 837 // "other" threads require special handling. 838 if (wait_for_suspend) { 839 // We are allowed to wait for the external suspend to complete 840 // so give the other thread a chance to get suspended. 841 if (!wait_for_ext_suspend_completion(SuspendRetryCount, 842 SuspendRetryDelay, bits)) { 843 // Didn't make it so let the caller know. 844 return false; 845 } 846 } 847 // We aren't allowed to wait for the external suspend to complete 848 // so if the other thread isn't externally suspended we need to 849 // let the caller know. 850 else if (!is_ext_suspend_completed_with_lock(bits)) { 851 return false; 852 } 853 } 854 855 return true; 856 } 857 858 #ifndef PRODUCT 859 void JavaThread::record_jump(address target, address instr, const char* file, 860 int line) { 861 862 // This should not need to be atomic as the only way for simultaneous 863 // updates is via interrupts. Even then this should be rare or non-existent 864 // and we don't care that much anyway. 865 866 int index = _jmp_ring_index; 867 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 868 _jmp_ring[index]._target = (intptr_t) target; 869 _jmp_ring[index]._instruction = (intptr_t) instr; 870 _jmp_ring[index]._file = file; 871 _jmp_ring[index]._line = line; 872 } 873 #endif // PRODUCT 874 875 void Thread::interrupt(Thread* thread) { 876 debug_only(check_for_dangling_thread_pointer(thread);) 877 os::interrupt(thread); 878 } 879 880 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 881 debug_only(check_for_dangling_thread_pointer(thread);) 882 // Note: If clear_interrupted==false, this simply fetches and 883 // returns the value of the field osthread()->interrupted(). 884 return os::is_interrupted(thread, clear_interrupted); 885 } 886 887 888 // GC Support 889 bool Thread::claim_par_threads_do(uintx claim_token) { 890 uintx token = _threads_do_token; 891 if (token != claim_token) { 892 uintx res = Atomic::cmpxchg(claim_token, &_threads_do_token, token); 893 if (res == token) { 894 return true; 895 } 896 guarantee(res == claim_token, "invariant"); 897 } 898 return false; 899 } 900 901 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 902 active_handles()->oops_do(f); 903 // Do oop for ThreadShadow 904 f->do_oop((oop*)&_pending_exception); 905 handle_area()->oops_do(f); 906 907 // We scan thread local monitor lists here, and the remaining global 908 // monitors in ObjectSynchronizer::oops_do(). 909 ObjectSynchronizer::thread_local_used_oops_do(this, f); 910 } 911 912 void Thread::metadata_handles_do(void f(Metadata*)) { 913 // Only walk the Handles in Thread. 914 if (metadata_handles() != NULL) { 915 for (int i = 0; i< metadata_handles()->length(); i++) { 916 f(metadata_handles()->at(i)); 917 } 918 } 919 } 920 921 void Thread::print_on(outputStream* st, bool print_extended_info) const { 922 // get_priority assumes osthread initialized 923 if (osthread() != NULL) { 924 int os_prio; 925 if (os::get_native_priority(this, &os_prio) == OS_OK) { 926 st->print("os_prio=%d ", os_prio); 927 } 928 929 st->print("cpu=%.2fms ", 930 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0 931 ); 932 st->print("elapsed=%.2fs ", 933 _statistical_info.getElapsedTime() / 1000.0 934 ); 935 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) { 936 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes(); 937 st->print("allocated=" SIZE_FORMAT "%s ", 938 byte_size_in_proper_unit(allocated_bytes), 939 proper_unit_for_byte_size(allocated_bytes) 940 ); 941 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount()); 942 } 943 944 st->print("tid=" INTPTR_FORMAT " ", p2i(this)); 945 osthread()->print_on(st); 946 } 947 ThreadsSMRSupport::print_info_on(this, st); 948 st->print(" "); 949 debug_only(if (WizardMode) print_owned_locks_on(st);) 950 } 951 952 // Thread::print_on_error() is called by fatal error handler. Don't use 953 // any lock or allocate memory. 954 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 955 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates"); 956 957 if (is_VM_thread()) { st->print("VMThread"); } 958 else if (is_GC_task_thread()) { st->print("GCTaskThread"); } 959 else if (is_Watcher_thread()) { st->print("WatcherThread"); } 960 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); } 961 else { st->print("Thread"); } 962 963 if (is_Named_thread()) { 964 st->print(" \"%s\"", name()); 965 } 966 967 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 968 p2i(stack_end()), p2i(stack_base())); 969 970 if (osthread()) { 971 st->print(" [id=%d]", osthread()->thread_id()); 972 } 973 974 ThreadsSMRSupport::print_info_on(this, st); 975 } 976 977 void Thread::print_value_on(outputStream* st) const { 978 if (is_Named_thread()) { 979 st->print(" \"%s\" ", name()); 980 } 981 st->print(INTPTR_FORMAT, p2i(this)); // print address 982 } 983 984 #ifdef ASSERT 985 void Thread::print_owned_locks_on(outputStream* st) const { 986 Monitor *cur = _owned_locks; 987 if (cur == NULL) { 988 st->print(" (no locks) "); 989 } else { 990 st->print_cr(" Locks owned:"); 991 while (cur) { 992 cur->print_on(st); 993 cur = cur->next(); 994 } 995 } 996 } 997 998 static int ref_use_count = 0; 999 1000 bool Thread::owns_locks_but_compiled_lock() const { 1001 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 1002 if (cur != Compile_lock) return true; 1003 } 1004 return false; 1005 } 1006 1007 1008 #endif 1009 1010 #ifndef PRODUCT 1011 1012 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially 1013 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that 1014 // no locks which allow_vm_block's are held 1015 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 1016 // Check if current thread is allowed to block at a safepoint 1017 if (!(_allow_safepoint_count == 0)) { 1018 fatal("Possible safepoint reached by thread that does not allow it"); 1019 } 1020 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 1021 fatal("LEAF method calling lock?"); 1022 } 1023 1024 #ifdef ASSERT 1025 if (potential_vm_operation && is_Java_thread() 1026 && !Universe::is_bootstrapping()) { 1027 // Make sure we do not hold any locks that the VM thread also uses. 1028 // This could potentially lead to deadlocks 1029 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 1030 // Threads_lock is special, since the safepoint synchronization will not start before this is 1031 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 1032 // since it is used to transfer control between JavaThreads and the VMThread 1033 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 1034 if ((cur->allow_vm_block() && 1035 cur != Threads_lock && 1036 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 1037 cur != VMOperationRequest_lock && 1038 cur != VMOperationQueue_lock) || 1039 cur->rank() == Mutex::special) { 1040 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 1041 } 1042 } 1043 } 1044 1045 if (GCALotAtAllSafepoints) { 1046 // We could enter a safepoint here and thus have a gc 1047 InterfaceSupport::check_gc_alot(); 1048 } 1049 #endif 1050 } 1051 #endif 1052 1053 bool Thread::is_in_stack(address adr) const { 1054 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 1055 address end = os::current_stack_pointer(); 1056 // Allow non Java threads to call this without stack_base 1057 if (_stack_base == NULL) return true; 1058 if (stack_base() >= adr && adr >= end) return true; 1059 1060 return false; 1061 } 1062 1063 bool Thread::is_in_usable_stack(address adr) const { 1064 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0; 1065 size_t usable_stack_size = _stack_size - stack_guard_size; 1066 1067 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 1068 } 1069 1070 1071 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 1072 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 1073 // used for compilation in the future. If that change is made, the need for these methods 1074 // should be revisited, and they should be removed if possible. 1075 1076 bool Thread::is_lock_owned(address adr) const { 1077 return on_local_stack(adr); 1078 } 1079 1080 bool Thread::set_as_starting_thread() { 1081 assert(_starting_thread == NULL, "already initialized: " 1082 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread)); 1083 // NOTE: this must be called inside the main thread. 1084 DEBUG_ONLY(_starting_thread = this;) 1085 return os::create_main_thread((JavaThread*)this); 1086 } 1087 1088 static void initialize_class(Symbol* class_name, TRAPS) { 1089 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 1090 InstanceKlass::cast(klass)->initialize(CHECK); 1091 } 1092 1093 1094 // Creates the initial ThreadGroup 1095 static Handle create_initial_thread_group(TRAPS) { 1096 Handle system_instance = JavaCalls::construct_new_instance( 1097 SystemDictionary::ThreadGroup_klass(), 1098 vmSymbols::void_method_signature(), 1099 CHECK_NH); 1100 Universe::set_system_thread_group(system_instance()); 1101 1102 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 1103 Handle main_instance = JavaCalls::construct_new_instance( 1104 SystemDictionary::ThreadGroup_klass(), 1105 vmSymbols::threadgroup_string_void_signature(), 1106 system_instance, 1107 string, 1108 CHECK_NH); 1109 return main_instance; 1110 } 1111 1112 // Creates the initial Thread 1113 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 1114 TRAPS) { 1115 InstanceKlass* ik = SystemDictionary::Thread_klass(); 1116 assert(ik->is_initialized(), "must be"); 1117 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL); 1118 1119 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread 1120 // constructor calls Thread.current(), which must be set here for the 1121 // initial thread. 1122 java_lang_Thread::set_thread(thread_oop(), thread); 1123 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1124 thread->set_threadObj(thread_oop()); 1125 1126 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1127 1128 JavaValue result(T_VOID); 1129 JavaCalls::call_special(&result, thread_oop, 1130 ik, 1131 vmSymbols::object_initializer_name(), 1132 vmSymbols::threadgroup_string_void_signature(), 1133 thread_group, 1134 string, 1135 CHECK_NULL); 1136 return thread_oop(); 1137 } 1138 1139 char java_runtime_name[128] = ""; 1140 char java_runtime_version[128] = ""; 1141 1142 // extract the JRE name from java.lang.VersionProps.java_runtime_name 1143 static const char* get_java_runtime_name(TRAPS) { 1144 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1145 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1146 fieldDescriptor fd; 1147 bool found = k != NULL && 1148 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1149 vmSymbols::string_signature(), &fd); 1150 if (found) { 1151 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1152 if (name_oop == NULL) { 1153 return NULL; 1154 } 1155 const char* name = java_lang_String::as_utf8_string(name_oop, 1156 java_runtime_name, 1157 sizeof(java_runtime_name)); 1158 return name; 1159 } else { 1160 return NULL; 1161 } 1162 } 1163 1164 // extract the JRE version from java.lang.VersionProps.java_runtime_version 1165 static const char* get_java_runtime_version(TRAPS) { 1166 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1167 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1168 fieldDescriptor fd; 1169 bool found = k != NULL && 1170 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1171 vmSymbols::string_signature(), &fd); 1172 if (found) { 1173 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1174 if (name_oop == NULL) { 1175 return NULL; 1176 } 1177 const char* name = java_lang_String::as_utf8_string(name_oop, 1178 java_runtime_version, 1179 sizeof(java_runtime_version)); 1180 return name; 1181 } else { 1182 return NULL; 1183 } 1184 } 1185 1186 // General purpose hook into Java code, run once when the VM is initialized. 1187 // The Java library method itself may be changed independently from the VM. 1188 static void call_postVMInitHook(TRAPS) { 1189 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD); 1190 if (klass != NULL) { 1191 JavaValue result(T_VOID); 1192 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1193 vmSymbols::void_method_signature(), 1194 CHECK); 1195 } 1196 } 1197 1198 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 1199 bool daemon, TRAPS) { 1200 assert(thread_group.not_null(), "thread group should be specified"); 1201 assert(threadObj() == NULL, "should only create Java thread object once"); 1202 1203 InstanceKlass* ik = SystemDictionary::Thread_klass(); 1204 assert(ik->is_initialized(), "must be"); 1205 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK); 1206 1207 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon. 1208 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread 1209 // constructor calls Thread.current(), which must be set here. 1210 java_lang_Thread::set_thread(thread_oop(), this); 1211 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1212 set_threadObj(thread_oop()); 1213 1214 JavaValue result(T_VOID); 1215 if (thread_name != NULL) { 1216 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1217 // Thread gets assigned specified name and null target 1218 JavaCalls::call_special(&result, 1219 thread_oop, 1220 ik, 1221 vmSymbols::object_initializer_name(), 1222 vmSymbols::threadgroup_string_void_signature(), 1223 thread_group, 1224 name, 1225 THREAD); 1226 } else { 1227 // Thread gets assigned name "Thread-nnn" and null target 1228 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1229 JavaCalls::call_special(&result, 1230 thread_oop, 1231 ik, 1232 vmSymbols::object_initializer_name(), 1233 vmSymbols::threadgroup_runnable_void_signature(), 1234 thread_group, 1235 Handle(), 1236 THREAD); 1237 } 1238 1239 1240 if (daemon) { 1241 java_lang_Thread::set_daemon(thread_oop()); 1242 } 1243 1244 if (HAS_PENDING_EXCEPTION) { 1245 return; 1246 } 1247 1248 Klass* group = SystemDictionary::ThreadGroup_klass(); 1249 Handle threadObj(THREAD, this->threadObj()); 1250 1251 JavaCalls::call_special(&result, 1252 thread_group, 1253 group, 1254 vmSymbols::add_method_name(), 1255 vmSymbols::thread_void_signature(), 1256 threadObj, // Arg 1 1257 THREAD); 1258 } 1259 1260 // List of all NonJavaThreads and safe iteration over that list. 1261 1262 class NonJavaThread::List { 1263 public: 1264 NonJavaThread* volatile _head; 1265 SingleWriterSynchronizer _protect; 1266 1267 List() : _head(NULL), _protect() {} 1268 }; 1269 1270 NonJavaThread::List NonJavaThread::_the_list; 1271 1272 NonJavaThread::Iterator::Iterator() : 1273 _protect_enter(_the_list._protect.enter()), 1274 _current(OrderAccess::load_acquire(&_the_list._head)) 1275 {} 1276 1277 NonJavaThread::Iterator::~Iterator() { 1278 _the_list._protect.exit(_protect_enter); 1279 } 1280 1281 void NonJavaThread::Iterator::step() { 1282 assert(!end(), "precondition"); 1283 _current = OrderAccess::load_acquire(&_current->_next); 1284 } 1285 1286 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) { 1287 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!"); 1288 } 1289 1290 NonJavaThread::~NonJavaThread() { } 1291 1292 void NonJavaThread::add_to_the_list() { 1293 MutexLockerEx ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag); 1294 // Initialize BarrierSet-related data before adding to list. 1295 BarrierSet::barrier_set()->on_thread_attach(this); 1296 OrderAccess::release_store(&_next, _the_list._head); 1297 OrderAccess::release_store(&_the_list._head, this); 1298 } 1299 1300 void NonJavaThread::remove_from_the_list() { 1301 { 1302 MutexLockerEx ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag); 1303 // Cleanup BarrierSet-related data before removing from list. 1304 BarrierSet::barrier_set()->on_thread_detach(this); 1305 NonJavaThread* volatile* p = &_the_list._head; 1306 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) { 1307 if (t == this) { 1308 *p = _next; 1309 break; 1310 } 1311 } 1312 } 1313 // Wait for any in-progress iterators. Concurrent synchronize is not 1314 // allowed, so do it while holding a dedicated lock. Outside and distinct 1315 // from NJTList_lock in case an iteration attempts to lock it. 1316 MutexLockerEx ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag); 1317 _the_list._protect.synchronize(); 1318 _next = NULL; // Safe to drop the link now. 1319 } 1320 1321 void NonJavaThread::pre_run() { 1322 add_to_the_list(); 1323 1324 // This is slightly odd in that NamedThread is a subclass, but 1325 // in fact name() is defined in Thread 1326 assert(this->name() != NULL, "thread name was not set before it was started"); 1327 this->set_native_thread_name(this->name()); 1328 } 1329 1330 void NonJavaThread::post_run() { 1331 JFR_ONLY(Jfr::on_thread_exit(this);) 1332 remove_from_the_list(); 1333 // Ensure thread-local-storage is cleared before termination. 1334 Thread::clear_thread_current(); 1335 } 1336 1337 // NamedThread -- non-JavaThread subclasses with multiple 1338 // uniquely named instances should derive from this. 1339 NamedThread::NamedThread() : 1340 NonJavaThread(), 1341 _name(NULL), 1342 _processed_thread(NULL), 1343 _gc_id(GCId::undefined()) 1344 {} 1345 1346 NamedThread::~NamedThread() { 1347 if (_name != NULL) { 1348 FREE_C_HEAP_ARRAY(char, _name); 1349 _name = NULL; 1350 } 1351 } 1352 1353 void NamedThread::set_name(const char* format, ...) { 1354 guarantee(_name == NULL, "Only get to set name once."); 1355 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1356 guarantee(_name != NULL, "alloc failure"); 1357 va_list ap; 1358 va_start(ap, format); 1359 jio_vsnprintf(_name, max_name_len, format, ap); 1360 va_end(ap); 1361 } 1362 1363 void NamedThread::print_on(outputStream* st) const { 1364 st->print("\"%s\" ", name()); 1365 Thread::print_on(st); 1366 st->cr(); 1367 } 1368 1369 1370 // ======= WatcherThread ======== 1371 1372 // The watcher thread exists to simulate timer interrupts. It should 1373 // be replaced by an abstraction over whatever native support for 1374 // timer interrupts exists on the platform. 1375 1376 WatcherThread* WatcherThread::_watcher_thread = NULL; 1377 bool WatcherThread::_startable = false; 1378 volatile bool WatcherThread::_should_terminate = false; 1379 1380 WatcherThread::WatcherThread() : NonJavaThread() { 1381 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1382 if (os::create_thread(this, os::watcher_thread)) { 1383 _watcher_thread = this; 1384 1385 // Set the watcher thread to the highest OS priority which should not be 1386 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1387 // is created. The only normal thread using this priority is the reference 1388 // handler thread, which runs for very short intervals only. 1389 // If the VMThread's priority is not lower than the WatcherThread profiling 1390 // will be inaccurate. 1391 os::set_priority(this, MaxPriority); 1392 if (!DisableStartThread) { 1393 os::start_thread(this); 1394 } 1395 } 1396 } 1397 1398 int WatcherThread::sleep() const { 1399 // The WatcherThread does not participate in the safepoint protocol 1400 // for the PeriodicTask_lock because it is not a JavaThread. 1401 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1402 1403 if (_should_terminate) { 1404 // check for termination before we do any housekeeping or wait 1405 return 0; // we did not sleep. 1406 } 1407 1408 // remaining will be zero if there are no tasks, 1409 // causing the WatcherThread to sleep until a task is 1410 // enrolled 1411 int remaining = PeriodicTask::time_to_wait(); 1412 int time_slept = 0; 1413 1414 // we expect this to timeout - we only ever get unparked when 1415 // we should terminate or when a new task has been enrolled 1416 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1417 1418 jlong time_before_loop = os::javaTimeNanos(); 1419 1420 while (true) { 1421 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, 1422 remaining); 1423 jlong now = os::javaTimeNanos(); 1424 1425 if (remaining == 0) { 1426 // if we didn't have any tasks we could have waited for a long time 1427 // consider the time_slept zero and reset time_before_loop 1428 time_slept = 0; 1429 time_before_loop = now; 1430 } else { 1431 // need to recalculate since we might have new tasks in _tasks 1432 time_slept = (int) ((now - time_before_loop) / 1000000); 1433 } 1434 1435 // Change to task list or spurious wakeup of some kind 1436 if (timedout || _should_terminate) { 1437 break; 1438 } 1439 1440 remaining = PeriodicTask::time_to_wait(); 1441 if (remaining == 0) { 1442 // Last task was just disenrolled so loop around and wait until 1443 // another task gets enrolled 1444 continue; 1445 } 1446 1447 remaining -= time_slept; 1448 if (remaining <= 0) { 1449 break; 1450 } 1451 } 1452 1453 return time_slept; 1454 } 1455 1456 void WatcherThread::run() { 1457 assert(this == watcher_thread(), "just checking"); 1458 1459 this->set_active_handles(JNIHandleBlock::allocate_block()); 1460 while (true) { 1461 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1462 assert(watcher_thread() == this, "thread consistency check"); 1463 1464 // Calculate how long it'll be until the next PeriodicTask work 1465 // should be done, and sleep that amount of time. 1466 int time_waited = sleep(); 1467 1468 if (VMError::is_error_reported()) { 1469 // A fatal error has happened, the error handler(VMError::report_and_die) 1470 // should abort JVM after creating an error log file. However in some 1471 // rare cases, the error handler itself might deadlock. Here periodically 1472 // check for error reporting timeouts, and if it happens, just proceed to 1473 // abort the VM. 1474 1475 // This code is in WatcherThread because WatcherThread wakes up 1476 // periodically so the fatal error handler doesn't need to do anything; 1477 // also because the WatcherThread is less likely to crash than other 1478 // threads. 1479 1480 for (;;) { 1481 // Note: we use naked sleep in this loop because we want to avoid using 1482 // any kind of VM infrastructure which may be broken at this point. 1483 if (VMError::check_timeout()) { 1484 // We hit error reporting timeout. Error reporting was interrupted and 1485 // will be wrapping things up now (closing files etc). Give it some more 1486 // time, then quit the VM. 1487 os::naked_short_sleep(200); 1488 // Print a message to stderr. 1489 fdStream err(defaultStream::output_fd()); 1490 err.print_raw_cr("# [ timer expired, abort... ]"); 1491 // skip atexit/vm_exit/vm_abort hooks 1492 os::die(); 1493 } 1494 1495 // Wait a second, then recheck for timeout. 1496 os::naked_short_sleep(999); 1497 } 1498 } 1499 1500 if (_should_terminate) { 1501 // check for termination before posting the next tick 1502 break; 1503 } 1504 1505 PeriodicTask::real_time_tick(time_waited); 1506 } 1507 1508 // Signal that it is terminated 1509 { 1510 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1511 _watcher_thread = NULL; 1512 Terminator_lock->notify_all(); 1513 } 1514 } 1515 1516 void WatcherThread::start() { 1517 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1518 1519 if (watcher_thread() == NULL && _startable) { 1520 _should_terminate = false; 1521 // Create the single instance of WatcherThread 1522 new WatcherThread(); 1523 } 1524 } 1525 1526 void WatcherThread::make_startable() { 1527 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1528 _startable = true; 1529 } 1530 1531 void WatcherThread::stop() { 1532 { 1533 // Follow normal safepoint aware lock enter protocol since the 1534 // WatcherThread is stopped by another JavaThread. 1535 MutexLocker ml(PeriodicTask_lock); 1536 _should_terminate = true; 1537 1538 WatcherThread* watcher = watcher_thread(); 1539 if (watcher != NULL) { 1540 // unpark the WatcherThread so it can see that it should terminate 1541 watcher->unpark(); 1542 } 1543 } 1544 1545 MutexLocker mu(Terminator_lock); 1546 1547 while (watcher_thread() != NULL) { 1548 // This wait should make safepoint checks, wait without a timeout, 1549 // and wait as a suspend-equivalent condition. 1550 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1551 Mutex::_as_suspend_equivalent_flag); 1552 } 1553 } 1554 1555 void WatcherThread::unpark() { 1556 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1557 PeriodicTask_lock->notify(); 1558 } 1559 1560 void WatcherThread::print_on(outputStream* st) const { 1561 st->print("\"%s\" ", name()); 1562 Thread::print_on(st); 1563 st->cr(); 1564 } 1565 1566 // ======= JavaThread ======== 1567 1568 #if INCLUDE_JVMCI 1569 1570 jlong* JavaThread::_jvmci_old_thread_counters; 1571 1572 bool jvmci_counters_include(JavaThread* thread) { 1573 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); 1574 } 1575 1576 void JavaThread::collect_counters(typeArrayOop array) { 1577 if (JVMCICounterSize > 0) { 1578 JavaThreadIteratorWithHandle jtiwh; 1579 for (int i = 0; i < array->length(); i++) { 1580 array->long_at_put(i, _jvmci_old_thread_counters[i]); 1581 } 1582 for (; JavaThread *tp = jtiwh.next(); ) { 1583 if (jvmci_counters_include(tp)) { 1584 for (int i = 0; i < array->length(); i++) { 1585 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]); 1586 } 1587 } 1588 } 1589 } 1590 } 1591 1592 #endif // INCLUDE_JVMCI 1593 1594 // A JavaThread is a normal Java thread 1595 1596 void JavaThread::initialize() { 1597 // Initialize fields 1598 1599 set_saved_exception_pc(NULL); 1600 set_threadObj(NULL); 1601 _anchor.clear(); 1602 set_entry_point(NULL); 1603 set_jni_functions(jni_functions()); 1604 set_callee_target(NULL); 1605 set_vm_result(NULL); 1606 set_vm_result_2(NULL); 1607 set_vframe_array_head(NULL); 1608 set_vframe_array_last(NULL); 1609 set_deferred_locals(NULL); 1610 set_deopt_mark(NULL); 1611 set_deopt_compiled_method(NULL); 1612 clear_must_deopt_id(); 1613 set_monitor_chunks(NULL); 1614 set_next(NULL); 1615 _on_thread_list = false; 1616 set_thread_state(_thread_new); 1617 _terminated = _not_terminated; 1618 _array_for_gc = NULL; 1619 _suspend_equivalent = false; 1620 _in_deopt_handler = 0; 1621 _doing_unsafe_access = false; 1622 _stack_guard_state = stack_guard_unused; 1623 #if INCLUDE_JVMCI 1624 _pending_monitorenter = false; 1625 _pending_deoptimization = -1; 1626 _pending_failed_speculation = 0; 1627 _pending_transfer_to_interpreter = false; 1628 _adjusting_comp_level = false; 1629 _in_retryable_allocation = false; 1630 _jvmci._alternate_call_target = NULL; 1631 assert(_jvmci._implicit_exception_pc == NULL, "must be"); 1632 if (JVMCICounterSize > 0) { 1633 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 1634 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize); 1635 } else { 1636 _jvmci_counters = NULL; 1637 } 1638 #endif // INCLUDE_JVMCI 1639 _reserved_stack_activation = NULL; // stack base not known yet 1640 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1641 _exception_pc = 0; 1642 _exception_handler_pc = 0; 1643 _is_method_handle_return = 0; 1644 _jvmti_thread_state= NULL; 1645 _should_post_on_exceptions_flag = JNI_FALSE; 1646 _interp_only_mode = 0; 1647 _special_runtime_exit_condition = _no_async_condition; 1648 _pending_async_exception = NULL; 1649 _thread_stat = NULL; 1650 _thread_stat = new ThreadStatistics(); 1651 _blocked_on_compilation = false; 1652 _jni_active_critical = 0; 1653 _pending_jni_exception_check_fn = NULL; 1654 _do_not_unlock_if_synchronized = false; 1655 _cached_monitor_info = NULL; 1656 _parker = Parker::Allocate(this); 1657 1658 #ifndef PRODUCT 1659 _jmp_ring_index = 0; 1660 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1661 record_jump(NULL, NULL, NULL, 0); 1662 } 1663 #endif // PRODUCT 1664 1665 // Setup safepoint state info for this thread 1666 ThreadSafepointState::create(this); 1667 1668 debug_only(_java_call_counter = 0); 1669 1670 // JVMTI PopFrame support 1671 _popframe_condition = popframe_inactive; 1672 _popframe_preserved_args = NULL; 1673 _popframe_preserved_args_size = 0; 1674 _frames_to_pop_failed_realloc = 0; 1675 1676 if (SafepointMechanism::uses_thread_local_poll()) { 1677 SafepointMechanism::initialize_header(this); 1678 } 1679 1680 _class_to_be_initialized = NULL; 1681 1682 pd_initialize(); 1683 } 1684 1685 JavaThread::JavaThread(bool is_attaching_via_jni) : 1686 Thread() { 1687 initialize(); 1688 if (is_attaching_via_jni) { 1689 _jni_attach_state = _attaching_via_jni; 1690 } else { 1691 _jni_attach_state = _not_attaching_via_jni; 1692 } 1693 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1694 } 1695 1696 bool JavaThread::reguard_stack(address cur_sp) { 1697 if (_stack_guard_state != stack_guard_yellow_reserved_disabled 1698 && _stack_guard_state != stack_guard_reserved_disabled) { 1699 return true; // Stack already guarded or guard pages not needed. 1700 } 1701 1702 if (register_stack_overflow()) { 1703 // For those architectures which have separate register and 1704 // memory stacks, we must check the register stack to see if 1705 // it has overflowed. 1706 return false; 1707 } 1708 1709 // Java code never executes within the yellow zone: the latter is only 1710 // there to provoke an exception during stack banging. If java code 1711 // is executing there, either StackShadowPages should be larger, or 1712 // some exception code in c1, c2 or the interpreter isn't unwinding 1713 // when it should. 1714 guarantee(cur_sp > stack_reserved_zone_base(), 1715 "not enough space to reguard - increase StackShadowPages"); 1716 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) { 1717 enable_stack_yellow_reserved_zone(); 1718 if (reserved_stack_activation() != stack_base()) { 1719 set_reserved_stack_activation(stack_base()); 1720 } 1721 } else if (_stack_guard_state == stack_guard_reserved_disabled) { 1722 set_reserved_stack_activation(stack_base()); 1723 enable_stack_reserved_zone(); 1724 } 1725 return true; 1726 } 1727 1728 bool JavaThread::reguard_stack(void) { 1729 return reguard_stack(os::current_stack_pointer()); 1730 } 1731 1732 1733 void JavaThread::block_if_vm_exited() { 1734 if (_terminated == _vm_exited) { 1735 // _vm_exited is set at safepoint, and Threads_lock is never released 1736 // we will block here forever 1737 Threads_lock->lock_without_safepoint_check(); 1738 ShouldNotReachHere(); 1739 } 1740 } 1741 1742 1743 // Remove this ifdef when C1 is ported to the compiler interface. 1744 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1745 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1746 1747 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1748 Thread() { 1749 initialize(); 1750 _jni_attach_state = _not_attaching_via_jni; 1751 set_entry_point(entry_point); 1752 // Create the native thread itself. 1753 // %note runtime_23 1754 os::ThreadType thr_type = os::java_thread; 1755 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1756 os::java_thread; 1757 os::create_thread(this, thr_type, stack_sz); 1758 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1759 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1760 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1761 // the exception consists of creating the exception object & initializing it, initialization 1762 // will leave the VM via a JavaCall and then all locks must be unlocked). 1763 // 1764 // The thread is still suspended when we reach here. Thread must be explicit started 1765 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1766 // by calling Threads:add. The reason why this is not done here, is because the thread 1767 // object must be fully initialized (take a look at JVM_Start) 1768 } 1769 1770 JavaThread::~JavaThread() { 1771 1772 // JSR166 -- return the parker to the free list 1773 Parker::Release(_parker); 1774 _parker = NULL; 1775 1776 // Free any remaining previous UnrollBlock 1777 vframeArray* old_array = vframe_array_last(); 1778 1779 if (old_array != NULL) { 1780 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1781 old_array->set_unroll_block(NULL); 1782 delete old_info; 1783 delete old_array; 1784 } 1785 1786 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1787 if (deferred != NULL) { 1788 // This can only happen if thread is destroyed before deoptimization occurs. 1789 assert(deferred->length() != 0, "empty array!"); 1790 do { 1791 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1792 deferred->remove_at(0); 1793 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1794 delete dlv; 1795 } while (deferred->length() != 0); 1796 delete deferred; 1797 } 1798 1799 // All Java related clean up happens in exit 1800 ThreadSafepointState::destroy(this); 1801 if (_thread_stat != NULL) delete _thread_stat; 1802 1803 #if INCLUDE_JVMCI 1804 if (JVMCICounterSize > 0) { 1805 if (jvmci_counters_include(this)) { 1806 for (int i = 0; i < JVMCICounterSize; i++) { 1807 _jvmci_old_thread_counters[i] += _jvmci_counters[i]; 1808 } 1809 } 1810 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); 1811 } 1812 #endif // INCLUDE_JVMCI 1813 } 1814 1815 1816 // First JavaThread specific code executed by a new Java thread. 1817 void JavaThread::pre_run() { 1818 // empty - see comments in run() 1819 } 1820 1821 // The main routine called by a new Java thread. This isn't overridden 1822 // by subclasses, instead different subclasses define a different "entry_point" 1823 // which defines the actual logic for that kind of thread. 1824 void JavaThread::run() { 1825 // initialize thread-local alloc buffer related fields 1826 this->initialize_tlab(); 1827 1828 // Used to test validity of stack trace backs. 1829 // This can't be moved into pre_run() else we invalidate 1830 // the requirement that thread_main_inner is lower on 1831 // the stack. Consequently all the initialization logic 1832 // stays here in run() rather than pre_run(). 1833 this->record_base_of_stack_pointer(); 1834 1835 this->create_stack_guard_pages(); 1836 1837 this->cache_global_variables(); 1838 1839 // Thread is now sufficiently initialized to be handled by the safepoint code as being 1840 // in the VM. Change thread state from _thread_new to _thread_in_vm 1841 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm); 1842 // Before a thread is on the threads list it is always safe, so after leaving the 1843 // _thread_new we should emit a instruction barrier. The distance to modified code 1844 // from here is probably far enough, but this is consistent and safe. 1845 OrderAccess::cross_modify_fence(); 1846 1847 assert(JavaThread::current() == this, "sanity check"); 1848 assert(!Thread::current()->owns_locks(), "sanity check"); 1849 1850 DTRACE_THREAD_PROBE(start, this); 1851 1852 // This operation might block. We call that after all safepoint checks for a new thread has 1853 // been completed. 1854 this->set_active_handles(JNIHandleBlock::allocate_block()); 1855 1856 if (JvmtiExport::should_post_thread_life()) { 1857 JvmtiExport::post_thread_start(this); 1858 1859 } 1860 1861 // We call another function to do the rest so we are sure that the stack addresses used 1862 // from there will be lower than the stack base just computed. 1863 thread_main_inner(); 1864 } 1865 1866 void JavaThread::thread_main_inner() { 1867 assert(JavaThread::current() == this, "sanity check"); 1868 assert(this->threadObj() != NULL, "just checking"); 1869 1870 // Execute thread entry point unless this thread has a pending exception 1871 // or has been stopped before starting. 1872 // Note: Due to JVM_StopThread we can have pending exceptions already! 1873 if (!this->has_pending_exception() && 1874 !java_lang_Thread::is_stillborn(this->threadObj())) { 1875 { 1876 ResourceMark rm(this); 1877 this->set_native_thread_name(this->get_thread_name()); 1878 } 1879 HandleMark hm(this); 1880 this->entry_point()(this, this); 1881 } 1882 1883 DTRACE_THREAD_PROBE(stop, this); 1884 1885 // Cleanup is handled in post_run() 1886 } 1887 1888 // Shared teardown for all JavaThreads 1889 void JavaThread::post_run() { 1890 this->exit(false); 1891 // Defer deletion to here to ensure 'this' is still referenceable in call_run 1892 // for any shared tear-down. 1893 this->smr_delete(); 1894 } 1895 1896 static void ensure_join(JavaThread* thread) { 1897 // We do not need to grab the Threads_lock, since we are operating on ourself. 1898 Handle threadObj(thread, thread->threadObj()); 1899 assert(threadObj.not_null(), "java thread object must exist"); 1900 ObjectLocker lock(threadObj, thread); 1901 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1902 thread->clear_pending_exception(); 1903 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1904 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1905 // Clear the native thread instance - this makes isAlive return false and allows the join() 1906 // to complete once we've done the notify_all below 1907 java_lang_Thread::set_thread(threadObj(), NULL); 1908 lock.notify_all(thread); 1909 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1910 thread->clear_pending_exception(); 1911 } 1912 1913 static bool is_daemon(oop threadObj) { 1914 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)); 1915 } 1916 1917 // For any new cleanup additions, please check to see if they need to be applied to 1918 // cleanup_failed_attach_current_thread as well. 1919 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1920 assert(this == JavaThread::current(), "thread consistency check"); 1921 1922 elapsedTimer _timer_exit_phase1; 1923 elapsedTimer _timer_exit_phase2; 1924 elapsedTimer _timer_exit_phase3; 1925 elapsedTimer _timer_exit_phase4; 1926 1927 if (log_is_enabled(Debug, os, thread, timer)) { 1928 _timer_exit_phase1.start(); 1929 } 1930 1931 HandleMark hm(this); 1932 Handle uncaught_exception(this, this->pending_exception()); 1933 this->clear_pending_exception(); 1934 Handle threadObj(this, this->threadObj()); 1935 assert(threadObj.not_null(), "Java thread object should be created"); 1936 1937 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1938 { 1939 EXCEPTION_MARK; 1940 1941 CLEAR_PENDING_EXCEPTION; 1942 } 1943 if (!destroy_vm) { 1944 if (uncaught_exception.not_null()) { 1945 EXCEPTION_MARK; 1946 // Call method Thread.dispatchUncaughtException(). 1947 Klass* thread_klass = SystemDictionary::Thread_klass(); 1948 JavaValue result(T_VOID); 1949 JavaCalls::call_virtual(&result, 1950 threadObj, thread_klass, 1951 vmSymbols::dispatchUncaughtException_name(), 1952 vmSymbols::throwable_void_signature(), 1953 uncaught_exception, 1954 THREAD); 1955 if (HAS_PENDING_EXCEPTION) { 1956 ResourceMark rm(this); 1957 jio_fprintf(defaultStream::error_stream(), 1958 "\nException: %s thrown from the UncaughtExceptionHandler" 1959 " in thread \"%s\"\n", 1960 pending_exception()->klass()->external_name(), 1961 get_thread_name()); 1962 CLEAR_PENDING_EXCEPTION; 1963 } 1964 } 1965 JFR_ONLY(Jfr::on_java_thread_dismantle(this);) 1966 1967 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1968 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1969 // is deprecated anyhow. 1970 if (!is_Compiler_thread()) { 1971 int count = 3; 1972 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1973 EXCEPTION_MARK; 1974 JavaValue result(T_VOID); 1975 Klass* thread_klass = SystemDictionary::Thread_klass(); 1976 JavaCalls::call_virtual(&result, 1977 threadObj, thread_klass, 1978 vmSymbols::exit_method_name(), 1979 vmSymbols::void_method_signature(), 1980 THREAD); 1981 CLEAR_PENDING_EXCEPTION; 1982 } 1983 } 1984 // notify JVMTI 1985 if (JvmtiExport::should_post_thread_life()) { 1986 JvmtiExport::post_thread_end(this); 1987 } 1988 1989 // We have notified the agents that we are exiting, before we go on, 1990 // we must check for a pending external suspend request and honor it 1991 // in order to not surprise the thread that made the suspend request. 1992 while (true) { 1993 { 1994 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1995 if (!is_external_suspend()) { 1996 set_terminated(_thread_exiting); 1997 ThreadService::current_thread_exiting(this, is_daemon(threadObj())); 1998 break; 1999 } 2000 // Implied else: 2001 // Things get a little tricky here. We have a pending external 2002 // suspend request, but we are holding the SR_lock so we 2003 // can't just self-suspend. So we temporarily drop the lock 2004 // and then self-suspend. 2005 } 2006 2007 ThreadBlockInVM tbivm(this); 2008 java_suspend_self(); 2009 2010 // We're done with this suspend request, but we have to loop around 2011 // and check again. Eventually we will get SR_lock without a pending 2012 // external suspend request and will be able to mark ourselves as 2013 // exiting. 2014 } 2015 // no more external suspends are allowed at this point 2016 } else { 2017 assert(!is_terminated() && !is_exiting(), "must not be exiting"); 2018 // before_exit() has already posted JVMTI THREAD_END events 2019 } 2020 2021 if (log_is_enabled(Debug, os, thread, timer)) { 2022 _timer_exit_phase1.stop(); 2023 _timer_exit_phase2.start(); 2024 } 2025 2026 // Capture daemon status before the thread is marked as terminated. 2027 bool daemon = is_daemon(threadObj()); 2028 2029 // Notify waiters on thread object. This has to be done after exit() is called 2030 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 2031 // group should have the destroyed bit set before waiters are notified). 2032 ensure_join(this); 2033 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 2034 2035 if (log_is_enabled(Debug, os, thread, timer)) { 2036 _timer_exit_phase2.stop(); 2037 _timer_exit_phase3.start(); 2038 } 2039 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 2040 // held by this thread must be released. The spec does not distinguish 2041 // between JNI-acquired and regular Java monitors. We can only see 2042 // regular Java monitors here if monitor enter-exit matching is broken. 2043 // 2044 // ensure_join() ignores IllegalThreadStateExceptions, and so does 2045 // ObjectSynchronizer::release_monitors_owned_by_thread(). 2046 if (exit_type == jni_detach) { 2047 // Sanity check even though JNI DetachCurrentThread() would have 2048 // returned JNI_ERR if there was a Java frame. JavaThread exit 2049 // should be done executing Java code by the time we get here. 2050 assert(!this->has_last_Java_frame(), 2051 "should not have a Java frame when detaching or exiting"); 2052 ObjectSynchronizer::release_monitors_owned_by_thread(this); 2053 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 2054 } 2055 2056 // These things needs to be done while we are still a Java Thread. Make sure that thread 2057 // is in a consistent state, in case GC happens 2058 JFR_ONLY(Jfr::on_thread_exit(this);) 2059 2060 if (active_handles() != NULL) { 2061 JNIHandleBlock* block = active_handles(); 2062 set_active_handles(NULL); 2063 JNIHandleBlock::release_block(block); 2064 } 2065 2066 if (free_handle_block() != NULL) { 2067 JNIHandleBlock* block = free_handle_block(); 2068 set_free_handle_block(NULL); 2069 JNIHandleBlock::release_block(block); 2070 } 2071 2072 // These have to be removed while this is still a valid thread. 2073 remove_stack_guard_pages(); 2074 2075 if (UseTLAB) { 2076 tlab().retire(); 2077 } 2078 2079 if (JvmtiEnv::environments_might_exist()) { 2080 JvmtiExport::cleanup_thread(this); 2081 } 2082 2083 // We must flush any deferred card marks and other various GC barrier 2084 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer) 2085 // before removing a thread from the list of active threads. 2086 BarrierSet::barrier_set()->on_thread_detach(this); 2087 2088 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").", 2089 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", 2090 os::current_thread_id()); 2091 2092 if (log_is_enabled(Debug, os, thread, timer)) { 2093 _timer_exit_phase3.stop(); 2094 _timer_exit_phase4.start(); 2095 } 2096 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 2097 Threads::remove(this, daemon); 2098 2099 if (log_is_enabled(Debug, os, thread, timer)) { 2100 _timer_exit_phase4.stop(); 2101 ResourceMark rm(this); 2102 log_debug(os, thread, timer)("name='%s'" 2103 ", exit-phase1=" JLONG_FORMAT 2104 ", exit-phase2=" JLONG_FORMAT 2105 ", exit-phase3=" JLONG_FORMAT 2106 ", exit-phase4=" JLONG_FORMAT, 2107 get_thread_name(), 2108 _timer_exit_phase1.milliseconds(), 2109 _timer_exit_phase2.milliseconds(), 2110 _timer_exit_phase3.milliseconds(), 2111 _timer_exit_phase4.milliseconds()); 2112 } 2113 } 2114 2115 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) { 2116 if (active_handles() != NULL) { 2117 JNIHandleBlock* block = active_handles(); 2118 set_active_handles(NULL); 2119 JNIHandleBlock::release_block(block); 2120 } 2121 2122 if (free_handle_block() != NULL) { 2123 JNIHandleBlock* block = free_handle_block(); 2124 set_free_handle_block(NULL); 2125 JNIHandleBlock::release_block(block); 2126 } 2127 2128 // These have to be removed while this is still a valid thread. 2129 remove_stack_guard_pages(); 2130 2131 if (UseTLAB) { 2132 tlab().retire(); 2133 } 2134 2135 BarrierSet::barrier_set()->on_thread_detach(this); 2136 2137 Threads::remove(this, is_daemon); 2138 this->smr_delete(); 2139 } 2140 2141 JavaThread* JavaThread::active() { 2142 Thread* thread = Thread::current(); 2143 if (thread->is_Java_thread()) { 2144 return (JavaThread*) thread; 2145 } else { 2146 assert(thread->is_VM_thread(), "this must be a vm thread"); 2147 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2148 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2149 assert(ret->is_Java_thread(), "must be a Java thread"); 2150 return ret; 2151 } 2152 } 2153 2154 bool JavaThread::is_lock_owned(address adr) const { 2155 if (Thread::is_lock_owned(adr)) return true; 2156 2157 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2158 if (chunk->contains(adr)) return true; 2159 } 2160 2161 return false; 2162 } 2163 2164 2165 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2166 chunk->set_next(monitor_chunks()); 2167 set_monitor_chunks(chunk); 2168 } 2169 2170 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2171 guarantee(monitor_chunks() != NULL, "must be non empty"); 2172 if (monitor_chunks() == chunk) { 2173 set_monitor_chunks(chunk->next()); 2174 } else { 2175 MonitorChunk* prev = monitor_chunks(); 2176 while (prev->next() != chunk) prev = prev->next(); 2177 prev->set_next(chunk->next()); 2178 } 2179 } 2180 2181 // JVM support. 2182 2183 // Note: this function shouldn't block if it's called in 2184 // _thread_in_native_trans state (such as from 2185 // check_special_condition_for_native_trans()). 2186 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2187 2188 if (has_last_Java_frame() && has_async_condition()) { 2189 // If we are at a polling page safepoint (not a poll return) 2190 // then we must defer async exception because live registers 2191 // will be clobbered by the exception path. Poll return is 2192 // ok because the call we a returning from already collides 2193 // with exception handling registers and so there is no issue. 2194 // (The exception handling path kills call result registers but 2195 // this is ok since the exception kills the result anyway). 2196 2197 if (is_at_poll_safepoint()) { 2198 // if the code we are returning to has deoptimized we must defer 2199 // the exception otherwise live registers get clobbered on the 2200 // exception path before deoptimization is able to retrieve them. 2201 // 2202 RegisterMap map(this, false); 2203 frame caller_fr = last_frame().sender(&map); 2204 assert(caller_fr.is_compiled_frame(), "what?"); 2205 if (caller_fr.is_deoptimized_frame()) { 2206 log_info(exceptions)("deferred async exception at compiled safepoint"); 2207 return; 2208 } 2209 } 2210 } 2211 2212 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2213 if (condition == _no_async_condition) { 2214 // Conditions have changed since has_special_runtime_exit_condition() 2215 // was called: 2216 // - if we were here only because of an external suspend request, 2217 // then that was taken care of above (or cancelled) so we are done 2218 // - if we were here because of another async request, then it has 2219 // been cleared between the has_special_runtime_exit_condition() 2220 // and now so again we are done 2221 return; 2222 } 2223 2224 // Check for pending async. exception 2225 if (_pending_async_exception != NULL) { 2226 // Only overwrite an already pending exception, if it is not a threadDeath. 2227 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2228 2229 // We cannot call Exceptions::_throw(...) here because we cannot block 2230 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2231 2232 LogTarget(Info, exceptions) lt; 2233 if (lt.is_enabled()) { 2234 ResourceMark rm; 2235 LogStream ls(lt); 2236 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); 2237 if (has_last_Java_frame()) { 2238 frame f = last_frame(); 2239 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); 2240 } 2241 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name()); 2242 } 2243 _pending_async_exception = NULL; 2244 clear_has_async_exception(); 2245 } 2246 } 2247 2248 if (check_unsafe_error && 2249 condition == _async_unsafe_access_error && !has_pending_exception()) { 2250 condition = _no_async_condition; // done 2251 switch (thread_state()) { 2252 case _thread_in_vm: { 2253 JavaThread* THREAD = this; 2254 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2255 } 2256 case _thread_in_native: { 2257 ThreadInVMfromNative tiv(this); 2258 JavaThread* THREAD = this; 2259 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2260 } 2261 case _thread_in_Java: { 2262 ThreadInVMfromJava tiv(this); 2263 JavaThread* THREAD = this; 2264 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2265 } 2266 default: 2267 ShouldNotReachHere(); 2268 } 2269 } 2270 2271 assert(condition == _no_async_condition || has_pending_exception() || 2272 (!check_unsafe_error && condition == _async_unsafe_access_error), 2273 "must have handled the async condition, if no exception"); 2274 } 2275 2276 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2277 // 2278 // Check for pending external suspend. 2279 // If JNIEnv proxies are allowed, don't self-suspend if the target 2280 // thread is not the current thread. In older versions of jdbx, jdbx 2281 // threads could call into the VM with another thread's JNIEnv so we 2282 // can be here operating on behalf of a suspended thread (4432884). 2283 bool do_self_suspend = is_external_suspend_with_lock(); 2284 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2285 frame_anchor()->make_walkable(this); 2286 java_suspend_self_with_safepoint_check(); 2287 } 2288 2289 // We might be here for reasons in addition to the self-suspend request 2290 // so check for other async requests. 2291 if (check_asyncs) { 2292 check_and_handle_async_exceptions(); 2293 } 2294 2295 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);) 2296 } 2297 2298 void JavaThread::send_thread_stop(oop java_throwable) { 2299 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2300 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2301 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2302 2303 // Do not throw asynchronous exceptions against the compiler thread 2304 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2305 if (!can_call_java()) return; 2306 2307 { 2308 // Actually throw the Throwable against the target Thread - however 2309 // only if there is no thread death exception installed already. 2310 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2311 // If the topmost frame is a runtime stub, then we are calling into 2312 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2313 // must deoptimize the caller before continuing, as the compiled exception handler table 2314 // may not be valid 2315 if (has_last_Java_frame()) { 2316 frame f = last_frame(); 2317 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2318 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2319 RegisterMap reg_map(this, UseBiasedLocking); 2320 frame compiled_frame = f.sender(®_map); 2321 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2322 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2323 } 2324 } 2325 } 2326 2327 // Set async. pending exception in thread. 2328 set_pending_async_exception(java_throwable); 2329 2330 if (log_is_enabled(Info, exceptions)) { 2331 ResourceMark rm; 2332 log_info(exceptions)("Pending Async. exception installed of type: %s", 2333 InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2334 } 2335 // for AbortVMOnException flag 2336 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name()); 2337 } 2338 } 2339 2340 2341 // Interrupt thread so it will wake up from a potential wait() 2342 Thread::interrupt(this); 2343 } 2344 2345 // External suspension mechanism. 2346 // 2347 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2348 // to any VM_locks and it is at a transition 2349 // Self-suspension will happen on the transition out of the vm. 2350 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2351 // 2352 // Guarantees on return: 2353 // + Target thread will not execute any new bytecode (that's why we need to 2354 // force a safepoint) 2355 // + Target thread will not enter any new monitors 2356 // 2357 void JavaThread::java_suspend() { 2358 ThreadsListHandle tlh; 2359 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) { 2360 return; 2361 } 2362 2363 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2364 if (!is_external_suspend()) { 2365 // a racing resume has cancelled us; bail out now 2366 return; 2367 } 2368 2369 // suspend is done 2370 uint32_t debug_bits = 0; 2371 // Warning: is_ext_suspend_completed() may temporarily drop the 2372 // SR_lock to allow the thread to reach a stable thread state if 2373 // it is currently in a transient thread state. 2374 if (is_ext_suspend_completed(false /* !called_by_wait */, 2375 SuspendRetryDelay, &debug_bits)) { 2376 return; 2377 } 2378 } 2379 2380 if (Thread::current() == this) { 2381 // Safely self-suspend. 2382 // If we don't do this explicitly it will implicitly happen 2383 // before we transition back to Java, and on some other thread-state 2384 // transition paths, but not as we exit a JVM TI SuspendThread call. 2385 // As SuspendThread(current) must not return (until resumed) we must 2386 // self-suspend here. 2387 ThreadBlockInVM tbivm(this); 2388 java_suspend_self(); 2389 } else { 2390 VM_ThreadSuspend vm_suspend; 2391 VMThread::execute(&vm_suspend); 2392 } 2393 } 2394 2395 // Part II of external suspension. 2396 // A JavaThread self suspends when it detects a pending external suspend 2397 // request. This is usually on transitions. It is also done in places 2398 // where continuing to the next transition would surprise the caller, 2399 // e.g., monitor entry. 2400 // 2401 // Returns the number of times that the thread self-suspended. 2402 // 2403 // Note: DO NOT call java_suspend_self() when you just want to block current 2404 // thread. java_suspend_self() is the second stage of cooperative 2405 // suspension for external suspend requests and should only be used 2406 // to complete an external suspend request. 2407 // 2408 int JavaThread::java_suspend_self() { 2409 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()"); 2410 int ret = 0; 2411 2412 // we are in the process of exiting so don't suspend 2413 if (is_exiting()) { 2414 clear_external_suspend(); 2415 return ret; 2416 } 2417 2418 assert(_anchor.walkable() || 2419 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2420 "must have walkable stack"); 2421 2422 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2423 2424 assert(!this->is_ext_suspended(), 2425 "a thread trying to self-suspend should not already be suspended"); 2426 2427 if (this->is_suspend_equivalent()) { 2428 // If we are self-suspending as a result of the lifting of a 2429 // suspend equivalent condition, then the suspend_equivalent 2430 // flag is not cleared until we set the ext_suspended flag so 2431 // that wait_for_ext_suspend_completion() returns consistent 2432 // results. 2433 this->clear_suspend_equivalent(); 2434 } 2435 2436 // A racing resume may have cancelled us before we grabbed SR_lock 2437 // above. Or another external suspend request could be waiting for us 2438 // by the time we return from SR_lock()->wait(). The thread 2439 // that requested the suspension may already be trying to walk our 2440 // stack and if we return now, we can change the stack out from under 2441 // it. This would be a "bad thing (TM)" and cause the stack walker 2442 // to crash. We stay self-suspended until there are no more pending 2443 // external suspend requests. 2444 while (is_external_suspend()) { 2445 ret++; 2446 this->set_ext_suspended(); 2447 2448 // _ext_suspended flag is cleared by java_resume() 2449 while (is_ext_suspended()) { 2450 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2451 } 2452 } 2453 return ret; 2454 } 2455 2456 // Helper routine to set up the correct thread state before calling java_suspend_self. 2457 // This is called when regular thread-state transition helpers can't be used because 2458 // we can be in various states, in particular _thread_in_native_trans. 2459 // Because this thread is external suspended the safepoint code will count it as at 2460 // a safepoint, regardless of what its actual current thread-state is. But 2461 // is_ext_suspend_completed() may be waiting to see a thread transition from 2462 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly 2463 // to _thread_blocked. The problem with setting thread state directly is that a 2464 // safepoint could happen just after java_suspend_self() returns after being resumed, 2465 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint 2466 // after restoring the state to make sure we won't leave while a safepoint is in progress. 2467 // However, not all initial-states are allowed when performing a safepoint check, as we 2468 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states 2469 // only _thread_in_native is possible when executing this code (based on our two callers). 2470 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter 2471 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state, 2472 // and so we don't need the explicit safepoint check. 2473 2474 void JavaThread::java_suspend_self_with_safepoint_check() { 2475 assert(this == Thread::current(), "invariant"); 2476 JavaThreadState state = thread_state(); 2477 set_thread_state(_thread_blocked); 2478 java_suspend_self(); 2479 set_thread_state_fence(state); 2480 // Since we are not using a regular thread-state transition helper here, 2481 // we must manually emit the instruction barrier after leaving a safe state. 2482 OrderAccess::cross_modify_fence(); 2483 if (state != _thread_in_native) { 2484 SafepointMechanism::block_if_requested(this); 2485 } 2486 } 2487 2488 #ifdef ASSERT 2489 // Verify the JavaThread has not yet been published in the Threads::list, and 2490 // hence doesn't need protection from concurrent access at this stage. 2491 void JavaThread::verify_not_published() { 2492 // Cannot create a ThreadsListHandle here and check !tlh.includes(this) 2493 // since an unpublished JavaThread doesn't participate in the 2494 // Thread-SMR protocol for keeping a ThreadsList alive. 2495 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!"); 2496 } 2497 #endif 2498 2499 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2500 // progress or when _suspend_flags is non-zero. 2501 // Current thread needs to self-suspend if there is a suspend request and/or 2502 // block if a safepoint is in progress. 2503 // Async exception ISN'T checked. 2504 // Note only the ThreadInVMfromNative transition can call this function 2505 // directly and when thread state is _thread_in_native_trans 2506 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2507 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2508 2509 JavaThread *curJT = JavaThread::current(); 2510 bool do_self_suspend = thread->is_external_suspend(); 2511 2512 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2513 2514 // If JNIEnv proxies are allowed, don't self-suspend if the target 2515 // thread is not the current thread. In older versions of jdbx, jdbx 2516 // threads could call into the VM with another thread's JNIEnv so we 2517 // can be here operating on behalf of a suspended thread (4432884). 2518 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2519 thread->java_suspend_self_with_safepoint_check(); 2520 } else { 2521 SafepointMechanism::block_if_requested(curJT); 2522 } 2523 2524 if (thread->is_deopt_suspend()) { 2525 thread->clear_deopt_suspend(); 2526 RegisterMap map(thread, false); 2527 frame f = thread->last_frame(); 2528 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2529 f = f.sender(&map); 2530 } 2531 if (f.id() == thread->must_deopt_id()) { 2532 thread->clear_must_deopt_id(); 2533 f.deoptimize(thread); 2534 } else { 2535 fatal("missed deoptimization!"); 2536 } 2537 } 2538 2539 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);) 2540 } 2541 2542 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2543 // progress or when _suspend_flags is non-zero. 2544 // Current thread needs to self-suspend if there is a suspend request and/or 2545 // block if a safepoint is in progress. 2546 // Also check for pending async exception (not including unsafe access error). 2547 // Note only the native==>VM/Java barriers can call this function and when 2548 // thread state is _thread_in_native_trans. 2549 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2550 check_safepoint_and_suspend_for_native_trans(thread); 2551 2552 if (thread->has_async_exception()) { 2553 // We are in _thread_in_native_trans state, don't handle unsafe 2554 // access error since that may block. 2555 thread->check_and_handle_async_exceptions(false); 2556 } 2557 } 2558 2559 // This is a variant of the normal 2560 // check_special_condition_for_native_trans with slightly different 2561 // semantics for use by critical native wrappers. It does all the 2562 // normal checks but also performs the transition back into 2563 // thread_in_Java state. This is required so that critical natives 2564 // can potentially block and perform a GC if they are the last thread 2565 // exiting the GCLocker. 2566 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2567 check_special_condition_for_native_trans(thread); 2568 2569 // Finish the transition 2570 thread->set_thread_state(_thread_in_Java); 2571 2572 if (thread->do_critical_native_unlock()) { 2573 ThreadInVMfromJavaNoAsyncException tiv(thread); 2574 GCLocker::unlock_critical(thread); 2575 thread->clear_critical_native_unlock(); 2576 } 2577 } 2578 2579 // We need to guarantee the Threads_lock here, since resumes are not 2580 // allowed during safepoint synchronization 2581 // Can only resume from an external suspension 2582 void JavaThread::java_resume() { 2583 assert_locked_or_safepoint(Threads_lock); 2584 2585 // Sanity check: thread is gone, has started exiting or the thread 2586 // was not externally suspended. 2587 ThreadsListHandle tlh; 2588 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) { 2589 return; 2590 } 2591 2592 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2593 2594 clear_external_suspend(); 2595 2596 if (is_ext_suspended()) { 2597 clear_ext_suspended(); 2598 SR_lock()->notify_all(); 2599 } 2600 } 2601 2602 size_t JavaThread::_stack_red_zone_size = 0; 2603 size_t JavaThread::_stack_yellow_zone_size = 0; 2604 size_t JavaThread::_stack_reserved_zone_size = 0; 2605 size_t JavaThread::_stack_shadow_zone_size = 0; 2606 2607 void JavaThread::create_stack_guard_pages() { 2608 if (!os::uses_stack_guard_pages() || 2609 _stack_guard_state != stack_guard_unused || 2610 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) { 2611 log_info(os, thread)("Stack guard page creation for thread " 2612 UINTX_FORMAT " disabled", os::current_thread_id()); 2613 return; 2614 } 2615 address low_addr = stack_end(); 2616 size_t len = stack_guard_zone_size(); 2617 2618 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page"); 2619 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size"); 2620 2621 int must_commit = os::must_commit_stack_guard_pages(); 2622 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2623 2624 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) { 2625 log_warning(os, thread)("Attempt to allocate stack guard pages failed."); 2626 return; 2627 } 2628 2629 if (os::guard_memory((char *) low_addr, len)) { 2630 _stack_guard_state = stack_guard_enabled; 2631 } else { 2632 log_warning(os, thread)("Attempt to protect stack guard pages failed (" 2633 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2634 if (os::uncommit_memory((char *) low_addr, len)) { 2635 log_warning(os, thread)("Attempt to deallocate stack guard pages failed."); 2636 } 2637 return; 2638 } 2639 2640 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: " 2641 PTR_FORMAT "-" PTR_FORMAT ".", 2642 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2643 } 2644 2645 void JavaThread::remove_stack_guard_pages() { 2646 assert(Thread::current() == this, "from different thread"); 2647 if (_stack_guard_state == stack_guard_unused) return; 2648 address low_addr = stack_end(); 2649 size_t len = stack_guard_zone_size(); 2650 2651 if (os::must_commit_stack_guard_pages()) { 2652 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2653 _stack_guard_state = stack_guard_unused; 2654 } else { 2655 log_warning(os, thread)("Attempt to deallocate stack guard pages failed (" 2656 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2657 return; 2658 } 2659 } else { 2660 if (_stack_guard_state == stack_guard_unused) return; 2661 if (os::unguard_memory((char *) low_addr, len)) { 2662 _stack_guard_state = stack_guard_unused; 2663 } else { 2664 log_warning(os, thread)("Attempt to unprotect stack guard pages failed (" 2665 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2666 return; 2667 } 2668 } 2669 2670 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: " 2671 PTR_FORMAT "-" PTR_FORMAT ".", 2672 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2673 } 2674 2675 void JavaThread::enable_stack_reserved_zone() { 2676 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state"); 2677 2678 // The base notation is from the stack's point of view, growing downward. 2679 // We need to adjust it to work correctly with guard_memory() 2680 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2681 2682 guarantee(base < stack_base(),"Error calculating stack reserved zone"); 2683 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone"); 2684 2685 if (os::guard_memory((char *) base, stack_reserved_zone_size())) { 2686 _stack_guard_state = stack_guard_enabled; 2687 } else { 2688 warning("Attempt to guard stack reserved zone failed."); 2689 } 2690 enable_register_stack_guard(); 2691 } 2692 2693 void JavaThread::disable_stack_reserved_zone() { 2694 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state"); 2695 2696 // Simply return if called for a thread that does not use guard pages. 2697 if (_stack_guard_state != stack_guard_enabled) return; 2698 2699 // The base notation is from the stack's point of view, growing downward. 2700 // We need to adjust it to work correctly with guard_memory() 2701 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2702 2703 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) { 2704 _stack_guard_state = stack_guard_reserved_disabled; 2705 } else { 2706 warning("Attempt to unguard stack reserved zone failed."); 2707 } 2708 disable_register_stack_guard(); 2709 } 2710 2711 void JavaThread::enable_stack_yellow_reserved_zone() { 2712 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2713 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2714 2715 // The base notation is from the stacks point of view, growing downward. 2716 // We need to adjust it to work correctly with guard_memory() 2717 address base = stack_red_zone_base(); 2718 2719 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2720 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2721 2722 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) { 2723 _stack_guard_state = stack_guard_enabled; 2724 } else { 2725 warning("Attempt to guard stack yellow zone failed."); 2726 } 2727 enable_register_stack_guard(); 2728 } 2729 2730 void JavaThread::disable_stack_yellow_reserved_zone() { 2731 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2732 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled"); 2733 2734 // Simply return if called for a thread that does not use guard pages. 2735 if (_stack_guard_state == stack_guard_unused) return; 2736 2737 // The base notation is from the stacks point of view, growing downward. 2738 // We need to adjust it to work correctly with guard_memory() 2739 address base = stack_red_zone_base(); 2740 2741 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) { 2742 _stack_guard_state = stack_guard_yellow_reserved_disabled; 2743 } else { 2744 warning("Attempt to unguard stack yellow zone failed."); 2745 } 2746 disable_register_stack_guard(); 2747 } 2748 2749 void JavaThread::enable_stack_red_zone() { 2750 // The base notation is from the stacks point of view, growing downward. 2751 // We need to adjust it to work correctly with guard_memory() 2752 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2753 address base = stack_red_zone_base() - stack_red_zone_size(); 2754 2755 guarantee(base < stack_base(), "Error calculating stack red zone"); 2756 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2757 2758 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2759 warning("Attempt to guard stack red zone failed."); 2760 } 2761 } 2762 2763 void JavaThread::disable_stack_red_zone() { 2764 // The base notation is from the stacks point of view, growing downward. 2765 // We need to adjust it to work correctly with guard_memory() 2766 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2767 address base = stack_red_zone_base() - stack_red_zone_size(); 2768 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2769 warning("Attempt to unguard stack red zone failed."); 2770 } 2771 } 2772 2773 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2774 // ignore is there is no stack 2775 if (!has_last_Java_frame()) return; 2776 // traverse the stack frames. Starts from top frame. 2777 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2778 frame* fr = fst.current(); 2779 f(fr, fst.register_map()); 2780 } 2781 } 2782 2783 2784 #ifndef PRODUCT 2785 // Deoptimization 2786 // Function for testing deoptimization 2787 void JavaThread::deoptimize() { 2788 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2789 StackFrameStream fst(this, UseBiasedLocking); 2790 bool deopt = false; // Dump stack only if a deopt actually happens. 2791 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2792 // Iterate over all frames in the thread and deoptimize 2793 for (; !fst.is_done(); fst.next()) { 2794 if (fst.current()->can_be_deoptimized()) { 2795 2796 if (only_at) { 2797 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2798 // consists of comma or carriage return separated numbers so 2799 // search for the current bci in that string. 2800 address pc = fst.current()->pc(); 2801 nmethod* nm = (nmethod*) fst.current()->cb(); 2802 ScopeDesc* sd = nm->scope_desc_at(pc); 2803 char buffer[8]; 2804 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2805 size_t len = strlen(buffer); 2806 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2807 while (found != NULL) { 2808 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2809 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2810 // Check that the bci found is bracketed by terminators. 2811 break; 2812 } 2813 found = strstr(found + 1, buffer); 2814 } 2815 if (!found) { 2816 continue; 2817 } 2818 } 2819 2820 if (DebugDeoptimization && !deopt) { 2821 deopt = true; // One-time only print before deopt 2822 tty->print_cr("[BEFORE Deoptimization]"); 2823 trace_frames(); 2824 trace_stack(); 2825 } 2826 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2827 } 2828 } 2829 2830 if (DebugDeoptimization && deopt) { 2831 tty->print_cr("[AFTER Deoptimization]"); 2832 trace_frames(); 2833 } 2834 } 2835 2836 2837 // Make zombies 2838 void JavaThread::make_zombies() { 2839 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2840 if (fst.current()->can_be_deoptimized()) { 2841 // it is a Java nmethod 2842 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2843 nm->make_not_entrant(); 2844 } 2845 } 2846 } 2847 #endif // PRODUCT 2848 2849 2850 void JavaThread::deoptimized_wrt_marked_nmethods() { 2851 if (!has_last_Java_frame()) return; 2852 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2853 StackFrameStream fst(this, UseBiasedLocking); 2854 for (; !fst.is_done(); fst.next()) { 2855 if (fst.current()->should_be_deoptimized()) { 2856 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2857 } 2858 } 2859 } 2860 2861 2862 // If the caller is a NamedThread, then remember, in the current scope, 2863 // the given JavaThread in its _processed_thread field. 2864 class RememberProcessedThread: public StackObj { 2865 NamedThread* _cur_thr; 2866 public: 2867 RememberProcessedThread(JavaThread* jthr) { 2868 Thread* thread = Thread::current(); 2869 if (thread->is_Named_thread()) { 2870 _cur_thr = (NamedThread *)thread; 2871 _cur_thr->set_processed_thread(jthr); 2872 } else { 2873 _cur_thr = NULL; 2874 } 2875 } 2876 2877 ~RememberProcessedThread() { 2878 if (_cur_thr) { 2879 _cur_thr->set_processed_thread(NULL); 2880 } 2881 } 2882 }; 2883 2884 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 2885 // Verify that the deferred card marks have been flushed. 2886 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2887 2888 // Traverse the GCHandles 2889 Thread::oops_do(f, cf); 2890 2891 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2892 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2893 2894 if (has_last_Java_frame()) { 2895 // Record JavaThread to GC thread 2896 RememberProcessedThread rpt(this); 2897 2898 // traverse the registered growable array 2899 if (_array_for_gc != NULL) { 2900 for (int index = 0; index < _array_for_gc->length(); index++) { 2901 f->do_oop(_array_for_gc->adr_at(index)); 2902 } 2903 } 2904 2905 // Traverse the monitor chunks 2906 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2907 chunk->oops_do(f); 2908 } 2909 2910 // Traverse the execution stack 2911 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2912 fst.current()->oops_do(f, cf, fst.register_map()); 2913 } 2914 } 2915 2916 // callee_target is never live across a gc point so NULL it here should 2917 // it still contain a methdOop. 2918 2919 set_callee_target(NULL); 2920 2921 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2922 // If we have deferred set_locals there might be oops waiting to be 2923 // written 2924 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2925 if (list != NULL) { 2926 for (int i = 0; i < list->length(); i++) { 2927 list->at(i)->oops_do(f); 2928 } 2929 } 2930 2931 // Traverse instance variables at the end since the GC may be moving things 2932 // around using this function 2933 f->do_oop((oop*) &_threadObj); 2934 f->do_oop((oop*) &_vm_result); 2935 f->do_oop((oop*) &_exception_oop); 2936 f->do_oop((oop*) &_pending_async_exception); 2937 2938 if (jvmti_thread_state() != NULL) { 2939 jvmti_thread_state()->oops_do(f); 2940 } 2941 } 2942 2943 #ifdef ASSERT 2944 void JavaThread::verify_states_for_handshake() { 2945 // This checks that the thread has a correct frame state during a handshake. 2946 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2947 (has_last_Java_frame() && java_call_counter() > 0), 2948 "unexpected frame info: has_last_frame=%d, java_call_counter=%d", 2949 has_last_Java_frame(), java_call_counter()); 2950 } 2951 #endif 2952 2953 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2954 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2955 (has_last_Java_frame() && java_call_counter() > 0), 2956 "unexpected frame info: has_last_frame=%d, java_call_counter=%d", 2957 has_last_Java_frame(), java_call_counter()); 2958 2959 if (has_last_Java_frame()) { 2960 // Traverse the execution stack 2961 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2962 fst.current()->nmethods_do(cf); 2963 } 2964 } 2965 } 2966 2967 void JavaThread::metadata_do(MetadataClosure* f) { 2968 if (has_last_Java_frame()) { 2969 // Traverse the execution stack to call f() on the methods in the stack 2970 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2971 fst.current()->metadata_do(f); 2972 } 2973 } else if (is_Compiler_thread()) { 2974 // need to walk ciMetadata in current compile tasks to keep alive. 2975 CompilerThread* ct = (CompilerThread*)this; 2976 if (ct->env() != NULL) { 2977 ct->env()->metadata_do(f); 2978 } 2979 CompileTask* task = ct->task(); 2980 if (task != NULL) { 2981 task->metadata_do(f); 2982 } 2983 } 2984 } 2985 2986 // Printing 2987 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2988 switch (_thread_state) { 2989 case _thread_uninitialized: return "_thread_uninitialized"; 2990 case _thread_new: return "_thread_new"; 2991 case _thread_new_trans: return "_thread_new_trans"; 2992 case _thread_in_native: return "_thread_in_native"; 2993 case _thread_in_native_trans: return "_thread_in_native_trans"; 2994 case _thread_in_vm: return "_thread_in_vm"; 2995 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2996 case _thread_in_Java: return "_thread_in_Java"; 2997 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2998 case _thread_blocked: return "_thread_blocked"; 2999 case _thread_blocked_trans: return "_thread_blocked_trans"; 3000 default: return "unknown thread state"; 3001 } 3002 } 3003 3004 #ifndef PRODUCT 3005 void JavaThread::print_thread_state_on(outputStream *st) const { 3006 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 3007 }; 3008 void JavaThread::print_thread_state() const { 3009 print_thread_state_on(tty); 3010 } 3011 #endif // PRODUCT 3012 3013 // Called by Threads::print() for VM_PrintThreads operation 3014 void JavaThread::print_on(outputStream *st, bool print_extended_info) const { 3015 st->print_raw("\""); 3016 st->print_raw(get_thread_name()); 3017 st->print_raw("\" "); 3018 oop thread_oop = threadObj(); 3019 if (thread_oop != NULL) { 3020 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop)); 3021 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 3022 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 3023 } 3024 Thread::print_on(st, print_extended_info); 3025 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 3026 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 3027 if (thread_oop != NULL) { 3028 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 3029 } 3030 #ifndef PRODUCT 3031 _safepoint_state->print_on(st); 3032 #endif // PRODUCT 3033 if (is_Compiler_thread()) { 3034 CompileTask *task = ((CompilerThread*)this)->task(); 3035 if (task != NULL) { 3036 st->print(" Compiling: "); 3037 task->print(st, NULL, true, false); 3038 } else { 3039 st->print(" No compile task"); 3040 } 3041 st->cr(); 3042 } 3043 } 3044 3045 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const { 3046 st->print("%s", get_thread_name_string(buf, buflen)); 3047 } 3048 3049 // Called by fatal error handler. The difference between this and 3050 // JavaThread::print() is that we can't grab lock or allocate memory. 3051 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 3052 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 3053 oop thread_obj = threadObj(); 3054 if (thread_obj != NULL) { 3055 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 3056 } 3057 st->print(" ["); 3058 st->print("%s", _get_thread_state_name(_thread_state)); 3059 if (osthread()) { 3060 st->print(", id=%d", osthread()->thread_id()); 3061 } 3062 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 3063 p2i(stack_end()), p2i(stack_base())); 3064 st->print("]"); 3065 3066 ThreadsSMRSupport::print_info_on(this, st); 3067 return; 3068 } 3069 3070 // Verification 3071 3072 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 3073 3074 void JavaThread::verify() { 3075 // Verify oops in the thread. 3076 oops_do(&VerifyOopClosure::verify_oop, NULL); 3077 3078 // Verify the stack frames. 3079 frames_do(frame_verify); 3080 } 3081 3082 // CR 6300358 (sub-CR 2137150) 3083 // Most callers of this method assume that it can't return NULL but a 3084 // thread may not have a name whilst it is in the process of attaching to 3085 // the VM - see CR 6412693, and there are places where a JavaThread can be 3086 // seen prior to having it's threadObj set (eg JNI attaching threads and 3087 // if vm exit occurs during initialization). These cases can all be accounted 3088 // for such that this method never returns NULL. 3089 const char* JavaThread::get_thread_name() const { 3090 #ifdef ASSERT 3091 // early safepoints can hit while current thread does not yet have TLS 3092 if (!SafepointSynchronize::is_at_safepoint()) { 3093 Thread *cur = Thread::current(); 3094 if (!(cur->is_Java_thread() && cur == this)) { 3095 // Current JavaThreads are allowed to get their own name without 3096 // the Threads_lock. 3097 assert_locked_or_safepoint(Threads_lock); 3098 } 3099 } 3100 #endif // ASSERT 3101 return get_thread_name_string(); 3102 } 3103 3104 // Returns a non-NULL representation of this thread's name, or a suitable 3105 // descriptive string if there is no set name 3106 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 3107 const char* name_str; 3108 oop thread_obj = threadObj(); 3109 if (thread_obj != NULL) { 3110 oop name = java_lang_Thread::name(thread_obj); 3111 if (name != NULL) { 3112 if (buf == NULL) { 3113 name_str = java_lang_String::as_utf8_string(name); 3114 } else { 3115 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 3116 } 3117 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 3118 name_str = "<no-name - thread is attaching>"; 3119 } else { 3120 name_str = Thread::name(); 3121 } 3122 } else { 3123 name_str = Thread::name(); 3124 } 3125 assert(name_str != NULL, "unexpected NULL thread name"); 3126 return name_str; 3127 } 3128 3129 3130 const char* JavaThread::get_threadgroup_name() const { 3131 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 3132 oop thread_obj = threadObj(); 3133 if (thread_obj != NULL) { 3134 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 3135 if (thread_group != NULL) { 3136 // ThreadGroup.name can be null 3137 return java_lang_ThreadGroup::name(thread_group); 3138 } 3139 } 3140 return NULL; 3141 } 3142 3143 const char* JavaThread::get_parent_name() const { 3144 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 3145 oop thread_obj = threadObj(); 3146 if (thread_obj != NULL) { 3147 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 3148 if (thread_group != NULL) { 3149 oop parent = java_lang_ThreadGroup::parent(thread_group); 3150 if (parent != NULL) { 3151 // ThreadGroup.name can be null 3152 return java_lang_ThreadGroup::name(parent); 3153 } 3154 } 3155 } 3156 return NULL; 3157 } 3158 3159 ThreadPriority JavaThread::java_priority() const { 3160 oop thr_oop = threadObj(); 3161 if (thr_oop == NULL) return NormPriority; // Bootstrapping 3162 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 3163 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 3164 return priority; 3165 } 3166 3167 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 3168 3169 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3170 // Link Java Thread object <-> C++ Thread 3171 3172 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3173 // and put it into a new Handle. The Handle "thread_oop" can then 3174 // be used to pass the C++ thread object to other methods. 3175 3176 // Set the Java level thread object (jthread) field of the 3177 // new thread (a JavaThread *) to C++ thread object using the 3178 // "thread_oop" handle. 3179 3180 // Set the thread field (a JavaThread *) of the 3181 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3182 3183 Handle thread_oop(Thread::current(), 3184 JNIHandles::resolve_non_null(jni_thread)); 3185 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3186 "must be initialized"); 3187 set_threadObj(thread_oop()); 3188 java_lang_Thread::set_thread(thread_oop(), this); 3189 3190 if (prio == NoPriority) { 3191 prio = java_lang_Thread::priority(thread_oop()); 3192 assert(prio != NoPriority, "A valid priority should be present"); 3193 } 3194 3195 // Push the Java priority down to the native thread; needs Threads_lock 3196 Thread::set_priority(this, prio); 3197 3198 // Add the new thread to the Threads list and set it in motion. 3199 // We must have threads lock in order to call Threads::add. 3200 // It is crucial that we do not block before the thread is 3201 // added to the Threads list for if a GC happens, then the java_thread oop 3202 // will not be visited by GC. 3203 Threads::add(this); 3204 } 3205 3206 oop JavaThread::current_park_blocker() { 3207 // Support for JSR-166 locks 3208 oop thread_oop = threadObj(); 3209 if (thread_oop != NULL && 3210 JDK_Version::current().supports_thread_park_blocker()) { 3211 return java_lang_Thread::park_blocker(thread_oop); 3212 } 3213 return NULL; 3214 } 3215 3216 3217 void JavaThread::print_stack_on(outputStream* st) { 3218 if (!has_last_Java_frame()) return; 3219 ResourceMark rm; 3220 HandleMark hm; 3221 3222 RegisterMap reg_map(this); 3223 vframe* start_vf = last_java_vframe(®_map); 3224 int count = 0; 3225 for (vframe* f = start_vf; f != NULL; f = f->sender()) { 3226 if (f->is_java_frame()) { 3227 javaVFrame* jvf = javaVFrame::cast(f); 3228 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3229 3230 // Print out lock information 3231 if (JavaMonitorsInStackTrace) { 3232 jvf->print_lock_info_on(st, count); 3233 } 3234 } else { 3235 // Ignore non-Java frames 3236 } 3237 3238 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0 3239 count++; 3240 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return; 3241 } 3242 } 3243 3244 3245 // JVMTI PopFrame support 3246 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3247 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3248 if (in_bytes(size_in_bytes) != 0) { 3249 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3250 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3251 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3252 } 3253 } 3254 3255 void* JavaThread::popframe_preserved_args() { 3256 return _popframe_preserved_args; 3257 } 3258 3259 ByteSize JavaThread::popframe_preserved_args_size() { 3260 return in_ByteSize(_popframe_preserved_args_size); 3261 } 3262 3263 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3264 int sz = in_bytes(popframe_preserved_args_size()); 3265 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3266 return in_WordSize(sz / wordSize); 3267 } 3268 3269 void JavaThread::popframe_free_preserved_args() { 3270 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3271 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3272 _popframe_preserved_args = NULL; 3273 _popframe_preserved_args_size = 0; 3274 } 3275 3276 #ifndef PRODUCT 3277 3278 void JavaThread::trace_frames() { 3279 tty->print_cr("[Describe stack]"); 3280 int frame_no = 1; 3281 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3282 tty->print(" %d. ", frame_no++); 3283 fst.current()->print_value_on(tty, this); 3284 tty->cr(); 3285 } 3286 } 3287 3288 class PrintAndVerifyOopClosure: public OopClosure { 3289 protected: 3290 template <class T> inline void do_oop_work(T* p) { 3291 oop obj = RawAccess<>::oop_load(p); 3292 if (obj == NULL) return; 3293 tty->print(INTPTR_FORMAT ": ", p2i(p)); 3294 if (oopDesc::is_oop_or_null(obj)) { 3295 if (obj->is_objArray()) { 3296 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); 3297 } else { 3298 obj->print(); 3299 } 3300 } else { 3301 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); 3302 } 3303 tty->cr(); 3304 } 3305 public: 3306 virtual void do_oop(oop* p) { do_oop_work(p); } 3307 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3308 }; 3309 3310 3311 static void oops_print(frame* f, const RegisterMap *map) { 3312 PrintAndVerifyOopClosure print; 3313 f->print_value(); 3314 f->oops_do(&print, NULL, (RegisterMap*)map); 3315 } 3316 3317 // Print our all the locations that contain oops and whether they are 3318 // valid or not. This useful when trying to find the oldest frame 3319 // where an oop has gone bad since the frame walk is from youngest to 3320 // oldest. 3321 void JavaThread::trace_oops() { 3322 tty->print_cr("[Trace oops]"); 3323 frames_do(oops_print); 3324 } 3325 3326 3327 #ifdef ASSERT 3328 // Print or validate the layout of stack frames 3329 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3330 ResourceMark rm; 3331 PRESERVE_EXCEPTION_MARK; 3332 FrameValues values; 3333 int frame_no = 0; 3334 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3335 fst.current()->describe(values, ++frame_no); 3336 if (depth == frame_no) break; 3337 } 3338 if (validate_only) { 3339 values.validate(); 3340 } else { 3341 tty->print_cr("[Describe stack layout]"); 3342 values.print(this); 3343 } 3344 } 3345 #endif 3346 3347 void JavaThread::trace_stack_from(vframe* start_vf) { 3348 ResourceMark rm; 3349 int vframe_no = 1; 3350 for (vframe* f = start_vf; f; f = f->sender()) { 3351 if (f->is_java_frame()) { 3352 javaVFrame::cast(f)->print_activation(vframe_no++); 3353 } else { 3354 f->print(); 3355 } 3356 if (vframe_no > StackPrintLimit) { 3357 tty->print_cr("...<more frames>..."); 3358 return; 3359 } 3360 } 3361 } 3362 3363 3364 void JavaThread::trace_stack() { 3365 if (!has_last_Java_frame()) return; 3366 ResourceMark rm; 3367 HandleMark hm; 3368 RegisterMap reg_map(this); 3369 trace_stack_from(last_java_vframe(®_map)); 3370 } 3371 3372 3373 #endif // PRODUCT 3374 3375 3376 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3377 assert(reg_map != NULL, "a map must be given"); 3378 frame f = last_frame(); 3379 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3380 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3381 } 3382 return NULL; 3383 } 3384 3385 3386 Klass* JavaThread::security_get_caller_class(int depth) { 3387 vframeStream vfst(this); 3388 vfst.security_get_caller_frame(depth); 3389 if (!vfst.at_end()) { 3390 return vfst.method()->method_holder(); 3391 } 3392 return NULL; 3393 } 3394 3395 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3396 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3397 CompileBroker::compiler_thread_loop(); 3398 } 3399 3400 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3401 NMethodSweeper::sweeper_loop(); 3402 } 3403 3404 // Create a CompilerThread 3405 CompilerThread::CompilerThread(CompileQueue* queue, 3406 CompilerCounters* counters) 3407 : JavaThread(&compiler_thread_entry) { 3408 _env = NULL; 3409 _log = NULL; 3410 _task = NULL; 3411 _queue = queue; 3412 _counters = counters; 3413 _buffer_blob = NULL; 3414 _compiler = NULL; 3415 3416 // Compiler uses resource area for compilation, let's bias it to mtCompiler 3417 resource_area()->bias_to(mtCompiler); 3418 3419 #ifndef PRODUCT 3420 _ideal_graph_printer = NULL; 3421 #endif 3422 } 3423 3424 CompilerThread::~CompilerThread() { 3425 // Delete objects which were allocated on heap. 3426 delete _counters; 3427 } 3428 3429 bool CompilerThread::can_call_java() const { 3430 return _compiler != NULL && _compiler->is_jvmci(); 3431 } 3432 3433 // Create sweeper thread 3434 CodeCacheSweeperThread::CodeCacheSweeperThread() 3435 : JavaThread(&sweeper_thread_entry) { 3436 _scanned_compiled_method = NULL; 3437 } 3438 3439 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 3440 JavaThread::oops_do(f, cf); 3441 if (_scanned_compiled_method != NULL && cf != NULL) { 3442 // Safepoints can occur when the sweeper is scanning an nmethod so 3443 // process it here to make sure it isn't unloaded in the middle of 3444 // a scan. 3445 cf->do_code_blob(_scanned_compiled_method); 3446 } 3447 } 3448 3449 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) { 3450 JavaThread::nmethods_do(cf); 3451 if (_scanned_compiled_method != NULL && cf != NULL) { 3452 // Safepoints can occur when the sweeper is scanning an nmethod so 3453 // process it here to make sure it isn't unloaded in the middle of 3454 // a scan. 3455 cf->do_code_blob(_scanned_compiled_method); 3456 } 3457 } 3458 3459 3460 // ======= Threads ======== 3461 3462 // The Threads class links together all active threads, and provides 3463 // operations over all threads. It is protected by the Threads_lock, 3464 // which is also used in other global contexts like safepointing. 3465 // ThreadsListHandles are used to safely perform operations on one 3466 // or more threads without the risk of the thread exiting during the 3467 // operation. 3468 // 3469 // Note: The Threads_lock is currently more widely used than we 3470 // would like. We are actively migrating Threads_lock uses to other 3471 // mechanisms in order to reduce Threads_lock contention. 3472 3473 JavaThread* Threads::_thread_list = NULL; 3474 int Threads::_number_of_threads = 0; 3475 int Threads::_number_of_non_daemon_threads = 0; 3476 int Threads::_return_code = 0; 3477 uintx Threads::_thread_claim_token = 1; // Never zero. 3478 size_t JavaThread::_stack_size_at_create = 0; 3479 3480 #ifdef ASSERT 3481 bool Threads::_vm_complete = false; 3482 #endif 3483 3484 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) { 3485 Prefetch::read((void*)addr, prefetch_interval); 3486 return *addr; 3487 } 3488 3489 // Possibly the ugliest for loop the world has seen. C++ does not allow 3490 // multiple types in the declaration section of the for loop. In this case 3491 // we are only dealing with pointers and hence can cast them. It looks ugly 3492 // but macros are ugly and therefore it's fine to make things absurdly ugly. 3493 #define DO_JAVA_THREADS(LIST, X) \ 3494 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \ 3495 *MACRO_list = (JavaThread*)(LIST), \ 3496 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \ 3497 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \ 3498 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \ 3499 MACRO_current_p != MACRO_end; \ 3500 MACRO_current_p++, \ 3501 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval)) 3502 3503 // All JavaThreads 3504 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X) 3505 3506 // All NonJavaThreads (i.e., every non-JavaThread in the system). 3507 void Threads::non_java_threads_do(ThreadClosure* tc) { 3508 NoSafepointVerifier nsv(!SafepointSynchronize::is_at_safepoint(), false); 3509 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) { 3510 tc->do_thread(njti.current()); 3511 } 3512 } 3513 3514 // All JavaThreads 3515 void Threads::java_threads_do(ThreadClosure* tc) { 3516 assert_locked_or_safepoint(Threads_lock); 3517 // ALL_JAVA_THREADS iterates through all JavaThreads. 3518 ALL_JAVA_THREADS(p) { 3519 tc->do_thread(p); 3520 } 3521 } 3522 3523 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) { 3524 assert_locked_or_safepoint(Threads_lock); 3525 java_threads_do(tc); 3526 tc->do_thread(VMThread::vm_thread()); 3527 } 3528 3529 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system). 3530 void Threads::threads_do(ThreadClosure* tc) { 3531 assert_locked_or_safepoint(Threads_lock); 3532 java_threads_do(tc); 3533 non_java_threads_do(tc); 3534 } 3535 3536 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) { 3537 uintx claim_token = Threads::thread_claim_token(); 3538 ALL_JAVA_THREADS(p) { 3539 if (p->claim_threads_do(is_par, claim_token)) { 3540 tc->do_thread(p); 3541 } 3542 } 3543 VMThread* vmt = VMThread::vm_thread(); 3544 if (vmt->claim_threads_do(is_par, claim_token)) { 3545 tc->do_thread(vmt); 3546 } 3547 } 3548 3549 // The system initialization in the library has three phases. 3550 // 3551 // Phase 1: java.lang.System class initialization 3552 // java.lang.System is a primordial class loaded and initialized 3553 // by the VM early during startup. java.lang.System.<clinit> 3554 // only does registerNatives and keeps the rest of the class 3555 // initialization work later until thread initialization completes. 3556 // 3557 // System.initPhase1 initializes the system properties, the static 3558 // fields in, out, and err. Set up java signal handlers, OS-specific 3559 // system settings, and thread group of the main thread. 3560 static void call_initPhase1(TRAPS) { 3561 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3562 JavaValue result(T_VOID); 3563 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(), 3564 vmSymbols::void_method_signature(), CHECK); 3565 } 3566 3567 // Phase 2. Module system initialization 3568 // This will initialize the module system. Only java.base classes 3569 // can be loaded until phase 2 completes. 3570 // 3571 // Call System.initPhase2 after the compiler initialization and jsr292 3572 // classes get initialized because module initialization runs a lot of java 3573 // code, that for performance reasons, should be compiled. Also, this will 3574 // enable the startup code to use lambda and other language features in this 3575 // phase and onward. 3576 // 3577 // After phase 2, The VM will begin search classes from -Xbootclasspath/a. 3578 static void call_initPhase2(TRAPS) { 3579 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime)); 3580 3581 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3582 3583 JavaValue result(T_INT); 3584 JavaCallArguments args; 3585 args.push_int(DisplayVMOutputToStderr); 3586 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown 3587 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(), 3588 vmSymbols::boolean_boolean_int_signature(), &args, CHECK); 3589 if (result.get_jint() != JNI_OK) { 3590 vm_exit_during_initialization(); // no message or exception 3591 } 3592 3593 universe_post_module_init(); 3594 } 3595 3596 // Phase 3. final setup - set security manager, system class loader and TCCL 3597 // 3598 // This will instantiate and set the security manager, set the system class 3599 // loader as well as the thread context class loader. The security manager 3600 // and system class loader may be a custom class loaded from -Xbootclasspath/a, 3601 // other modules or the application's classpath. 3602 static void call_initPhase3(TRAPS) { 3603 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3604 JavaValue result(T_VOID); 3605 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(), 3606 vmSymbols::void_method_signature(), CHECK); 3607 } 3608 3609 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3610 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime)); 3611 3612 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3613 create_vm_init_libraries(); 3614 } 3615 3616 initialize_class(vmSymbols::java_lang_String(), CHECK); 3617 3618 // Inject CompactStrings value after the static initializers for String ran. 3619 java_lang_String::set_compact_strings(CompactStrings); 3620 3621 // Initialize java_lang.System (needed before creating the thread) 3622 initialize_class(vmSymbols::java_lang_System(), CHECK); 3623 // The VM creates & returns objects of this class. Make sure it's initialized. 3624 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3625 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3626 Handle thread_group = create_initial_thread_group(CHECK); 3627 Universe::set_main_thread_group(thread_group()); 3628 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3629 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3630 main_thread->set_threadObj(thread_object); 3631 3632 // Set thread status to running since main thread has 3633 // been started and running. 3634 java_lang_Thread::set_thread_status(thread_object, 3635 java_lang_Thread::RUNNABLE); 3636 3637 // The VM creates objects of this class. 3638 initialize_class(vmSymbols::java_lang_Module(), CHECK); 3639 3640 #ifdef ASSERT 3641 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass(); 3642 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized"); 3643 #endif 3644 3645 // initialize the hardware-specific constants needed by Unsafe 3646 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK); 3647 jdk_internal_misc_UnsafeConstants::set_unsafe_constants(); 3648 3649 // The VM preresolves methods to these classes. Make sure that they get initialized 3650 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3651 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3652 3653 // Phase 1 of the system initialization in the library, java.lang.System class initialization 3654 call_initPhase1(CHECK); 3655 3656 // get the Java runtime name after java.lang.System is initialized 3657 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3658 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3659 3660 // an instance of OutOfMemory exception has been allocated earlier 3661 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3662 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3663 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3664 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3665 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3666 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3667 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3668 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3669 } 3670 3671 void Threads::initialize_jsr292_core_classes(TRAPS) { 3672 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime)); 3673 3674 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3675 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK); 3676 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3677 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3678 } 3679 3680 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3681 extern void JDK_Version_init(); 3682 3683 // Preinitialize version info. 3684 VM_Version::early_initialize(); 3685 3686 // Check version 3687 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3688 3689 // Initialize library-based TLS 3690 ThreadLocalStorage::init(); 3691 3692 // Initialize the output stream module 3693 ostream_init(); 3694 3695 // Process java launcher properties. 3696 Arguments::process_sun_java_launcher_properties(args); 3697 3698 // Initialize the os module 3699 os::init(); 3700 3701 // Record VM creation timing statistics 3702 TraceVmCreationTime create_vm_timer; 3703 create_vm_timer.start(); 3704 3705 // Initialize system properties. 3706 Arguments::init_system_properties(); 3707 3708 // So that JDK version can be used as a discriminator when parsing arguments 3709 JDK_Version_init(); 3710 3711 // Update/Initialize System properties after JDK version number is known 3712 Arguments::init_version_specific_system_properties(); 3713 3714 // Make sure to initialize log configuration *before* parsing arguments 3715 LogConfiguration::initialize(create_vm_timer.begin_time()); 3716 3717 // Parse arguments 3718 // Note: this internally calls os::init_container_support() 3719 jint parse_result = Arguments::parse(args); 3720 if (parse_result != JNI_OK) return parse_result; 3721 3722 os::init_before_ergo(); 3723 3724 jint ergo_result = Arguments::apply_ergo(); 3725 if (ergo_result != JNI_OK) return ergo_result; 3726 3727 // Final check of all ranges after ergonomics which may change values. 3728 if (!JVMFlagRangeList::check_ranges()) { 3729 return JNI_EINVAL; 3730 } 3731 3732 // Final check of all 'AfterErgo' constraints after ergonomics which may change values. 3733 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo); 3734 if (!constraint_result) { 3735 return JNI_EINVAL; 3736 } 3737 3738 JVMFlagWriteableList::mark_startup(); 3739 3740 if (PauseAtStartup) { 3741 os::pause(); 3742 } 3743 3744 HOTSPOT_VM_INIT_BEGIN(); 3745 3746 // Timing (must come after argument parsing) 3747 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime)); 3748 3749 // Initialize the os module after parsing the args 3750 jint os_init_2_result = os::init_2(); 3751 if (os_init_2_result != JNI_OK) return os_init_2_result; 3752 3753 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT 3754 // Initialize assert poison page mechanism. 3755 if (ShowRegistersOnAssert) { 3756 initialize_assert_poison(); 3757 } 3758 #endif // CAN_SHOW_REGISTERS_ON_ASSERT 3759 3760 SafepointMechanism::initialize(); 3761 3762 jint adjust_after_os_result = Arguments::adjust_after_os(); 3763 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3764 3765 // Initialize output stream logging 3766 ostream_init_log(); 3767 3768 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3769 // Must be before create_vm_init_agents() 3770 if (Arguments::init_libraries_at_startup()) { 3771 convert_vm_init_libraries_to_agents(); 3772 } 3773 3774 // Launch -agentlib/-agentpath and converted -Xrun agents 3775 if (Arguments::init_agents_at_startup()) { 3776 create_vm_init_agents(); 3777 } 3778 3779 // Initialize Threads state 3780 _thread_list = NULL; 3781 _number_of_threads = 0; 3782 _number_of_non_daemon_threads = 0; 3783 3784 // Initialize global data structures and create system classes in heap 3785 vm_init_globals(); 3786 3787 #if INCLUDE_JVMCI 3788 if (JVMCICounterSize > 0) { 3789 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 3790 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize); 3791 } else { 3792 JavaThread::_jvmci_old_thread_counters = NULL; 3793 } 3794 #endif // INCLUDE_JVMCI 3795 3796 // Attach the main thread to this os thread 3797 JavaThread* main_thread = new JavaThread(); 3798 main_thread->set_thread_state(_thread_in_vm); 3799 main_thread->initialize_thread_current(); 3800 // must do this before set_active_handles 3801 main_thread->record_stack_base_and_size(); 3802 main_thread->register_thread_stack_with_NMT(); 3803 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3804 3805 if (!main_thread->set_as_starting_thread()) { 3806 vm_shutdown_during_initialization( 3807 "Failed necessary internal allocation. Out of swap space"); 3808 main_thread->smr_delete(); 3809 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3810 return JNI_ENOMEM; 3811 } 3812 3813 // Enable guard page *after* os::create_main_thread(), otherwise it would 3814 // crash Linux VM, see notes in os_linux.cpp. 3815 main_thread->create_stack_guard_pages(); 3816 3817 // Initialize Java-Level synchronization subsystem 3818 ObjectMonitor::Initialize(); 3819 3820 // Initialize global modules 3821 jint status = init_globals(); 3822 if (status != JNI_OK) { 3823 main_thread->smr_delete(); 3824 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3825 return status; 3826 } 3827 3828 JFR_ONLY(Jfr::on_vm_init();) 3829 3830 // Should be done after the heap is fully created 3831 main_thread->cache_global_variables(); 3832 3833 HandleMark hm; 3834 3835 { MutexLocker mu(Threads_lock); 3836 Threads::add(main_thread); 3837 } 3838 3839 // Any JVMTI raw monitors entered in onload will transition into 3840 // real raw monitor. VM is setup enough here for raw monitor enter. 3841 JvmtiExport::transition_pending_onload_raw_monitors(); 3842 3843 // Create the VMThread 3844 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime)); 3845 3846 VMThread::create(); 3847 Thread* vmthread = VMThread::vm_thread(); 3848 3849 if (!os::create_thread(vmthread, os::vm_thread)) { 3850 vm_exit_during_initialization("Cannot create VM thread. " 3851 "Out of system resources."); 3852 } 3853 3854 // Wait for the VM thread to become ready, and VMThread::run to initialize 3855 // Monitors can have spurious returns, must always check another state flag 3856 { 3857 MutexLocker ml(Notify_lock); 3858 os::start_thread(vmthread); 3859 while (vmthread->active_handles() == NULL) { 3860 Notify_lock->wait(); 3861 } 3862 } 3863 } 3864 3865 assert(Universe::is_fully_initialized(), "not initialized"); 3866 if (VerifyDuringStartup) { 3867 // Make sure we're starting with a clean slate. 3868 VM_Verify verify_op; 3869 VMThread::execute(&verify_op); 3870 } 3871 3872 // We need this to update the java.vm.info property in case any flags used 3873 // to initially define it have been changed. This is needed for both CDS and 3874 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info 3875 // is initially computed. See Abstract_VM_Version::vm_info_string(). 3876 // This update must happen before we initialize the java classes, but 3877 // after any initialization logic that might modify the flags. 3878 Arguments::update_vm_info_property(VM_Version::vm_info_string()); 3879 3880 Thread* THREAD = Thread::current(); 3881 3882 // Always call even when there are not JVMTI environments yet, since environments 3883 // may be attached late and JVMTI must track phases of VM execution 3884 JvmtiExport::enter_early_start_phase(); 3885 3886 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3887 JvmtiExport::post_early_vm_start(); 3888 3889 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3890 3891 quicken_jni_functions(); 3892 3893 // No more stub generation allowed after that point. 3894 StubCodeDesc::freeze(); 3895 3896 // Set flag that basic initialization has completed. Used by exceptions and various 3897 // debug stuff, that does not work until all basic classes have been initialized. 3898 set_init_completed(); 3899 3900 LogConfiguration::post_initialize(); 3901 Metaspace::post_initialize(); 3902 3903 HOTSPOT_VM_INIT_END(); 3904 3905 // record VM initialization completion time 3906 #if INCLUDE_MANAGEMENT 3907 Management::record_vm_init_completed(); 3908 #endif // INCLUDE_MANAGEMENT 3909 3910 // Signal Dispatcher needs to be started before VMInit event is posted 3911 os::initialize_jdk_signal_support(CHECK_JNI_ERR); 3912 3913 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3914 if (!DisableAttachMechanism) { 3915 AttachListener::vm_start(); 3916 if (StartAttachListener || AttachListener::init_at_startup()) { 3917 AttachListener::init(); 3918 } 3919 } 3920 3921 // Launch -Xrun agents 3922 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3923 // back-end can launch with -Xdebug -Xrunjdwp. 3924 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3925 create_vm_init_libraries(); 3926 } 3927 3928 if (CleanChunkPoolAsync) { 3929 Chunk::start_chunk_pool_cleaner_task(); 3930 } 3931 3932 // initialize compiler(s) 3933 #if defined(COMPILER1) || COMPILER2_OR_JVMCI 3934 #if INCLUDE_JVMCI 3935 bool force_JVMCI_intialization = false; 3936 if (EnableJVMCI) { 3937 // Initialize JVMCI eagerly when it is explicitly requested. 3938 // Or when JVMCIPrintProperties is enabled. 3939 // The JVMCI Java initialization code will read this flag and 3940 // do the printing if it's set. 3941 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties; 3942 3943 if (!force_JVMCI_intialization) { 3944 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking 3945 // compilations via JVMCI will not actually block until JVMCI is initialized. 3946 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation); 3947 } 3948 } 3949 #endif 3950 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR); 3951 // Postpone completion of compiler initialization to after JVMCI 3952 // is initialized to avoid timeouts of blocking compilations. 3953 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) { 3954 CompileBroker::compilation_init_phase2(); 3955 } 3956 #endif 3957 3958 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3959 // It is done after compilers are initialized, because otherwise compilations of 3960 // signature polymorphic MH intrinsics can be missed 3961 // (see SystemDictionary::find_method_handle_intrinsic). 3962 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3963 3964 // This will initialize the module system. Only java.base classes can be 3965 // loaded until phase 2 completes 3966 call_initPhase2(CHECK_JNI_ERR); 3967 3968 // Always call even when there are not JVMTI environments yet, since environments 3969 // may be attached late and JVMTI must track phases of VM execution 3970 JvmtiExport::enter_start_phase(); 3971 3972 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3973 JvmtiExport::post_vm_start(); 3974 3975 // Final system initialization including security manager and system class loader 3976 call_initPhase3(CHECK_JNI_ERR); 3977 3978 // cache the system and platform class loaders 3979 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR); 3980 3981 #if INCLUDE_CDS 3982 if (DumpSharedSpaces) { 3983 // capture the module path info from the ModuleEntryTable 3984 ClassLoader::initialize_module_path(THREAD); 3985 } 3986 #endif 3987 3988 #if INCLUDE_JVMCI 3989 if (force_JVMCI_intialization) { 3990 JVMCIRuntime::force_initialization(CHECK_JNI_ERR); 3991 CompileBroker::compilation_init_phase2(); 3992 } 3993 #endif 3994 3995 // Always call even when there are not JVMTI environments yet, since environments 3996 // may be attached late and JVMTI must track phases of VM execution 3997 JvmtiExport::enter_live_phase(); 3998 3999 // Make perfmemory accessible 4000 PerfMemory::set_accessible(true); 4001 4002 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 4003 JvmtiExport::post_vm_initialized(); 4004 4005 JFR_ONLY(Jfr::on_vm_start();) 4006 4007 #if INCLUDE_MANAGEMENT 4008 Management::initialize(THREAD); 4009 4010 if (HAS_PENDING_EXCEPTION) { 4011 // management agent fails to start possibly due to 4012 // configuration problem and is responsible for printing 4013 // stack trace if appropriate. Simply exit VM. 4014 vm_exit(1); 4015 } 4016 #endif // INCLUDE_MANAGEMENT 4017 4018 if (MemProfiling) MemProfiler::engage(); 4019 StatSampler::engage(); 4020 if (CheckJNICalls) JniPeriodicChecker::engage(); 4021 4022 BiasedLocking::init(); 4023 4024 #if INCLUDE_RTM_OPT 4025 RTMLockingCounters::init(); 4026 #endif 4027 4028 if (JDK_Version::current().post_vm_init_hook_enabled()) { 4029 call_postVMInitHook(THREAD); 4030 // The Java side of PostVMInitHook.run must deal with all 4031 // exceptions and provide means of diagnosis. 4032 if (HAS_PENDING_EXCEPTION) { 4033 CLEAR_PENDING_EXCEPTION; 4034 } 4035 } 4036 4037 { 4038 MutexLocker ml(PeriodicTask_lock); 4039 // Make sure the WatcherThread can be started by WatcherThread::start() 4040 // or by dynamic enrollment. 4041 WatcherThread::make_startable(); 4042 // Start up the WatcherThread if there are any periodic tasks 4043 // NOTE: All PeriodicTasks should be registered by now. If they 4044 // aren't, late joiners might appear to start slowly (we might 4045 // take a while to process their first tick). 4046 if (PeriodicTask::num_tasks() > 0) { 4047 WatcherThread::start(); 4048 } 4049 } 4050 4051 create_vm_timer.end(); 4052 #ifdef ASSERT 4053 _vm_complete = true; 4054 #endif 4055 4056 if (DumpSharedSpaces) { 4057 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 4058 ShouldNotReachHere(); 4059 } 4060 4061 return JNI_OK; 4062 } 4063 4064 // type for the Agent_OnLoad and JVM_OnLoad entry points 4065 extern "C" { 4066 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 4067 } 4068 // Find a command line agent library and return its entry point for 4069 // -agentlib: -agentpath: -Xrun 4070 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 4071 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 4072 const char *on_load_symbols[], 4073 size_t num_symbol_entries) { 4074 OnLoadEntry_t on_load_entry = NULL; 4075 void *library = NULL; 4076 4077 if (!agent->valid()) { 4078 char buffer[JVM_MAXPATHLEN]; 4079 char ebuf[1024] = ""; 4080 const char *name = agent->name(); 4081 const char *msg = "Could not find agent library "; 4082 4083 // First check to see if agent is statically linked into executable 4084 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 4085 library = agent->os_lib(); 4086 } else if (agent->is_absolute_path()) { 4087 library = os::dll_load(name, ebuf, sizeof ebuf); 4088 if (library == NULL) { 4089 const char *sub_msg = " in absolute path, with error: "; 4090 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 4091 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 4092 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 4093 // If we can't find the agent, exit. 4094 vm_exit_during_initialization(buf, NULL); 4095 FREE_C_HEAP_ARRAY(char, buf); 4096 } 4097 } else { 4098 // Try to load the agent from the standard dll directory 4099 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(), 4100 name)) { 4101 library = os::dll_load(buffer, ebuf, sizeof ebuf); 4102 } 4103 if (library == NULL) { // Try the library path directory. 4104 if (os::dll_build_name(buffer, sizeof(buffer), name)) { 4105 library = os::dll_load(buffer, ebuf, sizeof ebuf); 4106 } 4107 if (library == NULL) { 4108 const char *sub_msg = " on the library path, with error: "; 4109 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image."; 4110 4111 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + 4112 strlen(ebuf) + strlen(sub_msg2) + 1; 4113 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 4114 if (!agent->is_instrument_lib()) { 4115 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 4116 } else { 4117 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2); 4118 } 4119 // If we can't find the agent, exit. 4120 vm_exit_during_initialization(buf, NULL); 4121 FREE_C_HEAP_ARRAY(char, buf); 4122 } 4123 } 4124 } 4125 agent->set_os_lib(library); 4126 agent->set_valid(); 4127 } 4128 4129 // Find the OnLoad function. 4130 on_load_entry = 4131 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 4132 false, 4133 on_load_symbols, 4134 num_symbol_entries)); 4135 return on_load_entry; 4136 } 4137 4138 // Find the JVM_OnLoad entry point 4139 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 4140 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 4141 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 4142 } 4143 4144 // Find the Agent_OnLoad entry point 4145 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 4146 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 4147 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 4148 } 4149 4150 // For backwards compatibility with -Xrun 4151 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 4152 // treated like -agentpath: 4153 // Must be called before agent libraries are created 4154 void Threads::convert_vm_init_libraries_to_agents() { 4155 AgentLibrary* agent; 4156 AgentLibrary* next; 4157 4158 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 4159 next = agent->next(); // cache the next agent now as this agent may get moved off this list 4160 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 4161 4162 // If there is an JVM_OnLoad function it will get called later, 4163 // otherwise see if there is an Agent_OnLoad 4164 if (on_load_entry == NULL) { 4165 on_load_entry = lookup_agent_on_load(agent); 4166 if (on_load_entry != NULL) { 4167 // switch it to the agent list -- so that Agent_OnLoad will be called, 4168 // JVM_OnLoad won't be attempted and Agent_OnUnload will 4169 Arguments::convert_library_to_agent(agent); 4170 } else { 4171 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 4172 } 4173 } 4174 } 4175 } 4176 4177 // Create agents for -agentlib: -agentpath: and converted -Xrun 4178 // Invokes Agent_OnLoad 4179 // Called very early -- before JavaThreads exist 4180 void Threads::create_vm_init_agents() { 4181 extern struct JavaVM_ main_vm; 4182 AgentLibrary* agent; 4183 4184 JvmtiExport::enter_onload_phase(); 4185 4186 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 4187 // CDS dumping does not support native JVMTI agent. 4188 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified. 4189 if (DumpSharedSpaces) { 4190 if(!agent->is_instrument_lib()) { 4191 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name()); 4192 } else if (!AllowArchivingWithJavaAgent) { 4193 vm_exit_during_cds_dumping( 4194 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping"); 4195 } 4196 } 4197 4198 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 4199 4200 if (on_load_entry != NULL) { 4201 // Invoke the Agent_OnLoad function 4202 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 4203 if (err != JNI_OK) { 4204 vm_exit_during_initialization("agent library failed to init", agent->name()); 4205 } 4206 } else { 4207 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 4208 } 4209 } 4210 4211 JvmtiExport::enter_primordial_phase(); 4212 } 4213 4214 extern "C" { 4215 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 4216 } 4217 4218 void Threads::shutdown_vm_agents() { 4219 // Send any Agent_OnUnload notifications 4220 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 4221 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 4222 extern struct JavaVM_ main_vm; 4223 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 4224 4225 // Find the Agent_OnUnload function. 4226 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 4227 os::find_agent_function(agent, 4228 false, 4229 on_unload_symbols, 4230 num_symbol_entries)); 4231 4232 // Invoke the Agent_OnUnload function 4233 if (unload_entry != NULL) { 4234 JavaThread* thread = JavaThread::current(); 4235 ThreadToNativeFromVM ttn(thread); 4236 HandleMark hm(thread); 4237 (*unload_entry)(&main_vm); 4238 } 4239 } 4240 } 4241 4242 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 4243 // Invokes JVM_OnLoad 4244 void Threads::create_vm_init_libraries() { 4245 extern struct JavaVM_ main_vm; 4246 AgentLibrary* agent; 4247 4248 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 4249 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 4250 4251 if (on_load_entry != NULL) { 4252 // Invoke the JVM_OnLoad function 4253 JavaThread* thread = JavaThread::current(); 4254 ThreadToNativeFromVM ttn(thread); 4255 HandleMark hm(thread); 4256 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 4257 if (err != JNI_OK) { 4258 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 4259 } 4260 } else { 4261 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 4262 } 4263 } 4264 } 4265 4266 4267 // Last thread running calls java.lang.Shutdown.shutdown() 4268 void JavaThread::invoke_shutdown_hooks() { 4269 HandleMark hm(this); 4270 4271 // We could get here with a pending exception, if so clear it now. 4272 if (this->has_pending_exception()) { 4273 this->clear_pending_exception(); 4274 } 4275 4276 EXCEPTION_MARK; 4277 Klass* shutdown_klass = 4278 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 4279 THREAD); 4280 if (shutdown_klass != NULL) { 4281 // SystemDictionary::resolve_or_null will return null if there was 4282 // an exception. If we cannot load the Shutdown class, just don't 4283 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 4284 // won't be run. Note that if a shutdown hook was registered, 4285 // the Shutdown class would have already been loaded 4286 // (Runtime.addShutdownHook will load it). 4287 JavaValue result(T_VOID); 4288 JavaCalls::call_static(&result, 4289 shutdown_klass, 4290 vmSymbols::shutdown_method_name(), 4291 vmSymbols::void_method_signature(), 4292 THREAD); 4293 } 4294 CLEAR_PENDING_EXCEPTION; 4295 } 4296 4297 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 4298 // the program falls off the end of main(). Another VM exit path is through 4299 // vm_exit() when the program calls System.exit() to return a value or when 4300 // there is a serious error in VM. The two shutdown paths are not exactly 4301 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 4302 // and VM_Exit op at VM level. 4303 // 4304 // Shutdown sequence: 4305 // + Shutdown native memory tracking if it is on 4306 // + Wait until we are the last non-daemon thread to execute 4307 // <-- every thing is still working at this moment --> 4308 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 4309 // shutdown hooks 4310 // + Call before_exit(), prepare for VM exit 4311 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 4312 // currently the only user of this mechanism is File.deleteOnExit()) 4313 // > stop StatSampler, watcher thread, CMS threads, 4314 // post thread end and vm death events to JVMTI, 4315 // stop signal thread 4316 // + Call JavaThread::exit(), it will: 4317 // > release JNI handle blocks, remove stack guard pages 4318 // > remove this thread from Threads list 4319 // <-- no more Java code from this thread after this point --> 4320 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 4321 // the compiler threads at safepoint 4322 // <-- do not use anything that could get blocked by Safepoint --> 4323 // + Disable tracing at JNI/JVM barriers 4324 // + Set _vm_exited flag for threads that are still running native code 4325 // + Call exit_globals() 4326 // > deletes tty 4327 // > deletes PerfMemory resources 4328 // + Delete this thread 4329 // + Return to caller 4330 4331 bool Threads::destroy_vm() { 4332 JavaThread* thread = JavaThread::current(); 4333 4334 #ifdef ASSERT 4335 _vm_complete = false; 4336 #endif 4337 // Wait until we are the last non-daemon thread to execute 4338 { MutexLocker nu(Threads_lock); 4339 while (Threads::number_of_non_daemon_threads() > 1) 4340 // This wait should make safepoint checks, wait without a timeout, 4341 // and wait as a suspend-equivalent condition. 4342 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 4343 Mutex::_as_suspend_equivalent_flag); 4344 } 4345 4346 EventShutdown e; 4347 if (e.should_commit()) { 4348 e.set_reason("No remaining non-daemon Java threads"); 4349 e.commit(); 4350 } 4351 4352 // Hang forever on exit if we are reporting an error. 4353 if (ShowMessageBoxOnError && VMError::is_error_reported()) { 4354 os::infinite_sleep(); 4355 } 4356 os::wait_for_keypress_at_exit(); 4357 4358 // run Java level shutdown hooks 4359 thread->invoke_shutdown_hooks(); 4360 4361 before_exit(thread); 4362 4363 thread->exit(true); 4364 4365 // Stop VM thread. 4366 { 4367 // 4945125 The vm thread comes to a safepoint during exit. 4368 // GC vm_operations can get caught at the safepoint, and the 4369 // heap is unparseable if they are caught. Grab the Heap_lock 4370 // to prevent this. The GC vm_operations will not be able to 4371 // queue until after the vm thread is dead. After this point, 4372 // we'll never emerge out of the safepoint before the VM exits. 4373 4374 MutexLockerEx ml(Heap_lock, Mutex::_no_safepoint_check_flag); 4375 4376 VMThread::wait_for_vm_thread_exit(); 4377 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4378 VMThread::destroy(); 4379 } 4380 4381 // Now, all Java threads are gone except daemon threads. Daemon threads 4382 // running Java code or in VM are stopped by the Safepoint. However, 4383 // daemon threads executing native code are still running. But they 4384 // will be stopped at native=>Java/VM barriers. Note that we can't 4385 // simply kill or suspend them, as it is inherently deadlock-prone. 4386 4387 VM_Exit::set_vm_exited(); 4388 4389 // Clean up ideal graph printers after the VMThread has started 4390 // the final safepoint which will block all the Compiler threads. 4391 // Note that this Thread has already logically exited so the 4392 // clean_up() function's use of a JavaThreadIteratorWithHandle 4393 // would be a problem except set_vm_exited() has remembered the 4394 // shutdown thread which is granted a policy exception. 4395 #if defined(COMPILER2) && !defined(PRODUCT) 4396 IdealGraphPrinter::clean_up(); 4397 #endif 4398 4399 notify_vm_shutdown(); 4400 4401 // exit_globals() will delete tty 4402 exit_globals(); 4403 4404 // We are after VM_Exit::set_vm_exited() so we can't call 4405 // thread->smr_delete() or we will block on the Threads_lock. 4406 // Deleting the shutdown thread here is safe because another 4407 // JavaThread cannot have an active ThreadsListHandle for 4408 // this JavaThread. 4409 delete thread; 4410 4411 #if INCLUDE_JVMCI 4412 if (JVMCICounterSize > 0) { 4413 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters); 4414 } 4415 #endif 4416 4417 LogConfiguration::finalize(); 4418 4419 return true; 4420 } 4421 4422 4423 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4424 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4425 return is_supported_jni_version(version); 4426 } 4427 4428 4429 jboolean Threads::is_supported_jni_version(jint version) { 4430 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4431 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4432 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4433 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4434 if (version == JNI_VERSION_9) return JNI_TRUE; 4435 if (version == JNI_VERSION_10) return JNI_TRUE; 4436 return JNI_FALSE; 4437 } 4438 4439 4440 void Threads::add(JavaThread* p, bool force_daemon) { 4441 // The threads lock must be owned at this point 4442 assert(Threads_lock->owned_by_self(), "must have threads lock"); 4443 4444 BarrierSet::barrier_set()->on_thread_attach(p); 4445 4446 p->set_next(_thread_list); 4447 _thread_list = p; 4448 4449 // Once a JavaThread is added to the Threads list, smr_delete() has 4450 // to be used to delete it. Otherwise we can just delete it directly. 4451 p->set_on_thread_list(); 4452 4453 _number_of_threads++; 4454 oop threadObj = p->threadObj(); 4455 bool daemon = true; 4456 // Bootstrapping problem: threadObj can be null for initial 4457 // JavaThread (or for threads attached via JNI) 4458 if ((!force_daemon) && !is_daemon((threadObj))) { 4459 _number_of_non_daemon_threads++; 4460 daemon = false; 4461 } 4462 4463 ThreadService::add_thread(p, daemon); 4464 4465 // Maintain fast thread list 4466 ThreadsSMRSupport::add_thread(p); 4467 4468 // Possible GC point. 4469 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p)); 4470 } 4471 4472 void Threads::remove(JavaThread* p, bool is_daemon) { 4473 4474 // Reclaim the ObjectMonitors from the omInUseList and omFreeList of the moribund thread. 4475 ObjectSynchronizer::omFlush(p); 4476 4477 // Extra scope needed for Thread_lock, so we can check 4478 // that we do not remove thread without safepoint code notice 4479 { MutexLocker ml(Threads_lock); 4480 4481 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present"); 4482 4483 // Maintain fast thread list 4484 ThreadsSMRSupport::remove_thread(p); 4485 4486 JavaThread* current = _thread_list; 4487 JavaThread* prev = NULL; 4488 4489 while (current != p) { 4490 prev = current; 4491 current = current->next(); 4492 } 4493 4494 if (prev) { 4495 prev->set_next(current->next()); 4496 } else { 4497 _thread_list = p->next(); 4498 } 4499 4500 _number_of_threads--; 4501 if (!is_daemon) { 4502 _number_of_non_daemon_threads--; 4503 4504 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4505 // on destroy_vm will wake up. 4506 if (number_of_non_daemon_threads() == 1) { 4507 Threads_lock->notify_all(); 4508 } 4509 } 4510 ThreadService::remove_thread(p, is_daemon); 4511 4512 // Make sure that safepoint code disregard this thread. This is needed since 4513 // the thread might mess around with locks after this point. This can cause it 4514 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4515 // of this thread since it is removed from the queue. 4516 p->set_terminated_value(); 4517 } // unlock Threads_lock 4518 4519 // Since Events::log uses a lock, we grab it outside the Threads_lock 4520 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p)); 4521 } 4522 4523 // Operations on the Threads list for GC. These are not explicitly locked, 4524 // but the garbage collector must provide a safe context for them to run. 4525 // In particular, these things should never be called when the Threads_lock 4526 // is held by some other thread. (Note: the Safepoint abstraction also 4527 // uses the Threads_lock to guarantee this property. It also makes sure that 4528 // all threads gets blocked when exiting or starting). 4529 4530 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) { 4531 ALL_JAVA_THREADS(p) { 4532 p->oops_do(f, cf); 4533 } 4534 VMThread::vm_thread()->oops_do(f, cf); 4535 } 4536 4537 void Threads::change_thread_claim_token() { 4538 if (++_thread_claim_token == 0) { 4539 // On overflow of the token counter, there is a risk of future 4540 // collisions between a new global token value and a stale token 4541 // for a thread, because not all iterations visit all threads. 4542 // (Though it's pretty much a theoretical concern for non-trivial 4543 // token counter sizes.) To deal with the possibility, reset all 4544 // the thread tokens to zero on global token overflow. 4545 struct ResetClaims : public ThreadClosure { 4546 virtual void do_thread(Thread* t) { 4547 t->claim_threads_do(false, 0); 4548 } 4549 } reset_claims; 4550 Threads::threads_do(&reset_claims); 4551 // On overflow, update the global token to non-zero, to 4552 // avoid the special "never claimed" initial thread value. 4553 _thread_claim_token = 1; 4554 } 4555 } 4556 4557 #ifdef ASSERT 4558 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) { 4559 const uintx token = t->threads_do_token(); 4560 assert(token == expected, 4561 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != " 4562 UINTX_FORMAT, kind, p2i(t), token, expected); 4563 } 4564 4565 void Threads::assert_all_threads_claimed() { 4566 ALL_JAVA_THREADS(p) { 4567 assert_thread_claimed("Thread", p, _thread_claim_token); 4568 } 4569 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token); 4570 } 4571 #endif // ASSERT 4572 4573 class ParallelOopsDoThreadClosure : public ThreadClosure { 4574 private: 4575 OopClosure* _f; 4576 CodeBlobClosure* _cf; 4577 public: 4578 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {} 4579 void do_thread(Thread* t) { 4580 t->oops_do(_f, _cf); 4581 } 4582 }; 4583 4584 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) { 4585 ParallelOopsDoThreadClosure tc(f, cf); 4586 possibly_parallel_threads_do(is_par, &tc); 4587 } 4588 4589 void Threads::nmethods_do(CodeBlobClosure* cf) { 4590 ALL_JAVA_THREADS(p) { 4591 // This is used by the code cache sweeper to mark nmethods that are active 4592 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid 4593 // marking CodeCacheSweeperThread::_scanned_compiled_method as active. 4594 if(!p->is_Code_cache_sweeper_thread()) { 4595 p->nmethods_do(cf); 4596 } 4597 } 4598 } 4599 4600 void Threads::metadata_do(MetadataClosure* f) { 4601 ALL_JAVA_THREADS(p) { 4602 p->metadata_do(f); 4603 } 4604 } 4605 4606 class ThreadHandlesClosure : public ThreadClosure { 4607 void (*_f)(Metadata*); 4608 public: 4609 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4610 virtual void do_thread(Thread* thread) { 4611 thread->metadata_handles_do(_f); 4612 } 4613 }; 4614 4615 void Threads::metadata_handles_do(void f(Metadata*)) { 4616 // Only walk the Handles in Thread. 4617 ThreadHandlesClosure handles_closure(f); 4618 threads_do(&handles_closure); 4619 } 4620 4621 void Threads::deoptimized_wrt_marked_nmethods() { 4622 ALL_JAVA_THREADS(p) { 4623 p->deoptimized_wrt_marked_nmethods(); 4624 } 4625 } 4626 4627 4628 // Get count Java threads that are waiting to enter the specified monitor. 4629 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list, 4630 int count, 4631 address monitor) { 4632 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4633 4634 int i = 0; 4635 DO_JAVA_THREADS(t_list, p) { 4636 if (!p->can_call_java()) continue; 4637 4638 address pending = (address)p->current_pending_monitor(); 4639 if (pending == monitor) { // found a match 4640 if (i < count) result->append(p); // save the first count matches 4641 i++; 4642 } 4643 } 4644 4645 return result; 4646 } 4647 4648 4649 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list, 4650 address owner) { 4651 // NULL owner means not locked so we can skip the search 4652 if (owner == NULL) return NULL; 4653 4654 DO_JAVA_THREADS(t_list, p) { 4655 // first, see if owner is the address of a Java thread 4656 if (owner == (address)p) return p; 4657 } 4658 4659 // Cannot assert on lack of success here since this function may be 4660 // used by code that is trying to report useful problem information 4661 // like deadlock detection. 4662 if (UseHeavyMonitors) return NULL; 4663 4664 // If we didn't find a matching Java thread and we didn't force use of 4665 // heavyweight monitors, then the owner is the stack address of the 4666 // Lock Word in the owning Java thread's stack. 4667 // 4668 JavaThread* the_owner = NULL; 4669 DO_JAVA_THREADS(t_list, q) { 4670 if (q->is_lock_owned(owner)) { 4671 the_owner = q; 4672 break; 4673 } 4674 } 4675 4676 // cannot assert on lack of success here; see above comment 4677 return the_owner; 4678 } 4679 4680 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4681 void Threads::print_on(outputStream* st, bool print_stacks, 4682 bool internal_format, bool print_concurrent_locks, 4683 bool print_extended_info) { 4684 char buf[32]; 4685 st->print_raw_cr(os::local_time_string(buf, sizeof(buf))); 4686 4687 st->print_cr("Full thread dump %s (%s %s):", 4688 VM_Version::vm_name(), 4689 VM_Version::vm_release(), 4690 VM_Version::vm_info_string()); 4691 st->cr(); 4692 4693 #if INCLUDE_SERVICES 4694 // Dump concurrent locks 4695 ConcurrentLocksDump concurrent_locks; 4696 if (print_concurrent_locks) { 4697 concurrent_locks.dump_at_safepoint(); 4698 } 4699 #endif // INCLUDE_SERVICES 4700 4701 ThreadsSMRSupport::print_info_on(st); 4702 st->cr(); 4703 4704 ALL_JAVA_THREADS(p) { 4705 ResourceMark rm; 4706 p->print_on(st, print_extended_info); 4707 if (print_stacks) { 4708 if (internal_format) { 4709 p->trace_stack(); 4710 } else { 4711 p->print_stack_on(st); 4712 } 4713 } 4714 st->cr(); 4715 #if INCLUDE_SERVICES 4716 if (print_concurrent_locks) { 4717 concurrent_locks.print_locks_on(p, st); 4718 } 4719 #endif // INCLUDE_SERVICES 4720 } 4721 4722 VMThread::vm_thread()->print_on(st); 4723 st->cr(); 4724 Universe::heap()->print_gc_threads_on(st); 4725 WatcherThread* wt = WatcherThread::watcher_thread(); 4726 if (wt != NULL) { 4727 wt->print_on(st); 4728 st->cr(); 4729 } 4730 4731 st->flush(); 4732 } 4733 4734 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf, 4735 int buflen, bool* found_current) { 4736 if (this_thread != NULL) { 4737 bool is_current = (current == this_thread); 4738 *found_current = *found_current || is_current; 4739 st->print("%s", is_current ? "=>" : " "); 4740 4741 st->print(PTR_FORMAT, p2i(this_thread)); 4742 st->print(" "); 4743 this_thread->print_on_error(st, buf, buflen); 4744 st->cr(); 4745 } 4746 } 4747 4748 class PrintOnErrorClosure : public ThreadClosure { 4749 outputStream* _st; 4750 Thread* _current; 4751 char* _buf; 4752 int _buflen; 4753 bool* _found_current; 4754 public: 4755 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf, 4756 int buflen, bool* found_current) : 4757 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {} 4758 4759 virtual void do_thread(Thread* thread) { 4760 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current); 4761 } 4762 }; 4763 4764 // Threads::print_on_error() is called by fatal error handler. It's possible 4765 // that VM is not at safepoint and/or current thread is inside signal handler. 4766 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4767 // memory (even in resource area), it might deadlock the error handler. 4768 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4769 int buflen) { 4770 ThreadsSMRSupport::print_info_on(st); 4771 st->cr(); 4772 4773 bool found_current = false; 4774 st->print_cr("Java Threads: ( => current thread )"); 4775 ALL_JAVA_THREADS(thread) { 4776 print_on_error(thread, st, current, buf, buflen, &found_current); 4777 } 4778 st->cr(); 4779 4780 st->print_cr("Other Threads:"); 4781 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current); 4782 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current); 4783 4784 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current); 4785 Universe::heap()->gc_threads_do(&print_closure); 4786 4787 if (!found_current) { 4788 st->cr(); 4789 st->print("=>" PTR_FORMAT " (exited) ", p2i(current)); 4790 current->print_on_error(st, buf, buflen); 4791 st->cr(); 4792 } 4793 st->cr(); 4794 4795 st->print_cr("Threads with active compile tasks:"); 4796 print_threads_compiling(st, buf, buflen); 4797 } 4798 4799 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) { 4800 ALL_JAVA_THREADS(thread) { 4801 if (thread->is_Compiler_thread()) { 4802 CompilerThread* ct = (CompilerThread*) thread; 4803 4804 // Keep task in local variable for NULL check. 4805 // ct->_task might be set to NULL by concurring compiler thread 4806 // because it completed the compilation. The task is never freed, 4807 // though, just returned to a free list. 4808 CompileTask* task = ct->task(); 4809 if (task != NULL) { 4810 thread->print_name_on_error(st, buf, buflen); 4811 st->print(" "); 4812 task->print(st, NULL, short_form, true); 4813 } 4814 } 4815 } 4816 } 4817 4818 4819 // Internal SpinLock and Mutex 4820 // Based on ParkEvent 4821 4822 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4823 // 4824 // We employ SpinLocks _only for low-contention, fixed-length 4825 // short-duration critical sections where we're concerned 4826 // about native mutex_t or HotSpot Mutex:: latency. 4827 // The mux construct provides a spin-then-block mutual exclusion 4828 // mechanism. 4829 // 4830 // Testing has shown that contention on the ListLock guarding gFreeList 4831 // is common. If we implement ListLock as a simple SpinLock it's common 4832 // for the JVM to devolve to yielding with little progress. This is true 4833 // despite the fact that the critical sections protected by ListLock are 4834 // extremely short. 4835 // 4836 // TODO-FIXME: ListLock should be of type SpinLock. 4837 // We should make this a 1st-class type, integrated into the lock 4838 // hierarchy as leaf-locks. Critically, the SpinLock structure 4839 // should have sufficient padding to avoid false-sharing and excessive 4840 // cache-coherency traffic. 4841 4842 4843 typedef volatile int SpinLockT; 4844 4845 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4846 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4847 return; // normal fast-path return 4848 } 4849 4850 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4851 int ctr = 0; 4852 int Yields = 0; 4853 for (;;) { 4854 while (*adr != 0) { 4855 ++ctr; 4856 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4857 if (Yields > 5) { 4858 os::naked_short_sleep(1); 4859 } else { 4860 os::naked_yield(); 4861 ++Yields; 4862 } 4863 } else { 4864 SpinPause(); 4865 } 4866 } 4867 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4868 } 4869 } 4870 4871 void Thread::SpinRelease(volatile int * adr) { 4872 assert(*adr != 0, "invariant"); 4873 OrderAccess::fence(); // guarantee at least release consistency. 4874 // Roach-motel semantics. 4875 // It's safe if subsequent LDs and STs float "up" into the critical section, 4876 // but prior LDs and STs within the critical section can't be allowed 4877 // to reorder or float past the ST that releases the lock. 4878 // Loads and stores in the critical section - which appear in program 4879 // order before the store that releases the lock - must also appear 4880 // before the store that releases the lock in memory visibility order. 4881 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4882 // the ST of 0 into the lock-word which releases the lock, so fence 4883 // more than covers this on all platforms. 4884 *adr = 0; 4885 } 4886 4887 // muxAcquire and muxRelease: 4888 // 4889 // * muxAcquire and muxRelease support a single-word lock-word construct. 4890 // The LSB of the word is set IFF the lock is held. 4891 // The remainder of the word points to the head of a singly-linked list 4892 // of threads blocked on the lock. 4893 // 4894 // * The current implementation of muxAcquire-muxRelease uses its own 4895 // dedicated Thread._MuxEvent instance. If we're interested in 4896 // minimizing the peak number of extant ParkEvent instances then 4897 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4898 // as certain invariants were satisfied. Specifically, care would need 4899 // to be taken with regards to consuming unpark() "permits". 4900 // A safe rule of thumb is that a thread would never call muxAcquire() 4901 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4902 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4903 // consume an unpark() permit intended for monitorenter, for instance. 4904 // One way around this would be to widen the restricted-range semaphore 4905 // implemented in park(). Another alternative would be to provide 4906 // multiple instances of the PlatformEvent() for each thread. One 4907 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4908 // 4909 // * Usage: 4910 // -- Only as leaf locks 4911 // -- for short-term locking only as muxAcquire does not perform 4912 // thread state transitions. 4913 // 4914 // Alternatives: 4915 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4916 // but with parking or spin-then-park instead of pure spinning. 4917 // * Use Taura-Oyama-Yonenzawa locks. 4918 // * It's possible to construct a 1-0 lock if we encode the lockword as 4919 // (List,LockByte). Acquire will CAS the full lockword while Release 4920 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4921 // acquiring threads use timers (ParkTimed) to detect and recover from 4922 // the stranding window. Thread/Node structures must be aligned on 256-byte 4923 // boundaries by using placement-new. 4924 // * Augment MCS with advisory back-link fields maintained with CAS(). 4925 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4926 // The validity of the backlinks must be ratified before we trust the value. 4927 // If the backlinks are invalid the exiting thread must back-track through the 4928 // the forward links, which are always trustworthy. 4929 // * Add a successor indication. The LockWord is currently encoded as 4930 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4931 // to provide the usual futile-wakeup optimization. 4932 // See RTStt for details. 4933 // 4934 4935 4936 const intptr_t LOCKBIT = 1; 4937 4938 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4939 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0); 4940 if (w == 0) return; 4941 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 4942 return; 4943 } 4944 4945 ParkEvent * const Self = Thread::current()->_MuxEvent; 4946 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4947 for (;;) { 4948 int its = (os::is_MP() ? 100 : 0) + 1; 4949 4950 // Optional spin phase: spin-then-park strategy 4951 while (--its >= 0) { 4952 w = *Lock; 4953 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 4954 return; 4955 } 4956 } 4957 4958 Self->reset(); 4959 Self->OnList = intptr_t(Lock); 4960 // The following fence() isn't _strictly necessary as the subsequent 4961 // CAS() both serializes execution and ratifies the fetched *Lock value. 4962 OrderAccess::fence(); 4963 for (;;) { 4964 w = *Lock; 4965 if ((w & LOCKBIT) == 0) { 4966 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 4967 Self->OnList = 0; // hygiene - allows stronger asserts 4968 return; 4969 } 4970 continue; // Interference -- *Lock changed -- Just retry 4971 } 4972 assert(w & LOCKBIT, "invariant"); 4973 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4974 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4975 } 4976 4977 while (Self->OnList != 0) { 4978 Self->park(); 4979 } 4980 } 4981 } 4982 4983 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4984 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0); 4985 if (w == 0) return; 4986 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 4987 return; 4988 } 4989 4990 ParkEvent * ReleaseAfter = NULL; 4991 if (ev == NULL) { 4992 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4993 } 4994 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4995 for (;;) { 4996 guarantee(ev->OnList == 0, "invariant"); 4997 int its = (os::is_MP() ? 100 : 0) + 1; 4998 4999 // Optional spin phase: spin-then-park strategy 5000 while (--its >= 0) { 5001 w = *Lock; 5002 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 5003 if (ReleaseAfter != NULL) { 5004 ParkEvent::Release(ReleaseAfter); 5005 } 5006 return; 5007 } 5008 } 5009 5010 ev->reset(); 5011 ev->OnList = intptr_t(Lock); 5012 // The following fence() isn't _strictly necessary as the subsequent 5013 // CAS() both serializes execution and ratifies the fetched *Lock value. 5014 OrderAccess::fence(); 5015 for (;;) { 5016 w = *Lock; 5017 if ((w & LOCKBIT) == 0) { 5018 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 5019 ev->OnList = 0; 5020 // We call ::Release while holding the outer lock, thus 5021 // artificially lengthening the critical section. 5022 // Consider deferring the ::Release() until the subsequent unlock(), 5023 // after we've dropped the outer lock. 5024 if (ReleaseAfter != NULL) { 5025 ParkEvent::Release(ReleaseAfter); 5026 } 5027 return; 5028 } 5029 continue; // Interference -- *Lock changed -- Just retry 5030 } 5031 assert(w & LOCKBIT, "invariant"); 5032 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 5033 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 5034 } 5035 5036 while (ev->OnList != 0) { 5037 ev->park(); 5038 } 5039 } 5040 } 5041 5042 // Release() must extract a successor from the list and then wake that thread. 5043 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 5044 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 5045 // Release() would : 5046 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 5047 // (B) Extract a successor from the private list "in-hand" 5048 // (C) attempt to CAS() the residual back into *Lock over null. 5049 // If there were any newly arrived threads and the CAS() would fail. 5050 // In that case Release() would detach the RATs, re-merge the list in-hand 5051 // with the RATs and repeat as needed. Alternately, Release() might 5052 // detach and extract a successor, but then pass the residual list to the wakee. 5053 // The wakee would be responsible for reattaching and remerging before it 5054 // competed for the lock. 5055 // 5056 // Both "pop" and DMR are immune from ABA corruption -- there can be 5057 // multiple concurrent pushers, but only one popper or detacher. 5058 // This implementation pops from the head of the list. This is unfair, 5059 // but tends to provide excellent throughput as hot threads remain hot. 5060 // (We wake recently run threads first). 5061 // 5062 // All paths through muxRelease() will execute a CAS. 5063 // Release consistency -- We depend on the CAS in muxRelease() to provide full 5064 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 5065 // executed within the critical section are complete and globally visible before the 5066 // store (CAS) to the lock-word that releases the lock becomes globally visible. 5067 void Thread::muxRelease(volatile intptr_t * Lock) { 5068 for (;;) { 5069 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT); 5070 assert(w & LOCKBIT, "invariant"); 5071 if (w == LOCKBIT) return; 5072 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 5073 assert(List != NULL, "invariant"); 5074 assert(List->OnList == intptr_t(Lock), "invariant"); 5075 ParkEvent * const nxt = List->ListNext; 5076 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 5077 5078 // The following CAS() releases the lock and pops the head element. 5079 // The CAS() also ratifies the previously fetched lock-word value. 5080 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) { 5081 continue; 5082 } 5083 List->OnList = 0; 5084 OrderAccess::fence(); 5085 List->unpark(); 5086 return; 5087 } 5088 } 5089 5090 5091 void Threads::verify() { 5092 ALL_JAVA_THREADS(p) { 5093 p->verify(); 5094 } 5095 VMThread* thread = VMThread::vm_thread(); 5096 if (thread != NULL) thread->verify(); 5097 }