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 "aot/aotLoader.hpp" 28 #include "classfile/classLoader.hpp" 29 #include "classfile/javaClasses.hpp" 30 #include "classfile/moduleEntry.hpp" 31 #include "classfile/systemDictionary.hpp" 32 #include "classfile/vmSymbols.hpp" 33 #include "code/codeCache.hpp" 34 #include "code/scopeDesc.hpp" 35 #include "compiler/compileBroker.hpp" 36 #include "compiler/compileTask.hpp" 37 #include "gc/shared/barrierSet.hpp" 38 #include "gc/shared/gcId.hpp" 39 #include "gc/shared/gcLocker.inline.hpp" 40 #include "gc/shared/workgroup.hpp" 41 #include "interpreter/interpreter.hpp" 42 #include "interpreter/linkResolver.hpp" 43 #include "interpreter/oopMapCache.hpp" 44 #include "jfr/jfrEvents.hpp" 45 #include "jvmtifiles/jvmtiEnv.hpp" 46 #include "logging/log.hpp" 47 #include "logging/logConfiguration.hpp" 48 #include "logging/logStream.hpp" 49 #include "memory/allocation.inline.hpp" 50 #include "memory/metaspaceShared.hpp" 51 #include "memory/oopFactory.hpp" 52 #include "memory/resourceArea.hpp" 53 #include "memory/universe.hpp" 54 #include "oops/access.inline.hpp" 55 #include "oops/instanceKlass.hpp" 56 #include "oops/objArrayOop.hpp" 57 #include "oops/oop.inline.hpp" 58 #include "oops/symbol.hpp" 59 #include "oops/typeArrayOop.inline.hpp" 60 #include "oops/verifyOopClosure.hpp" 61 #include "prims/jvm_misc.hpp" 62 #include "prims/jvmtiExport.hpp" 63 #include "prims/jvmtiThreadState.hpp" 64 #include "runtime/arguments.hpp" 65 #include "runtime/atomic.hpp" 66 #include "runtime/biasedLocking.hpp" 67 #include "runtime/fieldDescriptor.inline.hpp" 68 #include "runtime/flags/jvmFlagConstraintList.hpp" 69 #include "runtime/flags/jvmFlagRangeList.hpp" 70 #include "runtime/flags/jvmFlagWriteableList.hpp" 71 #include "runtime/deoptimization.hpp" 72 #include "runtime/frame.inline.hpp" 73 #include "runtime/handles.inline.hpp" 74 #include "runtime/handshake.hpp" 75 #include "runtime/init.hpp" 76 #include "runtime/interfaceSupport.inline.hpp" 77 #include "runtime/java.hpp" 78 #include "runtime/javaCalls.hpp" 79 #include "runtime/jniHandles.inline.hpp" 80 #include "runtime/jniPeriodicChecker.hpp" 81 #include "runtime/memprofiler.hpp" 82 #include "runtime/mutexLocker.hpp" 83 #include "runtime/objectMonitor.hpp" 84 #include "runtime/orderAccess.hpp" 85 #include "runtime/osThread.hpp" 86 #include "runtime/prefetch.inline.hpp" 87 #include "runtime/safepoint.hpp" 88 #include "runtime/safepointMechanism.inline.hpp" 89 #include "runtime/safepointVerifiers.hpp" 90 #include "runtime/sharedRuntime.hpp" 91 #include "runtime/statSampler.hpp" 92 #include "runtime/stubRoutines.hpp" 93 #include "runtime/sweeper.hpp" 94 #include "runtime/task.hpp" 95 #include "runtime/thread.inline.hpp" 96 #include "runtime/threadCritical.hpp" 97 #include "runtime/threadSMR.inline.hpp" 98 #include "runtime/threadStatisticalInfo.hpp" 99 #include "runtime/timer.hpp" 100 #include "runtime/timerTrace.hpp" 101 #include "runtime/vframe.inline.hpp" 102 #include "runtime/vframeArray.hpp" 103 #include "runtime/vframe_hp.hpp" 104 #include "runtime/vmThread.hpp" 105 #include "runtime/vmOperations.hpp" 106 #include "runtime/vm_version.hpp" 107 #include "services/attachListener.hpp" 108 #include "services/management.hpp" 109 #include "services/memTracker.hpp" 110 #include "services/threadService.hpp" 111 #include "utilities/align.hpp" 112 #include "utilities/copy.hpp" 113 #include "utilities/defaultStream.hpp" 114 #include "utilities/dtrace.hpp" 115 #include "utilities/events.hpp" 116 #include "utilities/macros.hpp" 117 #include "utilities/preserveException.hpp" 118 #include "utilities/singleWriterSynchronizer.hpp" 119 #include "utilities/vmError.hpp" 120 #if INCLUDE_JVMCI 121 #include "jvmci/jvmci.hpp" 122 #include "jvmci/jvmciEnv.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; 269 270 #ifdef ASSERT 271 _visited_for_critical_count = false; 272 #endif 273 274 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, 275 Monitor::_safepoint_check_sometimes); 276 _suspend_flags = 0; 277 278 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 279 _hashStateX = os::random(); 280 _hashStateY = 842502087; 281 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 282 _hashStateW = 273326509; 283 284 _OnTrap = 0; 285 _Stalled = 0; 286 _TypeTag = 0x2BAD; 287 288 // Many of the following fields are effectively final - immutable 289 // Note that nascent threads can't use the Native Monitor-Mutex 290 // construct until the _MutexEvent is initialized ... 291 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 292 // we might instead use a stack of ParkEvents that we could provision on-demand. 293 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 294 // and ::Release() 295 _ParkEvent = ParkEvent::Allocate(this); 296 _SleepEvent = ParkEvent::Allocate(this); 297 _MuxEvent = ParkEvent::Allocate(this); 298 299 #ifdef CHECK_UNHANDLED_OOPS 300 if (CheckUnhandledOops) { 301 _unhandled_oops = new UnhandledOops(this); 302 } 303 #endif // CHECK_UNHANDLED_OOPS 304 #ifdef ASSERT 305 if (UseBiasedLocking) { 306 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 307 assert(this == _real_malloc_address || 308 this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment), 309 "bug in forced alignment of thread objects"); 310 } 311 #endif // ASSERT 312 313 // Notify the barrier set that a thread is being created. The initial 314 // thread is created before the barrier set is available. The call to 315 // BarrierSet::on_thread_create() for this thread is therefore deferred 316 // to BarrierSet::set_barrier_set(). 317 BarrierSet* const barrier_set = BarrierSet::barrier_set(); 318 if (barrier_set != NULL) { 319 barrier_set->on_thread_create(this); 320 } else { 321 // Only the main thread should be created before the barrier set 322 // and that happens just before Thread::current is set. No other thread 323 // can attach as the VM is not created yet, so they can't execute this code. 324 // If the main thread creates other threads before the barrier set that is an error. 325 assert(Thread::current_or_null() == NULL, "creating thread before barrier set"); 326 } 327 } 328 329 void Thread::initialize_thread_current() { 330 #ifndef USE_LIBRARY_BASED_TLS_ONLY 331 assert(_thr_current == NULL, "Thread::current already initialized"); 332 _thr_current = this; 333 #endif 334 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized"); 335 ThreadLocalStorage::set_thread(this); 336 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 337 } 338 339 void Thread::clear_thread_current() { 340 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 341 #ifndef USE_LIBRARY_BASED_TLS_ONLY 342 _thr_current = NULL; 343 #endif 344 ThreadLocalStorage::set_thread(NULL); 345 } 346 347 void Thread::record_stack_base_and_size() { 348 // Note: at this point, Thread object is not yet initialized. Do not rely on 349 // any members being initialized. Do not rely on Thread::current() being set. 350 // If possible, refrain from doing anything which may crash or assert since 351 // quite probably those crash dumps will be useless. 352 set_stack_base(os::current_stack_base()); 353 set_stack_size(os::current_stack_size()); 354 355 #ifdef SOLARIS 356 if (os::is_primordial_thread()) { 357 os::Solaris::correct_stack_boundaries_for_primordial_thread(this); 358 } 359 #endif 360 361 // Set stack limits after thread is initialized. 362 if (is_Java_thread()) { 363 ((JavaThread*) this)->set_stack_overflow_limit(); 364 ((JavaThread*) this)->set_reserved_stack_activation(stack_base()); 365 } 366 } 367 368 #if INCLUDE_NMT 369 void Thread::register_thread_stack_with_NMT() { 370 MemTracker::record_thread_stack(stack_end(), stack_size()); 371 } 372 #endif // INCLUDE_NMT 373 374 void Thread::call_run() { 375 DEBUG_ONLY(_run_state = CALL_RUN;) 376 377 // At this point, Thread object should be fully initialized and 378 // Thread::current() should be set. 379 380 assert(Thread::current_or_null() != NULL, "current thread is unset"); 381 assert(Thread::current_or_null() == this, "current thread is wrong"); 382 383 // Perform common initialization actions 384 385 register_thread_stack_with_NMT(); 386 387 JFR_ONLY(Jfr::on_thread_start(this);) 388 389 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: " 390 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).", 391 os::current_thread_id(), p2i(stack_base() - stack_size()), 392 p2i(stack_base()), stack_size()/1024); 393 394 // Perform <ChildClass> initialization actions 395 DEBUG_ONLY(_run_state = PRE_RUN;) 396 this->pre_run(); 397 398 // Invoke <ChildClass>::run() 399 DEBUG_ONLY(_run_state = RUN;) 400 this->run(); 401 // Returned from <ChildClass>::run(). Thread finished. 402 403 // Perform common tear-down actions 404 405 assert(Thread::current_or_null() != NULL, "current thread is unset"); 406 assert(Thread::current_or_null() == this, "current thread is wrong"); 407 408 // Perform <ChildClass> tear-down actions 409 DEBUG_ONLY(_run_state = POST_RUN;) 410 this->post_run(); 411 412 // Note: at this point the thread object may already have deleted itself, 413 // so from here on do not dereference *this*. Not all thread types currently 414 // delete themselves when they terminate. But no thread should ever be deleted 415 // asynchronously with respect to its termination - that is what _run_state can 416 // be used to check. 417 418 assert(Thread::current_or_null() == NULL, "current thread still present"); 419 } 420 421 Thread::~Thread() { 422 423 // Attached threads will remain in PRE_CALL_RUN, as will threads that don't actually 424 // get started due to errors etc. Any active thread should at least reach post_run 425 // before it is deleted (usually in post_run()). 426 assert(_run_state == PRE_CALL_RUN || 427 _run_state == POST_RUN, "Active Thread deleted before post_run(): " 428 "_run_state=%d", (int)_run_state); 429 430 // Notify the barrier set that a thread is being destroyed. Note that a barrier 431 // set might not be available if we encountered errors during bootstrapping. 432 BarrierSet* const barrier_set = BarrierSet::barrier_set(); 433 if (barrier_set != NULL) { 434 barrier_set->on_thread_destroy(this); 435 } 436 437 // stack_base can be NULL if the thread is never started or exited before 438 // record_stack_base_and_size called. Although, we would like to ensure 439 // that all started threads do call record_stack_base_and_size(), there is 440 // not proper way to enforce that. 441 #if INCLUDE_NMT 442 if (_stack_base != NULL) { 443 MemTracker::release_thread_stack(stack_end(), stack_size()); 444 #ifdef ASSERT 445 set_stack_base(NULL); 446 #endif 447 } 448 #endif // INCLUDE_NMT 449 450 // deallocate data structures 451 delete resource_area(); 452 // since the handle marks are using the handle area, we have to deallocated the root 453 // handle mark before deallocating the thread's handle area, 454 assert(last_handle_mark() != NULL, "check we have an element"); 455 delete last_handle_mark(); 456 assert(last_handle_mark() == NULL, "check we have reached the end"); 457 458 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 459 // We NULL out the fields for good hygiene. 460 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 461 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 462 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 463 464 delete handle_area(); 465 delete metadata_handles(); 466 467 // SR_handler uses this as a termination indicator - 468 // needs to happen before os::free_thread() 469 delete _SR_lock; 470 _SR_lock = NULL; 471 472 // osthread() can be NULL, if creation of thread failed. 473 if (osthread() != NULL) os::free_thread(osthread()); 474 475 // Clear Thread::current if thread is deleting itself and it has not 476 // already been done. This must be done before the memory is deallocated. 477 // Needed to ensure JNI correctly detects non-attached threads. 478 if (this == Thread::current_or_null()) { 479 Thread::clear_thread_current(); 480 } 481 482 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 483 } 484 485 #ifdef ASSERT 486 // A JavaThread is considered "dangling" if it is not the current 487 // thread, has been added the Threads list, the system is not at a 488 // safepoint and the Thread is not "protected". 489 // 490 void Thread::check_for_dangling_thread_pointer(Thread *thread) { 491 assert(!thread->is_Java_thread() || Thread::current() == thread || 492 !((JavaThread *) thread)->on_thread_list() || 493 SafepointSynchronize::is_at_safepoint() || 494 ThreadsSMRSupport::is_a_protected_JavaThread_with_lock((JavaThread *) thread), 495 "possibility of dangling Thread pointer"); 496 } 497 #endif 498 499 ThreadPriority Thread::get_priority(const Thread* const thread) { 500 ThreadPriority priority; 501 // Can return an error! 502 (void)os::get_priority(thread, priority); 503 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 504 return priority; 505 } 506 507 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 508 debug_only(check_for_dangling_thread_pointer(thread);) 509 // Can return an error! 510 (void)os::set_priority(thread, priority); 511 } 512 513 514 void Thread::start(Thread* thread) { 515 // Start is different from resume in that its safety is guaranteed by context or 516 // being called from a Java method synchronized on the Thread object. 517 if (!DisableStartThread) { 518 if (thread->is_Java_thread()) { 519 // Initialize the thread state to RUNNABLE before starting this thread. 520 // Can not set it after the thread started because we do not know the 521 // exact thread state at that time. It could be in MONITOR_WAIT or 522 // in SLEEPING or some other state. 523 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 524 java_lang_Thread::RUNNABLE); 525 } 526 os::start_thread(thread); 527 } 528 } 529 530 // Enqueue a VM_Operation to do the job for us - sometime later 531 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 532 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 533 VMThread::execute(vm_stop); 534 } 535 536 537 // Check if an external suspend request has completed (or has been 538 // cancelled). Returns true if the thread is externally suspended and 539 // false otherwise. 540 // 541 // The bits parameter returns information about the code path through 542 // the routine. Useful for debugging: 543 // 544 // set in is_ext_suspend_completed(): 545 // 0x00000001 - routine was entered 546 // 0x00000010 - routine return false at end 547 // 0x00000100 - thread exited (return false) 548 // 0x00000200 - suspend request cancelled (return false) 549 // 0x00000400 - thread suspended (return true) 550 // 0x00001000 - thread is in a suspend equivalent state (return true) 551 // 0x00002000 - thread is native and walkable (return true) 552 // 0x00004000 - thread is native_trans and walkable (needed retry) 553 // 554 // set in wait_for_ext_suspend_completion(): 555 // 0x00010000 - routine was entered 556 // 0x00020000 - suspend request cancelled before loop (return false) 557 // 0x00040000 - thread suspended before loop (return true) 558 // 0x00080000 - suspend request cancelled in loop (return false) 559 // 0x00100000 - thread suspended in loop (return true) 560 // 0x00200000 - suspend not completed during retry loop (return false) 561 562 // Helper class for tracing suspend wait debug bits. 563 // 564 // 0x00000100 indicates that the target thread exited before it could 565 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 566 // 0x00080000 each indicate a cancelled suspend request so they don't 567 // count as wait failures either. 568 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 569 570 class TraceSuspendDebugBits : public StackObj { 571 private: 572 JavaThread * jt; 573 bool is_wait; 574 bool called_by_wait; // meaningful when !is_wait 575 uint32_t * bits; 576 577 public: 578 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 579 uint32_t *_bits) { 580 jt = _jt; 581 is_wait = _is_wait; 582 called_by_wait = _called_by_wait; 583 bits = _bits; 584 } 585 586 ~TraceSuspendDebugBits() { 587 if (!is_wait) { 588 #if 1 589 // By default, don't trace bits for is_ext_suspend_completed() calls. 590 // That trace is very chatty. 591 return; 592 #else 593 if (!called_by_wait) { 594 // If tracing for is_ext_suspend_completed() is enabled, then only 595 // trace calls to it from wait_for_ext_suspend_completion() 596 return; 597 } 598 #endif 599 } 600 601 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 602 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 603 MutexLocker ml(Threads_lock); // needed for get_thread_name() 604 ResourceMark rm; 605 606 tty->print_cr( 607 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 608 jt->get_thread_name(), *bits); 609 610 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 611 } 612 } 613 } 614 }; 615 #undef DEBUG_FALSE_BITS 616 617 618 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 619 uint32_t *bits) { 620 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 621 622 bool did_trans_retry = false; // only do thread_in_native_trans retry once 623 bool do_trans_retry; // flag to force the retry 624 625 *bits |= 0x00000001; 626 627 do { 628 do_trans_retry = false; 629 630 if (is_exiting()) { 631 // Thread is in the process of exiting. This is always checked 632 // first to reduce the risk of dereferencing a freed JavaThread. 633 *bits |= 0x00000100; 634 return false; 635 } 636 637 if (!is_external_suspend()) { 638 // Suspend request is cancelled. This is always checked before 639 // is_ext_suspended() to reduce the risk of a rogue resume 640 // confusing the thread that made the suspend request. 641 *bits |= 0x00000200; 642 return false; 643 } 644 645 if (is_ext_suspended()) { 646 // thread is suspended 647 *bits |= 0x00000400; 648 return true; 649 } 650 651 // Now that we no longer do hard suspends of threads running 652 // native code, the target thread can be changing thread state 653 // while we are in this routine: 654 // 655 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 656 // 657 // We save a copy of the thread state as observed at this moment 658 // and make our decision about suspend completeness based on the 659 // copy. This closes the race where the thread state is seen as 660 // _thread_in_native_trans in the if-thread_blocked check, but is 661 // seen as _thread_blocked in if-thread_in_native_trans check. 662 JavaThreadState save_state = thread_state(); 663 664 if (save_state == _thread_blocked && is_suspend_equivalent()) { 665 // If the thread's state is _thread_blocked and this blocking 666 // condition is known to be equivalent to a suspend, then we can 667 // consider the thread to be externally suspended. This means that 668 // the code that sets _thread_blocked has been modified to do 669 // self-suspension if the blocking condition releases. We also 670 // used to check for CONDVAR_WAIT here, but that is now covered by 671 // the _thread_blocked with self-suspension check. 672 // 673 // Return true since we wouldn't be here unless there was still an 674 // external suspend request. 675 *bits |= 0x00001000; 676 return true; 677 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 678 // Threads running native code will self-suspend on native==>VM/Java 679 // transitions. If its stack is walkable (should always be the case 680 // unless this function is called before the actual java_suspend() 681 // call), then the wait is done. 682 *bits |= 0x00002000; 683 return true; 684 } else if (!called_by_wait && !did_trans_retry && 685 save_state == _thread_in_native_trans && 686 frame_anchor()->walkable()) { 687 // The thread is transitioning from thread_in_native to another 688 // thread state. check_safepoint_and_suspend_for_native_trans() 689 // will force the thread to self-suspend. If it hasn't gotten 690 // there yet we may have caught the thread in-between the native 691 // code check above and the self-suspend. Lucky us. If we were 692 // called by wait_for_ext_suspend_completion(), then it 693 // will be doing the retries so we don't have to. 694 // 695 // Since we use the saved thread state in the if-statement above, 696 // there is a chance that the thread has already transitioned to 697 // _thread_blocked by the time we get here. In that case, we will 698 // make a single unnecessary pass through the logic below. This 699 // doesn't hurt anything since we still do the trans retry. 700 701 *bits |= 0x00004000; 702 703 // Once the thread leaves thread_in_native_trans for another 704 // thread state, we break out of this retry loop. We shouldn't 705 // need this flag to prevent us from getting back here, but 706 // sometimes paranoia is good. 707 did_trans_retry = true; 708 709 // We wait for the thread to transition to a more usable state. 710 for (int i = 1; i <= SuspendRetryCount; i++) { 711 // We used to do an "os::yield_all(i)" call here with the intention 712 // that yielding would increase on each retry. However, the parameter 713 // is ignored on Linux which means the yield didn't scale up. Waiting 714 // on the SR_lock below provides a much more predictable scale up for 715 // the delay. It also provides a simple/direct point to check for any 716 // safepoint requests from the VMThread 717 718 // temporarily drops SR_lock while doing wait with safepoint check 719 // (if we're a JavaThread - the WatcherThread can also call this) 720 // and increase delay with each retry 721 if (Thread::current()->is_Java_thread()) { 722 SR_lock()->wait(i * delay); 723 } else { 724 SR_lock()->wait_without_safepoint_check(i * delay); 725 } 726 727 // check the actual thread state instead of what we saved above 728 if (thread_state() != _thread_in_native_trans) { 729 // the thread has transitioned to another thread state so 730 // try all the checks (except this one) one more time. 731 do_trans_retry = true; 732 break; 733 } 734 } // end retry loop 735 736 737 } 738 } while (do_trans_retry); 739 740 *bits |= 0x00000010; 741 return false; 742 } 743 744 // Wait for an external suspend request to complete (or be cancelled). 745 // Returns true if the thread is externally suspended and false otherwise. 746 // 747 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 748 uint32_t *bits) { 749 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 750 false /* !called_by_wait */, bits); 751 752 // local flag copies to minimize SR_lock hold time 753 bool is_suspended; 754 bool pending; 755 uint32_t reset_bits; 756 757 // set a marker so is_ext_suspend_completed() knows we are the caller 758 *bits |= 0x00010000; 759 760 // We use reset_bits to reinitialize the bits value at the top of 761 // each retry loop. This allows the caller to make use of any 762 // unused bits for their own marking purposes. 763 reset_bits = *bits; 764 765 { 766 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 767 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 768 delay, bits); 769 pending = is_external_suspend(); 770 } 771 // must release SR_lock to allow suspension to complete 772 773 if (!pending) { 774 // A cancelled suspend request is the only false return from 775 // is_ext_suspend_completed() that keeps us from entering the 776 // retry loop. 777 *bits |= 0x00020000; 778 return false; 779 } 780 781 if (is_suspended) { 782 *bits |= 0x00040000; 783 return true; 784 } 785 786 for (int i = 1; i <= retries; i++) { 787 *bits = reset_bits; // reinit to only track last retry 788 789 // We used to do an "os::yield_all(i)" call here with the intention 790 // that yielding would increase on each retry. However, the parameter 791 // is ignored on Linux which means the yield didn't scale up. Waiting 792 // on the SR_lock below provides a much more predictable scale up for 793 // the delay. It also provides a simple/direct point to check for any 794 // safepoint requests from the VMThread 795 796 { 797 Thread* t = Thread::current(); 798 MonitorLocker ml(SR_lock(), 799 t->is_Java_thread() ? Mutex::_safepoint_check_flag : Mutex::_no_safepoint_check_flag); 800 // wait with safepoint check (if we're a JavaThread - the WatcherThread 801 // can also call this) and increase delay with each retry 802 ml.wait(i * delay); 803 804 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 805 delay, bits); 806 807 // It is possible for the external suspend request to be cancelled 808 // (by a resume) before the actual suspend operation is completed. 809 // Refresh our local copy to see if we still need to wait. 810 pending = is_external_suspend(); 811 } 812 813 if (!pending) { 814 // A cancelled suspend request is the only false return from 815 // is_ext_suspend_completed() that keeps us from staying in the 816 // retry loop. 817 *bits |= 0x00080000; 818 return false; 819 } 820 821 if (is_suspended) { 822 *bits |= 0x00100000; 823 return true; 824 } 825 } // end retry loop 826 827 // thread did not suspend after all our retries 828 *bits |= 0x00200000; 829 return false; 830 } 831 832 // Called from API entry points which perform stack walking. If the 833 // associated JavaThread is the current thread, then wait_for_suspend 834 // is not used. Otherwise, it determines if we should wait for the 835 // "other" thread to complete external suspension. (NOTE: in future 836 // releases the suspension mechanism should be reimplemented so this 837 // is not necessary.) 838 // 839 bool 840 JavaThread::is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits) { 841 if (this != JavaThread::current()) { 842 // "other" threads require special handling. 843 if (wait_for_suspend) { 844 // We are allowed to wait for the external suspend to complete 845 // so give the other thread a chance to get suspended. 846 if (!wait_for_ext_suspend_completion(SuspendRetryCount, 847 SuspendRetryDelay, bits)) { 848 // Didn't make it so let the caller know. 849 return false; 850 } 851 } 852 // We aren't allowed to wait for the external suspend to complete 853 // so if the other thread isn't externally suspended we need to 854 // let the caller know. 855 else if (!is_ext_suspend_completed_with_lock(bits)) { 856 return false; 857 } 858 } 859 860 return true; 861 } 862 863 #ifndef PRODUCT 864 void JavaThread::record_jump(address target, address instr, const char* file, 865 int line) { 866 867 // This should not need to be atomic as the only way for simultaneous 868 // updates is via interrupts. Even then this should be rare or non-existent 869 // and we don't care that much anyway. 870 871 int index = _jmp_ring_index; 872 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 873 _jmp_ring[index]._target = (intptr_t) target; 874 _jmp_ring[index]._instruction = (intptr_t) instr; 875 _jmp_ring[index]._file = file; 876 _jmp_ring[index]._line = line; 877 } 878 #endif // PRODUCT 879 880 void Thread::interrupt(Thread* thread) { 881 debug_only(check_for_dangling_thread_pointer(thread);) 882 os::interrupt(thread); 883 } 884 885 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 886 debug_only(check_for_dangling_thread_pointer(thread);) 887 // Note: If clear_interrupted==false, this simply fetches and 888 // returns the value of the field osthread()->interrupted(). 889 return os::is_interrupted(thread, clear_interrupted); 890 } 891 892 893 // GC Support 894 bool Thread::claim_par_threads_do(uintx claim_token) { 895 uintx token = _threads_do_token; 896 if (token != claim_token) { 897 uintx res = Atomic::cmpxchg(claim_token, &_threads_do_token, token); 898 if (res == token) { 899 return true; 900 } 901 guarantee(res == claim_token, "invariant"); 902 } 903 return false; 904 } 905 906 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 907 active_handles()->oops_do(f); 908 // Do oop for ThreadShadow 909 f->do_oop((oop*)&_pending_exception); 910 handle_area()->oops_do(f); 911 912 // We scan thread local monitor lists here, and the remaining global 913 // monitors in ObjectSynchronizer::oops_do(). 914 ObjectSynchronizer::thread_local_used_oops_do(this, f); 915 } 916 917 void Thread::metadata_handles_do(void f(Metadata*)) { 918 // Only walk the Handles in Thread. 919 if (metadata_handles() != NULL) { 920 for (int i = 0; i< metadata_handles()->length(); i++) { 921 f(metadata_handles()->at(i)); 922 } 923 } 924 } 925 926 void Thread::print_on(outputStream* st, bool print_extended_info) const { 927 // get_priority assumes osthread initialized 928 if (osthread() != NULL) { 929 int os_prio; 930 if (os::get_native_priority(this, &os_prio) == OS_OK) { 931 st->print("os_prio=%d ", os_prio); 932 } 933 934 st->print("cpu=%.2fms ", 935 os::thread_cpu_time(const_cast<Thread*>(this), true) / 1000000.0 936 ); 937 st->print("elapsed=%.2fs ", 938 _statistical_info.getElapsedTime() / 1000.0 939 ); 940 if (is_Java_thread() && (PrintExtendedThreadInfo || print_extended_info)) { 941 size_t allocated_bytes = (size_t) const_cast<Thread*>(this)->cooked_allocated_bytes(); 942 st->print("allocated=" SIZE_FORMAT "%s ", 943 byte_size_in_proper_unit(allocated_bytes), 944 proper_unit_for_byte_size(allocated_bytes) 945 ); 946 st->print("defined_classes=" INT64_FORMAT " ", _statistical_info.getDefineClassCount()); 947 } 948 949 st->print("tid=" INTPTR_FORMAT " ", p2i(this)); 950 osthread()->print_on(st); 951 } 952 ThreadsSMRSupport::print_info_on(this, st); 953 st->print(" "); 954 debug_only(if (WizardMode) print_owned_locks_on(st);) 955 } 956 957 void Thread::print() const { print_on(tty); } 958 959 // Thread::print_on_error() is called by fatal error handler. Don't use 960 // any lock or allocate memory. 961 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 962 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates"); 963 964 if (is_VM_thread()) { st->print("VMThread"); } 965 else if (is_GC_task_thread()) { st->print("GCTaskThread"); } 966 else if (is_Watcher_thread()) { st->print("WatcherThread"); } 967 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); } 968 else { st->print("Thread"); } 969 970 if (is_Named_thread()) { 971 st->print(" \"%s\"", name()); 972 } 973 974 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 975 p2i(stack_end()), p2i(stack_base())); 976 977 if (osthread()) { 978 st->print(" [id=%d]", osthread()->thread_id()); 979 } 980 981 ThreadsSMRSupport::print_info_on(this, st); 982 } 983 984 void Thread::print_value_on(outputStream* st) const { 985 if (is_Named_thread()) { 986 st->print(" \"%s\" ", name()); 987 } 988 st->print(INTPTR_FORMAT, p2i(this)); // print address 989 } 990 991 #ifdef ASSERT 992 void Thread::print_owned_locks_on(outputStream* st) const { 993 Monitor *cur = _owned_locks; 994 if (cur == NULL) { 995 st->print(" (no locks) "); 996 } else { 997 st->print_cr(" Locks owned:"); 998 while (cur) { 999 cur->print_on(st); 1000 cur = cur->next(); 1001 } 1002 } 1003 } 1004 1005 static int ref_use_count = 0; 1006 1007 bool Thread::owns_locks_but_compiled_lock() const { 1008 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 1009 if (cur != Compile_lock) return true; 1010 } 1011 return false; 1012 } 1013 1014 1015 #endif 1016 1017 #ifndef PRODUCT 1018 1019 // The flag: potential_vm_operation notifies if this particular safepoint state could potentially 1020 // invoke the vm-thread (e.g., an oop allocation). In that case, we also have to make sure that 1021 // no locks which allow_vm_block's are held 1022 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 1023 // Check if current thread is allowed to block at a safepoint 1024 if (!(_allow_safepoint_count == 0)) { 1025 fatal("Possible safepoint reached by thread that does not allow it"); 1026 } 1027 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 1028 fatal("LEAF method calling lock?"); 1029 } 1030 1031 #ifdef ASSERT 1032 if (potential_vm_operation && is_Java_thread() 1033 && !Universe::is_bootstrapping()) { 1034 // Make sure we do not hold any locks that the VM thread also uses. 1035 // This could potentially lead to deadlocks 1036 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 1037 // Threads_lock is special, since the safepoint synchronization will not start before this is 1038 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 1039 // since it is used to transfer control between JavaThreads and the VMThread 1040 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 1041 if ((cur->allow_vm_block() && 1042 cur != Threads_lock && 1043 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 1044 cur != VMOperationRequest_lock && 1045 cur != VMOperationQueue_lock) || 1046 cur->rank() == Mutex::special) { 1047 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 1048 } 1049 } 1050 } 1051 1052 if (GCALotAtAllSafepoints) { 1053 // We could enter a safepoint here and thus have a gc 1054 InterfaceSupport::check_gc_alot(); 1055 } 1056 #endif 1057 } 1058 #endif 1059 1060 bool Thread::is_in_stack(address adr) const { 1061 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 1062 address end = os::current_stack_pointer(); 1063 // Allow non Java threads to call this without stack_base 1064 if (_stack_base == NULL) return true; 1065 if (stack_base() >= adr && adr >= end) return true; 1066 1067 return false; 1068 } 1069 1070 bool Thread::is_in_usable_stack(address adr) const { 1071 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0; 1072 size_t usable_stack_size = _stack_size - stack_guard_size; 1073 1074 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 1075 } 1076 1077 1078 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 1079 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 1080 // used for compilation in the future. If that change is made, the need for these methods 1081 // should be revisited, and they should be removed if possible. 1082 1083 bool Thread::is_lock_owned(address adr) const { 1084 return on_local_stack(adr); 1085 } 1086 1087 bool Thread::set_as_starting_thread() { 1088 assert(_starting_thread == NULL, "already initialized: " 1089 "_starting_thread=" INTPTR_FORMAT, p2i(_starting_thread)); 1090 // NOTE: this must be called inside the main thread. 1091 DEBUG_ONLY(_starting_thread = this;) 1092 return os::create_main_thread((JavaThread*)this); 1093 } 1094 1095 static void initialize_class(Symbol* class_name, TRAPS) { 1096 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 1097 InstanceKlass::cast(klass)->initialize(CHECK); 1098 } 1099 1100 1101 // Creates the initial ThreadGroup 1102 static Handle create_initial_thread_group(TRAPS) { 1103 Handle system_instance = JavaCalls::construct_new_instance( 1104 SystemDictionary::ThreadGroup_klass(), 1105 vmSymbols::void_method_signature(), 1106 CHECK_NH); 1107 Universe::set_system_thread_group(system_instance()); 1108 1109 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 1110 Handle main_instance = JavaCalls::construct_new_instance( 1111 SystemDictionary::ThreadGroup_klass(), 1112 vmSymbols::threadgroup_string_void_signature(), 1113 system_instance, 1114 string, 1115 CHECK_NH); 1116 return main_instance; 1117 } 1118 1119 // Creates the initial Thread 1120 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 1121 TRAPS) { 1122 InstanceKlass* ik = SystemDictionary::Thread_klass(); 1123 assert(ik->is_initialized(), "must be"); 1124 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL); 1125 1126 // Cannot use JavaCalls::construct_new_instance because the java.lang.Thread 1127 // constructor calls Thread.current(), which must be set here for the 1128 // initial thread. 1129 java_lang_Thread::set_thread(thread_oop(), thread); 1130 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1131 thread->set_threadObj(thread_oop()); 1132 1133 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1134 1135 JavaValue result(T_VOID); 1136 JavaCalls::call_special(&result, thread_oop, 1137 ik, 1138 vmSymbols::object_initializer_name(), 1139 vmSymbols::threadgroup_string_void_signature(), 1140 thread_group, 1141 string, 1142 CHECK_NULL); 1143 return thread_oop(); 1144 } 1145 1146 char java_runtime_name[128] = ""; 1147 char java_runtime_version[128] = ""; 1148 1149 // extract the JRE name from java.lang.VersionProps.java_runtime_name 1150 static const char* get_java_runtime_name(TRAPS) { 1151 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1152 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1153 fieldDescriptor fd; 1154 bool found = k != NULL && 1155 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1156 vmSymbols::string_signature(), &fd); 1157 if (found) { 1158 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1159 if (name_oop == NULL) { 1160 return NULL; 1161 } 1162 const char* name = java_lang_String::as_utf8_string(name_oop, 1163 java_runtime_name, 1164 sizeof(java_runtime_name)); 1165 return name; 1166 } else { 1167 return NULL; 1168 } 1169 } 1170 1171 // extract the JRE version from java.lang.VersionProps.java_runtime_version 1172 static const char* get_java_runtime_version(TRAPS) { 1173 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1174 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1175 fieldDescriptor fd; 1176 bool found = k != NULL && 1177 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1178 vmSymbols::string_signature(), &fd); 1179 if (found) { 1180 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1181 if (name_oop == NULL) { 1182 return NULL; 1183 } 1184 const char* name = java_lang_String::as_utf8_string(name_oop, 1185 java_runtime_version, 1186 sizeof(java_runtime_version)); 1187 return name; 1188 } else { 1189 return NULL; 1190 } 1191 } 1192 1193 // General purpose hook into Java code, run once when the VM is initialized. 1194 // The Java library method itself may be changed independently from the VM. 1195 static void call_postVMInitHook(TRAPS) { 1196 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD); 1197 if (klass != NULL) { 1198 JavaValue result(T_VOID); 1199 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1200 vmSymbols::void_method_signature(), 1201 CHECK); 1202 } 1203 } 1204 1205 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 1206 bool daemon, TRAPS) { 1207 assert(thread_group.not_null(), "thread group should be specified"); 1208 assert(threadObj() == NULL, "should only create Java thread object once"); 1209 1210 InstanceKlass* ik = SystemDictionary::Thread_klass(); 1211 assert(ik->is_initialized(), "must be"); 1212 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK); 1213 1214 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon. 1215 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread 1216 // constructor calls Thread.current(), which must be set here. 1217 java_lang_Thread::set_thread(thread_oop(), this); 1218 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1219 set_threadObj(thread_oop()); 1220 1221 JavaValue result(T_VOID); 1222 if (thread_name != NULL) { 1223 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1224 // Thread gets assigned specified name and null target 1225 JavaCalls::call_special(&result, 1226 thread_oop, 1227 ik, 1228 vmSymbols::object_initializer_name(), 1229 vmSymbols::threadgroup_string_void_signature(), 1230 thread_group, 1231 name, 1232 THREAD); 1233 } else { 1234 // Thread gets assigned name "Thread-nnn" and null target 1235 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1236 JavaCalls::call_special(&result, 1237 thread_oop, 1238 ik, 1239 vmSymbols::object_initializer_name(), 1240 vmSymbols::threadgroup_runnable_void_signature(), 1241 thread_group, 1242 Handle(), 1243 THREAD); 1244 } 1245 1246 1247 if (daemon) { 1248 java_lang_Thread::set_daemon(thread_oop()); 1249 } 1250 1251 if (HAS_PENDING_EXCEPTION) { 1252 return; 1253 } 1254 1255 Klass* group = SystemDictionary::ThreadGroup_klass(); 1256 Handle threadObj(THREAD, this->threadObj()); 1257 1258 JavaCalls::call_special(&result, 1259 thread_group, 1260 group, 1261 vmSymbols::add_method_name(), 1262 vmSymbols::thread_void_signature(), 1263 threadObj, // Arg 1 1264 THREAD); 1265 } 1266 1267 // List of all NonJavaThreads and safe iteration over that list. 1268 1269 class NonJavaThread::List { 1270 public: 1271 NonJavaThread* volatile _head; 1272 SingleWriterSynchronizer _protect; 1273 1274 List() : _head(NULL), _protect() {} 1275 }; 1276 1277 NonJavaThread::List NonJavaThread::_the_list; 1278 1279 NonJavaThread::Iterator::Iterator() : 1280 _protect_enter(_the_list._protect.enter()), 1281 _current(OrderAccess::load_acquire(&_the_list._head)) 1282 {} 1283 1284 NonJavaThread::Iterator::~Iterator() { 1285 _the_list._protect.exit(_protect_enter); 1286 } 1287 1288 void NonJavaThread::Iterator::step() { 1289 assert(!end(), "precondition"); 1290 _current = OrderAccess::load_acquire(&_current->_next); 1291 } 1292 1293 NonJavaThread::NonJavaThread() : Thread(), _next(NULL) { 1294 assert(BarrierSet::barrier_set() != NULL, "NonJavaThread created too soon!"); 1295 } 1296 1297 NonJavaThread::~NonJavaThread() { } 1298 1299 void NonJavaThread::add_to_the_list() { 1300 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag); 1301 // Initialize BarrierSet-related data before adding to list. 1302 BarrierSet::barrier_set()->on_thread_attach(this); 1303 OrderAccess::release_store(&_next, _the_list._head); 1304 OrderAccess::release_store(&_the_list._head, this); 1305 } 1306 1307 void NonJavaThread::remove_from_the_list() { 1308 { 1309 MutexLocker ml(NonJavaThreadsList_lock, Mutex::_no_safepoint_check_flag); 1310 // Cleanup BarrierSet-related data before removing from list. 1311 BarrierSet::barrier_set()->on_thread_detach(this); 1312 NonJavaThread* volatile* p = &_the_list._head; 1313 for (NonJavaThread* t = *p; t != NULL; p = &t->_next, t = *p) { 1314 if (t == this) { 1315 *p = _next; 1316 break; 1317 } 1318 } 1319 } 1320 // Wait for any in-progress iterators. Concurrent synchronize is not 1321 // allowed, so do it while holding a dedicated lock. Outside and distinct 1322 // from NJTList_lock in case an iteration attempts to lock it. 1323 MutexLocker ml(NonJavaThreadsListSync_lock, Mutex::_no_safepoint_check_flag); 1324 _the_list._protect.synchronize(); 1325 _next = NULL; // Safe to drop the link now. 1326 } 1327 1328 void NonJavaThread::pre_run() { 1329 add_to_the_list(); 1330 1331 // This is slightly odd in that NamedThread is a subclass, but 1332 // in fact name() is defined in Thread 1333 assert(this->name() != NULL, "thread name was not set before it was started"); 1334 this->set_native_thread_name(this->name()); 1335 } 1336 1337 void NonJavaThread::post_run() { 1338 JFR_ONLY(Jfr::on_thread_exit(this);) 1339 remove_from_the_list(); 1340 // Ensure thread-local-storage is cleared before termination. 1341 Thread::clear_thread_current(); 1342 } 1343 1344 // NamedThread -- non-JavaThread subclasses with multiple 1345 // uniquely named instances should derive from this. 1346 NamedThread::NamedThread() : 1347 NonJavaThread(), 1348 _name(NULL), 1349 _processed_thread(NULL), 1350 _gc_id(GCId::undefined()) 1351 {} 1352 1353 NamedThread::~NamedThread() { 1354 if (_name != NULL) { 1355 FREE_C_HEAP_ARRAY(char, _name); 1356 _name = NULL; 1357 } 1358 } 1359 1360 void NamedThread::set_name(const char* format, ...) { 1361 guarantee(_name == NULL, "Only get to set name once."); 1362 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1363 guarantee(_name != NULL, "alloc failure"); 1364 va_list ap; 1365 va_start(ap, format); 1366 jio_vsnprintf(_name, max_name_len, format, ap); 1367 va_end(ap); 1368 } 1369 1370 void NamedThread::print_on(outputStream* st) const { 1371 st->print("\"%s\" ", name()); 1372 Thread::print_on(st); 1373 st->cr(); 1374 } 1375 1376 1377 // ======= WatcherThread ======== 1378 1379 // The watcher thread exists to simulate timer interrupts. It should 1380 // be replaced by an abstraction over whatever native support for 1381 // timer interrupts exists on the platform. 1382 1383 WatcherThread* WatcherThread::_watcher_thread = NULL; 1384 bool WatcherThread::_startable = false; 1385 volatile bool WatcherThread::_should_terminate = false; 1386 1387 WatcherThread::WatcherThread() : NonJavaThread() { 1388 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1389 if (os::create_thread(this, os::watcher_thread)) { 1390 _watcher_thread = this; 1391 1392 // Set the watcher thread to the highest OS priority which should not be 1393 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1394 // is created. The only normal thread using this priority is the reference 1395 // handler thread, which runs for very short intervals only. 1396 // If the VMThread's priority is not lower than the WatcherThread profiling 1397 // will be inaccurate. 1398 os::set_priority(this, MaxPriority); 1399 if (!DisableStartThread) { 1400 os::start_thread(this); 1401 } 1402 } 1403 } 1404 1405 int WatcherThread::sleep() const { 1406 // The WatcherThread does not participate in the safepoint protocol 1407 // for the PeriodicTask_lock because it is not a JavaThread. 1408 MonitorLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1409 1410 if (_should_terminate) { 1411 // check for termination before we do any housekeeping or wait 1412 return 0; // we did not sleep. 1413 } 1414 1415 // remaining will be zero if there are no tasks, 1416 // causing the WatcherThread to sleep until a task is 1417 // enrolled 1418 int remaining = PeriodicTask::time_to_wait(); 1419 int time_slept = 0; 1420 1421 // we expect this to timeout - we only ever get unparked when 1422 // we should terminate or when a new task has been enrolled 1423 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1424 1425 jlong time_before_loop = os::javaTimeNanos(); 1426 1427 while (true) { 1428 bool timedout = ml.wait(remaining); 1429 jlong now = os::javaTimeNanos(); 1430 1431 if (remaining == 0) { 1432 // if we didn't have any tasks we could have waited for a long time 1433 // consider the time_slept zero and reset time_before_loop 1434 time_slept = 0; 1435 time_before_loop = now; 1436 } else { 1437 // need to recalculate since we might have new tasks in _tasks 1438 time_slept = (int) ((now - time_before_loop) / 1000000); 1439 } 1440 1441 // Change to task list or spurious wakeup of some kind 1442 if (timedout || _should_terminate) { 1443 break; 1444 } 1445 1446 remaining = PeriodicTask::time_to_wait(); 1447 if (remaining == 0) { 1448 // Last task was just disenrolled so loop around and wait until 1449 // another task gets enrolled 1450 continue; 1451 } 1452 1453 remaining -= time_slept; 1454 if (remaining <= 0) { 1455 break; 1456 } 1457 } 1458 1459 return time_slept; 1460 } 1461 1462 void WatcherThread::run() { 1463 assert(this == watcher_thread(), "just checking"); 1464 1465 this->set_active_handles(JNIHandleBlock::allocate_block()); 1466 while (true) { 1467 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1468 assert(watcher_thread() == this, "thread consistency check"); 1469 1470 // Calculate how long it'll be until the next PeriodicTask work 1471 // should be done, and sleep that amount of time. 1472 int time_waited = sleep(); 1473 1474 if (VMError::is_error_reported()) { 1475 // A fatal error has happened, the error handler(VMError::report_and_die) 1476 // should abort JVM after creating an error log file. However in some 1477 // rare cases, the error handler itself might deadlock. Here periodically 1478 // check for error reporting timeouts, and if it happens, just proceed to 1479 // abort the VM. 1480 1481 // This code is in WatcherThread because WatcherThread wakes up 1482 // periodically so the fatal error handler doesn't need to do anything; 1483 // also because the WatcherThread is less likely to crash than other 1484 // threads. 1485 1486 for (;;) { 1487 // Note: we use naked sleep in this loop because we want to avoid using 1488 // any kind of VM infrastructure which may be broken at this point. 1489 if (VMError::check_timeout()) { 1490 // We hit error reporting timeout. Error reporting was interrupted and 1491 // will be wrapping things up now (closing files etc). Give it some more 1492 // time, then quit the VM. 1493 os::naked_short_sleep(200); 1494 // Print a message to stderr. 1495 fdStream err(defaultStream::output_fd()); 1496 err.print_raw_cr("# [ timer expired, abort... ]"); 1497 // skip atexit/vm_exit/vm_abort hooks 1498 os::die(); 1499 } 1500 1501 // Wait a second, then recheck for timeout. 1502 os::naked_short_sleep(999); 1503 } 1504 } 1505 1506 if (_should_terminate) { 1507 // check for termination before posting the next tick 1508 break; 1509 } 1510 1511 PeriodicTask::real_time_tick(time_waited); 1512 } 1513 1514 // Signal that it is terminated 1515 { 1516 MutexLocker mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1517 _watcher_thread = NULL; 1518 Terminator_lock->notify_all(); 1519 } 1520 } 1521 1522 void WatcherThread::start() { 1523 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1524 1525 if (watcher_thread() == NULL && _startable) { 1526 _should_terminate = false; 1527 // Create the single instance of WatcherThread 1528 new WatcherThread(); 1529 } 1530 } 1531 1532 void WatcherThread::make_startable() { 1533 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1534 _startable = true; 1535 } 1536 1537 void WatcherThread::stop() { 1538 { 1539 // Follow normal safepoint aware lock enter protocol since the 1540 // WatcherThread is stopped by another JavaThread. 1541 MutexLocker ml(PeriodicTask_lock); 1542 _should_terminate = true; 1543 1544 WatcherThread* watcher = watcher_thread(); 1545 if (watcher != NULL) { 1546 // unpark the WatcherThread so it can see that it should terminate 1547 watcher->unpark(); 1548 } 1549 } 1550 1551 MonitorLocker mu(Terminator_lock); 1552 1553 while (watcher_thread() != NULL) { 1554 // This wait should make safepoint checks, wait without a timeout, 1555 // and wait as a suspend-equivalent condition. 1556 mu.wait(0, Mutex::_as_suspend_equivalent_flag); 1557 } 1558 } 1559 1560 void WatcherThread::unpark() { 1561 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1562 PeriodicTask_lock->notify(); 1563 } 1564 1565 void WatcherThread::print_on(outputStream* st) const { 1566 st->print("\"%s\" ", name()); 1567 Thread::print_on(st); 1568 st->cr(); 1569 } 1570 1571 // ======= JavaThread ======== 1572 1573 #if INCLUDE_JVMCI 1574 1575 jlong* JavaThread::_jvmci_old_thread_counters; 1576 1577 bool jvmci_counters_include(JavaThread* thread) { 1578 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); 1579 } 1580 1581 void JavaThread::collect_counters(jlong* array, int length) { 1582 assert(length == JVMCICounterSize, "wrong value"); 1583 for (int i = 0; i < length; i++) { 1584 array[i] = _jvmci_old_thread_counters[i]; 1585 } 1586 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) { 1587 if (jvmci_counters_include(tp)) { 1588 for (int i = 0; i < length; i++) { 1589 array[i] += tp->_jvmci_counters[i]; 1590 } 1591 } 1592 } 1593 } 1594 1595 // Attempt to enlarge the array for per thread counters. 1596 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) { 1597 jlong* new_counters = NEW_C_HEAP_ARRAY(jlong, new_size, mtJVMCI); 1598 if (new_counters == NULL) { 1599 return NULL; 1600 } 1601 if (old_counters == NULL) { 1602 old_counters = new_counters; 1603 memset(old_counters, 0, sizeof(jlong) * new_size); 1604 } else { 1605 for (int i = 0; i < MIN2((int) current_size, new_size); i++) { 1606 new_counters[i] = old_counters[i]; 1607 } 1608 if (new_size > current_size) { 1609 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size)); 1610 } 1611 FREE_C_HEAP_ARRAY(jlong, old_counters); 1612 } 1613 return new_counters; 1614 } 1615 1616 // Attempt to enlarge the array for per thread counters. 1617 bool JavaThread::resize_counters(int current_size, int new_size) { 1618 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size); 1619 if (new_counters == NULL) { 1620 return false; 1621 } else { 1622 _jvmci_counters = new_counters; 1623 return true; 1624 } 1625 } 1626 1627 class VM_JVMCIResizeCounters : public VM_Operation { 1628 private: 1629 int _new_size; 1630 bool _failed; 1631 1632 public: 1633 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { } 1634 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; } 1635 bool allow_nested_vm_operations() const { return true; } 1636 void doit() { 1637 // Resize the old thread counters array 1638 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size); 1639 if (new_counters == NULL) { 1640 _failed = true; 1641 return; 1642 } else { 1643 JavaThread::_jvmci_old_thread_counters = new_counters; 1644 } 1645 1646 // Now resize each threads array 1647 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *tp = jtiwh.next(); ) { 1648 if (!tp->resize_counters(JVMCICounterSize, _new_size)) { 1649 _failed = true; 1650 break; 1651 } 1652 } 1653 if (!_failed) { 1654 JVMCICounterSize = _new_size; 1655 } 1656 } 1657 1658 bool failed() { return _failed; } 1659 }; 1660 1661 bool JavaThread::resize_all_jvmci_counters(int new_size) { 1662 VM_JVMCIResizeCounters op(new_size); 1663 VMThread::execute(&op); 1664 return !op.failed(); 1665 } 1666 1667 #endif // INCLUDE_JVMCI 1668 1669 // A JavaThread is a normal Java thread 1670 1671 void JavaThread::initialize() { 1672 // Initialize fields 1673 1674 set_saved_exception_pc(NULL); 1675 set_threadObj(NULL); 1676 _anchor.clear(); 1677 set_entry_point(NULL); 1678 set_jni_functions(jni_functions()); 1679 set_callee_target(NULL); 1680 set_vm_result(NULL); 1681 set_vm_result_2(NULL); 1682 set_vframe_array_head(NULL); 1683 set_vframe_array_last(NULL); 1684 set_deferred_locals(NULL); 1685 set_deopt_mark(NULL); 1686 set_deopt_compiled_method(NULL); 1687 clear_must_deopt_id(); 1688 set_monitor_chunks(NULL); 1689 _on_thread_list = false; 1690 set_thread_state(_thread_new); 1691 _terminated = _not_terminated; 1692 _array_for_gc = NULL; 1693 _suspend_equivalent = false; 1694 _in_deopt_handler = 0; 1695 _doing_unsafe_access = false; 1696 _stack_guard_state = stack_guard_unused; 1697 #if INCLUDE_JVMCI 1698 _pending_monitorenter = false; 1699 _pending_deoptimization = -1; 1700 _pending_failed_speculation = 0; 1701 _pending_transfer_to_interpreter = false; 1702 _in_retryable_allocation = false; 1703 _jvmci._alternate_call_target = NULL; 1704 assert(_jvmci._implicit_exception_pc == NULL, "must be"); 1705 _jvmci_counters = NULL; 1706 if (JVMCICounterSize > 0) { 1707 resize_counters(0, (int) JVMCICounterSize); 1708 } 1709 #endif // INCLUDE_JVMCI 1710 _reserved_stack_activation = NULL; // stack base not known yet 1711 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1712 _exception_pc = 0; 1713 _exception_handler_pc = 0; 1714 _is_method_handle_return = 0; 1715 _jvmti_thread_state= NULL; 1716 _should_post_on_exceptions_flag = JNI_FALSE; 1717 _interp_only_mode = 0; 1718 _special_runtime_exit_condition = _no_async_condition; 1719 _pending_async_exception = NULL; 1720 _thread_stat = NULL; 1721 _thread_stat = new ThreadStatistics(); 1722 _blocked_on_compilation = false; 1723 _jni_active_critical = 0; 1724 _pending_jni_exception_check_fn = NULL; 1725 _do_not_unlock_if_synchronized = false; 1726 _cached_monitor_info = NULL; 1727 _parker = Parker::Allocate(this); 1728 1729 #ifndef PRODUCT 1730 _jmp_ring_index = 0; 1731 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1732 record_jump(NULL, NULL, NULL, 0); 1733 } 1734 #endif // PRODUCT 1735 1736 // Setup safepoint state info for this thread 1737 ThreadSafepointState::create(this); 1738 1739 debug_only(_java_call_counter = 0); 1740 1741 // JVMTI PopFrame support 1742 _popframe_condition = popframe_inactive; 1743 _popframe_preserved_args = NULL; 1744 _popframe_preserved_args_size = 0; 1745 _frames_to_pop_failed_realloc = 0; 1746 1747 if (SafepointMechanism::uses_thread_local_poll()) { 1748 SafepointMechanism::initialize_header(this); 1749 } 1750 1751 _class_to_be_initialized = NULL; 1752 1753 pd_initialize(); 1754 } 1755 1756 JavaThread::JavaThread(bool is_attaching_via_jni) : 1757 Thread() { 1758 initialize(); 1759 if (is_attaching_via_jni) { 1760 _jni_attach_state = _attaching_via_jni; 1761 } else { 1762 _jni_attach_state = _not_attaching_via_jni; 1763 } 1764 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1765 } 1766 1767 bool JavaThread::reguard_stack(address cur_sp) { 1768 if (_stack_guard_state != stack_guard_yellow_reserved_disabled 1769 && _stack_guard_state != stack_guard_reserved_disabled) { 1770 return true; // Stack already guarded or guard pages not needed. 1771 } 1772 1773 if (register_stack_overflow()) { 1774 // For those architectures which have separate register and 1775 // memory stacks, we must check the register stack to see if 1776 // it has overflowed. 1777 return false; 1778 } 1779 1780 // Java code never executes within the yellow zone: the latter is only 1781 // there to provoke an exception during stack banging. If java code 1782 // is executing there, either StackShadowPages should be larger, or 1783 // some exception code in c1, c2 or the interpreter isn't unwinding 1784 // when it should. 1785 guarantee(cur_sp > stack_reserved_zone_base(), 1786 "not enough space to reguard - increase StackShadowPages"); 1787 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) { 1788 enable_stack_yellow_reserved_zone(); 1789 if (reserved_stack_activation() != stack_base()) { 1790 set_reserved_stack_activation(stack_base()); 1791 } 1792 } else if (_stack_guard_state == stack_guard_reserved_disabled) { 1793 set_reserved_stack_activation(stack_base()); 1794 enable_stack_reserved_zone(); 1795 } 1796 return true; 1797 } 1798 1799 bool JavaThread::reguard_stack(void) { 1800 return reguard_stack(os::current_stack_pointer()); 1801 } 1802 1803 1804 void JavaThread::block_if_vm_exited() { 1805 if (_terminated == _vm_exited) { 1806 // _vm_exited is set at safepoint, and Threads_lock is never released 1807 // we will block here forever 1808 Threads_lock->lock_without_safepoint_check(); 1809 ShouldNotReachHere(); 1810 } 1811 } 1812 1813 1814 // Remove this ifdef when C1 is ported to the compiler interface. 1815 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1816 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1817 1818 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1819 Thread() { 1820 initialize(); 1821 _jni_attach_state = _not_attaching_via_jni; 1822 set_entry_point(entry_point); 1823 // Create the native thread itself. 1824 // %note runtime_23 1825 os::ThreadType thr_type = os::java_thread; 1826 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1827 os::java_thread; 1828 os::create_thread(this, thr_type, stack_sz); 1829 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1830 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1831 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1832 // the exception consists of creating the exception object & initializing it, initialization 1833 // will leave the VM via a JavaCall and then all locks must be unlocked). 1834 // 1835 // The thread is still suspended when we reach here. Thread must be explicit started 1836 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1837 // by calling Threads:add. The reason why this is not done here, is because the thread 1838 // object must be fully initialized (take a look at JVM_Start) 1839 } 1840 1841 JavaThread::~JavaThread() { 1842 1843 // JSR166 -- return the parker to the free list 1844 Parker::Release(_parker); 1845 _parker = NULL; 1846 1847 // Free any remaining previous UnrollBlock 1848 vframeArray* old_array = vframe_array_last(); 1849 1850 if (old_array != NULL) { 1851 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1852 old_array->set_unroll_block(NULL); 1853 delete old_info; 1854 delete old_array; 1855 } 1856 1857 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1858 if (deferred != NULL) { 1859 // This can only happen if thread is destroyed before deoptimization occurs. 1860 assert(deferred->length() != 0, "empty array!"); 1861 do { 1862 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1863 deferred->remove_at(0); 1864 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1865 delete dlv; 1866 } while (deferred->length() != 0); 1867 delete deferred; 1868 } 1869 1870 // All Java related clean up happens in exit 1871 ThreadSafepointState::destroy(this); 1872 if (_thread_stat != NULL) delete _thread_stat; 1873 1874 #if INCLUDE_JVMCI 1875 if (JVMCICounterSize > 0) { 1876 if (jvmci_counters_include(this)) { 1877 for (int i = 0; i < JVMCICounterSize; i++) { 1878 _jvmci_old_thread_counters[i] += _jvmci_counters[i]; 1879 } 1880 } 1881 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); 1882 } 1883 #endif // INCLUDE_JVMCI 1884 } 1885 1886 1887 // First JavaThread specific code executed by a new Java thread. 1888 void JavaThread::pre_run() { 1889 // empty - see comments in run() 1890 } 1891 1892 // The main routine called by a new Java thread. This isn't overridden 1893 // by subclasses, instead different subclasses define a different "entry_point" 1894 // which defines the actual logic for that kind of thread. 1895 void JavaThread::run() { 1896 // initialize thread-local alloc buffer related fields 1897 this->initialize_tlab(); 1898 1899 // Used to test validity of stack trace backs. 1900 // This can't be moved into pre_run() else we invalidate 1901 // the requirement that thread_main_inner is lower on 1902 // the stack. Consequently all the initialization logic 1903 // stays here in run() rather than pre_run(). 1904 this->record_base_of_stack_pointer(); 1905 1906 this->create_stack_guard_pages(); 1907 1908 this->cache_global_variables(); 1909 1910 // Thread is now sufficiently initialized to be handled by the safepoint code as being 1911 // in the VM. Change thread state from _thread_new to _thread_in_vm 1912 ThreadStateTransition::transition(this, _thread_new, _thread_in_vm); 1913 // Before a thread is on the threads list it is always safe, so after leaving the 1914 // _thread_new we should emit a instruction barrier. The distance to modified code 1915 // from here is probably far enough, but this is consistent and safe. 1916 OrderAccess::cross_modify_fence(); 1917 1918 assert(JavaThread::current() == this, "sanity check"); 1919 assert(!Thread::current()->owns_locks(), "sanity check"); 1920 1921 DTRACE_THREAD_PROBE(start, this); 1922 1923 // This operation might block. We call that after all safepoint checks for a new thread has 1924 // been completed. 1925 this->set_active_handles(JNIHandleBlock::allocate_block()); 1926 1927 if (JvmtiExport::should_post_thread_life()) { 1928 JvmtiExport::post_thread_start(this); 1929 1930 } 1931 1932 // We call another function to do the rest so we are sure that the stack addresses used 1933 // from there will be lower than the stack base just computed. 1934 thread_main_inner(); 1935 } 1936 1937 void JavaThread::thread_main_inner() { 1938 assert(JavaThread::current() == this, "sanity check"); 1939 assert(this->threadObj() != NULL, "just checking"); 1940 1941 // Execute thread entry point unless this thread has a pending exception 1942 // or has been stopped before starting. 1943 // Note: Due to JVM_StopThread we can have pending exceptions already! 1944 if (!this->has_pending_exception() && 1945 !java_lang_Thread::is_stillborn(this->threadObj())) { 1946 { 1947 ResourceMark rm(this); 1948 this->set_native_thread_name(this->get_thread_name()); 1949 } 1950 HandleMark hm(this); 1951 this->entry_point()(this, this); 1952 } 1953 1954 DTRACE_THREAD_PROBE(stop, this); 1955 1956 // Cleanup is handled in post_run() 1957 } 1958 1959 // Shared teardown for all JavaThreads 1960 void JavaThread::post_run() { 1961 this->exit(false); 1962 // Defer deletion to here to ensure 'this' is still referenceable in call_run 1963 // for any shared tear-down. 1964 this->smr_delete(); 1965 } 1966 1967 static void ensure_join(JavaThread* thread) { 1968 // We do not need to grab the Threads_lock, since we are operating on ourself. 1969 Handle threadObj(thread, thread->threadObj()); 1970 assert(threadObj.not_null(), "java thread object must exist"); 1971 ObjectLocker lock(threadObj, thread); 1972 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1973 thread->clear_pending_exception(); 1974 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1975 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1976 // Clear the native thread instance - this makes isAlive return false and allows the join() 1977 // to complete once we've done the notify_all below 1978 java_lang_Thread::set_thread(threadObj(), NULL); 1979 lock.notify_all(thread); 1980 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1981 thread->clear_pending_exception(); 1982 } 1983 1984 static bool is_daemon(oop threadObj) { 1985 return (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)); 1986 } 1987 1988 // For any new cleanup additions, please check to see if they need to be applied to 1989 // cleanup_failed_attach_current_thread as well. 1990 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1991 assert(this == JavaThread::current(), "thread consistency check"); 1992 1993 elapsedTimer _timer_exit_phase1; 1994 elapsedTimer _timer_exit_phase2; 1995 elapsedTimer _timer_exit_phase3; 1996 elapsedTimer _timer_exit_phase4; 1997 1998 if (log_is_enabled(Debug, os, thread, timer)) { 1999 _timer_exit_phase1.start(); 2000 } 2001 2002 HandleMark hm(this); 2003 Handle uncaught_exception(this, this->pending_exception()); 2004 this->clear_pending_exception(); 2005 Handle threadObj(this, this->threadObj()); 2006 assert(threadObj.not_null(), "Java thread object should be created"); 2007 2008 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 2009 { 2010 EXCEPTION_MARK; 2011 2012 CLEAR_PENDING_EXCEPTION; 2013 } 2014 if (!destroy_vm) { 2015 if (uncaught_exception.not_null()) { 2016 EXCEPTION_MARK; 2017 // Call method Thread.dispatchUncaughtException(). 2018 Klass* thread_klass = SystemDictionary::Thread_klass(); 2019 JavaValue result(T_VOID); 2020 JavaCalls::call_virtual(&result, 2021 threadObj, thread_klass, 2022 vmSymbols::dispatchUncaughtException_name(), 2023 vmSymbols::throwable_void_signature(), 2024 uncaught_exception, 2025 THREAD); 2026 if (HAS_PENDING_EXCEPTION) { 2027 ResourceMark rm(this); 2028 jio_fprintf(defaultStream::error_stream(), 2029 "\nException: %s thrown from the UncaughtExceptionHandler" 2030 " in thread \"%s\"\n", 2031 pending_exception()->klass()->external_name(), 2032 get_thread_name()); 2033 CLEAR_PENDING_EXCEPTION; 2034 } 2035 } 2036 JFR_ONLY(Jfr::on_java_thread_dismantle(this);) 2037 2038 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 2039 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 2040 // is deprecated anyhow. 2041 if (!is_Compiler_thread()) { 2042 int count = 3; 2043 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 2044 EXCEPTION_MARK; 2045 JavaValue result(T_VOID); 2046 Klass* thread_klass = SystemDictionary::Thread_klass(); 2047 JavaCalls::call_virtual(&result, 2048 threadObj, thread_klass, 2049 vmSymbols::exit_method_name(), 2050 vmSymbols::void_method_signature(), 2051 THREAD); 2052 CLEAR_PENDING_EXCEPTION; 2053 } 2054 } 2055 // notify JVMTI 2056 if (JvmtiExport::should_post_thread_life()) { 2057 JvmtiExport::post_thread_end(this); 2058 } 2059 2060 // We have notified the agents that we are exiting, before we go on, 2061 // we must check for a pending external suspend request and honor it 2062 // in order to not surprise the thread that made the suspend request. 2063 while (true) { 2064 { 2065 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2066 if (!is_external_suspend()) { 2067 set_terminated(_thread_exiting); 2068 ThreadService::current_thread_exiting(this, is_daemon(threadObj())); 2069 break; 2070 } 2071 // Implied else: 2072 // Things get a little tricky here. We have a pending external 2073 // suspend request, but we are holding the SR_lock so we 2074 // can't just self-suspend. So we temporarily drop the lock 2075 // and then self-suspend. 2076 } 2077 2078 ThreadBlockInVM tbivm(this); 2079 java_suspend_self(); 2080 2081 // We're done with this suspend request, but we have to loop around 2082 // and check again. Eventually we will get SR_lock without a pending 2083 // external suspend request and will be able to mark ourselves as 2084 // exiting. 2085 } 2086 // no more external suspends are allowed at this point 2087 } else { 2088 assert(!is_terminated() && !is_exiting(), "must not be exiting"); 2089 // before_exit() has already posted JVMTI THREAD_END events 2090 } 2091 2092 if (log_is_enabled(Debug, os, thread, timer)) { 2093 _timer_exit_phase1.stop(); 2094 _timer_exit_phase2.start(); 2095 } 2096 2097 // Capture daemon status before the thread is marked as terminated. 2098 bool daemon = is_daemon(threadObj()); 2099 2100 // Notify waiters on thread object. This has to be done after exit() is called 2101 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 2102 // group should have the destroyed bit set before waiters are notified). 2103 ensure_join(this); 2104 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 2105 2106 if (log_is_enabled(Debug, os, thread, timer)) { 2107 _timer_exit_phase2.stop(); 2108 _timer_exit_phase3.start(); 2109 } 2110 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 2111 // held by this thread must be released. The spec does not distinguish 2112 // between JNI-acquired and regular Java monitors. We can only see 2113 // regular Java monitors here if monitor enter-exit matching is broken. 2114 // 2115 // ensure_join() ignores IllegalThreadStateExceptions, and so does 2116 // ObjectSynchronizer::release_monitors_owned_by_thread(). 2117 if (exit_type == jni_detach) { 2118 // Sanity check even though JNI DetachCurrentThread() would have 2119 // returned JNI_ERR if there was a Java frame. JavaThread exit 2120 // should be done executing Java code by the time we get here. 2121 assert(!this->has_last_Java_frame(), 2122 "should not have a Java frame when detaching or exiting"); 2123 ObjectSynchronizer::release_monitors_owned_by_thread(this); 2124 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 2125 } 2126 2127 // These things needs to be done while we are still a Java Thread. Make sure that thread 2128 // is in a consistent state, in case GC happens 2129 JFR_ONLY(Jfr::on_thread_exit(this);) 2130 2131 if (active_handles() != NULL) { 2132 JNIHandleBlock* block = active_handles(); 2133 set_active_handles(NULL); 2134 JNIHandleBlock::release_block(block); 2135 } 2136 2137 if (free_handle_block() != NULL) { 2138 JNIHandleBlock* block = free_handle_block(); 2139 set_free_handle_block(NULL); 2140 JNIHandleBlock::release_block(block); 2141 } 2142 2143 // These have to be removed while this is still a valid thread. 2144 remove_stack_guard_pages(); 2145 2146 if (UseTLAB) { 2147 tlab().retire(); 2148 } 2149 2150 if (JvmtiEnv::environments_might_exist()) { 2151 JvmtiExport::cleanup_thread(this); 2152 } 2153 2154 // We must flush any deferred card marks and other various GC barrier 2155 // related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer) 2156 // before removing a thread from the list of active threads. 2157 BarrierSet::barrier_set()->on_thread_detach(this); 2158 2159 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").", 2160 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", 2161 os::current_thread_id()); 2162 2163 if (log_is_enabled(Debug, os, thread, timer)) { 2164 _timer_exit_phase3.stop(); 2165 _timer_exit_phase4.start(); 2166 } 2167 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 2168 Threads::remove(this, daemon); 2169 2170 if (log_is_enabled(Debug, os, thread, timer)) { 2171 _timer_exit_phase4.stop(); 2172 ResourceMark rm(this); 2173 log_debug(os, thread, timer)("name='%s'" 2174 ", exit-phase1=" JLONG_FORMAT 2175 ", exit-phase2=" JLONG_FORMAT 2176 ", exit-phase3=" JLONG_FORMAT 2177 ", exit-phase4=" JLONG_FORMAT, 2178 get_thread_name(), 2179 _timer_exit_phase1.milliseconds(), 2180 _timer_exit_phase2.milliseconds(), 2181 _timer_exit_phase3.milliseconds(), 2182 _timer_exit_phase4.milliseconds()); 2183 } 2184 } 2185 2186 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) { 2187 if (active_handles() != NULL) { 2188 JNIHandleBlock* block = active_handles(); 2189 set_active_handles(NULL); 2190 JNIHandleBlock::release_block(block); 2191 } 2192 2193 if (free_handle_block() != NULL) { 2194 JNIHandleBlock* block = free_handle_block(); 2195 set_free_handle_block(NULL); 2196 JNIHandleBlock::release_block(block); 2197 } 2198 2199 // These have to be removed while this is still a valid thread. 2200 remove_stack_guard_pages(); 2201 2202 if (UseTLAB) { 2203 tlab().retire(); 2204 } 2205 2206 BarrierSet::barrier_set()->on_thread_detach(this); 2207 2208 Threads::remove(this, is_daemon); 2209 this->smr_delete(); 2210 } 2211 2212 JavaThread* JavaThread::active() { 2213 Thread* thread = Thread::current(); 2214 if (thread->is_Java_thread()) { 2215 return (JavaThread*) thread; 2216 } else { 2217 assert(thread->is_VM_thread(), "this must be a vm thread"); 2218 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2219 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2220 assert(ret->is_Java_thread(), "must be a Java thread"); 2221 return ret; 2222 } 2223 } 2224 2225 bool JavaThread::is_lock_owned(address adr) const { 2226 if (Thread::is_lock_owned(adr)) return true; 2227 2228 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2229 if (chunk->contains(adr)) return true; 2230 } 2231 2232 return false; 2233 } 2234 2235 2236 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2237 chunk->set_next(monitor_chunks()); 2238 set_monitor_chunks(chunk); 2239 } 2240 2241 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2242 guarantee(monitor_chunks() != NULL, "must be non empty"); 2243 if (monitor_chunks() == chunk) { 2244 set_monitor_chunks(chunk->next()); 2245 } else { 2246 MonitorChunk* prev = monitor_chunks(); 2247 while (prev->next() != chunk) prev = prev->next(); 2248 prev->set_next(chunk->next()); 2249 } 2250 } 2251 2252 // JVM support. 2253 2254 // Note: this function shouldn't block if it's called in 2255 // _thread_in_native_trans state (such as from 2256 // check_special_condition_for_native_trans()). 2257 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2258 2259 if (has_last_Java_frame() && has_async_condition()) { 2260 // If we are at a polling page safepoint (not a poll return) 2261 // then we must defer async exception because live registers 2262 // will be clobbered by the exception path. Poll return is 2263 // ok because the call we a returning from already collides 2264 // with exception handling registers and so there is no issue. 2265 // (The exception handling path kills call result registers but 2266 // this is ok since the exception kills the result anyway). 2267 2268 if (is_at_poll_safepoint()) { 2269 // if the code we are returning to has deoptimized we must defer 2270 // the exception otherwise live registers get clobbered on the 2271 // exception path before deoptimization is able to retrieve them. 2272 // 2273 RegisterMap map(this, false); 2274 frame caller_fr = last_frame().sender(&map); 2275 assert(caller_fr.is_compiled_frame(), "what?"); 2276 if (caller_fr.is_deoptimized_frame()) { 2277 log_info(exceptions)("deferred async exception at compiled safepoint"); 2278 return; 2279 } 2280 } 2281 } 2282 2283 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2284 if (condition == _no_async_condition) { 2285 // Conditions have changed since has_special_runtime_exit_condition() 2286 // was called: 2287 // - if we were here only because of an external suspend request, 2288 // then that was taken care of above (or cancelled) so we are done 2289 // - if we were here because of another async request, then it has 2290 // been cleared between the has_special_runtime_exit_condition() 2291 // and now so again we are done 2292 return; 2293 } 2294 2295 // Check for pending async. exception 2296 if (_pending_async_exception != NULL) { 2297 // Only overwrite an already pending exception, if it is not a threadDeath. 2298 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2299 2300 // We cannot call Exceptions::_throw(...) here because we cannot block 2301 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2302 2303 LogTarget(Info, exceptions) lt; 2304 if (lt.is_enabled()) { 2305 ResourceMark rm; 2306 LogStream ls(lt); 2307 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); 2308 if (has_last_Java_frame()) { 2309 frame f = last_frame(); 2310 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); 2311 } 2312 ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name()); 2313 } 2314 _pending_async_exception = NULL; 2315 clear_has_async_exception(); 2316 } 2317 } 2318 2319 if (check_unsafe_error && 2320 condition == _async_unsafe_access_error && !has_pending_exception()) { 2321 condition = _no_async_condition; // done 2322 switch (thread_state()) { 2323 case _thread_in_vm: { 2324 JavaThread* THREAD = this; 2325 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2326 } 2327 case _thread_in_native: { 2328 ThreadInVMfromNative tiv(this); 2329 JavaThread* THREAD = this; 2330 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2331 } 2332 case _thread_in_Java: { 2333 ThreadInVMfromJava tiv(this); 2334 JavaThread* THREAD = this; 2335 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2336 } 2337 default: 2338 ShouldNotReachHere(); 2339 } 2340 } 2341 2342 assert(condition == _no_async_condition || has_pending_exception() || 2343 (!check_unsafe_error && condition == _async_unsafe_access_error), 2344 "must have handled the async condition, if no exception"); 2345 } 2346 2347 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2348 // 2349 // Check for pending external suspend. 2350 // If JNIEnv proxies are allowed, don't self-suspend if the target 2351 // thread is not the current thread. In older versions of jdbx, jdbx 2352 // threads could call into the VM with another thread's JNIEnv so we 2353 // can be here operating on behalf of a suspended thread (4432884). 2354 bool do_self_suspend = is_external_suspend_with_lock(); 2355 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2356 frame_anchor()->make_walkable(this); 2357 java_suspend_self_with_safepoint_check(); 2358 } 2359 2360 // We might be here for reasons in addition to the self-suspend request 2361 // so check for other async requests. 2362 if (check_asyncs) { 2363 check_and_handle_async_exceptions(); 2364 } 2365 2366 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);) 2367 } 2368 2369 void JavaThread::send_thread_stop(oop java_throwable) { 2370 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2371 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2372 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2373 2374 // Do not throw asynchronous exceptions against the compiler thread 2375 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2376 if (!can_call_java()) return; 2377 2378 { 2379 // Actually throw the Throwable against the target Thread - however 2380 // only if there is no thread death exception installed already. 2381 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2382 // If the topmost frame is a runtime stub, then we are calling into 2383 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2384 // must deoptimize the caller before continuing, as the compiled exception handler table 2385 // may not be valid 2386 if (has_last_Java_frame()) { 2387 frame f = last_frame(); 2388 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2389 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2390 RegisterMap reg_map(this, UseBiasedLocking); 2391 frame compiled_frame = f.sender(®_map); 2392 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2393 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2394 } 2395 } 2396 } 2397 2398 // Set async. pending exception in thread. 2399 set_pending_async_exception(java_throwable); 2400 2401 if (log_is_enabled(Info, exceptions)) { 2402 ResourceMark rm; 2403 log_info(exceptions)("Pending Async. exception installed of type: %s", 2404 InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2405 } 2406 // for AbortVMOnException flag 2407 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name()); 2408 } 2409 } 2410 2411 2412 // Interrupt thread so it will wake up from a potential wait() 2413 Thread::interrupt(this); 2414 } 2415 2416 // External suspension mechanism. 2417 // 2418 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2419 // to any VM_locks and it is at a transition 2420 // Self-suspension will happen on the transition out of the vm. 2421 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2422 // 2423 // Guarantees on return: 2424 // + Target thread will not execute any new bytecode (that's why we need to 2425 // force a safepoint) 2426 // + Target thread will not enter any new monitors 2427 // 2428 void JavaThread::java_suspend() { 2429 ThreadsListHandle tlh; 2430 if (!tlh.includes(this) || threadObj() == NULL || is_exiting()) { 2431 return; 2432 } 2433 2434 { MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2435 if (!is_external_suspend()) { 2436 // a racing resume has cancelled us; bail out now 2437 return; 2438 } 2439 2440 // suspend is done 2441 uint32_t debug_bits = 0; 2442 // Warning: is_ext_suspend_completed() may temporarily drop the 2443 // SR_lock to allow the thread to reach a stable thread state if 2444 // it is currently in a transient thread state. 2445 if (is_ext_suspend_completed(false /* !called_by_wait */, 2446 SuspendRetryDelay, &debug_bits)) { 2447 return; 2448 } 2449 } 2450 2451 if (Thread::current() == this) { 2452 // Safely self-suspend. 2453 // If we don't do this explicitly it will implicitly happen 2454 // before we transition back to Java, and on some other thread-state 2455 // transition paths, but not as we exit a JVM TI SuspendThread call. 2456 // As SuspendThread(current) must not return (until resumed) we must 2457 // self-suspend here. 2458 ThreadBlockInVM tbivm(this); 2459 java_suspend_self(); 2460 } else { 2461 VM_ThreadSuspend vm_suspend; 2462 VMThread::execute(&vm_suspend); 2463 } 2464 } 2465 2466 // Part II of external suspension. 2467 // A JavaThread self suspends when it detects a pending external suspend 2468 // request. This is usually on transitions. It is also done in places 2469 // where continuing to the next transition would surprise the caller, 2470 // e.g., monitor entry. 2471 // 2472 // Returns the number of times that the thread self-suspended. 2473 // 2474 // Note: DO NOT call java_suspend_self() when you just want to block current 2475 // thread. java_suspend_self() is the second stage of cooperative 2476 // suspension for external suspend requests and should only be used 2477 // to complete an external suspend request. 2478 // 2479 int JavaThread::java_suspend_self() { 2480 assert(thread_state() == _thread_blocked, "wrong state for java_suspend_self()"); 2481 int ret = 0; 2482 2483 // we are in the process of exiting so don't suspend 2484 if (is_exiting()) { 2485 clear_external_suspend(); 2486 return ret; 2487 } 2488 2489 assert(_anchor.walkable() || 2490 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2491 "must have walkable stack"); 2492 2493 MonitorLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2494 2495 assert(!this->is_ext_suspended(), 2496 "a thread trying to self-suspend should not already be suspended"); 2497 2498 if (this->is_suspend_equivalent()) { 2499 // If we are self-suspending as a result of the lifting of a 2500 // suspend equivalent condition, then the suspend_equivalent 2501 // flag is not cleared until we set the ext_suspended flag so 2502 // that wait_for_ext_suspend_completion() returns consistent 2503 // results. 2504 this->clear_suspend_equivalent(); 2505 } 2506 2507 // A racing resume may have cancelled us before we grabbed SR_lock 2508 // above. Or another external suspend request could be waiting for us 2509 // by the time we return from SR_lock()->wait(). The thread 2510 // that requested the suspension may already be trying to walk our 2511 // stack and if we return now, we can change the stack out from under 2512 // it. This would be a "bad thing (TM)" and cause the stack walker 2513 // to crash. We stay self-suspended until there are no more pending 2514 // external suspend requests. 2515 while (is_external_suspend()) { 2516 ret++; 2517 this->set_ext_suspended(); 2518 2519 // _ext_suspended flag is cleared by java_resume() 2520 while (is_ext_suspended()) { 2521 ml.wait(); 2522 } 2523 } 2524 return ret; 2525 } 2526 2527 // Helper routine to set up the correct thread state before calling java_suspend_self. 2528 // This is called when regular thread-state transition helpers can't be used because 2529 // we can be in various states, in particular _thread_in_native_trans. 2530 // Because this thread is external suspended the safepoint code will count it as at 2531 // a safepoint, regardless of what its actual current thread-state is. But 2532 // is_ext_suspend_completed() may be waiting to see a thread transition from 2533 // _thread_in_native_trans to _thread_blocked. So we set the thread state directly 2534 // to _thread_blocked. The problem with setting thread state directly is that a 2535 // safepoint could happen just after java_suspend_self() returns after being resumed, 2536 // and the VM thread will see the _thread_blocked state. So we must check for a safepoint 2537 // after restoring the state to make sure we won't leave while a safepoint is in progress. 2538 // However, not all initial-states are allowed when performing a safepoint check, as we 2539 // should never be blocking at a safepoint whilst in those states. Of these 'bad' states 2540 // only _thread_in_native is possible when executing this code (based on our two callers). 2541 // A thread that is _thread_in_native is already safepoint-safe and so it doesn't matter 2542 // whether the VMThread sees the _thread_blocked state, or the _thread_in_native state, 2543 // and so we don't need the explicit safepoint check. 2544 2545 void JavaThread::java_suspend_self_with_safepoint_check() { 2546 assert(this == Thread::current(), "invariant"); 2547 JavaThreadState state = thread_state(); 2548 set_thread_state(_thread_blocked); 2549 java_suspend_self(); 2550 set_thread_state_fence(state); 2551 // Since we are not using a regular thread-state transition helper here, 2552 // we must manually emit the instruction barrier after leaving a safe state. 2553 OrderAccess::cross_modify_fence(); 2554 if (state != _thread_in_native) { 2555 SafepointMechanism::block_if_requested(this); 2556 } 2557 } 2558 2559 #ifdef ASSERT 2560 // Verify the JavaThread has not yet been published in the Threads::list, and 2561 // hence doesn't need protection from concurrent access at this stage. 2562 void JavaThread::verify_not_published() { 2563 // Cannot create a ThreadsListHandle here and check !tlh.includes(this) 2564 // since an unpublished JavaThread doesn't participate in the 2565 // Thread-SMR protocol for keeping a ThreadsList alive. 2566 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!"); 2567 } 2568 #endif 2569 2570 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2571 // progress or when _suspend_flags is non-zero. 2572 // Current thread needs to self-suspend if there is a suspend request and/or 2573 // block if a safepoint is in progress. 2574 // Async exception ISN'T checked. 2575 // Note only the ThreadInVMfromNative transition can call this function 2576 // directly and when thread state is _thread_in_native_trans 2577 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2578 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2579 2580 JavaThread *curJT = JavaThread::current(); 2581 bool do_self_suspend = thread->is_external_suspend(); 2582 2583 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2584 2585 // If JNIEnv proxies are allowed, don't self-suspend if the target 2586 // thread is not the current thread. In older versions of jdbx, jdbx 2587 // threads could call into the VM with another thread's JNIEnv so we 2588 // can be here operating on behalf of a suspended thread (4432884). 2589 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2590 thread->java_suspend_self_with_safepoint_check(); 2591 } else { 2592 SafepointMechanism::block_if_requested(curJT); 2593 } 2594 2595 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);) 2596 } 2597 2598 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2599 // progress or when _suspend_flags is non-zero. 2600 // Current thread needs to self-suspend if there is a suspend request and/or 2601 // block if a safepoint is in progress. 2602 // Also check for pending async exception (not including unsafe access error). 2603 // Note only the native==>VM/Java barriers can call this function and when 2604 // thread state is _thread_in_native_trans. 2605 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2606 check_safepoint_and_suspend_for_native_trans(thread); 2607 2608 if (thread->has_async_exception()) { 2609 // We are in _thread_in_native_trans state, don't handle unsafe 2610 // access error since that may block. 2611 thread->check_and_handle_async_exceptions(false); 2612 } 2613 } 2614 2615 // This is a variant of the normal 2616 // check_special_condition_for_native_trans with slightly different 2617 // semantics for use by critical native wrappers. It does all the 2618 // normal checks but also performs the transition back into 2619 // thread_in_Java state. This is required so that critical natives 2620 // can potentially block and perform a GC if they are the last thread 2621 // exiting the GCLocker. 2622 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2623 check_special_condition_for_native_trans(thread); 2624 2625 // Finish the transition 2626 thread->set_thread_state(_thread_in_Java); 2627 2628 if (thread->do_critical_native_unlock()) { 2629 ThreadInVMfromJavaNoAsyncException tiv(thread); 2630 GCLocker::unlock_critical(thread); 2631 thread->clear_critical_native_unlock(); 2632 } 2633 } 2634 2635 // We need to guarantee the Threads_lock here, since resumes are not 2636 // allowed during safepoint synchronization 2637 // Can only resume from an external suspension 2638 void JavaThread::java_resume() { 2639 assert_locked_or_safepoint(Threads_lock); 2640 2641 // Sanity check: thread is gone, has started exiting or the thread 2642 // was not externally suspended. 2643 ThreadsListHandle tlh; 2644 if (!tlh.includes(this) || is_exiting() || !is_external_suspend()) { 2645 return; 2646 } 2647 2648 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2649 2650 clear_external_suspend(); 2651 2652 if (is_ext_suspended()) { 2653 clear_ext_suspended(); 2654 SR_lock()->notify_all(); 2655 } 2656 } 2657 2658 size_t JavaThread::_stack_red_zone_size = 0; 2659 size_t JavaThread::_stack_yellow_zone_size = 0; 2660 size_t JavaThread::_stack_reserved_zone_size = 0; 2661 size_t JavaThread::_stack_shadow_zone_size = 0; 2662 2663 void JavaThread::create_stack_guard_pages() { 2664 if (!os::uses_stack_guard_pages() || 2665 _stack_guard_state != stack_guard_unused || 2666 (DisablePrimordialThreadGuardPages && os::is_primordial_thread())) { 2667 log_info(os, thread)("Stack guard page creation for thread " 2668 UINTX_FORMAT " disabled", os::current_thread_id()); 2669 return; 2670 } 2671 address low_addr = stack_end(); 2672 size_t len = stack_guard_zone_size(); 2673 2674 assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page"); 2675 assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size"); 2676 2677 int must_commit = os::must_commit_stack_guard_pages(); 2678 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2679 2680 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) { 2681 log_warning(os, thread)("Attempt to allocate stack guard pages failed."); 2682 return; 2683 } 2684 2685 if (os::guard_memory((char *) low_addr, len)) { 2686 _stack_guard_state = stack_guard_enabled; 2687 } else { 2688 log_warning(os, thread)("Attempt to protect stack guard pages failed (" 2689 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2690 if (os::uncommit_memory((char *) low_addr, len)) { 2691 log_warning(os, thread)("Attempt to deallocate stack guard pages failed."); 2692 } 2693 return; 2694 } 2695 2696 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: " 2697 PTR_FORMAT "-" PTR_FORMAT ".", 2698 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2699 } 2700 2701 void JavaThread::remove_stack_guard_pages() { 2702 assert(Thread::current() == this, "from different thread"); 2703 if (_stack_guard_state == stack_guard_unused) return; 2704 address low_addr = stack_end(); 2705 size_t len = stack_guard_zone_size(); 2706 2707 if (os::must_commit_stack_guard_pages()) { 2708 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2709 _stack_guard_state = stack_guard_unused; 2710 } else { 2711 log_warning(os, thread)("Attempt to deallocate stack guard pages failed (" 2712 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2713 return; 2714 } 2715 } else { 2716 if (_stack_guard_state == stack_guard_unused) return; 2717 if (os::unguard_memory((char *) low_addr, len)) { 2718 _stack_guard_state = stack_guard_unused; 2719 } else { 2720 log_warning(os, thread)("Attempt to unprotect stack guard pages failed (" 2721 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2722 return; 2723 } 2724 } 2725 2726 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: " 2727 PTR_FORMAT "-" PTR_FORMAT ".", 2728 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2729 } 2730 2731 void JavaThread::enable_stack_reserved_zone() { 2732 assert(_stack_guard_state == stack_guard_reserved_disabled, "inconsistent state"); 2733 2734 // The base notation is from the stack's point of view, growing downward. 2735 // We need to adjust it to work correctly with guard_memory() 2736 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2737 2738 guarantee(base < stack_base(),"Error calculating stack reserved zone"); 2739 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone"); 2740 2741 if (os::guard_memory((char *) base, stack_reserved_zone_size())) { 2742 _stack_guard_state = stack_guard_enabled; 2743 } else { 2744 warning("Attempt to guard stack reserved zone failed."); 2745 } 2746 enable_register_stack_guard(); 2747 } 2748 2749 void JavaThread::disable_stack_reserved_zone() { 2750 assert(_stack_guard_state == stack_guard_enabled, "inconsistent state"); 2751 2752 // Simply return if called for a thread that does not use guard pages. 2753 if (_stack_guard_state != stack_guard_enabled) return; 2754 2755 // The base notation is from the stack's point of view, growing downward. 2756 // We need to adjust it to work correctly with guard_memory() 2757 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2758 2759 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) { 2760 _stack_guard_state = stack_guard_reserved_disabled; 2761 } else { 2762 warning("Attempt to unguard stack reserved zone failed."); 2763 } 2764 disable_register_stack_guard(); 2765 } 2766 2767 void JavaThread::enable_stack_yellow_reserved_zone() { 2768 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2769 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2770 2771 // The base notation is from the stacks point of view, growing downward. 2772 // We need to adjust it to work correctly with guard_memory() 2773 address base = stack_red_zone_base(); 2774 2775 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2776 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2777 2778 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) { 2779 _stack_guard_state = stack_guard_enabled; 2780 } else { 2781 warning("Attempt to guard stack yellow zone failed."); 2782 } 2783 enable_register_stack_guard(); 2784 } 2785 2786 void JavaThread::disable_stack_yellow_reserved_zone() { 2787 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2788 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled"); 2789 2790 // Simply return if called for a thread that does not use guard pages. 2791 if (_stack_guard_state == stack_guard_unused) return; 2792 2793 // The base notation is from the stacks point of view, growing downward. 2794 // We need to adjust it to work correctly with guard_memory() 2795 address base = stack_red_zone_base(); 2796 2797 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) { 2798 _stack_guard_state = stack_guard_yellow_reserved_disabled; 2799 } else { 2800 warning("Attempt to unguard stack yellow zone failed."); 2801 } 2802 disable_register_stack_guard(); 2803 } 2804 2805 void JavaThread::enable_stack_red_zone() { 2806 // The base notation is from the stacks point of view, growing downward. 2807 // We need to adjust it to work correctly with guard_memory() 2808 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2809 address base = stack_red_zone_base() - stack_red_zone_size(); 2810 2811 guarantee(base < stack_base(), "Error calculating stack red zone"); 2812 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2813 2814 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2815 warning("Attempt to guard stack red zone failed."); 2816 } 2817 } 2818 2819 void JavaThread::disable_stack_red_zone() { 2820 // The base notation is from the stacks point of view, growing downward. 2821 // We need to adjust it to work correctly with guard_memory() 2822 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2823 address base = stack_red_zone_base() - stack_red_zone_size(); 2824 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2825 warning("Attempt to unguard stack red zone failed."); 2826 } 2827 } 2828 2829 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2830 // ignore is there is no stack 2831 if (!has_last_Java_frame()) return; 2832 // traverse the stack frames. Starts from top frame. 2833 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2834 frame* fr = fst.current(); 2835 f(fr, fst.register_map()); 2836 } 2837 } 2838 2839 2840 #ifndef PRODUCT 2841 // Deoptimization 2842 // Function for testing deoptimization 2843 void JavaThread::deoptimize() { 2844 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2845 StackFrameStream fst(this, UseBiasedLocking); 2846 bool deopt = false; // Dump stack only if a deopt actually happens. 2847 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2848 // Iterate over all frames in the thread and deoptimize 2849 for (; !fst.is_done(); fst.next()) { 2850 if (fst.current()->can_be_deoptimized()) { 2851 2852 if (only_at) { 2853 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2854 // consists of comma or carriage return separated numbers so 2855 // search for the current bci in that string. 2856 address pc = fst.current()->pc(); 2857 nmethod* nm = (nmethod*) fst.current()->cb(); 2858 ScopeDesc* sd = nm->scope_desc_at(pc); 2859 char buffer[8]; 2860 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2861 size_t len = strlen(buffer); 2862 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2863 while (found != NULL) { 2864 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2865 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2866 // Check that the bci found is bracketed by terminators. 2867 break; 2868 } 2869 found = strstr(found + 1, buffer); 2870 } 2871 if (!found) { 2872 continue; 2873 } 2874 } 2875 2876 if (DebugDeoptimization && !deopt) { 2877 deopt = true; // One-time only print before deopt 2878 tty->print_cr("[BEFORE Deoptimization]"); 2879 trace_frames(); 2880 trace_stack(); 2881 } 2882 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2883 } 2884 } 2885 2886 if (DebugDeoptimization && deopt) { 2887 tty->print_cr("[AFTER Deoptimization]"); 2888 trace_frames(); 2889 } 2890 } 2891 2892 2893 // Make zombies 2894 void JavaThread::make_zombies() { 2895 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2896 if (fst.current()->can_be_deoptimized()) { 2897 // it is a Java nmethod 2898 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2899 nm->make_not_entrant(); 2900 } 2901 } 2902 } 2903 #endif // PRODUCT 2904 2905 2906 void JavaThread::deoptimized_wrt_marked_nmethods() { 2907 if (!has_last_Java_frame()) return; 2908 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2909 StackFrameStream fst(this, UseBiasedLocking); 2910 for (; !fst.is_done(); fst.next()) { 2911 if (fst.current()->should_be_deoptimized()) { 2912 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2913 } 2914 } 2915 } 2916 2917 2918 // If the caller is a NamedThread, then remember, in the current scope, 2919 // the given JavaThread in its _processed_thread field. 2920 class RememberProcessedThread: public StackObj { 2921 NamedThread* _cur_thr; 2922 public: 2923 RememberProcessedThread(JavaThread* jthr) { 2924 Thread* thread = Thread::current(); 2925 if (thread->is_Named_thread()) { 2926 _cur_thr = (NamedThread *)thread; 2927 _cur_thr->set_processed_thread(jthr); 2928 } else { 2929 _cur_thr = NULL; 2930 } 2931 } 2932 2933 ~RememberProcessedThread() { 2934 if (_cur_thr) { 2935 _cur_thr->set_processed_thread(NULL); 2936 } 2937 } 2938 }; 2939 2940 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 2941 // Verify that the deferred card marks have been flushed. 2942 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2943 2944 // Traverse the GCHandles 2945 Thread::oops_do(f, cf); 2946 2947 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2948 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2949 2950 if (has_last_Java_frame()) { 2951 // Record JavaThread to GC thread 2952 RememberProcessedThread rpt(this); 2953 2954 // traverse the registered growable array 2955 if (_array_for_gc != NULL) { 2956 for (int index = 0; index < _array_for_gc->length(); index++) { 2957 f->do_oop(_array_for_gc->adr_at(index)); 2958 } 2959 } 2960 2961 // Traverse the monitor chunks 2962 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2963 chunk->oops_do(f); 2964 } 2965 2966 // Traverse the execution stack 2967 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2968 fst.current()->oops_do(f, cf, fst.register_map()); 2969 } 2970 } 2971 2972 // callee_target is never live across a gc point so NULL it here should 2973 // it still contain a methdOop. 2974 2975 set_callee_target(NULL); 2976 2977 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2978 // If we have deferred set_locals there might be oops waiting to be 2979 // written 2980 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2981 if (list != NULL) { 2982 for (int i = 0; i < list->length(); i++) { 2983 list->at(i)->oops_do(f); 2984 } 2985 } 2986 2987 // Traverse instance variables at the end since the GC may be moving things 2988 // around using this function 2989 f->do_oop((oop*) &_threadObj); 2990 f->do_oop((oop*) &_vm_result); 2991 f->do_oop((oop*) &_exception_oop); 2992 f->do_oop((oop*) &_pending_async_exception); 2993 2994 if (jvmti_thread_state() != NULL) { 2995 jvmti_thread_state()->oops_do(f); 2996 } 2997 } 2998 2999 #ifdef ASSERT 3000 void JavaThread::verify_states_for_handshake() { 3001 // This checks that the thread has a correct frame state during a handshake. 3002 assert((!has_last_Java_frame() && java_call_counter() == 0) || 3003 (has_last_Java_frame() && java_call_counter() > 0), 3004 "unexpected frame info: has_last_frame=%d, java_call_counter=%d", 3005 has_last_Java_frame(), java_call_counter()); 3006 } 3007 #endif 3008 3009 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 3010 assert((!has_last_Java_frame() && java_call_counter() == 0) || 3011 (has_last_Java_frame() && java_call_counter() > 0), 3012 "unexpected frame info: has_last_frame=%d, java_call_counter=%d", 3013 has_last_Java_frame(), java_call_counter()); 3014 3015 if (has_last_Java_frame()) { 3016 // Traverse the execution stack 3017 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3018 fst.current()->nmethods_do(cf); 3019 } 3020 } 3021 } 3022 3023 void JavaThread::metadata_do(MetadataClosure* f) { 3024 if (has_last_Java_frame()) { 3025 // Traverse the execution stack to call f() on the methods in the stack 3026 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3027 fst.current()->metadata_do(f); 3028 } 3029 } else if (is_Compiler_thread()) { 3030 // need to walk ciMetadata in current compile tasks to keep alive. 3031 CompilerThread* ct = (CompilerThread*)this; 3032 if (ct->env() != NULL) { 3033 ct->env()->metadata_do(f); 3034 } 3035 CompileTask* task = ct->task(); 3036 if (task != NULL) { 3037 task->metadata_do(f); 3038 } 3039 } 3040 } 3041 3042 // Printing 3043 const char* _get_thread_state_name(JavaThreadState _thread_state) { 3044 switch (_thread_state) { 3045 case _thread_uninitialized: return "_thread_uninitialized"; 3046 case _thread_new: return "_thread_new"; 3047 case _thread_new_trans: return "_thread_new_trans"; 3048 case _thread_in_native: return "_thread_in_native"; 3049 case _thread_in_native_trans: return "_thread_in_native_trans"; 3050 case _thread_in_vm: return "_thread_in_vm"; 3051 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 3052 case _thread_in_Java: return "_thread_in_Java"; 3053 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 3054 case _thread_blocked: return "_thread_blocked"; 3055 case _thread_blocked_trans: return "_thread_blocked_trans"; 3056 default: return "unknown thread state"; 3057 } 3058 } 3059 3060 #ifndef PRODUCT 3061 void JavaThread::print_thread_state_on(outputStream *st) const { 3062 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 3063 }; 3064 void JavaThread::print_thread_state() const { 3065 print_thread_state_on(tty); 3066 } 3067 #endif // PRODUCT 3068 3069 // Called by Threads::print() for VM_PrintThreads operation 3070 void JavaThread::print_on(outputStream *st, bool print_extended_info) const { 3071 st->print_raw("\""); 3072 st->print_raw(get_thread_name()); 3073 st->print_raw("\" "); 3074 oop thread_oop = threadObj(); 3075 if (thread_oop != NULL) { 3076 st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop)); 3077 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 3078 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 3079 } 3080 Thread::print_on(st, print_extended_info); 3081 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 3082 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 3083 if (thread_oop != NULL) { 3084 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 3085 } 3086 #ifndef PRODUCT 3087 _safepoint_state->print_on(st); 3088 #endif // PRODUCT 3089 if (is_Compiler_thread()) { 3090 CompileTask *task = ((CompilerThread*)this)->task(); 3091 if (task != NULL) { 3092 st->print(" Compiling: "); 3093 task->print(st, NULL, true, false); 3094 } else { 3095 st->print(" No compile task"); 3096 } 3097 st->cr(); 3098 } 3099 } 3100 3101 void JavaThread::print() const { print_on(tty); } 3102 3103 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const { 3104 st->print("%s", get_thread_name_string(buf, buflen)); 3105 } 3106 3107 // Called by fatal error handler. The difference between this and 3108 // JavaThread::print() is that we can't grab lock or allocate memory. 3109 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 3110 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 3111 oop thread_obj = threadObj(); 3112 if (thread_obj != NULL) { 3113 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 3114 } 3115 st->print(" ["); 3116 st->print("%s", _get_thread_state_name(_thread_state)); 3117 if (osthread()) { 3118 st->print(", id=%d", osthread()->thread_id()); 3119 } 3120 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 3121 p2i(stack_end()), p2i(stack_base())); 3122 st->print("]"); 3123 3124 ThreadsSMRSupport::print_info_on(this, st); 3125 return; 3126 } 3127 3128 // Verification 3129 3130 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 3131 3132 void JavaThread::verify() { 3133 // Verify oops in the thread. 3134 oops_do(&VerifyOopClosure::verify_oop, NULL); 3135 3136 // Verify the stack frames. 3137 frames_do(frame_verify); 3138 } 3139 3140 // CR 6300358 (sub-CR 2137150) 3141 // Most callers of this method assume that it can't return NULL but a 3142 // thread may not have a name whilst it is in the process of attaching to 3143 // the VM - see CR 6412693, and there are places where a JavaThread can be 3144 // seen prior to having it's threadObj set (eg JNI attaching threads and 3145 // if vm exit occurs during initialization). These cases can all be accounted 3146 // for such that this method never returns NULL. 3147 const char* JavaThread::get_thread_name() const { 3148 #ifdef ASSERT 3149 // early safepoints can hit while current thread does not yet have TLS 3150 if (!SafepointSynchronize::is_at_safepoint()) { 3151 Thread *cur = Thread::current(); 3152 if (!(cur->is_Java_thread() && cur == this)) { 3153 // Current JavaThreads are allowed to get their own name without 3154 // the Threads_lock. 3155 assert_locked_or_safepoint(Threads_lock); 3156 } 3157 } 3158 #endif // ASSERT 3159 return get_thread_name_string(); 3160 } 3161 3162 // Returns a non-NULL representation of this thread's name, or a suitable 3163 // descriptive string if there is no set name 3164 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 3165 const char* name_str; 3166 oop thread_obj = threadObj(); 3167 if (thread_obj != NULL) { 3168 oop name = java_lang_Thread::name(thread_obj); 3169 if (name != NULL) { 3170 if (buf == NULL) { 3171 name_str = java_lang_String::as_utf8_string(name); 3172 } else { 3173 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 3174 } 3175 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 3176 name_str = "<no-name - thread is attaching>"; 3177 } else { 3178 name_str = Thread::name(); 3179 } 3180 } else { 3181 name_str = Thread::name(); 3182 } 3183 assert(name_str != NULL, "unexpected NULL thread name"); 3184 return name_str; 3185 } 3186 3187 3188 const char* JavaThread::get_threadgroup_name() const { 3189 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 3190 oop thread_obj = threadObj(); 3191 if (thread_obj != NULL) { 3192 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 3193 if (thread_group != NULL) { 3194 // ThreadGroup.name can be null 3195 return java_lang_ThreadGroup::name(thread_group); 3196 } 3197 } 3198 return NULL; 3199 } 3200 3201 const char* JavaThread::get_parent_name() const { 3202 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 3203 oop thread_obj = threadObj(); 3204 if (thread_obj != NULL) { 3205 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 3206 if (thread_group != NULL) { 3207 oop parent = java_lang_ThreadGroup::parent(thread_group); 3208 if (parent != NULL) { 3209 // ThreadGroup.name can be null 3210 return java_lang_ThreadGroup::name(parent); 3211 } 3212 } 3213 } 3214 return NULL; 3215 } 3216 3217 ThreadPriority JavaThread::java_priority() const { 3218 oop thr_oop = threadObj(); 3219 if (thr_oop == NULL) return NormPriority; // Bootstrapping 3220 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 3221 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 3222 return priority; 3223 } 3224 3225 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 3226 3227 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3228 // Link Java Thread object <-> C++ Thread 3229 3230 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3231 // and put it into a new Handle. The Handle "thread_oop" can then 3232 // be used to pass the C++ thread object to other methods. 3233 3234 // Set the Java level thread object (jthread) field of the 3235 // new thread (a JavaThread *) to C++ thread object using the 3236 // "thread_oop" handle. 3237 3238 // Set the thread field (a JavaThread *) of the 3239 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3240 3241 Handle thread_oop(Thread::current(), 3242 JNIHandles::resolve_non_null(jni_thread)); 3243 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3244 "must be initialized"); 3245 set_threadObj(thread_oop()); 3246 java_lang_Thread::set_thread(thread_oop(), this); 3247 3248 if (prio == NoPriority) { 3249 prio = java_lang_Thread::priority(thread_oop()); 3250 assert(prio != NoPriority, "A valid priority should be present"); 3251 } 3252 3253 // Push the Java priority down to the native thread; needs Threads_lock 3254 Thread::set_priority(this, prio); 3255 3256 // Add the new thread to the Threads list and set it in motion. 3257 // We must have threads lock in order to call Threads::add. 3258 // It is crucial that we do not block before the thread is 3259 // added to the Threads list for if a GC happens, then the java_thread oop 3260 // will not be visited by GC. 3261 Threads::add(this); 3262 } 3263 3264 oop JavaThread::current_park_blocker() { 3265 // Support for JSR-166 locks 3266 oop thread_oop = threadObj(); 3267 if (thread_oop != NULL) { 3268 return java_lang_Thread::park_blocker(thread_oop); 3269 } 3270 return NULL; 3271 } 3272 3273 3274 void JavaThread::print_stack_on(outputStream* st) { 3275 if (!has_last_Java_frame()) return; 3276 ResourceMark rm; 3277 HandleMark hm; 3278 3279 RegisterMap reg_map(this); 3280 vframe* start_vf = last_java_vframe(®_map); 3281 int count = 0; 3282 for (vframe* f = start_vf; f != NULL; f = f->sender()) { 3283 if (f->is_java_frame()) { 3284 javaVFrame* jvf = javaVFrame::cast(f); 3285 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3286 3287 // Print out lock information 3288 if (JavaMonitorsInStackTrace) { 3289 jvf->print_lock_info_on(st, count); 3290 } 3291 } else { 3292 // Ignore non-Java frames 3293 } 3294 3295 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0 3296 count++; 3297 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return; 3298 } 3299 } 3300 3301 3302 // JVMTI PopFrame support 3303 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3304 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3305 if (in_bytes(size_in_bytes) != 0) { 3306 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3307 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3308 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3309 } 3310 } 3311 3312 void* JavaThread::popframe_preserved_args() { 3313 return _popframe_preserved_args; 3314 } 3315 3316 ByteSize JavaThread::popframe_preserved_args_size() { 3317 return in_ByteSize(_popframe_preserved_args_size); 3318 } 3319 3320 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3321 int sz = in_bytes(popframe_preserved_args_size()); 3322 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3323 return in_WordSize(sz / wordSize); 3324 } 3325 3326 void JavaThread::popframe_free_preserved_args() { 3327 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3328 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3329 _popframe_preserved_args = NULL; 3330 _popframe_preserved_args_size = 0; 3331 } 3332 3333 #ifndef PRODUCT 3334 3335 void JavaThread::trace_frames() { 3336 tty->print_cr("[Describe stack]"); 3337 int frame_no = 1; 3338 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3339 tty->print(" %d. ", frame_no++); 3340 fst.current()->print_value_on(tty, this); 3341 tty->cr(); 3342 } 3343 } 3344 3345 class PrintAndVerifyOopClosure: public OopClosure { 3346 protected: 3347 template <class T> inline void do_oop_work(T* p) { 3348 oop obj = RawAccess<>::oop_load(p); 3349 if (obj == NULL) return; 3350 tty->print(INTPTR_FORMAT ": ", p2i(p)); 3351 if (oopDesc::is_oop_or_null(obj)) { 3352 if (obj->is_objArray()) { 3353 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); 3354 } else { 3355 obj->print(); 3356 } 3357 } else { 3358 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); 3359 } 3360 tty->cr(); 3361 } 3362 public: 3363 virtual void do_oop(oop* p) { do_oop_work(p); } 3364 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3365 }; 3366 3367 3368 static void oops_print(frame* f, const RegisterMap *map) { 3369 PrintAndVerifyOopClosure print; 3370 f->print_value(); 3371 f->oops_do(&print, NULL, (RegisterMap*)map); 3372 } 3373 3374 // Print our all the locations that contain oops and whether they are 3375 // valid or not. This useful when trying to find the oldest frame 3376 // where an oop has gone bad since the frame walk is from youngest to 3377 // oldest. 3378 void JavaThread::trace_oops() { 3379 tty->print_cr("[Trace oops]"); 3380 frames_do(oops_print); 3381 } 3382 3383 3384 #ifdef ASSERT 3385 // Print or validate the layout of stack frames 3386 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3387 ResourceMark rm; 3388 PRESERVE_EXCEPTION_MARK; 3389 FrameValues values; 3390 int frame_no = 0; 3391 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3392 fst.current()->describe(values, ++frame_no); 3393 if (depth == frame_no) break; 3394 } 3395 if (validate_only) { 3396 values.validate(); 3397 } else { 3398 tty->print_cr("[Describe stack layout]"); 3399 values.print(this); 3400 } 3401 } 3402 #endif 3403 3404 void JavaThread::trace_stack_from(vframe* start_vf) { 3405 ResourceMark rm; 3406 int vframe_no = 1; 3407 for (vframe* f = start_vf; f; f = f->sender()) { 3408 if (f->is_java_frame()) { 3409 javaVFrame::cast(f)->print_activation(vframe_no++); 3410 } else { 3411 f->print(); 3412 } 3413 if (vframe_no > StackPrintLimit) { 3414 tty->print_cr("...<more frames>..."); 3415 return; 3416 } 3417 } 3418 } 3419 3420 3421 void JavaThread::trace_stack() { 3422 if (!has_last_Java_frame()) return; 3423 ResourceMark rm; 3424 HandleMark hm; 3425 RegisterMap reg_map(this); 3426 trace_stack_from(last_java_vframe(®_map)); 3427 } 3428 3429 3430 #endif // PRODUCT 3431 3432 3433 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3434 assert(reg_map != NULL, "a map must be given"); 3435 frame f = last_frame(); 3436 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3437 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3438 } 3439 return NULL; 3440 } 3441 3442 3443 Klass* JavaThread::security_get_caller_class(int depth) { 3444 vframeStream vfst(this); 3445 vfst.security_get_caller_frame(depth); 3446 if (!vfst.at_end()) { 3447 return vfst.method()->method_holder(); 3448 } 3449 return NULL; 3450 } 3451 3452 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3453 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3454 CompileBroker::compiler_thread_loop(); 3455 } 3456 3457 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3458 NMethodSweeper::sweeper_loop(); 3459 } 3460 3461 // Create a CompilerThread 3462 CompilerThread::CompilerThread(CompileQueue* queue, 3463 CompilerCounters* counters) 3464 : JavaThread(&compiler_thread_entry) { 3465 _env = NULL; 3466 _log = NULL; 3467 _task = NULL; 3468 _queue = queue; 3469 _counters = counters; 3470 _buffer_blob = NULL; 3471 _compiler = NULL; 3472 3473 // Compiler uses resource area for compilation, let's bias it to mtCompiler 3474 resource_area()->bias_to(mtCompiler); 3475 3476 #ifndef PRODUCT 3477 _ideal_graph_printer = NULL; 3478 #endif 3479 } 3480 3481 CompilerThread::~CompilerThread() { 3482 // Delete objects which were allocated on heap. 3483 delete _counters; 3484 } 3485 3486 bool CompilerThread::can_call_java() const { 3487 return _compiler != NULL && _compiler->is_jvmci(); 3488 } 3489 3490 // Create sweeper thread 3491 CodeCacheSweeperThread::CodeCacheSweeperThread() 3492 : JavaThread(&sweeper_thread_entry) { 3493 _scanned_compiled_method = NULL; 3494 } 3495 3496 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 3497 JavaThread::oops_do(f, cf); 3498 if (_scanned_compiled_method != NULL && cf != NULL) { 3499 // Safepoints can occur when the sweeper is scanning an nmethod so 3500 // process it here to make sure it isn't unloaded in the middle of 3501 // a scan. 3502 cf->do_code_blob(_scanned_compiled_method); 3503 } 3504 } 3505 3506 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) { 3507 JavaThread::nmethods_do(cf); 3508 if (_scanned_compiled_method != NULL && cf != NULL) { 3509 // Safepoints can occur when the sweeper is scanning an nmethod so 3510 // process it here to make sure it isn't unloaded in the middle of 3511 // a scan. 3512 cf->do_code_blob(_scanned_compiled_method); 3513 } 3514 } 3515 3516 3517 // ======= Threads ======== 3518 3519 // The Threads class links together all active threads, and provides 3520 // operations over all threads. It is protected by the Threads_lock, 3521 // which is also used in other global contexts like safepointing. 3522 // ThreadsListHandles are used to safely perform operations on one 3523 // or more threads without the risk of the thread exiting during the 3524 // operation. 3525 // 3526 // Note: The Threads_lock is currently more widely used than we 3527 // would like. We are actively migrating Threads_lock uses to other 3528 // mechanisms in order to reduce Threads_lock contention. 3529 3530 int Threads::_number_of_threads = 0; 3531 int Threads::_number_of_non_daemon_threads = 0; 3532 int Threads::_return_code = 0; 3533 uintx Threads::_thread_claim_token = 1; // Never zero. 3534 size_t JavaThread::_stack_size_at_create = 0; 3535 3536 #ifdef ASSERT 3537 bool Threads::_vm_complete = false; 3538 #endif 3539 3540 static inline void *prefetch_and_load_ptr(void **addr, intx prefetch_interval) { 3541 Prefetch::read((void*)addr, prefetch_interval); 3542 return *addr; 3543 } 3544 3545 // Possibly the ugliest for loop the world has seen. C++ does not allow 3546 // multiple types in the declaration section of the for loop. In this case 3547 // we are only dealing with pointers and hence can cast them. It looks ugly 3548 // but macros are ugly and therefore it's fine to make things absurdly ugly. 3549 #define DO_JAVA_THREADS(LIST, X) \ 3550 for (JavaThread *MACRO_scan_interval = (JavaThread*)(uintptr_t)PrefetchScanIntervalInBytes, \ 3551 *MACRO_list = (JavaThread*)(LIST), \ 3552 **MACRO_end = ((JavaThread**)((ThreadsList*)MACRO_list)->threads()) + ((ThreadsList*)MACRO_list)->length(), \ 3553 **MACRO_current_p = (JavaThread**)((ThreadsList*)MACRO_list)->threads(), \ 3554 *X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval); \ 3555 MACRO_current_p != MACRO_end; \ 3556 MACRO_current_p++, \ 3557 X = (JavaThread*)prefetch_and_load_ptr((void**)MACRO_current_p, (intx)MACRO_scan_interval)) 3558 3559 // All JavaThreads 3560 #define ALL_JAVA_THREADS(X) DO_JAVA_THREADS(ThreadsSMRSupport::get_java_thread_list(), X) 3561 3562 // All NonJavaThreads (i.e., every non-JavaThread in the system). 3563 void Threads::non_java_threads_do(ThreadClosure* tc) { 3564 NoSafepointVerifier nsv(!SafepointSynchronize::is_at_safepoint(), false); 3565 for (NonJavaThread::Iterator njti; !njti.end(); njti.step()) { 3566 tc->do_thread(njti.current()); 3567 } 3568 } 3569 3570 // All JavaThreads 3571 void Threads::java_threads_do(ThreadClosure* tc) { 3572 assert_locked_or_safepoint(Threads_lock); 3573 // ALL_JAVA_THREADS iterates through all JavaThreads. 3574 ALL_JAVA_THREADS(p) { 3575 tc->do_thread(p); 3576 } 3577 } 3578 3579 void Threads::java_threads_and_vm_thread_do(ThreadClosure* tc) { 3580 assert_locked_or_safepoint(Threads_lock); 3581 java_threads_do(tc); 3582 tc->do_thread(VMThread::vm_thread()); 3583 } 3584 3585 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system). 3586 void Threads::threads_do(ThreadClosure* tc) { 3587 assert_locked_or_safepoint(Threads_lock); 3588 java_threads_do(tc); 3589 non_java_threads_do(tc); 3590 } 3591 3592 void Threads::possibly_parallel_threads_do(bool is_par, ThreadClosure* tc) { 3593 uintx claim_token = Threads::thread_claim_token(); 3594 ALL_JAVA_THREADS(p) { 3595 if (p->claim_threads_do(is_par, claim_token)) { 3596 tc->do_thread(p); 3597 } 3598 } 3599 VMThread* vmt = VMThread::vm_thread(); 3600 if (vmt->claim_threads_do(is_par, claim_token)) { 3601 tc->do_thread(vmt); 3602 } 3603 } 3604 3605 // The system initialization in the library has three phases. 3606 // 3607 // Phase 1: java.lang.System class initialization 3608 // java.lang.System is a primordial class loaded and initialized 3609 // by the VM early during startup. java.lang.System.<clinit> 3610 // only does registerNatives and keeps the rest of the class 3611 // initialization work later until thread initialization completes. 3612 // 3613 // System.initPhase1 initializes the system properties, the static 3614 // fields in, out, and err. Set up java signal handlers, OS-specific 3615 // system settings, and thread group of the main thread. 3616 static void call_initPhase1(TRAPS) { 3617 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3618 JavaValue result(T_VOID); 3619 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(), 3620 vmSymbols::void_method_signature(), CHECK); 3621 } 3622 3623 // Phase 2. Module system initialization 3624 // This will initialize the module system. Only java.base classes 3625 // can be loaded until phase 2 completes. 3626 // 3627 // Call System.initPhase2 after the compiler initialization and jsr292 3628 // classes get initialized because module initialization runs a lot of java 3629 // code, that for performance reasons, should be compiled. Also, this will 3630 // enable the startup code to use lambda and other language features in this 3631 // phase and onward. 3632 // 3633 // After phase 2, The VM will begin search classes from -Xbootclasspath/a. 3634 static void call_initPhase2(TRAPS) { 3635 TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime)); 3636 3637 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3638 3639 JavaValue result(T_INT); 3640 JavaCallArguments args; 3641 args.push_int(DisplayVMOutputToStderr); 3642 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown 3643 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(), 3644 vmSymbols::boolean_boolean_int_signature(), &args, CHECK); 3645 if (result.get_jint() != JNI_OK) { 3646 vm_exit_during_initialization(); // no message or exception 3647 } 3648 3649 universe_post_module_init(); 3650 } 3651 3652 // Phase 3. final setup - set security manager, system class loader and TCCL 3653 // 3654 // This will instantiate and set the security manager, set the system class 3655 // loader as well as the thread context class loader. The security manager 3656 // and system class loader may be a custom class loaded from -Xbootclasspath/a, 3657 // other modules or the application's classpath. 3658 static void call_initPhase3(TRAPS) { 3659 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3660 JavaValue result(T_VOID); 3661 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(), 3662 vmSymbols::void_method_signature(), CHECK); 3663 } 3664 3665 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3666 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime)); 3667 3668 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3669 create_vm_init_libraries(); 3670 } 3671 3672 initialize_class(vmSymbols::java_lang_String(), CHECK); 3673 3674 // Inject CompactStrings value after the static initializers for String ran. 3675 java_lang_String::set_compact_strings(CompactStrings); 3676 3677 // Initialize java_lang.System (needed before creating the thread) 3678 initialize_class(vmSymbols::java_lang_System(), CHECK); 3679 // The VM creates & returns objects of this class. Make sure it's initialized. 3680 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3681 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3682 Handle thread_group = create_initial_thread_group(CHECK); 3683 Universe::set_main_thread_group(thread_group()); 3684 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3685 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3686 main_thread->set_threadObj(thread_object); 3687 3688 // Set thread status to running since main thread has 3689 // been started and running. 3690 java_lang_Thread::set_thread_status(thread_object, 3691 java_lang_Thread::RUNNABLE); 3692 3693 // The VM creates objects of this class. 3694 initialize_class(vmSymbols::java_lang_Module(), CHECK); 3695 3696 #ifdef ASSERT 3697 InstanceKlass *k = SystemDictionary::UnsafeConstants_klass(); 3698 assert(k->is_not_initialized(), "UnsafeConstants should not already be initialized"); 3699 #endif 3700 3701 // initialize the hardware-specific constants needed by Unsafe 3702 initialize_class(vmSymbols::jdk_internal_misc_UnsafeConstants(), CHECK); 3703 jdk_internal_misc_UnsafeConstants::set_unsafe_constants(); 3704 3705 // The VM preresolves methods to these classes. Make sure that they get initialized 3706 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3707 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3708 3709 // Phase 1 of the system initialization in the library, java.lang.System class initialization 3710 call_initPhase1(CHECK); 3711 3712 // get the Java runtime name after java.lang.System is initialized 3713 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3714 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3715 3716 // an instance of OutOfMemory exception has been allocated earlier 3717 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3718 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3719 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3720 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3721 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3722 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3723 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3724 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3725 3726 // Eager box cache initialization only if AOT is on and any library is loaded. 3727 AOTLoader::initialize_box_caches(CHECK); 3728 } 3729 3730 void Threads::initialize_jsr292_core_classes(TRAPS) { 3731 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime)); 3732 3733 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3734 initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK); 3735 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3736 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3737 } 3738 3739 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3740 extern void JDK_Version_init(); 3741 3742 // Preinitialize version info. 3743 VM_Version::early_initialize(); 3744 3745 // Check version 3746 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3747 3748 // Initialize library-based TLS 3749 ThreadLocalStorage::init(); 3750 3751 // Initialize the output stream module 3752 ostream_init(); 3753 3754 // Process java launcher properties. 3755 Arguments::process_sun_java_launcher_properties(args); 3756 3757 // Initialize the os module 3758 os::init(); 3759 3760 // Record VM creation timing statistics 3761 TraceVmCreationTime create_vm_timer; 3762 create_vm_timer.start(); 3763 3764 // Initialize system properties. 3765 Arguments::init_system_properties(); 3766 3767 // So that JDK version can be used as a discriminator when parsing arguments 3768 JDK_Version_init(); 3769 3770 // Update/Initialize System properties after JDK version number is known 3771 Arguments::init_version_specific_system_properties(); 3772 3773 // Make sure to initialize log configuration *before* parsing arguments 3774 LogConfiguration::initialize(create_vm_timer.begin_time()); 3775 3776 // Parse arguments 3777 // Note: this internally calls os::init_container_support() 3778 jint parse_result = Arguments::parse(args); 3779 if (parse_result != JNI_OK) return parse_result; 3780 3781 os::init_before_ergo(); 3782 3783 jint ergo_result = Arguments::apply_ergo(); 3784 if (ergo_result != JNI_OK) return ergo_result; 3785 3786 // Final check of all ranges after ergonomics which may change values. 3787 if (!JVMFlagRangeList::check_ranges()) { 3788 return JNI_EINVAL; 3789 } 3790 3791 // Final check of all 'AfterErgo' constraints after ergonomics which may change values. 3792 bool constraint_result = JVMFlagConstraintList::check_constraints(JVMFlagConstraint::AfterErgo); 3793 if (!constraint_result) { 3794 return JNI_EINVAL; 3795 } 3796 3797 JVMFlagWriteableList::mark_startup(); 3798 3799 if (PauseAtStartup) { 3800 os::pause(); 3801 } 3802 3803 HOTSPOT_VM_INIT_BEGIN(); 3804 3805 // Timing (must come after argument parsing) 3806 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime)); 3807 3808 // Initialize the os module after parsing the args 3809 jint os_init_2_result = os::init_2(); 3810 if (os_init_2_result != JNI_OK) return os_init_2_result; 3811 3812 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT 3813 // Initialize assert poison page mechanism. 3814 if (ShowRegistersOnAssert) { 3815 initialize_assert_poison(); 3816 } 3817 #endif // CAN_SHOW_REGISTERS_ON_ASSERT 3818 3819 SafepointMechanism::initialize(); 3820 3821 jint adjust_after_os_result = Arguments::adjust_after_os(); 3822 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3823 3824 // Initialize output stream logging 3825 ostream_init_log(); 3826 3827 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3828 // Must be before create_vm_init_agents() 3829 if (Arguments::init_libraries_at_startup()) { 3830 convert_vm_init_libraries_to_agents(); 3831 } 3832 3833 // Launch -agentlib/-agentpath and converted -Xrun agents 3834 if (Arguments::init_agents_at_startup()) { 3835 create_vm_init_agents(); 3836 } 3837 3838 // Initialize Threads state 3839 _number_of_threads = 0; 3840 _number_of_non_daemon_threads = 0; 3841 3842 // Initialize global data structures and create system classes in heap 3843 vm_init_globals(); 3844 3845 #if INCLUDE_JVMCI 3846 if (JVMCICounterSize > 0) { 3847 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtJVMCI); 3848 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize); 3849 } else { 3850 JavaThread::_jvmci_old_thread_counters = NULL; 3851 } 3852 #endif // INCLUDE_JVMCI 3853 3854 // Attach the main thread to this os thread 3855 JavaThread* main_thread = new JavaThread(); 3856 main_thread->set_thread_state(_thread_in_vm); 3857 main_thread->initialize_thread_current(); 3858 // must do this before set_active_handles 3859 main_thread->record_stack_base_and_size(); 3860 main_thread->register_thread_stack_with_NMT(); 3861 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3862 3863 if (!main_thread->set_as_starting_thread()) { 3864 vm_shutdown_during_initialization( 3865 "Failed necessary internal allocation. Out of swap space"); 3866 main_thread->smr_delete(); 3867 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3868 return JNI_ENOMEM; 3869 } 3870 3871 // Enable guard page *after* os::create_main_thread(), otherwise it would 3872 // crash Linux VM, see notes in os_linux.cpp. 3873 main_thread->create_stack_guard_pages(); 3874 3875 // Initialize Java-Level synchronization subsystem 3876 ObjectMonitor::Initialize(); 3877 3878 // Initialize global modules 3879 jint status = init_globals(); 3880 if (status != JNI_OK) { 3881 main_thread->smr_delete(); 3882 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3883 return status; 3884 } 3885 3886 JFR_ONLY(Jfr::on_vm_init();) 3887 3888 // Should be done after the heap is fully created 3889 main_thread->cache_global_variables(); 3890 3891 HandleMark hm; 3892 3893 { MutexLocker mu(Threads_lock); 3894 Threads::add(main_thread); 3895 } 3896 3897 // Any JVMTI raw monitors entered in onload will transition into 3898 // real raw monitor. VM is setup enough here for raw monitor enter. 3899 JvmtiExport::transition_pending_onload_raw_monitors(); 3900 3901 // Create the VMThread 3902 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime)); 3903 3904 VMThread::create(); 3905 Thread* vmthread = VMThread::vm_thread(); 3906 3907 if (!os::create_thread(vmthread, os::vm_thread)) { 3908 vm_exit_during_initialization("Cannot create VM thread. " 3909 "Out of system resources."); 3910 } 3911 3912 // Wait for the VM thread to become ready, and VMThread::run to initialize 3913 // Monitors can have spurious returns, must always check another state flag 3914 { 3915 MonitorLocker ml(Notify_lock); 3916 os::start_thread(vmthread); 3917 while (vmthread->active_handles() == NULL) { 3918 ml.wait(); 3919 } 3920 } 3921 } 3922 3923 assert(Universe::is_fully_initialized(), "not initialized"); 3924 if (VerifyDuringStartup) { 3925 // Make sure we're starting with a clean slate. 3926 VM_Verify verify_op; 3927 VMThread::execute(&verify_op); 3928 } 3929 3930 // We need this to update the java.vm.info property in case any flags used 3931 // to initially define it have been changed. This is needed for both CDS and 3932 // AOT, since UseSharedSpaces and UseAOT may be changed after java.vm.info 3933 // is initially computed. See Abstract_VM_Version::vm_info_string(). 3934 // This update must happen before we initialize the java classes, but 3935 // after any initialization logic that might modify the flags. 3936 Arguments::update_vm_info_property(VM_Version::vm_info_string()); 3937 3938 Thread* THREAD = Thread::current(); 3939 3940 // Always call even when there are not JVMTI environments yet, since environments 3941 // may be attached late and JVMTI must track phases of VM execution 3942 JvmtiExport::enter_early_start_phase(); 3943 3944 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3945 JvmtiExport::post_early_vm_start(); 3946 3947 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3948 3949 quicken_jni_functions(); 3950 3951 // No more stub generation allowed after that point. 3952 StubCodeDesc::freeze(); 3953 3954 // Set flag that basic initialization has completed. Used by exceptions and various 3955 // debug stuff, that does not work until all basic classes have been initialized. 3956 set_init_completed(); 3957 3958 LogConfiguration::post_initialize(); 3959 Metaspace::post_initialize(); 3960 3961 HOTSPOT_VM_INIT_END(); 3962 3963 // record VM initialization completion time 3964 #if INCLUDE_MANAGEMENT 3965 Management::record_vm_init_completed(); 3966 #endif // INCLUDE_MANAGEMENT 3967 3968 // Signal Dispatcher needs to be started before VMInit event is posted 3969 os::initialize_jdk_signal_support(CHECK_JNI_ERR); 3970 3971 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3972 if (!DisableAttachMechanism) { 3973 AttachListener::vm_start(); 3974 if (StartAttachListener || AttachListener::init_at_startup()) { 3975 AttachListener::init(); 3976 } 3977 } 3978 3979 // Launch -Xrun agents 3980 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3981 // back-end can launch with -Xdebug -Xrunjdwp. 3982 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3983 create_vm_init_libraries(); 3984 } 3985 3986 if (CleanChunkPoolAsync) { 3987 Chunk::start_chunk_pool_cleaner_task(); 3988 } 3989 3990 3991 // initialize compiler(s) 3992 #if defined(COMPILER1) || COMPILER2_OR_JVMCI 3993 #if INCLUDE_JVMCI 3994 bool force_JVMCI_intialization = false; 3995 if (EnableJVMCI) { 3996 // Initialize JVMCI eagerly when it is explicitly requested. 3997 // Or when JVMCILibDumpJNIConfig or JVMCIPrintProperties is enabled. 3998 force_JVMCI_intialization = EagerJVMCI || JVMCIPrintProperties || JVMCILibDumpJNIConfig; 3999 4000 if (!force_JVMCI_intialization) { 4001 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking 4002 // compilations via JVMCI will not actually block until JVMCI is initialized. 4003 force_JVMCI_intialization = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation); 4004 } 4005 } 4006 #endif 4007 CompileBroker::compilation_init_phase1(CHECK_JNI_ERR); 4008 // Postpone completion of compiler initialization to after JVMCI 4009 // is initialized to avoid timeouts of blocking compilations. 4010 if (JVMCI_ONLY(!force_JVMCI_intialization) NOT_JVMCI(true)) { 4011 CompileBroker::compilation_init_phase2(); 4012 } 4013 #endif 4014 4015 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 4016 // It is done after compilers are initialized, because otherwise compilations of 4017 // signature polymorphic MH intrinsics can be missed 4018 // (see SystemDictionary::find_method_handle_intrinsic). 4019 initialize_jsr292_core_classes(CHECK_JNI_ERR); 4020 4021 // This will initialize the module system. Only java.base classes can be 4022 // loaded until phase 2 completes 4023 call_initPhase2(CHECK_JNI_ERR); 4024 4025 // Always call even when there are not JVMTI environments yet, since environments 4026 // may be attached late and JVMTI must track phases of VM execution 4027 JvmtiExport::enter_start_phase(); 4028 4029 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 4030 JvmtiExport::post_vm_start(); 4031 4032 // Final system initialization including security manager and system class loader 4033 call_initPhase3(CHECK_JNI_ERR); 4034 4035 // cache the system and platform class loaders 4036 SystemDictionary::compute_java_loaders(CHECK_JNI_ERR); 4037 4038 #if INCLUDE_CDS 4039 // capture the module path info from the ModuleEntryTable 4040 ClassLoader::initialize_module_path(THREAD); 4041 #endif 4042 4043 #if INCLUDE_JVMCI 4044 if (force_JVMCI_intialization) { 4045 JVMCI::initialize_compiler(CHECK_JNI_ERR); 4046 CompileBroker::compilation_init_phase2(); 4047 } 4048 #endif 4049 4050 // Always call even when there are not JVMTI environments yet, since environments 4051 // may be attached late and JVMTI must track phases of VM execution 4052 JvmtiExport::enter_live_phase(); 4053 4054 // Make perfmemory accessible 4055 PerfMemory::set_accessible(true); 4056 4057 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 4058 JvmtiExport::post_vm_initialized(); 4059 4060 JFR_ONLY(Jfr::on_vm_start();) 4061 4062 #if INCLUDE_MANAGEMENT 4063 Management::initialize(THREAD); 4064 4065 if (HAS_PENDING_EXCEPTION) { 4066 // management agent fails to start possibly due to 4067 // configuration problem and is responsible for printing 4068 // stack trace if appropriate. Simply exit VM. 4069 vm_exit(1); 4070 } 4071 #endif // INCLUDE_MANAGEMENT 4072 4073 if (MemProfiling) MemProfiler::engage(); 4074 StatSampler::engage(); 4075 if (CheckJNICalls) JniPeriodicChecker::engage(); 4076 4077 BiasedLocking::init(); 4078 4079 #if INCLUDE_RTM_OPT 4080 RTMLockingCounters::init(); 4081 #endif 4082 4083 call_postVMInitHook(THREAD); 4084 // The Java side of PostVMInitHook.run must deal with all 4085 // exceptions and provide means of diagnosis. 4086 if (HAS_PENDING_EXCEPTION) { 4087 CLEAR_PENDING_EXCEPTION; 4088 } 4089 4090 { 4091 MutexLocker ml(PeriodicTask_lock); 4092 // Make sure the WatcherThread can be started by WatcherThread::start() 4093 // or by dynamic enrollment. 4094 WatcherThread::make_startable(); 4095 // Start up the WatcherThread if there are any periodic tasks 4096 // NOTE: All PeriodicTasks should be registered by now. If they 4097 // aren't, late joiners might appear to start slowly (we might 4098 // take a while to process their first tick). 4099 if (PeriodicTask::num_tasks() > 0) { 4100 WatcherThread::start(); 4101 } 4102 } 4103 4104 create_vm_timer.end(); 4105 #ifdef ASSERT 4106 _vm_complete = true; 4107 #endif 4108 4109 if (DumpSharedSpaces) { 4110 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 4111 ShouldNotReachHere(); 4112 } 4113 4114 return JNI_OK; 4115 } 4116 4117 // type for the Agent_OnLoad and JVM_OnLoad entry points 4118 extern "C" { 4119 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 4120 } 4121 // Find a command line agent library and return its entry point for 4122 // -agentlib: -agentpath: -Xrun 4123 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 4124 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 4125 const char *on_load_symbols[], 4126 size_t num_symbol_entries) { 4127 OnLoadEntry_t on_load_entry = NULL; 4128 void *library = NULL; 4129 4130 if (!agent->valid()) { 4131 char buffer[JVM_MAXPATHLEN]; 4132 char ebuf[1024] = ""; 4133 const char *name = agent->name(); 4134 const char *msg = "Could not find agent library "; 4135 4136 // First check to see if agent is statically linked into executable 4137 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 4138 library = agent->os_lib(); 4139 } else if (agent->is_absolute_path()) { 4140 library = os::dll_load(name, ebuf, sizeof ebuf); 4141 if (library == NULL) { 4142 const char *sub_msg = " in absolute path, with error: "; 4143 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 4144 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 4145 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 4146 // If we can't find the agent, exit. 4147 vm_exit_during_initialization(buf, NULL); 4148 FREE_C_HEAP_ARRAY(char, buf); 4149 } 4150 } else { 4151 // Try to load the agent from the standard dll directory 4152 if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(), 4153 name)) { 4154 library = os::dll_load(buffer, ebuf, sizeof ebuf); 4155 } 4156 if (library == NULL) { // Try the library path directory. 4157 if (os::dll_build_name(buffer, sizeof(buffer), name)) { 4158 library = os::dll_load(buffer, ebuf, sizeof ebuf); 4159 } 4160 if (library == NULL) { 4161 const char *sub_msg = " on the library path, with error: "; 4162 const char *sub_msg2 = "\nModule java.instrument may be missing from runtime image."; 4163 4164 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + 4165 strlen(ebuf) + strlen(sub_msg2) + 1; 4166 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 4167 if (!agent->is_instrument_lib()) { 4168 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 4169 } else { 4170 jio_snprintf(buf, len, "%s%s%s%s%s", msg, name, sub_msg, ebuf, sub_msg2); 4171 } 4172 // If we can't find the agent, exit. 4173 vm_exit_during_initialization(buf, NULL); 4174 FREE_C_HEAP_ARRAY(char, buf); 4175 } 4176 } 4177 } 4178 agent->set_os_lib(library); 4179 agent->set_valid(); 4180 } 4181 4182 // Find the OnLoad function. 4183 on_load_entry = 4184 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 4185 false, 4186 on_load_symbols, 4187 num_symbol_entries)); 4188 return on_load_entry; 4189 } 4190 4191 // Find the JVM_OnLoad entry point 4192 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 4193 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 4194 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 4195 } 4196 4197 // Find the Agent_OnLoad entry point 4198 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 4199 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 4200 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 4201 } 4202 4203 // For backwards compatibility with -Xrun 4204 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 4205 // treated like -agentpath: 4206 // Must be called before agent libraries are created 4207 void Threads::convert_vm_init_libraries_to_agents() { 4208 AgentLibrary* agent; 4209 AgentLibrary* next; 4210 4211 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 4212 next = agent->next(); // cache the next agent now as this agent may get moved off this list 4213 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 4214 4215 // If there is an JVM_OnLoad function it will get called later, 4216 // otherwise see if there is an Agent_OnLoad 4217 if (on_load_entry == NULL) { 4218 on_load_entry = lookup_agent_on_load(agent); 4219 if (on_load_entry != NULL) { 4220 // switch it to the agent list -- so that Agent_OnLoad will be called, 4221 // JVM_OnLoad won't be attempted and Agent_OnUnload will 4222 Arguments::convert_library_to_agent(agent); 4223 } else { 4224 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 4225 } 4226 } 4227 } 4228 } 4229 4230 // Create agents for -agentlib: -agentpath: and converted -Xrun 4231 // Invokes Agent_OnLoad 4232 // Called very early -- before JavaThreads exist 4233 void Threads::create_vm_init_agents() { 4234 extern struct JavaVM_ main_vm; 4235 AgentLibrary* agent; 4236 4237 JvmtiExport::enter_onload_phase(); 4238 4239 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 4240 // CDS dumping does not support native JVMTI agent. 4241 // CDS dumping supports Java agent if the AllowArchivingWithJavaAgent diagnostic option is specified. 4242 if (DumpSharedSpaces || DynamicDumpSharedSpaces) { 4243 if(!agent->is_instrument_lib()) { 4244 vm_exit_during_cds_dumping("CDS dumping does not support native JVMTI agent, name", agent->name()); 4245 } else if (!AllowArchivingWithJavaAgent) { 4246 vm_exit_during_cds_dumping( 4247 "Must enable AllowArchivingWithJavaAgent in order to run Java agent during CDS dumping"); 4248 } 4249 } 4250 4251 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 4252 4253 if (on_load_entry != NULL) { 4254 // Invoke the Agent_OnLoad function 4255 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 4256 if (err != JNI_OK) { 4257 vm_exit_during_initialization("agent library failed to init", agent->name()); 4258 } 4259 } else { 4260 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 4261 } 4262 } 4263 4264 JvmtiExport::enter_primordial_phase(); 4265 } 4266 4267 extern "C" { 4268 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 4269 } 4270 4271 void Threads::shutdown_vm_agents() { 4272 // Send any Agent_OnUnload notifications 4273 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 4274 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 4275 extern struct JavaVM_ main_vm; 4276 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 4277 4278 // Find the Agent_OnUnload function. 4279 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 4280 os::find_agent_function(agent, 4281 false, 4282 on_unload_symbols, 4283 num_symbol_entries)); 4284 4285 // Invoke the Agent_OnUnload function 4286 if (unload_entry != NULL) { 4287 JavaThread* thread = JavaThread::current(); 4288 ThreadToNativeFromVM ttn(thread); 4289 HandleMark hm(thread); 4290 (*unload_entry)(&main_vm); 4291 } 4292 } 4293 } 4294 4295 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 4296 // Invokes JVM_OnLoad 4297 void Threads::create_vm_init_libraries() { 4298 extern struct JavaVM_ main_vm; 4299 AgentLibrary* agent; 4300 4301 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 4302 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 4303 4304 if (on_load_entry != NULL) { 4305 // Invoke the JVM_OnLoad function 4306 JavaThread* thread = JavaThread::current(); 4307 ThreadToNativeFromVM ttn(thread); 4308 HandleMark hm(thread); 4309 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 4310 if (err != JNI_OK) { 4311 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 4312 } 4313 } else { 4314 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 4315 } 4316 } 4317 } 4318 4319 4320 // Last thread running calls java.lang.Shutdown.shutdown() 4321 void JavaThread::invoke_shutdown_hooks() { 4322 HandleMark hm(this); 4323 4324 // We could get here with a pending exception, if so clear it now. 4325 if (this->has_pending_exception()) { 4326 this->clear_pending_exception(); 4327 } 4328 4329 EXCEPTION_MARK; 4330 Klass* shutdown_klass = 4331 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 4332 THREAD); 4333 if (shutdown_klass != NULL) { 4334 // SystemDictionary::resolve_or_null will return null if there was 4335 // an exception. If we cannot load the Shutdown class, just don't 4336 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 4337 // won't be run. Note that if a shutdown hook was registered, 4338 // the Shutdown class would have already been loaded 4339 // (Runtime.addShutdownHook will load it). 4340 JavaValue result(T_VOID); 4341 JavaCalls::call_static(&result, 4342 shutdown_klass, 4343 vmSymbols::shutdown_name(), 4344 vmSymbols::void_method_signature(), 4345 THREAD); 4346 } 4347 CLEAR_PENDING_EXCEPTION; 4348 } 4349 4350 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 4351 // the program falls off the end of main(). Another VM exit path is through 4352 // vm_exit() when the program calls System.exit() to return a value or when 4353 // there is a serious error in VM. The two shutdown paths are not exactly 4354 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 4355 // and VM_Exit op at VM level. 4356 // 4357 // Shutdown sequence: 4358 // + Shutdown native memory tracking if it is on 4359 // + Wait until we are the last non-daemon thread to execute 4360 // <-- every thing is still working at this moment --> 4361 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 4362 // shutdown hooks 4363 // + Call before_exit(), prepare for VM exit 4364 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 4365 // currently the only user of this mechanism is File.deleteOnExit()) 4366 // > stop StatSampler, watcher thread, CMS threads, 4367 // post thread end and vm death events to JVMTI, 4368 // stop signal thread 4369 // + Call JavaThread::exit(), it will: 4370 // > release JNI handle blocks, remove stack guard pages 4371 // > remove this thread from Threads list 4372 // <-- no more Java code from this thread after this point --> 4373 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 4374 // the compiler threads at safepoint 4375 // <-- do not use anything that could get blocked by Safepoint --> 4376 // + Disable tracing at JNI/JVM barriers 4377 // + Set _vm_exited flag for threads that are still running native code 4378 // + Call exit_globals() 4379 // > deletes tty 4380 // > deletes PerfMemory resources 4381 // + Delete this thread 4382 // + Return to caller 4383 4384 bool Threads::destroy_vm() { 4385 JavaThread* thread = JavaThread::current(); 4386 4387 #ifdef ASSERT 4388 _vm_complete = false; 4389 #endif 4390 // Wait until we are the last non-daemon thread to execute 4391 { MonitorLocker nu(Threads_lock); 4392 while (Threads::number_of_non_daemon_threads() > 1) 4393 // This wait should make safepoint checks, wait without a timeout, 4394 // and wait as a suspend-equivalent condition. 4395 nu.wait(0, Mutex::_as_suspend_equivalent_flag); 4396 } 4397 4398 EventShutdown e; 4399 if (e.should_commit()) { 4400 e.set_reason("No remaining non-daemon Java threads"); 4401 e.commit(); 4402 } 4403 4404 // Hang forever on exit if we are reporting an error. 4405 if (ShowMessageBoxOnError && VMError::is_error_reported()) { 4406 os::infinite_sleep(); 4407 } 4408 os::wait_for_keypress_at_exit(); 4409 4410 // run Java level shutdown hooks 4411 thread->invoke_shutdown_hooks(); 4412 4413 before_exit(thread); 4414 4415 thread->exit(true); 4416 4417 // Stop VM thread. 4418 { 4419 // 4945125 The vm thread comes to a safepoint during exit. 4420 // GC vm_operations can get caught at the safepoint, and the 4421 // heap is unparseable if they are caught. Grab the Heap_lock 4422 // to prevent this. The GC vm_operations will not be able to 4423 // queue until after the vm thread is dead. After this point, 4424 // we'll never emerge out of the safepoint before the VM exits. 4425 4426 MutexLocker ml(Heap_lock, Mutex::_no_safepoint_check_flag); 4427 4428 VMThread::wait_for_vm_thread_exit(); 4429 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4430 VMThread::destroy(); 4431 } 4432 4433 // Now, all Java threads are gone except daemon threads. Daemon threads 4434 // running Java code or in VM are stopped by the Safepoint. However, 4435 // daemon threads executing native code are still running. But they 4436 // will be stopped at native=>Java/VM barriers. Note that we can't 4437 // simply kill or suspend them, as it is inherently deadlock-prone. 4438 4439 VM_Exit::set_vm_exited(); 4440 4441 // Clean up ideal graph printers after the VMThread has started 4442 // the final safepoint which will block all the Compiler threads. 4443 // Note that this Thread has already logically exited so the 4444 // clean_up() function's use of a JavaThreadIteratorWithHandle 4445 // would be a problem except set_vm_exited() has remembered the 4446 // shutdown thread which is granted a policy exception. 4447 #if defined(COMPILER2) && !defined(PRODUCT) 4448 IdealGraphPrinter::clean_up(); 4449 #endif 4450 4451 notify_vm_shutdown(); 4452 4453 // exit_globals() will delete tty 4454 exit_globals(); 4455 4456 // We are after VM_Exit::set_vm_exited() so we can't call 4457 // thread->smr_delete() or we will block on the Threads_lock. 4458 // Deleting the shutdown thread here is safe because another 4459 // JavaThread cannot have an active ThreadsListHandle for 4460 // this JavaThread. 4461 delete thread; 4462 4463 #if INCLUDE_JVMCI 4464 if (JVMCICounterSize > 0) { 4465 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters); 4466 } 4467 #endif 4468 4469 LogConfiguration::finalize(); 4470 4471 return true; 4472 } 4473 4474 4475 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4476 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4477 return is_supported_jni_version(version); 4478 } 4479 4480 4481 jboolean Threads::is_supported_jni_version(jint version) { 4482 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4483 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4484 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4485 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4486 if (version == JNI_VERSION_9) return JNI_TRUE; 4487 if (version == JNI_VERSION_10) return JNI_TRUE; 4488 return JNI_FALSE; 4489 } 4490 4491 4492 void Threads::add(JavaThread* p, bool force_daemon) { 4493 // The threads lock must be owned at this point 4494 assert(Threads_lock->owned_by_self(), "must have threads lock"); 4495 4496 BarrierSet::barrier_set()->on_thread_attach(p); 4497 4498 // Once a JavaThread is added to the Threads list, smr_delete() has 4499 // to be used to delete it. Otherwise we can just delete it directly. 4500 p->set_on_thread_list(); 4501 4502 _number_of_threads++; 4503 oop threadObj = p->threadObj(); 4504 bool daemon = true; 4505 // Bootstrapping problem: threadObj can be null for initial 4506 // JavaThread (or for threads attached via JNI) 4507 if ((!force_daemon) && !is_daemon((threadObj))) { 4508 _number_of_non_daemon_threads++; 4509 daemon = false; 4510 } 4511 4512 ThreadService::add_thread(p, daemon); 4513 4514 // Maintain fast thread list 4515 ThreadsSMRSupport::add_thread(p); 4516 4517 // Possible GC point. 4518 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p)); 4519 } 4520 4521 void Threads::remove(JavaThread* p, bool is_daemon) { 4522 4523 // Reclaim the ObjectMonitors from the omInUseList and omFreeList of the moribund thread. 4524 ObjectSynchronizer::omFlush(p); 4525 4526 // Extra scope needed for Thread_lock, so we can check 4527 // that we do not remove thread without safepoint code notice 4528 { MonitorLocker ml(Threads_lock); 4529 4530 assert(ThreadsSMRSupport::get_java_thread_list()->includes(p), "p must be present"); 4531 4532 // Maintain fast thread list 4533 ThreadsSMRSupport::remove_thread(p); 4534 4535 _number_of_threads--; 4536 if (!is_daemon) { 4537 _number_of_non_daemon_threads--; 4538 4539 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4540 // on destroy_vm will wake up. 4541 if (number_of_non_daemon_threads() == 1) { 4542 ml.notify_all(); 4543 } 4544 } 4545 ThreadService::remove_thread(p, is_daemon); 4546 4547 // Make sure that safepoint code disregard this thread. This is needed since 4548 // the thread might mess around with locks after this point. This can cause it 4549 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4550 // of this thread since it is removed from the queue. 4551 p->set_terminated_value(); 4552 } // unlock Threads_lock 4553 4554 // Since Events::log uses a lock, we grab it outside the Threads_lock 4555 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p)); 4556 } 4557 4558 // Operations on the Threads list for GC. These are not explicitly locked, 4559 // but the garbage collector must provide a safe context for them to run. 4560 // In particular, these things should never be called when the Threads_lock 4561 // is held by some other thread. (Note: the Safepoint abstraction also 4562 // uses the Threads_lock to guarantee this property. It also makes sure that 4563 // all threads gets blocked when exiting or starting). 4564 4565 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) { 4566 ALL_JAVA_THREADS(p) { 4567 p->oops_do(f, cf); 4568 } 4569 VMThread::vm_thread()->oops_do(f, cf); 4570 } 4571 4572 void Threads::change_thread_claim_token() { 4573 if (++_thread_claim_token == 0) { 4574 // On overflow of the token counter, there is a risk of future 4575 // collisions between a new global token value and a stale token 4576 // for a thread, because not all iterations visit all threads. 4577 // (Though it's pretty much a theoretical concern for non-trivial 4578 // token counter sizes.) To deal with the possibility, reset all 4579 // the thread tokens to zero on global token overflow. 4580 struct ResetClaims : public ThreadClosure { 4581 virtual void do_thread(Thread* t) { 4582 t->claim_threads_do(false, 0); 4583 } 4584 } reset_claims; 4585 Threads::threads_do(&reset_claims); 4586 // On overflow, update the global token to non-zero, to 4587 // avoid the special "never claimed" initial thread value. 4588 _thread_claim_token = 1; 4589 } 4590 } 4591 4592 #ifdef ASSERT 4593 void assert_thread_claimed(const char* kind, Thread* t, uintx expected) { 4594 const uintx token = t->threads_do_token(); 4595 assert(token == expected, 4596 "%s " PTR_FORMAT " has incorrect value " UINTX_FORMAT " != " 4597 UINTX_FORMAT, kind, p2i(t), token, expected); 4598 } 4599 4600 void Threads::assert_all_threads_claimed() { 4601 ALL_JAVA_THREADS(p) { 4602 assert_thread_claimed("Thread", p, _thread_claim_token); 4603 } 4604 assert_thread_claimed("VMThread", VMThread::vm_thread(), _thread_claim_token); 4605 } 4606 #endif // ASSERT 4607 4608 class ParallelOopsDoThreadClosure : public ThreadClosure { 4609 private: 4610 OopClosure* _f; 4611 CodeBlobClosure* _cf; 4612 public: 4613 ParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf) : _f(f), _cf(cf) {} 4614 void do_thread(Thread* t) { 4615 t->oops_do(_f, _cf); 4616 } 4617 }; 4618 4619 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) { 4620 ParallelOopsDoThreadClosure tc(f, cf); 4621 possibly_parallel_threads_do(is_par, &tc); 4622 } 4623 4624 void Threads::nmethods_do(CodeBlobClosure* cf) { 4625 ALL_JAVA_THREADS(p) { 4626 // This is used by the code cache sweeper to mark nmethods that are active 4627 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid 4628 // marking CodeCacheSweeperThread::_scanned_compiled_method as active. 4629 if(!p->is_Code_cache_sweeper_thread()) { 4630 p->nmethods_do(cf); 4631 } 4632 } 4633 } 4634 4635 void Threads::metadata_do(MetadataClosure* f) { 4636 ALL_JAVA_THREADS(p) { 4637 p->metadata_do(f); 4638 } 4639 } 4640 4641 class ThreadHandlesClosure : public ThreadClosure { 4642 void (*_f)(Metadata*); 4643 public: 4644 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4645 virtual void do_thread(Thread* thread) { 4646 thread->metadata_handles_do(_f); 4647 } 4648 }; 4649 4650 void Threads::metadata_handles_do(void f(Metadata*)) { 4651 // Only walk the Handles in Thread. 4652 ThreadHandlesClosure handles_closure(f); 4653 threads_do(&handles_closure); 4654 } 4655 4656 void Threads::deoptimized_wrt_marked_nmethods() { 4657 ALL_JAVA_THREADS(p) { 4658 p->deoptimized_wrt_marked_nmethods(); 4659 } 4660 } 4661 4662 4663 // Get count Java threads that are waiting to enter the specified monitor. 4664 GrowableArray<JavaThread*>* Threads::get_pending_threads(ThreadsList * t_list, 4665 int count, 4666 address monitor) { 4667 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4668 4669 int i = 0; 4670 DO_JAVA_THREADS(t_list, p) { 4671 if (!p->can_call_java()) continue; 4672 4673 address pending = (address)p->current_pending_monitor(); 4674 if (pending == monitor) { // found a match 4675 if (i < count) result->append(p); // save the first count matches 4676 i++; 4677 } 4678 } 4679 4680 return result; 4681 } 4682 4683 4684 JavaThread *Threads::owning_thread_from_monitor_owner(ThreadsList * t_list, 4685 address owner) { 4686 // NULL owner means not locked so we can skip the search 4687 if (owner == NULL) return NULL; 4688 4689 DO_JAVA_THREADS(t_list, p) { 4690 // first, see if owner is the address of a Java thread 4691 if (owner == (address)p) return p; 4692 } 4693 4694 // Cannot assert on lack of success here since this function may be 4695 // used by code that is trying to report useful problem information 4696 // like deadlock detection. 4697 if (UseHeavyMonitors) return NULL; 4698 4699 // If we didn't find a matching Java thread and we didn't force use of 4700 // heavyweight monitors, then the owner is the stack address of the 4701 // Lock Word in the owning Java thread's stack. 4702 // 4703 JavaThread* the_owner = NULL; 4704 DO_JAVA_THREADS(t_list, q) { 4705 if (q->is_lock_owned(owner)) { 4706 the_owner = q; 4707 break; 4708 } 4709 } 4710 4711 // cannot assert on lack of success here; see above comment 4712 return the_owner; 4713 } 4714 4715 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4716 void Threads::print_on(outputStream* st, bool print_stacks, 4717 bool internal_format, bool print_concurrent_locks, 4718 bool print_extended_info) { 4719 char buf[32]; 4720 st->print_raw_cr(os::local_time_string(buf, sizeof(buf))); 4721 4722 st->print_cr("Full thread dump %s (%s %s):", 4723 VM_Version::vm_name(), 4724 VM_Version::vm_release(), 4725 VM_Version::vm_info_string()); 4726 st->cr(); 4727 4728 #if INCLUDE_SERVICES 4729 // Dump concurrent locks 4730 ConcurrentLocksDump concurrent_locks; 4731 if (print_concurrent_locks) { 4732 concurrent_locks.dump_at_safepoint(); 4733 } 4734 #endif // INCLUDE_SERVICES 4735 4736 ThreadsSMRSupport::print_info_on(st); 4737 st->cr(); 4738 4739 ALL_JAVA_THREADS(p) { 4740 ResourceMark rm; 4741 p->print_on(st, print_extended_info); 4742 if (print_stacks) { 4743 if (internal_format) { 4744 p->trace_stack(); 4745 } else { 4746 p->print_stack_on(st); 4747 } 4748 } 4749 st->cr(); 4750 #if INCLUDE_SERVICES 4751 if (print_concurrent_locks) { 4752 concurrent_locks.print_locks_on(p, st); 4753 } 4754 #endif // INCLUDE_SERVICES 4755 } 4756 4757 VMThread::vm_thread()->print_on(st); 4758 st->cr(); 4759 Universe::heap()->print_gc_threads_on(st); 4760 WatcherThread* wt = WatcherThread::watcher_thread(); 4761 if (wt != NULL) { 4762 wt->print_on(st); 4763 st->cr(); 4764 } 4765 4766 st->flush(); 4767 } 4768 4769 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf, 4770 int buflen, bool* found_current) { 4771 if (this_thread != NULL) { 4772 bool is_current = (current == this_thread); 4773 *found_current = *found_current || is_current; 4774 st->print("%s", is_current ? "=>" : " "); 4775 4776 st->print(PTR_FORMAT, p2i(this_thread)); 4777 st->print(" "); 4778 this_thread->print_on_error(st, buf, buflen); 4779 st->cr(); 4780 } 4781 } 4782 4783 class PrintOnErrorClosure : public ThreadClosure { 4784 outputStream* _st; 4785 Thread* _current; 4786 char* _buf; 4787 int _buflen; 4788 bool* _found_current; 4789 public: 4790 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf, 4791 int buflen, bool* found_current) : 4792 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {} 4793 4794 virtual void do_thread(Thread* thread) { 4795 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current); 4796 } 4797 }; 4798 4799 // Threads::print_on_error() is called by fatal error handler. It's possible 4800 // that VM is not at safepoint and/or current thread is inside signal handler. 4801 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4802 // memory (even in resource area), it might deadlock the error handler. 4803 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4804 int buflen) { 4805 ThreadsSMRSupport::print_info_on(st); 4806 st->cr(); 4807 4808 bool found_current = false; 4809 st->print_cr("Java Threads: ( => current thread )"); 4810 ALL_JAVA_THREADS(thread) { 4811 print_on_error(thread, st, current, buf, buflen, &found_current); 4812 } 4813 st->cr(); 4814 4815 st->print_cr("Other Threads:"); 4816 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current); 4817 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current); 4818 4819 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current); 4820 Universe::heap()->gc_threads_do(&print_closure); 4821 4822 if (!found_current) { 4823 st->cr(); 4824 st->print("=>" PTR_FORMAT " (exited) ", p2i(current)); 4825 current->print_on_error(st, buf, buflen); 4826 st->cr(); 4827 } 4828 st->cr(); 4829 4830 st->print_cr("Threads with active compile tasks:"); 4831 print_threads_compiling(st, buf, buflen); 4832 } 4833 4834 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form) { 4835 ALL_JAVA_THREADS(thread) { 4836 if (thread->is_Compiler_thread()) { 4837 CompilerThread* ct = (CompilerThread*) thread; 4838 4839 // Keep task in local variable for NULL check. 4840 // ct->_task might be set to NULL by concurring compiler thread 4841 // because it completed the compilation. The task is never freed, 4842 // though, just returned to a free list. 4843 CompileTask* task = ct->task(); 4844 if (task != NULL) { 4845 thread->print_name_on_error(st, buf, buflen); 4846 st->print(" "); 4847 task->print(st, NULL, short_form, true); 4848 } 4849 } 4850 } 4851 } 4852 4853 4854 // Internal SpinLock and Mutex 4855 // Based on ParkEvent 4856 4857 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4858 // 4859 // We employ SpinLocks _only for low-contention, fixed-length 4860 // short-duration critical sections where we're concerned 4861 // about native mutex_t or HotSpot Mutex:: latency. 4862 // The mux construct provides a spin-then-block mutual exclusion 4863 // mechanism. 4864 // 4865 // Testing has shown that contention on the ListLock guarding gFreeList 4866 // is common. If we implement ListLock as a simple SpinLock it's common 4867 // for the JVM to devolve to yielding with little progress. This is true 4868 // despite the fact that the critical sections protected by ListLock are 4869 // extremely short. 4870 // 4871 // TODO-FIXME: ListLock should be of type SpinLock. 4872 // We should make this a 1st-class type, integrated into the lock 4873 // hierarchy as leaf-locks. Critically, the SpinLock structure 4874 // should have sufficient padding to avoid false-sharing and excessive 4875 // cache-coherency traffic. 4876 4877 4878 typedef volatile int SpinLockT; 4879 4880 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4881 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4882 return; // normal fast-path return 4883 } 4884 4885 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4886 int ctr = 0; 4887 int Yields = 0; 4888 for (;;) { 4889 while (*adr != 0) { 4890 ++ctr; 4891 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4892 if (Yields > 5) { 4893 os::naked_short_sleep(1); 4894 } else { 4895 os::naked_yield(); 4896 ++Yields; 4897 } 4898 } else { 4899 SpinPause(); 4900 } 4901 } 4902 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4903 } 4904 } 4905 4906 void Thread::SpinRelease(volatile int * adr) { 4907 assert(*adr != 0, "invariant"); 4908 OrderAccess::fence(); // guarantee at least release consistency. 4909 // Roach-motel semantics. 4910 // It's safe if subsequent LDs and STs float "up" into the critical section, 4911 // but prior LDs and STs within the critical section can't be allowed 4912 // to reorder or float past the ST that releases the lock. 4913 // Loads and stores in the critical section - which appear in program 4914 // order before the store that releases the lock - must also appear 4915 // before the store that releases the lock in memory visibility order. 4916 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4917 // the ST of 0 into the lock-word which releases the lock, so fence 4918 // more than covers this on all platforms. 4919 *adr = 0; 4920 } 4921 4922 // muxAcquire and muxRelease: 4923 // 4924 // * muxAcquire and muxRelease support a single-word lock-word construct. 4925 // The LSB of the word is set IFF the lock is held. 4926 // The remainder of the word points to the head of a singly-linked list 4927 // of threads blocked on the lock. 4928 // 4929 // * The current implementation of muxAcquire-muxRelease uses its own 4930 // dedicated Thread._MuxEvent instance. If we're interested in 4931 // minimizing the peak number of extant ParkEvent instances then 4932 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4933 // as certain invariants were satisfied. Specifically, care would need 4934 // to be taken with regards to consuming unpark() "permits". 4935 // A safe rule of thumb is that a thread would never call muxAcquire() 4936 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4937 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4938 // consume an unpark() permit intended for monitorenter, for instance. 4939 // One way around this would be to widen the restricted-range semaphore 4940 // implemented in park(). Another alternative would be to provide 4941 // multiple instances of the PlatformEvent() for each thread. One 4942 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4943 // 4944 // * Usage: 4945 // -- Only as leaf locks 4946 // -- for short-term locking only as muxAcquire does not perform 4947 // thread state transitions. 4948 // 4949 // Alternatives: 4950 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4951 // but with parking or spin-then-park instead of pure spinning. 4952 // * Use Taura-Oyama-Yonenzawa locks. 4953 // * It's possible to construct a 1-0 lock if we encode the lockword as 4954 // (List,LockByte). Acquire will CAS the full lockword while Release 4955 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4956 // acquiring threads use timers (ParkTimed) to detect and recover from 4957 // the stranding window. Thread/Node structures must be aligned on 256-byte 4958 // boundaries by using placement-new. 4959 // * Augment MCS with advisory back-link fields maintained with CAS(). 4960 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4961 // The validity of the backlinks must be ratified before we trust the value. 4962 // If the backlinks are invalid the exiting thread must back-track through the 4963 // the forward links, which are always trustworthy. 4964 // * Add a successor indication. The LockWord is currently encoded as 4965 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4966 // to provide the usual futile-wakeup optimization. 4967 // See RTStt for details. 4968 // 4969 4970 4971 const intptr_t LOCKBIT = 1; 4972 4973 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4974 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0); 4975 if (w == 0) return; 4976 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 4977 return; 4978 } 4979 4980 ParkEvent * const Self = Thread::current()->_MuxEvent; 4981 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4982 for (;;) { 4983 int its = (os::is_MP() ? 100 : 0) + 1; 4984 4985 // Optional spin phase: spin-then-park strategy 4986 while (--its >= 0) { 4987 w = *Lock; 4988 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 4989 return; 4990 } 4991 } 4992 4993 Self->reset(); 4994 Self->OnList = intptr_t(Lock); 4995 // The following fence() isn't _strictly necessary as the subsequent 4996 // CAS() both serializes execution and ratifies the fetched *Lock value. 4997 OrderAccess::fence(); 4998 for (;;) { 4999 w = *Lock; 5000 if ((w & LOCKBIT) == 0) { 5001 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 5002 Self->OnList = 0; // hygiene - allows stronger asserts 5003 return; 5004 } 5005 continue; // Interference -- *Lock changed -- Just retry 5006 } 5007 assert(w & LOCKBIT, "invariant"); 5008 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 5009 if (Atomic::cmpxchg(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 5010 } 5011 5012 while (Self->OnList != 0) { 5013 Self->park(); 5014 } 5015 } 5016 } 5017 5018 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 5019 intptr_t w = Atomic::cmpxchg(LOCKBIT, Lock, (intptr_t)0); 5020 if (w == 0) return; 5021 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 5022 return; 5023 } 5024 5025 ParkEvent * ReleaseAfter = NULL; 5026 if (ev == NULL) { 5027 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 5028 } 5029 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 5030 for (;;) { 5031 guarantee(ev->OnList == 0, "invariant"); 5032 int its = (os::is_MP() ? 100 : 0) + 1; 5033 5034 // Optional spin phase: spin-then-park strategy 5035 while (--its >= 0) { 5036 w = *Lock; 5037 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 5038 if (ReleaseAfter != NULL) { 5039 ParkEvent::Release(ReleaseAfter); 5040 } 5041 return; 5042 } 5043 } 5044 5045 ev->reset(); 5046 ev->OnList = intptr_t(Lock); 5047 // The following fence() isn't _strictly necessary as the subsequent 5048 // CAS() both serializes execution and ratifies the fetched *Lock value. 5049 OrderAccess::fence(); 5050 for (;;) { 5051 w = *Lock; 5052 if ((w & LOCKBIT) == 0) { 5053 if (Atomic::cmpxchg(w|LOCKBIT, Lock, w) == w) { 5054 ev->OnList = 0; 5055 // We call ::Release while holding the outer lock, thus 5056 // artificially lengthening the critical section. 5057 // Consider deferring the ::Release() until the subsequent unlock(), 5058 // after we've dropped the outer lock. 5059 if (ReleaseAfter != NULL) { 5060 ParkEvent::Release(ReleaseAfter); 5061 } 5062 return; 5063 } 5064 continue; // Interference -- *Lock changed -- Just retry 5065 } 5066 assert(w & LOCKBIT, "invariant"); 5067 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 5068 if (Atomic::cmpxchg(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 5069 } 5070 5071 while (ev->OnList != 0) { 5072 ev->park(); 5073 } 5074 } 5075 } 5076 5077 // Release() must extract a successor from the list and then wake that thread. 5078 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 5079 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 5080 // Release() would : 5081 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 5082 // (B) Extract a successor from the private list "in-hand" 5083 // (C) attempt to CAS() the residual back into *Lock over null. 5084 // If there were any newly arrived threads and the CAS() would fail. 5085 // In that case Release() would detach the RATs, re-merge the list in-hand 5086 // with the RATs and repeat as needed. Alternately, Release() might 5087 // detach and extract a successor, but then pass the residual list to the wakee. 5088 // The wakee would be responsible for reattaching and remerging before it 5089 // competed for the lock. 5090 // 5091 // Both "pop" and DMR are immune from ABA corruption -- there can be 5092 // multiple concurrent pushers, but only one popper or detacher. 5093 // This implementation pops from the head of the list. This is unfair, 5094 // but tends to provide excellent throughput as hot threads remain hot. 5095 // (We wake recently run threads first). 5096 // 5097 // All paths through muxRelease() will execute a CAS. 5098 // Release consistency -- We depend on the CAS in muxRelease() to provide full 5099 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 5100 // executed within the critical section are complete and globally visible before the 5101 // store (CAS) to the lock-word that releases the lock becomes globally visible. 5102 void Thread::muxRelease(volatile intptr_t * Lock) { 5103 for (;;) { 5104 const intptr_t w = Atomic::cmpxchg((intptr_t)0, Lock, LOCKBIT); 5105 assert(w & LOCKBIT, "invariant"); 5106 if (w == LOCKBIT) return; 5107 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 5108 assert(List != NULL, "invariant"); 5109 assert(List->OnList == intptr_t(Lock), "invariant"); 5110 ParkEvent * const nxt = List->ListNext; 5111 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 5112 5113 // The following CAS() releases the lock and pops the head element. 5114 // The CAS() also ratifies the previously fetched lock-word value. 5115 if (Atomic::cmpxchg(intptr_t(nxt), Lock, w) != w) { 5116 continue; 5117 } 5118 List->OnList = 0; 5119 OrderAccess::fence(); 5120 List->unpark(); 5121 return; 5122 } 5123 } 5124 5125 5126 void Threads::verify() { 5127 ALL_JAVA_THREADS(p) { 5128 p->verify(); 5129 } 5130 VMThread* thread = VMThread::vm_thread(); 5131 if (thread != NULL) thread->verify(); 5132 }