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