1 /* 2 * Copyright (c) 1997, 2017, 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 "classfile/classLoader.hpp" 27 #include "classfile/javaClasses.hpp" 28 #include "classfile/moduleEntry.hpp" 29 #include "classfile/systemDictionary.hpp" 30 #include "classfile/vmSymbols.hpp" 31 #include "code/codeCache.hpp" 32 #include "code/scopeDesc.hpp" 33 #include "compiler/compileBroker.hpp" 34 #include "compiler/compileTask.hpp" 35 #include "gc/shared/gcId.hpp" 36 #include "gc/shared/gcLocker.inline.hpp" 37 #include "gc/shared/workgroup.hpp" 38 #include "interpreter/interpreter.hpp" 39 #include "interpreter/linkResolver.hpp" 40 #include "interpreter/oopMapCache.hpp" 41 #include "jvmtifiles/jvmtiEnv.hpp" 42 #include "logging/log.hpp" 43 #include "logging/logConfiguration.hpp" 44 #include "memory/metaspaceShared.hpp" 45 #include "memory/oopFactory.hpp" 46 #include "memory/resourceArea.hpp" 47 #include "memory/universe.inline.hpp" 48 #include "oops/instanceKlass.hpp" 49 #include "oops/objArrayOop.hpp" 50 #include "oops/oop.inline.hpp" 51 #include "oops/symbol.hpp" 52 #include "oops/typeArrayOop.inline.hpp" 53 #include "oops/verifyOopClosure.hpp" 54 #include "prims/jvm_misc.hpp" 55 #include "prims/jvmtiExport.hpp" 56 #include "prims/jvmtiThreadState.hpp" 57 #include "prims/privilegedStack.hpp" 58 #include "runtime/arguments.hpp" 59 #include "runtime/atomic.hpp" 60 #include "runtime/biasedLocking.hpp" 61 #include "runtime/commandLineFlagConstraintList.hpp" 62 #include "runtime/commandLineFlagWriteableList.hpp" 63 #include "runtime/commandLineFlagRangeList.hpp" 64 #include "runtime/deoptimization.hpp" 65 #include "runtime/fprofiler.hpp" 66 #include "runtime/frame.inline.hpp" 67 #include "runtime/globals.hpp" 68 #include "runtime/init.hpp" 69 #include "runtime/interfaceSupport.hpp" 70 #include "runtime/java.hpp" 71 #include "runtime/javaCalls.hpp" 72 #include "runtime/jniPeriodicChecker.hpp" 73 #include "runtime/timerTrace.hpp" 74 #include "runtime/memprofiler.hpp" 75 #include "runtime/mutexLocker.hpp" 76 #include "runtime/objectMonitor.hpp" 77 #include "runtime/orderAccess.inline.hpp" 78 #include "runtime/osThread.hpp" 79 #include "runtime/safepoint.hpp" 80 #include "runtime/sharedRuntime.hpp" 81 #include "runtime/statSampler.hpp" 82 #include "runtime/stubRoutines.hpp" 83 #include "runtime/sweeper.hpp" 84 #include "runtime/task.hpp" 85 #include "runtime/thread.inline.hpp" 86 #include "runtime/threadCritical.hpp" 87 #include "runtime/vframe.hpp" 88 #include "runtime/vframeArray.hpp" 89 #include "runtime/vframe_hp.hpp" 90 #include "runtime/vmThread.hpp" 91 #include "runtime/vm_operations.hpp" 92 #include "runtime/vm_version.hpp" 93 #include "services/attachListener.hpp" 94 #include "services/management.hpp" 95 #include "services/memTracker.hpp" 96 #include "services/threadService.hpp" 97 #include "trace/traceMacros.hpp" 98 #include "trace/tracing.hpp" 99 #include "utilities/defaultStream.hpp" 100 #include "utilities/dtrace.hpp" 101 #include "utilities/events.hpp" 102 #include "utilities/macros.hpp" 103 #include "utilities/preserveException.hpp" 104 #if INCLUDE_ALL_GCS 105 #include "gc/cms/concurrentMarkSweepThread.hpp" 106 #include "gc/g1/concurrentMarkThread.inline.hpp" 107 #include "gc/parallel/pcTasks.hpp" 108 #endif // INCLUDE_ALL_GCS 109 #if INCLUDE_JVMCI 110 #include "jvmci/jvmciCompiler.hpp" 111 #include "jvmci/jvmciRuntime.hpp" 112 #endif 113 #ifdef COMPILER1 114 #include "c1/c1_Compiler.hpp" 115 #endif 116 #ifdef COMPILER2 117 #include "opto/c2compiler.hpp" 118 #include "opto/idealGraphPrinter.hpp" 119 #endif 120 #if INCLUDE_RTM_OPT 121 #include "runtime/rtmLocking.hpp" 122 #endif 123 124 // Initialization after module runtime initialization 125 void universe_post_module_init(); // must happen after call_initPhase2 126 127 #ifdef DTRACE_ENABLED 128 129 // Only bother with this argument setup if dtrace is available 130 131 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 132 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 133 134 #define DTRACE_THREAD_PROBE(probe, javathread) \ 135 { \ 136 ResourceMark rm(this); \ 137 int len = 0; \ 138 const char* name = (javathread)->get_thread_name(); \ 139 len = strlen(name); \ 140 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 141 (char *) name, len, \ 142 java_lang_Thread::thread_id((javathread)->threadObj()), \ 143 (uintptr_t) (javathread)->osthread()->thread_id(), \ 144 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 145 } 146 147 #else // ndef DTRACE_ENABLED 148 149 #define DTRACE_THREAD_PROBE(probe, javathread) 150 151 #endif // ndef DTRACE_ENABLED 152 153 #ifndef USE_LIBRARY_BASED_TLS_ONLY 154 // Current thread is maintained as a thread-local variable 155 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL; 156 #endif 157 // Class hierarchy 158 // - Thread 159 // - VMThread 160 // - WatcherThread 161 // - ConcurrentMarkSweepThread 162 // - JavaThread 163 // - CompilerThread 164 165 // ======= Thread ======== 166 // Support for forcing alignment of thread objects for biased locking 167 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 168 if (UseBiasedLocking) { 169 const int alignment = markOopDesc::biased_lock_alignment; 170 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 171 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 172 : AllocateHeap(aligned_size, flags, CURRENT_PC, 173 AllocFailStrategy::RETURN_NULL); 174 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 175 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 176 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 177 "JavaThread alignment code overflowed allocated storage"); 178 if (aligned_addr != real_malloc_addr) { 179 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 180 p2i(real_malloc_addr), 181 p2i(aligned_addr)); 182 } 183 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 184 return aligned_addr; 185 } else { 186 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 187 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 188 } 189 } 190 191 void Thread::operator delete(void* p) { 192 if (UseBiasedLocking) { 193 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 194 FreeHeap(real_malloc_addr); 195 } else { 196 FreeHeap(p); 197 } 198 } 199 200 201 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 202 // JavaThread 203 204 205 Thread::Thread() { 206 // stack and get_thread 207 set_stack_base(NULL); 208 set_stack_size(0); 209 set_self_raw_id(0); 210 set_lgrp_id(-1); 211 DEBUG_ONLY(clear_suspendible_thread();) 212 213 // allocated data structures 214 set_osthread(NULL); 215 set_resource_area(new (mtThread)ResourceArea()); 216 DEBUG_ONLY(_current_resource_mark = NULL;) 217 set_handle_area(new (mtThread) HandleArea(NULL)); 218 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 219 set_active_handles(NULL); 220 set_free_handle_block(NULL); 221 set_last_handle_mark(NULL); 222 223 // This initial value ==> never claimed. 224 _oops_do_parity = 0; 225 226 // the handle mark links itself to last_handle_mark 227 new HandleMark(this); 228 229 // plain initialization 230 debug_only(_owned_locks = NULL;) 231 debug_only(_allow_allocation_count = 0;) 232 NOT_PRODUCT(_allow_safepoint_count = 0;) 233 NOT_PRODUCT(_skip_gcalot = false;) 234 _jvmti_env_iteration_count = 0; 235 set_allocated_bytes(0); 236 _vm_operation_started_count = 0; 237 _vm_operation_completed_count = 0; 238 _current_pending_monitor = NULL; 239 _current_pending_monitor_is_from_java = true; 240 _current_waiting_monitor = NULL; 241 _num_nested_signal = 0; 242 omFreeList = NULL; 243 omFreeCount = 0; 244 omFreeProvision = 32; 245 omInUseList = NULL; 246 omInUseCount = 0; 247 248 #ifdef ASSERT 249 _visited_for_critical_count = false; 250 #endif 251 252 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, 253 Monitor::_safepoint_check_sometimes); 254 _suspend_flags = 0; 255 256 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 257 _hashStateX = os::random(); 258 _hashStateY = 842502087; 259 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 260 _hashStateW = 273326509; 261 262 _OnTrap = 0; 263 _schedctl = NULL; 264 _Stalled = 0; 265 _TypeTag = 0x2BAD; 266 267 // Many of the following fields are effectively final - immutable 268 // Note that nascent threads can't use the Native Monitor-Mutex 269 // construct until the _MutexEvent is initialized ... 270 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 271 // we might instead use a stack of ParkEvents that we could provision on-demand. 272 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 273 // and ::Release() 274 _ParkEvent = ParkEvent::Allocate(this); 275 _SleepEvent = ParkEvent::Allocate(this); 276 _MutexEvent = ParkEvent::Allocate(this); 277 _MuxEvent = ParkEvent::Allocate(this); 278 279 #ifdef CHECK_UNHANDLED_OOPS 280 if (CheckUnhandledOops) { 281 _unhandled_oops = new UnhandledOops(this); 282 } 283 #endif // CHECK_UNHANDLED_OOPS 284 #ifdef ASSERT 285 if (UseBiasedLocking) { 286 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 287 assert(this == _real_malloc_address || 288 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 289 "bug in forced alignment of thread objects"); 290 } 291 #endif // ASSERT 292 } 293 294 void Thread::initialize_thread_current() { 295 #ifndef USE_LIBRARY_BASED_TLS_ONLY 296 assert(_thr_current == NULL, "Thread::current already initialized"); 297 _thr_current = this; 298 #endif 299 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized"); 300 ThreadLocalStorage::set_thread(this); 301 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 302 } 303 304 void Thread::clear_thread_current() { 305 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 306 #ifndef USE_LIBRARY_BASED_TLS_ONLY 307 _thr_current = NULL; 308 #endif 309 ThreadLocalStorage::set_thread(NULL); 310 } 311 312 void Thread::record_stack_base_and_size() { 313 set_stack_base(os::current_stack_base()); 314 set_stack_size(os::current_stack_size()); 315 // CR 7190089: on Solaris, primordial thread's stack is adjusted 316 // in initialize_thread(). Without the adjustment, stack size is 317 // incorrect if stack is set to unlimited (ulimit -s unlimited). 318 // So far, only Solaris has real implementation of initialize_thread(). 319 // 320 // set up any platform-specific state. 321 os::initialize_thread(this); 322 323 // Set stack limits after thread is initialized. 324 if (is_Java_thread()) { 325 ((JavaThread*) this)->set_stack_overflow_limit(); 326 ((JavaThread*) this)->set_reserved_stack_activation(stack_base()); 327 } 328 #if INCLUDE_NMT 329 // record thread's native stack, stack grows downward 330 MemTracker::record_thread_stack(stack_end(), stack_size()); 331 #endif // INCLUDE_NMT 332 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: " 333 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).", 334 os::current_thread_id(), p2i(stack_base() - stack_size()), 335 p2i(stack_base()), stack_size()/1024); 336 } 337 338 339 Thread::~Thread() { 340 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 341 ObjectSynchronizer::omFlush(this); 342 343 EVENT_THREAD_DESTRUCT(this); 344 345 // stack_base can be NULL if the thread is never started or exited before 346 // record_stack_base_and_size called. Although, we would like to ensure 347 // that all started threads do call record_stack_base_and_size(), there is 348 // not proper way to enforce that. 349 #if INCLUDE_NMT 350 if (_stack_base != NULL) { 351 MemTracker::release_thread_stack(stack_end(), stack_size()); 352 #ifdef ASSERT 353 set_stack_base(NULL); 354 #endif 355 } 356 #endif // INCLUDE_NMT 357 358 // deallocate data structures 359 delete resource_area(); 360 // since the handle marks are using the handle area, we have to deallocated the root 361 // handle mark before deallocating the thread's handle area, 362 assert(last_handle_mark() != NULL, "check we have an element"); 363 delete last_handle_mark(); 364 assert(last_handle_mark() == NULL, "check we have reached the end"); 365 366 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 367 // We NULL out the fields for good hygiene. 368 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 369 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 370 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 371 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 372 373 delete handle_area(); 374 delete metadata_handles(); 375 376 // SR_handler uses this as a termination indicator - 377 // needs to happen before os::free_thread() 378 delete _SR_lock; 379 _SR_lock = NULL; 380 381 // osthread() can be NULL, if creation of thread failed. 382 if (osthread() != NULL) os::free_thread(osthread()); 383 384 // clear Thread::current if thread is deleting itself. 385 // Needed to ensure JNI correctly detects non-attached threads. 386 if (this == Thread::current()) { 387 clear_thread_current(); 388 } 389 390 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 391 } 392 393 // NOTE: dummy function for assertion purpose. 394 void Thread::run() { 395 ShouldNotReachHere(); 396 } 397 398 #ifdef ASSERT 399 // Private method to check for dangling thread pointer 400 void check_for_dangling_thread_pointer(Thread *thread) { 401 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 402 "possibility of dangling Thread pointer"); 403 } 404 #endif 405 406 ThreadPriority Thread::get_priority(const Thread* const thread) { 407 ThreadPriority priority; 408 // Can return an error! 409 (void)os::get_priority(thread, priority); 410 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 411 return priority; 412 } 413 414 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 415 debug_only(check_for_dangling_thread_pointer(thread);) 416 // Can return an error! 417 (void)os::set_priority(thread, priority); 418 } 419 420 421 void Thread::start(Thread* thread) { 422 // Start is different from resume in that its safety is guaranteed by context or 423 // being called from a Java method synchronized on the Thread object. 424 if (!DisableStartThread) { 425 if (thread->is_Java_thread()) { 426 // Initialize the thread state to RUNNABLE before starting this thread. 427 // Can not set it after the thread started because we do not know the 428 // exact thread state at that time. It could be in MONITOR_WAIT or 429 // in SLEEPING or some other state. 430 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 431 java_lang_Thread::RUNNABLE); 432 } 433 os::start_thread(thread); 434 } 435 } 436 437 // Enqueue a VM_Operation to do the job for us - sometime later 438 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 439 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 440 VMThread::execute(vm_stop); 441 } 442 443 444 // Check if an external suspend request has completed (or has been 445 // cancelled). Returns true if the thread is externally suspended and 446 // false otherwise. 447 // 448 // The bits parameter returns information about the code path through 449 // the routine. Useful for debugging: 450 // 451 // set in is_ext_suspend_completed(): 452 // 0x00000001 - routine was entered 453 // 0x00000010 - routine return false at end 454 // 0x00000100 - thread exited (return false) 455 // 0x00000200 - suspend request cancelled (return false) 456 // 0x00000400 - thread suspended (return true) 457 // 0x00001000 - thread is in a suspend equivalent state (return true) 458 // 0x00002000 - thread is native and walkable (return true) 459 // 0x00004000 - thread is native_trans and walkable (needed retry) 460 // 461 // set in wait_for_ext_suspend_completion(): 462 // 0x00010000 - routine was entered 463 // 0x00020000 - suspend request cancelled before loop (return false) 464 // 0x00040000 - thread suspended before loop (return true) 465 // 0x00080000 - suspend request cancelled in loop (return false) 466 // 0x00100000 - thread suspended in loop (return true) 467 // 0x00200000 - suspend not completed during retry loop (return false) 468 469 // Helper class for tracing suspend wait debug bits. 470 // 471 // 0x00000100 indicates that the target thread exited before it could 472 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 473 // 0x00080000 each indicate a cancelled suspend request so they don't 474 // count as wait failures either. 475 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 476 477 class TraceSuspendDebugBits : public StackObj { 478 private: 479 JavaThread * jt; 480 bool is_wait; 481 bool called_by_wait; // meaningful when !is_wait 482 uint32_t * bits; 483 484 public: 485 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 486 uint32_t *_bits) { 487 jt = _jt; 488 is_wait = _is_wait; 489 called_by_wait = _called_by_wait; 490 bits = _bits; 491 } 492 493 ~TraceSuspendDebugBits() { 494 if (!is_wait) { 495 #if 1 496 // By default, don't trace bits for is_ext_suspend_completed() calls. 497 // That trace is very chatty. 498 return; 499 #else 500 if (!called_by_wait) { 501 // If tracing for is_ext_suspend_completed() is enabled, then only 502 // trace calls to it from wait_for_ext_suspend_completion() 503 return; 504 } 505 #endif 506 } 507 508 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 509 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 510 MutexLocker ml(Threads_lock); // needed for get_thread_name() 511 ResourceMark rm; 512 513 tty->print_cr( 514 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 515 jt->get_thread_name(), *bits); 516 517 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 518 } 519 } 520 } 521 }; 522 #undef DEBUG_FALSE_BITS 523 524 525 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 526 uint32_t *bits) { 527 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 528 529 bool did_trans_retry = false; // only do thread_in_native_trans retry once 530 bool do_trans_retry; // flag to force the retry 531 532 *bits |= 0x00000001; 533 534 do { 535 do_trans_retry = false; 536 537 if (is_exiting()) { 538 // Thread is in the process of exiting. This is always checked 539 // first to reduce the risk of dereferencing a freed JavaThread. 540 *bits |= 0x00000100; 541 return false; 542 } 543 544 if (!is_external_suspend()) { 545 // Suspend request is cancelled. This is always checked before 546 // is_ext_suspended() to reduce the risk of a rogue resume 547 // confusing the thread that made the suspend request. 548 *bits |= 0x00000200; 549 return false; 550 } 551 552 if (is_ext_suspended()) { 553 // thread is suspended 554 *bits |= 0x00000400; 555 return true; 556 } 557 558 // Now that we no longer do hard suspends of threads running 559 // native code, the target thread can be changing thread state 560 // while we are in this routine: 561 // 562 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 563 // 564 // We save a copy of the thread state as observed at this moment 565 // and make our decision about suspend completeness based on the 566 // copy. This closes the race where the thread state is seen as 567 // _thread_in_native_trans in the if-thread_blocked check, but is 568 // seen as _thread_blocked in if-thread_in_native_trans check. 569 JavaThreadState save_state = thread_state(); 570 571 if (save_state == _thread_blocked && is_suspend_equivalent()) { 572 // If the thread's state is _thread_blocked and this blocking 573 // condition is known to be equivalent to a suspend, then we can 574 // consider the thread to be externally suspended. This means that 575 // the code that sets _thread_blocked has been modified to do 576 // self-suspension if the blocking condition releases. We also 577 // used to check for CONDVAR_WAIT here, but that is now covered by 578 // the _thread_blocked with self-suspension check. 579 // 580 // Return true since we wouldn't be here unless there was still an 581 // external suspend request. 582 *bits |= 0x00001000; 583 return true; 584 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 585 // Threads running native code will self-suspend on native==>VM/Java 586 // transitions. If its stack is walkable (should always be the case 587 // unless this function is called before the actual java_suspend() 588 // call), then the wait is done. 589 *bits |= 0x00002000; 590 return true; 591 } else if (!called_by_wait && !did_trans_retry && 592 save_state == _thread_in_native_trans && 593 frame_anchor()->walkable()) { 594 // The thread is transitioning from thread_in_native to another 595 // thread state. check_safepoint_and_suspend_for_native_trans() 596 // will force the thread to self-suspend. If it hasn't gotten 597 // there yet we may have caught the thread in-between the native 598 // code check above and the self-suspend. Lucky us. If we were 599 // called by wait_for_ext_suspend_completion(), then it 600 // will be doing the retries so we don't have to. 601 // 602 // Since we use the saved thread state in the if-statement above, 603 // there is a chance that the thread has already transitioned to 604 // _thread_blocked by the time we get here. In that case, we will 605 // make a single unnecessary pass through the logic below. This 606 // doesn't hurt anything since we still do the trans retry. 607 608 *bits |= 0x00004000; 609 610 // Once the thread leaves thread_in_native_trans for another 611 // thread state, we break out of this retry loop. We shouldn't 612 // need this flag to prevent us from getting back here, but 613 // sometimes paranoia is good. 614 did_trans_retry = true; 615 616 // We wait for the thread to transition to a more usable state. 617 for (int i = 1; i <= SuspendRetryCount; i++) { 618 // We used to do an "os::yield_all(i)" call here with the intention 619 // that yielding would increase on each retry. However, the parameter 620 // is ignored on Linux which means the yield didn't scale up. Waiting 621 // on the SR_lock below provides a much more predictable scale up for 622 // the delay. It also provides a simple/direct point to check for any 623 // safepoint requests from the VMThread 624 625 // temporarily drops SR_lock while doing wait with safepoint check 626 // (if we're a JavaThread - the WatcherThread can also call this) 627 // and increase delay with each retry 628 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 629 630 // check the actual thread state instead of what we saved above 631 if (thread_state() != _thread_in_native_trans) { 632 // the thread has transitioned to another thread state so 633 // try all the checks (except this one) one more time. 634 do_trans_retry = true; 635 break; 636 } 637 } // end retry loop 638 639 640 } 641 } while (do_trans_retry); 642 643 *bits |= 0x00000010; 644 return false; 645 } 646 647 // Wait for an external suspend request to complete (or be cancelled). 648 // Returns true if the thread is externally suspended and false otherwise. 649 // 650 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 651 uint32_t *bits) { 652 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 653 false /* !called_by_wait */, bits); 654 655 // local flag copies to minimize SR_lock hold time 656 bool is_suspended; 657 bool pending; 658 uint32_t reset_bits; 659 660 // set a marker so is_ext_suspend_completed() knows we are the caller 661 *bits |= 0x00010000; 662 663 // We use reset_bits to reinitialize the bits value at the top of 664 // each retry loop. This allows the caller to make use of any 665 // unused bits for their own marking purposes. 666 reset_bits = *bits; 667 668 { 669 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 670 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 671 delay, bits); 672 pending = is_external_suspend(); 673 } 674 // must release SR_lock to allow suspension to complete 675 676 if (!pending) { 677 // A cancelled suspend request is the only false return from 678 // is_ext_suspend_completed() that keeps us from entering the 679 // retry loop. 680 *bits |= 0x00020000; 681 return false; 682 } 683 684 if (is_suspended) { 685 *bits |= 0x00040000; 686 return true; 687 } 688 689 for (int i = 1; i <= retries; i++) { 690 *bits = reset_bits; // reinit to only track last retry 691 692 // We used to do an "os::yield_all(i)" call here with the intention 693 // that yielding would increase on each retry. However, the parameter 694 // is ignored on Linux which means the yield didn't scale up. Waiting 695 // on the SR_lock below provides a much more predictable scale up for 696 // the delay. It also provides a simple/direct point to check for any 697 // safepoint requests from the VMThread 698 699 { 700 MutexLocker ml(SR_lock()); 701 // wait with safepoint check (if we're a JavaThread - the WatcherThread 702 // can also call this) and increase delay with each retry 703 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 704 705 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 706 delay, bits); 707 708 // It is possible for the external suspend request to be cancelled 709 // (by a resume) before the actual suspend operation is completed. 710 // Refresh our local copy to see if we still need to wait. 711 pending = is_external_suspend(); 712 } 713 714 if (!pending) { 715 // A cancelled suspend request is the only false return from 716 // is_ext_suspend_completed() that keeps us from staying in the 717 // retry loop. 718 *bits |= 0x00080000; 719 return false; 720 } 721 722 if (is_suspended) { 723 *bits |= 0x00100000; 724 return true; 725 } 726 } // end retry loop 727 728 // thread did not suspend after all our retries 729 *bits |= 0x00200000; 730 return false; 731 } 732 733 #ifndef PRODUCT 734 void JavaThread::record_jump(address target, address instr, const char* file, 735 int line) { 736 737 // This should not need to be atomic as the only way for simultaneous 738 // updates is via interrupts. Even then this should be rare or non-existent 739 // and we don't care that much anyway. 740 741 int index = _jmp_ring_index; 742 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 743 _jmp_ring[index]._target = (intptr_t) target; 744 _jmp_ring[index]._instruction = (intptr_t) instr; 745 _jmp_ring[index]._file = file; 746 _jmp_ring[index]._line = line; 747 } 748 #endif // PRODUCT 749 750 // Called by flat profiler 751 // Callers have already called wait_for_ext_suspend_completion 752 // The assertion for that is currently too complex to put here: 753 bool JavaThread::profile_last_Java_frame(frame* _fr) { 754 bool gotframe = false; 755 // self suspension saves needed state. 756 if (has_last_Java_frame() && _anchor.walkable()) { 757 *_fr = pd_last_frame(); 758 gotframe = true; 759 } 760 return gotframe; 761 } 762 763 void Thread::interrupt(Thread* thread) { 764 debug_only(check_for_dangling_thread_pointer(thread);) 765 os::interrupt(thread); 766 } 767 768 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 769 debug_only(check_for_dangling_thread_pointer(thread);) 770 // Note: If clear_interrupted==false, this simply fetches and 771 // returns the value of the field osthread()->interrupted(). 772 return os::is_interrupted(thread, clear_interrupted); 773 } 774 775 776 // GC Support 777 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 778 jint thread_parity = _oops_do_parity; 779 if (thread_parity != strong_roots_parity) { 780 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 781 if (res == thread_parity) { 782 return true; 783 } else { 784 guarantee(res == strong_roots_parity, "Or else what?"); 785 return false; 786 } 787 } 788 return false; 789 } 790 791 void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 792 active_handles()->oops_do(f); 793 // Do oop for ThreadShadow 794 f->do_oop((oop*)&_pending_exception); 795 handle_area()->oops_do(f); 796 } 797 798 void Thread::metadata_handles_do(void f(Metadata*)) { 799 // Only walk the Handles in Thread. 800 if (metadata_handles() != NULL) { 801 for (int i = 0; i< metadata_handles()->length(); i++) { 802 f(metadata_handles()->at(i)); 803 } 804 } 805 } 806 807 void Thread::print_on(outputStream* st) const { 808 // get_priority assumes osthread initialized 809 if (osthread() != NULL) { 810 int os_prio; 811 if (os::get_native_priority(this, &os_prio) == OS_OK) { 812 st->print("os_prio=%d ", os_prio); 813 } 814 st->print("tid=" INTPTR_FORMAT " ", p2i(this)); 815 ext().print_on(st); 816 osthread()->print_on(st); 817 } 818 debug_only(if (WizardMode) print_owned_locks_on(st);) 819 } 820 821 // Thread::print_on_error() is called by fatal error handler. Don't use 822 // any lock or allocate memory. 823 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 824 assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates"); 825 826 if (is_VM_thread()) { st->print("VMThread"); } 827 else if (is_GC_task_thread()) { st->print("GCTaskThread"); } 828 else if (is_Watcher_thread()) { st->print("WatcherThread"); } 829 else if (is_ConcurrentGC_thread()) { st->print("ConcurrentGCThread"); } 830 else { st->print("Thread"); } 831 832 if (is_Named_thread()) { 833 st->print(" \"%s\"", name()); 834 } 835 836 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 837 p2i(stack_end()), p2i(stack_base())); 838 839 if (osthread()) { 840 st->print(" [id=%d]", osthread()->thread_id()); 841 } 842 } 843 844 #ifdef ASSERT 845 void Thread::print_owned_locks_on(outputStream* st) const { 846 Monitor *cur = _owned_locks; 847 if (cur == NULL) { 848 st->print(" (no locks) "); 849 } else { 850 st->print_cr(" Locks owned:"); 851 while (cur) { 852 cur->print_on(st); 853 cur = cur->next(); 854 } 855 } 856 } 857 858 static int ref_use_count = 0; 859 860 bool Thread::owns_locks_but_compiled_lock() const { 861 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 862 if (cur != Compile_lock) return true; 863 } 864 return false; 865 } 866 867 868 #endif 869 870 #ifndef PRODUCT 871 872 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 873 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 874 // no threads which allow_vm_block's are held 875 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 876 // Check if current thread is allowed to block at a safepoint 877 if (!(_allow_safepoint_count == 0)) { 878 fatal("Possible safepoint reached by thread that does not allow it"); 879 } 880 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 881 fatal("LEAF method calling lock?"); 882 } 883 884 #ifdef ASSERT 885 if (potential_vm_operation && is_Java_thread() 886 && !Universe::is_bootstrapping()) { 887 // Make sure we do not hold any locks that the VM thread also uses. 888 // This could potentially lead to deadlocks 889 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 890 // Threads_lock is special, since the safepoint synchronization will not start before this is 891 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 892 // since it is used to transfer control between JavaThreads and the VMThread 893 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 894 if ((cur->allow_vm_block() && 895 cur != Threads_lock && 896 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 897 cur != VMOperationRequest_lock && 898 cur != VMOperationQueue_lock) || 899 cur->rank() == Mutex::special) { 900 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 901 } 902 } 903 } 904 905 if (GCALotAtAllSafepoints) { 906 // We could enter a safepoint here and thus have a gc 907 InterfaceSupport::check_gc_alot(); 908 } 909 #endif 910 } 911 #endif 912 913 bool Thread::is_in_stack(address adr) const { 914 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 915 address end = os::current_stack_pointer(); 916 // Allow non Java threads to call this without stack_base 917 if (_stack_base == NULL) return true; 918 if (stack_base() >= adr && adr >= end) return true; 919 920 return false; 921 } 922 923 bool Thread::is_in_usable_stack(address adr) const { 924 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0; 925 size_t usable_stack_size = _stack_size - stack_guard_size; 926 927 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 928 } 929 930 931 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 932 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 933 // used for compilation in the future. If that change is made, the need for these methods 934 // should be revisited, and they should be removed if possible. 935 936 bool Thread::is_lock_owned(address adr) const { 937 return on_local_stack(adr); 938 } 939 940 bool Thread::set_as_starting_thread() { 941 // NOTE: this must be called inside the main thread. 942 return os::create_main_thread((JavaThread*)this); 943 } 944 945 static void initialize_class(Symbol* class_name, TRAPS) { 946 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 947 InstanceKlass::cast(klass)->initialize(CHECK); 948 } 949 950 951 // Creates the initial ThreadGroup 952 static Handle create_initial_thread_group(TRAPS) { 953 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 954 InstanceKlass* ik = InstanceKlass::cast(k); 955 956 Handle system_instance = ik->allocate_instance_handle(CHECK_NH); 957 { 958 JavaValue result(T_VOID); 959 JavaCalls::call_special(&result, 960 system_instance, 961 ik, 962 vmSymbols::object_initializer_name(), 963 vmSymbols::void_method_signature(), 964 CHECK_NH); 965 } 966 Universe::set_system_thread_group(system_instance()); 967 968 Handle main_instance = ik->allocate_instance_handle(CHECK_NH); 969 { 970 JavaValue result(T_VOID); 971 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 972 JavaCalls::call_special(&result, 973 main_instance, 974 ik, 975 vmSymbols::object_initializer_name(), 976 vmSymbols::threadgroup_string_void_signature(), 977 system_instance, 978 string, 979 CHECK_NH); 980 } 981 return main_instance; 982 } 983 984 // Creates the initial Thread 985 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 986 TRAPS) { 987 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 988 InstanceKlass* ik = InstanceKlass::cast(k); 989 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL); 990 991 java_lang_Thread::set_thread(thread_oop(), thread); 992 java_lang_Thread::set_priority(thread_oop(), NormPriority); 993 thread->set_threadObj(thread_oop()); 994 995 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 996 997 JavaValue result(T_VOID); 998 JavaCalls::call_special(&result, thread_oop, 999 ik, 1000 vmSymbols::object_initializer_name(), 1001 vmSymbols::threadgroup_string_void_signature(), 1002 thread_group, 1003 string, 1004 CHECK_NULL); 1005 return thread_oop(); 1006 } 1007 1008 char java_runtime_name[128] = ""; 1009 char java_runtime_version[128] = ""; 1010 1011 // extract the JRE name from java.lang.VersionProps.java_runtime_name 1012 static const char* get_java_runtime_name(TRAPS) { 1013 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1014 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1015 fieldDescriptor fd; 1016 bool found = k != NULL && 1017 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1018 vmSymbols::string_signature(), &fd); 1019 if (found) { 1020 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1021 if (name_oop == NULL) { 1022 return NULL; 1023 } 1024 const char* name = java_lang_String::as_utf8_string(name_oop, 1025 java_runtime_name, 1026 sizeof(java_runtime_name)); 1027 return name; 1028 } else { 1029 return NULL; 1030 } 1031 } 1032 1033 // extract the JRE version from java.lang.VersionProps.java_runtime_version 1034 static const char* get_java_runtime_version(TRAPS) { 1035 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1036 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1037 fieldDescriptor fd; 1038 bool found = k != NULL && 1039 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1040 vmSymbols::string_signature(), &fd); 1041 if (found) { 1042 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1043 if (name_oop == NULL) { 1044 return NULL; 1045 } 1046 const char* name = java_lang_String::as_utf8_string(name_oop, 1047 java_runtime_version, 1048 sizeof(java_runtime_version)); 1049 return name; 1050 } else { 1051 return NULL; 1052 } 1053 } 1054 1055 // General purpose hook into Java code, run once when the VM is initialized. 1056 // The Java library method itself may be changed independently from the VM. 1057 static void call_postVMInitHook(TRAPS) { 1058 Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD); 1059 if (klass != NULL) { 1060 JavaValue result(T_VOID); 1061 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1062 vmSymbols::void_method_signature(), 1063 CHECK); 1064 } 1065 } 1066 1067 static void reset_vm_info_property(TRAPS) { 1068 // the vm info string 1069 ResourceMark rm(THREAD); 1070 const char *vm_info = VM_Version::vm_info_string(); 1071 1072 // java.lang.System class 1073 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1074 1075 // setProperty arguments 1076 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1077 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1078 1079 // return value 1080 JavaValue r(T_OBJECT); 1081 1082 // public static String setProperty(String key, String value); 1083 JavaCalls::call_static(&r, 1084 klass, 1085 vmSymbols::setProperty_name(), 1086 vmSymbols::string_string_string_signature(), 1087 key_str, 1088 value_str, 1089 CHECK); 1090 } 1091 1092 1093 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 1094 bool daemon, TRAPS) { 1095 assert(thread_group.not_null(), "thread group should be specified"); 1096 assert(threadObj() == NULL, "should only create Java thread object once"); 1097 1098 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1099 InstanceKlass* ik = InstanceKlass::cast(k); 1100 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK); 1101 1102 java_lang_Thread::set_thread(thread_oop(), this); 1103 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1104 set_threadObj(thread_oop()); 1105 1106 JavaValue result(T_VOID); 1107 if (thread_name != NULL) { 1108 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1109 // Thread gets assigned specified name and null target 1110 JavaCalls::call_special(&result, 1111 thread_oop, 1112 ik, 1113 vmSymbols::object_initializer_name(), 1114 vmSymbols::threadgroup_string_void_signature(), 1115 thread_group, // Argument 1 1116 name, // Argument 2 1117 THREAD); 1118 } else { 1119 // Thread gets assigned name "Thread-nnn" and null target 1120 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1121 JavaCalls::call_special(&result, 1122 thread_oop, 1123 ik, 1124 vmSymbols::object_initializer_name(), 1125 vmSymbols::threadgroup_runnable_void_signature(), 1126 thread_group, // Argument 1 1127 Handle(), // Argument 2 1128 THREAD); 1129 } 1130 1131 1132 if (daemon) { 1133 java_lang_Thread::set_daemon(thread_oop()); 1134 } 1135 1136 if (HAS_PENDING_EXCEPTION) { 1137 return; 1138 } 1139 1140 Klass* group = SystemDictionary::ThreadGroup_klass(); 1141 Handle threadObj(THREAD, this->threadObj()); 1142 1143 JavaCalls::call_special(&result, 1144 thread_group, 1145 group, 1146 vmSymbols::add_method_name(), 1147 vmSymbols::thread_void_signature(), 1148 threadObj, // Arg 1 1149 THREAD); 1150 } 1151 1152 // NamedThread -- non-JavaThread subclasses with multiple 1153 // uniquely named instances should derive from this. 1154 NamedThread::NamedThread() : Thread() { 1155 _name = NULL; 1156 _processed_thread = NULL; 1157 _gc_id = GCId::undefined(); 1158 } 1159 1160 NamedThread::~NamedThread() { 1161 if (_name != NULL) { 1162 FREE_C_HEAP_ARRAY(char, _name); 1163 _name = NULL; 1164 } 1165 } 1166 1167 void NamedThread::set_name(const char* format, ...) { 1168 guarantee(_name == NULL, "Only get to set name once."); 1169 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1170 guarantee(_name != NULL, "alloc failure"); 1171 va_list ap; 1172 va_start(ap, format); 1173 jio_vsnprintf(_name, max_name_len, format, ap); 1174 va_end(ap); 1175 } 1176 1177 void NamedThread::initialize_named_thread() { 1178 set_native_thread_name(name()); 1179 } 1180 1181 void NamedThread::print_on(outputStream* st) const { 1182 st->print("\"%s\" ", name()); 1183 Thread::print_on(st); 1184 st->cr(); 1185 } 1186 1187 1188 // ======= WatcherThread ======== 1189 1190 // The watcher thread exists to simulate timer interrupts. It should 1191 // be replaced by an abstraction over whatever native support for 1192 // timer interrupts exists on the platform. 1193 1194 WatcherThread* WatcherThread::_watcher_thread = NULL; 1195 bool WatcherThread::_startable = false; 1196 volatile bool WatcherThread::_should_terminate = false; 1197 1198 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1199 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1200 if (os::create_thread(this, os::watcher_thread)) { 1201 _watcher_thread = this; 1202 1203 // Set the watcher thread to the highest OS priority which should not be 1204 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1205 // is created. The only normal thread using this priority is the reference 1206 // handler thread, which runs for very short intervals only. 1207 // If the VMThread's priority is not lower than the WatcherThread profiling 1208 // will be inaccurate. 1209 os::set_priority(this, MaxPriority); 1210 if (!DisableStartThread) { 1211 os::start_thread(this); 1212 } 1213 } 1214 } 1215 1216 int WatcherThread::sleep() const { 1217 // The WatcherThread does not participate in the safepoint protocol 1218 // for the PeriodicTask_lock because it is not a JavaThread. 1219 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1220 1221 if (_should_terminate) { 1222 // check for termination before we do any housekeeping or wait 1223 return 0; // we did not sleep. 1224 } 1225 1226 // remaining will be zero if there are no tasks, 1227 // causing the WatcherThread to sleep until a task is 1228 // enrolled 1229 int remaining = PeriodicTask::time_to_wait(); 1230 int time_slept = 0; 1231 1232 // we expect this to timeout - we only ever get unparked when 1233 // we should terminate or when a new task has been enrolled 1234 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1235 1236 jlong time_before_loop = os::javaTimeNanos(); 1237 1238 while (true) { 1239 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, 1240 remaining); 1241 jlong now = os::javaTimeNanos(); 1242 1243 if (remaining == 0) { 1244 // if we didn't have any tasks we could have waited for a long time 1245 // consider the time_slept zero and reset time_before_loop 1246 time_slept = 0; 1247 time_before_loop = now; 1248 } else { 1249 // need to recalculate since we might have new tasks in _tasks 1250 time_slept = (int) ((now - time_before_loop) / 1000000); 1251 } 1252 1253 // Change to task list or spurious wakeup of some kind 1254 if (timedout || _should_terminate) { 1255 break; 1256 } 1257 1258 remaining = PeriodicTask::time_to_wait(); 1259 if (remaining == 0) { 1260 // Last task was just disenrolled so loop around and wait until 1261 // another task gets enrolled 1262 continue; 1263 } 1264 1265 remaining -= time_slept; 1266 if (remaining <= 0) { 1267 break; 1268 } 1269 } 1270 1271 return time_slept; 1272 } 1273 1274 void WatcherThread::run() { 1275 assert(this == watcher_thread(), "just checking"); 1276 1277 this->record_stack_base_and_size(); 1278 this->set_native_thread_name(this->name()); 1279 this->set_active_handles(JNIHandleBlock::allocate_block()); 1280 while (true) { 1281 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1282 assert(watcher_thread() == this, "thread consistency check"); 1283 1284 // Calculate how long it'll be until the next PeriodicTask work 1285 // should be done, and sleep that amount of time. 1286 int time_waited = sleep(); 1287 1288 if (is_error_reported()) { 1289 // A fatal error has happened, the error handler(VMError::report_and_die) 1290 // should abort JVM after creating an error log file. However in some 1291 // rare cases, the error handler itself might deadlock. Here periodically 1292 // check for error reporting timeouts, and if it happens, just proceed to 1293 // abort the VM. 1294 1295 // This code is in WatcherThread because WatcherThread wakes up 1296 // periodically so the fatal error handler doesn't need to do anything; 1297 // also because the WatcherThread is less likely to crash than other 1298 // threads. 1299 1300 for (;;) { 1301 // Note: we use naked sleep in this loop because we want to avoid using 1302 // any kind of VM infrastructure which may be broken at this point. 1303 if (VMError::check_timeout()) { 1304 // We hit error reporting timeout. Error reporting was interrupted and 1305 // will be wrapping things up now (closing files etc). Give it some more 1306 // time, then quit the VM. 1307 os::naked_short_sleep(200); 1308 // Print a message to stderr. 1309 fdStream err(defaultStream::output_fd()); 1310 err.print_raw_cr("# [ timer expired, abort... ]"); 1311 // skip atexit/vm_exit/vm_abort hooks 1312 os::die(); 1313 } 1314 1315 // Wait a second, then recheck for timeout. 1316 os::naked_short_sleep(999); 1317 } 1318 } 1319 1320 if (_should_terminate) { 1321 // check for termination before posting the next tick 1322 break; 1323 } 1324 1325 PeriodicTask::real_time_tick(time_waited); 1326 } 1327 1328 // Signal that it is terminated 1329 { 1330 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1331 _watcher_thread = NULL; 1332 Terminator_lock->notify(); 1333 } 1334 } 1335 1336 void WatcherThread::start() { 1337 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1338 1339 if (watcher_thread() == NULL && _startable) { 1340 _should_terminate = false; 1341 // Create the single instance of WatcherThread 1342 new WatcherThread(); 1343 } 1344 } 1345 1346 void WatcherThread::make_startable() { 1347 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1348 _startable = true; 1349 } 1350 1351 void WatcherThread::stop() { 1352 { 1353 // Follow normal safepoint aware lock enter protocol since the 1354 // WatcherThread is stopped by another JavaThread. 1355 MutexLocker ml(PeriodicTask_lock); 1356 _should_terminate = true; 1357 1358 WatcherThread* watcher = watcher_thread(); 1359 if (watcher != NULL) { 1360 // unpark the WatcherThread so it can see that it should terminate 1361 watcher->unpark(); 1362 } 1363 } 1364 1365 MutexLocker mu(Terminator_lock); 1366 1367 while (watcher_thread() != NULL) { 1368 // This wait should make safepoint checks, wait without a timeout, 1369 // and wait as a suspend-equivalent condition. 1370 // 1371 // Note: If the FlatProfiler is running, then this thread is waiting 1372 // for the WatcherThread to terminate and the WatcherThread, via the 1373 // FlatProfiler task, is waiting for the external suspend request on 1374 // this thread to complete. wait_for_ext_suspend_completion() will 1375 // eventually timeout, but that takes time. Making this wait a 1376 // suspend-equivalent condition solves that timeout problem. 1377 // 1378 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1379 Mutex::_as_suspend_equivalent_flag); 1380 } 1381 } 1382 1383 void WatcherThread::unpark() { 1384 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1385 PeriodicTask_lock->notify(); 1386 } 1387 1388 void WatcherThread::print_on(outputStream* st) const { 1389 st->print("\"%s\" ", name()); 1390 Thread::print_on(st); 1391 st->cr(); 1392 } 1393 1394 // ======= JavaThread ======== 1395 1396 #if INCLUDE_JVMCI 1397 1398 jlong* JavaThread::_jvmci_old_thread_counters; 1399 1400 bool jvmci_counters_include(JavaThread* thread) { 1401 oop threadObj = thread->threadObj(); 1402 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); 1403 } 1404 1405 void JavaThread::collect_counters(typeArrayOop array) { 1406 if (JVMCICounterSize > 0) { 1407 MutexLocker tl(Threads_lock); 1408 for (int i = 0; i < array->length(); i++) { 1409 array->long_at_put(i, _jvmci_old_thread_counters[i]); 1410 } 1411 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) { 1412 if (jvmci_counters_include(tp)) { 1413 for (int i = 0; i < array->length(); i++) { 1414 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]); 1415 } 1416 } 1417 } 1418 } 1419 } 1420 1421 #endif // INCLUDE_JVMCI 1422 1423 // A JavaThread is a normal Java thread 1424 1425 void JavaThread::initialize() { 1426 // Initialize fields 1427 1428 set_saved_exception_pc(NULL); 1429 set_threadObj(NULL); 1430 _anchor.clear(); 1431 set_entry_point(NULL); 1432 set_jni_functions(jni_functions()); 1433 set_callee_target(NULL); 1434 set_vm_result(NULL); 1435 set_vm_result_2(NULL); 1436 set_vframe_array_head(NULL); 1437 set_vframe_array_last(NULL); 1438 set_deferred_locals(NULL); 1439 set_deopt_mark(NULL); 1440 set_deopt_compiled_method(NULL); 1441 clear_must_deopt_id(); 1442 set_monitor_chunks(NULL); 1443 set_next(NULL); 1444 set_thread_state(_thread_new); 1445 _terminated = _not_terminated; 1446 _privileged_stack_top = NULL; 1447 _array_for_gc = NULL; 1448 _suspend_equivalent = false; 1449 _in_deopt_handler = 0; 1450 _doing_unsafe_access = false; 1451 _stack_guard_state = stack_guard_unused; 1452 #if INCLUDE_JVMCI 1453 _pending_monitorenter = false; 1454 _pending_deoptimization = -1; 1455 _pending_failed_speculation = NULL; 1456 _pending_transfer_to_interpreter = false; 1457 _adjusting_comp_level = false; 1458 _jvmci._alternate_call_target = NULL; 1459 assert(_jvmci._implicit_exception_pc == NULL, "must be"); 1460 if (JVMCICounterSize > 0) { 1461 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 1462 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize); 1463 } else { 1464 _jvmci_counters = NULL; 1465 } 1466 #endif // INCLUDE_JVMCI 1467 _reserved_stack_activation = NULL; // stack base not known yet 1468 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1469 _exception_pc = 0; 1470 _exception_handler_pc = 0; 1471 _is_method_handle_return = 0; 1472 _jvmti_thread_state= NULL; 1473 _should_post_on_exceptions_flag = JNI_FALSE; 1474 _jvmti_get_loaded_classes_closure = NULL; 1475 _interp_only_mode = 0; 1476 _special_runtime_exit_condition = _no_async_condition; 1477 _pending_async_exception = NULL; 1478 _thread_stat = NULL; 1479 _thread_stat = new ThreadStatistics(); 1480 _blocked_on_compilation = false; 1481 _jni_active_critical = 0; 1482 _pending_jni_exception_check_fn = NULL; 1483 _do_not_unlock_if_synchronized = false; 1484 _cached_monitor_info = NULL; 1485 _parker = Parker::Allocate(this); 1486 1487 #ifndef PRODUCT 1488 _jmp_ring_index = 0; 1489 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1490 record_jump(NULL, NULL, NULL, 0); 1491 } 1492 #endif // PRODUCT 1493 1494 set_thread_profiler(NULL); 1495 if (FlatProfiler::is_active()) { 1496 // This is where we would decide to either give each thread it's own profiler 1497 // or use one global one from FlatProfiler, 1498 // or up to some count of the number of profiled threads, etc. 1499 ThreadProfiler* pp = new ThreadProfiler(); 1500 pp->engage(); 1501 set_thread_profiler(pp); 1502 } 1503 1504 // Setup safepoint state info for this thread 1505 ThreadSafepointState::create(this); 1506 1507 debug_only(_java_call_counter = 0); 1508 1509 // JVMTI PopFrame support 1510 _popframe_condition = popframe_inactive; 1511 _popframe_preserved_args = NULL; 1512 _popframe_preserved_args_size = 0; 1513 _frames_to_pop_failed_realloc = 0; 1514 1515 pd_initialize(); 1516 } 1517 1518 JavaThread::JavaThread(bool is_attaching_via_jni) : 1519 Thread() 1520 { 1521 initialize(); 1522 if (is_attaching_via_jni) { 1523 _jni_attach_state = _attaching_via_jni; 1524 } else { 1525 _jni_attach_state = _not_attaching_via_jni; 1526 } 1527 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1528 } 1529 1530 bool JavaThread::reguard_stack(address cur_sp) { 1531 if (_stack_guard_state != stack_guard_yellow_reserved_disabled 1532 && _stack_guard_state != stack_guard_reserved_disabled) { 1533 return true; // Stack already guarded or guard pages not needed. 1534 } 1535 1536 if (register_stack_overflow()) { 1537 // For those architectures which have separate register and 1538 // memory stacks, we must check the register stack to see if 1539 // it has overflowed. 1540 return false; 1541 } 1542 1543 // Java code never executes within the yellow zone: the latter is only 1544 // there to provoke an exception during stack banging. If java code 1545 // is executing there, either StackShadowPages should be larger, or 1546 // some exception code in c1, c2 or the interpreter isn't unwinding 1547 // when it should. 1548 guarantee(cur_sp > stack_reserved_zone_base(), 1549 "not enough space to reguard - increase StackShadowPages"); 1550 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) { 1551 enable_stack_yellow_reserved_zone(); 1552 if (reserved_stack_activation() != stack_base()) { 1553 set_reserved_stack_activation(stack_base()); 1554 } 1555 } else if (_stack_guard_state == stack_guard_reserved_disabled) { 1556 set_reserved_stack_activation(stack_base()); 1557 enable_stack_reserved_zone(); 1558 } 1559 return true; 1560 } 1561 1562 bool JavaThread::reguard_stack(void) { 1563 return reguard_stack(os::current_stack_pointer()); 1564 } 1565 1566 1567 void JavaThread::block_if_vm_exited() { 1568 if (_terminated == _vm_exited) { 1569 // _vm_exited is set at safepoint, and Threads_lock is never released 1570 // we will block here forever 1571 Threads_lock->lock_without_safepoint_check(); 1572 ShouldNotReachHere(); 1573 } 1574 } 1575 1576 1577 // Remove this ifdef when C1 is ported to the compiler interface. 1578 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1579 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1580 1581 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1582 Thread() 1583 { 1584 initialize(); 1585 _jni_attach_state = _not_attaching_via_jni; 1586 set_entry_point(entry_point); 1587 // Create the native thread itself. 1588 // %note runtime_23 1589 os::ThreadType thr_type = os::java_thread; 1590 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1591 os::java_thread; 1592 os::create_thread(this, thr_type, stack_sz); 1593 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1594 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1595 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1596 // the exception consists of creating the exception object & initializing it, initialization 1597 // will leave the VM via a JavaCall and then all locks must be unlocked). 1598 // 1599 // The thread is still suspended when we reach here. Thread must be explicit started 1600 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1601 // by calling Threads:add. The reason why this is not done here, is because the thread 1602 // object must be fully initialized (take a look at JVM_Start) 1603 } 1604 1605 JavaThread::~JavaThread() { 1606 1607 // JSR166 -- return the parker to the free list 1608 Parker::Release(_parker); 1609 _parker = NULL; 1610 1611 // Free any remaining previous UnrollBlock 1612 vframeArray* old_array = vframe_array_last(); 1613 1614 if (old_array != NULL) { 1615 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1616 old_array->set_unroll_block(NULL); 1617 delete old_info; 1618 delete old_array; 1619 } 1620 1621 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1622 if (deferred != NULL) { 1623 // This can only happen if thread is destroyed before deoptimization occurs. 1624 assert(deferred->length() != 0, "empty array!"); 1625 do { 1626 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1627 deferred->remove_at(0); 1628 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1629 delete dlv; 1630 } while (deferred->length() != 0); 1631 delete deferred; 1632 } 1633 1634 // All Java related clean up happens in exit 1635 ThreadSafepointState::destroy(this); 1636 if (_thread_profiler != NULL) delete _thread_profiler; 1637 if (_thread_stat != NULL) delete _thread_stat; 1638 1639 #if INCLUDE_JVMCI 1640 if (JVMCICounterSize > 0) { 1641 if (jvmci_counters_include(this)) { 1642 for (int i = 0; i < JVMCICounterSize; i++) { 1643 _jvmci_old_thread_counters[i] += _jvmci_counters[i]; 1644 } 1645 } 1646 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); 1647 } 1648 #endif // INCLUDE_JVMCI 1649 } 1650 1651 1652 // The first routine called by a new Java thread 1653 void JavaThread::run() { 1654 // initialize thread-local alloc buffer related fields 1655 this->initialize_tlab(); 1656 1657 // used to test validity of stack trace backs 1658 this->record_base_of_stack_pointer(); 1659 1660 // Record real stack base and size. 1661 this->record_stack_base_and_size(); 1662 1663 this->create_stack_guard_pages(); 1664 1665 this->cache_global_variables(); 1666 1667 // Thread is now sufficient initialized to be handled by the safepoint code as being 1668 // in the VM. Change thread state from _thread_new to _thread_in_vm 1669 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1670 1671 assert(JavaThread::current() == this, "sanity check"); 1672 assert(!Thread::current()->owns_locks(), "sanity check"); 1673 1674 DTRACE_THREAD_PROBE(start, this); 1675 1676 // This operation might block. We call that after all safepoint checks for a new thread has 1677 // been completed. 1678 this->set_active_handles(JNIHandleBlock::allocate_block()); 1679 1680 if (JvmtiExport::should_post_thread_life()) { 1681 JvmtiExport::post_thread_start(this); 1682 } 1683 1684 EventThreadStart event; 1685 if (event.should_commit()) { 1686 event.set_thread(THREAD_TRACE_ID(this)); 1687 event.commit(); 1688 } 1689 1690 // We call another function to do the rest so we are sure that the stack addresses used 1691 // from there will be lower than the stack base just computed 1692 thread_main_inner(); 1693 1694 // Note, thread is no longer valid at this point! 1695 } 1696 1697 1698 void JavaThread::thread_main_inner() { 1699 assert(JavaThread::current() == this, "sanity check"); 1700 assert(this->threadObj() != NULL, "just checking"); 1701 1702 // Execute thread entry point unless this thread has a pending exception 1703 // or has been stopped before starting. 1704 // Note: Due to JVM_StopThread we can have pending exceptions already! 1705 if (!this->has_pending_exception() && 1706 !java_lang_Thread::is_stillborn(this->threadObj())) { 1707 { 1708 ResourceMark rm(this); 1709 this->set_native_thread_name(this->get_thread_name()); 1710 } 1711 HandleMark hm(this); 1712 this->entry_point()(this, this); 1713 } 1714 1715 DTRACE_THREAD_PROBE(stop, this); 1716 1717 this->exit(false); 1718 delete this; 1719 } 1720 1721 1722 static void ensure_join(JavaThread* thread) { 1723 // We do not need to grap the Threads_lock, since we are operating on ourself. 1724 Handle threadObj(thread, thread->threadObj()); 1725 assert(threadObj.not_null(), "java thread object must exist"); 1726 ObjectLocker lock(threadObj, thread); 1727 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1728 thread->clear_pending_exception(); 1729 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1730 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1731 // Clear the native thread instance - this makes isAlive return false and allows the join() 1732 // to complete once we've done the notify_all below 1733 java_lang_Thread::set_thread(threadObj(), NULL); 1734 lock.notify_all(thread); 1735 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1736 thread->clear_pending_exception(); 1737 } 1738 1739 1740 // For any new cleanup additions, please check to see if they need to be applied to 1741 // cleanup_failed_attach_current_thread as well. 1742 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1743 assert(this == JavaThread::current(), "thread consistency check"); 1744 1745 HandleMark hm(this); 1746 Handle uncaught_exception(this, this->pending_exception()); 1747 this->clear_pending_exception(); 1748 Handle threadObj(this, this->threadObj()); 1749 assert(threadObj.not_null(), "Java thread object should be created"); 1750 1751 if (get_thread_profiler() != NULL) { 1752 get_thread_profiler()->disengage(); 1753 ResourceMark rm; 1754 get_thread_profiler()->print(get_thread_name()); 1755 } 1756 1757 1758 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1759 { 1760 EXCEPTION_MARK; 1761 1762 CLEAR_PENDING_EXCEPTION; 1763 } 1764 if (!destroy_vm) { 1765 if (uncaught_exception.not_null()) { 1766 EXCEPTION_MARK; 1767 // Call method Thread.dispatchUncaughtException(). 1768 Klass* thread_klass = SystemDictionary::Thread_klass(); 1769 JavaValue result(T_VOID); 1770 JavaCalls::call_virtual(&result, 1771 threadObj, thread_klass, 1772 vmSymbols::dispatchUncaughtException_name(), 1773 vmSymbols::throwable_void_signature(), 1774 uncaught_exception, 1775 THREAD); 1776 if (HAS_PENDING_EXCEPTION) { 1777 ResourceMark rm(this); 1778 jio_fprintf(defaultStream::error_stream(), 1779 "\nException: %s thrown from the UncaughtExceptionHandler" 1780 " in thread \"%s\"\n", 1781 pending_exception()->klass()->external_name(), 1782 get_thread_name()); 1783 CLEAR_PENDING_EXCEPTION; 1784 } 1785 } 1786 1787 // Called before the java thread exit since we want to read info 1788 // from java_lang_Thread object 1789 EventThreadEnd event; 1790 if (event.should_commit()) { 1791 event.set_thread(THREAD_TRACE_ID(this)); 1792 event.commit(); 1793 } 1794 1795 // Call after last event on thread 1796 EVENT_THREAD_EXIT(this); 1797 1798 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1799 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1800 // is deprecated anyhow. 1801 if (!is_Compiler_thread()) { 1802 int count = 3; 1803 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1804 EXCEPTION_MARK; 1805 JavaValue result(T_VOID); 1806 Klass* thread_klass = SystemDictionary::Thread_klass(); 1807 JavaCalls::call_virtual(&result, 1808 threadObj, thread_klass, 1809 vmSymbols::exit_method_name(), 1810 vmSymbols::void_method_signature(), 1811 THREAD); 1812 CLEAR_PENDING_EXCEPTION; 1813 } 1814 } 1815 // notify JVMTI 1816 if (JvmtiExport::should_post_thread_life()) { 1817 JvmtiExport::post_thread_end(this); 1818 } 1819 1820 // We have notified the agents that we are exiting, before we go on, 1821 // we must check for a pending external suspend request and honor it 1822 // in order to not surprise the thread that made the suspend request. 1823 while (true) { 1824 { 1825 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1826 if (!is_external_suspend()) { 1827 set_terminated(_thread_exiting); 1828 ThreadService::current_thread_exiting(this); 1829 break; 1830 } 1831 // Implied else: 1832 // Things get a little tricky here. We have a pending external 1833 // suspend request, but we are holding the SR_lock so we 1834 // can't just self-suspend. So we temporarily drop the lock 1835 // and then self-suspend. 1836 } 1837 1838 ThreadBlockInVM tbivm(this); 1839 java_suspend_self(); 1840 1841 // We're done with this suspend request, but we have to loop around 1842 // and check again. Eventually we will get SR_lock without a pending 1843 // external suspend request and will be able to mark ourselves as 1844 // exiting. 1845 } 1846 // no more external suspends are allowed at this point 1847 } else { 1848 // before_exit() has already posted JVMTI THREAD_END events 1849 } 1850 1851 // Notify waiters on thread object. This has to be done after exit() is called 1852 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1853 // group should have the destroyed bit set before waiters are notified). 1854 ensure_join(this); 1855 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1856 1857 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1858 // held by this thread must be released. The spec does not distinguish 1859 // between JNI-acquired and regular Java monitors. We can only see 1860 // regular Java monitors here if monitor enter-exit matching is broken. 1861 // 1862 // Optionally release any monitors for regular JavaThread exits. This 1863 // is provided as a work around for any bugs in monitor enter-exit 1864 // matching. This can be expensive so it is not enabled by default. 1865 // 1866 // ensure_join() ignores IllegalThreadStateExceptions, and so does 1867 // ObjectSynchronizer::release_monitors_owned_by_thread(). 1868 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) { 1869 // Sanity check even though JNI DetachCurrentThread() would have 1870 // returned JNI_ERR if there was a Java frame. JavaThread exit 1871 // should be done executing Java code by the time we get here. 1872 assert(!this->has_last_Java_frame(), 1873 "should not have a Java frame when detaching or exiting"); 1874 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1875 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1876 } 1877 1878 // These things needs to be done while we are still a Java Thread. Make sure that thread 1879 // is in a consistent state, in case GC happens 1880 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1881 1882 if (active_handles() != NULL) { 1883 JNIHandleBlock* block = active_handles(); 1884 set_active_handles(NULL); 1885 JNIHandleBlock::release_block(block); 1886 } 1887 1888 if (free_handle_block() != NULL) { 1889 JNIHandleBlock* block = free_handle_block(); 1890 set_free_handle_block(NULL); 1891 JNIHandleBlock::release_block(block); 1892 } 1893 1894 // These have to be removed while this is still a valid thread. 1895 remove_stack_guard_pages(); 1896 1897 if (UseTLAB) { 1898 tlab().make_parsable(true); // retire TLAB 1899 } 1900 1901 if (JvmtiEnv::environments_might_exist()) { 1902 JvmtiExport::cleanup_thread(this); 1903 } 1904 1905 BarrierSet *bs = Universe::heap()->barrier_set(); 1906 bs->on_destroy_thread(this); 1907 1908 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").", 1909 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", 1910 os::current_thread_id()); 1911 1912 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1913 Threads::remove(this); 1914 } 1915 1916 void JavaThread::cleanup_failed_attach_current_thread() { 1917 if (get_thread_profiler() != NULL) { 1918 get_thread_profiler()->disengage(); 1919 ResourceMark rm; 1920 get_thread_profiler()->print(get_thread_name()); 1921 } 1922 1923 if (active_handles() != NULL) { 1924 JNIHandleBlock* block = active_handles(); 1925 set_active_handles(NULL); 1926 JNIHandleBlock::release_block(block); 1927 } 1928 1929 if (free_handle_block() != NULL) { 1930 JNIHandleBlock* block = free_handle_block(); 1931 set_free_handle_block(NULL); 1932 JNIHandleBlock::release_block(block); 1933 } 1934 1935 // These have to be removed while this is still a valid thread. 1936 remove_stack_guard_pages(); 1937 1938 if (UseTLAB) { 1939 tlab().make_parsable(true); // retire TLAB, if any 1940 } 1941 1942 BarrierSet *bs = Universe::heap()->barrier_set(); 1943 bs->on_destroy_thread(this); 1944 1945 Threads::remove(this); 1946 delete this; 1947 } 1948 1949 1950 1951 1952 JavaThread* JavaThread::active() { 1953 Thread* thread = Thread::current(); 1954 if (thread->is_Java_thread()) { 1955 return (JavaThread*) thread; 1956 } else { 1957 assert(thread->is_VM_thread(), "this must be a vm thread"); 1958 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1959 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1960 assert(ret->is_Java_thread(), "must be a Java thread"); 1961 return ret; 1962 } 1963 } 1964 1965 bool JavaThread::is_lock_owned(address adr) const { 1966 if (Thread::is_lock_owned(adr)) return true; 1967 1968 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1969 if (chunk->contains(adr)) return true; 1970 } 1971 1972 return false; 1973 } 1974 1975 1976 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1977 chunk->set_next(monitor_chunks()); 1978 set_monitor_chunks(chunk); 1979 } 1980 1981 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1982 guarantee(monitor_chunks() != NULL, "must be non empty"); 1983 if (monitor_chunks() == chunk) { 1984 set_monitor_chunks(chunk->next()); 1985 } else { 1986 MonitorChunk* prev = monitor_chunks(); 1987 while (prev->next() != chunk) prev = prev->next(); 1988 prev->set_next(chunk->next()); 1989 } 1990 } 1991 1992 // JVM support. 1993 1994 // Note: this function shouldn't block if it's called in 1995 // _thread_in_native_trans state (such as from 1996 // check_special_condition_for_native_trans()). 1997 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 1998 1999 if (has_last_Java_frame() && has_async_condition()) { 2000 // If we are at a polling page safepoint (not a poll return) 2001 // then we must defer async exception because live registers 2002 // will be clobbered by the exception path. Poll return is 2003 // ok because the call we a returning from already collides 2004 // with exception handling registers and so there is no issue. 2005 // (The exception handling path kills call result registers but 2006 // this is ok since the exception kills the result anyway). 2007 2008 if (is_at_poll_safepoint()) { 2009 // if the code we are returning to has deoptimized we must defer 2010 // the exception otherwise live registers get clobbered on the 2011 // exception path before deoptimization is able to retrieve them. 2012 // 2013 RegisterMap map(this, false); 2014 frame caller_fr = last_frame().sender(&map); 2015 assert(caller_fr.is_compiled_frame(), "what?"); 2016 if (caller_fr.is_deoptimized_frame()) { 2017 log_info(exceptions)("deferred async exception at compiled safepoint"); 2018 return; 2019 } 2020 } 2021 } 2022 2023 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2024 if (condition == _no_async_condition) { 2025 // Conditions have changed since has_special_runtime_exit_condition() 2026 // was called: 2027 // - if we were here only because of an external suspend request, 2028 // then that was taken care of above (or cancelled) so we are done 2029 // - if we were here because of another async request, then it has 2030 // been cleared between the has_special_runtime_exit_condition() 2031 // and now so again we are done 2032 return; 2033 } 2034 2035 // Check for pending async. exception 2036 if (_pending_async_exception != NULL) { 2037 // Only overwrite an already pending exception, if it is not a threadDeath. 2038 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2039 2040 // We cannot call Exceptions::_throw(...) here because we cannot block 2041 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2042 2043 if (log_is_enabled(Info, exceptions)) { 2044 ResourceMark rm; 2045 outputStream* logstream = Log(exceptions)::info_stream(); 2046 logstream->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); 2047 if (has_last_Java_frame()) { 2048 frame f = last_frame(); 2049 logstream->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); 2050 } 2051 logstream->print_cr(" of type: %s", _pending_async_exception->klass()->external_name()); 2052 } 2053 _pending_async_exception = NULL; 2054 clear_has_async_exception(); 2055 } 2056 } 2057 2058 if (check_unsafe_error && 2059 condition == _async_unsafe_access_error && !has_pending_exception()) { 2060 condition = _no_async_condition; // done 2061 switch (thread_state()) { 2062 case _thread_in_vm: { 2063 JavaThread* THREAD = this; 2064 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2065 } 2066 case _thread_in_native: { 2067 ThreadInVMfromNative tiv(this); 2068 JavaThread* THREAD = this; 2069 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2070 } 2071 case _thread_in_Java: { 2072 ThreadInVMfromJava tiv(this); 2073 JavaThread* THREAD = this; 2074 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2075 } 2076 default: 2077 ShouldNotReachHere(); 2078 } 2079 } 2080 2081 assert(condition == _no_async_condition || has_pending_exception() || 2082 (!check_unsafe_error && condition == _async_unsafe_access_error), 2083 "must have handled the async condition, if no exception"); 2084 } 2085 2086 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2087 // 2088 // Check for pending external suspend. Internal suspend requests do 2089 // not use handle_special_runtime_exit_condition(). 2090 // If JNIEnv proxies are allowed, don't self-suspend if the target 2091 // thread is not the current thread. In older versions of jdbx, jdbx 2092 // threads could call into the VM with another thread's JNIEnv so we 2093 // can be here operating on behalf of a suspended thread (4432884). 2094 bool do_self_suspend = is_external_suspend_with_lock(); 2095 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2096 // 2097 // Because thread is external suspended the safepoint code will count 2098 // thread as at a safepoint. This can be odd because we can be here 2099 // as _thread_in_Java which would normally transition to _thread_blocked 2100 // at a safepoint. We would like to mark the thread as _thread_blocked 2101 // before calling java_suspend_self like all other callers of it but 2102 // we must then observe proper safepoint protocol. (We can't leave 2103 // _thread_blocked with a safepoint in progress). However we can be 2104 // here as _thread_in_native_trans so we can't use a normal transition 2105 // constructor/destructor pair because they assert on that type of 2106 // transition. We could do something like: 2107 // 2108 // JavaThreadState state = thread_state(); 2109 // set_thread_state(_thread_in_vm); 2110 // { 2111 // ThreadBlockInVM tbivm(this); 2112 // java_suspend_self() 2113 // } 2114 // set_thread_state(_thread_in_vm_trans); 2115 // if (safepoint) block; 2116 // set_thread_state(state); 2117 // 2118 // but that is pretty messy. Instead we just go with the way the 2119 // code has worked before and note that this is the only path to 2120 // java_suspend_self that doesn't put the thread in _thread_blocked 2121 // mode. 2122 2123 frame_anchor()->make_walkable(this); 2124 java_suspend_self(); 2125 2126 // We might be here for reasons in addition to the self-suspend request 2127 // so check for other async requests. 2128 } 2129 2130 if (check_asyncs) { 2131 check_and_handle_async_exceptions(); 2132 } 2133 } 2134 2135 void JavaThread::send_thread_stop(oop java_throwable) { 2136 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2137 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2138 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2139 2140 // Do not throw asynchronous exceptions against the compiler thread 2141 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2142 if (!can_call_java()) return; 2143 2144 { 2145 // Actually throw the Throwable against the target Thread - however 2146 // only if there is no thread death exception installed already. 2147 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2148 // If the topmost frame is a runtime stub, then we are calling into 2149 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2150 // must deoptimize the caller before continuing, as the compiled exception handler table 2151 // may not be valid 2152 if (has_last_Java_frame()) { 2153 frame f = last_frame(); 2154 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2155 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2156 RegisterMap reg_map(this, UseBiasedLocking); 2157 frame compiled_frame = f.sender(®_map); 2158 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2159 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2160 } 2161 } 2162 } 2163 2164 // Set async. pending exception in thread. 2165 set_pending_async_exception(java_throwable); 2166 2167 if (log_is_enabled(Info, exceptions)) { 2168 ResourceMark rm; 2169 log_info(exceptions)("Pending Async. exception installed of type: %s", 2170 InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2171 } 2172 // for AbortVMOnException flag 2173 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name()); 2174 } 2175 } 2176 2177 2178 // Interrupt thread so it will wake up from a potential wait() 2179 Thread::interrupt(this); 2180 } 2181 2182 // External suspension mechanism. 2183 // 2184 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2185 // to any VM_locks and it is at a transition 2186 // Self-suspension will happen on the transition out of the vm. 2187 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2188 // 2189 // Guarantees on return: 2190 // + Target thread will not execute any new bytecode (that's why we need to 2191 // force a safepoint) 2192 // + Target thread will not enter any new monitors 2193 // 2194 void JavaThread::java_suspend() { 2195 { MutexLocker mu(Threads_lock); 2196 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2197 return; 2198 } 2199 } 2200 2201 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2202 if (!is_external_suspend()) { 2203 // a racing resume has cancelled us; bail out now 2204 return; 2205 } 2206 2207 // suspend is done 2208 uint32_t debug_bits = 0; 2209 // Warning: is_ext_suspend_completed() may temporarily drop the 2210 // SR_lock to allow the thread to reach a stable thread state if 2211 // it is currently in a transient thread state. 2212 if (is_ext_suspend_completed(false /* !called_by_wait */, 2213 SuspendRetryDelay, &debug_bits)) { 2214 return; 2215 } 2216 } 2217 2218 VM_ForceSafepoint vm_suspend; 2219 VMThread::execute(&vm_suspend); 2220 } 2221 2222 // Part II of external suspension. 2223 // A JavaThread self suspends when it detects a pending external suspend 2224 // request. This is usually on transitions. It is also done in places 2225 // where continuing to the next transition would surprise the caller, 2226 // e.g., monitor entry. 2227 // 2228 // Returns the number of times that the thread self-suspended. 2229 // 2230 // Note: DO NOT call java_suspend_self() when you just want to block current 2231 // thread. java_suspend_self() is the second stage of cooperative 2232 // suspension for external suspend requests and should only be used 2233 // to complete an external suspend request. 2234 // 2235 int JavaThread::java_suspend_self() { 2236 int ret = 0; 2237 2238 // we are in the process of exiting so don't suspend 2239 if (is_exiting()) { 2240 clear_external_suspend(); 2241 return ret; 2242 } 2243 2244 assert(_anchor.walkable() || 2245 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2246 "must have walkable stack"); 2247 2248 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2249 2250 assert(!this->is_ext_suspended(), 2251 "a thread trying to self-suspend should not already be suspended"); 2252 2253 if (this->is_suspend_equivalent()) { 2254 // If we are self-suspending as a result of the lifting of a 2255 // suspend equivalent condition, then the suspend_equivalent 2256 // flag is not cleared until we set the ext_suspended flag so 2257 // that wait_for_ext_suspend_completion() returns consistent 2258 // results. 2259 this->clear_suspend_equivalent(); 2260 } 2261 2262 // A racing resume may have cancelled us before we grabbed SR_lock 2263 // above. Or another external suspend request could be waiting for us 2264 // by the time we return from SR_lock()->wait(). The thread 2265 // that requested the suspension may already be trying to walk our 2266 // stack and if we return now, we can change the stack out from under 2267 // it. This would be a "bad thing (TM)" and cause the stack walker 2268 // to crash. We stay self-suspended until there are no more pending 2269 // external suspend requests. 2270 while (is_external_suspend()) { 2271 ret++; 2272 this->set_ext_suspended(); 2273 2274 // _ext_suspended flag is cleared by java_resume() 2275 while (is_ext_suspended()) { 2276 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2277 } 2278 } 2279 2280 return ret; 2281 } 2282 2283 #ifdef ASSERT 2284 // verify the JavaThread has not yet been published in the Threads::list, and 2285 // hence doesn't need protection from concurrent access at this stage 2286 void JavaThread::verify_not_published() { 2287 if (!Threads_lock->owned_by_self()) { 2288 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2289 assert(!Threads::includes(this), 2290 "java thread shouldn't have been published yet!"); 2291 } else { 2292 assert(!Threads::includes(this), 2293 "java thread shouldn't have been published yet!"); 2294 } 2295 } 2296 #endif 2297 2298 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2299 // progress or when _suspend_flags is non-zero. 2300 // Current thread needs to self-suspend if there is a suspend request and/or 2301 // block if a safepoint is in progress. 2302 // Async exception ISN'T checked. 2303 // Note only the ThreadInVMfromNative transition can call this function 2304 // directly and when thread state is _thread_in_native_trans 2305 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2306 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2307 2308 JavaThread *curJT = JavaThread::current(); 2309 bool do_self_suspend = thread->is_external_suspend(); 2310 2311 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2312 2313 // If JNIEnv proxies are allowed, don't self-suspend if the target 2314 // thread is not the current thread. In older versions of jdbx, jdbx 2315 // threads could call into the VM with another thread's JNIEnv so we 2316 // can be here operating on behalf of a suspended thread (4432884). 2317 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2318 JavaThreadState state = thread->thread_state(); 2319 2320 // We mark this thread_blocked state as a suspend-equivalent so 2321 // that a caller to is_ext_suspend_completed() won't be confused. 2322 // The suspend-equivalent state is cleared by java_suspend_self(). 2323 thread->set_suspend_equivalent(); 2324 2325 // If the safepoint code sees the _thread_in_native_trans state, it will 2326 // wait until the thread changes to other thread state. There is no 2327 // guarantee on how soon we can obtain the SR_lock and complete the 2328 // self-suspend request. It would be a bad idea to let safepoint wait for 2329 // too long. Temporarily change the state to _thread_blocked to 2330 // let the VM thread know that this thread is ready for GC. The problem 2331 // of changing thread state is that safepoint could happen just after 2332 // java_suspend_self() returns after being resumed, and VM thread will 2333 // see the _thread_blocked state. We must check for safepoint 2334 // after restoring the state and make sure we won't leave while a safepoint 2335 // is in progress. 2336 thread->set_thread_state(_thread_blocked); 2337 thread->java_suspend_self(); 2338 thread->set_thread_state(state); 2339 // Make sure new state is seen by VM thread 2340 if (os::is_MP()) { 2341 if (UseMembar) { 2342 // Force a fence between the write above and read below 2343 OrderAccess::fence(); 2344 } else { 2345 // Must use this rather than serialization page in particular on Windows 2346 InterfaceSupport::serialize_memory(thread); 2347 } 2348 } 2349 } 2350 2351 if (SafepointSynchronize::do_call_back()) { 2352 // If we are safepointing, then block the caller which may not be 2353 // the same as the target thread (see above). 2354 SafepointSynchronize::block(curJT); 2355 } 2356 2357 if (thread->is_deopt_suspend()) { 2358 thread->clear_deopt_suspend(); 2359 RegisterMap map(thread, false); 2360 frame f = thread->last_frame(); 2361 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2362 f = f.sender(&map); 2363 } 2364 if (f.id() == thread->must_deopt_id()) { 2365 thread->clear_must_deopt_id(); 2366 f.deoptimize(thread); 2367 } else { 2368 fatal("missed deoptimization!"); 2369 } 2370 } 2371 } 2372 2373 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2374 // progress or when _suspend_flags is non-zero. 2375 // Current thread needs to self-suspend if there is a suspend request and/or 2376 // block if a safepoint is in progress. 2377 // Also check for pending async exception (not including unsafe access error). 2378 // Note only the native==>VM/Java barriers can call this function and when 2379 // thread state is _thread_in_native_trans. 2380 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2381 check_safepoint_and_suspend_for_native_trans(thread); 2382 2383 if (thread->has_async_exception()) { 2384 // We are in _thread_in_native_trans state, don't handle unsafe 2385 // access error since that may block. 2386 thread->check_and_handle_async_exceptions(false); 2387 } 2388 } 2389 2390 // This is a variant of the normal 2391 // check_special_condition_for_native_trans with slightly different 2392 // semantics for use by critical native wrappers. It does all the 2393 // normal checks but also performs the transition back into 2394 // thread_in_Java state. This is required so that critical natives 2395 // can potentially block and perform a GC if they are the last thread 2396 // exiting the GCLocker. 2397 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2398 check_special_condition_for_native_trans(thread); 2399 2400 // Finish the transition 2401 thread->set_thread_state(_thread_in_Java); 2402 2403 if (thread->do_critical_native_unlock()) { 2404 ThreadInVMfromJavaNoAsyncException tiv(thread); 2405 GCLocker::unlock_critical(thread); 2406 thread->clear_critical_native_unlock(); 2407 } 2408 } 2409 2410 // We need to guarantee the Threads_lock here, since resumes are not 2411 // allowed during safepoint synchronization 2412 // Can only resume from an external suspension 2413 void JavaThread::java_resume() { 2414 assert_locked_or_safepoint(Threads_lock); 2415 2416 // Sanity check: thread is gone, has started exiting or the thread 2417 // was not externally suspended. 2418 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2419 return; 2420 } 2421 2422 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2423 2424 clear_external_suspend(); 2425 2426 if (is_ext_suspended()) { 2427 clear_ext_suspended(); 2428 SR_lock()->notify_all(); 2429 } 2430 } 2431 2432 size_t JavaThread::_stack_red_zone_size = 0; 2433 size_t JavaThread::_stack_yellow_zone_size = 0; 2434 size_t JavaThread::_stack_reserved_zone_size = 0; 2435 size_t JavaThread::_stack_shadow_zone_size = 0; 2436 2437 void JavaThread::create_stack_guard_pages() { 2438 if (!os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) { return; } 2439 address low_addr = stack_end(); 2440 size_t len = stack_guard_zone_size(); 2441 2442 int must_commit = os::must_commit_stack_guard_pages(); 2443 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2444 2445 if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) { 2446 log_warning(os, thread)("Attempt to allocate stack guard pages failed."); 2447 return; 2448 } 2449 2450 if (os::guard_memory((char *) low_addr, len)) { 2451 _stack_guard_state = stack_guard_enabled; 2452 } else { 2453 log_warning(os, thread)("Attempt to protect stack guard pages failed (" 2454 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2455 if (os::uncommit_memory((char *) low_addr, len)) { 2456 log_warning(os, thread)("Attempt to deallocate stack guard pages failed."); 2457 } 2458 return; 2459 } 2460 2461 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: " 2462 PTR_FORMAT "-" PTR_FORMAT ".", 2463 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2464 } 2465 2466 void JavaThread::remove_stack_guard_pages() { 2467 assert(Thread::current() == this, "from different thread"); 2468 if (_stack_guard_state == stack_guard_unused) return; 2469 address low_addr = stack_end(); 2470 size_t len = stack_guard_zone_size(); 2471 2472 if (os::must_commit_stack_guard_pages()) { 2473 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2474 _stack_guard_state = stack_guard_unused; 2475 } else { 2476 log_warning(os, thread)("Attempt to deallocate stack guard pages failed (" 2477 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2478 return; 2479 } 2480 } else { 2481 if (_stack_guard_state == stack_guard_unused) return; 2482 if (os::unguard_memory((char *) low_addr, len)) { 2483 _stack_guard_state = stack_guard_unused; 2484 } else { 2485 log_warning(os, thread)("Attempt to unprotect stack guard pages failed (" 2486 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2487 return; 2488 } 2489 } 2490 2491 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: " 2492 PTR_FORMAT "-" PTR_FORMAT ".", 2493 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2494 } 2495 2496 void JavaThread::enable_stack_reserved_zone() { 2497 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2498 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2499 2500 // The base notation is from the stack's point of view, growing downward. 2501 // We need to adjust it to work correctly with guard_memory() 2502 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2503 2504 guarantee(base < stack_base(),"Error calculating stack reserved zone"); 2505 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone"); 2506 2507 if (os::guard_memory((char *) base, stack_reserved_zone_size())) { 2508 _stack_guard_state = stack_guard_enabled; 2509 } else { 2510 warning("Attempt to guard stack reserved zone failed."); 2511 } 2512 enable_register_stack_guard(); 2513 } 2514 2515 void JavaThread::disable_stack_reserved_zone() { 2516 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2517 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled"); 2518 2519 // Simply return if called for a thread that does not use guard pages. 2520 if (_stack_guard_state == stack_guard_unused) return; 2521 2522 // The base notation is from the stack's point of view, growing downward. 2523 // We need to adjust it to work correctly with guard_memory() 2524 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2525 2526 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) { 2527 _stack_guard_state = stack_guard_reserved_disabled; 2528 } else { 2529 warning("Attempt to unguard stack reserved zone failed."); 2530 } 2531 disable_register_stack_guard(); 2532 } 2533 2534 void JavaThread::enable_stack_yellow_reserved_zone() { 2535 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2536 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2537 2538 // The base notation is from the stacks point of view, growing downward. 2539 // We need to adjust it to work correctly with guard_memory() 2540 address base = stack_red_zone_base(); 2541 2542 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2543 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2544 2545 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) { 2546 _stack_guard_state = stack_guard_enabled; 2547 } else { 2548 warning("Attempt to guard stack yellow zone failed."); 2549 } 2550 enable_register_stack_guard(); 2551 } 2552 2553 void JavaThread::disable_stack_yellow_reserved_zone() { 2554 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2555 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled"); 2556 2557 // Simply return if called for a thread that does not use guard pages. 2558 if (_stack_guard_state == stack_guard_unused) return; 2559 2560 // The base notation is from the stacks point of view, growing downward. 2561 // We need to adjust it to work correctly with guard_memory() 2562 address base = stack_red_zone_base(); 2563 2564 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) { 2565 _stack_guard_state = stack_guard_yellow_reserved_disabled; 2566 } else { 2567 warning("Attempt to unguard stack yellow zone failed."); 2568 } 2569 disable_register_stack_guard(); 2570 } 2571 2572 void JavaThread::enable_stack_red_zone() { 2573 // The base notation is from the stacks point of view, growing downward. 2574 // We need to adjust it to work correctly with guard_memory() 2575 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2576 address base = stack_red_zone_base() - stack_red_zone_size(); 2577 2578 guarantee(base < stack_base(), "Error calculating stack red zone"); 2579 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2580 2581 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2582 warning("Attempt to guard stack red zone failed."); 2583 } 2584 } 2585 2586 void JavaThread::disable_stack_red_zone() { 2587 // The base notation is from the stacks point of view, growing downward. 2588 // We need to adjust it to work correctly with guard_memory() 2589 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2590 address base = stack_red_zone_base() - stack_red_zone_size(); 2591 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2592 warning("Attempt to unguard stack red zone failed."); 2593 } 2594 } 2595 2596 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2597 // ignore is there is no stack 2598 if (!has_last_Java_frame()) return; 2599 // traverse the stack frames. Starts from top frame. 2600 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2601 frame* fr = fst.current(); 2602 f(fr, fst.register_map()); 2603 } 2604 } 2605 2606 2607 #ifndef PRODUCT 2608 // Deoptimization 2609 // Function for testing deoptimization 2610 void JavaThread::deoptimize() { 2611 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2612 StackFrameStream fst(this, UseBiasedLocking); 2613 bool deopt = false; // Dump stack only if a deopt actually happens. 2614 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2615 // Iterate over all frames in the thread and deoptimize 2616 for (; !fst.is_done(); fst.next()) { 2617 if (fst.current()->can_be_deoptimized()) { 2618 2619 if (only_at) { 2620 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2621 // consists of comma or carriage return separated numbers so 2622 // search for the current bci in that string. 2623 address pc = fst.current()->pc(); 2624 nmethod* nm = (nmethod*) fst.current()->cb(); 2625 ScopeDesc* sd = nm->scope_desc_at(pc); 2626 char buffer[8]; 2627 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2628 size_t len = strlen(buffer); 2629 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2630 while (found != NULL) { 2631 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2632 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2633 // Check that the bci found is bracketed by terminators. 2634 break; 2635 } 2636 found = strstr(found + 1, buffer); 2637 } 2638 if (!found) { 2639 continue; 2640 } 2641 } 2642 2643 if (DebugDeoptimization && !deopt) { 2644 deopt = true; // One-time only print before deopt 2645 tty->print_cr("[BEFORE Deoptimization]"); 2646 trace_frames(); 2647 trace_stack(); 2648 } 2649 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2650 } 2651 } 2652 2653 if (DebugDeoptimization && deopt) { 2654 tty->print_cr("[AFTER Deoptimization]"); 2655 trace_frames(); 2656 } 2657 } 2658 2659 2660 // Make zombies 2661 void JavaThread::make_zombies() { 2662 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2663 if (fst.current()->can_be_deoptimized()) { 2664 // it is a Java nmethod 2665 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2666 nm->make_not_entrant(); 2667 } 2668 } 2669 } 2670 #endif // PRODUCT 2671 2672 2673 void JavaThread::deoptimized_wrt_marked_nmethods() { 2674 if (!has_last_Java_frame()) return; 2675 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2676 StackFrameStream fst(this, UseBiasedLocking); 2677 for (; !fst.is_done(); fst.next()) { 2678 if (fst.current()->should_be_deoptimized()) { 2679 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2680 } 2681 } 2682 } 2683 2684 2685 // If the caller is a NamedThread, then remember, in the current scope, 2686 // the given JavaThread in its _processed_thread field. 2687 class RememberProcessedThread: public StackObj { 2688 NamedThread* _cur_thr; 2689 public: 2690 RememberProcessedThread(JavaThread* jthr) { 2691 Thread* thread = Thread::current(); 2692 if (thread->is_Named_thread()) { 2693 _cur_thr = (NamedThread *)thread; 2694 _cur_thr->set_processed_thread(jthr); 2695 } else { 2696 _cur_thr = NULL; 2697 } 2698 } 2699 2700 ~RememberProcessedThread() { 2701 if (_cur_thr) { 2702 _cur_thr->set_processed_thread(NULL); 2703 } 2704 } 2705 }; 2706 2707 void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 2708 // Verify that the deferred card marks have been flushed. 2709 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2710 2711 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2712 // since there may be more than one thread using each ThreadProfiler. 2713 2714 // Traverse the GCHandles 2715 Thread::oops_do(f, cf); 2716 2717 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);) 2718 2719 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2720 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2721 2722 if (has_last_Java_frame()) { 2723 // Record JavaThread to GC thread 2724 RememberProcessedThread rpt(this); 2725 2726 // Traverse the privileged stack 2727 if (_privileged_stack_top != NULL) { 2728 _privileged_stack_top->oops_do(f); 2729 } 2730 2731 // traverse the registered growable array 2732 if (_array_for_gc != NULL) { 2733 for (int index = 0; index < _array_for_gc->length(); index++) { 2734 f->do_oop(_array_for_gc->adr_at(index)); 2735 } 2736 } 2737 2738 // Traverse the monitor chunks 2739 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2740 chunk->oops_do(f); 2741 } 2742 2743 // Traverse the execution stack 2744 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2745 fst.current()->oops_do(f, cf, fst.register_map()); 2746 } 2747 } 2748 2749 // callee_target is never live across a gc point so NULL it here should 2750 // it still contain a methdOop. 2751 2752 set_callee_target(NULL); 2753 2754 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2755 // If we have deferred set_locals there might be oops waiting to be 2756 // written 2757 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2758 if (list != NULL) { 2759 for (int i = 0; i < list->length(); i++) { 2760 list->at(i)->oops_do(f); 2761 } 2762 } 2763 2764 // Traverse instance variables at the end since the GC may be moving things 2765 // around using this function 2766 f->do_oop((oop*) &_threadObj); 2767 f->do_oop((oop*) &_vm_result); 2768 f->do_oop((oop*) &_exception_oop); 2769 f->do_oop((oop*) &_pending_async_exception); 2770 2771 if (jvmti_thread_state() != NULL) { 2772 jvmti_thread_state()->oops_do(f); 2773 } 2774 } 2775 2776 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2777 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2778 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2779 2780 if (has_last_Java_frame()) { 2781 // Traverse the execution stack 2782 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2783 fst.current()->nmethods_do(cf); 2784 } 2785 } 2786 } 2787 2788 void JavaThread::metadata_do(void f(Metadata*)) { 2789 if (has_last_Java_frame()) { 2790 // Traverse the execution stack to call f() on the methods in the stack 2791 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2792 fst.current()->metadata_do(f); 2793 } 2794 } else if (is_Compiler_thread()) { 2795 // need to walk ciMetadata in current compile tasks to keep alive. 2796 CompilerThread* ct = (CompilerThread*)this; 2797 if (ct->env() != NULL) { 2798 ct->env()->metadata_do(f); 2799 } 2800 if (ct->task() != NULL) { 2801 ct->task()->metadata_do(f); 2802 } 2803 } 2804 } 2805 2806 // Printing 2807 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2808 switch (_thread_state) { 2809 case _thread_uninitialized: return "_thread_uninitialized"; 2810 case _thread_new: return "_thread_new"; 2811 case _thread_new_trans: return "_thread_new_trans"; 2812 case _thread_in_native: return "_thread_in_native"; 2813 case _thread_in_native_trans: return "_thread_in_native_trans"; 2814 case _thread_in_vm: return "_thread_in_vm"; 2815 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2816 case _thread_in_Java: return "_thread_in_Java"; 2817 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2818 case _thread_blocked: return "_thread_blocked"; 2819 case _thread_blocked_trans: return "_thread_blocked_trans"; 2820 default: return "unknown thread state"; 2821 } 2822 } 2823 2824 #ifndef PRODUCT 2825 void JavaThread::print_thread_state_on(outputStream *st) const { 2826 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2827 }; 2828 void JavaThread::print_thread_state() const { 2829 print_thread_state_on(tty); 2830 } 2831 #endif // PRODUCT 2832 2833 // Called by Threads::print() for VM_PrintThreads operation 2834 void JavaThread::print_on(outputStream *st) const { 2835 st->print_raw("\""); 2836 st->print_raw(get_thread_name()); 2837 st->print_raw("\" "); 2838 oop thread_oop = threadObj(); 2839 if (thread_oop != NULL) { 2840 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2841 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2842 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2843 } 2844 Thread::print_on(st); 2845 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2846 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2847 if (thread_oop != NULL) { 2848 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2849 } 2850 #ifndef PRODUCT 2851 print_thread_state_on(st); 2852 _safepoint_state->print_on(st); 2853 #endif // PRODUCT 2854 if (is_Compiler_thread()) { 2855 CompilerThread* ct = (CompilerThread*)this; 2856 if (ct->task() != NULL) { 2857 st->print(" Compiling: "); 2858 ct->task()->print(st, NULL, true, false); 2859 } else { 2860 st->print(" No compile task"); 2861 } 2862 st->cr(); 2863 } 2864 } 2865 2866 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const { 2867 st->print("%s", get_thread_name_string(buf, buflen)); 2868 } 2869 2870 // Called by fatal error handler. The difference between this and 2871 // JavaThread::print() is that we can't grab lock or allocate memory. 2872 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2873 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2874 oop thread_obj = threadObj(); 2875 if (thread_obj != NULL) { 2876 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2877 } 2878 st->print(" ["); 2879 st->print("%s", _get_thread_state_name(_thread_state)); 2880 if (osthread()) { 2881 st->print(", id=%d", osthread()->thread_id()); 2882 } 2883 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2884 p2i(stack_end()), p2i(stack_base())); 2885 st->print("]"); 2886 return; 2887 } 2888 2889 // Verification 2890 2891 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2892 2893 void JavaThread::verify() { 2894 // Verify oops in the thread. 2895 oops_do(&VerifyOopClosure::verify_oop, NULL); 2896 2897 // Verify the stack frames. 2898 frames_do(frame_verify); 2899 } 2900 2901 // CR 6300358 (sub-CR 2137150) 2902 // Most callers of this method assume that it can't return NULL but a 2903 // thread may not have a name whilst it is in the process of attaching to 2904 // the VM - see CR 6412693, and there are places where a JavaThread can be 2905 // seen prior to having it's threadObj set (eg JNI attaching threads and 2906 // if vm exit occurs during initialization). These cases can all be accounted 2907 // for such that this method never returns NULL. 2908 const char* JavaThread::get_thread_name() const { 2909 #ifdef ASSERT 2910 // early safepoints can hit while current thread does not yet have TLS 2911 if (!SafepointSynchronize::is_at_safepoint()) { 2912 Thread *cur = Thread::current(); 2913 if (!(cur->is_Java_thread() && cur == this)) { 2914 // Current JavaThreads are allowed to get their own name without 2915 // the Threads_lock. 2916 assert_locked_or_safepoint(Threads_lock); 2917 } 2918 } 2919 #endif // ASSERT 2920 return get_thread_name_string(); 2921 } 2922 2923 // Returns a non-NULL representation of this thread's name, or a suitable 2924 // descriptive string if there is no set name 2925 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2926 const char* name_str; 2927 oop thread_obj = threadObj(); 2928 if (thread_obj != NULL) { 2929 oop name = java_lang_Thread::name(thread_obj); 2930 if (name != NULL) { 2931 if (buf == NULL) { 2932 name_str = java_lang_String::as_utf8_string(name); 2933 } else { 2934 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 2935 } 2936 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2937 name_str = "<no-name - thread is attaching>"; 2938 } else { 2939 name_str = Thread::name(); 2940 } 2941 } else { 2942 name_str = Thread::name(); 2943 } 2944 assert(name_str != NULL, "unexpected NULL thread name"); 2945 return name_str; 2946 } 2947 2948 2949 const char* JavaThread::get_threadgroup_name() const { 2950 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2951 oop thread_obj = threadObj(); 2952 if (thread_obj != NULL) { 2953 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2954 if (thread_group != NULL) { 2955 // ThreadGroup.name can be null 2956 return java_lang_ThreadGroup::name(thread_group); 2957 } 2958 } 2959 return NULL; 2960 } 2961 2962 const char* JavaThread::get_parent_name() const { 2963 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2964 oop thread_obj = threadObj(); 2965 if (thread_obj != NULL) { 2966 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2967 if (thread_group != NULL) { 2968 oop parent = java_lang_ThreadGroup::parent(thread_group); 2969 if (parent != NULL) { 2970 // ThreadGroup.name can be null 2971 return java_lang_ThreadGroup::name(parent); 2972 } 2973 } 2974 } 2975 return NULL; 2976 } 2977 2978 ThreadPriority JavaThread::java_priority() const { 2979 oop thr_oop = threadObj(); 2980 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2981 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2982 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2983 return priority; 2984 } 2985 2986 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2987 2988 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2989 // Link Java Thread object <-> C++ Thread 2990 2991 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2992 // and put it into a new Handle. The Handle "thread_oop" can then 2993 // be used to pass the C++ thread object to other methods. 2994 2995 // Set the Java level thread object (jthread) field of the 2996 // new thread (a JavaThread *) to C++ thread object using the 2997 // "thread_oop" handle. 2998 2999 // Set the thread field (a JavaThread *) of the 3000 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3001 3002 Handle thread_oop(Thread::current(), 3003 JNIHandles::resolve_non_null(jni_thread)); 3004 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3005 "must be initialized"); 3006 set_threadObj(thread_oop()); 3007 java_lang_Thread::set_thread(thread_oop(), this); 3008 3009 if (prio == NoPriority) { 3010 prio = java_lang_Thread::priority(thread_oop()); 3011 assert(prio != NoPriority, "A valid priority should be present"); 3012 } 3013 3014 // Push the Java priority down to the native thread; needs Threads_lock 3015 Thread::set_priority(this, prio); 3016 3017 prepare_ext(); 3018 3019 // Add the new thread to the Threads list and set it in motion. 3020 // We must have threads lock in order to call Threads::add. 3021 // It is crucial that we do not block before the thread is 3022 // added to the Threads list for if a GC happens, then the java_thread oop 3023 // will not be visited by GC. 3024 Threads::add(this); 3025 } 3026 3027 oop JavaThread::current_park_blocker() { 3028 // Support for JSR-166 locks 3029 oop thread_oop = threadObj(); 3030 if (thread_oop != NULL && 3031 JDK_Version::current().supports_thread_park_blocker()) { 3032 return java_lang_Thread::park_blocker(thread_oop); 3033 } 3034 return NULL; 3035 } 3036 3037 3038 void JavaThread::print_stack_on(outputStream* st) { 3039 if (!has_last_Java_frame()) return; 3040 ResourceMark rm; 3041 HandleMark hm; 3042 3043 RegisterMap reg_map(this); 3044 vframe* start_vf = last_java_vframe(®_map); 3045 int count = 0; 3046 for (vframe* f = start_vf; f; f = f->sender()) { 3047 if (f->is_java_frame()) { 3048 javaVFrame* jvf = javaVFrame::cast(f); 3049 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3050 3051 // Print out lock information 3052 if (JavaMonitorsInStackTrace) { 3053 jvf->print_lock_info_on(st, count); 3054 } 3055 } else { 3056 // Ignore non-Java frames 3057 } 3058 3059 // Bail-out case for too deep stacks 3060 count++; 3061 if (MaxJavaStackTraceDepth == count) return; 3062 } 3063 } 3064 3065 3066 // JVMTI PopFrame support 3067 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3068 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3069 if (in_bytes(size_in_bytes) != 0) { 3070 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3071 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3072 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3073 } 3074 } 3075 3076 void* JavaThread::popframe_preserved_args() { 3077 return _popframe_preserved_args; 3078 } 3079 3080 ByteSize JavaThread::popframe_preserved_args_size() { 3081 return in_ByteSize(_popframe_preserved_args_size); 3082 } 3083 3084 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3085 int sz = in_bytes(popframe_preserved_args_size()); 3086 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3087 return in_WordSize(sz / wordSize); 3088 } 3089 3090 void JavaThread::popframe_free_preserved_args() { 3091 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3092 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3093 _popframe_preserved_args = NULL; 3094 _popframe_preserved_args_size = 0; 3095 } 3096 3097 #ifndef PRODUCT 3098 3099 void JavaThread::trace_frames() { 3100 tty->print_cr("[Describe stack]"); 3101 int frame_no = 1; 3102 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3103 tty->print(" %d. ", frame_no++); 3104 fst.current()->print_value_on(tty, this); 3105 tty->cr(); 3106 } 3107 } 3108 3109 class PrintAndVerifyOopClosure: public OopClosure { 3110 protected: 3111 template <class T> inline void do_oop_work(T* p) { 3112 oop obj = oopDesc::load_decode_heap_oop(p); 3113 if (obj == NULL) return; 3114 tty->print(INTPTR_FORMAT ": ", p2i(p)); 3115 if (obj->is_oop_or_null()) { 3116 if (obj->is_objArray()) { 3117 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); 3118 } else { 3119 obj->print(); 3120 } 3121 } else { 3122 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); 3123 } 3124 tty->cr(); 3125 } 3126 public: 3127 virtual void do_oop(oop* p) { do_oop_work(p); } 3128 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3129 }; 3130 3131 3132 static void oops_print(frame* f, const RegisterMap *map) { 3133 PrintAndVerifyOopClosure print; 3134 f->print_value(); 3135 f->oops_do(&print, NULL, (RegisterMap*)map); 3136 } 3137 3138 // Print our all the locations that contain oops and whether they are 3139 // valid or not. This useful when trying to find the oldest frame 3140 // where an oop has gone bad since the frame walk is from youngest to 3141 // oldest. 3142 void JavaThread::trace_oops() { 3143 tty->print_cr("[Trace oops]"); 3144 frames_do(oops_print); 3145 } 3146 3147 3148 #ifdef ASSERT 3149 // Print or validate the layout of stack frames 3150 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3151 ResourceMark rm; 3152 PRESERVE_EXCEPTION_MARK; 3153 FrameValues values; 3154 int frame_no = 0; 3155 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3156 fst.current()->describe(values, ++frame_no); 3157 if (depth == frame_no) break; 3158 } 3159 if (validate_only) { 3160 values.validate(); 3161 } else { 3162 tty->print_cr("[Describe stack layout]"); 3163 values.print(this); 3164 } 3165 } 3166 #endif 3167 3168 void JavaThread::trace_stack_from(vframe* start_vf) { 3169 ResourceMark rm; 3170 int vframe_no = 1; 3171 for (vframe* f = start_vf; f; f = f->sender()) { 3172 if (f->is_java_frame()) { 3173 javaVFrame::cast(f)->print_activation(vframe_no++); 3174 } else { 3175 f->print(); 3176 } 3177 if (vframe_no > StackPrintLimit) { 3178 tty->print_cr("...<more frames>..."); 3179 return; 3180 } 3181 } 3182 } 3183 3184 3185 void JavaThread::trace_stack() { 3186 if (!has_last_Java_frame()) return; 3187 ResourceMark rm; 3188 HandleMark hm; 3189 RegisterMap reg_map(this); 3190 trace_stack_from(last_java_vframe(®_map)); 3191 } 3192 3193 3194 #endif // PRODUCT 3195 3196 3197 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3198 assert(reg_map != NULL, "a map must be given"); 3199 frame f = last_frame(); 3200 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3201 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3202 } 3203 return NULL; 3204 } 3205 3206 3207 Klass* JavaThread::security_get_caller_class(int depth) { 3208 vframeStream vfst(this); 3209 vfst.security_get_caller_frame(depth); 3210 if (!vfst.at_end()) { 3211 return vfst.method()->method_holder(); 3212 } 3213 return NULL; 3214 } 3215 3216 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3217 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3218 CompileBroker::compiler_thread_loop(); 3219 } 3220 3221 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3222 NMethodSweeper::sweeper_loop(); 3223 } 3224 3225 // Create a CompilerThread 3226 CompilerThread::CompilerThread(CompileQueue* queue, 3227 CompilerCounters* counters) 3228 : JavaThread(&compiler_thread_entry) { 3229 _env = NULL; 3230 _log = NULL; 3231 _task = NULL; 3232 _queue = queue; 3233 _counters = counters; 3234 _buffer_blob = NULL; 3235 _compiler = NULL; 3236 3237 #ifndef PRODUCT 3238 _ideal_graph_printer = NULL; 3239 #endif 3240 } 3241 3242 bool CompilerThread::can_call_java() const { 3243 return _compiler != NULL && _compiler->is_jvmci(); 3244 } 3245 3246 // Create sweeper thread 3247 CodeCacheSweeperThread::CodeCacheSweeperThread() 3248 : JavaThread(&sweeper_thread_entry) { 3249 _scanned_compiled_method = NULL; 3250 } 3251 3252 void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 3253 JavaThread::oops_do(f, cf); 3254 if (_scanned_compiled_method != NULL && cf != NULL) { 3255 // Safepoints can occur when the sweeper is scanning an nmethod so 3256 // process it here to make sure it isn't unloaded in the middle of 3257 // a scan. 3258 cf->do_code_blob(_scanned_compiled_method); 3259 } 3260 } 3261 3262 void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) { 3263 JavaThread::nmethods_do(cf); 3264 if (_scanned_compiled_method != NULL && cf != NULL) { 3265 // Safepoints can occur when the sweeper is scanning an nmethod so 3266 // process it here to make sure it isn't unloaded in the middle of 3267 // a scan. 3268 cf->do_code_blob(_scanned_compiled_method); 3269 } 3270 } 3271 3272 3273 // ======= Threads ======== 3274 3275 // The Threads class links together all active threads, and provides 3276 // operations over all threads. It is protected by its own Mutex 3277 // lock, which is also used in other contexts to protect thread 3278 // operations from having the thread being operated on from exiting 3279 // and going away unexpectedly (e.g., safepoint synchronization) 3280 3281 JavaThread* Threads::_thread_list = NULL; 3282 int Threads::_number_of_threads = 0; 3283 int Threads::_number_of_non_daemon_threads = 0; 3284 int Threads::_return_code = 0; 3285 int Threads::_thread_claim_parity = 0; 3286 size_t JavaThread::_stack_size_at_create = 0; 3287 #ifdef ASSERT 3288 bool Threads::_vm_complete = false; 3289 #endif 3290 3291 // All JavaThreads 3292 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3293 3294 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3295 void Threads::threads_do(ThreadClosure* tc) { 3296 assert_locked_or_safepoint(Threads_lock); 3297 // ALL_JAVA_THREADS iterates through all JavaThreads 3298 ALL_JAVA_THREADS(p) { 3299 tc->do_thread(p); 3300 } 3301 // Someday we could have a table or list of all non-JavaThreads. 3302 // For now, just manually iterate through them. 3303 tc->do_thread(VMThread::vm_thread()); 3304 Universe::heap()->gc_threads_do(tc); 3305 WatcherThread *wt = WatcherThread::watcher_thread(); 3306 // Strictly speaking, the following NULL check isn't sufficient to make sure 3307 // the data for WatcherThread is still valid upon being examined. However, 3308 // considering that WatchThread terminates when the VM is on the way to 3309 // exit at safepoint, the chance of the above is extremely small. The right 3310 // way to prevent termination of WatcherThread would be to acquire 3311 // Terminator_lock, but we can't do that without violating the lock rank 3312 // checking in some cases. 3313 if (wt != NULL) { 3314 tc->do_thread(wt); 3315 } 3316 3317 // If CompilerThreads ever become non-JavaThreads, add them here 3318 } 3319 3320 // The system initialization in the library has three phases. 3321 // 3322 // Phase 1: java.lang.System class initialization 3323 // java.lang.System is a primordial class loaded and initialized 3324 // by the VM early during startup. java.lang.System.<clinit> 3325 // only does registerNatives and keeps the rest of the class 3326 // initialization work later until thread initialization completes. 3327 // 3328 // System.initPhase1 initializes the system properties, the static 3329 // fields in, out, and err. Set up java signal handlers, OS-specific 3330 // system settings, and thread group of the main thread. 3331 static void call_initPhase1(TRAPS) { 3332 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3333 JavaValue result(T_VOID); 3334 JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(), 3335 vmSymbols::void_method_signature(), CHECK); 3336 } 3337 3338 // Phase 2. Module system initialization 3339 // This will initialize the module system. Only java.base classes 3340 // can be loaded until phase 2 completes. 3341 // 3342 // Call System.initPhase2 after the compiler initialization and jsr292 3343 // classes get initialized because module initialization runs a lot of java 3344 // code, that for performance reasons, should be compiled. Also, this will 3345 // enable the startup code to use lambda and other language features in this 3346 // phase and onward. 3347 // 3348 // After phase 2, The VM will begin search classes from -Xbootclasspath/a. 3349 static void call_initPhase2(TRAPS) { 3350 TraceTime timer("Phase2 initialization", TRACETIME_LOG(Info, modules, startuptime)); 3351 3352 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3353 3354 JavaValue result(T_INT); 3355 JavaCallArguments args; 3356 args.push_int(DisplayVMOutputToStderr); 3357 args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown 3358 JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(), 3359 vmSymbols::boolean_boolean_int_signature(), &args, CHECK); 3360 if (result.get_jint() != JNI_OK) { 3361 vm_exit_during_initialization(); // no message or exception 3362 } 3363 3364 universe_post_module_init(); 3365 } 3366 3367 // Phase 3. final setup - set security manager, system class loader and TCCL 3368 // 3369 // This will instantiate and set the security manager, set the system class 3370 // loader as well as the thread context class loader. The security manager 3371 // and system class loader may be a custom class loaded from -Xbootclasspath/a, 3372 // other modules or the application's classpath. 3373 static void call_initPhase3(TRAPS) { 3374 Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 3375 JavaValue result(T_VOID); 3376 JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(), 3377 vmSymbols::void_method_signature(), CHECK); 3378 } 3379 3380 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3381 TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime)); 3382 3383 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3384 create_vm_init_libraries(); 3385 } 3386 3387 initialize_class(vmSymbols::java_lang_String(), CHECK); 3388 3389 // Inject CompactStrings value after the static initializers for String ran. 3390 java_lang_String::set_compact_strings(CompactStrings); 3391 3392 // Initialize java_lang.System (needed before creating the thread) 3393 initialize_class(vmSymbols::java_lang_System(), CHECK); 3394 // The VM creates & returns objects of this class. Make sure it's initialized. 3395 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3396 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3397 Handle thread_group = create_initial_thread_group(CHECK); 3398 Universe::set_main_thread_group(thread_group()); 3399 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3400 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3401 main_thread->set_threadObj(thread_object); 3402 // Set thread status to running since main thread has 3403 // been started and running. 3404 java_lang_Thread::set_thread_status(thread_object, 3405 java_lang_Thread::RUNNABLE); 3406 3407 // The VM creates objects of this class. 3408 initialize_class(vmSymbols::java_lang_Module(), CHECK); 3409 3410 // The VM preresolves methods to these classes. Make sure that they get initialized 3411 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3412 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3413 3414 // Phase 1 of the system initialization in the library, java.lang.System class initialization 3415 call_initPhase1(CHECK); 3416 3417 // get the Java runtime name after java.lang.System is initialized 3418 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3419 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3420 3421 // an instance of OutOfMemory exception has been allocated earlier 3422 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3423 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3424 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3425 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3426 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3427 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3428 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3429 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3430 } 3431 3432 void Threads::initialize_jsr292_core_classes(TRAPS) { 3433 TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime)); 3434 3435 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3436 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3437 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3438 } 3439 3440 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3441 extern void JDK_Version_init(); 3442 3443 // Preinitialize version info. 3444 VM_Version::early_initialize(); 3445 3446 // Check version 3447 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3448 3449 // Initialize library-based TLS 3450 ThreadLocalStorage::init(); 3451 3452 // Initialize the output stream module 3453 ostream_init(); 3454 3455 // Process java launcher properties. 3456 Arguments::process_sun_java_launcher_properties(args); 3457 3458 // Initialize the os module 3459 os::init(); 3460 3461 // Record VM creation timing statistics 3462 TraceVmCreationTime create_vm_timer; 3463 create_vm_timer.start(); 3464 3465 // Initialize system properties. 3466 Arguments::init_system_properties(); 3467 3468 // So that JDK version can be used as a discriminator when parsing arguments 3469 JDK_Version_init(); 3470 3471 // Update/Initialize System properties after JDK version number is known 3472 Arguments::init_version_specific_system_properties(); 3473 3474 // Make sure to initialize log configuration *before* parsing arguments 3475 LogConfiguration::initialize(create_vm_timer.begin_time()); 3476 3477 // Parse arguments 3478 jint parse_result = Arguments::parse(args); 3479 if (parse_result != JNI_OK) return parse_result; 3480 3481 os::init_before_ergo(); 3482 3483 jint ergo_result = Arguments::apply_ergo(); 3484 if (ergo_result != JNI_OK) return ergo_result; 3485 3486 // Final check of all ranges after ergonomics which may change values. 3487 if (!CommandLineFlagRangeList::check_ranges()) { 3488 return JNI_EINVAL; 3489 } 3490 3491 // Final check of all 'AfterErgo' constraints after ergonomics which may change values. 3492 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo); 3493 if (!constraint_result) { 3494 return JNI_EINVAL; 3495 } 3496 3497 CommandLineFlagWriteableList::mark_startup(); 3498 3499 if (PauseAtStartup) { 3500 os::pause(); 3501 } 3502 3503 HOTSPOT_VM_INIT_BEGIN(); 3504 3505 // Timing (must come after argument parsing) 3506 TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime)); 3507 3508 // Initialize the os module after parsing the args 3509 jint os_init_2_result = os::init_2(); 3510 if (os_init_2_result != JNI_OK) return os_init_2_result; 3511 3512 jint adjust_after_os_result = Arguments::adjust_after_os(); 3513 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3514 3515 // Initialize output stream logging 3516 ostream_init_log(); 3517 3518 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3519 // Must be before create_vm_init_agents() 3520 if (Arguments::init_libraries_at_startup()) { 3521 convert_vm_init_libraries_to_agents(); 3522 } 3523 3524 // Launch -agentlib/-agentpath and converted -Xrun agents 3525 if (Arguments::init_agents_at_startup()) { 3526 create_vm_init_agents(); 3527 } 3528 3529 // Initialize Threads state 3530 _thread_list = NULL; 3531 _number_of_threads = 0; 3532 _number_of_non_daemon_threads = 0; 3533 3534 // Initialize global data structures and create system classes in heap 3535 vm_init_globals(); 3536 3537 #if INCLUDE_JVMCI 3538 if (JVMCICounterSize > 0) { 3539 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 3540 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize); 3541 } else { 3542 JavaThread::_jvmci_old_thread_counters = NULL; 3543 } 3544 #endif // INCLUDE_JVMCI 3545 3546 // Attach the main thread to this os thread 3547 JavaThread* main_thread = new JavaThread(); 3548 main_thread->set_thread_state(_thread_in_vm); 3549 main_thread->initialize_thread_current(); 3550 // must do this before set_active_handles 3551 main_thread->record_stack_base_and_size(); 3552 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3553 3554 if (!main_thread->set_as_starting_thread()) { 3555 vm_shutdown_during_initialization( 3556 "Failed necessary internal allocation. Out of swap space"); 3557 delete main_thread; 3558 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3559 return JNI_ENOMEM; 3560 } 3561 3562 // Enable guard page *after* os::create_main_thread(), otherwise it would 3563 // crash Linux VM, see notes in os_linux.cpp. 3564 main_thread->create_stack_guard_pages(); 3565 3566 // Initialize Java-Level synchronization subsystem 3567 ObjectMonitor::Initialize(); 3568 3569 // Initialize global modules 3570 jint status = init_globals(); 3571 if (status != JNI_OK) { 3572 delete main_thread; 3573 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3574 return status; 3575 } 3576 3577 if (TRACE_INITIALIZE() != JNI_OK) { 3578 vm_exit_during_initialization("Failed to initialize tracing backend"); 3579 } 3580 3581 // Should be done after the heap is fully created 3582 main_thread->cache_global_variables(); 3583 3584 HandleMark hm; 3585 3586 { MutexLocker mu(Threads_lock); 3587 Threads::add(main_thread); 3588 } 3589 3590 // Any JVMTI raw monitors entered in onload will transition into 3591 // real raw monitor. VM is setup enough here for raw monitor enter. 3592 JvmtiExport::transition_pending_onload_raw_monitors(); 3593 3594 // Create the VMThread 3595 { TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime)); 3596 3597 VMThread::create(); 3598 Thread* vmthread = VMThread::vm_thread(); 3599 3600 if (!os::create_thread(vmthread, os::vm_thread)) { 3601 vm_exit_during_initialization("Cannot create VM thread. " 3602 "Out of system resources."); 3603 } 3604 3605 // Wait for the VM thread to become ready, and VMThread::run to initialize 3606 // Monitors can have spurious returns, must always check another state flag 3607 { 3608 MutexLocker ml(Notify_lock); 3609 os::start_thread(vmthread); 3610 while (vmthread->active_handles() == NULL) { 3611 Notify_lock->wait(); 3612 } 3613 } 3614 } 3615 3616 assert(Universe::is_fully_initialized(), "not initialized"); 3617 if (VerifyDuringStartup) { 3618 // Make sure we're starting with a clean slate. 3619 VM_Verify verify_op; 3620 VMThread::execute(&verify_op); 3621 } 3622 3623 Thread* THREAD = Thread::current(); 3624 3625 // At this point, the Universe is initialized, but we have not executed 3626 // any byte code. Now is a good time (the only time) to dump out the 3627 // internal state of the JVM for sharing. 3628 if (DumpSharedSpaces) { 3629 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3630 ShouldNotReachHere(); 3631 } 3632 3633 // Always call even when there are not JVMTI environments yet, since environments 3634 // may be attached late and JVMTI must track phases of VM execution 3635 JvmtiExport::enter_early_start_phase(); 3636 3637 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3638 JvmtiExport::post_early_vm_start(); 3639 3640 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3641 3642 // We need this for ClassDataSharing - the initial vm.info property is set 3643 // with the default value of CDS "sharing" which may be reset through 3644 // command line options. 3645 reset_vm_info_property(CHECK_JNI_ERR); 3646 3647 quicken_jni_functions(); 3648 3649 // No more stub generation allowed after that point. 3650 StubCodeDesc::freeze(); 3651 3652 // Set flag that basic initialization has completed. Used by exceptions and various 3653 // debug stuff, that does not work until all basic classes have been initialized. 3654 set_init_completed(); 3655 3656 LogConfiguration::post_initialize(); 3657 Metaspace::post_initialize(); 3658 3659 HOTSPOT_VM_INIT_END(); 3660 3661 // record VM initialization completion time 3662 #if INCLUDE_MANAGEMENT 3663 Management::record_vm_init_completed(); 3664 #endif // INCLUDE_MANAGEMENT 3665 3666 // Signal Dispatcher needs to be started before VMInit event is posted 3667 os::signal_init(CHECK_JNI_ERR); 3668 3669 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3670 if (!DisableAttachMechanism) { 3671 AttachListener::vm_start(); 3672 if (StartAttachListener || AttachListener::init_at_startup()) { 3673 AttachListener::init(); 3674 } 3675 } 3676 3677 // Launch -Xrun agents 3678 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3679 // back-end can launch with -Xdebug -Xrunjdwp. 3680 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3681 create_vm_init_libraries(); 3682 } 3683 3684 if (CleanChunkPoolAsync) { 3685 Chunk::start_chunk_pool_cleaner_task(); 3686 } 3687 3688 // initialize compiler(s) 3689 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI 3690 CompileBroker::compilation_init(CHECK_JNI_ERR); 3691 #endif 3692 3693 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3694 // It is done after compilers are initialized, because otherwise compilations of 3695 // signature polymorphic MH intrinsics can be missed 3696 // (see SystemDictionary::find_method_handle_intrinsic). 3697 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3698 3699 // This will initialize the module system. Only java.base classes can be 3700 // loaded until phase 2 completes 3701 call_initPhase2(CHECK_JNI_ERR); 3702 3703 // Always call even when there are not JVMTI environments yet, since environments 3704 // may be attached late and JVMTI must track phases of VM execution 3705 JvmtiExport::enter_start_phase(); 3706 3707 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3708 JvmtiExport::post_vm_start(); 3709 3710 // Final system initialization including security manager and system class loader 3711 call_initPhase3(CHECK_JNI_ERR); 3712 3713 // cache the system class loader 3714 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR)); 3715 3716 #if INCLUDE_JVMCI 3717 if (EnableJVMCI) { 3718 // Initialize JVMCI eagerly if JVMCIPrintProperties is enabled. 3719 // The JVMCI Java initialization code will read this flag and 3720 // do the printing if it's set. 3721 bool init = JVMCIPrintProperties; 3722 3723 if (!init) { 3724 // 8145270: Force initialization of JVMCI runtime otherwise requests for blocking 3725 // compilations via JVMCI will not actually block until JVMCI is initialized. 3726 init = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation); 3727 } 3728 3729 if (init) { 3730 JVMCIRuntime::force_initialization(CHECK_JNI_ERR); 3731 } 3732 } 3733 #endif 3734 3735 // Always call even when there are not JVMTI environments yet, since environments 3736 // may be attached late and JVMTI must track phases of VM execution 3737 JvmtiExport::enter_live_phase(); 3738 3739 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3740 JvmtiExport::post_vm_initialized(); 3741 3742 if (TRACE_START() != JNI_OK) { 3743 vm_exit_during_initialization("Failed to start tracing backend."); 3744 } 3745 3746 #if INCLUDE_MANAGEMENT 3747 Management::initialize(THREAD); 3748 3749 if (HAS_PENDING_EXCEPTION) { 3750 // management agent fails to start possibly due to 3751 // configuration problem and is responsible for printing 3752 // stack trace if appropriate. Simply exit VM. 3753 vm_exit(1); 3754 } 3755 #endif // INCLUDE_MANAGEMENT 3756 3757 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3758 if (MemProfiling) MemProfiler::engage(); 3759 StatSampler::engage(); 3760 if (CheckJNICalls) JniPeriodicChecker::engage(); 3761 3762 BiasedLocking::init(); 3763 3764 #if INCLUDE_RTM_OPT 3765 RTMLockingCounters::init(); 3766 #endif 3767 3768 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3769 call_postVMInitHook(THREAD); 3770 // The Java side of PostVMInitHook.run must deal with all 3771 // exceptions and provide means of diagnosis. 3772 if (HAS_PENDING_EXCEPTION) { 3773 CLEAR_PENDING_EXCEPTION; 3774 } 3775 } 3776 3777 { 3778 MutexLocker ml(PeriodicTask_lock); 3779 // Make sure the WatcherThread can be started by WatcherThread::start() 3780 // or by dynamic enrollment. 3781 WatcherThread::make_startable(); 3782 // Start up the WatcherThread if there are any periodic tasks 3783 // NOTE: All PeriodicTasks should be registered by now. If they 3784 // aren't, late joiners might appear to start slowly (we might 3785 // take a while to process their first tick). 3786 if (PeriodicTask::num_tasks() > 0) { 3787 WatcherThread::start(); 3788 } 3789 } 3790 3791 create_vm_timer.end(); 3792 #ifdef ASSERT 3793 _vm_complete = true; 3794 #endif 3795 return JNI_OK; 3796 } 3797 3798 // type for the Agent_OnLoad and JVM_OnLoad entry points 3799 extern "C" { 3800 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3801 } 3802 // Find a command line agent library and return its entry point for 3803 // -agentlib: -agentpath: -Xrun 3804 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3805 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 3806 const char *on_load_symbols[], 3807 size_t num_symbol_entries) { 3808 OnLoadEntry_t on_load_entry = NULL; 3809 void *library = NULL; 3810 3811 if (!agent->valid()) { 3812 char buffer[JVM_MAXPATHLEN]; 3813 char ebuf[1024] = ""; 3814 const char *name = agent->name(); 3815 const char *msg = "Could not find agent library "; 3816 3817 // First check to see if agent is statically linked into executable 3818 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3819 library = agent->os_lib(); 3820 } else if (agent->is_absolute_path()) { 3821 library = os::dll_load(name, ebuf, sizeof ebuf); 3822 if (library == NULL) { 3823 const char *sub_msg = " in absolute path, with error: "; 3824 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3825 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3826 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3827 // If we can't find the agent, exit. 3828 vm_exit_during_initialization(buf, NULL); 3829 FREE_C_HEAP_ARRAY(char, buf); 3830 } 3831 } else { 3832 // Try to load the agent from the standard dll directory 3833 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3834 name)) { 3835 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3836 } 3837 if (library == NULL) { // Try the local directory 3838 char ns[1] = {0}; 3839 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3840 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3841 } 3842 if (library == NULL) { 3843 const char *sub_msg = " on the library path, with error: "; 3844 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3845 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3846 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3847 // If we can't find the agent, exit. 3848 vm_exit_during_initialization(buf, NULL); 3849 FREE_C_HEAP_ARRAY(char, buf); 3850 } 3851 } 3852 } 3853 agent->set_os_lib(library); 3854 agent->set_valid(); 3855 } 3856 3857 // Find the OnLoad function. 3858 on_load_entry = 3859 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3860 false, 3861 on_load_symbols, 3862 num_symbol_entries)); 3863 return on_load_entry; 3864 } 3865 3866 // Find the JVM_OnLoad entry point 3867 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3868 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3869 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3870 } 3871 3872 // Find the Agent_OnLoad entry point 3873 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3874 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3875 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3876 } 3877 3878 // For backwards compatibility with -Xrun 3879 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3880 // treated like -agentpath: 3881 // Must be called before agent libraries are created 3882 void Threads::convert_vm_init_libraries_to_agents() { 3883 AgentLibrary* agent; 3884 AgentLibrary* next; 3885 3886 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3887 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3888 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3889 3890 // If there is an JVM_OnLoad function it will get called later, 3891 // otherwise see if there is an Agent_OnLoad 3892 if (on_load_entry == NULL) { 3893 on_load_entry = lookup_agent_on_load(agent); 3894 if (on_load_entry != NULL) { 3895 // switch it to the agent list -- so that Agent_OnLoad will be called, 3896 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3897 Arguments::convert_library_to_agent(agent); 3898 } else { 3899 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3900 } 3901 } 3902 } 3903 } 3904 3905 // Create agents for -agentlib: -agentpath: and converted -Xrun 3906 // Invokes Agent_OnLoad 3907 // Called very early -- before JavaThreads exist 3908 void Threads::create_vm_init_agents() { 3909 extern struct JavaVM_ main_vm; 3910 AgentLibrary* agent; 3911 3912 JvmtiExport::enter_onload_phase(); 3913 3914 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3915 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3916 3917 if (on_load_entry != NULL) { 3918 // Invoke the Agent_OnLoad function 3919 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3920 if (err != JNI_OK) { 3921 vm_exit_during_initialization("agent library failed to init", agent->name()); 3922 } 3923 } else { 3924 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3925 } 3926 } 3927 JvmtiExport::enter_primordial_phase(); 3928 } 3929 3930 extern "C" { 3931 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3932 } 3933 3934 void Threads::shutdown_vm_agents() { 3935 // Send any Agent_OnUnload notifications 3936 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3937 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3938 extern struct JavaVM_ main_vm; 3939 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3940 3941 // Find the Agent_OnUnload function. 3942 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3943 os::find_agent_function(agent, 3944 false, 3945 on_unload_symbols, 3946 num_symbol_entries)); 3947 3948 // Invoke the Agent_OnUnload function 3949 if (unload_entry != NULL) { 3950 JavaThread* thread = JavaThread::current(); 3951 ThreadToNativeFromVM ttn(thread); 3952 HandleMark hm(thread); 3953 (*unload_entry)(&main_vm); 3954 } 3955 } 3956 } 3957 3958 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3959 // Invokes JVM_OnLoad 3960 void Threads::create_vm_init_libraries() { 3961 extern struct JavaVM_ main_vm; 3962 AgentLibrary* agent; 3963 3964 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3965 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3966 3967 if (on_load_entry != NULL) { 3968 // Invoke the JVM_OnLoad function 3969 JavaThread* thread = JavaThread::current(); 3970 ThreadToNativeFromVM ttn(thread); 3971 HandleMark hm(thread); 3972 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3973 if (err != JNI_OK) { 3974 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3975 } 3976 } else { 3977 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3978 } 3979 } 3980 } 3981 3982 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3983 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3984 3985 JavaThread* java_thread = NULL; 3986 // Sequential search for now. Need to do better optimization later. 3987 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3988 oop tobj = thread->threadObj(); 3989 if (!thread->is_exiting() && 3990 tobj != NULL && 3991 java_tid == java_lang_Thread::thread_id(tobj)) { 3992 java_thread = thread; 3993 break; 3994 } 3995 } 3996 return java_thread; 3997 } 3998 3999 4000 // Last thread running calls java.lang.Shutdown.shutdown() 4001 void JavaThread::invoke_shutdown_hooks() { 4002 HandleMark hm(this); 4003 4004 // We could get here with a pending exception, if so clear it now. 4005 if (this->has_pending_exception()) { 4006 this->clear_pending_exception(); 4007 } 4008 4009 EXCEPTION_MARK; 4010 Klass* shutdown_klass = 4011 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 4012 THREAD); 4013 if (shutdown_klass != NULL) { 4014 // SystemDictionary::resolve_or_null will return null if there was 4015 // an exception. If we cannot load the Shutdown class, just don't 4016 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 4017 // and finalizers (if runFinalizersOnExit is set) won't be run. 4018 // Note that if a shutdown hook was registered or runFinalizersOnExit 4019 // was called, the Shutdown class would have already been loaded 4020 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 4021 JavaValue result(T_VOID); 4022 JavaCalls::call_static(&result, 4023 shutdown_klass, 4024 vmSymbols::shutdown_method_name(), 4025 vmSymbols::void_method_signature(), 4026 THREAD); 4027 } 4028 CLEAR_PENDING_EXCEPTION; 4029 } 4030 4031 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 4032 // the program falls off the end of main(). Another VM exit path is through 4033 // vm_exit() when the program calls System.exit() to return a value or when 4034 // there is a serious error in VM. The two shutdown paths are not exactly 4035 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 4036 // and VM_Exit op at VM level. 4037 // 4038 // Shutdown sequence: 4039 // + Shutdown native memory tracking if it is on 4040 // + Wait until we are the last non-daemon thread to execute 4041 // <-- every thing is still working at this moment --> 4042 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 4043 // shutdown hooks, run finalizers if finalization-on-exit 4044 // + Call before_exit(), prepare for VM exit 4045 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 4046 // currently the only user of this mechanism is File.deleteOnExit()) 4047 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 4048 // post thread end and vm death events to JVMTI, 4049 // stop signal thread 4050 // + Call JavaThread::exit(), it will: 4051 // > release JNI handle blocks, remove stack guard pages 4052 // > remove this thread from Threads list 4053 // <-- no more Java code from this thread after this point --> 4054 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 4055 // the compiler threads at safepoint 4056 // <-- do not use anything that could get blocked by Safepoint --> 4057 // + Disable tracing at JNI/JVM barriers 4058 // + Set _vm_exited flag for threads that are still running native code 4059 // + Delete this thread 4060 // + Call exit_globals() 4061 // > deletes tty 4062 // > deletes PerfMemory resources 4063 // + Return to caller 4064 4065 bool Threads::destroy_vm() { 4066 JavaThread* thread = JavaThread::current(); 4067 4068 #ifdef ASSERT 4069 _vm_complete = false; 4070 #endif 4071 // Wait until we are the last non-daemon thread to execute 4072 { MutexLocker nu(Threads_lock); 4073 while (Threads::number_of_non_daemon_threads() > 1) 4074 // This wait should make safepoint checks, wait without a timeout, 4075 // and wait as a suspend-equivalent condition. 4076 // 4077 // Note: If the FlatProfiler is running and this thread is waiting 4078 // for another non-daemon thread to finish, then the FlatProfiler 4079 // is waiting for the external suspend request on this thread to 4080 // complete. wait_for_ext_suspend_completion() will eventually 4081 // timeout, but that takes time. Making this wait a suspend- 4082 // equivalent condition solves that timeout problem. 4083 // 4084 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 4085 Mutex::_as_suspend_equivalent_flag); 4086 } 4087 4088 // Hang forever on exit if we are reporting an error. 4089 if (ShowMessageBoxOnError && is_error_reported()) { 4090 os::infinite_sleep(); 4091 } 4092 os::wait_for_keypress_at_exit(); 4093 4094 // run Java level shutdown hooks 4095 thread->invoke_shutdown_hooks(); 4096 4097 before_exit(thread); 4098 4099 thread->exit(true); 4100 4101 // Stop VM thread. 4102 { 4103 // 4945125 The vm thread comes to a safepoint during exit. 4104 // GC vm_operations can get caught at the safepoint, and the 4105 // heap is unparseable if they are caught. Grab the Heap_lock 4106 // to prevent this. The GC vm_operations will not be able to 4107 // queue until after the vm thread is dead. After this point, 4108 // we'll never emerge out of the safepoint before the VM exits. 4109 4110 MutexLocker ml(Heap_lock); 4111 4112 VMThread::wait_for_vm_thread_exit(); 4113 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4114 VMThread::destroy(); 4115 } 4116 4117 // clean up ideal graph printers 4118 #if defined(COMPILER2) && !defined(PRODUCT) 4119 IdealGraphPrinter::clean_up(); 4120 #endif 4121 4122 // Now, all Java threads are gone except daemon threads. Daemon threads 4123 // running Java code or in VM are stopped by the Safepoint. However, 4124 // daemon threads executing native code are still running. But they 4125 // will be stopped at native=>Java/VM barriers. Note that we can't 4126 // simply kill or suspend them, as it is inherently deadlock-prone. 4127 4128 VM_Exit::set_vm_exited(); 4129 4130 notify_vm_shutdown(); 4131 4132 delete thread; 4133 4134 #if INCLUDE_JVMCI 4135 if (JVMCICounterSize > 0) { 4136 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters); 4137 } 4138 #endif 4139 4140 // exit_globals() will delete tty 4141 exit_globals(); 4142 4143 LogConfiguration::finalize(); 4144 4145 return true; 4146 } 4147 4148 4149 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4150 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4151 return is_supported_jni_version(version); 4152 } 4153 4154 4155 jboolean Threads::is_supported_jni_version(jint version) { 4156 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4157 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4158 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4159 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4160 if (version == JNI_VERSION_9) return JNI_TRUE; 4161 return JNI_FALSE; 4162 } 4163 4164 4165 void Threads::add(JavaThread* p, bool force_daemon) { 4166 // The threads lock must be owned at this point 4167 assert_locked_or_safepoint(Threads_lock); 4168 4169 // See the comment for this method in thread.hpp for its purpose and 4170 // why it is called here. 4171 BarrierSet* bs = Universe::heap()->barrier_set(); 4172 bs->on_add_thread(p); 4173 4174 p->set_next(_thread_list); 4175 _thread_list = p; 4176 _number_of_threads++; 4177 oop threadObj = p->threadObj(); 4178 bool daemon = true; 4179 // Bootstrapping problem: threadObj can be null for initial 4180 // JavaThread (or for threads attached via JNI) 4181 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4182 _number_of_non_daemon_threads++; 4183 daemon = false; 4184 } 4185 4186 ThreadService::add_thread(p, daemon); 4187 4188 // Possible GC point. 4189 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p)); 4190 } 4191 4192 void Threads::remove(JavaThread* p) { 4193 // Extra scope needed for Thread_lock, so we can check 4194 // that we do not remove thread without safepoint code notice 4195 { MutexLocker ml(Threads_lock); 4196 4197 assert(includes(p), "p must be present"); 4198 4199 JavaThread* current = _thread_list; 4200 JavaThread* prev = NULL; 4201 4202 while (current != p) { 4203 prev = current; 4204 current = current->next(); 4205 } 4206 4207 if (prev) { 4208 prev->set_next(current->next()); 4209 } else { 4210 _thread_list = p->next(); 4211 } 4212 _number_of_threads--; 4213 oop threadObj = p->threadObj(); 4214 bool daemon = true; 4215 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4216 _number_of_non_daemon_threads--; 4217 daemon = false; 4218 4219 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4220 // on destroy_vm will wake up. 4221 if (number_of_non_daemon_threads() == 1) { 4222 Threads_lock->notify_all(); 4223 } 4224 } 4225 ThreadService::remove_thread(p, daemon); 4226 4227 // Make sure that safepoint code disregard this thread. This is needed since 4228 // the thread might mess around with locks after this point. This can cause it 4229 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4230 // of this thread since it is removed from the queue. 4231 p->set_terminated_value(); 4232 } // unlock Threads_lock 4233 4234 // Since Events::log uses a lock, we grab it outside the Threads_lock 4235 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p)); 4236 } 4237 4238 // Threads_lock must be held when this is called (or must be called during a safepoint) 4239 bool Threads::includes(JavaThread* p) { 4240 assert(Threads_lock->is_locked(), "sanity check"); 4241 ALL_JAVA_THREADS(q) { 4242 if (q == p) { 4243 return true; 4244 } 4245 } 4246 return false; 4247 } 4248 4249 // Operations on the Threads list for GC. These are not explicitly locked, 4250 // but the garbage collector must provide a safe context for them to run. 4251 // In particular, these things should never be called when the Threads_lock 4252 // is held by some other thread. (Note: the Safepoint abstraction also 4253 // uses the Threads_lock to guarantee this property. It also makes sure that 4254 // all threads gets blocked when exiting or starting). 4255 4256 void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) { 4257 ALL_JAVA_THREADS(p) { 4258 p->oops_do(f, cf); 4259 } 4260 VMThread::vm_thread()->oops_do(f, cf); 4261 } 4262 4263 void Threads::change_thread_claim_parity() { 4264 // Set the new claim parity. 4265 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2, 4266 "Not in range."); 4267 _thread_claim_parity++; 4268 if (_thread_claim_parity == 3) _thread_claim_parity = 1; 4269 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2, 4270 "Not in range."); 4271 } 4272 4273 #ifdef ASSERT 4274 void Threads::assert_all_threads_claimed() { 4275 ALL_JAVA_THREADS(p) { 4276 const int thread_parity = p->oops_do_parity(); 4277 assert((thread_parity == _thread_claim_parity), 4278 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity); 4279 } 4280 } 4281 #endif // ASSERT 4282 4283 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) { 4284 int cp = Threads::thread_claim_parity(); 4285 ALL_JAVA_THREADS(p) { 4286 if (p->claim_oops_do(is_par, cp)) { 4287 p->oops_do(f, cf); 4288 } 4289 } 4290 VMThread* vmt = VMThread::vm_thread(); 4291 if (vmt->claim_oops_do(is_par, cp)) { 4292 vmt->oops_do(f, cf); 4293 } 4294 } 4295 4296 #if INCLUDE_ALL_GCS 4297 // Used by ParallelScavenge 4298 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4299 ALL_JAVA_THREADS(p) { 4300 q->enqueue(new ThreadRootsTask(p)); 4301 } 4302 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4303 } 4304 4305 // Used by Parallel Old 4306 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4307 ALL_JAVA_THREADS(p) { 4308 q->enqueue(new ThreadRootsMarkingTask(p)); 4309 } 4310 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4311 } 4312 #endif // INCLUDE_ALL_GCS 4313 4314 void Threads::nmethods_do(CodeBlobClosure* cf) { 4315 ALL_JAVA_THREADS(p) { 4316 // This is used by the code cache sweeper to mark nmethods that are active 4317 // on the stack of a Java thread. Ignore the sweeper thread itself to avoid 4318 // marking CodeCacheSweeperThread::_scanned_compiled_method as active. 4319 if(!p->is_Code_cache_sweeper_thread()) { 4320 p->nmethods_do(cf); 4321 } 4322 } 4323 } 4324 4325 void Threads::metadata_do(void f(Metadata*)) { 4326 ALL_JAVA_THREADS(p) { 4327 p->metadata_do(f); 4328 } 4329 } 4330 4331 class ThreadHandlesClosure : public ThreadClosure { 4332 void (*_f)(Metadata*); 4333 public: 4334 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4335 virtual void do_thread(Thread* thread) { 4336 thread->metadata_handles_do(_f); 4337 } 4338 }; 4339 4340 void Threads::metadata_handles_do(void f(Metadata*)) { 4341 // Only walk the Handles in Thread. 4342 ThreadHandlesClosure handles_closure(f); 4343 threads_do(&handles_closure); 4344 } 4345 4346 void Threads::deoptimized_wrt_marked_nmethods() { 4347 ALL_JAVA_THREADS(p) { 4348 p->deoptimized_wrt_marked_nmethods(); 4349 } 4350 } 4351 4352 4353 // Get count Java threads that are waiting to enter the specified monitor. 4354 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4355 address monitor, 4356 bool doLock) { 4357 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4358 "must grab Threads_lock or be at safepoint"); 4359 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4360 4361 int i = 0; 4362 { 4363 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4364 ALL_JAVA_THREADS(p) { 4365 if (!p->can_call_java()) continue; 4366 4367 address pending = (address)p->current_pending_monitor(); 4368 if (pending == monitor) { // found a match 4369 if (i < count) result->append(p); // save the first count matches 4370 i++; 4371 } 4372 } 4373 } 4374 return result; 4375 } 4376 4377 4378 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, 4379 bool doLock) { 4380 assert(doLock || 4381 Threads_lock->owned_by_self() || 4382 SafepointSynchronize::is_at_safepoint(), 4383 "must grab Threads_lock or be at safepoint"); 4384 4385 // NULL owner means not locked so we can skip the search 4386 if (owner == NULL) return NULL; 4387 4388 { 4389 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4390 ALL_JAVA_THREADS(p) { 4391 // first, see if owner is the address of a Java thread 4392 if (owner == (address)p) return p; 4393 } 4394 } 4395 // Cannot assert on lack of success here since this function may be 4396 // used by code that is trying to report useful problem information 4397 // like deadlock detection. 4398 if (UseHeavyMonitors) return NULL; 4399 4400 // If we didn't find a matching Java thread and we didn't force use of 4401 // heavyweight monitors, then the owner is the stack address of the 4402 // Lock Word in the owning Java thread's stack. 4403 // 4404 JavaThread* the_owner = NULL; 4405 { 4406 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4407 ALL_JAVA_THREADS(q) { 4408 if (q->is_lock_owned(owner)) { 4409 the_owner = q; 4410 break; 4411 } 4412 } 4413 } 4414 // cannot assert on lack of success here; see above comment 4415 return the_owner; 4416 } 4417 4418 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4419 void Threads::print_on(outputStream* st, bool print_stacks, 4420 bool internal_format, bool print_concurrent_locks) { 4421 char buf[32]; 4422 st->print_raw_cr(os::local_time_string(buf, sizeof(buf))); 4423 4424 st->print_cr("Full thread dump %s (%s %s):", 4425 Abstract_VM_Version::vm_name(), 4426 Abstract_VM_Version::vm_release(), 4427 Abstract_VM_Version::vm_info_string()); 4428 st->cr(); 4429 4430 #if INCLUDE_SERVICES 4431 // Dump concurrent locks 4432 ConcurrentLocksDump concurrent_locks; 4433 if (print_concurrent_locks) { 4434 concurrent_locks.dump_at_safepoint(); 4435 } 4436 #endif // INCLUDE_SERVICES 4437 4438 ALL_JAVA_THREADS(p) { 4439 ResourceMark rm; 4440 p->print_on(st); 4441 if (print_stacks) { 4442 if (internal_format) { 4443 p->trace_stack(); 4444 } else { 4445 p->print_stack_on(st); 4446 } 4447 } 4448 st->cr(); 4449 #if INCLUDE_SERVICES 4450 if (print_concurrent_locks) { 4451 concurrent_locks.print_locks_on(p, st); 4452 } 4453 #endif // INCLUDE_SERVICES 4454 } 4455 4456 VMThread::vm_thread()->print_on(st); 4457 st->cr(); 4458 Universe::heap()->print_gc_threads_on(st); 4459 WatcherThread* wt = WatcherThread::watcher_thread(); 4460 if (wt != NULL) { 4461 wt->print_on(st); 4462 st->cr(); 4463 } 4464 st->flush(); 4465 } 4466 4467 void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf, 4468 int buflen, bool* found_current) { 4469 if (this_thread != NULL) { 4470 bool is_current = (current == this_thread); 4471 *found_current = *found_current || is_current; 4472 st->print("%s", is_current ? "=>" : " "); 4473 4474 st->print(PTR_FORMAT, p2i(this_thread)); 4475 st->print(" "); 4476 this_thread->print_on_error(st, buf, buflen); 4477 st->cr(); 4478 } 4479 } 4480 4481 class PrintOnErrorClosure : public ThreadClosure { 4482 outputStream* _st; 4483 Thread* _current; 4484 char* _buf; 4485 int _buflen; 4486 bool* _found_current; 4487 public: 4488 PrintOnErrorClosure(outputStream* st, Thread* current, char* buf, 4489 int buflen, bool* found_current) : 4490 _st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {} 4491 4492 virtual void do_thread(Thread* thread) { 4493 Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current); 4494 } 4495 }; 4496 4497 // Threads::print_on_error() is called by fatal error handler. It's possible 4498 // that VM is not at safepoint and/or current thread is inside signal handler. 4499 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4500 // memory (even in resource area), it might deadlock the error handler. 4501 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4502 int buflen) { 4503 bool found_current = false; 4504 st->print_cr("Java Threads: ( => current thread )"); 4505 ALL_JAVA_THREADS(thread) { 4506 print_on_error(thread, st, current, buf, buflen, &found_current); 4507 } 4508 st->cr(); 4509 4510 st->print_cr("Other Threads:"); 4511 print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current); 4512 print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current); 4513 4514 PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current); 4515 Universe::heap()->gc_threads_do(&print_closure); 4516 4517 if (!found_current) { 4518 st->cr(); 4519 st->print("=>" PTR_FORMAT " (exited) ", p2i(current)); 4520 current->print_on_error(st, buf, buflen); 4521 st->cr(); 4522 } 4523 st->cr(); 4524 st->print_cr("Threads with active compile tasks:"); 4525 print_threads_compiling(st, buf, buflen); 4526 } 4527 4528 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) { 4529 ALL_JAVA_THREADS(thread) { 4530 if (thread->is_Compiler_thread()) { 4531 CompilerThread* ct = (CompilerThread*) thread; 4532 if (ct->task() != NULL) { 4533 thread->print_name_on_error(st, buf, buflen); 4534 ct->task()->print(st, NULL, true, true); 4535 } 4536 } 4537 } 4538 } 4539 4540 4541 // Internal SpinLock and Mutex 4542 // Based on ParkEvent 4543 4544 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4545 // 4546 // We employ SpinLocks _only for low-contention, fixed-length 4547 // short-duration critical sections where we're concerned 4548 // about native mutex_t or HotSpot Mutex:: latency. 4549 // The mux construct provides a spin-then-block mutual exclusion 4550 // mechanism. 4551 // 4552 // Testing has shown that contention on the ListLock guarding gFreeList 4553 // is common. If we implement ListLock as a simple SpinLock it's common 4554 // for the JVM to devolve to yielding with little progress. This is true 4555 // despite the fact that the critical sections protected by ListLock are 4556 // extremely short. 4557 // 4558 // TODO-FIXME: ListLock should be of type SpinLock. 4559 // We should make this a 1st-class type, integrated into the lock 4560 // hierarchy as leaf-locks. Critically, the SpinLock structure 4561 // should have sufficient padding to avoid false-sharing and excessive 4562 // cache-coherency traffic. 4563 4564 4565 typedef volatile int SpinLockT; 4566 4567 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4568 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4569 return; // normal fast-path return 4570 } 4571 4572 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4573 TEVENT(SpinAcquire - ctx); 4574 int ctr = 0; 4575 int Yields = 0; 4576 for (;;) { 4577 while (*adr != 0) { 4578 ++ctr; 4579 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4580 if (Yields > 5) { 4581 os::naked_short_sleep(1); 4582 } else { 4583 os::naked_yield(); 4584 ++Yields; 4585 } 4586 } else { 4587 SpinPause(); 4588 } 4589 } 4590 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4591 } 4592 } 4593 4594 void Thread::SpinRelease(volatile int * adr) { 4595 assert(*adr != 0, "invariant"); 4596 OrderAccess::fence(); // guarantee at least release consistency. 4597 // Roach-motel semantics. 4598 // It's safe if subsequent LDs and STs float "up" into the critical section, 4599 // but prior LDs and STs within the critical section can't be allowed 4600 // to reorder or float past the ST that releases the lock. 4601 // Loads and stores in the critical section - which appear in program 4602 // order before the store that releases the lock - must also appear 4603 // before the store that releases the lock in memory visibility order. 4604 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4605 // the ST of 0 into the lock-word which releases the lock, so fence 4606 // more than covers this on all platforms. 4607 *adr = 0; 4608 } 4609 4610 // muxAcquire and muxRelease: 4611 // 4612 // * muxAcquire and muxRelease support a single-word lock-word construct. 4613 // The LSB of the word is set IFF the lock is held. 4614 // The remainder of the word points to the head of a singly-linked list 4615 // of threads blocked on the lock. 4616 // 4617 // * The current implementation of muxAcquire-muxRelease uses its own 4618 // dedicated Thread._MuxEvent instance. If we're interested in 4619 // minimizing the peak number of extant ParkEvent instances then 4620 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4621 // as certain invariants were satisfied. Specifically, care would need 4622 // to be taken with regards to consuming unpark() "permits". 4623 // A safe rule of thumb is that a thread would never call muxAcquire() 4624 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4625 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4626 // consume an unpark() permit intended for monitorenter, for instance. 4627 // One way around this would be to widen the restricted-range semaphore 4628 // implemented in park(). Another alternative would be to provide 4629 // multiple instances of the PlatformEvent() for each thread. One 4630 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4631 // 4632 // * Usage: 4633 // -- Only as leaf locks 4634 // -- for short-term locking only as muxAcquire does not perform 4635 // thread state transitions. 4636 // 4637 // Alternatives: 4638 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4639 // but with parking or spin-then-park instead of pure spinning. 4640 // * Use Taura-Oyama-Yonenzawa locks. 4641 // * It's possible to construct a 1-0 lock if we encode the lockword as 4642 // (List,LockByte). Acquire will CAS the full lockword while Release 4643 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4644 // acquiring threads use timers (ParkTimed) to detect and recover from 4645 // the stranding window. Thread/Node structures must be aligned on 256-byte 4646 // boundaries by using placement-new. 4647 // * Augment MCS with advisory back-link fields maintained with CAS(). 4648 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4649 // The validity of the backlinks must be ratified before we trust the value. 4650 // If the backlinks are invalid the exiting thread must back-track through the 4651 // the forward links, which are always trustworthy. 4652 // * Add a successor indication. The LockWord is currently encoded as 4653 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4654 // to provide the usual futile-wakeup optimization. 4655 // See RTStt for details. 4656 // * Consider schedctl.sc_nopreempt to cover the critical section. 4657 // 4658 4659 4660 typedef volatile intptr_t MutexT; // Mux Lock-word 4661 enum MuxBits { LOCKBIT = 1 }; 4662 4663 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4664 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4665 if (w == 0) return; 4666 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4667 return; 4668 } 4669 4670 TEVENT(muxAcquire - Contention); 4671 ParkEvent * const Self = Thread::current()->_MuxEvent; 4672 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4673 for (;;) { 4674 int its = (os::is_MP() ? 100 : 0) + 1; 4675 4676 // Optional spin phase: spin-then-park strategy 4677 while (--its >= 0) { 4678 w = *Lock; 4679 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4680 return; 4681 } 4682 } 4683 4684 Self->reset(); 4685 Self->OnList = intptr_t(Lock); 4686 // The following fence() isn't _strictly necessary as the subsequent 4687 // CAS() both serializes execution and ratifies the fetched *Lock value. 4688 OrderAccess::fence(); 4689 for (;;) { 4690 w = *Lock; 4691 if ((w & LOCKBIT) == 0) { 4692 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4693 Self->OnList = 0; // hygiene - allows stronger asserts 4694 return; 4695 } 4696 continue; // Interference -- *Lock changed -- Just retry 4697 } 4698 assert(w & LOCKBIT, "invariant"); 4699 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4700 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4701 } 4702 4703 while (Self->OnList != 0) { 4704 Self->park(); 4705 } 4706 } 4707 } 4708 4709 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4710 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4711 if (w == 0) return; 4712 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4713 return; 4714 } 4715 4716 TEVENT(muxAcquire - Contention); 4717 ParkEvent * ReleaseAfter = NULL; 4718 if (ev == NULL) { 4719 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4720 } 4721 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4722 for (;;) { 4723 guarantee(ev->OnList == 0, "invariant"); 4724 int its = (os::is_MP() ? 100 : 0) + 1; 4725 4726 // Optional spin phase: spin-then-park strategy 4727 while (--its >= 0) { 4728 w = *Lock; 4729 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4730 if (ReleaseAfter != NULL) { 4731 ParkEvent::Release(ReleaseAfter); 4732 } 4733 return; 4734 } 4735 } 4736 4737 ev->reset(); 4738 ev->OnList = intptr_t(Lock); 4739 // The following fence() isn't _strictly necessary as the subsequent 4740 // CAS() both serializes execution and ratifies the fetched *Lock value. 4741 OrderAccess::fence(); 4742 for (;;) { 4743 w = *Lock; 4744 if ((w & LOCKBIT) == 0) { 4745 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4746 ev->OnList = 0; 4747 // We call ::Release while holding the outer lock, thus 4748 // artificially lengthening the critical section. 4749 // Consider deferring the ::Release() until the subsequent unlock(), 4750 // after we've dropped the outer lock. 4751 if (ReleaseAfter != NULL) { 4752 ParkEvent::Release(ReleaseAfter); 4753 } 4754 return; 4755 } 4756 continue; // Interference -- *Lock changed -- Just retry 4757 } 4758 assert(w & LOCKBIT, "invariant"); 4759 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4760 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4761 } 4762 4763 while (ev->OnList != 0) { 4764 ev->park(); 4765 } 4766 } 4767 } 4768 4769 // Release() must extract a successor from the list and then wake that thread. 4770 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4771 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4772 // Release() would : 4773 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4774 // (B) Extract a successor from the private list "in-hand" 4775 // (C) attempt to CAS() the residual back into *Lock over null. 4776 // If there were any newly arrived threads and the CAS() would fail. 4777 // In that case Release() would detach the RATs, re-merge the list in-hand 4778 // with the RATs and repeat as needed. Alternately, Release() might 4779 // detach and extract a successor, but then pass the residual list to the wakee. 4780 // The wakee would be responsible for reattaching and remerging before it 4781 // competed for the lock. 4782 // 4783 // Both "pop" and DMR are immune from ABA corruption -- there can be 4784 // multiple concurrent pushers, but only one popper or detacher. 4785 // This implementation pops from the head of the list. This is unfair, 4786 // but tends to provide excellent throughput as hot threads remain hot. 4787 // (We wake recently run threads first). 4788 // 4789 // All paths through muxRelease() will execute a CAS. 4790 // Release consistency -- We depend on the CAS in muxRelease() to provide full 4791 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4792 // executed within the critical section are complete and globally visible before the 4793 // store (CAS) to the lock-word that releases the lock becomes globally visible. 4794 void Thread::muxRelease(volatile intptr_t * Lock) { 4795 for (;;) { 4796 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4797 assert(w & LOCKBIT, "invariant"); 4798 if (w == LOCKBIT) return; 4799 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4800 assert(List != NULL, "invariant"); 4801 assert(List->OnList == intptr_t(Lock), "invariant"); 4802 ParkEvent * const nxt = List->ListNext; 4803 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4804 4805 // The following CAS() releases the lock and pops the head element. 4806 // The CAS() also ratifies the previously fetched lock-word value. 4807 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4808 continue; 4809 } 4810 List->OnList = 0; 4811 OrderAccess::fence(); 4812 List->unpark(); 4813 return; 4814 } 4815 } 4816 4817 4818 void Threads::verify() { 4819 ALL_JAVA_THREADS(p) { 4820 p->verify(); 4821 } 4822 VMThread* thread = VMThread::vm_thread(); 4823 if (thread != NULL) thread->verify(); 4824 }