1 /* 2 * Copyright (c) 1997, 2016, 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/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/codeCache.hpp" 31 #include "code/codeCacheExtensions.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/universe.inline.hpp" 47 #include "oops/instanceKlass.hpp" 48 #include "oops/objArrayOop.hpp" 49 #include "oops/oop.inline.hpp" 50 #include "oops/symbol.hpp" 51 #include "oops/verifyOopClosure.hpp" 52 #include "prims/jvm_misc.hpp" 53 #include "prims/jvmtiExport.hpp" 54 #include "prims/jvmtiThreadState.hpp" 55 #include "prims/privilegedStack.hpp" 56 #include "runtime/arguments.hpp" 57 #include "runtime/atomic.inline.hpp" 58 #include "runtime/biasedLocking.hpp" 59 #include "runtime/commandLineFlagConstraintList.hpp" 60 #include "runtime/commandLineFlagRangeList.hpp" 61 #include "runtime/deoptimization.hpp" 62 #include "runtime/fprofiler.hpp" 63 #include "runtime/frame.inline.hpp" 64 #include "runtime/globals.hpp" 65 #include "runtime/init.hpp" 66 #include "runtime/interfaceSupport.hpp" 67 #include "runtime/java.hpp" 68 #include "runtime/javaCalls.hpp" 69 #include "runtime/jniPeriodicChecker.hpp" 70 #include "runtime/logTimer.hpp" 71 #include "runtime/memprofiler.hpp" 72 #include "runtime/mutexLocker.hpp" 73 #include "runtime/objectMonitor.hpp" 74 #include "runtime/orderAccess.inline.hpp" 75 #include "runtime/osThread.hpp" 76 #include "runtime/safepoint.hpp" 77 #include "runtime/sharedRuntime.hpp" 78 #include "runtime/statSampler.hpp" 79 #include "runtime/stubRoutines.hpp" 80 #include "runtime/sweeper.hpp" 81 #include "runtime/task.hpp" 82 #include "runtime/thread.inline.hpp" 83 #include "runtime/threadCritical.hpp" 84 #include "runtime/vframe.hpp" 85 #include "runtime/vframeArray.hpp" 86 #include "runtime/vframe_hp.hpp" 87 #include "runtime/vmThread.hpp" 88 #include "runtime/vm_operations.hpp" 89 #include "runtime/vm_version.hpp" 90 #include "services/attachListener.hpp" 91 #include "services/management.hpp" 92 #include "services/memTracker.hpp" 93 #include "services/threadService.hpp" 94 #include "trace/traceMacros.hpp" 95 #include "trace/tracing.hpp" 96 #include "utilities/defaultStream.hpp" 97 #include "utilities/dtrace.hpp" 98 #include "utilities/events.hpp" 99 #include "utilities/macros.hpp" 100 #include "utilities/preserveException.hpp" 101 #if INCLUDE_ALL_GCS 102 #include "gc/cms/concurrentMarkSweepThread.hpp" 103 #include "gc/g1/concurrentMarkThread.inline.hpp" 104 #include "gc/parallel/pcTasks.hpp" 105 #endif // INCLUDE_ALL_GCS 106 #if INCLUDE_JVMCI 107 #include "jvmci/jvmciCompiler.hpp" 108 #include "jvmci/jvmciRuntime.hpp" 109 #endif 110 #ifdef COMPILER1 111 #include "c1/c1_Compiler.hpp" 112 #endif 113 #ifdef COMPILER2 114 #include "opto/c2compiler.hpp" 115 #include "opto/idealGraphPrinter.hpp" 116 #endif 117 #if INCLUDE_RTM_OPT 118 #include "runtime/rtmLocking.hpp" 119 #endif 120 121 #ifdef DTRACE_ENABLED 122 123 // Only bother with this argument setup if dtrace is available 124 125 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 126 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 127 128 #define DTRACE_THREAD_PROBE(probe, javathread) \ 129 { \ 130 ResourceMark rm(this); \ 131 int len = 0; \ 132 const char* name = (javathread)->get_thread_name(); \ 133 len = strlen(name); \ 134 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 135 (char *) name, len, \ 136 java_lang_Thread::thread_id((javathread)->threadObj()), \ 137 (uintptr_t) (javathread)->osthread()->thread_id(), \ 138 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 139 } 140 141 #else // ndef DTRACE_ENABLED 142 143 #define DTRACE_THREAD_PROBE(probe, javathread) 144 145 #endif // ndef DTRACE_ENABLED 146 147 #ifndef USE_LIBRARY_BASED_TLS_ONLY 148 // Current thread is maintained as a thread-local variable 149 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL; 150 #endif 151 152 // Class hierarchy 153 // - Thread 154 // - VMThread 155 // - WatcherThread 156 // - ConcurrentMarkSweepThread 157 // - JavaThread 158 // - CompilerThread 159 160 // ======= Thread ======== 161 // Support for forcing alignment of thread objects for biased locking 162 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 163 if (UseBiasedLocking) { 164 const int alignment = markOopDesc::biased_lock_alignment; 165 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 166 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 167 : AllocateHeap(aligned_size, flags, CURRENT_PC, 168 AllocFailStrategy::RETURN_NULL); 169 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 170 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 171 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 172 "JavaThread alignment code overflowed allocated storage"); 173 if (aligned_addr != real_malloc_addr) { 174 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 175 p2i(real_malloc_addr), 176 p2i(aligned_addr)); 177 } 178 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 179 return aligned_addr; 180 } else { 181 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 182 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 183 } 184 } 185 186 void Thread::operator delete(void* p) { 187 if (UseBiasedLocking) { 188 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 189 FreeHeap(real_malloc_addr); 190 } else { 191 FreeHeap(p); 192 } 193 } 194 195 196 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 197 // JavaThread 198 199 200 Thread::Thread() { 201 // stack and get_thread 202 set_stack_base(NULL); 203 set_stack_size(0); 204 set_self_raw_id(0); 205 set_lgrp_id(-1); 206 DEBUG_ONLY(clear_suspendible_thread();) 207 208 // allocated data structures 209 set_osthread(NULL); 210 set_resource_area(new (mtThread)ResourceArea()); 211 DEBUG_ONLY(_current_resource_mark = NULL;) 212 set_handle_area(new (mtThread) HandleArea(NULL)); 213 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 214 set_active_handles(NULL); 215 set_free_handle_block(NULL); 216 set_last_handle_mark(NULL); 217 218 // This initial value ==> never claimed. 219 _oops_do_parity = 0; 220 221 // the handle mark links itself to last_handle_mark 222 new HandleMark(this); 223 224 // plain initialization 225 debug_only(_owned_locks = NULL;) 226 debug_only(_allow_allocation_count = 0;) 227 NOT_PRODUCT(_allow_safepoint_count = 0;) 228 NOT_PRODUCT(_skip_gcalot = false;) 229 _jvmti_env_iteration_count = 0; 230 set_allocated_bytes(0); 231 _vm_operation_started_count = 0; 232 _vm_operation_completed_count = 0; 233 _current_pending_monitor = NULL; 234 _current_pending_monitor_is_from_java = true; 235 _current_waiting_monitor = NULL; 236 _num_nested_signal = 0; 237 omFreeList = NULL; 238 omFreeCount = 0; 239 omFreeProvision = 32; 240 omInUseList = NULL; 241 omInUseCount = 0; 242 243 #ifdef ASSERT 244 _visited_for_critical_count = false; 245 #endif 246 247 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, 248 Monitor::_safepoint_check_sometimes); 249 _suspend_flags = 0; 250 251 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 252 _hashStateX = os::random(); 253 _hashStateY = 842502087; 254 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 255 _hashStateW = 273326509; 256 257 _OnTrap = 0; 258 _schedctl = NULL; 259 _Stalled = 0; 260 _TypeTag = 0x2BAD; 261 262 // Many of the following fields are effectively final - immutable 263 // Note that nascent threads can't use the Native Monitor-Mutex 264 // construct until the _MutexEvent is initialized ... 265 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 266 // we might instead use a stack of ParkEvents that we could provision on-demand. 267 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 268 // and ::Release() 269 _ParkEvent = ParkEvent::Allocate(this); 270 _SleepEvent = ParkEvent::Allocate(this); 271 _MutexEvent = ParkEvent::Allocate(this); 272 _MuxEvent = ParkEvent::Allocate(this); 273 274 #ifdef CHECK_UNHANDLED_OOPS 275 if (CheckUnhandledOops) { 276 _unhandled_oops = new UnhandledOops(this); 277 } 278 #endif // CHECK_UNHANDLED_OOPS 279 #ifdef ASSERT 280 if (UseBiasedLocking) { 281 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 282 assert(this == _real_malloc_address || 283 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 284 "bug in forced alignment of thread objects"); 285 } 286 #endif // ASSERT 287 } 288 289 void Thread::initialize_thread_current() { 290 #ifndef USE_LIBRARY_BASED_TLS_ONLY 291 assert(_thr_current == NULL, "Thread::current already initialized"); 292 _thr_current = this; 293 #endif 294 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized"); 295 ThreadLocalStorage::set_thread(this); 296 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 297 } 298 299 void Thread::clear_thread_current() { 300 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 301 #ifndef USE_LIBRARY_BASED_TLS_ONLY 302 _thr_current = NULL; 303 #endif 304 ThreadLocalStorage::set_thread(NULL); 305 } 306 307 void Thread::record_stack_base_and_size() { 308 set_stack_base(os::current_stack_base()); 309 set_stack_size(os::current_stack_size()); 310 // CR 7190089: on Solaris, primordial thread's stack is adjusted 311 // in initialize_thread(). Without the adjustment, stack size is 312 // incorrect if stack is set to unlimited (ulimit -s unlimited). 313 // So far, only Solaris has real implementation of initialize_thread(). 314 // 315 // set up any platform-specific state. 316 os::initialize_thread(this); 317 318 // Set stack limits after thread is initialized. 319 if (is_Java_thread()) { 320 ((JavaThread*) this)->set_stack_overflow_limit(); 321 ((JavaThread*) this)->set_reserved_stack_activation(stack_base()); 322 } 323 #if INCLUDE_NMT 324 // record thread's native stack, stack grows downward 325 MemTracker::record_thread_stack(stack_end(), stack_size()); 326 #endif // INCLUDE_NMT 327 } 328 329 330 Thread::~Thread() { 331 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 332 ObjectSynchronizer::omFlush(this); 333 334 EVENT_THREAD_DESTRUCT(this); 335 336 // stack_base can be NULL if the thread is never started or exited before 337 // record_stack_base_and_size called. Although, we would like to ensure 338 // that all started threads do call record_stack_base_and_size(), there is 339 // not proper way to enforce that. 340 #if INCLUDE_NMT 341 if (_stack_base != NULL) { 342 MemTracker::release_thread_stack(stack_end(), stack_size()); 343 #ifdef ASSERT 344 set_stack_base(NULL); 345 #endif 346 } 347 #endif // INCLUDE_NMT 348 349 // deallocate data structures 350 delete resource_area(); 351 // since the handle marks are using the handle area, we have to deallocated the root 352 // handle mark before deallocating the thread's handle area, 353 assert(last_handle_mark() != NULL, "check we have an element"); 354 delete last_handle_mark(); 355 assert(last_handle_mark() == NULL, "check we have reached the end"); 356 357 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 358 // We NULL out the fields for good hygiene. 359 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 360 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 361 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 362 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 363 364 delete handle_area(); 365 delete metadata_handles(); 366 367 // osthread() can be NULL, if creation of thread failed. 368 if (osthread() != NULL) os::free_thread(osthread()); 369 370 delete _SR_lock; 371 372 // clear Thread::current if thread is deleting itself. 373 // Needed to ensure JNI correctly detects non-attached threads. 374 if (this == Thread::current()) { 375 clear_thread_current(); 376 } 377 378 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 379 } 380 381 // NOTE: dummy function for assertion purpose. 382 void Thread::run() { 383 ShouldNotReachHere(); 384 } 385 386 #ifdef ASSERT 387 // Private method to check for dangling thread pointer 388 void check_for_dangling_thread_pointer(Thread *thread) { 389 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 390 "possibility of dangling Thread pointer"); 391 } 392 #endif 393 394 ThreadPriority Thread::get_priority(const Thread* const thread) { 395 ThreadPriority priority; 396 // Can return an error! 397 (void)os::get_priority(thread, priority); 398 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 399 return priority; 400 } 401 402 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 403 debug_only(check_for_dangling_thread_pointer(thread);) 404 // Can return an error! 405 (void)os::set_priority(thread, priority); 406 } 407 408 409 void Thread::start(Thread* thread) { 410 // Start is different from resume in that its safety is guaranteed by context or 411 // being called from a Java method synchronized on the Thread object. 412 if (!DisableStartThread) { 413 if (thread->is_Java_thread()) { 414 // Initialize the thread state to RUNNABLE before starting this thread. 415 // Can not set it after the thread started because we do not know the 416 // exact thread state at that time. It could be in MONITOR_WAIT or 417 // in SLEEPING or some other state. 418 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 419 java_lang_Thread::RUNNABLE); 420 } 421 os::start_thread(thread); 422 } 423 } 424 425 // Enqueue a VM_Operation to do the job for us - sometime later 426 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 427 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 428 VMThread::execute(vm_stop); 429 } 430 431 432 // Check if an external suspend request has completed (or has been 433 // cancelled). Returns true if the thread is externally suspended and 434 // false otherwise. 435 // 436 // The bits parameter returns information about the code path through 437 // the routine. Useful for debugging: 438 // 439 // set in is_ext_suspend_completed(): 440 // 0x00000001 - routine was entered 441 // 0x00000010 - routine return false at end 442 // 0x00000100 - thread exited (return false) 443 // 0x00000200 - suspend request cancelled (return false) 444 // 0x00000400 - thread suspended (return true) 445 // 0x00001000 - thread is in a suspend equivalent state (return true) 446 // 0x00002000 - thread is native and walkable (return true) 447 // 0x00004000 - thread is native_trans and walkable (needed retry) 448 // 449 // set in wait_for_ext_suspend_completion(): 450 // 0x00010000 - routine was entered 451 // 0x00020000 - suspend request cancelled before loop (return false) 452 // 0x00040000 - thread suspended before loop (return true) 453 // 0x00080000 - suspend request cancelled in loop (return false) 454 // 0x00100000 - thread suspended in loop (return true) 455 // 0x00200000 - suspend not completed during retry loop (return false) 456 457 // Helper class for tracing suspend wait debug bits. 458 // 459 // 0x00000100 indicates that the target thread exited before it could 460 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 461 // 0x00080000 each indicate a cancelled suspend request so they don't 462 // count as wait failures either. 463 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 464 465 class TraceSuspendDebugBits : public StackObj { 466 private: 467 JavaThread * jt; 468 bool is_wait; 469 bool called_by_wait; // meaningful when !is_wait 470 uint32_t * bits; 471 472 public: 473 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 474 uint32_t *_bits) { 475 jt = _jt; 476 is_wait = _is_wait; 477 called_by_wait = _called_by_wait; 478 bits = _bits; 479 } 480 481 ~TraceSuspendDebugBits() { 482 if (!is_wait) { 483 #if 1 484 // By default, don't trace bits for is_ext_suspend_completed() calls. 485 // That trace is very chatty. 486 return; 487 #else 488 if (!called_by_wait) { 489 // If tracing for is_ext_suspend_completed() is enabled, then only 490 // trace calls to it from wait_for_ext_suspend_completion() 491 return; 492 } 493 #endif 494 } 495 496 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 497 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 498 MutexLocker ml(Threads_lock); // needed for get_thread_name() 499 ResourceMark rm; 500 501 tty->print_cr( 502 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 503 jt->get_thread_name(), *bits); 504 505 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 506 } 507 } 508 } 509 }; 510 #undef DEBUG_FALSE_BITS 511 512 513 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 514 uint32_t *bits) { 515 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 516 517 bool did_trans_retry = false; // only do thread_in_native_trans retry once 518 bool do_trans_retry; // flag to force the retry 519 520 *bits |= 0x00000001; 521 522 do { 523 do_trans_retry = false; 524 525 if (is_exiting()) { 526 // Thread is in the process of exiting. This is always checked 527 // first to reduce the risk of dereferencing a freed JavaThread. 528 *bits |= 0x00000100; 529 return false; 530 } 531 532 if (!is_external_suspend()) { 533 // Suspend request is cancelled. This is always checked before 534 // is_ext_suspended() to reduce the risk of a rogue resume 535 // confusing the thread that made the suspend request. 536 *bits |= 0x00000200; 537 return false; 538 } 539 540 if (is_ext_suspended()) { 541 // thread is suspended 542 *bits |= 0x00000400; 543 return true; 544 } 545 546 // Now that we no longer do hard suspends of threads running 547 // native code, the target thread can be changing thread state 548 // while we are in this routine: 549 // 550 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 551 // 552 // We save a copy of the thread state as observed at this moment 553 // and make our decision about suspend completeness based on the 554 // copy. This closes the race where the thread state is seen as 555 // _thread_in_native_trans in the if-thread_blocked check, but is 556 // seen as _thread_blocked in if-thread_in_native_trans check. 557 JavaThreadState save_state = thread_state(); 558 559 if (save_state == _thread_blocked && is_suspend_equivalent()) { 560 // If the thread's state is _thread_blocked and this blocking 561 // condition is known to be equivalent to a suspend, then we can 562 // consider the thread to be externally suspended. This means that 563 // the code that sets _thread_blocked has been modified to do 564 // self-suspension if the blocking condition releases. We also 565 // used to check for CONDVAR_WAIT here, but that is now covered by 566 // the _thread_blocked with self-suspension check. 567 // 568 // Return true since we wouldn't be here unless there was still an 569 // external suspend request. 570 *bits |= 0x00001000; 571 return true; 572 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 573 // Threads running native code will self-suspend on native==>VM/Java 574 // transitions. If its stack is walkable (should always be the case 575 // unless this function is called before the actual java_suspend() 576 // call), then the wait is done. 577 *bits |= 0x00002000; 578 return true; 579 } else if (!called_by_wait && !did_trans_retry && 580 save_state == _thread_in_native_trans && 581 frame_anchor()->walkable()) { 582 // The thread is transitioning from thread_in_native to another 583 // thread state. check_safepoint_and_suspend_for_native_trans() 584 // will force the thread to self-suspend. If it hasn't gotten 585 // there yet we may have caught the thread in-between the native 586 // code check above and the self-suspend. Lucky us. If we were 587 // called by wait_for_ext_suspend_completion(), then it 588 // will be doing the retries so we don't have to. 589 // 590 // Since we use the saved thread state in the if-statement above, 591 // there is a chance that the thread has already transitioned to 592 // _thread_blocked by the time we get here. In that case, we will 593 // make a single unnecessary pass through the logic below. This 594 // doesn't hurt anything since we still do the trans retry. 595 596 *bits |= 0x00004000; 597 598 // Once the thread leaves thread_in_native_trans for another 599 // thread state, we break out of this retry loop. We shouldn't 600 // need this flag to prevent us from getting back here, but 601 // sometimes paranoia is good. 602 did_trans_retry = true; 603 604 // We wait for the thread to transition to a more usable state. 605 for (int i = 1; i <= SuspendRetryCount; i++) { 606 // We used to do an "os::yield_all(i)" call here with the intention 607 // that yielding would increase on each retry. However, the parameter 608 // is ignored on Linux which means the yield didn't scale up. Waiting 609 // on the SR_lock below provides a much more predictable scale up for 610 // the delay. It also provides a simple/direct point to check for any 611 // safepoint requests from the VMThread 612 613 // temporarily drops SR_lock while doing wait with safepoint check 614 // (if we're a JavaThread - the WatcherThread can also call this) 615 // and increase delay with each retry 616 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 617 618 // check the actual thread state instead of what we saved above 619 if (thread_state() != _thread_in_native_trans) { 620 // the thread has transitioned to another thread state so 621 // try all the checks (except this one) one more time. 622 do_trans_retry = true; 623 break; 624 } 625 } // end retry loop 626 627 628 } 629 } while (do_trans_retry); 630 631 *bits |= 0x00000010; 632 return false; 633 } 634 635 // Wait for an external suspend request to complete (or be cancelled). 636 // Returns true if the thread is externally suspended and false otherwise. 637 // 638 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 639 uint32_t *bits) { 640 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 641 false /* !called_by_wait */, bits); 642 643 // local flag copies to minimize SR_lock hold time 644 bool is_suspended; 645 bool pending; 646 uint32_t reset_bits; 647 648 // set a marker so is_ext_suspend_completed() knows we are the caller 649 *bits |= 0x00010000; 650 651 // We use reset_bits to reinitialize the bits value at the top of 652 // each retry loop. This allows the caller to make use of any 653 // unused bits for their own marking purposes. 654 reset_bits = *bits; 655 656 { 657 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 658 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 659 delay, bits); 660 pending = is_external_suspend(); 661 } 662 // must release SR_lock to allow suspension to complete 663 664 if (!pending) { 665 // A cancelled suspend request is the only false return from 666 // is_ext_suspend_completed() that keeps us from entering the 667 // retry loop. 668 *bits |= 0x00020000; 669 return false; 670 } 671 672 if (is_suspended) { 673 *bits |= 0x00040000; 674 return true; 675 } 676 677 for (int i = 1; i <= retries; i++) { 678 *bits = reset_bits; // reinit to only track last retry 679 680 // We used to do an "os::yield_all(i)" call here with the intention 681 // that yielding would increase on each retry. However, the parameter 682 // is ignored on Linux which means the yield didn't scale up. Waiting 683 // on the SR_lock below provides a much more predictable scale up for 684 // the delay. It also provides a simple/direct point to check for any 685 // safepoint requests from the VMThread 686 687 { 688 MutexLocker ml(SR_lock()); 689 // wait with safepoint check (if we're a JavaThread - the WatcherThread 690 // can also call this) and increase delay with each retry 691 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 692 693 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 694 delay, bits); 695 696 // It is possible for the external suspend request to be cancelled 697 // (by a resume) before the actual suspend operation is completed. 698 // Refresh our local copy to see if we still need to wait. 699 pending = is_external_suspend(); 700 } 701 702 if (!pending) { 703 // A cancelled suspend request is the only false return from 704 // is_ext_suspend_completed() that keeps us from staying in the 705 // retry loop. 706 *bits |= 0x00080000; 707 return false; 708 } 709 710 if (is_suspended) { 711 *bits |= 0x00100000; 712 return true; 713 } 714 } // end retry loop 715 716 // thread did not suspend after all our retries 717 *bits |= 0x00200000; 718 return false; 719 } 720 721 #ifndef PRODUCT 722 void JavaThread::record_jump(address target, address instr, const char* file, 723 int line) { 724 725 // This should not need to be atomic as the only way for simultaneous 726 // updates is via interrupts. Even then this should be rare or non-existent 727 // and we don't care that much anyway. 728 729 int index = _jmp_ring_index; 730 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 731 _jmp_ring[index]._target = (intptr_t) target; 732 _jmp_ring[index]._instruction = (intptr_t) instr; 733 _jmp_ring[index]._file = file; 734 _jmp_ring[index]._line = line; 735 } 736 #endif // PRODUCT 737 738 // Called by flat profiler 739 // Callers have already called wait_for_ext_suspend_completion 740 // The assertion for that is currently too complex to put here: 741 bool JavaThread::profile_last_Java_frame(frame* _fr) { 742 bool gotframe = false; 743 // self suspension saves needed state. 744 if (has_last_Java_frame() && _anchor.walkable()) { 745 *_fr = pd_last_frame(); 746 gotframe = true; 747 } 748 return gotframe; 749 } 750 751 void Thread::interrupt(Thread* thread) { 752 debug_only(check_for_dangling_thread_pointer(thread);) 753 os::interrupt(thread); 754 } 755 756 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 757 debug_only(check_for_dangling_thread_pointer(thread);) 758 // Note: If clear_interrupted==false, this simply fetches and 759 // returns the value of the field osthread()->interrupted(). 760 return os::is_interrupted(thread, clear_interrupted); 761 } 762 763 764 // GC Support 765 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 766 jint thread_parity = _oops_do_parity; 767 if (thread_parity != strong_roots_parity) { 768 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 769 if (res == thread_parity) { 770 return true; 771 } else { 772 guarantee(res == strong_roots_parity, "Or else what?"); 773 return false; 774 } 775 } 776 return false; 777 } 778 779 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 780 active_handles()->oops_do(f); 781 // Do oop for ThreadShadow 782 f->do_oop((oop*)&_pending_exception); 783 handle_area()->oops_do(f); 784 } 785 786 void Thread::nmethods_do(CodeBlobClosure* cf) { 787 // no nmethods in a generic thread... 788 } 789 790 void Thread::metadata_handles_do(void f(Metadata*)) { 791 // Only walk the Handles in Thread. 792 if (metadata_handles() != NULL) { 793 for (int i = 0; i< metadata_handles()->length(); i++) { 794 f(metadata_handles()->at(i)); 795 } 796 } 797 } 798 799 void Thread::print_on(outputStream* st) const { 800 // get_priority assumes osthread initialized 801 if (osthread() != NULL) { 802 int os_prio; 803 if (os::get_native_priority(this, &os_prio) == OS_OK) { 804 st->print("os_prio=%d ", os_prio); 805 } 806 st->print("tid=" INTPTR_FORMAT " ", p2i(this)); 807 ext().print_on(st); 808 osthread()->print_on(st); 809 } 810 debug_only(if (WizardMode) print_owned_locks_on(st);) 811 } 812 813 // Thread::print_on_error() is called by fatal error handler. Don't use 814 // any lock or allocate memory. 815 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 816 if (is_VM_thread()) st->print("VMThread"); 817 else if (is_Compiler_thread()) st->print("CompilerThread"); 818 else if (is_Java_thread()) st->print("JavaThread"); 819 else if (is_GC_task_thread()) st->print("GCTaskThread"); 820 else if (is_Watcher_thread()) st->print("WatcherThread"); 821 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 822 else st->print("Thread"); 823 824 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 825 p2i(stack_end()), p2i(stack_base())); 826 827 if (osthread()) { 828 st->print(" [id=%d]", osthread()->thread_id()); 829 } 830 } 831 832 #ifdef ASSERT 833 void Thread::print_owned_locks_on(outputStream* st) const { 834 Monitor *cur = _owned_locks; 835 if (cur == NULL) { 836 st->print(" (no locks) "); 837 } else { 838 st->print_cr(" Locks owned:"); 839 while (cur) { 840 cur->print_on(st); 841 cur = cur->next(); 842 } 843 } 844 } 845 846 static int ref_use_count = 0; 847 848 bool Thread::owns_locks_but_compiled_lock() const { 849 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 850 if (cur != Compile_lock) return true; 851 } 852 return false; 853 } 854 855 856 #endif 857 858 #ifndef PRODUCT 859 860 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 861 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 862 // no threads which allow_vm_block's are held 863 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 864 // Check if current thread is allowed to block at a safepoint 865 if (!(_allow_safepoint_count == 0)) { 866 fatal("Possible safepoint reached by thread that does not allow it"); 867 } 868 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 869 fatal("LEAF method calling lock?"); 870 } 871 872 #ifdef ASSERT 873 if (potential_vm_operation && is_Java_thread() 874 && !Universe::is_bootstrapping()) { 875 // Make sure we do not hold any locks that the VM thread also uses. 876 // This could potentially lead to deadlocks 877 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 878 // Threads_lock is special, since the safepoint synchronization will not start before this is 879 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 880 // since it is used to transfer control between JavaThreads and the VMThread 881 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 882 if ((cur->allow_vm_block() && 883 cur != Threads_lock && 884 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 885 cur != VMOperationRequest_lock && 886 cur != VMOperationQueue_lock) || 887 cur->rank() == Mutex::special) { 888 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 889 } 890 } 891 } 892 893 if (GCALotAtAllSafepoints) { 894 // We could enter a safepoint here and thus have a gc 895 InterfaceSupport::check_gc_alot(); 896 } 897 #endif 898 } 899 #endif 900 901 bool Thread::is_in_stack(address adr) const { 902 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 903 address end = os::current_stack_pointer(); 904 // Allow non Java threads to call this without stack_base 905 if (_stack_base == NULL) return true; 906 if (stack_base() >= adr && adr >= end) return true; 907 908 return false; 909 } 910 911 bool Thread::is_in_usable_stack(address adr) const { 912 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0; 913 size_t usable_stack_size = _stack_size - stack_guard_size; 914 915 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 916 } 917 918 919 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 920 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 921 // used for compilation in the future. If that change is made, the need for these methods 922 // should be revisited, and they should be removed if possible. 923 924 bool Thread::is_lock_owned(address adr) const { 925 return on_local_stack(adr); 926 } 927 928 bool Thread::set_as_starting_thread() { 929 // NOTE: this must be called inside the main thread. 930 return os::create_main_thread((JavaThread*)this); 931 } 932 933 static void initialize_class(Symbol* class_name, TRAPS) { 934 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 935 InstanceKlass::cast(klass)->initialize(CHECK); 936 } 937 938 939 // Creates the initial ThreadGroup 940 static Handle create_initial_thread_group(TRAPS) { 941 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 942 instanceKlassHandle klass (THREAD, k); 943 944 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 945 { 946 JavaValue result(T_VOID); 947 JavaCalls::call_special(&result, 948 system_instance, 949 klass, 950 vmSymbols::object_initializer_name(), 951 vmSymbols::void_method_signature(), 952 CHECK_NH); 953 } 954 Universe::set_system_thread_group(system_instance()); 955 956 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 957 { 958 JavaValue result(T_VOID); 959 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 960 JavaCalls::call_special(&result, 961 main_instance, 962 klass, 963 vmSymbols::object_initializer_name(), 964 vmSymbols::threadgroup_string_void_signature(), 965 system_instance, 966 string, 967 CHECK_NH); 968 } 969 return main_instance; 970 } 971 972 // Creates the initial Thread 973 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 974 TRAPS) { 975 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 976 instanceKlassHandle klass (THREAD, k); 977 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 978 979 java_lang_Thread::set_thread(thread_oop(), thread); 980 java_lang_Thread::set_priority(thread_oop(), NormPriority); 981 thread->set_threadObj(thread_oop()); 982 983 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 984 985 JavaValue result(T_VOID); 986 JavaCalls::call_special(&result, thread_oop, 987 klass, 988 vmSymbols::object_initializer_name(), 989 vmSymbols::threadgroup_string_void_signature(), 990 thread_group, 991 string, 992 CHECK_NULL); 993 return thread_oop(); 994 } 995 996 static void call_initializeSystemClass(TRAPS) { 997 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 998 instanceKlassHandle klass (THREAD, k); 999 1000 JavaValue result(T_VOID); 1001 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1002 vmSymbols::void_method_signature(), CHECK); 1003 } 1004 1005 char java_runtime_name[128] = ""; 1006 char java_runtime_version[128] = ""; 1007 1008 // extract the JRE name from sun.misc.Version.java_runtime_name 1009 static const char* get_java_runtime_name(TRAPS) { 1010 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1011 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1012 fieldDescriptor fd; 1013 bool found = k != NULL && 1014 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1015 vmSymbols::string_signature(), &fd); 1016 if (found) { 1017 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1018 if (name_oop == NULL) { 1019 return NULL; 1020 } 1021 const char* name = java_lang_String::as_utf8_string(name_oop, 1022 java_runtime_name, 1023 sizeof(java_runtime_name)); 1024 return name; 1025 } else { 1026 return NULL; 1027 } 1028 } 1029 1030 // extract the JRE version from sun.misc.Version.java_runtime_version 1031 static const char* get_java_runtime_version(TRAPS) { 1032 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1033 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1034 fieldDescriptor fd; 1035 bool found = k != NULL && 1036 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1037 vmSymbols::string_signature(), &fd); 1038 if (found) { 1039 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1040 if (name_oop == NULL) { 1041 return NULL; 1042 } 1043 const char* name = java_lang_String::as_utf8_string(name_oop, 1044 java_runtime_version, 1045 sizeof(java_runtime_version)); 1046 return name; 1047 } else { 1048 return NULL; 1049 } 1050 } 1051 1052 // General purpose hook into Java code, run once when the VM is initialized. 1053 // The Java library method itself may be changed independently from the VM. 1054 static void call_postVMInitHook(TRAPS) { 1055 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1056 instanceKlassHandle klass (THREAD, k); 1057 if (klass.not_null()) { 1058 JavaValue result(T_VOID); 1059 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1060 vmSymbols::void_method_signature(), 1061 CHECK); 1062 } 1063 } 1064 1065 static void reset_vm_info_property(TRAPS) { 1066 // the vm info string 1067 ResourceMark rm(THREAD); 1068 const char *vm_info = VM_Version::vm_info_string(); 1069 1070 // java.lang.System class 1071 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1072 instanceKlassHandle klass (THREAD, k); 1073 1074 // setProperty arguments 1075 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1076 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1077 1078 // return value 1079 JavaValue r(T_OBJECT); 1080 1081 // public static String setProperty(String key, String value); 1082 JavaCalls::call_static(&r, 1083 klass, 1084 vmSymbols::setProperty_name(), 1085 vmSymbols::string_string_string_signature(), 1086 key_str, 1087 value_str, 1088 CHECK); 1089 } 1090 1091 1092 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 1093 bool daemon, TRAPS) { 1094 assert(thread_group.not_null(), "thread group should be specified"); 1095 assert(threadObj() == NULL, "should only create Java thread object once"); 1096 1097 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1098 instanceKlassHandle klass (THREAD, k); 1099 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1100 1101 java_lang_Thread::set_thread(thread_oop(), this); 1102 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1103 set_threadObj(thread_oop()); 1104 1105 JavaValue result(T_VOID); 1106 if (thread_name != NULL) { 1107 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1108 // Thread gets assigned specified name and null target 1109 JavaCalls::call_special(&result, 1110 thread_oop, 1111 klass, 1112 vmSymbols::object_initializer_name(), 1113 vmSymbols::threadgroup_string_void_signature(), 1114 thread_group, // Argument 1 1115 name, // Argument 2 1116 THREAD); 1117 } else { 1118 // Thread gets assigned name "Thread-nnn" and null target 1119 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1120 JavaCalls::call_special(&result, 1121 thread_oop, 1122 klass, 1123 vmSymbols::object_initializer_name(), 1124 vmSymbols::threadgroup_runnable_void_signature(), 1125 thread_group, // Argument 1 1126 Handle(), // Argument 2 1127 THREAD); 1128 } 1129 1130 1131 if (daemon) { 1132 java_lang_Thread::set_daemon(thread_oop()); 1133 } 1134 1135 if (HAS_PENDING_EXCEPTION) { 1136 return; 1137 } 1138 1139 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass()); 1140 Handle threadObj(THREAD, this->threadObj()); 1141 1142 JavaCalls::call_special(&result, 1143 thread_group, 1144 group, 1145 vmSymbols::add_method_name(), 1146 vmSymbols::thread_void_signature(), 1147 threadObj, // Arg 1 1148 THREAD); 1149 } 1150 1151 // NamedThread -- non-JavaThread subclasses with multiple 1152 // uniquely named instances should derive from this. 1153 NamedThread::NamedThread() : Thread() { 1154 _name = NULL; 1155 _processed_thread = NULL; 1156 _gc_id = GCId::undefined(); 1157 } 1158 1159 NamedThread::~NamedThread() { 1160 if (_name != NULL) { 1161 FREE_C_HEAP_ARRAY(char, _name); 1162 _name = NULL; 1163 } 1164 } 1165 1166 void NamedThread::set_name(const char* format, ...) { 1167 guarantee(_name == NULL, "Only get to set name once."); 1168 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1169 guarantee(_name != NULL, "alloc failure"); 1170 va_list ap; 1171 va_start(ap, format); 1172 jio_vsnprintf(_name, max_name_len, format, ap); 1173 va_end(ap); 1174 } 1175 1176 void NamedThread::initialize_named_thread() { 1177 set_native_thread_name(name()); 1178 } 1179 1180 void NamedThread::print_on(outputStream* st) const { 1181 st->print("\"%s\" ", name()); 1182 Thread::print_on(st); 1183 st->cr(); 1184 } 1185 1186 1187 // ======= WatcherThread ======== 1188 1189 // The watcher thread exists to simulate timer interrupts. It should 1190 // be replaced by an abstraction over whatever native support for 1191 // timer interrupts exists on the platform. 1192 1193 WatcherThread* WatcherThread::_watcher_thread = NULL; 1194 bool WatcherThread::_startable = false; 1195 volatile bool WatcherThread::_should_terminate = false; 1196 1197 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1198 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1199 if (os::create_thread(this, os::watcher_thread)) { 1200 _watcher_thread = this; 1201 1202 // Set the watcher thread to the highest OS priority which should not be 1203 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1204 // is created. The only normal thread using this priority is the reference 1205 // handler thread, which runs for very short intervals only. 1206 // If the VMThread's priority is not lower than the WatcherThread profiling 1207 // will be inaccurate. 1208 os::set_priority(this, MaxPriority); 1209 if (!DisableStartThread) { 1210 os::start_thread(this); 1211 } 1212 } 1213 } 1214 1215 int WatcherThread::sleep() const { 1216 // The WatcherThread does not participate in the safepoint protocol 1217 // for the PeriodicTask_lock because it is not a JavaThread. 1218 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1219 1220 if (_should_terminate) { 1221 // check for termination before we do any housekeeping or wait 1222 return 0; // we did not sleep. 1223 } 1224 1225 // remaining will be zero if there are no tasks, 1226 // causing the WatcherThread to sleep until a task is 1227 // enrolled 1228 int remaining = PeriodicTask::time_to_wait(); 1229 int time_slept = 0; 1230 1231 // we expect this to timeout - we only ever get unparked when 1232 // we should terminate or when a new task has been enrolled 1233 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1234 1235 jlong time_before_loop = os::javaTimeNanos(); 1236 1237 while (true) { 1238 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, 1239 remaining); 1240 jlong now = os::javaTimeNanos(); 1241 1242 if (remaining == 0) { 1243 // if we didn't have any tasks we could have waited for a long time 1244 // consider the time_slept zero and reset time_before_loop 1245 time_slept = 0; 1246 time_before_loop = now; 1247 } else { 1248 // need to recalculate since we might have new tasks in _tasks 1249 time_slept = (int) ((now - time_before_loop) / 1000000); 1250 } 1251 1252 // Change to task list or spurious wakeup of some kind 1253 if (timedout || _should_terminate) { 1254 break; 1255 } 1256 1257 remaining = PeriodicTask::time_to_wait(); 1258 if (remaining == 0) { 1259 // Last task was just disenrolled so loop around and wait until 1260 // another task gets enrolled 1261 continue; 1262 } 1263 1264 remaining -= time_slept; 1265 if (remaining <= 0) { 1266 break; 1267 } 1268 } 1269 1270 return time_slept; 1271 } 1272 1273 void WatcherThread::run() { 1274 assert(this == watcher_thread(), "just checking"); 1275 1276 this->record_stack_base_and_size(); 1277 this->set_native_thread_name(this->name()); 1278 this->set_active_handles(JNIHandleBlock::allocate_block()); 1279 while (true) { 1280 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1281 assert(watcher_thread() == this, "thread consistency check"); 1282 1283 // Calculate how long it'll be until the next PeriodicTask work 1284 // should be done, and sleep that amount of time. 1285 int time_waited = sleep(); 1286 1287 if (is_error_reported()) { 1288 // A fatal error has happened, the error handler(VMError::report_and_die) 1289 // should abort JVM after creating an error log file. However in some 1290 // rare cases, the error handler itself might deadlock. Here we try to 1291 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1292 // 1293 // This code is in WatcherThread because WatcherThread wakes up 1294 // periodically so the fatal error handler doesn't need to do anything; 1295 // also because the WatcherThread is less likely to crash than other 1296 // threads. 1297 1298 for (;;) { 1299 if (!ShowMessageBoxOnError 1300 && (OnError == NULL || OnError[0] == '\0') 1301 && Arguments::abort_hook() == NULL) { 1302 os::sleep(this, (jlong)ErrorLogTimeout * 1000, false); // in seconds 1303 fdStream err(defaultStream::output_fd()); 1304 err.print_raw_cr("# [ timer expired, abort... ]"); 1305 // skip atexit/vm_exit/vm_abort hooks 1306 os::die(); 1307 } 1308 1309 // Wake up 5 seconds later, the fatal handler may reset OnError or 1310 // ShowMessageBoxOnError when it is ready to abort. 1311 os::sleep(this, 5 * 1000, false); 1312 } 1313 } 1314 1315 if (_should_terminate) { 1316 // check for termination before posting the next tick 1317 break; 1318 } 1319 1320 PeriodicTask::real_time_tick(time_waited); 1321 } 1322 1323 // Signal that it is terminated 1324 { 1325 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1326 _watcher_thread = NULL; 1327 Terminator_lock->notify(); 1328 } 1329 } 1330 1331 void WatcherThread::start() { 1332 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1333 1334 if (watcher_thread() == NULL && _startable) { 1335 _should_terminate = false; 1336 // Create the single instance of WatcherThread 1337 new WatcherThread(); 1338 } 1339 } 1340 1341 void WatcherThread::make_startable() { 1342 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1343 _startable = true; 1344 } 1345 1346 void WatcherThread::stop() { 1347 { 1348 // Follow normal safepoint aware lock enter protocol since the 1349 // WatcherThread is stopped by another JavaThread. 1350 MutexLocker ml(PeriodicTask_lock); 1351 _should_terminate = true; 1352 1353 WatcherThread* watcher = watcher_thread(); 1354 if (watcher != NULL) { 1355 // unpark the WatcherThread so it can see that it should terminate 1356 watcher->unpark(); 1357 } 1358 } 1359 1360 MutexLocker mu(Terminator_lock); 1361 1362 while (watcher_thread() != NULL) { 1363 // This wait should make safepoint checks, wait without a timeout, 1364 // and wait as a suspend-equivalent condition. 1365 // 1366 // Note: If the FlatProfiler is running, then this thread is waiting 1367 // for the WatcherThread to terminate and the WatcherThread, via the 1368 // FlatProfiler task, is waiting for the external suspend request on 1369 // this thread to complete. wait_for_ext_suspend_completion() will 1370 // eventually timeout, but that takes time. Making this wait a 1371 // suspend-equivalent condition solves that timeout problem. 1372 // 1373 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1374 Mutex::_as_suspend_equivalent_flag); 1375 } 1376 } 1377 1378 void WatcherThread::unpark() { 1379 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1380 PeriodicTask_lock->notify(); 1381 } 1382 1383 void WatcherThread::print_on(outputStream* st) const { 1384 st->print("\"%s\" ", name()); 1385 Thread::print_on(st); 1386 st->cr(); 1387 } 1388 1389 // ======= JavaThread ======== 1390 1391 #if INCLUDE_JVMCI 1392 1393 jlong* JavaThread::_jvmci_old_thread_counters; 1394 1395 bool jvmci_counters_include(JavaThread* thread) { 1396 oop threadObj = thread->threadObj(); 1397 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); 1398 } 1399 1400 void JavaThread::collect_counters(typeArrayOop array) { 1401 if (JVMCICounterSize > 0) { 1402 MutexLocker tl(Threads_lock); 1403 for (int i = 0; i < array->length(); i++) { 1404 array->long_at_put(i, _jvmci_old_thread_counters[i]); 1405 } 1406 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) { 1407 if (jvmci_counters_include(tp)) { 1408 for (int i = 0; i < array->length(); i++) { 1409 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]); 1410 } 1411 } 1412 } 1413 } 1414 } 1415 1416 #endif // INCLUDE_JVMCI 1417 1418 // A JavaThread is a normal Java thread 1419 1420 void JavaThread::initialize() { 1421 // Initialize fields 1422 1423 set_saved_exception_pc(NULL); 1424 set_threadObj(NULL); 1425 _anchor.clear(); 1426 set_entry_point(NULL); 1427 set_jni_functions(jni_functions()); 1428 set_callee_target(NULL); 1429 set_vm_result(NULL); 1430 set_vm_result_2(NULL); 1431 set_vframe_array_head(NULL); 1432 set_vframe_array_last(NULL); 1433 set_deferred_locals(NULL); 1434 set_deopt_mark(NULL); 1435 set_deopt_nmethod(NULL); 1436 clear_must_deopt_id(); 1437 set_monitor_chunks(NULL); 1438 set_next(NULL); 1439 set_thread_state(_thread_new); 1440 _terminated = _not_terminated; 1441 _privileged_stack_top = NULL; 1442 _array_for_gc = NULL; 1443 _suspend_equivalent = false; 1444 _in_deopt_handler = 0; 1445 _doing_unsafe_access = false; 1446 _stack_guard_state = stack_guard_unused; 1447 #if INCLUDE_JVMCI 1448 _pending_monitorenter = false; 1449 _pending_deoptimization = -1; 1450 _pending_failed_speculation = NULL; 1451 _pending_transfer_to_interpreter = false; 1452 _jvmci._alternate_call_target = NULL; 1453 assert(_jvmci._implicit_exception_pc == NULL, "must be"); 1454 if (JVMCICounterSize > 0) { 1455 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 1456 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize); 1457 } else { 1458 _jvmci_counters = NULL; 1459 } 1460 #endif // INCLUDE_JVMCI 1461 _reserved_stack_activation = NULL; // stack base not known yet 1462 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1463 _exception_pc = 0; 1464 _exception_handler_pc = 0; 1465 _is_method_handle_return = 0; 1466 _jvmti_thread_state= NULL; 1467 _should_post_on_exceptions_flag = JNI_FALSE; 1468 _jvmti_get_loaded_classes_closure = NULL; 1469 _interp_only_mode = 0; 1470 _special_runtime_exit_condition = _no_async_condition; 1471 _pending_async_exception = NULL; 1472 _thread_stat = NULL; 1473 _thread_stat = new ThreadStatistics(); 1474 _blocked_on_compilation = false; 1475 _jni_active_critical = 0; 1476 _pending_jni_exception_check_fn = NULL; 1477 _do_not_unlock_if_synchronized = false; 1478 _cached_monitor_info = NULL; 1479 _parker = Parker::Allocate(this); 1480 1481 #ifndef PRODUCT 1482 _jmp_ring_index = 0; 1483 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1484 record_jump(NULL, NULL, NULL, 0); 1485 } 1486 #endif // PRODUCT 1487 1488 set_thread_profiler(NULL); 1489 if (FlatProfiler::is_active()) { 1490 // This is where we would decide to either give each thread it's own profiler 1491 // or use one global one from FlatProfiler, 1492 // or up to some count of the number of profiled threads, etc. 1493 ThreadProfiler* pp = new ThreadProfiler(); 1494 pp->engage(); 1495 set_thread_profiler(pp); 1496 } 1497 1498 // Setup safepoint state info for this thread 1499 ThreadSafepointState::create(this); 1500 1501 debug_only(_java_call_counter = 0); 1502 1503 // JVMTI PopFrame support 1504 _popframe_condition = popframe_inactive; 1505 _popframe_preserved_args = NULL; 1506 _popframe_preserved_args_size = 0; 1507 _frames_to_pop_failed_realloc = 0; 1508 1509 pd_initialize(); 1510 } 1511 1512 #if INCLUDE_ALL_GCS 1513 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1514 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1515 #endif // INCLUDE_ALL_GCS 1516 1517 JavaThread::JavaThread(bool is_attaching_via_jni) : 1518 Thread() 1519 #if INCLUDE_ALL_GCS 1520 , _satb_mark_queue(&_satb_mark_queue_set), 1521 _dirty_card_queue(&_dirty_card_queue_set) 1522 #endif // INCLUDE_ALL_GCS 1523 { 1524 initialize(); 1525 if (is_attaching_via_jni) { 1526 _jni_attach_state = _attaching_via_jni; 1527 } else { 1528 _jni_attach_state = _not_attaching_via_jni; 1529 } 1530 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1531 } 1532 1533 bool JavaThread::reguard_stack(address cur_sp) { 1534 if (_stack_guard_state != stack_guard_yellow_reserved_disabled 1535 && _stack_guard_state != stack_guard_reserved_disabled) { 1536 return true; // Stack already guarded or guard pages not needed. 1537 } 1538 1539 if (register_stack_overflow()) { 1540 // For those architectures which have separate register and 1541 // memory stacks, we must check the register stack to see if 1542 // it has overflowed. 1543 return false; 1544 } 1545 1546 // Java code never executes within the yellow zone: the latter is only 1547 // there to provoke an exception during stack banging. If java code 1548 // is executing there, either StackShadowPages should be larger, or 1549 // some exception code in c1, c2 or the interpreter isn't unwinding 1550 // when it should. 1551 guarantee(cur_sp > stack_reserved_zone_base(), 1552 "not enough space to reguard - increase StackShadowPages"); 1553 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) { 1554 enable_stack_yellow_reserved_zone(); 1555 if (reserved_stack_activation() != stack_base()) { 1556 set_reserved_stack_activation(stack_base()); 1557 } 1558 } else if (_stack_guard_state == stack_guard_reserved_disabled) { 1559 set_reserved_stack_activation(stack_base()); 1560 enable_stack_reserved_zone(); 1561 } 1562 return true; 1563 } 1564 1565 bool JavaThread::reguard_stack(void) { 1566 return reguard_stack(os::current_stack_pointer()); 1567 } 1568 1569 1570 void JavaThread::block_if_vm_exited() { 1571 if (_terminated == _vm_exited) { 1572 // _vm_exited is set at safepoint, and Threads_lock is never released 1573 // we will block here forever 1574 Threads_lock->lock_without_safepoint_check(); 1575 ShouldNotReachHere(); 1576 } 1577 } 1578 1579 1580 // Remove this ifdef when C1 is ported to the compiler interface. 1581 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1582 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1583 1584 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1585 Thread() 1586 #if INCLUDE_ALL_GCS 1587 , _satb_mark_queue(&_satb_mark_queue_set), 1588 _dirty_card_queue(&_dirty_card_queue_set) 1589 #endif // INCLUDE_ALL_GCS 1590 { 1591 initialize(); 1592 _jni_attach_state = _not_attaching_via_jni; 1593 set_entry_point(entry_point); 1594 // Create the native thread itself. 1595 // %note runtime_23 1596 os::ThreadType thr_type = os::java_thread; 1597 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1598 os::java_thread; 1599 os::create_thread(this, thr_type, stack_sz); 1600 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1601 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1602 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1603 // the exception consists of creating the exception object & initializing it, initialization 1604 // will leave the VM via a JavaCall and then all locks must be unlocked). 1605 // 1606 // The thread is still suspended when we reach here. Thread must be explicit started 1607 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1608 // by calling Threads:add. The reason why this is not done here, is because the thread 1609 // object must be fully initialized (take a look at JVM_Start) 1610 } 1611 1612 JavaThread::~JavaThread() { 1613 1614 // JSR166 -- return the parker to the free list 1615 Parker::Release(_parker); 1616 _parker = NULL; 1617 1618 // Free any remaining previous UnrollBlock 1619 vframeArray* old_array = vframe_array_last(); 1620 1621 if (old_array != NULL) { 1622 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1623 old_array->set_unroll_block(NULL); 1624 delete old_info; 1625 delete old_array; 1626 } 1627 1628 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1629 if (deferred != NULL) { 1630 // This can only happen if thread is destroyed before deoptimization occurs. 1631 assert(deferred->length() != 0, "empty array!"); 1632 do { 1633 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1634 deferred->remove_at(0); 1635 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1636 delete dlv; 1637 } while (deferred->length() != 0); 1638 delete deferred; 1639 } 1640 1641 // All Java related clean up happens in exit 1642 ThreadSafepointState::destroy(this); 1643 if (_thread_profiler != NULL) delete _thread_profiler; 1644 if (_thread_stat != NULL) delete _thread_stat; 1645 1646 #if INCLUDE_JVMCI 1647 if (JVMCICounterSize > 0) { 1648 if (jvmci_counters_include(this)) { 1649 for (int i = 0; i < JVMCICounterSize; i++) { 1650 _jvmci_old_thread_counters[i] += _jvmci_counters[i]; 1651 } 1652 } 1653 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); 1654 } 1655 #endif // INCLUDE_JVMCI 1656 } 1657 1658 1659 // The first routine called by a new Java thread 1660 void JavaThread::run() { 1661 // initialize thread-local alloc buffer related fields 1662 this->initialize_tlab(); 1663 1664 // used to test validity of stack trace backs 1665 this->record_base_of_stack_pointer(); 1666 1667 // Record real stack base and size. 1668 this->record_stack_base_and_size(); 1669 1670 this->create_stack_guard_pages(); 1671 1672 this->cache_global_variables(); 1673 1674 // Thread is now sufficient initialized to be handled by the safepoint code as being 1675 // in the VM. Change thread state from _thread_new to _thread_in_vm 1676 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1677 1678 assert(JavaThread::current() == this, "sanity check"); 1679 assert(!Thread::current()->owns_locks(), "sanity check"); 1680 1681 DTRACE_THREAD_PROBE(start, this); 1682 1683 // This operation might block. We call that after all safepoint checks for a new thread has 1684 // been completed. 1685 this->set_active_handles(JNIHandleBlock::allocate_block()); 1686 1687 if (JvmtiExport::should_post_thread_life()) { 1688 JvmtiExport::post_thread_start(this); 1689 } 1690 1691 EventThreadStart event; 1692 if (event.should_commit()) { 1693 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1694 event.commit(); 1695 } 1696 1697 // We call another function to do the rest so we are sure that the stack addresses used 1698 // from there will be lower than the stack base just computed 1699 thread_main_inner(); 1700 1701 // Note, thread is no longer valid at this point! 1702 } 1703 1704 1705 void JavaThread::thread_main_inner() { 1706 assert(JavaThread::current() == this, "sanity check"); 1707 assert(this->threadObj() != NULL, "just checking"); 1708 1709 // Execute thread entry point unless this thread has a pending exception 1710 // or has been stopped before starting. 1711 // Note: Due to JVM_StopThread we can have pending exceptions already! 1712 if (!this->has_pending_exception() && 1713 !java_lang_Thread::is_stillborn(this->threadObj())) { 1714 { 1715 ResourceMark rm(this); 1716 this->set_native_thread_name(this->get_thread_name()); 1717 } 1718 HandleMark hm(this); 1719 this->entry_point()(this, this); 1720 } 1721 1722 DTRACE_THREAD_PROBE(stop, this); 1723 1724 this->exit(false); 1725 delete this; 1726 } 1727 1728 1729 static void ensure_join(JavaThread* thread) { 1730 // We do not need to grap the Threads_lock, since we are operating on ourself. 1731 Handle threadObj(thread, thread->threadObj()); 1732 assert(threadObj.not_null(), "java thread object must exist"); 1733 ObjectLocker lock(threadObj, thread); 1734 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1735 thread->clear_pending_exception(); 1736 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1737 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1738 // Clear the native thread instance - this makes isAlive return false and allows the join() 1739 // to complete once we've done the notify_all below 1740 java_lang_Thread::set_thread(threadObj(), NULL); 1741 lock.notify_all(thread); 1742 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1743 thread->clear_pending_exception(); 1744 } 1745 1746 1747 // For any new cleanup additions, please check to see if they need to be applied to 1748 // cleanup_failed_attach_current_thread as well. 1749 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1750 assert(this == JavaThread::current(), "thread consistency check"); 1751 1752 HandleMark hm(this); 1753 Handle uncaught_exception(this, this->pending_exception()); 1754 this->clear_pending_exception(); 1755 Handle threadObj(this, this->threadObj()); 1756 assert(threadObj.not_null(), "Java thread object should be created"); 1757 1758 if (get_thread_profiler() != NULL) { 1759 get_thread_profiler()->disengage(); 1760 ResourceMark rm; 1761 get_thread_profiler()->print(get_thread_name()); 1762 } 1763 1764 1765 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1766 { 1767 EXCEPTION_MARK; 1768 1769 CLEAR_PENDING_EXCEPTION; 1770 } 1771 if (!destroy_vm) { 1772 if (uncaught_exception.not_null()) { 1773 EXCEPTION_MARK; 1774 // Call method Thread.dispatchUncaughtException(). 1775 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1776 JavaValue result(T_VOID); 1777 JavaCalls::call_virtual(&result, 1778 threadObj, thread_klass, 1779 vmSymbols::dispatchUncaughtException_name(), 1780 vmSymbols::throwable_void_signature(), 1781 uncaught_exception, 1782 THREAD); 1783 if (HAS_PENDING_EXCEPTION) { 1784 ResourceMark rm(this); 1785 jio_fprintf(defaultStream::error_stream(), 1786 "\nException: %s thrown from the UncaughtExceptionHandler" 1787 " in thread \"%s\"\n", 1788 pending_exception()->klass()->external_name(), 1789 get_thread_name()); 1790 CLEAR_PENDING_EXCEPTION; 1791 } 1792 } 1793 1794 // Called before the java thread exit since we want to read info 1795 // from java_lang_Thread object 1796 EventThreadEnd event; 1797 if (event.should_commit()) { 1798 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1799 event.commit(); 1800 } 1801 1802 // Call after last event on thread 1803 EVENT_THREAD_EXIT(this); 1804 1805 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1806 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1807 // is deprecated anyhow. 1808 if (!is_Compiler_thread()) { 1809 int count = 3; 1810 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1811 EXCEPTION_MARK; 1812 JavaValue result(T_VOID); 1813 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1814 JavaCalls::call_virtual(&result, 1815 threadObj, thread_klass, 1816 vmSymbols::exit_method_name(), 1817 vmSymbols::void_method_signature(), 1818 THREAD); 1819 CLEAR_PENDING_EXCEPTION; 1820 } 1821 } 1822 // notify JVMTI 1823 if (JvmtiExport::should_post_thread_life()) { 1824 JvmtiExport::post_thread_end(this); 1825 } 1826 1827 // We have notified the agents that we are exiting, before we go on, 1828 // we must check for a pending external suspend request and honor it 1829 // in order to not surprise the thread that made the suspend request. 1830 while (true) { 1831 { 1832 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1833 if (!is_external_suspend()) { 1834 set_terminated(_thread_exiting); 1835 ThreadService::current_thread_exiting(this); 1836 break; 1837 } 1838 // Implied else: 1839 // Things get a little tricky here. We have a pending external 1840 // suspend request, but we are holding the SR_lock so we 1841 // can't just self-suspend. So we temporarily drop the lock 1842 // and then self-suspend. 1843 } 1844 1845 ThreadBlockInVM tbivm(this); 1846 java_suspend_self(); 1847 1848 // We're done with this suspend request, but we have to loop around 1849 // and check again. Eventually we will get SR_lock without a pending 1850 // external suspend request and will be able to mark ourselves as 1851 // exiting. 1852 } 1853 // no more external suspends are allowed at this point 1854 } else { 1855 // before_exit() has already posted JVMTI THREAD_END events 1856 } 1857 1858 // Notify waiters on thread object. This has to be done after exit() is called 1859 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1860 // group should have the destroyed bit set before waiters are notified). 1861 ensure_join(this); 1862 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1863 1864 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1865 // held by this thread must be released. The spec does not distinguish 1866 // between JNI-acquired and regular Java monitors. We can only see 1867 // regular Java monitors here if monitor enter-exit matching is broken. 1868 // 1869 // Optionally release any monitors for regular JavaThread exits. This 1870 // is provided as a work around for any bugs in monitor enter-exit 1871 // matching. This can be expensive so it is not enabled by default. 1872 // 1873 // ensure_join() ignores IllegalThreadStateExceptions, and so does 1874 // ObjectSynchronizer::release_monitors_owned_by_thread(). 1875 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) { 1876 // Sanity check even though JNI DetachCurrentThread() would have 1877 // returned JNI_ERR if there was a Java frame. JavaThread exit 1878 // should be done executing Java code by the time we get here. 1879 assert(!this->has_last_Java_frame(), 1880 "should not have a Java frame when detaching or exiting"); 1881 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1882 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1883 } 1884 1885 // These things needs to be done while we are still a Java Thread. Make sure that thread 1886 // is in a consistent state, in case GC happens 1887 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1888 1889 if (active_handles() != NULL) { 1890 JNIHandleBlock* block = active_handles(); 1891 set_active_handles(NULL); 1892 JNIHandleBlock::release_block(block); 1893 } 1894 1895 if (free_handle_block() != NULL) { 1896 JNIHandleBlock* block = free_handle_block(); 1897 set_free_handle_block(NULL); 1898 JNIHandleBlock::release_block(block); 1899 } 1900 1901 // These have to be removed while this is still a valid thread. 1902 remove_stack_guard_pages(); 1903 1904 if (UseTLAB) { 1905 tlab().make_parsable(true); // retire TLAB 1906 } 1907 1908 if (JvmtiEnv::environments_might_exist()) { 1909 JvmtiExport::cleanup_thread(this); 1910 } 1911 1912 // We must flush any deferred card marks before removing a thread from 1913 // the list of active threads. 1914 Universe::heap()->flush_deferred_store_barrier(this); 1915 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1916 1917 #if INCLUDE_ALL_GCS 1918 // We must flush the G1-related buffers before removing a thread 1919 // from the list of active threads. We must do this after any deferred 1920 // card marks have been flushed (above) so that any entries that are 1921 // added to the thread's dirty card queue as a result are not lost. 1922 if (UseG1GC) { 1923 flush_barrier_queues(); 1924 } 1925 #endif // INCLUDE_ALL_GCS 1926 1927 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1928 Threads::remove(this); 1929 } 1930 1931 #if INCLUDE_ALL_GCS 1932 // Flush G1-related queues. 1933 void JavaThread::flush_barrier_queues() { 1934 satb_mark_queue().flush(); 1935 dirty_card_queue().flush(); 1936 } 1937 1938 void JavaThread::initialize_queues() { 1939 assert(!SafepointSynchronize::is_at_safepoint(), 1940 "we should not be at a safepoint"); 1941 1942 SATBMarkQueue& satb_queue = satb_mark_queue(); 1943 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1944 // The SATB queue should have been constructed with its active 1945 // field set to false. 1946 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1947 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1948 // If we are creating the thread during a marking cycle, we should 1949 // set the active field of the SATB queue to true. 1950 if (satb_queue_set.is_active()) { 1951 satb_queue.set_active(true); 1952 } 1953 1954 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1955 // The dirty card queue should have been constructed with its 1956 // active field set to true. 1957 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1958 } 1959 #endif // INCLUDE_ALL_GCS 1960 1961 void JavaThread::cleanup_failed_attach_current_thread() { 1962 if (get_thread_profiler() != NULL) { 1963 get_thread_profiler()->disengage(); 1964 ResourceMark rm; 1965 get_thread_profiler()->print(get_thread_name()); 1966 } 1967 1968 if (active_handles() != NULL) { 1969 JNIHandleBlock* block = active_handles(); 1970 set_active_handles(NULL); 1971 JNIHandleBlock::release_block(block); 1972 } 1973 1974 if (free_handle_block() != NULL) { 1975 JNIHandleBlock* block = free_handle_block(); 1976 set_free_handle_block(NULL); 1977 JNIHandleBlock::release_block(block); 1978 } 1979 1980 // These have to be removed while this is still a valid thread. 1981 remove_stack_guard_pages(); 1982 1983 if (UseTLAB) { 1984 tlab().make_parsable(true); // retire TLAB, if any 1985 } 1986 1987 #if INCLUDE_ALL_GCS 1988 if (UseG1GC) { 1989 flush_barrier_queues(); 1990 } 1991 #endif // INCLUDE_ALL_GCS 1992 1993 Threads::remove(this); 1994 delete this; 1995 } 1996 1997 1998 1999 2000 JavaThread* JavaThread::active() { 2001 Thread* thread = Thread::current(); 2002 if (thread->is_Java_thread()) { 2003 return (JavaThread*) thread; 2004 } else { 2005 assert(thread->is_VM_thread(), "this must be a vm thread"); 2006 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2007 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2008 assert(ret->is_Java_thread(), "must be a Java thread"); 2009 return ret; 2010 } 2011 } 2012 2013 bool JavaThread::is_lock_owned(address adr) const { 2014 if (Thread::is_lock_owned(adr)) return true; 2015 2016 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2017 if (chunk->contains(adr)) return true; 2018 } 2019 2020 return false; 2021 } 2022 2023 2024 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2025 chunk->set_next(monitor_chunks()); 2026 set_monitor_chunks(chunk); 2027 } 2028 2029 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2030 guarantee(monitor_chunks() != NULL, "must be non empty"); 2031 if (monitor_chunks() == chunk) { 2032 set_monitor_chunks(chunk->next()); 2033 } else { 2034 MonitorChunk* prev = monitor_chunks(); 2035 while (prev->next() != chunk) prev = prev->next(); 2036 prev->set_next(chunk->next()); 2037 } 2038 } 2039 2040 // JVM support. 2041 2042 // Note: this function shouldn't block if it's called in 2043 // _thread_in_native_trans state (such as from 2044 // check_special_condition_for_native_trans()). 2045 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2046 2047 if (has_last_Java_frame() && has_async_condition()) { 2048 // If we are at a polling page safepoint (not a poll return) 2049 // then we must defer async exception because live registers 2050 // will be clobbered by the exception path. Poll return is 2051 // ok because the call we a returning from already collides 2052 // with exception handling registers and so there is no issue. 2053 // (The exception handling path kills call result registers but 2054 // this is ok since the exception kills the result anyway). 2055 2056 if (is_at_poll_safepoint()) { 2057 // if the code we are returning to has deoptimized we must defer 2058 // the exception otherwise live registers get clobbered on the 2059 // exception path before deoptimization is able to retrieve them. 2060 // 2061 RegisterMap map(this, false); 2062 frame caller_fr = last_frame().sender(&map); 2063 assert(caller_fr.is_compiled_frame(), "what?"); 2064 if (caller_fr.is_deoptimized_frame()) { 2065 log_info(exceptions)("deferred async exception at compiled safepoint"); 2066 return; 2067 } 2068 } 2069 } 2070 2071 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2072 if (condition == _no_async_condition) { 2073 // Conditions have changed since has_special_runtime_exit_condition() 2074 // was called: 2075 // - if we were here only because of an external suspend request, 2076 // then that was taken care of above (or cancelled) so we are done 2077 // - if we were here because of another async request, then it has 2078 // been cleared between the has_special_runtime_exit_condition() 2079 // and now so again we are done 2080 return; 2081 } 2082 2083 // Check for pending async. exception 2084 if (_pending_async_exception != NULL) { 2085 // Only overwrite an already pending exception, if it is not a threadDeath. 2086 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2087 2088 // We cannot call Exceptions::_throw(...) here because we cannot block 2089 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2090 2091 if (log_is_enabled(Info, exceptions)) { 2092 ResourceMark rm; 2093 outputStream* logstream = LogHandle(exceptions)::info_stream(); 2094 logstream->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); 2095 if (has_last_Java_frame()) { 2096 frame f = last_frame(); 2097 logstream->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); 2098 } 2099 logstream->print_cr(" of type: %s", _pending_async_exception->klass()->external_name()); 2100 } 2101 _pending_async_exception = NULL; 2102 clear_has_async_exception(); 2103 } 2104 } 2105 2106 if (check_unsafe_error && 2107 condition == _async_unsafe_access_error && !has_pending_exception()) { 2108 condition = _no_async_condition; // done 2109 switch (thread_state()) { 2110 case _thread_in_vm: { 2111 JavaThread* THREAD = this; 2112 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2113 } 2114 case _thread_in_native: { 2115 ThreadInVMfromNative tiv(this); 2116 JavaThread* THREAD = this; 2117 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2118 } 2119 case _thread_in_Java: { 2120 ThreadInVMfromJava tiv(this); 2121 JavaThread* THREAD = this; 2122 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2123 } 2124 default: 2125 ShouldNotReachHere(); 2126 } 2127 } 2128 2129 assert(condition == _no_async_condition || has_pending_exception() || 2130 (!check_unsafe_error && condition == _async_unsafe_access_error), 2131 "must have handled the async condition, if no exception"); 2132 } 2133 2134 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2135 // 2136 // Check for pending external suspend. Internal suspend requests do 2137 // not use handle_special_runtime_exit_condition(). 2138 // If JNIEnv proxies are allowed, don't self-suspend if the target 2139 // thread is not the current thread. In older versions of jdbx, jdbx 2140 // threads could call into the VM with another thread's JNIEnv so we 2141 // can be here operating on behalf of a suspended thread (4432884). 2142 bool do_self_suspend = is_external_suspend_with_lock(); 2143 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2144 // 2145 // Because thread is external suspended the safepoint code will count 2146 // thread as at a safepoint. This can be odd because we can be here 2147 // as _thread_in_Java which would normally transition to _thread_blocked 2148 // at a safepoint. We would like to mark the thread as _thread_blocked 2149 // before calling java_suspend_self like all other callers of it but 2150 // we must then observe proper safepoint protocol. (We can't leave 2151 // _thread_blocked with a safepoint in progress). However we can be 2152 // here as _thread_in_native_trans so we can't use a normal transition 2153 // constructor/destructor pair because they assert on that type of 2154 // transition. We could do something like: 2155 // 2156 // JavaThreadState state = thread_state(); 2157 // set_thread_state(_thread_in_vm); 2158 // { 2159 // ThreadBlockInVM tbivm(this); 2160 // java_suspend_self() 2161 // } 2162 // set_thread_state(_thread_in_vm_trans); 2163 // if (safepoint) block; 2164 // set_thread_state(state); 2165 // 2166 // but that is pretty messy. Instead we just go with the way the 2167 // code has worked before and note that this is the only path to 2168 // java_suspend_self that doesn't put the thread in _thread_blocked 2169 // mode. 2170 2171 frame_anchor()->make_walkable(this); 2172 java_suspend_self(); 2173 2174 // We might be here for reasons in addition to the self-suspend request 2175 // so check for other async requests. 2176 } 2177 2178 if (check_asyncs) { 2179 check_and_handle_async_exceptions(); 2180 } 2181 } 2182 2183 void JavaThread::send_thread_stop(oop java_throwable) { 2184 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2185 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2186 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2187 2188 // Do not throw asynchronous exceptions against the compiler thread 2189 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2190 if (!can_call_java()) return; 2191 2192 { 2193 // Actually throw the Throwable against the target Thread - however 2194 // only if there is no thread death exception installed already. 2195 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2196 // If the topmost frame is a runtime stub, then we are calling into 2197 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2198 // must deoptimize the caller before continuing, as the compiled exception handler table 2199 // may not be valid 2200 if (has_last_Java_frame()) { 2201 frame f = last_frame(); 2202 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2203 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2204 RegisterMap reg_map(this, UseBiasedLocking); 2205 frame compiled_frame = f.sender(®_map); 2206 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2207 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2208 } 2209 } 2210 } 2211 2212 // Set async. pending exception in thread. 2213 set_pending_async_exception(java_throwable); 2214 2215 if (log_is_enabled(Info, exceptions)) { 2216 ResourceMark rm; 2217 log_info(exceptions)("Pending Async. exception installed of type: %s", 2218 InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2219 } 2220 // for AbortVMOnException flag 2221 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name()); 2222 } 2223 } 2224 2225 2226 // Interrupt thread so it will wake up from a potential wait() 2227 Thread::interrupt(this); 2228 } 2229 2230 // External suspension mechanism. 2231 // 2232 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2233 // to any VM_locks and it is at a transition 2234 // Self-suspension will happen on the transition out of the vm. 2235 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2236 // 2237 // Guarantees on return: 2238 // + Target thread will not execute any new bytecode (that's why we need to 2239 // force a safepoint) 2240 // + Target thread will not enter any new monitors 2241 // 2242 void JavaThread::java_suspend() { 2243 { MutexLocker mu(Threads_lock); 2244 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2245 return; 2246 } 2247 } 2248 2249 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2250 if (!is_external_suspend()) { 2251 // a racing resume has cancelled us; bail out now 2252 return; 2253 } 2254 2255 // suspend is done 2256 uint32_t debug_bits = 0; 2257 // Warning: is_ext_suspend_completed() may temporarily drop the 2258 // SR_lock to allow the thread to reach a stable thread state if 2259 // it is currently in a transient thread state. 2260 if (is_ext_suspend_completed(false /* !called_by_wait */, 2261 SuspendRetryDelay, &debug_bits)) { 2262 return; 2263 } 2264 } 2265 2266 VM_ForceSafepoint vm_suspend; 2267 VMThread::execute(&vm_suspend); 2268 } 2269 2270 // Part II of external suspension. 2271 // A JavaThread self suspends when it detects a pending external suspend 2272 // request. This is usually on transitions. It is also done in places 2273 // where continuing to the next transition would surprise the caller, 2274 // e.g., monitor entry. 2275 // 2276 // Returns the number of times that the thread self-suspended. 2277 // 2278 // Note: DO NOT call java_suspend_self() when you just want to block current 2279 // thread. java_suspend_self() is the second stage of cooperative 2280 // suspension for external suspend requests and should only be used 2281 // to complete an external suspend request. 2282 // 2283 int JavaThread::java_suspend_self() { 2284 int ret = 0; 2285 2286 // we are in the process of exiting so don't suspend 2287 if (is_exiting()) { 2288 clear_external_suspend(); 2289 return ret; 2290 } 2291 2292 assert(_anchor.walkable() || 2293 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2294 "must have walkable stack"); 2295 2296 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2297 2298 assert(!this->is_ext_suspended(), 2299 "a thread trying to self-suspend should not already be suspended"); 2300 2301 if (this->is_suspend_equivalent()) { 2302 // If we are self-suspending as a result of the lifting of a 2303 // suspend equivalent condition, then the suspend_equivalent 2304 // flag is not cleared until we set the ext_suspended flag so 2305 // that wait_for_ext_suspend_completion() returns consistent 2306 // results. 2307 this->clear_suspend_equivalent(); 2308 } 2309 2310 // A racing resume may have cancelled us before we grabbed SR_lock 2311 // above. Or another external suspend request could be waiting for us 2312 // by the time we return from SR_lock()->wait(). The thread 2313 // that requested the suspension may already be trying to walk our 2314 // stack and if we return now, we can change the stack out from under 2315 // it. This would be a "bad thing (TM)" and cause the stack walker 2316 // to crash. We stay self-suspended until there are no more pending 2317 // external suspend requests. 2318 while (is_external_suspend()) { 2319 ret++; 2320 this->set_ext_suspended(); 2321 2322 // _ext_suspended flag is cleared by java_resume() 2323 while (is_ext_suspended()) { 2324 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2325 } 2326 } 2327 2328 return ret; 2329 } 2330 2331 #ifdef ASSERT 2332 // verify the JavaThread has not yet been published in the Threads::list, and 2333 // hence doesn't need protection from concurrent access at this stage 2334 void JavaThread::verify_not_published() { 2335 if (!Threads_lock->owned_by_self()) { 2336 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2337 assert(!Threads::includes(this), 2338 "java thread shouldn't have been published yet!"); 2339 } else { 2340 assert(!Threads::includes(this), 2341 "java thread shouldn't have been published yet!"); 2342 } 2343 } 2344 #endif 2345 2346 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2347 // progress or when _suspend_flags is non-zero. 2348 // Current thread needs to self-suspend if there is a suspend request and/or 2349 // block if a safepoint is in progress. 2350 // Async exception ISN'T checked. 2351 // Note only the ThreadInVMfromNative transition can call this function 2352 // directly and when thread state is _thread_in_native_trans 2353 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2354 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2355 2356 JavaThread *curJT = JavaThread::current(); 2357 bool do_self_suspend = thread->is_external_suspend(); 2358 2359 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2360 2361 // If JNIEnv proxies are allowed, don't self-suspend if the target 2362 // thread is not the current thread. In older versions of jdbx, jdbx 2363 // threads could call into the VM with another thread's JNIEnv so we 2364 // can be here operating on behalf of a suspended thread (4432884). 2365 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2366 JavaThreadState state = thread->thread_state(); 2367 2368 // We mark this thread_blocked state as a suspend-equivalent so 2369 // that a caller to is_ext_suspend_completed() won't be confused. 2370 // The suspend-equivalent state is cleared by java_suspend_self(). 2371 thread->set_suspend_equivalent(); 2372 2373 // If the safepoint code sees the _thread_in_native_trans state, it will 2374 // wait until the thread changes to other thread state. There is no 2375 // guarantee on how soon we can obtain the SR_lock and complete the 2376 // self-suspend request. It would be a bad idea to let safepoint wait for 2377 // too long. Temporarily change the state to _thread_blocked to 2378 // let the VM thread know that this thread is ready for GC. The problem 2379 // of changing thread state is that safepoint could happen just after 2380 // java_suspend_self() returns after being resumed, and VM thread will 2381 // see the _thread_blocked state. We must check for safepoint 2382 // after restoring the state and make sure we won't leave while a safepoint 2383 // is in progress. 2384 thread->set_thread_state(_thread_blocked); 2385 thread->java_suspend_self(); 2386 thread->set_thread_state(state); 2387 // Make sure new state is seen by VM thread 2388 if (os::is_MP()) { 2389 if (UseMembar) { 2390 // Force a fence between the write above and read below 2391 OrderAccess::fence(); 2392 } else { 2393 // Must use this rather than serialization page in particular on Windows 2394 InterfaceSupport::serialize_memory(thread); 2395 } 2396 } 2397 } 2398 2399 if (SafepointSynchronize::do_call_back()) { 2400 // If we are safepointing, then block the caller which may not be 2401 // the same as the target thread (see above). 2402 SafepointSynchronize::block(curJT); 2403 } 2404 2405 if (thread->is_deopt_suspend()) { 2406 thread->clear_deopt_suspend(); 2407 RegisterMap map(thread, false); 2408 frame f = thread->last_frame(); 2409 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2410 f = f.sender(&map); 2411 } 2412 if (f.id() == thread->must_deopt_id()) { 2413 thread->clear_must_deopt_id(); 2414 f.deoptimize(thread); 2415 } else { 2416 fatal("missed deoptimization!"); 2417 } 2418 } 2419 } 2420 2421 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2422 // progress or when _suspend_flags is non-zero. 2423 // Current thread needs to self-suspend if there is a suspend request and/or 2424 // block if a safepoint is in progress. 2425 // Also check for pending async exception (not including unsafe access error). 2426 // Note only the native==>VM/Java barriers can call this function and when 2427 // thread state is _thread_in_native_trans. 2428 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2429 check_safepoint_and_suspend_for_native_trans(thread); 2430 2431 if (thread->has_async_exception()) { 2432 // We are in _thread_in_native_trans state, don't handle unsafe 2433 // access error since that may block. 2434 thread->check_and_handle_async_exceptions(false); 2435 } 2436 } 2437 2438 // This is a variant of the normal 2439 // check_special_condition_for_native_trans with slightly different 2440 // semantics for use by critical native wrappers. It does all the 2441 // normal checks but also performs the transition back into 2442 // thread_in_Java state. This is required so that critical natives 2443 // can potentially block and perform a GC if they are the last thread 2444 // exiting the GCLocker. 2445 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2446 check_special_condition_for_native_trans(thread); 2447 2448 // Finish the transition 2449 thread->set_thread_state(_thread_in_Java); 2450 2451 if (thread->do_critical_native_unlock()) { 2452 ThreadInVMfromJavaNoAsyncException tiv(thread); 2453 GCLocker::unlock_critical(thread); 2454 thread->clear_critical_native_unlock(); 2455 } 2456 } 2457 2458 // We need to guarantee the Threads_lock here, since resumes are not 2459 // allowed during safepoint synchronization 2460 // Can only resume from an external suspension 2461 void JavaThread::java_resume() { 2462 assert_locked_or_safepoint(Threads_lock); 2463 2464 // Sanity check: thread is gone, has started exiting or the thread 2465 // was not externally suspended. 2466 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2467 return; 2468 } 2469 2470 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2471 2472 clear_external_suspend(); 2473 2474 if (is_ext_suspended()) { 2475 clear_ext_suspended(); 2476 SR_lock()->notify_all(); 2477 } 2478 } 2479 2480 size_t JavaThread::_stack_red_zone_size = 0; 2481 size_t JavaThread::_stack_yellow_zone_size = 0; 2482 size_t JavaThread::_stack_reserved_zone_size = 0; 2483 size_t JavaThread::_stack_shadow_zone_size = 0; 2484 2485 void JavaThread::create_stack_guard_pages() { 2486 if (!os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) { return; } 2487 address low_addr = stack_end(); 2488 size_t len = stack_guard_zone_size(); 2489 2490 int allocate = os::allocate_stack_guard_pages(); 2491 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2492 2493 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2494 warning("Attempt to allocate stack guard pages failed."); 2495 return; 2496 } 2497 2498 if (os::guard_memory((char *) low_addr, len)) { 2499 _stack_guard_state = stack_guard_enabled; 2500 } else { 2501 warning("Attempt to protect stack guard pages failed."); 2502 if (os::uncommit_memory((char *) low_addr, len)) { 2503 warning("Attempt to deallocate stack guard pages failed."); 2504 } 2505 } 2506 } 2507 2508 void JavaThread::remove_stack_guard_pages() { 2509 assert(Thread::current() == this, "from different thread"); 2510 if (_stack_guard_state == stack_guard_unused) return; 2511 address low_addr = stack_end(); 2512 size_t len = stack_guard_zone_size(); 2513 2514 if (os::allocate_stack_guard_pages()) { 2515 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2516 _stack_guard_state = stack_guard_unused; 2517 } else { 2518 warning("Attempt to deallocate stack guard pages failed."); 2519 } 2520 } else { 2521 if (_stack_guard_state == stack_guard_unused) return; 2522 if (os::unguard_memory((char *) low_addr, len)) { 2523 _stack_guard_state = stack_guard_unused; 2524 } else { 2525 warning("Attempt to unprotect stack guard pages failed."); 2526 } 2527 } 2528 } 2529 2530 void JavaThread::enable_stack_reserved_zone() { 2531 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2532 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2533 2534 // The base notation is from the stack's point of view, growing downward. 2535 // We need to adjust it to work correctly with guard_memory() 2536 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2537 2538 guarantee(base < stack_base(),"Error calculating stack reserved zone"); 2539 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone"); 2540 2541 if (os::guard_memory((char *) base, stack_reserved_zone_size())) { 2542 _stack_guard_state = stack_guard_enabled; 2543 } else { 2544 warning("Attempt to guard stack reserved zone failed."); 2545 } 2546 enable_register_stack_guard(); 2547 } 2548 2549 void JavaThread::disable_stack_reserved_zone() { 2550 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2551 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled"); 2552 2553 // Simply return if called for a thread that does not use guard pages. 2554 if (_stack_guard_state == stack_guard_unused) return; 2555 2556 // The base notation is from the stack's point of view, growing downward. 2557 // We need to adjust it to work correctly with guard_memory() 2558 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2559 2560 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) { 2561 _stack_guard_state = stack_guard_reserved_disabled; 2562 } else { 2563 warning("Attempt to unguard stack reserved zone failed."); 2564 } 2565 disable_register_stack_guard(); 2566 } 2567 2568 void JavaThread::enable_stack_yellow_reserved_zone() { 2569 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2570 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2571 2572 // The base notation is from the stacks point of view, growing downward. 2573 // We need to adjust it to work correctly with guard_memory() 2574 address base = stack_red_zone_base(); 2575 2576 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2577 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2578 2579 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) { 2580 _stack_guard_state = stack_guard_enabled; 2581 } else { 2582 warning("Attempt to guard stack yellow zone failed."); 2583 } 2584 enable_register_stack_guard(); 2585 } 2586 2587 void JavaThread::disable_stack_yellow_reserved_zone() { 2588 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2589 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled"); 2590 2591 // Simply return if called for a thread that does not use guard pages. 2592 if (_stack_guard_state == stack_guard_unused) return; 2593 2594 // The base notation is from the stacks point of view, growing downward. 2595 // We need to adjust it to work correctly with guard_memory() 2596 address base = stack_red_zone_base(); 2597 2598 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) { 2599 _stack_guard_state = stack_guard_yellow_reserved_disabled; 2600 } else { 2601 warning("Attempt to unguard stack yellow zone failed."); 2602 } 2603 disable_register_stack_guard(); 2604 } 2605 2606 void JavaThread::enable_stack_red_zone() { 2607 // The base notation is from the stacks point of view, growing downward. 2608 // We need to adjust it to work correctly with guard_memory() 2609 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2610 address base = stack_red_zone_base() - stack_red_zone_size(); 2611 2612 guarantee(base < stack_base(), "Error calculating stack red zone"); 2613 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2614 2615 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2616 warning("Attempt to guard stack red zone failed."); 2617 } 2618 } 2619 2620 void JavaThread::disable_stack_red_zone() { 2621 // The base notation is from the stacks point of view, growing downward. 2622 // We need to adjust it to work correctly with guard_memory() 2623 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2624 address base = stack_red_zone_base() - stack_red_zone_size(); 2625 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2626 warning("Attempt to unguard stack red zone failed."); 2627 } 2628 } 2629 2630 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2631 // ignore is there is no stack 2632 if (!has_last_Java_frame()) return; 2633 // traverse the stack frames. Starts from top frame. 2634 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2635 frame* fr = fst.current(); 2636 f(fr, fst.register_map()); 2637 } 2638 } 2639 2640 2641 #ifndef PRODUCT 2642 // Deoptimization 2643 // Function for testing deoptimization 2644 void JavaThread::deoptimize() { 2645 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2646 StackFrameStream fst(this, UseBiasedLocking); 2647 bool deopt = false; // Dump stack only if a deopt actually happens. 2648 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2649 // Iterate over all frames in the thread and deoptimize 2650 for (; !fst.is_done(); fst.next()) { 2651 if (fst.current()->can_be_deoptimized()) { 2652 2653 if (only_at) { 2654 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2655 // consists of comma or carriage return separated numbers so 2656 // search for the current bci in that string. 2657 address pc = fst.current()->pc(); 2658 nmethod* nm = (nmethod*) fst.current()->cb(); 2659 ScopeDesc* sd = nm->scope_desc_at(pc); 2660 char buffer[8]; 2661 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2662 size_t len = strlen(buffer); 2663 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2664 while (found != NULL) { 2665 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2666 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2667 // Check that the bci found is bracketed by terminators. 2668 break; 2669 } 2670 found = strstr(found + 1, buffer); 2671 } 2672 if (!found) { 2673 continue; 2674 } 2675 } 2676 2677 if (DebugDeoptimization && !deopt) { 2678 deopt = true; // One-time only print before deopt 2679 tty->print_cr("[BEFORE Deoptimization]"); 2680 trace_frames(); 2681 trace_stack(); 2682 } 2683 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2684 } 2685 } 2686 2687 if (DebugDeoptimization && deopt) { 2688 tty->print_cr("[AFTER Deoptimization]"); 2689 trace_frames(); 2690 } 2691 } 2692 2693 2694 // Make zombies 2695 void JavaThread::make_zombies() { 2696 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2697 if (fst.current()->can_be_deoptimized()) { 2698 // it is a Java nmethod 2699 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2700 nm->make_not_entrant(); 2701 } 2702 } 2703 } 2704 #endif // PRODUCT 2705 2706 2707 void JavaThread::deoptimized_wrt_marked_nmethods() { 2708 if (!has_last_Java_frame()) return; 2709 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2710 StackFrameStream fst(this, UseBiasedLocking); 2711 for (; !fst.is_done(); fst.next()) { 2712 if (fst.current()->should_be_deoptimized()) { 2713 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2714 } 2715 } 2716 } 2717 2718 2719 // If the caller is a NamedThread, then remember, in the current scope, 2720 // the given JavaThread in its _processed_thread field. 2721 class RememberProcessedThread: public StackObj { 2722 NamedThread* _cur_thr; 2723 public: 2724 RememberProcessedThread(JavaThread* jthr) { 2725 Thread* thread = Thread::current(); 2726 if (thread->is_Named_thread()) { 2727 _cur_thr = (NamedThread *)thread; 2728 _cur_thr->set_processed_thread(jthr); 2729 } else { 2730 _cur_thr = NULL; 2731 } 2732 } 2733 2734 ~RememberProcessedThread() { 2735 if (_cur_thr) { 2736 _cur_thr->set_processed_thread(NULL); 2737 } 2738 } 2739 }; 2740 2741 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2742 // Verify that the deferred card marks have been flushed. 2743 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2744 2745 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2746 // since there may be more than one thread using each ThreadProfiler. 2747 2748 // Traverse the GCHandles 2749 Thread::oops_do(f, cld_f, cf); 2750 2751 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);) 2752 2753 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2754 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2755 2756 if (has_last_Java_frame()) { 2757 // Record JavaThread to GC thread 2758 RememberProcessedThread rpt(this); 2759 2760 // Traverse the privileged stack 2761 if (_privileged_stack_top != NULL) { 2762 _privileged_stack_top->oops_do(f); 2763 } 2764 2765 // traverse the registered growable array 2766 if (_array_for_gc != NULL) { 2767 for (int index = 0; index < _array_for_gc->length(); index++) { 2768 f->do_oop(_array_for_gc->adr_at(index)); 2769 } 2770 } 2771 2772 // Traverse the monitor chunks 2773 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2774 chunk->oops_do(f); 2775 } 2776 2777 // Traverse the execution stack 2778 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2779 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2780 } 2781 } 2782 2783 // callee_target is never live across a gc point so NULL it here should 2784 // it still contain a methdOop. 2785 2786 set_callee_target(NULL); 2787 2788 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2789 // If we have deferred set_locals there might be oops waiting to be 2790 // written 2791 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2792 if (list != NULL) { 2793 for (int i = 0; i < list->length(); i++) { 2794 list->at(i)->oops_do(f); 2795 } 2796 } 2797 2798 // Traverse instance variables at the end since the GC may be moving things 2799 // around using this function 2800 f->do_oop((oop*) &_threadObj); 2801 f->do_oop((oop*) &_vm_result); 2802 f->do_oop((oop*) &_exception_oop); 2803 f->do_oop((oop*) &_pending_async_exception); 2804 2805 if (jvmti_thread_state() != NULL) { 2806 jvmti_thread_state()->oops_do(f); 2807 } 2808 } 2809 2810 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2811 Thread::nmethods_do(cf); // (super method is a no-op) 2812 2813 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2814 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2815 2816 if (has_last_Java_frame()) { 2817 // Traverse the execution stack 2818 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2819 fst.current()->nmethods_do(cf); 2820 } 2821 } 2822 } 2823 2824 void JavaThread::metadata_do(void f(Metadata*)) { 2825 if (has_last_Java_frame()) { 2826 // Traverse the execution stack to call f() on the methods in the stack 2827 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2828 fst.current()->metadata_do(f); 2829 } 2830 } else if (is_Compiler_thread()) { 2831 // need to walk ciMetadata in current compile tasks to keep alive. 2832 CompilerThread* ct = (CompilerThread*)this; 2833 if (ct->env() != NULL) { 2834 ct->env()->metadata_do(f); 2835 } 2836 if (ct->task() != NULL) { 2837 ct->task()->metadata_do(f); 2838 } 2839 } 2840 } 2841 2842 // Printing 2843 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2844 switch (_thread_state) { 2845 case _thread_uninitialized: return "_thread_uninitialized"; 2846 case _thread_new: return "_thread_new"; 2847 case _thread_new_trans: return "_thread_new_trans"; 2848 case _thread_in_native: return "_thread_in_native"; 2849 case _thread_in_native_trans: return "_thread_in_native_trans"; 2850 case _thread_in_vm: return "_thread_in_vm"; 2851 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2852 case _thread_in_Java: return "_thread_in_Java"; 2853 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2854 case _thread_blocked: return "_thread_blocked"; 2855 case _thread_blocked_trans: return "_thread_blocked_trans"; 2856 default: return "unknown thread state"; 2857 } 2858 } 2859 2860 #ifndef PRODUCT 2861 void JavaThread::print_thread_state_on(outputStream *st) const { 2862 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2863 }; 2864 void JavaThread::print_thread_state() const { 2865 print_thread_state_on(tty); 2866 } 2867 #endif // PRODUCT 2868 2869 // Called by Threads::print() for VM_PrintThreads operation 2870 void JavaThread::print_on(outputStream *st) const { 2871 st->print("\"%s\" ", get_thread_name()); 2872 oop thread_oop = threadObj(); 2873 if (thread_oop != NULL) { 2874 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2875 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2876 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2877 } 2878 Thread::print_on(st); 2879 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2880 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2881 if (thread_oop != NULL) { 2882 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2883 } 2884 #ifndef PRODUCT 2885 print_thread_state_on(st); 2886 _safepoint_state->print_on(st); 2887 #endif // PRODUCT 2888 if (is_Compiler_thread()) { 2889 CompilerThread* ct = (CompilerThread*)this; 2890 if (ct->task() != NULL) { 2891 st->print(" Compiling: "); 2892 ct->task()->print(st, NULL, true, false); 2893 } else { 2894 st->print(" No compile task"); 2895 } 2896 st->cr(); 2897 } 2898 } 2899 2900 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const { 2901 st->print("%s", get_thread_name_string(buf, buflen)); 2902 } 2903 2904 // Called by fatal error handler. The difference between this and 2905 // JavaThread::print() is that we can't grab lock or allocate memory. 2906 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2907 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2908 oop thread_obj = threadObj(); 2909 if (thread_obj != NULL) { 2910 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2911 } 2912 st->print(" ["); 2913 st->print("%s", _get_thread_state_name(_thread_state)); 2914 if (osthread()) { 2915 st->print(", id=%d", osthread()->thread_id()); 2916 } 2917 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2918 p2i(stack_end()), p2i(stack_base())); 2919 st->print("]"); 2920 return; 2921 } 2922 2923 // Verification 2924 2925 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2926 2927 void JavaThread::verify() { 2928 // Verify oops in the thread. 2929 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2930 2931 // Verify the stack frames. 2932 frames_do(frame_verify); 2933 } 2934 2935 // CR 6300358 (sub-CR 2137150) 2936 // Most callers of this method assume that it can't return NULL but a 2937 // thread may not have a name whilst it is in the process of attaching to 2938 // the VM - see CR 6412693, and there are places where a JavaThread can be 2939 // seen prior to having it's threadObj set (eg JNI attaching threads and 2940 // if vm exit occurs during initialization). These cases can all be accounted 2941 // for such that this method never returns NULL. 2942 const char* JavaThread::get_thread_name() const { 2943 #ifdef ASSERT 2944 // early safepoints can hit while current thread does not yet have TLS 2945 if (!SafepointSynchronize::is_at_safepoint()) { 2946 Thread *cur = Thread::current(); 2947 if (!(cur->is_Java_thread() && cur == this)) { 2948 // Current JavaThreads are allowed to get their own name without 2949 // the Threads_lock. 2950 assert_locked_or_safepoint(Threads_lock); 2951 } 2952 } 2953 #endif // ASSERT 2954 return get_thread_name_string(); 2955 } 2956 2957 // Returns a non-NULL representation of this thread's name, or a suitable 2958 // descriptive string if there is no set name 2959 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2960 const char* name_str; 2961 oop thread_obj = threadObj(); 2962 if (thread_obj != NULL) { 2963 oop name = java_lang_Thread::name(thread_obj); 2964 if (name != NULL) { 2965 if (buf == NULL) { 2966 name_str = java_lang_String::as_utf8_string(name); 2967 } else { 2968 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 2969 } 2970 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2971 name_str = "<no-name - thread is attaching>"; 2972 } else { 2973 name_str = Thread::name(); 2974 } 2975 } else { 2976 name_str = Thread::name(); 2977 } 2978 assert(name_str != NULL, "unexpected NULL thread name"); 2979 return name_str; 2980 } 2981 2982 2983 const char* JavaThread::get_threadgroup_name() const { 2984 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2985 oop thread_obj = threadObj(); 2986 if (thread_obj != NULL) { 2987 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2988 if (thread_group != NULL) { 2989 // ThreadGroup.name can be null 2990 return java_lang_ThreadGroup::name(thread_group); 2991 } 2992 } 2993 return NULL; 2994 } 2995 2996 const char* JavaThread::get_parent_name() const { 2997 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2998 oop thread_obj = threadObj(); 2999 if (thread_obj != NULL) { 3000 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 3001 if (thread_group != NULL) { 3002 oop parent = java_lang_ThreadGroup::parent(thread_group); 3003 if (parent != NULL) { 3004 // ThreadGroup.name can be null 3005 return java_lang_ThreadGroup::name(parent); 3006 } 3007 } 3008 } 3009 return NULL; 3010 } 3011 3012 ThreadPriority JavaThread::java_priority() const { 3013 oop thr_oop = threadObj(); 3014 if (thr_oop == NULL) return NormPriority; // Bootstrapping 3015 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 3016 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 3017 return priority; 3018 } 3019 3020 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 3021 3022 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3023 // Link Java Thread object <-> C++ Thread 3024 3025 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3026 // and put it into a new Handle. The Handle "thread_oop" can then 3027 // be used to pass the C++ thread object to other methods. 3028 3029 // Set the Java level thread object (jthread) field of the 3030 // new thread (a JavaThread *) to C++ thread object using the 3031 // "thread_oop" handle. 3032 3033 // Set the thread field (a JavaThread *) of the 3034 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3035 3036 Handle thread_oop(Thread::current(), 3037 JNIHandles::resolve_non_null(jni_thread)); 3038 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3039 "must be initialized"); 3040 set_threadObj(thread_oop()); 3041 java_lang_Thread::set_thread(thread_oop(), this); 3042 3043 if (prio == NoPriority) { 3044 prio = java_lang_Thread::priority(thread_oop()); 3045 assert(prio != NoPriority, "A valid priority should be present"); 3046 } 3047 3048 // Push the Java priority down to the native thread; needs Threads_lock 3049 Thread::set_priority(this, prio); 3050 3051 prepare_ext(); 3052 3053 // Add the new thread to the Threads list and set it in motion. 3054 // We must have threads lock in order to call Threads::add. 3055 // It is crucial that we do not block before the thread is 3056 // added to the Threads list for if a GC happens, then the java_thread oop 3057 // will not be visited by GC. 3058 Threads::add(this); 3059 } 3060 3061 oop JavaThread::current_park_blocker() { 3062 // Support for JSR-166 locks 3063 oop thread_oop = threadObj(); 3064 if (thread_oop != NULL && 3065 JDK_Version::current().supports_thread_park_blocker()) { 3066 return java_lang_Thread::park_blocker(thread_oop); 3067 } 3068 return NULL; 3069 } 3070 3071 3072 void JavaThread::print_stack_on(outputStream* st) { 3073 if (!has_last_Java_frame()) return; 3074 ResourceMark rm; 3075 HandleMark hm; 3076 3077 RegisterMap reg_map(this); 3078 vframe* start_vf = last_java_vframe(®_map); 3079 int count = 0; 3080 for (vframe* f = start_vf; f; f = f->sender()) { 3081 if (f->is_java_frame()) { 3082 javaVFrame* jvf = javaVFrame::cast(f); 3083 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3084 3085 // Print out lock information 3086 if (JavaMonitorsInStackTrace) { 3087 jvf->print_lock_info_on(st, count); 3088 } 3089 } else { 3090 // Ignore non-Java frames 3091 } 3092 3093 // Bail-out case for too deep stacks 3094 count++; 3095 if (MaxJavaStackTraceDepth == count) return; 3096 } 3097 } 3098 3099 3100 // JVMTI PopFrame support 3101 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3102 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3103 if (in_bytes(size_in_bytes) != 0) { 3104 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3105 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3106 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3107 } 3108 } 3109 3110 void* JavaThread::popframe_preserved_args() { 3111 return _popframe_preserved_args; 3112 } 3113 3114 ByteSize JavaThread::popframe_preserved_args_size() { 3115 return in_ByteSize(_popframe_preserved_args_size); 3116 } 3117 3118 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3119 int sz = in_bytes(popframe_preserved_args_size()); 3120 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3121 return in_WordSize(sz / wordSize); 3122 } 3123 3124 void JavaThread::popframe_free_preserved_args() { 3125 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3126 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3127 _popframe_preserved_args = NULL; 3128 _popframe_preserved_args_size = 0; 3129 } 3130 3131 #ifndef PRODUCT 3132 3133 void JavaThread::trace_frames() { 3134 tty->print_cr("[Describe stack]"); 3135 int frame_no = 1; 3136 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3137 tty->print(" %d. ", frame_no++); 3138 fst.current()->print_value_on(tty, this); 3139 tty->cr(); 3140 } 3141 } 3142 3143 class PrintAndVerifyOopClosure: public OopClosure { 3144 protected: 3145 template <class T> inline void do_oop_work(T* p) { 3146 oop obj = oopDesc::load_decode_heap_oop(p); 3147 if (obj == NULL) return; 3148 tty->print(INTPTR_FORMAT ": ", p2i(p)); 3149 if (obj->is_oop_or_null()) { 3150 if (obj->is_objArray()) { 3151 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); 3152 } else { 3153 obj->print(); 3154 } 3155 } else { 3156 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); 3157 } 3158 tty->cr(); 3159 } 3160 public: 3161 virtual void do_oop(oop* p) { do_oop_work(p); } 3162 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3163 }; 3164 3165 3166 static void oops_print(frame* f, const RegisterMap *map) { 3167 PrintAndVerifyOopClosure print; 3168 f->print_value(); 3169 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3170 } 3171 3172 // Print our all the locations that contain oops and whether they are 3173 // valid or not. This useful when trying to find the oldest frame 3174 // where an oop has gone bad since the frame walk is from youngest to 3175 // oldest. 3176 void JavaThread::trace_oops() { 3177 tty->print_cr("[Trace oops]"); 3178 frames_do(oops_print); 3179 } 3180 3181 3182 #ifdef ASSERT 3183 // Print or validate the layout of stack frames 3184 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3185 ResourceMark rm; 3186 PRESERVE_EXCEPTION_MARK; 3187 FrameValues values; 3188 int frame_no = 0; 3189 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3190 fst.current()->describe(values, ++frame_no); 3191 if (depth == frame_no) break; 3192 } 3193 if (validate_only) { 3194 values.validate(); 3195 } else { 3196 tty->print_cr("[Describe stack layout]"); 3197 values.print(this); 3198 } 3199 } 3200 #endif 3201 3202 void JavaThread::trace_stack_from(vframe* start_vf) { 3203 ResourceMark rm; 3204 int vframe_no = 1; 3205 for (vframe* f = start_vf; f; f = f->sender()) { 3206 if (f->is_java_frame()) { 3207 javaVFrame::cast(f)->print_activation(vframe_no++); 3208 } else { 3209 f->print(); 3210 } 3211 if (vframe_no > StackPrintLimit) { 3212 tty->print_cr("...<more frames>..."); 3213 return; 3214 } 3215 } 3216 } 3217 3218 3219 void JavaThread::trace_stack() { 3220 if (!has_last_Java_frame()) return; 3221 ResourceMark rm; 3222 HandleMark hm; 3223 RegisterMap reg_map(this); 3224 trace_stack_from(last_java_vframe(®_map)); 3225 } 3226 3227 3228 #endif // PRODUCT 3229 3230 3231 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3232 assert(reg_map != NULL, "a map must be given"); 3233 frame f = last_frame(); 3234 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3235 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3236 } 3237 return NULL; 3238 } 3239 3240 3241 Klass* JavaThread::security_get_caller_class(int depth) { 3242 vframeStream vfst(this); 3243 vfst.security_get_caller_frame(depth); 3244 if (!vfst.at_end()) { 3245 return vfst.method()->method_holder(); 3246 } 3247 return NULL; 3248 } 3249 3250 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3251 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3252 CompileBroker::compiler_thread_loop(); 3253 } 3254 3255 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3256 NMethodSweeper::sweeper_loop(); 3257 } 3258 3259 // Create a CompilerThread 3260 CompilerThread::CompilerThread(CompileQueue* queue, 3261 CompilerCounters* counters) 3262 : JavaThread(&compiler_thread_entry) { 3263 _env = NULL; 3264 _log = NULL; 3265 _task = NULL; 3266 _queue = queue; 3267 _counters = counters; 3268 _buffer_blob = NULL; 3269 _compiler = NULL; 3270 3271 #ifndef PRODUCT 3272 _ideal_graph_printer = NULL; 3273 #endif 3274 } 3275 3276 bool CompilerThread::can_call_java() const { 3277 return _compiler != NULL && _compiler->is_jvmci(); 3278 } 3279 3280 // Create sweeper thread 3281 CodeCacheSweeperThread::CodeCacheSweeperThread() 3282 : JavaThread(&sweeper_thread_entry) { 3283 _scanned_nmethod = NULL; 3284 } 3285 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3286 JavaThread::oops_do(f, cld_f, cf); 3287 if (_scanned_nmethod != NULL && cf != NULL) { 3288 // Safepoints can occur when the sweeper is scanning an nmethod so 3289 // process it here to make sure it isn't unloaded in the middle of 3290 // a scan. 3291 cf->do_code_blob(_scanned_nmethod); 3292 } 3293 } 3294 3295 3296 // ======= Threads ======== 3297 3298 // The Threads class links together all active threads, and provides 3299 // operations over all threads. It is protected by its own Mutex 3300 // lock, which is also used in other contexts to protect thread 3301 // operations from having the thread being operated on from exiting 3302 // and going away unexpectedly (e.g., safepoint synchronization) 3303 3304 JavaThread* Threads::_thread_list = NULL; 3305 int Threads::_number_of_threads = 0; 3306 int Threads::_number_of_non_daemon_threads = 0; 3307 int Threads::_return_code = 0; 3308 int Threads::_thread_claim_parity = 0; 3309 size_t JavaThread::_stack_size_at_create = 0; 3310 #ifdef ASSERT 3311 bool Threads::_vm_complete = false; 3312 #endif 3313 3314 // All JavaThreads 3315 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3316 3317 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3318 void Threads::threads_do(ThreadClosure* tc) { 3319 assert_locked_or_safepoint(Threads_lock); 3320 // ALL_JAVA_THREADS iterates through all JavaThreads 3321 ALL_JAVA_THREADS(p) { 3322 tc->do_thread(p); 3323 } 3324 // Someday we could have a table or list of all non-JavaThreads. 3325 // For now, just manually iterate through them. 3326 tc->do_thread(VMThread::vm_thread()); 3327 Universe::heap()->gc_threads_do(tc); 3328 WatcherThread *wt = WatcherThread::watcher_thread(); 3329 // Strictly speaking, the following NULL check isn't sufficient to make sure 3330 // the data for WatcherThread is still valid upon being examined. However, 3331 // considering that WatchThread terminates when the VM is on the way to 3332 // exit at safepoint, the chance of the above is extremely small. The right 3333 // way to prevent termination of WatcherThread would be to acquire 3334 // Terminator_lock, but we can't do that without violating the lock rank 3335 // checking in some cases. 3336 if (wt != NULL) { 3337 tc->do_thread(wt); 3338 } 3339 3340 // If CompilerThreads ever become non-JavaThreads, add them here 3341 } 3342 3343 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3344 TraceStartupTime timer("Initialize java.lang classes"); 3345 3346 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3347 create_vm_init_libraries(); 3348 } 3349 3350 initialize_class(vmSymbols::java_lang_String(), CHECK); 3351 3352 // Inject CompactStrings value after the static initializers for String ran. 3353 java_lang_String::set_compact_strings(CompactStrings); 3354 3355 // Initialize java_lang.System (needed before creating the thread) 3356 initialize_class(vmSymbols::java_lang_System(), CHECK); 3357 // The VM creates & returns objects of this class. Make sure it's initialized. 3358 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3359 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3360 Handle thread_group = create_initial_thread_group(CHECK); 3361 Universe::set_main_thread_group(thread_group()); 3362 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3363 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3364 main_thread->set_threadObj(thread_object); 3365 // Set thread status to running since main thread has 3366 // been started and running. 3367 java_lang_Thread::set_thread_status(thread_object, 3368 java_lang_Thread::RUNNABLE); 3369 3370 // The VM preresolves methods to these classes. Make sure that they get initialized 3371 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3372 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3373 call_initializeSystemClass(CHECK); 3374 3375 // get the Java runtime name after java.lang.System is initialized 3376 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3377 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3378 3379 // an instance of OutOfMemory exception has been allocated earlier 3380 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3381 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3382 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3383 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3384 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3385 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3386 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3387 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3388 } 3389 3390 void Threads::initialize_jsr292_core_classes(TRAPS) { 3391 TraceStartupTime timer("Initialize java.lang.invoke classes"); 3392 3393 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3394 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3395 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3396 } 3397 3398 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3399 extern void JDK_Version_init(); 3400 3401 // Preinitialize version info. 3402 VM_Version::early_initialize(); 3403 3404 // Check version 3405 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3406 3407 // Initialize library-based TLS 3408 ThreadLocalStorage::init(); 3409 3410 // Initialize the output stream module 3411 ostream_init(); 3412 3413 // Process java launcher properties. 3414 Arguments::process_sun_java_launcher_properties(args); 3415 3416 // Initialize the os module 3417 os::init(); 3418 3419 // Record VM creation timing statistics 3420 TraceVmCreationTime create_vm_timer; 3421 create_vm_timer.start(); 3422 3423 // Initialize system properties. 3424 Arguments::init_system_properties(); 3425 3426 // So that JDK version can be used as a discriminator when parsing arguments 3427 JDK_Version_init(); 3428 3429 // Update/Initialize System properties after JDK version number is known 3430 Arguments::init_version_specific_system_properties(); 3431 3432 // Make sure to initialize log configuration *before* parsing arguments 3433 LogConfiguration::initialize(create_vm_timer.begin_time()); 3434 3435 // Parse arguments 3436 jint parse_result = Arguments::parse(args); 3437 if (parse_result != JNI_OK) return parse_result; 3438 3439 os::init_before_ergo(); 3440 3441 jint ergo_result = Arguments::apply_ergo(); 3442 if (ergo_result != JNI_OK) return ergo_result; 3443 3444 // Final check of all ranges after ergonomics which may change values. 3445 if (!CommandLineFlagRangeList::check_ranges()) { 3446 return JNI_EINVAL; 3447 } 3448 3449 // Final check of all 'AfterErgo' constraints after ergonomics which may change values. 3450 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo); 3451 if (!constraint_result) { 3452 return JNI_EINVAL; 3453 } 3454 3455 if (PauseAtStartup) { 3456 os::pause(); 3457 } 3458 3459 HOTSPOT_VM_INIT_BEGIN(); 3460 3461 // Timing (must come after argument parsing) 3462 TraceStartupTime timer("Create VM"); 3463 3464 // Initialize the os module after parsing the args 3465 jint os_init_2_result = os::init_2(); 3466 if (os_init_2_result != JNI_OK) return os_init_2_result; 3467 3468 jint adjust_after_os_result = Arguments::adjust_after_os(); 3469 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3470 3471 // Initialize output stream logging 3472 ostream_init_log(); 3473 3474 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3475 // Must be before create_vm_init_agents() 3476 if (Arguments::init_libraries_at_startup()) { 3477 convert_vm_init_libraries_to_agents(); 3478 } 3479 3480 // Launch -agentlib/-agentpath and converted -Xrun agents 3481 if (Arguments::init_agents_at_startup()) { 3482 create_vm_init_agents(); 3483 } 3484 3485 // Initialize Threads state 3486 _thread_list = NULL; 3487 _number_of_threads = 0; 3488 _number_of_non_daemon_threads = 0; 3489 3490 // Initialize global data structures and create system classes in heap 3491 vm_init_globals(); 3492 3493 #if INCLUDE_JVMCI 3494 if (JVMCICounterSize > 0) { 3495 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 3496 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize); 3497 } else { 3498 JavaThread::_jvmci_old_thread_counters = NULL; 3499 } 3500 #endif // INCLUDE_JVMCI 3501 3502 // Attach the main thread to this os thread 3503 JavaThread* main_thread = new JavaThread(); 3504 main_thread->set_thread_state(_thread_in_vm); 3505 main_thread->initialize_thread_current(); 3506 // must do this before set_active_handles 3507 main_thread->record_stack_base_and_size(); 3508 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3509 3510 if (!main_thread->set_as_starting_thread()) { 3511 vm_shutdown_during_initialization( 3512 "Failed necessary internal allocation. Out of swap space"); 3513 delete main_thread; 3514 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3515 return JNI_ENOMEM; 3516 } 3517 3518 // Enable guard page *after* os::create_main_thread(), otherwise it would 3519 // crash Linux VM, see notes in os_linux.cpp. 3520 main_thread->create_stack_guard_pages(); 3521 3522 // Initialize Java-Level synchronization subsystem 3523 ObjectMonitor::Initialize(); 3524 3525 // Initialize global modules 3526 jint status = init_globals(); 3527 if (status != JNI_OK) { 3528 delete main_thread; 3529 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3530 return status; 3531 } 3532 3533 // Should be done after the heap is fully created 3534 main_thread->cache_global_variables(); 3535 3536 HandleMark hm; 3537 3538 { MutexLocker mu(Threads_lock); 3539 Threads::add(main_thread); 3540 } 3541 3542 // Any JVMTI raw monitors entered in onload will transition into 3543 // real raw monitor. VM is setup enough here for raw monitor enter. 3544 JvmtiExport::transition_pending_onload_raw_monitors(); 3545 3546 // Create the VMThread 3547 { TraceStartupTime timer("Start VMThread"); 3548 3549 VMThread::create(); 3550 Thread* vmthread = VMThread::vm_thread(); 3551 3552 if (!os::create_thread(vmthread, os::vm_thread)) { 3553 vm_exit_during_initialization("Cannot create VM thread. " 3554 "Out of system resources."); 3555 } 3556 3557 // Wait for the VM thread to become ready, and VMThread::run to initialize 3558 // Monitors can have spurious returns, must always check another state flag 3559 { 3560 MutexLocker ml(Notify_lock); 3561 os::start_thread(vmthread); 3562 while (vmthread->active_handles() == NULL) { 3563 Notify_lock->wait(); 3564 } 3565 } 3566 } 3567 3568 assert(Universe::is_fully_initialized(), "not initialized"); 3569 if (VerifyDuringStartup) { 3570 // Make sure we're starting with a clean slate. 3571 VM_Verify verify_op; 3572 VMThread::execute(&verify_op); 3573 } 3574 3575 Thread* THREAD = Thread::current(); 3576 3577 // At this point, the Universe is initialized, but we have not executed 3578 // any byte code. Now is a good time (the only time) to dump out the 3579 // internal state of the JVM for sharing. 3580 if (DumpSharedSpaces) { 3581 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3582 ShouldNotReachHere(); 3583 } 3584 3585 // Always call even when there are not JVMTI environments yet, since environments 3586 // may be attached late and JVMTI must track phases of VM execution 3587 JvmtiExport::enter_start_phase(); 3588 3589 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3590 JvmtiExport::post_vm_start(); 3591 3592 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3593 3594 // We need this for ClassDataSharing - the initial vm.info property is set 3595 // with the default value of CDS "sharing" which may be reset through 3596 // command line options. 3597 reset_vm_info_property(CHECK_JNI_ERR); 3598 3599 quicken_jni_functions(); 3600 3601 // Must be run after init_ft which initializes ft_enabled 3602 if (TRACE_INITIALIZE() != JNI_OK) { 3603 vm_exit_during_initialization("Failed to initialize tracing backend"); 3604 } 3605 3606 // Set flag that basic initialization has completed. Used by exceptions and various 3607 // debug stuff, that does not work until all basic classes have been initialized. 3608 set_init_completed(); 3609 3610 LogConfiguration::post_initialize(); 3611 Metaspace::post_initialize(); 3612 3613 HOTSPOT_VM_INIT_END(); 3614 3615 // record VM initialization completion time 3616 #if INCLUDE_MANAGEMENT 3617 Management::record_vm_init_completed(); 3618 #endif // INCLUDE_MANAGEMENT 3619 3620 // Compute system loader. Note that this has to occur after set_init_completed, since 3621 // valid exceptions may be thrown in the process. 3622 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3623 // set_init_completed has just been called, causing exceptions not to be shortcut 3624 // anymore. We call vm_exit_during_initialization directly instead. 3625 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR)); 3626 3627 #if INCLUDE_ALL_GCS 3628 // Support for ConcurrentMarkSweep. This should be cleaned up 3629 // and better encapsulated. The ugly nested if test would go away 3630 // once things are properly refactored. XXX YSR 3631 if (UseConcMarkSweepGC || UseG1GC) { 3632 if (UseConcMarkSweepGC) { 3633 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3634 } else { 3635 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3636 } 3637 } 3638 #endif // INCLUDE_ALL_GCS 3639 3640 // Always call even when there are not JVMTI environments yet, since environments 3641 // may be attached late and JVMTI must track phases of VM execution 3642 JvmtiExport::enter_live_phase(); 3643 3644 // Signal Dispatcher needs to be started before VMInit event is posted 3645 os::signal_init(); 3646 3647 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3648 if (!DisableAttachMechanism) { 3649 AttachListener::vm_start(); 3650 if (StartAttachListener || AttachListener::init_at_startup()) { 3651 AttachListener::init(); 3652 } 3653 } 3654 3655 // Launch -Xrun agents 3656 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3657 // back-end can launch with -Xdebug -Xrunjdwp. 3658 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3659 create_vm_init_libraries(); 3660 } 3661 3662 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3663 JvmtiExport::post_vm_initialized(); 3664 3665 if (TRACE_START() != JNI_OK) { 3666 vm_exit_during_initialization("Failed to start tracing backend."); 3667 } 3668 3669 if (CleanChunkPoolAsync) { 3670 Chunk::start_chunk_pool_cleaner_task(); 3671 } 3672 3673 #if INCLUDE_JVMCI 3674 if (EnableJVMCI) { 3675 const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler"); 3676 if (jvmciCompiler != NULL) { 3677 JVMCIRuntime::save_compiler(jvmciCompiler); 3678 } 3679 } 3680 #endif // INCLUDE_JVMCI 3681 3682 // initialize compiler(s) 3683 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI 3684 CompileBroker::compilation_init(CHECK_JNI_ERR); 3685 #endif 3686 3687 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3688 // It is done after compilers are initialized, because otherwise compilations of 3689 // signature polymorphic MH intrinsics can be missed 3690 // (see SystemDictionary::find_method_handle_intrinsic). 3691 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3692 3693 #if INCLUDE_MANAGEMENT 3694 Management::initialize(THREAD); 3695 3696 if (HAS_PENDING_EXCEPTION) { 3697 // management agent fails to start possibly due to 3698 // configuration problem and is responsible for printing 3699 // stack trace if appropriate. Simply exit VM. 3700 vm_exit(1); 3701 } 3702 #endif // INCLUDE_MANAGEMENT 3703 3704 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3705 if (MemProfiling) MemProfiler::engage(); 3706 StatSampler::engage(); 3707 if (CheckJNICalls) JniPeriodicChecker::engage(); 3708 3709 BiasedLocking::init(); 3710 3711 #if INCLUDE_RTM_OPT 3712 RTMLockingCounters::init(); 3713 #endif 3714 3715 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3716 call_postVMInitHook(THREAD); 3717 // The Java side of PostVMInitHook.run must deal with all 3718 // exceptions and provide means of diagnosis. 3719 if (HAS_PENDING_EXCEPTION) { 3720 CLEAR_PENDING_EXCEPTION; 3721 } 3722 } 3723 3724 { 3725 MutexLocker ml(PeriodicTask_lock); 3726 // Make sure the WatcherThread can be started by WatcherThread::start() 3727 // or by dynamic enrollment. 3728 WatcherThread::make_startable(); 3729 // Start up the WatcherThread if there are any periodic tasks 3730 // NOTE: All PeriodicTasks should be registered by now. If they 3731 // aren't, late joiners might appear to start slowly (we might 3732 // take a while to process their first tick). 3733 if (PeriodicTask::num_tasks() > 0) { 3734 WatcherThread::start(); 3735 } 3736 } 3737 3738 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM); 3739 3740 create_vm_timer.end(); 3741 #ifdef ASSERT 3742 _vm_complete = true; 3743 #endif 3744 return JNI_OK; 3745 } 3746 3747 // type for the Agent_OnLoad and JVM_OnLoad entry points 3748 extern "C" { 3749 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3750 } 3751 // Find a command line agent library and return its entry point for 3752 // -agentlib: -agentpath: -Xrun 3753 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3754 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 3755 const char *on_load_symbols[], 3756 size_t num_symbol_entries) { 3757 OnLoadEntry_t on_load_entry = NULL; 3758 void *library = NULL; 3759 3760 if (!agent->valid()) { 3761 char buffer[JVM_MAXPATHLEN]; 3762 char ebuf[1024] = ""; 3763 const char *name = agent->name(); 3764 const char *msg = "Could not find agent library "; 3765 3766 // First check to see if agent is statically linked into executable 3767 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3768 library = agent->os_lib(); 3769 } else if (agent->is_absolute_path()) { 3770 library = os::dll_load(name, ebuf, sizeof ebuf); 3771 if (library == NULL) { 3772 const char *sub_msg = " in absolute path, with error: "; 3773 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3774 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3775 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3776 // If we can't find the agent, exit. 3777 vm_exit_during_initialization(buf, NULL); 3778 FREE_C_HEAP_ARRAY(char, buf); 3779 } 3780 } else { 3781 // Try to load the agent from the standard dll directory 3782 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3783 name)) { 3784 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3785 } 3786 if (library == NULL) { // Try the local directory 3787 char ns[1] = {0}; 3788 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3789 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3790 } 3791 if (library == NULL) { 3792 const char *sub_msg = " on the library path, with error: "; 3793 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3794 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3795 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3796 // If we can't find the agent, exit. 3797 vm_exit_during_initialization(buf, NULL); 3798 FREE_C_HEAP_ARRAY(char, buf); 3799 } 3800 } 3801 } 3802 agent->set_os_lib(library); 3803 agent->set_valid(); 3804 } 3805 3806 // Find the OnLoad function. 3807 on_load_entry = 3808 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3809 false, 3810 on_load_symbols, 3811 num_symbol_entries)); 3812 return on_load_entry; 3813 } 3814 3815 // Find the JVM_OnLoad entry point 3816 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3817 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3818 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3819 } 3820 3821 // Find the Agent_OnLoad entry point 3822 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3823 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3824 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3825 } 3826 3827 // For backwards compatibility with -Xrun 3828 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3829 // treated like -agentpath: 3830 // Must be called before agent libraries are created 3831 void Threads::convert_vm_init_libraries_to_agents() { 3832 AgentLibrary* agent; 3833 AgentLibrary* next; 3834 3835 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3836 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3837 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3838 3839 // If there is an JVM_OnLoad function it will get called later, 3840 // otherwise see if there is an Agent_OnLoad 3841 if (on_load_entry == NULL) { 3842 on_load_entry = lookup_agent_on_load(agent); 3843 if (on_load_entry != NULL) { 3844 // switch it to the agent list -- so that Agent_OnLoad will be called, 3845 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3846 Arguments::convert_library_to_agent(agent); 3847 } else { 3848 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3849 } 3850 } 3851 } 3852 } 3853 3854 // Create agents for -agentlib: -agentpath: and converted -Xrun 3855 // Invokes Agent_OnLoad 3856 // Called very early -- before JavaThreads exist 3857 void Threads::create_vm_init_agents() { 3858 extern struct JavaVM_ main_vm; 3859 AgentLibrary* agent; 3860 3861 JvmtiExport::enter_onload_phase(); 3862 3863 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3864 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3865 3866 if (on_load_entry != NULL) { 3867 // Invoke the Agent_OnLoad function 3868 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3869 if (err != JNI_OK) { 3870 vm_exit_during_initialization("agent library failed to init", agent->name()); 3871 } 3872 } else { 3873 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3874 } 3875 } 3876 JvmtiExport::enter_primordial_phase(); 3877 } 3878 3879 extern "C" { 3880 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3881 } 3882 3883 void Threads::shutdown_vm_agents() { 3884 // Send any Agent_OnUnload notifications 3885 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3886 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3887 extern struct JavaVM_ main_vm; 3888 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3889 3890 // Find the Agent_OnUnload function. 3891 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3892 os::find_agent_function(agent, 3893 false, 3894 on_unload_symbols, 3895 num_symbol_entries)); 3896 3897 // Invoke the Agent_OnUnload function 3898 if (unload_entry != NULL) { 3899 JavaThread* thread = JavaThread::current(); 3900 ThreadToNativeFromVM ttn(thread); 3901 HandleMark hm(thread); 3902 (*unload_entry)(&main_vm); 3903 } 3904 } 3905 } 3906 3907 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3908 // Invokes JVM_OnLoad 3909 void Threads::create_vm_init_libraries() { 3910 extern struct JavaVM_ main_vm; 3911 AgentLibrary* agent; 3912 3913 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3914 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3915 3916 if (on_load_entry != NULL) { 3917 // Invoke the JVM_OnLoad function 3918 JavaThread* thread = JavaThread::current(); 3919 ThreadToNativeFromVM ttn(thread); 3920 HandleMark hm(thread); 3921 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3922 if (err != JNI_OK) { 3923 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3924 } 3925 } else { 3926 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3927 } 3928 } 3929 } 3930 3931 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3932 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3933 3934 JavaThread* java_thread = NULL; 3935 // Sequential search for now. Need to do better optimization later. 3936 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3937 oop tobj = thread->threadObj(); 3938 if (!thread->is_exiting() && 3939 tobj != NULL && 3940 java_tid == java_lang_Thread::thread_id(tobj)) { 3941 java_thread = thread; 3942 break; 3943 } 3944 } 3945 return java_thread; 3946 } 3947 3948 3949 // Last thread running calls java.lang.Shutdown.shutdown() 3950 void JavaThread::invoke_shutdown_hooks() { 3951 HandleMark hm(this); 3952 3953 // We could get here with a pending exception, if so clear it now. 3954 if (this->has_pending_exception()) { 3955 this->clear_pending_exception(); 3956 } 3957 3958 EXCEPTION_MARK; 3959 Klass* k = 3960 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3961 THREAD); 3962 if (k != NULL) { 3963 // SystemDictionary::resolve_or_null will return null if there was 3964 // an exception. If we cannot load the Shutdown class, just don't 3965 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3966 // and finalizers (if runFinalizersOnExit is set) won't be run. 3967 // Note that if a shutdown hook was registered or runFinalizersOnExit 3968 // was called, the Shutdown class would have already been loaded 3969 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3970 instanceKlassHandle shutdown_klass (THREAD, k); 3971 JavaValue result(T_VOID); 3972 JavaCalls::call_static(&result, 3973 shutdown_klass, 3974 vmSymbols::shutdown_method_name(), 3975 vmSymbols::void_method_signature(), 3976 THREAD); 3977 } 3978 CLEAR_PENDING_EXCEPTION; 3979 } 3980 3981 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3982 // the program falls off the end of main(). Another VM exit path is through 3983 // vm_exit() when the program calls System.exit() to return a value or when 3984 // there is a serious error in VM. The two shutdown paths are not exactly 3985 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3986 // and VM_Exit op at VM level. 3987 // 3988 // Shutdown sequence: 3989 // + Shutdown native memory tracking if it is on 3990 // + Wait until we are the last non-daemon thread to execute 3991 // <-- every thing is still working at this moment --> 3992 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3993 // shutdown hooks, run finalizers if finalization-on-exit 3994 // + Call before_exit(), prepare for VM exit 3995 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3996 // currently the only user of this mechanism is File.deleteOnExit()) 3997 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3998 // post thread end and vm death events to JVMTI, 3999 // stop signal thread 4000 // + Call JavaThread::exit(), it will: 4001 // > release JNI handle blocks, remove stack guard pages 4002 // > remove this thread from Threads list 4003 // <-- no more Java code from this thread after this point --> 4004 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 4005 // the compiler threads at safepoint 4006 // <-- do not use anything that could get blocked by Safepoint --> 4007 // + Disable tracing at JNI/JVM barriers 4008 // + Set _vm_exited flag for threads that are still running native code 4009 // + Delete this thread 4010 // + Call exit_globals() 4011 // > deletes tty 4012 // > deletes PerfMemory resources 4013 // + Return to caller 4014 4015 bool Threads::destroy_vm() { 4016 JavaThread* thread = JavaThread::current(); 4017 4018 #ifdef ASSERT 4019 _vm_complete = false; 4020 #endif 4021 // Wait until we are the last non-daemon thread to execute 4022 { MutexLocker nu(Threads_lock); 4023 while (Threads::number_of_non_daemon_threads() > 1) 4024 // This wait should make safepoint checks, wait without a timeout, 4025 // and wait as a suspend-equivalent condition. 4026 // 4027 // Note: If the FlatProfiler is running and this thread is waiting 4028 // for another non-daemon thread to finish, then the FlatProfiler 4029 // is waiting for the external suspend request on this thread to 4030 // complete. wait_for_ext_suspend_completion() will eventually 4031 // timeout, but that takes time. Making this wait a suspend- 4032 // equivalent condition solves that timeout problem. 4033 // 4034 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 4035 Mutex::_as_suspend_equivalent_flag); 4036 } 4037 4038 // Hang forever on exit if we are reporting an error. 4039 if (ShowMessageBoxOnError && is_error_reported()) { 4040 os::infinite_sleep(); 4041 } 4042 os::wait_for_keypress_at_exit(); 4043 4044 // run Java level shutdown hooks 4045 thread->invoke_shutdown_hooks(); 4046 4047 before_exit(thread); 4048 4049 thread->exit(true); 4050 4051 // Stop VM thread. 4052 { 4053 // 4945125 The vm thread comes to a safepoint during exit. 4054 // GC vm_operations can get caught at the safepoint, and the 4055 // heap is unparseable if they are caught. Grab the Heap_lock 4056 // to prevent this. The GC vm_operations will not be able to 4057 // queue until after the vm thread is dead. After this point, 4058 // we'll never emerge out of the safepoint before the VM exits. 4059 4060 MutexLocker ml(Heap_lock); 4061 4062 VMThread::wait_for_vm_thread_exit(); 4063 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4064 VMThread::destroy(); 4065 } 4066 4067 // clean up ideal graph printers 4068 #if defined(COMPILER2) && !defined(PRODUCT) 4069 IdealGraphPrinter::clean_up(); 4070 #endif 4071 4072 // Now, all Java threads are gone except daemon threads. Daemon threads 4073 // running Java code or in VM are stopped by the Safepoint. However, 4074 // daemon threads executing native code are still running. But they 4075 // will be stopped at native=>Java/VM barriers. Note that we can't 4076 // simply kill or suspend them, as it is inherently deadlock-prone. 4077 4078 VM_Exit::set_vm_exited(); 4079 4080 notify_vm_shutdown(); 4081 4082 delete thread; 4083 4084 #if INCLUDE_JVMCI 4085 if (JVMCICounterSize > 0) { 4086 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters); 4087 } 4088 #endif 4089 4090 // exit_globals() will delete tty 4091 exit_globals(); 4092 4093 LogConfiguration::finalize(); 4094 4095 return true; 4096 } 4097 4098 4099 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4100 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4101 return is_supported_jni_version(version); 4102 } 4103 4104 4105 jboolean Threads::is_supported_jni_version(jint version) { 4106 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4107 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4108 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4109 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4110 return JNI_FALSE; 4111 } 4112 4113 4114 void Threads::add(JavaThread* p, bool force_daemon) { 4115 // The threads lock must be owned at this point 4116 assert_locked_or_safepoint(Threads_lock); 4117 4118 // See the comment for this method in thread.hpp for its purpose and 4119 // why it is called here. 4120 p->initialize_queues(); 4121 p->set_next(_thread_list); 4122 _thread_list = p; 4123 _number_of_threads++; 4124 oop threadObj = p->threadObj(); 4125 bool daemon = true; 4126 // Bootstrapping problem: threadObj can be null for initial 4127 // JavaThread (or for threads attached via JNI) 4128 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4129 _number_of_non_daemon_threads++; 4130 daemon = false; 4131 } 4132 4133 ThreadService::add_thread(p, daemon); 4134 4135 // Possible GC point. 4136 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p)); 4137 } 4138 4139 void Threads::remove(JavaThread* p) { 4140 // Extra scope needed for Thread_lock, so we can check 4141 // that we do not remove thread without safepoint code notice 4142 { MutexLocker ml(Threads_lock); 4143 4144 assert(includes(p), "p must be present"); 4145 4146 JavaThread* current = _thread_list; 4147 JavaThread* prev = NULL; 4148 4149 while (current != p) { 4150 prev = current; 4151 current = current->next(); 4152 } 4153 4154 if (prev) { 4155 prev->set_next(current->next()); 4156 } else { 4157 _thread_list = p->next(); 4158 } 4159 _number_of_threads--; 4160 oop threadObj = p->threadObj(); 4161 bool daemon = true; 4162 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4163 _number_of_non_daemon_threads--; 4164 daemon = false; 4165 4166 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4167 // on destroy_vm will wake up. 4168 if (number_of_non_daemon_threads() == 1) { 4169 Threads_lock->notify_all(); 4170 } 4171 } 4172 ThreadService::remove_thread(p, daemon); 4173 4174 // Make sure that safepoint code disregard this thread. This is needed since 4175 // the thread might mess around with locks after this point. This can cause it 4176 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4177 // of this thread since it is removed from the queue. 4178 p->set_terminated_value(); 4179 } // unlock Threads_lock 4180 4181 // Since Events::log uses a lock, we grab it outside the Threads_lock 4182 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p)); 4183 } 4184 4185 // Threads_lock must be held when this is called (or must be called during a safepoint) 4186 bool Threads::includes(JavaThread* p) { 4187 assert(Threads_lock->is_locked(), "sanity check"); 4188 ALL_JAVA_THREADS(q) { 4189 if (q == p) { 4190 return true; 4191 } 4192 } 4193 return false; 4194 } 4195 4196 // Operations on the Threads list for GC. These are not explicitly locked, 4197 // but the garbage collector must provide a safe context for them to run. 4198 // In particular, these things should never be called when the Threads_lock 4199 // is held by some other thread. (Note: the Safepoint abstraction also 4200 // uses the Threads_lock to guarantee this property. It also makes sure that 4201 // all threads gets blocked when exiting or starting). 4202 4203 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4204 ALL_JAVA_THREADS(p) { 4205 p->oops_do(f, cld_f, cf); 4206 } 4207 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4208 } 4209 4210 void Threads::change_thread_claim_parity() { 4211 // Set the new claim parity. 4212 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2, 4213 "Not in range."); 4214 _thread_claim_parity++; 4215 if (_thread_claim_parity == 3) _thread_claim_parity = 1; 4216 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2, 4217 "Not in range."); 4218 } 4219 4220 #ifdef ASSERT 4221 void Threads::assert_all_threads_claimed() { 4222 ALL_JAVA_THREADS(p) { 4223 const int thread_parity = p->oops_do_parity(); 4224 assert((thread_parity == _thread_claim_parity), 4225 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity); 4226 } 4227 } 4228 #endif // ASSERT 4229 4230 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4231 int cp = Threads::thread_claim_parity(); 4232 ALL_JAVA_THREADS(p) { 4233 if (p->claim_oops_do(is_par, cp)) { 4234 p->oops_do(f, cld_f, cf); 4235 } 4236 } 4237 VMThread* vmt = VMThread::vm_thread(); 4238 if (vmt->claim_oops_do(is_par, cp)) { 4239 vmt->oops_do(f, cld_f, cf); 4240 } 4241 } 4242 4243 #if INCLUDE_ALL_GCS 4244 // Used by ParallelScavenge 4245 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4246 ALL_JAVA_THREADS(p) { 4247 q->enqueue(new ThreadRootsTask(p)); 4248 } 4249 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4250 } 4251 4252 // Used by Parallel Old 4253 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4254 ALL_JAVA_THREADS(p) { 4255 q->enqueue(new ThreadRootsMarkingTask(p)); 4256 } 4257 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4258 } 4259 #endif // INCLUDE_ALL_GCS 4260 4261 void Threads::nmethods_do(CodeBlobClosure* cf) { 4262 ALL_JAVA_THREADS(p) { 4263 p->nmethods_do(cf); 4264 } 4265 VMThread::vm_thread()->nmethods_do(cf); 4266 } 4267 4268 void Threads::metadata_do(void f(Metadata*)) { 4269 ALL_JAVA_THREADS(p) { 4270 p->metadata_do(f); 4271 } 4272 } 4273 4274 class ThreadHandlesClosure : public ThreadClosure { 4275 void (*_f)(Metadata*); 4276 public: 4277 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4278 virtual void do_thread(Thread* thread) { 4279 thread->metadata_handles_do(_f); 4280 } 4281 }; 4282 4283 void Threads::metadata_handles_do(void f(Metadata*)) { 4284 // Only walk the Handles in Thread. 4285 ThreadHandlesClosure handles_closure(f); 4286 threads_do(&handles_closure); 4287 } 4288 4289 void Threads::deoptimized_wrt_marked_nmethods() { 4290 ALL_JAVA_THREADS(p) { 4291 p->deoptimized_wrt_marked_nmethods(); 4292 } 4293 } 4294 4295 4296 // Get count Java threads that are waiting to enter the specified monitor. 4297 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4298 address monitor, 4299 bool doLock) { 4300 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4301 "must grab Threads_lock or be at safepoint"); 4302 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4303 4304 int i = 0; 4305 { 4306 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4307 ALL_JAVA_THREADS(p) { 4308 if (!p->can_call_java()) continue; 4309 4310 address pending = (address)p->current_pending_monitor(); 4311 if (pending == monitor) { // found a match 4312 if (i < count) result->append(p); // save the first count matches 4313 i++; 4314 } 4315 } 4316 } 4317 return result; 4318 } 4319 4320 4321 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, 4322 bool doLock) { 4323 assert(doLock || 4324 Threads_lock->owned_by_self() || 4325 SafepointSynchronize::is_at_safepoint(), 4326 "must grab Threads_lock or be at safepoint"); 4327 4328 // NULL owner means not locked so we can skip the search 4329 if (owner == NULL) return NULL; 4330 4331 { 4332 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4333 ALL_JAVA_THREADS(p) { 4334 // first, see if owner is the address of a Java thread 4335 if (owner == (address)p) return p; 4336 } 4337 } 4338 // Cannot assert on lack of success here since this function may be 4339 // used by code that is trying to report useful problem information 4340 // like deadlock detection. 4341 if (UseHeavyMonitors) return NULL; 4342 4343 // If we didn't find a matching Java thread and we didn't force use of 4344 // heavyweight monitors, then the owner is the stack address of the 4345 // Lock Word in the owning Java thread's stack. 4346 // 4347 JavaThread* the_owner = NULL; 4348 { 4349 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4350 ALL_JAVA_THREADS(q) { 4351 if (q->is_lock_owned(owner)) { 4352 the_owner = q; 4353 break; 4354 } 4355 } 4356 } 4357 // cannot assert on lack of success here; see above comment 4358 return the_owner; 4359 } 4360 4361 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4362 void Threads::print_on(outputStream* st, bool print_stacks, 4363 bool internal_format, bool print_concurrent_locks) { 4364 char buf[32]; 4365 st->print_raw_cr(os::local_time_string(buf, sizeof(buf))); 4366 4367 st->print_cr("Full thread dump %s (%s %s):", 4368 Abstract_VM_Version::vm_name(), 4369 Abstract_VM_Version::vm_release(), 4370 Abstract_VM_Version::vm_info_string()); 4371 st->cr(); 4372 4373 #if INCLUDE_SERVICES 4374 // Dump concurrent locks 4375 ConcurrentLocksDump concurrent_locks; 4376 if (print_concurrent_locks) { 4377 concurrent_locks.dump_at_safepoint(); 4378 } 4379 #endif // INCLUDE_SERVICES 4380 4381 ALL_JAVA_THREADS(p) { 4382 ResourceMark rm; 4383 p->print_on(st); 4384 if (print_stacks) { 4385 if (internal_format) { 4386 p->trace_stack(); 4387 } else { 4388 p->print_stack_on(st); 4389 } 4390 } 4391 st->cr(); 4392 #if INCLUDE_SERVICES 4393 if (print_concurrent_locks) { 4394 concurrent_locks.print_locks_on(p, st); 4395 } 4396 #endif // INCLUDE_SERVICES 4397 } 4398 4399 VMThread::vm_thread()->print_on(st); 4400 st->cr(); 4401 Universe::heap()->print_gc_threads_on(st); 4402 WatcherThread* wt = WatcherThread::watcher_thread(); 4403 if (wt != NULL) { 4404 wt->print_on(st); 4405 st->cr(); 4406 } 4407 st->flush(); 4408 } 4409 4410 // Threads::print_on_error() is called by fatal error handler. It's possible 4411 // that VM is not at safepoint and/or current thread is inside signal handler. 4412 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4413 // memory (even in resource area), it might deadlock the error handler. 4414 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4415 int buflen) { 4416 bool found_current = false; 4417 st->print_cr("Java Threads: ( => current thread )"); 4418 ALL_JAVA_THREADS(thread) { 4419 bool is_current = (current == thread); 4420 found_current = found_current || is_current; 4421 4422 st->print("%s", is_current ? "=>" : " "); 4423 4424 st->print(PTR_FORMAT, p2i(thread)); 4425 st->print(" "); 4426 thread->print_on_error(st, buf, buflen); 4427 st->cr(); 4428 } 4429 st->cr(); 4430 4431 st->print_cr("Other Threads:"); 4432 if (VMThread::vm_thread()) { 4433 bool is_current = (current == VMThread::vm_thread()); 4434 found_current = found_current || is_current; 4435 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4436 4437 st->print(PTR_FORMAT, p2i(VMThread::vm_thread())); 4438 st->print(" "); 4439 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4440 st->cr(); 4441 } 4442 WatcherThread* wt = WatcherThread::watcher_thread(); 4443 if (wt != NULL) { 4444 bool is_current = (current == wt); 4445 found_current = found_current || is_current; 4446 st->print("%s", is_current ? "=>" : " "); 4447 4448 st->print(PTR_FORMAT, p2i(wt)); 4449 st->print(" "); 4450 wt->print_on_error(st, buf, buflen); 4451 st->cr(); 4452 } 4453 if (!found_current) { 4454 st->cr(); 4455 st->print("=>" PTR_FORMAT " (exited) ", p2i(current)); 4456 current->print_on_error(st, buf, buflen); 4457 st->cr(); 4458 } 4459 st->cr(); 4460 st->print_cr("Threads with active compile tasks:"); 4461 print_threads_compiling(st, buf, buflen); 4462 } 4463 4464 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) { 4465 ALL_JAVA_THREADS(thread) { 4466 if (thread->is_Compiler_thread()) { 4467 CompilerThread* ct = (CompilerThread*) thread; 4468 if (ct->task() != NULL) { 4469 thread->print_name_on_error(st, buf, buflen); 4470 ct->task()->print(st, NULL, true, true); 4471 } 4472 } 4473 } 4474 } 4475 4476 4477 // Internal SpinLock and Mutex 4478 // Based on ParkEvent 4479 4480 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4481 // 4482 // We employ SpinLocks _only for low-contention, fixed-length 4483 // short-duration critical sections where we're concerned 4484 // about native mutex_t or HotSpot Mutex:: latency. 4485 // The mux construct provides a spin-then-block mutual exclusion 4486 // mechanism. 4487 // 4488 // Testing has shown that contention on the ListLock guarding gFreeList 4489 // is common. If we implement ListLock as a simple SpinLock it's common 4490 // for the JVM to devolve to yielding with little progress. This is true 4491 // despite the fact that the critical sections protected by ListLock are 4492 // extremely short. 4493 // 4494 // TODO-FIXME: ListLock should be of type SpinLock. 4495 // We should make this a 1st-class type, integrated into the lock 4496 // hierarchy as leaf-locks. Critically, the SpinLock structure 4497 // should have sufficient padding to avoid false-sharing and excessive 4498 // cache-coherency traffic. 4499 4500 4501 typedef volatile int SpinLockT; 4502 4503 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4504 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4505 return; // normal fast-path return 4506 } 4507 4508 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4509 TEVENT(SpinAcquire - ctx); 4510 int ctr = 0; 4511 int Yields = 0; 4512 for (;;) { 4513 while (*adr != 0) { 4514 ++ctr; 4515 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4516 if (Yields > 5) { 4517 os::naked_short_sleep(1); 4518 } else { 4519 os::naked_yield(); 4520 ++Yields; 4521 } 4522 } else { 4523 SpinPause(); 4524 } 4525 } 4526 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4527 } 4528 } 4529 4530 void Thread::SpinRelease(volatile int * adr) { 4531 assert(*adr != 0, "invariant"); 4532 OrderAccess::fence(); // guarantee at least release consistency. 4533 // Roach-motel semantics. 4534 // It's safe if subsequent LDs and STs float "up" into the critical section, 4535 // but prior LDs and STs within the critical section can't be allowed 4536 // to reorder or float past the ST that releases the lock. 4537 // Loads and stores in the critical section - which appear in program 4538 // order before the store that releases the lock - must also appear 4539 // before the store that releases the lock in memory visibility order. 4540 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4541 // the ST of 0 into the lock-word which releases the lock, so fence 4542 // more than covers this on all platforms. 4543 *adr = 0; 4544 } 4545 4546 // muxAcquire and muxRelease: 4547 // 4548 // * muxAcquire and muxRelease support a single-word lock-word construct. 4549 // The LSB of the word is set IFF the lock is held. 4550 // The remainder of the word points to the head of a singly-linked list 4551 // of threads blocked on the lock. 4552 // 4553 // * The current implementation of muxAcquire-muxRelease uses its own 4554 // dedicated Thread._MuxEvent instance. If we're interested in 4555 // minimizing the peak number of extant ParkEvent instances then 4556 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4557 // as certain invariants were satisfied. Specifically, care would need 4558 // to be taken with regards to consuming unpark() "permits". 4559 // A safe rule of thumb is that a thread would never call muxAcquire() 4560 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4561 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4562 // consume an unpark() permit intended for monitorenter, for instance. 4563 // One way around this would be to widen the restricted-range semaphore 4564 // implemented in park(). Another alternative would be to provide 4565 // multiple instances of the PlatformEvent() for each thread. One 4566 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4567 // 4568 // * Usage: 4569 // -- Only as leaf locks 4570 // -- for short-term locking only as muxAcquire does not perform 4571 // thread state transitions. 4572 // 4573 // Alternatives: 4574 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4575 // but with parking or spin-then-park instead of pure spinning. 4576 // * Use Taura-Oyama-Yonenzawa locks. 4577 // * It's possible to construct a 1-0 lock if we encode the lockword as 4578 // (List,LockByte). Acquire will CAS the full lockword while Release 4579 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4580 // acquiring threads use timers (ParkTimed) to detect and recover from 4581 // the stranding window. Thread/Node structures must be aligned on 256-byte 4582 // boundaries by using placement-new. 4583 // * Augment MCS with advisory back-link fields maintained with CAS(). 4584 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4585 // The validity of the backlinks must be ratified before we trust the value. 4586 // If the backlinks are invalid the exiting thread must back-track through the 4587 // the forward links, which are always trustworthy. 4588 // * Add a successor indication. The LockWord is currently encoded as 4589 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4590 // to provide the usual futile-wakeup optimization. 4591 // See RTStt for details. 4592 // * Consider schedctl.sc_nopreempt to cover the critical section. 4593 // 4594 4595 4596 typedef volatile intptr_t MutexT; // Mux Lock-word 4597 enum MuxBits { LOCKBIT = 1 }; 4598 4599 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4600 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4601 if (w == 0) return; 4602 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4603 return; 4604 } 4605 4606 TEVENT(muxAcquire - Contention); 4607 ParkEvent * const Self = Thread::current()->_MuxEvent; 4608 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4609 for (;;) { 4610 int its = (os::is_MP() ? 100 : 0) + 1; 4611 4612 // Optional spin phase: spin-then-park strategy 4613 while (--its >= 0) { 4614 w = *Lock; 4615 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4616 return; 4617 } 4618 } 4619 4620 Self->reset(); 4621 Self->OnList = intptr_t(Lock); 4622 // The following fence() isn't _strictly necessary as the subsequent 4623 // CAS() both serializes execution and ratifies the fetched *Lock value. 4624 OrderAccess::fence(); 4625 for (;;) { 4626 w = *Lock; 4627 if ((w & LOCKBIT) == 0) { 4628 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4629 Self->OnList = 0; // hygiene - allows stronger asserts 4630 return; 4631 } 4632 continue; // Interference -- *Lock changed -- Just retry 4633 } 4634 assert(w & LOCKBIT, "invariant"); 4635 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4636 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4637 } 4638 4639 while (Self->OnList != 0) { 4640 Self->park(); 4641 } 4642 } 4643 } 4644 4645 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4646 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4647 if (w == 0) return; 4648 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4649 return; 4650 } 4651 4652 TEVENT(muxAcquire - Contention); 4653 ParkEvent * ReleaseAfter = NULL; 4654 if (ev == NULL) { 4655 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4656 } 4657 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4658 for (;;) { 4659 guarantee(ev->OnList == 0, "invariant"); 4660 int its = (os::is_MP() ? 100 : 0) + 1; 4661 4662 // Optional spin phase: spin-then-park strategy 4663 while (--its >= 0) { 4664 w = *Lock; 4665 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4666 if (ReleaseAfter != NULL) { 4667 ParkEvent::Release(ReleaseAfter); 4668 } 4669 return; 4670 } 4671 } 4672 4673 ev->reset(); 4674 ev->OnList = intptr_t(Lock); 4675 // The following fence() isn't _strictly necessary as the subsequent 4676 // CAS() both serializes execution and ratifies the fetched *Lock value. 4677 OrderAccess::fence(); 4678 for (;;) { 4679 w = *Lock; 4680 if ((w & LOCKBIT) == 0) { 4681 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4682 ev->OnList = 0; 4683 // We call ::Release while holding the outer lock, thus 4684 // artificially lengthening the critical section. 4685 // Consider deferring the ::Release() until the subsequent unlock(), 4686 // after we've dropped the outer lock. 4687 if (ReleaseAfter != NULL) { 4688 ParkEvent::Release(ReleaseAfter); 4689 } 4690 return; 4691 } 4692 continue; // Interference -- *Lock changed -- Just retry 4693 } 4694 assert(w & LOCKBIT, "invariant"); 4695 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4696 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4697 } 4698 4699 while (ev->OnList != 0) { 4700 ev->park(); 4701 } 4702 } 4703 } 4704 4705 // Release() must extract a successor from the list and then wake that thread. 4706 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4707 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4708 // Release() would : 4709 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4710 // (B) Extract a successor from the private list "in-hand" 4711 // (C) attempt to CAS() the residual back into *Lock over null. 4712 // If there were any newly arrived threads and the CAS() would fail. 4713 // In that case Release() would detach the RATs, re-merge the list in-hand 4714 // with the RATs and repeat as needed. Alternately, Release() might 4715 // detach and extract a successor, but then pass the residual list to the wakee. 4716 // The wakee would be responsible for reattaching and remerging before it 4717 // competed for the lock. 4718 // 4719 // Both "pop" and DMR are immune from ABA corruption -- there can be 4720 // multiple concurrent pushers, but only one popper or detacher. 4721 // This implementation pops from the head of the list. This is unfair, 4722 // but tends to provide excellent throughput as hot threads remain hot. 4723 // (We wake recently run threads first). 4724 // 4725 // All paths through muxRelease() will execute a CAS. 4726 // Release consistency -- We depend on the CAS in muxRelease() to provide full 4727 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4728 // executed within the critical section are complete and globally visible before the 4729 // store (CAS) to the lock-word that releases the lock becomes globally visible. 4730 void Thread::muxRelease(volatile intptr_t * Lock) { 4731 for (;;) { 4732 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4733 assert(w & LOCKBIT, "invariant"); 4734 if (w == LOCKBIT) return; 4735 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4736 assert(List != NULL, "invariant"); 4737 assert(List->OnList == intptr_t(Lock), "invariant"); 4738 ParkEvent * const nxt = List->ListNext; 4739 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4740 4741 // The following CAS() releases the lock and pops the head element. 4742 // The CAS() also ratifies the previously fetched lock-word value. 4743 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4744 continue; 4745 } 4746 List->OnList = 0; 4747 OrderAccess::fence(); 4748 List->unpark(); 4749 return; 4750 } 4751 } 4752 4753 4754 void Threads::verify() { 4755 ALL_JAVA_THREADS(p) { 4756 p->verify(); 4757 } 4758 VMThread* thread = VMThread::vm_thread(); 4759 if (thread != NULL) thread->verify(); 4760 }