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/scopeDesc.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "interpreter/interpreter.hpp" 33 #include "interpreter/linkResolver.hpp" 34 #include "interpreter/oopMapCache.hpp" 35 #include "jvmtifiles/jvmtiEnv.hpp" 36 #include "memory/gcLocker.inline.hpp" 37 #include "memory/metaspaceShared.hpp" 38 #include "memory/oopFactory.hpp" 39 #include "memory/universe.inline.hpp" 40 #include "oops/instanceKlass.hpp" 41 #include "oops/objArrayOop.hpp" 42 #include "oops/oop.inline.hpp" 43 #include "oops/symbol.hpp" 44 #include "prims/jvm_misc.hpp" 45 #include "prims/jvmtiExport.hpp" 46 #include "prims/jvmtiThreadState.hpp" 47 #include "prims/privilegedStack.hpp" 48 #include "runtime/arguments.hpp" 49 #include "runtime/biasedLocking.hpp" 50 #include "runtime/deoptimization.hpp" 51 #include "runtime/fprofiler.hpp" 52 #include "runtime/frame.inline.hpp" 53 #include "runtime/init.hpp" 54 #include "runtime/interfaceSupport.hpp" 55 #include "runtime/java.hpp" 56 #include "runtime/javaCalls.hpp" 57 #include "runtime/jniPeriodicChecker.hpp" 58 #include "runtime/memprofiler.hpp" 59 #include "runtime/mutexLocker.hpp" 60 #include "runtime/objectMonitor.hpp" 61 #include "runtime/orderAccess.inline.hpp" 62 #include "runtime/osThread.hpp" 63 #include "runtime/safepoint.hpp" 64 #include "runtime/sharedRuntime.hpp" 65 #include "runtime/statSampler.hpp" 66 #include "runtime/stubRoutines.hpp" 67 #include "runtime/task.hpp" 68 #include "runtime/thread.inline.hpp" 69 #include "runtime/threadCritical.hpp" 70 #include "runtime/threadLocalStorage.hpp" 71 #include "runtime/vframe.hpp" 72 #include "runtime/vframeArray.hpp" 73 #include "runtime/vframe_hp.hpp" 74 #include "runtime/vmThread.hpp" 75 #include "runtime/vm_operations.hpp" 76 #include "services/attachListener.hpp" 77 #include "services/management.hpp" 78 #include "services/memTracker.hpp" 79 #include "services/threadService.hpp" 80 #include "trace/tracing.hpp" 81 #include "trace/traceMacros.hpp" 82 #include "utilities/defaultStream.hpp" 83 #include "utilities/dtrace.hpp" 84 #include "utilities/events.hpp" 85 #include "utilities/preserveException.hpp" 86 #include "utilities/macros.hpp" 87 #ifdef TARGET_OS_FAMILY_linux 88 # include "os_linux.inline.hpp" 89 #endif 90 #ifdef TARGET_OS_FAMILY_solaris 91 # include "os_solaris.inline.hpp" 92 #endif 93 #ifdef TARGET_OS_FAMILY_windows 94 # include "os_windows.inline.hpp" 95 #endif 96 #ifdef TARGET_OS_FAMILY_bsd 97 # include "os_bsd.inline.hpp" 98 #endif 99 #if INCLUDE_ALL_GCS 100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 102 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 103 #endif // INCLUDE_ALL_GCS 104 #ifdef COMPILER1 105 #include "c1/c1_Compiler.hpp" 106 #endif 107 #ifdef COMPILER2 108 #include "opto/c2compiler.hpp" 109 #include "opto/idealGraphPrinter.hpp" 110 #endif 111 #if INCLUDE_RTM_OPT 112 #include "runtime/rtmLocking.hpp" 113 #endif 114 115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 116 117 #ifdef DTRACE_ENABLED 118 119 // Only bother with this argument setup if dtrace is available 120 121 #ifndef USDT2 122 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 123 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 124 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 125 intptr_t, intptr_t, bool); 126 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 127 intptr_t, intptr_t, bool); 128 129 #define DTRACE_THREAD_PROBE(probe, javathread) \ 130 { \ 131 ResourceMark rm(this); \ 132 int len = 0; \ 133 const char* name = (javathread)->get_thread_name(); \ 134 len = strlen(name); \ 135 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 136 name, len, \ 137 java_lang_Thread::thread_id((javathread)->threadObj()), \ 138 (javathread)->osthread()->thread_id(), \ 139 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 140 } 141 142 #else /* USDT2 */ 143 144 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 145 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 146 147 #define DTRACE_THREAD_PROBE(probe, javathread) \ 148 { \ 149 ResourceMark rm(this); \ 150 int len = 0; \ 151 const char* name = (javathread)->get_thread_name(); \ 152 len = strlen(name); \ 153 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 154 (char *) name, len, \ 155 java_lang_Thread::thread_id((javathread)->threadObj()), \ 156 (uintptr_t) (javathread)->osthread()->thread_id(), \ 157 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 158 } 159 160 #endif /* USDT2 */ 161 162 #else // ndef DTRACE_ENABLED 163 164 #define DTRACE_THREAD_PROBE(probe, javathread) 165 166 #endif // ndef DTRACE_ENABLED 167 168 169 // Class hierarchy 170 // - Thread 171 // - VMThread 172 // - WatcherThread 173 // - ConcurrentMarkSweepThread 174 // - JavaThread 175 // - CompilerThread 176 177 // ======= Thread ======== 178 // Support for forcing alignment of thread objects for biased locking 179 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 180 if (UseBiasedLocking) { 181 const int alignment = markOopDesc::biased_lock_alignment; 182 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 183 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 184 : AllocateHeap(aligned_size, flags, CURRENT_PC, 185 AllocFailStrategy::RETURN_NULL); 186 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 187 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 188 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 189 "JavaThread alignment code overflowed allocated storage"); 190 if (TraceBiasedLocking) { 191 if (aligned_addr != real_malloc_addr) 192 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 193 real_malloc_addr, aligned_addr); 194 } 195 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 196 return aligned_addr; 197 } else { 198 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 199 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 200 } 201 } 202 203 void Thread::operator delete(void* p) { 204 if (UseBiasedLocking) { 205 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 206 FreeHeap(real_malloc_addr, mtThread); 207 } else { 208 FreeHeap(p, mtThread); 209 } 210 } 211 212 213 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 214 // JavaThread 215 216 217 Thread::Thread() { 218 // stack and get_thread 219 set_stack_base(NULL); 220 set_stack_size(0); 221 set_self_raw_id(0); 222 set_lgrp_id(-1); 223 224 // allocated data structures 225 set_osthread(NULL); 226 set_resource_area(new (mtThread)ResourceArea()); 227 DEBUG_ONLY(_current_resource_mark = NULL;) 228 set_handle_area(new (mtThread) HandleArea(NULL)); 229 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 230 set_active_handles(NULL); 231 set_free_handle_block(NULL); 232 set_last_handle_mark(NULL); 233 234 // This initial value ==> never claimed. 235 _oops_do_parity = 0; 236 237 _metadata_on_stack_buffer = NULL; 238 239 // the handle mark links itself to last_handle_mark 240 new HandleMark(this); 241 242 // plain initialization 243 debug_only(_owned_locks = NULL;) 244 debug_only(_allow_allocation_count = 0;) 245 NOT_PRODUCT(_allow_safepoint_count = 0;) 246 NOT_PRODUCT(_skip_gcalot = false;) 247 _jvmti_env_iteration_count = 0; 248 set_allocated_bytes(0); 249 _vm_operation_started_count = 0; 250 _vm_operation_completed_count = 0; 251 _current_pending_monitor = NULL; 252 _current_pending_monitor_is_from_java = true; 253 _current_waiting_monitor = NULL; 254 _num_nested_signal = 0; 255 omFreeList = NULL ; 256 omFreeCount = 0 ; 257 omFreeProvision = 32 ; 258 omInUseList = NULL ; 259 omInUseCount = 0 ; 260 261 #ifdef ASSERT 262 _visited_for_critical_count = false; 263 #endif 264 265 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 266 _suspend_flags = 0; 267 268 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 269 _hashStateX = os::random() ; 270 _hashStateY = 842502087 ; 271 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 272 _hashStateW = 273326509 ; 273 274 _OnTrap = 0 ; 275 _schedctl = NULL ; 276 _Stalled = 0 ; 277 _TypeTag = 0x2BAD ; 278 279 // Many of the following fields are effectively final - immutable 280 // Note that nascent threads can't use the Native Monitor-Mutex 281 // construct until the _MutexEvent is initialized ... 282 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 283 // we might instead use a stack of ParkEvents that we could provision on-demand. 284 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 285 // and ::Release() 286 _ParkEvent = ParkEvent::Allocate (this) ; 287 _SleepEvent = ParkEvent::Allocate (this) ; 288 _MutexEvent = ParkEvent::Allocate (this) ; 289 _MuxEvent = ParkEvent::Allocate (this) ; 290 291 #ifdef CHECK_UNHANDLED_OOPS 292 if (CheckUnhandledOops) { 293 _unhandled_oops = new UnhandledOops(this); 294 } 295 #endif // CHECK_UNHANDLED_OOPS 296 #ifdef ASSERT 297 if (UseBiasedLocking) { 298 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 299 assert(this == _real_malloc_address || 300 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 301 "bug in forced alignment of thread objects"); 302 } 303 #endif /* ASSERT */ 304 } 305 306 void Thread::initialize_thread_local_storage() { 307 // Note: Make sure this method only calls 308 // non-blocking operations. Otherwise, it might not work 309 // with the thread-startup/safepoint interaction. 310 311 // During Java thread startup, safepoint code should allow this 312 // method to complete because it may need to allocate memory to 313 // store information for the new thread. 314 315 // initialize structure dependent on thread local storage 316 ThreadLocalStorage::set_thread(this); 317 } 318 319 void Thread::record_stack_base_and_size() { 320 set_stack_base(os::current_stack_base()); 321 set_stack_size(os::current_stack_size()); 322 if (is_Java_thread()) { 323 ((JavaThread*) this)->set_stack_overflow_limit(); 324 } 325 // CR 7190089: on Solaris, primordial thread's stack is adjusted 326 // in initialize_thread(). Without the adjustment, stack size is 327 // incorrect if stack is set to unlimited (ulimit -s unlimited). 328 // So far, only Solaris has real implementation of initialize_thread(). 329 // 330 // set up any platform-specific state. 331 os::initialize_thread(this); 332 333 #if INCLUDE_NMT 334 // record thread's native stack, stack grows downward 335 address stack_low_addr = stack_base() - stack_size(); 336 MemTracker::record_thread_stack(stack_low_addr, stack_size()); 337 #endif // INCLUDE_NMT 338 } 339 340 341 Thread::~Thread() { 342 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 343 ObjectSynchronizer::omFlush (this) ; 344 345 EVENT_THREAD_DESTRUCT(this); 346 347 // stack_base can be NULL if the thread is never started or exited before 348 // record_stack_base_and_size called. Although, we would like to ensure 349 // that all started threads do call record_stack_base_and_size(), there is 350 // not proper way to enforce that. 351 #if INCLUDE_NMT 352 if (_stack_base != NULL) { 353 address low_stack_addr = stack_base() - stack_size(); 354 MemTracker::release_thread_stack(low_stack_addr, stack_size()); 355 #ifdef ASSERT 356 set_stack_base(NULL); 357 #endif 358 } 359 #endif // INCLUDE_NMT 360 361 // deallocate data structures 362 delete resource_area(); 363 // since the handle marks are using the handle area, we have to deallocated the root 364 // handle mark before deallocating the thread's handle area, 365 assert(last_handle_mark() != NULL, "check we have an element"); 366 delete last_handle_mark(); 367 assert(last_handle_mark() == NULL, "check we have reached the end"); 368 369 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 370 // We NULL out the fields for good hygiene. 371 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 372 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 373 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 374 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 375 376 delete handle_area(); 377 delete metadata_handles(); 378 379 // osthread() can be NULL, if creation of thread failed. 380 if (osthread() != NULL) os::free_thread(osthread()); 381 382 delete _SR_lock; 383 384 // clear thread local storage if the Thread is deleting itself 385 if (this == Thread::current()) { 386 ThreadLocalStorage::set_thread(NULL); 387 } else { 388 // In the case where we're not the current thread, invalidate all the 389 // caches in case some code tries to get the current thread or the 390 // thread that was destroyed, and gets stale information. 391 ThreadLocalStorage::invalidate_all(); 392 } 393 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 394 } 395 396 // NOTE: dummy function for assertion purpose. 397 void Thread::run() { 398 ShouldNotReachHere(); 399 } 400 401 #ifdef ASSERT 402 // Private method to check for dangling thread pointer 403 void check_for_dangling_thread_pointer(Thread *thread) { 404 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 405 "possibility of dangling Thread pointer"); 406 } 407 #endif 408 409 410 #ifndef PRODUCT 411 // Tracing method for basic thread operations 412 void Thread::trace(const char* msg, const Thread* const thread) { 413 if (!TraceThreadEvents) return; 414 ResourceMark rm; 415 ThreadCritical tc; 416 const char *name = "non-Java thread"; 417 int prio = -1; 418 if (thread->is_Java_thread() 419 && !thread->is_Compiler_thread()) { 420 // The Threads_lock must be held to get information about 421 // this thread but may not be in some situations when 422 // tracing thread events. 423 bool release_Threads_lock = false; 424 if (!Threads_lock->owned_by_self()) { 425 Threads_lock->lock(); 426 release_Threads_lock = true; 427 } 428 JavaThread* jt = (JavaThread *)thread; 429 name = (char *)jt->get_thread_name(); 430 oop thread_oop = jt->threadObj(); 431 if (thread_oop != NULL) { 432 prio = java_lang_Thread::priority(thread_oop); 433 } 434 if (release_Threads_lock) { 435 Threads_lock->unlock(); 436 } 437 } 438 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 439 } 440 #endif 441 442 443 ThreadPriority Thread::get_priority(const Thread* const thread) { 444 trace("get priority", thread); 445 ThreadPriority priority; 446 // Can return an error! 447 (void)os::get_priority(thread, priority); 448 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 449 return priority; 450 } 451 452 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 453 trace("set priority", thread); 454 debug_only(check_for_dangling_thread_pointer(thread);) 455 // Can return an error! 456 (void)os::set_priority(thread, priority); 457 } 458 459 460 void Thread::start(Thread* thread) { 461 trace("start", thread); 462 // Start is different from resume in that its safety is guaranteed by context or 463 // being called from a Java method synchronized on the Thread object. 464 if (!DisableStartThread) { 465 if (thread->is_Java_thread()) { 466 // Initialize the thread state to RUNNABLE before starting this thread. 467 // Can not set it after the thread started because we do not know the 468 // exact thread state at that time. It could be in MONITOR_WAIT or 469 // in SLEEPING or some other state. 470 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 471 java_lang_Thread::RUNNABLE); 472 } 473 os::start_thread(thread); 474 } 475 } 476 477 // Enqueue a VM_Operation to do the job for us - sometime later 478 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 479 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 480 VMThread::execute(vm_stop); 481 } 482 483 484 // 485 // Check if an external suspend request has completed (or has been 486 // cancelled). Returns true if the thread is externally suspended and 487 // false otherwise. 488 // 489 // The bits parameter returns information about the code path through 490 // the routine. Useful for debugging: 491 // 492 // set in is_ext_suspend_completed(): 493 // 0x00000001 - routine was entered 494 // 0x00000010 - routine return false at end 495 // 0x00000100 - thread exited (return false) 496 // 0x00000200 - suspend request cancelled (return false) 497 // 0x00000400 - thread suspended (return true) 498 // 0x00001000 - thread is in a suspend equivalent state (return true) 499 // 0x00002000 - thread is native and walkable (return true) 500 // 0x00004000 - thread is native_trans and walkable (needed retry) 501 // 502 // set in wait_for_ext_suspend_completion(): 503 // 0x00010000 - routine was entered 504 // 0x00020000 - suspend request cancelled before loop (return false) 505 // 0x00040000 - thread suspended before loop (return true) 506 // 0x00080000 - suspend request cancelled in loop (return false) 507 // 0x00100000 - thread suspended in loop (return true) 508 // 0x00200000 - suspend not completed during retry loop (return false) 509 // 510 511 // Helper class for tracing suspend wait debug bits. 512 // 513 // 0x00000100 indicates that the target thread exited before it could 514 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 515 // 0x00080000 each indicate a cancelled suspend request so they don't 516 // count as wait failures either. 517 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 518 519 class TraceSuspendDebugBits : public StackObj { 520 private: 521 JavaThread * jt; 522 bool is_wait; 523 bool called_by_wait; // meaningful when !is_wait 524 uint32_t * bits; 525 526 public: 527 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 528 uint32_t *_bits) { 529 jt = _jt; 530 is_wait = _is_wait; 531 called_by_wait = _called_by_wait; 532 bits = _bits; 533 } 534 535 ~TraceSuspendDebugBits() { 536 if (!is_wait) { 537 #if 1 538 // By default, don't trace bits for is_ext_suspend_completed() calls. 539 // That trace is very chatty. 540 return; 541 #else 542 if (!called_by_wait) { 543 // If tracing for is_ext_suspend_completed() is enabled, then only 544 // trace calls to it from wait_for_ext_suspend_completion() 545 return; 546 } 547 #endif 548 } 549 550 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 551 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 552 MutexLocker ml(Threads_lock); // needed for get_thread_name() 553 ResourceMark rm; 554 555 tty->print_cr( 556 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 557 jt->get_thread_name(), *bits); 558 559 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 560 } 561 } 562 } 563 }; 564 #undef DEBUG_FALSE_BITS 565 566 567 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 568 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 569 570 bool did_trans_retry = false; // only do thread_in_native_trans retry once 571 bool do_trans_retry; // flag to force the retry 572 573 *bits |= 0x00000001; 574 575 do { 576 do_trans_retry = false; 577 578 if (is_exiting()) { 579 // Thread is in the process of exiting. This is always checked 580 // first to reduce the risk of dereferencing a freed JavaThread. 581 *bits |= 0x00000100; 582 return false; 583 } 584 585 if (!is_external_suspend()) { 586 // Suspend request is cancelled. This is always checked before 587 // is_ext_suspended() to reduce the risk of a rogue resume 588 // confusing the thread that made the suspend request. 589 *bits |= 0x00000200; 590 return false; 591 } 592 593 if (is_ext_suspended()) { 594 // thread is suspended 595 *bits |= 0x00000400; 596 return true; 597 } 598 599 // Now that we no longer do hard suspends of threads running 600 // native code, the target thread can be changing thread state 601 // while we are in this routine: 602 // 603 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 604 // 605 // We save a copy of the thread state as observed at this moment 606 // and make our decision about suspend completeness based on the 607 // copy. This closes the race where the thread state is seen as 608 // _thread_in_native_trans in the if-thread_blocked check, but is 609 // seen as _thread_blocked in if-thread_in_native_trans check. 610 JavaThreadState save_state = thread_state(); 611 612 if (save_state == _thread_blocked && is_suspend_equivalent()) { 613 // If the thread's state is _thread_blocked and this blocking 614 // condition is known to be equivalent to a suspend, then we can 615 // consider the thread to be externally suspended. This means that 616 // the code that sets _thread_blocked has been modified to do 617 // self-suspension if the blocking condition releases. We also 618 // used to check for CONDVAR_WAIT here, but that is now covered by 619 // the _thread_blocked with self-suspension check. 620 // 621 // Return true since we wouldn't be here unless there was still an 622 // external suspend request. 623 *bits |= 0x00001000; 624 return true; 625 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 626 // Threads running native code will self-suspend on native==>VM/Java 627 // transitions. If its stack is walkable (should always be the case 628 // unless this function is called before the actual java_suspend() 629 // call), then the wait is done. 630 *bits |= 0x00002000; 631 return true; 632 } else if (!called_by_wait && !did_trans_retry && 633 save_state == _thread_in_native_trans && 634 frame_anchor()->walkable()) { 635 // The thread is transitioning from thread_in_native to another 636 // thread state. check_safepoint_and_suspend_for_native_trans() 637 // will force the thread to self-suspend. If it hasn't gotten 638 // there yet we may have caught the thread in-between the native 639 // code check above and the self-suspend. Lucky us. If we were 640 // called by wait_for_ext_suspend_completion(), then it 641 // will be doing the retries so we don't have to. 642 // 643 // Since we use the saved thread state in the if-statement above, 644 // there is a chance that the thread has already transitioned to 645 // _thread_blocked by the time we get here. In that case, we will 646 // make a single unnecessary pass through the logic below. This 647 // doesn't hurt anything since we still do the trans retry. 648 649 *bits |= 0x00004000; 650 651 // Once the thread leaves thread_in_native_trans for another 652 // thread state, we break out of this retry loop. We shouldn't 653 // need this flag to prevent us from getting back here, but 654 // sometimes paranoia is good. 655 did_trans_retry = true; 656 657 // We wait for the thread to transition to a more usable state. 658 for (int i = 1; i <= SuspendRetryCount; i++) { 659 // We used to do an "os::yield_all(i)" call here with the intention 660 // that yielding would increase on each retry. However, the parameter 661 // is ignored on Linux which means the yield didn't scale up. Waiting 662 // on the SR_lock below provides a much more predictable scale up for 663 // the delay. It also provides a simple/direct point to check for any 664 // safepoint requests from the VMThread 665 666 // temporarily drops SR_lock while doing wait with safepoint check 667 // (if we're a JavaThread - the WatcherThread can also call this) 668 // and increase delay with each retry 669 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 670 671 // check the actual thread state instead of what we saved above 672 if (thread_state() != _thread_in_native_trans) { 673 // the thread has transitioned to another thread state so 674 // try all the checks (except this one) one more time. 675 do_trans_retry = true; 676 break; 677 } 678 } // end retry loop 679 680 681 } 682 } while (do_trans_retry); 683 684 *bits |= 0x00000010; 685 return false; 686 } 687 688 // 689 // Wait for an external suspend request to complete (or be cancelled). 690 // Returns true if the thread is externally suspended and false otherwise. 691 // 692 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 693 uint32_t *bits) { 694 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 695 false /* !called_by_wait */, bits); 696 697 // local flag copies to minimize SR_lock hold time 698 bool is_suspended; 699 bool pending; 700 uint32_t reset_bits; 701 702 // set a marker so is_ext_suspend_completed() knows we are the caller 703 *bits |= 0x00010000; 704 705 // We use reset_bits to reinitialize the bits value at the top of 706 // each retry loop. This allows the caller to make use of any 707 // unused bits for their own marking purposes. 708 reset_bits = *bits; 709 710 { 711 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 712 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 713 delay, bits); 714 pending = is_external_suspend(); 715 } 716 // must release SR_lock to allow suspension to complete 717 718 if (!pending) { 719 // A cancelled suspend request is the only false return from 720 // is_ext_suspend_completed() that keeps us from entering the 721 // retry loop. 722 *bits |= 0x00020000; 723 return false; 724 } 725 726 if (is_suspended) { 727 *bits |= 0x00040000; 728 return true; 729 } 730 731 for (int i = 1; i <= retries; i++) { 732 *bits = reset_bits; // reinit to only track last retry 733 734 // We used to do an "os::yield_all(i)" call here with the intention 735 // that yielding would increase on each retry. However, the parameter 736 // is ignored on Linux which means the yield didn't scale up. Waiting 737 // on the SR_lock below provides a much more predictable scale up for 738 // the delay. It also provides a simple/direct point to check for any 739 // safepoint requests from the VMThread 740 741 { 742 MutexLocker ml(SR_lock()); 743 // wait with safepoint check (if we're a JavaThread - the WatcherThread 744 // can also call this) and increase delay with each retry 745 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 746 747 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 748 delay, bits); 749 750 // It is possible for the external suspend request to be cancelled 751 // (by a resume) before the actual suspend operation is completed. 752 // Refresh our local copy to see if we still need to wait. 753 pending = is_external_suspend(); 754 } 755 756 if (!pending) { 757 // A cancelled suspend request is the only false return from 758 // is_ext_suspend_completed() that keeps us from staying in the 759 // retry loop. 760 *bits |= 0x00080000; 761 return false; 762 } 763 764 if (is_suspended) { 765 *bits |= 0x00100000; 766 return true; 767 } 768 } // end retry loop 769 770 // thread did not suspend after all our retries 771 *bits |= 0x00200000; 772 return false; 773 } 774 775 #ifndef PRODUCT 776 void JavaThread::record_jump(address target, address instr, const char* file, int line) { 777 778 // This should not need to be atomic as the only way for simultaneous 779 // updates is via interrupts. Even then this should be rare or non-existant 780 // and we don't care that much anyway. 781 782 int index = _jmp_ring_index; 783 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 784 _jmp_ring[index]._target = (intptr_t) target; 785 _jmp_ring[index]._instruction = (intptr_t) instr; 786 _jmp_ring[index]._file = file; 787 _jmp_ring[index]._line = line; 788 } 789 #endif /* PRODUCT */ 790 791 // Called by flat profiler 792 // Callers have already called wait_for_ext_suspend_completion 793 // The assertion for that is currently too complex to put here: 794 bool JavaThread::profile_last_Java_frame(frame* _fr) { 795 bool gotframe = false; 796 // self suspension saves needed state. 797 if (has_last_Java_frame() && _anchor.walkable()) { 798 *_fr = pd_last_frame(); 799 gotframe = true; 800 } 801 return gotframe; 802 } 803 804 void Thread::interrupt(Thread* thread) { 805 trace("interrupt", thread); 806 debug_only(check_for_dangling_thread_pointer(thread);) 807 os::interrupt(thread); 808 } 809 810 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 811 trace("is_interrupted", thread); 812 debug_only(check_for_dangling_thread_pointer(thread);) 813 // Note: If clear_interrupted==false, this simply fetches and 814 // returns the value of the field osthread()->interrupted(). 815 return os::is_interrupted(thread, clear_interrupted); 816 } 817 818 819 // GC Support 820 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 821 jint thread_parity = _oops_do_parity; 822 if (thread_parity != strong_roots_parity) { 823 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 824 if (res == thread_parity) { 825 return true; 826 } else { 827 guarantee(res == strong_roots_parity, "Or else what?"); 828 assert(SharedHeap::heap()->workers()->active_workers() > 0, 829 "Should only fail when parallel."); 830 return false; 831 } 832 } 833 assert(SharedHeap::heap()->workers()->active_workers() > 0, 834 "Should only fail when parallel."); 835 return false; 836 } 837 838 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 839 active_handles()->oops_do(f); 840 // Do oop for ThreadShadow 841 f->do_oop((oop*)&_pending_exception); 842 handle_area()->oops_do(f); 843 } 844 845 void Thread::nmethods_do(CodeBlobClosure* cf) { 846 // no nmethods in a generic thread... 847 } 848 849 void Thread::metadata_do(void f(Metadata*)) { 850 if (metadata_handles() != NULL) { 851 for (int i = 0; i< metadata_handles()->length(); i++) { 852 f(metadata_handles()->at(i)); 853 } 854 } 855 } 856 857 void Thread::print_on(outputStream* st) const { 858 // get_priority assumes osthread initialized 859 if (osthread() != NULL) { 860 int os_prio; 861 if (os::get_native_priority(this, &os_prio) == OS_OK) { 862 st->print("os_prio=%d ", os_prio); 863 } 864 st->print("tid=" INTPTR_FORMAT " ", this); 865 ext().print_on(st); 866 osthread()->print_on(st); 867 } 868 debug_only(if (WizardMode) print_owned_locks_on(st);) 869 } 870 871 // Thread::print_on_error() is called by fatal error handler. Don't use 872 // any lock or allocate memory. 873 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 874 if (is_VM_thread()) st->print("VMThread"); 875 else if (is_Compiler_thread()) st->print("CompilerThread"); 876 else if (is_Java_thread()) st->print("JavaThread"); 877 else if (is_GC_task_thread()) st->print("GCTaskThread"); 878 else if (is_Watcher_thread()) st->print("WatcherThread"); 879 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 880 else st->print("Thread"); 881 882 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 883 _stack_base - _stack_size, _stack_base); 884 885 if (osthread()) { 886 st->print(" [id=%d]", osthread()->thread_id()); 887 } 888 } 889 890 #ifdef ASSERT 891 void Thread::print_owned_locks_on(outputStream* st) const { 892 Monitor *cur = _owned_locks; 893 if (cur == NULL) { 894 st->print(" (no locks) "); 895 } else { 896 st->print_cr(" Locks owned:"); 897 while(cur) { 898 cur->print_on(st); 899 cur = cur->next(); 900 } 901 } 902 } 903 904 static int ref_use_count = 0; 905 906 bool Thread::owns_locks_but_compiled_lock() const { 907 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 908 if (cur != Compile_lock) return true; 909 } 910 return false; 911 } 912 913 914 #endif 915 916 #ifndef PRODUCT 917 918 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 919 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 920 // no threads which allow_vm_block's are held 921 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 922 // Check if current thread is allowed to block at a safepoint 923 if (!(_allow_safepoint_count == 0)) 924 fatal("Possible safepoint reached by thread that does not allow it"); 925 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 926 fatal("LEAF method calling lock?"); 927 } 928 929 #ifdef ASSERT 930 if (potential_vm_operation && is_Java_thread() 931 && !Universe::is_bootstrapping()) { 932 // Make sure we do not hold any locks that the VM thread also uses. 933 // This could potentially lead to deadlocks 934 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 935 // Threads_lock is special, since the safepoint synchronization will not start before this is 936 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 937 // since it is used to transfer control between JavaThreads and the VMThread 938 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first! 939 if ( (cur->allow_vm_block() && 940 cur != Threads_lock && 941 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation 942 cur != VMOperationRequest_lock && 943 cur != VMOperationQueue_lock) || 944 cur->rank() == Mutex::special) { 945 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name())); 946 } 947 } 948 } 949 950 if (GCALotAtAllSafepoints) { 951 // We could enter a safepoint here and thus have a gc 952 InterfaceSupport::check_gc_alot(); 953 } 954 #endif 955 } 956 #endif 957 958 bool Thread::is_in_stack(address adr) const { 959 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 960 address end = os::current_stack_pointer(); 961 // Allow non Java threads to call this without stack_base 962 if (_stack_base == NULL) return true; 963 if (stack_base() >= adr && adr >= end) return true; 964 965 return false; 966 } 967 968 969 bool Thread::is_in_usable_stack(address adr) const { 970 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 971 size_t usable_stack_size = _stack_size - stack_guard_size; 972 973 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 974 } 975 976 977 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 978 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 979 // used for compilation in the future. If that change is made, the need for these methods 980 // should be revisited, and they should be removed if possible. 981 982 bool Thread::is_lock_owned(address adr) const { 983 return on_local_stack(adr); 984 } 985 986 bool Thread::set_as_starting_thread() { 987 // NOTE: this must be called inside the main thread. 988 return os::create_main_thread((JavaThread*)this); 989 } 990 991 static void initialize_class(Symbol* class_name, TRAPS) { 992 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 993 InstanceKlass::cast(klass)->initialize(CHECK); 994 } 995 996 997 // Creates the initial ThreadGroup 998 static Handle create_initial_thread_group(TRAPS) { 999 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 1000 instanceKlassHandle klass (THREAD, k); 1001 1002 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 1003 { 1004 JavaValue result(T_VOID); 1005 JavaCalls::call_special(&result, 1006 system_instance, 1007 klass, 1008 vmSymbols::object_initializer_name(), 1009 vmSymbols::void_method_signature(), 1010 CHECK_NH); 1011 } 1012 Universe::set_system_thread_group(system_instance()); 1013 1014 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 1015 { 1016 JavaValue result(T_VOID); 1017 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 1018 JavaCalls::call_special(&result, 1019 main_instance, 1020 klass, 1021 vmSymbols::object_initializer_name(), 1022 vmSymbols::threadgroup_string_void_signature(), 1023 system_instance, 1024 string, 1025 CHECK_NH); 1026 } 1027 return main_instance; 1028 } 1029 1030 // Creates the initial Thread 1031 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1032 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1033 instanceKlassHandle klass (THREAD, k); 1034 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1035 1036 java_lang_Thread::set_thread(thread_oop(), thread); 1037 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1038 thread->set_threadObj(thread_oop()); 1039 1040 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1041 1042 JavaValue result(T_VOID); 1043 JavaCalls::call_special(&result, thread_oop, 1044 klass, 1045 vmSymbols::object_initializer_name(), 1046 vmSymbols::threadgroup_string_void_signature(), 1047 thread_group, 1048 string, 1049 CHECK_NULL); 1050 return thread_oop(); 1051 } 1052 1053 static void call_initializeSystemClass(TRAPS) { 1054 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1055 instanceKlassHandle klass (THREAD, k); 1056 1057 JavaValue result(T_VOID); 1058 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1059 vmSymbols::void_method_signature(), CHECK); 1060 } 1061 1062 char java_runtime_name[128] = ""; 1063 char java_runtime_version[128] = ""; 1064 1065 // extract the JRE name from sun.misc.Version.java_runtime_name 1066 static const char* get_java_runtime_name(TRAPS) { 1067 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1068 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1069 fieldDescriptor fd; 1070 bool found = k != NULL && 1071 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1072 vmSymbols::string_signature(), &fd); 1073 if (found) { 1074 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1075 if (name_oop == NULL) 1076 return NULL; 1077 const char* name = java_lang_String::as_utf8_string(name_oop, 1078 java_runtime_name, 1079 sizeof(java_runtime_name)); 1080 return name; 1081 } else { 1082 return NULL; 1083 } 1084 } 1085 1086 // extract the JRE version from sun.misc.Version.java_runtime_version 1087 static const char* get_java_runtime_version(TRAPS) { 1088 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1089 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1090 fieldDescriptor fd; 1091 bool found = k != NULL && 1092 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1093 vmSymbols::string_signature(), &fd); 1094 if (found) { 1095 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1096 if (name_oop == NULL) 1097 return NULL; 1098 const char* name = java_lang_String::as_utf8_string(name_oop, 1099 java_runtime_version, 1100 sizeof(java_runtime_version)); 1101 return name; 1102 } else { 1103 return NULL; 1104 } 1105 } 1106 1107 // General purpose hook into Java code, run once when the VM is initialized. 1108 // The Java library method itself may be changed independently from the VM. 1109 static void call_postVMInitHook(TRAPS) { 1110 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1111 instanceKlassHandle klass (THREAD, k); 1112 if (klass.not_null()) { 1113 JavaValue result(T_VOID); 1114 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1115 vmSymbols::void_method_signature(), 1116 CHECK); 1117 } 1118 } 1119 1120 static void reset_vm_info_property(TRAPS) { 1121 // the vm info string 1122 ResourceMark rm(THREAD); 1123 const char *vm_info = VM_Version::vm_info_string(); 1124 1125 // java.lang.System class 1126 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1127 instanceKlassHandle klass (THREAD, k); 1128 1129 // setProperty arguments 1130 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1131 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1132 1133 // return value 1134 JavaValue r(T_OBJECT); 1135 1136 // public static String setProperty(String key, String value); 1137 JavaCalls::call_static(&r, 1138 klass, 1139 vmSymbols::setProperty_name(), 1140 vmSymbols::string_string_string_signature(), 1141 key_str, 1142 value_str, 1143 CHECK); 1144 } 1145 1146 1147 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1148 assert(thread_group.not_null(), "thread group should be specified"); 1149 assert(threadObj() == NULL, "should only create Java thread object once"); 1150 1151 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1152 instanceKlassHandle klass (THREAD, k); 1153 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1154 1155 java_lang_Thread::set_thread(thread_oop(), this); 1156 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1157 set_threadObj(thread_oop()); 1158 1159 JavaValue result(T_VOID); 1160 if (thread_name != NULL) { 1161 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1162 // Thread gets assigned specified name and null target 1163 JavaCalls::call_special(&result, 1164 thread_oop, 1165 klass, 1166 vmSymbols::object_initializer_name(), 1167 vmSymbols::threadgroup_string_void_signature(), 1168 thread_group, // Argument 1 1169 name, // Argument 2 1170 THREAD); 1171 } else { 1172 // Thread gets assigned name "Thread-nnn" and null target 1173 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1174 JavaCalls::call_special(&result, 1175 thread_oop, 1176 klass, 1177 vmSymbols::object_initializer_name(), 1178 vmSymbols::threadgroup_runnable_void_signature(), 1179 thread_group, // Argument 1 1180 Handle(), // Argument 2 1181 THREAD); 1182 } 1183 1184 1185 if (daemon) { 1186 java_lang_Thread::set_daemon(thread_oop()); 1187 } 1188 1189 if (HAS_PENDING_EXCEPTION) { 1190 return; 1191 } 1192 1193 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1194 Handle threadObj(this, this->threadObj()); 1195 1196 JavaCalls::call_special(&result, 1197 thread_group, 1198 group, 1199 vmSymbols::add_method_name(), 1200 vmSymbols::thread_void_signature(), 1201 threadObj, // Arg 1 1202 THREAD); 1203 1204 1205 } 1206 1207 // NamedThread -- non-JavaThread subclasses with multiple 1208 // uniquely named instances should derive from this. 1209 NamedThread::NamedThread() : Thread() { 1210 _name = NULL; 1211 _processed_thread = NULL; 1212 } 1213 1214 NamedThread::~NamedThread() { 1215 if (_name != NULL) { 1216 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1217 _name = NULL; 1218 } 1219 } 1220 1221 void NamedThread::set_name(const char* format, ...) { 1222 guarantee(_name == NULL, "Only get to set name once."); 1223 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1224 guarantee(_name != NULL, "alloc failure"); 1225 va_list ap; 1226 va_start(ap, format); 1227 jio_vsnprintf(_name, max_name_len, format, ap); 1228 va_end(ap); 1229 } 1230 1231 // ======= WatcherThread ======== 1232 1233 // The watcher thread exists to simulate timer interrupts. It should 1234 // be replaced by an abstraction over whatever native support for 1235 // timer interrupts exists on the platform. 1236 1237 WatcherThread* WatcherThread::_watcher_thread = NULL; 1238 bool WatcherThread::_startable = false; 1239 volatile bool WatcherThread::_should_terminate = false; 1240 1241 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1242 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1243 if (os::create_thread(this, os::watcher_thread)) { 1244 _watcher_thread = this; 1245 1246 // Set the watcher thread to the highest OS priority which should not be 1247 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1248 // is created. The only normal thread using this priority is the reference 1249 // handler thread, which runs for very short intervals only. 1250 // If the VMThread's priority is not lower than the WatcherThread profiling 1251 // will be inaccurate. 1252 os::set_priority(this, MaxPriority); 1253 if (!DisableStartThread) { 1254 os::start_thread(this); 1255 } 1256 } 1257 } 1258 1259 int WatcherThread::sleep() const { 1260 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1261 1262 // remaining will be zero if there are no tasks, 1263 // causing the WatcherThread to sleep until a task is 1264 // enrolled 1265 int remaining = PeriodicTask::time_to_wait(); 1266 int time_slept = 0; 1267 1268 // we expect this to timeout - we only ever get unparked when 1269 // we should terminate or when a new task has been enrolled 1270 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1271 1272 jlong time_before_loop = os::javaTimeNanos(); 1273 1274 for (;;) { 1275 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1276 jlong now = os::javaTimeNanos(); 1277 1278 if (remaining == 0) { 1279 // if we didn't have any tasks we could have waited for a long time 1280 // consider the time_slept zero and reset time_before_loop 1281 time_slept = 0; 1282 time_before_loop = now; 1283 } else { 1284 // need to recalulate since we might have new tasks in _tasks 1285 time_slept = (int) ((now - time_before_loop) / 1000000); 1286 } 1287 1288 // Change to task list or spurious wakeup of some kind 1289 if (timedout || _should_terminate) { 1290 break; 1291 } 1292 1293 remaining = PeriodicTask::time_to_wait(); 1294 if (remaining == 0) { 1295 // Last task was just disenrolled so loop around and wait until 1296 // another task gets enrolled 1297 continue; 1298 } 1299 1300 remaining -= time_slept; 1301 if (remaining <= 0) 1302 break; 1303 } 1304 1305 return time_slept; 1306 } 1307 1308 void WatcherThread::run() { 1309 assert(this == watcher_thread(), "just checking"); 1310 1311 this->record_stack_base_and_size(); 1312 this->initialize_thread_local_storage(); 1313 this->set_active_handles(JNIHandleBlock::allocate_block()); 1314 while(!_should_terminate) { 1315 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1316 assert(watcher_thread() == this, "thread consistency check"); 1317 1318 // Calculate how long it'll be until the next PeriodicTask work 1319 // should be done, and sleep that amount of time. 1320 int time_waited = sleep(); 1321 1322 if (is_error_reported()) { 1323 // A fatal error has happened, the error handler(VMError::report_and_die) 1324 // should abort JVM after creating an error log file. However in some 1325 // rare cases, the error handler itself might deadlock. Here we try to 1326 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1327 // 1328 // This code is in WatcherThread because WatcherThread wakes up 1329 // periodically so the fatal error handler doesn't need to do anything; 1330 // also because the WatcherThread is less likely to crash than other 1331 // threads. 1332 1333 for (;;) { 1334 if (!ShowMessageBoxOnError 1335 && (OnError == NULL || OnError[0] == '\0') 1336 && Arguments::abort_hook() == NULL) { 1337 os::sleep(this, 2 * 60 * 1000, false); 1338 fdStream err(defaultStream::output_fd()); 1339 err.print_raw_cr("# [ timer expired, abort... ]"); 1340 // skip atexit/vm_exit/vm_abort hooks 1341 os::die(); 1342 } 1343 1344 // Wake up 5 seconds later, the fatal handler may reset OnError or 1345 // ShowMessageBoxOnError when it is ready to abort. 1346 os::sleep(this, 5 * 1000, false); 1347 } 1348 } 1349 1350 PeriodicTask::real_time_tick(time_waited); 1351 } 1352 1353 // Signal that it is terminated 1354 { 1355 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1356 _watcher_thread = NULL; 1357 Terminator_lock->notify(); 1358 } 1359 1360 // Thread destructor usually does this.. 1361 ThreadLocalStorage::set_thread(NULL); 1362 } 1363 1364 void WatcherThread::start() { 1365 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1366 1367 if (watcher_thread() == NULL && _startable) { 1368 _should_terminate = false; 1369 // Create the single instance of WatcherThread 1370 new WatcherThread(); 1371 } 1372 } 1373 1374 void WatcherThread::make_startable() { 1375 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1376 _startable = true; 1377 } 1378 1379 void WatcherThread::stop() { 1380 { 1381 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1382 _should_terminate = true; 1383 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1384 1385 WatcherThread* watcher = watcher_thread(); 1386 if (watcher != NULL) 1387 watcher->unpark(); 1388 } 1389 1390 // it is ok to take late safepoints here, if needed 1391 MutexLocker mu(Terminator_lock); 1392 1393 while(watcher_thread() != NULL) { 1394 // This wait should make safepoint checks, wait without a timeout, 1395 // and wait as a suspend-equivalent condition. 1396 // 1397 // Note: If the FlatProfiler is running, then this thread is waiting 1398 // for the WatcherThread to terminate and the WatcherThread, via the 1399 // FlatProfiler task, is waiting for the external suspend request on 1400 // this thread to complete. wait_for_ext_suspend_completion() will 1401 // eventually timeout, but that takes time. Making this wait a 1402 // suspend-equivalent condition solves that timeout problem. 1403 // 1404 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1405 Mutex::_as_suspend_equivalent_flag); 1406 } 1407 } 1408 1409 void WatcherThread::unpark() { 1410 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1411 PeriodicTask_lock->notify(); 1412 } 1413 1414 void WatcherThread::print_on(outputStream* st) const { 1415 st->print("\"%s\" ", name()); 1416 Thread::print_on(st); 1417 st->cr(); 1418 } 1419 1420 // ======= JavaThread ======== 1421 1422 // A JavaThread is a normal Java thread 1423 1424 void JavaThread::initialize() { 1425 // Initialize fields 1426 1427 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1428 set_claimed_par_id(UINT_MAX); 1429 1430 set_saved_exception_pc(NULL); 1431 set_threadObj(NULL); 1432 _anchor.clear(); 1433 set_entry_point(NULL); 1434 set_jni_functions(jni_functions()); 1435 set_callee_target(NULL); 1436 set_vm_result(NULL); 1437 set_vm_result_2(NULL); 1438 set_vframe_array_head(NULL); 1439 set_vframe_array_last(NULL); 1440 set_deferred_locals(NULL); 1441 set_deopt_mark(NULL); 1442 set_deopt_nmethod(NULL); 1443 clear_must_deopt_id(); 1444 set_monitor_chunks(NULL); 1445 set_next(NULL); 1446 set_thread_state(_thread_new); 1447 _terminated = _not_terminated; 1448 _privileged_stack_top = NULL; 1449 _array_for_gc = NULL; 1450 _suspend_equivalent = false; 1451 _in_deopt_handler = 0; 1452 _doing_unsafe_access = false; 1453 _stack_guard_state = stack_guard_unused; 1454 (void)const_cast<oop&>(_exception_oop = NULL); 1455 _exception_pc = 0; 1456 _exception_handler_pc = 0; 1457 _is_method_handle_return = 0; 1458 _jvmti_thread_state= NULL; 1459 _should_post_on_exceptions_flag = JNI_FALSE; 1460 _jvmti_get_loaded_classes_closure = NULL; 1461 _interp_only_mode = 0; 1462 _special_runtime_exit_condition = _no_async_condition; 1463 _pending_async_exception = NULL; 1464 _thread_stat = NULL; 1465 _thread_stat = new ThreadStatistics(); 1466 _blocked_on_compilation = false; 1467 _jni_active_critical = 0; 1468 _pending_jni_exception_check_fn = NULL; 1469 _do_not_unlock_if_synchronized = false; 1470 _cached_monitor_info = NULL; 1471 _parker = Parker::Allocate(this) ; 1472 1473 #ifndef PRODUCT 1474 _jmp_ring_index = 0; 1475 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1476 record_jump(NULL, NULL, NULL, 0); 1477 } 1478 #endif /* PRODUCT */ 1479 1480 set_thread_profiler(NULL); 1481 if (FlatProfiler::is_active()) { 1482 // This is where we would decide to either give each thread it's own profiler 1483 // or use one global one from FlatProfiler, 1484 // or up to some count of the number of profiled threads, etc. 1485 ThreadProfiler* pp = new ThreadProfiler(); 1486 pp->engage(); 1487 set_thread_profiler(pp); 1488 } 1489 1490 // Setup safepoint state info for this thread 1491 ThreadSafepointState::create(this); 1492 1493 debug_only(_java_call_counter = 0); 1494 1495 // JVMTI PopFrame support 1496 _popframe_condition = popframe_inactive; 1497 _popframe_preserved_args = NULL; 1498 _popframe_preserved_args_size = 0; 1499 _frames_to_pop_failed_realloc = 0; 1500 1501 pd_initialize(); 1502 } 1503 1504 #if INCLUDE_ALL_GCS 1505 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1506 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1507 #endif // INCLUDE_ALL_GCS 1508 1509 JavaThread::JavaThread(bool is_attaching_via_jni) : 1510 Thread() 1511 #if INCLUDE_ALL_GCS 1512 , _satb_mark_queue(&_satb_mark_queue_set), 1513 _dirty_card_queue(&_dirty_card_queue_set) 1514 #endif // INCLUDE_ALL_GCS 1515 { 1516 initialize(); 1517 if (is_attaching_via_jni) { 1518 _jni_attach_state = _attaching_via_jni; 1519 } else { 1520 _jni_attach_state = _not_attaching_via_jni; 1521 } 1522 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1523 } 1524 1525 bool JavaThread::reguard_stack(address cur_sp) { 1526 if (_stack_guard_state != stack_guard_yellow_disabled) { 1527 return true; // Stack already guarded or guard pages not needed. 1528 } 1529 1530 if (register_stack_overflow()) { 1531 // For those architectures which have separate register and 1532 // memory stacks, we must check the register stack to see if 1533 // it has overflowed. 1534 return false; 1535 } 1536 1537 // Java code never executes within the yellow zone: the latter is only 1538 // there to provoke an exception during stack banging. If java code 1539 // is executing there, either StackShadowPages should be larger, or 1540 // some exception code in c1, c2 or the interpreter isn't unwinding 1541 // when it should. 1542 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1543 1544 enable_stack_yellow_zone(); 1545 return true; 1546 } 1547 1548 bool JavaThread::reguard_stack(void) { 1549 return reguard_stack(os::current_stack_pointer()); 1550 } 1551 1552 1553 void JavaThread::block_if_vm_exited() { 1554 if (_terminated == _vm_exited) { 1555 // _vm_exited is set at safepoint, and Threads_lock is never released 1556 // we will block here forever 1557 Threads_lock->lock_without_safepoint_check(); 1558 ShouldNotReachHere(); 1559 } 1560 } 1561 1562 1563 // Remove this ifdef when C1 is ported to the compiler interface. 1564 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1565 1566 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1567 Thread() 1568 #if INCLUDE_ALL_GCS 1569 , _satb_mark_queue(&_satb_mark_queue_set), 1570 _dirty_card_queue(&_dirty_card_queue_set) 1571 #endif // INCLUDE_ALL_GCS 1572 { 1573 if (TraceThreadEvents) { 1574 tty->print_cr("creating thread %p", this); 1575 } 1576 initialize(); 1577 _jni_attach_state = _not_attaching_via_jni; 1578 set_entry_point(entry_point); 1579 // Create the native thread itself. 1580 // %note runtime_23 1581 os::ThreadType thr_type = os::java_thread; 1582 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1583 os::java_thread; 1584 os::create_thread(this, thr_type, stack_sz); 1585 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1586 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1587 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1588 // the exception consists of creating the exception object & initializing it, initialization 1589 // will leave the VM via a JavaCall and then all locks must be unlocked). 1590 // 1591 // The thread is still suspended when we reach here. Thread must be explicit started 1592 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1593 // by calling Threads:add. The reason why this is not done here, is because the thread 1594 // object must be fully initialized (take a look at JVM_Start) 1595 } 1596 1597 JavaThread::~JavaThread() { 1598 if (TraceThreadEvents) { 1599 tty->print_cr("terminate thread %p", this); 1600 } 1601 1602 // JSR166 -- return the parker to the free list 1603 Parker::Release(_parker); 1604 _parker = NULL ; 1605 1606 // Free any remaining previous UnrollBlock 1607 vframeArray* old_array = vframe_array_last(); 1608 1609 if (old_array != NULL) { 1610 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1611 old_array->set_unroll_block(NULL); 1612 delete old_info; 1613 delete old_array; 1614 } 1615 1616 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1617 if (deferred != NULL) { 1618 // This can only happen if thread is destroyed before deoptimization occurs. 1619 assert(deferred->length() != 0, "empty array!"); 1620 do { 1621 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1622 deferred->remove_at(0); 1623 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1624 delete dlv; 1625 } while (deferred->length() != 0); 1626 delete deferred; 1627 } 1628 1629 // All Java related clean up happens in exit 1630 ThreadSafepointState::destroy(this); 1631 if (_thread_profiler != NULL) delete _thread_profiler; 1632 if (_thread_stat != NULL) delete _thread_stat; 1633 } 1634 1635 1636 // The first routine called by a new Java thread 1637 void JavaThread::run() { 1638 // initialize thread-local alloc buffer related fields 1639 this->initialize_tlab(); 1640 1641 // used to test validitity of stack trace backs 1642 this->record_base_of_stack_pointer(); 1643 1644 // Record real stack base and size. 1645 this->record_stack_base_and_size(); 1646 1647 // Initialize thread local storage; set before calling MutexLocker 1648 this->initialize_thread_local_storage(); 1649 1650 this->create_stack_guard_pages(); 1651 1652 this->cache_global_variables(); 1653 1654 // Thread is now sufficient initialized to be handled by the safepoint code as being 1655 // in the VM. Change thread state from _thread_new to _thread_in_vm 1656 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1657 1658 assert(JavaThread::current() == this, "sanity check"); 1659 assert(!Thread::current()->owns_locks(), "sanity check"); 1660 1661 DTRACE_THREAD_PROBE(start, this); 1662 1663 // This operation might block. We call that after all safepoint checks for a new thread has 1664 // been completed. 1665 this->set_active_handles(JNIHandleBlock::allocate_block()); 1666 1667 if (JvmtiExport::should_post_thread_life()) { 1668 JvmtiExport::post_thread_start(this); 1669 } 1670 1671 EventThreadStart event; 1672 if (event.should_commit()) { 1673 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1674 event.commit(); 1675 } 1676 1677 // We call another function to do the rest so we are sure that the stack addresses used 1678 // from there will be lower than the stack base just computed 1679 thread_main_inner(); 1680 1681 // Note, thread is no longer valid at this point! 1682 } 1683 1684 1685 void JavaThread::thread_main_inner() { 1686 assert(JavaThread::current() == this, "sanity check"); 1687 assert(this->threadObj() != NULL, "just checking"); 1688 1689 // Execute thread entry point unless this thread has a pending exception 1690 // or has been stopped before starting. 1691 // Note: Due to JVM_StopThread we can have pending exceptions already! 1692 if (!this->has_pending_exception() && 1693 !java_lang_Thread::is_stillborn(this->threadObj())) { 1694 { 1695 ResourceMark rm(this); 1696 this->set_native_thread_name(this->get_thread_name()); 1697 } 1698 HandleMark hm(this); 1699 this->entry_point()(this, this); 1700 } 1701 1702 DTRACE_THREAD_PROBE(stop, this); 1703 1704 this->exit(false); 1705 delete this; 1706 } 1707 1708 1709 static void ensure_join(JavaThread* thread) { 1710 // We do not need to grap the Threads_lock, since we are operating on ourself. 1711 Handle threadObj(thread, thread->threadObj()); 1712 assert(threadObj.not_null(), "java thread object must exist"); 1713 ObjectLocker lock(threadObj, thread); 1714 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1715 thread->clear_pending_exception(); 1716 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1717 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1718 // Clear the native thread instance - this makes isAlive return false and allows the join() 1719 // to complete once we've done the notify_all below 1720 java_lang_Thread::set_thread(threadObj(), NULL); 1721 lock.notify_all(thread); 1722 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1723 thread->clear_pending_exception(); 1724 } 1725 1726 1727 // For any new cleanup additions, please check to see if they need to be applied to 1728 // cleanup_failed_attach_current_thread as well. 1729 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1730 assert(this == JavaThread::current(), "thread consistency check"); 1731 1732 HandleMark hm(this); 1733 Handle uncaught_exception(this, this->pending_exception()); 1734 this->clear_pending_exception(); 1735 Handle threadObj(this, this->threadObj()); 1736 assert(threadObj.not_null(), "Java thread object should be created"); 1737 1738 if (get_thread_profiler() != NULL) { 1739 get_thread_profiler()->disengage(); 1740 ResourceMark rm; 1741 get_thread_profiler()->print(get_thread_name()); 1742 } 1743 1744 1745 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1746 { 1747 EXCEPTION_MARK; 1748 1749 CLEAR_PENDING_EXCEPTION; 1750 } 1751 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1752 // has to be fixed by a runtime query method 1753 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1754 // JSR-166: change call from from ThreadGroup.uncaughtException to 1755 // java.lang.Thread.dispatchUncaughtException 1756 if (uncaught_exception.not_null()) { 1757 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1758 { 1759 EXCEPTION_MARK; 1760 // Check if the method Thread.dispatchUncaughtException() exists. If so 1761 // call it. Otherwise we have an older library without the JSR-166 changes, 1762 // so call ThreadGroup.uncaughtException() 1763 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1764 CallInfo callinfo; 1765 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1766 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1767 vmSymbols::dispatchUncaughtException_name(), 1768 vmSymbols::throwable_void_signature(), 1769 KlassHandle(), false, false, THREAD); 1770 CLEAR_PENDING_EXCEPTION; 1771 methodHandle method = callinfo.selected_method(); 1772 if (method.not_null()) { 1773 JavaValue result(T_VOID); 1774 JavaCalls::call_virtual(&result, 1775 threadObj, thread_klass, 1776 vmSymbols::dispatchUncaughtException_name(), 1777 vmSymbols::throwable_void_signature(), 1778 uncaught_exception, 1779 THREAD); 1780 } else { 1781 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1782 JavaValue result(T_VOID); 1783 JavaCalls::call_virtual(&result, 1784 group, thread_group, 1785 vmSymbols::uncaughtException_name(), 1786 vmSymbols::thread_throwable_void_signature(), 1787 threadObj, // Arg 1 1788 uncaught_exception, // Arg 2 1789 THREAD); 1790 } 1791 if (HAS_PENDING_EXCEPTION) { 1792 ResourceMark rm(this); 1793 jio_fprintf(defaultStream::error_stream(), 1794 "\nException: %s thrown from the UncaughtExceptionHandler" 1795 " in thread \"%s\"\n", 1796 pending_exception()->klass()->external_name(), 1797 get_thread_name()); 1798 CLEAR_PENDING_EXCEPTION; 1799 } 1800 } 1801 } 1802 1803 // Called before the java thread exit since we want to read info 1804 // from java_lang_Thread object 1805 EventThreadEnd event; 1806 if (event.should_commit()) { 1807 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1808 event.commit(); 1809 } 1810 1811 // Call after last event on thread 1812 EVENT_THREAD_EXIT(this); 1813 1814 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1815 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1816 // is deprecated anyhow. 1817 if (!is_Compiler_thread()) { 1818 int count = 3; 1819 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1820 EXCEPTION_MARK; 1821 JavaValue result(T_VOID); 1822 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1823 JavaCalls::call_virtual(&result, 1824 threadObj, thread_klass, 1825 vmSymbols::exit_method_name(), 1826 vmSymbols::void_method_signature(), 1827 THREAD); 1828 CLEAR_PENDING_EXCEPTION; 1829 } 1830 } 1831 // notify JVMTI 1832 if (JvmtiExport::should_post_thread_life()) { 1833 JvmtiExport::post_thread_end(this); 1834 } 1835 1836 // We have notified the agents that we are exiting, before we go on, 1837 // we must check for a pending external suspend request and honor it 1838 // in order to not surprise the thread that made the suspend request. 1839 while (true) { 1840 { 1841 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1842 if (!is_external_suspend()) { 1843 set_terminated(_thread_exiting); 1844 ThreadService::current_thread_exiting(this); 1845 break; 1846 } 1847 // Implied else: 1848 // Things get a little tricky here. We have a pending external 1849 // suspend request, but we are holding the SR_lock so we 1850 // can't just self-suspend. So we temporarily drop the lock 1851 // and then self-suspend. 1852 } 1853 1854 ThreadBlockInVM tbivm(this); 1855 java_suspend_self(); 1856 1857 // We're done with this suspend request, but we have to loop around 1858 // and check again. Eventually we will get SR_lock without a pending 1859 // external suspend request and will be able to mark ourselves as 1860 // exiting. 1861 } 1862 // no more external suspends are allowed at this point 1863 } else { 1864 // before_exit() has already posted JVMTI THREAD_END events 1865 } 1866 1867 // Notify waiters on thread object. This has to be done after exit() is called 1868 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1869 // group should have the destroyed bit set before waiters are notified). 1870 ensure_join(this); 1871 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1872 1873 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1874 // held by this thread must be released. A detach operation must only 1875 // get here if there are no Java frames on the stack. Therefore, any 1876 // owned monitors at this point MUST be JNI-acquired monitors which are 1877 // pre-inflated and in the monitor cache. 1878 // 1879 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1880 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1881 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1882 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1883 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1884 } 1885 1886 // These things needs to be done while we are still a Java Thread. Make sure that thread 1887 // is in a consistent state, in case GC happens 1888 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1889 1890 if (active_handles() != NULL) { 1891 JNIHandleBlock* block = active_handles(); 1892 set_active_handles(NULL); 1893 JNIHandleBlock::release_block(block); 1894 } 1895 1896 if (free_handle_block() != NULL) { 1897 JNIHandleBlock* block = free_handle_block(); 1898 set_free_handle_block(NULL); 1899 JNIHandleBlock::release_block(block); 1900 } 1901 1902 // These have to be removed while this is still a valid thread. 1903 remove_stack_guard_pages(); 1904 1905 if (UseTLAB) { 1906 tlab().make_parsable(true); // retire TLAB 1907 } 1908 1909 if (JvmtiEnv::environments_might_exist()) { 1910 JvmtiExport::cleanup_thread(this); 1911 } 1912 1913 // We must flush any deferred card marks before removing a thread from 1914 // the list of active threads. 1915 Universe::heap()->flush_deferred_store_barrier(this); 1916 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1917 1918 #if INCLUDE_ALL_GCS 1919 // We must flush the G1-related buffers before removing a thread 1920 // from the list of active threads. We must do this after any deferred 1921 // card marks have been flushed (above) so that any entries that are 1922 // added to the thread's dirty card queue as a result are not lost. 1923 if (UseG1GC) { 1924 flush_barrier_queues(); 1925 } 1926 #endif // INCLUDE_ALL_GCS 1927 1928 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1929 Threads::remove(this); 1930 } 1931 1932 #if INCLUDE_ALL_GCS 1933 // Flush G1-related queues. 1934 void JavaThread::flush_barrier_queues() { 1935 satb_mark_queue().flush(); 1936 dirty_card_queue().flush(); 1937 } 1938 1939 void JavaThread::initialize_queues() { 1940 assert(!SafepointSynchronize::is_at_safepoint(), 1941 "we should not be at a safepoint"); 1942 1943 ObjPtrQueue& satb_queue = satb_mark_queue(); 1944 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1945 // The SATB queue should have been constructed with its active 1946 // field set to false. 1947 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1948 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1949 // If we are creating the thread during a marking cycle, we should 1950 // set the active field of the SATB queue to true. 1951 if (satb_queue_set.is_active()) { 1952 satb_queue.set_active(true); 1953 } 1954 1955 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1956 // The dirty card queue should have been constructed with its 1957 // active field set to true. 1958 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1959 } 1960 #endif // INCLUDE_ALL_GCS 1961 1962 void JavaThread::cleanup_failed_attach_current_thread() { 1963 if (get_thread_profiler() != NULL) { 1964 get_thread_profiler()->disengage(); 1965 ResourceMark rm; 1966 get_thread_profiler()->print(get_thread_name()); 1967 } 1968 1969 if (active_handles() != NULL) { 1970 JNIHandleBlock* block = active_handles(); 1971 set_active_handles(NULL); 1972 JNIHandleBlock::release_block(block); 1973 } 1974 1975 if (free_handle_block() != NULL) { 1976 JNIHandleBlock* block = free_handle_block(); 1977 set_free_handle_block(NULL); 1978 JNIHandleBlock::release_block(block); 1979 } 1980 1981 // These have to be removed while this is still a valid thread. 1982 remove_stack_guard_pages(); 1983 1984 if (UseTLAB) { 1985 tlab().make_parsable(true); // retire TLAB, if any 1986 } 1987 1988 #if INCLUDE_ALL_GCS 1989 if (UseG1GC) { 1990 flush_barrier_queues(); 1991 } 1992 #endif // INCLUDE_ALL_GCS 1993 1994 Threads::remove(this); 1995 delete this; 1996 } 1997 1998 1999 2000 2001 JavaThread* JavaThread::active() { 2002 Thread* thread = ThreadLocalStorage::thread(); 2003 assert(thread != NULL, "just checking"); 2004 if (thread->is_Java_thread()) { 2005 return (JavaThread*) thread; 2006 } else { 2007 assert(thread->is_VM_thread(), "this must be a vm thread"); 2008 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2009 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2010 assert(ret->is_Java_thread(), "must be a Java thread"); 2011 return ret; 2012 } 2013 } 2014 2015 bool JavaThread::is_lock_owned(address adr) const { 2016 if (Thread::is_lock_owned(adr)) return true; 2017 2018 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2019 if (chunk->contains(adr)) return true; 2020 } 2021 2022 return false; 2023 } 2024 2025 2026 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2027 chunk->set_next(monitor_chunks()); 2028 set_monitor_chunks(chunk); 2029 } 2030 2031 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2032 guarantee(monitor_chunks() != NULL, "must be non empty"); 2033 if (monitor_chunks() == chunk) { 2034 set_monitor_chunks(chunk->next()); 2035 } else { 2036 MonitorChunk* prev = monitor_chunks(); 2037 while (prev->next() != chunk) prev = prev->next(); 2038 prev->set_next(chunk->next()); 2039 } 2040 } 2041 2042 // JVM support. 2043 2044 // Note: this function shouldn't block if it's called in 2045 // _thread_in_native_trans state (such as from 2046 // check_special_condition_for_native_trans()). 2047 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2048 2049 if (has_last_Java_frame() && has_async_condition()) { 2050 // If we are at a polling page safepoint (not a poll return) 2051 // then we must defer async exception because live registers 2052 // will be clobbered by the exception path. Poll return is 2053 // ok because the call we a returning from already collides 2054 // with exception handling registers and so there is no issue. 2055 // (The exception handling path kills call result registers but 2056 // this is ok since the exception kills the result anyway). 2057 2058 if (is_at_poll_safepoint()) { 2059 // if the code we are returning to has deoptimized we must defer 2060 // the exception otherwise live registers get clobbered on the 2061 // exception path before deoptimization is able to retrieve them. 2062 // 2063 RegisterMap map(this, false); 2064 frame caller_fr = last_frame().sender(&map); 2065 assert(caller_fr.is_compiled_frame(), "what?"); 2066 if (caller_fr.is_deoptimized_frame()) { 2067 if (TraceExceptions) { 2068 ResourceMark rm; 2069 tty->print_cr("deferred async exception at compiled safepoint"); 2070 } 2071 return; 2072 } 2073 } 2074 } 2075 2076 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2077 if (condition == _no_async_condition) { 2078 // Conditions have changed since has_special_runtime_exit_condition() 2079 // was called: 2080 // - if we were here only because of an external suspend request, 2081 // then that was taken care of above (or cancelled) so we are done 2082 // - if we were here because of another async request, then it has 2083 // been cleared between the has_special_runtime_exit_condition() 2084 // and now so again we are done 2085 return; 2086 } 2087 2088 // Check for pending async. exception 2089 if (_pending_async_exception != NULL) { 2090 // Only overwrite an already pending exception, if it is not a threadDeath. 2091 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2092 2093 // We cannot call Exceptions::_throw(...) here because we cannot block 2094 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2095 2096 if (TraceExceptions) { 2097 ResourceMark rm; 2098 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2099 if (has_last_Java_frame() ) { 2100 frame f = last_frame(); 2101 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2102 } 2103 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2104 } 2105 _pending_async_exception = NULL; 2106 clear_has_async_exception(); 2107 } 2108 } 2109 2110 if (check_unsafe_error && 2111 condition == _async_unsafe_access_error && !has_pending_exception()) { 2112 condition = _no_async_condition; // done 2113 switch (thread_state()) { 2114 case _thread_in_vm: 2115 { 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_native: 2120 { 2121 ThreadInVMfromNative tiv(this); 2122 JavaThread* THREAD = this; 2123 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2124 } 2125 case _thread_in_Java: 2126 { 2127 ThreadInVMfromJava tiv(this); 2128 JavaThread* THREAD = this; 2129 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2130 } 2131 default: 2132 ShouldNotReachHere(); 2133 } 2134 } 2135 2136 assert(condition == _no_async_condition || has_pending_exception() || 2137 (!check_unsafe_error && condition == _async_unsafe_access_error), 2138 "must have handled the async condition, if no exception"); 2139 } 2140 2141 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2142 // 2143 // Check for pending external suspend. Internal suspend requests do 2144 // not use handle_special_runtime_exit_condition(). 2145 // If JNIEnv proxies are allowed, don't self-suspend if the target 2146 // thread is not the current thread. In older versions of jdbx, jdbx 2147 // threads could call into the VM with another thread's JNIEnv so we 2148 // can be here operating on behalf of a suspended thread (4432884). 2149 bool do_self_suspend = is_external_suspend_with_lock(); 2150 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2151 // 2152 // Because thread is external suspended the safepoint code will count 2153 // thread as at a safepoint. This can be odd because we can be here 2154 // as _thread_in_Java which would normally transition to _thread_blocked 2155 // at a safepoint. We would like to mark the thread as _thread_blocked 2156 // before calling java_suspend_self like all other callers of it but 2157 // we must then observe proper safepoint protocol. (We can't leave 2158 // _thread_blocked with a safepoint in progress). However we can be 2159 // here as _thread_in_native_trans so we can't use a normal transition 2160 // constructor/destructor pair because they assert on that type of 2161 // transition. We could do something like: 2162 // 2163 // JavaThreadState state = thread_state(); 2164 // set_thread_state(_thread_in_vm); 2165 // { 2166 // ThreadBlockInVM tbivm(this); 2167 // java_suspend_self() 2168 // } 2169 // set_thread_state(_thread_in_vm_trans); 2170 // if (safepoint) block; 2171 // set_thread_state(state); 2172 // 2173 // but that is pretty messy. Instead we just go with the way the 2174 // code has worked before and note that this is the only path to 2175 // java_suspend_self that doesn't put the thread in _thread_blocked 2176 // mode. 2177 2178 frame_anchor()->make_walkable(this); 2179 java_suspend_self(); 2180 2181 // We might be here for reasons in addition to the self-suspend request 2182 // so check for other async requests. 2183 } 2184 2185 if (check_asyncs) { 2186 check_and_handle_async_exceptions(); 2187 } 2188 } 2189 2190 void JavaThread::send_thread_stop(oop java_throwable) { 2191 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2192 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2193 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2194 2195 // Do not throw asynchronous exceptions against the compiler thread 2196 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2197 if (is_Compiler_thread()) return; 2198 2199 { 2200 // Actually throw the Throwable against the target Thread - however 2201 // only if there is no thread death exception installed already. 2202 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2203 // If the topmost frame is a runtime stub, then we are calling into 2204 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2205 // must deoptimize the caller before continuing, as the compiled exception handler table 2206 // may not be valid 2207 if (has_last_Java_frame()) { 2208 frame f = last_frame(); 2209 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2210 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2211 RegisterMap reg_map(this, UseBiasedLocking); 2212 frame compiled_frame = f.sender(®_map); 2213 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2214 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2215 } 2216 } 2217 } 2218 2219 // Set async. pending exception in thread. 2220 set_pending_async_exception(java_throwable); 2221 2222 if (TraceExceptions) { 2223 ResourceMark rm; 2224 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2225 } 2226 // for AbortVMOnException flag 2227 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2228 } 2229 } 2230 2231 2232 // Interrupt thread so it will wake up from a potential wait() 2233 Thread::interrupt(this); 2234 } 2235 2236 // External suspension mechanism. 2237 // 2238 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2239 // to any VM_locks and it is at a transition 2240 // Self-suspension will happen on the transition out of the vm. 2241 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2242 // 2243 // Guarantees on return: 2244 // + Target thread will not execute any new bytecode (that's why we need to 2245 // force a safepoint) 2246 // + Target thread will not enter any new monitors 2247 // 2248 void JavaThread::java_suspend() { 2249 { MutexLocker mu(Threads_lock); 2250 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2251 return; 2252 } 2253 } 2254 2255 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2256 if (!is_external_suspend()) { 2257 // a racing resume has cancelled us; bail out now 2258 return; 2259 } 2260 2261 // suspend is done 2262 uint32_t debug_bits = 0; 2263 // Warning: is_ext_suspend_completed() may temporarily drop the 2264 // SR_lock to allow the thread to reach a stable thread state if 2265 // it is currently in a transient thread state. 2266 if (is_ext_suspend_completed(false /* !called_by_wait */, 2267 SuspendRetryDelay, &debug_bits) ) { 2268 return; 2269 } 2270 } 2271 2272 VM_ForceSafepoint vm_suspend; 2273 VMThread::execute(&vm_suspend); 2274 } 2275 2276 // Part II of external suspension. 2277 // A JavaThread self suspends when it detects a pending external suspend 2278 // request. This is usually on transitions. It is also done in places 2279 // where continuing to the next transition would surprise the caller, 2280 // e.g., monitor entry. 2281 // 2282 // Returns the number of times that the thread self-suspended. 2283 // 2284 // Note: DO NOT call java_suspend_self() when you just want to block current 2285 // thread. java_suspend_self() is the second stage of cooperative 2286 // suspension for external suspend requests and should only be used 2287 // to complete an external suspend request. 2288 // 2289 int JavaThread::java_suspend_self() { 2290 int ret = 0; 2291 2292 // we are in the process of exiting so don't suspend 2293 if (is_exiting()) { 2294 clear_external_suspend(); 2295 return ret; 2296 } 2297 2298 assert(_anchor.walkable() || 2299 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2300 "must have walkable stack"); 2301 2302 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2303 2304 assert(!this->is_ext_suspended(), 2305 "a thread trying to self-suspend should not already be suspended"); 2306 2307 if (this->is_suspend_equivalent()) { 2308 // If we are self-suspending as a result of the lifting of a 2309 // suspend equivalent condition, then the suspend_equivalent 2310 // flag is not cleared until we set the ext_suspended flag so 2311 // that wait_for_ext_suspend_completion() returns consistent 2312 // results. 2313 this->clear_suspend_equivalent(); 2314 } 2315 2316 // A racing resume may have cancelled us before we grabbed SR_lock 2317 // above. Or another external suspend request could be waiting for us 2318 // by the time we return from SR_lock()->wait(). The thread 2319 // that requested the suspension may already be trying to walk our 2320 // stack and if we return now, we can change the stack out from under 2321 // it. This would be a "bad thing (TM)" and cause the stack walker 2322 // to crash. We stay self-suspended until there are no more pending 2323 // external suspend requests. 2324 while (is_external_suspend()) { 2325 ret++; 2326 this->set_ext_suspended(); 2327 2328 // _ext_suspended flag is cleared by java_resume() 2329 while (is_ext_suspended()) { 2330 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2331 } 2332 } 2333 2334 return ret; 2335 } 2336 2337 #ifdef ASSERT 2338 // verify the JavaThread has not yet been published in the Threads::list, and 2339 // hence doesn't need protection from concurrent access at this stage 2340 void JavaThread::verify_not_published() { 2341 if (!Threads_lock->owned_by_self()) { 2342 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2343 assert( !Threads::includes(this), 2344 "java thread shouldn't have been published yet!"); 2345 } 2346 else { 2347 assert( !Threads::includes(this), 2348 "java thread shouldn't have been published yet!"); 2349 } 2350 } 2351 #endif 2352 2353 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2354 // progress or when _suspend_flags is non-zero. 2355 // Current thread needs to self-suspend if there is a suspend request and/or 2356 // block if a safepoint is in progress. 2357 // Async exception ISN'T checked. 2358 // Note only the ThreadInVMfromNative transition can call this function 2359 // directly and when thread state is _thread_in_native_trans 2360 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2361 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2362 2363 JavaThread *curJT = JavaThread::current(); 2364 bool do_self_suspend = thread->is_external_suspend(); 2365 2366 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2367 2368 // If JNIEnv proxies are allowed, don't self-suspend if the target 2369 // thread is not the current thread. In older versions of jdbx, jdbx 2370 // threads could call into the VM with another thread's JNIEnv so we 2371 // can be here operating on behalf of a suspended thread (4432884). 2372 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2373 JavaThreadState state = thread->thread_state(); 2374 2375 // We mark this thread_blocked state as a suspend-equivalent so 2376 // that a caller to is_ext_suspend_completed() won't be confused. 2377 // The suspend-equivalent state is cleared by java_suspend_self(). 2378 thread->set_suspend_equivalent(); 2379 2380 // If the safepoint code sees the _thread_in_native_trans state, it will 2381 // wait until the thread changes to other thread state. There is no 2382 // guarantee on how soon we can obtain the SR_lock and complete the 2383 // self-suspend request. It would be a bad idea to let safepoint wait for 2384 // too long. Temporarily change the state to _thread_blocked to 2385 // let the VM thread know that this thread is ready for GC. The problem 2386 // of changing thread state is that safepoint could happen just after 2387 // java_suspend_self() returns after being resumed, and VM thread will 2388 // see the _thread_blocked state. We must check for safepoint 2389 // after restoring the state and make sure we won't leave while a safepoint 2390 // is in progress. 2391 thread->set_thread_state(_thread_blocked); 2392 thread->java_suspend_self(); 2393 thread->set_thread_state(state); 2394 // Make sure new state is seen by VM thread 2395 if (os::is_MP()) { 2396 if (UseMembar) { 2397 // Force a fence between the write above and read below 2398 OrderAccess::fence(); 2399 } else { 2400 // Must use this rather than serialization page in particular on Windows 2401 InterfaceSupport::serialize_memory(thread); 2402 } 2403 } 2404 } 2405 2406 if (SafepointSynchronize::do_call_back()) { 2407 // If we are safepointing, then block the caller which may not be 2408 // the same as the target thread (see above). 2409 SafepointSynchronize::block(curJT); 2410 } 2411 2412 if (thread->is_deopt_suspend()) { 2413 thread->clear_deopt_suspend(); 2414 RegisterMap map(thread, false); 2415 frame f = thread->last_frame(); 2416 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2417 f = f.sender(&map); 2418 } 2419 if (f.id() == thread->must_deopt_id()) { 2420 thread->clear_must_deopt_id(); 2421 f.deoptimize(thread); 2422 } else { 2423 fatal("missed deoptimization!"); 2424 } 2425 } 2426 } 2427 2428 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2429 // progress or when _suspend_flags is non-zero. 2430 // Current thread needs to self-suspend if there is a suspend request and/or 2431 // block if a safepoint is in progress. 2432 // Also check for pending async exception (not including unsafe access error). 2433 // Note only the native==>VM/Java barriers can call this function and when 2434 // thread state is _thread_in_native_trans. 2435 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2436 check_safepoint_and_suspend_for_native_trans(thread); 2437 2438 if (thread->has_async_exception()) { 2439 // We are in _thread_in_native_trans state, don't handle unsafe 2440 // access error since that may block. 2441 thread->check_and_handle_async_exceptions(false); 2442 } 2443 } 2444 2445 // This is a variant of the normal 2446 // check_special_condition_for_native_trans with slightly different 2447 // semantics for use by critical native wrappers. It does all the 2448 // normal checks but also performs the transition back into 2449 // thread_in_Java state. This is required so that critical natives 2450 // can potentially block and perform a GC if they are the last thread 2451 // exiting the GC_locker. 2452 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2453 check_special_condition_for_native_trans(thread); 2454 2455 // Finish the transition 2456 thread->set_thread_state(_thread_in_Java); 2457 2458 if (thread->do_critical_native_unlock()) { 2459 ThreadInVMfromJavaNoAsyncException tiv(thread); 2460 GC_locker::unlock_critical(thread); 2461 thread->clear_critical_native_unlock(); 2462 } 2463 } 2464 2465 // We need to guarantee the Threads_lock here, since resumes are not 2466 // allowed during safepoint synchronization 2467 // Can only resume from an external suspension 2468 void JavaThread::java_resume() { 2469 assert_locked_or_safepoint(Threads_lock); 2470 2471 // Sanity check: thread is gone, has started exiting or the thread 2472 // was not externally suspended. 2473 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2474 return; 2475 } 2476 2477 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2478 2479 clear_external_suspend(); 2480 2481 if (is_ext_suspended()) { 2482 clear_ext_suspended(); 2483 SR_lock()->notify_all(); 2484 } 2485 } 2486 2487 void JavaThread::create_stack_guard_pages() { 2488 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2489 address low_addr = stack_base() - stack_size(); 2490 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2491 2492 int allocate = os::allocate_stack_guard_pages(); 2493 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2494 2495 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2496 warning("Attempt to allocate stack guard pages failed."); 2497 return; 2498 } 2499 2500 if (os::guard_memory((char *) low_addr, len)) { 2501 _stack_guard_state = stack_guard_enabled; 2502 } else { 2503 warning("Attempt to protect stack guard pages failed."); 2504 if (os::uncommit_memory((char *) low_addr, len)) { 2505 warning("Attempt to deallocate stack guard pages failed."); 2506 } 2507 } 2508 } 2509 2510 void JavaThread::remove_stack_guard_pages() { 2511 assert(Thread::current() == this, "from different thread"); 2512 if (_stack_guard_state == stack_guard_unused) return; 2513 address low_addr = stack_base() - stack_size(); 2514 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2515 2516 if (os::allocate_stack_guard_pages()) { 2517 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2518 _stack_guard_state = stack_guard_unused; 2519 } else { 2520 warning("Attempt to deallocate stack guard pages failed."); 2521 } 2522 } else { 2523 if (_stack_guard_state == stack_guard_unused) return; 2524 if (os::unguard_memory((char *) low_addr, len)) { 2525 _stack_guard_state = stack_guard_unused; 2526 } else { 2527 warning("Attempt to unprotect stack guard pages failed."); 2528 } 2529 } 2530 } 2531 2532 void JavaThread::enable_stack_yellow_zone() { 2533 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2534 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2535 2536 // The base notation is from the stacks point of view, growing downward. 2537 // We need to adjust it to work correctly with guard_memory() 2538 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2539 2540 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2541 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2542 2543 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2544 _stack_guard_state = stack_guard_enabled; 2545 } else { 2546 warning("Attempt to guard stack yellow zone failed."); 2547 } 2548 enable_register_stack_guard(); 2549 } 2550 2551 void JavaThread::disable_stack_yellow_zone() { 2552 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2553 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2554 2555 // Simply return if called for a thread that does not use guard pages. 2556 if (_stack_guard_state == stack_guard_unused) return; 2557 2558 // The base notation is from the stacks point of view, growing downward. 2559 // We need to adjust it to work correctly with guard_memory() 2560 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2561 2562 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2563 _stack_guard_state = stack_guard_yellow_disabled; 2564 } else { 2565 warning("Attempt to unguard stack yellow zone failed."); 2566 } 2567 disable_register_stack_guard(); 2568 } 2569 2570 void JavaThread::enable_stack_red_zone() { 2571 // The base notation is from the stacks point of view, growing downward. 2572 // We need to adjust it to work correctly with guard_memory() 2573 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2574 address base = stack_red_zone_base() - stack_red_zone_size(); 2575 2576 guarantee(base < stack_base(),"Error calculating stack red zone"); 2577 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2578 2579 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2580 warning("Attempt to guard stack red zone failed."); 2581 } 2582 } 2583 2584 void JavaThread::disable_stack_red_zone() { 2585 // The base notation is from the stacks point of view, growing downward. 2586 // We need to adjust it to work correctly with guard_memory() 2587 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2588 address base = stack_red_zone_base() - stack_red_zone_size(); 2589 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2590 warning("Attempt to unguard stack red zone failed."); 2591 } 2592 } 2593 2594 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2595 // ignore is there is no stack 2596 if (!has_last_Java_frame()) return; 2597 // traverse the stack frames. Starts from top frame. 2598 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2599 frame* fr = fst.current(); 2600 f(fr, fst.register_map()); 2601 } 2602 } 2603 2604 2605 #ifndef PRODUCT 2606 // Deoptimization 2607 // Function for testing deoptimization 2608 void JavaThread::deoptimize() { 2609 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2610 StackFrameStream fst(this, UseBiasedLocking); 2611 bool deopt = false; // Dump stack only if a deopt actually happens. 2612 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2613 // Iterate over all frames in the thread and deoptimize 2614 for(; !fst.is_done(); fst.next()) { 2615 if(fst.current()->can_be_deoptimized()) { 2616 2617 if (only_at) { 2618 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2619 // consists of comma or carriage return separated numbers so 2620 // search for the current bci in that string. 2621 address pc = fst.current()->pc(); 2622 nmethod* nm = (nmethod*) fst.current()->cb(); 2623 ScopeDesc* sd = nm->scope_desc_at( pc); 2624 char buffer[8]; 2625 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2626 size_t len = strlen(buffer); 2627 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2628 while (found != NULL) { 2629 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2630 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2631 // Check that the bci found is bracketed by terminators. 2632 break; 2633 } 2634 found = strstr(found + 1, buffer); 2635 } 2636 if (!found) { 2637 continue; 2638 } 2639 } 2640 2641 if (DebugDeoptimization && !deopt) { 2642 deopt = true; // One-time only print before deopt 2643 tty->print_cr("[BEFORE Deoptimization]"); 2644 trace_frames(); 2645 trace_stack(); 2646 } 2647 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2648 } 2649 } 2650 2651 if (DebugDeoptimization && deopt) { 2652 tty->print_cr("[AFTER Deoptimization]"); 2653 trace_frames(); 2654 } 2655 } 2656 2657 2658 // Make zombies 2659 void JavaThread::make_zombies() { 2660 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2661 if (fst.current()->can_be_deoptimized()) { 2662 // it is a Java nmethod 2663 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2664 nm->make_not_entrant(); 2665 } 2666 } 2667 } 2668 #endif // PRODUCT 2669 2670 2671 void JavaThread::deoptimized_wrt_marked_nmethods() { 2672 if (!has_last_Java_frame()) return; 2673 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2674 StackFrameStream fst(this, UseBiasedLocking); 2675 for(; !fst.is_done(); fst.next()) { 2676 if (fst.current()->should_be_deoptimized()) { 2677 if (LogCompilation && xtty != NULL) { 2678 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2679 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2680 this->name(), nm != NULL ? nm->compile_id() : -1); 2681 } 2682 2683 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2684 } 2685 } 2686 } 2687 2688 2689 // GC support 2690 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2691 2692 void JavaThread::gc_epilogue() { 2693 frames_do(frame_gc_epilogue); 2694 } 2695 2696 2697 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2698 2699 void JavaThread::gc_prologue() { 2700 frames_do(frame_gc_prologue); 2701 } 2702 2703 // If the caller is a NamedThread, then remember, in the current scope, 2704 // the given JavaThread in its _processed_thread field. 2705 class RememberProcessedThread: public StackObj { 2706 NamedThread* _cur_thr; 2707 public: 2708 RememberProcessedThread(JavaThread* jthr) { 2709 Thread* thread = Thread::current(); 2710 if (thread->is_Named_thread()) { 2711 _cur_thr = (NamedThread *)thread; 2712 _cur_thr->set_processed_thread(jthr); 2713 } else { 2714 _cur_thr = NULL; 2715 } 2716 } 2717 2718 ~RememberProcessedThread() { 2719 if (_cur_thr) { 2720 _cur_thr->set_processed_thread(NULL); 2721 } 2722 } 2723 }; 2724 2725 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2726 // Verify that the deferred card marks have been flushed. 2727 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2728 2729 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2730 // since there may be more than one thread using each ThreadProfiler. 2731 2732 // Traverse the GCHandles 2733 Thread::oops_do(f, cld_f, cf); 2734 2735 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2736 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2737 2738 if (has_last_Java_frame()) { 2739 // Record JavaThread to GC thread 2740 RememberProcessedThread rpt(this); 2741 2742 // Traverse the privileged stack 2743 if (_privileged_stack_top != NULL) { 2744 _privileged_stack_top->oops_do(f); 2745 } 2746 2747 // traverse the registered growable array 2748 if (_array_for_gc != NULL) { 2749 for (int index = 0; index < _array_for_gc->length(); index++) { 2750 f->do_oop(_array_for_gc->adr_at(index)); 2751 } 2752 } 2753 2754 // Traverse the monitor chunks 2755 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2756 chunk->oops_do(f); 2757 } 2758 2759 // Traverse the execution stack 2760 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2761 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2762 } 2763 } 2764 2765 // callee_target is never live across a gc point so NULL it here should 2766 // it still contain a methdOop. 2767 2768 set_callee_target(NULL); 2769 2770 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2771 // If we have deferred set_locals there might be oops waiting to be 2772 // written 2773 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2774 if (list != NULL) { 2775 for (int i = 0; i < list->length(); i++) { 2776 list->at(i)->oops_do(f); 2777 } 2778 } 2779 2780 // Traverse instance variables at the end since the GC may be moving things 2781 // around using this function 2782 f->do_oop((oop*) &_threadObj); 2783 f->do_oop((oop*) &_vm_result); 2784 f->do_oop((oop*) &_exception_oop); 2785 f->do_oop((oop*) &_pending_async_exception); 2786 2787 if (jvmti_thread_state() != NULL) { 2788 jvmti_thread_state()->oops_do(f); 2789 } 2790 } 2791 2792 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2793 Thread::nmethods_do(cf); // (super method is a no-op) 2794 2795 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2796 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2797 2798 if (has_last_Java_frame()) { 2799 // Traverse the execution stack 2800 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2801 fst.current()->nmethods_do(cf); 2802 } 2803 } 2804 } 2805 2806 void JavaThread::metadata_do(void f(Metadata*)) { 2807 Thread::metadata_do(f); 2808 if (has_last_Java_frame()) { 2809 // Traverse the execution stack to call f() on the methods in the stack 2810 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2811 fst.current()->metadata_do(f); 2812 } 2813 } else if (is_Compiler_thread()) { 2814 // need to walk ciMetadata in current compile tasks to keep alive. 2815 CompilerThread* ct = (CompilerThread*)this; 2816 if (ct->env() != NULL) { 2817 ct->env()->metadata_do(f); 2818 } 2819 } 2820 } 2821 2822 // Printing 2823 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2824 switch (_thread_state) { 2825 case _thread_uninitialized: return "_thread_uninitialized"; 2826 case _thread_new: return "_thread_new"; 2827 case _thread_new_trans: return "_thread_new_trans"; 2828 case _thread_in_native: return "_thread_in_native"; 2829 case _thread_in_native_trans: return "_thread_in_native_trans"; 2830 case _thread_in_vm: return "_thread_in_vm"; 2831 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2832 case _thread_in_Java: return "_thread_in_Java"; 2833 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2834 case _thread_blocked: return "_thread_blocked"; 2835 case _thread_blocked_trans: return "_thread_blocked_trans"; 2836 default: return "unknown thread state"; 2837 } 2838 } 2839 2840 #ifndef PRODUCT 2841 void JavaThread::print_thread_state_on(outputStream *st) const { 2842 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2843 }; 2844 void JavaThread::print_thread_state() const { 2845 print_thread_state_on(tty); 2846 }; 2847 #endif // PRODUCT 2848 2849 // Called by Threads::print() for VM_PrintThreads operation 2850 void JavaThread::print_on(outputStream *st) const { 2851 st->print("\"%s\" ", get_thread_name()); 2852 oop thread_oop = threadObj(); 2853 if (thread_oop != NULL) { 2854 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2855 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2856 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2857 } 2858 Thread::print_on(st); 2859 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2860 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2861 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2862 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2863 } 2864 #ifndef PRODUCT 2865 print_thread_state_on(st); 2866 _safepoint_state->print_on(st); 2867 #endif // PRODUCT 2868 } 2869 2870 // Called by fatal error handler. The difference between this and 2871 // JavaThread::print() is that we can't grab lock or allocate memory. 2872 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2873 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2874 oop thread_obj = threadObj(); 2875 if (thread_obj != NULL) { 2876 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2877 } 2878 st->print(" ["); 2879 st->print("%s", _get_thread_state_name(_thread_state)); 2880 if (osthread()) { 2881 st->print(", id=%d", osthread()->thread_id()); 2882 } 2883 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2884 _stack_base - _stack_size, _stack_base); 2885 st->print("]"); 2886 return; 2887 } 2888 2889 // Verification 2890 2891 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2892 2893 void JavaThread::verify() { 2894 // Verify oops in the thread. 2895 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2896 2897 // Verify the stack frames. 2898 frames_do(frame_verify); 2899 } 2900 2901 // CR 6300358 (sub-CR 2137150) 2902 // Most callers of this method assume that it can't return NULL but a 2903 // thread may not have a name whilst it is in the process of attaching to 2904 // the VM - see CR 6412693, and there are places where a JavaThread can be 2905 // seen prior to having it's threadObj set (eg JNI attaching threads and 2906 // if vm exit occurs during initialization). These cases can all be accounted 2907 // for such that this method never returns NULL. 2908 const char* JavaThread::get_thread_name() const { 2909 #ifdef ASSERT 2910 // early safepoints can hit while current thread does not yet have TLS 2911 if (!SafepointSynchronize::is_at_safepoint()) { 2912 Thread *cur = Thread::current(); 2913 if (!(cur->is_Java_thread() && cur == this)) { 2914 // Current JavaThreads are allowed to get their own name without 2915 // the Threads_lock. 2916 assert_locked_or_safepoint(Threads_lock); 2917 } 2918 } 2919 #endif // ASSERT 2920 return get_thread_name_string(); 2921 } 2922 2923 // Returns a non-NULL representation of this thread's name, or a suitable 2924 // descriptive string if there is no set name 2925 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2926 const char* name_str; 2927 oop thread_obj = threadObj(); 2928 if (thread_obj != NULL) { 2929 oop name = java_lang_Thread::name(thread_obj); 2930 if (name != NULL) { 2931 if (buf == NULL) { 2932 name_str = java_lang_String::as_utf8_string(name); 2933 } 2934 else { 2935 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 2936 } 2937 } 2938 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2939 name_str = "<no-name - thread is attaching>"; 2940 } 2941 else { 2942 name_str = Thread::name(); 2943 } 2944 } 2945 else { 2946 name_str = Thread::name(); 2947 } 2948 assert(name_str != NULL, "unexpected NULL thread name"); 2949 return name_str; 2950 } 2951 2952 2953 const char* JavaThread::get_threadgroup_name() const { 2954 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2955 oop thread_obj = threadObj(); 2956 if (thread_obj != NULL) { 2957 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2958 if (thread_group != NULL) { 2959 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2960 // ThreadGroup.name can be null 2961 if (name != NULL) { 2962 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2963 return str; 2964 } 2965 } 2966 } 2967 return NULL; 2968 } 2969 2970 const char* JavaThread::get_parent_name() const { 2971 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2972 oop thread_obj = threadObj(); 2973 if (thread_obj != NULL) { 2974 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2975 if (thread_group != NULL) { 2976 oop parent = java_lang_ThreadGroup::parent(thread_group); 2977 if (parent != NULL) { 2978 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2979 // ThreadGroup.name can be null 2980 if (name != NULL) { 2981 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2982 return str; 2983 } 2984 } 2985 } 2986 } 2987 return NULL; 2988 } 2989 2990 ThreadPriority JavaThread::java_priority() const { 2991 oop thr_oop = threadObj(); 2992 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2993 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2994 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2995 return priority; 2996 } 2997 2998 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2999 3000 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3001 // Link Java Thread object <-> C++ Thread 3002 3003 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3004 // and put it into a new Handle. The Handle "thread_oop" can then 3005 // be used to pass the C++ thread object to other methods. 3006 3007 // Set the Java level thread object (jthread) field of the 3008 // new thread (a JavaThread *) to C++ thread object using the 3009 // "thread_oop" handle. 3010 3011 // Set the thread field (a JavaThread *) of the 3012 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3013 3014 Handle thread_oop(Thread::current(), 3015 JNIHandles::resolve_non_null(jni_thread)); 3016 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3017 "must be initialized"); 3018 set_threadObj(thread_oop()); 3019 java_lang_Thread::set_thread(thread_oop(), this); 3020 3021 if (prio == NoPriority) { 3022 prio = java_lang_Thread::priority(thread_oop()); 3023 assert(prio != NoPriority, "A valid priority should be present"); 3024 } 3025 3026 // Push the Java priority down to the native thread; needs Threads_lock 3027 Thread::set_priority(this, prio); 3028 3029 prepare_ext(); 3030 3031 // Add the new thread to the Threads list and set it in motion. 3032 // We must have threads lock in order to call Threads::add. 3033 // It is crucial that we do not block before the thread is 3034 // added to the Threads list for if a GC happens, then the java_thread oop 3035 // will not be visited by GC. 3036 Threads::add(this); 3037 } 3038 3039 oop JavaThread::current_park_blocker() { 3040 // Support for JSR-166 locks 3041 oop thread_oop = threadObj(); 3042 if (thread_oop != NULL && 3043 JDK_Version::current().supports_thread_park_blocker()) { 3044 return java_lang_Thread::park_blocker(thread_oop); 3045 } 3046 return NULL; 3047 } 3048 3049 3050 void JavaThread::print_stack_on(outputStream* st) { 3051 if (!has_last_Java_frame()) return; 3052 ResourceMark rm; 3053 HandleMark hm; 3054 3055 RegisterMap reg_map(this); 3056 vframe* start_vf = last_java_vframe(®_map); 3057 int count = 0; 3058 for (vframe* f = start_vf; f; f = f->sender() ) { 3059 if (f->is_java_frame()) { 3060 javaVFrame* jvf = javaVFrame::cast(f); 3061 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3062 3063 // Print out lock information 3064 if (JavaMonitorsInStackTrace) { 3065 jvf->print_lock_info_on(st, count); 3066 } 3067 } else { 3068 // Ignore non-Java frames 3069 } 3070 3071 // Bail-out case for too deep stacks 3072 count++; 3073 if (MaxJavaStackTraceDepth == count) return; 3074 } 3075 } 3076 3077 3078 // JVMTI PopFrame support 3079 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3080 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3081 if (in_bytes(size_in_bytes) != 0) { 3082 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3083 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3084 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3085 } 3086 } 3087 3088 void* JavaThread::popframe_preserved_args() { 3089 return _popframe_preserved_args; 3090 } 3091 3092 ByteSize JavaThread::popframe_preserved_args_size() { 3093 return in_ByteSize(_popframe_preserved_args_size); 3094 } 3095 3096 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3097 int sz = in_bytes(popframe_preserved_args_size()); 3098 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3099 return in_WordSize(sz / wordSize); 3100 } 3101 3102 void JavaThread::popframe_free_preserved_args() { 3103 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3104 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3105 _popframe_preserved_args = NULL; 3106 _popframe_preserved_args_size = 0; 3107 } 3108 3109 #ifndef PRODUCT 3110 3111 void JavaThread::trace_frames() { 3112 tty->print_cr("[Describe stack]"); 3113 int frame_no = 1; 3114 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3115 tty->print(" %d. ", frame_no++); 3116 fst.current()->print_value_on(tty,this); 3117 tty->cr(); 3118 } 3119 } 3120 3121 class PrintAndVerifyOopClosure: public OopClosure { 3122 protected: 3123 template <class T> inline void do_oop_work(T* p) { 3124 oop obj = oopDesc::load_decode_heap_oop(p); 3125 if (obj == NULL) return; 3126 tty->print(INTPTR_FORMAT ": ", p); 3127 if (obj->is_oop_or_null()) { 3128 if (obj->is_objArray()) { 3129 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3130 } else { 3131 obj->print(); 3132 } 3133 } else { 3134 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3135 } 3136 tty->cr(); 3137 } 3138 public: 3139 virtual void do_oop(oop* p) { do_oop_work(p); } 3140 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3141 }; 3142 3143 3144 static void oops_print(frame* f, const RegisterMap *map) { 3145 PrintAndVerifyOopClosure print; 3146 f->print_value(); 3147 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3148 } 3149 3150 // Print our all the locations that contain oops and whether they are 3151 // valid or not. This useful when trying to find the oldest frame 3152 // where an oop has gone bad since the frame walk is from youngest to 3153 // oldest. 3154 void JavaThread::trace_oops() { 3155 tty->print_cr("[Trace oops]"); 3156 frames_do(oops_print); 3157 } 3158 3159 3160 #ifdef ASSERT 3161 // Print or validate the layout of stack frames 3162 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3163 ResourceMark rm; 3164 PRESERVE_EXCEPTION_MARK; 3165 FrameValues values; 3166 int frame_no = 0; 3167 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3168 fst.current()->describe(values, ++frame_no); 3169 if (depth == frame_no) break; 3170 } 3171 if (validate_only) { 3172 values.validate(); 3173 } else { 3174 tty->print_cr("[Describe stack layout]"); 3175 values.print(this); 3176 } 3177 } 3178 #endif 3179 3180 void JavaThread::trace_stack_from(vframe* start_vf) { 3181 ResourceMark rm; 3182 int vframe_no = 1; 3183 for (vframe* f = start_vf; f; f = f->sender() ) { 3184 if (f->is_java_frame()) { 3185 javaVFrame::cast(f)->print_activation(vframe_no++); 3186 } else { 3187 f->print(); 3188 } 3189 if (vframe_no > StackPrintLimit) { 3190 tty->print_cr("...<more frames>..."); 3191 return; 3192 } 3193 } 3194 } 3195 3196 3197 void JavaThread::trace_stack() { 3198 if (!has_last_Java_frame()) return; 3199 ResourceMark rm; 3200 HandleMark hm; 3201 RegisterMap reg_map(this); 3202 trace_stack_from(last_java_vframe(®_map)); 3203 } 3204 3205 3206 #endif // PRODUCT 3207 3208 3209 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3210 assert(reg_map != NULL, "a map must be given"); 3211 frame f = last_frame(); 3212 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3213 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3214 } 3215 return NULL; 3216 } 3217 3218 3219 Klass* JavaThread::security_get_caller_class(int depth) { 3220 vframeStream vfst(this); 3221 vfst.security_get_caller_frame(depth); 3222 if (!vfst.at_end()) { 3223 return vfst.method()->method_holder(); 3224 } 3225 return NULL; 3226 } 3227 3228 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3229 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3230 CompileBroker::compiler_thread_loop(); 3231 } 3232 3233 // Create a CompilerThread 3234 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3235 : JavaThread(&compiler_thread_entry) { 3236 _env = NULL; 3237 _log = NULL; 3238 _task = NULL; 3239 _queue = queue; 3240 _counters = counters; 3241 _buffer_blob = NULL; 3242 _scanned_nmethod = NULL; 3243 _compiler = NULL; 3244 3245 #ifndef PRODUCT 3246 _ideal_graph_printer = NULL; 3247 #endif 3248 } 3249 3250 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3251 JavaThread::oops_do(f, cld_f, cf); 3252 if (_scanned_nmethod != NULL && cf != NULL) { 3253 // Safepoints can occur when the sweeper is scanning an nmethod so 3254 // process it here to make sure it isn't unloaded in the middle of 3255 // a scan. 3256 cf->do_code_blob(_scanned_nmethod); 3257 } 3258 } 3259 3260 3261 // ======= Threads ======== 3262 3263 // The Threads class links together all active threads, and provides 3264 // operations over all threads. It is protected by its own Mutex 3265 // lock, which is also used in other contexts to protect thread 3266 // operations from having the thread being operated on from exiting 3267 // and going away unexpectedly (e.g., safepoint synchronization) 3268 3269 JavaThread* Threads::_thread_list = NULL; 3270 int Threads::_number_of_threads = 0; 3271 int Threads::_number_of_non_daemon_threads = 0; 3272 int Threads::_return_code = 0; 3273 size_t JavaThread::_stack_size_at_create = 0; 3274 #ifdef ASSERT 3275 bool Threads::_vm_complete = false; 3276 #endif 3277 3278 // All JavaThreads 3279 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3280 3281 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3282 void Threads::threads_do(ThreadClosure* tc) { 3283 assert_locked_or_safepoint(Threads_lock); 3284 // ALL_JAVA_THREADS iterates through all JavaThreads 3285 ALL_JAVA_THREADS(p) { 3286 tc->do_thread(p); 3287 } 3288 // Someday we could have a table or list of all non-JavaThreads. 3289 // For now, just manually iterate through them. 3290 tc->do_thread(VMThread::vm_thread()); 3291 Universe::heap()->gc_threads_do(tc); 3292 WatcherThread *wt = WatcherThread::watcher_thread(); 3293 // Strictly speaking, the following NULL check isn't sufficient to make sure 3294 // the data for WatcherThread is still valid upon being examined. However, 3295 // considering that WatchThread terminates when the VM is on the way to 3296 // exit at safepoint, the chance of the above is extremely small. The right 3297 // way to prevent termination of WatcherThread would be to acquire 3298 // Terminator_lock, but we can't do that without violating the lock rank 3299 // checking in some cases. 3300 if (wt != NULL) 3301 tc->do_thread(wt); 3302 3303 // If CompilerThreads ever become non-JavaThreads, add them here 3304 } 3305 3306 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3307 3308 extern void JDK_Version_init(); 3309 3310 // Preinitialize version info. 3311 VM_Version::early_initialize(); 3312 3313 // Check version 3314 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3315 3316 // Initialize the output stream module 3317 ostream_init(); 3318 3319 // Process java launcher properties. 3320 Arguments::process_sun_java_launcher_properties(args); 3321 3322 // Initialize the os module before using TLS 3323 os::init(); 3324 3325 // Initialize system properties. 3326 Arguments::init_system_properties(); 3327 3328 // So that JDK version can be used as a discrimintor when parsing arguments 3329 JDK_Version_init(); 3330 3331 // Update/Initialize System properties after JDK version number is known 3332 Arguments::init_version_specific_system_properties(); 3333 3334 // Parse arguments 3335 jint parse_result = Arguments::parse(args); 3336 if (parse_result != JNI_OK) return parse_result; 3337 3338 os::init_before_ergo(); 3339 3340 jint ergo_result = Arguments::apply_ergo(); 3341 if (ergo_result != JNI_OK) return ergo_result; 3342 3343 if (PauseAtStartup) { 3344 os::pause(); 3345 } 3346 3347 #ifndef USDT2 3348 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3349 #else /* USDT2 */ 3350 HOTSPOT_VM_INIT_BEGIN(); 3351 #endif /* USDT2 */ 3352 3353 // Record VM creation timing statistics 3354 TraceVmCreationTime create_vm_timer; 3355 create_vm_timer.start(); 3356 3357 // Timing (must come after argument parsing) 3358 TraceTime timer("Create VM", TraceStartupTime); 3359 3360 // Initialize the os module after parsing the args 3361 jint os_init_2_result = os::init_2(); 3362 if (os_init_2_result != JNI_OK) return os_init_2_result; 3363 3364 jint adjust_after_os_result = Arguments::adjust_after_os(); 3365 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3366 3367 // intialize TLS 3368 ThreadLocalStorage::init(); 3369 3370 // Initialize output stream logging 3371 ostream_init_log(); 3372 3373 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3374 // Must be before create_vm_init_agents() 3375 if (Arguments::init_libraries_at_startup()) { 3376 convert_vm_init_libraries_to_agents(); 3377 } 3378 3379 // Launch -agentlib/-agentpath and converted -Xrun agents 3380 if (Arguments::init_agents_at_startup()) { 3381 create_vm_init_agents(); 3382 } 3383 3384 // Initialize Threads state 3385 _thread_list = NULL; 3386 _number_of_threads = 0; 3387 _number_of_non_daemon_threads = 0; 3388 3389 // Initialize global data structures and create system classes in heap 3390 vm_init_globals(); 3391 3392 // Attach the main thread to this os thread 3393 JavaThread* main_thread = new JavaThread(); 3394 main_thread->set_thread_state(_thread_in_vm); 3395 // must do this before set_active_handles and initialize_thread_local_storage 3396 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3397 // change the stack size recorded here to one based on the java thread 3398 // stacksize. This adjusted size is what is used to figure the placement 3399 // of the guard pages. 3400 main_thread->record_stack_base_and_size(); 3401 main_thread->initialize_thread_local_storage(); 3402 3403 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3404 3405 if (!main_thread->set_as_starting_thread()) { 3406 vm_shutdown_during_initialization( 3407 "Failed necessary internal allocation. Out of swap space"); 3408 delete main_thread; 3409 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3410 return JNI_ENOMEM; 3411 } 3412 3413 // Enable guard page *after* os::create_main_thread(), otherwise it would 3414 // crash Linux VM, see notes in os_linux.cpp. 3415 main_thread->create_stack_guard_pages(); 3416 3417 // Initialize Java-Level synchronization subsystem 3418 ObjectMonitor::Initialize() ; 3419 3420 // Initialize global modules 3421 jint status = init_globals(); 3422 if (status != JNI_OK) { 3423 delete main_thread; 3424 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3425 return status; 3426 } 3427 3428 // Should be done after the heap is fully created 3429 main_thread->cache_global_variables(); 3430 3431 HandleMark hm; 3432 3433 { MutexLocker mu(Threads_lock); 3434 Threads::add(main_thread); 3435 } 3436 3437 // Any JVMTI raw monitors entered in onload will transition into 3438 // real raw monitor. VM is setup enough here for raw monitor enter. 3439 JvmtiExport::transition_pending_onload_raw_monitors(); 3440 3441 // Create the VMThread 3442 { TraceTime timer("Start VMThread", TraceStartupTime); 3443 VMThread::create(); 3444 Thread* vmthread = VMThread::vm_thread(); 3445 3446 if (!os::create_thread(vmthread, os::vm_thread)) 3447 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3448 3449 // Wait for the VM thread to become ready, and VMThread::run to initialize 3450 // Monitors can have spurious returns, must always check another state flag 3451 { 3452 MutexLocker ml(Notify_lock); 3453 os::start_thread(vmthread); 3454 while (vmthread->active_handles() == NULL) { 3455 Notify_lock->wait(); 3456 } 3457 } 3458 } 3459 3460 assert (Universe::is_fully_initialized(), "not initialized"); 3461 if (VerifyDuringStartup) { 3462 // Make sure we're starting with a clean slate. 3463 VM_Verify verify_op; 3464 VMThread::execute(&verify_op); 3465 } 3466 3467 EXCEPTION_MARK; 3468 3469 // At this point, the Universe is initialized, but we have not executed 3470 // any byte code. Now is a good time (the only time) to dump out the 3471 // internal state of the JVM for sharing. 3472 if (DumpSharedSpaces) { 3473 MetaspaceShared::preload_and_dump(CHECK_0); 3474 ShouldNotReachHere(); 3475 } 3476 3477 // Always call even when there are not JVMTI environments yet, since environments 3478 // may be attached late and JVMTI must track phases of VM execution 3479 JvmtiExport::enter_start_phase(); 3480 3481 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3482 JvmtiExport::post_vm_start(); 3483 3484 { 3485 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3486 3487 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3488 create_vm_init_libraries(); 3489 } 3490 3491 initialize_class(vmSymbols::java_lang_String(), CHECK_0); 3492 3493 // Initialize java_lang.System (needed before creating the thread) 3494 initialize_class(vmSymbols::java_lang_System(), CHECK_0); 3495 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0); 3496 Handle thread_group = create_initial_thread_group(CHECK_0); 3497 Universe::set_main_thread_group(thread_group()); 3498 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0); 3499 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 3500 main_thread->set_threadObj(thread_object); 3501 // Set thread status to running since main thread has 3502 // been started and running. 3503 java_lang_Thread::set_thread_status(thread_object, 3504 java_lang_Thread::RUNNABLE); 3505 3506 // The VM creates & returns objects of this class. Make sure it's initialized. 3507 initialize_class(vmSymbols::java_lang_Class(), CHECK_0); 3508 3509 // The VM preresolves methods to these classes. Make sure that they get initialized 3510 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0); 3511 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0); 3512 call_initializeSystemClass(CHECK_0); 3513 3514 // get the Java runtime name after java.lang.System is initialized 3515 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3516 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3517 3518 // an instance of OutOfMemory exception has been allocated earlier 3519 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0); 3520 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0); 3521 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0); 3522 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0); 3523 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0); 3524 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0); 3525 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0); 3526 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0); 3527 } 3528 3529 // See : bugid 4211085. 3530 // Background : the static initializer of java.lang.Compiler tries to read 3531 // property"java.compiler" and read & write property "java.vm.info". 3532 // When a security manager is installed through the command line 3533 // option "-Djava.security.manager", the above properties are not 3534 // readable and the static initializer for java.lang.Compiler fails 3535 // resulting in a NoClassDefFoundError. This can happen in any 3536 // user code which calls methods in java.lang.Compiler. 3537 // Hack : the hack is to pre-load and initialize this class, so that only 3538 // system domains are on the stack when the properties are read. 3539 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3540 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3541 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3542 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3543 // Once that is done, we should remove this hack. 3544 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0); 3545 3546 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3547 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3548 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3549 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3550 // This should also be taken out as soon as 4211383 gets fixed. 3551 reset_vm_info_property(CHECK_0); 3552 3553 quicken_jni_functions(); 3554 3555 // Must be run after init_ft which initializes ft_enabled 3556 if (TRACE_INITIALIZE() != JNI_OK) { 3557 vm_exit_during_initialization("Failed to initialize tracing backend"); 3558 } 3559 3560 // Set flag that basic initialization has completed. Used by exceptions and various 3561 // debug stuff, that does not work until all basic classes have been initialized. 3562 set_init_completed(); 3563 3564 Metaspace::post_initialize(); 3565 3566 #ifndef USDT2 3567 HS_DTRACE_PROBE(hotspot, vm__init__end); 3568 #else /* USDT2 */ 3569 HOTSPOT_VM_INIT_END(); 3570 #endif /* USDT2 */ 3571 3572 // record VM initialization completion time 3573 #if INCLUDE_MANAGEMENT 3574 Management::record_vm_init_completed(); 3575 #endif // INCLUDE_MANAGEMENT 3576 3577 // Compute system loader. Note that this has to occur after set_init_completed, since 3578 // valid exceptions may be thrown in the process. 3579 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3580 // set_init_completed has just been called, causing exceptions not to be shortcut 3581 // anymore. We call vm_exit_during_initialization directly instead. 3582 SystemDictionary::compute_java_system_loader(THREAD); 3583 if (HAS_PENDING_EXCEPTION) { 3584 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3585 } 3586 3587 #if INCLUDE_ALL_GCS 3588 // Support for ConcurrentMarkSweep. This should be cleaned up 3589 // and better encapsulated. The ugly nested if test would go away 3590 // once things are properly refactored. XXX YSR 3591 if (UseConcMarkSweepGC || UseG1GC) { 3592 if (UseConcMarkSweepGC) { 3593 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3594 } else { 3595 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3596 } 3597 if (HAS_PENDING_EXCEPTION) { 3598 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3599 } 3600 } 3601 #endif // INCLUDE_ALL_GCS 3602 3603 // Always call even when there are not JVMTI environments yet, since environments 3604 // may be attached late and JVMTI must track phases of VM execution 3605 JvmtiExport::enter_live_phase(); 3606 3607 // Signal Dispatcher needs to be started before VMInit event is posted 3608 os::signal_init(); 3609 3610 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3611 if (!DisableAttachMechanism) { 3612 AttachListener::vm_start(); 3613 if (StartAttachListener || AttachListener::init_at_startup()) { 3614 AttachListener::init(); 3615 } 3616 } 3617 3618 // Launch -Xrun agents 3619 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3620 // back-end can launch with -Xdebug -Xrunjdwp. 3621 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3622 create_vm_init_libraries(); 3623 } 3624 3625 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3626 JvmtiExport::post_vm_initialized(); 3627 3628 if (TRACE_START() != JNI_OK) { 3629 vm_exit_during_initialization("Failed to start tracing backend."); 3630 } 3631 3632 if (CleanChunkPoolAsync) { 3633 Chunk::start_chunk_pool_cleaner_task(); 3634 } 3635 3636 // initialize compiler(s) 3637 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3638 CompileBroker::compilation_init(); 3639 #endif 3640 3641 if (EnableInvokeDynamic) { 3642 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3643 // It is done after compilers are initialized, because otherwise compilations of 3644 // signature polymorphic MH intrinsics can be missed 3645 // (see SystemDictionary::find_method_handle_intrinsic). 3646 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0); 3647 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0); 3648 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0); 3649 } 3650 3651 #if INCLUDE_MANAGEMENT 3652 Management::initialize(THREAD); 3653 #endif // INCLUDE_MANAGEMENT 3654 3655 if (HAS_PENDING_EXCEPTION) { 3656 // management agent fails to start possibly due to 3657 // configuration problem and is responsible for printing 3658 // stack trace if appropriate. Simply exit VM. 3659 vm_exit(1); 3660 } 3661 3662 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3663 if (MemProfiling) MemProfiler::engage(); 3664 StatSampler::engage(); 3665 if (CheckJNICalls) JniPeriodicChecker::engage(); 3666 3667 BiasedLocking::init(); 3668 3669 #if INCLUDE_RTM_OPT 3670 RTMLockingCounters::init(); 3671 #endif 3672 3673 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3674 call_postVMInitHook(THREAD); 3675 // The Java side of PostVMInitHook.run must deal with all 3676 // exceptions and provide means of diagnosis. 3677 if (HAS_PENDING_EXCEPTION) { 3678 CLEAR_PENDING_EXCEPTION; 3679 } 3680 } 3681 3682 { 3683 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3684 // Make sure the watcher thread can be started by WatcherThread::start() 3685 // or by dynamic enrollment. 3686 WatcherThread::make_startable(); 3687 // Start up the WatcherThread if there are any periodic tasks 3688 // NOTE: All PeriodicTasks should be registered by now. If they 3689 // aren't, late joiners might appear to start slowly (we might 3690 // take a while to process their first tick). 3691 if (PeriodicTask::num_tasks() > 0) { 3692 WatcherThread::start(); 3693 } 3694 } 3695 3696 create_vm_timer.end(); 3697 #ifdef ASSERT 3698 _vm_complete = true; 3699 #endif 3700 return JNI_OK; 3701 } 3702 3703 // type for the Agent_OnLoad and JVM_OnLoad entry points 3704 extern "C" { 3705 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3706 } 3707 // Find a command line agent library and return its entry point for 3708 // -agentlib: -agentpath: -Xrun 3709 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3710 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3711 OnLoadEntry_t on_load_entry = NULL; 3712 void *library = NULL; 3713 3714 if (!agent->valid()) { 3715 char buffer[JVM_MAXPATHLEN]; 3716 char ebuf[1024]; 3717 const char *name = agent->name(); 3718 const char *msg = "Could not find agent library "; 3719 3720 // First check to see if agent is statically linked into executable 3721 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3722 library = agent->os_lib(); 3723 } else if (agent->is_absolute_path()) { 3724 library = os::dll_load(name, ebuf, sizeof ebuf); 3725 if (library == NULL) { 3726 const char *sub_msg = " in absolute path, with error: "; 3727 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3728 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3729 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3730 // If we can't find the agent, exit. 3731 vm_exit_during_initialization(buf, NULL); 3732 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3733 } 3734 } else { 3735 // Try to load the agent from the standard dll directory 3736 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3737 name)) { 3738 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3739 } 3740 if (library == NULL) { // Try the local directory 3741 char ns[1] = {0}; 3742 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3743 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3744 } 3745 if (library == NULL) { 3746 const char *sub_msg = " on the library path, with error: "; 3747 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3748 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3749 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3750 // If we can't find the agent, exit. 3751 vm_exit_during_initialization(buf, NULL); 3752 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3753 } 3754 } 3755 } 3756 agent->set_os_lib(library); 3757 agent->set_valid(); 3758 } 3759 3760 // Find the OnLoad function. 3761 on_load_entry = 3762 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3763 false, 3764 on_load_symbols, 3765 num_symbol_entries)); 3766 return on_load_entry; 3767 } 3768 3769 // Find the JVM_OnLoad entry point 3770 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3771 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3772 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3773 } 3774 3775 // Find the Agent_OnLoad entry point 3776 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3777 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3778 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3779 } 3780 3781 // For backwards compatibility with -Xrun 3782 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3783 // treated like -agentpath: 3784 // Must be called before agent libraries are created 3785 void Threads::convert_vm_init_libraries_to_agents() { 3786 AgentLibrary* agent; 3787 AgentLibrary* next; 3788 3789 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3790 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3791 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3792 3793 // If there is an JVM_OnLoad function it will get called later, 3794 // otherwise see if there is an Agent_OnLoad 3795 if (on_load_entry == NULL) { 3796 on_load_entry = lookup_agent_on_load(agent); 3797 if (on_load_entry != NULL) { 3798 // switch it to the agent list -- so that Agent_OnLoad will be called, 3799 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3800 Arguments::convert_library_to_agent(agent); 3801 } else { 3802 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3803 } 3804 } 3805 } 3806 } 3807 3808 // Create agents for -agentlib: -agentpath: and converted -Xrun 3809 // Invokes Agent_OnLoad 3810 // Called very early -- before JavaThreads exist 3811 void Threads::create_vm_init_agents() { 3812 extern struct JavaVM_ main_vm; 3813 AgentLibrary* agent; 3814 3815 JvmtiExport::enter_onload_phase(); 3816 3817 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3818 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3819 3820 if (on_load_entry != NULL) { 3821 // Invoke the Agent_OnLoad function 3822 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3823 if (err != JNI_OK) { 3824 vm_exit_during_initialization("agent library failed to init", agent->name()); 3825 } 3826 } else { 3827 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3828 } 3829 } 3830 JvmtiExport::enter_primordial_phase(); 3831 } 3832 3833 extern "C" { 3834 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3835 } 3836 3837 void Threads::shutdown_vm_agents() { 3838 // Send any Agent_OnUnload notifications 3839 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3840 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3841 extern struct JavaVM_ main_vm; 3842 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3843 3844 // Find the Agent_OnUnload function. 3845 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3846 os::find_agent_function(agent, 3847 false, 3848 on_unload_symbols, 3849 num_symbol_entries)); 3850 3851 // Invoke the Agent_OnUnload function 3852 if (unload_entry != NULL) { 3853 JavaThread* thread = JavaThread::current(); 3854 ThreadToNativeFromVM ttn(thread); 3855 HandleMark hm(thread); 3856 (*unload_entry)(&main_vm); 3857 } 3858 } 3859 } 3860 3861 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3862 // Invokes JVM_OnLoad 3863 void Threads::create_vm_init_libraries() { 3864 extern struct JavaVM_ main_vm; 3865 AgentLibrary* agent; 3866 3867 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3868 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3869 3870 if (on_load_entry != NULL) { 3871 // Invoke the JVM_OnLoad function 3872 JavaThread* thread = JavaThread::current(); 3873 ThreadToNativeFromVM ttn(thread); 3874 HandleMark hm(thread); 3875 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3876 if (err != JNI_OK) { 3877 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3878 } 3879 } else { 3880 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3881 } 3882 } 3883 } 3884 3885 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3886 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3887 3888 JavaThread* java_thread = NULL; 3889 // Sequential search for now. Need to do better optimization later. 3890 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3891 oop tobj = thread->threadObj(); 3892 if (!thread->is_exiting() && 3893 tobj != NULL && 3894 java_tid == java_lang_Thread::thread_id(tobj)) { 3895 java_thread = thread; 3896 break; 3897 } 3898 } 3899 return java_thread; 3900 } 3901 3902 3903 // Last thread running calls java.lang.Shutdown.shutdown() 3904 void JavaThread::invoke_shutdown_hooks() { 3905 HandleMark hm(this); 3906 3907 // We could get here with a pending exception, if so clear it now. 3908 if (this->has_pending_exception()) { 3909 this->clear_pending_exception(); 3910 } 3911 3912 EXCEPTION_MARK; 3913 Klass* k = 3914 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3915 THREAD); 3916 if (k != NULL) { 3917 // SystemDictionary::resolve_or_null will return null if there was 3918 // an exception. If we cannot load the Shutdown class, just don't 3919 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3920 // and finalizers (if runFinalizersOnExit is set) won't be run. 3921 // Note that if a shutdown hook was registered or runFinalizersOnExit 3922 // was called, the Shutdown class would have already been loaded 3923 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3924 instanceKlassHandle shutdown_klass (THREAD, k); 3925 JavaValue result(T_VOID); 3926 JavaCalls::call_static(&result, 3927 shutdown_klass, 3928 vmSymbols::shutdown_method_name(), 3929 vmSymbols::void_method_signature(), 3930 THREAD); 3931 } 3932 CLEAR_PENDING_EXCEPTION; 3933 } 3934 3935 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3936 // the program falls off the end of main(). Another VM exit path is through 3937 // vm_exit() when the program calls System.exit() to return a value or when 3938 // there is a serious error in VM. The two shutdown paths are not exactly 3939 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3940 // and VM_Exit op at VM level. 3941 // 3942 // Shutdown sequence: 3943 // + Shutdown native memory tracking if it is on 3944 // + Wait until we are the last non-daemon thread to execute 3945 // <-- every thing is still working at this moment --> 3946 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3947 // shutdown hooks, run finalizers if finalization-on-exit 3948 // + Call before_exit(), prepare for VM exit 3949 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3950 // currently the only user of this mechanism is File.deleteOnExit()) 3951 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3952 // post thread end and vm death events to JVMTI, 3953 // stop signal thread 3954 // + Call JavaThread::exit(), it will: 3955 // > release JNI handle blocks, remove stack guard pages 3956 // > remove this thread from Threads list 3957 // <-- no more Java code from this thread after this point --> 3958 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3959 // the compiler threads at safepoint 3960 // <-- do not use anything that could get blocked by Safepoint --> 3961 // + Disable tracing at JNI/JVM barriers 3962 // + Set _vm_exited flag for threads that are still running native code 3963 // + Delete this thread 3964 // + Call exit_globals() 3965 // > deletes tty 3966 // > deletes PerfMemory resources 3967 // + Return to caller 3968 3969 bool Threads::destroy_vm() { 3970 JavaThread* thread = JavaThread::current(); 3971 3972 #ifdef ASSERT 3973 _vm_complete = false; 3974 #endif 3975 // Wait until we are the last non-daemon thread to execute 3976 { MutexLocker nu(Threads_lock); 3977 while (Threads::number_of_non_daemon_threads() > 1 ) 3978 // This wait should make safepoint checks, wait without a timeout, 3979 // and wait as a suspend-equivalent condition. 3980 // 3981 // Note: If the FlatProfiler is running and this thread is waiting 3982 // for another non-daemon thread to finish, then the FlatProfiler 3983 // is waiting for the external suspend request on this thread to 3984 // complete. wait_for_ext_suspend_completion() will eventually 3985 // timeout, but that takes time. Making this wait a suspend- 3986 // equivalent condition solves that timeout problem. 3987 // 3988 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3989 Mutex::_as_suspend_equivalent_flag); 3990 } 3991 3992 // Hang forever on exit if we are reporting an error. 3993 if (ShowMessageBoxOnError && is_error_reported()) { 3994 os::infinite_sleep(); 3995 } 3996 os::wait_for_keypress_at_exit(); 3997 3998 if (JDK_Version::is_jdk12x_version()) { 3999 // We are the last thread running, so check if finalizers should be run. 4000 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 4001 HandleMark rm(thread); 4002 Universe::run_finalizers_on_exit(); 4003 } else { 4004 // run Java level shutdown hooks 4005 thread->invoke_shutdown_hooks(); 4006 } 4007 4008 before_exit(thread); 4009 4010 thread->exit(true); 4011 4012 // Stop VM thread. 4013 { 4014 // 4945125 The vm thread comes to a safepoint during exit. 4015 // GC vm_operations can get caught at the safepoint, and the 4016 // heap is unparseable if they are caught. Grab the Heap_lock 4017 // to prevent this. The GC vm_operations will not be able to 4018 // queue until after the vm thread is dead. After this point, 4019 // we'll never emerge out of the safepoint before the VM exits. 4020 4021 MutexLocker ml(Heap_lock); 4022 4023 VMThread::wait_for_vm_thread_exit(); 4024 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4025 VMThread::destroy(); 4026 } 4027 4028 // clean up ideal graph printers 4029 #if defined(COMPILER2) && !defined(PRODUCT) 4030 IdealGraphPrinter::clean_up(); 4031 #endif 4032 4033 // Now, all Java threads are gone except daemon threads. Daemon threads 4034 // running Java code or in VM are stopped by the Safepoint. However, 4035 // daemon threads executing native code are still running. But they 4036 // will be stopped at native=>Java/VM barriers. Note that we can't 4037 // simply kill or suspend them, as it is inherently deadlock-prone. 4038 4039 #ifndef PRODUCT 4040 // disable function tracing at JNI/JVM barriers 4041 TraceJNICalls = false; 4042 TraceJVMCalls = false; 4043 TraceRuntimeCalls = false; 4044 #endif 4045 4046 VM_Exit::set_vm_exited(); 4047 4048 notify_vm_shutdown(); 4049 4050 delete thread; 4051 4052 // exit_globals() will delete tty 4053 exit_globals(); 4054 4055 return true; 4056 } 4057 4058 4059 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4060 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4061 return is_supported_jni_version(version); 4062 } 4063 4064 4065 jboolean Threads::is_supported_jni_version(jint version) { 4066 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4067 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4068 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4069 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4070 return JNI_FALSE; 4071 } 4072 4073 4074 void Threads::add(JavaThread* p, bool force_daemon) { 4075 // The threads lock must be owned at this point 4076 assert_locked_or_safepoint(Threads_lock); 4077 4078 // See the comment for this method in thread.hpp for its purpose and 4079 // why it is called here. 4080 p->initialize_queues(); 4081 p->set_next(_thread_list); 4082 _thread_list = p; 4083 _number_of_threads++; 4084 oop threadObj = p->threadObj(); 4085 bool daemon = true; 4086 // Bootstrapping problem: threadObj can be null for initial 4087 // JavaThread (or for threads attached via JNI) 4088 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4089 _number_of_non_daemon_threads++; 4090 daemon = false; 4091 } 4092 4093 ThreadService::add_thread(p, daemon); 4094 4095 // Possible GC point. 4096 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4097 } 4098 4099 void Threads::remove(JavaThread* p) { 4100 // Extra scope needed for Thread_lock, so we can check 4101 // that we do not remove thread without safepoint code notice 4102 { MutexLocker ml(Threads_lock); 4103 4104 assert(includes(p), "p must be present"); 4105 4106 JavaThread* current = _thread_list; 4107 JavaThread* prev = NULL; 4108 4109 while (current != p) { 4110 prev = current; 4111 current = current->next(); 4112 } 4113 4114 if (prev) { 4115 prev->set_next(current->next()); 4116 } else { 4117 _thread_list = p->next(); 4118 } 4119 _number_of_threads--; 4120 oop threadObj = p->threadObj(); 4121 bool daemon = true; 4122 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4123 _number_of_non_daemon_threads--; 4124 daemon = false; 4125 4126 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4127 // on destroy_vm will wake up. 4128 if (number_of_non_daemon_threads() == 1) 4129 Threads_lock->notify_all(); 4130 } 4131 ThreadService::remove_thread(p, daemon); 4132 4133 // Make sure that safepoint code disregard this thread. This is needed since 4134 // the thread might mess around with locks after this point. This can cause it 4135 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4136 // of this thread since it is removed from the queue. 4137 p->set_terminated_value(); 4138 } // unlock Threads_lock 4139 4140 // Since Events::log uses a lock, we grab it outside the Threads_lock 4141 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4142 } 4143 4144 // Threads_lock must be held when this is called (or must be called during a safepoint) 4145 bool Threads::includes(JavaThread* p) { 4146 assert(Threads_lock->is_locked(), "sanity check"); 4147 ALL_JAVA_THREADS(q) { 4148 if (q == p ) { 4149 return true; 4150 } 4151 } 4152 return false; 4153 } 4154 4155 // Operations on the Threads list for GC. These are not explicitly locked, 4156 // but the garbage collector must provide a safe context for them to run. 4157 // In particular, these things should never be called when the Threads_lock 4158 // is held by some other thread. (Note: the Safepoint abstraction also 4159 // uses the Threads_lock to gurantee this property. It also makes sure that 4160 // all threads gets blocked when exiting or starting). 4161 4162 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4163 ALL_JAVA_THREADS(p) { 4164 p->oops_do(f, cld_f, cf); 4165 } 4166 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4167 } 4168 4169 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4170 // Introduce a mechanism allowing parallel threads to claim threads as 4171 // root groups. Overhead should be small enough to use all the time, 4172 // even in sequential code. 4173 SharedHeap* sh = SharedHeap::heap(); 4174 // Cannot yet substitute active_workers for n_par_threads 4175 // because of G1CollectedHeap::verify() use of 4176 // SharedHeap::process_roots(). n_par_threads == 0 will 4177 // turn off parallelism in process_roots while active_workers 4178 // is being used for parallelism elsewhere. 4179 bool is_par = sh->n_par_threads() > 0; 4180 assert(!is_par || 4181 (SharedHeap::heap()->n_par_threads() == 4182 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4183 int cp = SharedHeap::heap()->strong_roots_parity(); 4184 ALL_JAVA_THREADS(p) { 4185 if (p->claim_oops_do(is_par, cp)) { 4186 p->oops_do(f, cld_f, cf); 4187 } 4188 } 4189 VMThread* vmt = VMThread::vm_thread(); 4190 if (vmt->claim_oops_do(is_par, cp)) { 4191 vmt->oops_do(f, cld_f, cf); 4192 } 4193 } 4194 4195 #if INCLUDE_ALL_GCS 4196 // Used by ParallelScavenge 4197 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4198 ALL_JAVA_THREADS(p) { 4199 q->enqueue(new ThreadRootsTask(p)); 4200 } 4201 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4202 } 4203 4204 // Used by Parallel Old 4205 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4206 ALL_JAVA_THREADS(p) { 4207 q->enqueue(new ThreadRootsMarkingTask(p)); 4208 } 4209 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4210 } 4211 #endif // INCLUDE_ALL_GCS 4212 4213 void Threads::nmethods_do(CodeBlobClosure* cf) { 4214 ALL_JAVA_THREADS(p) { 4215 p->nmethods_do(cf); 4216 } 4217 VMThread::vm_thread()->nmethods_do(cf); 4218 } 4219 4220 void Threads::metadata_do(void f(Metadata*)) { 4221 ALL_JAVA_THREADS(p) { 4222 p->metadata_do(f); 4223 } 4224 } 4225 4226 void Threads::gc_epilogue() { 4227 ALL_JAVA_THREADS(p) { 4228 p->gc_epilogue(); 4229 } 4230 } 4231 4232 void Threads::gc_prologue() { 4233 ALL_JAVA_THREADS(p) { 4234 p->gc_prologue(); 4235 } 4236 } 4237 4238 void Threads::deoptimized_wrt_marked_nmethods() { 4239 ALL_JAVA_THREADS(p) { 4240 p->deoptimized_wrt_marked_nmethods(); 4241 } 4242 } 4243 4244 4245 // Get count Java threads that are waiting to enter the specified monitor. 4246 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4247 address monitor, bool doLock) { 4248 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4249 "must grab Threads_lock or be at safepoint"); 4250 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4251 4252 int i = 0; 4253 { 4254 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4255 ALL_JAVA_THREADS(p) { 4256 if (p->is_Compiler_thread()) continue; 4257 4258 address pending = (address)p->current_pending_monitor(); 4259 if (pending == monitor) { // found a match 4260 if (i < count) result->append(p); // save the first count matches 4261 i++; 4262 } 4263 } 4264 } 4265 return result; 4266 } 4267 4268 4269 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4270 assert(doLock || 4271 Threads_lock->owned_by_self() || 4272 SafepointSynchronize::is_at_safepoint(), 4273 "must grab Threads_lock or be at safepoint"); 4274 4275 // NULL owner means not locked so we can skip the search 4276 if (owner == NULL) return NULL; 4277 4278 { 4279 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4280 ALL_JAVA_THREADS(p) { 4281 // first, see if owner is the address of a Java thread 4282 if (owner == (address)p) return p; 4283 } 4284 } 4285 // Cannot assert on lack of success here since this function may be 4286 // used by code that is trying to report useful problem information 4287 // like deadlock detection. 4288 if (UseHeavyMonitors) return NULL; 4289 4290 // 4291 // If we didn't find a matching Java thread and we didn't force use of 4292 // heavyweight monitors, then the owner is the stack address of the 4293 // Lock Word in the owning Java thread's stack. 4294 // 4295 JavaThread* the_owner = NULL; 4296 { 4297 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4298 ALL_JAVA_THREADS(q) { 4299 if (q->is_lock_owned(owner)) { 4300 the_owner = q; 4301 break; 4302 } 4303 } 4304 } 4305 // cannot assert on lack of success here; see above comment 4306 return the_owner; 4307 } 4308 4309 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4310 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4311 char buf[32]; 4312 st->print_cr("%s", os::local_time_string(buf, sizeof(buf))); 4313 4314 st->print_cr("Full thread dump %s (%s %s):", 4315 Abstract_VM_Version::vm_name(), 4316 Abstract_VM_Version::vm_release(), 4317 Abstract_VM_Version::vm_info_string() 4318 ); 4319 st->cr(); 4320 4321 #if INCLUDE_ALL_GCS 4322 // Dump concurrent locks 4323 ConcurrentLocksDump concurrent_locks; 4324 if (print_concurrent_locks) { 4325 concurrent_locks.dump_at_safepoint(); 4326 } 4327 #endif // INCLUDE_ALL_GCS 4328 4329 ALL_JAVA_THREADS(p) { 4330 ResourceMark rm; 4331 p->print_on(st); 4332 if (print_stacks) { 4333 if (internal_format) { 4334 p->trace_stack(); 4335 } else { 4336 p->print_stack_on(st); 4337 } 4338 } 4339 st->cr(); 4340 #if INCLUDE_ALL_GCS 4341 if (print_concurrent_locks) { 4342 concurrent_locks.print_locks_on(p, st); 4343 } 4344 #endif // INCLUDE_ALL_GCS 4345 } 4346 4347 VMThread::vm_thread()->print_on(st); 4348 st->cr(); 4349 Universe::heap()->print_gc_threads_on(st); 4350 WatcherThread* wt = WatcherThread::watcher_thread(); 4351 if (wt != NULL) { 4352 wt->print_on(st); 4353 st->cr(); 4354 } 4355 CompileBroker::print_compiler_threads_on(st); 4356 st->flush(); 4357 } 4358 4359 // Threads::print_on_error() is called by fatal error handler. It's possible 4360 // that VM is not at safepoint and/or current thread is inside signal handler. 4361 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4362 // memory (even in resource area), it might deadlock the error handler. 4363 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4364 bool found_current = false; 4365 st->print_cr("Java Threads: ( => current thread )"); 4366 ALL_JAVA_THREADS(thread) { 4367 bool is_current = (current == thread); 4368 found_current = found_current || is_current; 4369 4370 st->print("%s", is_current ? "=>" : " "); 4371 4372 st->print(PTR_FORMAT, thread); 4373 st->print(" "); 4374 thread->print_on_error(st, buf, buflen); 4375 st->cr(); 4376 } 4377 st->cr(); 4378 4379 st->print_cr("Other Threads:"); 4380 if (VMThread::vm_thread()) { 4381 bool is_current = (current == VMThread::vm_thread()); 4382 found_current = found_current || is_current; 4383 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4384 4385 st->print(PTR_FORMAT, VMThread::vm_thread()); 4386 st->print(" "); 4387 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4388 st->cr(); 4389 } 4390 WatcherThread* wt = WatcherThread::watcher_thread(); 4391 if (wt != NULL) { 4392 bool is_current = (current == wt); 4393 found_current = found_current || is_current; 4394 st->print("%s", is_current ? "=>" : " "); 4395 4396 st->print(PTR_FORMAT, wt); 4397 st->print(" "); 4398 wt->print_on_error(st, buf, buflen); 4399 st->cr(); 4400 } 4401 if (!found_current) { 4402 st->cr(); 4403 st->print("=>" PTR_FORMAT " (exited) ", current); 4404 current->print_on_error(st, buf, buflen); 4405 st->cr(); 4406 } 4407 } 4408 4409 // Internal SpinLock and Mutex 4410 // Based on ParkEvent 4411 4412 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4413 // 4414 // We employ SpinLocks _only for low-contention, fixed-length 4415 // short-duration critical sections where we're concerned 4416 // about native mutex_t or HotSpot Mutex:: latency. 4417 // The mux construct provides a spin-then-block mutual exclusion 4418 // mechanism. 4419 // 4420 // Testing has shown that contention on the ListLock guarding gFreeList 4421 // is common. If we implement ListLock as a simple SpinLock it's common 4422 // for the JVM to devolve to yielding with little progress. This is true 4423 // despite the fact that the critical sections protected by ListLock are 4424 // extremely short. 4425 // 4426 // TODO-FIXME: ListLock should be of type SpinLock. 4427 // We should make this a 1st-class type, integrated into the lock 4428 // hierarchy as leaf-locks. Critically, the SpinLock structure 4429 // should have sufficient padding to avoid false-sharing and excessive 4430 // cache-coherency traffic. 4431 4432 4433 typedef volatile int SpinLockT ; 4434 4435 void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4436 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4437 return ; // normal fast-path return 4438 } 4439 4440 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4441 TEVENT (SpinAcquire - ctx) ; 4442 int ctr = 0 ; 4443 int Yields = 0 ; 4444 for (;;) { 4445 while (*adr != 0) { 4446 ++ctr ; 4447 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4448 if (Yields > 5) { 4449 os::naked_short_sleep(1); 4450 } else { 4451 os::NakedYield() ; 4452 ++Yields ; 4453 } 4454 } else { 4455 SpinPause() ; 4456 } 4457 } 4458 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4459 } 4460 } 4461 4462 void Thread::SpinRelease (volatile int * adr) { 4463 assert (*adr != 0, "invariant") ; 4464 OrderAccess::fence() ; // guarantee at least release consistency. 4465 // Roach-motel semantics. 4466 // It's safe if subsequent LDs and STs float "up" into the critical section, 4467 // but prior LDs and STs within the critical section can't be allowed 4468 // to reorder or float past the ST that releases the lock. 4469 *adr = 0 ; 4470 } 4471 4472 // muxAcquire and muxRelease: 4473 // 4474 // * muxAcquire and muxRelease support a single-word lock-word construct. 4475 // The LSB of the word is set IFF the lock is held. 4476 // The remainder of the word points to the head of a singly-linked list 4477 // of threads blocked on the lock. 4478 // 4479 // * The current implementation of muxAcquire-muxRelease uses its own 4480 // dedicated Thread._MuxEvent instance. If we're interested in 4481 // minimizing the peak number of extant ParkEvent instances then 4482 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4483 // as certain invariants were satisfied. Specifically, care would need 4484 // to be taken with regards to consuming unpark() "permits". 4485 // A safe rule of thumb is that a thread would never call muxAcquire() 4486 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4487 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4488 // consume an unpark() permit intended for monitorenter, for instance. 4489 // One way around this would be to widen the restricted-range semaphore 4490 // implemented in park(). Another alternative would be to provide 4491 // multiple instances of the PlatformEvent() for each thread. One 4492 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4493 // 4494 // * Usage: 4495 // -- Only as leaf locks 4496 // -- for short-term locking only as muxAcquire does not perform 4497 // thread state transitions. 4498 // 4499 // Alternatives: 4500 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4501 // but with parking or spin-then-park instead of pure spinning. 4502 // * Use Taura-Oyama-Yonenzawa locks. 4503 // * It's possible to construct a 1-0 lock if we encode the lockword as 4504 // (List,LockByte). Acquire will CAS the full lockword while Release 4505 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4506 // acquiring threads use timers (ParkTimed) to detect and recover from 4507 // the stranding window. Thread/Node structures must be aligned on 256-byte 4508 // boundaries by using placement-new. 4509 // * Augment MCS with advisory back-link fields maintained with CAS(). 4510 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4511 // The validity of the backlinks must be ratified before we trust the value. 4512 // If the backlinks are invalid the exiting thread must back-track through the 4513 // the forward links, which are always trustworthy. 4514 // * Add a successor indication. The LockWord is currently encoded as 4515 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4516 // to provide the usual futile-wakeup optimization. 4517 // See RTStt for details. 4518 // * Consider schedctl.sc_nopreempt to cover the critical section. 4519 // 4520 4521 4522 typedef volatile intptr_t MutexT ; // Mux Lock-word 4523 enum MuxBits { LOCKBIT = 1 } ; 4524 4525 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4526 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4527 if (w == 0) return ; 4528 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4529 return ; 4530 } 4531 4532 TEVENT (muxAcquire - Contention) ; 4533 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4534 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4535 for (;;) { 4536 int its = (os::is_MP() ? 100 : 0) + 1 ; 4537 4538 // Optional spin phase: spin-then-park strategy 4539 while (--its >= 0) { 4540 w = *Lock ; 4541 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4542 return ; 4543 } 4544 } 4545 4546 Self->reset() ; 4547 Self->OnList = intptr_t(Lock) ; 4548 // The following fence() isn't _strictly necessary as the subsequent 4549 // CAS() both serializes execution and ratifies the fetched *Lock value. 4550 OrderAccess::fence(); 4551 for (;;) { 4552 w = *Lock ; 4553 if ((w & LOCKBIT) == 0) { 4554 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4555 Self->OnList = 0 ; // hygiene - allows stronger asserts 4556 return ; 4557 } 4558 continue ; // Interference -- *Lock changed -- Just retry 4559 } 4560 assert (w & LOCKBIT, "invariant") ; 4561 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4562 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4563 } 4564 4565 while (Self->OnList != 0) { 4566 Self->park() ; 4567 } 4568 } 4569 } 4570 4571 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4572 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4573 if (w == 0) return ; 4574 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4575 return ; 4576 } 4577 4578 TEVENT (muxAcquire - Contention) ; 4579 ParkEvent * ReleaseAfter = NULL ; 4580 if (ev == NULL) { 4581 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4582 } 4583 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4584 for (;;) { 4585 guarantee (ev->OnList == 0, "invariant") ; 4586 int its = (os::is_MP() ? 100 : 0) + 1 ; 4587 4588 // Optional spin phase: spin-then-park strategy 4589 while (--its >= 0) { 4590 w = *Lock ; 4591 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4592 if (ReleaseAfter != NULL) { 4593 ParkEvent::Release (ReleaseAfter) ; 4594 } 4595 return ; 4596 } 4597 } 4598 4599 ev->reset() ; 4600 ev->OnList = intptr_t(Lock) ; 4601 // The following fence() isn't _strictly necessary as the subsequent 4602 // CAS() both serializes execution and ratifies the fetched *Lock value. 4603 OrderAccess::fence(); 4604 for (;;) { 4605 w = *Lock ; 4606 if ((w & LOCKBIT) == 0) { 4607 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4608 ev->OnList = 0 ; 4609 // We call ::Release while holding the outer lock, thus 4610 // artificially lengthening the critical section. 4611 // Consider deferring the ::Release() until the subsequent unlock(), 4612 // after we've dropped the outer lock. 4613 if (ReleaseAfter != NULL) { 4614 ParkEvent::Release (ReleaseAfter) ; 4615 } 4616 return ; 4617 } 4618 continue ; // Interference -- *Lock changed -- Just retry 4619 } 4620 assert (w & LOCKBIT, "invariant") ; 4621 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4622 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4623 } 4624 4625 while (ev->OnList != 0) { 4626 ev->park() ; 4627 } 4628 } 4629 } 4630 4631 // Release() must extract a successor from the list and then wake that thread. 4632 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4633 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4634 // Release() would : 4635 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4636 // (B) Extract a successor from the private list "in-hand" 4637 // (C) attempt to CAS() the residual back into *Lock over null. 4638 // If there were any newly arrived threads and the CAS() would fail. 4639 // In that case Release() would detach the RATs, re-merge the list in-hand 4640 // with the RATs and repeat as needed. Alternately, Release() might 4641 // detach and extract a successor, but then pass the residual list to the wakee. 4642 // The wakee would be responsible for reattaching and remerging before it 4643 // competed for the lock. 4644 // 4645 // Both "pop" and DMR are immune from ABA corruption -- there can be 4646 // multiple concurrent pushers, but only one popper or detacher. 4647 // This implementation pops from the head of the list. This is unfair, 4648 // but tends to provide excellent throughput as hot threads remain hot. 4649 // (We wake recently run threads first). 4650 4651 void Thread::muxRelease (volatile intptr_t * Lock) { 4652 for (;;) { 4653 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4654 assert (w & LOCKBIT, "invariant") ; 4655 if (w == LOCKBIT) return ; 4656 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4657 assert (List != NULL, "invariant") ; 4658 assert (List->OnList == intptr_t(Lock), "invariant") ; 4659 ParkEvent * nxt = List->ListNext ; 4660 4661 // The following CAS() releases the lock and pops the head element. 4662 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4663 continue ; 4664 } 4665 List->OnList = 0 ; 4666 OrderAccess::fence() ; 4667 List->unpark () ; 4668 return ; 4669 } 4670 } 4671 4672 4673 void Threads::verify() { 4674 ALL_JAVA_THREADS(p) { 4675 p->verify(); 4676 } 4677 VMThread* thread = VMThread::vm_thread(); 4678 if (thread != NULL) thread->verify(); 4679 }