1 /* 2 * Copyright (c) 1997, 2013, 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/osThread.hpp" 62 #include "runtime/safepoint.hpp" 63 #include "runtime/sharedRuntime.hpp" 64 #include "runtime/statSampler.hpp" 65 #include "runtime/stubRoutines.hpp" 66 #include "runtime/task.hpp" 67 #include "runtime/thread.inline.hpp" 68 #include "runtime/threadCritical.hpp" 69 #include "runtime/threadLocalStorage.hpp" 70 #include "runtime/vframe.hpp" 71 #include "runtime/vframeArray.hpp" 72 #include "runtime/vframe_hp.hpp" 73 #include "runtime/vmThread.hpp" 74 #include "runtime/vm_operations.hpp" 75 #include "services/attachListener.hpp" 76 #include "services/management.hpp" 77 #include "services/memTracker.hpp" 78 #include "services/threadService.hpp" 79 #include "trace/tracing.hpp" 80 #include "trace/traceMacros.hpp" 81 #include "utilities/defaultStream.hpp" 82 #include "utilities/dtrace.hpp" 83 #include "utilities/events.hpp" 84 #include "utilities/preserveException.hpp" 85 #include "utilities/macros.hpp" 86 #ifdef TARGET_OS_FAMILY_linux 87 # include "os_linux.inline.hpp" 88 #endif 89 #ifdef TARGET_OS_FAMILY_solaris 90 # include "os_solaris.inline.hpp" 91 #endif 92 #ifdef TARGET_OS_FAMILY_windows 93 # include "os_windows.inline.hpp" 94 #endif 95 #ifdef TARGET_OS_FAMILY_bsd 96 # include "os_bsd.inline.hpp" 97 #endif 98 #if INCLUDE_ALL_GCS 99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 101 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 102 #endif // INCLUDE_ALL_GCS 103 #ifdef COMPILER1 104 #include "c1/c1_Compiler.hpp" 105 #endif 106 #ifdef COMPILER2 107 #include "opto/c2compiler.hpp" 108 #include "opto/idealGraphPrinter.hpp" 109 #endif 110 111 #ifdef DTRACE_ENABLED 112 113 // Only bother with this argument setup if dtrace is available 114 115 #ifndef USDT2 116 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 117 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 118 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 119 intptr_t, intptr_t, bool); 120 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 121 intptr_t, intptr_t, bool); 122 123 #define DTRACE_THREAD_PROBE(probe, javathread) \ 124 { \ 125 ResourceMark rm(this); \ 126 int len = 0; \ 127 const char* name = (javathread)->get_thread_name(); \ 128 len = strlen(name); \ 129 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 130 name, len, \ 131 java_lang_Thread::thread_id((javathread)->threadObj()), \ 132 (javathread)->osthread()->thread_id(), \ 133 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 134 } 135 136 #else /* USDT2 */ 137 138 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START 139 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP 140 141 #define DTRACE_THREAD_PROBE(probe, javathread) \ 142 { \ 143 ResourceMark rm(this); \ 144 int len = 0; \ 145 const char* name = (javathread)->get_thread_name(); \ 146 len = strlen(name); \ 147 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 148 (char *) name, len, \ 149 java_lang_Thread::thread_id((javathread)->threadObj()), \ 150 (uintptr_t) (javathread)->osthread()->thread_id(), \ 151 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 152 } 153 154 #endif /* USDT2 */ 155 156 #else // ndef DTRACE_ENABLED 157 158 #define DTRACE_THREAD_PROBE(probe, javathread) 159 160 #endif // ndef DTRACE_ENABLED 161 162 163 // Class hierarchy 164 // - Thread 165 // - VMThread 166 // - WatcherThread 167 // - ConcurrentMarkSweepThread 168 // - JavaThread 169 // - CompilerThread 170 171 // ======= Thread ======== 172 // Support for forcing alignment of thread objects for biased locking 173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 174 if (UseBiasedLocking) { 175 const int alignment = markOopDesc::biased_lock_alignment; 176 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 178 : AllocateHeap(aligned_size, flags, CURRENT_PC, 179 AllocFailStrategy::RETURN_NULL); 180 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 183 "JavaThread alignment code overflowed allocated storage"); 184 if (TraceBiasedLocking) { 185 if (aligned_addr != real_malloc_addr) 186 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 187 real_malloc_addr, aligned_addr); 188 } 189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 190 return aligned_addr; 191 } else { 192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 194 } 195 } 196 197 void Thread::operator delete(void* p) { 198 if (UseBiasedLocking) { 199 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 200 FreeHeap(real_malloc_addr, mtThread); 201 } else { 202 FreeHeap(p, mtThread); 203 } 204 } 205 206 207 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 208 // JavaThread 209 210 211 Thread::Thread() { 212 // stack and get_thread 213 set_stack_base(NULL); 214 set_stack_size(0); 215 set_self_raw_id(0); 216 set_lgrp_id(-1); 217 218 // allocated data structures 219 set_osthread(NULL); 220 set_resource_area(new (mtThread)ResourceArea()); 221 DEBUG_ONLY(_current_resource_mark = NULL;) 222 set_handle_area(new (mtThread) HandleArea(NULL)); 223 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 224 set_active_handles(NULL); 225 set_free_handle_block(NULL); 226 set_last_handle_mark(NULL); 227 228 // This initial value ==> never claimed. 229 _oops_do_parity = 0; 230 231 // the handle mark links itself to last_handle_mark 232 new HandleMark(this); 233 234 // plain initialization 235 debug_only(_owned_locks = NULL;) 236 debug_only(_allow_allocation_count = 0;) 237 NOT_PRODUCT(_allow_safepoint_count = 0;) 238 NOT_PRODUCT(_skip_gcalot = false;) 239 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;) 240 _jvmti_env_iteration_count = 0; 241 set_allocated_bytes(0); 242 _vm_operation_started_count = 0; 243 _vm_operation_completed_count = 0; 244 _current_pending_monitor = NULL; 245 _current_pending_monitor_is_from_java = true; 246 _current_waiting_monitor = NULL; 247 _num_nested_signal = 0; 248 omFreeList = NULL ; 249 omFreeCount = 0 ; 250 omFreeProvision = 32 ; 251 omInUseList = NULL ; 252 omInUseCount = 0 ; 253 254 #ifdef ASSERT 255 _visited_for_critical_count = false; 256 #endif 257 258 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 259 _suspend_flags = 0; 260 261 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 262 _hashStateX = os::random() ; 263 _hashStateY = 842502087 ; 264 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 265 _hashStateW = 273326509 ; 266 267 _OnTrap = 0 ; 268 _schedctl = NULL ; 269 _Stalled = 0 ; 270 _TypeTag = 0x2BAD ; 271 272 // Many of the following fields are effectively final - immutable 273 // Note that nascent threads can't use the Native Monitor-Mutex 274 // construct until the _MutexEvent is initialized ... 275 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 276 // we might instead use a stack of ParkEvents that we could provision on-demand. 277 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 278 // and ::Release() 279 _ParkEvent = ParkEvent::Allocate (this) ; 280 _SleepEvent = ParkEvent::Allocate (this) ; 281 _MutexEvent = ParkEvent::Allocate (this) ; 282 _MuxEvent = ParkEvent::Allocate (this) ; 283 284 #ifdef CHECK_UNHANDLED_OOPS 285 if (CheckUnhandledOops) { 286 _unhandled_oops = new UnhandledOops(this); 287 } 288 #endif // CHECK_UNHANDLED_OOPS 289 #ifdef ASSERT 290 if (UseBiasedLocking) { 291 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 292 assert(this == _real_malloc_address || 293 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 294 "bug in forced alignment of thread objects"); 295 } 296 #endif /* ASSERT */ 297 } 298 299 void Thread::initialize_thread_local_storage() { 300 // Note: Make sure this method only calls 301 // non-blocking operations. Otherwise, it might not work 302 // with the thread-startup/safepoint interaction. 303 304 // During Java thread startup, safepoint code should allow this 305 // method to complete because it may need to allocate memory to 306 // store information for the new thread. 307 308 // initialize structure dependent on thread local storage 309 ThreadLocalStorage::set_thread(this); 310 } 311 312 void Thread::record_stack_base_and_size() { 313 set_stack_base(os::current_stack_base()); 314 set_stack_size(os::current_stack_size()); 315 // CR 7190089: on Solaris, primordial thread's stack is adjusted 316 // in initialize_thread(). Without the adjustment, stack size is 317 // incorrect if stack is set to unlimited (ulimit -s unlimited). 318 // So far, only Solaris has real implementation of initialize_thread(). 319 // 320 // set up any platform-specific state. 321 os::initialize_thread(this); 322 323 #if INCLUDE_NMT 324 // record thread's native stack, stack grows downward 325 address stack_low_addr = stack_base() - stack_size(); 326 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 327 CURRENT_PC); 328 #endif // INCLUDE_NMT 329 } 330 331 332 Thread::~Thread() { 333 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 334 ObjectSynchronizer::omFlush (this) ; 335 336 // stack_base can be NULL if the thread is never started or exited before 337 // record_stack_base_and_size called. Although, we would like to ensure 338 // that all started threads do call record_stack_base_and_size(), there is 339 // not proper way to enforce that. 340 #if INCLUDE_NMT 341 if (_stack_base != NULL) { 342 address low_stack_addr = stack_base() - stack_size(); 343 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); 344 #ifdef ASSERT 345 set_stack_base(NULL); 346 #endif 347 } 348 #endif // INCLUDE_NMT 349 350 // deallocate data structures 351 delete resource_area(); 352 // since the handle marks are using the handle area, we have to deallocated the root 353 // handle mark before deallocating the thread's handle area, 354 assert(last_handle_mark() != NULL, "check we have an element"); 355 delete last_handle_mark(); 356 assert(last_handle_mark() == NULL, "check we have reached the end"); 357 358 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 359 // We NULL out the fields for good hygiene. 360 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 361 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 362 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 363 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 364 365 delete handle_area(); 366 delete metadata_handles(); 367 368 // osthread() can be NULL, if creation of thread failed. 369 if (osthread() != NULL) os::free_thread(osthread()); 370 371 delete _SR_lock; 372 373 // clear thread local storage if the Thread is deleting itself 374 if (this == Thread::current()) { 375 ThreadLocalStorage::set_thread(NULL); 376 } else { 377 // In the case where we're not the current thread, invalidate all the 378 // caches in case some code tries to get the current thread or the 379 // thread that was destroyed, and gets stale information. 380 ThreadLocalStorage::invalidate_all(); 381 } 382 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 383 } 384 385 // NOTE: dummy function for assertion purpose. 386 void Thread::run() { 387 ShouldNotReachHere(); 388 } 389 390 #ifdef ASSERT 391 // Private method to check for dangling thread pointer 392 void check_for_dangling_thread_pointer(Thread *thread) { 393 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 394 "possibility of dangling Thread pointer"); 395 } 396 #endif 397 398 399 #ifndef PRODUCT 400 // Tracing method for basic thread operations 401 void Thread::trace(const char* msg, const Thread* const thread) { 402 if (!TraceThreadEvents) return; 403 ResourceMark rm; 404 ThreadCritical tc; 405 const char *name = "non-Java thread"; 406 int prio = -1; 407 if (thread->is_Java_thread() 408 && !thread->is_Compiler_thread()) { 409 // The Threads_lock must be held to get information about 410 // this thread but may not be in some situations when 411 // tracing thread events. 412 bool release_Threads_lock = false; 413 if (!Threads_lock->owned_by_self()) { 414 Threads_lock->lock(); 415 release_Threads_lock = true; 416 } 417 JavaThread* jt = (JavaThread *)thread; 418 name = (char *)jt->get_thread_name(); 419 oop thread_oop = jt->threadObj(); 420 if (thread_oop != NULL) { 421 prio = java_lang_Thread::priority(thread_oop); 422 } 423 if (release_Threads_lock) { 424 Threads_lock->unlock(); 425 } 426 } 427 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 428 } 429 #endif 430 431 432 ThreadPriority Thread::get_priority(const Thread* const thread) { 433 trace("get priority", thread); 434 ThreadPriority priority; 435 // Can return an error! 436 (void)os::get_priority(thread, priority); 437 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 438 return priority; 439 } 440 441 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 442 trace("set priority", thread); 443 debug_only(check_for_dangling_thread_pointer(thread);) 444 // Can return an error! 445 (void)os::set_priority(thread, priority); 446 } 447 448 449 void Thread::start(Thread* thread) { 450 trace("start", thread); 451 // Start is different from resume in that its safety is guaranteed by context or 452 // being called from a Java method synchronized on the Thread object. 453 if (!DisableStartThread) { 454 if (thread->is_Java_thread()) { 455 // Initialize the thread state to RUNNABLE before starting this thread. 456 // Can not set it after the thread started because we do not know the 457 // exact thread state at that time. It could be in MONITOR_WAIT or 458 // in SLEEPING or some other state. 459 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 460 java_lang_Thread::RUNNABLE); 461 } 462 os::start_thread(thread); 463 } 464 } 465 466 // Enqueue a VM_Operation to do the job for us - sometime later 467 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 468 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 469 VMThread::execute(vm_stop); 470 } 471 472 473 // 474 // Check if an external suspend request has completed (or has been 475 // cancelled). Returns true if the thread is externally suspended and 476 // false otherwise. 477 // 478 // The bits parameter returns information about the code path through 479 // the routine. Useful for debugging: 480 // 481 // set in is_ext_suspend_completed(): 482 // 0x00000001 - routine was entered 483 // 0x00000010 - routine return false at end 484 // 0x00000100 - thread exited (return false) 485 // 0x00000200 - suspend request cancelled (return false) 486 // 0x00000400 - thread suspended (return true) 487 // 0x00001000 - thread is in a suspend equivalent state (return true) 488 // 0x00002000 - thread is native and walkable (return true) 489 // 0x00004000 - thread is native_trans and walkable (needed retry) 490 // 491 // set in wait_for_ext_suspend_completion(): 492 // 0x00010000 - routine was entered 493 // 0x00020000 - suspend request cancelled before loop (return false) 494 // 0x00040000 - thread suspended before loop (return true) 495 // 0x00080000 - suspend request cancelled in loop (return false) 496 // 0x00100000 - thread suspended in loop (return true) 497 // 0x00200000 - suspend not completed during retry loop (return false) 498 // 499 500 // Helper class for tracing suspend wait debug bits. 501 // 502 // 0x00000100 indicates that the target thread exited before it could 503 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 504 // 0x00080000 each indicate a cancelled suspend request so they don't 505 // count as wait failures either. 506 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 507 508 class TraceSuspendDebugBits : public StackObj { 509 private: 510 JavaThread * jt; 511 bool is_wait; 512 bool called_by_wait; // meaningful when !is_wait 513 uint32_t * bits; 514 515 public: 516 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 517 uint32_t *_bits) { 518 jt = _jt; 519 is_wait = _is_wait; 520 called_by_wait = _called_by_wait; 521 bits = _bits; 522 } 523 524 ~TraceSuspendDebugBits() { 525 if (!is_wait) { 526 #if 1 527 // By default, don't trace bits for is_ext_suspend_completed() calls. 528 // That trace is very chatty. 529 return; 530 #else 531 if (!called_by_wait) { 532 // If tracing for is_ext_suspend_completed() is enabled, then only 533 // trace calls to it from wait_for_ext_suspend_completion() 534 return; 535 } 536 #endif 537 } 538 539 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 540 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 541 MutexLocker ml(Threads_lock); // needed for get_thread_name() 542 ResourceMark rm; 543 544 tty->print_cr( 545 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 546 jt->get_thread_name(), *bits); 547 548 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 549 } 550 } 551 } 552 }; 553 #undef DEBUG_FALSE_BITS 554 555 556 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 557 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 558 559 bool did_trans_retry = false; // only do thread_in_native_trans retry once 560 bool do_trans_retry; // flag to force the retry 561 562 *bits |= 0x00000001; 563 564 do { 565 do_trans_retry = false; 566 567 if (is_exiting()) { 568 // Thread is in the process of exiting. This is always checked 569 // first to reduce the risk of dereferencing a freed JavaThread. 570 *bits |= 0x00000100; 571 return false; 572 } 573 574 if (!is_external_suspend()) { 575 // Suspend request is cancelled. This is always checked before 576 // is_ext_suspended() to reduce the risk of a rogue resume 577 // confusing the thread that made the suspend request. 578 *bits |= 0x00000200; 579 return false; 580 } 581 582 if (is_ext_suspended()) { 583 // thread is suspended 584 *bits |= 0x00000400; 585 return true; 586 } 587 588 // Now that we no longer do hard suspends of threads running 589 // native code, the target thread can be changing thread state 590 // while we are in this routine: 591 // 592 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 593 // 594 // We save a copy of the thread state as observed at this moment 595 // and make our decision about suspend completeness based on the 596 // copy. This closes the race where the thread state is seen as 597 // _thread_in_native_trans in the if-thread_blocked check, but is 598 // seen as _thread_blocked in if-thread_in_native_trans check. 599 JavaThreadState save_state = thread_state(); 600 601 if (save_state == _thread_blocked && is_suspend_equivalent()) { 602 // If the thread's state is _thread_blocked and this blocking 603 // condition is known to be equivalent to a suspend, then we can 604 // consider the thread to be externally suspended. This means that 605 // the code that sets _thread_blocked has been modified to do 606 // self-suspension if the blocking condition releases. We also 607 // used to check for CONDVAR_WAIT here, but that is now covered by 608 // the _thread_blocked with self-suspension check. 609 // 610 // Return true since we wouldn't be here unless there was still an 611 // external suspend request. 612 *bits |= 0x00001000; 613 return true; 614 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 615 // Threads running native code will self-suspend on native==>VM/Java 616 // transitions. If its stack is walkable (should always be the case 617 // unless this function is called before the actual java_suspend() 618 // call), then the wait is done. 619 *bits |= 0x00002000; 620 return true; 621 } else if (!called_by_wait && !did_trans_retry && 622 save_state == _thread_in_native_trans && 623 frame_anchor()->walkable()) { 624 // The thread is transitioning from thread_in_native to another 625 // thread state. check_safepoint_and_suspend_for_native_trans() 626 // will force the thread to self-suspend. If it hasn't gotten 627 // there yet we may have caught the thread in-between the native 628 // code check above and the self-suspend. Lucky us. If we were 629 // called by wait_for_ext_suspend_completion(), then it 630 // will be doing the retries so we don't have to. 631 // 632 // Since we use the saved thread state in the if-statement above, 633 // there is a chance that the thread has already transitioned to 634 // _thread_blocked by the time we get here. In that case, we will 635 // make a single unnecessary pass through the logic below. This 636 // doesn't hurt anything since we still do the trans retry. 637 638 *bits |= 0x00004000; 639 640 // Once the thread leaves thread_in_native_trans for another 641 // thread state, we break out of this retry loop. We shouldn't 642 // need this flag to prevent us from getting back here, but 643 // sometimes paranoia is good. 644 did_trans_retry = true; 645 646 // We wait for the thread to transition to a more usable state. 647 for (int i = 1; i <= SuspendRetryCount; i++) { 648 // We used to do an "os::yield_all(i)" call here with the intention 649 // that yielding would increase on each retry. However, the parameter 650 // is ignored on Linux which means the yield didn't scale up. Waiting 651 // on the SR_lock below provides a much more predictable scale up for 652 // the delay. It also provides a simple/direct point to check for any 653 // safepoint requests from the VMThread 654 655 // temporarily drops SR_lock while doing wait with safepoint check 656 // (if we're a JavaThread - the WatcherThread can also call this) 657 // and increase delay with each retry 658 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 659 660 // check the actual thread state instead of what we saved above 661 if (thread_state() != _thread_in_native_trans) { 662 // the thread has transitioned to another thread state so 663 // try all the checks (except this one) one more time. 664 do_trans_retry = true; 665 break; 666 } 667 } // end retry loop 668 669 670 } 671 } while (do_trans_retry); 672 673 *bits |= 0x00000010; 674 return false; 675 } 676 677 // 678 // Wait for an external suspend request to complete (or be cancelled). 679 // Returns true if the thread is externally suspended and false otherwise. 680 // 681 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 682 uint32_t *bits) { 683 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 684 false /* !called_by_wait */, bits); 685 686 // local flag copies to minimize SR_lock hold time 687 bool is_suspended; 688 bool pending; 689 uint32_t reset_bits; 690 691 // set a marker so is_ext_suspend_completed() knows we are the caller 692 *bits |= 0x00010000; 693 694 // We use reset_bits to reinitialize the bits value at the top of 695 // each retry loop. This allows the caller to make use of any 696 // unused bits for their own marking purposes. 697 reset_bits = *bits; 698 699 { 700 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 701 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 702 delay, bits); 703 pending = is_external_suspend(); 704 } 705 // must release SR_lock to allow suspension to complete 706 707 if (!pending) { 708 // A cancelled suspend request is the only false return from 709 // is_ext_suspend_completed() that keeps us from entering the 710 // retry loop. 711 *bits |= 0x00020000; 712 return false; 713 } 714 715 if (is_suspended) { 716 *bits |= 0x00040000; 717 return true; 718 } 719 720 for (int i = 1; i <= retries; i++) { 721 *bits = reset_bits; // reinit to only track last retry 722 723 // We used to do an "os::yield_all(i)" call here with the intention 724 // that yielding would increase on each retry. However, the parameter 725 // is ignored on Linux which means the yield didn't scale up. Waiting 726 // on the SR_lock below provides a much more predictable scale up for 727 // the delay. It also provides a simple/direct point to check for any 728 // safepoint requests from the VMThread 729 730 { 731 MutexLocker ml(SR_lock()); 732 // wait with safepoint check (if we're a JavaThread - the WatcherThread 733 // can also call this) and increase delay with each retry 734 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 735 736 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 737 delay, bits); 738 739 // It is possible for the external suspend request to be cancelled 740 // (by a resume) before the actual suspend operation is completed. 741 // Refresh our local copy to see if we still need to wait. 742 pending = is_external_suspend(); 743 } 744 745 if (!pending) { 746 // A cancelled suspend request is the only false return from 747 // is_ext_suspend_completed() that keeps us from staying in the 748 // retry loop. 749 *bits |= 0x00080000; 750 return false; 751 } 752 753 if (is_suspended) { 754 *bits |= 0x00100000; 755 return true; 756 } 757 } // end retry loop 758 759 // thread did not suspend after all our retries 760 *bits |= 0x00200000; 761 return false; 762 } 763 764 #ifndef PRODUCT 765 void JavaThread::record_jump(address target, address instr, const char* file, int line) { 766 767 // This should not need to be atomic as the only way for simultaneous 768 // updates is via interrupts. Even then this should be rare or non-existant 769 // and we don't care that much anyway. 770 771 int index = _jmp_ring_index; 772 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 773 _jmp_ring[index]._target = (intptr_t) target; 774 _jmp_ring[index]._instruction = (intptr_t) instr; 775 _jmp_ring[index]._file = file; 776 _jmp_ring[index]._line = line; 777 } 778 #endif /* PRODUCT */ 779 780 // Called by flat profiler 781 // Callers have already called wait_for_ext_suspend_completion 782 // The assertion for that is currently too complex to put here: 783 bool JavaThread::profile_last_Java_frame(frame* _fr) { 784 bool gotframe = false; 785 // self suspension saves needed state. 786 if (has_last_Java_frame() && _anchor.walkable()) { 787 *_fr = pd_last_frame(); 788 gotframe = true; 789 } 790 return gotframe; 791 } 792 793 void Thread::interrupt(Thread* thread) { 794 trace("interrupt", thread); 795 debug_only(check_for_dangling_thread_pointer(thread);) 796 os::interrupt(thread); 797 } 798 799 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 800 trace("is_interrupted", thread); 801 debug_only(check_for_dangling_thread_pointer(thread);) 802 // Note: If clear_interrupted==false, this simply fetches and 803 // returns the value of the field osthread()->interrupted(). 804 return os::is_interrupted(thread, clear_interrupted); 805 } 806 807 808 // GC Support 809 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 810 jint thread_parity = _oops_do_parity; 811 if (thread_parity != strong_roots_parity) { 812 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 813 if (res == thread_parity) { 814 return true; 815 } else { 816 guarantee(res == strong_roots_parity, "Or else what?"); 817 assert(SharedHeap::heap()->workers()->active_workers() > 0, 818 "Should only fail when parallel."); 819 return false; 820 } 821 } 822 assert(SharedHeap::heap()->workers()->active_workers() > 0, 823 "Should only fail when parallel."); 824 return false; 825 } 826 827 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 828 active_handles()->oops_do(f); 829 // Do oop for ThreadShadow 830 f->do_oop((oop*)&_pending_exception); 831 handle_area()->oops_do(f); 832 } 833 834 void Thread::nmethods_do(CodeBlobClosure* cf) { 835 // no nmethods in a generic thread... 836 } 837 838 void Thread::metadata_do(void f(Metadata*)) { 839 if (metadata_handles() != NULL) { 840 for (int i = 0; i< metadata_handles()->length(); i++) { 841 f(metadata_handles()->at(i)); 842 } 843 } 844 } 845 846 void Thread::print_on(outputStream* st) const { 847 // get_priority assumes osthread initialized 848 if (osthread() != NULL) { 849 int os_prio; 850 if (os::get_native_priority(this, &os_prio) == OS_OK) { 851 st->print("os_prio=%d ", os_prio); 852 } 853 st->print("tid=" INTPTR_FORMAT " ", this); 854 osthread()->print_on(st); 855 } 856 debug_only(if (WizardMode) print_owned_locks_on(st);) 857 } 858 859 // Thread::print_on_error() is called by fatal error handler. Don't use 860 // any lock or allocate memory. 861 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 862 if (is_VM_thread()) st->print("VMThread"); 863 else if (is_Compiler_thread()) st->print("CompilerThread"); 864 else if (is_Java_thread()) st->print("JavaThread"); 865 else if (is_GC_task_thread()) st->print("GCTaskThread"); 866 else if (is_Watcher_thread()) st->print("WatcherThread"); 867 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 868 else st->print("Thread"); 869 870 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 871 _stack_base - _stack_size, _stack_base); 872 873 if (osthread()) { 874 st->print(" [id=%d]", osthread()->thread_id()); 875 } 876 } 877 878 #ifdef ASSERT 879 void Thread::print_owned_locks_on(outputStream* st) const { 880 Monitor *cur = _owned_locks; 881 if (cur == NULL) { 882 st->print(" (no locks) "); 883 } else { 884 st->print_cr(" Locks owned:"); 885 while(cur) { 886 cur->print_on(st); 887 cur = cur->next(); 888 } 889 } 890 } 891 892 static int ref_use_count = 0; 893 894 bool Thread::owns_locks_but_compiled_lock() const { 895 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 896 if (cur != Compile_lock) return true; 897 } 898 return false; 899 } 900 901 902 #endif 903 904 #ifndef PRODUCT 905 906 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 907 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 908 // no threads which allow_vm_block's are held 909 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 910 // Check if current thread is allowed to block at a safepoint 911 if (!(_allow_safepoint_count == 0)) 912 fatal("Possible safepoint reached by thread that does not allow it"); 913 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 914 fatal("LEAF method calling lock?"); 915 } 916 917 #ifdef ASSERT 918 if (potential_vm_operation && is_Java_thread() 919 && !Universe::is_bootstrapping()) { 920 // Make sure we do not hold any locks that the VM thread also uses. 921 // This could potentially lead to deadlocks 922 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 923 // Threads_lock is special, since the safepoint synchronization will not start before this is 924 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 925 // since it is used to transfer control between JavaThreads and the VMThread 926 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first! 927 if ( (cur->allow_vm_block() && 928 cur != Threads_lock && 929 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation 930 cur != VMOperationRequest_lock && 931 cur != VMOperationQueue_lock) || 932 cur->rank() == Mutex::special) { 933 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 934 } 935 } 936 } 937 938 if (GCALotAtAllSafepoints) { 939 // We could enter a safepoint here and thus have a gc 940 InterfaceSupport::check_gc_alot(); 941 } 942 #endif 943 } 944 #endif 945 946 bool Thread::is_in_stack(address adr) const { 947 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 948 address end = os::current_stack_pointer(); 949 // Allow non Java threads to call this without stack_base 950 if (_stack_base == NULL) return true; 951 if (stack_base() >= adr && adr >= end) return true; 952 953 return false; 954 } 955 956 957 bool Thread::is_in_usable_stack(address adr) const { 958 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 959 size_t usable_stack_size = _stack_size - stack_guard_size; 960 961 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 962 } 963 964 965 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 966 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 967 // used for compilation in the future. If that change is made, the need for these methods 968 // should be revisited, and they should be removed if possible. 969 970 bool Thread::is_lock_owned(address adr) const { 971 return on_local_stack(adr); 972 } 973 974 bool Thread::set_as_starting_thread() { 975 // NOTE: this must be called inside the main thread. 976 return os::create_main_thread((JavaThread*)this); 977 } 978 979 static void initialize_class(Symbol* class_name, TRAPS) { 980 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 981 InstanceKlass::cast(klass)->initialize(CHECK); 982 } 983 984 985 // Creates the initial ThreadGroup 986 static Handle create_initial_thread_group(TRAPS) { 987 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 988 instanceKlassHandle klass (THREAD, k); 989 990 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 991 { 992 JavaValue result(T_VOID); 993 JavaCalls::call_special(&result, 994 system_instance, 995 klass, 996 vmSymbols::object_initializer_name(), 997 vmSymbols::void_method_signature(), 998 CHECK_NH); 999 } 1000 Universe::set_system_thread_group(system_instance()); 1001 1002 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 1003 { 1004 JavaValue result(T_VOID); 1005 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 1006 JavaCalls::call_special(&result, 1007 main_instance, 1008 klass, 1009 vmSymbols::object_initializer_name(), 1010 vmSymbols::threadgroup_string_void_signature(), 1011 system_instance, 1012 string, 1013 CHECK_NH); 1014 } 1015 return main_instance; 1016 } 1017 1018 // Creates the initial Thread 1019 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1020 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1021 instanceKlassHandle klass (THREAD, k); 1022 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1023 1024 java_lang_Thread::set_thread(thread_oop(), thread); 1025 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1026 thread->set_threadObj(thread_oop()); 1027 1028 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1029 1030 JavaValue result(T_VOID); 1031 JavaCalls::call_special(&result, thread_oop, 1032 klass, 1033 vmSymbols::object_initializer_name(), 1034 vmSymbols::threadgroup_string_void_signature(), 1035 thread_group, 1036 string, 1037 CHECK_NULL); 1038 return thread_oop(); 1039 } 1040 1041 static void call_initializeSystemClass(TRAPS) { 1042 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1043 instanceKlassHandle klass (THREAD, k); 1044 1045 JavaValue result(T_VOID); 1046 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1047 vmSymbols::void_method_signature(), CHECK); 1048 } 1049 1050 char java_runtime_name[128] = ""; 1051 char java_runtime_version[128] = ""; 1052 1053 // extract the JRE name from sun.misc.Version.java_runtime_name 1054 static const char* get_java_runtime_name(TRAPS) { 1055 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1056 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1057 fieldDescriptor fd; 1058 bool found = k != NULL && 1059 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1060 vmSymbols::string_signature(), &fd); 1061 if (found) { 1062 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1063 if (name_oop == NULL) 1064 return NULL; 1065 const char* name = java_lang_String::as_utf8_string(name_oop, 1066 java_runtime_name, 1067 sizeof(java_runtime_name)); 1068 return name; 1069 } else { 1070 return NULL; 1071 } 1072 } 1073 1074 // extract the JRE version from sun.misc.Version.java_runtime_version 1075 static const char* get_java_runtime_version(TRAPS) { 1076 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1077 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1078 fieldDescriptor fd; 1079 bool found = k != NULL && 1080 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1081 vmSymbols::string_signature(), &fd); 1082 if (found) { 1083 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1084 if (name_oop == NULL) 1085 return NULL; 1086 const char* name = java_lang_String::as_utf8_string(name_oop, 1087 java_runtime_version, 1088 sizeof(java_runtime_version)); 1089 return name; 1090 } else { 1091 return NULL; 1092 } 1093 } 1094 1095 // General purpose hook into Java code, run once when the VM is initialized. 1096 // The Java library method itself may be changed independently from the VM. 1097 static void call_postVMInitHook(TRAPS) { 1098 Klass* k = SystemDictionary::PostVMInitHook_klass(); 1099 instanceKlassHandle klass (THREAD, k); 1100 if (klass.not_null()) { 1101 JavaValue result(T_VOID); 1102 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1103 vmSymbols::void_method_signature(), 1104 CHECK); 1105 } 1106 } 1107 1108 static void reset_vm_info_property(TRAPS) { 1109 // the vm info string 1110 ResourceMark rm(THREAD); 1111 const char *vm_info = VM_Version::vm_info_string(); 1112 1113 // java.lang.System class 1114 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1115 instanceKlassHandle klass (THREAD, k); 1116 1117 // setProperty arguments 1118 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1119 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1120 1121 // return value 1122 JavaValue r(T_OBJECT); 1123 1124 // public static String setProperty(String key, String value); 1125 JavaCalls::call_static(&r, 1126 klass, 1127 vmSymbols::setProperty_name(), 1128 vmSymbols::string_string_string_signature(), 1129 key_str, 1130 value_str, 1131 CHECK); 1132 } 1133 1134 1135 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1136 assert(thread_group.not_null(), "thread group should be specified"); 1137 assert(threadObj() == NULL, "should only create Java thread object once"); 1138 1139 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1140 instanceKlassHandle klass (THREAD, k); 1141 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1142 1143 java_lang_Thread::set_thread(thread_oop(), this); 1144 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1145 set_threadObj(thread_oop()); 1146 1147 JavaValue result(T_VOID); 1148 if (thread_name != NULL) { 1149 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1150 // Thread gets assigned specified name and null target 1151 JavaCalls::call_special(&result, 1152 thread_oop, 1153 klass, 1154 vmSymbols::object_initializer_name(), 1155 vmSymbols::threadgroup_string_void_signature(), 1156 thread_group, // Argument 1 1157 name, // Argument 2 1158 THREAD); 1159 } else { 1160 // Thread gets assigned name "Thread-nnn" and null target 1161 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1162 JavaCalls::call_special(&result, 1163 thread_oop, 1164 klass, 1165 vmSymbols::object_initializer_name(), 1166 vmSymbols::threadgroup_runnable_void_signature(), 1167 thread_group, // Argument 1 1168 Handle(), // Argument 2 1169 THREAD); 1170 } 1171 1172 1173 if (daemon) { 1174 java_lang_Thread::set_daemon(thread_oop()); 1175 } 1176 1177 if (HAS_PENDING_EXCEPTION) { 1178 return; 1179 } 1180 1181 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1182 Handle threadObj(this, this->threadObj()); 1183 1184 JavaCalls::call_special(&result, 1185 thread_group, 1186 group, 1187 vmSymbols::add_method_name(), 1188 vmSymbols::thread_void_signature(), 1189 threadObj, // Arg 1 1190 THREAD); 1191 1192 1193 } 1194 1195 // NamedThread -- non-JavaThread subclasses with multiple 1196 // uniquely named instances should derive from this. 1197 NamedThread::NamedThread() : Thread() { 1198 _name = NULL; 1199 _processed_thread = NULL; 1200 } 1201 1202 NamedThread::~NamedThread() { 1203 if (_name != NULL) { 1204 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1205 _name = NULL; 1206 } 1207 } 1208 1209 void NamedThread::set_name(const char* format, ...) { 1210 guarantee(_name == NULL, "Only get to set name once."); 1211 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1212 guarantee(_name != NULL, "alloc failure"); 1213 va_list ap; 1214 va_start(ap, format); 1215 jio_vsnprintf(_name, max_name_len, format, ap); 1216 va_end(ap); 1217 } 1218 1219 // ======= WatcherThread ======== 1220 1221 // The watcher thread exists to simulate timer interrupts. It should 1222 // be replaced by an abstraction over whatever native support for 1223 // timer interrupts exists on the platform. 1224 1225 WatcherThread* WatcherThread::_watcher_thread = NULL; 1226 bool WatcherThread::_startable = false; 1227 volatile bool WatcherThread::_should_terminate = false; 1228 1229 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1230 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1231 if (os::create_thread(this, os::watcher_thread)) { 1232 _watcher_thread = this; 1233 1234 // Set the watcher thread to the highest OS priority which should not be 1235 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1236 // is created. The only normal thread using this priority is the reference 1237 // handler thread, which runs for very short intervals only. 1238 // If the VMThread's priority is not lower than the WatcherThread profiling 1239 // will be inaccurate. 1240 os::set_priority(this, MaxPriority); 1241 if (!DisableStartThread) { 1242 os::start_thread(this); 1243 } 1244 } 1245 } 1246 1247 int WatcherThread::sleep() const { 1248 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1249 1250 // remaining will be zero if there are no tasks, 1251 // causing the WatcherThread to sleep until a task is 1252 // enrolled 1253 int remaining = PeriodicTask::time_to_wait(); 1254 int time_slept = 0; 1255 1256 // we expect this to timeout - we only ever get unparked when 1257 // we should terminate or when a new task has been enrolled 1258 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1259 1260 jlong time_before_loop = os::javaTimeNanos(); 1261 1262 for (;;) { 1263 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1264 jlong now = os::javaTimeNanos(); 1265 1266 if (remaining == 0) { 1267 // if we didn't have any tasks we could have waited for a long time 1268 // consider the time_slept zero and reset time_before_loop 1269 time_slept = 0; 1270 time_before_loop = now; 1271 } else { 1272 // need to recalulate since we might have new tasks in _tasks 1273 time_slept = (int) ((now - time_before_loop) / 1000000); 1274 } 1275 1276 // Change to task list or spurious wakeup of some kind 1277 if (timedout || _should_terminate) { 1278 break; 1279 } 1280 1281 remaining = PeriodicTask::time_to_wait(); 1282 if (remaining == 0) { 1283 // Last task was just disenrolled so loop around and wait until 1284 // another task gets enrolled 1285 continue; 1286 } 1287 1288 remaining -= time_slept; 1289 if (remaining <= 0) 1290 break; 1291 } 1292 1293 return time_slept; 1294 } 1295 1296 void WatcherThread::run() { 1297 assert(this == watcher_thread(), "just checking"); 1298 1299 this->record_stack_base_and_size(); 1300 this->initialize_thread_local_storage(); 1301 this->set_active_handles(JNIHandleBlock::allocate_block()); 1302 while(!_should_terminate) { 1303 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1304 assert(watcher_thread() == this, "thread consistency check"); 1305 1306 // Calculate how long it'll be until the next PeriodicTask work 1307 // should be done, and sleep that amount of time. 1308 int time_waited = sleep(); 1309 1310 if (is_error_reported()) { 1311 // A fatal error has happened, the error handler(VMError::report_and_die) 1312 // should abort JVM after creating an error log file. However in some 1313 // rare cases, the error handler itself might deadlock. Here we try to 1314 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1315 // 1316 // This code is in WatcherThread because WatcherThread wakes up 1317 // periodically so the fatal error handler doesn't need to do anything; 1318 // also because the WatcherThread is less likely to crash than other 1319 // threads. 1320 1321 for (;;) { 1322 if (!ShowMessageBoxOnError 1323 && (OnError == NULL || OnError[0] == '\0') 1324 && Arguments::abort_hook() == NULL) { 1325 os::sleep(this, 2 * 60 * 1000, false); 1326 fdStream err(defaultStream::output_fd()); 1327 err.print_raw_cr("# [ timer expired, abort... ]"); 1328 // skip atexit/vm_exit/vm_abort hooks 1329 os::die(); 1330 } 1331 1332 // Wake up 5 seconds later, the fatal handler may reset OnError or 1333 // ShowMessageBoxOnError when it is ready to abort. 1334 os::sleep(this, 5 * 1000, false); 1335 } 1336 } 1337 1338 PeriodicTask::real_time_tick(time_waited); 1339 } 1340 1341 // Signal that it is terminated 1342 { 1343 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1344 _watcher_thread = NULL; 1345 Terminator_lock->notify(); 1346 } 1347 1348 // Thread destructor usually does this.. 1349 ThreadLocalStorage::set_thread(NULL); 1350 } 1351 1352 void WatcherThread::start() { 1353 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1354 1355 if (watcher_thread() == NULL && _startable) { 1356 _should_terminate = false; 1357 // Create the single instance of WatcherThread 1358 new WatcherThread(); 1359 } 1360 } 1361 1362 void WatcherThread::make_startable() { 1363 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1364 _startable = true; 1365 } 1366 1367 void WatcherThread::stop() { 1368 { 1369 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1370 _should_terminate = true; 1371 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1372 1373 WatcherThread* watcher = watcher_thread(); 1374 if (watcher != NULL) 1375 watcher->unpark(); 1376 } 1377 1378 // it is ok to take late safepoints here, if needed 1379 MutexLocker mu(Terminator_lock); 1380 1381 while(watcher_thread() != NULL) { 1382 // This wait should make safepoint checks, wait without a timeout, 1383 // and wait as a suspend-equivalent condition. 1384 // 1385 // Note: If the FlatProfiler is running, then this thread is waiting 1386 // for the WatcherThread to terminate and the WatcherThread, via the 1387 // FlatProfiler task, is waiting for the external suspend request on 1388 // this thread to complete. wait_for_ext_suspend_completion() will 1389 // eventually timeout, but that takes time. Making this wait a 1390 // suspend-equivalent condition solves that timeout problem. 1391 // 1392 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1393 Mutex::_as_suspend_equivalent_flag); 1394 } 1395 } 1396 1397 void WatcherThread::unpark() { 1398 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1399 PeriodicTask_lock->notify(); 1400 } 1401 1402 void WatcherThread::print_on(outputStream* st) const { 1403 st->print("\"%s\" ", name()); 1404 Thread::print_on(st); 1405 st->cr(); 1406 } 1407 1408 // ======= JavaThread ======== 1409 1410 // A JavaThread is a normal Java thread 1411 1412 void JavaThread::initialize() { 1413 // Initialize fields 1414 1415 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1416 set_claimed_par_id(-1); 1417 1418 set_saved_exception_pc(NULL); 1419 set_threadObj(NULL); 1420 _anchor.clear(); 1421 set_entry_point(NULL); 1422 set_jni_functions(jni_functions()); 1423 set_callee_target(NULL); 1424 set_vm_result(NULL); 1425 set_vm_result_2(NULL); 1426 set_vframe_array_head(NULL); 1427 set_vframe_array_last(NULL); 1428 set_deferred_locals(NULL); 1429 set_deopt_mark(NULL); 1430 set_deopt_nmethod(NULL); 1431 clear_must_deopt_id(); 1432 set_monitor_chunks(NULL); 1433 set_next(NULL); 1434 set_thread_state(_thread_new); 1435 #if INCLUDE_NMT 1436 set_recorder(NULL); 1437 #endif 1438 _terminated = _not_terminated; 1439 _privileged_stack_top = NULL; 1440 _array_for_gc = NULL; 1441 _suspend_equivalent = false; 1442 _in_deopt_handler = 0; 1443 _doing_unsafe_access = false; 1444 _stack_guard_state = stack_guard_unused; 1445 _exception_oop = NULL; 1446 _exception_pc = 0; 1447 _exception_handler_pc = 0; 1448 _is_method_handle_return = 0; 1449 _jvmti_thread_state= NULL; 1450 _should_post_on_exceptions_flag = JNI_FALSE; 1451 _jvmti_get_loaded_classes_closure = NULL; 1452 _interp_only_mode = 0; 1453 _special_runtime_exit_condition = _no_async_condition; 1454 _pending_async_exception = NULL; 1455 _is_compiling = false; 1456 _thread_stat = NULL; 1457 _thread_stat = new ThreadStatistics(); 1458 _blocked_on_compilation = false; 1459 _jni_active_critical = 0; 1460 _do_not_unlock_if_synchronized = false; 1461 _cached_monitor_info = NULL; 1462 _parker = Parker::Allocate(this) ; 1463 1464 #ifndef PRODUCT 1465 _jmp_ring_index = 0; 1466 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1467 record_jump(NULL, NULL, NULL, 0); 1468 } 1469 #endif /* PRODUCT */ 1470 1471 set_thread_profiler(NULL); 1472 if (FlatProfiler::is_active()) { 1473 // This is where we would decide to either give each thread it's own profiler 1474 // or use one global one from FlatProfiler, 1475 // or up to some count of the number of profiled threads, etc. 1476 ThreadProfiler* pp = new ThreadProfiler(); 1477 pp->engage(); 1478 set_thread_profiler(pp); 1479 } 1480 1481 // Setup safepoint state info for this thread 1482 ThreadSafepointState::create(this); 1483 1484 debug_only(_java_call_counter = 0); 1485 1486 // JVMTI PopFrame support 1487 _popframe_condition = popframe_inactive; 1488 _popframe_preserved_args = NULL; 1489 _popframe_preserved_args_size = 0; 1490 1491 pd_initialize(); 1492 } 1493 1494 #if INCLUDE_ALL_GCS 1495 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1496 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1497 #endif // INCLUDE_ALL_GCS 1498 1499 JavaThread::JavaThread(bool is_attaching_via_jni) : 1500 Thread() 1501 #if INCLUDE_ALL_GCS 1502 , _satb_mark_queue(&_satb_mark_queue_set), 1503 _dirty_card_queue(&_dirty_card_queue_set) 1504 #endif // INCLUDE_ALL_GCS 1505 { 1506 initialize(); 1507 if (is_attaching_via_jni) { 1508 _jni_attach_state = _attaching_via_jni; 1509 } else { 1510 _jni_attach_state = _not_attaching_via_jni; 1511 } 1512 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1513 _safepoint_visible = false; 1514 } 1515 1516 bool JavaThread::reguard_stack(address cur_sp) { 1517 if (_stack_guard_state != stack_guard_yellow_disabled) { 1518 return true; // Stack already guarded or guard pages not needed. 1519 } 1520 1521 if (register_stack_overflow()) { 1522 // For those architectures which have separate register and 1523 // memory stacks, we must check the register stack to see if 1524 // it has overflowed. 1525 return false; 1526 } 1527 1528 // Java code never executes within the yellow zone: the latter is only 1529 // there to provoke an exception during stack banging. If java code 1530 // is executing there, either StackShadowPages should be larger, or 1531 // some exception code in c1, c2 or the interpreter isn't unwinding 1532 // when it should. 1533 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1534 1535 enable_stack_yellow_zone(); 1536 return true; 1537 } 1538 1539 bool JavaThread::reguard_stack(void) { 1540 return reguard_stack(os::current_stack_pointer()); 1541 } 1542 1543 1544 void JavaThread::block_if_vm_exited() { 1545 if (_terminated == _vm_exited) { 1546 // _vm_exited is set at safepoint, and Threads_lock is never released 1547 // we will block here forever 1548 Threads_lock->lock_without_safepoint_check(); 1549 ShouldNotReachHere(); 1550 } 1551 } 1552 1553 1554 // Remove this ifdef when C1 is ported to the compiler interface. 1555 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1556 1557 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1558 Thread() 1559 #if INCLUDE_ALL_GCS 1560 , _satb_mark_queue(&_satb_mark_queue_set), 1561 _dirty_card_queue(&_dirty_card_queue_set) 1562 #endif // INCLUDE_ALL_GCS 1563 { 1564 if (TraceThreadEvents) { 1565 tty->print_cr("creating thread %p", this); 1566 } 1567 initialize(); 1568 _jni_attach_state = _not_attaching_via_jni; 1569 set_entry_point(entry_point); 1570 // Create the native thread itself. 1571 // %note runtime_23 1572 os::ThreadType thr_type = os::java_thread; 1573 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1574 os::java_thread; 1575 os::create_thread(this, thr_type, stack_sz); 1576 _safepoint_visible = false; 1577 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1578 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1579 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1580 // the exception consists of creating the exception object & initializing it, initialization 1581 // will leave the VM via a JavaCall and then all locks must be unlocked). 1582 // 1583 // The thread is still suspended when we reach here. Thread must be explicit started 1584 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1585 // by calling Threads:add. The reason why this is not done here, is because the thread 1586 // object must be fully initialized (take a look at JVM_Start) 1587 } 1588 1589 JavaThread::~JavaThread() { 1590 if (TraceThreadEvents) { 1591 tty->print_cr("terminate thread %p", this); 1592 } 1593 1594 // By now, this thread should already be invisible to safepoint, 1595 // and its per-thread recorder also collected. 1596 assert(!is_safepoint_visible(), "wrong state"); 1597 #if INCLUDE_NMT 1598 assert(get_recorder() == NULL, "Already collected"); 1599 #endif // INCLUDE_NMT 1600 1601 // JSR166 -- return the parker to the free list 1602 Parker::Release(_parker); 1603 _parker = NULL ; 1604 1605 // Free any remaining previous UnrollBlock 1606 vframeArray* old_array = vframe_array_last(); 1607 1608 if (old_array != NULL) { 1609 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1610 old_array->set_unroll_block(NULL); 1611 delete old_info; 1612 delete old_array; 1613 } 1614 1615 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1616 if (deferred != NULL) { 1617 // This can only happen if thread is destroyed before deoptimization occurs. 1618 assert(deferred->length() != 0, "empty array!"); 1619 do { 1620 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1621 deferred->remove_at(0); 1622 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1623 delete dlv; 1624 } while (deferred->length() != 0); 1625 delete deferred; 1626 } 1627 1628 // All Java related clean up happens in exit 1629 ThreadSafepointState::destroy(this); 1630 if (_thread_profiler != NULL) delete _thread_profiler; 1631 if (_thread_stat != NULL) delete _thread_stat; 1632 } 1633 1634 1635 // The first routine called by a new Java thread 1636 void JavaThread::run() { 1637 // initialize thread-local alloc buffer related fields 1638 this->initialize_tlab(); 1639 1640 // used to test validitity of stack trace backs 1641 this->record_base_of_stack_pointer(); 1642 1643 // Record real stack base and size. 1644 this->record_stack_base_and_size(); 1645 1646 // Initialize thread local storage; set before calling MutexLocker 1647 this->initialize_thread_local_storage(); 1648 1649 this->create_stack_guard_pages(); 1650 1651 this->cache_global_variables(); 1652 1653 // Thread is now sufficient initialized to be handled by the safepoint code as being 1654 // in the VM. Change thread state from _thread_new to _thread_in_vm 1655 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1656 1657 assert(JavaThread::current() == this, "sanity check"); 1658 assert(!Thread::current()->owns_locks(), "sanity check"); 1659 1660 DTRACE_THREAD_PROBE(start, this); 1661 1662 // This operation might block. We call that after all safepoint checks for a new thread has 1663 // been completed. 1664 this->set_active_handles(JNIHandleBlock::allocate_block()); 1665 1666 if (JvmtiExport::should_post_thread_life()) { 1667 JvmtiExport::post_thread_start(this); 1668 } 1669 1670 EventThreadStart event; 1671 if (event.should_commit()) { 1672 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1673 event.commit(); 1674 } 1675 1676 // We call another function to do the rest so we are sure that the stack addresses used 1677 // from there will be lower than the stack base just computed 1678 thread_main_inner(); 1679 1680 // Note, thread is no longer valid at this point! 1681 } 1682 1683 1684 void JavaThread::thread_main_inner() { 1685 assert(JavaThread::current() == this, "sanity check"); 1686 assert(this->threadObj() != NULL, "just checking"); 1687 1688 // Execute thread entry point unless this thread has a pending exception 1689 // or has been stopped before starting. 1690 // Note: Due to JVM_StopThread we can have pending exceptions already! 1691 if (!this->has_pending_exception() && 1692 !java_lang_Thread::is_stillborn(this->threadObj())) { 1693 { 1694 ResourceMark rm(this); 1695 this->set_native_thread_name(this->get_thread_name()); 1696 } 1697 HandleMark hm(this); 1698 this->entry_point()(this, this); 1699 } 1700 1701 DTRACE_THREAD_PROBE(stop, this); 1702 1703 this->exit(false); 1704 delete this; 1705 } 1706 1707 1708 static void ensure_join(JavaThread* thread) { 1709 // We do not need to grap the Threads_lock, since we are operating on ourself. 1710 Handle threadObj(thread, thread->threadObj()); 1711 assert(threadObj.not_null(), "java thread object must exist"); 1712 ObjectLocker lock(threadObj, thread); 1713 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1714 thread->clear_pending_exception(); 1715 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1716 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1717 // Clear the native thread instance - this makes isAlive return false and allows the join() 1718 // to complete once we've done the notify_all below 1719 java_lang_Thread::set_thread(threadObj(), NULL); 1720 lock.notify_all(thread); 1721 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1722 thread->clear_pending_exception(); 1723 } 1724 1725 1726 // For any new cleanup additions, please check to see if they need to be applied to 1727 // cleanup_failed_attach_current_thread as well. 1728 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1729 assert(this == JavaThread::current(), "thread consistency check"); 1730 1731 HandleMark hm(this); 1732 Handle uncaught_exception(this, this->pending_exception()); 1733 this->clear_pending_exception(); 1734 Handle threadObj(this, this->threadObj()); 1735 assert(threadObj.not_null(), "Java thread object should be created"); 1736 1737 if (get_thread_profiler() != NULL) { 1738 get_thread_profiler()->disengage(); 1739 ResourceMark rm; 1740 get_thread_profiler()->print(get_thread_name()); 1741 } 1742 1743 1744 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1745 { 1746 EXCEPTION_MARK; 1747 1748 CLEAR_PENDING_EXCEPTION; 1749 } 1750 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1751 // has to be fixed by a runtime query method 1752 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1753 // JSR-166: change call from from ThreadGroup.uncaughtException to 1754 // java.lang.Thread.dispatchUncaughtException 1755 if (uncaught_exception.not_null()) { 1756 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1757 { 1758 EXCEPTION_MARK; 1759 // Check if the method Thread.dispatchUncaughtException() exists. If so 1760 // call it. Otherwise we have an older library without the JSR-166 changes, 1761 // so call ThreadGroup.uncaughtException() 1762 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1763 CallInfo callinfo; 1764 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1765 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1766 vmSymbols::dispatchUncaughtException_name(), 1767 vmSymbols::throwable_void_signature(), 1768 KlassHandle(), false, false, THREAD); 1769 CLEAR_PENDING_EXCEPTION; 1770 methodHandle method = callinfo.selected_method(); 1771 if (method.not_null()) { 1772 JavaValue result(T_VOID); 1773 JavaCalls::call_virtual(&result, 1774 threadObj, thread_klass, 1775 vmSymbols::dispatchUncaughtException_name(), 1776 vmSymbols::throwable_void_signature(), 1777 uncaught_exception, 1778 THREAD); 1779 } else { 1780 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1781 JavaValue result(T_VOID); 1782 JavaCalls::call_virtual(&result, 1783 group, thread_group, 1784 vmSymbols::uncaughtException_name(), 1785 vmSymbols::thread_throwable_void_signature(), 1786 threadObj, // Arg 1 1787 uncaught_exception, // Arg 2 1788 THREAD); 1789 } 1790 if (HAS_PENDING_EXCEPTION) { 1791 ResourceMark rm(this); 1792 jio_fprintf(defaultStream::error_stream(), 1793 "\nException: %s thrown from the UncaughtExceptionHandler" 1794 " in thread \"%s\"\n", 1795 pending_exception()->klass()->external_name(), 1796 get_thread_name()); 1797 CLEAR_PENDING_EXCEPTION; 1798 } 1799 } 1800 } 1801 1802 // Called before the java thread exit since we want to read info 1803 // from java_lang_Thread object 1804 EventThreadEnd event; 1805 if (event.should_commit()) { 1806 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1807 event.commit(); 1808 } 1809 1810 // Call after last event on thread 1811 EVENT_THREAD_EXIT(this); 1812 1813 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1814 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1815 // is deprecated anyhow. 1816 { int count = 3; 1817 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1818 EXCEPTION_MARK; 1819 JavaValue result(T_VOID); 1820 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1821 JavaCalls::call_virtual(&result, 1822 threadObj, thread_klass, 1823 vmSymbols::exit_method_name(), 1824 vmSymbols::void_method_signature(), 1825 THREAD); 1826 CLEAR_PENDING_EXCEPTION; 1827 } 1828 } 1829 1830 // notify JVMTI 1831 if (JvmtiExport::should_post_thread_life()) { 1832 JvmtiExport::post_thread_end(this); 1833 } 1834 1835 // We have notified the agents that we are exiting, before we go on, 1836 // we must check for a pending external suspend request and honor it 1837 // in order to not surprise the thread that made the suspend request. 1838 while (true) { 1839 { 1840 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1841 if (!is_external_suspend()) { 1842 set_terminated(_thread_exiting); 1843 ThreadService::current_thread_exiting(this); 1844 break; 1845 } 1846 // Implied else: 1847 // Things get a little tricky here. We have a pending external 1848 // suspend request, but we are holding the SR_lock so we 1849 // can't just self-suspend. So we temporarily drop the lock 1850 // and then self-suspend. 1851 } 1852 1853 ThreadBlockInVM tbivm(this); 1854 java_suspend_self(); 1855 1856 // We're done with this suspend request, but we have to loop around 1857 // and check again. Eventually we will get SR_lock without a pending 1858 // external suspend request and will be able to mark ourselves as 1859 // exiting. 1860 } 1861 // no more external suspends are allowed at this point 1862 } else { 1863 // before_exit() has already posted JVMTI THREAD_END events 1864 } 1865 1866 // Notify waiters on thread object. This has to be done after exit() is called 1867 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1868 // group should have the destroyed bit set before waiters are notified). 1869 ensure_join(this); 1870 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1871 1872 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1873 // held by this thread must be released. A detach operation must only 1874 // get here if there are no Java frames on the stack. Therefore, any 1875 // owned monitors at this point MUST be JNI-acquired monitors which are 1876 // pre-inflated and in the monitor cache. 1877 // 1878 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1879 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1880 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1881 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1882 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1883 } 1884 1885 // These things needs to be done while we are still a Java Thread. Make sure that thread 1886 // is in a consistent state, in case GC happens 1887 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1888 1889 if (active_handles() != NULL) { 1890 JNIHandleBlock* block = active_handles(); 1891 set_active_handles(NULL); 1892 JNIHandleBlock::release_block(block); 1893 } 1894 1895 if (free_handle_block() != NULL) { 1896 JNIHandleBlock* block = free_handle_block(); 1897 set_free_handle_block(NULL); 1898 JNIHandleBlock::release_block(block); 1899 } 1900 1901 // These have to be removed while this is still a valid thread. 1902 remove_stack_guard_pages(); 1903 1904 if (UseTLAB) { 1905 tlab().make_parsable(true); // retire TLAB 1906 } 1907 1908 if (JvmtiEnv::environments_might_exist()) { 1909 JvmtiExport::cleanup_thread(this); 1910 } 1911 1912 // We must flush any deferred card marks before removing a thread from 1913 // the list of active threads. 1914 Universe::heap()->flush_deferred_store_barrier(this); 1915 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1916 1917 #if INCLUDE_ALL_GCS 1918 // We must flush the G1-related buffers before removing a thread 1919 // from the list of active threads. We must do this after any deferred 1920 // card marks have been flushed (above) so that any entries that are 1921 // added to the thread's dirty card queue as a result are not lost. 1922 if (UseG1GC) { 1923 flush_barrier_queues(); 1924 } 1925 #endif // INCLUDE_ALL_GCS 1926 1927 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1928 Threads::remove(this); 1929 } 1930 1931 #if INCLUDE_ALL_GCS 1932 // Flush G1-related queues. 1933 void JavaThread::flush_barrier_queues() { 1934 satb_mark_queue().flush(); 1935 dirty_card_queue().flush(); 1936 } 1937 1938 void JavaThread::initialize_queues() { 1939 assert(!SafepointSynchronize::is_at_safepoint(), 1940 "we should not be at a safepoint"); 1941 1942 ObjPtrQueue& satb_queue = satb_mark_queue(); 1943 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1944 // The SATB queue should have been constructed with its active 1945 // field set to false. 1946 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1947 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1948 // If we are creating the thread during a marking cycle, we should 1949 // set the active field of the SATB queue to true. 1950 if (satb_queue_set.is_active()) { 1951 satb_queue.set_active(true); 1952 } 1953 1954 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1955 // The dirty card queue should have been constructed with its 1956 // active field set to true. 1957 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1958 } 1959 #endif // INCLUDE_ALL_GCS 1960 1961 void JavaThread::cleanup_failed_attach_current_thread() { 1962 if (get_thread_profiler() != NULL) { 1963 get_thread_profiler()->disengage(); 1964 ResourceMark rm; 1965 get_thread_profiler()->print(get_thread_name()); 1966 } 1967 1968 if (active_handles() != NULL) { 1969 JNIHandleBlock* block = active_handles(); 1970 set_active_handles(NULL); 1971 JNIHandleBlock::release_block(block); 1972 } 1973 1974 if (free_handle_block() != NULL) { 1975 JNIHandleBlock* block = free_handle_block(); 1976 set_free_handle_block(NULL); 1977 JNIHandleBlock::release_block(block); 1978 } 1979 1980 // These have to be removed while this is still a valid thread. 1981 remove_stack_guard_pages(); 1982 1983 if (UseTLAB) { 1984 tlab().make_parsable(true); // retire TLAB, if any 1985 } 1986 1987 #if INCLUDE_ALL_GCS 1988 if (UseG1GC) { 1989 flush_barrier_queues(); 1990 } 1991 #endif // INCLUDE_ALL_GCS 1992 1993 Threads::remove(this); 1994 delete this; 1995 } 1996 1997 1998 1999 2000 JavaThread* JavaThread::active() { 2001 Thread* thread = ThreadLocalStorage::thread(); 2002 assert(thread != NULL, "just checking"); 2003 if (thread->is_Java_thread()) { 2004 return (JavaThread*) thread; 2005 } else { 2006 assert(thread->is_VM_thread(), "this must be a vm thread"); 2007 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2008 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2009 assert(ret->is_Java_thread(), "must be a Java thread"); 2010 return ret; 2011 } 2012 } 2013 2014 bool JavaThread::is_lock_owned(address adr) const { 2015 if (Thread::is_lock_owned(adr)) return true; 2016 2017 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2018 if (chunk->contains(adr)) return true; 2019 } 2020 2021 return false; 2022 } 2023 2024 2025 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2026 chunk->set_next(monitor_chunks()); 2027 set_monitor_chunks(chunk); 2028 } 2029 2030 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2031 guarantee(monitor_chunks() != NULL, "must be non empty"); 2032 if (monitor_chunks() == chunk) { 2033 set_monitor_chunks(chunk->next()); 2034 } else { 2035 MonitorChunk* prev = monitor_chunks(); 2036 while (prev->next() != chunk) prev = prev->next(); 2037 prev->set_next(chunk->next()); 2038 } 2039 } 2040 2041 // JVM support. 2042 2043 // Note: this function shouldn't block if it's called in 2044 // _thread_in_native_trans state (such as from 2045 // check_special_condition_for_native_trans()). 2046 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2047 2048 if (has_last_Java_frame() && has_async_condition()) { 2049 // If we are at a polling page safepoint (not a poll return) 2050 // then we must defer async exception because live registers 2051 // will be clobbered by the exception path. Poll return is 2052 // ok because the call we a returning from already collides 2053 // with exception handling registers and so there is no issue. 2054 // (The exception handling path kills call result registers but 2055 // this is ok since the exception kills the result anyway). 2056 2057 if (is_at_poll_safepoint()) { 2058 // if the code we are returning to has deoptimized we must defer 2059 // the exception otherwise live registers get clobbered on the 2060 // exception path before deoptimization is able to retrieve them. 2061 // 2062 RegisterMap map(this, false); 2063 frame caller_fr = last_frame().sender(&map); 2064 assert(caller_fr.is_compiled_frame(), "what?"); 2065 if (caller_fr.is_deoptimized_frame()) { 2066 if (TraceExceptions) { 2067 ResourceMark rm; 2068 tty->print_cr("deferred async exception at compiled safepoint"); 2069 } 2070 return; 2071 } 2072 } 2073 } 2074 2075 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2076 if (condition == _no_async_condition) { 2077 // Conditions have changed since has_special_runtime_exit_condition() 2078 // was called: 2079 // - if we were here only because of an external suspend request, 2080 // then that was taken care of above (or cancelled) so we are done 2081 // - if we were here because of another async request, then it has 2082 // been cleared between the has_special_runtime_exit_condition() 2083 // and now so again we are done 2084 return; 2085 } 2086 2087 // Check for pending async. exception 2088 if (_pending_async_exception != NULL) { 2089 // Only overwrite an already pending exception, if it is not a threadDeath. 2090 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2091 2092 // We cannot call Exceptions::_throw(...) here because we cannot block 2093 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2094 2095 if (TraceExceptions) { 2096 ResourceMark rm; 2097 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2098 if (has_last_Java_frame() ) { 2099 frame f = last_frame(); 2100 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2101 } 2102 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2103 } 2104 _pending_async_exception = NULL; 2105 clear_has_async_exception(); 2106 } 2107 } 2108 2109 if (check_unsafe_error && 2110 condition == _async_unsafe_access_error && !has_pending_exception()) { 2111 condition = _no_async_condition; // done 2112 switch (thread_state()) { 2113 case _thread_in_vm: 2114 { 2115 JavaThread* THREAD = this; 2116 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2117 } 2118 case _thread_in_native: 2119 { 2120 ThreadInVMfromNative tiv(this); 2121 JavaThread* THREAD = this; 2122 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2123 } 2124 case _thread_in_Java: 2125 { 2126 ThreadInVMfromJava tiv(this); 2127 JavaThread* THREAD = this; 2128 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2129 } 2130 default: 2131 ShouldNotReachHere(); 2132 } 2133 } 2134 2135 assert(condition == _no_async_condition || has_pending_exception() || 2136 (!check_unsafe_error && condition == _async_unsafe_access_error), 2137 "must have handled the async condition, if no exception"); 2138 } 2139 2140 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2141 // 2142 // Check for pending external suspend. Internal suspend requests do 2143 // not use handle_special_runtime_exit_condition(). 2144 // If JNIEnv proxies are allowed, don't self-suspend if the target 2145 // thread is not the current thread. In older versions of jdbx, jdbx 2146 // threads could call into the VM with another thread's JNIEnv so we 2147 // can be here operating on behalf of a suspended thread (4432884). 2148 bool do_self_suspend = is_external_suspend_with_lock(); 2149 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2150 // 2151 // Because thread is external suspended the safepoint code will count 2152 // thread as at a safepoint. This can be odd because we can be here 2153 // as _thread_in_Java which would normally transition to _thread_blocked 2154 // at a safepoint. We would like to mark the thread as _thread_blocked 2155 // before calling java_suspend_self like all other callers of it but 2156 // we must then observe proper safepoint protocol. (We can't leave 2157 // _thread_blocked with a safepoint in progress). However we can be 2158 // here as _thread_in_native_trans so we can't use a normal transition 2159 // constructor/destructor pair because they assert on that type of 2160 // transition. We could do something like: 2161 // 2162 // JavaThreadState state = thread_state(); 2163 // set_thread_state(_thread_in_vm); 2164 // { 2165 // ThreadBlockInVM tbivm(this); 2166 // java_suspend_self() 2167 // } 2168 // set_thread_state(_thread_in_vm_trans); 2169 // if (safepoint) block; 2170 // set_thread_state(state); 2171 // 2172 // but that is pretty messy. Instead we just go with the way the 2173 // code has worked before and note that this is the only path to 2174 // java_suspend_self that doesn't put the thread in _thread_blocked 2175 // mode. 2176 2177 frame_anchor()->make_walkable(this); 2178 java_suspend_self(); 2179 2180 // We might be here for reasons in addition to the self-suspend request 2181 // so check for other async requests. 2182 } 2183 2184 if (check_asyncs) { 2185 check_and_handle_async_exceptions(); 2186 } 2187 } 2188 2189 void JavaThread::send_thread_stop(oop java_throwable) { 2190 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2191 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2192 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2193 2194 // Do not throw asynchronous exceptions against the compiler thread 2195 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2196 if (is_Compiler_thread()) return; 2197 2198 { 2199 // Actually throw the Throwable against the target Thread - however 2200 // only if there is no thread death exception installed already. 2201 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2202 // If the topmost frame is a runtime stub, then we are calling into 2203 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2204 // must deoptimize the caller before continuing, as the compiled exception handler table 2205 // may not be valid 2206 if (has_last_Java_frame()) { 2207 frame f = last_frame(); 2208 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2209 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2210 RegisterMap reg_map(this, UseBiasedLocking); 2211 frame compiled_frame = f.sender(®_map); 2212 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2213 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2214 } 2215 } 2216 } 2217 2218 // Set async. pending exception in thread. 2219 set_pending_async_exception(java_throwable); 2220 2221 if (TraceExceptions) { 2222 ResourceMark rm; 2223 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2224 } 2225 // for AbortVMOnException flag 2226 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2227 } 2228 } 2229 2230 2231 // Interrupt thread so it will wake up from a potential wait() 2232 Thread::interrupt(this); 2233 } 2234 2235 // External suspension mechanism. 2236 // 2237 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2238 // to any VM_locks and it is at a transition 2239 // Self-suspension will happen on the transition out of the vm. 2240 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2241 // 2242 // Guarantees on return: 2243 // + Target thread will not execute any new bytecode (that's why we need to 2244 // force a safepoint) 2245 // + Target thread will not enter any new monitors 2246 // 2247 void JavaThread::java_suspend() { 2248 { MutexLocker mu(Threads_lock); 2249 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2250 return; 2251 } 2252 } 2253 2254 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2255 if (!is_external_suspend()) { 2256 // a racing resume has cancelled us; bail out now 2257 return; 2258 } 2259 2260 // suspend is done 2261 uint32_t debug_bits = 0; 2262 // Warning: is_ext_suspend_completed() may temporarily drop the 2263 // SR_lock to allow the thread to reach a stable thread state if 2264 // it is currently in a transient thread state. 2265 if (is_ext_suspend_completed(false /* !called_by_wait */, 2266 SuspendRetryDelay, &debug_bits) ) { 2267 return; 2268 } 2269 } 2270 2271 VM_ForceSafepoint vm_suspend; 2272 VMThread::execute(&vm_suspend); 2273 } 2274 2275 // Part II of external suspension. 2276 // A JavaThread self suspends when it detects a pending external suspend 2277 // request. This is usually on transitions. It is also done in places 2278 // where continuing to the next transition would surprise the caller, 2279 // e.g., monitor entry. 2280 // 2281 // Returns the number of times that the thread self-suspended. 2282 // 2283 // Note: DO NOT call java_suspend_self() when you just want to block current 2284 // thread. java_suspend_self() is the second stage of cooperative 2285 // suspension for external suspend requests and should only be used 2286 // to complete an external suspend request. 2287 // 2288 int JavaThread::java_suspend_self() { 2289 int ret = 0; 2290 2291 // we are in the process of exiting so don't suspend 2292 if (is_exiting()) { 2293 clear_external_suspend(); 2294 return ret; 2295 } 2296 2297 assert(_anchor.walkable() || 2298 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2299 "must have walkable stack"); 2300 2301 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2302 2303 assert(!this->is_ext_suspended(), 2304 "a thread trying to self-suspend should not already be suspended"); 2305 2306 if (this->is_suspend_equivalent()) { 2307 // If we are self-suspending as a result of the lifting of a 2308 // suspend equivalent condition, then the suspend_equivalent 2309 // flag is not cleared until we set the ext_suspended flag so 2310 // that wait_for_ext_suspend_completion() returns consistent 2311 // results. 2312 this->clear_suspend_equivalent(); 2313 } 2314 2315 // A racing resume may have cancelled us before we grabbed SR_lock 2316 // above. Or another external suspend request could be waiting for us 2317 // by the time we return from SR_lock()->wait(). The thread 2318 // that requested the suspension may already be trying to walk our 2319 // stack and if we return now, we can change the stack out from under 2320 // it. This would be a "bad thing (TM)" and cause the stack walker 2321 // to crash. We stay self-suspended until there are no more pending 2322 // external suspend requests. 2323 while (is_external_suspend()) { 2324 ret++; 2325 this->set_ext_suspended(); 2326 2327 // _ext_suspended flag is cleared by java_resume() 2328 while (is_ext_suspended()) { 2329 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2330 } 2331 } 2332 2333 return ret; 2334 } 2335 2336 #ifdef ASSERT 2337 // verify the JavaThread has not yet been published in the Threads::list, and 2338 // hence doesn't need protection from concurrent access at this stage 2339 void JavaThread::verify_not_published() { 2340 if (!Threads_lock->owned_by_self()) { 2341 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2342 assert( !Threads::includes(this), 2343 "java thread shouldn't have been published yet!"); 2344 } 2345 else { 2346 assert( !Threads::includes(this), 2347 "java thread shouldn't have been published yet!"); 2348 } 2349 } 2350 #endif 2351 2352 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2353 // progress or when _suspend_flags is non-zero. 2354 // Current thread needs to self-suspend if there is a suspend request and/or 2355 // block if a safepoint is in progress. 2356 // Async exception ISN'T checked. 2357 // Note only the ThreadInVMfromNative transition can call this function 2358 // directly and when thread state is _thread_in_native_trans 2359 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2360 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2361 2362 JavaThread *curJT = JavaThread::current(); 2363 bool do_self_suspend = thread->is_external_suspend(); 2364 2365 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2366 2367 // If JNIEnv proxies are allowed, don't self-suspend if the target 2368 // thread is not the current thread. In older versions of jdbx, jdbx 2369 // threads could call into the VM with another thread's JNIEnv so we 2370 // can be here operating on behalf of a suspended thread (4432884). 2371 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2372 JavaThreadState state = thread->thread_state(); 2373 2374 // We mark this thread_blocked state as a suspend-equivalent so 2375 // that a caller to is_ext_suspend_completed() won't be confused. 2376 // The suspend-equivalent state is cleared by java_suspend_self(). 2377 thread->set_suspend_equivalent(); 2378 2379 // If the safepoint code sees the _thread_in_native_trans state, it will 2380 // wait until the thread changes to other thread state. There is no 2381 // guarantee on how soon we can obtain the SR_lock and complete the 2382 // self-suspend request. It would be a bad idea to let safepoint wait for 2383 // too long. Temporarily change the state to _thread_blocked to 2384 // let the VM thread know that this thread is ready for GC. The problem 2385 // of changing thread state is that safepoint could happen just after 2386 // java_suspend_self() returns after being resumed, and VM thread will 2387 // see the _thread_blocked state. We must check for safepoint 2388 // after restoring the state and make sure we won't leave while a safepoint 2389 // is in progress. 2390 thread->set_thread_state(_thread_blocked); 2391 thread->java_suspend_self(); 2392 thread->set_thread_state(state); 2393 // Make sure new state is seen by VM thread 2394 if (os::is_MP()) { 2395 if (UseMembar) { 2396 // Force a fence between the write above and read below 2397 OrderAccess::fence(); 2398 } else { 2399 // Must use this rather than serialization page in particular on Windows 2400 InterfaceSupport::serialize_memory(thread); 2401 } 2402 } 2403 } 2404 2405 if (SafepointSynchronize::do_call_back()) { 2406 // If we are safepointing, then block the caller which may not be 2407 // the same as the target thread (see above). 2408 SafepointSynchronize::block(curJT); 2409 } 2410 2411 if (thread->is_deopt_suspend()) { 2412 thread->clear_deopt_suspend(); 2413 RegisterMap map(thread, false); 2414 frame f = thread->last_frame(); 2415 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2416 f = f.sender(&map); 2417 } 2418 if (f.id() == thread->must_deopt_id()) { 2419 thread->clear_must_deopt_id(); 2420 f.deoptimize(thread); 2421 } else { 2422 fatal("missed deoptimization!"); 2423 } 2424 } 2425 } 2426 2427 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2428 // progress or when _suspend_flags is non-zero. 2429 // Current thread needs to self-suspend if there is a suspend request and/or 2430 // block if a safepoint is in progress. 2431 // Also check for pending async exception (not including unsafe access error). 2432 // Note only the native==>VM/Java barriers can call this function and when 2433 // thread state is _thread_in_native_trans. 2434 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2435 check_safepoint_and_suspend_for_native_trans(thread); 2436 2437 if (thread->has_async_exception()) { 2438 // We are in _thread_in_native_trans state, don't handle unsafe 2439 // access error since that may block. 2440 thread->check_and_handle_async_exceptions(false); 2441 } 2442 } 2443 2444 // This is a variant of the normal 2445 // check_special_condition_for_native_trans with slightly different 2446 // semantics for use by critical native wrappers. It does all the 2447 // normal checks but also performs the transition back into 2448 // thread_in_Java state. This is required so that critical natives 2449 // can potentially block and perform a GC if they are the last thread 2450 // exiting the GC_locker. 2451 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2452 check_special_condition_for_native_trans(thread); 2453 2454 // Finish the transition 2455 thread->set_thread_state(_thread_in_Java); 2456 2457 if (thread->do_critical_native_unlock()) { 2458 ThreadInVMfromJavaNoAsyncException tiv(thread); 2459 GC_locker::unlock_critical(thread); 2460 thread->clear_critical_native_unlock(); 2461 } 2462 } 2463 2464 // We need to guarantee the Threads_lock here, since resumes are not 2465 // allowed during safepoint synchronization 2466 // Can only resume from an external suspension 2467 void JavaThread::java_resume() { 2468 assert_locked_or_safepoint(Threads_lock); 2469 2470 // Sanity check: thread is gone, has started exiting or the thread 2471 // was not externally suspended. 2472 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2473 return; 2474 } 2475 2476 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2477 2478 clear_external_suspend(); 2479 2480 if (is_ext_suspended()) { 2481 clear_ext_suspended(); 2482 SR_lock()->notify_all(); 2483 } 2484 } 2485 2486 void JavaThread::create_stack_guard_pages() { 2487 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2488 address low_addr = stack_base() - stack_size(); 2489 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2490 2491 int allocate = os::allocate_stack_guard_pages(); 2492 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2493 2494 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2495 warning("Attempt to allocate stack guard pages failed."); 2496 return; 2497 } 2498 2499 if (os::guard_memory((char *) low_addr, len)) { 2500 _stack_guard_state = stack_guard_enabled; 2501 } else { 2502 warning("Attempt to protect stack guard pages failed."); 2503 if (os::uncommit_memory((char *) low_addr, len)) { 2504 warning("Attempt to deallocate stack guard pages failed."); 2505 } 2506 } 2507 } 2508 2509 void JavaThread::remove_stack_guard_pages() { 2510 assert(Thread::current() == this, "from different thread"); 2511 if (_stack_guard_state == stack_guard_unused) return; 2512 address low_addr = stack_base() - stack_size(); 2513 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2514 2515 if (os::allocate_stack_guard_pages()) { 2516 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2517 _stack_guard_state = stack_guard_unused; 2518 } else { 2519 warning("Attempt to deallocate stack guard pages failed."); 2520 } 2521 } else { 2522 if (_stack_guard_state == stack_guard_unused) return; 2523 if (os::unguard_memory((char *) low_addr, len)) { 2524 _stack_guard_state = stack_guard_unused; 2525 } else { 2526 warning("Attempt to unprotect stack guard pages failed."); 2527 } 2528 } 2529 } 2530 2531 void JavaThread::enable_stack_yellow_zone() { 2532 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2533 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2534 2535 // The base notation is from the stacks point of view, growing downward. 2536 // We need to adjust it to work correctly with guard_memory() 2537 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2538 2539 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2540 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2541 2542 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2543 _stack_guard_state = stack_guard_enabled; 2544 } else { 2545 warning("Attempt to guard stack yellow zone failed."); 2546 } 2547 enable_register_stack_guard(); 2548 } 2549 2550 void JavaThread::disable_stack_yellow_zone() { 2551 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2552 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2553 2554 // Simply return if called for a thread that does not use guard pages. 2555 if (_stack_guard_state == stack_guard_unused) return; 2556 2557 // The base notation is from the stacks point of view, growing downward. 2558 // We need to adjust it to work correctly with guard_memory() 2559 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2560 2561 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2562 _stack_guard_state = stack_guard_yellow_disabled; 2563 } else { 2564 warning("Attempt to unguard stack yellow zone failed."); 2565 } 2566 disable_register_stack_guard(); 2567 } 2568 2569 void JavaThread::enable_stack_red_zone() { 2570 // The base notation is from the stacks point of view, growing downward. 2571 // We need to adjust it to work correctly with guard_memory() 2572 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2573 address base = stack_red_zone_base() - stack_red_zone_size(); 2574 2575 guarantee(base < stack_base(),"Error calculating stack red zone"); 2576 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2577 2578 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2579 warning("Attempt to guard stack red zone failed."); 2580 } 2581 } 2582 2583 void JavaThread::disable_stack_red_zone() { 2584 // The base notation is from the stacks point of view, growing downward. 2585 // We need to adjust it to work correctly with guard_memory() 2586 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2587 address base = stack_red_zone_base() - stack_red_zone_size(); 2588 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2589 warning("Attempt to unguard stack red zone failed."); 2590 } 2591 } 2592 2593 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2594 // ignore is there is no stack 2595 if (!has_last_Java_frame()) return; 2596 // traverse the stack frames. Starts from top frame. 2597 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2598 frame* fr = fst.current(); 2599 f(fr, fst.register_map()); 2600 } 2601 } 2602 2603 2604 #ifndef PRODUCT 2605 // Deoptimization 2606 // Function for testing deoptimization 2607 void JavaThread::deoptimize() { 2608 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2609 StackFrameStream fst(this, UseBiasedLocking); 2610 bool deopt = false; // Dump stack only if a deopt actually happens. 2611 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2612 // Iterate over all frames in the thread and deoptimize 2613 for(; !fst.is_done(); fst.next()) { 2614 if(fst.current()->can_be_deoptimized()) { 2615 2616 if (only_at) { 2617 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2618 // consists of comma or carriage return separated numbers so 2619 // search for the current bci in that string. 2620 address pc = fst.current()->pc(); 2621 nmethod* nm = (nmethod*) fst.current()->cb(); 2622 ScopeDesc* sd = nm->scope_desc_at( pc); 2623 char buffer[8]; 2624 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2625 size_t len = strlen(buffer); 2626 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2627 while (found != NULL) { 2628 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2629 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2630 // Check that the bci found is bracketed by terminators. 2631 break; 2632 } 2633 found = strstr(found + 1, buffer); 2634 } 2635 if (!found) { 2636 continue; 2637 } 2638 } 2639 2640 if (DebugDeoptimization && !deopt) { 2641 deopt = true; // One-time only print before deopt 2642 tty->print_cr("[BEFORE Deoptimization]"); 2643 trace_frames(); 2644 trace_stack(); 2645 } 2646 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2647 } 2648 } 2649 2650 if (DebugDeoptimization && deopt) { 2651 tty->print_cr("[AFTER Deoptimization]"); 2652 trace_frames(); 2653 } 2654 } 2655 2656 2657 // Make zombies 2658 void JavaThread::make_zombies() { 2659 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2660 if (fst.current()->can_be_deoptimized()) { 2661 // it is a Java nmethod 2662 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2663 nm->make_not_entrant(); 2664 } 2665 } 2666 } 2667 #endif // PRODUCT 2668 2669 2670 void JavaThread::deoptimized_wrt_marked_nmethods() { 2671 if (!has_last_Java_frame()) return; 2672 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2673 StackFrameStream fst(this, UseBiasedLocking); 2674 for(; !fst.is_done(); fst.next()) { 2675 if (fst.current()->should_be_deoptimized()) { 2676 if (LogCompilation && xtty != NULL) { 2677 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2678 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2679 this->name(), nm != NULL ? nm->compile_id() : -1); 2680 } 2681 2682 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2683 } 2684 } 2685 } 2686 2687 2688 // GC support 2689 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2690 2691 void JavaThread::gc_epilogue() { 2692 frames_do(frame_gc_epilogue); 2693 } 2694 2695 2696 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2697 2698 void JavaThread::gc_prologue() { 2699 frames_do(frame_gc_prologue); 2700 } 2701 2702 // If the caller is a NamedThread, then remember, in the current scope, 2703 // the given JavaThread in its _processed_thread field. 2704 class RememberProcessedThread: public StackObj { 2705 NamedThread* _cur_thr; 2706 public: 2707 RememberProcessedThread(JavaThread* jthr) { 2708 Thread* thread = Thread::current(); 2709 if (thread->is_Named_thread()) { 2710 _cur_thr = (NamedThread *)thread; 2711 _cur_thr->set_processed_thread(jthr); 2712 } else { 2713 _cur_thr = NULL; 2714 } 2715 } 2716 2717 ~RememberProcessedThread() { 2718 if (_cur_thr) { 2719 _cur_thr->set_processed_thread(NULL); 2720 } 2721 } 2722 }; 2723 2724 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 2725 // Verify that the deferred card marks have been flushed. 2726 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2727 2728 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2729 // since there may be more than one thread using each ThreadProfiler. 2730 2731 // Traverse the GCHandles 2732 Thread::oops_do(f, cld_f, cf); 2733 2734 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2735 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2736 2737 if (has_last_Java_frame()) { 2738 // Record JavaThread to GC thread 2739 RememberProcessedThread rpt(this); 2740 2741 // Traverse the privileged stack 2742 if (_privileged_stack_top != NULL) { 2743 _privileged_stack_top->oops_do(f); 2744 } 2745 2746 // traverse the registered growable array 2747 if (_array_for_gc != NULL) { 2748 for (int index = 0; index < _array_for_gc->length(); index++) { 2749 f->do_oop(_array_for_gc->adr_at(index)); 2750 } 2751 } 2752 2753 // Traverse the monitor chunks 2754 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2755 chunk->oops_do(f); 2756 } 2757 2758 // Traverse the execution stack 2759 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2760 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2761 } 2762 } 2763 2764 // callee_target is never live across a gc point so NULL it here should 2765 // it still contain a methdOop. 2766 2767 set_callee_target(NULL); 2768 2769 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2770 // If we have deferred set_locals there might be oops waiting to be 2771 // written 2772 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2773 if (list != NULL) { 2774 for (int i = 0; i < list->length(); i++) { 2775 list->at(i)->oops_do(f); 2776 } 2777 } 2778 2779 // Traverse instance variables at the end since the GC may be moving things 2780 // around using this function 2781 f->do_oop((oop*) &_threadObj); 2782 f->do_oop((oop*) &_vm_result); 2783 f->do_oop((oop*) &_exception_oop); 2784 f->do_oop((oop*) &_pending_async_exception); 2785 2786 if (jvmti_thread_state() != NULL) { 2787 jvmti_thread_state()->oops_do(f); 2788 } 2789 } 2790 2791 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2792 Thread::nmethods_do(cf); // (super method is a no-op) 2793 2794 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2795 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2796 2797 if (has_last_Java_frame()) { 2798 // Traverse the execution stack 2799 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2800 fst.current()->nmethods_do(cf); 2801 } 2802 } 2803 } 2804 2805 void JavaThread::metadata_do(void f(Metadata*)) { 2806 Thread::metadata_do(f); 2807 if (has_last_Java_frame()) { 2808 // Traverse the execution stack to call f() on the methods in the stack 2809 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2810 fst.current()->metadata_do(f); 2811 } 2812 } else if (is_Compiler_thread()) { 2813 // need to walk ciMetadata in current compile tasks to keep alive. 2814 CompilerThread* ct = (CompilerThread*)this; 2815 if (ct->env() != NULL) { 2816 ct->env()->metadata_do(f); 2817 } 2818 } 2819 } 2820 2821 // Printing 2822 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2823 switch (_thread_state) { 2824 case _thread_uninitialized: return "_thread_uninitialized"; 2825 case _thread_new: return "_thread_new"; 2826 case _thread_new_trans: return "_thread_new_trans"; 2827 case _thread_in_native: return "_thread_in_native"; 2828 case _thread_in_native_trans: return "_thread_in_native_trans"; 2829 case _thread_in_vm: return "_thread_in_vm"; 2830 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2831 case _thread_in_Java: return "_thread_in_Java"; 2832 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2833 case _thread_blocked: return "_thread_blocked"; 2834 case _thread_blocked_trans: return "_thread_blocked_trans"; 2835 default: return "unknown thread state"; 2836 } 2837 } 2838 2839 #ifndef PRODUCT 2840 void JavaThread::print_thread_state_on(outputStream *st) const { 2841 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2842 }; 2843 void JavaThread::print_thread_state() const { 2844 print_thread_state_on(tty); 2845 }; 2846 #endif // PRODUCT 2847 2848 // Called by Threads::print() for VM_PrintThreads operation 2849 void JavaThread::print_on(outputStream *st) const { 2850 st->print("\"%s\" ", get_thread_name()); 2851 oop thread_oop = threadObj(); 2852 if (thread_oop != NULL) { 2853 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2854 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2855 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2856 } 2857 Thread::print_on(st); 2858 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2859 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2860 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2861 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2862 } 2863 #ifndef PRODUCT 2864 print_thread_state_on(st); 2865 _safepoint_state->print_on(st); 2866 #endif // PRODUCT 2867 } 2868 2869 // Called by fatal error handler. The difference between this and 2870 // JavaThread::print() is that we can't grab lock or allocate memory. 2871 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2872 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2873 oop thread_obj = threadObj(); 2874 if (thread_obj != NULL) { 2875 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2876 } 2877 st->print(" ["); 2878 st->print("%s", _get_thread_state_name(_thread_state)); 2879 if (osthread()) { 2880 st->print(", id=%d", osthread()->thread_id()); 2881 } 2882 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2883 _stack_base - _stack_size, _stack_base); 2884 st->print("]"); 2885 return; 2886 } 2887 2888 // Verification 2889 2890 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2891 2892 void JavaThread::verify() { 2893 // Verify oops in the thread. 2894 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2895 2896 // Verify the stack frames. 2897 frames_do(frame_verify); 2898 } 2899 2900 // CR 6300358 (sub-CR 2137150) 2901 // Most callers of this method assume that it can't return NULL but a 2902 // thread may not have a name whilst it is in the process of attaching to 2903 // the VM - see CR 6412693, and there are places where a JavaThread can be 2904 // seen prior to having it's threadObj set (eg JNI attaching threads and 2905 // if vm exit occurs during initialization). These cases can all be accounted 2906 // for such that this method never returns NULL. 2907 const char* JavaThread::get_thread_name() const { 2908 #ifdef ASSERT 2909 // early safepoints can hit while current thread does not yet have TLS 2910 if (!SafepointSynchronize::is_at_safepoint()) { 2911 Thread *cur = Thread::current(); 2912 if (!(cur->is_Java_thread() && cur == this)) { 2913 // Current JavaThreads are allowed to get their own name without 2914 // the Threads_lock. 2915 assert_locked_or_safepoint(Threads_lock); 2916 } 2917 } 2918 #endif // ASSERT 2919 return get_thread_name_string(); 2920 } 2921 2922 // Returns a non-NULL representation of this thread's name, or a suitable 2923 // descriptive string if there is no set name 2924 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2925 const char* name_str; 2926 oop thread_obj = threadObj(); 2927 if (thread_obj != NULL) { 2928 typeArrayOop name = java_lang_Thread::name(thread_obj); 2929 if (name != NULL) { 2930 if (buf == NULL) { 2931 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2932 } 2933 else { 2934 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2935 } 2936 } 2937 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2938 name_str = "<no-name - thread is attaching>"; 2939 } 2940 else { 2941 name_str = Thread::name(); 2942 } 2943 } 2944 else { 2945 name_str = Thread::name(); 2946 } 2947 assert(name_str != NULL, "unexpected NULL thread name"); 2948 return name_str; 2949 } 2950 2951 2952 const char* JavaThread::get_threadgroup_name() const { 2953 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2954 oop thread_obj = threadObj(); 2955 if (thread_obj != NULL) { 2956 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2957 if (thread_group != NULL) { 2958 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2959 // ThreadGroup.name can be null 2960 if (name != NULL) { 2961 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2962 return str; 2963 } 2964 } 2965 } 2966 return NULL; 2967 } 2968 2969 const char* JavaThread::get_parent_name() const { 2970 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2971 oop thread_obj = threadObj(); 2972 if (thread_obj != NULL) { 2973 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2974 if (thread_group != NULL) { 2975 oop parent = java_lang_ThreadGroup::parent(thread_group); 2976 if (parent != NULL) { 2977 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2978 // ThreadGroup.name can be null 2979 if (name != NULL) { 2980 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2981 return str; 2982 } 2983 } 2984 } 2985 } 2986 return NULL; 2987 } 2988 2989 ThreadPriority JavaThread::java_priority() const { 2990 oop thr_oop = threadObj(); 2991 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2992 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2993 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2994 return priority; 2995 } 2996 2997 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2998 2999 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3000 // Link Java Thread object <-> C++ Thread 3001 3002 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3003 // and put it into a new Handle. The Handle "thread_oop" can then 3004 // be used to pass the C++ thread object to other methods. 3005 3006 // Set the Java level thread object (jthread) field of the 3007 // new thread (a JavaThread *) to C++ thread object using the 3008 // "thread_oop" handle. 3009 3010 // Set the thread field (a JavaThread *) of the 3011 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3012 3013 Handle thread_oop(Thread::current(), 3014 JNIHandles::resolve_non_null(jni_thread)); 3015 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3016 "must be initialized"); 3017 set_threadObj(thread_oop()); 3018 java_lang_Thread::set_thread(thread_oop(), this); 3019 3020 if (prio == NoPriority) { 3021 prio = java_lang_Thread::priority(thread_oop()); 3022 assert(prio != NoPriority, "A valid priority should be present"); 3023 } 3024 3025 // Push the Java priority down to the native thread; needs Threads_lock 3026 Thread::set_priority(this, prio); 3027 3028 // Add the new thread to the Threads list and set it in motion. 3029 // We must have threads lock in order to call Threads::add. 3030 // It is crucial that we do not block before the thread is 3031 // added to the Threads list for if a GC happens, then the java_thread oop 3032 // will not be visited by GC. 3033 Threads::add(this); 3034 } 3035 3036 oop JavaThread::current_park_blocker() { 3037 // Support for JSR-166 locks 3038 oop thread_oop = threadObj(); 3039 if (thread_oop != NULL && 3040 JDK_Version::current().supports_thread_park_blocker()) { 3041 return java_lang_Thread::park_blocker(thread_oop); 3042 } 3043 return NULL; 3044 } 3045 3046 3047 void JavaThread::print_stack_on(outputStream* st) { 3048 if (!has_last_Java_frame()) return; 3049 ResourceMark rm; 3050 HandleMark hm; 3051 3052 RegisterMap reg_map(this); 3053 vframe* start_vf = last_java_vframe(®_map); 3054 int count = 0; 3055 for (vframe* f = start_vf; f; f = f->sender() ) { 3056 if (f->is_java_frame()) { 3057 javaVFrame* jvf = javaVFrame::cast(f); 3058 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3059 3060 // Print out lock information 3061 if (JavaMonitorsInStackTrace) { 3062 jvf->print_lock_info_on(st, count); 3063 } 3064 } else { 3065 // Ignore non-Java frames 3066 } 3067 3068 // Bail-out case for too deep stacks 3069 count++; 3070 if (MaxJavaStackTraceDepth == count) return; 3071 } 3072 } 3073 3074 3075 // JVMTI PopFrame support 3076 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3077 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3078 if (in_bytes(size_in_bytes) != 0) { 3079 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3080 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3081 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3082 } 3083 } 3084 3085 void* JavaThread::popframe_preserved_args() { 3086 return _popframe_preserved_args; 3087 } 3088 3089 ByteSize JavaThread::popframe_preserved_args_size() { 3090 return in_ByteSize(_popframe_preserved_args_size); 3091 } 3092 3093 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3094 int sz = in_bytes(popframe_preserved_args_size()); 3095 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3096 return in_WordSize(sz / wordSize); 3097 } 3098 3099 void JavaThread::popframe_free_preserved_args() { 3100 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3101 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3102 _popframe_preserved_args = NULL; 3103 _popframe_preserved_args_size = 0; 3104 } 3105 3106 #ifndef PRODUCT 3107 3108 void JavaThread::trace_frames() { 3109 tty->print_cr("[Describe stack]"); 3110 int frame_no = 1; 3111 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3112 tty->print(" %d. ", frame_no++); 3113 fst.current()->print_value_on(tty,this); 3114 tty->cr(); 3115 } 3116 } 3117 3118 class PrintAndVerifyOopClosure: public OopClosure { 3119 protected: 3120 template <class T> inline void do_oop_work(T* p) { 3121 oop obj = oopDesc::load_decode_heap_oop(p); 3122 if (obj == NULL) return; 3123 tty->print(INTPTR_FORMAT ": ", p); 3124 if (obj->is_oop_or_null()) { 3125 if (obj->is_objArray()) { 3126 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3127 } else { 3128 obj->print(); 3129 } 3130 } else { 3131 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3132 } 3133 tty->cr(); 3134 } 3135 public: 3136 virtual void do_oop(oop* p) { do_oop_work(p); } 3137 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3138 }; 3139 3140 3141 static void oops_print(frame* f, const RegisterMap *map) { 3142 PrintAndVerifyOopClosure print; 3143 f->print_value(); 3144 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3145 } 3146 3147 // Print our all the locations that contain oops and whether they are 3148 // valid or not. This useful when trying to find the oldest frame 3149 // where an oop has gone bad since the frame walk is from youngest to 3150 // oldest. 3151 void JavaThread::trace_oops() { 3152 tty->print_cr("[Trace oops]"); 3153 frames_do(oops_print); 3154 } 3155 3156 3157 #ifdef ASSERT 3158 // Print or validate the layout of stack frames 3159 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3160 ResourceMark rm; 3161 PRESERVE_EXCEPTION_MARK; 3162 FrameValues values; 3163 int frame_no = 0; 3164 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3165 fst.current()->describe(values, ++frame_no); 3166 if (depth == frame_no) break; 3167 } 3168 if (validate_only) { 3169 values.validate(); 3170 } else { 3171 tty->print_cr("[Describe stack layout]"); 3172 values.print(this); 3173 } 3174 } 3175 #endif 3176 3177 void JavaThread::trace_stack_from(vframe* start_vf) { 3178 ResourceMark rm; 3179 int vframe_no = 1; 3180 for (vframe* f = start_vf; f; f = f->sender() ) { 3181 if (f->is_java_frame()) { 3182 javaVFrame::cast(f)->print_activation(vframe_no++); 3183 } else { 3184 f->print(); 3185 } 3186 if (vframe_no > StackPrintLimit) { 3187 tty->print_cr("...<more frames>..."); 3188 return; 3189 } 3190 } 3191 } 3192 3193 3194 void JavaThread::trace_stack() { 3195 if (!has_last_Java_frame()) return; 3196 ResourceMark rm; 3197 HandleMark hm; 3198 RegisterMap reg_map(this); 3199 trace_stack_from(last_java_vframe(®_map)); 3200 } 3201 3202 3203 #endif // PRODUCT 3204 3205 3206 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3207 assert(reg_map != NULL, "a map must be given"); 3208 frame f = last_frame(); 3209 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3210 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3211 } 3212 return NULL; 3213 } 3214 3215 3216 Klass* JavaThread::security_get_caller_class(int depth) { 3217 vframeStream vfst(this); 3218 vfst.security_get_caller_frame(depth); 3219 if (!vfst.at_end()) { 3220 return vfst.method()->method_holder(); 3221 } 3222 return NULL; 3223 } 3224 3225 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3226 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3227 CompileBroker::compiler_thread_loop(); 3228 } 3229 3230 // Create a CompilerThread 3231 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3232 : JavaThread(&compiler_thread_entry) { 3233 _env = NULL; 3234 _log = NULL; 3235 _task = NULL; 3236 _queue = queue; 3237 _counters = counters; 3238 _buffer_blob = NULL; 3239 _scanned_nmethod = NULL; 3240 3241 #ifndef PRODUCT 3242 _ideal_graph_printer = NULL; 3243 #endif 3244 } 3245 3246 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 3247 JavaThread::oops_do(f, cld_f, cf); 3248 if (_scanned_nmethod != NULL && cf != NULL) { 3249 // Safepoints can occur when the sweeper is scanning an nmethod so 3250 // process it here to make sure it isn't unloaded in the middle of 3251 // a scan. 3252 cf->do_code_blob(_scanned_nmethod); 3253 } 3254 } 3255 3256 // ======= Threads ======== 3257 3258 // The Threads class links together all active threads, and provides 3259 // operations over all threads. It is protected by its own Mutex 3260 // lock, which is also used in other contexts to protect thread 3261 // operations from having the thread being operated on from exiting 3262 // and going away unexpectedly (e.g., safepoint synchronization) 3263 3264 JavaThread* Threads::_thread_list = NULL; 3265 int Threads::_number_of_threads = 0; 3266 int Threads::_number_of_non_daemon_threads = 0; 3267 int Threads::_return_code = 0; 3268 size_t JavaThread::_stack_size_at_create = 0; 3269 #ifdef ASSERT 3270 bool Threads::_vm_complete = false; 3271 #endif 3272 3273 // All JavaThreads 3274 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3275 3276 void os_stream(); 3277 3278 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3279 void Threads::threads_do(ThreadClosure* tc) { 3280 assert_locked_or_safepoint(Threads_lock); 3281 // ALL_JAVA_THREADS iterates through all JavaThreads 3282 ALL_JAVA_THREADS(p) { 3283 tc->do_thread(p); 3284 } 3285 // Someday we could have a table or list of all non-JavaThreads. 3286 // For now, just manually iterate through them. 3287 tc->do_thread(VMThread::vm_thread()); 3288 Universe::heap()->gc_threads_do(tc); 3289 WatcherThread *wt = WatcherThread::watcher_thread(); 3290 // Strictly speaking, the following NULL check isn't sufficient to make sure 3291 // the data for WatcherThread is still valid upon being examined. However, 3292 // considering that WatchThread terminates when the VM is on the way to 3293 // exit at safepoint, the chance of the above is extremely small. The right 3294 // way to prevent termination of WatcherThread would be to acquire 3295 // Terminator_lock, but we can't do that without violating the lock rank 3296 // checking in some cases. 3297 if (wt != NULL) 3298 tc->do_thread(wt); 3299 3300 // If CompilerThreads ever become non-JavaThreads, add them here 3301 } 3302 3303 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3304 3305 extern void JDK_Version_init(); 3306 3307 // Check version 3308 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3309 3310 // Initialize the output stream module 3311 ostream_init(); 3312 3313 // Process java launcher properties. 3314 Arguments::process_sun_java_launcher_properties(args); 3315 3316 // Initialize the os module before using TLS 3317 os::init(); 3318 3319 // Initialize system properties. 3320 Arguments::init_system_properties(); 3321 3322 // So that JDK version can be used as a discrimintor when parsing arguments 3323 JDK_Version_init(); 3324 3325 // Update/Initialize System properties after JDK version number is known 3326 Arguments::init_version_specific_system_properties(); 3327 3328 // Parse arguments 3329 jint parse_result = Arguments::parse(args); 3330 if (parse_result != JNI_OK) return parse_result; 3331 3332 if (PauseAtStartup) { 3333 os::pause(); 3334 } 3335 3336 #ifndef USDT2 3337 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3338 #else /* USDT2 */ 3339 HOTSPOT_VM_INIT_BEGIN(); 3340 #endif /* USDT2 */ 3341 3342 // Record VM creation timing statistics 3343 TraceVmCreationTime create_vm_timer; 3344 create_vm_timer.start(); 3345 3346 // Timing (must come after argument parsing) 3347 TraceTime timer("Create VM", TraceStartupTime); 3348 3349 // Initialize the os module after parsing the args 3350 jint os_init_2_result = os::init_2(); 3351 if (os_init_2_result != JNI_OK) return os_init_2_result; 3352 3353 jint adjust_after_os_result = Arguments::adjust_after_os(); 3354 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3355 3356 // intialize TLS 3357 ThreadLocalStorage::init(); 3358 3359 // Bootstrap native memory tracking, so it can start recording memory 3360 // activities before worker thread is started. This is the first phase 3361 // of bootstrapping, VM is currently running in single-thread mode. 3362 MemTracker::bootstrap_single_thread(); 3363 3364 // Initialize output stream logging 3365 ostream_init_log(); 3366 3367 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3368 // Must be before create_vm_init_agents() 3369 if (Arguments::init_libraries_at_startup()) { 3370 convert_vm_init_libraries_to_agents(); 3371 } 3372 3373 // Launch -agentlib/-agentpath and converted -Xrun agents 3374 if (Arguments::init_agents_at_startup()) { 3375 create_vm_init_agents(); 3376 } 3377 3378 // Initialize Threads state 3379 _thread_list = NULL; 3380 _number_of_threads = 0; 3381 _number_of_non_daemon_threads = 0; 3382 3383 // Initialize global data structures and create system classes in heap 3384 vm_init_globals(); 3385 3386 // Attach the main thread to this os thread 3387 JavaThread* main_thread = new JavaThread(); 3388 main_thread->set_thread_state(_thread_in_vm); 3389 // must do this before set_active_handles and initialize_thread_local_storage 3390 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3391 // change the stack size recorded here to one based on the java thread 3392 // stacksize. This adjusted size is what is used to figure the placement 3393 // of the guard pages. 3394 main_thread->record_stack_base_and_size(); 3395 main_thread->initialize_thread_local_storage(); 3396 3397 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3398 3399 if (!main_thread->set_as_starting_thread()) { 3400 vm_shutdown_during_initialization( 3401 "Failed necessary internal allocation. Out of swap space"); 3402 delete main_thread; 3403 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3404 return JNI_ENOMEM; 3405 } 3406 3407 // Enable guard page *after* os::create_main_thread(), otherwise it would 3408 // crash Linux VM, see notes in os_linux.cpp. 3409 main_thread->create_stack_guard_pages(); 3410 3411 // Initialize Java-Level synchronization subsystem 3412 ObjectMonitor::Initialize() ; 3413 3414 // Second phase of bootstrapping, VM is about entering multi-thread mode 3415 MemTracker::bootstrap_multi_thread(); 3416 3417 // Initialize global modules 3418 jint status = init_globals(); 3419 if (status != JNI_OK) { 3420 delete main_thread; 3421 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3422 return status; 3423 } 3424 3425 // Should be done after the heap is fully created 3426 main_thread->cache_global_variables(); 3427 3428 HandleMark hm; 3429 3430 { MutexLocker mu(Threads_lock); 3431 Threads::add(main_thread); 3432 } 3433 3434 // Any JVMTI raw monitors entered in onload will transition into 3435 // real raw monitor. VM is setup enough here for raw monitor enter. 3436 JvmtiExport::transition_pending_onload_raw_monitors(); 3437 3438 // Fully start NMT 3439 MemTracker::start(); 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 #ifndef USDT2 3565 HS_DTRACE_PROBE(hotspot, vm__init__end); 3566 #else /* USDT2 */ 3567 HOTSPOT_VM_INIT_END(); 3568 #endif /* USDT2 */ 3569 3570 // record VM initialization completion time 3571 #if INCLUDE_MANAGEMENT 3572 Management::record_vm_init_completed(); 3573 #endif // INCLUDE_MANAGEMENT 3574 3575 // Compute system loader. Note that this has to occur after set_init_completed, since 3576 // valid exceptions may be thrown in the process. 3577 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3578 // set_init_completed has just been called, causing exceptions not to be shortcut 3579 // anymore. We call vm_exit_during_initialization directly instead. 3580 SystemDictionary::compute_java_system_loader(THREAD); 3581 if (HAS_PENDING_EXCEPTION) { 3582 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3583 } 3584 3585 #if INCLUDE_ALL_GCS 3586 // Support for ConcurrentMarkSweep. This should be cleaned up 3587 // and better encapsulated. The ugly nested if test would go away 3588 // once things are properly refactored. XXX YSR 3589 if (UseConcMarkSweepGC || UseG1GC) { 3590 if (UseConcMarkSweepGC) { 3591 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3592 } else { 3593 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3594 } 3595 if (HAS_PENDING_EXCEPTION) { 3596 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3597 } 3598 } 3599 #endif // INCLUDE_ALL_GCS 3600 3601 // Always call even when there are not JVMTI environments yet, since environments 3602 // may be attached late and JVMTI must track phases of VM execution 3603 JvmtiExport::enter_live_phase(); 3604 3605 // Signal Dispatcher needs to be started before VMInit event is posted 3606 os::signal_init(); 3607 3608 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3609 if (!DisableAttachMechanism) { 3610 AttachListener::vm_start(); 3611 if (StartAttachListener || AttachListener::init_at_startup()) { 3612 AttachListener::init(); 3613 } 3614 } 3615 3616 // Launch -Xrun agents 3617 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3618 // back-end can launch with -Xdebug -Xrunjdwp. 3619 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3620 create_vm_init_libraries(); 3621 } 3622 3623 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3624 JvmtiExport::post_vm_initialized(); 3625 3626 if (TRACE_START() != JNI_OK) { 3627 vm_exit_during_initialization("Failed to start tracing backend."); 3628 } 3629 3630 if (CleanChunkPoolAsync) { 3631 Chunk::start_chunk_pool_cleaner_task(); 3632 } 3633 3634 // initialize compiler(s) 3635 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3636 CompileBroker::compilation_init(); 3637 #endif 3638 3639 if (EnableInvokeDynamic) { 3640 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3641 // It is done after compilers are initialized, because otherwise compilations of 3642 // signature polymorphic MH intrinsics can be missed 3643 // (see SystemDictionary::find_method_handle_intrinsic). 3644 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK_0); 3645 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK_0); 3646 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK_0); 3647 } 3648 3649 #if INCLUDE_MANAGEMENT 3650 Management::initialize(THREAD); 3651 #endif // INCLUDE_MANAGEMENT 3652 3653 if (HAS_PENDING_EXCEPTION) { 3654 // management agent fails to start possibly due to 3655 // configuration problem and is responsible for printing 3656 // stack trace if appropriate. Simply exit VM. 3657 vm_exit(1); 3658 } 3659 3660 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3661 if (MemProfiling) MemProfiler::engage(); 3662 StatSampler::engage(); 3663 if (CheckJNICalls) JniPeriodicChecker::engage(); 3664 3665 BiasedLocking::init(); 3666 3667 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3668 call_postVMInitHook(THREAD); 3669 // The Java side of PostVMInitHook.run must deal with all 3670 // exceptions and provide means of diagnosis. 3671 if (HAS_PENDING_EXCEPTION) { 3672 CLEAR_PENDING_EXCEPTION; 3673 } 3674 } 3675 3676 { 3677 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3678 // Make sure the watcher thread can be started by WatcherThread::start() 3679 // or by dynamic enrollment. 3680 WatcherThread::make_startable(); 3681 // Start up the WatcherThread if there are any periodic tasks 3682 // NOTE: All PeriodicTasks should be registered by now. If they 3683 // aren't, late joiners might appear to start slowly (we might 3684 // take a while to process their first tick). 3685 if (PeriodicTask::num_tasks() > 0) { 3686 WatcherThread::start(); 3687 } 3688 } 3689 3690 // Give os specific code one last chance to start 3691 os::init_3(); 3692 3693 create_vm_timer.end(); 3694 #ifdef ASSERT 3695 _vm_complete = true; 3696 #endif 3697 return JNI_OK; 3698 } 3699 3700 // type for the Agent_OnLoad and JVM_OnLoad entry points 3701 extern "C" { 3702 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3703 } 3704 // Find a command line agent library and return its entry point for 3705 // -agentlib: -agentpath: -Xrun 3706 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3707 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3708 OnLoadEntry_t on_load_entry = NULL; 3709 void *library = NULL; 3710 3711 if (!agent->valid()) { 3712 char buffer[JVM_MAXPATHLEN]; 3713 char ebuf[1024]; 3714 const char *name = agent->name(); 3715 const char *msg = "Could not find agent library "; 3716 3717 // First check to see if agent is statcally linked into executable 3718 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3719 library = agent->os_lib(); 3720 } else if (agent->is_absolute_path()) { 3721 library = os::dll_load(name, ebuf, sizeof ebuf); 3722 if (library == NULL) { 3723 const char *sub_msg = " in absolute path, with error: "; 3724 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3725 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3726 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3727 // If we can't find the agent, exit. 3728 vm_exit_during_initialization(buf, NULL); 3729 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3730 } 3731 } else { 3732 // Try to load the agent from the standard dll directory 3733 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3734 name)) { 3735 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3736 } 3737 if (library == NULL) { // Try the local directory 3738 char ns[1] = {0}; 3739 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3740 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3741 } 3742 if (library == NULL) { 3743 const char *sub_msg = " on the library path, with error: "; 3744 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3745 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3746 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3747 // If we can't find the agent, exit. 3748 vm_exit_during_initialization(buf, NULL); 3749 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3750 } 3751 } 3752 } 3753 agent->set_os_lib(library); 3754 agent->set_valid(); 3755 } 3756 3757 // Find the OnLoad function. 3758 on_load_entry = 3759 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3760 false, 3761 on_load_symbols, 3762 num_symbol_entries)); 3763 return on_load_entry; 3764 } 3765 3766 // Find the JVM_OnLoad entry point 3767 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3768 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3769 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3770 } 3771 3772 // Find the Agent_OnLoad entry point 3773 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3774 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3775 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3776 } 3777 3778 // For backwards compatibility with -Xrun 3779 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3780 // treated like -agentpath: 3781 // Must be called before agent libraries are created 3782 void Threads::convert_vm_init_libraries_to_agents() { 3783 AgentLibrary* agent; 3784 AgentLibrary* next; 3785 3786 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3787 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3788 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3789 3790 // If there is an JVM_OnLoad function it will get called later, 3791 // otherwise see if there is an Agent_OnLoad 3792 if (on_load_entry == NULL) { 3793 on_load_entry = lookup_agent_on_load(agent); 3794 if (on_load_entry != NULL) { 3795 // switch it to the agent list -- so that Agent_OnLoad will be called, 3796 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3797 Arguments::convert_library_to_agent(agent); 3798 } else { 3799 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3800 } 3801 } 3802 } 3803 } 3804 3805 // Create agents for -agentlib: -agentpath: and converted -Xrun 3806 // Invokes Agent_OnLoad 3807 // Called very early -- before JavaThreads exist 3808 void Threads::create_vm_init_agents() { 3809 extern struct JavaVM_ main_vm; 3810 AgentLibrary* agent; 3811 3812 JvmtiExport::enter_onload_phase(); 3813 3814 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3815 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3816 3817 if (on_load_entry != NULL) { 3818 // Invoke the Agent_OnLoad function 3819 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3820 if (err != JNI_OK) { 3821 vm_exit_during_initialization("agent library failed to init", agent->name()); 3822 } 3823 } else { 3824 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3825 } 3826 } 3827 JvmtiExport::enter_primordial_phase(); 3828 } 3829 3830 extern "C" { 3831 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3832 } 3833 3834 void Threads::shutdown_vm_agents() { 3835 // Send any Agent_OnUnload notifications 3836 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3837 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3838 extern struct JavaVM_ main_vm; 3839 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3840 3841 // Find the Agent_OnUnload function. 3842 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3843 os::find_agent_function(agent, 3844 false, 3845 on_unload_symbols, 3846 num_symbol_entries)); 3847 3848 // Invoke the Agent_OnUnload function 3849 if (unload_entry != NULL) { 3850 JavaThread* thread = JavaThread::current(); 3851 ThreadToNativeFromVM ttn(thread); 3852 HandleMark hm(thread); 3853 (*unload_entry)(&main_vm); 3854 } 3855 } 3856 } 3857 3858 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3859 // Invokes JVM_OnLoad 3860 void Threads::create_vm_init_libraries() { 3861 extern struct JavaVM_ main_vm; 3862 AgentLibrary* agent; 3863 3864 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3865 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3866 3867 if (on_load_entry != NULL) { 3868 // Invoke the JVM_OnLoad function 3869 JavaThread* thread = JavaThread::current(); 3870 ThreadToNativeFromVM ttn(thread); 3871 HandleMark hm(thread); 3872 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3873 if (err != JNI_OK) { 3874 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3875 } 3876 } else { 3877 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3878 } 3879 } 3880 } 3881 3882 // Last thread running calls java.lang.Shutdown.shutdown() 3883 void JavaThread::invoke_shutdown_hooks() { 3884 HandleMark hm(this); 3885 3886 // We could get here with a pending exception, if so clear it now. 3887 if (this->has_pending_exception()) { 3888 this->clear_pending_exception(); 3889 } 3890 3891 EXCEPTION_MARK; 3892 Klass* k = 3893 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3894 THREAD); 3895 if (k != NULL) { 3896 // SystemDictionary::resolve_or_null will return null if there was 3897 // an exception. If we cannot load the Shutdown class, just don't 3898 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3899 // and finalizers (if runFinalizersOnExit is set) won't be run. 3900 // Note that if a shutdown hook was registered or runFinalizersOnExit 3901 // was called, the Shutdown class would have already been loaded 3902 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3903 instanceKlassHandle shutdown_klass (THREAD, k); 3904 JavaValue result(T_VOID); 3905 JavaCalls::call_static(&result, 3906 shutdown_klass, 3907 vmSymbols::shutdown_method_name(), 3908 vmSymbols::void_method_signature(), 3909 THREAD); 3910 } 3911 CLEAR_PENDING_EXCEPTION; 3912 } 3913 3914 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3915 // the program falls off the end of main(). Another VM exit path is through 3916 // vm_exit() when the program calls System.exit() to return a value or when 3917 // there is a serious error in VM. The two shutdown paths are not exactly 3918 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3919 // and VM_Exit op at VM level. 3920 // 3921 // Shutdown sequence: 3922 // + Shutdown native memory tracking if it is on 3923 // + Wait until we are the last non-daemon thread to execute 3924 // <-- every thing is still working at this moment --> 3925 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3926 // shutdown hooks, run finalizers if finalization-on-exit 3927 // + Call before_exit(), prepare for VM exit 3928 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3929 // currently the only user of this mechanism is File.deleteOnExit()) 3930 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3931 // post thread end and vm death events to JVMTI, 3932 // stop signal thread 3933 // + Call JavaThread::exit(), it will: 3934 // > release JNI handle blocks, remove stack guard pages 3935 // > remove this thread from Threads list 3936 // <-- no more Java code from this thread after this point --> 3937 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3938 // the compiler threads at safepoint 3939 // <-- do not use anything that could get blocked by Safepoint --> 3940 // + Disable tracing at JNI/JVM barriers 3941 // + Set _vm_exited flag for threads that are still running native code 3942 // + Delete this thread 3943 // + Call exit_globals() 3944 // > deletes tty 3945 // > deletes PerfMemory resources 3946 // + Return to caller 3947 3948 bool Threads::destroy_vm() { 3949 JavaThread* thread = JavaThread::current(); 3950 3951 #ifdef ASSERT 3952 _vm_complete = false; 3953 #endif 3954 // Wait until we are the last non-daemon thread to execute 3955 { MutexLocker nu(Threads_lock); 3956 while (Threads::number_of_non_daemon_threads() > 1 ) 3957 // This wait should make safepoint checks, wait without a timeout, 3958 // and wait as a suspend-equivalent condition. 3959 // 3960 // Note: If the FlatProfiler is running and this thread is waiting 3961 // for another non-daemon thread to finish, then the FlatProfiler 3962 // is waiting for the external suspend request on this thread to 3963 // complete. wait_for_ext_suspend_completion() will eventually 3964 // timeout, but that takes time. Making this wait a suspend- 3965 // equivalent condition solves that timeout problem. 3966 // 3967 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3968 Mutex::_as_suspend_equivalent_flag); 3969 } 3970 3971 // Hang forever on exit if we are reporting an error. 3972 if (ShowMessageBoxOnError && is_error_reported()) { 3973 os::infinite_sleep(); 3974 } 3975 os::wait_for_keypress_at_exit(); 3976 3977 if (JDK_Version::is_jdk12x_version()) { 3978 // We are the last thread running, so check if finalizers should be run. 3979 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3980 HandleMark rm(thread); 3981 Universe::run_finalizers_on_exit(); 3982 } else { 3983 // run Java level shutdown hooks 3984 thread->invoke_shutdown_hooks(); 3985 } 3986 3987 before_exit(thread); 3988 3989 thread->exit(true); 3990 3991 // Stop VM thread. 3992 { 3993 // 4945125 The vm thread comes to a safepoint during exit. 3994 // GC vm_operations can get caught at the safepoint, and the 3995 // heap is unparseable if they are caught. Grab the Heap_lock 3996 // to prevent this. The GC vm_operations will not be able to 3997 // queue until after the vm thread is dead. 3998 // After this point, we'll never emerge out of the safepoint before 3999 // the VM exits, so concurrent GC threads do not need to be explicitly 4000 // stopped; they remain inactive until the process exits. 4001 // Note: some concurrent G1 threads may be running during a safepoint, 4002 // but these will not be accessing the heap, just some G1-specific side 4003 // data structures that are not accessed by any other threads but them 4004 // after this point in a terminal safepoint. 4005 4006 MutexLocker ml(Heap_lock); 4007 4008 VMThread::wait_for_vm_thread_exit(); 4009 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4010 VMThread::destroy(); 4011 } 4012 4013 // clean up ideal graph printers 4014 #if defined(COMPILER2) && !defined(PRODUCT) 4015 IdealGraphPrinter::clean_up(); 4016 #endif 4017 4018 // Now, all Java threads are gone except daemon threads. Daemon threads 4019 // running Java code or in VM are stopped by the Safepoint. However, 4020 // daemon threads executing native code are still running. But they 4021 // will be stopped at native=>Java/VM barriers. Note that we can't 4022 // simply kill or suspend them, as it is inherently deadlock-prone. 4023 4024 #ifndef PRODUCT 4025 // disable function tracing at JNI/JVM barriers 4026 TraceJNICalls = false; 4027 TraceJVMCalls = false; 4028 TraceRuntimeCalls = false; 4029 #endif 4030 4031 VM_Exit::set_vm_exited(); 4032 4033 notify_vm_shutdown(); 4034 4035 delete thread; 4036 4037 // exit_globals() will delete tty 4038 exit_globals(); 4039 4040 return true; 4041 } 4042 4043 4044 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4045 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4046 return is_supported_jni_version(version); 4047 } 4048 4049 4050 jboolean Threads::is_supported_jni_version(jint version) { 4051 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4052 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4053 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4054 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4055 return JNI_FALSE; 4056 } 4057 4058 4059 void Threads::add(JavaThread* p, bool force_daemon) { 4060 // The threads lock must be owned at this point 4061 assert_locked_or_safepoint(Threads_lock); 4062 4063 // See the comment for this method in thread.hpp for its purpose and 4064 // why it is called here. 4065 p->initialize_queues(); 4066 p->set_next(_thread_list); 4067 _thread_list = p; 4068 _number_of_threads++; 4069 oop threadObj = p->threadObj(); 4070 bool daemon = true; 4071 // Bootstrapping problem: threadObj can be null for initial 4072 // JavaThread (or for threads attached via JNI) 4073 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4074 _number_of_non_daemon_threads++; 4075 daemon = false; 4076 } 4077 4078 p->set_safepoint_visible(true); 4079 4080 ThreadService::add_thread(p, daemon); 4081 4082 // Possible GC point. 4083 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4084 } 4085 4086 void Threads::remove(JavaThread* p) { 4087 // Extra scope needed for Thread_lock, so we can check 4088 // that we do not remove thread without safepoint code notice 4089 { MutexLocker ml(Threads_lock); 4090 4091 assert(includes(p), "p must be present"); 4092 4093 JavaThread* current = _thread_list; 4094 JavaThread* prev = NULL; 4095 4096 while (current != p) { 4097 prev = current; 4098 current = current->next(); 4099 } 4100 4101 if (prev) { 4102 prev->set_next(current->next()); 4103 } else { 4104 _thread_list = p->next(); 4105 } 4106 _number_of_threads--; 4107 oop threadObj = p->threadObj(); 4108 bool daemon = true; 4109 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4110 _number_of_non_daemon_threads--; 4111 daemon = false; 4112 4113 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4114 // on destroy_vm will wake up. 4115 if (number_of_non_daemon_threads() == 1) 4116 Threads_lock->notify_all(); 4117 } 4118 ThreadService::remove_thread(p, daemon); 4119 4120 // Make sure that safepoint code disregard this thread. This is needed since 4121 // the thread might mess around with locks after this point. This can cause it 4122 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4123 // of this thread since it is removed from the queue. 4124 p->set_terminated_value(); 4125 4126 // Now, this thread is not visible to safepoint 4127 p->set_safepoint_visible(false); 4128 // once the thread becomes safepoint invisible, we can not use its per-thread 4129 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4130 // to release its per-thread recorder here. 4131 MemTracker::thread_exiting(p); 4132 } // unlock Threads_lock 4133 4134 // Since Events::log uses a lock, we grab it outside the Threads_lock 4135 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4136 } 4137 4138 // Threads_lock must be held when this is called (or must be called during a safepoint) 4139 bool Threads::includes(JavaThread* p) { 4140 assert(Threads_lock->is_locked(), "sanity check"); 4141 ALL_JAVA_THREADS(q) { 4142 if (q == p ) { 4143 return true; 4144 } 4145 } 4146 return false; 4147 } 4148 4149 // Operations on the Threads list for GC. These are not explicitly locked, 4150 // but the garbage collector must provide a safe context for them to run. 4151 // In particular, these things should never be called when the Threads_lock 4152 // is held by some other thread. (Note: the Safepoint abstraction also 4153 // uses the Threads_lock to gurantee this property. It also makes sure that 4154 // all threads gets blocked when exiting or starting). 4155 4156 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4157 ALL_JAVA_THREADS(p) { 4158 p->oops_do(f, cld_f, cf); 4159 } 4160 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4161 } 4162 4163 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4164 // Introduce a mechanism allowing parallel threads to claim threads as 4165 // root groups. Overhead should be small enough to use all the time, 4166 // even in sequential code. 4167 SharedHeap* sh = SharedHeap::heap(); 4168 // Cannot yet substitute active_workers for n_par_threads 4169 // because of G1CollectedHeap::verify() use of 4170 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4171 // turn off parallelism in process_strong_roots while active_workers 4172 // is being used for parallelism elsewhere. 4173 bool is_par = sh->n_par_threads() > 0; 4174 assert(!is_par || 4175 (SharedHeap::heap()->n_par_threads() == 4176 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4177 int cp = SharedHeap::heap()->strong_roots_parity(); 4178 ALL_JAVA_THREADS(p) { 4179 if (p->claim_oops_do(is_par, cp)) { 4180 p->oops_do(f, cld_f, cf); 4181 } 4182 } 4183 VMThread* vmt = VMThread::vm_thread(); 4184 if (vmt->claim_oops_do(is_par, cp)) { 4185 vmt->oops_do(f, cld_f, cf); 4186 } 4187 } 4188 4189 #if INCLUDE_ALL_GCS 4190 // Used by ParallelScavenge 4191 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4192 ALL_JAVA_THREADS(p) { 4193 q->enqueue(new ThreadRootsTask(p)); 4194 } 4195 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4196 } 4197 4198 // Used by Parallel Old 4199 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4200 ALL_JAVA_THREADS(p) { 4201 q->enqueue(new ThreadRootsMarkingTask(p)); 4202 } 4203 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4204 } 4205 #endif // INCLUDE_ALL_GCS 4206 4207 void Threads::nmethods_do(CodeBlobClosure* cf) { 4208 ALL_JAVA_THREADS(p) { 4209 p->nmethods_do(cf); 4210 } 4211 VMThread::vm_thread()->nmethods_do(cf); 4212 } 4213 4214 void Threads::metadata_do(void f(Metadata*)) { 4215 ALL_JAVA_THREADS(p) { 4216 p->metadata_do(f); 4217 } 4218 } 4219 4220 void Threads::gc_epilogue() { 4221 ALL_JAVA_THREADS(p) { 4222 p->gc_epilogue(); 4223 } 4224 } 4225 4226 void Threads::gc_prologue() { 4227 ALL_JAVA_THREADS(p) { 4228 p->gc_prologue(); 4229 } 4230 } 4231 4232 void Threads::deoptimized_wrt_marked_nmethods() { 4233 ALL_JAVA_THREADS(p) { 4234 p->deoptimized_wrt_marked_nmethods(); 4235 } 4236 } 4237 4238 4239 // Get count Java threads that are waiting to enter the specified monitor. 4240 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4241 address monitor, bool doLock) { 4242 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4243 "must grab Threads_lock or be at safepoint"); 4244 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4245 4246 int i = 0; 4247 { 4248 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4249 ALL_JAVA_THREADS(p) { 4250 if (p->is_Compiler_thread()) continue; 4251 4252 address pending = (address)p->current_pending_monitor(); 4253 if (pending == monitor) { // found a match 4254 if (i < count) result->append(p); // save the first count matches 4255 i++; 4256 } 4257 } 4258 } 4259 return result; 4260 } 4261 4262 4263 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4264 assert(doLock || 4265 Threads_lock->owned_by_self() || 4266 SafepointSynchronize::is_at_safepoint(), 4267 "must grab Threads_lock or be at safepoint"); 4268 4269 // NULL owner means not locked so we can skip the search 4270 if (owner == NULL) return NULL; 4271 4272 { 4273 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4274 ALL_JAVA_THREADS(p) { 4275 // first, see if owner is the address of a Java thread 4276 if (owner == (address)p) return p; 4277 } 4278 } 4279 // Cannot assert on lack of success here since this function may be 4280 // used by code that is trying to report useful problem information 4281 // like deadlock detection. 4282 if (UseHeavyMonitors) return NULL; 4283 4284 // 4285 // If we didn't find a matching Java thread and we didn't force use of 4286 // heavyweight monitors, then the owner is the stack address of the 4287 // Lock Word in the owning Java thread's stack. 4288 // 4289 JavaThread* the_owner = NULL; 4290 { 4291 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4292 ALL_JAVA_THREADS(q) { 4293 if (q->is_lock_owned(owner)) { 4294 the_owner = q; 4295 break; 4296 } 4297 } 4298 } 4299 // cannot assert on lack of success here; see above comment 4300 return the_owner; 4301 } 4302 4303 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4304 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4305 char buf[32]; 4306 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4307 4308 st->print_cr("Full thread dump %s (%s %s):", 4309 Abstract_VM_Version::vm_name(), 4310 Abstract_VM_Version::vm_release(), 4311 Abstract_VM_Version::vm_info_string() 4312 ); 4313 st->cr(); 4314 4315 #if INCLUDE_ALL_GCS 4316 // Dump concurrent locks 4317 ConcurrentLocksDump concurrent_locks; 4318 if (print_concurrent_locks) { 4319 concurrent_locks.dump_at_safepoint(); 4320 } 4321 #endif // INCLUDE_ALL_GCS 4322 4323 ALL_JAVA_THREADS(p) { 4324 ResourceMark rm; 4325 p->print_on(st); 4326 if (print_stacks) { 4327 if (internal_format) { 4328 p->trace_stack(); 4329 } else { 4330 p->print_stack_on(st); 4331 } 4332 } 4333 st->cr(); 4334 #if INCLUDE_ALL_GCS 4335 if (print_concurrent_locks) { 4336 concurrent_locks.print_locks_on(p, st); 4337 } 4338 #endif // INCLUDE_ALL_GCS 4339 } 4340 4341 VMThread::vm_thread()->print_on(st); 4342 st->cr(); 4343 Universe::heap()->print_gc_threads_on(st); 4344 WatcherThread* wt = WatcherThread::watcher_thread(); 4345 if (wt != NULL) { 4346 wt->print_on(st); 4347 st->cr(); 4348 } 4349 CompileBroker::print_compiler_threads_on(st); 4350 st->flush(); 4351 } 4352 4353 // Threads::print_on_error() is called by fatal error handler. It's possible 4354 // that VM is not at safepoint and/or current thread is inside signal handler. 4355 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4356 // memory (even in resource area), it might deadlock the error handler. 4357 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4358 bool found_current = false; 4359 st->print_cr("Java Threads: ( => current thread )"); 4360 ALL_JAVA_THREADS(thread) { 4361 bool is_current = (current == thread); 4362 found_current = found_current || is_current; 4363 4364 st->print("%s", is_current ? "=>" : " "); 4365 4366 st->print(PTR_FORMAT, thread); 4367 st->print(" "); 4368 thread->print_on_error(st, buf, buflen); 4369 st->cr(); 4370 } 4371 st->cr(); 4372 4373 st->print_cr("Other Threads:"); 4374 if (VMThread::vm_thread()) { 4375 bool is_current = (current == VMThread::vm_thread()); 4376 found_current = found_current || is_current; 4377 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4378 4379 st->print(PTR_FORMAT, VMThread::vm_thread()); 4380 st->print(" "); 4381 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4382 st->cr(); 4383 } 4384 WatcherThread* wt = WatcherThread::watcher_thread(); 4385 if (wt != NULL) { 4386 bool is_current = (current == wt); 4387 found_current = found_current || is_current; 4388 st->print("%s", is_current ? "=>" : " "); 4389 4390 st->print(PTR_FORMAT, wt); 4391 st->print(" "); 4392 wt->print_on_error(st, buf, buflen); 4393 st->cr(); 4394 } 4395 if (!found_current) { 4396 st->cr(); 4397 st->print("=>" PTR_FORMAT " (exited) ", current); 4398 current->print_on_error(st, buf, buflen); 4399 st->cr(); 4400 } 4401 } 4402 4403 // Internal SpinLock and Mutex 4404 // Based on ParkEvent 4405 4406 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4407 // 4408 // We employ SpinLocks _only for low-contention, fixed-length 4409 // short-duration critical sections where we're concerned 4410 // about native mutex_t or HotSpot Mutex:: latency. 4411 // The mux construct provides a spin-then-block mutual exclusion 4412 // mechanism. 4413 // 4414 // Testing has shown that contention on the ListLock guarding gFreeList 4415 // is common. If we implement ListLock as a simple SpinLock it's common 4416 // for the JVM to devolve to yielding with little progress. This is true 4417 // despite the fact that the critical sections protected by ListLock are 4418 // extremely short. 4419 // 4420 // TODO-FIXME: ListLock should be of type SpinLock. 4421 // We should make this a 1st-class type, integrated into the lock 4422 // hierarchy as leaf-locks. Critically, the SpinLock structure 4423 // should have sufficient padding to avoid false-sharing and excessive 4424 // cache-coherency traffic. 4425 4426 4427 typedef volatile int SpinLockT ; 4428 4429 void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4430 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4431 return ; // normal fast-path return 4432 } 4433 4434 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4435 TEVENT (SpinAcquire - ctx) ; 4436 int ctr = 0 ; 4437 int Yields = 0 ; 4438 for (;;) { 4439 while (*adr != 0) { 4440 ++ctr ; 4441 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4442 if (Yields > 5) { 4443 // Consider using a simple NakedSleep() instead. 4444 // Then SpinAcquire could be called by non-JVM threads 4445 Thread::current()->_ParkEvent->park(1) ; 4446 } else { 4447 os::NakedYield() ; 4448 ++Yields ; 4449 } 4450 } else { 4451 SpinPause() ; 4452 } 4453 } 4454 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4455 } 4456 } 4457 4458 void Thread::SpinRelease (volatile int * adr) { 4459 assert (*adr != 0, "invariant") ; 4460 OrderAccess::fence() ; // guarantee at least release consistency. 4461 // Roach-motel semantics. 4462 // It's safe if subsequent LDs and STs float "up" into the critical section, 4463 // but prior LDs and STs within the critical section can't be allowed 4464 // to reorder or float past the ST that releases the lock. 4465 *adr = 0 ; 4466 } 4467 4468 // muxAcquire and muxRelease: 4469 // 4470 // * muxAcquire and muxRelease support a single-word lock-word construct. 4471 // The LSB of the word is set IFF the lock is held. 4472 // The remainder of the word points to the head of a singly-linked list 4473 // of threads blocked on the lock. 4474 // 4475 // * The current implementation of muxAcquire-muxRelease uses its own 4476 // dedicated Thread._MuxEvent instance. If we're interested in 4477 // minimizing the peak number of extant ParkEvent instances then 4478 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4479 // as certain invariants were satisfied. Specifically, care would need 4480 // to be taken with regards to consuming unpark() "permits". 4481 // A safe rule of thumb is that a thread would never call muxAcquire() 4482 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4483 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4484 // consume an unpark() permit intended for monitorenter, for instance. 4485 // One way around this would be to widen the restricted-range semaphore 4486 // implemented in park(). Another alternative would be to provide 4487 // multiple instances of the PlatformEvent() for each thread. One 4488 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4489 // 4490 // * Usage: 4491 // -- Only as leaf locks 4492 // -- for short-term locking only as muxAcquire does not perform 4493 // thread state transitions. 4494 // 4495 // Alternatives: 4496 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4497 // but with parking or spin-then-park instead of pure spinning. 4498 // * Use Taura-Oyama-Yonenzawa locks. 4499 // * It's possible to construct a 1-0 lock if we encode the lockword as 4500 // (List,LockByte). Acquire will CAS the full lockword while Release 4501 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4502 // acquiring threads use timers (ParkTimed) to detect and recover from 4503 // the stranding window. Thread/Node structures must be aligned on 256-byte 4504 // boundaries by using placement-new. 4505 // * Augment MCS with advisory back-link fields maintained with CAS(). 4506 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4507 // The validity of the backlinks must be ratified before we trust the value. 4508 // If the backlinks are invalid the exiting thread must back-track through the 4509 // the forward links, which are always trustworthy. 4510 // * Add a successor indication. The LockWord is currently encoded as 4511 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4512 // to provide the usual futile-wakeup optimization. 4513 // See RTStt for details. 4514 // * Consider schedctl.sc_nopreempt to cover the critical section. 4515 // 4516 4517 4518 typedef volatile intptr_t MutexT ; // Mux Lock-word 4519 enum MuxBits { LOCKBIT = 1 } ; 4520 4521 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4522 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4523 if (w == 0) return ; 4524 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4525 return ; 4526 } 4527 4528 TEVENT (muxAcquire - Contention) ; 4529 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4530 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4531 for (;;) { 4532 int its = (os::is_MP() ? 100 : 0) + 1 ; 4533 4534 // Optional spin phase: spin-then-park strategy 4535 while (--its >= 0) { 4536 w = *Lock ; 4537 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4538 return ; 4539 } 4540 } 4541 4542 Self->reset() ; 4543 Self->OnList = intptr_t(Lock) ; 4544 // The following fence() isn't _strictly necessary as the subsequent 4545 // CAS() both serializes execution and ratifies the fetched *Lock value. 4546 OrderAccess::fence(); 4547 for (;;) { 4548 w = *Lock ; 4549 if ((w & LOCKBIT) == 0) { 4550 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4551 Self->OnList = 0 ; // hygiene - allows stronger asserts 4552 return ; 4553 } 4554 continue ; // Interference -- *Lock changed -- Just retry 4555 } 4556 assert (w & LOCKBIT, "invariant") ; 4557 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4558 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4559 } 4560 4561 while (Self->OnList != 0) { 4562 Self->park() ; 4563 } 4564 } 4565 } 4566 4567 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4568 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4569 if (w == 0) return ; 4570 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4571 return ; 4572 } 4573 4574 TEVENT (muxAcquire - Contention) ; 4575 ParkEvent * ReleaseAfter = NULL ; 4576 if (ev == NULL) { 4577 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4578 } 4579 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4580 for (;;) { 4581 guarantee (ev->OnList == 0, "invariant") ; 4582 int its = (os::is_MP() ? 100 : 0) + 1 ; 4583 4584 // Optional spin phase: spin-then-park strategy 4585 while (--its >= 0) { 4586 w = *Lock ; 4587 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4588 if (ReleaseAfter != NULL) { 4589 ParkEvent::Release (ReleaseAfter) ; 4590 } 4591 return ; 4592 } 4593 } 4594 4595 ev->reset() ; 4596 ev->OnList = intptr_t(Lock) ; 4597 // The following fence() isn't _strictly necessary as the subsequent 4598 // CAS() both serializes execution and ratifies the fetched *Lock value. 4599 OrderAccess::fence(); 4600 for (;;) { 4601 w = *Lock ; 4602 if ((w & LOCKBIT) == 0) { 4603 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4604 ev->OnList = 0 ; 4605 // We call ::Release while holding the outer lock, thus 4606 // artificially lengthening the critical section. 4607 // Consider deferring the ::Release() until the subsequent unlock(), 4608 // after we've dropped the outer lock. 4609 if (ReleaseAfter != NULL) { 4610 ParkEvent::Release (ReleaseAfter) ; 4611 } 4612 return ; 4613 } 4614 continue ; // Interference -- *Lock changed -- Just retry 4615 } 4616 assert (w & LOCKBIT, "invariant") ; 4617 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4618 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4619 } 4620 4621 while (ev->OnList != 0) { 4622 ev->park() ; 4623 } 4624 } 4625 } 4626 4627 // Release() must extract a successor from the list and then wake that thread. 4628 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4629 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4630 // Release() would : 4631 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4632 // (B) Extract a successor from the private list "in-hand" 4633 // (C) attempt to CAS() the residual back into *Lock over null. 4634 // If there were any newly arrived threads and the CAS() would fail. 4635 // In that case Release() would detach the RATs, re-merge the list in-hand 4636 // with the RATs and repeat as needed. Alternately, Release() might 4637 // detach and extract a successor, but then pass the residual list to the wakee. 4638 // The wakee would be responsible for reattaching and remerging before it 4639 // competed for the lock. 4640 // 4641 // Both "pop" and DMR are immune from ABA corruption -- there can be 4642 // multiple concurrent pushers, but only one popper or detacher. 4643 // This implementation pops from the head of the list. This is unfair, 4644 // but tends to provide excellent throughput as hot threads remain hot. 4645 // (We wake recently run threads first). 4646 4647 void Thread::muxRelease (volatile intptr_t * Lock) { 4648 for (;;) { 4649 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4650 assert (w & LOCKBIT, "invariant") ; 4651 if (w == LOCKBIT) return ; 4652 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4653 assert (List != NULL, "invariant") ; 4654 assert (List->OnList == intptr_t(Lock), "invariant") ; 4655 ParkEvent * nxt = List->ListNext ; 4656 4657 // The following CAS() releases the lock and pops the head element. 4658 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4659 continue ; 4660 } 4661 List->OnList = 0 ; 4662 OrderAccess::fence() ; 4663 List->unpark () ; 4664 return ; 4665 } 4666 } 4667 4668 4669 void Threads::verify() { 4670 ALL_JAVA_THREADS(p) { 4671 p->verify(); 4672 } 4673 VMThread* thread = VMThread::vm_thread(); 4674 if (thread != NULL) thread->verify(); 4675 }