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/aprofiler.hpp" 49 #include "runtime/arguments.hpp" 50 #include "runtime/biasedLocking.hpp" 51 #include "runtime/deoptimization.hpp" 52 #include "runtime/fprofiler.hpp" 53 #include "runtime/frame.inline.hpp" 54 #include "runtime/init.hpp" 55 #include "runtime/interfaceSupport.hpp" 56 #include "runtime/java.hpp" 57 #include "runtime/javaCalls.hpp" 58 #include "runtime/jniPeriodicChecker.hpp" 59 #include "runtime/memprofiler.hpp" 60 #include "runtime/mutexLocker.hpp" 61 #include "runtime/objectMonitor.hpp" 62 #include "runtime/osThread.hpp" 63 #include "runtime/safepoint.hpp" 64 #include "runtime/sharedRuntime.hpp" 65 #include "runtime/statSampler.hpp" 66 #include "runtime/stubRoutines.hpp" 67 #include "runtime/task.hpp" 68 #include "runtime/thread.inline.hpp" 69 #include "runtime/threadCritical.hpp" 70 #include "runtime/threadLocalStorage.hpp" 71 #include "runtime/vframe.hpp" 72 #include "runtime/vframeArray.hpp" 73 #include "runtime/vframe_hp.hpp" 74 #include "runtime/vmThread.hpp" 75 #include "runtime/vm_operations.hpp" 76 #include "services/attachListener.hpp" 77 #include "services/management.hpp" 78 #include "services/memTracker.hpp" 79 #include "services/threadService.hpp" 80 #include "trace/tracing.hpp" 81 #include "trace/traceMacros.hpp" 82 #include "utilities/defaultStream.hpp" 83 #include "utilities/dtrace.hpp" 84 #include "utilities/events.hpp" 85 #include "utilities/preserveException.hpp" 86 #include "utilities/macros.hpp" 87 #ifdef TARGET_OS_FAMILY_linux 88 # include "os_linux.inline.hpp" 89 #endif 90 #ifdef TARGET_OS_FAMILY_solaris 91 # include "os_solaris.inline.hpp" 92 #endif 93 #ifdef TARGET_OS_FAMILY_windows 94 # include "os_windows.inline.hpp" 95 #endif 96 #ifdef TARGET_OS_FAMILY_bsd 97 # include "os_bsd.inline.hpp" 98 #endif 99 #if INCLUDE_ALL_GCS 100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 102 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 103 #endif // INCLUDE_ALL_GCS 104 #ifdef COMPILER1 105 #include "c1/c1_Compiler.hpp" 106 #endif 107 #ifdef COMPILER2 108 #include "opto/c2compiler.hpp" 109 #include "opto/idealGraphPrinter.hpp" 110 #endif 111 112 #ifdef DTRACE_ENABLED 113 114 // Only bother with this argument setup if dtrace is available 115 116 #ifndef USDT2 117 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 118 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 119 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 120 intptr_t, intptr_t, bool); 121 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 122 intptr_t, intptr_t, bool); 123 124 #define DTRACE_THREAD_PROBE(probe, javathread) \ 125 { \ 126 ResourceMark rm(this); \ 127 int len = 0; \ 128 const char* name = (javathread)->get_thread_name(); \ 129 len = strlen(name); \ 130 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 131 name, len, \ 132 java_lang_Thread::thread_id((javathread)->threadObj()), \ 133 (javathread)->osthread()->thread_id(), \ 134 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 135 } 136 137 #else /* USDT2 */ 138 139 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START 140 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP 141 142 #define DTRACE_THREAD_PROBE(probe, javathread) \ 143 { \ 144 ResourceMark rm(this); \ 145 int len = 0; \ 146 const char* name = (javathread)->get_thread_name(); \ 147 len = strlen(name); \ 148 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 149 (char *) name, len, \ 150 java_lang_Thread::thread_id((javathread)->threadObj()), \ 151 (uintptr_t) (javathread)->osthread()->thread_id(), \ 152 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 153 } 154 155 #endif /* USDT2 */ 156 157 #else // ndef DTRACE_ENABLED 158 159 #define DTRACE_THREAD_PROBE(probe, javathread) 160 161 #endif // ndef DTRACE_ENABLED 162 163 164 // Class hierarchy 165 // - Thread 166 // - VMThread 167 // - WatcherThread 168 // - ConcurrentMarkSweepThread 169 // - JavaThread 170 // - CompilerThread 171 172 // ======= Thread ======== 173 // Support for forcing alignment of thread objects for biased locking 174 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 175 if (UseBiasedLocking) { 176 const int alignment = markOopDesc::biased_lock_alignment; 177 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 178 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 179 : AllocateHeap(aligned_size, flags, CURRENT_PC, 180 AllocFailStrategy::RETURN_NULL); 181 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 182 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 183 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 184 "JavaThread alignment code overflowed allocated storage"); 185 if (TraceBiasedLocking) { 186 if (aligned_addr != real_malloc_addr) 187 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 188 real_malloc_addr, aligned_addr); 189 } 190 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 191 return aligned_addr; 192 } else { 193 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 194 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 195 } 196 } 197 198 void Thread::operator delete(void* p) { 199 if (UseBiasedLocking) { 200 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 201 FreeHeap(real_malloc_addr, mtThread); 202 } else { 203 FreeHeap(p, mtThread); 204 } 205 } 206 207 208 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 209 // JavaThread 210 211 212 Thread::Thread() { 213 // stack and get_thread 214 set_stack_base(NULL); 215 set_stack_size(0); 216 set_self_raw_id(0); 217 set_lgrp_id(-1); 218 219 // allocated data structures 220 set_osthread(NULL); 221 set_resource_area(new (mtThread)ResourceArea()); 222 set_handle_area(new (mtThread) HandleArea(NULL)); 223 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(300, 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 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 958 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 959 // used for compilation in the future. If that change is made, the need for these methods 960 // should be revisited, and they should be removed if possible. 961 962 bool Thread::is_lock_owned(address adr) const { 963 return on_local_stack(adr); 964 } 965 966 bool Thread::set_as_starting_thread() { 967 // NOTE: this must be called inside the main thread. 968 return os::create_main_thread((JavaThread*)this); 969 } 970 971 static void initialize_class(Symbol* class_name, TRAPS) { 972 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 973 InstanceKlass::cast(klass)->initialize(CHECK); 974 } 975 976 977 // Creates the initial ThreadGroup 978 static Handle create_initial_thread_group(TRAPS) { 979 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 980 instanceKlassHandle klass (THREAD, k); 981 982 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 983 { 984 JavaValue result(T_VOID); 985 JavaCalls::call_special(&result, 986 system_instance, 987 klass, 988 vmSymbols::object_initializer_name(), 989 vmSymbols::void_method_signature(), 990 CHECK_NH); 991 } 992 Universe::set_system_thread_group(system_instance()); 993 994 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 995 { 996 JavaValue result(T_VOID); 997 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 998 JavaCalls::call_special(&result, 999 main_instance, 1000 klass, 1001 vmSymbols::object_initializer_name(), 1002 vmSymbols::threadgroup_string_void_signature(), 1003 system_instance, 1004 string, 1005 CHECK_NH); 1006 } 1007 return main_instance; 1008 } 1009 1010 // Creates the initial Thread 1011 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1012 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1013 instanceKlassHandle klass (THREAD, k); 1014 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1015 1016 java_lang_Thread::set_thread(thread_oop(), thread); 1017 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1018 thread->set_threadObj(thread_oop()); 1019 1020 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1021 1022 JavaValue result(T_VOID); 1023 JavaCalls::call_special(&result, thread_oop, 1024 klass, 1025 vmSymbols::object_initializer_name(), 1026 vmSymbols::threadgroup_string_void_signature(), 1027 thread_group, 1028 string, 1029 CHECK_NULL); 1030 return thread_oop(); 1031 } 1032 1033 static void call_initializeSystemClass(TRAPS) { 1034 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1035 instanceKlassHandle klass (THREAD, k); 1036 1037 JavaValue result(T_VOID); 1038 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1039 vmSymbols::void_method_signature(), CHECK); 1040 } 1041 1042 char java_runtime_name[128] = ""; 1043 char java_runtime_version[128] = ""; 1044 1045 // extract the JRE name from sun.misc.Version.java_runtime_name 1046 static const char* get_java_runtime_name(TRAPS) { 1047 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1048 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1049 fieldDescriptor fd; 1050 bool found = k != NULL && 1051 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1052 vmSymbols::string_signature(), &fd); 1053 if (found) { 1054 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1055 if (name_oop == NULL) 1056 return NULL; 1057 const char* name = java_lang_String::as_utf8_string(name_oop, 1058 java_runtime_name, 1059 sizeof(java_runtime_name)); 1060 return name; 1061 } else { 1062 return NULL; 1063 } 1064 } 1065 1066 // extract the JRE version from sun.misc.Version.java_runtime_version 1067 static const char* get_java_runtime_version(TRAPS) { 1068 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1069 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1070 fieldDescriptor fd; 1071 bool found = k != NULL && 1072 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1073 vmSymbols::string_signature(), &fd); 1074 if (found) { 1075 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1076 if (name_oop == NULL) 1077 return NULL; 1078 const char* name = java_lang_String::as_utf8_string(name_oop, 1079 java_runtime_version, 1080 sizeof(java_runtime_version)); 1081 return name; 1082 } else { 1083 return NULL; 1084 } 1085 } 1086 1087 // General purpose hook into Java code, run once when the VM is initialized. 1088 // The Java library method itself may be changed independently from the VM. 1089 static void call_postVMInitHook(TRAPS) { 1090 Klass* k = SystemDictionary::PostVMInitHook_klass(); 1091 instanceKlassHandle klass (THREAD, k); 1092 if (klass.not_null()) { 1093 JavaValue result(T_VOID); 1094 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1095 vmSymbols::void_method_signature(), 1096 CHECK); 1097 } 1098 } 1099 1100 static void reset_vm_info_property(TRAPS) { 1101 // the vm info string 1102 ResourceMark rm(THREAD); 1103 const char *vm_info = VM_Version::vm_info_string(); 1104 1105 // java.lang.System class 1106 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1107 instanceKlassHandle klass (THREAD, k); 1108 1109 // setProperty arguments 1110 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1111 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1112 1113 // return value 1114 JavaValue r(T_OBJECT); 1115 1116 // public static String setProperty(String key, String value); 1117 JavaCalls::call_static(&r, 1118 klass, 1119 vmSymbols::setProperty_name(), 1120 vmSymbols::string_string_string_signature(), 1121 key_str, 1122 value_str, 1123 CHECK); 1124 } 1125 1126 1127 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1128 assert(thread_group.not_null(), "thread group should be specified"); 1129 assert(threadObj() == NULL, "should only create Java thread object once"); 1130 1131 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1132 instanceKlassHandle klass (THREAD, k); 1133 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1134 1135 java_lang_Thread::set_thread(thread_oop(), this); 1136 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1137 set_threadObj(thread_oop()); 1138 1139 JavaValue result(T_VOID); 1140 if (thread_name != NULL) { 1141 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1142 // Thread gets assigned specified name and null target 1143 JavaCalls::call_special(&result, 1144 thread_oop, 1145 klass, 1146 vmSymbols::object_initializer_name(), 1147 vmSymbols::threadgroup_string_void_signature(), 1148 thread_group, // Argument 1 1149 name, // Argument 2 1150 THREAD); 1151 } else { 1152 // Thread gets assigned name "Thread-nnn" and null target 1153 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1154 JavaCalls::call_special(&result, 1155 thread_oop, 1156 klass, 1157 vmSymbols::object_initializer_name(), 1158 vmSymbols::threadgroup_runnable_void_signature(), 1159 thread_group, // Argument 1 1160 Handle(), // Argument 2 1161 THREAD); 1162 } 1163 1164 1165 if (daemon) { 1166 java_lang_Thread::set_daemon(thread_oop()); 1167 } 1168 1169 if (HAS_PENDING_EXCEPTION) { 1170 return; 1171 } 1172 1173 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1174 Handle threadObj(this, this->threadObj()); 1175 1176 JavaCalls::call_special(&result, 1177 thread_group, 1178 group, 1179 vmSymbols::add_method_name(), 1180 vmSymbols::thread_void_signature(), 1181 threadObj, // Arg 1 1182 THREAD); 1183 1184 1185 } 1186 1187 // NamedThread -- non-JavaThread subclasses with multiple 1188 // uniquely named instances should derive from this. 1189 NamedThread::NamedThread() : Thread() { 1190 _name = NULL; 1191 _processed_thread = NULL; 1192 } 1193 1194 NamedThread::~NamedThread() { 1195 if (_name != NULL) { 1196 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1197 _name = NULL; 1198 } 1199 } 1200 1201 void NamedThread::set_name(const char* format, ...) { 1202 guarantee(_name == NULL, "Only get to set name once."); 1203 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1204 guarantee(_name != NULL, "alloc failure"); 1205 va_list ap; 1206 va_start(ap, format); 1207 jio_vsnprintf(_name, max_name_len, format, ap); 1208 va_end(ap); 1209 } 1210 1211 // ======= WatcherThread ======== 1212 1213 // The watcher thread exists to simulate timer interrupts. It should 1214 // be replaced by an abstraction over whatever native support for 1215 // timer interrupts exists on the platform. 1216 1217 WatcherThread* WatcherThread::_watcher_thread = NULL; 1218 bool WatcherThread::_startable = false; 1219 volatile bool WatcherThread::_should_terminate = false; 1220 1221 WatcherThread::WatcherThread() : Thread() { 1222 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1223 if (os::create_thread(this, os::watcher_thread)) { 1224 _watcher_thread = this; 1225 1226 // Set the watcher thread to the highest OS priority which should not be 1227 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1228 // is created. The only normal thread using this priority is the reference 1229 // handler thread, which runs for very short intervals only. 1230 // If the VMThread's priority is not lower than the WatcherThread profiling 1231 // will be inaccurate. 1232 os::set_priority(this, MaxPriority); 1233 if (!DisableStartThread) { 1234 os::start_thread(this); 1235 } 1236 } 1237 } 1238 1239 int WatcherThread::sleep() const { 1240 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1241 1242 // remaining will be zero if there are no tasks, 1243 // causing the WatcherThread to sleep until a task is 1244 // enrolled 1245 int remaining = PeriodicTask::time_to_wait(); 1246 int time_slept = 0; 1247 1248 // we expect this to timeout - we only ever get unparked when 1249 // we should terminate or when a new task has been enrolled 1250 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1251 1252 jlong time_before_loop = os::javaTimeNanos(); 1253 1254 for (;;) { 1255 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1256 jlong now = os::javaTimeNanos(); 1257 1258 if (remaining == 0) { 1259 // if we didn't have any tasks we could have waited for a long time 1260 // consider the time_slept zero and reset time_before_loop 1261 time_slept = 0; 1262 time_before_loop = now; 1263 } else { 1264 // need to recalulate since we might have new tasks in _tasks 1265 time_slept = (int) ((now - time_before_loop) / 1000000); 1266 } 1267 1268 // Change to task list or spurious wakeup of some kind 1269 if (timedout || _should_terminate) { 1270 break; 1271 } 1272 1273 remaining = PeriodicTask::time_to_wait(); 1274 if (remaining == 0) { 1275 // Last task was just disenrolled so loop around and wait until 1276 // another task gets enrolled 1277 continue; 1278 } 1279 1280 remaining -= time_slept; 1281 if (remaining <= 0) 1282 break; 1283 } 1284 1285 return time_slept; 1286 } 1287 1288 void WatcherThread::run() { 1289 assert(this == watcher_thread(), "just checking"); 1290 1291 this->record_stack_base_and_size(); 1292 this->initialize_thread_local_storage(); 1293 this->set_active_handles(JNIHandleBlock::allocate_block()); 1294 while(!_should_terminate) { 1295 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1296 assert(watcher_thread() == this, "thread consistency check"); 1297 1298 // Calculate how long it'll be until the next PeriodicTask work 1299 // should be done, and sleep that amount of time. 1300 int time_waited = sleep(); 1301 1302 if (is_error_reported()) { 1303 // A fatal error has happened, the error handler(VMError::report_and_die) 1304 // should abort JVM after creating an error log file. However in some 1305 // rare cases, the error handler itself might deadlock. Here we try to 1306 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1307 // 1308 // This code is in WatcherThread because WatcherThread wakes up 1309 // periodically so the fatal error handler doesn't need to do anything; 1310 // also because the WatcherThread is less likely to crash than other 1311 // threads. 1312 1313 for (;;) { 1314 if (!ShowMessageBoxOnError 1315 && (OnError == NULL || OnError[0] == '\0') 1316 && Arguments::abort_hook() == NULL) { 1317 os::sleep(this, 2 * 60 * 1000, false); 1318 fdStream err(defaultStream::output_fd()); 1319 err.print_raw_cr("# [ timer expired, abort... ]"); 1320 // skip atexit/vm_exit/vm_abort hooks 1321 os::die(); 1322 } 1323 1324 // Wake up 5 seconds later, the fatal handler may reset OnError or 1325 // ShowMessageBoxOnError when it is ready to abort. 1326 os::sleep(this, 5 * 1000, false); 1327 } 1328 } 1329 1330 PeriodicTask::real_time_tick(time_waited); 1331 } 1332 1333 // Signal that it is terminated 1334 { 1335 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1336 _watcher_thread = NULL; 1337 Terminator_lock->notify(); 1338 } 1339 1340 // Thread destructor usually does this.. 1341 ThreadLocalStorage::set_thread(NULL); 1342 } 1343 1344 void WatcherThread::start() { 1345 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1346 1347 if (watcher_thread() == NULL && _startable) { 1348 _should_terminate = false; 1349 // Create the single instance of WatcherThread 1350 new WatcherThread(); 1351 } 1352 } 1353 1354 void WatcherThread::make_startable() { 1355 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1356 _startable = true; 1357 } 1358 1359 void WatcherThread::stop() { 1360 { 1361 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1362 _should_terminate = true; 1363 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1364 1365 WatcherThread* watcher = watcher_thread(); 1366 if (watcher != NULL) 1367 watcher->unpark(); 1368 } 1369 1370 // it is ok to take late safepoints here, if needed 1371 MutexLocker mu(Terminator_lock); 1372 1373 while(watcher_thread() != NULL) { 1374 // This wait should make safepoint checks, wait without a timeout, 1375 // and wait as a suspend-equivalent condition. 1376 // 1377 // Note: If the FlatProfiler is running, then this thread is waiting 1378 // for the WatcherThread to terminate and the WatcherThread, via the 1379 // FlatProfiler task, is waiting for the external suspend request on 1380 // this thread to complete. wait_for_ext_suspend_completion() will 1381 // eventually timeout, but that takes time. Making this wait a 1382 // suspend-equivalent condition solves that timeout problem. 1383 // 1384 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1385 Mutex::_as_suspend_equivalent_flag); 1386 } 1387 } 1388 1389 void WatcherThread::unpark() { 1390 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1391 PeriodicTask_lock->notify(); 1392 } 1393 1394 void WatcherThread::print_on(outputStream* st) const { 1395 st->print("\"%s\" ", name()); 1396 Thread::print_on(st); 1397 st->cr(); 1398 } 1399 1400 // ======= JavaThread ======== 1401 1402 // A JavaThread is a normal Java thread 1403 1404 void JavaThread::initialize() { 1405 // Initialize fields 1406 1407 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1408 set_claimed_par_id(-1); 1409 1410 set_saved_exception_pc(NULL); 1411 set_threadObj(NULL); 1412 _anchor.clear(); 1413 set_entry_point(NULL); 1414 set_jni_functions(jni_functions()); 1415 set_callee_target(NULL); 1416 set_vm_result(NULL); 1417 set_vm_result_2(NULL); 1418 set_vframe_array_head(NULL); 1419 set_vframe_array_last(NULL); 1420 set_deferred_locals(NULL); 1421 set_deopt_mark(NULL); 1422 set_deopt_nmethod(NULL); 1423 clear_must_deopt_id(); 1424 set_monitor_chunks(NULL); 1425 set_next(NULL); 1426 set_thread_state(_thread_new); 1427 #if INCLUDE_NMT 1428 set_recorder(NULL); 1429 #endif 1430 _terminated = _not_terminated; 1431 _privileged_stack_top = NULL; 1432 _array_for_gc = NULL; 1433 _suspend_equivalent = false; 1434 _in_deopt_handler = 0; 1435 _doing_unsafe_access = false; 1436 _stack_guard_state = stack_guard_unused; 1437 _exception_oop = NULL; 1438 _exception_pc = 0; 1439 _exception_handler_pc = 0; 1440 _is_method_handle_return = 0; 1441 _jvmti_thread_state= NULL; 1442 _should_post_on_exceptions_flag = JNI_FALSE; 1443 _jvmti_get_loaded_classes_closure = NULL; 1444 _interp_only_mode = 0; 1445 _special_runtime_exit_condition = _no_async_condition; 1446 _pending_async_exception = NULL; 1447 _is_compiling = false; 1448 _thread_stat = NULL; 1449 _thread_stat = new ThreadStatistics(); 1450 _blocked_on_compilation = false; 1451 _jni_active_critical = 0; 1452 _do_not_unlock_if_synchronized = false; 1453 _cached_monitor_info = NULL; 1454 _parker = Parker::Allocate(this) ; 1455 1456 #ifndef PRODUCT 1457 _jmp_ring_index = 0; 1458 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1459 record_jump(NULL, NULL, NULL, 0); 1460 } 1461 #endif /* PRODUCT */ 1462 1463 set_thread_profiler(NULL); 1464 if (FlatProfiler::is_active()) { 1465 // This is where we would decide to either give each thread it's own profiler 1466 // or use one global one from FlatProfiler, 1467 // or up to some count of the number of profiled threads, etc. 1468 ThreadProfiler* pp = new ThreadProfiler(); 1469 pp->engage(); 1470 set_thread_profiler(pp); 1471 } 1472 1473 // Setup safepoint state info for this thread 1474 ThreadSafepointState::create(this); 1475 1476 debug_only(_java_call_counter = 0); 1477 1478 // JVMTI PopFrame support 1479 _popframe_condition = popframe_inactive; 1480 _popframe_preserved_args = NULL; 1481 _popframe_preserved_args_size = 0; 1482 1483 pd_initialize(); 1484 } 1485 1486 #if INCLUDE_ALL_GCS 1487 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1488 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1489 #endif // INCLUDE_ALL_GCS 1490 1491 JavaThread::JavaThread(bool is_attaching_via_jni) : 1492 Thread() 1493 #if INCLUDE_ALL_GCS 1494 , _satb_mark_queue(&_satb_mark_queue_set), 1495 _dirty_card_queue(&_dirty_card_queue_set) 1496 #endif // INCLUDE_ALL_GCS 1497 { 1498 initialize(); 1499 if (is_attaching_via_jni) { 1500 _jni_attach_state = _attaching_via_jni; 1501 } else { 1502 _jni_attach_state = _not_attaching_via_jni; 1503 } 1504 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1505 _safepoint_visible = false; 1506 } 1507 1508 bool JavaThread::reguard_stack(address cur_sp) { 1509 if (_stack_guard_state != stack_guard_yellow_disabled) { 1510 return true; // Stack already guarded or guard pages not needed. 1511 } 1512 1513 if (register_stack_overflow()) { 1514 // For those architectures which have separate register and 1515 // memory stacks, we must check the register stack to see if 1516 // it has overflowed. 1517 return false; 1518 } 1519 1520 // Java code never executes within the yellow zone: the latter is only 1521 // there to provoke an exception during stack banging. If java code 1522 // is executing there, either StackShadowPages should be larger, or 1523 // some exception code in c1, c2 or the interpreter isn't unwinding 1524 // when it should. 1525 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1526 1527 enable_stack_yellow_zone(); 1528 return true; 1529 } 1530 1531 bool JavaThread::reguard_stack(void) { 1532 return reguard_stack(os::current_stack_pointer()); 1533 } 1534 1535 1536 void JavaThread::block_if_vm_exited() { 1537 if (_terminated == _vm_exited) { 1538 // _vm_exited is set at safepoint, and Threads_lock is never released 1539 // we will block here forever 1540 Threads_lock->lock_without_safepoint_check(); 1541 ShouldNotReachHere(); 1542 } 1543 } 1544 1545 1546 // Remove this ifdef when C1 is ported to the compiler interface. 1547 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1548 1549 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1550 Thread() 1551 #if INCLUDE_ALL_GCS 1552 , _satb_mark_queue(&_satb_mark_queue_set), 1553 _dirty_card_queue(&_dirty_card_queue_set) 1554 #endif // INCLUDE_ALL_GCS 1555 { 1556 if (TraceThreadEvents) { 1557 tty->print_cr("creating thread %p", this); 1558 } 1559 initialize(); 1560 _jni_attach_state = _not_attaching_via_jni; 1561 set_entry_point(entry_point); 1562 // Create the native thread itself. 1563 // %note runtime_23 1564 os::ThreadType thr_type = os::java_thread; 1565 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1566 os::java_thread; 1567 os::create_thread(this, thr_type, stack_sz); 1568 _safepoint_visible = false; 1569 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1570 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1571 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1572 // the exception consists of creating the exception object & initializing it, initialization 1573 // will leave the VM via a JavaCall and then all locks must be unlocked). 1574 // 1575 // The thread is still suspended when we reach here. Thread must be explicit started 1576 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1577 // by calling Threads:add. The reason why this is not done here, is because the thread 1578 // object must be fully initialized (take a look at JVM_Start) 1579 } 1580 1581 JavaThread::~JavaThread() { 1582 if (TraceThreadEvents) { 1583 tty->print_cr("terminate thread %p", this); 1584 } 1585 1586 // By now, this thread should already be invisible to safepoint, 1587 // and its per-thread recorder also collected. 1588 assert(!is_safepoint_visible(), "wrong state"); 1589 #if INCLUDE_NMT 1590 assert(get_recorder() == NULL, "Already collected"); 1591 #endif // INCLUDE_NMT 1592 1593 // JSR166 -- return the parker to the free list 1594 Parker::Release(_parker); 1595 _parker = NULL ; 1596 1597 // Free any remaining previous UnrollBlock 1598 vframeArray* old_array = vframe_array_last(); 1599 1600 if (old_array != NULL) { 1601 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1602 old_array->set_unroll_block(NULL); 1603 delete old_info; 1604 delete old_array; 1605 } 1606 1607 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1608 if (deferred != NULL) { 1609 // This can only happen if thread is destroyed before deoptimization occurs. 1610 assert(deferred->length() != 0, "empty array!"); 1611 do { 1612 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1613 deferred->remove_at(0); 1614 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1615 delete dlv; 1616 } while (deferred->length() != 0); 1617 delete deferred; 1618 } 1619 1620 // All Java related clean up happens in exit 1621 ThreadSafepointState::destroy(this); 1622 if (_thread_profiler != NULL) delete _thread_profiler; 1623 if (_thread_stat != NULL) delete _thread_stat; 1624 } 1625 1626 1627 // The first routine called by a new Java thread 1628 void JavaThread::run() { 1629 // initialize thread-local alloc buffer related fields 1630 this->initialize_tlab(); 1631 1632 // used to test validitity of stack trace backs 1633 this->record_base_of_stack_pointer(); 1634 1635 // Record real stack base and size. 1636 this->record_stack_base_and_size(); 1637 1638 // Initialize thread local storage; set before calling MutexLocker 1639 this->initialize_thread_local_storage(); 1640 1641 this->create_stack_guard_pages(); 1642 1643 this->cache_global_variables(); 1644 1645 // Thread is now sufficient initialized to be handled by the safepoint code as being 1646 // in the VM. Change thread state from _thread_new to _thread_in_vm 1647 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1648 1649 assert(JavaThread::current() == this, "sanity check"); 1650 assert(!Thread::current()->owns_locks(), "sanity check"); 1651 1652 DTRACE_THREAD_PROBE(start, this); 1653 1654 // This operation might block. We call that after all safepoint checks for a new thread has 1655 // been completed. 1656 this->set_active_handles(JNIHandleBlock::allocate_block()); 1657 1658 if (JvmtiExport::should_post_thread_life()) { 1659 JvmtiExport::post_thread_start(this); 1660 } 1661 1662 EventThreadStart event; 1663 if (event.should_commit()) { 1664 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1665 event.commit(); 1666 } 1667 1668 // We call another function to do the rest so we are sure that the stack addresses used 1669 // from there will be lower than the stack base just computed 1670 thread_main_inner(); 1671 1672 // Note, thread is no longer valid at this point! 1673 } 1674 1675 1676 void JavaThread::thread_main_inner() { 1677 assert(JavaThread::current() == this, "sanity check"); 1678 assert(this->threadObj() != NULL, "just checking"); 1679 1680 // Execute thread entry point unless this thread has a pending exception 1681 // or has been stopped before starting. 1682 // Note: Due to JVM_StopThread we can have pending exceptions already! 1683 if (!this->has_pending_exception() && 1684 !java_lang_Thread::is_stillborn(this->threadObj())) { 1685 { 1686 ResourceMark rm(this); 1687 this->set_native_thread_name(this->get_thread_name()); 1688 } 1689 HandleMark hm(this); 1690 this->entry_point()(this, this); 1691 } 1692 1693 DTRACE_THREAD_PROBE(stop, this); 1694 1695 this->exit(false); 1696 delete this; 1697 } 1698 1699 1700 static void ensure_join(JavaThread* thread) { 1701 // We do not need to grap the Threads_lock, since we are operating on ourself. 1702 Handle threadObj(thread, thread->threadObj()); 1703 assert(threadObj.not_null(), "java thread object must exist"); 1704 ObjectLocker lock(threadObj, thread); 1705 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1706 thread->clear_pending_exception(); 1707 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1708 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1709 // Clear the native thread instance - this makes isAlive return false and allows the join() 1710 // to complete once we've done the notify_all below 1711 java_lang_Thread::set_thread(threadObj(), NULL); 1712 lock.notify_all(thread); 1713 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1714 thread->clear_pending_exception(); 1715 } 1716 1717 1718 // For any new cleanup additions, please check to see if they need to be applied to 1719 // cleanup_failed_attach_current_thread as well. 1720 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1721 assert(this == JavaThread::current(), "thread consistency check"); 1722 1723 HandleMark hm(this); 1724 Handle uncaught_exception(this, this->pending_exception()); 1725 this->clear_pending_exception(); 1726 Handle threadObj(this, this->threadObj()); 1727 assert(threadObj.not_null(), "Java thread object should be created"); 1728 1729 if (get_thread_profiler() != NULL) { 1730 get_thread_profiler()->disengage(); 1731 ResourceMark rm; 1732 get_thread_profiler()->print(get_thread_name()); 1733 } 1734 1735 1736 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1737 { 1738 EXCEPTION_MARK; 1739 1740 CLEAR_PENDING_EXCEPTION; 1741 } 1742 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1743 // has to be fixed by a runtime query method 1744 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1745 // JSR-166: change call from from ThreadGroup.uncaughtException to 1746 // java.lang.Thread.dispatchUncaughtException 1747 if (uncaught_exception.not_null()) { 1748 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1749 { 1750 EXCEPTION_MARK; 1751 // Check if the method Thread.dispatchUncaughtException() exists. If so 1752 // call it. Otherwise we have an older library without the JSR-166 changes, 1753 // so call ThreadGroup.uncaughtException() 1754 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1755 CallInfo callinfo; 1756 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1757 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1758 vmSymbols::dispatchUncaughtException_name(), 1759 vmSymbols::throwable_void_signature(), 1760 KlassHandle(), false, false, THREAD); 1761 CLEAR_PENDING_EXCEPTION; 1762 methodHandle method = callinfo.selected_method(); 1763 if (method.not_null()) { 1764 JavaValue result(T_VOID); 1765 JavaCalls::call_virtual(&result, 1766 threadObj, thread_klass, 1767 vmSymbols::dispatchUncaughtException_name(), 1768 vmSymbols::throwable_void_signature(), 1769 uncaught_exception, 1770 THREAD); 1771 } else { 1772 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1773 JavaValue result(T_VOID); 1774 JavaCalls::call_virtual(&result, 1775 group, thread_group, 1776 vmSymbols::uncaughtException_name(), 1777 vmSymbols::thread_throwable_void_signature(), 1778 threadObj, // Arg 1 1779 uncaught_exception, // Arg 2 1780 THREAD); 1781 } 1782 if (HAS_PENDING_EXCEPTION) { 1783 ResourceMark rm(this); 1784 jio_fprintf(defaultStream::error_stream(), 1785 "\nException: %s thrown from the UncaughtExceptionHandler" 1786 " in thread \"%s\"\n", 1787 pending_exception()->klass()->external_name(), 1788 get_thread_name()); 1789 CLEAR_PENDING_EXCEPTION; 1790 } 1791 } 1792 } 1793 1794 // Called before the java thread exit since we want to read info 1795 // from java_lang_Thread object 1796 EventThreadEnd event; 1797 if (event.should_commit()) { 1798 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1799 event.commit(); 1800 } 1801 1802 // Call after last event on thread 1803 EVENT_THREAD_EXIT(this); 1804 1805 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1806 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1807 // is deprecated anyhow. 1808 { int count = 3; 1809 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1810 EXCEPTION_MARK; 1811 JavaValue result(T_VOID); 1812 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1813 JavaCalls::call_virtual(&result, 1814 threadObj, thread_klass, 1815 vmSymbols::exit_method_name(), 1816 vmSymbols::void_method_signature(), 1817 THREAD); 1818 CLEAR_PENDING_EXCEPTION; 1819 } 1820 } 1821 1822 // notify JVMTI 1823 if (JvmtiExport::should_post_thread_life()) { 1824 JvmtiExport::post_thread_end(this); 1825 } 1826 1827 // We have notified the agents that we are exiting, before we go on, 1828 // we must check for a pending external suspend request and honor it 1829 // in order to not surprise the thread that made the suspend request. 1830 while (true) { 1831 { 1832 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1833 if (!is_external_suspend()) { 1834 set_terminated(_thread_exiting); 1835 ThreadService::current_thread_exiting(this); 1836 break; 1837 } 1838 // Implied else: 1839 // Things get a little tricky here. We have a pending external 1840 // suspend request, but we are holding the SR_lock so we 1841 // can't just self-suspend. So we temporarily drop the lock 1842 // and then self-suspend. 1843 } 1844 1845 ThreadBlockInVM tbivm(this); 1846 java_suspend_self(); 1847 1848 // We're done with this suspend request, but we have to loop around 1849 // and check again. Eventually we will get SR_lock without a pending 1850 // external suspend request and will be able to mark ourselves as 1851 // exiting. 1852 } 1853 // no more external suspends are allowed at this point 1854 } else { 1855 // before_exit() has already posted JVMTI THREAD_END events 1856 } 1857 1858 // Notify waiters on thread object. This has to be done after exit() is called 1859 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1860 // group should have the destroyed bit set before waiters are notified). 1861 ensure_join(this); 1862 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1863 1864 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1865 // held by this thread must be released. A detach operation must only 1866 // get here if there are no Java frames on the stack. Therefore, any 1867 // owned monitors at this point MUST be JNI-acquired monitors which are 1868 // pre-inflated and in the monitor cache. 1869 // 1870 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1871 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1872 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1873 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1874 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1875 } 1876 1877 // These things needs to be done while we are still a Java Thread. Make sure that thread 1878 // is in a consistent state, in case GC happens 1879 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1880 1881 if (active_handles() != NULL) { 1882 JNIHandleBlock* block = active_handles(); 1883 set_active_handles(NULL); 1884 JNIHandleBlock::release_block(block); 1885 } 1886 1887 if (free_handle_block() != NULL) { 1888 JNIHandleBlock* block = free_handle_block(); 1889 set_free_handle_block(NULL); 1890 JNIHandleBlock::release_block(block); 1891 } 1892 1893 // These have to be removed while this is still a valid thread. 1894 remove_stack_guard_pages(); 1895 1896 if (UseTLAB) { 1897 tlab().make_parsable(true); // retire TLAB 1898 } 1899 1900 if (JvmtiEnv::environments_might_exist()) { 1901 JvmtiExport::cleanup_thread(this); 1902 } 1903 1904 // We must flush any deferred card marks before removing a thread from 1905 // the list of active threads. 1906 Universe::heap()->flush_deferred_store_barrier(this); 1907 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1908 1909 #if INCLUDE_ALL_GCS 1910 // We must flush the G1-related buffers before removing a thread 1911 // from the list of active threads. We must do this after any deferred 1912 // card marks have been flushed (above) so that any entries that are 1913 // added to the thread's dirty card queue as a result are not lost. 1914 if (UseG1GC) { 1915 flush_barrier_queues(); 1916 } 1917 #endif // INCLUDE_ALL_GCS 1918 1919 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1920 Threads::remove(this); 1921 } 1922 1923 #if INCLUDE_ALL_GCS 1924 // Flush G1-related queues. 1925 void JavaThread::flush_barrier_queues() { 1926 satb_mark_queue().flush(); 1927 dirty_card_queue().flush(); 1928 } 1929 1930 void JavaThread::initialize_queues() { 1931 assert(!SafepointSynchronize::is_at_safepoint(), 1932 "we should not be at a safepoint"); 1933 1934 ObjPtrQueue& satb_queue = satb_mark_queue(); 1935 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1936 // The SATB queue should have been constructed with its active 1937 // field set to false. 1938 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1939 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1940 // If we are creating the thread during a marking cycle, we should 1941 // set the active field of the SATB queue to true. 1942 if (satb_queue_set.is_active()) { 1943 satb_queue.set_active(true); 1944 } 1945 1946 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1947 // The dirty card queue should have been constructed with its 1948 // active field set to true. 1949 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1950 } 1951 #endif // INCLUDE_ALL_GCS 1952 1953 void JavaThread::cleanup_failed_attach_current_thread() { 1954 if (get_thread_profiler() != NULL) { 1955 get_thread_profiler()->disengage(); 1956 ResourceMark rm; 1957 get_thread_profiler()->print(get_thread_name()); 1958 } 1959 1960 if (active_handles() != NULL) { 1961 JNIHandleBlock* block = active_handles(); 1962 set_active_handles(NULL); 1963 JNIHandleBlock::release_block(block); 1964 } 1965 1966 if (free_handle_block() != NULL) { 1967 JNIHandleBlock* block = free_handle_block(); 1968 set_free_handle_block(NULL); 1969 JNIHandleBlock::release_block(block); 1970 } 1971 1972 // These have to be removed while this is still a valid thread. 1973 remove_stack_guard_pages(); 1974 1975 if (UseTLAB) { 1976 tlab().make_parsable(true); // retire TLAB, if any 1977 } 1978 1979 #if INCLUDE_ALL_GCS 1980 if (UseG1GC) { 1981 flush_barrier_queues(); 1982 } 1983 #endif // INCLUDE_ALL_GCS 1984 1985 Threads::remove(this); 1986 delete this; 1987 } 1988 1989 1990 1991 1992 JavaThread* JavaThread::active() { 1993 Thread* thread = ThreadLocalStorage::thread(); 1994 assert(thread != NULL, "just checking"); 1995 if (thread->is_Java_thread()) { 1996 return (JavaThread*) thread; 1997 } else { 1998 assert(thread->is_VM_thread(), "this must be a vm thread"); 1999 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2000 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2001 assert(ret->is_Java_thread(), "must be a Java thread"); 2002 return ret; 2003 } 2004 } 2005 2006 bool JavaThread::is_lock_owned(address adr) const { 2007 if (Thread::is_lock_owned(adr)) return true; 2008 2009 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2010 if (chunk->contains(adr)) return true; 2011 } 2012 2013 return false; 2014 } 2015 2016 2017 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2018 chunk->set_next(monitor_chunks()); 2019 set_monitor_chunks(chunk); 2020 } 2021 2022 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2023 guarantee(monitor_chunks() != NULL, "must be non empty"); 2024 if (monitor_chunks() == chunk) { 2025 set_monitor_chunks(chunk->next()); 2026 } else { 2027 MonitorChunk* prev = monitor_chunks(); 2028 while (prev->next() != chunk) prev = prev->next(); 2029 prev->set_next(chunk->next()); 2030 } 2031 } 2032 2033 // JVM support. 2034 2035 // Note: this function shouldn't block if it's called in 2036 // _thread_in_native_trans state (such as from 2037 // check_special_condition_for_native_trans()). 2038 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2039 2040 if (has_last_Java_frame() && has_async_condition()) { 2041 // If we are at a polling page safepoint (not a poll return) 2042 // then we must defer async exception because live registers 2043 // will be clobbered by the exception path. Poll return is 2044 // ok because the call we a returning from already collides 2045 // with exception handling registers and so there is no issue. 2046 // (The exception handling path kills call result registers but 2047 // this is ok since the exception kills the result anyway). 2048 2049 if (is_at_poll_safepoint()) { 2050 // if the code we are returning to has deoptimized we must defer 2051 // the exception otherwise live registers get clobbered on the 2052 // exception path before deoptimization is able to retrieve them. 2053 // 2054 RegisterMap map(this, false); 2055 frame caller_fr = last_frame().sender(&map); 2056 assert(caller_fr.is_compiled_frame(), "what?"); 2057 if (caller_fr.is_deoptimized_frame()) { 2058 if (TraceExceptions) { 2059 ResourceMark rm; 2060 tty->print_cr("deferred async exception at compiled safepoint"); 2061 } 2062 return; 2063 } 2064 } 2065 } 2066 2067 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2068 if (condition == _no_async_condition) { 2069 // Conditions have changed since has_special_runtime_exit_condition() 2070 // was called: 2071 // - if we were here only because of an external suspend request, 2072 // then that was taken care of above (or cancelled) so we are done 2073 // - if we were here because of another async request, then it has 2074 // been cleared between the has_special_runtime_exit_condition() 2075 // and now so again we are done 2076 return; 2077 } 2078 2079 // Check for pending async. exception 2080 if (_pending_async_exception != NULL) { 2081 // Only overwrite an already pending exception, if it is not a threadDeath. 2082 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2083 2084 // We cannot call Exceptions::_throw(...) here because we cannot block 2085 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2086 2087 if (TraceExceptions) { 2088 ResourceMark rm; 2089 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2090 if (has_last_Java_frame() ) { 2091 frame f = last_frame(); 2092 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2093 } 2094 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2095 } 2096 _pending_async_exception = NULL; 2097 clear_has_async_exception(); 2098 } 2099 } 2100 2101 if (check_unsafe_error && 2102 condition == _async_unsafe_access_error && !has_pending_exception()) { 2103 condition = _no_async_condition; // done 2104 switch (thread_state()) { 2105 case _thread_in_vm: 2106 { 2107 JavaThread* THREAD = this; 2108 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2109 } 2110 case _thread_in_native: 2111 { 2112 ThreadInVMfromNative tiv(this); 2113 JavaThread* THREAD = this; 2114 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2115 } 2116 case _thread_in_Java: 2117 { 2118 ThreadInVMfromJava tiv(this); 2119 JavaThread* THREAD = this; 2120 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2121 } 2122 default: 2123 ShouldNotReachHere(); 2124 } 2125 } 2126 2127 assert(condition == _no_async_condition || has_pending_exception() || 2128 (!check_unsafe_error && condition == _async_unsafe_access_error), 2129 "must have handled the async condition, if no exception"); 2130 } 2131 2132 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2133 // 2134 // Check for pending external suspend. Internal suspend requests do 2135 // not use handle_special_runtime_exit_condition(). 2136 // If JNIEnv proxies are allowed, don't self-suspend if the target 2137 // thread is not the current thread. In older versions of jdbx, jdbx 2138 // threads could call into the VM with another thread's JNIEnv so we 2139 // can be here operating on behalf of a suspended thread (4432884). 2140 bool do_self_suspend = is_external_suspend_with_lock(); 2141 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2142 // 2143 // Because thread is external suspended the safepoint code will count 2144 // thread as at a safepoint. This can be odd because we can be here 2145 // as _thread_in_Java which would normally transition to _thread_blocked 2146 // at a safepoint. We would like to mark the thread as _thread_blocked 2147 // before calling java_suspend_self like all other callers of it but 2148 // we must then observe proper safepoint protocol. (We can't leave 2149 // _thread_blocked with a safepoint in progress). However we can be 2150 // here as _thread_in_native_trans so we can't use a normal transition 2151 // constructor/destructor pair because they assert on that type of 2152 // transition. We could do something like: 2153 // 2154 // JavaThreadState state = thread_state(); 2155 // set_thread_state(_thread_in_vm); 2156 // { 2157 // ThreadBlockInVM tbivm(this); 2158 // java_suspend_self() 2159 // } 2160 // set_thread_state(_thread_in_vm_trans); 2161 // if (safepoint) block; 2162 // set_thread_state(state); 2163 // 2164 // but that is pretty messy. Instead we just go with the way the 2165 // code has worked before and note that this is the only path to 2166 // java_suspend_self that doesn't put the thread in _thread_blocked 2167 // mode. 2168 2169 frame_anchor()->make_walkable(this); 2170 java_suspend_self(); 2171 2172 // We might be here for reasons in addition to the self-suspend request 2173 // so check for other async requests. 2174 } 2175 2176 if (check_asyncs) { 2177 check_and_handle_async_exceptions(); 2178 } 2179 } 2180 2181 void JavaThread::send_thread_stop(oop java_throwable) { 2182 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2183 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2184 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2185 2186 // Do not throw asynchronous exceptions against the compiler thread 2187 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2188 if (is_Compiler_thread()) return; 2189 2190 { 2191 // Actually throw the Throwable against the target Thread - however 2192 // only if there is no thread death exception installed already. 2193 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2194 // If the topmost frame is a runtime stub, then we are calling into 2195 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2196 // must deoptimize the caller before continuing, as the compiled exception handler table 2197 // may not be valid 2198 if (has_last_Java_frame()) { 2199 frame f = last_frame(); 2200 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2201 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2202 RegisterMap reg_map(this, UseBiasedLocking); 2203 frame compiled_frame = f.sender(®_map); 2204 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2205 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2206 } 2207 } 2208 } 2209 2210 // Set async. pending exception in thread. 2211 set_pending_async_exception(java_throwable); 2212 2213 if (TraceExceptions) { 2214 ResourceMark rm; 2215 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2216 } 2217 // for AbortVMOnException flag 2218 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2219 } 2220 } 2221 2222 2223 // Interrupt thread so it will wake up from a potential wait() 2224 Thread::interrupt(this); 2225 } 2226 2227 // External suspension mechanism. 2228 // 2229 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2230 // to any VM_locks and it is at a transition 2231 // Self-suspension will happen on the transition out of the vm. 2232 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2233 // 2234 // Guarantees on return: 2235 // + Target thread will not execute any new bytecode (that's why we need to 2236 // force a safepoint) 2237 // + Target thread will not enter any new monitors 2238 // 2239 void JavaThread::java_suspend() { 2240 { MutexLocker mu(Threads_lock); 2241 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2242 return; 2243 } 2244 } 2245 2246 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2247 if (!is_external_suspend()) { 2248 // a racing resume has cancelled us; bail out now 2249 return; 2250 } 2251 2252 // suspend is done 2253 uint32_t debug_bits = 0; 2254 // Warning: is_ext_suspend_completed() may temporarily drop the 2255 // SR_lock to allow the thread to reach a stable thread state if 2256 // it is currently in a transient thread state. 2257 if (is_ext_suspend_completed(false /* !called_by_wait */, 2258 SuspendRetryDelay, &debug_bits) ) { 2259 return; 2260 } 2261 } 2262 2263 VM_ForceSafepoint vm_suspend; 2264 VMThread::execute(&vm_suspend); 2265 } 2266 2267 // Part II of external suspension. 2268 // A JavaThread self suspends when it detects a pending external suspend 2269 // request. This is usually on transitions. It is also done in places 2270 // where continuing to the next transition would surprise the caller, 2271 // e.g., monitor entry. 2272 // 2273 // Returns the number of times that the thread self-suspended. 2274 // 2275 // Note: DO NOT call java_suspend_self() when you just want to block current 2276 // thread. java_suspend_self() is the second stage of cooperative 2277 // suspension for external suspend requests and should only be used 2278 // to complete an external suspend request. 2279 // 2280 int JavaThread::java_suspend_self() { 2281 int ret = 0; 2282 2283 // we are in the process of exiting so don't suspend 2284 if (is_exiting()) { 2285 clear_external_suspend(); 2286 return ret; 2287 } 2288 2289 assert(_anchor.walkable() || 2290 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2291 "must have walkable stack"); 2292 2293 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2294 2295 assert(!this->is_ext_suspended(), 2296 "a thread trying to self-suspend should not already be suspended"); 2297 2298 if (this->is_suspend_equivalent()) { 2299 // If we are self-suspending as a result of the lifting of a 2300 // suspend equivalent condition, then the suspend_equivalent 2301 // flag is not cleared until we set the ext_suspended flag so 2302 // that wait_for_ext_suspend_completion() returns consistent 2303 // results. 2304 this->clear_suspend_equivalent(); 2305 } 2306 2307 // A racing resume may have cancelled us before we grabbed SR_lock 2308 // above. Or another external suspend request could be waiting for us 2309 // by the time we return from SR_lock()->wait(). The thread 2310 // that requested the suspension may already be trying to walk our 2311 // stack and if we return now, we can change the stack out from under 2312 // it. This would be a "bad thing (TM)" and cause the stack walker 2313 // to crash. We stay self-suspended until there are no more pending 2314 // external suspend requests. 2315 while (is_external_suspend()) { 2316 ret++; 2317 this->set_ext_suspended(); 2318 2319 // _ext_suspended flag is cleared by java_resume() 2320 while (is_ext_suspended()) { 2321 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2322 } 2323 } 2324 2325 return ret; 2326 } 2327 2328 #ifdef ASSERT 2329 // verify the JavaThread has not yet been published in the Threads::list, and 2330 // hence doesn't need protection from concurrent access at this stage 2331 void JavaThread::verify_not_published() { 2332 if (!Threads_lock->owned_by_self()) { 2333 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2334 assert( !Threads::includes(this), 2335 "java thread shouldn't have been published yet!"); 2336 } 2337 else { 2338 assert( !Threads::includes(this), 2339 "java thread shouldn't have been published yet!"); 2340 } 2341 } 2342 #endif 2343 2344 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2345 // progress or when _suspend_flags is non-zero. 2346 // Current thread needs to self-suspend if there is a suspend request and/or 2347 // block if a safepoint is in progress. 2348 // Async exception ISN'T checked. 2349 // Note only the ThreadInVMfromNative transition can call this function 2350 // directly and when thread state is _thread_in_native_trans 2351 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2352 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2353 2354 JavaThread *curJT = JavaThread::current(); 2355 bool do_self_suspend = thread->is_external_suspend(); 2356 2357 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2358 2359 // If JNIEnv proxies are allowed, don't self-suspend if the target 2360 // thread is not the current thread. In older versions of jdbx, jdbx 2361 // threads could call into the VM with another thread's JNIEnv so we 2362 // can be here operating on behalf of a suspended thread (4432884). 2363 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2364 JavaThreadState state = thread->thread_state(); 2365 2366 // We mark this thread_blocked state as a suspend-equivalent so 2367 // that a caller to is_ext_suspend_completed() won't be confused. 2368 // The suspend-equivalent state is cleared by java_suspend_self(). 2369 thread->set_suspend_equivalent(); 2370 2371 // If the safepoint code sees the _thread_in_native_trans state, it will 2372 // wait until the thread changes to other thread state. There is no 2373 // guarantee on how soon we can obtain the SR_lock and complete the 2374 // self-suspend request. It would be a bad idea to let safepoint wait for 2375 // too long. Temporarily change the state to _thread_blocked to 2376 // let the VM thread know that this thread is ready for GC. The problem 2377 // of changing thread state is that safepoint could happen just after 2378 // java_suspend_self() returns after being resumed, and VM thread will 2379 // see the _thread_blocked state. We must check for safepoint 2380 // after restoring the state and make sure we won't leave while a safepoint 2381 // is in progress. 2382 thread->set_thread_state(_thread_blocked); 2383 thread->java_suspend_self(); 2384 thread->set_thread_state(state); 2385 // Make sure new state is seen by VM thread 2386 if (os::is_MP()) { 2387 if (UseMembar) { 2388 // Force a fence between the write above and read below 2389 OrderAccess::fence(); 2390 } else { 2391 // Must use this rather than serialization page in particular on Windows 2392 InterfaceSupport::serialize_memory(thread); 2393 } 2394 } 2395 } 2396 2397 if (SafepointSynchronize::do_call_back()) { 2398 // If we are safepointing, then block the caller which may not be 2399 // the same as the target thread (see above). 2400 SafepointSynchronize::block(curJT); 2401 } 2402 2403 if (thread->is_deopt_suspend()) { 2404 thread->clear_deopt_suspend(); 2405 RegisterMap map(thread, false); 2406 frame f = thread->last_frame(); 2407 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2408 f = f.sender(&map); 2409 } 2410 if (f.id() == thread->must_deopt_id()) { 2411 thread->clear_must_deopt_id(); 2412 f.deoptimize(thread); 2413 } else { 2414 fatal("missed deoptimization!"); 2415 } 2416 } 2417 } 2418 2419 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2420 // progress or when _suspend_flags is non-zero. 2421 // Current thread needs to self-suspend if there is a suspend request and/or 2422 // block if a safepoint is in progress. 2423 // Also check for pending async exception (not including unsafe access error). 2424 // Note only the native==>VM/Java barriers can call this function and when 2425 // thread state is _thread_in_native_trans. 2426 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2427 check_safepoint_and_suspend_for_native_trans(thread); 2428 2429 if (thread->has_async_exception()) { 2430 // We are in _thread_in_native_trans state, don't handle unsafe 2431 // access error since that may block. 2432 thread->check_and_handle_async_exceptions(false); 2433 } 2434 } 2435 2436 // This is a variant of the normal 2437 // check_special_condition_for_native_trans with slightly different 2438 // semantics for use by critical native wrappers. It does all the 2439 // normal checks but also performs the transition back into 2440 // thread_in_Java state. This is required so that critical natives 2441 // can potentially block and perform a GC if they are the last thread 2442 // exiting the GC_locker. 2443 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2444 check_special_condition_for_native_trans(thread); 2445 2446 // Finish the transition 2447 thread->set_thread_state(_thread_in_Java); 2448 2449 if (thread->do_critical_native_unlock()) { 2450 ThreadInVMfromJavaNoAsyncException tiv(thread); 2451 GC_locker::unlock_critical(thread); 2452 thread->clear_critical_native_unlock(); 2453 } 2454 } 2455 2456 // We need to guarantee the Threads_lock here, since resumes are not 2457 // allowed during safepoint synchronization 2458 // Can only resume from an external suspension 2459 void JavaThread::java_resume() { 2460 assert_locked_or_safepoint(Threads_lock); 2461 2462 // Sanity check: thread is gone, has started exiting or the thread 2463 // was not externally suspended. 2464 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2465 return; 2466 } 2467 2468 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2469 2470 clear_external_suspend(); 2471 2472 if (is_ext_suspended()) { 2473 clear_ext_suspended(); 2474 SR_lock()->notify_all(); 2475 } 2476 } 2477 2478 void JavaThread::create_stack_guard_pages() { 2479 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2480 address low_addr = stack_base() - stack_size(); 2481 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2482 2483 int allocate = os::allocate_stack_guard_pages(); 2484 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2485 2486 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2487 warning("Attempt to allocate stack guard pages failed."); 2488 return; 2489 } 2490 2491 if (os::guard_memory((char *) low_addr, len)) { 2492 _stack_guard_state = stack_guard_enabled; 2493 } else { 2494 warning("Attempt to protect stack guard pages failed."); 2495 if (os::uncommit_memory((char *) low_addr, len)) { 2496 warning("Attempt to deallocate stack guard pages failed."); 2497 } 2498 } 2499 } 2500 2501 void JavaThread::remove_stack_guard_pages() { 2502 assert(Thread::current() == this, "from different thread"); 2503 if (_stack_guard_state == stack_guard_unused) return; 2504 address low_addr = stack_base() - stack_size(); 2505 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2506 2507 if (os::allocate_stack_guard_pages()) { 2508 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2509 _stack_guard_state = stack_guard_unused; 2510 } else { 2511 warning("Attempt to deallocate stack guard pages failed."); 2512 } 2513 } else { 2514 if (_stack_guard_state == stack_guard_unused) return; 2515 if (os::unguard_memory((char *) low_addr, len)) { 2516 _stack_guard_state = stack_guard_unused; 2517 } else { 2518 warning("Attempt to unprotect stack guard pages failed."); 2519 } 2520 } 2521 } 2522 2523 void JavaThread::enable_stack_yellow_zone() { 2524 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2525 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2526 2527 // The base notation is from the stacks point of view, growing downward. 2528 // We need to adjust it to work correctly with guard_memory() 2529 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2530 2531 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2532 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2533 2534 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2535 _stack_guard_state = stack_guard_enabled; 2536 } else { 2537 warning("Attempt to guard stack yellow zone failed."); 2538 } 2539 enable_register_stack_guard(); 2540 } 2541 2542 void JavaThread::disable_stack_yellow_zone() { 2543 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2544 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2545 2546 // Simply return if called for a thread that does not use guard pages. 2547 if (_stack_guard_state == stack_guard_unused) return; 2548 2549 // The base notation is from the stacks point of view, growing downward. 2550 // We need to adjust it to work correctly with guard_memory() 2551 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2552 2553 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2554 _stack_guard_state = stack_guard_yellow_disabled; 2555 } else { 2556 warning("Attempt to unguard stack yellow zone failed."); 2557 } 2558 disable_register_stack_guard(); 2559 } 2560 2561 void JavaThread::enable_stack_red_zone() { 2562 // The base notation is from the stacks point of view, growing downward. 2563 // We need to adjust it to work correctly with guard_memory() 2564 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2565 address base = stack_red_zone_base() - stack_red_zone_size(); 2566 2567 guarantee(base < stack_base(),"Error calculating stack red zone"); 2568 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2569 2570 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2571 warning("Attempt to guard stack red zone failed."); 2572 } 2573 } 2574 2575 void JavaThread::disable_stack_red_zone() { 2576 // The base notation is from the stacks point of view, growing downward. 2577 // We need to adjust it to work correctly with guard_memory() 2578 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2579 address base = stack_red_zone_base() - stack_red_zone_size(); 2580 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2581 warning("Attempt to unguard stack red zone failed."); 2582 } 2583 } 2584 2585 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2586 // ignore is there is no stack 2587 if (!has_last_Java_frame()) return; 2588 // traverse the stack frames. Starts from top frame. 2589 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2590 frame* fr = fst.current(); 2591 f(fr, fst.register_map()); 2592 } 2593 } 2594 2595 2596 #ifndef PRODUCT 2597 // Deoptimization 2598 // Function for testing deoptimization 2599 void JavaThread::deoptimize() { 2600 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2601 StackFrameStream fst(this, UseBiasedLocking); 2602 bool deopt = false; // Dump stack only if a deopt actually happens. 2603 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2604 // Iterate over all frames in the thread and deoptimize 2605 for(; !fst.is_done(); fst.next()) { 2606 if(fst.current()->can_be_deoptimized()) { 2607 2608 if (only_at) { 2609 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2610 // consists of comma or carriage return separated numbers so 2611 // search for the current bci in that string. 2612 address pc = fst.current()->pc(); 2613 nmethod* nm = (nmethod*) fst.current()->cb(); 2614 ScopeDesc* sd = nm->scope_desc_at( pc); 2615 char buffer[8]; 2616 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2617 size_t len = strlen(buffer); 2618 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2619 while (found != NULL) { 2620 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2621 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2622 // Check that the bci found is bracketed by terminators. 2623 break; 2624 } 2625 found = strstr(found + 1, buffer); 2626 } 2627 if (!found) { 2628 continue; 2629 } 2630 } 2631 2632 if (DebugDeoptimization && !deopt) { 2633 deopt = true; // One-time only print before deopt 2634 tty->print_cr("[BEFORE Deoptimization]"); 2635 trace_frames(); 2636 trace_stack(); 2637 } 2638 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2639 } 2640 } 2641 2642 if (DebugDeoptimization && deopt) { 2643 tty->print_cr("[AFTER Deoptimization]"); 2644 trace_frames(); 2645 } 2646 } 2647 2648 2649 // Make zombies 2650 void JavaThread::make_zombies() { 2651 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2652 if (fst.current()->can_be_deoptimized()) { 2653 // it is a Java nmethod 2654 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2655 nm->make_not_entrant(); 2656 } 2657 } 2658 } 2659 #endif // PRODUCT 2660 2661 2662 void JavaThread::deoptimized_wrt_marked_nmethods() { 2663 if (!has_last_Java_frame()) return; 2664 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2665 StackFrameStream fst(this, UseBiasedLocking); 2666 for(; !fst.is_done(); fst.next()) { 2667 if (fst.current()->should_be_deoptimized()) { 2668 if (LogCompilation && xtty != NULL) { 2669 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2670 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2671 this->name(), nm != NULL ? nm->compile_id() : -1); 2672 } 2673 2674 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2675 } 2676 } 2677 } 2678 2679 2680 // GC support 2681 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2682 2683 void JavaThread::gc_epilogue() { 2684 frames_do(frame_gc_epilogue); 2685 } 2686 2687 2688 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2689 2690 void JavaThread::gc_prologue() { 2691 frames_do(frame_gc_prologue); 2692 } 2693 2694 // If the caller is a NamedThread, then remember, in the current scope, 2695 // the given JavaThread in its _processed_thread field. 2696 class RememberProcessedThread: public StackObj { 2697 NamedThread* _cur_thr; 2698 public: 2699 RememberProcessedThread(JavaThread* jthr) { 2700 Thread* thread = Thread::current(); 2701 if (thread->is_Named_thread()) { 2702 _cur_thr = (NamedThread *)thread; 2703 _cur_thr->set_processed_thread(jthr); 2704 } else { 2705 _cur_thr = NULL; 2706 } 2707 } 2708 2709 ~RememberProcessedThread() { 2710 if (_cur_thr) { 2711 _cur_thr->set_processed_thread(NULL); 2712 } 2713 } 2714 }; 2715 2716 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 2717 // Verify that the deferred card marks have been flushed. 2718 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2719 2720 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2721 // since there may be more than one thread using each ThreadProfiler. 2722 2723 // Traverse the GCHandles 2724 Thread::oops_do(f, cld_f, cf); 2725 2726 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2727 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2728 2729 if (has_last_Java_frame()) { 2730 // Record JavaThread to GC thread 2731 RememberProcessedThread rpt(this); 2732 2733 // Traverse the privileged stack 2734 if (_privileged_stack_top != NULL) { 2735 _privileged_stack_top->oops_do(f); 2736 } 2737 2738 // traverse the registered growable array 2739 if (_array_for_gc != NULL) { 2740 for (int index = 0; index < _array_for_gc->length(); index++) { 2741 f->do_oop(_array_for_gc->adr_at(index)); 2742 } 2743 } 2744 2745 // Traverse the monitor chunks 2746 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2747 chunk->oops_do(f); 2748 } 2749 2750 // Traverse the execution stack 2751 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2752 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2753 } 2754 } 2755 2756 // callee_target is never live across a gc point so NULL it here should 2757 // it still contain a methdOop. 2758 2759 set_callee_target(NULL); 2760 2761 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2762 // If we have deferred set_locals there might be oops waiting to be 2763 // written 2764 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2765 if (list != NULL) { 2766 for (int i = 0; i < list->length(); i++) { 2767 list->at(i)->oops_do(f); 2768 } 2769 } 2770 2771 // Traverse instance variables at the end since the GC may be moving things 2772 // around using this function 2773 f->do_oop((oop*) &_threadObj); 2774 f->do_oop((oop*) &_vm_result); 2775 f->do_oop((oop*) &_exception_oop); 2776 f->do_oop((oop*) &_pending_async_exception); 2777 2778 if (jvmti_thread_state() != NULL) { 2779 jvmti_thread_state()->oops_do(f); 2780 } 2781 } 2782 2783 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2784 Thread::nmethods_do(cf); // (super method is a no-op) 2785 2786 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2787 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2788 2789 if (has_last_Java_frame()) { 2790 // Traverse the execution stack 2791 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2792 fst.current()->nmethods_do(cf); 2793 } 2794 } 2795 } 2796 2797 void JavaThread::metadata_do(void f(Metadata*)) { 2798 Thread::metadata_do(f); 2799 if (has_last_Java_frame()) { 2800 // Traverse the execution stack to call f() on the methods in the stack 2801 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2802 fst.current()->metadata_do(f); 2803 } 2804 } else if (is_Compiler_thread()) { 2805 // need to walk ciMetadata in current compile tasks to keep alive. 2806 CompilerThread* ct = (CompilerThread*)this; 2807 if (ct->env() != NULL) { 2808 ct->env()->metadata_do(f); 2809 } 2810 } 2811 } 2812 2813 // Printing 2814 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2815 switch (_thread_state) { 2816 case _thread_uninitialized: return "_thread_uninitialized"; 2817 case _thread_new: return "_thread_new"; 2818 case _thread_new_trans: return "_thread_new_trans"; 2819 case _thread_in_native: return "_thread_in_native"; 2820 case _thread_in_native_trans: return "_thread_in_native_trans"; 2821 case _thread_in_vm: return "_thread_in_vm"; 2822 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2823 case _thread_in_Java: return "_thread_in_Java"; 2824 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2825 case _thread_blocked: return "_thread_blocked"; 2826 case _thread_blocked_trans: return "_thread_blocked_trans"; 2827 default: return "unknown thread state"; 2828 } 2829 } 2830 2831 #ifndef PRODUCT 2832 void JavaThread::print_thread_state_on(outputStream *st) const { 2833 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2834 }; 2835 void JavaThread::print_thread_state() const { 2836 print_thread_state_on(tty); 2837 }; 2838 #endif // PRODUCT 2839 2840 // Called by Threads::print() for VM_PrintThreads operation 2841 void JavaThread::print_on(outputStream *st) const { 2842 st->print("\"%s\" ", get_thread_name()); 2843 oop thread_oop = threadObj(); 2844 if (thread_oop != NULL) { 2845 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2846 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2847 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2848 } 2849 Thread::print_on(st); 2850 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2851 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2852 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2853 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2854 } 2855 #ifndef PRODUCT 2856 print_thread_state_on(st); 2857 _safepoint_state->print_on(st); 2858 #endif // PRODUCT 2859 } 2860 2861 // Called by fatal error handler. The difference between this and 2862 // JavaThread::print() is that we can't grab lock or allocate memory. 2863 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2864 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2865 oop thread_obj = threadObj(); 2866 if (thread_obj != NULL) { 2867 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2868 } 2869 st->print(" ["); 2870 st->print("%s", _get_thread_state_name(_thread_state)); 2871 if (osthread()) { 2872 st->print(", id=%d", osthread()->thread_id()); 2873 } 2874 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2875 _stack_base - _stack_size, _stack_base); 2876 st->print("]"); 2877 return; 2878 } 2879 2880 // Verification 2881 2882 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2883 2884 void JavaThread::verify() { 2885 // Verify oops in the thread. 2886 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2887 2888 // Verify the stack frames. 2889 frames_do(frame_verify); 2890 } 2891 2892 // CR 6300358 (sub-CR 2137150) 2893 // Most callers of this method assume that it can't return NULL but a 2894 // thread may not have a name whilst it is in the process of attaching to 2895 // the VM - see CR 6412693, and there are places where a JavaThread can be 2896 // seen prior to having it's threadObj set (eg JNI attaching threads and 2897 // if vm exit occurs during initialization). These cases can all be accounted 2898 // for such that this method never returns NULL. 2899 const char* JavaThread::get_thread_name() const { 2900 #ifdef ASSERT 2901 // early safepoints can hit while current thread does not yet have TLS 2902 if (!SafepointSynchronize::is_at_safepoint()) { 2903 Thread *cur = Thread::current(); 2904 if (!(cur->is_Java_thread() && cur == this)) { 2905 // Current JavaThreads are allowed to get their own name without 2906 // the Threads_lock. 2907 assert_locked_or_safepoint(Threads_lock); 2908 } 2909 } 2910 #endif // ASSERT 2911 return get_thread_name_string(); 2912 } 2913 2914 // Returns a non-NULL representation of this thread's name, or a suitable 2915 // descriptive string if there is no set name 2916 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2917 const char* name_str; 2918 oop thread_obj = threadObj(); 2919 if (thread_obj != NULL) { 2920 typeArrayOop name = java_lang_Thread::name(thread_obj); 2921 if (name != NULL) { 2922 if (buf == NULL) { 2923 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2924 } 2925 else { 2926 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2927 } 2928 } 2929 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2930 name_str = "<no-name - thread is attaching>"; 2931 } 2932 else { 2933 name_str = Thread::name(); 2934 } 2935 } 2936 else { 2937 name_str = Thread::name(); 2938 } 2939 assert(name_str != NULL, "unexpected NULL thread name"); 2940 return name_str; 2941 } 2942 2943 2944 const char* JavaThread::get_threadgroup_name() const { 2945 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2946 oop thread_obj = threadObj(); 2947 if (thread_obj != NULL) { 2948 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2949 if (thread_group != NULL) { 2950 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2951 // ThreadGroup.name can be null 2952 if (name != NULL) { 2953 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2954 return str; 2955 } 2956 } 2957 } 2958 return NULL; 2959 } 2960 2961 const char* JavaThread::get_parent_name() const { 2962 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2963 oop thread_obj = threadObj(); 2964 if (thread_obj != NULL) { 2965 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2966 if (thread_group != NULL) { 2967 oop parent = java_lang_ThreadGroup::parent(thread_group); 2968 if (parent != NULL) { 2969 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2970 // ThreadGroup.name can be null 2971 if (name != NULL) { 2972 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2973 return str; 2974 } 2975 } 2976 } 2977 } 2978 return NULL; 2979 } 2980 2981 ThreadPriority JavaThread::java_priority() const { 2982 oop thr_oop = threadObj(); 2983 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2984 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2985 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2986 return priority; 2987 } 2988 2989 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2990 2991 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2992 // Link Java Thread object <-> C++ Thread 2993 2994 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2995 // and put it into a new Handle. The Handle "thread_oop" can then 2996 // be used to pass the C++ thread object to other methods. 2997 2998 // Set the Java level thread object (jthread) field of the 2999 // new thread (a JavaThread *) to C++ thread object using the 3000 // "thread_oop" handle. 3001 3002 // Set the thread field (a JavaThread *) of the 3003 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3004 3005 Handle thread_oop(Thread::current(), 3006 JNIHandles::resolve_non_null(jni_thread)); 3007 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3008 "must be initialized"); 3009 set_threadObj(thread_oop()); 3010 java_lang_Thread::set_thread(thread_oop(), this); 3011 3012 if (prio == NoPriority) { 3013 prio = java_lang_Thread::priority(thread_oop()); 3014 assert(prio != NoPriority, "A valid priority should be present"); 3015 } 3016 3017 // Push the Java priority down to the native thread; needs Threads_lock 3018 Thread::set_priority(this, prio); 3019 3020 // Add the new thread to the Threads list and set it in motion. 3021 // We must have threads lock in order to call Threads::add. 3022 // It is crucial that we do not block before the thread is 3023 // added to the Threads list for if a GC happens, then the java_thread oop 3024 // will not be visited by GC. 3025 Threads::add(this); 3026 } 3027 3028 oop JavaThread::current_park_blocker() { 3029 // Support for JSR-166 locks 3030 oop thread_oop = threadObj(); 3031 if (thread_oop != NULL && 3032 JDK_Version::current().supports_thread_park_blocker()) { 3033 return java_lang_Thread::park_blocker(thread_oop); 3034 } 3035 return NULL; 3036 } 3037 3038 3039 void JavaThread::print_stack_on(outputStream* st) { 3040 if (!has_last_Java_frame()) return; 3041 ResourceMark rm; 3042 HandleMark hm; 3043 3044 RegisterMap reg_map(this); 3045 vframe* start_vf = last_java_vframe(®_map); 3046 int count = 0; 3047 for (vframe* f = start_vf; f; f = f->sender() ) { 3048 if (f->is_java_frame()) { 3049 javaVFrame* jvf = javaVFrame::cast(f); 3050 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3051 3052 // Print out lock information 3053 if (JavaMonitorsInStackTrace) { 3054 jvf->print_lock_info_on(st, count); 3055 } 3056 } else { 3057 // Ignore non-Java frames 3058 } 3059 3060 // Bail-out case for too deep stacks 3061 count++; 3062 if (MaxJavaStackTraceDepth == count) return; 3063 } 3064 } 3065 3066 3067 // JVMTI PopFrame support 3068 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3069 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3070 if (in_bytes(size_in_bytes) != 0) { 3071 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3072 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3073 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3074 } 3075 } 3076 3077 void* JavaThread::popframe_preserved_args() { 3078 return _popframe_preserved_args; 3079 } 3080 3081 ByteSize JavaThread::popframe_preserved_args_size() { 3082 return in_ByteSize(_popframe_preserved_args_size); 3083 } 3084 3085 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3086 int sz = in_bytes(popframe_preserved_args_size()); 3087 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3088 return in_WordSize(sz / wordSize); 3089 } 3090 3091 void JavaThread::popframe_free_preserved_args() { 3092 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3093 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3094 _popframe_preserved_args = NULL; 3095 _popframe_preserved_args_size = 0; 3096 } 3097 3098 #ifndef PRODUCT 3099 3100 void JavaThread::trace_frames() { 3101 tty->print_cr("[Describe stack]"); 3102 int frame_no = 1; 3103 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3104 tty->print(" %d. ", frame_no++); 3105 fst.current()->print_value_on(tty,this); 3106 tty->cr(); 3107 } 3108 } 3109 3110 class PrintAndVerifyOopClosure: public OopClosure { 3111 protected: 3112 template <class T> inline void do_oop_work(T* p) { 3113 oop obj = oopDesc::load_decode_heap_oop(p); 3114 if (obj == NULL) return; 3115 tty->print(INTPTR_FORMAT ": ", p); 3116 if (obj->is_oop_or_null()) { 3117 if (obj->is_objArray()) { 3118 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3119 } else { 3120 obj->print(); 3121 } 3122 } else { 3123 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3124 } 3125 tty->cr(); 3126 } 3127 public: 3128 virtual void do_oop(oop* p) { do_oop_work(p); } 3129 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3130 }; 3131 3132 3133 static void oops_print(frame* f, const RegisterMap *map) { 3134 PrintAndVerifyOopClosure print; 3135 f->print_value(); 3136 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3137 } 3138 3139 // Print our all the locations that contain oops and whether they are 3140 // valid or not. This useful when trying to find the oldest frame 3141 // where an oop has gone bad since the frame walk is from youngest to 3142 // oldest. 3143 void JavaThread::trace_oops() { 3144 tty->print_cr("[Trace oops]"); 3145 frames_do(oops_print); 3146 } 3147 3148 3149 #ifdef ASSERT 3150 // Print or validate the layout of stack frames 3151 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3152 ResourceMark rm; 3153 PRESERVE_EXCEPTION_MARK; 3154 FrameValues values; 3155 int frame_no = 0; 3156 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3157 fst.current()->describe(values, ++frame_no); 3158 if (depth == frame_no) break; 3159 } 3160 if (validate_only) { 3161 values.validate(); 3162 } else { 3163 tty->print_cr("[Describe stack layout]"); 3164 values.print(this); 3165 } 3166 } 3167 #endif 3168 3169 void JavaThread::trace_stack_from(vframe* start_vf) { 3170 ResourceMark rm; 3171 int vframe_no = 1; 3172 for (vframe* f = start_vf; f; f = f->sender() ) { 3173 if (f->is_java_frame()) { 3174 javaVFrame::cast(f)->print_activation(vframe_no++); 3175 } else { 3176 f->print(); 3177 } 3178 if (vframe_no > StackPrintLimit) { 3179 tty->print_cr("...<more frames>..."); 3180 return; 3181 } 3182 } 3183 } 3184 3185 3186 void JavaThread::trace_stack() { 3187 if (!has_last_Java_frame()) return; 3188 ResourceMark rm; 3189 HandleMark hm; 3190 RegisterMap reg_map(this); 3191 trace_stack_from(last_java_vframe(®_map)); 3192 } 3193 3194 3195 #endif // PRODUCT 3196 3197 3198 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3199 assert(reg_map != NULL, "a map must be given"); 3200 frame f = last_frame(); 3201 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3202 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3203 } 3204 return NULL; 3205 } 3206 3207 3208 Klass* JavaThread::security_get_caller_class(int depth) { 3209 vframeStream vfst(this); 3210 vfst.security_get_caller_frame(depth); 3211 if (!vfst.at_end()) { 3212 return vfst.method()->method_holder(); 3213 } 3214 return NULL; 3215 } 3216 3217 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3218 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3219 CompileBroker::compiler_thread_loop(); 3220 } 3221 3222 // Create a CompilerThread 3223 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3224 : JavaThread(&compiler_thread_entry) { 3225 _env = NULL; 3226 _log = NULL; 3227 _task = NULL; 3228 _queue = queue; 3229 _counters = counters; 3230 _buffer_blob = NULL; 3231 _scanned_nmethod = NULL; 3232 3233 #ifndef PRODUCT 3234 _ideal_graph_printer = NULL; 3235 #endif 3236 } 3237 3238 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 3239 JavaThread::oops_do(f, cld_f, cf); 3240 if (_scanned_nmethod != NULL && cf != NULL) { 3241 // Safepoints can occur when the sweeper is scanning an nmethod so 3242 // process it here to make sure it isn't unloaded in the middle of 3243 // a scan. 3244 cf->do_code_blob(_scanned_nmethod); 3245 } 3246 } 3247 3248 // ======= Threads ======== 3249 3250 // The Threads class links together all active threads, and provides 3251 // operations over all threads. It is protected by its own Mutex 3252 // lock, which is also used in other contexts to protect thread 3253 // operations from having the thread being operated on from exiting 3254 // and going away unexpectedly (e.g., safepoint synchronization) 3255 3256 JavaThread* Threads::_thread_list = NULL; 3257 int Threads::_number_of_threads = 0; 3258 int Threads::_number_of_non_daemon_threads = 0; 3259 int Threads::_return_code = 0; 3260 size_t JavaThread::_stack_size_at_create = 0; 3261 #ifdef ASSERT 3262 bool Threads::_vm_complete = false; 3263 #endif 3264 3265 // All JavaThreads 3266 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3267 3268 void os_stream(); 3269 3270 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3271 void Threads::threads_do(ThreadClosure* tc) { 3272 assert_locked_or_safepoint(Threads_lock); 3273 // ALL_JAVA_THREADS iterates through all JavaThreads 3274 ALL_JAVA_THREADS(p) { 3275 tc->do_thread(p); 3276 } 3277 // Someday we could have a table or list of all non-JavaThreads. 3278 // For now, just manually iterate through them. 3279 tc->do_thread(VMThread::vm_thread()); 3280 Universe::heap()->gc_threads_do(tc); 3281 WatcherThread *wt = WatcherThread::watcher_thread(); 3282 // Strictly speaking, the following NULL check isn't sufficient to make sure 3283 // the data for WatcherThread is still valid upon being examined. However, 3284 // considering that WatchThread terminates when the VM is on the way to 3285 // exit at safepoint, the chance of the above is extremely small. The right 3286 // way to prevent termination of WatcherThread would be to acquire 3287 // Terminator_lock, but we can't do that without violating the lock rank 3288 // checking in some cases. 3289 if (wt != NULL) 3290 tc->do_thread(wt); 3291 3292 // If CompilerThreads ever become non-JavaThreads, add them here 3293 } 3294 3295 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3296 3297 extern void JDK_Version_init(); 3298 3299 // Check version 3300 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3301 3302 // Initialize the output stream module 3303 ostream_init(); 3304 3305 // Process java launcher properties. 3306 Arguments::process_sun_java_launcher_properties(args); 3307 3308 // Initialize the os module before using TLS 3309 os::init(); 3310 3311 // Initialize system properties. 3312 Arguments::init_system_properties(); 3313 3314 // So that JDK version can be used as a discrimintor when parsing arguments 3315 JDK_Version_init(); 3316 3317 // Update/Initialize System properties after JDK version number is known 3318 Arguments::init_version_specific_system_properties(); 3319 3320 // Parse arguments 3321 jint parse_result = Arguments::parse(args); 3322 if (parse_result != JNI_OK) return parse_result; 3323 3324 if (PauseAtStartup) { 3325 os::pause(); 3326 } 3327 3328 #ifndef USDT2 3329 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3330 #else /* USDT2 */ 3331 HOTSPOT_VM_INIT_BEGIN(); 3332 #endif /* USDT2 */ 3333 3334 // Record VM creation timing statistics 3335 TraceVmCreationTime create_vm_timer; 3336 create_vm_timer.start(); 3337 3338 // Timing (must come after argument parsing) 3339 TraceTime timer("Create VM", TraceStartupTime); 3340 3341 // Initialize the os module after parsing the args 3342 jint os_init_2_result = os::init_2(); 3343 if (os_init_2_result != JNI_OK) return os_init_2_result; 3344 3345 jint adjust_after_os_result = Arguments::adjust_after_os(); 3346 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3347 3348 // intialize TLS 3349 ThreadLocalStorage::init(); 3350 3351 // Bootstrap native memory tracking, so it can start recording memory 3352 // activities before worker thread is started. This is the first phase 3353 // of bootstrapping, VM is currently running in single-thread mode. 3354 MemTracker::bootstrap_single_thread(); 3355 3356 // Initialize output stream logging 3357 ostream_init_log(); 3358 3359 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3360 // Must be before create_vm_init_agents() 3361 if (Arguments::init_libraries_at_startup()) { 3362 convert_vm_init_libraries_to_agents(); 3363 } 3364 3365 // Launch -agentlib/-agentpath and converted -Xrun agents 3366 if (Arguments::init_agents_at_startup()) { 3367 create_vm_init_agents(); 3368 } 3369 3370 // Initialize Threads state 3371 _thread_list = NULL; 3372 _number_of_threads = 0; 3373 _number_of_non_daemon_threads = 0; 3374 3375 // Initialize global data structures and create system classes in heap 3376 vm_init_globals(); 3377 3378 // Attach the main thread to this os thread 3379 JavaThread* main_thread = new JavaThread(); 3380 main_thread->set_thread_state(_thread_in_vm); 3381 // must do this before set_active_handles and initialize_thread_local_storage 3382 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3383 // change the stack size recorded here to one based on the java thread 3384 // stacksize. This adjusted size is what is used to figure the placement 3385 // of the guard pages. 3386 main_thread->record_stack_base_and_size(); 3387 main_thread->initialize_thread_local_storage(); 3388 3389 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3390 3391 if (!main_thread->set_as_starting_thread()) { 3392 vm_shutdown_during_initialization( 3393 "Failed necessary internal allocation. Out of swap space"); 3394 delete main_thread; 3395 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3396 return JNI_ENOMEM; 3397 } 3398 3399 // Enable guard page *after* os::create_main_thread(), otherwise it would 3400 // crash Linux VM, see notes in os_linux.cpp. 3401 main_thread->create_stack_guard_pages(); 3402 3403 // Initialize Java-Level synchronization subsystem 3404 ObjectMonitor::Initialize() ; 3405 3406 // Second phase of bootstrapping, VM is about entering multi-thread mode 3407 MemTracker::bootstrap_multi_thread(); 3408 3409 // Initialize global modules 3410 jint status = init_globals(); 3411 if (status != JNI_OK) { 3412 delete main_thread; 3413 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3414 return status; 3415 } 3416 3417 // Should be done after the heap is fully created 3418 main_thread->cache_global_variables(); 3419 3420 HandleMark hm; 3421 3422 { MutexLocker mu(Threads_lock); 3423 Threads::add(main_thread); 3424 } 3425 3426 // Any JVMTI raw monitors entered in onload will transition into 3427 // real raw monitor. VM is setup enough here for raw monitor enter. 3428 JvmtiExport::transition_pending_onload_raw_monitors(); 3429 3430 // Fully start NMT 3431 MemTracker::start(); 3432 3433 // Create the VMThread 3434 { TraceTime timer("Start VMThread", TraceStartupTime); 3435 VMThread::create(); 3436 Thread* vmthread = VMThread::vm_thread(); 3437 3438 if (!os::create_thread(vmthread, os::vm_thread)) 3439 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3440 3441 // Wait for the VM thread to become ready, and VMThread::run to initialize 3442 // Monitors can have spurious returns, must always check another state flag 3443 { 3444 MutexLocker ml(Notify_lock); 3445 os::start_thread(vmthread); 3446 while (vmthread->active_handles() == NULL) { 3447 Notify_lock->wait(); 3448 } 3449 } 3450 } 3451 3452 assert (Universe::is_fully_initialized(), "not initialized"); 3453 if (VerifyDuringStartup) { 3454 // Make sure we're starting with a clean slate. 3455 VM_Verify verify_op; 3456 VMThread::execute(&verify_op); 3457 } 3458 3459 EXCEPTION_MARK; 3460 3461 // At this point, the Universe is initialized, but we have not executed 3462 // any byte code. Now is a good time (the only time) to dump out the 3463 // internal state of the JVM for sharing. 3464 if (DumpSharedSpaces) { 3465 MetaspaceShared::preload_and_dump(CHECK_0); 3466 ShouldNotReachHere(); 3467 } 3468 3469 // Always call even when there are not JVMTI environments yet, since environments 3470 // may be attached late and JVMTI must track phases of VM execution 3471 JvmtiExport::enter_start_phase(); 3472 3473 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3474 JvmtiExport::post_vm_start(); 3475 3476 { 3477 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3478 3479 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3480 create_vm_init_libraries(); 3481 } 3482 3483 initialize_class(vmSymbols::java_lang_String(), CHECK_0); 3484 3485 if (AggressiveOpts) { 3486 { 3487 // Forcibly initialize java/util/HashMap and mutate the private 3488 // static final "frontCacheEnabled" field before we start creating instances 3489 #ifdef ASSERT 3490 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3491 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 3492 #endif 3493 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3494 KlassHandle k = KlassHandle(THREAD, k_o); 3495 guarantee(k.not_null(), "Must find java/util/HashMap"); 3496 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3497 ik->initialize(CHECK_0); 3498 fieldDescriptor fd; 3499 // Possible we might not find this field; if so, don't break 3500 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3501 k()->java_mirror()->bool_field_put(fd.offset(), true); 3502 } 3503 } 3504 3505 if (UseStringCache) { 3506 // Forcibly initialize java/lang/StringValue and mutate the private 3507 // static final "stringCacheEnabled" field before we start creating instances 3508 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0); 3509 // Possible that StringValue isn't present: if so, silently don't break 3510 if (k_o != NULL) { 3511 KlassHandle k = KlassHandle(THREAD, k_o); 3512 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3513 ik->initialize(CHECK_0); 3514 fieldDescriptor fd; 3515 // Possible we might not find this field: if so, silently don't break 3516 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3517 k()->java_mirror()->bool_field_put(fd.offset(), true); 3518 } 3519 } 3520 } 3521 } 3522 3523 // Initialize java_lang.System (needed before creating the thread) 3524 initialize_class(vmSymbols::java_lang_System(), CHECK_0); 3525 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0); 3526 Handle thread_group = create_initial_thread_group(CHECK_0); 3527 Universe::set_main_thread_group(thread_group()); 3528 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0); 3529 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 3530 main_thread->set_threadObj(thread_object); 3531 // Set thread status to running since main thread has 3532 // been started and running. 3533 java_lang_Thread::set_thread_status(thread_object, 3534 java_lang_Thread::RUNNABLE); 3535 3536 // The VM creates & returns objects of this class. Make sure it's initialized. 3537 initialize_class(vmSymbols::java_lang_Class(), CHECK_0); 3538 3539 // The VM preresolves methods to these classes. Make sure that they get initialized 3540 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0); 3541 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0); 3542 call_initializeSystemClass(CHECK_0); 3543 3544 // get the Java runtime name after java.lang.System is initialized 3545 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3546 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3547 3548 // an instance of OutOfMemory exception has been allocated earlier 3549 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0); 3550 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0); 3551 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0); 3552 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0); 3553 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0); 3554 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0); 3555 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0); 3556 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0); 3557 } 3558 3559 // See : bugid 4211085. 3560 // Background : the static initializer of java.lang.Compiler tries to read 3561 // property"java.compiler" and read & write property "java.vm.info". 3562 // When a security manager is installed through the command line 3563 // option "-Djava.security.manager", the above properties are not 3564 // readable and the static initializer for java.lang.Compiler fails 3565 // resulting in a NoClassDefFoundError. This can happen in any 3566 // user code which calls methods in java.lang.Compiler. 3567 // Hack : the hack is to pre-load and initialize this class, so that only 3568 // system domains are on the stack when the properties are read. 3569 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3570 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3571 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3572 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3573 // Once that is done, we should remove this hack. 3574 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0); 3575 3576 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3577 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3578 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3579 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3580 // This should also be taken out as soon as 4211383 gets fixed. 3581 reset_vm_info_property(CHECK_0); 3582 3583 quicken_jni_functions(); 3584 3585 // Must be run after init_ft which initializes ft_enabled 3586 if (TRACE_INITIALIZE() != JNI_OK) { 3587 vm_exit_during_initialization("Failed to initialize tracing backend"); 3588 } 3589 3590 // Set flag that basic initialization has completed. Used by exceptions and various 3591 // debug stuff, that does not work until all basic classes have been initialized. 3592 set_init_completed(); 3593 3594 #ifndef USDT2 3595 HS_DTRACE_PROBE(hotspot, vm__init__end); 3596 #else /* USDT2 */ 3597 HOTSPOT_VM_INIT_END(); 3598 #endif /* USDT2 */ 3599 3600 // record VM initialization completion time 3601 #if INCLUDE_MANAGEMENT 3602 Management::record_vm_init_completed(); 3603 #endif // INCLUDE_MANAGEMENT 3604 3605 // Compute system loader. Note that this has to occur after set_init_completed, since 3606 // valid exceptions may be thrown in the process. 3607 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3608 // set_init_completed has just been called, causing exceptions not to be shortcut 3609 // anymore. We call vm_exit_during_initialization directly instead. 3610 SystemDictionary::compute_java_system_loader(THREAD); 3611 if (HAS_PENDING_EXCEPTION) { 3612 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3613 } 3614 3615 #if INCLUDE_ALL_GCS 3616 // Support for ConcurrentMarkSweep. This should be cleaned up 3617 // and better encapsulated. The ugly nested if test would go away 3618 // once things are properly refactored. XXX YSR 3619 if (UseConcMarkSweepGC || UseG1GC) { 3620 if (UseConcMarkSweepGC) { 3621 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3622 } else { 3623 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3624 } 3625 if (HAS_PENDING_EXCEPTION) { 3626 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3627 } 3628 } 3629 #endif // INCLUDE_ALL_GCS 3630 3631 // Always call even when there are not JVMTI environments yet, since environments 3632 // may be attached late and JVMTI must track phases of VM execution 3633 JvmtiExport::enter_live_phase(); 3634 3635 // Signal Dispatcher needs to be started before VMInit event is posted 3636 os::signal_init(); 3637 3638 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3639 if (!DisableAttachMechanism) { 3640 if (StartAttachListener || AttachListener::init_at_startup()) { 3641 AttachListener::init(); 3642 } 3643 } 3644 3645 // Launch -Xrun agents 3646 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3647 // back-end can launch with -Xdebug -Xrunjdwp. 3648 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3649 create_vm_init_libraries(); 3650 } 3651 3652 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3653 JvmtiExport::post_vm_initialized(); 3654 3655 if (TRACE_START() != JNI_OK) { 3656 vm_exit_during_initialization("Failed to start tracing backend."); 3657 } 3658 3659 if (CleanChunkPoolAsync) { 3660 Chunk::start_chunk_pool_cleaner_task(); 3661 } 3662 3663 // initialize compiler(s) 3664 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3665 CompileBroker::compilation_init(); 3666 #endif 3667 3668 #if INCLUDE_MANAGEMENT 3669 Management::initialize(THREAD); 3670 #endif // INCLUDE_MANAGEMENT 3671 3672 if (HAS_PENDING_EXCEPTION) { 3673 // management agent fails to start possibly due to 3674 // configuration problem and is responsible for printing 3675 // stack trace if appropriate. Simply exit VM. 3676 vm_exit(1); 3677 } 3678 3679 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3680 if (Arguments::has_alloc_profile()) AllocationProfiler::engage(); 3681 if (MemProfiling) MemProfiler::engage(); 3682 StatSampler::engage(); 3683 if (CheckJNICalls) JniPeriodicChecker::engage(); 3684 3685 BiasedLocking::init(); 3686 3687 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3688 call_postVMInitHook(THREAD); 3689 // The Java side of PostVMInitHook.run must deal with all 3690 // exceptions and provide means of diagnosis. 3691 if (HAS_PENDING_EXCEPTION) { 3692 CLEAR_PENDING_EXCEPTION; 3693 } 3694 } 3695 3696 { 3697 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3698 // Make sure the watcher thread can be started by WatcherThread::start() 3699 // or by dynamic enrollment. 3700 WatcherThread::make_startable(); 3701 // Start up the WatcherThread if there are any periodic tasks 3702 // NOTE: All PeriodicTasks should be registered by now. If they 3703 // aren't, late joiners might appear to start slowly (we might 3704 // take a while to process their first tick). 3705 if (PeriodicTask::num_tasks() > 0) { 3706 WatcherThread::start(); 3707 } 3708 } 3709 3710 // Give os specific code one last chance to start 3711 os::init_3(); 3712 3713 create_vm_timer.end(); 3714 #ifdef ASSERT 3715 _vm_complete = true; 3716 #endif 3717 return JNI_OK; 3718 } 3719 3720 // type for the Agent_OnLoad and JVM_OnLoad entry points 3721 extern "C" { 3722 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3723 } 3724 // Find a command line agent library and return its entry point for 3725 // -agentlib: -agentpath: -Xrun 3726 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3727 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3728 OnLoadEntry_t on_load_entry = NULL; 3729 void *library = agent->os_lib(); // check if we have looked it up before 3730 3731 if (library == NULL) { 3732 char buffer[JVM_MAXPATHLEN]; 3733 char ebuf[1024]; 3734 const char *name = agent->name(); 3735 const char *msg = "Could not find agent library "; 3736 3737 if (agent->is_absolute_path()) { 3738 library = os::dll_load(name, ebuf, sizeof ebuf); 3739 if (library == NULL) { 3740 const char *sub_msg = " in absolute path, with error: "; 3741 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3742 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3743 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3744 // If we can't find the agent, exit. 3745 vm_exit_during_initialization(buf, NULL); 3746 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3747 } 3748 } else { 3749 // Try to load the agent from the standard dll directory 3750 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3751 name)) { 3752 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3753 } 3754 if (library == NULL) { // Try the local directory 3755 char ns[1] = {0}; 3756 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3757 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3758 } 3759 if (library == NULL) { 3760 const char *sub_msg = " on the library path, with error: "; 3761 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3762 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3763 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3764 // If we can't find the agent, exit. 3765 vm_exit_during_initialization(buf, NULL); 3766 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3767 } 3768 } 3769 } 3770 agent->set_os_lib(library); 3771 } 3772 3773 // Find the OnLoad function. 3774 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3775 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index])); 3776 if (on_load_entry != NULL) break; 3777 } 3778 return on_load_entry; 3779 } 3780 3781 // Find the JVM_OnLoad entry point 3782 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3783 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3784 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3785 } 3786 3787 // Find the Agent_OnLoad entry point 3788 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3789 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3790 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3791 } 3792 3793 // For backwards compatibility with -Xrun 3794 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3795 // treated like -agentpath: 3796 // Must be called before agent libraries are created 3797 void Threads::convert_vm_init_libraries_to_agents() { 3798 AgentLibrary* agent; 3799 AgentLibrary* next; 3800 3801 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3802 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3803 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3804 3805 // If there is an JVM_OnLoad function it will get called later, 3806 // otherwise see if there is an Agent_OnLoad 3807 if (on_load_entry == NULL) { 3808 on_load_entry = lookup_agent_on_load(agent); 3809 if (on_load_entry != NULL) { 3810 // switch it to the agent list -- so that Agent_OnLoad will be called, 3811 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3812 Arguments::convert_library_to_agent(agent); 3813 } else { 3814 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3815 } 3816 } 3817 } 3818 } 3819 3820 // Create agents for -agentlib: -agentpath: and converted -Xrun 3821 // Invokes Agent_OnLoad 3822 // Called very early -- before JavaThreads exist 3823 void Threads::create_vm_init_agents() { 3824 extern struct JavaVM_ main_vm; 3825 AgentLibrary* agent; 3826 3827 JvmtiExport::enter_onload_phase(); 3828 3829 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3830 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3831 3832 if (on_load_entry != NULL) { 3833 // Invoke the Agent_OnLoad function 3834 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3835 if (err != JNI_OK) { 3836 vm_exit_during_initialization("agent library failed to init", agent->name()); 3837 } 3838 } else { 3839 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3840 } 3841 } 3842 JvmtiExport::enter_primordial_phase(); 3843 } 3844 3845 extern "C" { 3846 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3847 } 3848 3849 void Threads::shutdown_vm_agents() { 3850 // Send any Agent_OnUnload notifications 3851 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3852 extern struct JavaVM_ main_vm; 3853 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3854 3855 // Find the Agent_OnUnload function. 3856 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3857 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3858 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3859 3860 // Invoke the Agent_OnUnload function 3861 if (unload_entry != NULL) { 3862 JavaThread* thread = JavaThread::current(); 3863 ThreadToNativeFromVM ttn(thread); 3864 HandleMark hm(thread); 3865 (*unload_entry)(&main_vm); 3866 break; 3867 } 3868 } 3869 } 3870 } 3871 3872 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3873 // Invokes JVM_OnLoad 3874 void Threads::create_vm_init_libraries() { 3875 extern struct JavaVM_ main_vm; 3876 AgentLibrary* agent; 3877 3878 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3879 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3880 3881 if (on_load_entry != NULL) { 3882 // Invoke the JVM_OnLoad function 3883 JavaThread* thread = JavaThread::current(); 3884 ThreadToNativeFromVM ttn(thread); 3885 HandleMark hm(thread); 3886 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3887 if (err != JNI_OK) { 3888 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3889 } 3890 } else { 3891 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3892 } 3893 } 3894 } 3895 3896 // Last thread running calls java.lang.Shutdown.shutdown() 3897 void JavaThread::invoke_shutdown_hooks() { 3898 HandleMark hm(this); 3899 3900 // We could get here with a pending exception, if so clear it now. 3901 if (this->has_pending_exception()) { 3902 this->clear_pending_exception(); 3903 } 3904 3905 EXCEPTION_MARK; 3906 Klass* k = 3907 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3908 THREAD); 3909 if (k != NULL) { 3910 // SystemDictionary::resolve_or_null will return null if there was 3911 // an exception. If we cannot load the Shutdown class, just don't 3912 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3913 // and finalizers (if runFinalizersOnExit is set) won't be run. 3914 // Note that if a shutdown hook was registered or runFinalizersOnExit 3915 // was called, the Shutdown class would have already been loaded 3916 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3917 instanceKlassHandle shutdown_klass (THREAD, k); 3918 JavaValue result(T_VOID); 3919 JavaCalls::call_static(&result, 3920 shutdown_klass, 3921 vmSymbols::shutdown_method_name(), 3922 vmSymbols::void_method_signature(), 3923 THREAD); 3924 } 3925 CLEAR_PENDING_EXCEPTION; 3926 } 3927 3928 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3929 // the program falls off the end of main(). Another VM exit path is through 3930 // vm_exit() when the program calls System.exit() to return a value or when 3931 // there is a serious error in VM. The two shutdown paths are not exactly 3932 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3933 // and VM_Exit op at VM level. 3934 // 3935 // Shutdown sequence: 3936 // + Shutdown native memory tracking if it is on 3937 // + Wait until we are the last non-daemon thread to execute 3938 // <-- every thing is still working at this moment --> 3939 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3940 // shutdown hooks, run finalizers if finalization-on-exit 3941 // + Call before_exit(), prepare for VM exit 3942 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3943 // currently the only user of this mechanism is File.deleteOnExit()) 3944 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3945 // post thread end and vm death events to JVMTI, 3946 // stop signal thread 3947 // + Call JavaThread::exit(), it will: 3948 // > release JNI handle blocks, remove stack guard pages 3949 // > remove this thread from Threads list 3950 // <-- no more Java code from this thread after this point --> 3951 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3952 // the compiler threads at safepoint 3953 // <-- do not use anything that could get blocked by Safepoint --> 3954 // + Disable tracing at JNI/JVM barriers 3955 // + Set _vm_exited flag for threads that are still running native code 3956 // + Delete this thread 3957 // + Call exit_globals() 3958 // > deletes tty 3959 // > deletes PerfMemory resources 3960 // + Return to caller 3961 3962 bool Threads::destroy_vm() { 3963 JavaThread* thread = JavaThread::current(); 3964 3965 #ifdef ASSERT 3966 _vm_complete = false; 3967 #endif 3968 // Wait until we are the last non-daemon thread to execute 3969 { MutexLocker nu(Threads_lock); 3970 while (Threads::number_of_non_daemon_threads() > 1 ) 3971 // This wait should make safepoint checks, wait without a timeout, 3972 // and wait as a suspend-equivalent condition. 3973 // 3974 // Note: If the FlatProfiler is running and this thread is waiting 3975 // for another non-daemon thread to finish, then the FlatProfiler 3976 // is waiting for the external suspend request on this thread to 3977 // complete. wait_for_ext_suspend_completion() will eventually 3978 // timeout, but that takes time. Making this wait a suspend- 3979 // equivalent condition solves that timeout problem. 3980 // 3981 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3982 Mutex::_as_suspend_equivalent_flag); 3983 } 3984 3985 // Hang forever on exit if we are reporting an error. 3986 if (ShowMessageBoxOnError && is_error_reported()) { 3987 os::infinite_sleep(); 3988 } 3989 os::wait_for_keypress_at_exit(); 3990 3991 if (JDK_Version::is_jdk12x_version()) { 3992 // We are the last thread running, so check if finalizers should be run. 3993 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3994 HandleMark rm(thread); 3995 Universe::run_finalizers_on_exit(); 3996 } else { 3997 // run Java level shutdown hooks 3998 thread->invoke_shutdown_hooks(); 3999 } 4000 4001 before_exit(thread); 4002 4003 thread->exit(true); 4004 4005 // Stop VM thread. 4006 { 4007 // 4945125 The vm thread comes to a safepoint during exit. 4008 // GC vm_operations can get caught at the safepoint, and the 4009 // heap is unparseable if they are caught. Grab the Heap_lock 4010 // to prevent this. The GC vm_operations will not be able to 4011 // queue until after the vm thread is dead. 4012 // After this point, we'll never emerge out of the safepoint before 4013 // the VM exits, so concurrent GC threads do not need to be explicitly 4014 // stopped; they remain inactive until the process exits. 4015 // Note: some concurrent G1 threads may be running during a safepoint, 4016 // but these will not be accessing the heap, just some G1-specific side 4017 // data structures that are not accessed by any other threads but them 4018 // after this point in a terminal safepoint. 4019 4020 MutexLocker ml(Heap_lock); 4021 4022 VMThread::wait_for_vm_thread_exit(); 4023 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4024 VMThread::destroy(); 4025 } 4026 4027 // clean up ideal graph printers 4028 #if defined(COMPILER2) && !defined(PRODUCT) 4029 IdealGraphPrinter::clean_up(); 4030 #endif 4031 4032 // Now, all Java threads are gone except daemon threads. Daemon threads 4033 // running Java code or in VM are stopped by the Safepoint. However, 4034 // daemon threads executing native code are still running. But they 4035 // will be stopped at native=>Java/VM barriers. Note that we can't 4036 // simply kill or suspend them, as it is inherently deadlock-prone. 4037 4038 #ifndef PRODUCT 4039 // disable function tracing at JNI/JVM barriers 4040 TraceJNICalls = false; 4041 TraceJVMCalls = false; 4042 TraceRuntimeCalls = false; 4043 #endif 4044 4045 VM_Exit::set_vm_exited(); 4046 4047 notify_vm_shutdown(); 4048 4049 delete thread; 4050 4051 // exit_globals() will delete tty 4052 exit_globals(); 4053 4054 return true; 4055 } 4056 4057 4058 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4059 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4060 return is_supported_jni_version(version); 4061 } 4062 4063 4064 jboolean Threads::is_supported_jni_version(jint version) { 4065 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4066 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4067 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4068 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4069 return JNI_FALSE; 4070 } 4071 4072 4073 void Threads::add(JavaThread* p, bool force_daemon) { 4074 // The threads lock must be owned at this point 4075 assert_locked_or_safepoint(Threads_lock); 4076 4077 // See the comment for this method in thread.hpp for its purpose and 4078 // why it is called here. 4079 p->initialize_queues(); 4080 p->set_next(_thread_list); 4081 _thread_list = p; 4082 _number_of_threads++; 4083 oop threadObj = p->threadObj(); 4084 bool daemon = true; 4085 // Bootstrapping problem: threadObj can be null for initial 4086 // JavaThread (or for threads attached via JNI) 4087 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4088 _number_of_non_daemon_threads++; 4089 daemon = false; 4090 } 4091 4092 p->set_safepoint_visible(true); 4093 4094 ThreadService::add_thread(p, daemon); 4095 4096 // Possible GC point. 4097 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4098 } 4099 4100 void Threads::remove(JavaThread* p) { 4101 // Extra scope needed for Thread_lock, so we can check 4102 // that we do not remove thread without safepoint code notice 4103 { MutexLocker ml(Threads_lock); 4104 4105 assert(includes(p), "p must be present"); 4106 4107 JavaThread* current = _thread_list; 4108 JavaThread* prev = NULL; 4109 4110 while (current != p) { 4111 prev = current; 4112 current = current->next(); 4113 } 4114 4115 if (prev) { 4116 prev->set_next(current->next()); 4117 } else { 4118 _thread_list = p->next(); 4119 } 4120 _number_of_threads--; 4121 oop threadObj = p->threadObj(); 4122 bool daemon = true; 4123 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4124 _number_of_non_daemon_threads--; 4125 daemon = false; 4126 4127 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4128 // on destroy_vm will wake up. 4129 if (number_of_non_daemon_threads() == 1) 4130 Threads_lock->notify_all(); 4131 } 4132 ThreadService::remove_thread(p, daemon); 4133 4134 // Make sure that safepoint code disregard this thread. This is needed since 4135 // the thread might mess around with locks after this point. This can cause it 4136 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4137 // of this thread since it is removed from the queue. 4138 p->set_terminated_value(); 4139 4140 // Now, this thread is not visible to safepoint 4141 p->set_safepoint_visible(false); 4142 // once the thread becomes safepoint invisible, we can not use its per-thread 4143 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4144 // to release its per-thread recorder here. 4145 MemTracker::thread_exiting(p); 4146 } // unlock Threads_lock 4147 4148 // Since Events::log uses a lock, we grab it outside the Threads_lock 4149 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4150 } 4151 4152 // Threads_lock must be held when this is called (or must be called during a safepoint) 4153 bool Threads::includes(JavaThread* p) { 4154 assert(Threads_lock->is_locked(), "sanity check"); 4155 ALL_JAVA_THREADS(q) { 4156 if (q == p ) { 4157 return true; 4158 } 4159 } 4160 return false; 4161 } 4162 4163 // Operations on the Threads list for GC. These are not explicitly locked, 4164 // but the garbage collector must provide a safe context for them to run. 4165 // In particular, these things should never be called when the Threads_lock 4166 // is held by some other thread. (Note: the Safepoint abstraction also 4167 // uses the Threads_lock to gurantee this property. It also makes sure that 4168 // all threads gets blocked when exiting or starting). 4169 4170 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4171 ALL_JAVA_THREADS(p) { 4172 p->oops_do(f, cld_f, cf); 4173 } 4174 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4175 } 4176 4177 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4178 // Introduce a mechanism allowing parallel threads to claim threads as 4179 // root groups. Overhead should be small enough to use all the time, 4180 // even in sequential code. 4181 SharedHeap* sh = SharedHeap::heap(); 4182 // Cannot yet substitute active_workers for n_par_threads 4183 // because of G1CollectedHeap::verify() use of 4184 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4185 // turn off parallelism in process_strong_roots while active_workers 4186 // is being used for parallelism elsewhere. 4187 bool is_par = sh->n_par_threads() > 0; 4188 assert(!is_par || 4189 (SharedHeap::heap()->n_par_threads() == 4190 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4191 int cp = SharedHeap::heap()->strong_roots_parity(); 4192 ALL_JAVA_THREADS(p) { 4193 if (p->claim_oops_do(is_par, cp)) { 4194 p->oops_do(f, cld_f, cf); 4195 } 4196 } 4197 VMThread* vmt = VMThread::vm_thread(); 4198 if (vmt->claim_oops_do(is_par, cp)) { 4199 vmt->oops_do(f, cld_f, cf); 4200 } 4201 } 4202 4203 #if INCLUDE_ALL_GCS 4204 // Used by ParallelScavenge 4205 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4206 ALL_JAVA_THREADS(p) { 4207 q->enqueue(new ThreadRootsTask(p)); 4208 } 4209 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4210 } 4211 4212 // Used by Parallel Old 4213 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4214 ALL_JAVA_THREADS(p) { 4215 q->enqueue(new ThreadRootsMarkingTask(p)); 4216 } 4217 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4218 } 4219 #endif // INCLUDE_ALL_GCS 4220 4221 void Threads::nmethods_do(CodeBlobClosure* cf) { 4222 ALL_JAVA_THREADS(p) { 4223 p->nmethods_do(cf); 4224 } 4225 VMThread::vm_thread()->nmethods_do(cf); 4226 } 4227 4228 void Threads::metadata_do(void f(Metadata*)) { 4229 ALL_JAVA_THREADS(p) { 4230 p->metadata_do(f); 4231 } 4232 } 4233 4234 void Threads::gc_epilogue() { 4235 ALL_JAVA_THREADS(p) { 4236 p->gc_epilogue(); 4237 } 4238 } 4239 4240 void Threads::gc_prologue() { 4241 ALL_JAVA_THREADS(p) { 4242 p->gc_prologue(); 4243 } 4244 } 4245 4246 void Threads::deoptimized_wrt_marked_nmethods() { 4247 ALL_JAVA_THREADS(p) { 4248 p->deoptimized_wrt_marked_nmethods(); 4249 } 4250 } 4251 4252 4253 // Get count Java threads that are waiting to enter the specified monitor. 4254 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4255 address monitor, bool doLock) { 4256 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4257 "must grab Threads_lock or be at safepoint"); 4258 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4259 4260 int i = 0; 4261 { 4262 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4263 ALL_JAVA_THREADS(p) { 4264 if (p->is_Compiler_thread()) continue; 4265 4266 address pending = (address)p->current_pending_monitor(); 4267 if (pending == monitor) { // found a match 4268 if (i < count) result->append(p); // save the first count matches 4269 i++; 4270 } 4271 } 4272 } 4273 return result; 4274 } 4275 4276 4277 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4278 assert(doLock || 4279 Threads_lock->owned_by_self() || 4280 SafepointSynchronize::is_at_safepoint(), 4281 "must grab Threads_lock or be at safepoint"); 4282 4283 // NULL owner means not locked so we can skip the search 4284 if (owner == NULL) return NULL; 4285 4286 { 4287 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4288 ALL_JAVA_THREADS(p) { 4289 // first, see if owner is the address of a Java thread 4290 if (owner == (address)p) return p; 4291 } 4292 } 4293 // Cannot assert on lack of success here since this function may be 4294 // used by code that is trying to report useful problem information 4295 // like deadlock detection. 4296 if (UseHeavyMonitors) return NULL; 4297 4298 // 4299 // If we didn't find a matching Java thread and we didn't force use of 4300 // heavyweight monitors, then the owner is the stack address of the 4301 // Lock Word in the owning Java thread's stack. 4302 // 4303 JavaThread* the_owner = NULL; 4304 { 4305 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4306 ALL_JAVA_THREADS(q) { 4307 if (q->is_lock_owned(owner)) { 4308 the_owner = q; 4309 break; 4310 } 4311 } 4312 } 4313 // cannot assert on lack of success here; see above comment 4314 return the_owner; 4315 } 4316 4317 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4318 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4319 char buf[32]; 4320 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4321 4322 st->print_cr("Full thread dump %s (%s %s):", 4323 Abstract_VM_Version::vm_name(), 4324 Abstract_VM_Version::vm_release(), 4325 Abstract_VM_Version::vm_info_string() 4326 ); 4327 st->cr(); 4328 4329 #if INCLUDE_ALL_GCS 4330 // Dump concurrent locks 4331 ConcurrentLocksDump concurrent_locks; 4332 if (print_concurrent_locks) { 4333 concurrent_locks.dump_at_safepoint(); 4334 } 4335 #endif // INCLUDE_ALL_GCS 4336 4337 ALL_JAVA_THREADS(p) { 4338 ResourceMark rm; 4339 p->print_on(st); 4340 if (print_stacks) { 4341 if (internal_format) { 4342 p->trace_stack(); 4343 } else { 4344 p->print_stack_on(st); 4345 } 4346 } 4347 st->cr(); 4348 #if INCLUDE_ALL_GCS 4349 if (print_concurrent_locks) { 4350 concurrent_locks.print_locks_on(p, st); 4351 } 4352 #endif // INCLUDE_ALL_GCS 4353 } 4354 4355 VMThread::vm_thread()->print_on(st); 4356 st->cr(); 4357 Universe::heap()->print_gc_threads_on(st); 4358 WatcherThread* wt = WatcherThread::watcher_thread(); 4359 if (wt != NULL) { 4360 wt->print_on(st); 4361 st->cr(); 4362 } 4363 CompileBroker::print_compiler_threads_on(st); 4364 st->flush(); 4365 } 4366 4367 // Threads::print_on_error() is called by fatal error handler. It's possible 4368 // that VM is not at safepoint and/or current thread is inside signal handler. 4369 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4370 // memory (even in resource area), it might deadlock the error handler. 4371 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4372 bool found_current = false; 4373 st->print_cr("Java Threads: ( => current thread )"); 4374 ALL_JAVA_THREADS(thread) { 4375 bool is_current = (current == thread); 4376 found_current = found_current || is_current; 4377 4378 st->print("%s", is_current ? "=>" : " "); 4379 4380 st->print(PTR_FORMAT, thread); 4381 st->print(" "); 4382 thread->print_on_error(st, buf, buflen); 4383 st->cr(); 4384 } 4385 st->cr(); 4386 4387 st->print_cr("Other Threads:"); 4388 if (VMThread::vm_thread()) { 4389 bool is_current = (current == VMThread::vm_thread()); 4390 found_current = found_current || is_current; 4391 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4392 4393 st->print(PTR_FORMAT, VMThread::vm_thread()); 4394 st->print(" "); 4395 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4396 st->cr(); 4397 } 4398 WatcherThread* wt = WatcherThread::watcher_thread(); 4399 if (wt != NULL) { 4400 bool is_current = (current == wt); 4401 found_current = found_current || is_current; 4402 st->print("%s", is_current ? "=>" : " "); 4403 4404 st->print(PTR_FORMAT, wt); 4405 st->print(" "); 4406 wt->print_on_error(st, buf, buflen); 4407 st->cr(); 4408 } 4409 if (!found_current) { 4410 st->cr(); 4411 st->print("=>" PTR_FORMAT " (exited) ", current); 4412 current->print_on_error(st, buf, buflen); 4413 st->cr(); 4414 } 4415 } 4416 4417 // Internal SpinLock and Mutex 4418 // Based on ParkEvent 4419 4420 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4421 // 4422 // We employ SpinLocks _only for low-contention, fixed-length 4423 // short-duration critical sections where we're concerned 4424 // about native mutex_t or HotSpot Mutex:: latency. 4425 // The mux construct provides a spin-then-block mutual exclusion 4426 // mechanism. 4427 // 4428 // Testing has shown that contention on the ListLock guarding gFreeList 4429 // is common. If we implement ListLock as a simple SpinLock it's common 4430 // for the JVM to devolve to yielding with little progress. This is true 4431 // despite the fact that the critical sections protected by ListLock are 4432 // extremely short. 4433 // 4434 // TODO-FIXME: ListLock should be of type SpinLock. 4435 // We should make this a 1st-class type, integrated into the lock 4436 // hierarchy as leaf-locks. Critically, the SpinLock structure 4437 // should have sufficient padding to avoid false-sharing and excessive 4438 // cache-coherency traffic. 4439 4440 4441 typedef volatile int SpinLockT ; 4442 4443 void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4444 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4445 return ; // normal fast-path return 4446 } 4447 4448 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4449 TEVENT (SpinAcquire - ctx) ; 4450 int ctr = 0 ; 4451 int Yields = 0 ; 4452 for (;;) { 4453 while (*adr != 0) { 4454 ++ctr ; 4455 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4456 if (Yields > 5) { 4457 // Consider using a simple NakedSleep() instead. 4458 // Then SpinAcquire could be called by non-JVM threads 4459 Thread::current()->_ParkEvent->park(1) ; 4460 } else { 4461 os::NakedYield() ; 4462 ++Yields ; 4463 } 4464 } else { 4465 SpinPause() ; 4466 } 4467 } 4468 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4469 } 4470 } 4471 4472 void Thread::SpinRelease (volatile int * adr) { 4473 assert (*adr != 0, "invariant") ; 4474 OrderAccess::fence() ; // guarantee at least release consistency. 4475 // Roach-motel semantics. 4476 // It's safe if subsequent LDs and STs float "up" into the critical section, 4477 // but prior LDs and STs within the critical section can't be allowed 4478 // to reorder or float past the ST that releases the lock. 4479 *adr = 0 ; 4480 } 4481 4482 // muxAcquire and muxRelease: 4483 // 4484 // * muxAcquire and muxRelease support a single-word lock-word construct. 4485 // The LSB of the word is set IFF the lock is held. 4486 // The remainder of the word points to the head of a singly-linked list 4487 // of threads blocked on the lock. 4488 // 4489 // * The current implementation of muxAcquire-muxRelease uses its own 4490 // dedicated Thread._MuxEvent instance. If we're interested in 4491 // minimizing the peak number of extant ParkEvent instances then 4492 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4493 // as certain invariants were satisfied. Specifically, care would need 4494 // to be taken with regards to consuming unpark() "permits". 4495 // A safe rule of thumb is that a thread would never call muxAcquire() 4496 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4497 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4498 // consume an unpark() permit intended for monitorenter, for instance. 4499 // One way around this would be to widen the restricted-range semaphore 4500 // implemented in park(). Another alternative would be to provide 4501 // multiple instances of the PlatformEvent() for each thread. One 4502 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4503 // 4504 // * Usage: 4505 // -- Only as leaf locks 4506 // -- for short-term locking only as muxAcquire does not perform 4507 // thread state transitions. 4508 // 4509 // Alternatives: 4510 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4511 // but with parking or spin-then-park instead of pure spinning. 4512 // * Use Taura-Oyama-Yonenzawa locks. 4513 // * It's possible to construct a 1-0 lock if we encode the lockword as 4514 // (List,LockByte). Acquire will CAS the full lockword while Release 4515 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4516 // acquiring threads use timers (ParkTimed) to detect and recover from 4517 // the stranding window. Thread/Node structures must be aligned on 256-byte 4518 // boundaries by using placement-new. 4519 // * Augment MCS with advisory back-link fields maintained with CAS(). 4520 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4521 // The validity of the backlinks must be ratified before we trust the value. 4522 // If the backlinks are invalid the exiting thread must back-track through the 4523 // the forward links, which are always trustworthy. 4524 // * Add a successor indication. The LockWord is currently encoded as 4525 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4526 // to provide the usual futile-wakeup optimization. 4527 // See RTStt for details. 4528 // * Consider schedctl.sc_nopreempt to cover the critical section. 4529 // 4530 4531 4532 typedef volatile intptr_t MutexT ; // Mux Lock-word 4533 enum MuxBits { LOCKBIT = 1 } ; 4534 4535 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4536 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4537 if (w == 0) return ; 4538 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4539 return ; 4540 } 4541 4542 TEVENT (muxAcquire - Contention) ; 4543 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4544 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4545 for (;;) { 4546 int its = (os::is_MP() ? 100 : 0) + 1 ; 4547 4548 // Optional spin phase: spin-then-park strategy 4549 while (--its >= 0) { 4550 w = *Lock ; 4551 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4552 return ; 4553 } 4554 } 4555 4556 Self->reset() ; 4557 Self->OnList = intptr_t(Lock) ; 4558 // The following fence() isn't _strictly necessary as the subsequent 4559 // CAS() both serializes execution and ratifies the fetched *Lock value. 4560 OrderAccess::fence(); 4561 for (;;) { 4562 w = *Lock ; 4563 if ((w & LOCKBIT) == 0) { 4564 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4565 Self->OnList = 0 ; // hygiene - allows stronger asserts 4566 return ; 4567 } 4568 continue ; // Interference -- *Lock changed -- Just retry 4569 } 4570 assert (w & LOCKBIT, "invariant") ; 4571 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4572 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4573 } 4574 4575 while (Self->OnList != 0) { 4576 Self->park() ; 4577 } 4578 } 4579 } 4580 4581 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4582 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4583 if (w == 0) return ; 4584 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4585 return ; 4586 } 4587 4588 TEVENT (muxAcquire - Contention) ; 4589 ParkEvent * ReleaseAfter = NULL ; 4590 if (ev == NULL) { 4591 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4592 } 4593 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4594 for (;;) { 4595 guarantee (ev->OnList == 0, "invariant") ; 4596 int its = (os::is_MP() ? 100 : 0) + 1 ; 4597 4598 // Optional spin phase: spin-then-park strategy 4599 while (--its >= 0) { 4600 w = *Lock ; 4601 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4602 if (ReleaseAfter != NULL) { 4603 ParkEvent::Release (ReleaseAfter) ; 4604 } 4605 return ; 4606 } 4607 } 4608 4609 ev->reset() ; 4610 ev->OnList = intptr_t(Lock) ; 4611 // The following fence() isn't _strictly necessary as the subsequent 4612 // CAS() both serializes execution and ratifies the fetched *Lock value. 4613 OrderAccess::fence(); 4614 for (;;) { 4615 w = *Lock ; 4616 if ((w & LOCKBIT) == 0) { 4617 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4618 ev->OnList = 0 ; 4619 // We call ::Release while holding the outer lock, thus 4620 // artificially lengthening the critical section. 4621 // Consider deferring the ::Release() until the subsequent unlock(), 4622 // after we've dropped the outer lock. 4623 if (ReleaseAfter != NULL) { 4624 ParkEvent::Release (ReleaseAfter) ; 4625 } 4626 return ; 4627 } 4628 continue ; // Interference -- *Lock changed -- Just retry 4629 } 4630 assert (w & LOCKBIT, "invariant") ; 4631 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4632 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4633 } 4634 4635 while (ev->OnList != 0) { 4636 ev->park() ; 4637 } 4638 } 4639 } 4640 4641 // Release() must extract a successor from the list and then wake that thread. 4642 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4643 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4644 // Release() would : 4645 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4646 // (B) Extract a successor from the private list "in-hand" 4647 // (C) attempt to CAS() the residual back into *Lock over null. 4648 // If there were any newly arrived threads and the CAS() would fail. 4649 // In that case Release() would detach the RATs, re-merge the list in-hand 4650 // with the RATs and repeat as needed. Alternately, Release() might 4651 // detach and extract a successor, but then pass the residual list to the wakee. 4652 // The wakee would be responsible for reattaching and remerging before it 4653 // competed for the lock. 4654 // 4655 // Both "pop" and DMR are immune from ABA corruption -- there can be 4656 // multiple concurrent pushers, but only one popper or detacher. 4657 // This implementation pops from the head of the list. This is unfair, 4658 // but tends to provide excellent throughput as hot threads remain hot. 4659 // (We wake recently run threads first). 4660 4661 void Thread::muxRelease (volatile intptr_t * Lock) { 4662 for (;;) { 4663 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4664 assert (w & LOCKBIT, "invariant") ; 4665 if (w == LOCKBIT) return ; 4666 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4667 assert (List != NULL, "invariant") ; 4668 assert (List->OnList == intptr_t(Lock), "invariant") ; 4669 ParkEvent * nxt = List->ListNext ; 4670 4671 // The following CAS() releases the lock and pops the head element. 4672 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4673 continue ; 4674 } 4675 List->OnList = 0 ; 4676 OrderAccess::fence() ; 4677 List->unpark () ; 4678 return ; 4679 } 4680 } 4681 4682 4683 void Threads::verify() { 4684 ALL_JAVA_THREADS(p) { 4685 p->verify(); 4686 } 4687 VMThread* thread = VMThread::vm_thread(); 4688 if (thread != NULL) thread->verify(); 4689 }