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/traceEventTypes.hpp" 81 #include "utilities/defaultStream.hpp" 82 #include "utilities/dtrace.hpp" 83 #include "utilities/events.hpp" 84 #include "utilities/preserveException.hpp" 85 #include "utilities/macros.hpp" 86 #ifdef TARGET_OS_FAMILY_linux 87 # include "os_linux.inline.hpp" 88 #endif 89 #ifdef TARGET_OS_FAMILY_solaris 90 # include "os_solaris.inline.hpp" 91 #endif 92 #ifdef TARGET_OS_FAMILY_windows 93 # include "os_windows.inline.hpp" 94 #endif 95 #ifdef TARGET_OS_FAMILY_bsd 96 # include "os_bsd.inline.hpp" 97 #endif 98 #if INCLUDE_ALL_GCS 99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 101 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 102 #endif // INCLUDE_ALL_GCS 103 #ifdef COMPILER1 104 #include "c1/c1_Compiler.hpp" 105 #endif 106 #ifdef COMPILER2 107 #include "opto/c2compiler.hpp" 108 #include "opto/idealGraphPrinter.hpp" 109 #endif 110 111 #ifdef DTRACE_ENABLED 112 113 // Only bother with this argument setup if dtrace is available 114 115 #ifndef USDT2 116 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 117 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 118 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 119 intptr_t, intptr_t, bool); 120 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 121 intptr_t, intptr_t, bool); 122 123 #define DTRACE_THREAD_PROBE(probe, javathread) \ 124 { \ 125 ResourceMark rm(this); \ 126 int len = 0; \ 127 const char* name = (javathread)->get_thread_name(); \ 128 len = strlen(name); \ 129 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 130 name, len, \ 131 java_lang_Thread::thread_id((javathread)->threadObj()), \ 132 (javathread)->osthread()->thread_id(), \ 133 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 134 } 135 136 #else /* USDT2 */ 137 138 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START 139 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP 140 141 #define DTRACE_THREAD_PROBE(probe, javathread) \ 142 { \ 143 ResourceMark rm(this); \ 144 int len = 0; \ 145 const char* name = (javathread)->get_thread_name(); \ 146 len = strlen(name); \ 147 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 148 (char *) name, len, \ 149 java_lang_Thread::thread_id((javathread)->threadObj()), \ 150 (uintptr_t) (javathread)->osthread()->thread_id(), \ 151 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 152 } 153 154 #endif /* USDT2 */ 155 156 #else // ndef DTRACE_ENABLED 157 158 #define DTRACE_THREAD_PROBE(probe, javathread) 159 160 #endif // ndef DTRACE_ENABLED 161 162 163 // Class hierarchy 164 // - Thread 165 // - VMThread 166 // - WatcherThread 167 // - ConcurrentMarkSweepThread 168 // - JavaThread 169 // - CompilerThread 170 171 // ======= Thread ======== 172 // Support for forcing alignment of thread objects for biased locking 173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 174 if (UseBiasedLocking) { 175 const int alignment = markOopDesc::biased_lock_alignment; 176 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 178 : AllocateHeap(aligned_size, flags, CURRENT_PC, 179 AllocFailStrategy::RETURN_NULL); 180 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 183 "JavaThread alignment code overflowed allocated storage"); 184 if (TraceBiasedLocking) { 185 if (aligned_addr != real_malloc_addr) 186 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 187 real_malloc_addr, aligned_addr); 188 } 189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 190 return aligned_addr; 191 } else { 192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 194 } 195 } 196 197 void Thread::operator delete(void* p) { 198 if (UseBiasedLocking) { 199 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 200 FreeHeap(real_malloc_addr, mtThread); 201 } else { 202 FreeHeap(p, mtThread); 203 } 204 } 205 206 207 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 208 // JavaThread 209 210 211 Thread::Thread() { 212 // stack and get_thread 213 set_stack_base(NULL); 214 set_stack_size(0); 215 set_self_raw_id(0); 216 set_lgrp_id(-1); 217 218 // allocated data structures 219 set_osthread(NULL); 220 set_resource_area(new (mtThread)ResourceArea()); 221 set_handle_area(new (mtThread) HandleArea(NULL)); 222 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(300, true)); 223 set_active_handles(NULL); 224 set_free_handle_block(NULL); 225 set_last_handle_mark(NULL); 226 227 // This initial value ==> never claimed. 228 _oops_do_parity = 0; 229 230 // the handle mark links itself to last_handle_mark 231 new HandleMark(this); 232 233 // plain initialization 234 debug_only(_owned_locks = NULL;) 235 debug_only(_allow_allocation_count = 0;) 236 NOT_PRODUCT(_allow_safepoint_count = 0;) 237 NOT_PRODUCT(_skip_gcalot = false;) 238 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;) 239 _jvmti_env_iteration_count = 0; 240 set_allocated_bytes(0); 241 set_trace_buffer(NULL); 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 EVENT_BEGIN(TraceEventThreadStart, event); 1663 EVENT_COMMIT(event, 1664 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj()))); 1665 1666 // We call another function to do the rest so we are sure that the stack addresses used 1667 // from there will be lower than the stack base just computed 1668 thread_main_inner(); 1669 1670 // Note, thread is no longer valid at this point! 1671 } 1672 1673 1674 void JavaThread::thread_main_inner() { 1675 assert(JavaThread::current() == this, "sanity check"); 1676 assert(this->threadObj() != NULL, "just checking"); 1677 1678 // Execute thread entry point unless this thread has a pending exception 1679 // or has been stopped before starting. 1680 // Note: Due to JVM_StopThread we can have pending exceptions already! 1681 if (!this->has_pending_exception() && 1682 !java_lang_Thread::is_stillborn(this->threadObj())) { 1683 { 1684 ResourceMark rm(this); 1685 this->set_native_thread_name(this->get_thread_name()); 1686 } 1687 HandleMark hm(this); 1688 this->entry_point()(this, this); 1689 } 1690 1691 DTRACE_THREAD_PROBE(stop, this); 1692 1693 this->exit(false); 1694 delete this; 1695 } 1696 1697 1698 static void ensure_join(JavaThread* thread) { 1699 // We do not need to grap the Threads_lock, since we are operating on ourself. 1700 Handle threadObj(thread, thread->threadObj()); 1701 assert(threadObj.not_null(), "java thread object must exist"); 1702 ObjectLocker lock(threadObj, thread); 1703 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1704 thread->clear_pending_exception(); 1705 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1706 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1707 // Clear the native thread instance - this makes isAlive return false and allows the join() 1708 // to complete once we've done the notify_all below 1709 java_lang_Thread::set_thread(threadObj(), NULL); 1710 lock.notify_all(thread); 1711 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1712 thread->clear_pending_exception(); 1713 } 1714 1715 1716 // For any new cleanup additions, please check to see if they need to be applied to 1717 // cleanup_failed_attach_current_thread as well. 1718 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1719 assert(this == JavaThread::current(), "thread consistency check"); 1720 1721 HandleMark hm(this); 1722 Handle uncaught_exception(this, this->pending_exception()); 1723 this->clear_pending_exception(); 1724 Handle threadObj(this, this->threadObj()); 1725 assert(threadObj.not_null(), "Java thread object should be created"); 1726 1727 if (get_thread_profiler() != NULL) { 1728 get_thread_profiler()->disengage(); 1729 ResourceMark rm; 1730 get_thread_profiler()->print(get_thread_name()); 1731 } 1732 1733 1734 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1735 { 1736 EXCEPTION_MARK; 1737 1738 CLEAR_PENDING_EXCEPTION; 1739 } 1740 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1741 // has to be fixed by a runtime query method 1742 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1743 // JSR-166: change call from from ThreadGroup.uncaughtException to 1744 // java.lang.Thread.dispatchUncaughtException 1745 if (uncaught_exception.not_null()) { 1746 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1747 { 1748 EXCEPTION_MARK; 1749 // Check if the method Thread.dispatchUncaughtException() exists. If so 1750 // call it. Otherwise we have an older library without the JSR-166 changes, 1751 // so call ThreadGroup.uncaughtException() 1752 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1753 CallInfo callinfo; 1754 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1755 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1756 vmSymbols::dispatchUncaughtException_name(), 1757 vmSymbols::throwable_void_signature(), 1758 KlassHandle(), false, false, THREAD); 1759 CLEAR_PENDING_EXCEPTION; 1760 methodHandle method = callinfo.selected_method(); 1761 if (method.not_null()) { 1762 JavaValue result(T_VOID); 1763 JavaCalls::call_virtual(&result, 1764 threadObj, thread_klass, 1765 vmSymbols::dispatchUncaughtException_name(), 1766 vmSymbols::throwable_void_signature(), 1767 uncaught_exception, 1768 THREAD); 1769 } else { 1770 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1771 JavaValue result(T_VOID); 1772 JavaCalls::call_virtual(&result, 1773 group, thread_group, 1774 vmSymbols::uncaughtException_name(), 1775 vmSymbols::thread_throwable_void_signature(), 1776 threadObj, // Arg 1 1777 uncaught_exception, // Arg 2 1778 THREAD); 1779 } 1780 if (HAS_PENDING_EXCEPTION) { 1781 ResourceMark rm(this); 1782 jio_fprintf(defaultStream::error_stream(), 1783 "\nException: %s thrown from the UncaughtExceptionHandler" 1784 " in thread \"%s\"\n", 1785 pending_exception()->klass()->external_name(), 1786 get_thread_name()); 1787 CLEAR_PENDING_EXCEPTION; 1788 } 1789 } 1790 } 1791 1792 // Called before the java thread exit since we want to read info 1793 // from java_lang_Thread object 1794 EVENT_BEGIN(TraceEventThreadEnd, event); 1795 EVENT_COMMIT(event, 1796 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj()))); 1797 1798 // Call after last event on thread 1799 EVENT_THREAD_EXIT(this); 1800 1801 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1802 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1803 // is deprecated anyhow. 1804 { int count = 3; 1805 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1806 EXCEPTION_MARK; 1807 JavaValue result(T_VOID); 1808 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1809 JavaCalls::call_virtual(&result, 1810 threadObj, thread_klass, 1811 vmSymbols::exit_method_name(), 1812 vmSymbols::void_method_signature(), 1813 THREAD); 1814 CLEAR_PENDING_EXCEPTION; 1815 } 1816 } 1817 1818 // notify JVMTI 1819 if (JvmtiExport::should_post_thread_life()) { 1820 JvmtiExport::post_thread_end(this); 1821 } 1822 1823 // We have notified the agents that we are exiting, before we go on, 1824 // we must check for a pending external suspend request and honor it 1825 // in order to not surprise the thread that made the suspend request. 1826 while (true) { 1827 { 1828 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1829 if (!is_external_suspend()) { 1830 set_terminated(_thread_exiting); 1831 ThreadService::current_thread_exiting(this); 1832 break; 1833 } 1834 // Implied else: 1835 // Things get a little tricky here. We have a pending external 1836 // suspend request, but we are holding the SR_lock so we 1837 // can't just self-suspend. So we temporarily drop the lock 1838 // and then self-suspend. 1839 } 1840 1841 ThreadBlockInVM tbivm(this); 1842 java_suspend_self(); 1843 1844 // We're done with this suspend request, but we have to loop around 1845 // and check again. Eventually we will get SR_lock without a pending 1846 // external suspend request and will be able to mark ourselves as 1847 // exiting. 1848 } 1849 // no more external suspends are allowed at this point 1850 } else { 1851 // before_exit() has already posted JVMTI THREAD_END events 1852 } 1853 1854 // Notify waiters on thread object. This has to be done after exit() is called 1855 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1856 // group should have the destroyed bit set before waiters are notified). 1857 ensure_join(this); 1858 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1859 1860 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1861 // held by this thread must be released. A detach operation must only 1862 // get here if there are no Java frames on the stack. Therefore, any 1863 // owned monitors at this point MUST be JNI-acquired monitors which are 1864 // pre-inflated and in the monitor cache. 1865 // 1866 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1867 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1868 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1869 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1870 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1871 } 1872 1873 // These things needs to be done while we are still a Java Thread. Make sure that thread 1874 // is in a consistent state, in case GC happens 1875 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1876 1877 if (active_handles() != NULL) { 1878 JNIHandleBlock* block = active_handles(); 1879 set_active_handles(NULL); 1880 JNIHandleBlock::release_block(block); 1881 } 1882 1883 if (free_handle_block() != NULL) { 1884 JNIHandleBlock* block = free_handle_block(); 1885 set_free_handle_block(NULL); 1886 JNIHandleBlock::release_block(block); 1887 } 1888 1889 // These have to be removed while this is still a valid thread. 1890 remove_stack_guard_pages(); 1891 1892 if (UseTLAB) { 1893 tlab().make_parsable(true); // retire TLAB 1894 } 1895 1896 if (JvmtiEnv::environments_might_exist()) { 1897 JvmtiExport::cleanup_thread(this); 1898 } 1899 1900 // We must flush any deferred card marks before removing a thread from 1901 // the list of active threads. 1902 Universe::heap()->flush_deferred_store_barrier(this); 1903 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1904 1905 #if INCLUDE_ALL_GCS 1906 // We must flush the G1-related buffers before removing a thread 1907 // from the list of active threads. We must do this after any deferred 1908 // card marks have been flushed (above) so that any entries that are 1909 // added to the thread's dirty card queue as a result are not lost. 1910 if (UseG1GC) { 1911 flush_barrier_queues(); 1912 } 1913 #endif // INCLUDE_ALL_GCS 1914 1915 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1916 Threads::remove(this); 1917 } 1918 1919 #if INCLUDE_ALL_GCS 1920 // Flush G1-related queues. 1921 void JavaThread::flush_barrier_queues() { 1922 satb_mark_queue().flush(); 1923 dirty_card_queue().flush(); 1924 } 1925 1926 void JavaThread::initialize_queues() { 1927 assert(!SafepointSynchronize::is_at_safepoint(), 1928 "we should not be at a safepoint"); 1929 1930 ObjPtrQueue& satb_queue = satb_mark_queue(); 1931 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1932 // The SATB queue should have been constructed with its active 1933 // field set to false. 1934 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1935 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1936 // If we are creating the thread during a marking cycle, we should 1937 // set the active field of the SATB queue to true. 1938 if (satb_queue_set.is_active()) { 1939 satb_queue.set_active(true); 1940 } 1941 1942 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1943 // The dirty card queue should have been constructed with its 1944 // active field set to true. 1945 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1946 } 1947 #endif // INCLUDE_ALL_GCS 1948 1949 void JavaThread::cleanup_failed_attach_current_thread() { 1950 if (get_thread_profiler() != NULL) { 1951 get_thread_profiler()->disengage(); 1952 ResourceMark rm; 1953 get_thread_profiler()->print(get_thread_name()); 1954 } 1955 1956 if (active_handles() != NULL) { 1957 JNIHandleBlock* block = active_handles(); 1958 set_active_handles(NULL); 1959 JNIHandleBlock::release_block(block); 1960 } 1961 1962 if (free_handle_block() != NULL) { 1963 JNIHandleBlock* block = free_handle_block(); 1964 set_free_handle_block(NULL); 1965 JNIHandleBlock::release_block(block); 1966 } 1967 1968 // These have to be removed while this is still a valid thread. 1969 remove_stack_guard_pages(); 1970 1971 if (UseTLAB) { 1972 tlab().make_parsable(true); // retire TLAB, if any 1973 } 1974 1975 #if INCLUDE_ALL_GCS 1976 if (UseG1GC) { 1977 flush_barrier_queues(); 1978 } 1979 #endif // INCLUDE_ALL_GCS 1980 1981 Threads::remove(this); 1982 delete this; 1983 } 1984 1985 1986 1987 1988 JavaThread* JavaThread::active() { 1989 Thread* thread = ThreadLocalStorage::thread(); 1990 assert(thread != NULL, "just checking"); 1991 if (thread->is_Java_thread()) { 1992 return (JavaThread*) thread; 1993 } else { 1994 assert(thread->is_VM_thread(), "this must be a vm thread"); 1995 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1996 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1997 assert(ret->is_Java_thread(), "must be a Java thread"); 1998 return ret; 1999 } 2000 } 2001 2002 bool JavaThread::is_lock_owned(address adr) const { 2003 if (Thread::is_lock_owned(adr)) return true; 2004 2005 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2006 if (chunk->contains(adr)) return true; 2007 } 2008 2009 return false; 2010 } 2011 2012 2013 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2014 chunk->set_next(monitor_chunks()); 2015 set_monitor_chunks(chunk); 2016 } 2017 2018 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2019 guarantee(monitor_chunks() != NULL, "must be non empty"); 2020 if (monitor_chunks() == chunk) { 2021 set_monitor_chunks(chunk->next()); 2022 } else { 2023 MonitorChunk* prev = monitor_chunks(); 2024 while (prev->next() != chunk) prev = prev->next(); 2025 prev->set_next(chunk->next()); 2026 } 2027 } 2028 2029 // JVM support. 2030 2031 // Note: this function shouldn't block if it's called in 2032 // _thread_in_native_trans state (such as from 2033 // check_special_condition_for_native_trans()). 2034 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2035 2036 if (has_last_Java_frame() && has_async_condition()) { 2037 // If we are at a polling page safepoint (not a poll return) 2038 // then we must defer async exception because live registers 2039 // will be clobbered by the exception path. Poll return is 2040 // ok because the call we a returning from already collides 2041 // with exception handling registers and so there is no issue. 2042 // (The exception handling path kills call result registers but 2043 // this is ok since the exception kills the result anyway). 2044 2045 if (is_at_poll_safepoint()) { 2046 // if the code we are returning to has deoptimized we must defer 2047 // the exception otherwise live registers get clobbered on the 2048 // exception path before deoptimization is able to retrieve them. 2049 // 2050 RegisterMap map(this, false); 2051 frame caller_fr = last_frame().sender(&map); 2052 assert(caller_fr.is_compiled_frame(), "what?"); 2053 if (caller_fr.is_deoptimized_frame()) { 2054 if (TraceExceptions) { 2055 ResourceMark rm; 2056 tty->print_cr("deferred async exception at compiled safepoint"); 2057 } 2058 return; 2059 } 2060 } 2061 } 2062 2063 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2064 if (condition == _no_async_condition) { 2065 // Conditions have changed since has_special_runtime_exit_condition() 2066 // was called: 2067 // - if we were here only because of an external suspend request, 2068 // then that was taken care of above (or cancelled) so we are done 2069 // - if we were here because of another async request, then it has 2070 // been cleared between the has_special_runtime_exit_condition() 2071 // and now so again we are done 2072 return; 2073 } 2074 2075 // Check for pending async. exception 2076 if (_pending_async_exception != NULL) { 2077 // Only overwrite an already pending exception, if it is not a threadDeath. 2078 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2079 2080 // We cannot call Exceptions::_throw(...) here because we cannot block 2081 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2082 2083 if (TraceExceptions) { 2084 ResourceMark rm; 2085 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2086 if (has_last_Java_frame() ) { 2087 frame f = last_frame(); 2088 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2089 } 2090 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2091 } 2092 _pending_async_exception = NULL; 2093 clear_has_async_exception(); 2094 } 2095 } 2096 2097 if (check_unsafe_error && 2098 condition == _async_unsafe_access_error && !has_pending_exception()) { 2099 condition = _no_async_condition; // done 2100 switch (thread_state()) { 2101 case _thread_in_vm: 2102 { 2103 JavaThread* THREAD = this; 2104 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2105 } 2106 case _thread_in_native: 2107 { 2108 ThreadInVMfromNative tiv(this); 2109 JavaThread* THREAD = this; 2110 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2111 } 2112 case _thread_in_Java: 2113 { 2114 ThreadInVMfromJava tiv(this); 2115 JavaThread* THREAD = this; 2116 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2117 } 2118 default: 2119 ShouldNotReachHere(); 2120 } 2121 } 2122 2123 assert(condition == _no_async_condition || has_pending_exception() || 2124 (!check_unsafe_error && condition == _async_unsafe_access_error), 2125 "must have handled the async condition, if no exception"); 2126 } 2127 2128 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2129 // 2130 // Check for pending external suspend. Internal suspend requests do 2131 // not use handle_special_runtime_exit_condition(). 2132 // If JNIEnv proxies are allowed, don't self-suspend if the target 2133 // thread is not the current thread. In older versions of jdbx, jdbx 2134 // threads could call into the VM with another thread's JNIEnv so we 2135 // can be here operating on behalf of a suspended thread (4432884). 2136 bool do_self_suspend = is_external_suspend_with_lock(); 2137 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2138 // 2139 // Because thread is external suspended the safepoint code will count 2140 // thread as at a safepoint. This can be odd because we can be here 2141 // as _thread_in_Java which would normally transition to _thread_blocked 2142 // at a safepoint. We would like to mark the thread as _thread_blocked 2143 // before calling java_suspend_self like all other callers of it but 2144 // we must then observe proper safepoint protocol. (We can't leave 2145 // _thread_blocked with a safepoint in progress). However we can be 2146 // here as _thread_in_native_trans so we can't use a normal transition 2147 // constructor/destructor pair because they assert on that type of 2148 // transition. We could do something like: 2149 // 2150 // JavaThreadState state = thread_state(); 2151 // set_thread_state(_thread_in_vm); 2152 // { 2153 // ThreadBlockInVM tbivm(this); 2154 // java_suspend_self() 2155 // } 2156 // set_thread_state(_thread_in_vm_trans); 2157 // if (safepoint) block; 2158 // set_thread_state(state); 2159 // 2160 // but that is pretty messy. Instead we just go with the way the 2161 // code has worked before and note that this is the only path to 2162 // java_suspend_self that doesn't put the thread in _thread_blocked 2163 // mode. 2164 2165 frame_anchor()->make_walkable(this); 2166 java_suspend_self(); 2167 2168 // We might be here for reasons in addition to the self-suspend request 2169 // so check for other async requests. 2170 } 2171 2172 if (check_asyncs) { 2173 check_and_handle_async_exceptions(); 2174 } 2175 } 2176 2177 void JavaThread::send_thread_stop(oop java_throwable) { 2178 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2179 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2180 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2181 2182 // Do not throw asynchronous exceptions against the compiler thread 2183 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2184 if (is_Compiler_thread()) return; 2185 2186 { 2187 // Actually throw the Throwable against the target Thread - however 2188 // only if there is no thread death exception installed already. 2189 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2190 // If the topmost frame is a runtime stub, then we are calling into 2191 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2192 // must deoptimize the caller before continuing, as the compiled exception handler table 2193 // may not be valid 2194 if (has_last_Java_frame()) { 2195 frame f = last_frame(); 2196 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2197 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2198 RegisterMap reg_map(this, UseBiasedLocking); 2199 frame compiled_frame = f.sender(®_map); 2200 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2201 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2202 } 2203 } 2204 } 2205 2206 // Set async. pending exception in thread. 2207 set_pending_async_exception(java_throwable); 2208 2209 if (TraceExceptions) { 2210 ResourceMark rm; 2211 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2212 } 2213 // for AbortVMOnException flag 2214 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2215 } 2216 } 2217 2218 2219 // Interrupt thread so it will wake up from a potential wait() 2220 Thread::interrupt(this); 2221 } 2222 2223 // External suspension mechanism. 2224 // 2225 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2226 // to any VM_locks and it is at a transition 2227 // Self-suspension will happen on the transition out of the vm. 2228 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2229 // 2230 // Guarantees on return: 2231 // + Target thread will not execute any new bytecode (that's why we need to 2232 // force a safepoint) 2233 // + Target thread will not enter any new monitors 2234 // 2235 void JavaThread::java_suspend() { 2236 { MutexLocker mu(Threads_lock); 2237 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2238 return; 2239 } 2240 } 2241 2242 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2243 if (!is_external_suspend()) { 2244 // a racing resume has cancelled us; bail out now 2245 return; 2246 } 2247 2248 // suspend is done 2249 uint32_t debug_bits = 0; 2250 // Warning: is_ext_suspend_completed() may temporarily drop the 2251 // SR_lock to allow the thread to reach a stable thread state if 2252 // it is currently in a transient thread state. 2253 if (is_ext_suspend_completed(false /* !called_by_wait */, 2254 SuspendRetryDelay, &debug_bits) ) { 2255 return; 2256 } 2257 } 2258 2259 VM_ForceSafepoint vm_suspend; 2260 VMThread::execute(&vm_suspend); 2261 } 2262 2263 // Part II of external suspension. 2264 // A JavaThread self suspends when it detects a pending external suspend 2265 // request. This is usually on transitions. It is also done in places 2266 // where continuing to the next transition would surprise the caller, 2267 // e.g., monitor entry. 2268 // 2269 // Returns the number of times that the thread self-suspended. 2270 // 2271 // Note: DO NOT call java_suspend_self() when you just want to block current 2272 // thread. java_suspend_self() is the second stage of cooperative 2273 // suspension for external suspend requests and should only be used 2274 // to complete an external suspend request. 2275 // 2276 int JavaThread::java_suspend_self() { 2277 int ret = 0; 2278 2279 // we are in the process of exiting so don't suspend 2280 if (is_exiting()) { 2281 clear_external_suspend(); 2282 return ret; 2283 } 2284 2285 assert(_anchor.walkable() || 2286 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2287 "must have walkable stack"); 2288 2289 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2290 2291 assert(!this->is_ext_suspended(), 2292 "a thread trying to self-suspend should not already be suspended"); 2293 2294 if (this->is_suspend_equivalent()) { 2295 // If we are self-suspending as a result of the lifting of a 2296 // suspend equivalent condition, then the suspend_equivalent 2297 // flag is not cleared until we set the ext_suspended flag so 2298 // that wait_for_ext_suspend_completion() returns consistent 2299 // results. 2300 this->clear_suspend_equivalent(); 2301 } 2302 2303 // A racing resume may have cancelled us before we grabbed SR_lock 2304 // above. Or another external suspend request could be waiting for us 2305 // by the time we return from SR_lock()->wait(). The thread 2306 // that requested the suspension may already be trying to walk our 2307 // stack and if we return now, we can change the stack out from under 2308 // it. This would be a "bad thing (TM)" and cause the stack walker 2309 // to crash. We stay self-suspended until there are no more pending 2310 // external suspend requests. 2311 while (is_external_suspend()) { 2312 ret++; 2313 this->set_ext_suspended(); 2314 2315 // _ext_suspended flag is cleared by java_resume() 2316 while (is_ext_suspended()) { 2317 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2318 } 2319 } 2320 2321 return ret; 2322 } 2323 2324 #ifdef ASSERT 2325 // verify the JavaThread has not yet been published in the Threads::list, and 2326 // hence doesn't need protection from concurrent access at this stage 2327 void JavaThread::verify_not_published() { 2328 if (!Threads_lock->owned_by_self()) { 2329 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2330 assert( !Threads::includes(this), 2331 "java thread shouldn't have been published yet!"); 2332 } 2333 else { 2334 assert( !Threads::includes(this), 2335 "java thread shouldn't have been published yet!"); 2336 } 2337 } 2338 #endif 2339 2340 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2341 // progress or when _suspend_flags is non-zero. 2342 // Current thread needs to self-suspend if there is a suspend request and/or 2343 // block if a safepoint is in progress. 2344 // Async exception ISN'T checked. 2345 // Note only the ThreadInVMfromNative transition can call this function 2346 // directly and when thread state is _thread_in_native_trans 2347 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2348 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2349 2350 JavaThread *curJT = JavaThread::current(); 2351 bool do_self_suspend = thread->is_external_suspend(); 2352 2353 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2354 2355 // If JNIEnv proxies are allowed, don't self-suspend if the target 2356 // thread is not the current thread. In older versions of jdbx, jdbx 2357 // threads could call into the VM with another thread's JNIEnv so we 2358 // can be here operating on behalf of a suspended thread (4432884). 2359 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2360 JavaThreadState state = thread->thread_state(); 2361 2362 // We mark this thread_blocked state as a suspend-equivalent so 2363 // that a caller to is_ext_suspend_completed() won't be confused. 2364 // The suspend-equivalent state is cleared by java_suspend_self(). 2365 thread->set_suspend_equivalent(); 2366 2367 // If the safepoint code sees the _thread_in_native_trans state, it will 2368 // wait until the thread changes to other thread state. There is no 2369 // guarantee on how soon we can obtain the SR_lock and complete the 2370 // self-suspend request. It would be a bad idea to let safepoint wait for 2371 // too long. Temporarily change the state to _thread_blocked to 2372 // let the VM thread know that this thread is ready for GC. The problem 2373 // of changing thread state is that safepoint could happen just after 2374 // java_suspend_self() returns after being resumed, and VM thread will 2375 // see the _thread_blocked state. We must check for safepoint 2376 // after restoring the state and make sure we won't leave while a safepoint 2377 // is in progress. 2378 thread->set_thread_state(_thread_blocked); 2379 thread->java_suspend_self(); 2380 thread->set_thread_state(state); 2381 // Make sure new state is seen by VM thread 2382 if (os::is_MP()) { 2383 if (UseMembar) { 2384 // Force a fence between the write above and read below 2385 OrderAccess::fence(); 2386 } else { 2387 // Must use this rather than serialization page in particular on Windows 2388 InterfaceSupport::serialize_memory(thread); 2389 } 2390 } 2391 } 2392 2393 if (SafepointSynchronize::do_call_back()) { 2394 // If we are safepointing, then block the caller which may not be 2395 // the same as the target thread (see above). 2396 SafepointSynchronize::block(curJT); 2397 } 2398 2399 if (thread->is_deopt_suspend()) { 2400 thread->clear_deopt_suspend(); 2401 RegisterMap map(thread, false); 2402 frame f = thread->last_frame(); 2403 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2404 f = f.sender(&map); 2405 } 2406 if (f.id() == thread->must_deopt_id()) { 2407 thread->clear_must_deopt_id(); 2408 f.deoptimize(thread); 2409 } else { 2410 fatal("missed deoptimization!"); 2411 } 2412 } 2413 } 2414 2415 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2416 // progress or when _suspend_flags is non-zero. 2417 // Current thread needs to self-suspend if there is a suspend request and/or 2418 // block if a safepoint is in progress. 2419 // Also check for pending async exception (not including unsafe access error). 2420 // Note only the native==>VM/Java barriers can call this function and when 2421 // thread state is _thread_in_native_trans. 2422 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2423 check_safepoint_and_suspend_for_native_trans(thread); 2424 2425 if (thread->has_async_exception()) { 2426 // We are in _thread_in_native_trans state, don't handle unsafe 2427 // access error since that may block. 2428 thread->check_and_handle_async_exceptions(false); 2429 } 2430 } 2431 2432 // This is a variant of the normal 2433 // check_special_condition_for_native_trans with slightly different 2434 // semantics for use by critical native wrappers. It does all the 2435 // normal checks but also performs the transition back into 2436 // thread_in_Java state. This is required so that critical natives 2437 // can potentially block and perform a GC if they are the last thread 2438 // exiting the GC_locker. 2439 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2440 check_special_condition_for_native_trans(thread); 2441 2442 // Finish the transition 2443 thread->set_thread_state(_thread_in_Java); 2444 2445 if (thread->do_critical_native_unlock()) { 2446 ThreadInVMfromJavaNoAsyncException tiv(thread); 2447 GC_locker::unlock_critical(thread); 2448 thread->clear_critical_native_unlock(); 2449 } 2450 } 2451 2452 // We need to guarantee the Threads_lock here, since resumes are not 2453 // allowed during safepoint synchronization 2454 // Can only resume from an external suspension 2455 void JavaThread::java_resume() { 2456 assert_locked_or_safepoint(Threads_lock); 2457 2458 // Sanity check: thread is gone, has started exiting or the thread 2459 // was not externally suspended. 2460 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2461 return; 2462 } 2463 2464 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2465 2466 clear_external_suspend(); 2467 2468 if (is_ext_suspended()) { 2469 clear_ext_suspended(); 2470 SR_lock()->notify_all(); 2471 } 2472 } 2473 2474 void JavaThread::create_stack_guard_pages() { 2475 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2476 address low_addr = stack_base() - stack_size(); 2477 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2478 2479 int allocate = os::allocate_stack_guard_pages(); 2480 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2481 2482 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2483 warning("Attempt to allocate stack guard pages failed."); 2484 return; 2485 } 2486 2487 if (os::guard_memory((char *) low_addr, len)) { 2488 _stack_guard_state = stack_guard_enabled; 2489 } else { 2490 warning("Attempt to protect stack guard pages failed."); 2491 if (os::uncommit_memory((char *) low_addr, len)) { 2492 warning("Attempt to deallocate stack guard pages failed."); 2493 } 2494 } 2495 } 2496 2497 void JavaThread::remove_stack_guard_pages() { 2498 assert(Thread::current() == this, "from different thread"); 2499 if (_stack_guard_state == stack_guard_unused) return; 2500 address low_addr = stack_base() - stack_size(); 2501 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2502 2503 if (os::allocate_stack_guard_pages()) { 2504 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2505 _stack_guard_state = stack_guard_unused; 2506 } else { 2507 warning("Attempt to deallocate stack guard pages failed."); 2508 } 2509 } else { 2510 if (_stack_guard_state == stack_guard_unused) return; 2511 if (os::unguard_memory((char *) low_addr, len)) { 2512 _stack_guard_state = stack_guard_unused; 2513 } else { 2514 warning("Attempt to unprotect stack guard pages failed."); 2515 } 2516 } 2517 } 2518 2519 void JavaThread::enable_stack_yellow_zone() { 2520 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2521 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2522 2523 // The base notation is from the stacks point of view, growing downward. 2524 // We need to adjust it to work correctly with guard_memory() 2525 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2526 2527 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2528 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2529 2530 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2531 _stack_guard_state = stack_guard_enabled; 2532 } else { 2533 warning("Attempt to guard stack yellow zone failed."); 2534 } 2535 enable_register_stack_guard(); 2536 } 2537 2538 void JavaThread::disable_stack_yellow_zone() { 2539 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2540 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2541 2542 // Simply return if called for a thread that does not use guard pages. 2543 if (_stack_guard_state == stack_guard_unused) return; 2544 2545 // The base notation is from the stacks point of view, growing downward. 2546 // We need to adjust it to work correctly with guard_memory() 2547 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2548 2549 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2550 _stack_guard_state = stack_guard_yellow_disabled; 2551 } else { 2552 warning("Attempt to unguard stack yellow zone failed."); 2553 } 2554 disable_register_stack_guard(); 2555 } 2556 2557 void JavaThread::enable_stack_red_zone() { 2558 // The base notation is from the stacks point of view, growing downward. 2559 // We need to adjust it to work correctly with guard_memory() 2560 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2561 address base = stack_red_zone_base() - stack_red_zone_size(); 2562 2563 guarantee(base < stack_base(),"Error calculating stack red zone"); 2564 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2565 2566 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2567 warning("Attempt to guard stack red zone failed."); 2568 } 2569 } 2570 2571 void JavaThread::disable_stack_red_zone() { 2572 // The base notation is from the stacks point of view, growing downward. 2573 // We need to adjust it to work correctly with guard_memory() 2574 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2575 address base = stack_red_zone_base() - stack_red_zone_size(); 2576 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2577 warning("Attempt to unguard stack red zone failed."); 2578 } 2579 } 2580 2581 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2582 // ignore is there is no stack 2583 if (!has_last_Java_frame()) return; 2584 // traverse the stack frames. Starts from top frame. 2585 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2586 frame* fr = fst.current(); 2587 f(fr, fst.register_map()); 2588 } 2589 } 2590 2591 2592 #ifndef PRODUCT 2593 // Deoptimization 2594 // Function for testing deoptimization 2595 void JavaThread::deoptimize() { 2596 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2597 StackFrameStream fst(this, UseBiasedLocking); 2598 bool deopt = false; // Dump stack only if a deopt actually happens. 2599 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2600 // Iterate over all frames in the thread and deoptimize 2601 for(; !fst.is_done(); fst.next()) { 2602 if(fst.current()->can_be_deoptimized()) { 2603 2604 if (only_at) { 2605 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2606 // consists of comma or carriage return separated numbers so 2607 // search for the current bci in that string. 2608 address pc = fst.current()->pc(); 2609 nmethod* nm = (nmethod*) fst.current()->cb(); 2610 ScopeDesc* sd = nm->scope_desc_at( pc); 2611 char buffer[8]; 2612 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2613 size_t len = strlen(buffer); 2614 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2615 while (found != NULL) { 2616 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2617 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2618 // Check that the bci found is bracketed by terminators. 2619 break; 2620 } 2621 found = strstr(found + 1, buffer); 2622 } 2623 if (!found) { 2624 continue; 2625 } 2626 } 2627 2628 if (DebugDeoptimization && !deopt) { 2629 deopt = true; // One-time only print before deopt 2630 tty->print_cr("[BEFORE Deoptimization]"); 2631 trace_frames(); 2632 trace_stack(); 2633 } 2634 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2635 } 2636 } 2637 2638 if (DebugDeoptimization && deopt) { 2639 tty->print_cr("[AFTER Deoptimization]"); 2640 trace_frames(); 2641 } 2642 } 2643 2644 2645 // Make zombies 2646 void JavaThread::make_zombies() { 2647 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2648 if (fst.current()->can_be_deoptimized()) { 2649 // it is a Java nmethod 2650 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2651 nm->make_not_entrant(); 2652 } 2653 } 2654 } 2655 #endif // PRODUCT 2656 2657 2658 void JavaThread::deoptimized_wrt_marked_nmethods() { 2659 if (!has_last_Java_frame()) return; 2660 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2661 StackFrameStream fst(this, UseBiasedLocking); 2662 for(; !fst.is_done(); fst.next()) { 2663 if (fst.current()->should_be_deoptimized()) { 2664 if (LogCompilation && xtty != NULL) { 2665 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2666 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2667 this->name(), nm != NULL ? nm->compile_id() : -1); 2668 } 2669 2670 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2671 } 2672 } 2673 } 2674 2675 2676 // GC support 2677 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2678 2679 void JavaThread::gc_epilogue() { 2680 frames_do(frame_gc_epilogue); 2681 } 2682 2683 2684 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2685 2686 void JavaThread::gc_prologue() { 2687 frames_do(frame_gc_prologue); 2688 } 2689 2690 // If the caller is a NamedThread, then remember, in the current scope, 2691 // the given JavaThread in its _processed_thread field. 2692 class RememberProcessedThread: public StackObj { 2693 NamedThread* _cur_thr; 2694 public: 2695 RememberProcessedThread(JavaThread* jthr) { 2696 Thread* thread = Thread::current(); 2697 if (thread->is_Named_thread()) { 2698 _cur_thr = (NamedThread *)thread; 2699 _cur_thr->set_processed_thread(jthr); 2700 } else { 2701 _cur_thr = NULL; 2702 } 2703 } 2704 2705 ~RememberProcessedThread() { 2706 if (_cur_thr) { 2707 _cur_thr->set_processed_thread(NULL); 2708 } 2709 } 2710 }; 2711 2712 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 2713 // Verify that the deferred card marks have been flushed. 2714 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2715 2716 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2717 // since there may be more than one thread using each ThreadProfiler. 2718 2719 // Traverse the GCHandles 2720 Thread::oops_do(f, cld_f, cf); 2721 2722 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2723 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2724 2725 if (has_last_Java_frame()) { 2726 // Record JavaThread to GC thread 2727 RememberProcessedThread rpt(this); 2728 2729 // Traverse the privileged stack 2730 if (_privileged_stack_top != NULL) { 2731 _privileged_stack_top->oops_do(f); 2732 } 2733 2734 // traverse the registered growable array 2735 if (_array_for_gc != NULL) { 2736 for (int index = 0; index < _array_for_gc->length(); index++) { 2737 f->do_oop(_array_for_gc->adr_at(index)); 2738 } 2739 } 2740 2741 // Traverse the monitor chunks 2742 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2743 chunk->oops_do(f); 2744 } 2745 2746 // Traverse the execution stack 2747 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2748 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2749 } 2750 } 2751 2752 // callee_target is never live across a gc point so NULL it here should 2753 // it still contain a methdOop. 2754 2755 set_callee_target(NULL); 2756 2757 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2758 // If we have deferred set_locals there might be oops waiting to be 2759 // written 2760 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2761 if (list != NULL) { 2762 for (int i = 0; i < list->length(); i++) { 2763 list->at(i)->oops_do(f); 2764 } 2765 } 2766 2767 // Traverse instance variables at the end since the GC may be moving things 2768 // around using this function 2769 f->do_oop((oop*) &_threadObj); 2770 f->do_oop((oop*) &_vm_result); 2771 f->do_oop((oop*) &_exception_oop); 2772 f->do_oop((oop*) &_pending_async_exception); 2773 2774 if (jvmti_thread_state() != NULL) { 2775 jvmti_thread_state()->oops_do(f); 2776 } 2777 } 2778 2779 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2780 Thread::nmethods_do(cf); // (super method is a no-op) 2781 2782 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2783 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2784 2785 if (has_last_Java_frame()) { 2786 // Traverse the execution stack 2787 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2788 fst.current()->nmethods_do(cf); 2789 } 2790 } 2791 } 2792 2793 void JavaThread::metadata_do(void f(Metadata*)) { 2794 Thread::metadata_do(f); 2795 if (has_last_Java_frame()) { 2796 // Traverse the execution stack to call f() on the methods in the stack 2797 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2798 fst.current()->metadata_do(f); 2799 } 2800 } else if (is_Compiler_thread()) { 2801 // need to walk ciMetadata in current compile tasks to keep alive. 2802 CompilerThread* ct = (CompilerThread*)this; 2803 if (ct->env() != NULL) { 2804 ct->env()->metadata_do(f); 2805 } 2806 } 2807 } 2808 2809 // Printing 2810 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2811 switch (_thread_state) { 2812 case _thread_uninitialized: return "_thread_uninitialized"; 2813 case _thread_new: return "_thread_new"; 2814 case _thread_new_trans: return "_thread_new_trans"; 2815 case _thread_in_native: return "_thread_in_native"; 2816 case _thread_in_native_trans: return "_thread_in_native_trans"; 2817 case _thread_in_vm: return "_thread_in_vm"; 2818 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2819 case _thread_in_Java: return "_thread_in_Java"; 2820 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2821 case _thread_blocked: return "_thread_blocked"; 2822 case _thread_blocked_trans: return "_thread_blocked_trans"; 2823 default: return "unknown thread state"; 2824 } 2825 } 2826 2827 #ifndef PRODUCT 2828 void JavaThread::print_thread_state_on(outputStream *st) const { 2829 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2830 }; 2831 void JavaThread::print_thread_state() const { 2832 print_thread_state_on(tty); 2833 }; 2834 #endif // PRODUCT 2835 2836 // Called by Threads::print() for VM_PrintThreads operation 2837 void JavaThread::print_on(outputStream *st) const { 2838 st->print("\"%s\" ", get_thread_name()); 2839 oop thread_oop = threadObj(); 2840 if (thread_oop != NULL) { 2841 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2842 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2843 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2844 } 2845 Thread::print_on(st); 2846 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2847 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2848 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2849 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2850 } 2851 #ifndef PRODUCT 2852 print_thread_state_on(st); 2853 _safepoint_state->print_on(st); 2854 #endif // PRODUCT 2855 } 2856 2857 // Called by fatal error handler. The difference between this and 2858 // JavaThread::print() is that we can't grab lock or allocate memory. 2859 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2860 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2861 oop thread_obj = threadObj(); 2862 if (thread_obj != NULL) { 2863 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2864 } 2865 st->print(" ["); 2866 st->print("%s", _get_thread_state_name(_thread_state)); 2867 if (osthread()) { 2868 st->print(", id=%d", osthread()->thread_id()); 2869 } 2870 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2871 _stack_base - _stack_size, _stack_base); 2872 st->print("]"); 2873 return; 2874 } 2875 2876 // Verification 2877 2878 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2879 2880 void JavaThread::verify() { 2881 // Verify oops in the thread. 2882 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2883 2884 // Verify the stack frames. 2885 frames_do(frame_verify); 2886 } 2887 2888 // CR 6300358 (sub-CR 2137150) 2889 // Most callers of this method assume that it can't return NULL but a 2890 // thread may not have a name whilst it is in the process of attaching to 2891 // the VM - see CR 6412693, and there are places where a JavaThread can be 2892 // seen prior to having it's threadObj set (eg JNI attaching threads and 2893 // if vm exit occurs during initialization). These cases can all be accounted 2894 // for such that this method never returns NULL. 2895 const char* JavaThread::get_thread_name() const { 2896 #ifdef ASSERT 2897 // early safepoints can hit while current thread does not yet have TLS 2898 if (!SafepointSynchronize::is_at_safepoint()) { 2899 Thread *cur = Thread::current(); 2900 if (!(cur->is_Java_thread() && cur == this)) { 2901 // Current JavaThreads are allowed to get their own name without 2902 // the Threads_lock. 2903 assert_locked_or_safepoint(Threads_lock); 2904 } 2905 } 2906 #endif // ASSERT 2907 return get_thread_name_string(); 2908 } 2909 2910 // Returns a non-NULL representation of this thread's name, or a suitable 2911 // descriptive string if there is no set name 2912 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2913 const char* name_str; 2914 oop thread_obj = threadObj(); 2915 if (thread_obj != NULL) { 2916 typeArrayOop name = java_lang_Thread::name(thread_obj); 2917 if (name != NULL) { 2918 if (buf == NULL) { 2919 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2920 } 2921 else { 2922 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2923 } 2924 } 2925 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2926 name_str = "<no-name - thread is attaching>"; 2927 } 2928 else { 2929 name_str = Thread::name(); 2930 } 2931 } 2932 else { 2933 name_str = Thread::name(); 2934 } 2935 assert(name_str != NULL, "unexpected NULL thread name"); 2936 return name_str; 2937 } 2938 2939 2940 const char* JavaThread::get_threadgroup_name() const { 2941 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2942 oop thread_obj = threadObj(); 2943 if (thread_obj != NULL) { 2944 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2945 if (thread_group != NULL) { 2946 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2947 // ThreadGroup.name can be null 2948 if (name != NULL) { 2949 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2950 return str; 2951 } 2952 } 2953 } 2954 return NULL; 2955 } 2956 2957 const char* JavaThread::get_parent_name() const { 2958 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2959 oop thread_obj = threadObj(); 2960 if (thread_obj != NULL) { 2961 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2962 if (thread_group != NULL) { 2963 oop parent = java_lang_ThreadGroup::parent(thread_group); 2964 if (parent != NULL) { 2965 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2966 // ThreadGroup.name can be null 2967 if (name != NULL) { 2968 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2969 return str; 2970 } 2971 } 2972 } 2973 } 2974 return NULL; 2975 } 2976 2977 ThreadPriority JavaThread::java_priority() const { 2978 oop thr_oop = threadObj(); 2979 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2980 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2981 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2982 return priority; 2983 } 2984 2985 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2986 2987 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2988 // Link Java Thread object <-> C++ Thread 2989 2990 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2991 // and put it into a new Handle. The Handle "thread_oop" can then 2992 // be used to pass the C++ thread object to other methods. 2993 2994 // Set the Java level thread object (jthread) field of the 2995 // new thread (a JavaThread *) to C++ thread object using the 2996 // "thread_oop" handle. 2997 2998 // Set the thread field (a JavaThread *) of the 2999 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3000 3001 Handle thread_oop(Thread::current(), 3002 JNIHandles::resolve_non_null(jni_thread)); 3003 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3004 "must be initialized"); 3005 set_threadObj(thread_oop()); 3006 java_lang_Thread::set_thread(thread_oop(), this); 3007 3008 if (prio == NoPriority) { 3009 prio = java_lang_Thread::priority(thread_oop()); 3010 assert(prio != NoPriority, "A valid priority should be present"); 3011 } 3012 3013 // Push the Java priority down to the native thread; needs Threads_lock 3014 Thread::set_priority(this, prio); 3015 3016 // Add the new thread to the Threads list and set it in motion. 3017 // We must have threads lock in order to call Threads::add. 3018 // It is crucial that we do not block before the thread is 3019 // added to the Threads list for if a GC happens, then the java_thread oop 3020 // will not be visited by GC. 3021 Threads::add(this); 3022 } 3023 3024 oop JavaThread::current_park_blocker() { 3025 // Support for JSR-166 locks 3026 oop thread_oop = threadObj(); 3027 if (thread_oop != NULL && 3028 JDK_Version::current().supports_thread_park_blocker()) { 3029 return java_lang_Thread::park_blocker(thread_oop); 3030 } 3031 return NULL; 3032 } 3033 3034 3035 void JavaThread::print_stack_on(outputStream* st) { 3036 if (!has_last_Java_frame()) return; 3037 ResourceMark rm; 3038 HandleMark hm; 3039 3040 RegisterMap reg_map(this); 3041 vframe* start_vf = last_java_vframe(®_map); 3042 int count = 0; 3043 for (vframe* f = start_vf; f; f = f->sender() ) { 3044 if (f->is_java_frame()) { 3045 javaVFrame* jvf = javaVFrame::cast(f); 3046 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3047 3048 // Print out lock information 3049 if (JavaMonitorsInStackTrace) { 3050 jvf->print_lock_info_on(st, count); 3051 } 3052 } else { 3053 // Ignore non-Java frames 3054 } 3055 3056 // Bail-out case for too deep stacks 3057 count++; 3058 if (MaxJavaStackTraceDepth == count) return; 3059 } 3060 } 3061 3062 3063 // JVMTI PopFrame support 3064 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3065 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3066 if (in_bytes(size_in_bytes) != 0) { 3067 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3068 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3069 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3070 } 3071 } 3072 3073 void* JavaThread::popframe_preserved_args() { 3074 return _popframe_preserved_args; 3075 } 3076 3077 ByteSize JavaThread::popframe_preserved_args_size() { 3078 return in_ByteSize(_popframe_preserved_args_size); 3079 } 3080 3081 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3082 int sz = in_bytes(popframe_preserved_args_size()); 3083 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3084 return in_WordSize(sz / wordSize); 3085 } 3086 3087 void JavaThread::popframe_free_preserved_args() { 3088 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3089 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3090 _popframe_preserved_args = NULL; 3091 _popframe_preserved_args_size = 0; 3092 } 3093 3094 #ifndef PRODUCT 3095 3096 void JavaThread::trace_frames() { 3097 tty->print_cr("[Describe stack]"); 3098 int frame_no = 1; 3099 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3100 tty->print(" %d. ", frame_no++); 3101 fst.current()->print_value_on(tty,this); 3102 tty->cr(); 3103 } 3104 } 3105 3106 class PrintAndVerifyOopClosure: public OopClosure { 3107 protected: 3108 template <class T> inline void do_oop_work(T* p) { 3109 oop obj = oopDesc::load_decode_heap_oop(p); 3110 if (obj == NULL) return; 3111 tty->print(INTPTR_FORMAT ": ", p); 3112 if (obj->is_oop_or_null()) { 3113 if (obj->is_objArray()) { 3114 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3115 } else { 3116 obj->print(); 3117 } 3118 } else { 3119 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3120 } 3121 tty->cr(); 3122 } 3123 public: 3124 virtual void do_oop(oop* p) { do_oop_work(p); } 3125 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3126 }; 3127 3128 3129 static void oops_print(frame* f, const RegisterMap *map) { 3130 PrintAndVerifyOopClosure print; 3131 f->print_value(); 3132 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3133 } 3134 3135 // Print our all the locations that contain oops and whether they are 3136 // valid or not. This useful when trying to find the oldest frame 3137 // where an oop has gone bad since the frame walk is from youngest to 3138 // oldest. 3139 void JavaThread::trace_oops() { 3140 tty->print_cr("[Trace oops]"); 3141 frames_do(oops_print); 3142 } 3143 3144 3145 #ifdef ASSERT 3146 // Print or validate the layout of stack frames 3147 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3148 ResourceMark rm; 3149 PRESERVE_EXCEPTION_MARK; 3150 FrameValues values; 3151 int frame_no = 0; 3152 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3153 fst.current()->describe(values, ++frame_no); 3154 if (depth == frame_no) break; 3155 } 3156 if (validate_only) { 3157 values.validate(); 3158 } else { 3159 tty->print_cr("[Describe stack layout]"); 3160 values.print(this); 3161 } 3162 } 3163 #endif 3164 3165 void JavaThread::trace_stack_from(vframe* start_vf) { 3166 ResourceMark rm; 3167 int vframe_no = 1; 3168 for (vframe* f = start_vf; f; f = f->sender() ) { 3169 if (f->is_java_frame()) { 3170 javaVFrame::cast(f)->print_activation(vframe_no++); 3171 } else { 3172 f->print(); 3173 } 3174 if (vframe_no > StackPrintLimit) { 3175 tty->print_cr("...<more frames>..."); 3176 return; 3177 } 3178 } 3179 } 3180 3181 3182 void JavaThread::trace_stack() { 3183 if (!has_last_Java_frame()) return; 3184 ResourceMark rm; 3185 HandleMark hm; 3186 RegisterMap reg_map(this); 3187 trace_stack_from(last_java_vframe(®_map)); 3188 } 3189 3190 3191 #endif // PRODUCT 3192 3193 3194 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3195 assert(reg_map != NULL, "a map must be given"); 3196 frame f = last_frame(); 3197 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3198 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3199 } 3200 return NULL; 3201 } 3202 3203 3204 Klass* JavaThread::security_get_caller_class(int depth) { 3205 vframeStream vfst(this); 3206 vfst.security_get_caller_frame(depth); 3207 if (!vfst.at_end()) { 3208 return vfst.method()->method_holder(); 3209 } 3210 return NULL; 3211 } 3212 3213 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3214 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3215 CompileBroker::compiler_thread_loop(); 3216 } 3217 3218 // Create a CompilerThread 3219 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3220 : JavaThread(&compiler_thread_entry) { 3221 _env = NULL; 3222 _log = NULL; 3223 _task = NULL; 3224 _queue = queue; 3225 _counters = counters; 3226 _buffer_blob = NULL; 3227 _scanned_nmethod = NULL; 3228 3229 #ifndef PRODUCT 3230 _ideal_graph_printer = NULL; 3231 #endif 3232 } 3233 3234 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 3235 JavaThread::oops_do(f, cld_f, cf); 3236 if (_scanned_nmethod != NULL && cf != NULL) { 3237 // Safepoints can occur when the sweeper is scanning an nmethod so 3238 // process it here to make sure it isn't unloaded in the middle of 3239 // a scan. 3240 cf->do_code_blob(_scanned_nmethod); 3241 } 3242 } 3243 3244 // ======= Threads ======== 3245 3246 // The Threads class links together all active threads, and provides 3247 // operations over all threads. It is protected by its own Mutex 3248 // lock, which is also used in other contexts to protect thread 3249 // operations from having the thread being operated on from exiting 3250 // and going away unexpectedly (e.g., safepoint synchronization) 3251 3252 JavaThread* Threads::_thread_list = NULL; 3253 int Threads::_number_of_threads = 0; 3254 int Threads::_number_of_non_daemon_threads = 0; 3255 int Threads::_return_code = 0; 3256 size_t JavaThread::_stack_size_at_create = 0; 3257 #ifdef ASSERT 3258 bool Threads::_vm_complete = false; 3259 #endif 3260 3261 // All JavaThreads 3262 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3263 3264 void os_stream(); 3265 3266 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3267 void Threads::threads_do(ThreadClosure* tc) { 3268 assert_locked_or_safepoint(Threads_lock); 3269 // ALL_JAVA_THREADS iterates through all JavaThreads 3270 ALL_JAVA_THREADS(p) { 3271 tc->do_thread(p); 3272 } 3273 // Someday we could have a table or list of all non-JavaThreads. 3274 // For now, just manually iterate through them. 3275 tc->do_thread(VMThread::vm_thread()); 3276 Universe::heap()->gc_threads_do(tc); 3277 WatcherThread *wt = WatcherThread::watcher_thread(); 3278 // Strictly speaking, the following NULL check isn't sufficient to make sure 3279 // the data for WatcherThread is still valid upon being examined. However, 3280 // considering that WatchThread terminates when the VM is on the way to 3281 // exit at safepoint, the chance of the above is extremely small. The right 3282 // way to prevent termination of WatcherThread would be to acquire 3283 // Terminator_lock, but we can't do that without violating the lock rank 3284 // checking in some cases. 3285 if (wt != NULL) 3286 tc->do_thread(wt); 3287 3288 // If CompilerThreads ever become non-JavaThreads, add them here 3289 } 3290 3291 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3292 3293 extern void JDK_Version_init(); 3294 3295 // Check version 3296 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3297 3298 // Initialize the output stream module 3299 ostream_init(); 3300 3301 // Process java launcher properties. 3302 Arguments::process_sun_java_launcher_properties(args); 3303 3304 // Initialize the os module before using TLS 3305 os::init(); 3306 3307 // Initialize system properties. 3308 Arguments::init_system_properties(); 3309 3310 // So that JDK version can be used as a discrimintor when parsing arguments 3311 JDK_Version_init(); 3312 3313 // Update/Initialize System properties after JDK version number is known 3314 Arguments::init_version_specific_system_properties(); 3315 3316 // Parse arguments 3317 jint parse_result = Arguments::parse(args); 3318 if (parse_result != JNI_OK) return parse_result; 3319 3320 if (PauseAtStartup) { 3321 os::pause(); 3322 } 3323 3324 #ifndef USDT2 3325 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3326 #else /* USDT2 */ 3327 HOTSPOT_VM_INIT_BEGIN(); 3328 #endif /* USDT2 */ 3329 3330 // Record VM creation timing statistics 3331 TraceVmCreationTime create_vm_timer; 3332 create_vm_timer.start(); 3333 3334 // Timing (must come after argument parsing) 3335 TraceTime timer("Create VM", TraceStartupTime); 3336 3337 // Initialize the os module after parsing the args 3338 jint os_init_2_result = os::init_2(); 3339 if (os_init_2_result != JNI_OK) return os_init_2_result; 3340 3341 jint adjust_after_os_result = Arguments::adjust_after_os(); 3342 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3343 3344 // intialize TLS 3345 ThreadLocalStorage::init(); 3346 3347 // Bootstrap native memory tracking, so it can start recording memory 3348 // activities before worker thread is started. This is the first phase 3349 // of bootstrapping, VM is currently running in single-thread mode. 3350 MemTracker::bootstrap_single_thread(); 3351 3352 // Initialize output stream logging 3353 ostream_init_log(); 3354 3355 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3356 // Must be before create_vm_init_agents() 3357 if (Arguments::init_libraries_at_startup()) { 3358 convert_vm_init_libraries_to_agents(); 3359 } 3360 3361 // Launch -agentlib/-agentpath and converted -Xrun agents 3362 if (Arguments::init_agents_at_startup()) { 3363 create_vm_init_agents(); 3364 } 3365 3366 // Initialize Threads state 3367 _thread_list = NULL; 3368 _number_of_threads = 0; 3369 _number_of_non_daemon_threads = 0; 3370 3371 // Initialize global data structures and create system classes in heap 3372 vm_init_globals(); 3373 3374 // Attach the main thread to this os thread 3375 JavaThread* main_thread = new JavaThread(); 3376 main_thread->set_thread_state(_thread_in_vm); 3377 // must do this before set_active_handles and initialize_thread_local_storage 3378 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3379 // change the stack size recorded here to one based on the java thread 3380 // stacksize. This adjusted size is what is used to figure the placement 3381 // of the guard pages. 3382 main_thread->record_stack_base_and_size(); 3383 main_thread->initialize_thread_local_storage(); 3384 3385 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3386 3387 if (!main_thread->set_as_starting_thread()) { 3388 vm_shutdown_during_initialization( 3389 "Failed necessary internal allocation. Out of swap space"); 3390 delete main_thread; 3391 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3392 return JNI_ENOMEM; 3393 } 3394 3395 // Enable guard page *after* os::create_main_thread(), otherwise it would 3396 // crash Linux VM, see notes in os_linux.cpp. 3397 main_thread->create_stack_guard_pages(); 3398 3399 // Initialize Java-Level synchronization subsystem 3400 ObjectMonitor::Initialize() ; 3401 3402 // Second phase of bootstrapping, VM is about entering multi-thread mode 3403 MemTracker::bootstrap_multi_thread(); 3404 3405 // Initialize global modules 3406 jint status = init_globals(); 3407 if (status != JNI_OK) { 3408 delete main_thread; 3409 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3410 return status; 3411 } 3412 3413 // Should be done after the heap is fully created 3414 main_thread->cache_global_variables(); 3415 3416 HandleMark hm; 3417 3418 { MutexLocker mu(Threads_lock); 3419 Threads::add(main_thread); 3420 } 3421 3422 // Any JVMTI raw monitors entered in onload will transition into 3423 // real raw monitor. VM is setup enough here for raw monitor enter. 3424 JvmtiExport::transition_pending_onload_raw_monitors(); 3425 3426 // Fully start NMT 3427 MemTracker::start(); 3428 3429 // Create the VMThread 3430 { TraceTime timer("Start VMThread", TraceStartupTime); 3431 VMThread::create(); 3432 Thread* vmthread = VMThread::vm_thread(); 3433 3434 if (!os::create_thread(vmthread, os::vm_thread)) 3435 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3436 3437 // Wait for the VM thread to become ready, and VMThread::run to initialize 3438 // Monitors can have spurious returns, must always check another state flag 3439 { 3440 MutexLocker ml(Notify_lock); 3441 os::start_thread(vmthread); 3442 while (vmthread->active_handles() == NULL) { 3443 Notify_lock->wait(); 3444 } 3445 } 3446 } 3447 3448 assert (Universe::is_fully_initialized(), "not initialized"); 3449 if (VerifyDuringStartup) { 3450 // Make sure we're starting with a clean slate. 3451 VM_Verify verify_op; 3452 VMThread::execute(&verify_op); 3453 } 3454 3455 EXCEPTION_MARK; 3456 3457 // At this point, the Universe is initialized, but we have not executed 3458 // any byte code. Now is a good time (the only time) to dump out the 3459 // internal state of the JVM for sharing. 3460 if (DumpSharedSpaces) { 3461 MetaspaceShared::preload_and_dump(CHECK_0); 3462 ShouldNotReachHere(); 3463 } 3464 3465 // Always call even when there are not JVMTI environments yet, since environments 3466 // may be attached late and JVMTI must track phases of VM execution 3467 JvmtiExport::enter_start_phase(); 3468 3469 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3470 JvmtiExport::post_vm_start(); 3471 3472 { 3473 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3474 3475 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3476 create_vm_init_libraries(); 3477 } 3478 3479 initialize_class(vmSymbols::java_lang_String(), CHECK_0); 3480 3481 if (AggressiveOpts) { 3482 { 3483 // Forcibly initialize java/util/HashMap and mutate the private 3484 // static final "frontCacheEnabled" field before we start creating instances 3485 #ifdef ASSERT 3486 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3487 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 3488 #endif 3489 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3490 KlassHandle k = KlassHandle(THREAD, k_o); 3491 guarantee(k.not_null(), "Must find java/util/HashMap"); 3492 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3493 ik->initialize(CHECK_0); 3494 fieldDescriptor fd; 3495 // Possible we might not find this field; if so, don't break 3496 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3497 k()->java_mirror()->bool_field_put(fd.offset(), true); 3498 } 3499 } 3500 3501 if (UseStringCache) { 3502 // Forcibly initialize java/lang/StringValue and mutate the private 3503 // static final "stringCacheEnabled" field before we start creating instances 3504 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0); 3505 // Possible that StringValue isn't present: if so, silently don't break 3506 if (k_o != NULL) { 3507 KlassHandle k = KlassHandle(THREAD, k_o); 3508 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3509 ik->initialize(CHECK_0); 3510 fieldDescriptor fd; 3511 // Possible we might not find this field: if so, silently don't break 3512 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3513 k()->java_mirror()->bool_field_put(fd.offset(), true); 3514 } 3515 } 3516 } 3517 } 3518 3519 // Initialize java_lang.System (needed before creating the thread) 3520 initialize_class(vmSymbols::java_lang_System(), CHECK_0); 3521 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0); 3522 Handle thread_group = create_initial_thread_group(CHECK_0); 3523 Universe::set_main_thread_group(thread_group()); 3524 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0); 3525 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 3526 main_thread->set_threadObj(thread_object); 3527 // Set thread status to running since main thread has 3528 // been started and running. 3529 java_lang_Thread::set_thread_status(thread_object, 3530 java_lang_Thread::RUNNABLE); 3531 3532 // The VM creates & returns objects of this class. Make sure it's initialized. 3533 initialize_class(vmSymbols::java_lang_Class(), CHECK_0); 3534 3535 // The VM preresolves methods to these classes. Make sure that they get initialized 3536 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0); 3537 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0); 3538 call_initializeSystemClass(CHECK_0); 3539 3540 // get the Java runtime name after java.lang.System is initialized 3541 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3542 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3543 3544 // an instance of OutOfMemory exception has been allocated earlier 3545 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0); 3546 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0); 3547 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0); 3548 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0); 3549 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0); 3550 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0); 3551 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0); 3552 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0); 3553 } 3554 3555 // See : bugid 4211085. 3556 // Background : the static initializer of java.lang.Compiler tries to read 3557 // property"java.compiler" and read & write property "java.vm.info". 3558 // When a security manager is installed through the command line 3559 // option "-Djava.security.manager", the above properties are not 3560 // readable and the static initializer for java.lang.Compiler fails 3561 // resulting in a NoClassDefFoundError. This can happen in any 3562 // user code which calls methods in java.lang.Compiler. 3563 // Hack : the hack is to pre-load and initialize this class, so that only 3564 // system domains are on the stack when the properties are read. 3565 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3566 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3567 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3568 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3569 // Once that is done, we should remove this hack. 3570 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0); 3571 3572 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3573 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3574 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3575 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3576 // This should also be taken out as soon as 4211383 gets fixed. 3577 reset_vm_info_property(CHECK_0); 3578 3579 quicken_jni_functions(); 3580 3581 // Must be run after init_ft which initializes ft_enabled 3582 if (TRACE_INITIALIZE() != JNI_OK) { 3583 vm_exit_during_initialization("Failed to initialize tracing backend"); 3584 } 3585 3586 // Set flag that basic initialization has completed. Used by exceptions and various 3587 // debug stuff, that does not work until all basic classes have been initialized. 3588 set_init_completed(); 3589 3590 #ifndef USDT2 3591 HS_DTRACE_PROBE(hotspot, vm__init__end); 3592 #else /* USDT2 */ 3593 HOTSPOT_VM_INIT_END(); 3594 #endif /* USDT2 */ 3595 3596 // record VM initialization completion time 3597 #if INCLUDE_MANAGEMENT 3598 Management::record_vm_init_completed(); 3599 #endif // INCLUDE_MANAGEMENT 3600 3601 // Compute system loader. Note that this has to occur after set_init_completed, since 3602 // valid exceptions may be thrown in the process. 3603 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3604 // set_init_completed has just been called, causing exceptions not to be shortcut 3605 // anymore. We call vm_exit_during_initialization directly instead. 3606 SystemDictionary::compute_java_system_loader(THREAD); 3607 if (HAS_PENDING_EXCEPTION) { 3608 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3609 } 3610 3611 #if INCLUDE_ALL_GCS 3612 // Support for ConcurrentMarkSweep. This should be cleaned up 3613 // and better encapsulated. The ugly nested if test would go away 3614 // once things are properly refactored. XXX YSR 3615 if (UseConcMarkSweepGC || UseG1GC) { 3616 if (UseConcMarkSweepGC) { 3617 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3618 } else { 3619 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3620 } 3621 if (HAS_PENDING_EXCEPTION) { 3622 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3623 } 3624 } 3625 #endif // INCLUDE_ALL_GCS 3626 3627 // Always call even when there are not JVMTI environments yet, since environments 3628 // may be attached late and JVMTI must track phases of VM execution 3629 JvmtiExport::enter_live_phase(); 3630 3631 // Signal Dispatcher needs to be started before VMInit event is posted 3632 os::signal_init(); 3633 3634 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3635 if (!DisableAttachMechanism) { 3636 if (StartAttachListener || AttachListener::init_at_startup()) { 3637 AttachListener::init(); 3638 } 3639 } 3640 3641 // Launch -Xrun agents 3642 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3643 // back-end can launch with -Xdebug -Xrunjdwp. 3644 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3645 create_vm_init_libraries(); 3646 } 3647 3648 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3649 JvmtiExport::post_vm_initialized(); 3650 3651 if (!TRACE_START()) { 3652 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3653 } 3654 3655 if (CleanChunkPoolAsync) { 3656 Chunk::start_chunk_pool_cleaner_task(); 3657 } 3658 3659 // initialize compiler(s) 3660 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3661 CompileBroker::compilation_init(); 3662 #endif 3663 3664 #if INCLUDE_MANAGEMENT 3665 Management::initialize(THREAD); 3666 #endif // INCLUDE_MANAGEMENT 3667 3668 if (HAS_PENDING_EXCEPTION) { 3669 // management agent fails to start possibly due to 3670 // configuration problem and is responsible for printing 3671 // stack trace if appropriate. Simply exit VM. 3672 vm_exit(1); 3673 } 3674 3675 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3676 if (Arguments::has_alloc_profile()) AllocationProfiler::engage(); 3677 if (MemProfiling) MemProfiler::engage(); 3678 StatSampler::engage(); 3679 if (CheckJNICalls) JniPeriodicChecker::engage(); 3680 3681 BiasedLocking::init(); 3682 3683 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3684 call_postVMInitHook(THREAD); 3685 // The Java side of PostVMInitHook.run must deal with all 3686 // exceptions and provide means of diagnosis. 3687 if (HAS_PENDING_EXCEPTION) { 3688 CLEAR_PENDING_EXCEPTION; 3689 } 3690 } 3691 3692 { 3693 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3694 // Make sure the watcher thread can be started by WatcherThread::start() 3695 // or by dynamic enrollment. 3696 WatcherThread::make_startable(); 3697 // Start up the WatcherThread if there are any periodic tasks 3698 // NOTE: All PeriodicTasks should be registered by now. If they 3699 // aren't, late joiners might appear to start slowly (we might 3700 // take a while to process their first tick). 3701 if (PeriodicTask::num_tasks() > 0) { 3702 WatcherThread::start(); 3703 } 3704 } 3705 3706 // Give os specific code one last chance to start 3707 os::init_3(); 3708 3709 create_vm_timer.end(); 3710 #ifdef ASSERT 3711 _vm_complete = true; 3712 #endif 3713 return JNI_OK; 3714 } 3715 3716 // type for the Agent_OnLoad and JVM_OnLoad entry points 3717 extern "C" { 3718 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3719 } 3720 // Find a command line agent library and return its entry point for 3721 // -agentlib: -agentpath: -Xrun 3722 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3723 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3724 OnLoadEntry_t on_load_entry = NULL; 3725 void *library = agent->os_lib(); // check if we have looked it up before 3726 3727 if (library == NULL) { 3728 char buffer[JVM_MAXPATHLEN]; 3729 char ebuf[1024]; 3730 const char *name = agent->name(); 3731 const char *msg = "Could not find agent library "; 3732 3733 if (agent->is_absolute_path()) { 3734 library = os::dll_load(name, ebuf, sizeof ebuf); 3735 if (library == NULL) { 3736 const char *sub_msg = " in absolute path, with error: "; 3737 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3738 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3739 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3740 // If we can't find the agent, exit. 3741 vm_exit_during_initialization(buf, NULL); 3742 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3743 } 3744 } else { 3745 // Try to load the agent from the standard dll directory 3746 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3747 name)) { 3748 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3749 } 3750 if (library == NULL) { // Try the local directory 3751 char ns[1] = {0}; 3752 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3753 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3754 } 3755 if (library == NULL) { 3756 const char *sub_msg = " on the library path, with error: "; 3757 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3758 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3759 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3760 // If we can't find the agent, exit. 3761 vm_exit_during_initialization(buf, NULL); 3762 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3763 } 3764 } 3765 } 3766 agent->set_os_lib(library); 3767 } 3768 3769 // Find the OnLoad function. 3770 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3771 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index])); 3772 if (on_load_entry != NULL) break; 3773 } 3774 return on_load_entry; 3775 } 3776 3777 // Find the JVM_OnLoad entry point 3778 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3779 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3780 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3781 } 3782 3783 // Find the Agent_OnLoad entry point 3784 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3785 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3786 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3787 } 3788 3789 // For backwards compatibility with -Xrun 3790 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3791 // treated like -agentpath: 3792 // Must be called before agent libraries are created 3793 void Threads::convert_vm_init_libraries_to_agents() { 3794 AgentLibrary* agent; 3795 AgentLibrary* next; 3796 3797 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3798 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3799 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3800 3801 // If there is an JVM_OnLoad function it will get called later, 3802 // otherwise see if there is an Agent_OnLoad 3803 if (on_load_entry == NULL) { 3804 on_load_entry = lookup_agent_on_load(agent); 3805 if (on_load_entry != NULL) { 3806 // switch it to the agent list -- so that Agent_OnLoad will be called, 3807 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3808 Arguments::convert_library_to_agent(agent); 3809 } else { 3810 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3811 } 3812 } 3813 } 3814 } 3815 3816 // Create agents for -agentlib: -agentpath: and converted -Xrun 3817 // Invokes Agent_OnLoad 3818 // Called very early -- before JavaThreads exist 3819 void Threads::create_vm_init_agents() { 3820 extern struct JavaVM_ main_vm; 3821 AgentLibrary* agent; 3822 3823 JvmtiExport::enter_onload_phase(); 3824 3825 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3826 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3827 3828 if (on_load_entry != NULL) { 3829 // Invoke the Agent_OnLoad function 3830 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3831 if (err != JNI_OK) { 3832 vm_exit_during_initialization("agent library failed to init", agent->name()); 3833 } 3834 } else { 3835 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3836 } 3837 } 3838 JvmtiExport::enter_primordial_phase(); 3839 } 3840 3841 extern "C" { 3842 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3843 } 3844 3845 void Threads::shutdown_vm_agents() { 3846 // Send any Agent_OnUnload notifications 3847 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3848 extern struct JavaVM_ main_vm; 3849 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3850 3851 // Find the Agent_OnUnload function. 3852 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3853 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3854 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3855 3856 // Invoke the Agent_OnUnload function 3857 if (unload_entry != NULL) { 3858 JavaThread* thread = JavaThread::current(); 3859 ThreadToNativeFromVM ttn(thread); 3860 HandleMark hm(thread); 3861 (*unload_entry)(&main_vm); 3862 break; 3863 } 3864 } 3865 } 3866 } 3867 3868 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3869 // Invokes JVM_OnLoad 3870 void Threads::create_vm_init_libraries() { 3871 extern struct JavaVM_ main_vm; 3872 AgentLibrary* agent; 3873 3874 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3875 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3876 3877 if (on_load_entry != NULL) { 3878 // Invoke the JVM_OnLoad function 3879 JavaThread* thread = JavaThread::current(); 3880 ThreadToNativeFromVM ttn(thread); 3881 HandleMark hm(thread); 3882 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3883 if (err != JNI_OK) { 3884 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3885 } 3886 } else { 3887 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3888 } 3889 } 3890 } 3891 3892 // Last thread running calls java.lang.Shutdown.shutdown() 3893 void JavaThread::invoke_shutdown_hooks() { 3894 HandleMark hm(this); 3895 3896 // We could get here with a pending exception, if so clear it now. 3897 if (this->has_pending_exception()) { 3898 this->clear_pending_exception(); 3899 } 3900 3901 EXCEPTION_MARK; 3902 Klass* k = 3903 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3904 THREAD); 3905 if (k != NULL) { 3906 // SystemDictionary::resolve_or_null will return null if there was 3907 // an exception. If we cannot load the Shutdown class, just don't 3908 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3909 // and finalizers (if runFinalizersOnExit is set) won't be run. 3910 // Note that if a shutdown hook was registered or runFinalizersOnExit 3911 // was called, the Shutdown class would have already been loaded 3912 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3913 instanceKlassHandle shutdown_klass (THREAD, k); 3914 JavaValue result(T_VOID); 3915 JavaCalls::call_static(&result, 3916 shutdown_klass, 3917 vmSymbols::shutdown_method_name(), 3918 vmSymbols::void_method_signature(), 3919 THREAD); 3920 } 3921 CLEAR_PENDING_EXCEPTION; 3922 } 3923 3924 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3925 // the program falls off the end of main(). Another VM exit path is through 3926 // vm_exit() when the program calls System.exit() to return a value or when 3927 // there is a serious error in VM. The two shutdown paths are not exactly 3928 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3929 // and VM_Exit op at VM level. 3930 // 3931 // Shutdown sequence: 3932 // + Shutdown native memory tracking if it is on 3933 // + Wait until we are the last non-daemon thread to execute 3934 // <-- every thing is still working at this moment --> 3935 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3936 // shutdown hooks, run finalizers if finalization-on-exit 3937 // + Call before_exit(), prepare for VM exit 3938 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3939 // currently the only user of this mechanism is File.deleteOnExit()) 3940 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3941 // post thread end and vm death events to JVMTI, 3942 // stop signal thread 3943 // + Call JavaThread::exit(), it will: 3944 // > release JNI handle blocks, remove stack guard pages 3945 // > remove this thread from Threads list 3946 // <-- no more Java code from this thread after this point --> 3947 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3948 // the compiler threads at safepoint 3949 // <-- do not use anything that could get blocked by Safepoint --> 3950 // + Disable tracing at JNI/JVM barriers 3951 // + Set _vm_exited flag for threads that are still running native code 3952 // + Delete this thread 3953 // + Call exit_globals() 3954 // > deletes tty 3955 // > deletes PerfMemory resources 3956 // + Return to caller 3957 3958 bool Threads::destroy_vm() { 3959 JavaThread* thread = JavaThread::current(); 3960 3961 #ifdef ASSERT 3962 _vm_complete = false; 3963 #endif 3964 // Wait until we are the last non-daemon thread to execute 3965 { MutexLocker nu(Threads_lock); 3966 while (Threads::number_of_non_daemon_threads() > 1 ) 3967 // This wait should make safepoint checks, wait without a timeout, 3968 // and wait as a suspend-equivalent condition. 3969 // 3970 // Note: If the FlatProfiler is running and this thread is waiting 3971 // for another non-daemon thread to finish, then the FlatProfiler 3972 // is waiting for the external suspend request on this thread to 3973 // complete. wait_for_ext_suspend_completion() will eventually 3974 // timeout, but that takes time. Making this wait a suspend- 3975 // equivalent condition solves that timeout problem. 3976 // 3977 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3978 Mutex::_as_suspend_equivalent_flag); 3979 } 3980 3981 // Hang forever on exit if we are reporting an error. 3982 if (ShowMessageBoxOnError && is_error_reported()) { 3983 os::infinite_sleep(); 3984 } 3985 os::wait_for_keypress_at_exit(); 3986 3987 if (JDK_Version::is_jdk12x_version()) { 3988 // We are the last thread running, so check if finalizers should be run. 3989 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3990 HandleMark rm(thread); 3991 Universe::run_finalizers_on_exit(); 3992 } else { 3993 // run Java level shutdown hooks 3994 thread->invoke_shutdown_hooks(); 3995 } 3996 3997 before_exit(thread); 3998 3999 thread->exit(true); 4000 4001 // Stop VM thread. 4002 { 4003 // 4945125 The vm thread comes to a safepoint during exit. 4004 // GC vm_operations can get caught at the safepoint, and the 4005 // heap is unparseable if they are caught. Grab the Heap_lock 4006 // to prevent this. The GC vm_operations will not be able to 4007 // queue until after the vm thread is dead. 4008 // After this point, we'll never emerge out of the safepoint before 4009 // the VM exits, so concurrent GC threads do not need to be explicitly 4010 // stopped; they remain inactive until the process exits. 4011 // Note: some concurrent G1 threads may be running during a safepoint, 4012 // but these will not be accessing the heap, just some G1-specific side 4013 // data structures that are not accessed by any other threads but them 4014 // after this point in a terminal safepoint. 4015 4016 MutexLocker ml(Heap_lock); 4017 4018 VMThread::wait_for_vm_thread_exit(); 4019 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4020 VMThread::destroy(); 4021 } 4022 4023 // clean up ideal graph printers 4024 #if defined(COMPILER2) && !defined(PRODUCT) 4025 IdealGraphPrinter::clean_up(); 4026 #endif 4027 4028 // Now, all Java threads are gone except daemon threads. Daemon threads 4029 // running Java code or in VM are stopped by the Safepoint. However, 4030 // daemon threads executing native code are still running. But they 4031 // will be stopped at native=>Java/VM barriers. Note that we can't 4032 // simply kill or suspend them, as it is inherently deadlock-prone. 4033 4034 #ifndef PRODUCT 4035 // disable function tracing at JNI/JVM barriers 4036 TraceJNICalls = false; 4037 TraceJVMCalls = false; 4038 TraceRuntimeCalls = false; 4039 #endif 4040 4041 VM_Exit::set_vm_exited(); 4042 4043 notify_vm_shutdown(); 4044 4045 delete thread; 4046 4047 // exit_globals() will delete tty 4048 exit_globals(); 4049 4050 return true; 4051 } 4052 4053 4054 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4055 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4056 return is_supported_jni_version(version); 4057 } 4058 4059 4060 jboolean Threads::is_supported_jni_version(jint version) { 4061 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4062 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4063 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4064 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4065 return JNI_FALSE; 4066 } 4067 4068 4069 void Threads::add(JavaThread* p, bool force_daemon) { 4070 // The threads lock must be owned at this point 4071 assert_locked_or_safepoint(Threads_lock); 4072 4073 // See the comment for this method in thread.hpp for its purpose and 4074 // why it is called here. 4075 p->initialize_queues(); 4076 p->set_next(_thread_list); 4077 _thread_list = p; 4078 _number_of_threads++; 4079 oop threadObj = p->threadObj(); 4080 bool daemon = true; 4081 // Bootstrapping problem: threadObj can be null for initial 4082 // JavaThread (or for threads attached via JNI) 4083 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4084 _number_of_non_daemon_threads++; 4085 daemon = false; 4086 } 4087 4088 p->set_safepoint_visible(true); 4089 4090 ThreadService::add_thread(p, daemon); 4091 4092 // Possible GC point. 4093 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4094 } 4095 4096 void Threads::remove(JavaThread* p) { 4097 // Extra scope needed for Thread_lock, so we can check 4098 // that we do not remove thread without safepoint code notice 4099 { MutexLocker ml(Threads_lock); 4100 4101 assert(includes(p), "p must be present"); 4102 4103 JavaThread* current = _thread_list; 4104 JavaThread* prev = NULL; 4105 4106 while (current != p) { 4107 prev = current; 4108 current = current->next(); 4109 } 4110 4111 if (prev) { 4112 prev->set_next(current->next()); 4113 } else { 4114 _thread_list = p->next(); 4115 } 4116 _number_of_threads--; 4117 oop threadObj = p->threadObj(); 4118 bool daemon = true; 4119 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4120 _number_of_non_daemon_threads--; 4121 daemon = false; 4122 4123 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4124 // on destroy_vm will wake up. 4125 if (number_of_non_daemon_threads() == 1) 4126 Threads_lock->notify_all(); 4127 } 4128 ThreadService::remove_thread(p, daemon); 4129 4130 // Make sure that safepoint code disregard this thread. This is needed since 4131 // the thread might mess around with locks after this point. This can cause it 4132 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4133 // of this thread since it is removed from the queue. 4134 p->set_terminated_value(); 4135 4136 // Now, this thread is not visible to safepoint 4137 p->set_safepoint_visible(false); 4138 // once the thread becomes safepoint invisible, we can not use its per-thread 4139 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4140 // to release its per-thread recorder here. 4141 MemTracker::thread_exiting(p); 4142 } // unlock Threads_lock 4143 4144 // Since Events::log uses a lock, we grab it outside the Threads_lock 4145 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4146 } 4147 4148 // Threads_lock must be held when this is called (or must be called during a safepoint) 4149 bool Threads::includes(JavaThread* p) { 4150 assert(Threads_lock->is_locked(), "sanity check"); 4151 ALL_JAVA_THREADS(q) { 4152 if (q == p ) { 4153 return true; 4154 } 4155 } 4156 return false; 4157 } 4158 4159 // Operations on the Threads list for GC. These are not explicitly locked, 4160 // but the garbage collector must provide a safe context for them to run. 4161 // In particular, these things should never be called when the Threads_lock 4162 // is held by some other thread. (Note: the Safepoint abstraction also 4163 // uses the Threads_lock to gurantee this property. It also makes sure that 4164 // all threads gets blocked when exiting or starting). 4165 4166 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4167 ALL_JAVA_THREADS(p) { 4168 p->oops_do(f, cld_f, cf); 4169 } 4170 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4171 } 4172 4173 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4174 // Introduce a mechanism allowing parallel threads to claim threads as 4175 // root groups. Overhead should be small enough to use all the time, 4176 // even in sequential code. 4177 SharedHeap* sh = SharedHeap::heap(); 4178 // Cannot yet substitute active_workers for n_par_threads 4179 // because of G1CollectedHeap::verify() use of 4180 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4181 // turn off parallelism in process_strong_roots while active_workers 4182 // is being used for parallelism elsewhere. 4183 bool is_par = sh->n_par_threads() > 0; 4184 assert(!is_par || 4185 (SharedHeap::heap()->n_par_threads() == 4186 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4187 int cp = SharedHeap::heap()->strong_roots_parity(); 4188 ALL_JAVA_THREADS(p) { 4189 if (p->claim_oops_do(is_par, cp)) { 4190 p->oops_do(f, cld_f, cf); 4191 } 4192 } 4193 VMThread* vmt = VMThread::vm_thread(); 4194 if (vmt->claim_oops_do(is_par, cp)) { 4195 vmt->oops_do(f, cld_f, cf); 4196 } 4197 } 4198 4199 #if INCLUDE_ALL_GCS 4200 // Used by ParallelScavenge 4201 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4202 ALL_JAVA_THREADS(p) { 4203 q->enqueue(new ThreadRootsTask(p)); 4204 } 4205 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4206 } 4207 4208 // Used by Parallel Old 4209 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4210 ALL_JAVA_THREADS(p) { 4211 q->enqueue(new ThreadRootsMarkingTask(p)); 4212 } 4213 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4214 } 4215 #endif // INCLUDE_ALL_GCS 4216 4217 void Threads::nmethods_do(CodeBlobClosure* cf) { 4218 ALL_JAVA_THREADS(p) { 4219 p->nmethods_do(cf); 4220 } 4221 VMThread::vm_thread()->nmethods_do(cf); 4222 } 4223 4224 void Threads::metadata_do(void f(Metadata*)) { 4225 ALL_JAVA_THREADS(p) { 4226 p->metadata_do(f); 4227 } 4228 } 4229 4230 void Threads::gc_epilogue() { 4231 ALL_JAVA_THREADS(p) { 4232 p->gc_epilogue(); 4233 } 4234 } 4235 4236 void Threads::gc_prologue() { 4237 ALL_JAVA_THREADS(p) { 4238 p->gc_prologue(); 4239 } 4240 } 4241 4242 void Threads::deoptimized_wrt_marked_nmethods() { 4243 ALL_JAVA_THREADS(p) { 4244 p->deoptimized_wrt_marked_nmethods(); 4245 } 4246 } 4247 4248 4249 // Get count Java threads that are waiting to enter the specified monitor. 4250 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4251 address monitor, bool doLock) { 4252 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4253 "must grab Threads_lock or be at safepoint"); 4254 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4255 4256 int i = 0; 4257 { 4258 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4259 ALL_JAVA_THREADS(p) { 4260 if (p->is_Compiler_thread()) continue; 4261 4262 address pending = (address)p->current_pending_monitor(); 4263 if (pending == monitor) { // found a match 4264 if (i < count) result->append(p); // save the first count matches 4265 i++; 4266 } 4267 } 4268 } 4269 return result; 4270 } 4271 4272 4273 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4274 assert(doLock || 4275 Threads_lock->owned_by_self() || 4276 SafepointSynchronize::is_at_safepoint(), 4277 "must grab Threads_lock or be at safepoint"); 4278 4279 // NULL owner means not locked so we can skip the search 4280 if (owner == NULL) return NULL; 4281 4282 { 4283 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4284 ALL_JAVA_THREADS(p) { 4285 // first, see if owner is the address of a Java thread 4286 if (owner == (address)p) return p; 4287 } 4288 } 4289 // Cannot assert on lack of success here since this function may be 4290 // used by code that is trying to report useful problem information 4291 // like deadlock detection. 4292 if (UseHeavyMonitors) return NULL; 4293 4294 // 4295 // If we didn't find a matching Java thread and we didn't force use of 4296 // heavyweight monitors, then the owner is the stack address of the 4297 // Lock Word in the owning Java thread's stack. 4298 // 4299 JavaThread* the_owner = NULL; 4300 { 4301 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4302 ALL_JAVA_THREADS(q) { 4303 if (q->is_lock_owned(owner)) { 4304 the_owner = q; 4305 break; 4306 } 4307 } 4308 } 4309 // cannot assert on lack of success here; see above comment 4310 return the_owner; 4311 } 4312 4313 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4314 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4315 char buf[32]; 4316 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4317 4318 st->print_cr("Full thread dump %s (%s %s):", 4319 Abstract_VM_Version::vm_name(), 4320 Abstract_VM_Version::vm_release(), 4321 Abstract_VM_Version::vm_info_string() 4322 ); 4323 st->cr(); 4324 4325 #if INCLUDE_ALL_GCS 4326 // Dump concurrent locks 4327 ConcurrentLocksDump concurrent_locks; 4328 if (print_concurrent_locks) { 4329 concurrent_locks.dump_at_safepoint(); 4330 } 4331 #endif // INCLUDE_ALL_GCS 4332 4333 ALL_JAVA_THREADS(p) { 4334 ResourceMark rm; 4335 p->print_on(st); 4336 if (print_stacks) { 4337 if (internal_format) { 4338 p->trace_stack(); 4339 } else { 4340 p->print_stack_on(st); 4341 } 4342 } 4343 st->cr(); 4344 #if INCLUDE_ALL_GCS 4345 if (print_concurrent_locks) { 4346 concurrent_locks.print_locks_on(p, st); 4347 } 4348 #endif // INCLUDE_ALL_GCS 4349 } 4350 4351 VMThread::vm_thread()->print_on(st); 4352 st->cr(); 4353 Universe::heap()->print_gc_threads_on(st); 4354 WatcherThread* wt = WatcherThread::watcher_thread(); 4355 if (wt != NULL) { 4356 wt->print_on(st); 4357 st->cr(); 4358 } 4359 CompileBroker::print_compiler_threads_on(st); 4360 st->flush(); 4361 } 4362 4363 // Threads::print_on_error() is called by fatal error handler. It's possible 4364 // that VM is not at safepoint and/or current thread is inside signal handler. 4365 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4366 // memory (even in resource area), it might deadlock the error handler. 4367 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4368 bool found_current = false; 4369 st->print_cr("Java Threads: ( => current thread )"); 4370 ALL_JAVA_THREADS(thread) { 4371 bool is_current = (current == thread); 4372 found_current = found_current || is_current; 4373 4374 st->print("%s", is_current ? "=>" : " "); 4375 4376 st->print(PTR_FORMAT, thread); 4377 st->print(" "); 4378 thread->print_on_error(st, buf, buflen); 4379 st->cr(); 4380 } 4381 st->cr(); 4382 4383 st->print_cr("Other Threads:"); 4384 if (VMThread::vm_thread()) { 4385 bool is_current = (current == VMThread::vm_thread()); 4386 found_current = found_current || is_current; 4387 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4388 4389 st->print(PTR_FORMAT, VMThread::vm_thread()); 4390 st->print(" "); 4391 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4392 st->cr(); 4393 } 4394 WatcherThread* wt = WatcherThread::watcher_thread(); 4395 if (wt != NULL) { 4396 bool is_current = (current == wt); 4397 found_current = found_current || is_current; 4398 st->print("%s", is_current ? "=>" : " "); 4399 4400 st->print(PTR_FORMAT, wt); 4401 st->print(" "); 4402 wt->print_on_error(st, buf, buflen); 4403 st->cr(); 4404 } 4405 if (!found_current) { 4406 st->cr(); 4407 st->print("=>" PTR_FORMAT " (exited) ", current); 4408 current->print_on_error(st, buf, buflen); 4409 st->cr(); 4410 } 4411 } 4412 4413 // Internal SpinLock and Mutex 4414 // Based on ParkEvent 4415 4416 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4417 // 4418 // We employ SpinLocks _only for low-contention, fixed-length 4419 // short-duration critical sections where we're concerned 4420 // about native mutex_t or HotSpot Mutex:: latency. 4421 // The mux construct provides a spin-then-block mutual exclusion 4422 // mechanism. 4423 // 4424 // Testing has shown that contention on the ListLock guarding gFreeList 4425 // is common. If we implement ListLock as a simple SpinLock it's common 4426 // for the JVM to devolve to yielding with little progress. This is true 4427 // despite the fact that the critical sections protected by ListLock are 4428 // extremely short. 4429 // 4430 // TODO-FIXME: ListLock should be of type SpinLock. 4431 // We should make this a 1st-class type, integrated into the lock 4432 // hierarchy as leaf-locks. Critically, the SpinLock structure 4433 // should have sufficient padding to avoid false-sharing and excessive 4434 // cache-coherency traffic. 4435 4436 4437 typedef volatile int SpinLockT ; 4438 4439 void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4440 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4441 return ; // normal fast-path return 4442 } 4443 4444 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4445 TEVENT (SpinAcquire - ctx) ; 4446 int ctr = 0 ; 4447 int Yields = 0 ; 4448 for (;;) { 4449 while (*adr != 0) { 4450 ++ctr ; 4451 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4452 if (Yields > 5) { 4453 // Consider using a simple NakedSleep() instead. 4454 // Then SpinAcquire could be called by non-JVM threads 4455 Thread::current()->_ParkEvent->park(1) ; 4456 } else { 4457 os::NakedYield() ; 4458 ++Yields ; 4459 } 4460 } else { 4461 SpinPause() ; 4462 } 4463 } 4464 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4465 } 4466 } 4467 4468 void Thread::SpinRelease (volatile int * adr) { 4469 assert (*adr != 0, "invariant") ; 4470 OrderAccess::fence() ; // guarantee at least release consistency. 4471 // Roach-motel semantics. 4472 // It's safe if subsequent LDs and STs float "up" into the critical section, 4473 // but prior LDs and STs within the critical section can't be allowed 4474 // to reorder or float past the ST that releases the lock. 4475 *adr = 0 ; 4476 } 4477 4478 // muxAcquire and muxRelease: 4479 // 4480 // * muxAcquire and muxRelease support a single-word lock-word construct. 4481 // The LSB of the word is set IFF the lock is held. 4482 // The remainder of the word points to the head of a singly-linked list 4483 // of threads blocked on the lock. 4484 // 4485 // * The current implementation of muxAcquire-muxRelease uses its own 4486 // dedicated Thread._MuxEvent instance. If we're interested in 4487 // minimizing the peak number of extant ParkEvent instances then 4488 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4489 // as certain invariants were satisfied. Specifically, care would need 4490 // to be taken with regards to consuming unpark() "permits". 4491 // A safe rule of thumb is that a thread would never call muxAcquire() 4492 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4493 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4494 // consume an unpark() permit intended for monitorenter, for instance. 4495 // One way around this would be to widen the restricted-range semaphore 4496 // implemented in park(). Another alternative would be to provide 4497 // multiple instances of the PlatformEvent() for each thread. One 4498 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4499 // 4500 // * Usage: 4501 // -- Only as leaf locks 4502 // -- for short-term locking only as muxAcquire does not perform 4503 // thread state transitions. 4504 // 4505 // Alternatives: 4506 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4507 // but with parking or spin-then-park instead of pure spinning. 4508 // * Use Taura-Oyama-Yonenzawa locks. 4509 // * It's possible to construct a 1-0 lock if we encode the lockword as 4510 // (List,LockByte). Acquire will CAS the full lockword while Release 4511 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4512 // acquiring threads use timers (ParkTimed) to detect and recover from 4513 // the stranding window. Thread/Node structures must be aligned on 256-byte 4514 // boundaries by using placement-new. 4515 // * Augment MCS with advisory back-link fields maintained with CAS(). 4516 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4517 // The validity of the backlinks must be ratified before we trust the value. 4518 // If the backlinks are invalid the exiting thread must back-track through the 4519 // the forward links, which are always trustworthy. 4520 // * Add a successor indication. The LockWord is currently encoded as 4521 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4522 // to provide the usual futile-wakeup optimization. 4523 // See RTStt for details. 4524 // * Consider schedctl.sc_nopreempt to cover the critical section. 4525 // 4526 4527 4528 typedef volatile intptr_t MutexT ; // Mux Lock-word 4529 enum MuxBits { LOCKBIT = 1 } ; 4530 4531 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4532 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4533 if (w == 0) return ; 4534 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4535 return ; 4536 } 4537 4538 TEVENT (muxAcquire - Contention) ; 4539 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4540 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4541 for (;;) { 4542 int its = (os::is_MP() ? 100 : 0) + 1 ; 4543 4544 // Optional spin phase: spin-then-park strategy 4545 while (--its >= 0) { 4546 w = *Lock ; 4547 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4548 return ; 4549 } 4550 } 4551 4552 Self->reset() ; 4553 Self->OnList = intptr_t(Lock) ; 4554 // The following fence() isn't _strictly necessary as the subsequent 4555 // CAS() both serializes execution and ratifies the fetched *Lock value. 4556 OrderAccess::fence(); 4557 for (;;) { 4558 w = *Lock ; 4559 if ((w & LOCKBIT) == 0) { 4560 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4561 Self->OnList = 0 ; // hygiene - allows stronger asserts 4562 return ; 4563 } 4564 continue ; // Interference -- *Lock changed -- Just retry 4565 } 4566 assert (w & LOCKBIT, "invariant") ; 4567 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4568 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4569 } 4570 4571 while (Self->OnList != 0) { 4572 Self->park() ; 4573 } 4574 } 4575 } 4576 4577 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4578 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4579 if (w == 0) return ; 4580 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4581 return ; 4582 } 4583 4584 TEVENT (muxAcquire - Contention) ; 4585 ParkEvent * ReleaseAfter = NULL ; 4586 if (ev == NULL) { 4587 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4588 } 4589 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4590 for (;;) { 4591 guarantee (ev->OnList == 0, "invariant") ; 4592 int its = (os::is_MP() ? 100 : 0) + 1 ; 4593 4594 // Optional spin phase: spin-then-park strategy 4595 while (--its >= 0) { 4596 w = *Lock ; 4597 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4598 if (ReleaseAfter != NULL) { 4599 ParkEvent::Release (ReleaseAfter) ; 4600 } 4601 return ; 4602 } 4603 } 4604 4605 ev->reset() ; 4606 ev->OnList = intptr_t(Lock) ; 4607 // The following fence() isn't _strictly necessary as the subsequent 4608 // CAS() both serializes execution and ratifies the fetched *Lock value. 4609 OrderAccess::fence(); 4610 for (;;) { 4611 w = *Lock ; 4612 if ((w & LOCKBIT) == 0) { 4613 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4614 ev->OnList = 0 ; 4615 // We call ::Release while holding the outer lock, thus 4616 // artificially lengthening the critical section. 4617 // Consider deferring the ::Release() until the subsequent unlock(), 4618 // after we've dropped the outer lock. 4619 if (ReleaseAfter != NULL) { 4620 ParkEvent::Release (ReleaseAfter) ; 4621 } 4622 return ; 4623 } 4624 continue ; // Interference -- *Lock changed -- Just retry 4625 } 4626 assert (w & LOCKBIT, "invariant") ; 4627 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4628 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4629 } 4630 4631 while (ev->OnList != 0) { 4632 ev->park() ; 4633 } 4634 } 4635 } 4636 4637 // Release() must extract a successor from the list and then wake that thread. 4638 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4639 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4640 // Release() would : 4641 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4642 // (B) Extract a successor from the private list "in-hand" 4643 // (C) attempt to CAS() the residual back into *Lock over null. 4644 // If there were any newly arrived threads and the CAS() would fail. 4645 // In that case Release() would detach the RATs, re-merge the list in-hand 4646 // with the RATs and repeat as needed. Alternately, Release() might 4647 // detach and extract a successor, but then pass the residual list to the wakee. 4648 // The wakee would be responsible for reattaching and remerging before it 4649 // competed for the lock. 4650 // 4651 // Both "pop" and DMR are immune from ABA corruption -- there can be 4652 // multiple concurrent pushers, but only one popper or detacher. 4653 // This implementation pops from the head of the list. This is unfair, 4654 // but tends to provide excellent throughput as hot threads remain hot. 4655 // (We wake recently run threads first). 4656 4657 void Thread::muxRelease (volatile intptr_t * Lock) { 4658 for (;;) { 4659 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4660 assert (w & LOCKBIT, "invariant") ; 4661 if (w == LOCKBIT) return ; 4662 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4663 assert (List != NULL, "invariant") ; 4664 assert (List->OnList == intptr_t(Lock), "invariant") ; 4665 ParkEvent * nxt = List->ListNext ; 4666 4667 // The following CAS() releases the lock and pops the head element. 4668 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4669 continue ; 4670 } 4671 List->OnList = 0 ; 4672 OrderAccess::fence() ; 4673 List->unpark () ; 4674 return ; 4675 } 4676 } 4677 4678 4679 void Threads::verify() { 4680 ALL_JAVA_THREADS(p) { 4681 p->verify(); 4682 } 4683 VMThread* thread = VMThread::vm_thread(); 4684 if (thread != NULL) thread->verify(); 4685 }