1 /* 2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/classLoader.hpp" 27 #include "classfile/javaClasses.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/scopeDesc.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "interpreter/interpreter.hpp" 33 #include "interpreter/linkResolver.hpp" 34 #include "interpreter/oopMapCache.hpp" 35 #include "jvmtifiles/jvmtiEnv.hpp" 36 #include "memory/gcLocker.inline.hpp" 37 #include "memory/metaspaceShared.hpp" 38 #include "memory/oopFactory.hpp" 39 #include "memory/universe.inline.hpp" 40 #include "oops/instanceKlass.hpp" 41 #include "oops/objArrayOop.hpp" 42 #include "oops/oop.inline.hpp" 43 #include "oops/symbol.hpp" 44 #include "prims/jvm_misc.hpp" 45 #include "prims/jvmtiExport.hpp" 46 #include "prims/jvmtiThreadState.hpp" 47 #include "prims/privilegedStack.hpp" 48 #include "runtime/arguments.hpp" 49 #include "runtime/atomic.inline.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/orderAccess.inline.hpp" 63 #include "runtime/osThread.hpp" 64 #include "runtime/safepoint.hpp" 65 #include "runtime/sharedRuntime.hpp" 66 #include "runtime/statSampler.hpp" 67 #include "runtime/stubRoutines.hpp" 68 #include "runtime/task.hpp" 69 #include "runtime/thread.inline.hpp" 70 #include "runtime/threadCritical.hpp" 71 #include "runtime/threadLocalStorage.hpp" 72 #include "runtime/vframe.hpp" 73 #include "runtime/vframeArray.hpp" 74 #include "runtime/vframe_hp.hpp" 75 #include "runtime/vmThread.hpp" 76 #include "runtime/vm_operations.hpp" 77 #include "services/attachListener.hpp" 78 #include "services/management.hpp" 79 #include "services/memTracker.hpp" 80 #include "services/threadService.hpp" 81 #include "trace/tracing.hpp" 82 #include "trace/traceMacros.hpp" 83 #include "utilities/defaultStream.hpp" 84 #include "utilities/dtrace.hpp" 85 #include "utilities/events.hpp" 86 #include "utilities/preserveException.hpp" 87 #include "utilities/macros.hpp" 88 #ifdef TARGET_OS_FAMILY_linux 89 # include "os_linux.inline.hpp" 90 #endif 91 #ifdef TARGET_OS_FAMILY_solaris 92 # include "os_solaris.inline.hpp" 93 #endif 94 #ifdef TARGET_OS_FAMILY_windows 95 # include "os_windows.inline.hpp" 96 #endif 97 #ifdef TARGET_OS_FAMILY_bsd 98 # include "os_bsd.inline.hpp" 99 #endif 100 #if INCLUDE_ALL_GCS 101 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 102 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 103 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 104 #endif // INCLUDE_ALL_GCS 105 #ifdef COMPILER1 106 #include "c1/c1_Compiler.hpp" 107 #endif 108 #ifdef COMPILER2 109 #include "opto/c2compiler.hpp" 110 #include "opto/idealGraphPrinter.hpp" 111 #endif 112 #if INCLUDE_RTM_OPT 113 #include "runtime/rtmLocking.hpp" 114 #endif 115 116 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 117 118 #ifdef DTRACE_ENABLED 119 120 // Only bother with this argument setup if dtrace is available 121 122 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 123 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 124 125 #define DTRACE_THREAD_PROBE(probe, javathread) \ 126 { \ 127 ResourceMark rm(this); \ 128 int len = 0; \ 129 const char* name = (javathread)->get_thread_name(); \ 130 len = strlen(name); \ 131 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 132 (char *) name, len, \ 133 java_lang_Thread::thread_id((javathread)->threadObj()), \ 134 (uintptr_t) (javathread)->osthread()->thread_id(), \ 135 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 136 } 137 138 #else // ndef DTRACE_ENABLED 139 140 #define DTRACE_THREAD_PROBE(probe, javathread) 141 142 #endif // ndef DTRACE_ENABLED 143 144 145 // Class hierarchy 146 // - Thread 147 // - VMThread 148 // - WatcherThread 149 // - ConcurrentMarkSweepThread 150 // - JavaThread 151 // - CompilerThread 152 153 // ======= Thread ======== 154 // Support for forcing alignment of thread objects for biased locking 155 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 156 if (UseBiasedLocking) { 157 const int alignment = markOopDesc::biased_lock_alignment; 158 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 159 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 160 : AllocateHeap(aligned_size, flags, CURRENT_PC, 161 AllocFailStrategy::RETURN_NULL); 162 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 163 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 164 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 165 "JavaThread alignment code overflowed allocated storage"); 166 if (TraceBiasedLocking) { 167 if (aligned_addr != real_malloc_addr) 168 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 169 real_malloc_addr, aligned_addr); 170 } 171 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 172 return aligned_addr; 173 } else { 174 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 175 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 176 } 177 } 178 179 void Thread::operator delete(void* p) { 180 if (UseBiasedLocking) { 181 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 182 FreeHeap(real_malloc_addr, mtThread); 183 } else { 184 FreeHeap(p, mtThread); 185 } 186 } 187 188 189 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 190 // JavaThread 191 192 193 Thread::Thread() { 194 // stack and get_thread 195 set_stack_base(NULL); 196 set_stack_size(0); 197 set_self_raw_id(0); 198 set_lgrp_id(-1); 199 200 // allocated data structures 201 set_osthread(NULL); 202 set_resource_area(new (mtThread)ResourceArea()); 203 DEBUG_ONLY(_current_resource_mark = NULL;) 204 set_handle_area(new (mtThread) HandleArea(NULL)); 205 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 206 set_active_handles(NULL); 207 set_free_handle_block(NULL); 208 set_last_handle_mark(NULL); 209 210 // This initial value ==> never claimed. 211 _oops_do_parity = 0; 212 213 // the handle mark links itself to last_handle_mark 214 new HandleMark(this); 215 216 // plain initialization 217 debug_only(_owned_locks = NULL;) 218 debug_only(_allow_allocation_count = 0;) 219 NOT_PRODUCT(_allow_safepoint_count = 0;) 220 NOT_PRODUCT(_skip_gcalot = false;) 221 _jvmti_env_iteration_count = 0; 222 set_allocated_bytes(0); 223 _vm_operation_started_count = 0; 224 _vm_operation_completed_count = 0; 225 _current_pending_monitor = NULL; 226 _current_pending_monitor_is_from_java = true; 227 _current_waiting_monitor = NULL; 228 _num_nested_signal = 0; 229 omFreeList = NULL ; 230 omFreeCount = 0 ; 231 omFreeProvision = 32 ; 232 omInUseList = NULL ; 233 omInUseCount = 0 ; 234 235 #ifdef ASSERT 236 _visited_for_critical_count = false; 237 #endif 238 239 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 240 _suspend_flags = 0; 241 242 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 243 _hashStateX = os::random() ; 244 _hashStateY = 842502087 ; 245 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 246 _hashStateW = 273326509 ; 247 248 _OnTrap = 0 ; 249 _schedctl = NULL ; 250 _Stalled = 0 ; 251 _TypeTag = 0x2BAD ; 252 253 // Many of the following fields are effectively final - immutable 254 // Note that nascent threads can't use the Native Monitor-Mutex 255 // construct until the _MutexEvent is initialized ... 256 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 257 // we might instead use a stack of ParkEvents that we could provision on-demand. 258 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 259 // and ::Release() 260 _ParkEvent = ParkEvent::Allocate (this) ; 261 _SleepEvent = ParkEvent::Allocate (this) ; 262 _MutexEvent = ParkEvent::Allocate (this) ; 263 _MuxEvent = ParkEvent::Allocate (this) ; 264 265 #ifdef CHECK_UNHANDLED_OOPS 266 if (CheckUnhandledOops) { 267 _unhandled_oops = new UnhandledOops(this); 268 } 269 #endif // CHECK_UNHANDLED_OOPS 270 #ifdef ASSERT 271 if (UseBiasedLocking) { 272 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 273 assert(this == _real_malloc_address || 274 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 275 "bug in forced alignment of thread objects"); 276 } 277 #endif /* ASSERT */ 278 } 279 280 void Thread::initialize_thread_local_storage() { 281 // Note: Make sure this method only calls 282 // non-blocking operations. Otherwise, it might not work 283 // with the thread-startup/safepoint interaction. 284 285 // During Java thread startup, safepoint code should allow this 286 // method to complete because it may need to allocate memory to 287 // store information for the new thread. 288 289 // initialize structure dependent on thread local storage 290 ThreadLocalStorage::set_thread(this); 291 } 292 293 void Thread::record_stack_base_and_size() { 294 set_stack_base(os::current_stack_base()); 295 set_stack_size(os::current_stack_size()); 296 if (is_Java_thread()) { 297 ((JavaThread*) this)->set_stack_overflow_limit(); 298 } 299 // CR 7190089: on Solaris, primordial thread's stack is adjusted 300 // in initialize_thread(). Without the adjustment, stack size is 301 // incorrect if stack is set to unlimited (ulimit -s unlimited). 302 // So far, only Solaris has real implementation of initialize_thread(). 303 // 304 // set up any platform-specific state. 305 os::initialize_thread(this); 306 307 #if INCLUDE_NMT 308 // record thread's native stack, stack grows downward 309 address stack_low_addr = stack_base() - stack_size(); 310 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 311 CURRENT_PC); 312 #endif // INCLUDE_NMT 313 } 314 315 316 Thread::~Thread() { 317 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 318 ObjectSynchronizer::omFlush (this) ; 319 320 EVENT_THREAD_DESTRUCT(this); 321 322 // stack_base can be NULL if the thread is never started or exited before 323 // record_stack_base_and_size called. Although, we would like to ensure 324 // that all started threads do call record_stack_base_and_size(), there is 325 // not proper way to enforce that. 326 #if INCLUDE_NMT 327 if (_stack_base != NULL) { 328 address low_stack_addr = stack_base() - stack_size(); 329 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); 330 #ifdef ASSERT 331 set_stack_base(NULL); 332 #endif 333 } 334 #endif // INCLUDE_NMT 335 336 // deallocate data structures 337 delete resource_area(); 338 // since the handle marks are using the handle area, we have to deallocated the root 339 // handle mark before deallocating the thread's handle area, 340 assert(last_handle_mark() != NULL, "check we have an element"); 341 delete last_handle_mark(); 342 assert(last_handle_mark() == NULL, "check we have reached the end"); 343 344 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 345 // We NULL out the fields for good hygiene. 346 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 347 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 348 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 349 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 350 351 delete handle_area(); 352 delete metadata_handles(); 353 354 // osthread() can be NULL, if creation of thread failed. 355 if (osthread() != NULL) os::free_thread(osthread()); 356 357 delete _SR_lock; 358 359 // clear thread local storage if the Thread is deleting itself 360 if (this == Thread::current()) { 361 ThreadLocalStorage::set_thread(NULL); 362 } else { 363 // In the case where we're not the current thread, invalidate all the 364 // caches in case some code tries to get the current thread or the 365 // thread that was destroyed, and gets stale information. 366 ThreadLocalStorage::invalidate_all(); 367 } 368 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 369 } 370 371 // NOTE: dummy function for assertion purpose. 372 void Thread::run() { 373 ShouldNotReachHere(); 374 } 375 376 #ifdef ASSERT 377 // Private method to check for dangling thread pointer 378 void check_for_dangling_thread_pointer(Thread *thread) { 379 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 380 "possibility of dangling Thread pointer"); 381 } 382 #endif 383 384 385 #ifndef PRODUCT 386 // Tracing method for basic thread operations 387 void Thread::trace(const char* msg, const Thread* const thread) { 388 if (!TraceThreadEvents) return; 389 ResourceMark rm; 390 ThreadCritical tc; 391 const char *name = "non-Java thread"; 392 int prio = -1; 393 if (thread->is_Java_thread() 394 && !thread->is_Compiler_thread()) { 395 // The Threads_lock must be held to get information about 396 // this thread but may not be in some situations when 397 // tracing thread events. 398 bool release_Threads_lock = false; 399 if (!Threads_lock->owned_by_self()) { 400 Threads_lock->lock(); 401 release_Threads_lock = true; 402 } 403 JavaThread* jt = (JavaThread *)thread; 404 name = (char *)jt->get_thread_name(); 405 oop thread_oop = jt->threadObj(); 406 if (thread_oop != NULL) { 407 prio = java_lang_Thread::priority(thread_oop); 408 } 409 if (release_Threads_lock) { 410 Threads_lock->unlock(); 411 } 412 } 413 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 414 } 415 #endif 416 417 418 ThreadPriority Thread::get_priority(const Thread* const thread) { 419 trace("get priority", thread); 420 ThreadPriority priority; 421 // Can return an error! 422 (void)os::get_priority(thread, priority); 423 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 424 return priority; 425 } 426 427 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 428 trace("set priority", thread); 429 debug_only(check_for_dangling_thread_pointer(thread);) 430 // Can return an error! 431 (void)os::set_priority(thread, priority); 432 } 433 434 435 void Thread::start(Thread* thread) { 436 trace("start", thread); 437 // Start is different from resume in that its safety is guaranteed by context or 438 // being called from a Java method synchronized on the Thread object. 439 if (!DisableStartThread) { 440 if (thread->is_Java_thread()) { 441 // Initialize the thread state to RUNNABLE before starting this thread. 442 // Can not set it after the thread started because we do not know the 443 // exact thread state at that time. It could be in MONITOR_WAIT or 444 // in SLEEPING or some other state. 445 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 446 java_lang_Thread::RUNNABLE); 447 } 448 os::start_thread(thread); 449 } 450 } 451 452 // Enqueue a VM_Operation to do the job for us - sometime later 453 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 454 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 455 VMThread::execute(vm_stop); 456 } 457 458 459 // 460 // Check if an external suspend request has completed (or has been 461 // cancelled). Returns true if the thread is externally suspended and 462 // false otherwise. 463 // 464 // The bits parameter returns information about the code path through 465 // the routine. Useful for debugging: 466 // 467 // set in is_ext_suspend_completed(): 468 // 0x00000001 - routine was entered 469 // 0x00000010 - routine return false at end 470 // 0x00000100 - thread exited (return false) 471 // 0x00000200 - suspend request cancelled (return false) 472 // 0x00000400 - thread suspended (return true) 473 // 0x00001000 - thread is in a suspend equivalent state (return true) 474 // 0x00002000 - thread is native and walkable (return true) 475 // 0x00004000 - thread is native_trans and walkable (needed retry) 476 // 477 // set in wait_for_ext_suspend_completion(): 478 // 0x00010000 - routine was entered 479 // 0x00020000 - suspend request cancelled before loop (return false) 480 // 0x00040000 - thread suspended before loop (return true) 481 // 0x00080000 - suspend request cancelled in loop (return false) 482 // 0x00100000 - thread suspended in loop (return true) 483 // 0x00200000 - suspend not completed during retry loop (return false) 484 // 485 486 // Helper class for tracing suspend wait debug bits. 487 // 488 // 0x00000100 indicates that the target thread exited before it could 489 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 490 // 0x00080000 each indicate a cancelled suspend request so they don't 491 // count as wait failures either. 492 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 493 494 class TraceSuspendDebugBits : public StackObj { 495 private: 496 JavaThread * jt; 497 bool is_wait; 498 bool called_by_wait; // meaningful when !is_wait 499 uint32_t * bits; 500 501 public: 502 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 503 uint32_t *_bits) { 504 jt = _jt; 505 is_wait = _is_wait; 506 called_by_wait = _called_by_wait; 507 bits = _bits; 508 } 509 510 ~TraceSuspendDebugBits() { 511 if (!is_wait) { 512 #if 1 513 // By default, don't trace bits for is_ext_suspend_completed() calls. 514 // That trace is very chatty. 515 return; 516 #else 517 if (!called_by_wait) { 518 // If tracing for is_ext_suspend_completed() is enabled, then only 519 // trace calls to it from wait_for_ext_suspend_completion() 520 return; 521 } 522 #endif 523 } 524 525 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 526 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 527 MutexLocker ml(Threads_lock); // needed for get_thread_name() 528 ResourceMark rm; 529 530 tty->print_cr( 531 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 532 jt->get_thread_name(), *bits); 533 534 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 535 } 536 } 537 } 538 }; 539 #undef DEBUG_FALSE_BITS 540 541 542 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 543 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 544 545 bool did_trans_retry = false; // only do thread_in_native_trans retry once 546 bool do_trans_retry; // flag to force the retry 547 548 *bits |= 0x00000001; 549 550 do { 551 do_trans_retry = false; 552 553 if (is_exiting()) { 554 // Thread is in the process of exiting. This is always checked 555 // first to reduce the risk of dereferencing a freed JavaThread. 556 *bits |= 0x00000100; 557 return false; 558 } 559 560 if (!is_external_suspend()) { 561 // Suspend request is cancelled. This is always checked before 562 // is_ext_suspended() to reduce the risk of a rogue resume 563 // confusing the thread that made the suspend request. 564 *bits |= 0x00000200; 565 return false; 566 } 567 568 if (is_ext_suspended()) { 569 // thread is suspended 570 *bits |= 0x00000400; 571 return true; 572 } 573 574 // Now that we no longer do hard suspends of threads running 575 // native code, the target thread can be changing thread state 576 // while we are in this routine: 577 // 578 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 579 // 580 // We save a copy of the thread state as observed at this moment 581 // and make our decision about suspend completeness based on the 582 // copy. This closes the race where the thread state is seen as 583 // _thread_in_native_trans in the if-thread_blocked check, but is 584 // seen as _thread_blocked in if-thread_in_native_trans check. 585 JavaThreadState save_state = thread_state(); 586 587 if (save_state == _thread_blocked && is_suspend_equivalent()) { 588 // If the thread's state is _thread_blocked and this blocking 589 // condition is known to be equivalent to a suspend, then we can 590 // consider the thread to be externally suspended. This means that 591 // the code that sets _thread_blocked has been modified to do 592 // self-suspension if the blocking condition releases. We also 593 // used to check for CONDVAR_WAIT here, but that is now covered by 594 // the _thread_blocked with self-suspension check. 595 // 596 // Return true since we wouldn't be here unless there was still an 597 // external suspend request. 598 *bits |= 0x00001000; 599 return true; 600 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 601 // Threads running native code will self-suspend on native==>VM/Java 602 // transitions. If its stack is walkable (should always be the case 603 // unless this function is called before the actual java_suspend() 604 // call), then the wait is done. 605 *bits |= 0x00002000; 606 return true; 607 } else if (!called_by_wait && !did_trans_retry && 608 save_state == _thread_in_native_trans && 609 frame_anchor()->walkable()) { 610 // The thread is transitioning from thread_in_native to another 611 // thread state. check_safepoint_and_suspend_for_native_trans() 612 // will force the thread to self-suspend. If it hasn't gotten 613 // there yet we may have caught the thread in-between the native 614 // code check above and the self-suspend. Lucky us. If we were 615 // called by wait_for_ext_suspend_completion(), then it 616 // will be doing the retries so we don't have to. 617 // 618 // Since we use the saved thread state in the if-statement above, 619 // there is a chance that the thread has already transitioned to 620 // _thread_blocked by the time we get here. In that case, we will 621 // make a single unnecessary pass through the logic below. This 622 // doesn't hurt anything since we still do the trans retry. 623 624 *bits |= 0x00004000; 625 626 // Once the thread leaves thread_in_native_trans for another 627 // thread state, we break out of this retry loop. We shouldn't 628 // need this flag to prevent us from getting back here, but 629 // sometimes paranoia is good. 630 did_trans_retry = true; 631 632 // We wait for the thread to transition to a more usable state. 633 for (int i = 1; i <= SuspendRetryCount; i++) { 634 // We used to do an "os::yield_all(i)" call here with the intention 635 // that yielding would increase on each retry. However, the parameter 636 // is ignored on Linux which means the yield didn't scale up. Waiting 637 // on the SR_lock below provides a much more predictable scale up for 638 // the delay. It also provides a simple/direct point to check for any 639 // safepoint requests from the VMThread 640 641 // temporarily drops SR_lock while doing wait with safepoint check 642 // (if we're a JavaThread - the WatcherThread can also call this) 643 // and increase delay with each retry 644 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 645 646 // check the actual thread state instead of what we saved above 647 if (thread_state() != _thread_in_native_trans) { 648 // the thread has transitioned to another thread state so 649 // try all the checks (except this one) one more time. 650 do_trans_retry = true; 651 break; 652 } 653 } // end retry loop 654 655 656 } 657 } while (do_trans_retry); 658 659 *bits |= 0x00000010; 660 return false; 661 } 662 663 // 664 // Wait for an external suspend request to complete (or be cancelled). 665 // Returns true if the thread is externally suspended and false otherwise. 666 // 667 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 668 uint32_t *bits) { 669 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 670 false /* !called_by_wait */, bits); 671 672 // local flag copies to minimize SR_lock hold time 673 bool is_suspended; 674 bool pending; 675 uint32_t reset_bits; 676 677 // set a marker so is_ext_suspend_completed() knows we are the caller 678 *bits |= 0x00010000; 679 680 // We use reset_bits to reinitialize the bits value at the top of 681 // each retry loop. This allows the caller to make use of any 682 // unused bits for their own marking purposes. 683 reset_bits = *bits; 684 685 { 686 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 687 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 688 delay, bits); 689 pending = is_external_suspend(); 690 } 691 // must release SR_lock to allow suspension to complete 692 693 if (!pending) { 694 // A cancelled suspend request is the only false return from 695 // is_ext_suspend_completed() that keeps us from entering the 696 // retry loop. 697 *bits |= 0x00020000; 698 return false; 699 } 700 701 if (is_suspended) { 702 *bits |= 0x00040000; 703 return true; 704 } 705 706 for (int i = 1; i <= retries; i++) { 707 *bits = reset_bits; // reinit to only track last retry 708 709 // We used to do an "os::yield_all(i)" call here with the intention 710 // that yielding would increase on each retry. However, the parameter 711 // is ignored on Linux which means the yield didn't scale up. Waiting 712 // on the SR_lock below provides a much more predictable scale up for 713 // the delay. It also provides a simple/direct point to check for any 714 // safepoint requests from the VMThread 715 716 { 717 MutexLocker ml(SR_lock()); 718 // wait with safepoint check (if we're a JavaThread - the WatcherThread 719 // can also call this) and increase delay with each retry 720 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 721 722 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 723 delay, bits); 724 725 // It is possible for the external suspend request to be cancelled 726 // (by a resume) before the actual suspend operation is completed. 727 // Refresh our local copy to see if we still need to wait. 728 pending = is_external_suspend(); 729 } 730 731 if (!pending) { 732 // A cancelled suspend request is the only false return from 733 // is_ext_suspend_completed() that keeps us from staying in the 734 // retry loop. 735 *bits |= 0x00080000; 736 return false; 737 } 738 739 if (is_suspended) { 740 *bits |= 0x00100000; 741 return true; 742 } 743 } // end retry loop 744 745 // thread did not suspend after all our retries 746 *bits |= 0x00200000; 747 return false; 748 } 749 750 #ifndef PRODUCT 751 void JavaThread::record_jump(address target, address instr, const char* file, int line) { 752 753 // This should not need to be atomic as the only way for simultaneous 754 // updates is via interrupts. Even then this should be rare or non-existent 755 // and we don't care that much anyway. 756 757 int index = _jmp_ring_index; 758 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 759 _jmp_ring[index]._target = (intptr_t) target; 760 _jmp_ring[index]._instruction = (intptr_t) instr; 761 _jmp_ring[index]._file = file; 762 _jmp_ring[index]._line = line; 763 } 764 #endif /* PRODUCT */ 765 766 // Called by flat profiler 767 // Callers have already called wait_for_ext_suspend_completion 768 // The assertion for that is currently too complex to put here: 769 bool JavaThread::profile_last_Java_frame(frame* _fr) { 770 bool gotframe = false; 771 // self suspension saves needed state. 772 if (has_last_Java_frame() && _anchor.walkable()) { 773 *_fr = pd_last_frame(); 774 gotframe = true; 775 } 776 return gotframe; 777 } 778 779 void Thread::interrupt(Thread* thread) { 780 trace("interrupt", thread); 781 debug_only(check_for_dangling_thread_pointer(thread);) 782 os::interrupt(thread); 783 } 784 785 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 786 trace("is_interrupted", thread); 787 debug_only(check_for_dangling_thread_pointer(thread);) 788 // Note: If clear_interrupted==false, this simply fetches and 789 // returns the value of the field osthread()->interrupted(). 790 return os::is_interrupted(thread, clear_interrupted); 791 } 792 793 794 // GC Support 795 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 796 jint thread_parity = _oops_do_parity; 797 if (thread_parity != strong_roots_parity) { 798 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 799 if (res == thread_parity) { 800 return true; 801 } else { 802 guarantee(res == strong_roots_parity, "Or else what?"); 803 assert(SharedHeap::heap()->workers()->active_workers() > 0, 804 "Should only fail when parallel."); 805 return false; 806 } 807 } 808 assert(SharedHeap::heap()->workers()->active_workers() > 0, 809 "Should only fail when parallel."); 810 return false; 811 } 812 813 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 814 active_handles()->oops_do(f); 815 // Do oop for ThreadShadow 816 f->do_oop((oop*)&_pending_exception); 817 handle_area()->oops_do(f); 818 } 819 820 void Thread::nmethods_do(CodeBlobClosure* cf) { 821 // no nmethods in a generic thread... 822 } 823 824 void Thread::metadata_do(void f(Metadata*)) { 825 if (metadata_handles() != NULL) { 826 for (int i = 0; i< metadata_handles()->length(); i++) { 827 f(metadata_handles()->at(i)); 828 } 829 } 830 } 831 832 void Thread::print_on(outputStream* st) const { 833 // get_priority assumes osthread initialized 834 if (osthread() != NULL) { 835 int os_prio; 836 if (os::get_native_priority(this, &os_prio) == OS_OK) { 837 st->print("os_prio=%d ", os_prio); 838 } 839 st->print("tid=" INTPTR_FORMAT " ", this); 840 osthread()->print_on(st); 841 } 842 debug_only(if (WizardMode) print_owned_locks_on(st);) 843 } 844 845 // Thread::print_on_error() is called by fatal error handler. Don't use 846 // any lock or allocate memory. 847 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 848 if (is_VM_thread()) st->print("VMThread"); 849 else if (is_Compiler_thread()) st->print("CompilerThread"); 850 else if (is_Java_thread()) st->print("JavaThread"); 851 else if (is_GC_task_thread()) st->print("GCTaskThread"); 852 else if (is_Watcher_thread()) st->print("WatcherThread"); 853 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 854 else st->print("Thread"); 855 856 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 857 _stack_base - _stack_size, _stack_base); 858 859 if (osthread()) { 860 st->print(" [id=%d]", osthread()->thread_id()); 861 } 862 } 863 864 #ifdef ASSERT 865 void Thread::print_owned_locks_on(outputStream* st) const { 866 Monitor *cur = _owned_locks; 867 if (cur == NULL) { 868 st->print(" (no locks) "); 869 } else { 870 st->print_cr(" Locks owned:"); 871 while(cur) { 872 cur->print_on(st); 873 cur = cur->next(); 874 } 875 } 876 } 877 878 static int ref_use_count = 0; 879 880 bool Thread::owns_locks_but_compiled_lock() const { 881 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 882 if (cur != Compile_lock) return true; 883 } 884 return false; 885 } 886 887 888 #endif 889 890 #ifndef PRODUCT 891 892 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 893 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 894 // no threads which allow_vm_block's are held 895 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 896 // Check if current thread is allowed to block at a safepoint 897 if (!(_allow_safepoint_count == 0)) 898 fatal("Possible safepoint reached by thread that does not allow it"); 899 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 900 fatal("LEAF method calling lock?"); 901 } 902 903 #ifdef ASSERT 904 if (potential_vm_operation && is_Java_thread() 905 && !Universe::is_bootstrapping()) { 906 // Make sure we do not hold any locks that the VM thread also uses. 907 // This could potentially lead to deadlocks 908 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 909 // Threads_lock is special, since the safepoint synchronization will not start before this is 910 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 911 // since it is used to transfer control between JavaThreads and the VMThread 912 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 913 if ( (cur->allow_vm_block() && 914 cur != Threads_lock && 915 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 916 cur != VMOperationRequest_lock && 917 cur != VMOperationQueue_lock) || 918 cur->rank() == Mutex::special) { 919 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name())); 920 } 921 } 922 } 923 924 if (GCALotAtAllSafepoints) { 925 // We could enter a safepoint here and thus have a gc 926 InterfaceSupport::check_gc_alot(); 927 } 928 #endif 929 } 930 #endif 931 932 bool Thread::is_in_stack(address adr) const { 933 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 934 address end = os::current_stack_pointer(); 935 // Allow non Java threads to call this without stack_base 936 if (_stack_base == NULL) return true; 937 if (stack_base() >= adr && adr >= end) return true; 938 939 return false; 940 } 941 942 943 bool Thread::is_in_usable_stack(address adr) const { 944 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 945 size_t usable_stack_size = _stack_size - stack_guard_size; 946 947 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 948 } 949 950 951 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 952 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 953 // used for compilation in the future. If that change is made, the need for these methods 954 // should be revisited, and they should be removed if possible. 955 956 bool Thread::is_lock_owned(address adr) const { 957 return on_local_stack(adr); 958 } 959 960 bool Thread::set_as_starting_thread() { 961 // NOTE: this must be called inside the main thread. 962 return os::create_main_thread((JavaThread*)this); 963 } 964 965 static void initialize_class(Symbol* class_name, TRAPS) { 966 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 967 InstanceKlass::cast(klass)->initialize(CHECK); 968 } 969 970 971 // Creates the initial ThreadGroup 972 static Handle create_initial_thread_group(TRAPS) { 973 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 974 instanceKlassHandle klass (THREAD, k); 975 976 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 977 { 978 JavaValue result(T_VOID); 979 JavaCalls::call_special(&result, 980 system_instance, 981 klass, 982 vmSymbols::object_initializer_name(), 983 vmSymbols::void_method_signature(), 984 CHECK_NH); 985 } 986 Universe::set_system_thread_group(system_instance()); 987 988 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 989 { 990 JavaValue result(T_VOID); 991 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 992 JavaCalls::call_special(&result, 993 main_instance, 994 klass, 995 vmSymbols::object_initializer_name(), 996 vmSymbols::threadgroup_string_void_signature(), 997 system_instance, 998 string, 999 CHECK_NH); 1000 } 1001 return main_instance; 1002 } 1003 1004 // Creates the initial Thread 1005 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1006 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1007 instanceKlassHandle klass (THREAD, k); 1008 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1009 1010 java_lang_Thread::set_thread(thread_oop(), thread); 1011 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1012 thread->set_threadObj(thread_oop()); 1013 1014 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1015 1016 JavaValue result(T_VOID); 1017 JavaCalls::call_special(&result, thread_oop, 1018 klass, 1019 vmSymbols::object_initializer_name(), 1020 vmSymbols::threadgroup_string_void_signature(), 1021 thread_group, 1022 string, 1023 CHECK_NULL); 1024 return thread_oop(); 1025 } 1026 1027 static void call_initializeSystemClass(TRAPS) { 1028 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1029 instanceKlassHandle klass (THREAD, k); 1030 1031 JavaValue result(T_VOID); 1032 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1033 vmSymbols::void_method_signature(), CHECK); 1034 } 1035 1036 char java_runtime_name[128] = ""; 1037 char java_runtime_version[128] = ""; 1038 1039 // extract the JRE name from sun.misc.Version.java_runtime_name 1040 static const char* get_java_runtime_name(TRAPS) { 1041 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1042 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1043 fieldDescriptor fd; 1044 bool found = k != NULL && 1045 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1046 vmSymbols::string_signature(), &fd); 1047 if (found) { 1048 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1049 if (name_oop == NULL) 1050 return NULL; 1051 const char* name = java_lang_String::as_utf8_string(name_oop, 1052 java_runtime_name, 1053 sizeof(java_runtime_name)); 1054 return name; 1055 } else { 1056 return NULL; 1057 } 1058 } 1059 1060 // extract the JRE version from sun.misc.Version.java_runtime_version 1061 static const char* get_java_runtime_version(TRAPS) { 1062 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1063 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1064 fieldDescriptor fd; 1065 bool found = k != NULL && 1066 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1067 vmSymbols::string_signature(), &fd); 1068 if (found) { 1069 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1070 if (name_oop == NULL) 1071 return NULL; 1072 const char* name = java_lang_String::as_utf8_string(name_oop, 1073 java_runtime_version, 1074 sizeof(java_runtime_version)); 1075 return name; 1076 } else { 1077 return NULL; 1078 } 1079 } 1080 1081 // General purpose hook into Java code, run once when the VM is initialized. 1082 // The Java library method itself may be changed independently from the VM. 1083 static void call_postVMInitHook(TRAPS) { 1084 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1085 instanceKlassHandle klass (THREAD, k); 1086 if (klass.not_null()) { 1087 JavaValue result(T_VOID); 1088 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1089 vmSymbols::void_method_signature(), 1090 CHECK); 1091 } 1092 } 1093 1094 static void reset_vm_info_property(TRAPS) { 1095 // the vm info string 1096 ResourceMark rm(THREAD); 1097 const char *vm_info = VM_Version::vm_info_string(); 1098 1099 // java.lang.System class 1100 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1101 instanceKlassHandle klass (THREAD, k); 1102 1103 // setProperty arguments 1104 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1105 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1106 1107 // return value 1108 JavaValue r(T_OBJECT); 1109 1110 // public static String setProperty(String key, String value); 1111 JavaCalls::call_static(&r, 1112 klass, 1113 vmSymbols::setProperty_name(), 1114 vmSymbols::string_string_string_signature(), 1115 key_str, 1116 value_str, 1117 CHECK); 1118 } 1119 1120 1121 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1122 assert(thread_group.not_null(), "thread group should be specified"); 1123 assert(threadObj() == NULL, "should only create Java thread object once"); 1124 1125 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1126 instanceKlassHandle klass (THREAD, k); 1127 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1128 1129 java_lang_Thread::set_thread(thread_oop(), this); 1130 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1131 set_threadObj(thread_oop()); 1132 1133 JavaValue result(T_VOID); 1134 if (thread_name != NULL) { 1135 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1136 // Thread gets assigned specified name and null target 1137 JavaCalls::call_special(&result, 1138 thread_oop, 1139 klass, 1140 vmSymbols::object_initializer_name(), 1141 vmSymbols::threadgroup_string_void_signature(), 1142 thread_group, // Argument 1 1143 name, // Argument 2 1144 THREAD); 1145 } else { 1146 // Thread gets assigned name "Thread-nnn" and null target 1147 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1148 JavaCalls::call_special(&result, 1149 thread_oop, 1150 klass, 1151 vmSymbols::object_initializer_name(), 1152 vmSymbols::threadgroup_runnable_void_signature(), 1153 thread_group, // Argument 1 1154 Handle(), // Argument 2 1155 THREAD); 1156 } 1157 1158 1159 if (daemon) { 1160 java_lang_Thread::set_daemon(thread_oop()); 1161 } 1162 1163 if (HAS_PENDING_EXCEPTION) { 1164 return; 1165 } 1166 1167 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1168 Handle threadObj(this, this->threadObj()); 1169 1170 JavaCalls::call_special(&result, 1171 thread_group, 1172 group, 1173 vmSymbols::add_method_name(), 1174 vmSymbols::thread_void_signature(), 1175 threadObj, // Arg 1 1176 THREAD); 1177 1178 1179 } 1180 1181 // NamedThread -- non-JavaThread subclasses with multiple 1182 // uniquely named instances should derive from this. 1183 NamedThread::NamedThread() : Thread() { 1184 _name = NULL; 1185 _processed_thread = NULL; 1186 } 1187 1188 NamedThread::~NamedThread() { 1189 if (_name != NULL) { 1190 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1191 _name = NULL; 1192 } 1193 } 1194 1195 void NamedThread::set_name(const char* format, ...) { 1196 guarantee(_name == NULL, "Only get to set name once."); 1197 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1198 guarantee(_name != NULL, "alloc failure"); 1199 va_list ap; 1200 va_start(ap, format); 1201 jio_vsnprintf(_name, max_name_len, format, ap); 1202 va_end(ap); 1203 } 1204 1205 void NamedThread::print_on(outputStream* st) const { 1206 st->print("\"%s\" ", name()); 1207 Thread::print_on(st); 1208 st->cr(); 1209 } 1210 1211 1212 // ======= WatcherThread ======== 1213 1214 // The watcher thread exists to simulate timer interrupts. It should 1215 // be replaced by an abstraction over whatever native support for 1216 // timer interrupts exists on the platform. 1217 1218 WatcherThread* WatcherThread::_watcher_thread = NULL; 1219 bool WatcherThread::_startable = false; 1220 volatile bool WatcherThread::_should_terminate = false; 1221 1222 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1223 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1224 if (os::create_thread(this, os::watcher_thread)) { 1225 _watcher_thread = this; 1226 1227 // Set the watcher thread to the highest OS priority which should not be 1228 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1229 // is created. The only normal thread using this priority is the reference 1230 // handler thread, which runs for very short intervals only. 1231 // If the VMThread's priority is not lower than the WatcherThread profiling 1232 // will be inaccurate. 1233 os::set_priority(this, MaxPriority); 1234 if (!DisableStartThread) { 1235 os::start_thread(this); 1236 } 1237 } 1238 } 1239 1240 int WatcherThread::sleep() const { 1241 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1242 1243 // remaining will be zero if there are no tasks, 1244 // causing the WatcherThread to sleep until a task is 1245 // enrolled 1246 int remaining = PeriodicTask::time_to_wait(); 1247 int time_slept = 0; 1248 1249 // we expect this to timeout - we only ever get unparked when 1250 // we should terminate or when a new task has been enrolled 1251 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1252 1253 jlong time_before_loop = os::javaTimeNanos(); 1254 1255 for (;;) { 1256 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1257 jlong now = os::javaTimeNanos(); 1258 1259 if (remaining == 0) { 1260 // if we didn't have any tasks we could have waited for a long time 1261 // consider the time_slept zero and reset time_before_loop 1262 time_slept = 0; 1263 time_before_loop = now; 1264 } else { 1265 // need to recalculate since we might have new tasks in _tasks 1266 time_slept = (int) ((now - time_before_loop) / 1000000); 1267 } 1268 1269 // Change to task list or spurious wakeup of some kind 1270 if (timedout || _should_terminate) { 1271 break; 1272 } 1273 1274 remaining = PeriodicTask::time_to_wait(); 1275 if (remaining == 0) { 1276 // Last task was just disenrolled so loop around and wait until 1277 // another task gets enrolled 1278 continue; 1279 } 1280 1281 remaining -= time_slept; 1282 if (remaining <= 0) 1283 break; 1284 } 1285 1286 return time_slept; 1287 } 1288 1289 void WatcherThread::run() { 1290 assert(this == watcher_thread(), "just checking"); 1291 1292 this->record_stack_base_and_size(); 1293 this->initialize_thread_local_storage(); 1294 this->set_active_handles(JNIHandleBlock::allocate_block()); 1295 while(!_should_terminate) { 1296 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1297 assert(watcher_thread() == this, "thread consistency check"); 1298 1299 // Calculate how long it'll be until the next PeriodicTask work 1300 // should be done, and sleep that amount of time. 1301 int time_waited = sleep(); 1302 1303 if (is_error_reported()) { 1304 // A fatal error has happened, the error handler(VMError::report_and_die) 1305 // should abort JVM after creating an error log file. However in some 1306 // rare cases, the error handler itself might deadlock. Here we try to 1307 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1308 // 1309 // This code is in WatcherThread because WatcherThread wakes up 1310 // periodically so the fatal error handler doesn't need to do anything; 1311 // also because the WatcherThread is less likely to crash than other 1312 // threads. 1313 1314 for (;;) { 1315 if (!ShowMessageBoxOnError 1316 && (OnError == NULL || OnError[0] == '\0') 1317 && Arguments::abort_hook() == NULL) { 1318 os::sleep(this, 2 * 60 * 1000, false); 1319 fdStream err(defaultStream::output_fd()); 1320 err.print_raw_cr("# [ timer expired, abort... ]"); 1321 // skip atexit/vm_exit/vm_abort hooks 1322 os::die(); 1323 } 1324 1325 // Wake up 5 seconds later, the fatal handler may reset OnError or 1326 // ShowMessageBoxOnError when it is ready to abort. 1327 os::sleep(this, 5 * 1000, false); 1328 } 1329 } 1330 1331 PeriodicTask::real_time_tick(time_waited); 1332 } 1333 1334 // Signal that it is terminated 1335 { 1336 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1337 _watcher_thread = NULL; 1338 Terminator_lock->notify(); 1339 } 1340 1341 // Thread destructor usually does this.. 1342 ThreadLocalStorage::set_thread(NULL); 1343 } 1344 1345 void WatcherThread::start() { 1346 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1347 1348 if (watcher_thread() == NULL && _startable) { 1349 _should_terminate = false; 1350 // Create the single instance of WatcherThread 1351 new WatcherThread(); 1352 } 1353 } 1354 1355 void WatcherThread::make_startable() { 1356 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1357 _startable = true; 1358 } 1359 1360 void WatcherThread::stop() { 1361 { 1362 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1363 _should_terminate = true; 1364 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1365 1366 WatcherThread* watcher = watcher_thread(); 1367 if (watcher != NULL) 1368 watcher->unpark(); 1369 } 1370 1371 // it is ok to take late safepoints here, if needed 1372 MutexLocker mu(Terminator_lock); 1373 1374 while(watcher_thread() != NULL) { 1375 // This wait should make safepoint checks, wait without a timeout, 1376 // and wait as a suspend-equivalent condition. 1377 // 1378 // Note: If the FlatProfiler is running, then this thread is waiting 1379 // for the WatcherThread to terminate and the WatcherThread, via the 1380 // FlatProfiler task, is waiting for the external suspend request on 1381 // this thread to complete. wait_for_ext_suspend_completion() will 1382 // eventually timeout, but that takes time. Making this wait a 1383 // suspend-equivalent condition solves that timeout problem. 1384 // 1385 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1386 Mutex::_as_suspend_equivalent_flag); 1387 } 1388 } 1389 1390 void WatcherThread::unpark() { 1391 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1392 PeriodicTask_lock->notify(); 1393 } 1394 1395 void WatcherThread::print_on(outputStream* st) const { 1396 st->print("\"%s\" ", name()); 1397 Thread::print_on(st); 1398 st->cr(); 1399 } 1400 1401 // ======= JavaThread ======== 1402 1403 // A JavaThread is a normal Java thread 1404 1405 void JavaThread::initialize() { 1406 // Initialize fields 1407 1408 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1409 set_claimed_par_id(UINT_MAX); 1410 1411 set_saved_exception_pc(NULL); 1412 set_threadObj(NULL); 1413 _anchor.clear(); 1414 set_entry_point(NULL); 1415 set_jni_functions(jni_functions()); 1416 set_callee_target(NULL); 1417 set_vm_result(NULL); 1418 set_vm_result_2(NULL); 1419 set_vframe_array_head(NULL); 1420 set_vframe_array_last(NULL); 1421 set_deferred_locals(NULL); 1422 set_deopt_mark(NULL); 1423 set_deopt_nmethod(NULL); 1424 clear_must_deopt_id(); 1425 set_monitor_chunks(NULL); 1426 set_next(NULL); 1427 set_thread_state(_thread_new); 1428 #if INCLUDE_NMT 1429 set_recorder(NULL); 1430 #endif 1431 _terminated = _not_terminated; 1432 _privileged_stack_top = NULL; 1433 _array_for_gc = NULL; 1434 _suspend_equivalent = false; 1435 _in_deopt_handler = 0; 1436 _doing_unsafe_access = false; 1437 _stack_guard_state = stack_guard_unused; 1438 (void)const_cast<oop&>(_exception_oop = NULL); 1439 _exception_pc = 0; 1440 _exception_handler_pc = 0; 1441 _is_method_handle_return = 0; 1442 _jvmti_thread_state= NULL; 1443 _should_post_on_exceptions_flag = JNI_FALSE; 1444 _jvmti_get_loaded_classes_closure = NULL; 1445 _interp_only_mode = 0; 1446 _special_runtime_exit_condition = _no_async_condition; 1447 _pending_async_exception = NULL; 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 validity of stack trace backs 1633 this->record_base_of_stack_pointer(); 1634 1635 // Record real stack base and size. 1636 this->record_stack_base_and_size(); 1637 1638 // Initialize thread local storage; set before calling MutexLocker 1639 this->initialize_thread_local_storage(); 1640 1641 this->create_stack_guard_pages(); 1642 1643 this->cache_global_variables(); 1644 1645 // Thread is now sufficient initialized to be handled by the safepoint code as being 1646 // in the VM. Change thread state from _thread_new to _thread_in_vm 1647 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1648 1649 assert(JavaThread::current() == this, "sanity check"); 1650 assert(!Thread::current()->owns_locks(), "sanity check"); 1651 1652 DTRACE_THREAD_PROBE(start, this); 1653 1654 // This operation might block. We call that after all safepoint checks for a new thread has 1655 // been completed. 1656 this->set_active_handles(JNIHandleBlock::allocate_block()); 1657 1658 if (JvmtiExport::should_post_thread_life()) { 1659 JvmtiExport::post_thread_start(this); 1660 } 1661 1662 EventThreadStart event; 1663 if (event.should_commit()) { 1664 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1665 event.commit(); 1666 } 1667 1668 // We call another function to do the rest so we are sure that the stack addresses used 1669 // from there will be lower than the stack base just computed 1670 thread_main_inner(); 1671 1672 // Note, thread is no longer valid at this point! 1673 } 1674 1675 1676 void JavaThread::thread_main_inner() { 1677 assert(JavaThread::current() == this, "sanity check"); 1678 assert(this->threadObj() != NULL, "just checking"); 1679 1680 // Execute thread entry point unless this thread has a pending exception 1681 // or has been stopped before starting. 1682 // Note: Due to JVM_StopThread we can have pending exceptions already! 1683 if (!this->has_pending_exception() && 1684 !java_lang_Thread::is_stillborn(this->threadObj())) { 1685 { 1686 ResourceMark rm(this); 1687 this->set_native_thread_name(this->get_thread_name()); 1688 } 1689 HandleMark hm(this); 1690 this->entry_point()(this, this); 1691 } 1692 1693 DTRACE_THREAD_PROBE(stop, this); 1694 1695 this->exit(false); 1696 delete this; 1697 } 1698 1699 1700 static void ensure_join(JavaThread* thread) { 1701 // We do not need to grap the Threads_lock, since we are operating on ourself. 1702 Handle threadObj(thread, thread->threadObj()); 1703 assert(threadObj.not_null(), "java thread object must exist"); 1704 ObjectLocker lock(threadObj, thread); 1705 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1706 thread->clear_pending_exception(); 1707 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1708 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1709 // Clear the native thread instance - this makes isAlive return false and allows the join() 1710 // to complete once we've done the notify_all below 1711 java_lang_Thread::set_thread(threadObj(), NULL); 1712 lock.notify_all(thread); 1713 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1714 thread->clear_pending_exception(); 1715 } 1716 1717 1718 // For any new cleanup additions, please check to see if they need to be applied to 1719 // cleanup_failed_attach_current_thread as well. 1720 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1721 assert(this == JavaThread::current(), "thread consistency check"); 1722 1723 HandleMark hm(this); 1724 Handle uncaught_exception(this, this->pending_exception()); 1725 this->clear_pending_exception(); 1726 Handle threadObj(this, this->threadObj()); 1727 assert(threadObj.not_null(), "Java thread object should be created"); 1728 1729 if (get_thread_profiler() != NULL) { 1730 get_thread_profiler()->disengage(); 1731 ResourceMark rm; 1732 get_thread_profiler()->print(get_thread_name()); 1733 } 1734 1735 1736 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1737 { 1738 EXCEPTION_MARK; 1739 1740 CLEAR_PENDING_EXCEPTION; 1741 } 1742 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1743 // has to be fixed by a runtime query method 1744 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1745 // JSR-166: change call from from ThreadGroup.uncaughtException to 1746 // java.lang.Thread.dispatchUncaughtException 1747 if (uncaught_exception.not_null()) { 1748 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1749 { 1750 EXCEPTION_MARK; 1751 // Check if the method Thread.dispatchUncaughtException() exists. If so 1752 // call it. Otherwise we have an older library without the JSR-166 changes, 1753 // so call ThreadGroup.uncaughtException() 1754 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1755 CallInfo callinfo; 1756 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1757 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1758 vmSymbols::dispatchUncaughtException_name(), 1759 vmSymbols::throwable_void_signature(), 1760 KlassHandle(), false, false, THREAD); 1761 CLEAR_PENDING_EXCEPTION; 1762 methodHandle method = callinfo.selected_method(); 1763 if (method.not_null()) { 1764 JavaValue result(T_VOID); 1765 JavaCalls::call_virtual(&result, 1766 threadObj, thread_klass, 1767 vmSymbols::dispatchUncaughtException_name(), 1768 vmSymbols::throwable_void_signature(), 1769 uncaught_exception, 1770 THREAD); 1771 } else { 1772 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1773 JavaValue result(T_VOID); 1774 JavaCalls::call_virtual(&result, 1775 group, thread_group, 1776 vmSymbols::uncaughtException_name(), 1777 vmSymbols::thread_throwable_void_signature(), 1778 threadObj, // Arg 1 1779 uncaught_exception, // Arg 2 1780 THREAD); 1781 } 1782 if (HAS_PENDING_EXCEPTION) { 1783 ResourceMark rm(this); 1784 jio_fprintf(defaultStream::error_stream(), 1785 "\nException: %s thrown from the UncaughtExceptionHandler" 1786 " in thread \"%s\"\n", 1787 pending_exception()->klass()->external_name(), 1788 get_thread_name()); 1789 CLEAR_PENDING_EXCEPTION; 1790 } 1791 } 1792 } 1793 1794 // Called before the java thread exit since we want to read info 1795 // from java_lang_Thread object 1796 EventThreadEnd event; 1797 if (event.should_commit()) { 1798 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1799 event.commit(); 1800 } 1801 1802 // Call after last event on thread 1803 EVENT_THREAD_EXIT(this); 1804 1805 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1806 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1807 // is deprecated anyhow. 1808 if (!is_Compiler_thread()) { 1809 int count = 3; 1810 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1811 EXCEPTION_MARK; 1812 JavaValue result(T_VOID); 1813 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1814 JavaCalls::call_virtual(&result, 1815 threadObj, thread_klass, 1816 vmSymbols::exit_method_name(), 1817 vmSymbols::void_method_signature(), 1818 THREAD); 1819 CLEAR_PENDING_EXCEPTION; 1820 } 1821 } 1822 // notify JVMTI 1823 if (JvmtiExport::should_post_thread_life()) { 1824 JvmtiExport::post_thread_end(this); 1825 } 1826 1827 // We have notified the agents that we are exiting, before we go on, 1828 // we must check for a pending external suspend request and honor it 1829 // in order to not surprise the thread that made the suspend request. 1830 while (true) { 1831 { 1832 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1833 if (!is_external_suspend()) { 1834 set_terminated(_thread_exiting); 1835 ThreadService::current_thread_exiting(this); 1836 break; 1837 } 1838 // Implied else: 1839 // Things get a little tricky here. We have a pending external 1840 // suspend request, but we are holding the SR_lock so we 1841 // can't just self-suspend. So we temporarily drop the lock 1842 // and then self-suspend. 1843 } 1844 1845 ThreadBlockInVM tbivm(this); 1846 java_suspend_self(); 1847 1848 // We're done with this suspend request, but we have to loop around 1849 // and check again. Eventually we will get SR_lock without a pending 1850 // external suspend request and will be able to mark ourselves as 1851 // exiting. 1852 } 1853 // no more external suspends are allowed at this point 1854 } else { 1855 // before_exit() has already posted JVMTI THREAD_END events 1856 } 1857 1858 // Notify waiters on thread object. This has to be done after exit() is called 1859 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1860 // group should have the destroyed bit set before waiters are notified). 1861 ensure_join(this); 1862 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1863 1864 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1865 // held by this thread must be released. A detach operation must only 1866 // get here if there are no Java frames on the stack. Therefore, any 1867 // owned monitors at this point MUST be JNI-acquired monitors which are 1868 // pre-inflated and in the monitor cache. 1869 // 1870 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1871 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1872 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1873 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1874 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1875 } 1876 1877 // These things needs to be done while we are still a Java Thread. Make sure that thread 1878 // is in a consistent state, in case GC happens 1879 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1880 1881 if (active_handles() != NULL) { 1882 JNIHandleBlock* block = active_handles(); 1883 set_active_handles(NULL); 1884 JNIHandleBlock::release_block(block); 1885 } 1886 1887 if (free_handle_block() != NULL) { 1888 JNIHandleBlock* block = free_handle_block(); 1889 set_free_handle_block(NULL); 1890 JNIHandleBlock::release_block(block); 1891 } 1892 1893 // These have to be removed while this is still a valid thread. 1894 remove_stack_guard_pages(); 1895 1896 if (UseTLAB) { 1897 tlab().make_parsable(true); // retire TLAB 1898 } 1899 1900 if (JvmtiEnv::environments_might_exist()) { 1901 JvmtiExport::cleanup_thread(this); 1902 } 1903 1904 // We must flush any deferred card marks before removing a thread from 1905 // the list of active threads. 1906 Universe::heap()->flush_deferred_store_barrier(this); 1907 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1908 1909 #if INCLUDE_ALL_GCS 1910 // We must flush the G1-related buffers before removing a thread 1911 // from the list of active threads. We must do this after any deferred 1912 // card marks have been flushed (above) so that any entries that are 1913 // added to the thread's dirty card queue as a result are not lost. 1914 if (UseG1GC) { 1915 flush_barrier_queues(); 1916 } 1917 #endif // INCLUDE_ALL_GCS 1918 1919 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1920 Threads::remove(this); 1921 } 1922 1923 #if INCLUDE_ALL_GCS 1924 // Flush G1-related queues. 1925 void JavaThread::flush_barrier_queues() { 1926 satb_mark_queue().flush(); 1927 dirty_card_queue().flush(); 1928 } 1929 1930 void JavaThread::initialize_queues() { 1931 assert(!SafepointSynchronize::is_at_safepoint(), 1932 "we should not be at a safepoint"); 1933 1934 ObjPtrQueue& satb_queue = satb_mark_queue(); 1935 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1936 // The SATB queue should have been constructed with its active 1937 // field set to false. 1938 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1939 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1940 // If we are creating the thread during a marking cycle, we should 1941 // set the active field of the SATB queue to true. 1942 if (satb_queue_set.is_active()) { 1943 satb_queue.set_active(true); 1944 } 1945 1946 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1947 // The dirty card queue should have been constructed with its 1948 // active field set to true. 1949 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1950 } 1951 #endif // INCLUDE_ALL_GCS 1952 1953 void JavaThread::cleanup_failed_attach_current_thread() { 1954 if (get_thread_profiler() != NULL) { 1955 get_thread_profiler()->disengage(); 1956 ResourceMark rm; 1957 get_thread_profiler()->print(get_thread_name()); 1958 } 1959 1960 if (active_handles() != NULL) { 1961 JNIHandleBlock* block = active_handles(); 1962 set_active_handles(NULL); 1963 JNIHandleBlock::release_block(block); 1964 } 1965 1966 if (free_handle_block() != NULL) { 1967 JNIHandleBlock* block = free_handle_block(); 1968 set_free_handle_block(NULL); 1969 JNIHandleBlock::release_block(block); 1970 } 1971 1972 // These have to be removed while this is still a valid thread. 1973 remove_stack_guard_pages(); 1974 1975 if (UseTLAB) { 1976 tlab().make_parsable(true); // retire TLAB, if any 1977 } 1978 1979 #if INCLUDE_ALL_GCS 1980 if (UseG1GC) { 1981 flush_barrier_queues(); 1982 } 1983 #endif // INCLUDE_ALL_GCS 1984 1985 Threads::remove(this); 1986 delete this; 1987 } 1988 1989 1990 1991 1992 JavaThread* JavaThread::active() { 1993 Thread* thread = ThreadLocalStorage::thread(); 1994 assert(thread != NULL, "just checking"); 1995 if (thread->is_Java_thread()) { 1996 return (JavaThread*) thread; 1997 } else { 1998 assert(thread->is_VM_thread(), "this must be a vm thread"); 1999 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2000 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2001 assert(ret->is_Java_thread(), "must be a Java thread"); 2002 return ret; 2003 } 2004 } 2005 2006 bool JavaThread::is_lock_owned(address adr) const { 2007 if (Thread::is_lock_owned(adr)) return true; 2008 2009 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2010 if (chunk->contains(adr)) return true; 2011 } 2012 2013 return false; 2014 } 2015 2016 2017 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2018 chunk->set_next(monitor_chunks()); 2019 set_monitor_chunks(chunk); 2020 } 2021 2022 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2023 guarantee(monitor_chunks() != NULL, "must be non empty"); 2024 if (monitor_chunks() == chunk) { 2025 set_monitor_chunks(chunk->next()); 2026 } else { 2027 MonitorChunk* prev = monitor_chunks(); 2028 while (prev->next() != chunk) prev = prev->next(); 2029 prev->set_next(chunk->next()); 2030 } 2031 } 2032 2033 // JVM support. 2034 2035 // Note: this function shouldn't block if it's called in 2036 // _thread_in_native_trans state (such as from 2037 // check_special_condition_for_native_trans()). 2038 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2039 2040 if (has_last_Java_frame() && has_async_condition()) { 2041 // If we are at a polling page safepoint (not a poll return) 2042 // then we must defer async exception because live registers 2043 // will be clobbered by the exception path. Poll return is 2044 // ok because the call we a returning from already collides 2045 // with exception handling registers and so there is no issue. 2046 // (The exception handling path kills call result registers but 2047 // this is ok since the exception kills the result anyway). 2048 2049 if (is_at_poll_safepoint()) { 2050 // if the code we are returning to has deoptimized we must defer 2051 // the exception otherwise live registers get clobbered on the 2052 // exception path before deoptimization is able to retrieve them. 2053 // 2054 RegisterMap map(this, false); 2055 frame caller_fr = last_frame().sender(&map); 2056 assert(caller_fr.is_compiled_frame(), "what?"); 2057 if (caller_fr.is_deoptimized_frame()) { 2058 if (TraceExceptions) { 2059 ResourceMark rm; 2060 tty->print_cr("deferred async exception at compiled safepoint"); 2061 } 2062 return; 2063 } 2064 } 2065 } 2066 2067 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2068 if (condition == _no_async_condition) { 2069 // Conditions have changed since has_special_runtime_exit_condition() 2070 // was called: 2071 // - if we were here only because of an external suspend request, 2072 // then that was taken care of above (or cancelled) so we are done 2073 // - if we were here because of another async request, then it has 2074 // been cleared between the has_special_runtime_exit_condition() 2075 // and now so again we are done 2076 return; 2077 } 2078 2079 // Check for pending async. exception 2080 if (_pending_async_exception != NULL) { 2081 // Only overwrite an already pending exception, if it is not a threadDeath. 2082 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2083 2084 // We cannot call Exceptions::_throw(...) here because we cannot block 2085 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2086 2087 if (TraceExceptions) { 2088 ResourceMark rm; 2089 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2090 if (has_last_Java_frame() ) { 2091 frame f = last_frame(); 2092 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2093 } 2094 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2095 } 2096 _pending_async_exception = NULL; 2097 clear_has_async_exception(); 2098 } 2099 } 2100 2101 if (check_unsafe_error && 2102 condition == _async_unsafe_access_error && !has_pending_exception()) { 2103 condition = _no_async_condition; // done 2104 switch (thread_state()) { 2105 case _thread_in_vm: 2106 { 2107 JavaThread* THREAD = this; 2108 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2109 } 2110 case _thread_in_native: 2111 { 2112 ThreadInVMfromNative tiv(this); 2113 JavaThread* THREAD = this; 2114 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2115 } 2116 case _thread_in_Java: 2117 { 2118 ThreadInVMfromJava tiv(this); 2119 JavaThread* THREAD = this; 2120 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2121 } 2122 default: 2123 ShouldNotReachHere(); 2124 } 2125 } 2126 2127 assert(condition == _no_async_condition || has_pending_exception() || 2128 (!check_unsafe_error && condition == _async_unsafe_access_error), 2129 "must have handled the async condition, if no exception"); 2130 } 2131 2132 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2133 // 2134 // Check for pending external suspend. Internal suspend requests do 2135 // not use handle_special_runtime_exit_condition(). 2136 // If JNIEnv proxies are allowed, don't self-suspend if the target 2137 // thread is not the current thread. In older versions of jdbx, jdbx 2138 // threads could call into the VM with another thread's JNIEnv so we 2139 // can be here operating on behalf of a suspended thread (4432884). 2140 bool do_self_suspend = is_external_suspend_with_lock(); 2141 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2142 // 2143 // Because thread is external suspended the safepoint code will count 2144 // thread as at a safepoint. This can be odd because we can be here 2145 // as _thread_in_Java which would normally transition to _thread_blocked 2146 // at a safepoint. We would like to mark the thread as _thread_blocked 2147 // before calling java_suspend_self like all other callers of it but 2148 // we must then observe proper safepoint protocol. (We can't leave 2149 // _thread_blocked with a safepoint in progress). However we can be 2150 // here as _thread_in_native_trans so we can't use a normal transition 2151 // constructor/destructor pair because they assert on that type of 2152 // transition. We could do something like: 2153 // 2154 // JavaThreadState state = thread_state(); 2155 // set_thread_state(_thread_in_vm); 2156 // { 2157 // ThreadBlockInVM tbivm(this); 2158 // java_suspend_self() 2159 // } 2160 // set_thread_state(_thread_in_vm_trans); 2161 // if (safepoint) block; 2162 // set_thread_state(state); 2163 // 2164 // but that is pretty messy. Instead we just go with the way the 2165 // code has worked before and note that this is the only path to 2166 // java_suspend_self that doesn't put the thread in _thread_blocked 2167 // mode. 2168 2169 frame_anchor()->make_walkable(this); 2170 java_suspend_self(); 2171 2172 // We might be here for reasons in addition to the self-suspend request 2173 // so check for other async requests. 2174 } 2175 2176 if (check_asyncs) { 2177 check_and_handle_async_exceptions(); 2178 } 2179 } 2180 2181 void JavaThread::send_thread_stop(oop java_throwable) { 2182 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2183 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2184 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2185 2186 // Do not throw asynchronous exceptions against the compiler thread 2187 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2188 if (is_Compiler_thread()) return; 2189 2190 { 2191 // Actually throw the Throwable against the target Thread - however 2192 // only if there is no thread death exception installed already. 2193 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2194 // If the topmost frame is a runtime stub, then we are calling into 2195 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2196 // must deoptimize the caller before continuing, as the compiled exception handler table 2197 // may not be valid 2198 if (has_last_Java_frame()) { 2199 frame f = last_frame(); 2200 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2201 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2202 RegisterMap reg_map(this, UseBiasedLocking); 2203 frame compiled_frame = f.sender(®_map); 2204 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2205 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2206 } 2207 } 2208 } 2209 2210 // Set async. pending exception in thread. 2211 set_pending_async_exception(java_throwable); 2212 2213 if (TraceExceptions) { 2214 ResourceMark rm; 2215 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2216 } 2217 // for AbortVMOnException flag 2218 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2219 } 2220 } 2221 2222 2223 // Interrupt thread so it will wake up from a potential wait() 2224 Thread::interrupt(this); 2225 } 2226 2227 // External suspension mechanism. 2228 // 2229 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2230 // to any VM_locks and it is at a transition 2231 // Self-suspension will happen on the transition out of the vm. 2232 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2233 // 2234 // Guarantees on return: 2235 // + Target thread will not execute any new bytecode (that's why we need to 2236 // force a safepoint) 2237 // + Target thread will not enter any new monitors 2238 // 2239 void JavaThread::java_suspend() { 2240 { MutexLocker mu(Threads_lock); 2241 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2242 return; 2243 } 2244 } 2245 2246 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2247 if (!is_external_suspend()) { 2248 // a racing resume has cancelled us; bail out now 2249 return; 2250 } 2251 2252 // suspend is done 2253 uint32_t debug_bits = 0; 2254 // Warning: is_ext_suspend_completed() may temporarily drop the 2255 // SR_lock to allow the thread to reach a stable thread state if 2256 // it is currently in a transient thread state. 2257 if (is_ext_suspend_completed(false /* !called_by_wait */, 2258 SuspendRetryDelay, &debug_bits) ) { 2259 return; 2260 } 2261 } 2262 2263 VM_ForceSafepoint vm_suspend; 2264 VMThread::execute(&vm_suspend); 2265 } 2266 2267 // Part II of external suspension. 2268 // A JavaThread self suspends when it detects a pending external suspend 2269 // request. This is usually on transitions. It is also done in places 2270 // where continuing to the next transition would surprise the caller, 2271 // e.g., monitor entry. 2272 // 2273 // Returns the number of times that the thread self-suspended. 2274 // 2275 // Note: DO NOT call java_suspend_self() when you just want to block current 2276 // thread. java_suspend_self() is the second stage of cooperative 2277 // suspension for external suspend requests and should only be used 2278 // to complete an external suspend request. 2279 // 2280 int JavaThread::java_suspend_self() { 2281 int ret = 0; 2282 2283 // we are in the process of exiting so don't suspend 2284 if (is_exiting()) { 2285 clear_external_suspend(); 2286 return ret; 2287 } 2288 2289 assert(_anchor.walkable() || 2290 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2291 "must have walkable stack"); 2292 2293 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2294 2295 assert(!this->is_ext_suspended(), 2296 "a thread trying to self-suspend should not already be suspended"); 2297 2298 if (this->is_suspend_equivalent()) { 2299 // If we are self-suspending as a result of the lifting of a 2300 // suspend equivalent condition, then the suspend_equivalent 2301 // flag is not cleared until we set the ext_suspended flag so 2302 // that wait_for_ext_suspend_completion() returns consistent 2303 // results. 2304 this->clear_suspend_equivalent(); 2305 } 2306 2307 // A racing resume may have cancelled us before we grabbed SR_lock 2308 // above. Or another external suspend request could be waiting for us 2309 // by the time we return from SR_lock()->wait(). The thread 2310 // that requested the suspension may already be trying to walk our 2311 // stack and if we return now, we can change the stack out from under 2312 // it. This would be a "bad thing (TM)" and cause the stack walker 2313 // to crash. We stay self-suspended until there are no more pending 2314 // external suspend requests. 2315 while (is_external_suspend()) { 2316 ret++; 2317 this->set_ext_suspended(); 2318 2319 // _ext_suspended flag is cleared by java_resume() 2320 while (is_ext_suspended()) { 2321 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2322 } 2323 } 2324 2325 return ret; 2326 } 2327 2328 #ifdef ASSERT 2329 // verify the JavaThread has not yet been published in the Threads::list, and 2330 // hence doesn't need protection from concurrent access at this stage 2331 void JavaThread::verify_not_published() { 2332 if (!Threads_lock->owned_by_self()) { 2333 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2334 assert( !Threads::includes(this), 2335 "java thread shouldn't have been published yet!"); 2336 } 2337 else { 2338 assert( !Threads::includes(this), 2339 "java thread shouldn't have been published yet!"); 2340 } 2341 } 2342 #endif 2343 2344 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2345 // progress or when _suspend_flags is non-zero. 2346 // Current thread needs to self-suspend if there is a suspend request and/or 2347 // block if a safepoint is in progress. 2348 // Async exception ISN'T checked. 2349 // Note only the ThreadInVMfromNative transition can call this function 2350 // directly and when thread state is _thread_in_native_trans 2351 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2352 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2353 2354 JavaThread *curJT = JavaThread::current(); 2355 bool do_self_suspend = thread->is_external_suspend(); 2356 2357 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2358 2359 // If JNIEnv proxies are allowed, don't self-suspend if the target 2360 // thread is not the current thread. In older versions of jdbx, jdbx 2361 // threads could call into the VM with another thread's JNIEnv so we 2362 // can be here operating on behalf of a suspended thread (4432884). 2363 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2364 JavaThreadState state = thread->thread_state(); 2365 2366 // We mark this thread_blocked state as a suspend-equivalent so 2367 // that a caller to is_ext_suspend_completed() won't be confused. 2368 // The suspend-equivalent state is cleared by java_suspend_self(). 2369 thread->set_suspend_equivalent(); 2370 2371 // If the safepoint code sees the _thread_in_native_trans state, it will 2372 // wait until the thread changes to other thread state. There is no 2373 // guarantee on how soon we can obtain the SR_lock and complete the 2374 // self-suspend request. It would be a bad idea to let safepoint wait for 2375 // too long. Temporarily change the state to _thread_blocked to 2376 // let the VM thread know that this thread is ready for GC. The problem 2377 // of changing thread state is that safepoint could happen just after 2378 // java_suspend_self() returns after being resumed, and VM thread will 2379 // see the _thread_blocked state. We must check for safepoint 2380 // after restoring the state and make sure we won't leave while a safepoint 2381 // is in progress. 2382 thread->set_thread_state(_thread_blocked); 2383 thread->java_suspend_self(); 2384 thread->set_thread_state(state); 2385 // Make sure new state is seen by VM thread 2386 if (os::is_MP()) { 2387 if (UseMembar) { 2388 // Force a fence between the write above and read below 2389 OrderAccess::fence(); 2390 } else { 2391 // Must use this rather than serialization page in particular on Windows 2392 InterfaceSupport::serialize_memory(thread); 2393 } 2394 } 2395 } 2396 2397 if (SafepointSynchronize::do_call_back()) { 2398 // If we are safepointing, then block the caller which may not be 2399 // the same as the target thread (see above). 2400 SafepointSynchronize::block(curJT); 2401 } 2402 2403 if (thread->is_deopt_suspend()) { 2404 thread->clear_deopt_suspend(); 2405 RegisterMap map(thread, false); 2406 frame f = thread->last_frame(); 2407 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2408 f = f.sender(&map); 2409 } 2410 if (f.id() == thread->must_deopt_id()) { 2411 thread->clear_must_deopt_id(); 2412 f.deoptimize(thread); 2413 } else { 2414 fatal("missed deoptimization!"); 2415 } 2416 } 2417 } 2418 2419 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2420 // progress or when _suspend_flags is non-zero. 2421 // Current thread needs to self-suspend if there is a suspend request and/or 2422 // block if a safepoint is in progress. 2423 // Also check for pending async exception (not including unsafe access error). 2424 // Note only the native==>VM/Java barriers can call this function and when 2425 // thread state is _thread_in_native_trans. 2426 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2427 check_safepoint_and_suspend_for_native_trans(thread); 2428 2429 if (thread->has_async_exception()) { 2430 // We are in _thread_in_native_trans state, don't handle unsafe 2431 // access error since that may block. 2432 thread->check_and_handle_async_exceptions(false); 2433 } 2434 } 2435 2436 // This is a variant of the normal 2437 // check_special_condition_for_native_trans with slightly different 2438 // semantics for use by critical native wrappers. It does all the 2439 // normal checks but also performs the transition back into 2440 // thread_in_Java state. This is required so that critical natives 2441 // can potentially block and perform a GC if they are the last thread 2442 // exiting the GC_locker. 2443 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2444 check_special_condition_for_native_trans(thread); 2445 2446 // Finish the transition 2447 thread->set_thread_state(_thread_in_Java); 2448 2449 if (thread->do_critical_native_unlock()) { 2450 ThreadInVMfromJavaNoAsyncException tiv(thread); 2451 GC_locker::unlock_critical(thread); 2452 thread->clear_critical_native_unlock(); 2453 } 2454 } 2455 2456 // We need to guarantee the Threads_lock here, since resumes are not 2457 // allowed during safepoint synchronization 2458 // Can only resume from an external suspension 2459 void JavaThread::java_resume() { 2460 assert_locked_or_safepoint(Threads_lock); 2461 2462 // Sanity check: thread is gone, has started exiting or the thread 2463 // was not externally suspended. 2464 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2465 return; 2466 } 2467 2468 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2469 2470 clear_external_suspend(); 2471 2472 if (is_ext_suspended()) { 2473 clear_ext_suspended(); 2474 SR_lock()->notify_all(); 2475 } 2476 } 2477 2478 void JavaThread::create_stack_guard_pages() { 2479 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2480 address low_addr = stack_base() - stack_size(); 2481 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2482 2483 int allocate = os::allocate_stack_guard_pages(); 2484 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2485 2486 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2487 warning("Attempt to allocate stack guard pages failed."); 2488 return; 2489 } 2490 2491 if (os::guard_memory((char *) low_addr, len)) { 2492 _stack_guard_state = stack_guard_enabled; 2493 } else { 2494 warning("Attempt to protect stack guard pages failed."); 2495 if (os::uncommit_memory((char *) low_addr, len)) { 2496 warning("Attempt to deallocate stack guard pages failed."); 2497 } 2498 } 2499 } 2500 2501 void JavaThread::remove_stack_guard_pages() { 2502 assert(Thread::current() == this, "from different thread"); 2503 if (_stack_guard_state == stack_guard_unused) return; 2504 address low_addr = stack_base() - stack_size(); 2505 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2506 2507 if (os::allocate_stack_guard_pages()) { 2508 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2509 _stack_guard_state = stack_guard_unused; 2510 } else { 2511 warning("Attempt to deallocate stack guard pages failed."); 2512 } 2513 } else { 2514 if (_stack_guard_state == stack_guard_unused) return; 2515 if (os::unguard_memory((char *) low_addr, len)) { 2516 _stack_guard_state = stack_guard_unused; 2517 } else { 2518 warning("Attempt to unprotect stack guard pages failed."); 2519 } 2520 } 2521 } 2522 2523 void JavaThread::enable_stack_yellow_zone() { 2524 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2525 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2526 2527 // The base notation is from the stacks point of view, growing downward. 2528 // We need to adjust it to work correctly with guard_memory() 2529 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2530 2531 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2532 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2533 2534 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2535 _stack_guard_state = stack_guard_enabled; 2536 } else { 2537 warning("Attempt to guard stack yellow zone failed."); 2538 } 2539 enable_register_stack_guard(); 2540 } 2541 2542 void JavaThread::disable_stack_yellow_zone() { 2543 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2544 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2545 2546 // Simply return if called for a thread that does not use guard pages. 2547 if (_stack_guard_state == stack_guard_unused) return; 2548 2549 // The base notation is from the stacks point of view, growing downward. 2550 // We need to adjust it to work correctly with guard_memory() 2551 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2552 2553 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2554 _stack_guard_state = stack_guard_yellow_disabled; 2555 } else { 2556 warning("Attempt to unguard stack yellow zone failed."); 2557 } 2558 disable_register_stack_guard(); 2559 } 2560 2561 void JavaThread::enable_stack_red_zone() { 2562 // The base notation is from the stacks point of view, growing downward. 2563 // We need to adjust it to work correctly with guard_memory() 2564 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2565 address base = stack_red_zone_base() - stack_red_zone_size(); 2566 2567 guarantee(base < stack_base(),"Error calculating stack red zone"); 2568 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2569 2570 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2571 warning("Attempt to guard stack red zone failed."); 2572 } 2573 } 2574 2575 void JavaThread::disable_stack_red_zone() { 2576 // The base notation is from the stacks point of view, growing downward. 2577 // We need to adjust it to work correctly with guard_memory() 2578 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2579 address base = stack_red_zone_base() - stack_red_zone_size(); 2580 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2581 warning("Attempt to unguard stack red zone failed."); 2582 } 2583 } 2584 2585 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2586 // ignore is there is no stack 2587 if (!has_last_Java_frame()) return; 2588 // traverse the stack frames. Starts from top frame. 2589 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2590 frame* fr = fst.current(); 2591 f(fr, fst.register_map()); 2592 } 2593 } 2594 2595 2596 #ifndef PRODUCT 2597 // Deoptimization 2598 // Function for testing deoptimization 2599 void JavaThread::deoptimize() { 2600 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2601 StackFrameStream fst(this, UseBiasedLocking); 2602 bool deopt = false; // Dump stack only if a deopt actually happens. 2603 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2604 // Iterate over all frames in the thread and deoptimize 2605 for(; !fst.is_done(); fst.next()) { 2606 if(fst.current()->can_be_deoptimized()) { 2607 2608 if (only_at) { 2609 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2610 // consists of comma or carriage return separated numbers so 2611 // search for the current bci in that string. 2612 address pc = fst.current()->pc(); 2613 nmethod* nm = (nmethod*) fst.current()->cb(); 2614 ScopeDesc* sd = nm->scope_desc_at( pc); 2615 char buffer[8]; 2616 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2617 size_t len = strlen(buffer); 2618 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2619 while (found != NULL) { 2620 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2621 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2622 // Check that the bci found is bracketed by terminators. 2623 break; 2624 } 2625 found = strstr(found + 1, buffer); 2626 } 2627 if (!found) { 2628 continue; 2629 } 2630 } 2631 2632 if (DebugDeoptimization && !deopt) { 2633 deopt = true; // One-time only print before deopt 2634 tty->print_cr("[BEFORE Deoptimization]"); 2635 trace_frames(); 2636 trace_stack(); 2637 } 2638 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2639 } 2640 } 2641 2642 if (DebugDeoptimization && deopt) { 2643 tty->print_cr("[AFTER Deoptimization]"); 2644 trace_frames(); 2645 } 2646 } 2647 2648 2649 // Make zombies 2650 void JavaThread::make_zombies() { 2651 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2652 if (fst.current()->can_be_deoptimized()) { 2653 // it is a Java nmethod 2654 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2655 nm->make_not_entrant(); 2656 } 2657 } 2658 } 2659 #endif // PRODUCT 2660 2661 2662 void JavaThread::deoptimized_wrt_marked_nmethods() { 2663 if (!has_last_Java_frame()) return; 2664 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2665 StackFrameStream fst(this, UseBiasedLocking); 2666 for(; !fst.is_done(); fst.next()) { 2667 if (fst.current()->should_be_deoptimized()) { 2668 if (LogCompilation && xtty != NULL) { 2669 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2670 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2671 this->name(), nm != NULL ? nm->compile_id() : -1); 2672 } 2673 2674 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2675 } 2676 } 2677 } 2678 2679 2680 // GC support 2681 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2682 2683 void JavaThread::gc_epilogue() { 2684 frames_do(frame_gc_epilogue); 2685 } 2686 2687 2688 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2689 2690 void JavaThread::gc_prologue() { 2691 frames_do(frame_gc_prologue); 2692 } 2693 2694 // If the caller is a NamedThread, then remember, in the current scope, 2695 // the given JavaThread in its _processed_thread field. 2696 class RememberProcessedThread: public StackObj { 2697 NamedThread* _cur_thr; 2698 public: 2699 RememberProcessedThread(JavaThread* jthr) { 2700 Thread* thread = Thread::current(); 2701 if (thread->is_Named_thread()) { 2702 _cur_thr = (NamedThread *)thread; 2703 _cur_thr->set_processed_thread(jthr); 2704 } else { 2705 _cur_thr = NULL; 2706 } 2707 } 2708 2709 ~RememberProcessedThread() { 2710 if (_cur_thr) { 2711 _cur_thr->set_processed_thread(NULL); 2712 } 2713 } 2714 }; 2715 2716 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2717 // Verify that the deferred card marks have been flushed. 2718 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2719 2720 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2721 // since there may be more than one thread using each ThreadProfiler. 2722 2723 // Traverse the GCHandles 2724 Thread::oops_do(f, cld_f, cf); 2725 2726 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2727 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2728 2729 if (has_last_Java_frame()) { 2730 // Record JavaThread to GC thread 2731 RememberProcessedThread rpt(this); 2732 2733 // Traverse the privileged stack 2734 if (_privileged_stack_top != NULL) { 2735 _privileged_stack_top->oops_do(f); 2736 } 2737 2738 // traverse the registered growable array 2739 if (_array_for_gc != NULL) { 2740 for (int index = 0; index < _array_for_gc->length(); index++) { 2741 f->do_oop(_array_for_gc->adr_at(index)); 2742 } 2743 } 2744 2745 // Traverse the monitor chunks 2746 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2747 chunk->oops_do(f); 2748 } 2749 2750 // Traverse the execution stack 2751 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2752 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2753 } 2754 } 2755 2756 // callee_target is never live across a gc point so NULL it here should 2757 // it still contain a methdOop. 2758 2759 set_callee_target(NULL); 2760 2761 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2762 // If we have deferred set_locals there might be oops waiting to be 2763 // written 2764 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2765 if (list != NULL) { 2766 for (int i = 0; i < list->length(); i++) { 2767 list->at(i)->oops_do(f); 2768 } 2769 } 2770 2771 // Traverse instance variables at the end since the GC may be moving things 2772 // around using this function 2773 f->do_oop((oop*) &_threadObj); 2774 f->do_oop((oop*) &_vm_result); 2775 f->do_oop((oop*) &_exception_oop); 2776 f->do_oop((oop*) &_pending_async_exception); 2777 2778 if (jvmti_thread_state() != NULL) { 2779 jvmti_thread_state()->oops_do(f); 2780 } 2781 } 2782 2783 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2784 Thread::nmethods_do(cf); // (super method is a no-op) 2785 2786 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2787 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2788 2789 if (has_last_Java_frame()) { 2790 // Traverse the execution stack 2791 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2792 fst.current()->nmethods_do(cf); 2793 } 2794 } 2795 } 2796 2797 void JavaThread::metadata_do(void f(Metadata*)) { 2798 Thread::metadata_do(f); 2799 if (has_last_Java_frame()) { 2800 // Traverse the execution stack to call f() on the methods in the stack 2801 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2802 fst.current()->metadata_do(f); 2803 } 2804 } else if (is_Compiler_thread()) { 2805 // need to walk ciMetadata in current compile tasks to keep alive. 2806 CompilerThread* ct = (CompilerThread*)this; 2807 if (ct->env() != NULL) { 2808 ct->env()->metadata_do(f); 2809 } 2810 } 2811 } 2812 2813 // Printing 2814 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2815 switch (_thread_state) { 2816 case _thread_uninitialized: return "_thread_uninitialized"; 2817 case _thread_new: return "_thread_new"; 2818 case _thread_new_trans: return "_thread_new_trans"; 2819 case _thread_in_native: return "_thread_in_native"; 2820 case _thread_in_native_trans: return "_thread_in_native_trans"; 2821 case _thread_in_vm: return "_thread_in_vm"; 2822 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2823 case _thread_in_Java: return "_thread_in_Java"; 2824 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2825 case _thread_blocked: return "_thread_blocked"; 2826 case _thread_blocked_trans: return "_thread_blocked_trans"; 2827 default: return "unknown thread state"; 2828 } 2829 } 2830 2831 #ifndef PRODUCT 2832 void JavaThread::print_thread_state_on(outputStream *st) const { 2833 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2834 }; 2835 void JavaThread::print_thread_state() const { 2836 print_thread_state_on(tty); 2837 }; 2838 #endif // PRODUCT 2839 2840 // Called by Threads::print() for VM_PrintThreads operation 2841 void JavaThread::print_on(outputStream *st) const { 2842 st->print("\"%s\" ", get_thread_name()); 2843 oop thread_oop = threadObj(); 2844 if (thread_oop != NULL) { 2845 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2846 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2847 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2848 } 2849 Thread::print_on(st); 2850 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2851 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2852 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2853 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2854 } 2855 #ifndef PRODUCT 2856 print_thread_state_on(st); 2857 _safepoint_state->print_on(st); 2858 #endif // PRODUCT 2859 } 2860 2861 // Called by fatal error handler. The difference between this and 2862 // JavaThread::print() is that we can't grab lock or allocate memory. 2863 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2864 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2865 oop thread_obj = threadObj(); 2866 if (thread_obj != NULL) { 2867 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2868 } 2869 st->print(" ["); 2870 st->print("%s", _get_thread_state_name(_thread_state)); 2871 if (osthread()) { 2872 st->print(", id=%d", osthread()->thread_id()); 2873 } 2874 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2875 _stack_base - _stack_size, _stack_base); 2876 st->print("]"); 2877 return; 2878 } 2879 2880 // Verification 2881 2882 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2883 2884 void JavaThread::verify() { 2885 // Verify oops in the thread. 2886 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2887 2888 // Verify the stack frames. 2889 frames_do(frame_verify); 2890 } 2891 2892 // CR 6300358 (sub-CR 2137150) 2893 // Most callers of this method assume that it can't return NULL but a 2894 // thread may not have a name whilst it is in the process of attaching to 2895 // the VM - see CR 6412693, and there are places where a JavaThread can be 2896 // seen prior to having it's threadObj set (eg JNI attaching threads and 2897 // if vm exit occurs during initialization). These cases can all be accounted 2898 // for such that this method never returns NULL. 2899 const char* JavaThread::get_thread_name() const { 2900 #ifdef ASSERT 2901 // early safepoints can hit while current thread does not yet have TLS 2902 if (!SafepointSynchronize::is_at_safepoint()) { 2903 Thread *cur = Thread::current(); 2904 if (!(cur->is_Java_thread() && cur == this)) { 2905 // Current JavaThreads are allowed to get their own name without 2906 // the Threads_lock. 2907 assert_locked_or_safepoint(Threads_lock); 2908 } 2909 } 2910 #endif // ASSERT 2911 return get_thread_name_string(); 2912 } 2913 2914 // Returns a non-NULL representation of this thread's name, or a suitable 2915 // descriptive string if there is no set name 2916 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2917 const char* name_str; 2918 oop thread_obj = threadObj(); 2919 if (thread_obj != NULL) { 2920 typeArrayOop name = java_lang_Thread::name(thread_obj); 2921 if (name != NULL) { 2922 if (buf == NULL) { 2923 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2924 } 2925 else { 2926 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2927 } 2928 } 2929 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2930 name_str = "<no-name - thread is attaching>"; 2931 } 2932 else { 2933 name_str = Thread::name(); 2934 } 2935 } 2936 else { 2937 name_str = Thread::name(); 2938 } 2939 assert(name_str != NULL, "unexpected NULL thread name"); 2940 return name_str; 2941 } 2942 2943 2944 const char* JavaThread::get_threadgroup_name() const { 2945 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2946 oop thread_obj = threadObj(); 2947 if (thread_obj != NULL) { 2948 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2949 if (thread_group != NULL) { 2950 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2951 // ThreadGroup.name can be null 2952 if (name != NULL) { 2953 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2954 return str; 2955 } 2956 } 2957 } 2958 return NULL; 2959 } 2960 2961 const char* JavaThread::get_parent_name() const { 2962 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2963 oop thread_obj = threadObj(); 2964 if (thread_obj != NULL) { 2965 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2966 if (thread_group != NULL) { 2967 oop parent = java_lang_ThreadGroup::parent(thread_group); 2968 if (parent != NULL) { 2969 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2970 // ThreadGroup.name can be null 2971 if (name != NULL) { 2972 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2973 return str; 2974 } 2975 } 2976 } 2977 } 2978 return NULL; 2979 } 2980 2981 ThreadPriority JavaThread::java_priority() const { 2982 oop thr_oop = threadObj(); 2983 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2984 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2985 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2986 return priority; 2987 } 2988 2989 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2990 2991 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2992 // Link Java Thread object <-> C++ Thread 2993 2994 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2995 // and put it into a new Handle. The Handle "thread_oop" can then 2996 // be used to pass the C++ thread object to other methods. 2997 2998 // Set the Java level thread object (jthread) field of the 2999 // new thread (a JavaThread *) to C++ thread object using the 3000 // "thread_oop" handle. 3001 3002 // Set the thread field (a JavaThread *) of the 3003 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3004 3005 Handle thread_oop(Thread::current(), 3006 JNIHandles::resolve_non_null(jni_thread)); 3007 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3008 "must be initialized"); 3009 set_threadObj(thread_oop()); 3010 java_lang_Thread::set_thread(thread_oop(), this); 3011 3012 if (prio == NoPriority) { 3013 prio = java_lang_Thread::priority(thread_oop()); 3014 assert(prio != NoPriority, "A valid priority should be present"); 3015 } 3016 3017 // Push the Java priority down to the native thread; needs Threads_lock 3018 Thread::set_priority(this, prio); 3019 3020 // Add the new thread to the Threads list and set it in motion. 3021 // We must have threads lock in order to call Threads::add. 3022 // It is crucial that we do not block before the thread is 3023 // added to the Threads list for if a GC happens, then the java_thread oop 3024 // will not be visited by GC. 3025 Threads::add(this); 3026 } 3027 3028 oop JavaThread::current_park_blocker() { 3029 // Support for JSR-166 locks 3030 oop thread_oop = threadObj(); 3031 if (thread_oop != NULL && 3032 JDK_Version::current().supports_thread_park_blocker()) { 3033 return java_lang_Thread::park_blocker(thread_oop); 3034 } 3035 return NULL; 3036 } 3037 3038 3039 void JavaThread::print_stack_on(outputStream* st) { 3040 if (!has_last_Java_frame()) return; 3041 ResourceMark rm; 3042 HandleMark hm; 3043 3044 RegisterMap reg_map(this); 3045 vframe* start_vf = last_java_vframe(®_map); 3046 int count = 0; 3047 for (vframe* f = start_vf; f; f = f->sender() ) { 3048 if (f->is_java_frame()) { 3049 javaVFrame* jvf = javaVFrame::cast(f); 3050 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3051 3052 // Print out lock information 3053 if (JavaMonitorsInStackTrace) { 3054 jvf->print_lock_info_on(st, count); 3055 } 3056 } else { 3057 // Ignore non-Java frames 3058 } 3059 3060 // Bail-out case for too deep stacks 3061 count++; 3062 if (MaxJavaStackTraceDepth == count) return; 3063 } 3064 } 3065 3066 3067 // JVMTI PopFrame support 3068 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3069 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3070 if (in_bytes(size_in_bytes) != 0) { 3071 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3072 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3073 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3074 } 3075 } 3076 3077 void* JavaThread::popframe_preserved_args() { 3078 return _popframe_preserved_args; 3079 } 3080 3081 ByteSize JavaThread::popframe_preserved_args_size() { 3082 return in_ByteSize(_popframe_preserved_args_size); 3083 } 3084 3085 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3086 int sz = in_bytes(popframe_preserved_args_size()); 3087 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3088 return in_WordSize(sz / wordSize); 3089 } 3090 3091 void JavaThread::popframe_free_preserved_args() { 3092 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3093 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3094 _popframe_preserved_args = NULL; 3095 _popframe_preserved_args_size = 0; 3096 } 3097 3098 #ifndef PRODUCT 3099 3100 void JavaThread::trace_frames() { 3101 tty->print_cr("[Describe stack]"); 3102 int frame_no = 1; 3103 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3104 tty->print(" %d. ", frame_no++); 3105 fst.current()->print_value_on(tty,this); 3106 tty->cr(); 3107 } 3108 } 3109 3110 class PrintAndVerifyOopClosure: public OopClosure { 3111 protected: 3112 template <class T> inline void do_oop_work(T* p) { 3113 oop obj = oopDesc::load_decode_heap_oop(p); 3114 if (obj == NULL) return; 3115 tty->print(INTPTR_FORMAT ": ", p); 3116 if (obj->is_oop_or_null()) { 3117 if (obj->is_objArray()) { 3118 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3119 } else { 3120 obj->print(); 3121 } 3122 } else { 3123 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3124 } 3125 tty->cr(); 3126 } 3127 public: 3128 virtual void do_oop(oop* p) { do_oop_work(p); } 3129 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3130 }; 3131 3132 3133 static void oops_print(frame* f, const RegisterMap *map) { 3134 PrintAndVerifyOopClosure print; 3135 f->print_value(); 3136 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3137 } 3138 3139 // Print our all the locations that contain oops and whether they are 3140 // valid or not. This useful when trying to find the oldest frame 3141 // where an oop has gone bad since the frame walk is from youngest to 3142 // oldest. 3143 void JavaThread::trace_oops() { 3144 tty->print_cr("[Trace oops]"); 3145 frames_do(oops_print); 3146 } 3147 3148 3149 #ifdef ASSERT 3150 // Print or validate the layout of stack frames 3151 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3152 ResourceMark rm; 3153 PRESERVE_EXCEPTION_MARK; 3154 FrameValues values; 3155 int frame_no = 0; 3156 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3157 fst.current()->describe(values, ++frame_no); 3158 if (depth == frame_no) break; 3159 } 3160 if (validate_only) { 3161 values.validate(); 3162 } else { 3163 tty->print_cr("[Describe stack layout]"); 3164 values.print(this); 3165 } 3166 } 3167 #endif 3168 3169 void JavaThread::trace_stack_from(vframe* start_vf) { 3170 ResourceMark rm; 3171 int vframe_no = 1; 3172 for (vframe* f = start_vf; f; f = f->sender() ) { 3173 if (f->is_java_frame()) { 3174 javaVFrame::cast(f)->print_activation(vframe_no++); 3175 } else { 3176 f->print(); 3177 } 3178 if (vframe_no > StackPrintLimit) { 3179 tty->print_cr("...<more frames>..."); 3180 return; 3181 } 3182 } 3183 } 3184 3185 3186 void JavaThread::trace_stack() { 3187 if (!has_last_Java_frame()) return; 3188 ResourceMark rm; 3189 HandleMark hm; 3190 RegisterMap reg_map(this); 3191 trace_stack_from(last_java_vframe(®_map)); 3192 } 3193 3194 3195 #endif // PRODUCT 3196 3197 3198 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3199 assert(reg_map != NULL, "a map must be given"); 3200 frame f = last_frame(); 3201 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3202 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3203 } 3204 return NULL; 3205 } 3206 3207 3208 Klass* JavaThread::security_get_caller_class(int depth) { 3209 vframeStream vfst(this); 3210 vfst.security_get_caller_frame(depth); 3211 if (!vfst.at_end()) { 3212 return vfst.method()->method_holder(); 3213 } 3214 return NULL; 3215 } 3216 3217 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3218 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3219 CompileBroker::compiler_thread_loop(); 3220 } 3221 3222 // Create a CompilerThread 3223 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3224 : JavaThread(&compiler_thread_entry) { 3225 _env = NULL; 3226 _log = NULL; 3227 _task = NULL; 3228 _queue = queue; 3229 _counters = counters; 3230 _buffer_blob = NULL; 3231 _scanned_nmethod = NULL; 3232 _compiler = NULL; 3233 3234 #ifndef PRODUCT 3235 _ideal_graph_printer = NULL; 3236 #endif 3237 } 3238 3239 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3240 JavaThread::oops_do(f, cld_f, cf); 3241 if (_scanned_nmethod != NULL && cf != NULL) { 3242 // Safepoints can occur when the sweeper is scanning an nmethod so 3243 // process it here to make sure it isn't unloaded in the middle of 3244 // a scan. 3245 cf->do_code_blob(_scanned_nmethod); 3246 } 3247 } 3248 3249 3250 // ======= Threads ======== 3251 3252 // The Threads class links together all active threads, and provides 3253 // operations over all threads. It is protected by its own Mutex 3254 // lock, which is also used in other contexts to protect thread 3255 // operations from having the thread being operated on from exiting 3256 // and going away unexpectedly (e.g., safepoint synchronization) 3257 3258 JavaThread* Threads::_thread_list = NULL; 3259 int Threads::_number_of_threads = 0; 3260 int Threads::_number_of_non_daemon_threads = 0; 3261 int Threads::_return_code = 0; 3262 size_t JavaThread::_stack_size_at_create = 0; 3263 #ifdef ASSERT 3264 bool Threads::_vm_complete = false; 3265 #endif 3266 3267 // All JavaThreads 3268 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3269 3270 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3271 void Threads::threads_do(ThreadClosure* tc) { 3272 assert_locked_or_safepoint(Threads_lock); 3273 // ALL_JAVA_THREADS iterates through all JavaThreads 3274 ALL_JAVA_THREADS(p) { 3275 tc->do_thread(p); 3276 } 3277 // Someday we could have a table or list of all non-JavaThreads. 3278 // For now, just manually iterate through them. 3279 tc->do_thread(VMThread::vm_thread()); 3280 Universe::heap()->gc_threads_do(tc); 3281 WatcherThread *wt = WatcherThread::watcher_thread(); 3282 // Strictly speaking, the following NULL check isn't sufficient to make sure 3283 // the data for WatcherThread is still valid upon being examined. However, 3284 // considering that WatchThread terminates when the VM is on the way to 3285 // exit at safepoint, the chance of the above is extremely small. The right 3286 // way to prevent termination of WatcherThread would be to acquire 3287 // Terminator_lock, but we can't do that without violating the lock rank 3288 // checking in some cases. 3289 if (wt != NULL) 3290 tc->do_thread(wt); 3291 3292 // If CompilerThreads ever become non-JavaThreads, add them here 3293 } 3294 3295 3296 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3297 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3298 3299 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3300 create_vm_init_libraries(); 3301 } 3302 3303 initialize_class(vmSymbols::java_lang_String(), CHECK); 3304 3305 // Initialize java_lang.System (needed before creating the thread) 3306 initialize_class(vmSymbols::java_lang_System(), CHECK); 3307 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3308 Handle thread_group = create_initial_thread_group(CHECK); 3309 Universe::set_main_thread_group(thread_group()); 3310 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3311 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3312 main_thread->set_threadObj(thread_object); 3313 // Set thread status to running since main thread has 3314 // been started and running. 3315 java_lang_Thread::set_thread_status(thread_object, 3316 java_lang_Thread::RUNNABLE); 3317 3318 // The VM creates & returns objects of this class. Make sure it's initialized. 3319 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3320 3321 // The VM preresolves methods to these classes. Make sure that they get initialized 3322 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3323 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3324 call_initializeSystemClass(CHECK); 3325 3326 // get the Java runtime name after java.lang.System is initialized 3327 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3328 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3329 3330 // an instance of OutOfMemory exception has been allocated earlier 3331 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3332 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3333 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3334 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3335 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3336 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3337 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3338 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3339 } 3340 3341 void Threads::initialize_jsr292_core_classes(TRAPS) { 3342 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3343 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3344 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3345 } 3346 3347 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3348 3349 extern void JDK_Version_init(); 3350 3351 // Check version 3352 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3353 3354 // Initialize the output stream module 3355 ostream_init(); 3356 3357 // Process java launcher properties. 3358 Arguments::process_sun_java_launcher_properties(args); 3359 3360 // Initialize the os module before using TLS 3361 os::init(); 3362 3363 // Initialize system properties. 3364 Arguments::init_system_properties(); 3365 3366 // So that JDK version can be used as a discriminator when parsing arguments 3367 JDK_Version_init(); 3368 3369 // Update/Initialize System properties after JDK version number is known 3370 Arguments::init_version_specific_system_properties(); 3371 3372 // Parse arguments 3373 jint parse_result = Arguments::parse(args); 3374 if (parse_result != JNI_OK) return parse_result; 3375 3376 os::init_before_ergo(); 3377 3378 jint ergo_result = Arguments::apply_ergo(); 3379 if (ergo_result != JNI_OK) return ergo_result; 3380 3381 if (PauseAtStartup) { 3382 os::pause(); 3383 } 3384 3385 HOTSPOT_VM_INIT_BEGIN(); 3386 3387 // Record VM creation timing statistics 3388 TraceVmCreationTime create_vm_timer; 3389 create_vm_timer.start(); 3390 3391 // Timing (must come after argument parsing) 3392 TraceTime timer("Create VM", TraceStartupTime); 3393 3394 // Initialize the os module after parsing the args 3395 jint os_init_2_result = os::init_2(); 3396 if (os_init_2_result != JNI_OK) return os_init_2_result; 3397 3398 jint adjust_after_os_result = Arguments::adjust_after_os(); 3399 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3400 3401 // initialize TLS 3402 ThreadLocalStorage::init(); 3403 3404 // Bootstrap native memory tracking, so it can start recording memory 3405 // activities before worker thread is started. This is the first phase 3406 // of bootstrapping, VM is currently running in single-thread mode. 3407 MemTracker::bootstrap_single_thread(); 3408 3409 // Initialize output stream logging 3410 ostream_init_log(); 3411 3412 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3413 // Must be before create_vm_init_agents() 3414 if (Arguments::init_libraries_at_startup()) { 3415 convert_vm_init_libraries_to_agents(); 3416 } 3417 3418 // Launch -agentlib/-agentpath and converted -Xrun agents 3419 if (Arguments::init_agents_at_startup()) { 3420 create_vm_init_agents(); 3421 } 3422 3423 // Initialize Threads state 3424 _thread_list = NULL; 3425 _number_of_threads = 0; 3426 _number_of_non_daemon_threads = 0; 3427 3428 // Initialize global data structures and create system classes in heap 3429 vm_init_globals(); 3430 3431 // Attach the main thread to this os thread 3432 JavaThread* main_thread = new JavaThread(); 3433 main_thread->set_thread_state(_thread_in_vm); 3434 // must do this before set_active_handles and initialize_thread_local_storage 3435 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3436 // change the stack size recorded here to one based on the java thread 3437 // stacksize. This adjusted size is what is used to figure the placement 3438 // of the guard pages. 3439 main_thread->record_stack_base_and_size(); 3440 main_thread->initialize_thread_local_storage(); 3441 3442 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3443 3444 if (!main_thread->set_as_starting_thread()) { 3445 vm_shutdown_during_initialization( 3446 "Failed necessary internal allocation. Out of swap space"); 3447 delete main_thread; 3448 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3449 return JNI_ENOMEM; 3450 } 3451 3452 // Enable guard page *after* os::create_main_thread(), otherwise it would 3453 // crash Linux VM, see notes in os_linux.cpp. 3454 main_thread->create_stack_guard_pages(); 3455 3456 // Initialize Java-Level synchronization subsystem 3457 ObjectMonitor::Initialize() ; 3458 3459 // Second phase of bootstrapping, VM is about entering multi-thread mode 3460 MemTracker::bootstrap_multi_thread(); 3461 3462 // Initialize global modules 3463 jint status = init_globals(); 3464 if (status != JNI_OK) { 3465 delete main_thread; 3466 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3467 return status; 3468 } 3469 3470 // Should be done after the heap is fully created 3471 main_thread->cache_global_variables(); 3472 3473 HandleMark hm; 3474 3475 { MutexLocker mu(Threads_lock); 3476 Threads::add(main_thread); 3477 } 3478 3479 // Any JVMTI raw monitors entered in onload will transition into 3480 // real raw monitor. VM is setup enough here for raw monitor enter. 3481 JvmtiExport::transition_pending_onload_raw_monitors(); 3482 3483 // Fully start NMT 3484 MemTracker::start(); 3485 3486 // Create the VMThread 3487 { TraceTime timer("Start VMThread", TraceStartupTime); 3488 VMThread::create(); 3489 Thread* vmthread = VMThread::vm_thread(); 3490 3491 if (!os::create_thread(vmthread, os::vm_thread)) 3492 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3493 3494 // Wait for the VM thread to become ready, and VMThread::run to initialize 3495 // Monitors can have spurious returns, must always check another state flag 3496 { 3497 MutexLocker ml(Notify_lock); 3498 os::start_thread(vmthread); 3499 while (vmthread->active_handles() == NULL) { 3500 Notify_lock->wait(); 3501 } 3502 } 3503 } 3504 3505 assert (Universe::is_fully_initialized(), "not initialized"); 3506 if (VerifyDuringStartup) { 3507 // Make sure we're starting with a clean slate. 3508 VM_Verify verify_op; 3509 VMThread::execute(&verify_op); 3510 } 3511 3512 Thread* THREAD = Thread::current(); 3513 3514 // At this point, the Universe is initialized, but we have not executed 3515 // any byte code. Now is a good time (the only time) to dump out the 3516 // internal state of the JVM for sharing. 3517 if (DumpSharedSpaces) { 3518 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3519 ShouldNotReachHere(); 3520 } 3521 3522 // Always call even when there are not JVMTI environments yet, since environments 3523 // may be attached late and JVMTI must track phases of VM execution 3524 JvmtiExport::enter_start_phase(); 3525 3526 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3527 JvmtiExport::post_vm_start(); 3528 3529 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3530 3531 // We need this for ClassDataSharing - the initial vm.info property is set 3532 // with the default value of CDS "sharing" which may be reset through 3533 // command line options. 3534 reset_vm_info_property(CHECK_JNI_ERR); 3535 3536 quicken_jni_functions(); 3537 3538 // Must be run after init_ft which initializes ft_enabled 3539 if (TRACE_INITIALIZE() != JNI_OK) { 3540 vm_exit_during_initialization("Failed to initialize tracing backend"); 3541 } 3542 3543 // Set flag that basic initialization has completed. Used by exceptions and various 3544 // debug stuff, that does not work until all basic classes have been initialized. 3545 set_init_completed(); 3546 3547 HOTSPOT_VM_INIT_END(); 3548 3549 // record VM initialization completion time 3550 #if INCLUDE_MANAGEMENT 3551 Management::record_vm_init_completed(); 3552 #endif // INCLUDE_MANAGEMENT 3553 3554 // Compute system loader. Note that this has to occur after set_init_completed, since 3555 // valid exceptions may be thrown in the process. 3556 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3557 // set_init_completed has just been called, causing exceptions not to be shortcut 3558 // anymore. We call vm_exit_during_initialization directly instead. 3559 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR); 3560 3561 #if INCLUDE_ALL_GCS 3562 // Support for ConcurrentMarkSweep. This should be cleaned up 3563 // and better encapsulated. The ugly nested if test would go away 3564 // once things are properly refactored. XXX YSR 3565 if (UseConcMarkSweepGC || UseG1GC) { 3566 if (UseConcMarkSweepGC) { 3567 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3568 } else { 3569 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3570 } 3571 } 3572 #endif // INCLUDE_ALL_GCS 3573 3574 // Always call even when there are not JVMTI environments yet, since environments 3575 // may be attached late and JVMTI must track phases of VM execution 3576 JvmtiExport::enter_live_phase(); 3577 3578 // Signal Dispatcher needs to be started before VMInit event is posted 3579 os::signal_init(); 3580 3581 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3582 if (!DisableAttachMechanism) { 3583 AttachListener::vm_start(); 3584 if (StartAttachListener || AttachListener::init_at_startup()) { 3585 AttachListener::init(); 3586 } 3587 } 3588 3589 // Launch -Xrun agents 3590 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3591 // back-end can launch with -Xdebug -Xrunjdwp. 3592 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3593 create_vm_init_libraries(); 3594 } 3595 3596 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3597 JvmtiExport::post_vm_initialized(); 3598 3599 if (TRACE_START() != JNI_OK) { 3600 vm_exit_during_initialization("Failed to start tracing backend."); 3601 } 3602 3603 if (CleanChunkPoolAsync) { 3604 Chunk::start_chunk_pool_cleaner_task(); 3605 } 3606 3607 // initialize compiler(s) 3608 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3609 CompileBroker::compilation_init(); 3610 #endif 3611 3612 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3613 // It is done after compilers are initialized, because otherwise compilations of 3614 // signature polymorphic MH intrinsics can be missed 3615 // (see SystemDictionary::find_method_handle_intrinsic). 3616 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3617 3618 #if INCLUDE_MANAGEMENT 3619 Management::initialize(THREAD); 3620 3621 if (HAS_PENDING_EXCEPTION) { 3622 // management agent fails to start possibly due to 3623 // configuration problem and is responsible for printing 3624 // stack trace if appropriate. Simply exit VM. 3625 vm_exit(1); 3626 } 3627 #endif // INCLUDE_MANAGEMENT 3628 3629 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3630 if (MemProfiling) MemProfiler::engage(); 3631 StatSampler::engage(); 3632 if (CheckJNICalls) JniPeriodicChecker::engage(); 3633 3634 BiasedLocking::init(); 3635 3636 #if INCLUDE_RTM_OPT 3637 RTMLockingCounters::init(); 3638 #endif 3639 3640 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3641 call_postVMInitHook(THREAD); 3642 // The Java side of PostVMInitHook.run must deal with all 3643 // exceptions and provide means of diagnosis. 3644 if (HAS_PENDING_EXCEPTION) { 3645 CLEAR_PENDING_EXCEPTION; 3646 } 3647 } 3648 3649 { 3650 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3651 // Make sure the watcher thread can be started by WatcherThread::start() 3652 // or by dynamic enrollment. 3653 WatcherThread::make_startable(); 3654 // Start up the WatcherThread if there are any periodic tasks 3655 // NOTE: All PeriodicTasks should be registered by now. If they 3656 // aren't, late joiners might appear to start slowly (we might 3657 // take a while to process their first tick). 3658 if (PeriodicTask::num_tasks() > 0) { 3659 WatcherThread::start(); 3660 } 3661 } 3662 3663 // Give os specific code one last chance to start 3664 os::init_3(); 3665 3666 create_vm_timer.end(); 3667 #ifdef ASSERT 3668 _vm_complete = true; 3669 #endif 3670 return JNI_OK; 3671 } 3672 3673 // type for the Agent_OnLoad and JVM_OnLoad entry points 3674 extern "C" { 3675 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3676 } 3677 // Find a command line agent library and return its entry point for 3678 // -agentlib: -agentpath: -Xrun 3679 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3680 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3681 OnLoadEntry_t on_load_entry = NULL; 3682 void *library = NULL; 3683 3684 if (!agent->valid()) { 3685 char buffer[JVM_MAXPATHLEN]; 3686 char ebuf[1024]; 3687 const char *name = agent->name(); 3688 const char *msg = "Could not find agent library "; 3689 3690 // First check to see if agent is statically linked into executable 3691 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3692 library = agent->os_lib(); 3693 } else if (agent->is_absolute_path()) { 3694 library = os::dll_load(name, ebuf, sizeof ebuf); 3695 if (library == NULL) { 3696 const char *sub_msg = " in absolute path, with error: "; 3697 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3698 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3699 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3700 // If we can't find the agent, exit. 3701 vm_exit_during_initialization(buf, NULL); 3702 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3703 } 3704 } else { 3705 // Try to load the agent from the standard dll directory 3706 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3707 name)) { 3708 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3709 } 3710 if (library == NULL) { // Try the local directory 3711 char ns[1] = {0}; 3712 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3713 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3714 } 3715 if (library == NULL) { 3716 const char *sub_msg = " on the library path, with error: "; 3717 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3718 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3719 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3720 // If we can't find the agent, exit. 3721 vm_exit_during_initialization(buf, NULL); 3722 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3723 } 3724 } 3725 } 3726 agent->set_os_lib(library); 3727 agent->set_valid(); 3728 } 3729 3730 // Find the OnLoad function. 3731 on_load_entry = 3732 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3733 false, 3734 on_load_symbols, 3735 num_symbol_entries)); 3736 return on_load_entry; 3737 } 3738 3739 // Find the JVM_OnLoad entry point 3740 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3741 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3742 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3743 } 3744 3745 // Find the Agent_OnLoad entry point 3746 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3747 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3748 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3749 } 3750 3751 // For backwards compatibility with -Xrun 3752 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3753 // treated like -agentpath: 3754 // Must be called before agent libraries are created 3755 void Threads::convert_vm_init_libraries_to_agents() { 3756 AgentLibrary* agent; 3757 AgentLibrary* next; 3758 3759 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3760 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3761 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3762 3763 // If there is an JVM_OnLoad function it will get called later, 3764 // otherwise see if there is an Agent_OnLoad 3765 if (on_load_entry == NULL) { 3766 on_load_entry = lookup_agent_on_load(agent); 3767 if (on_load_entry != NULL) { 3768 // switch it to the agent list -- so that Agent_OnLoad will be called, 3769 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3770 Arguments::convert_library_to_agent(agent); 3771 } else { 3772 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3773 } 3774 } 3775 } 3776 } 3777 3778 // Create agents for -agentlib: -agentpath: and converted -Xrun 3779 // Invokes Agent_OnLoad 3780 // Called very early -- before JavaThreads exist 3781 void Threads::create_vm_init_agents() { 3782 extern struct JavaVM_ main_vm; 3783 AgentLibrary* agent; 3784 3785 JvmtiExport::enter_onload_phase(); 3786 3787 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3788 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3789 3790 if (on_load_entry != NULL) { 3791 // Invoke the Agent_OnLoad function 3792 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3793 if (err != JNI_OK) { 3794 vm_exit_during_initialization("agent library failed to init", agent->name()); 3795 } 3796 } else { 3797 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3798 } 3799 } 3800 JvmtiExport::enter_primordial_phase(); 3801 } 3802 3803 extern "C" { 3804 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3805 } 3806 3807 void Threads::shutdown_vm_agents() { 3808 // Send any Agent_OnUnload notifications 3809 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3810 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3811 extern struct JavaVM_ main_vm; 3812 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3813 3814 // Find the Agent_OnUnload function. 3815 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3816 os::find_agent_function(agent, 3817 false, 3818 on_unload_symbols, 3819 num_symbol_entries)); 3820 3821 // Invoke the Agent_OnUnload function 3822 if (unload_entry != NULL) { 3823 JavaThread* thread = JavaThread::current(); 3824 ThreadToNativeFromVM ttn(thread); 3825 HandleMark hm(thread); 3826 (*unload_entry)(&main_vm); 3827 } 3828 } 3829 } 3830 3831 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3832 // Invokes JVM_OnLoad 3833 void Threads::create_vm_init_libraries() { 3834 extern struct JavaVM_ main_vm; 3835 AgentLibrary* agent; 3836 3837 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3838 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3839 3840 if (on_load_entry != NULL) { 3841 // Invoke the JVM_OnLoad function 3842 JavaThread* thread = JavaThread::current(); 3843 ThreadToNativeFromVM ttn(thread); 3844 HandleMark hm(thread); 3845 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3846 if (err != JNI_OK) { 3847 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3848 } 3849 } else { 3850 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3851 } 3852 } 3853 } 3854 3855 // Last thread running calls java.lang.Shutdown.shutdown() 3856 void JavaThread::invoke_shutdown_hooks() { 3857 HandleMark hm(this); 3858 3859 // We could get here with a pending exception, if so clear it now. 3860 if (this->has_pending_exception()) { 3861 this->clear_pending_exception(); 3862 } 3863 3864 EXCEPTION_MARK; 3865 Klass* k = 3866 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3867 THREAD); 3868 if (k != NULL) { 3869 // SystemDictionary::resolve_or_null will return null if there was 3870 // an exception. If we cannot load the Shutdown class, just don't 3871 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3872 // and finalizers (if runFinalizersOnExit is set) won't be run. 3873 // Note that if a shutdown hook was registered or runFinalizersOnExit 3874 // was called, the Shutdown class would have already been loaded 3875 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3876 instanceKlassHandle shutdown_klass (THREAD, k); 3877 JavaValue result(T_VOID); 3878 JavaCalls::call_static(&result, 3879 shutdown_klass, 3880 vmSymbols::shutdown_method_name(), 3881 vmSymbols::void_method_signature(), 3882 THREAD); 3883 } 3884 CLEAR_PENDING_EXCEPTION; 3885 } 3886 3887 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3888 // the program falls off the end of main(). Another VM exit path is through 3889 // vm_exit() when the program calls System.exit() to return a value or when 3890 // there is a serious error in VM. The two shutdown paths are not exactly 3891 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3892 // and VM_Exit op at VM level. 3893 // 3894 // Shutdown sequence: 3895 // + Shutdown native memory tracking if it is on 3896 // + Wait until we are the last non-daemon thread to execute 3897 // <-- every thing is still working at this moment --> 3898 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3899 // shutdown hooks, run finalizers if finalization-on-exit 3900 // + Call before_exit(), prepare for VM exit 3901 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3902 // currently the only user of this mechanism is File.deleteOnExit()) 3903 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3904 // post thread end and vm death events to JVMTI, 3905 // stop signal thread 3906 // + Call JavaThread::exit(), it will: 3907 // > release JNI handle blocks, remove stack guard pages 3908 // > remove this thread from Threads list 3909 // <-- no more Java code from this thread after this point --> 3910 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3911 // the compiler threads at safepoint 3912 // <-- do not use anything that could get blocked by Safepoint --> 3913 // + Disable tracing at JNI/JVM barriers 3914 // + Set _vm_exited flag for threads that are still running native code 3915 // + Delete this thread 3916 // + Call exit_globals() 3917 // > deletes tty 3918 // > deletes PerfMemory resources 3919 // + Return to caller 3920 3921 bool Threads::destroy_vm() { 3922 JavaThread* thread = JavaThread::current(); 3923 3924 #ifdef ASSERT 3925 _vm_complete = false; 3926 #endif 3927 // Wait until we are the last non-daemon thread to execute 3928 { MutexLocker nu(Threads_lock); 3929 while (Threads::number_of_non_daemon_threads() > 1 ) 3930 // This wait should make safepoint checks, wait without a timeout, 3931 // and wait as a suspend-equivalent condition. 3932 // 3933 // Note: If the FlatProfiler is running and this thread is waiting 3934 // for another non-daemon thread to finish, then the FlatProfiler 3935 // is waiting for the external suspend request on this thread to 3936 // complete. wait_for_ext_suspend_completion() will eventually 3937 // timeout, but that takes time. Making this wait a suspend- 3938 // equivalent condition solves that timeout problem. 3939 // 3940 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3941 Mutex::_as_suspend_equivalent_flag); 3942 } 3943 3944 // Hang forever on exit if we are reporting an error. 3945 if (ShowMessageBoxOnError && is_error_reported()) { 3946 os::infinite_sleep(); 3947 } 3948 os::wait_for_keypress_at_exit(); 3949 3950 if (JDK_Version::is_jdk12x_version()) { 3951 // We are the last thread running, so check if finalizers should be run. 3952 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3953 HandleMark rm(thread); 3954 Universe::run_finalizers_on_exit(); 3955 } else { 3956 // run Java level shutdown hooks 3957 thread->invoke_shutdown_hooks(); 3958 } 3959 3960 before_exit(thread); 3961 3962 thread->exit(true); 3963 3964 // Stop VM thread. 3965 { 3966 // 4945125 The vm thread comes to a safepoint during exit. 3967 // GC vm_operations can get caught at the safepoint, and the 3968 // heap is unparseable if they are caught. Grab the Heap_lock 3969 // to prevent this. The GC vm_operations will not be able to 3970 // queue until after the vm thread is dead. 3971 // After this point, we'll never emerge out of the safepoint before 3972 // the VM exits, so concurrent GC threads do not need to be explicitly 3973 // stopped; they remain inactive until the process exits. 3974 // Note: some concurrent G1 threads may be running during a safepoint, 3975 // but these will not be accessing the heap, just some G1-specific side 3976 // data structures that are not accessed by any other threads but them 3977 // after this point in a terminal safepoint. 3978 3979 MutexLocker ml(Heap_lock); 3980 3981 VMThread::wait_for_vm_thread_exit(); 3982 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3983 VMThread::destroy(); 3984 } 3985 3986 // clean up ideal graph printers 3987 #if defined(COMPILER2) && !defined(PRODUCT) 3988 IdealGraphPrinter::clean_up(); 3989 #endif 3990 3991 // Now, all Java threads are gone except daemon threads. Daemon threads 3992 // running Java code or in VM are stopped by the Safepoint. However, 3993 // daemon threads executing native code are still running. But they 3994 // will be stopped at native=>Java/VM barriers. Note that we can't 3995 // simply kill or suspend them, as it is inherently deadlock-prone. 3996 3997 #ifndef PRODUCT 3998 // disable function tracing at JNI/JVM barriers 3999 TraceJNICalls = false; 4000 TraceJVMCalls = false; 4001 TraceRuntimeCalls = false; 4002 #endif 4003 4004 VM_Exit::set_vm_exited(); 4005 4006 notify_vm_shutdown(); 4007 4008 delete thread; 4009 4010 // exit_globals() will delete tty 4011 exit_globals(); 4012 4013 return true; 4014 } 4015 4016 4017 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4018 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4019 return is_supported_jni_version(version); 4020 } 4021 4022 4023 jboolean Threads::is_supported_jni_version(jint version) { 4024 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4025 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4026 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4027 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4028 return JNI_FALSE; 4029 } 4030 4031 4032 void Threads::add(JavaThread* p, bool force_daemon) { 4033 // The threads lock must be owned at this point 4034 assert_locked_or_safepoint(Threads_lock); 4035 4036 // See the comment for this method in thread.hpp for its purpose and 4037 // why it is called here. 4038 p->initialize_queues(); 4039 p->set_next(_thread_list); 4040 _thread_list = p; 4041 _number_of_threads++; 4042 oop threadObj = p->threadObj(); 4043 bool daemon = true; 4044 // Bootstrapping problem: threadObj can be null for initial 4045 // JavaThread (or for threads attached via JNI) 4046 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4047 _number_of_non_daemon_threads++; 4048 daemon = false; 4049 } 4050 4051 p->set_safepoint_visible(true); 4052 4053 ThreadService::add_thread(p, daemon); 4054 4055 // Possible GC point. 4056 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4057 } 4058 4059 void Threads::remove(JavaThread* p) { 4060 // Extra scope needed for Thread_lock, so we can check 4061 // that we do not remove thread without safepoint code notice 4062 { MutexLocker ml(Threads_lock); 4063 4064 assert(includes(p), "p must be present"); 4065 4066 JavaThread* current = _thread_list; 4067 JavaThread* prev = NULL; 4068 4069 while (current != p) { 4070 prev = current; 4071 current = current->next(); 4072 } 4073 4074 if (prev) { 4075 prev->set_next(current->next()); 4076 } else { 4077 _thread_list = p->next(); 4078 } 4079 _number_of_threads--; 4080 oop threadObj = p->threadObj(); 4081 bool daemon = true; 4082 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4083 _number_of_non_daemon_threads--; 4084 daemon = false; 4085 4086 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4087 // on destroy_vm will wake up. 4088 if (number_of_non_daemon_threads() == 1) 4089 Threads_lock->notify_all(); 4090 } 4091 ThreadService::remove_thread(p, daemon); 4092 4093 // Make sure that safepoint code disregard this thread. This is needed since 4094 // the thread might mess around with locks after this point. This can cause it 4095 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4096 // of this thread since it is removed from the queue. 4097 p->set_terminated_value(); 4098 4099 // Now, this thread is not visible to safepoint 4100 p->set_safepoint_visible(false); 4101 // once the thread becomes safepoint invisible, we can not use its per-thread 4102 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4103 // to release its per-thread recorder here. 4104 MemTracker::thread_exiting(p); 4105 } // unlock Threads_lock 4106 4107 // Since Events::log uses a lock, we grab it outside the Threads_lock 4108 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4109 } 4110 4111 // Threads_lock must be held when this is called (or must be called during a safepoint) 4112 bool Threads::includes(JavaThread* p) { 4113 assert(Threads_lock->is_locked(), "sanity check"); 4114 ALL_JAVA_THREADS(q) { 4115 if (q == p ) { 4116 return true; 4117 } 4118 } 4119 return false; 4120 } 4121 4122 // Operations on the Threads list for GC. These are not explicitly locked, 4123 // but the garbage collector must provide a safe context for them to run. 4124 // In particular, these things should never be called when the Threads_lock 4125 // is held by some other thread. (Note: the Safepoint abstraction also 4126 // uses the Threads_lock to guarantee this property. It also makes sure that 4127 // all threads gets blocked when exiting or starting). 4128 4129 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4130 ALL_JAVA_THREADS(p) { 4131 p->oops_do(f, cld_f, cf); 4132 } 4133 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4134 } 4135 4136 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4137 // Introduce a mechanism allowing parallel threads to claim threads as 4138 // root groups. Overhead should be small enough to use all the time, 4139 // even in sequential code. 4140 SharedHeap* sh = SharedHeap::heap(); 4141 // Cannot yet substitute active_workers for n_par_threads 4142 // because of G1CollectedHeap::verify() use of 4143 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4144 // turn off parallelism in process_strong_roots while active_workers 4145 // is being used for parallelism elsewhere. 4146 bool is_par = sh->n_par_threads() > 0; 4147 assert(!is_par || 4148 (SharedHeap::heap()->n_par_threads() == 4149 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4150 int cp = SharedHeap::heap()->strong_roots_parity(); 4151 ALL_JAVA_THREADS(p) { 4152 if (p->claim_oops_do(is_par, cp)) { 4153 p->oops_do(f, cld_f, cf); 4154 } 4155 } 4156 VMThread* vmt = VMThread::vm_thread(); 4157 if (vmt->claim_oops_do(is_par, cp)) { 4158 vmt->oops_do(f, cld_f, cf); 4159 } 4160 } 4161 4162 #if INCLUDE_ALL_GCS 4163 // Used by ParallelScavenge 4164 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4165 ALL_JAVA_THREADS(p) { 4166 q->enqueue(new ThreadRootsTask(p)); 4167 } 4168 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4169 } 4170 4171 // Used by Parallel Old 4172 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4173 ALL_JAVA_THREADS(p) { 4174 q->enqueue(new ThreadRootsMarkingTask(p)); 4175 } 4176 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4177 } 4178 #endif // INCLUDE_ALL_GCS 4179 4180 void Threads::nmethods_do(CodeBlobClosure* cf) { 4181 ALL_JAVA_THREADS(p) { 4182 p->nmethods_do(cf); 4183 } 4184 VMThread::vm_thread()->nmethods_do(cf); 4185 } 4186 4187 void Threads::metadata_do(void f(Metadata*)) { 4188 ALL_JAVA_THREADS(p) { 4189 p->metadata_do(f); 4190 } 4191 } 4192 4193 void Threads::gc_epilogue() { 4194 ALL_JAVA_THREADS(p) { 4195 p->gc_epilogue(); 4196 } 4197 } 4198 4199 void Threads::gc_prologue() { 4200 ALL_JAVA_THREADS(p) { 4201 p->gc_prologue(); 4202 } 4203 } 4204 4205 void Threads::deoptimized_wrt_marked_nmethods() { 4206 ALL_JAVA_THREADS(p) { 4207 p->deoptimized_wrt_marked_nmethods(); 4208 } 4209 } 4210 4211 4212 // Get count Java threads that are waiting to enter the specified monitor. 4213 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4214 address monitor, bool doLock) { 4215 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4216 "must grab Threads_lock or be at safepoint"); 4217 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4218 4219 int i = 0; 4220 { 4221 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4222 ALL_JAVA_THREADS(p) { 4223 if (p->is_Compiler_thread()) continue; 4224 4225 address pending = (address)p->current_pending_monitor(); 4226 if (pending == monitor) { // found a match 4227 if (i < count) result->append(p); // save the first count matches 4228 i++; 4229 } 4230 } 4231 } 4232 return result; 4233 } 4234 4235 4236 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4237 assert(doLock || 4238 Threads_lock->owned_by_self() || 4239 SafepointSynchronize::is_at_safepoint(), 4240 "must grab Threads_lock or be at safepoint"); 4241 4242 // NULL owner means not locked so we can skip the search 4243 if (owner == NULL) return NULL; 4244 4245 { 4246 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4247 ALL_JAVA_THREADS(p) { 4248 // first, see if owner is the address of a Java thread 4249 if (owner == (address)p) return p; 4250 } 4251 } 4252 // Cannot assert on lack of success here since this function may be 4253 // used by code that is trying to report useful problem information 4254 // like deadlock detection. 4255 if (UseHeavyMonitors) return NULL; 4256 4257 // 4258 // If we didn't find a matching Java thread and we didn't force use of 4259 // heavyweight monitors, then the owner is the stack address of the 4260 // Lock Word in the owning Java thread's stack. 4261 // 4262 JavaThread* the_owner = NULL; 4263 { 4264 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4265 ALL_JAVA_THREADS(q) { 4266 if (q->is_lock_owned(owner)) { 4267 the_owner = q; 4268 break; 4269 } 4270 } 4271 } 4272 // cannot assert on lack of success here; see above comment 4273 return the_owner; 4274 } 4275 4276 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4277 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4278 char buf[32]; 4279 st->print_cr("%s", os::local_time_string(buf, sizeof(buf))); 4280 4281 st->print_cr("Full thread dump %s (%s %s):", 4282 Abstract_VM_Version::vm_name(), 4283 Abstract_VM_Version::vm_release(), 4284 Abstract_VM_Version::vm_info_string() 4285 ); 4286 st->cr(); 4287 4288 #if INCLUDE_ALL_GCS 4289 // Dump concurrent locks 4290 ConcurrentLocksDump concurrent_locks; 4291 if (print_concurrent_locks) { 4292 concurrent_locks.dump_at_safepoint(); 4293 } 4294 #endif // INCLUDE_ALL_GCS 4295 4296 ALL_JAVA_THREADS(p) { 4297 ResourceMark rm; 4298 p->print_on(st); 4299 if (print_stacks) { 4300 if (internal_format) { 4301 p->trace_stack(); 4302 } else { 4303 p->print_stack_on(st); 4304 } 4305 } 4306 st->cr(); 4307 #if INCLUDE_ALL_GCS 4308 if (print_concurrent_locks) { 4309 concurrent_locks.print_locks_on(p, st); 4310 } 4311 #endif // INCLUDE_ALL_GCS 4312 } 4313 4314 VMThread::vm_thread()->print_on(st); 4315 st->cr(); 4316 Universe::heap()->print_gc_threads_on(st); 4317 WatcherThread* wt = WatcherThread::watcher_thread(); 4318 if (wt != NULL) { 4319 wt->print_on(st); 4320 st->cr(); 4321 } 4322 CompileBroker::print_compiler_threads_on(st); 4323 st->flush(); 4324 } 4325 4326 // Threads::print_on_error() is called by fatal error handler. It's possible 4327 // that VM is not at safepoint and/or current thread is inside signal handler. 4328 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4329 // memory (even in resource area), it might deadlock the error handler. 4330 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4331 bool found_current = false; 4332 st->print_cr("Java Threads: ( => current thread )"); 4333 ALL_JAVA_THREADS(thread) { 4334 bool is_current = (current == thread); 4335 found_current = found_current || is_current; 4336 4337 st->print("%s", is_current ? "=>" : " "); 4338 4339 st->print(PTR_FORMAT, thread); 4340 st->print(" "); 4341 thread->print_on_error(st, buf, buflen); 4342 st->cr(); 4343 } 4344 st->cr(); 4345 4346 st->print_cr("Other Threads:"); 4347 if (VMThread::vm_thread()) { 4348 bool is_current = (current == VMThread::vm_thread()); 4349 found_current = found_current || is_current; 4350 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4351 4352 st->print(PTR_FORMAT, VMThread::vm_thread()); 4353 st->print(" "); 4354 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4355 st->cr(); 4356 } 4357 WatcherThread* wt = WatcherThread::watcher_thread(); 4358 if (wt != NULL) { 4359 bool is_current = (current == wt); 4360 found_current = found_current || is_current; 4361 st->print("%s", is_current ? "=>" : " "); 4362 4363 st->print(PTR_FORMAT, wt); 4364 st->print(" "); 4365 wt->print_on_error(st, buf, buflen); 4366 st->cr(); 4367 } 4368 if (!found_current) { 4369 st->cr(); 4370 st->print("=>" PTR_FORMAT " (exited) ", current); 4371 current->print_on_error(st, buf, buflen); 4372 st->cr(); 4373 } 4374 } 4375 4376 // Internal SpinLock and Mutex 4377 // Based on ParkEvent 4378 4379 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4380 // 4381 // We employ SpinLocks _only for low-contention, fixed-length 4382 // short-duration critical sections where we're concerned 4383 // about native mutex_t or HotSpot Mutex:: latency. 4384 // The mux construct provides a spin-then-block mutual exclusion 4385 // mechanism. 4386 // 4387 // Testing has shown that contention on the ListLock guarding gFreeList 4388 // is common. If we implement ListLock as a simple SpinLock it's common 4389 // for the JVM to devolve to yielding with little progress. This is true 4390 // despite the fact that the critical sections protected by ListLock are 4391 // extremely short. 4392 // 4393 // TODO-FIXME: ListLock should be of type SpinLock. 4394 // We should make this a 1st-class type, integrated into the lock 4395 // hierarchy as leaf-locks. Critically, the SpinLock structure 4396 // should have sufficient padding to avoid false-sharing and excessive 4397 // cache-coherency traffic. 4398 4399 4400 typedef volatile int SpinLockT ; 4401 4402 void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4403 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4404 return ; // normal fast-path return 4405 } 4406 4407 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4408 TEVENT (SpinAcquire - ctx) ; 4409 int ctr = 0 ; 4410 int Yields = 0 ; 4411 for (;;) { 4412 while (*adr != 0) { 4413 ++ctr ; 4414 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4415 if (Yields > 5) { 4416 os::naked_short_sleep(1); 4417 } else { 4418 os::NakedYield() ; 4419 ++Yields ; 4420 } 4421 } else { 4422 SpinPause() ; 4423 } 4424 } 4425 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4426 } 4427 } 4428 4429 void Thread::SpinRelease (volatile int * adr) { 4430 assert (*adr != 0, "invariant") ; 4431 OrderAccess::fence() ; // guarantee at least release consistency. 4432 // Roach-motel semantics. 4433 // It's safe if subsequent LDs and STs float "up" into the critical section, 4434 // but prior LDs and STs within the critical section can't be allowed 4435 // to reorder or float past the ST that releases the lock. 4436 *adr = 0 ; 4437 } 4438 4439 // muxAcquire and muxRelease: 4440 // 4441 // * muxAcquire and muxRelease support a single-word lock-word construct. 4442 // The LSB of the word is set IFF the lock is held. 4443 // The remainder of the word points to the head of a singly-linked list 4444 // of threads blocked on the lock. 4445 // 4446 // * The current implementation of muxAcquire-muxRelease uses its own 4447 // dedicated Thread._MuxEvent instance. If we're interested in 4448 // minimizing the peak number of extant ParkEvent instances then 4449 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4450 // as certain invariants were satisfied. Specifically, care would need 4451 // to be taken with regards to consuming unpark() "permits". 4452 // A safe rule of thumb is that a thread would never call muxAcquire() 4453 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4454 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4455 // consume an unpark() permit intended for monitorenter, for instance. 4456 // One way around this would be to widen the restricted-range semaphore 4457 // implemented in park(). Another alternative would be to provide 4458 // multiple instances of the PlatformEvent() for each thread. One 4459 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4460 // 4461 // * Usage: 4462 // -- Only as leaf locks 4463 // -- for short-term locking only as muxAcquire does not perform 4464 // thread state transitions. 4465 // 4466 // Alternatives: 4467 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4468 // but with parking or spin-then-park instead of pure spinning. 4469 // * Use Taura-Oyama-Yonenzawa locks. 4470 // * It's possible to construct a 1-0 lock if we encode the lockword as 4471 // (List,LockByte). Acquire will CAS the full lockword while Release 4472 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4473 // acquiring threads use timers (ParkTimed) to detect and recover from 4474 // the stranding window. Thread/Node structures must be aligned on 256-byte 4475 // boundaries by using placement-new. 4476 // * Augment MCS with advisory back-link fields maintained with CAS(). 4477 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4478 // The validity of the backlinks must be ratified before we trust the value. 4479 // If the backlinks are invalid the exiting thread must back-track through the 4480 // the forward links, which are always trustworthy. 4481 // * Add a successor indication. The LockWord is currently encoded as 4482 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4483 // to provide the usual futile-wakeup optimization. 4484 // See RTStt for details. 4485 // * Consider schedctl.sc_nopreempt to cover the critical section. 4486 // 4487 4488 4489 typedef volatile intptr_t MutexT ; // Mux Lock-word 4490 enum MuxBits { LOCKBIT = 1 } ; 4491 4492 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4493 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4494 if (w == 0) return ; 4495 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4496 return ; 4497 } 4498 4499 TEVENT (muxAcquire - Contention) ; 4500 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4501 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4502 for (;;) { 4503 int its = (os::is_MP() ? 100 : 0) + 1 ; 4504 4505 // Optional spin phase: spin-then-park strategy 4506 while (--its >= 0) { 4507 w = *Lock ; 4508 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4509 return ; 4510 } 4511 } 4512 4513 Self->reset() ; 4514 Self->OnList = intptr_t(Lock) ; 4515 // The following fence() isn't _strictly necessary as the subsequent 4516 // CAS() both serializes execution and ratifies the fetched *Lock value. 4517 OrderAccess::fence(); 4518 for (;;) { 4519 w = *Lock ; 4520 if ((w & LOCKBIT) == 0) { 4521 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4522 Self->OnList = 0 ; // hygiene - allows stronger asserts 4523 return ; 4524 } 4525 continue ; // Interference -- *Lock changed -- Just retry 4526 } 4527 assert (w & LOCKBIT, "invariant") ; 4528 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4529 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4530 } 4531 4532 while (Self->OnList != 0) { 4533 Self->park() ; 4534 } 4535 } 4536 } 4537 4538 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4539 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4540 if (w == 0) return ; 4541 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4542 return ; 4543 } 4544 4545 TEVENT (muxAcquire - Contention) ; 4546 ParkEvent * ReleaseAfter = NULL ; 4547 if (ev == NULL) { 4548 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4549 } 4550 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4551 for (;;) { 4552 guarantee (ev->OnList == 0, "invariant") ; 4553 int its = (os::is_MP() ? 100 : 0) + 1 ; 4554 4555 // Optional spin phase: spin-then-park strategy 4556 while (--its >= 0) { 4557 w = *Lock ; 4558 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4559 if (ReleaseAfter != NULL) { 4560 ParkEvent::Release (ReleaseAfter) ; 4561 } 4562 return ; 4563 } 4564 } 4565 4566 ev->reset() ; 4567 ev->OnList = intptr_t(Lock) ; 4568 // The following fence() isn't _strictly necessary as the subsequent 4569 // CAS() both serializes execution and ratifies the fetched *Lock value. 4570 OrderAccess::fence(); 4571 for (;;) { 4572 w = *Lock ; 4573 if ((w & LOCKBIT) == 0) { 4574 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4575 ev->OnList = 0 ; 4576 // We call ::Release while holding the outer lock, thus 4577 // artificially lengthening the critical section. 4578 // Consider deferring the ::Release() until the subsequent unlock(), 4579 // after we've dropped the outer lock. 4580 if (ReleaseAfter != NULL) { 4581 ParkEvent::Release (ReleaseAfter) ; 4582 } 4583 return ; 4584 } 4585 continue ; // Interference -- *Lock changed -- Just retry 4586 } 4587 assert (w & LOCKBIT, "invariant") ; 4588 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4589 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4590 } 4591 4592 while (ev->OnList != 0) { 4593 ev->park() ; 4594 } 4595 } 4596 } 4597 4598 // Release() must extract a successor from the list and then wake that thread. 4599 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4600 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4601 // Release() would : 4602 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4603 // (B) Extract a successor from the private list "in-hand" 4604 // (C) attempt to CAS() the residual back into *Lock over null. 4605 // If there were any newly arrived threads and the CAS() would fail. 4606 // In that case Release() would detach the RATs, re-merge the list in-hand 4607 // with the RATs and repeat as needed. Alternately, Release() might 4608 // detach and extract a successor, but then pass the residual list to the wakee. 4609 // The wakee would be responsible for reattaching and remerging before it 4610 // competed for the lock. 4611 // 4612 // Both "pop" and DMR are immune from ABA corruption -- there can be 4613 // multiple concurrent pushers, but only one popper or detacher. 4614 // This implementation pops from the head of the list. This is unfair, 4615 // but tends to provide excellent throughput as hot threads remain hot. 4616 // (We wake recently run threads first). 4617 4618 void Thread::muxRelease (volatile intptr_t * Lock) { 4619 for (;;) { 4620 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4621 assert (w & LOCKBIT, "invariant") ; 4622 if (w == LOCKBIT) return ; 4623 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4624 assert (List != NULL, "invariant") ; 4625 assert (List->OnList == intptr_t(Lock), "invariant") ; 4626 ParkEvent * nxt = List->ListNext ; 4627 4628 // The following CAS() releases the lock and pops the head element. 4629 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4630 continue ; 4631 } 4632 List->OnList = 0 ; 4633 OrderAccess::fence() ; 4634 List->unpark () ; 4635 return ; 4636 } 4637 } 4638 4639 4640 void Threads::verify() { 4641 ALL_JAVA_THREADS(p) { 4642 p->verify(); 4643 } 4644 VMThread* thread = VMThread::vm_thread(); 4645 if (thread != NULL) thread->verify(); 4646 }