1 /* 2 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/classLoader.hpp" 27 #include "classfile/javaClasses.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/codeCache.hpp" 31 #include "code/codeCacheExtensions.hpp" 32 #include "code/scopeDesc.hpp" 33 #include "compiler/compileBroker.hpp" 34 #include "compiler/compileTask.hpp" 35 #include "gc/shared/gcId.hpp" 36 #include "gc/shared/gcLocker.inline.hpp" 37 #include "gc/shared/workgroup.hpp" 38 #include "interpreter/interpreter.hpp" 39 #include "interpreter/linkResolver.hpp" 40 #include "interpreter/oopMapCache.hpp" 41 #include "jvmtifiles/jvmtiEnv.hpp" 42 #include "logging/log.hpp" 43 #include "logging/logConfiguration.hpp" 44 #include "memory/metaspaceShared.hpp" 45 #include "memory/oopFactory.hpp" 46 #include "memory/universe.inline.hpp" 47 #include "oops/instanceKlass.hpp" 48 #include "oops/objArrayOop.hpp" 49 #include "oops/oop.inline.hpp" 50 #include "oops/symbol.hpp" 51 #include "oops/verifyOopClosure.hpp" 52 #include "prims/jvm_misc.hpp" 53 #include "prims/jvmtiExport.hpp" 54 #include "prims/jvmtiThreadState.hpp" 55 #include "prims/privilegedStack.hpp" 56 #include "runtime/arguments.hpp" 57 #include "runtime/atomic.inline.hpp" 58 #include "runtime/biasedLocking.hpp" 59 #include "runtime/commandLineFlagConstraintList.hpp" 60 #include "runtime/commandLineFlagRangeList.hpp" 61 #include "runtime/deoptimization.hpp" 62 #include "runtime/fprofiler.hpp" 63 #include "runtime/frame.inline.hpp" 64 #include "runtime/globals.hpp" 65 #include "runtime/init.hpp" 66 #include "runtime/interfaceSupport.hpp" 67 #include "runtime/java.hpp" 68 #include "runtime/javaCalls.hpp" 69 #include "runtime/jniPeriodicChecker.hpp" 70 #include "runtime/logTimer.hpp" 71 #include "runtime/memprofiler.hpp" 72 #include "runtime/mutexLocker.hpp" 73 #include "runtime/objectMonitor.hpp" 74 #include "runtime/orderAccess.inline.hpp" 75 #include "runtime/osThread.hpp" 76 #include "runtime/safepoint.hpp" 77 #include "runtime/sharedRuntime.hpp" 78 #include "runtime/statSampler.hpp" 79 #include "runtime/stubRoutines.hpp" 80 #include "runtime/sweeper.hpp" 81 #include "runtime/task.hpp" 82 #include "runtime/thread.inline.hpp" 83 #include "runtime/threadCritical.hpp" 84 #include "runtime/vframe.hpp" 85 #include "runtime/vframeArray.hpp" 86 #include "runtime/vframe_hp.hpp" 87 #include "runtime/vmThread.hpp" 88 #include "runtime/vm_operations.hpp" 89 #include "runtime/vm_version.hpp" 90 #include "services/attachListener.hpp" 91 #include "services/management.hpp" 92 #include "services/memTracker.hpp" 93 #include "services/threadService.hpp" 94 #include "trace/traceMacros.hpp" 95 #include "trace/tracing.hpp" 96 #include "utilities/defaultStream.hpp" 97 #include "utilities/dtrace.hpp" 98 #include "utilities/events.hpp" 99 #include "utilities/macros.hpp" 100 #include "utilities/preserveException.hpp" 101 #if INCLUDE_ALL_GCS 102 #include "gc/cms/concurrentMarkSweepThread.hpp" 103 #include "gc/g1/concurrentMarkThread.inline.hpp" 104 #include "gc/parallel/pcTasks.hpp" 105 #endif // INCLUDE_ALL_GCS 106 #if INCLUDE_JVMCI 107 #include "jvmci/jvmciCompiler.hpp" 108 #include "jvmci/jvmciRuntime.hpp" 109 #endif 110 #ifdef COMPILER1 111 #include "c1/c1_Compiler.hpp" 112 #endif 113 #ifdef COMPILER2 114 #include "opto/c2compiler.hpp" 115 #include "opto/idealGraphPrinter.hpp" 116 #endif 117 #if INCLUDE_RTM_OPT 118 #include "runtime/rtmLocking.hpp" 119 #endif 120 121 #ifdef DTRACE_ENABLED 122 123 // Only bother with this argument setup if dtrace is available 124 125 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 126 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 127 128 #define DTRACE_THREAD_PROBE(probe, javathread) \ 129 { \ 130 ResourceMark rm(this); \ 131 int len = 0; \ 132 const char* name = (javathread)->get_thread_name(); \ 133 len = strlen(name); \ 134 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 135 (char *) name, len, \ 136 java_lang_Thread::thread_id((javathread)->threadObj()), \ 137 (uintptr_t) (javathread)->osthread()->thread_id(), \ 138 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 139 } 140 141 #else // ndef DTRACE_ENABLED 142 143 #define DTRACE_THREAD_PROBE(probe, javathread) 144 145 #endif // ndef DTRACE_ENABLED 146 147 #ifndef USE_LIBRARY_BASED_TLS_ONLY 148 // Current thread is maintained as a thread-local variable 149 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL; 150 #endif 151 152 // Class hierarchy 153 // - Thread 154 // - VMThread 155 // - WatcherThread 156 // - ConcurrentMarkSweepThread 157 // - JavaThread 158 // - CompilerThread 159 160 // ======= Thread ======== 161 // Support for forcing alignment of thread objects for biased locking 162 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 163 if (UseBiasedLocking) { 164 const int alignment = markOopDesc::biased_lock_alignment; 165 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 166 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 167 : AllocateHeap(aligned_size, flags, CURRENT_PC, 168 AllocFailStrategy::RETURN_NULL); 169 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 170 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 171 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 172 "JavaThread alignment code overflowed allocated storage"); 173 if (aligned_addr != real_malloc_addr) { 174 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 175 p2i(real_malloc_addr), 176 p2i(aligned_addr)); 177 } 178 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 179 return aligned_addr; 180 } else { 181 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 182 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 183 } 184 } 185 186 void Thread::operator delete(void* p) { 187 if (UseBiasedLocking) { 188 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 189 FreeHeap(real_malloc_addr); 190 } else { 191 FreeHeap(p); 192 } 193 } 194 195 196 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 197 // JavaThread 198 199 200 Thread::Thread() { 201 // stack and get_thread 202 set_stack_base(NULL); 203 set_stack_size(0); 204 set_self_raw_id(0); 205 set_lgrp_id(-1); 206 DEBUG_ONLY(clear_suspendible_thread();) 207 208 // allocated data structures 209 set_osthread(NULL); 210 set_resource_area(new (mtThread)ResourceArea()); 211 DEBUG_ONLY(_current_resource_mark = NULL;) 212 set_handle_area(new (mtThread) HandleArea(NULL)); 213 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 214 set_active_handles(NULL); 215 set_free_handle_block(NULL); 216 set_last_handle_mark(NULL); 217 218 // This initial value ==> never claimed. 219 _oops_do_parity = 0; 220 221 // the handle mark links itself to last_handle_mark 222 new HandleMark(this); 223 224 // plain initialization 225 debug_only(_owned_locks = NULL;) 226 debug_only(_allow_allocation_count = 0;) 227 NOT_PRODUCT(_allow_safepoint_count = 0;) 228 NOT_PRODUCT(_skip_gcalot = false;) 229 _jvmti_env_iteration_count = 0; 230 set_allocated_bytes(0); 231 _vm_operation_started_count = 0; 232 _vm_operation_completed_count = 0; 233 _current_pending_monitor = NULL; 234 _current_pending_monitor_is_from_java = true; 235 _current_waiting_monitor = NULL; 236 _num_nested_signal = 0; 237 omFreeList = NULL; 238 omFreeCount = 0; 239 omFreeProvision = 32; 240 omInUseList = NULL; 241 omInUseCount = 0; 242 243 #ifdef ASSERT 244 _visited_for_critical_count = false; 245 #endif 246 247 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, 248 Monitor::_safepoint_check_sometimes); 249 _suspend_flags = 0; 250 251 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 252 _hashStateX = os::random(); 253 _hashStateY = 842502087; 254 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 255 _hashStateW = 273326509; 256 257 _OnTrap = 0; 258 _schedctl = NULL; 259 _Stalled = 0; 260 _TypeTag = 0x2BAD; 261 262 // Many of the following fields are effectively final - immutable 263 // Note that nascent threads can't use the Native Monitor-Mutex 264 // construct until the _MutexEvent is initialized ... 265 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 266 // we might instead use a stack of ParkEvents that we could provision on-demand. 267 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 268 // and ::Release() 269 _ParkEvent = ParkEvent::Allocate(this); 270 _SleepEvent = ParkEvent::Allocate(this); 271 _MutexEvent = ParkEvent::Allocate(this); 272 _MuxEvent = ParkEvent::Allocate(this); 273 274 #ifdef CHECK_UNHANDLED_OOPS 275 if (CheckUnhandledOops) { 276 _unhandled_oops = new UnhandledOops(this); 277 } 278 #endif // CHECK_UNHANDLED_OOPS 279 #ifdef ASSERT 280 if (UseBiasedLocking) { 281 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 282 assert(this == _real_malloc_address || 283 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 284 "bug in forced alignment of thread objects"); 285 } 286 #endif // ASSERT 287 } 288 289 void Thread::initialize_thread_current() { 290 #ifndef USE_LIBRARY_BASED_TLS_ONLY 291 assert(_thr_current == NULL, "Thread::current already initialized"); 292 _thr_current = this; 293 #endif 294 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized"); 295 ThreadLocalStorage::set_thread(this); 296 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 297 } 298 299 void Thread::clear_thread_current() { 300 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 301 #ifndef USE_LIBRARY_BASED_TLS_ONLY 302 _thr_current = NULL; 303 #endif 304 ThreadLocalStorage::set_thread(NULL); 305 } 306 307 void Thread::record_stack_base_and_size() { 308 set_stack_base(os::current_stack_base()); 309 set_stack_size(os::current_stack_size()); 310 // CR 7190089: on Solaris, primordial thread's stack is adjusted 311 // in initialize_thread(). Without the adjustment, stack size is 312 // incorrect if stack is set to unlimited (ulimit -s unlimited). 313 // So far, only Solaris has real implementation of initialize_thread(). 314 // 315 // set up any platform-specific state. 316 os::initialize_thread(this); 317 318 // Set stack limits after thread is initialized. 319 if (is_Java_thread()) { 320 ((JavaThread*) this)->set_stack_overflow_limit(); 321 ((JavaThread*) this)->set_reserved_stack_activation(stack_base()); 322 } 323 #if INCLUDE_NMT 324 // record thread's native stack, stack grows downward 325 MemTracker::record_thread_stack(stack_end(), stack_size()); 326 #endif // INCLUDE_NMT 327 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: " 328 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).", 329 os::current_thread_id(), p2i(stack_base() - stack_size()), 330 p2i(stack_base()), stack_size()/1024); 331 } 332 333 334 Thread::~Thread() { 335 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 336 ObjectSynchronizer::omFlush(this); 337 338 EVENT_THREAD_DESTRUCT(this); 339 340 // stack_base can be NULL if the thread is never started or exited before 341 // record_stack_base_and_size called. Although, we would like to ensure 342 // that all started threads do call record_stack_base_and_size(), there is 343 // not proper way to enforce that. 344 #if INCLUDE_NMT 345 if (_stack_base != NULL) { 346 MemTracker::release_thread_stack(stack_end(), stack_size()); 347 #ifdef ASSERT 348 set_stack_base(NULL); 349 #endif 350 } 351 #endif // INCLUDE_NMT 352 353 // deallocate data structures 354 delete resource_area(); 355 // since the handle marks are using the handle area, we have to deallocated the root 356 // handle mark before deallocating the thread's handle area, 357 assert(last_handle_mark() != NULL, "check we have an element"); 358 delete last_handle_mark(); 359 assert(last_handle_mark() == NULL, "check we have reached the end"); 360 361 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 362 // We NULL out the fields for good hygiene. 363 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 364 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 365 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 366 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 367 368 delete handle_area(); 369 delete metadata_handles(); 370 371 // osthread() can be NULL, if creation of thread failed. 372 if (osthread() != NULL) os::free_thread(osthread()); 373 374 delete _SR_lock; 375 376 // clear Thread::current if thread is deleting itself. 377 // Needed to ensure JNI correctly detects non-attached threads. 378 if (this == Thread::current()) { 379 clear_thread_current(); 380 } 381 382 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 383 } 384 385 // NOTE: dummy function for assertion purpose. 386 void Thread::run() { 387 ShouldNotReachHere(); 388 } 389 390 #ifdef ASSERT 391 // Private method to check for dangling thread pointer 392 void check_for_dangling_thread_pointer(Thread *thread) { 393 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 394 "possibility of dangling Thread pointer"); 395 } 396 #endif 397 398 ThreadPriority Thread::get_priority(const Thread* const thread) { 399 ThreadPriority priority; 400 // Can return an error! 401 (void)os::get_priority(thread, priority); 402 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 403 return priority; 404 } 405 406 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 407 debug_only(check_for_dangling_thread_pointer(thread);) 408 // Can return an error! 409 (void)os::set_priority(thread, priority); 410 } 411 412 413 void Thread::start(Thread* thread) { 414 // Start is different from resume in that its safety is guaranteed by context or 415 // being called from a Java method synchronized on the Thread object. 416 if (!DisableStartThread) { 417 if (thread->is_Java_thread()) { 418 // Initialize the thread state to RUNNABLE before starting this thread. 419 // Can not set it after the thread started because we do not know the 420 // exact thread state at that time. It could be in MONITOR_WAIT or 421 // in SLEEPING or some other state. 422 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 423 java_lang_Thread::RUNNABLE); 424 } 425 os::start_thread(thread); 426 } 427 } 428 429 // Enqueue a VM_Operation to do the job for us - sometime later 430 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 431 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 432 VMThread::execute(vm_stop); 433 } 434 435 436 // Check if an external suspend request has completed (or has been 437 // cancelled). Returns true if the thread is externally suspended and 438 // false otherwise. 439 // 440 // The bits parameter returns information about the code path through 441 // the routine. Useful for debugging: 442 // 443 // set in is_ext_suspend_completed(): 444 // 0x00000001 - routine was entered 445 // 0x00000010 - routine return false at end 446 // 0x00000100 - thread exited (return false) 447 // 0x00000200 - suspend request cancelled (return false) 448 // 0x00000400 - thread suspended (return true) 449 // 0x00001000 - thread is in a suspend equivalent state (return true) 450 // 0x00002000 - thread is native and walkable (return true) 451 // 0x00004000 - thread is native_trans and walkable (needed retry) 452 // 453 // set in wait_for_ext_suspend_completion(): 454 // 0x00010000 - routine was entered 455 // 0x00020000 - suspend request cancelled before loop (return false) 456 // 0x00040000 - thread suspended before loop (return true) 457 // 0x00080000 - suspend request cancelled in loop (return false) 458 // 0x00100000 - thread suspended in loop (return true) 459 // 0x00200000 - suspend not completed during retry loop (return false) 460 461 // Helper class for tracing suspend wait debug bits. 462 // 463 // 0x00000100 indicates that the target thread exited before it could 464 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 465 // 0x00080000 each indicate a cancelled suspend request so they don't 466 // count as wait failures either. 467 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 468 469 class TraceSuspendDebugBits : public StackObj { 470 private: 471 JavaThread * jt; 472 bool is_wait; 473 bool called_by_wait; // meaningful when !is_wait 474 uint32_t * bits; 475 476 public: 477 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 478 uint32_t *_bits) { 479 jt = _jt; 480 is_wait = _is_wait; 481 called_by_wait = _called_by_wait; 482 bits = _bits; 483 } 484 485 ~TraceSuspendDebugBits() { 486 if (!is_wait) { 487 #if 1 488 // By default, don't trace bits for is_ext_suspend_completed() calls. 489 // That trace is very chatty. 490 return; 491 #else 492 if (!called_by_wait) { 493 // If tracing for is_ext_suspend_completed() is enabled, then only 494 // trace calls to it from wait_for_ext_suspend_completion() 495 return; 496 } 497 #endif 498 } 499 500 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 501 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 502 MutexLocker ml(Threads_lock); // needed for get_thread_name() 503 ResourceMark rm; 504 505 tty->print_cr( 506 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 507 jt->get_thread_name(), *bits); 508 509 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 510 } 511 } 512 } 513 }; 514 #undef DEBUG_FALSE_BITS 515 516 517 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 518 uint32_t *bits) { 519 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 520 521 bool did_trans_retry = false; // only do thread_in_native_trans retry once 522 bool do_trans_retry; // flag to force the retry 523 524 *bits |= 0x00000001; 525 526 do { 527 do_trans_retry = false; 528 529 if (is_exiting()) { 530 // Thread is in the process of exiting. This is always checked 531 // first to reduce the risk of dereferencing a freed JavaThread. 532 *bits |= 0x00000100; 533 return false; 534 } 535 536 if (!is_external_suspend()) { 537 // Suspend request is cancelled. This is always checked before 538 // is_ext_suspended() to reduce the risk of a rogue resume 539 // confusing the thread that made the suspend request. 540 *bits |= 0x00000200; 541 return false; 542 } 543 544 if (is_ext_suspended()) { 545 // thread is suspended 546 *bits |= 0x00000400; 547 return true; 548 } 549 550 // Now that we no longer do hard suspends of threads running 551 // native code, the target thread can be changing thread state 552 // while we are in this routine: 553 // 554 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 555 // 556 // We save a copy of the thread state as observed at this moment 557 // and make our decision about suspend completeness based on the 558 // copy. This closes the race where the thread state is seen as 559 // _thread_in_native_trans in the if-thread_blocked check, but is 560 // seen as _thread_blocked in if-thread_in_native_trans check. 561 JavaThreadState save_state = thread_state(); 562 563 if (save_state == _thread_blocked && is_suspend_equivalent()) { 564 // If the thread's state is _thread_blocked and this blocking 565 // condition is known to be equivalent to a suspend, then we can 566 // consider the thread to be externally suspended. This means that 567 // the code that sets _thread_blocked has been modified to do 568 // self-suspension if the blocking condition releases. We also 569 // used to check for CONDVAR_WAIT here, but that is now covered by 570 // the _thread_blocked with self-suspension check. 571 // 572 // Return true since we wouldn't be here unless there was still an 573 // external suspend request. 574 *bits |= 0x00001000; 575 return true; 576 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 577 // Threads running native code will self-suspend on native==>VM/Java 578 // transitions. If its stack is walkable (should always be the case 579 // unless this function is called before the actual java_suspend() 580 // call), then the wait is done. 581 *bits |= 0x00002000; 582 return true; 583 } else if (!called_by_wait && !did_trans_retry && 584 save_state == _thread_in_native_trans && 585 frame_anchor()->walkable()) { 586 // The thread is transitioning from thread_in_native to another 587 // thread state. check_safepoint_and_suspend_for_native_trans() 588 // will force the thread to self-suspend. If it hasn't gotten 589 // there yet we may have caught the thread in-between the native 590 // code check above and the self-suspend. Lucky us. If we were 591 // called by wait_for_ext_suspend_completion(), then it 592 // will be doing the retries so we don't have to. 593 // 594 // Since we use the saved thread state in the if-statement above, 595 // there is a chance that the thread has already transitioned to 596 // _thread_blocked by the time we get here. In that case, we will 597 // make a single unnecessary pass through the logic below. This 598 // doesn't hurt anything since we still do the trans retry. 599 600 *bits |= 0x00004000; 601 602 // Once the thread leaves thread_in_native_trans for another 603 // thread state, we break out of this retry loop. We shouldn't 604 // need this flag to prevent us from getting back here, but 605 // sometimes paranoia is good. 606 did_trans_retry = true; 607 608 // We wait for the thread to transition to a more usable state. 609 for (int i = 1; i <= SuspendRetryCount; i++) { 610 // We used to do an "os::yield_all(i)" call here with the intention 611 // that yielding would increase on each retry. However, the parameter 612 // is ignored on Linux which means the yield didn't scale up. Waiting 613 // on the SR_lock below provides a much more predictable scale up for 614 // the delay. It also provides a simple/direct point to check for any 615 // safepoint requests from the VMThread 616 617 // temporarily drops SR_lock while doing wait with safepoint check 618 // (if we're a JavaThread - the WatcherThread can also call this) 619 // and increase delay with each retry 620 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 621 622 // check the actual thread state instead of what we saved above 623 if (thread_state() != _thread_in_native_trans) { 624 // the thread has transitioned to another thread state so 625 // try all the checks (except this one) one more time. 626 do_trans_retry = true; 627 break; 628 } 629 } // end retry loop 630 631 632 } 633 } while (do_trans_retry); 634 635 *bits |= 0x00000010; 636 return false; 637 } 638 639 // Wait for an external suspend request to complete (or be cancelled). 640 // Returns true if the thread is externally suspended and false otherwise. 641 // 642 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 643 uint32_t *bits) { 644 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 645 false /* !called_by_wait */, bits); 646 647 // local flag copies to minimize SR_lock hold time 648 bool is_suspended; 649 bool pending; 650 uint32_t reset_bits; 651 652 // set a marker so is_ext_suspend_completed() knows we are the caller 653 *bits |= 0x00010000; 654 655 // We use reset_bits to reinitialize the bits value at the top of 656 // each retry loop. This allows the caller to make use of any 657 // unused bits for their own marking purposes. 658 reset_bits = *bits; 659 660 { 661 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 662 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 663 delay, bits); 664 pending = is_external_suspend(); 665 } 666 // must release SR_lock to allow suspension to complete 667 668 if (!pending) { 669 // A cancelled suspend request is the only false return from 670 // is_ext_suspend_completed() that keeps us from entering the 671 // retry loop. 672 *bits |= 0x00020000; 673 return false; 674 } 675 676 if (is_suspended) { 677 *bits |= 0x00040000; 678 return true; 679 } 680 681 for (int i = 1; i <= retries; i++) { 682 *bits = reset_bits; // reinit to only track last retry 683 684 // We used to do an "os::yield_all(i)" call here with the intention 685 // that yielding would increase on each retry. However, the parameter 686 // is ignored on Linux which means the yield didn't scale up. Waiting 687 // on the SR_lock below provides a much more predictable scale up for 688 // the delay. It also provides a simple/direct point to check for any 689 // safepoint requests from the VMThread 690 691 { 692 MutexLocker ml(SR_lock()); 693 // wait with safepoint check (if we're a JavaThread - the WatcherThread 694 // can also call this) and increase delay with each retry 695 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 696 697 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 698 delay, bits); 699 700 // It is possible for the external suspend request to be cancelled 701 // (by a resume) before the actual suspend operation is completed. 702 // Refresh our local copy to see if we still need to wait. 703 pending = is_external_suspend(); 704 } 705 706 if (!pending) { 707 // A cancelled suspend request is the only false return from 708 // is_ext_suspend_completed() that keeps us from staying in the 709 // retry loop. 710 *bits |= 0x00080000; 711 return false; 712 } 713 714 if (is_suspended) { 715 *bits |= 0x00100000; 716 return true; 717 } 718 } // end retry loop 719 720 // thread did not suspend after all our retries 721 *bits |= 0x00200000; 722 return false; 723 } 724 725 #ifndef PRODUCT 726 void JavaThread::record_jump(address target, address instr, const char* file, 727 int line) { 728 729 // This should not need to be atomic as the only way for simultaneous 730 // updates is via interrupts. Even then this should be rare or non-existent 731 // and we don't care that much anyway. 732 733 int index = _jmp_ring_index; 734 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 735 _jmp_ring[index]._target = (intptr_t) target; 736 _jmp_ring[index]._instruction = (intptr_t) instr; 737 _jmp_ring[index]._file = file; 738 _jmp_ring[index]._line = line; 739 } 740 #endif // PRODUCT 741 742 // Called by flat profiler 743 // Callers have already called wait_for_ext_suspend_completion 744 // The assertion for that is currently too complex to put here: 745 bool JavaThread::profile_last_Java_frame(frame* _fr) { 746 bool gotframe = false; 747 // self suspension saves needed state. 748 if (has_last_Java_frame() && _anchor.walkable()) { 749 *_fr = pd_last_frame(); 750 gotframe = true; 751 } 752 return gotframe; 753 } 754 755 void Thread::interrupt(Thread* thread) { 756 debug_only(check_for_dangling_thread_pointer(thread);) 757 os::interrupt(thread); 758 } 759 760 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 761 debug_only(check_for_dangling_thread_pointer(thread);) 762 // Note: If clear_interrupted==false, this simply fetches and 763 // returns the value of the field osthread()->interrupted(). 764 return os::is_interrupted(thread, clear_interrupted); 765 } 766 767 768 // GC Support 769 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 770 jint thread_parity = _oops_do_parity; 771 if (thread_parity != strong_roots_parity) { 772 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 773 if (res == thread_parity) { 774 return true; 775 } else { 776 guarantee(res == strong_roots_parity, "Or else what?"); 777 return false; 778 } 779 } 780 return false; 781 } 782 783 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 784 active_handles()->oops_do(f); 785 // Do oop for ThreadShadow 786 f->do_oop((oop*)&_pending_exception); 787 handle_area()->oops_do(f); 788 } 789 790 void Thread::nmethods_do(CodeBlobClosure* cf) { 791 // no nmethods in a generic thread... 792 } 793 794 void Thread::metadata_handles_do(void f(Metadata*)) { 795 // Only walk the Handles in Thread. 796 if (metadata_handles() != NULL) { 797 for (int i = 0; i< metadata_handles()->length(); i++) { 798 f(metadata_handles()->at(i)); 799 } 800 } 801 } 802 803 void Thread::print_on(outputStream* st) const { 804 // get_priority assumes osthread initialized 805 if (osthread() != NULL) { 806 int os_prio; 807 if (os::get_native_priority(this, &os_prio) == OS_OK) { 808 st->print("os_prio=%d ", os_prio); 809 } 810 st->print("tid=" INTPTR_FORMAT " ", p2i(this)); 811 ext().print_on(st); 812 osthread()->print_on(st); 813 } 814 debug_only(if (WizardMode) print_owned_locks_on(st);) 815 } 816 817 // Thread::print_on_error() is called by fatal error handler. Don't use 818 // any lock or allocate memory. 819 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 820 if (is_VM_thread()) st->print("VMThread"); 821 else if (is_Compiler_thread()) st->print("CompilerThread"); 822 else if (is_Java_thread()) st->print("JavaThread"); 823 else if (is_GC_task_thread()) st->print("GCTaskThread"); 824 else if (is_Watcher_thread()) st->print("WatcherThread"); 825 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 826 else st->print("Thread"); 827 828 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 829 p2i(stack_end()), p2i(stack_base())); 830 831 if (osthread()) { 832 st->print(" [id=%d]", osthread()->thread_id()); 833 } 834 } 835 836 #ifdef ASSERT 837 void Thread::print_owned_locks_on(outputStream* st) const { 838 Monitor *cur = _owned_locks; 839 if (cur == NULL) { 840 st->print(" (no locks) "); 841 } else { 842 st->print_cr(" Locks owned:"); 843 while (cur) { 844 cur->print_on(st); 845 cur = cur->next(); 846 } 847 } 848 } 849 850 static int ref_use_count = 0; 851 852 bool Thread::owns_locks_but_compiled_lock() const { 853 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 854 if (cur != Compile_lock) return true; 855 } 856 return false; 857 } 858 859 860 #endif 861 862 #ifndef PRODUCT 863 864 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 865 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 866 // no threads which allow_vm_block's are held 867 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 868 // Check if current thread is allowed to block at a safepoint 869 if (!(_allow_safepoint_count == 0)) { 870 fatal("Possible safepoint reached by thread that does not allow it"); 871 } 872 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 873 fatal("LEAF method calling lock?"); 874 } 875 876 #ifdef ASSERT 877 if (potential_vm_operation && is_Java_thread() 878 && !Universe::is_bootstrapping()) { 879 // Make sure we do not hold any locks that the VM thread also uses. 880 // This could potentially lead to deadlocks 881 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 882 // Threads_lock is special, since the safepoint synchronization will not start before this is 883 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 884 // since it is used to transfer control between JavaThreads and the VMThread 885 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 886 if ((cur->allow_vm_block() && 887 cur != Threads_lock && 888 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 889 cur != VMOperationRequest_lock && 890 cur != VMOperationQueue_lock) || 891 cur->rank() == Mutex::special) { 892 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 893 } 894 } 895 } 896 897 if (GCALotAtAllSafepoints) { 898 // We could enter a safepoint here and thus have a gc 899 InterfaceSupport::check_gc_alot(); 900 } 901 #endif 902 } 903 #endif 904 905 bool Thread::is_in_stack(address adr) const { 906 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 907 address end = os::current_stack_pointer(); 908 // Allow non Java threads to call this without stack_base 909 if (_stack_base == NULL) return true; 910 if (stack_base() >= adr && adr >= end) return true; 911 912 return false; 913 } 914 915 bool Thread::is_in_usable_stack(address adr) const { 916 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0; 917 size_t usable_stack_size = _stack_size - stack_guard_size; 918 919 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 920 } 921 922 923 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 924 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 925 // used for compilation in the future. If that change is made, the need for these methods 926 // should be revisited, and they should be removed if possible. 927 928 bool Thread::is_lock_owned(address adr) const { 929 return on_local_stack(adr); 930 } 931 932 bool Thread::set_as_starting_thread() { 933 // NOTE: this must be called inside the main thread. 934 return os::create_main_thread((JavaThread*)this); 935 } 936 937 static void initialize_class(Symbol* class_name, TRAPS) { 938 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 939 InstanceKlass::cast(klass)->initialize(CHECK); 940 } 941 942 943 // Creates the initial ThreadGroup 944 static Handle create_initial_thread_group(TRAPS) { 945 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 946 instanceKlassHandle klass (THREAD, k); 947 948 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 949 { 950 JavaValue result(T_VOID); 951 JavaCalls::call_special(&result, 952 system_instance, 953 klass, 954 vmSymbols::object_initializer_name(), 955 vmSymbols::void_method_signature(), 956 CHECK_NH); 957 } 958 Universe::set_system_thread_group(system_instance()); 959 960 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 961 { 962 JavaValue result(T_VOID); 963 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 964 JavaCalls::call_special(&result, 965 main_instance, 966 klass, 967 vmSymbols::object_initializer_name(), 968 vmSymbols::threadgroup_string_void_signature(), 969 system_instance, 970 string, 971 CHECK_NH); 972 } 973 return main_instance; 974 } 975 976 // Creates the initial Thread 977 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 978 TRAPS) { 979 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 980 instanceKlassHandle klass (THREAD, k); 981 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 982 983 java_lang_Thread::set_thread(thread_oop(), thread); 984 java_lang_Thread::set_priority(thread_oop(), NormPriority); 985 thread->set_threadObj(thread_oop()); 986 987 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 988 989 JavaValue result(T_VOID); 990 JavaCalls::call_special(&result, thread_oop, 991 klass, 992 vmSymbols::object_initializer_name(), 993 vmSymbols::threadgroup_string_void_signature(), 994 thread_group, 995 string, 996 CHECK_NULL); 997 return thread_oop(); 998 } 999 1000 static void call_initializeSystemClass(TRAPS) { 1001 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1002 instanceKlassHandle klass (THREAD, k); 1003 1004 JavaValue result(T_VOID); 1005 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1006 vmSymbols::void_method_signature(), CHECK); 1007 } 1008 1009 char java_runtime_name[128] = ""; 1010 char java_runtime_version[128] = ""; 1011 1012 // extract the JRE name from java.lang.VersionProps.java_runtime_name 1013 static const char* get_java_runtime_name(TRAPS) { 1014 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1015 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1016 fieldDescriptor fd; 1017 bool found = k != NULL && 1018 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1019 vmSymbols::string_signature(), &fd); 1020 if (found) { 1021 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1022 if (name_oop == NULL) { 1023 return NULL; 1024 } 1025 const char* name = java_lang_String::as_utf8_string(name_oop, 1026 java_runtime_name, 1027 sizeof(java_runtime_name)); 1028 return name; 1029 } else { 1030 return NULL; 1031 } 1032 } 1033 1034 // extract the JRE version from java.lang.VersionProps.java_runtime_version 1035 static const char* get_java_runtime_version(TRAPS) { 1036 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1037 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1038 fieldDescriptor fd; 1039 bool found = k != NULL && 1040 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1041 vmSymbols::string_signature(), &fd); 1042 if (found) { 1043 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1044 if (name_oop == NULL) { 1045 return NULL; 1046 } 1047 const char* name = java_lang_String::as_utf8_string(name_oop, 1048 java_runtime_version, 1049 sizeof(java_runtime_version)); 1050 return name; 1051 } else { 1052 return NULL; 1053 } 1054 } 1055 1056 // General purpose hook into Java code, run once when the VM is initialized. 1057 // The Java library method itself may be changed independently from the VM. 1058 static void call_postVMInitHook(TRAPS) { 1059 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1060 instanceKlassHandle klass (THREAD, k); 1061 if (klass.not_null()) { 1062 JavaValue result(T_VOID); 1063 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1064 vmSymbols::void_method_signature(), 1065 CHECK); 1066 } 1067 } 1068 1069 static void reset_vm_info_property(TRAPS) { 1070 // the vm info string 1071 ResourceMark rm(THREAD); 1072 const char *vm_info = VM_Version::vm_info_string(); 1073 1074 // java.lang.System class 1075 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1076 instanceKlassHandle klass (THREAD, k); 1077 1078 // setProperty arguments 1079 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1080 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1081 1082 // return value 1083 JavaValue r(T_OBJECT); 1084 1085 // public static String setProperty(String key, String value); 1086 JavaCalls::call_static(&r, 1087 klass, 1088 vmSymbols::setProperty_name(), 1089 vmSymbols::string_string_string_signature(), 1090 key_str, 1091 value_str, 1092 CHECK); 1093 } 1094 1095 1096 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 1097 bool daemon, TRAPS) { 1098 assert(thread_group.not_null(), "thread group should be specified"); 1099 assert(threadObj() == NULL, "should only create Java thread object once"); 1100 1101 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1102 instanceKlassHandle klass (THREAD, k); 1103 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1104 1105 java_lang_Thread::set_thread(thread_oop(), this); 1106 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1107 set_threadObj(thread_oop()); 1108 1109 JavaValue result(T_VOID); 1110 if (thread_name != NULL) { 1111 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1112 // Thread gets assigned specified name and null target 1113 JavaCalls::call_special(&result, 1114 thread_oop, 1115 klass, 1116 vmSymbols::object_initializer_name(), 1117 vmSymbols::threadgroup_string_void_signature(), 1118 thread_group, // Argument 1 1119 name, // Argument 2 1120 THREAD); 1121 } else { 1122 // Thread gets assigned name "Thread-nnn" and null target 1123 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1124 JavaCalls::call_special(&result, 1125 thread_oop, 1126 klass, 1127 vmSymbols::object_initializer_name(), 1128 vmSymbols::threadgroup_runnable_void_signature(), 1129 thread_group, // Argument 1 1130 Handle(), // Argument 2 1131 THREAD); 1132 } 1133 1134 1135 if (daemon) { 1136 java_lang_Thread::set_daemon(thread_oop()); 1137 } 1138 1139 if (HAS_PENDING_EXCEPTION) { 1140 return; 1141 } 1142 1143 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass()); 1144 Handle threadObj(THREAD, this->threadObj()); 1145 1146 JavaCalls::call_special(&result, 1147 thread_group, 1148 group, 1149 vmSymbols::add_method_name(), 1150 vmSymbols::thread_void_signature(), 1151 threadObj, // Arg 1 1152 THREAD); 1153 } 1154 1155 // NamedThread -- non-JavaThread subclasses with multiple 1156 // uniquely named instances should derive from this. 1157 NamedThread::NamedThread() : Thread() { 1158 _name = NULL; 1159 _processed_thread = NULL; 1160 _gc_id = GCId::undefined(); 1161 } 1162 1163 NamedThread::~NamedThread() { 1164 if (_name != NULL) { 1165 FREE_C_HEAP_ARRAY(char, _name); 1166 _name = NULL; 1167 } 1168 } 1169 1170 void NamedThread::set_name(const char* format, ...) { 1171 guarantee(_name == NULL, "Only get to set name once."); 1172 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1173 guarantee(_name != NULL, "alloc failure"); 1174 va_list ap; 1175 va_start(ap, format); 1176 jio_vsnprintf(_name, max_name_len, format, ap); 1177 va_end(ap); 1178 } 1179 1180 void NamedThread::initialize_named_thread() { 1181 set_native_thread_name(name()); 1182 } 1183 1184 void NamedThread::print_on(outputStream* st) const { 1185 st->print("\"%s\" ", name()); 1186 Thread::print_on(st); 1187 st->cr(); 1188 } 1189 1190 1191 // ======= WatcherThread ======== 1192 1193 // The watcher thread exists to simulate timer interrupts. It should 1194 // be replaced by an abstraction over whatever native support for 1195 // timer interrupts exists on the platform. 1196 1197 WatcherThread* WatcherThread::_watcher_thread = NULL; 1198 bool WatcherThread::_startable = false; 1199 volatile bool WatcherThread::_should_terminate = false; 1200 1201 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1202 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1203 if (os::create_thread(this, os::watcher_thread)) { 1204 _watcher_thread = this; 1205 1206 // Set the watcher thread to the highest OS priority which should not be 1207 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1208 // is created. The only normal thread using this priority is the reference 1209 // handler thread, which runs for very short intervals only. 1210 // If the VMThread's priority is not lower than the WatcherThread profiling 1211 // will be inaccurate. 1212 os::set_priority(this, MaxPriority); 1213 if (!DisableStartThread) { 1214 os::start_thread(this); 1215 } 1216 } 1217 } 1218 1219 int WatcherThread::sleep() const { 1220 // The WatcherThread does not participate in the safepoint protocol 1221 // for the PeriodicTask_lock because it is not a JavaThread. 1222 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1223 1224 if (_should_terminate) { 1225 // check for termination before we do any housekeeping or wait 1226 return 0; // we did not sleep. 1227 } 1228 1229 // remaining will be zero if there are no tasks, 1230 // causing the WatcherThread to sleep until a task is 1231 // enrolled 1232 int remaining = PeriodicTask::time_to_wait(); 1233 int time_slept = 0; 1234 1235 // we expect this to timeout - we only ever get unparked when 1236 // we should terminate or when a new task has been enrolled 1237 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1238 1239 jlong time_before_loop = os::javaTimeNanos(); 1240 1241 while (true) { 1242 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, 1243 remaining); 1244 jlong now = os::javaTimeNanos(); 1245 1246 if (remaining == 0) { 1247 // if we didn't have any tasks we could have waited for a long time 1248 // consider the time_slept zero and reset time_before_loop 1249 time_slept = 0; 1250 time_before_loop = now; 1251 } else { 1252 // need to recalculate since we might have new tasks in _tasks 1253 time_slept = (int) ((now - time_before_loop) / 1000000); 1254 } 1255 1256 // Change to task list or spurious wakeup of some kind 1257 if (timedout || _should_terminate) { 1258 break; 1259 } 1260 1261 remaining = PeriodicTask::time_to_wait(); 1262 if (remaining == 0) { 1263 // Last task was just disenrolled so loop around and wait until 1264 // another task gets enrolled 1265 continue; 1266 } 1267 1268 remaining -= time_slept; 1269 if (remaining <= 0) { 1270 break; 1271 } 1272 } 1273 1274 return time_slept; 1275 } 1276 1277 void WatcherThread::run() { 1278 assert(this == watcher_thread(), "just checking"); 1279 1280 this->record_stack_base_and_size(); 1281 this->set_native_thread_name(this->name()); 1282 this->set_active_handles(JNIHandleBlock::allocate_block()); 1283 while (true) { 1284 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1285 assert(watcher_thread() == this, "thread consistency check"); 1286 1287 // Calculate how long it'll be until the next PeriodicTask work 1288 // should be done, and sleep that amount of time. 1289 int time_waited = sleep(); 1290 1291 if (is_error_reported()) { 1292 // A fatal error has happened, the error handler(VMError::report_and_die) 1293 // should abort JVM after creating an error log file. However in some 1294 // rare cases, the error handler itself might deadlock. Here we try to 1295 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1296 // 1297 // This code is in WatcherThread because WatcherThread wakes up 1298 // periodically so the fatal error handler doesn't need to do anything; 1299 // also because the WatcherThread is less likely to crash than other 1300 // threads. 1301 1302 for (;;) { 1303 if (!ShowMessageBoxOnError 1304 && (OnError == NULL || OnError[0] == '\0') 1305 && Arguments::abort_hook() == NULL) { 1306 os::sleep(this, (jlong)ErrorLogTimeout * 1000, false); // in seconds 1307 fdStream err(defaultStream::output_fd()); 1308 err.print_raw_cr("# [ timer expired, abort... ]"); 1309 // skip atexit/vm_exit/vm_abort hooks 1310 os::die(); 1311 } 1312 1313 // Wake up 5 seconds later, the fatal handler may reset OnError or 1314 // ShowMessageBoxOnError when it is ready to abort. 1315 os::sleep(this, 5 * 1000, false); 1316 } 1317 } 1318 1319 if (_should_terminate) { 1320 // check for termination before posting the next tick 1321 break; 1322 } 1323 1324 PeriodicTask::real_time_tick(time_waited); 1325 } 1326 1327 // Signal that it is terminated 1328 { 1329 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1330 _watcher_thread = NULL; 1331 Terminator_lock->notify(); 1332 } 1333 } 1334 1335 void WatcherThread::start() { 1336 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1337 1338 if (watcher_thread() == NULL && _startable) { 1339 _should_terminate = false; 1340 // Create the single instance of WatcherThread 1341 new WatcherThread(); 1342 } 1343 } 1344 1345 void WatcherThread::make_startable() { 1346 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1347 _startable = true; 1348 } 1349 1350 void WatcherThread::stop() { 1351 { 1352 // Follow normal safepoint aware lock enter protocol since the 1353 // WatcherThread is stopped by another JavaThread. 1354 MutexLocker ml(PeriodicTask_lock); 1355 _should_terminate = true; 1356 1357 WatcherThread* watcher = watcher_thread(); 1358 if (watcher != NULL) { 1359 // unpark the WatcherThread so it can see that it should terminate 1360 watcher->unpark(); 1361 } 1362 } 1363 1364 MutexLocker mu(Terminator_lock); 1365 1366 while (watcher_thread() != NULL) { 1367 // This wait should make safepoint checks, wait without a timeout, 1368 // and wait as a suspend-equivalent condition. 1369 // 1370 // Note: If the FlatProfiler is running, then this thread is waiting 1371 // for the WatcherThread to terminate and the WatcherThread, via the 1372 // FlatProfiler task, is waiting for the external suspend request on 1373 // this thread to complete. wait_for_ext_suspend_completion() will 1374 // eventually timeout, but that takes time. Making this wait a 1375 // suspend-equivalent condition solves that timeout problem. 1376 // 1377 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1378 Mutex::_as_suspend_equivalent_flag); 1379 } 1380 } 1381 1382 void WatcherThread::unpark() { 1383 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1384 PeriodicTask_lock->notify(); 1385 } 1386 1387 void WatcherThread::print_on(outputStream* st) const { 1388 st->print("\"%s\" ", name()); 1389 Thread::print_on(st); 1390 st->cr(); 1391 } 1392 1393 // ======= JavaThread ======== 1394 1395 #if INCLUDE_JVMCI 1396 1397 jlong* JavaThread::_jvmci_old_thread_counters; 1398 1399 bool jvmci_counters_include(JavaThread* thread) { 1400 oop threadObj = thread->threadObj(); 1401 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); 1402 } 1403 1404 void JavaThread::collect_counters(typeArrayOop array) { 1405 if (JVMCICounterSize > 0) { 1406 MutexLocker tl(Threads_lock); 1407 for (int i = 0; i < array->length(); i++) { 1408 array->long_at_put(i, _jvmci_old_thread_counters[i]); 1409 } 1410 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) { 1411 if (jvmci_counters_include(tp)) { 1412 for (int i = 0; i < array->length(); i++) { 1413 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]); 1414 } 1415 } 1416 } 1417 } 1418 } 1419 1420 #endif // INCLUDE_JVMCI 1421 1422 // A JavaThread is a normal Java thread 1423 1424 void JavaThread::initialize() { 1425 // Initialize fields 1426 1427 set_saved_exception_pc(NULL); 1428 set_threadObj(NULL); 1429 _anchor.clear(); 1430 set_entry_point(NULL); 1431 set_jni_functions(jni_functions()); 1432 set_callee_target(NULL); 1433 set_vm_result(NULL); 1434 set_vm_result_2(NULL); 1435 set_vframe_array_head(NULL); 1436 set_vframe_array_last(NULL); 1437 set_deferred_locals(NULL); 1438 set_deopt_mark(NULL); 1439 set_deopt_nmethod(NULL); 1440 clear_must_deopt_id(); 1441 set_monitor_chunks(NULL); 1442 set_next(NULL); 1443 set_thread_state(_thread_new); 1444 _terminated = _not_terminated; 1445 _privileged_stack_top = NULL; 1446 _array_for_gc = NULL; 1447 _suspend_equivalent = false; 1448 _in_deopt_handler = 0; 1449 _doing_unsafe_access = false; 1450 _stack_guard_state = stack_guard_unused; 1451 #if INCLUDE_JVMCI 1452 _pending_monitorenter = false; 1453 _pending_deoptimization = -1; 1454 _pending_failed_speculation = NULL; 1455 _pending_transfer_to_interpreter = false; 1456 _jvmci._alternate_call_target = NULL; 1457 assert(_jvmci._implicit_exception_pc == NULL, "must be"); 1458 if (JVMCICounterSize > 0) { 1459 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 1460 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize); 1461 } else { 1462 _jvmci_counters = NULL; 1463 } 1464 #endif // INCLUDE_JVMCI 1465 _reserved_stack_activation = NULL; // stack base not known yet 1466 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1467 _exception_pc = 0; 1468 _exception_handler_pc = 0; 1469 _is_method_handle_return = 0; 1470 _jvmti_thread_state= NULL; 1471 _should_post_on_exceptions_flag = JNI_FALSE; 1472 _jvmti_get_loaded_classes_closure = NULL; 1473 _interp_only_mode = 0; 1474 _special_runtime_exit_condition = _no_async_condition; 1475 _pending_async_exception = NULL; 1476 _thread_stat = NULL; 1477 _thread_stat = new ThreadStatistics(); 1478 _blocked_on_compilation = false; 1479 _jni_active_critical = 0; 1480 _pending_jni_exception_check_fn = NULL; 1481 _do_not_unlock_if_synchronized = false; 1482 _cached_monitor_info = NULL; 1483 _parker = Parker::Allocate(this); 1484 1485 #ifndef PRODUCT 1486 _jmp_ring_index = 0; 1487 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1488 record_jump(NULL, NULL, NULL, 0); 1489 } 1490 #endif // PRODUCT 1491 1492 set_thread_profiler(NULL); 1493 if (FlatProfiler::is_active()) { 1494 // This is where we would decide to either give each thread it's own profiler 1495 // or use one global one from FlatProfiler, 1496 // or up to some count of the number of profiled threads, etc. 1497 ThreadProfiler* pp = new ThreadProfiler(); 1498 pp->engage(); 1499 set_thread_profiler(pp); 1500 } 1501 1502 // Setup safepoint state info for this thread 1503 ThreadSafepointState::create(this); 1504 1505 debug_only(_java_call_counter = 0); 1506 1507 // JVMTI PopFrame support 1508 _popframe_condition = popframe_inactive; 1509 _popframe_preserved_args = NULL; 1510 _popframe_preserved_args_size = 0; 1511 _frames_to_pop_failed_realloc = 0; 1512 1513 pd_initialize(); 1514 } 1515 1516 #if INCLUDE_ALL_GCS 1517 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1518 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1519 #endif // INCLUDE_ALL_GCS 1520 1521 JavaThread::JavaThread(bool is_attaching_via_jni) : 1522 Thread() 1523 #if INCLUDE_ALL_GCS 1524 , _satb_mark_queue(&_satb_mark_queue_set), 1525 _dirty_card_queue(&_dirty_card_queue_set) 1526 #endif // INCLUDE_ALL_GCS 1527 { 1528 initialize(); 1529 if (is_attaching_via_jni) { 1530 _jni_attach_state = _attaching_via_jni; 1531 } else { 1532 _jni_attach_state = _not_attaching_via_jni; 1533 } 1534 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1535 } 1536 1537 bool JavaThread::reguard_stack(address cur_sp) { 1538 if (_stack_guard_state != stack_guard_yellow_reserved_disabled 1539 && _stack_guard_state != stack_guard_reserved_disabled) { 1540 return true; // Stack already guarded or guard pages not needed. 1541 } 1542 1543 if (register_stack_overflow()) { 1544 // For those architectures which have separate register and 1545 // memory stacks, we must check the register stack to see if 1546 // it has overflowed. 1547 return false; 1548 } 1549 1550 // Java code never executes within the yellow zone: the latter is only 1551 // there to provoke an exception during stack banging. If java code 1552 // is executing there, either StackShadowPages should be larger, or 1553 // some exception code in c1, c2 or the interpreter isn't unwinding 1554 // when it should. 1555 guarantee(cur_sp > stack_reserved_zone_base(), 1556 "not enough space to reguard - increase StackShadowPages"); 1557 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) { 1558 enable_stack_yellow_reserved_zone(); 1559 if (reserved_stack_activation() != stack_base()) { 1560 set_reserved_stack_activation(stack_base()); 1561 } 1562 } else if (_stack_guard_state == stack_guard_reserved_disabled) { 1563 set_reserved_stack_activation(stack_base()); 1564 enable_stack_reserved_zone(); 1565 } 1566 return true; 1567 } 1568 1569 bool JavaThread::reguard_stack(void) { 1570 return reguard_stack(os::current_stack_pointer()); 1571 } 1572 1573 1574 void JavaThread::block_if_vm_exited() { 1575 if (_terminated == _vm_exited) { 1576 // _vm_exited is set at safepoint, and Threads_lock is never released 1577 // we will block here forever 1578 Threads_lock->lock_without_safepoint_check(); 1579 ShouldNotReachHere(); 1580 } 1581 } 1582 1583 1584 // Remove this ifdef when C1 is ported to the compiler interface. 1585 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1586 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1587 1588 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1589 Thread() 1590 #if INCLUDE_ALL_GCS 1591 , _satb_mark_queue(&_satb_mark_queue_set), 1592 _dirty_card_queue(&_dirty_card_queue_set) 1593 #endif // INCLUDE_ALL_GCS 1594 { 1595 initialize(); 1596 _jni_attach_state = _not_attaching_via_jni; 1597 set_entry_point(entry_point); 1598 // Create the native thread itself. 1599 // %note runtime_23 1600 os::ThreadType thr_type = os::java_thread; 1601 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1602 os::java_thread; 1603 os::create_thread(this, thr_type, stack_sz); 1604 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1605 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1606 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1607 // the exception consists of creating the exception object & initializing it, initialization 1608 // will leave the VM via a JavaCall and then all locks must be unlocked). 1609 // 1610 // The thread is still suspended when we reach here. Thread must be explicit started 1611 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1612 // by calling Threads:add. The reason why this is not done here, is because the thread 1613 // object must be fully initialized (take a look at JVM_Start) 1614 } 1615 1616 JavaThread::~JavaThread() { 1617 1618 // JSR166 -- return the parker to the free list 1619 Parker::Release(_parker); 1620 _parker = NULL; 1621 1622 // Free any remaining previous UnrollBlock 1623 vframeArray* old_array = vframe_array_last(); 1624 1625 if (old_array != NULL) { 1626 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1627 old_array->set_unroll_block(NULL); 1628 delete old_info; 1629 delete old_array; 1630 } 1631 1632 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1633 if (deferred != NULL) { 1634 // This can only happen if thread is destroyed before deoptimization occurs. 1635 assert(deferred->length() != 0, "empty array!"); 1636 do { 1637 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1638 deferred->remove_at(0); 1639 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1640 delete dlv; 1641 } while (deferred->length() != 0); 1642 delete deferred; 1643 } 1644 1645 // All Java related clean up happens in exit 1646 ThreadSafepointState::destroy(this); 1647 if (_thread_profiler != NULL) delete _thread_profiler; 1648 if (_thread_stat != NULL) delete _thread_stat; 1649 1650 #if INCLUDE_JVMCI 1651 if (JVMCICounterSize > 0) { 1652 if (jvmci_counters_include(this)) { 1653 for (int i = 0; i < JVMCICounterSize; i++) { 1654 _jvmci_old_thread_counters[i] += _jvmci_counters[i]; 1655 } 1656 } 1657 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); 1658 } 1659 #endif // INCLUDE_JVMCI 1660 } 1661 1662 1663 // The first routine called by a new Java thread 1664 void JavaThread::run() { 1665 // initialize thread-local alloc buffer related fields 1666 this->initialize_tlab(); 1667 1668 // used to test validity of stack trace backs 1669 this->record_base_of_stack_pointer(); 1670 1671 // Record real stack base and size. 1672 this->record_stack_base_and_size(); 1673 1674 this->create_stack_guard_pages(); 1675 1676 this->cache_global_variables(); 1677 1678 // Thread is now sufficient initialized to be handled by the safepoint code as being 1679 // in the VM. Change thread state from _thread_new to _thread_in_vm 1680 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1681 1682 assert(JavaThread::current() == this, "sanity check"); 1683 assert(!Thread::current()->owns_locks(), "sanity check"); 1684 1685 DTRACE_THREAD_PROBE(start, this); 1686 1687 // This operation might block. We call that after all safepoint checks for a new thread has 1688 // been completed. 1689 this->set_active_handles(JNIHandleBlock::allocate_block()); 1690 1691 if (JvmtiExport::should_post_thread_life()) { 1692 JvmtiExport::post_thread_start(this); 1693 } 1694 1695 EventThreadStart event; 1696 if (event.should_commit()) { 1697 event.set_thread(THREAD_TRACE_ID(this)); 1698 event.commit(); 1699 } 1700 1701 // We call another function to do the rest so we are sure that the stack addresses used 1702 // from there will be lower than the stack base just computed 1703 thread_main_inner(); 1704 1705 // Note, thread is no longer valid at this point! 1706 } 1707 1708 1709 void JavaThread::thread_main_inner() { 1710 assert(JavaThread::current() == this, "sanity check"); 1711 assert(this->threadObj() != NULL, "just checking"); 1712 1713 // Execute thread entry point unless this thread has a pending exception 1714 // or has been stopped before starting. 1715 // Note: Due to JVM_StopThread we can have pending exceptions already! 1716 if (!this->has_pending_exception() && 1717 !java_lang_Thread::is_stillborn(this->threadObj())) { 1718 { 1719 ResourceMark rm(this); 1720 this->set_native_thread_name(this->get_thread_name()); 1721 } 1722 HandleMark hm(this); 1723 this->entry_point()(this, this); 1724 } 1725 1726 DTRACE_THREAD_PROBE(stop, this); 1727 1728 this->exit(false); 1729 delete this; 1730 } 1731 1732 1733 static void ensure_join(JavaThread* thread) { 1734 // We do not need to grap the Threads_lock, since we are operating on ourself. 1735 Handle threadObj(thread, thread->threadObj()); 1736 assert(threadObj.not_null(), "java thread object must exist"); 1737 ObjectLocker lock(threadObj, thread); 1738 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1739 thread->clear_pending_exception(); 1740 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1741 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1742 // Clear the native thread instance - this makes isAlive return false and allows the join() 1743 // to complete once we've done the notify_all below 1744 java_lang_Thread::set_thread(threadObj(), NULL); 1745 lock.notify_all(thread); 1746 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1747 thread->clear_pending_exception(); 1748 } 1749 1750 1751 // For any new cleanup additions, please check to see if they need to be applied to 1752 // cleanup_failed_attach_current_thread as well. 1753 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1754 assert(this == JavaThread::current(), "thread consistency check"); 1755 1756 HandleMark hm(this); 1757 Handle uncaught_exception(this, this->pending_exception()); 1758 this->clear_pending_exception(); 1759 Handle threadObj(this, this->threadObj()); 1760 assert(threadObj.not_null(), "Java thread object should be created"); 1761 1762 if (get_thread_profiler() != NULL) { 1763 get_thread_profiler()->disengage(); 1764 ResourceMark rm; 1765 get_thread_profiler()->print(get_thread_name()); 1766 } 1767 1768 1769 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1770 { 1771 EXCEPTION_MARK; 1772 1773 CLEAR_PENDING_EXCEPTION; 1774 } 1775 if (!destroy_vm) { 1776 if (uncaught_exception.not_null()) { 1777 EXCEPTION_MARK; 1778 // Call method Thread.dispatchUncaughtException(). 1779 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1780 JavaValue result(T_VOID); 1781 JavaCalls::call_virtual(&result, 1782 threadObj, thread_klass, 1783 vmSymbols::dispatchUncaughtException_name(), 1784 vmSymbols::throwable_void_signature(), 1785 uncaught_exception, 1786 THREAD); 1787 if (HAS_PENDING_EXCEPTION) { 1788 ResourceMark rm(this); 1789 jio_fprintf(defaultStream::error_stream(), 1790 "\nException: %s thrown from the UncaughtExceptionHandler" 1791 " in thread \"%s\"\n", 1792 pending_exception()->klass()->external_name(), 1793 get_thread_name()); 1794 CLEAR_PENDING_EXCEPTION; 1795 } 1796 } 1797 1798 // Called before the java thread exit since we want to read info 1799 // from java_lang_Thread object 1800 EventThreadEnd event; 1801 if (event.should_commit()) { 1802 event.set_thread(THREAD_TRACE_ID(this)); 1803 event.commit(); 1804 } 1805 1806 // Call after last event on thread 1807 EVENT_THREAD_EXIT(this); 1808 1809 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1810 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1811 // is deprecated anyhow. 1812 if (!is_Compiler_thread()) { 1813 int count = 3; 1814 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1815 EXCEPTION_MARK; 1816 JavaValue result(T_VOID); 1817 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1818 JavaCalls::call_virtual(&result, 1819 threadObj, thread_klass, 1820 vmSymbols::exit_method_name(), 1821 vmSymbols::void_method_signature(), 1822 THREAD); 1823 CLEAR_PENDING_EXCEPTION; 1824 } 1825 } 1826 // notify JVMTI 1827 if (JvmtiExport::should_post_thread_life()) { 1828 JvmtiExport::post_thread_end(this); 1829 } 1830 1831 // We have notified the agents that we are exiting, before we go on, 1832 // we must check for a pending external suspend request and honor it 1833 // in order to not surprise the thread that made the suspend request. 1834 while (true) { 1835 { 1836 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1837 if (!is_external_suspend()) { 1838 set_terminated(_thread_exiting); 1839 ThreadService::current_thread_exiting(this); 1840 break; 1841 } 1842 // Implied else: 1843 // Things get a little tricky here. We have a pending external 1844 // suspend request, but we are holding the SR_lock so we 1845 // can't just self-suspend. So we temporarily drop the lock 1846 // and then self-suspend. 1847 } 1848 1849 ThreadBlockInVM tbivm(this); 1850 java_suspend_self(); 1851 1852 // We're done with this suspend request, but we have to loop around 1853 // and check again. Eventually we will get SR_lock without a pending 1854 // external suspend request and will be able to mark ourselves as 1855 // exiting. 1856 } 1857 // no more external suspends are allowed at this point 1858 } else { 1859 // before_exit() has already posted JVMTI THREAD_END events 1860 } 1861 1862 // Notify waiters on thread object. This has to be done after exit() is called 1863 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1864 // group should have the destroyed bit set before waiters are notified). 1865 ensure_join(this); 1866 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1867 1868 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1869 // held by this thread must be released. The spec does not distinguish 1870 // between JNI-acquired and regular Java monitors. We can only see 1871 // regular Java monitors here if monitor enter-exit matching is broken. 1872 // 1873 // Optionally release any monitors for regular JavaThread exits. This 1874 // is provided as a work around for any bugs in monitor enter-exit 1875 // matching. This can be expensive so it is not enabled by default. 1876 // 1877 // ensure_join() ignores IllegalThreadStateExceptions, and so does 1878 // ObjectSynchronizer::release_monitors_owned_by_thread(). 1879 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) { 1880 // Sanity check even though JNI DetachCurrentThread() would have 1881 // returned JNI_ERR if there was a Java frame. JavaThread exit 1882 // should be done executing Java code by the time we get here. 1883 assert(!this->has_last_Java_frame(), 1884 "should not have a Java frame when detaching or exiting"); 1885 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1886 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1887 } 1888 1889 // These things needs to be done while we are still a Java Thread. Make sure that thread 1890 // is in a consistent state, in case GC happens 1891 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1892 1893 if (active_handles() != NULL) { 1894 JNIHandleBlock* block = active_handles(); 1895 set_active_handles(NULL); 1896 JNIHandleBlock::release_block(block); 1897 } 1898 1899 if (free_handle_block() != NULL) { 1900 JNIHandleBlock* block = free_handle_block(); 1901 set_free_handle_block(NULL); 1902 JNIHandleBlock::release_block(block); 1903 } 1904 1905 // These have to be removed while this is still a valid thread. 1906 remove_stack_guard_pages(); 1907 1908 if (UseTLAB) { 1909 tlab().make_parsable(true); // retire TLAB 1910 } 1911 1912 if (JvmtiEnv::environments_might_exist()) { 1913 JvmtiExport::cleanup_thread(this); 1914 } 1915 1916 // We must flush any deferred card marks before removing a thread from 1917 // the list of active threads. 1918 Universe::heap()->flush_deferred_store_barrier(this); 1919 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1920 1921 #if INCLUDE_ALL_GCS 1922 // We must flush the G1-related buffers before removing a thread 1923 // from the list of active threads. We must do this after any deferred 1924 // card marks have been flushed (above) so that any entries that are 1925 // added to the thread's dirty card queue as a result are not lost. 1926 if (UseG1GC) { 1927 flush_barrier_queues(); 1928 } 1929 #endif // INCLUDE_ALL_GCS 1930 1931 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").", 1932 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", 1933 os::current_thread_id()); 1934 1935 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1936 Threads::remove(this); 1937 } 1938 1939 #if INCLUDE_ALL_GCS 1940 // Flush G1-related queues. 1941 void JavaThread::flush_barrier_queues() { 1942 satb_mark_queue().flush(); 1943 dirty_card_queue().flush(); 1944 } 1945 1946 void JavaThread::initialize_queues() { 1947 assert(!SafepointSynchronize::is_at_safepoint(), 1948 "we should not be at a safepoint"); 1949 1950 SATBMarkQueue& satb_queue = satb_mark_queue(); 1951 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1952 // The SATB queue should have been constructed with its active 1953 // field set to false. 1954 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1955 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1956 // If we are creating the thread during a marking cycle, we should 1957 // set the active field of the SATB queue to true. 1958 if (satb_queue_set.is_active()) { 1959 satb_queue.set_active(true); 1960 } 1961 1962 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1963 // The dirty card queue should have been constructed with its 1964 // active field set to true. 1965 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1966 } 1967 #endif // INCLUDE_ALL_GCS 1968 1969 void JavaThread::cleanup_failed_attach_current_thread() { 1970 if (get_thread_profiler() != NULL) { 1971 get_thread_profiler()->disengage(); 1972 ResourceMark rm; 1973 get_thread_profiler()->print(get_thread_name()); 1974 } 1975 1976 if (active_handles() != NULL) { 1977 JNIHandleBlock* block = active_handles(); 1978 set_active_handles(NULL); 1979 JNIHandleBlock::release_block(block); 1980 } 1981 1982 if (free_handle_block() != NULL) { 1983 JNIHandleBlock* block = free_handle_block(); 1984 set_free_handle_block(NULL); 1985 JNIHandleBlock::release_block(block); 1986 } 1987 1988 // These have to be removed while this is still a valid thread. 1989 remove_stack_guard_pages(); 1990 1991 if (UseTLAB) { 1992 tlab().make_parsable(true); // retire TLAB, if any 1993 } 1994 1995 #if INCLUDE_ALL_GCS 1996 if (UseG1GC) { 1997 flush_barrier_queues(); 1998 } 1999 #endif // INCLUDE_ALL_GCS 2000 2001 Threads::remove(this); 2002 delete this; 2003 } 2004 2005 2006 2007 2008 JavaThread* JavaThread::active() { 2009 Thread* thread = Thread::current(); 2010 if (thread->is_Java_thread()) { 2011 return (JavaThread*) thread; 2012 } else { 2013 assert(thread->is_VM_thread(), "this must be a vm thread"); 2014 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2015 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2016 assert(ret->is_Java_thread(), "must be a Java thread"); 2017 return ret; 2018 } 2019 } 2020 2021 bool JavaThread::is_lock_owned(address adr) const { 2022 if (Thread::is_lock_owned(adr)) return true; 2023 2024 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2025 if (chunk->contains(adr)) return true; 2026 } 2027 2028 return false; 2029 } 2030 2031 2032 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2033 chunk->set_next(monitor_chunks()); 2034 set_monitor_chunks(chunk); 2035 } 2036 2037 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2038 guarantee(monitor_chunks() != NULL, "must be non empty"); 2039 if (monitor_chunks() == chunk) { 2040 set_monitor_chunks(chunk->next()); 2041 } else { 2042 MonitorChunk* prev = monitor_chunks(); 2043 while (prev->next() != chunk) prev = prev->next(); 2044 prev->set_next(chunk->next()); 2045 } 2046 } 2047 2048 // JVM support. 2049 2050 // Note: this function shouldn't block if it's called in 2051 // _thread_in_native_trans state (such as from 2052 // check_special_condition_for_native_trans()). 2053 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2054 2055 if (has_last_Java_frame() && has_async_condition()) { 2056 // If we are at a polling page safepoint (not a poll return) 2057 // then we must defer async exception because live registers 2058 // will be clobbered by the exception path. Poll return is 2059 // ok because the call we a returning from already collides 2060 // with exception handling registers and so there is no issue. 2061 // (The exception handling path kills call result registers but 2062 // this is ok since the exception kills the result anyway). 2063 2064 if (is_at_poll_safepoint()) { 2065 // if the code we are returning to has deoptimized we must defer 2066 // the exception otherwise live registers get clobbered on the 2067 // exception path before deoptimization is able to retrieve them. 2068 // 2069 RegisterMap map(this, false); 2070 frame caller_fr = last_frame().sender(&map); 2071 assert(caller_fr.is_compiled_frame(), "what?"); 2072 if (caller_fr.is_deoptimized_frame()) { 2073 log_info(exceptions)("deferred async exception at compiled safepoint"); 2074 return; 2075 } 2076 } 2077 } 2078 2079 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2080 if (condition == _no_async_condition) { 2081 // Conditions have changed since has_special_runtime_exit_condition() 2082 // was called: 2083 // - if we were here only because of an external suspend request, 2084 // then that was taken care of above (or cancelled) so we are done 2085 // - if we were here because of another async request, then it has 2086 // been cleared between the has_special_runtime_exit_condition() 2087 // and now so again we are done 2088 return; 2089 } 2090 2091 // Check for pending async. exception 2092 if (_pending_async_exception != NULL) { 2093 // Only overwrite an already pending exception, if it is not a threadDeath. 2094 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2095 2096 // We cannot call Exceptions::_throw(...) here because we cannot block 2097 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2098 2099 if (log_is_enabled(Info, exceptions)) { 2100 ResourceMark rm; 2101 outputStream* logstream = LogHandle(exceptions)::info_stream(); 2102 logstream->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); 2103 if (has_last_Java_frame()) { 2104 frame f = last_frame(); 2105 logstream->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); 2106 } 2107 logstream->print_cr(" of type: %s", _pending_async_exception->klass()->external_name()); 2108 } 2109 _pending_async_exception = NULL; 2110 clear_has_async_exception(); 2111 } 2112 } 2113 2114 if (check_unsafe_error && 2115 condition == _async_unsafe_access_error && !has_pending_exception()) { 2116 condition = _no_async_condition; // done 2117 switch (thread_state()) { 2118 case _thread_in_vm: { 2119 JavaThread* THREAD = this; 2120 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2121 } 2122 case _thread_in_native: { 2123 ThreadInVMfromNative tiv(this); 2124 JavaThread* THREAD = this; 2125 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2126 } 2127 case _thread_in_Java: { 2128 ThreadInVMfromJava tiv(this); 2129 JavaThread* THREAD = this; 2130 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2131 } 2132 default: 2133 ShouldNotReachHere(); 2134 } 2135 } 2136 2137 assert(condition == _no_async_condition || has_pending_exception() || 2138 (!check_unsafe_error && condition == _async_unsafe_access_error), 2139 "must have handled the async condition, if no exception"); 2140 } 2141 2142 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2143 // 2144 // Check for pending external suspend. Internal suspend requests do 2145 // not use handle_special_runtime_exit_condition(). 2146 // If JNIEnv proxies are allowed, don't self-suspend if the target 2147 // thread is not the current thread. In older versions of jdbx, jdbx 2148 // threads could call into the VM with another thread's JNIEnv so we 2149 // can be here operating on behalf of a suspended thread (4432884). 2150 bool do_self_suspend = is_external_suspend_with_lock(); 2151 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2152 // 2153 // Because thread is external suspended the safepoint code will count 2154 // thread as at a safepoint. This can be odd because we can be here 2155 // as _thread_in_Java which would normally transition to _thread_blocked 2156 // at a safepoint. We would like to mark the thread as _thread_blocked 2157 // before calling java_suspend_self like all other callers of it but 2158 // we must then observe proper safepoint protocol. (We can't leave 2159 // _thread_blocked with a safepoint in progress). However we can be 2160 // here as _thread_in_native_trans so we can't use a normal transition 2161 // constructor/destructor pair because they assert on that type of 2162 // transition. We could do something like: 2163 // 2164 // JavaThreadState state = thread_state(); 2165 // set_thread_state(_thread_in_vm); 2166 // { 2167 // ThreadBlockInVM tbivm(this); 2168 // java_suspend_self() 2169 // } 2170 // set_thread_state(_thread_in_vm_trans); 2171 // if (safepoint) block; 2172 // set_thread_state(state); 2173 // 2174 // but that is pretty messy. Instead we just go with the way the 2175 // code has worked before and note that this is the only path to 2176 // java_suspend_self that doesn't put the thread in _thread_blocked 2177 // mode. 2178 2179 frame_anchor()->make_walkable(this); 2180 java_suspend_self(); 2181 2182 // We might be here for reasons in addition to the self-suspend request 2183 // so check for other async requests. 2184 } 2185 2186 if (check_asyncs) { 2187 check_and_handle_async_exceptions(); 2188 } 2189 } 2190 2191 void JavaThread::send_thread_stop(oop java_throwable) { 2192 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2193 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2194 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2195 2196 // Do not throw asynchronous exceptions against the compiler thread 2197 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2198 if (!can_call_java()) return; 2199 2200 { 2201 // Actually throw the Throwable against the target Thread - however 2202 // only if there is no thread death exception installed already. 2203 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2204 // If the topmost frame is a runtime stub, then we are calling into 2205 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2206 // must deoptimize the caller before continuing, as the compiled exception handler table 2207 // may not be valid 2208 if (has_last_Java_frame()) { 2209 frame f = last_frame(); 2210 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2211 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2212 RegisterMap reg_map(this, UseBiasedLocking); 2213 frame compiled_frame = f.sender(®_map); 2214 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2215 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2216 } 2217 } 2218 } 2219 2220 // Set async. pending exception in thread. 2221 set_pending_async_exception(java_throwable); 2222 2223 if (log_is_enabled(Info, exceptions)) { 2224 ResourceMark rm; 2225 log_info(exceptions)("Pending Async. exception installed of type: %s", 2226 InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2227 } 2228 // for AbortVMOnException flag 2229 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name()); 2230 } 2231 } 2232 2233 2234 // Interrupt thread so it will wake up from a potential wait() 2235 Thread::interrupt(this); 2236 } 2237 2238 // External suspension mechanism. 2239 // 2240 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2241 // to any VM_locks and it is at a transition 2242 // Self-suspension will happen on the transition out of the vm. 2243 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2244 // 2245 // Guarantees on return: 2246 // + Target thread will not execute any new bytecode (that's why we need to 2247 // force a safepoint) 2248 // + Target thread will not enter any new monitors 2249 // 2250 void JavaThread::java_suspend() { 2251 { MutexLocker mu(Threads_lock); 2252 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2253 return; 2254 } 2255 } 2256 2257 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2258 if (!is_external_suspend()) { 2259 // a racing resume has cancelled us; bail out now 2260 return; 2261 } 2262 2263 // suspend is done 2264 uint32_t debug_bits = 0; 2265 // Warning: is_ext_suspend_completed() may temporarily drop the 2266 // SR_lock to allow the thread to reach a stable thread state if 2267 // it is currently in a transient thread state. 2268 if (is_ext_suspend_completed(false /* !called_by_wait */, 2269 SuspendRetryDelay, &debug_bits)) { 2270 return; 2271 } 2272 } 2273 2274 VM_ForceSafepoint vm_suspend; 2275 VMThread::execute(&vm_suspend); 2276 } 2277 2278 // Part II of external suspension. 2279 // A JavaThread self suspends when it detects a pending external suspend 2280 // request. This is usually on transitions. It is also done in places 2281 // where continuing to the next transition would surprise the caller, 2282 // e.g., monitor entry. 2283 // 2284 // Returns the number of times that the thread self-suspended. 2285 // 2286 // Note: DO NOT call java_suspend_self() when you just want to block current 2287 // thread. java_suspend_self() is the second stage of cooperative 2288 // suspension for external suspend requests and should only be used 2289 // to complete an external suspend request. 2290 // 2291 int JavaThread::java_suspend_self() { 2292 int ret = 0; 2293 2294 // we are in the process of exiting so don't suspend 2295 if (is_exiting()) { 2296 clear_external_suspend(); 2297 return ret; 2298 } 2299 2300 assert(_anchor.walkable() || 2301 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2302 "must have walkable stack"); 2303 2304 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2305 2306 assert(!this->is_ext_suspended(), 2307 "a thread trying to self-suspend should not already be suspended"); 2308 2309 if (this->is_suspend_equivalent()) { 2310 // If we are self-suspending as a result of the lifting of a 2311 // suspend equivalent condition, then the suspend_equivalent 2312 // flag is not cleared until we set the ext_suspended flag so 2313 // that wait_for_ext_suspend_completion() returns consistent 2314 // results. 2315 this->clear_suspend_equivalent(); 2316 } 2317 2318 // A racing resume may have cancelled us before we grabbed SR_lock 2319 // above. Or another external suspend request could be waiting for us 2320 // by the time we return from SR_lock()->wait(). The thread 2321 // that requested the suspension may already be trying to walk our 2322 // stack and if we return now, we can change the stack out from under 2323 // it. This would be a "bad thing (TM)" and cause the stack walker 2324 // to crash. We stay self-suspended until there are no more pending 2325 // external suspend requests. 2326 while (is_external_suspend()) { 2327 ret++; 2328 this->set_ext_suspended(); 2329 2330 // _ext_suspended flag is cleared by java_resume() 2331 while (is_ext_suspended()) { 2332 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2333 } 2334 } 2335 2336 return ret; 2337 } 2338 2339 #ifdef ASSERT 2340 // verify the JavaThread has not yet been published in the Threads::list, and 2341 // hence doesn't need protection from concurrent access at this stage 2342 void JavaThread::verify_not_published() { 2343 if (!Threads_lock->owned_by_self()) { 2344 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2345 assert(!Threads::includes(this), 2346 "java thread shouldn't have been published yet!"); 2347 } else { 2348 assert(!Threads::includes(this), 2349 "java thread shouldn't have been published yet!"); 2350 } 2351 } 2352 #endif 2353 2354 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2355 // progress or when _suspend_flags is non-zero. 2356 // Current thread needs to self-suspend if there is a suspend request and/or 2357 // block if a safepoint is in progress. 2358 // Async exception ISN'T checked. 2359 // Note only the ThreadInVMfromNative transition can call this function 2360 // directly and when thread state is _thread_in_native_trans 2361 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2362 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2363 2364 JavaThread *curJT = JavaThread::current(); 2365 bool do_self_suspend = thread->is_external_suspend(); 2366 2367 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2368 2369 // If JNIEnv proxies are allowed, don't self-suspend if the target 2370 // thread is not the current thread. In older versions of jdbx, jdbx 2371 // threads could call into the VM with another thread's JNIEnv so we 2372 // can be here operating on behalf of a suspended thread (4432884). 2373 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2374 JavaThreadState state = thread->thread_state(); 2375 2376 // We mark this thread_blocked state as a suspend-equivalent so 2377 // that a caller to is_ext_suspend_completed() won't be confused. 2378 // The suspend-equivalent state is cleared by java_suspend_self(). 2379 thread->set_suspend_equivalent(); 2380 2381 // If the safepoint code sees the _thread_in_native_trans state, it will 2382 // wait until the thread changes to other thread state. There is no 2383 // guarantee on how soon we can obtain the SR_lock and complete the 2384 // self-suspend request. It would be a bad idea to let safepoint wait for 2385 // too long. Temporarily change the state to _thread_blocked to 2386 // let the VM thread know that this thread is ready for GC. The problem 2387 // of changing thread state is that safepoint could happen just after 2388 // java_suspend_self() returns after being resumed, and VM thread will 2389 // see the _thread_blocked state. We must check for safepoint 2390 // after restoring the state and make sure we won't leave while a safepoint 2391 // is in progress. 2392 thread->set_thread_state(_thread_blocked); 2393 thread->java_suspend_self(); 2394 thread->set_thread_state(state); 2395 // Make sure new state is seen by VM thread 2396 if (os::is_MP()) { 2397 if (UseMembar) { 2398 // Force a fence between the write above and read below 2399 OrderAccess::fence(); 2400 } else { 2401 // Must use this rather than serialization page in particular on Windows 2402 InterfaceSupport::serialize_memory(thread); 2403 } 2404 } 2405 } 2406 2407 if (SafepointSynchronize::do_call_back()) { 2408 // If we are safepointing, then block the caller which may not be 2409 // the same as the target thread (see above). 2410 SafepointSynchronize::block(curJT); 2411 } 2412 2413 if (thread->is_deopt_suspend()) { 2414 thread->clear_deopt_suspend(); 2415 RegisterMap map(thread, false); 2416 frame f = thread->last_frame(); 2417 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2418 f = f.sender(&map); 2419 } 2420 if (f.id() == thread->must_deopt_id()) { 2421 thread->clear_must_deopt_id(); 2422 f.deoptimize(thread); 2423 } else { 2424 fatal("missed deoptimization!"); 2425 } 2426 } 2427 } 2428 2429 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2430 // progress or when _suspend_flags is non-zero. 2431 // Current thread needs to self-suspend if there is a suspend request and/or 2432 // block if a safepoint is in progress. 2433 // Also check for pending async exception (not including unsafe access error). 2434 // Note only the native==>VM/Java barriers can call this function and when 2435 // thread state is _thread_in_native_trans. 2436 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2437 check_safepoint_and_suspend_for_native_trans(thread); 2438 2439 if (thread->has_async_exception()) { 2440 // We are in _thread_in_native_trans state, don't handle unsafe 2441 // access error since that may block. 2442 thread->check_and_handle_async_exceptions(false); 2443 } 2444 } 2445 2446 // This is a variant of the normal 2447 // check_special_condition_for_native_trans with slightly different 2448 // semantics for use by critical native wrappers. It does all the 2449 // normal checks but also performs the transition back into 2450 // thread_in_Java state. This is required so that critical natives 2451 // can potentially block and perform a GC if they are the last thread 2452 // exiting the GCLocker. 2453 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2454 check_special_condition_for_native_trans(thread); 2455 2456 // Finish the transition 2457 thread->set_thread_state(_thread_in_Java); 2458 2459 if (thread->do_critical_native_unlock()) { 2460 ThreadInVMfromJavaNoAsyncException tiv(thread); 2461 GCLocker::unlock_critical(thread); 2462 thread->clear_critical_native_unlock(); 2463 } 2464 } 2465 2466 // We need to guarantee the Threads_lock here, since resumes are not 2467 // allowed during safepoint synchronization 2468 // Can only resume from an external suspension 2469 void JavaThread::java_resume() { 2470 assert_locked_or_safepoint(Threads_lock); 2471 2472 // Sanity check: thread is gone, has started exiting or the thread 2473 // was not externally suspended. 2474 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2475 return; 2476 } 2477 2478 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2479 2480 clear_external_suspend(); 2481 2482 if (is_ext_suspended()) { 2483 clear_ext_suspended(); 2484 SR_lock()->notify_all(); 2485 } 2486 } 2487 2488 size_t JavaThread::_stack_red_zone_size = 0; 2489 size_t JavaThread::_stack_yellow_zone_size = 0; 2490 size_t JavaThread::_stack_reserved_zone_size = 0; 2491 size_t JavaThread::_stack_shadow_zone_size = 0; 2492 2493 void JavaThread::create_stack_guard_pages() { 2494 if (!os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) { return; } 2495 address low_addr = stack_end(); 2496 size_t len = stack_guard_zone_size(); 2497 2498 int allocate = os::allocate_stack_guard_pages(); 2499 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2500 2501 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2502 log_warning(os, thread)("Attempt to allocate stack guard pages failed."); 2503 return; 2504 } 2505 2506 if (os::guard_memory((char *) low_addr, len)) { 2507 _stack_guard_state = stack_guard_enabled; 2508 } else { 2509 log_warning(os, thread)("Attempt to protect stack guard pages failed (" 2510 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2511 if (os::uncommit_memory((char *) low_addr, len)) { 2512 log_warning(os, thread)("Attempt to deallocate stack guard pages failed."); 2513 } 2514 return; 2515 } 2516 2517 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: " 2518 PTR_FORMAT "-" PTR_FORMAT ".", 2519 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2520 2521 } 2522 2523 void JavaThread::remove_stack_guard_pages() { 2524 assert(Thread::current() == this, "from different thread"); 2525 if (_stack_guard_state == stack_guard_unused) return; 2526 address low_addr = stack_end(); 2527 size_t len = stack_guard_zone_size(); 2528 2529 if (os::allocate_stack_guard_pages()) { 2530 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2531 _stack_guard_state = stack_guard_unused; 2532 } else { 2533 log_warning(os, thread)("Attempt to deallocate stack guard pages failed (" 2534 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2535 return; 2536 } 2537 } else { 2538 if (_stack_guard_state == stack_guard_unused) return; 2539 if (os::unguard_memory((char *) low_addr, len)) { 2540 _stack_guard_state = stack_guard_unused; 2541 } else { 2542 log_warning(os, thread)("Attempt to unprotect stack guard pages failed (" 2543 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2544 return; 2545 } 2546 } 2547 2548 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: " 2549 PTR_FORMAT "-" PTR_FORMAT ".", 2550 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2551 2552 } 2553 2554 void JavaThread::enable_stack_reserved_zone() { 2555 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2556 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2557 2558 // The base notation is from the stack's point of view, growing downward. 2559 // We need to adjust it to work correctly with guard_memory() 2560 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2561 2562 guarantee(base < stack_base(),"Error calculating stack reserved zone"); 2563 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone"); 2564 2565 if (os::guard_memory((char *) base, stack_reserved_zone_size())) { 2566 _stack_guard_state = stack_guard_enabled; 2567 } else { 2568 warning("Attempt to guard stack reserved zone failed."); 2569 } 2570 enable_register_stack_guard(); 2571 } 2572 2573 void JavaThread::disable_stack_reserved_zone() { 2574 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2575 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled"); 2576 2577 // Simply return if called for a thread that does not use guard pages. 2578 if (_stack_guard_state == stack_guard_unused) return; 2579 2580 // The base notation is from the stack's point of view, growing downward. 2581 // We need to adjust it to work correctly with guard_memory() 2582 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2583 2584 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) { 2585 _stack_guard_state = stack_guard_reserved_disabled; 2586 } else { 2587 warning("Attempt to unguard stack reserved zone failed."); 2588 } 2589 disable_register_stack_guard(); 2590 } 2591 2592 void JavaThread::enable_stack_yellow_reserved_zone() { 2593 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2594 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2595 2596 // The base notation is from the stacks point of view, growing downward. 2597 // We need to adjust it to work correctly with guard_memory() 2598 address base = stack_red_zone_base(); 2599 2600 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2601 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2602 2603 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) { 2604 _stack_guard_state = stack_guard_enabled; 2605 } else { 2606 warning("Attempt to guard stack yellow zone failed."); 2607 } 2608 enable_register_stack_guard(); 2609 } 2610 2611 void JavaThread::disable_stack_yellow_reserved_zone() { 2612 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2613 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled"); 2614 2615 // Simply return if called for a thread that does not use guard pages. 2616 if (_stack_guard_state == stack_guard_unused) return; 2617 2618 // The base notation is from the stacks point of view, growing downward. 2619 // We need to adjust it to work correctly with guard_memory() 2620 address base = stack_red_zone_base(); 2621 2622 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) { 2623 _stack_guard_state = stack_guard_yellow_reserved_disabled; 2624 } else { 2625 warning("Attempt to unguard stack yellow zone failed."); 2626 } 2627 disable_register_stack_guard(); 2628 } 2629 2630 void JavaThread::enable_stack_red_zone() { 2631 // The base notation is from the stacks point of view, growing downward. 2632 // We need to adjust it to work correctly with guard_memory() 2633 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2634 address base = stack_red_zone_base() - stack_red_zone_size(); 2635 2636 guarantee(base < stack_base(), "Error calculating stack red zone"); 2637 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2638 2639 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2640 warning("Attempt to guard stack red zone failed."); 2641 } 2642 } 2643 2644 void JavaThread::disable_stack_red_zone() { 2645 // The base notation is from the stacks point of view, growing downward. 2646 // We need to adjust it to work correctly with guard_memory() 2647 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2648 address base = stack_red_zone_base() - stack_red_zone_size(); 2649 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2650 warning("Attempt to unguard stack red zone failed."); 2651 } 2652 } 2653 2654 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2655 // ignore is there is no stack 2656 if (!has_last_Java_frame()) return; 2657 // traverse the stack frames. Starts from top frame. 2658 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2659 frame* fr = fst.current(); 2660 f(fr, fst.register_map()); 2661 } 2662 } 2663 2664 2665 #ifndef PRODUCT 2666 // Deoptimization 2667 // Function for testing deoptimization 2668 void JavaThread::deoptimize() { 2669 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2670 StackFrameStream fst(this, UseBiasedLocking); 2671 bool deopt = false; // Dump stack only if a deopt actually happens. 2672 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2673 // Iterate over all frames in the thread and deoptimize 2674 for (; !fst.is_done(); fst.next()) { 2675 if (fst.current()->can_be_deoptimized()) { 2676 2677 if (only_at) { 2678 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2679 // consists of comma or carriage return separated numbers so 2680 // search for the current bci in that string. 2681 address pc = fst.current()->pc(); 2682 nmethod* nm = (nmethod*) fst.current()->cb(); 2683 ScopeDesc* sd = nm->scope_desc_at(pc); 2684 char buffer[8]; 2685 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2686 size_t len = strlen(buffer); 2687 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2688 while (found != NULL) { 2689 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2690 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2691 // Check that the bci found is bracketed by terminators. 2692 break; 2693 } 2694 found = strstr(found + 1, buffer); 2695 } 2696 if (!found) { 2697 continue; 2698 } 2699 } 2700 2701 if (DebugDeoptimization && !deopt) { 2702 deopt = true; // One-time only print before deopt 2703 tty->print_cr("[BEFORE Deoptimization]"); 2704 trace_frames(); 2705 trace_stack(); 2706 } 2707 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2708 } 2709 } 2710 2711 if (DebugDeoptimization && deopt) { 2712 tty->print_cr("[AFTER Deoptimization]"); 2713 trace_frames(); 2714 } 2715 } 2716 2717 2718 // Make zombies 2719 void JavaThread::make_zombies() { 2720 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2721 if (fst.current()->can_be_deoptimized()) { 2722 // it is a Java nmethod 2723 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2724 nm->make_not_entrant(); 2725 } 2726 } 2727 } 2728 #endif // PRODUCT 2729 2730 2731 void JavaThread::deoptimized_wrt_marked_nmethods() { 2732 if (!has_last_Java_frame()) return; 2733 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2734 StackFrameStream fst(this, UseBiasedLocking); 2735 for (; !fst.is_done(); fst.next()) { 2736 if (fst.current()->should_be_deoptimized()) { 2737 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2738 } 2739 } 2740 } 2741 2742 2743 // If the caller is a NamedThread, then remember, in the current scope, 2744 // the given JavaThread in its _processed_thread field. 2745 class RememberProcessedThread: public StackObj { 2746 NamedThread* _cur_thr; 2747 public: 2748 RememberProcessedThread(JavaThread* jthr) { 2749 Thread* thread = Thread::current(); 2750 if (thread->is_Named_thread()) { 2751 _cur_thr = (NamedThread *)thread; 2752 _cur_thr->set_processed_thread(jthr); 2753 } else { 2754 _cur_thr = NULL; 2755 } 2756 } 2757 2758 ~RememberProcessedThread() { 2759 if (_cur_thr) { 2760 _cur_thr->set_processed_thread(NULL); 2761 } 2762 } 2763 }; 2764 2765 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2766 // Verify that the deferred card marks have been flushed. 2767 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2768 2769 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2770 // since there may be more than one thread using each ThreadProfiler. 2771 2772 // Traverse the GCHandles 2773 Thread::oops_do(f, cld_f, cf); 2774 2775 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);) 2776 2777 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2778 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2779 2780 if (has_last_Java_frame()) { 2781 // Record JavaThread to GC thread 2782 RememberProcessedThread rpt(this); 2783 2784 // Traverse the privileged stack 2785 if (_privileged_stack_top != NULL) { 2786 _privileged_stack_top->oops_do(f); 2787 } 2788 2789 // traverse the registered growable array 2790 if (_array_for_gc != NULL) { 2791 for (int index = 0; index < _array_for_gc->length(); index++) { 2792 f->do_oop(_array_for_gc->adr_at(index)); 2793 } 2794 } 2795 2796 // Traverse the monitor chunks 2797 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2798 chunk->oops_do(f); 2799 } 2800 2801 // Traverse the execution stack 2802 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2803 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2804 } 2805 } 2806 2807 // callee_target is never live across a gc point so NULL it here should 2808 // it still contain a methdOop. 2809 2810 set_callee_target(NULL); 2811 2812 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2813 // If we have deferred set_locals there might be oops waiting to be 2814 // written 2815 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2816 if (list != NULL) { 2817 for (int i = 0; i < list->length(); i++) { 2818 list->at(i)->oops_do(f); 2819 } 2820 } 2821 2822 // Traverse instance variables at the end since the GC may be moving things 2823 // around using this function 2824 f->do_oop((oop*) &_threadObj); 2825 f->do_oop((oop*) &_vm_result); 2826 f->do_oop((oop*) &_exception_oop); 2827 f->do_oop((oop*) &_pending_async_exception); 2828 2829 if (jvmti_thread_state() != NULL) { 2830 jvmti_thread_state()->oops_do(f); 2831 } 2832 } 2833 2834 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2835 Thread::nmethods_do(cf); // (super method is a no-op) 2836 2837 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2838 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2839 2840 if (has_last_Java_frame()) { 2841 // Traverse the execution stack 2842 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2843 fst.current()->nmethods_do(cf); 2844 } 2845 } 2846 } 2847 2848 void JavaThread::metadata_do(void f(Metadata*)) { 2849 if (has_last_Java_frame()) { 2850 // Traverse the execution stack to call f() on the methods in the stack 2851 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2852 fst.current()->metadata_do(f); 2853 } 2854 } else if (is_Compiler_thread()) { 2855 // need to walk ciMetadata in current compile tasks to keep alive. 2856 CompilerThread* ct = (CompilerThread*)this; 2857 if (ct->env() != NULL) { 2858 ct->env()->metadata_do(f); 2859 } 2860 if (ct->task() != NULL) { 2861 ct->task()->metadata_do(f); 2862 } 2863 } 2864 } 2865 2866 // Printing 2867 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2868 switch (_thread_state) { 2869 case _thread_uninitialized: return "_thread_uninitialized"; 2870 case _thread_new: return "_thread_new"; 2871 case _thread_new_trans: return "_thread_new_trans"; 2872 case _thread_in_native: return "_thread_in_native"; 2873 case _thread_in_native_trans: return "_thread_in_native_trans"; 2874 case _thread_in_vm: return "_thread_in_vm"; 2875 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2876 case _thread_in_Java: return "_thread_in_Java"; 2877 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2878 case _thread_blocked: return "_thread_blocked"; 2879 case _thread_blocked_trans: return "_thread_blocked_trans"; 2880 default: return "unknown thread state"; 2881 } 2882 } 2883 2884 #ifndef PRODUCT 2885 void JavaThread::print_thread_state_on(outputStream *st) const { 2886 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2887 }; 2888 void JavaThread::print_thread_state() const { 2889 print_thread_state_on(tty); 2890 } 2891 #endif // PRODUCT 2892 2893 // Called by Threads::print() for VM_PrintThreads operation 2894 void JavaThread::print_on(outputStream *st) const { 2895 st->print("\"%s\" ", get_thread_name()); 2896 oop thread_oop = threadObj(); 2897 if (thread_oop != NULL) { 2898 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2899 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2900 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2901 } 2902 Thread::print_on(st); 2903 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2904 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2905 if (thread_oop != NULL) { 2906 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2907 } 2908 #ifndef PRODUCT 2909 print_thread_state_on(st); 2910 _safepoint_state->print_on(st); 2911 #endif // PRODUCT 2912 if (is_Compiler_thread()) { 2913 CompilerThread* ct = (CompilerThread*)this; 2914 if (ct->task() != NULL) { 2915 st->print(" Compiling: "); 2916 ct->task()->print(st, NULL, true, false); 2917 } else { 2918 st->print(" No compile task"); 2919 } 2920 st->cr(); 2921 } 2922 } 2923 2924 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const { 2925 st->print("%s", get_thread_name_string(buf, buflen)); 2926 } 2927 2928 // Called by fatal error handler. The difference between this and 2929 // JavaThread::print() is that we can't grab lock or allocate memory. 2930 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2931 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2932 oop thread_obj = threadObj(); 2933 if (thread_obj != NULL) { 2934 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2935 } 2936 st->print(" ["); 2937 st->print("%s", _get_thread_state_name(_thread_state)); 2938 if (osthread()) { 2939 st->print(", id=%d", osthread()->thread_id()); 2940 } 2941 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2942 p2i(stack_end()), p2i(stack_base())); 2943 st->print("]"); 2944 return; 2945 } 2946 2947 // Verification 2948 2949 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2950 2951 void JavaThread::verify() { 2952 // Verify oops in the thread. 2953 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2954 2955 // Verify the stack frames. 2956 frames_do(frame_verify); 2957 } 2958 2959 // CR 6300358 (sub-CR 2137150) 2960 // Most callers of this method assume that it can't return NULL but a 2961 // thread may not have a name whilst it is in the process of attaching to 2962 // the VM - see CR 6412693, and there are places where a JavaThread can be 2963 // seen prior to having it's threadObj set (eg JNI attaching threads and 2964 // if vm exit occurs during initialization). These cases can all be accounted 2965 // for such that this method never returns NULL. 2966 const char* JavaThread::get_thread_name() const { 2967 #ifdef ASSERT 2968 // early safepoints can hit while current thread does not yet have TLS 2969 if (!SafepointSynchronize::is_at_safepoint()) { 2970 Thread *cur = Thread::current(); 2971 if (!(cur->is_Java_thread() && cur == this)) { 2972 // Current JavaThreads are allowed to get their own name without 2973 // the Threads_lock. 2974 assert_locked_or_safepoint(Threads_lock); 2975 } 2976 } 2977 #endif // ASSERT 2978 return get_thread_name_string(); 2979 } 2980 2981 // Returns a non-NULL representation of this thread's name, or a suitable 2982 // descriptive string if there is no set name 2983 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2984 const char* name_str; 2985 oop thread_obj = threadObj(); 2986 if (thread_obj != NULL) { 2987 oop name = java_lang_Thread::name(thread_obj); 2988 if (name != NULL) { 2989 if (buf == NULL) { 2990 name_str = java_lang_String::as_utf8_string(name); 2991 } else { 2992 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 2993 } 2994 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2995 name_str = "<no-name - thread is attaching>"; 2996 } else { 2997 name_str = Thread::name(); 2998 } 2999 } else { 3000 name_str = Thread::name(); 3001 } 3002 assert(name_str != NULL, "unexpected NULL thread name"); 3003 return name_str; 3004 } 3005 3006 3007 const char* JavaThread::get_threadgroup_name() const { 3008 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 3009 oop thread_obj = threadObj(); 3010 if (thread_obj != NULL) { 3011 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 3012 if (thread_group != NULL) { 3013 // ThreadGroup.name can be null 3014 return java_lang_ThreadGroup::name(thread_group); 3015 } 3016 } 3017 return NULL; 3018 } 3019 3020 const char* JavaThread::get_parent_name() const { 3021 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 3022 oop thread_obj = threadObj(); 3023 if (thread_obj != NULL) { 3024 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 3025 if (thread_group != NULL) { 3026 oop parent = java_lang_ThreadGroup::parent(thread_group); 3027 if (parent != NULL) { 3028 // ThreadGroup.name can be null 3029 return java_lang_ThreadGroup::name(parent); 3030 } 3031 } 3032 } 3033 return NULL; 3034 } 3035 3036 ThreadPriority JavaThread::java_priority() const { 3037 oop thr_oop = threadObj(); 3038 if (thr_oop == NULL) return NormPriority; // Bootstrapping 3039 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 3040 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 3041 return priority; 3042 } 3043 3044 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 3045 3046 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3047 // Link Java Thread object <-> C++ Thread 3048 3049 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3050 // and put it into a new Handle. The Handle "thread_oop" can then 3051 // be used to pass the C++ thread object to other methods. 3052 3053 // Set the Java level thread object (jthread) field of the 3054 // new thread (a JavaThread *) to C++ thread object using the 3055 // "thread_oop" handle. 3056 3057 // Set the thread field (a JavaThread *) of the 3058 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3059 3060 Handle thread_oop(Thread::current(), 3061 JNIHandles::resolve_non_null(jni_thread)); 3062 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3063 "must be initialized"); 3064 set_threadObj(thread_oop()); 3065 java_lang_Thread::set_thread(thread_oop(), this); 3066 3067 if (prio == NoPriority) { 3068 prio = java_lang_Thread::priority(thread_oop()); 3069 assert(prio != NoPriority, "A valid priority should be present"); 3070 } 3071 3072 // Push the Java priority down to the native thread; needs Threads_lock 3073 Thread::set_priority(this, prio); 3074 3075 prepare_ext(); 3076 3077 // Add the new thread to the Threads list and set it in motion. 3078 // We must have threads lock in order to call Threads::add. 3079 // It is crucial that we do not block before the thread is 3080 // added to the Threads list for if a GC happens, then the java_thread oop 3081 // will not be visited by GC. 3082 Threads::add(this); 3083 } 3084 3085 oop JavaThread::current_park_blocker() { 3086 // Support for JSR-166 locks 3087 oop thread_oop = threadObj(); 3088 if (thread_oop != NULL && 3089 JDK_Version::current().supports_thread_park_blocker()) { 3090 return java_lang_Thread::park_blocker(thread_oop); 3091 } 3092 return NULL; 3093 } 3094 3095 3096 void JavaThread::print_stack_on(outputStream* st) { 3097 if (!has_last_Java_frame()) return; 3098 ResourceMark rm; 3099 HandleMark hm; 3100 3101 RegisterMap reg_map(this); 3102 vframe* start_vf = last_java_vframe(®_map); 3103 int count = 0; 3104 for (vframe* f = start_vf; f; f = f->sender()) { 3105 if (f->is_java_frame()) { 3106 javaVFrame* jvf = javaVFrame::cast(f); 3107 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3108 3109 // Print out lock information 3110 if (JavaMonitorsInStackTrace) { 3111 jvf->print_lock_info_on(st, count); 3112 } 3113 } else { 3114 // Ignore non-Java frames 3115 } 3116 3117 // Bail-out case for too deep stacks 3118 count++; 3119 if (MaxJavaStackTraceDepth == count) return; 3120 } 3121 } 3122 3123 3124 // JVMTI PopFrame support 3125 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3126 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3127 if (in_bytes(size_in_bytes) != 0) { 3128 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3129 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3130 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3131 } 3132 } 3133 3134 void* JavaThread::popframe_preserved_args() { 3135 return _popframe_preserved_args; 3136 } 3137 3138 ByteSize JavaThread::popframe_preserved_args_size() { 3139 return in_ByteSize(_popframe_preserved_args_size); 3140 } 3141 3142 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3143 int sz = in_bytes(popframe_preserved_args_size()); 3144 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3145 return in_WordSize(sz / wordSize); 3146 } 3147 3148 void JavaThread::popframe_free_preserved_args() { 3149 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3150 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3151 _popframe_preserved_args = NULL; 3152 _popframe_preserved_args_size = 0; 3153 } 3154 3155 #ifndef PRODUCT 3156 3157 void JavaThread::trace_frames() { 3158 tty->print_cr("[Describe stack]"); 3159 int frame_no = 1; 3160 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3161 tty->print(" %d. ", frame_no++); 3162 fst.current()->print_value_on(tty, this); 3163 tty->cr(); 3164 } 3165 } 3166 3167 class PrintAndVerifyOopClosure: public OopClosure { 3168 protected: 3169 template <class T> inline void do_oop_work(T* p) { 3170 oop obj = oopDesc::load_decode_heap_oop(p); 3171 if (obj == NULL) return; 3172 tty->print(INTPTR_FORMAT ": ", p2i(p)); 3173 if (obj->is_oop_or_null()) { 3174 if (obj->is_objArray()) { 3175 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); 3176 } else { 3177 obj->print(); 3178 } 3179 } else { 3180 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); 3181 } 3182 tty->cr(); 3183 } 3184 public: 3185 virtual void do_oop(oop* p) { do_oop_work(p); } 3186 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3187 }; 3188 3189 3190 static void oops_print(frame* f, const RegisterMap *map) { 3191 PrintAndVerifyOopClosure print; 3192 f->print_value(); 3193 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3194 } 3195 3196 // Print our all the locations that contain oops and whether they are 3197 // valid or not. This useful when trying to find the oldest frame 3198 // where an oop has gone bad since the frame walk is from youngest to 3199 // oldest. 3200 void JavaThread::trace_oops() { 3201 tty->print_cr("[Trace oops]"); 3202 frames_do(oops_print); 3203 } 3204 3205 3206 #ifdef ASSERT 3207 // Print or validate the layout of stack frames 3208 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3209 ResourceMark rm; 3210 PRESERVE_EXCEPTION_MARK; 3211 FrameValues values; 3212 int frame_no = 0; 3213 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3214 fst.current()->describe(values, ++frame_no); 3215 if (depth == frame_no) break; 3216 } 3217 if (validate_only) { 3218 values.validate(); 3219 } else { 3220 tty->print_cr("[Describe stack layout]"); 3221 values.print(this); 3222 } 3223 } 3224 #endif 3225 3226 void JavaThread::trace_stack_from(vframe* start_vf) { 3227 ResourceMark rm; 3228 int vframe_no = 1; 3229 for (vframe* f = start_vf; f; f = f->sender()) { 3230 if (f->is_java_frame()) { 3231 javaVFrame::cast(f)->print_activation(vframe_no++); 3232 } else { 3233 f->print(); 3234 } 3235 if (vframe_no > StackPrintLimit) { 3236 tty->print_cr("...<more frames>..."); 3237 return; 3238 } 3239 } 3240 } 3241 3242 3243 void JavaThread::trace_stack() { 3244 if (!has_last_Java_frame()) return; 3245 ResourceMark rm; 3246 HandleMark hm; 3247 RegisterMap reg_map(this); 3248 trace_stack_from(last_java_vframe(®_map)); 3249 } 3250 3251 3252 #endif // PRODUCT 3253 3254 3255 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3256 assert(reg_map != NULL, "a map must be given"); 3257 frame f = last_frame(); 3258 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3259 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3260 } 3261 return NULL; 3262 } 3263 3264 3265 Klass* JavaThread::security_get_caller_class(int depth) { 3266 vframeStream vfst(this); 3267 vfst.security_get_caller_frame(depth); 3268 if (!vfst.at_end()) { 3269 return vfst.method()->method_holder(); 3270 } 3271 return NULL; 3272 } 3273 3274 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3275 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3276 CompileBroker::compiler_thread_loop(); 3277 } 3278 3279 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3280 NMethodSweeper::sweeper_loop(); 3281 } 3282 3283 // Create a CompilerThread 3284 CompilerThread::CompilerThread(CompileQueue* queue, 3285 CompilerCounters* counters) 3286 : JavaThread(&compiler_thread_entry) { 3287 _env = NULL; 3288 _log = NULL; 3289 _task = NULL; 3290 _queue = queue; 3291 _counters = counters; 3292 _buffer_blob = NULL; 3293 _compiler = NULL; 3294 3295 #ifndef PRODUCT 3296 _ideal_graph_printer = NULL; 3297 #endif 3298 } 3299 3300 bool CompilerThread::can_call_java() const { 3301 return _compiler != NULL && _compiler->is_jvmci(); 3302 } 3303 3304 // Create sweeper thread 3305 CodeCacheSweeperThread::CodeCacheSweeperThread() 3306 : JavaThread(&sweeper_thread_entry) { 3307 _scanned_nmethod = NULL; 3308 } 3309 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3310 JavaThread::oops_do(f, cld_f, cf); 3311 if (_scanned_nmethod != NULL && cf != NULL) { 3312 // Safepoints can occur when the sweeper is scanning an nmethod so 3313 // process it here to make sure it isn't unloaded in the middle of 3314 // a scan. 3315 cf->do_code_blob(_scanned_nmethod); 3316 } 3317 } 3318 3319 3320 // ======= Threads ======== 3321 3322 // The Threads class links together all active threads, and provides 3323 // operations over all threads. It is protected by its own Mutex 3324 // lock, which is also used in other contexts to protect thread 3325 // operations from having the thread being operated on from exiting 3326 // and going away unexpectedly (e.g., safepoint synchronization) 3327 3328 JavaThread* Threads::_thread_list = NULL; 3329 int Threads::_number_of_threads = 0; 3330 int Threads::_number_of_non_daemon_threads = 0; 3331 int Threads::_return_code = 0; 3332 int Threads::_thread_claim_parity = 0; 3333 size_t JavaThread::_stack_size_at_create = 0; 3334 #ifdef ASSERT 3335 bool Threads::_vm_complete = false; 3336 #endif 3337 3338 // All JavaThreads 3339 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3340 3341 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3342 void Threads::threads_do(ThreadClosure* tc) { 3343 assert_locked_or_safepoint(Threads_lock); 3344 // ALL_JAVA_THREADS iterates through all JavaThreads 3345 ALL_JAVA_THREADS(p) { 3346 tc->do_thread(p); 3347 } 3348 // Someday we could have a table or list of all non-JavaThreads. 3349 // For now, just manually iterate through them. 3350 tc->do_thread(VMThread::vm_thread()); 3351 Universe::heap()->gc_threads_do(tc); 3352 WatcherThread *wt = WatcherThread::watcher_thread(); 3353 // Strictly speaking, the following NULL check isn't sufficient to make sure 3354 // the data for WatcherThread is still valid upon being examined. However, 3355 // considering that WatchThread terminates when the VM is on the way to 3356 // exit at safepoint, the chance of the above is extremely small. The right 3357 // way to prevent termination of WatcherThread would be to acquire 3358 // Terminator_lock, but we can't do that without violating the lock rank 3359 // checking in some cases. 3360 if (wt != NULL) { 3361 tc->do_thread(wt); 3362 } 3363 3364 // If CompilerThreads ever become non-JavaThreads, add them here 3365 } 3366 3367 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3368 TraceStartupTime timer("Initialize java.lang classes"); 3369 3370 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3371 create_vm_init_libraries(); 3372 } 3373 3374 initialize_class(vmSymbols::java_lang_String(), CHECK); 3375 3376 // Inject CompactStrings value after the static initializers for String ran. 3377 java_lang_String::set_compact_strings(CompactStrings); 3378 3379 // Initialize java_lang.System (needed before creating the thread) 3380 initialize_class(vmSymbols::java_lang_System(), CHECK); 3381 // The VM creates & returns objects of this class. Make sure it's initialized. 3382 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3383 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3384 Handle thread_group = create_initial_thread_group(CHECK); 3385 Universe::set_main_thread_group(thread_group()); 3386 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3387 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3388 main_thread->set_threadObj(thread_object); 3389 // Set thread status to running since main thread has 3390 // been started and running. 3391 java_lang_Thread::set_thread_status(thread_object, 3392 java_lang_Thread::RUNNABLE); 3393 3394 // The VM preresolves methods to these classes. Make sure that they get initialized 3395 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3396 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3397 call_initializeSystemClass(CHECK); 3398 3399 // get the Java runtime name after java.lang.System is initialized 3400 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3401 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3402 3403 // an instance of OutOfMemory exception has been allocated earlier 3404 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3405 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3406 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3407 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3408 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3409 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3410 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3411 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3412 } 3413 3414 void Threads::initialize_jsr292_core_classes(TRAPS) { 3415 TraceStartupTime timer("Initialize java.lang.invoke classes"); 3416 3417 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3418 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3419 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3420 } 3421 3422 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3423 extern void JDK_Version_init(); 3424 3425 // Preinitialize version info. 3426 VM_Version::early_initialize(); 3427 3428 // Check version 3429 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3430 3431 // Initialize library-based TLS 3432 ThreadLocalStorage::init(); 3433 3434 // Initialize the output stream module 3435 ostream_init(); 3436 3437 // Process java launcher properties. 3438 Arguments::process_sun_java_launcher_properties(args); 3439 3440 // Initialize the os module 3441 os::init(); 3442 3443 // Record VM creation timing statistics 3444 TraceVmCreationTime create_vm_timer; 3445 create_vm_timer.start(); 3446 3447 // Initialize system properties. 3448 Arguments::init_system_properties(); 3449 3450 // So that JDK version can be used as a discriminator when parsing arguments 3451 JDK_Version_init(); 3452 3453 // Update/Initialize System properties after JDK version number is known 3454 Arguments::init_version_specific_system_properties(); 3455 3456 // Make sure to initialize log configuration *before* parsing arguments 3457 LogConfiguration::initialize(create_vm_timer.begin_time()); 3458 3459 // Parse arguments 3460 jint parse_result = Arguments::parse(args); 3461 if (parse_result != JNI_OK) return parse_result; 3462 3463 os::init_before_ergo(); 3464 3465 jint ergo_result = Arguments::apply_ergo(); 3466 if (ergo_result != JNI_OK) return ergo_result; 3467 3468 // Final check of all ranges after ergonomics which may change values. 3469 if (!CommandLineFlagRangeList::check_ranges()) { 3470 return JNI_EINVAL; 3471 } 3472 3473 // Final check of all 'AfterErgo' constraints after ergonomics which may change values. 3474 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo); 3475 if (!constraint_result) { 3476 return JNI_EINVAL; 3477 } 3478 3479 if (PauseAtStartup) { 3480 os::pause(); 3481 } 3482 3483 HOTSPOT_VM_INIT_BEGIN(); 3484 3485 // Timing (must come after argument parsing) 3486 TraceStartupTime timer("Create VM"); 3487 3488 // Initialize the os module after parsing the args 3489 jint os_init_2_result = os::init_2(); 3490 if (os_init_2_result != JNI_OK) return os_init_2_result; 3491 3492 jint adjust_after_os_result = Arguments::adjust_after_os(); 3493 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3494 3495 // Initialize output stream logging 3496 ostream_init_log(); 3497 3498 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3499 // Must be before create_vm_init_agents() 3500 if (Arguments::init_libraries_at_startup()) { 3501 convert_vm_init_libraries_to_agents(); 3502 } 3503 3504 // Launch -agentlib/-agentpath and converted -Xrun agents 3505 if (Arguments::init_agents_at_startup()) { 3506 create_vm_init_agents(); 3507 } 3508 3509 // Initialize Threads state 3510 _thread_list = NULL; 3511 _number_of_threads = 0; 3512 _number_of_non_daemon_threads = 0; 3513 3514 // Initialize global data structures and create system classes in heap 3515 vm_init_globals(); 3516 3517 #if INCLUDE_JVMCI 3518 if (JVMCICounterSize > 0) { 3519 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 3520 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize); 3521 } else { 3522 JavaThread::_jvmci_old_thread_counters = NULL; 3523 } 3524 #endif // INCLUDE_JVMCI 3525 3526 // Attach the main thread to this os thread 3527 JavaThread* main_thread = new JavaThread(); 3528 main_thread->set_thread_state(_thread_in_vm); 3529 main_thread->initialize_thread_current(); 3530 // must do this before set_active_handles 3531 main_thread->record_stack_base_and_size(); 3532 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3533 3534 if (!main_thread->set_as_starting_thread()) { 3535 vm_shutdown_during_initialization( 3536 "Failed necessary internal allocation. Out of swap space"); 3537 delete main_thread; 3538 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3539 return JNI_ENOMEM; 3540 } 3541 3542 // Enable guard page *after* os::create_main_thread(), otherwise it would 3543 // crash Linux VM, see notes in os_linux.cpp. 3544 main_thread->create_stack_guard_pages(); 3545 3546 // Initialize Java-Level synchronization subsystem 3547 ObjectMonitor::Initialize(); 3548 3549 // Initialize global modules 3550 jint status = init_globals(); 3551 if (status != JNI_OK) { 3552 delete main_thread; 3553 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3554 return status; 3555 } 3556 3557 if (TRACE_INITIALIZE() != JNI_OK) { 3558 vm_exit_during_initialization("Failed to initialize tracing backend"); 3559 } 3560 3561 // Should be done after the heap is fully created 3562 main_thread->cache_global_variables(); 3563 3564 HandleMark hm; 3565 3566 { MutexLocker mu(Threads_lock); 3567 Threads::add(main_thread); 3568 } 3569 3570 // Any JVMTI raw monitors entered in onload will transition into 3571 // real raw monitor. VM is setup enough here for raw monitor enter. 3572 JvmtiExport::transition_pending_onload_raw_monitors(); 3573 3574 // Create the VMThread 3575 { TraceStartupTime timer("Start VMThread"); 3576 3577 VMThread::create(); 3578 Thread* vmthread = VMThread::vm_thread(); 3579 3580 if (!os::create_thread(vmthread, os::vm_thread)) { 3581 vm_exit_during_initialization("Cannot create VM thread. " 3582 "Out of system resources."); 3583 } 3584 3585 // Wait for the VM thread to become ready, and VMThread::run to initialize 3586 // Monitors can have spurious returns, must always check another state flag 3587 { 3588 MutexLocker ml(Notify_lock); 3589 os::start_thread(vmthread); 3590 while (vmthread->active_handles() == NULL) { 3591 Notify_lock->wait(); 3592 } 3593 } 3594 } 3595 3596 assert(Universe::is_fully_initialized(), "not initialized"); 3597 if (VerifyDuringStartup) { 3598 // Make sure we're starting with a clean slate. 3599 VM_Verify verify_op; 3600 VMThread::execute(&verify_op); 3601 } 3602 3603 Thread* THREAD = Thread::current(); 3604 3605 // At this point, the Universe is initialized, but we have not executed 3606 // any byte code. Now is a good time (the only time) to dump out the 3607 // internal state of the JVM for sharing. 3608 if (DumpSharedSpaces) { 3609 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3610 ShouldNotReachHere(); 3611 } 3612 3613 // Always call even when there are not JVMTI environments yet, since environments 3614 // may be attached late and JVMTI must track phases of VM execution 3615 JvmtiExport::enter_start_phase(); 3616 3617 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3618 JvmtiExport::post_vm_start(); 3619 3620 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3621 3622 // We need this for ClassDataSharing - the initial vm.info property is set 3623 // with the default value of CDS "sharing" which may be reset through 3624 // command line options. 3625 reset_vm_info_property(CHECK_JNI_ERR); 3626 3627 quicken_jni_functions(); 3628 3629 // No more stub generation allowed after that point. 3630 StubCodeDesc::freeze(); 3631 3632 // Set flag that basic initialization has completed. Used by exceptions and various 3633 // debug stuff, that does not work until all basic classes have been initialized. 3634 set_init_completed(); 3635 3636 LogConfiguration::post_initialize(); 3637 Metaspace::post_initialize(); 3638 3639 HOTSPOT_VM_INIT_END(); 3640 3641 // record VM initialization completion time 3642 #if INCLUDE_MANAGEMENT 3643 Management::record_vm_init_completed(); 3644 #endif // INCLUDE_MANAGEMENT 3645 3646 // Compute system loader. Note that this has to occur after set_init_completed, since 3647 // valid exceptions may be thrown in the process. 3648 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3649 // set_init_completed has just been called, causing exceptions not to be shortcut 3650 // anymore. We call vm_exit_during_initialization directly instead. 3651 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR)); 3652 3653 #if INCLUDE_ALL_GCS 3654 // Support for ConcurrentMarkSweep. This should be cleaned up 3655 // and better encapsulated. The ugly nested if test would go away 3656 // once things are properly refactored. XXX YSR 3657 if (UseConcMarkSweepGC || UseG1GC) { 3658 if (UseConcMarkSweepGC) { 3659 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3660 } else { 3661 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3662 } 3663 } 3664 #endif // INCLUDE_ALL_GCS 3665 3666 // Always call even when there are not JVMTI environments yet, since environments 3667 // may be attached late and JVMTI must track phases of VM execution 3668 JvmtiExport::enter_live_phase(); 3669 3670 // Signal Dispatcher needs to be started before VMInit event is posted 3671 os::signal_init(); 3672 3673 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3674 if (!DisableAttachMechanism) { 3675 AttachListener::vm_start(); 3676 if (StartAttachListener || AttachListener::init_at_startup()) { 3677 AttachListener::init(); 3678 } 3679 } 3680 3681 // Launch -Xrun agents 3682 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3683 // back-end can launch with -Xdebug -Xrunjdwp. 3684 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3685 create_vm_init_libraries(); 3686 } 3687 3688 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3689 JvmtiExport::post_vm_initialized(); 3690 3691 if (TRACE_START() != JNI_OK) { 3692 vm_exit_during_initialization("Failed to start tracing backend."); 3693 } 3694 3695 if (CleanChunkPoolAsync) { 3696 Chunk::start_chunk_pool_cleaner_task(); 3697 } 3698 3699 // initialize compiler(s) 3700 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI 3701 CompileBroker::compilation_init(CHECK_JNI_ERR); 3702 #endif 3703 3704 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3705 // It is done after compilers are initialized, because otherwise compilations of 3706 // signature polymorphic MH intrinsics can be missed 3707 // (see SystemDictionary::find_method_handle_intrinsic). 3708 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3709 3710 #if INCLUDE_MANAGEMENT 3711 Management::initialize(THREAD); 3712 3713 if (HAS_PENDING_EXCEPTION) { 3714 // management agent fails to start possibly due to 3715 // configuration problem and is responsible for printing 3716 // stack trace if appropriate. Simply exit VM. 3717 vm_exit(1); 3718 } 3719 #endif // INCLUDE_MANAGEMENT 3720 3721 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3722 if (MemProfiling) MemProfiler::engage(); 3723 StatSampler::engage(); 3724 if (CheckJNICalls) JniPeriodicChecker::engage(); 3725 3726 BiasedLocking::init(); 3727 3728 #if INCLUDE_RTM_OPT 3729 RTMLockingCounters::init(); 3730 #endif 3731 3732 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3733 call_postVMInitHook(THREAD); 3734 // The Java side of PostVMInitHook.run must deal with all 3735 // exceptions and provide means of diagnosis. 3736 if (HAS_PENDING_EXCEPTION) { 3737 CLEAR_PENDING_EXCEPTION; 3738 } 3739 } 3740 3741 { 3742 MutexLocker ml(PeriodicTask_lock); 3743 // Make sure the WatcherThread can be started by WatcherThread::start() 3744 // or by dynamic enrollment. 3745 WatcherThread::make_startable(); 3746 // Start up the WatcherThread if there are any periodic tasks 3747 // NOTE: All PeriodicTasks should be registered by now. If they 3748 // aren't, late joiners might appear to start slowly (we might 3749 // take a while to process their first tick). 3750 if (PeriodicTask::num_tasks() > 0) { 3751 WatcherThread::start(); 3752 } 3753 } 3754 3755 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM); 3756 3757 create_vm_timer.end(); 3758 #ifdef ASSERT 3759 _vm_complete = true; 3760 #endif 3761 return JNI_OK; 3762 } 3763 3764 // type for the Agent_OnLoad and JVM_OnLoad entry points 3765 extern "C" { 3766 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3767 } 3768 // Find a command line agent library and return its entry point for 3769 // -agentlib: -agentpath: -Xrun 3770 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3771 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 3772 const char *on_load_symbols[], 3773 size_t num_symbol_entries) { 3774 OnLoadEntry_t on_load_entry = NULL; 3775 void *library = NULL; 3776 3777 if (!agent->valid()) { 3778 char buffer[JVM_MAXPATHLEN]; 3779 char ebuf[1024] = ""; 3780 const char *name = agent->name(); 3781 const char *msg = "Could not find agent library "; 3782 3783 // First check to see if agent is statically linked into executable 3784 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3785 library = agent->os_lib(); 3786 } else if (agent->is_absolute_path()) { 3787 library = os::dll_load(name, ebuf, sizeof ebuf); 3788 if (library == NULL) { 3789 const char *sub_msg = " in absolute path, with error: "; 3790 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3791 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3792 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3793 // If we can't find the agent, exit. 3794 vm_exit_during_initialization(buf, NULL); 3795 FREE_C_HEAP_ARRAY(char, buf); 3796 } 3797 } else { 3798 // Try to load the agent from the standard dll directory 3799 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3800 name)) { 3801 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3802 } 3803 if (library == NULL) { // Try the local directory 3804 char ns[1] = {0}; 3805 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3806 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3807 } 3808 if (library == NULL) { 3809 const char *sub_msg = " on the library path, with error: "; 3810 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3811 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3812 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3813 // If we can't find the agent, exit. 3814 vm_exit_during_initialization(buf, NULL); 3815 FREE_C_HEAP_ARRAY(char, buf); 3816 } 3817 } 3818 } 3819 agent->set_os_lib(library); 3820 agent->set_valid(); 3821 } 3822 3823 // Find the OnLoad function. 3824 on_load_entry = 3825 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3826 false, 3827 on_load_symbols, 3828 num_symbol_entries)); 3829 return on_load_entry; 3830 } 3831 3832 // Find the JVM_OnLoad entry point 3833 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3834 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3835 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3836 } 3837 3838 // Find the Agent_OnLoad entry point 3839 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3840 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3841 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3842 } 3843 3844 // For backwards compatibility with -Xrun 3845 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3846 // treated like -agentpath: 3847 // Must be called before agent libraries are created 3848 void Threads::convert_vm_init_libraries_to_agents() { 3849 AgentLibrary* agent; 3850 AgentLibrary* next; 3851 3852 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3853 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3854 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3855 3856 // If there is an JVM_OnLoad function it will get called later, 3857 // otherwise see if there is an Agent_OnLoad 3858 if (on_load_entry == NULL) { 3859 on_load_entry = lookup_agent_on_load(agent); 3860 if (on_load_entry != NULL) { 3861 // switch it to the agent list -- so that Agent_OnLoad will be called, 3862 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3863 Arguments::convert_library_to_agent(agent); 3864 } else { 3865 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3866 } 3867 } 3868 } 3869 } 3870 3871 // Create agents for -agentlib: -agentpath: and converted -Xrun 3872 // Invokes Agent_OnLoad 3873 // Called very early -- before JavaThreads exist 3874 void Threads::create_vm_init_agents() { 3875 extern struct JavaVM_ main_vm; 3876 AgentLibrary* agent; 3877 3878 JvmtiExport::enter_onload_phase(); 3879 3880 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3881 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3882 3883 if (on_load_entry != NULL) { 3884 // Invoke the Agent_OnLoad function 3885 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3886 if (err != JNI_OK) { 3887 vm_exit_during_initialization("agent library failed to init", agent->name()); 3888 } 3889 } else { 3890 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3891 } 3892 } 3893 JvmtiExport::enter_primordial_phase(); 3894 } 3895 3896 extern "C" { 3897 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3898 } 3899 3900 void Threads::shutdown_vm_agents() { 3901 // Send any Agent_OnUnload notifications 3902 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3903 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3904 extern struct JavaVM_ main_vm; 3905 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3906 3907 // Find the Agent_OnUnload function. 3908 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3909 os::find_agent_function(agent, 3910 false, 3911 on_unload_symbols, 3912 num_symbol_entries)); 3913 3914 // Invoke the Agent_OnUnload function 3915 if (unload_entry != NULL) { 3916 JavaThread* thread = JavaThread::current(); 3917 ThreadToNativeFromVM ttn(thread); 3918 HandleMark hm(thread); 3919 (*unload_entry)(&main_vm); 3920 } 3921 } 3922 } 3923 3924 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3925 // Invokes JVM_OnLoad 3926 void Threads::create_vm_init_libraries() { 3927 extern struct JavaVM_ main_vm; 3928 AgentLibrary* agent; 3929 3930 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3931 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3932 3933 if (on_load_entry != NULL) { 3934 // Invoke the JVM_OnLoad function 3935 JavaThread* thread = JavaThread::current(); 3936 ThreadToNativeFromVM ttn(thread); 3937 HandleMark hm(thread); 3938 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3939 if (err != JNI_OK) { 3940 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3941 } 3942 } else { 3943 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3944 } 3945 } 3946 } 3947 3948 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3949 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3950 3951 JavaThread* java_thread = NULL; 3952 // Sequential search for now. Need to do better optimization later. 3953 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3954 oop tobj = thread->threadObj(); 3955 if (!thread->is_exiting() && 3956 tobj != NULL && 3957 java_tid == java_lang_Thread::thread_id(tobj)) { 3958 java_thread = thread; 3959 break; 3960 } 3961 } 3962 return java_thread; 3963 } 3964 3965 3966 // Last thread running calls java.lang.Shutdown.shutdown() 3967 void JavaThread::invoke_shutdown_hooks() { 3968 HandleMark hm(this); 3969 3970 // We could get here with a pending exception, if so clear it now. 3971 if (this->has_pending_exception()) { 3972 this->clear_pending_exception(); 3973 } 3974 3975 EXCEPTION_MARK; 3976 Klass* k = 3977 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3978 THREAD); 3979 if (k != NULL) { 3980 // SystemDictionary::resolve_or_null will return null if there was 3981 // an exception. If we cannot load the Shutdown class, just don't 3982 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3983 // and finalizers (if runFinalizersOnExit is set) won't be run. 3984 // Note that if a shutdown hook was registered or runFinalizersOnExit 3985 // was called, the Shutdown class would have already been loaded 3986 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3987 instanceKlassHandle shutdown_klass (THREAD, k); 3988 JavaValue result(T_VOID); 3989 JavaCalls::call_static(&result, 3990 shutdown_klass, 3991 vmSymbols::shutdown_method_name(), 3992 vmSymbols::void_method_signature(), 3993 THREAD); 3994 } 3995 CLEAR_PENDING_EXCEPTION; 3996 } 3997 3998 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3999 // the program falls off the end of main(). Another VM exit path is through 4000 // vm_exit() when the program calls System.exit() to return a value or when 4001 // there is a serious error in VM. The two shutdown paths are not exactly 4002 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 4003 // and VM_Exit op at VM level. 4004 // 4005 // Shutdown sequence: 4006 // + Shutdown native memory tracking if it is on 4007 // + Wait until we are the last non-daemon thread to execute 4008 // <-- every thing is still working at this moment --> 4009 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 4010 // shutdown hooks, run finalizers if finalization-on-exit 4011 // + Call before_exit(), prepare for VM exit 4012 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 4013 // currently the only user of this mechanism is File.deleteOnExit()) 4014 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 4015 // post thread end and vm death events to JVMTI, 4016 // stop signal thread 4017 // + Call JavaThread::exit(), it will: 4018 // > release JNI handle blocks, remove stack guard pages 4019 // > remove this thread from Threads list 4020 // <-- no more Java code from this thread after this point --> 4021 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 4022 // the compiler threads at safepoint 4023 // <-- do not use anything that could get blocked by Safepoint --> 4024 // + Disable tracing at JNI/JVM barriers 4025 // + Set _vm_exited flag for threads that are still running native code 4026 // + Delete this thread 4027 // + Call exit_globals() 4028 // > deletes tty 4029 // > deletes PerfMemory resources 4030 // + Return to caller 4031 4032 bool Threads::destroy_vm() { 4033 JavaThread* thread = JavaThread::current(); 4034 4035 #ifdef ASSERT 4036 _vm_complete = false; 4037 #endif 4038 // Wait until we are the last non-daemon thread to execute 4039 { MutexLocker nu(Threads_lock); 4040 while (Threads::number_of_non_daemon_threads() > 1) 4041 // This wait should make safepoint checks, wait without a timeout, 4042 // and wait as a suspend-equivalent condition. 4043 // 4044 // Note: If the FlatProfiler is running and this thread is waiting 4045 // for another non-daemon thread to finish, then the FlatProfiler 4046 // is waiting for the external suspend request on this thread to 4047 // complete. wait_for_ext_suspend_completion() will eventually 4048 // timeout, but that takes time. Making this wait a suspend- 4049 // equivalent condition solves that timeout problem. 4050 // 4051 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 4052 Mutex::_as_suspend_equivalent_flag); 4053 } 4054 4055 // Hang forever on exit if we are reporting an error. 4056 if (ShowMessageBoxOnError && is_error_reported()) { 4057 os::infinite_sleep(); 4058 } 4059 os::wait_for_keypress_at_exit(); 4060 4061 // run Java level shutdown hooks 4062 thread->invoke_shutdown_hooks(); 4063 4064 before_exit(thread); 4065 4066 thread->exit(true); 4067 4068 // Stop VM thread. 4069 { 4070 // 4945125 The vm thread comes to a safepoint during exit. 4071 // GC vm_operations can get caught at the safepoint, and the 4072 // heap is unparseable if they are caught. Grab the Heap_lock 4073 // to prevent this. The GC vm_operations will not be able to 4074 // queue until after the vm thread is dead. After this point, 4075 // we'll never emerge out of the safepoint before the VM exits. 4076 4077 MutexLocker ml(Heap_lock); 4078 4079 VMThread::wait_for_vm_thread_exit(); 4080 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4081 VMThread::destroy(); 4082 } 4083 4084 // clean up ideal graph printers 4085 #if defined(COMPILER2) && !defined(PRODUCT) 4086 IdealGraphPrinter::clean_up(); 4087 #endif 4088 4089 // Now, all Java threads are gone except daemon threads. Daemon threads 4090 // running Java code or in VM are stopped by the Safepoint. However, 4091 // daemon threads executing native code are still running. But they 4092 // will be stopped at native=>Java/VM barriers. Note that we can't 4093 // simply kill or suspend them, as it is inherently deadlock-prone. 4094 4095 VM_Exit::set_vm_exited(); 4096 4097 notify_vm_shutdown(); 4098 4099 delete thread; 4100 4101 #if INCLUDE_JVMCI 4102 if (JVMCICounterSize > 0) { 4103 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters); 4104 } 4105 #endif 4106 4107 // exit_globals() will delete tty 4108 exit_globals(); 4109 4110 LogConfiguration::finalize(); 4111 4112 return true; 4113 } 4114 4115 4116 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4117 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4118 return is_supported_jni_version(version); 4119 } 4120 4121 4122 jboolean Threads::is_supported_jni_version(jint version) { 4123 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4124 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4125 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4126 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4127 if (version == JNI_VERSION_9) return JNI_TRUE; 4128 return JNI_FALSE; 4129 } 4130 4131 4132 void Threads::add(JavaThread* p, bool force_daemon) { 4133 // The threads lock must be owned at this point 4134 assert_locked_or_safepoint(Threads_lock); 4135 4136 // See the comment for this method in thread.hpp for its purpose and 4137 // why it is called here. 4138 p->initialize_queues(); 4139 p->set_next(_thread_list); 4140 _thread_list = p; 4141 _number_of_threads++; 4142 oop threadObj = p->threadObj(); 4143 bool daemon = true; 4144 // Bootstrapping problem: threadObj can be null for initial 4145 // JavaThread (or for threads attached via JNI) 4146 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4147 _number_of_non_daemon_threads++; 4148 daemon = false; 4149 } 4150 4151 ThreadService::add_thread(p, daemon); 4152 4153 // Possible GC point. 4154 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p)); 4155 } 4156 4157 void Threads::remove(JavaThread* p) { 4158 // Extra scope needed for Thread_lock, so we can check 4159 // that we do not remove thread without safepoint code notice 4160 { MutexLocker ml(Threads_lock); 4161 4162 assert(includes(p), "p must be present"); 4163 4164 JavaThread* current = _thread_list; 4165 JavaThread* prev = NULL; 4166 4167 while (current != p) { 4168 prev = current; 4169 current = current->next(); 4170 } 4171 4172 if (prev) { 4173 prev->set_next(current->next()); 4174 } else { 4175 _thread_list = p->next(); 4176 } 4177 _number_of_threads--; 4178 oop threadObj = p->threadObj(); 4179 bool daemon = true; 4180 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4181 _number_of_non_daemon_threads--; 4182 daemon = false; 4183 4184 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4185 // on destroy_vm will wake up. 4186 if (number_of_non_daemon_threads() == 1) { 4187 Threads_lock->notify_all(); 4188 } 4189 } 4190 ThreadService::remove_thread(p, daemon); 4191 4192 // Make sure that safepoint code disregard this thread. This is needed since 4193 // the thread might mess around with locks after this point. This can cause it 4194 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4195 // of this thread since it is removed from the queue. 4196 p->set_terminated_value(); 4197 } // unlock Threads_lock 4198 4199 // Since Events::log uses a lock, we grab it outside the Threads_lock 4200 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p)); 4201 } 4202 4203 // Threads_lock must be held when this is called (or must be called during a safepoint) 4204 bool Threads::includes(JavaThread* p) { 4205 assert(Threads_lock->is_locked(), "sanity check"); 4206 ALL_JAVA_THREADS(q) { 4207 if (q == p) { 4208 return true; 4209 } 4210 } 4211 return false; 4212 } 4213 4214 // Operations on the Threads list for GC. These are not explicitly locked, 4215 // but the garbage collector must provide a safe context for them to run. 4216 // In particular, these things should never be called when the Threads_lock 4217 // is held by some other thread. (Note: the Safepoint abstraction also 4218 // uses the Threads_lock to guarantee this property. It also makes sure that 4219 // all threads gets blocked when exiting or starting). 4220 4221 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4222 ALL_JAVA_THREADS(p) { 4223 p->oops_do(f, cld_f, cf); 4224 } 4225 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4226 } 4227 4228 void Threads::change_thread_claim_parity() { 4229 // Set the new claim parity. 4230 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2, 4231 "Not in range."); 4232 _thread_claim_parity++; 4233 if (_thread_claim_parity == 3) _thread_claim_parity = 1; 4234 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2, 4235 "Not in range."); 4236 } 4237 4238 #ifdef ASSERT 4239 void Threads::assert_all_threads_claimed() { 4240 ALL_JAVA_THREADS(p) { 4241 const int thread_parity = p->oops_do_parity(); 4242 assert((thread_parity == _thread_claim_parity), 4243 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity); 4244 } 4245 } 4246 #endif // ASSERT 4247 4248 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4249 int cp = Threads::thread_claim_parity(); 4250 ALL_JAVA_THREADS(p) { 4251 if (p->claim_oops_do(is_par, cp)) { 4252 p->oops_do(f, cld_f, cf); 4253 } 4254 } 4255 VMThread* vmt = VMThread::vm_thread(); 4256 if (vmt->claim_oops_do(is_par, cp)) { 4257 vmt->oops_do(f, cld_f, cf); 4258 } 4259 } 4260 4261 #if INCLUDE_ALL_GCS 4262 // Used by ParallelScavenge 4263 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4264 ALL_JAVA_THREADS(p) { 4265 q->enqueue(new ThreadRootsTask(p)); 4266 } 4267 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4268 } 4269 4270 // Used by Parallel Old 4271 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4272 ALL_JAVA_THREADS(p) { 4273 q->enqueue(new ThreadRootsMarkingTask(p)); 4274 } 4275 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4276 } 4277 #endif // INCLUDE_ALL_GCS 4278 4279 void Threads::nmethods_do(CodeBlobClosure* cf) { 4280 ALL_JAVA_THREADS(p) { 4281 p->nmethods_do(cf); 4282 } 4283 VMThread::vm_thread()->nmethods_do(cf); 4284 } 4285 4286 void Threads::metadata_do(void f(Metadata*)) { 4287 ALL_JAVA_THREADS(p) { 4288 p->metadata_do(f); 4289 } 4290 } 4291 4292 class ThreadHandlesClosure : public ThreadClosure { 4293 void (*_f)(Metadata*); 4294 public: 4295 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4296 virtual void do_thread(Thread* thread) { 4297 thread->metadata_handles_do(_f); 4298 } 4299 }; 4300 4301 void Threads::metadata_handles_do(void f(Metadata*)) { 4302 // Only walk the Handles in Thread. 4303 ThreadHandlesClosure handles_closure(f); 4304 threads_do(&handles_closure); 4305 } 4306 4307 void Threads::deoptimized_wrt_marked_nmethods() { 4308 ALL_JAVA_THREADS(p) { 4309 p->deoptimized_wrt_marked_nmethods(); 4310 } 4311 } 4312 4313 4314 // Get count Java threads that are waiting to enter the specified monitor. 4315 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4316 address monitor, 4317 bool doLock) { 4318 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4319 "must grab Threads_lock or be at safepoint"); 4320 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4321 4322 int i = 0; 4323 { 4324 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4325 ALL_JAVA_THREADS(p) { 4326 if (!p->can_call_java()) continue; 4327 4328 address pending = (address)p->current_pending_monitor(); 4329 if (pending == monitor) { // found a match 4330 if (i < count) result->append(p); // save the first count matches 4331 i++; 4332 } 4333 } 4334 } 4335 return result; 4336 } 4337 4338 4339 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, 4340 bool doLock) { 4341 assert(doLock || 4342 Threads_lock->owned_by_self() || 4343 SafepointSynchronize::is_at_safepoint(), 4344 "must grab Threads_lock or be at safepoint"); 4345 4346 // NULL owner means not locked so we can skip the search 4347 if (owner == NULL) return NULL; 4348 4349 { 4350 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4351 ALL_JAVA_THREADS(p) { 4352 // first, see if owner is the address of a Java thread 4353 if (owner == (address)p) return p; 4354 } 4355 } 4356 // Cannot assert on lack of success here since this function may be 4357 // used by code that is trying to report useful problem information 4358 // like deadlock detection. 4359 if (UseHeavyMonitors) return NULL; 4360 4361 // If we didn't find a matching Java thread and we didn't force use of 4362 // heavyweight monitors, then the owner is the stack address of the 4363 // Lock Word in the owning Java thread's stack. 4364 // 4365 JavaThread* the_owner = NULL; 4366 { 4367 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4368 ALL_JAVA_THREADS(q) { 4369 if (q->is_lock_owned(owner)) { 4370 the_owner = q; 4371 break; 4372 } 4373 } 4374 } 4375 // cannot assert on lack of success here; see above comment 4376 return the_owner; 4377 } 4378 4379 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4380 void Threads::print_on(outputStream* st, bool print_stacks, 4381 bool internal_format, bool print_concurrent_locks) { 4382 char buf[32]; 4383 st->print_raw_cr(os::local_time_string(buf, sizeof(buf))); 4384 4385 st->print_cr("Full thread dump %s (%s %s):", 4386 Abstract_VM_Version::vm_name(), 4387 Abstract_VM_Version::vm_release(), 4388 Abstract_VM_Version::vm_info_string()); 4389 st->cr(); 4390 4391 #if INCLUDE_SERVICES 4392 // Dump concurrent locks 4393 ConcurrentLocksDump concurrent_locks; 4394 if (print_concurrent_locks) { 4395 concurrent_locks.dump_at_safepoint(); 4396 } 4397 #endif // INCLUDE_SERVICES 4398 4399 ALL_JAVA_THREADS(p) { 4400 ResourceMark rm; 4401 p->print_on(st); 4402 if (print_stacks) { 4403 if (internal_format) { 4404 p->trace_stack(); 4405 } else { 4406 p->print_stack_on(st); 4407 } 4408 } 4409 st->cr(); 4410 #if INCLUDE_SERVICES 4411 if (print_concurrent_locks) { 4412 concurrent_locks.print_locks_on(p, st); 4413 } 4414 #endif // INCLUDE_SERVICES 4415 } 4416 4417 VMThread::vm_thread()->print_on(st); 4418 st->cr(); 4419 Universe::heap()->print_gc_threads_on(st); 4420 WatcherThread* wt = WatcherThread::watcher_thread(); 4421 if (wt != NULL) { 4422 wt->print_on(st); 4423 st->cr(); 4424 } 4425 st->flush(); 4426 } 4427 4428 // Threads::print_on_error() is called by fatal error handler. It's possible 4429 // that VM is not at safepoint and/or current thread is inside signal handler. 4430 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4431 // memory (even in resource area), it might deadlock the error handler. 4432 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4433 int buflen) { 4434 bool found_current = false; 4435 st->print_cr("Java Threads: ( => current thread )"); 4436 ALL_JAVA_THREADS(thread) { 4437 bool is_current = (current == thread); 4438 found_current = found_current || is_current; 4439 4440 st->print("%s", is_current ? "=>" : " "); 4441 4442 st->print(PTR_FORMAT, p2i(thread)); 4443 st->print(" "); 4444 thread->print_on_error(st, buf, buflen); 4445 st->cr(); 4446 } 4447 st->cr(); 4448 4449 st->print_cr("Other Threads:"); 4450 if (VMThread::vm_thread()) { 4451 bool is_current = (current == VMThread::vm_thread()); 4452 found_current = found_current || is_current; 4453 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4454 4455 st->print(PTR_FORMAT, p2i(VMThread::vm_thread())); 4456 st->print(" "); 4457 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4458 st->cr(); 4459 } 4460 WatcherThread* wt = WatcherThread::watcher_thread(); 4461 if (wt != NULL) { 4462 bool is_current = (current == wt); 4463 found_current = found_current || is_current; 4464 st->print("%s", is_current ? "=>" : " "); 4465 4466 st->print(PTR_FORMAT, p2i(wt)); 4467 st->print(" "); 4468 wt->print_on_error(st, buf, buflen); 4469 st->cr(); 4470 } 4471 if (!found_current) { 4472 st->cr(); 4473 st->print("=>" PTR_FORMAT " (exited) ", p2i(current)); 4474 current->print_on_error(st, buf, buflen); 4475 st->cr(); 4476 } 4477 st->cr(); 4478 st->print_cr("Threads with active compile tasks:"); 4479 print_threads_compiling(st, buf, buflen); 4480 } 4481 4482 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) { 4483 ALL_JAVA_THREADS(thread) { 4484 if (thread->is_Compiler_thread()) { 4485 CompilerThread* ct = (CompilerThread*) thread; 4486 if (ct->task() != NULL) { 4487 thread->print_name_on_error(st, buf, buflen); 4488 ct->task()->print(st, NULL, true, true); 4489 } 4490 } 4491 } 4492 } 4493 4494 4495 // Internal SpinLock and Mutex 4496 // Based on ParkEvent 4497 4498 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4499 // 4500 // We employ SpinLocks _only for low-contention, fixed-length 4501 // short-duration critical sections where we're concerned 4502 // about native mutex_t or HotSpot Mutex:: latency. 4503 // The mux construct provides a spin-then-block mutual exclusion 4504 // mechanism. 4505 // 4506 // Testing has shown that contention on the ListLock guarding gFreeList 4507 // is common. If we implement ListLock as a simple SpinLock it's common 4508 // for the JVM to devolve to yielding with little progress. This is true 4509 // despite the fact that the critical sections protected by ListLock are 4510 // extremely short. 4511 // 4512 // TODO-FIXME: ListLock should be of type SpinLock. 4513 // We should make this a 1st-class type, integrated into the lock 4514 // hierarchy as leaf-locks. Critically, the SpinLock structure 4515 // should have sufficient padding to avoid false-sharing and excessive 4516 // cache-coherency traffic. 4517 4518 4519 typedef volatile int SpinLockT; 4520 4521 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4522 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4523 return; // normal fast-path return 4524 } 4525 4526 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4527 TEVENT(SpinAcquire - ctx); 4528 int ctr = 0; 4529 int Yields = 0; 4530 for (;;) { 4531 while (*adr != 0) { 4532 ++ctr; 4533 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4534 if (Yields > 5) { 4535 os::naked_short_sleep(1); 4536 } else { 4537 os::naked_yield(); 4538 ++Yields; 4539 } 4540 } else { 4541 SpinPause(); 4542 } 4543 } 4544 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4545 } 4546 } 4547 4548 void Thread::SpinRelease(volatile int * adr) { 4549 assert(*adr != 0, "invariant"); 4550 OrderAccess::fence(); // guarantee at least release consistency. 4551 // Roach-motel semantics. 4552 // It's safe if subsequent LDs and STs float "up" into the critical section, 4553 // but prior LDs and STs within the critical section can't be allowed 4554 // to reorder or float past the ST that releases the lock. 4555 // Loads and stores in the critical section - which appear in program 4556 // order before the store that releases the lock - must also appear 4557 // before the store that releases the lock in memory visibility order. 4558 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4559 // the ST of 0 into the lock-word which releases the lock, so fence 4560 // more than covers this on all platforms. 4561 *adr = 0; 4562 } 4563 4564 // muxAcquire and muxRelease: 4565 // 4566 // * muxAcquire and muxRelease support a single-word lock-word construct. 4567 // The LSB of the word is set IFF the lock is held. 4568 // The remainder of the word points to the head of a singly-linked list 4569 // of threads blocked on the lock. 4570 // 4571 // * The current implementation of muxAcquire-muxRelease uses its own 4572 // dedicated Thread._MuxEvent instance. If we're interested in 4573 // minimizing the peak number of extant ParkEvent instances then 4574 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4575 // as certain invariants were satisfied. Specifically, care would need 4576 // to be taken with regards to consuming unpark() "permits". 4577 // A safe rule of thumb is that a thread would never call muxAcquire() 4578 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4579 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4580 // consume an unpark() permit intended for monitorenter, for instance. 4581 // One way around this would be to widen the restricted-range semaphore 4582 // implemented in park(). Another alternative would be to provide 4583 // multiple instances of the PlatformEvent() for each thread. One 4584 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4585 // 4586 // * Usage: 4587 // -- Only as leaf locks 4588 // -- for short-term locking only as muxAcquire does not perform 4589 // thread state transitions. 4590 // 4591 // Alternatives: 4592 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4593 // but with parking or spin-then-park instead of pure spinning. 4594 // * Use Taura-Oyama-Yonenzawa locks. 4595 // * It's possible to construct a 1-0 lock if we encode the lockword as 4596 // (List,LockByte). Acquire will CAS the full lockword while Release 4597 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4598 // acquiring threads use timers (ParkTimed) to detect and recover from 4599 // the stranding window. Thread/Node structures must be aligned on 256-byte 4600 // boundaries by using placement-new. 4601 // * Augment MCS with advisory back-link fields maintained with CAS(). 4602 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4603 // The validity of the backlinks must be ratified before we trust the value. 4604 // If the backlinks are invalid the exiting thread must back-track through the 4605 // the forward links, which are always trustworthy. 4606 // * Add a successor indication. The LockWord is currently encoded as 4607 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4608 // to provide the usual futile-wakeup optimization. 4609 // See RTStt for details. 4610 // * Consider schedctl.sc_nopreempt to cover the critical section. 4611 // 4612 4613 4614 typedef volatile intptr_t MutexT; // Mux Lock-word 4615 enum MuxBits { LOCKBIT = 1 }; 4616 4617 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4618 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4619 if (w == 0) return; 4620 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4621 return; 4622 } 4623 4624 TEVENT(muxAcquire - Contention); 4625 ParkEvent * const Self = Thread::current()->_MuxEvent; 4626 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4627 for (;;) { 4628 int its = (os::is_MP() ? 100 : 0) + 1; 4629 4630 // Optional spin phase: spin-then-park strategy 4631 while (--its >= 0) { 4632 w = *Lock; 4633 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4634 return; 4635 } 4636 } 4637 4638 Self->reset(); 4639 Self->OnList = intptr_t(Lock); 4640 // The following fence() isn't _strictly necessary as the subsequent 4641 // CAS() both serializes execution and ratifies the fetched *Lock value. 4642 OrderAccess::fence(); 4643 for (;;) { 4644 w = *Lock; 4645 if ((w & LOCKBIT) == 0) { 4646 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4647 Self->OnList = 0; // hygiene - allows stronger asserts 4648 return; 4649 } 4650 continue; // Interference -- *Lock changed -- Just retry 4651 } 4652 assert(w & LOCKBIT, "invariant"); 4653 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4654 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4655 } 4656 4657 while (Self->OnList != 0) { 4658 Self->park(); 4659 } 4660 } 4661 } 4662 4663 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4664 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4665 if (w == 0) return; 4666 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4667 return; 4668 } 4669 4670 TEVENT(muxAcquire - Contention); 4671 ParkEvent * ReleaseAfter = NULL; 4672 if (ev == NULL) { 4673 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4674 } 4675 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4676 for (;;) { 4677 guarantee(ev->OnList == 0, "invariant"); 4678 int its = (os::is_MP() ? 100 : 0) + 1; 4679 4680 // Optional spin phase: spin-then-park strategy 4681 while (--its >= 0) { 4682 w = *Lock; 4683 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4684 if (ReleaseAfter != NULL) { 4685 ParkEvent::Release(ReleaseAfter); 4686 } 4687 return; 4688 } 4689 } 4690 4691 ev->reset(); 4692 ev->OnList = intptr_t(Lock); 4693 // The following fence() isn't _strictly necessary as the subsequent 4694 // CAS() both serializes execution and ratifies the fetched *Lock value. 4695 OrderAccess::fence(); 4696 for (;;) { 4697 w = *Lock; 4698 if ((w & LOCKBIT) == 0) { 4699 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4700 ev->OnList = 0; 4701 // We call ::Release while holding the outer lock, thus 4702 // artificially lengthening the critical section. 4703 // Consider deferring the ::Release() until the subsequent unlock(), 4704 // after we've dropped the outer lock. 4705 if (ReleaseAfter != NULL) { 4706 ParkEvent::Release(ReleaseAfter); 4707 } 4708 return; 4709 } 4710 continue; // Interference -- *Lock changed -- Just retry 4711 } 4712 assert(w & LOCKBIT, "invariant"); 4713 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4714 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4715 } 4716 4717 while (ev->OnList != 0) { 4718 ev->park(); 4719 } 4720 } 4721 } 4722 4723 // Release() must extract a successor from the list and then wake that thread. 4724 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4725 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4726 // Release() would : 4727 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4728 // (B) Extract a successor from the private list "in-hand" 4729 // (C) attempt to CAS() the residual back into *Lock over null. 4730 // If there were any newly arrived threads and the CAS() would fail. 4731 // In that case Release() would detach the RATs, re-merge the list in-hand 4732 // with the RATs and repeat as needed. Alternately, Release() might 4733 // detach and extract a successor, but then pass the residual list to the wakee. 4734 // The wakee would be responsible for reattaching and remerging before it 4735 // competed for the lock. 4736 // 4737 // Both "pop" and DMR are immune from ABA corruption -- there can be 4738 // multiple concurrent pushers, but only one popper or detacher. 4739 // This implementation pops from the head of the list. This is unfair, 4740 // but tends to provide excellent throughput as hot threads remain hot. 4741 // (We wake recently run threads first). 4742 // 4743 // All paths through muxRelease() will execute a CAS. 4744 // Release consistency -- We depend on the CAS in muxRelease() to provide full 4745 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4746 // executed within the critical section are complete and globally visible before the 4747 // store (CAS) to the lock-word that releases the lock becomes globally visible. 4748 void Thread::muxRelease(volatile intptr_t * Lock) { 4749 for (;;) { 4750 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4751 assert(w & LOCKBIT, "invariant"); 4752 if (w == LOCKBIT) return; 4753 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4754 assert(List != NULL, "invariant"); 4755 assert(List->OnList == intptr_t(Lock), "invariant"); 4756 ParkEvent * const nxt = List->ListNext; 4757 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4758 4759 // The following CAS() releases the lock and pops the head element. 4760 // The CAS() also ratifies the previously fetched lock-word value. 4761 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4762 continue; 4763 } 4764 List->OnList = 0; 4765 OrderAccess::fence(); 4766 List->unpark(); 4767 return; 4768 } 4769 } 4770 4771 4772 void Threads::verify() { 4773 ALL_JAVA_THREADS(p) { 4774 p->verify(); 4775 } 4776 VMThread* thread = VMThread::vm_thread(); 4777 if (thread != NULL) thread->verify(); 4778 }