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/resourceArea.hpp" 47 #include "memory/universe.inline.hpp" 48 #include "oops/instanceKlass.hpp" 49 #include "oops/objArrayOop.hpp" 50 #include "oops/oop.inline.hpp" 51 #include "oops/symbol.hpp" 52 #include "oops/verifyOopClosure.hpp" 53 #include "prims/jvm_misc.hpp" 54 #include "prims/jvmtiExport.hpp" 55 #include "prims/jvmtiThreadState.hpp" 56 #include "prims/privilegedStack.hpp" 57 #include "runtime/arguments.hpp" 58 #include "runtime/atomic.inline.hpp" 59 #include "runtime/biasedLocking.hpp" 60 #include "runtime/commandLineFlagConstraintList.hpp" 61 #include "runtime/commandLineFlagRangeList.hpp" 62 #include "runtime/deoptimization.hpp" 63 #include "runtime/fprofiler.hpp" 64 #include "runtime/frame.inline.hpp" 65 #include "runtime/globals.hpp" 66 #include "runtime/init.hpp" 67 #include "runtime/interfaceSupport.hpp" 68 #include "runtime/java.hpp" 69 #include "runtime/javaCalls.hpp" 70 #include "runtime/jniPeriodicChecker.hpp" 71 #include "runtime/logTimer.hpp" 72 #include "runtime/memprofiler.hpp" 73 #include "runtime/mutexLocker.hpp" 74 #include "runtime/objectMonitor.hpp" 75 #include "runtime/orderAccess.inline.hpp" 76 #include "runtime/osThread.hpp" 77 #include "runtime/safepoint.hpp" 78 #include "runtime/sharedRuntime.hpp" 79 #include "runtime/statSampler.hpp" 80 #include "runtime/stubRoutines.hpp" 81 #include "runtime/sweeper.hpp" 82 #include "runtime/task.hpp" 83 #include "runtime/thread.inline.hpp" 84 #include "runtime/threadCritical.hpp" 85 #include "runtime/vframe.hpp" 86 #include "runtime/vframeArray.hpp" 87 #include "runtime/vframe_hp.hpp" 88 #include "runtime/vmThread.hpp" 89 #include "runtime/vm_operations.hpp" 90 #include "runtime/vm_version.hpp" 91 #include "services/attachListener.hpp" 92 #include "services/management.hpp" 93 #include "services/memTracker.hpp" 94 #include "services/threadService.hpp" 95 #include "trace/traceMacros.hpp" 96 #include "trace/tracing.hpp" 97 #include "utilities/defaultStream.hpp" 98 #include "utilities/dtrace.hpp" 99 #include "utilities/events.hpp" 100 #include "utilities/macros.hpp" 101 #include "utilities/preserveException.hpp" 102 #if INCLUDE_ALL_GCS 103 #include "gc/cms/concurrentMarkSweepThread.hpp" 104 #include "gc/g1/concurrentMarkThread.inline.hpp" 105 #include "gc/parallel/pcTasks.hpp" 106 #endif // INCLUDE_ALL_GCS 107 #if INCLUDE_JVMCI 108 #include "jvmci/jvmciCompiler.hpp" 109 #include "jvmci/jvmciRuntime.hpp" 110 #endif 111 #ifdef COMPILER1 112 #include "c1/c1_Compiler.hpp" 113 #endif 114 #ifdef COMPILER2 115 #include "opto/c2compiler.hpp" 116 #include "opto/idealGraphPrinter.hpp" 117 #endif 118 #if INCLUDE_RTM_OPT 119 #include "runtime/rtmLocking.hpp" 120 #endif 121 122 #ifdef DTRACE_ENABLED 123 124 // Only bother with this argument setup if dtrace is available 125 126 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 127 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 128 129 #define DTRACE_THREAD_PROBE(probe, javathread) \ 130 { \ 131 ResourceMark rm(this); \ 132 int len = 0; \ 133 const char* name = (javathread)->get_thread_name(); \ 134 len = strlen(name); \ 135 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 136 (char *) name, len, \ 137 java_lang_Thread::thread_id((javathread)->threadObj()), \ 138 (uintptr_t) (javathread)->osthread()->thread_id(), \ 139 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 140 } 141 142 #else // ndef DTRACE_ENABLED 143 144 #define DTRACE_THREAD_PROBE(probe, javathread) 145 146 #endif // ndef DTRACE_ENABLED 147 148 #ifndef USE_LIBRARY_BASED_TLS_ONLY 149 // Current thread is maintained as a thread-local variable 150 THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL; 151 #endif 152 153 // Class hierarchy 154 // - Thread 155 // - VMThread 156 // - WatcherThread 157 // - ConcurrentMarkSweepThread 158 // - JavaThread 159 // - CompilerThread 160 161 // ======= Thread ======== 162 // Support for forcing alignment of thread objects for biased locking 163 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 164 if (UseBiasedLocking) { 165 const int alignment = markOopDesc::biased_lock_alignment; 166 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 167 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 168 : AllocateHeap(aligned_size, flags, CURRENT_PC, 169 AllocFailStrategy::RETURN_NULL); 170 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 171 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 172 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 173 "JavaThread alignment code overflowed allocated storage"); 174 if (aligned_addr != real_malloc_addr) { 175 log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 176 p2i(real_malloc_addr), 177 p2i(aligned_addr)); 178 } 179 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 180 return aligned_addr; 181 } else { 182 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 183 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 184 } 185 } 186 187 void Thread::operator delete(void* p) { 188 if (UseBiasedLocking) { 189 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 190 FreeHeap(real_malloc_addr); 191 } else { 192 FreeHeap(p); 193 } 194 } 195 196 197 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 198 // JavaThread 199 200 201 Thread::Thread() { 202 // stack and get_thread 203 set_stack_base(NULL); 204 set_stack_size(0); 205 set_self_raw_id(0); 206 set_lgrp_id(-1); 207 DEBUG_ONLY(clear_suspendible_thread();) 208 209 // allocated data structures 210 set_osthread(NULL); 211 set_resource_area(new (mtThread)ResourceArea()); 212 DEBUG_ONLY(_current_resource_mark = NULL;) 213 set_handle_area(new (mtThread) HandleArea(NULL)); 214 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 215 set_active_handles(NULL); 216 set_free_handle_block(NULL); 217 set_last_handle_mark(NULL); 218 219 // This initial value ==> never claimed. 220 _oops_do_parity = 0; 221 222 // the handle mark links itself to last_handle_mark 223 new HandleMark(this); 224 225 // plain initialization 226 debug_only(_owned_locks = NULL;) 227 debug_only(_allow_allocation_count = 0;) 228 NOT_PRODUCT(_allow_safepoint_count = 0;) 229 NOT_PRODUCT(_skip_gcalot = false;) 230 _jvmti_env_iteration_count = 0; 231 set_allocated_bytes(0); 232 _vm_operation_started_count = 0; 233 _vm_operation_completed_count = 0; 234 _current_pending_monitor = NULL; 235 _current_pending_monitor_is_from_java = true; 236 _current_waiting_monitor = NULL; 237 _num_nested_signal = 0; 238 omFreeList = NULL; 239 omFreeCount = 0; 240 omFreeProvision = 32; 241 omInUseList = NULL; 242 omInUseCount = 0; 243 244 #ifdef ASSERT 245 _visited_for_critical_count = false; 246 #endif 247 248 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, 249 Monitor::_safepoint_check_sometimes); 250 _suspend_flags = 0; 251 252 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 253 _hashStateX = os::random(); 254 _hashStateY = 842502087; 255 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 256 _hashStateW = 273326509; 257 258 _OnTrap = 0; 259 _schedctl = NULL; 260 _Stalled = 0; 261 _TypeTag = 0x2BAD; 262 263 // Many of the following fields are effectively final - immutable 264 // Note that nascent threads can't use the Native Monitor-Mutex 265 // construct until the _MutexEvent is initialized ... 266 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 267 // we might instead use a stack of ParkEvents that we could provision on-demand. 268 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 269 // and ::Release() 270 _ParkEvent = ParkEvent::Allocate(this); 271 _SleepEvent = ParkEvent::Allocate(this); 272 _MutexEvent = ParkEvent::Allocate(this); 273 _MuxEvent = ParkEvent::Allocate(this); 274 275 #ifdef CHECK_UNHANDLED_OOPS 276 if (CheckUnhandledOops) { 277 _unhandled_oops = new UnhandledOops(this); 278 } 279 #endif // CHECK_UNHANDLED_OOPS 280 #ifdef ASSERT 281 if (UseBiasedLocking) { 282 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 283 assert(this == _real_malloc_address || 284 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 285 "bug in forced alignment of thread objects"); 286 } 287 #endif // ASSERT 288 } 289 290 void Thread::initialize_thread_current() { 291 #ifndef USE_LIBRARY_BASED_TLS_ONLY 292 assert(_thr_current == NULL, "Thread::current already initialized"); 293 _thr_current = this; 294 #endif 295 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized"); 296 ThreadLocalStorage::set_thread(this); 297 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 298 } 299 300 void Thread::clear_thread_current() { 301 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 302 #ifndef USE_LIBRARY_BASED_TLS_ONLY 303 _thr_current = NULL; 304 #endif 305 ThreadLocalStorage::set_thread(NULL); 306 } 307 308 void Thread::record_stack_base_and_size() { 309 set_stack_base(os::current_stack_base()); 310 set_stack_size(os::current_stack_size()); 311 // CR 7190089: on Solaris, primordial thread's stack is adjusted 312 // in initialize_thread(). Without the adjustment, stack size is 313 // incorrect if stack is set to unlimited (ulimit -s unlimited). 314 // So far, only Solaris has real implementation of initialize_thread(). 315 // 316 // set up any platform-specific state. 317 os::initialize_thread(this); 318 319 // Set stack limits after thread is initialized. 320 if (is_Java_thread()) { 321 ((JavaThread*) this)->set_stack_overflow_limit(); 322 ((JavaThread*) this)->set_reserved_stack_activation(stack_base()); 323 } 324 #if INCLUDE_NMT 325 // record thread's native stack, stack grows downward 326 MemTracker::record_thread_stack(stack_end(), stack_size()); 327 #endif // INCLUDE_NMT 328 log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: " 329 PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).", 330 os::current_thread_id(), p2i(stack_base() - stack_size()), 331 p2i(stack_base()), stack_size()/1024); 332 } 333 334 335 Thread::~Thread() { 336 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 337 ObjectSynchronizer::omFlush(this); 338 339 EVENT_THREAD_DESTRUCT(this); 340 341 // stack_base can be NULL if the thread is never started or exited before 342 // record_stack_base_and_size called. Although, we would like to ensure 343 // that all started threads do call record_stack_base_and_size(), there is 344 // not proper way to enforce that. 345 #if INCLUDE_NMT 346 if (_stack_base != NULL) { 347 MemTracker::release_thread_stack(stack_end(), stack_size()); 348 #ifdef ASSERT 349 set_stack_base(NULL); 350 #endif 351 } 352 #endif // INCLUDE_NMT 353 354 // deallocate data structures 355 delete resource_area(); 356 // since the handle marks are using the handle area, we have to deallocated the root 357 // handle mark before deallocating the thread's handle area, 358 assert(last_handle_mark() != NULL, "check we have an element"); 359 delete last_handle_mark(); 360 assert(last_handle_mark() == NULL, "check we have reached the end"); 361 362 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 363 // We NULL out the fields for good hygiene. 364 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 365 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 366 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 367 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 368 369 delete handle_area(); 370 delete metadata_handles(); 371 372 // osthread() can be NULL, if creation of thread failed. 373 if (osthread() != NULL) os::free_thread(osthread()); 374 375 delete _SR_lock; 376 377 // clear Thread::current if thread is deleting itself. 378 // Needed to ensure JNI correctly detects non-attached threads. 379 if (this == Thread::current()) { 380 clear_thread_current(); 381 } 382 383 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 384 } 385 386 // NOTE: dummy function for assertion purpose. 387 void Thread::run() { 388 ShouldNotReachHere(); 389 } 390 391 #ifdef ASSERT 392 // Private method to check for dangling thread pointer 393 void check_for_dangling_thread_pointer(Thread *thread) { 394 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 395 "possibility of dangling Thread pointer"); 396 } 397 #endif 398 399 ThreadPriority Thread::get_priority(const Thread* const thread) { 400 ThreadPriority priority; 401 // Can return an error! 402 (void)os::get_priority(thread, priority); 403 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 404 return priority; 405 } 406 407 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 408 debug_only(check_for_dangling_thread_pointer(thread);) 409 // Can return an error! 410 (void)os::set_priority(thread, priority); 411 } 412 413 414 void Thread::start(Thread* thread) { 415 // Start is different from resume in that its safety is guaranteed by context or 416 // being called from a Java method synchronized on the Thread object. 417 if (!DisableStartThread) { 418 if (thread->is_Java_thread()) { 419 // Initialize the thread state to RUNNABLE before starting this thread. 420 // Can not set it after the thread started because we do not know the 421 // exact thread state at that time. It could be in MONITOR_WAIT or 422 // in SLEEPING or some other state. 423 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 424 java_lang_Thread::RUNNABLE); 425 } 426 os::start_thread(thread); 427 } 428 } 429 430 // Enqueue a VM_Operation to do the job for us - sometime later 431 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 432 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 433 VMThread::execute(vm_stop); 434 } 435 436 437 // Check if an external suspend request has completed (or has been 438 // cancelled). Returns true if the thread is externally suspended and 439 // false otherwise. 440 // 441 // The bits parameter returns information about the code path through 442 // the routine. Useful for debugging: 443 // 444 // set in is_ext_suspend_completed(): 445 // 0x00000001 - routine was entered 446 // 0x00000010 - routine return false at end 447 // 0x00000100 - thread exited (return false) 448 // 0x00000200 - suspend request cancelled (return false) 449 // 0x00000400 - thread suspended (return true) 450 // 0x00001000 - thread is in a suspend equivalent state (return true) 451 // 0x00002000 - thread is native and walkable (return true) 452 // 0x00004000 - thread is native_trans and walkable (needed retry) 453 // 454 // set in wait_for_ext_suspend_completion(): 455 // 0x00010000 - routine was entered 456 // 0x00020000 - suspend request cancelled before loop (return false) 457 // 0x00040000 - thread suspended before loop (return true) 458 // 0x00080000 - suspend request cancelled in loop (return false) 459 // 0x00100000 - thread suspended in loop (return true) 460 // 0x00200000 - suspend not completed during retry loop (return false) 461 462 // Helper class for tracing suspend wait debug bits. 463 // 464 // 0x00000100 indicates that the target thread exited before it could 465 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 466 // 0x00080000 each indicate a cancelled suspend request so they don't 467 // count as wait failures either. 468 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 469 470 class TraceSuspendDebugBits : public StackObj { 471 private: 472 JavaThread * jt; 473 bool is_wait; 474 bool called_by_wait; // meaningful when !is_wait 475 uint32_t * bits; 476 477 public: 478 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 479 uint32_t *_bits) { 480 jt = _jt; 481 is_wait = _is_wait; 482 called_by_wait = _called_by_wait; 483 bits = _bits; 484 } 485 486 ~TraceSuspendDebugBits() { 487 if (!is_wait) { 488 #if 1 489 // By default, don't trace bits for is_ext_suspend_completed() calls. 490 // That trace is very chatty. 491 return; 492 #else 493 if (!called_by_wait) { 494 // If tracing for is_ext_suspend_completed() is enabled, then only 495 // trace calls to it from wait_for_ext_suspend_completion() 496 return; 497 } 498 #endif 499 } 500 501 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 502 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 503 MutexLocker ml(Threads_lock); // needed for get_thread_name() 504 ResourceMark rm; 505 506 tty->print_cr( 507 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 508 jt->get_thread_name(), *bits); 509 510 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 511 } 512 } 513 } 514 }; 515 #undef DEBUG_FALSE_BITS 516 517 518 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 519 uint32_t *bits) { 520 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 521 522 bool did_trans_retry = false; // only do thread_in_native_trans retry once 523 bool do_trans_retry; // flag to force the retry 524 525 *bits |= 0x00000001; 526 527 do { 528 do_trans_retry = false; 529 530 if (is_exiting()) { 531 // Thread is in the process of exiting. This is always checked 532 // first to reduce the risk of dereferencing a freed JavaThread. 533 *bits |= 0x00000100; 534 return false; 535 } 536 537 if (!is_external_suspend()) { 538 // Suspend request is cancelled. This is always checked before 539 // is_ext_suspended() to reduce the risk of a rogue resume 540 // confusing the thread that made the suspend request. 541 *bits |= 0x00000200; 542 return false; 543 } 544 545 if (is_ext_suspended()) { 546 // thread is suspended 547 *bits |= 0x00000400; 548 return true; 549 } 550 551 // Now that we no longer do hard suspends of threads running 552 // native code, the target thread can be changing thread state 553 // while we are in this routine: 554 // 555 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 556 // 557 // We save a copy of the thread state as observed at this moment 558 // and make our decision about suspend completeness based on the 559 // copy. This closes the race where the thread state is seen as 560 // _thread_in_native_trans in the if-thread_blocked check, but is 561 // seen as _thread_blocked in if-thread_in_native_trans check. 562 JavaThreadState save_state = thread_state(); 563 564 if (save_state == _thread_blocked && is_suspend_equivalent()) { 565 // If the thread's state is _thread_blocked and this blocking 566 // condition is known to be equivalent to a suspend, then we can 567 // consider the thread to be externally suspended. This means that 568 // the code that sets _thread_blocked has been modified to do 569 // self-suspension if the blocking condition releases. We also 570 // used to check for CONDVAR_WAIT here, but that is now covered by 571 // the _thread_blocked with self-suspension check. 572 // 573 // Return true since we wouldn't be here unless there was still an 574 // external suspend request. 575 *bits |= 0x00001000; 576 return true; 577 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 578 // Threads running native code will self-suspend on native==>VM/Java 579 // transitions. If its stack is walkable (should always be the case 580 // unless this function is called before the actual java_suspend() 581 // call), then the wait is done. 582 *bits |= 0x00002000; 583 return true; 584 } else if (!called_by_wait && !did_trans_retry && 585 save_state == _thread_in_native_trans && 586 frame_anchor()->walkable()) { 587 // The thread is transitioning from thread_in_native to another 588 // thread state. check_safepoint_and_suspend_for_native_trans() 589 // will force the thread to self-suspend. If it hasn't gotten 590 // there yet we may have caught the thread in-between the native 591 // code check above and the self-suspend. Lucky us. If we were 592 // called by wait_for_ext_suspend_completion(), then it 593 // will be doing the retries so we don't have to. 594 // 595 // Since we use the saved thread state in the if-statement above, 596 // there is a chance that the thread has already transitioned to 597 // _thread_blocked by the time we get here. In that case, we will 598 // make a single unnecessary pass through the logic below. This 599 // doesn't hurt anything since we still do the trans retry. 600 601 *bits |= 0x00004000; 602 603 // Once the thread leaves thread_in_native_trans for another 604 // thread state, we break out of this retry loop. We shouldn't 605 // need this flag to prevent us from getting back here, but 606 // sometimes paranoia is good. 607 did_trans_retry = true; 608 609 // We wait for the thread to transition to a more usable state. 610 for (int i = 1; i <= SuspendRetryCount; i++) { 611 // We used to do an "os::yield_all(i)" call here with the intention 612 // that yielding would increase on each retry. However, the parameter 613 // is ignored on Linux which means the yield didn't scale up. Waiting 614 // on the SR_lock below provides a much more predictable scale up for 615 // the delay. It also provides a simple/direct point to check for any 616 // safepoint requests from the VMThread 617 618 // temporarily drops SR_lock while doing wait with safepoint check 619 // (if we're a JavaThread - the WatcherThread can also call this) 620 // and increase delay with each retry 621 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 622 623 // check the actual thread state instead of what we saved above 624 if (thread_state() != _thread_in_native_trans) { 625 // the thread has transitioned to another thread state so 626 // try all the checks (except this one) one more time. 627 do_trans_retry = true; 628 break; 629 } 630 } // end retry loop 631 632 633 } 634 } while (do_trans_retry); 635 636 *bits |= 0x00000010; 637 return false; 638 } 639 640 // Wait for an external suspend request to complete (or be cancelled). 641 // Returns true if the thread is externally suspended and false otherwise. 642 // 643 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 644 uint32_t *bits) { 645 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 646 false /* !called_by_wait */, bits); 647 648 // local flag copies to minimize SR_lock hold time 649 bool is_suspended; 650 bool pending; 651 uint32_t reset_bits; 652 653 // set a marker so is_ext_suspend_completed() knows we are the caller 654 *bits |= 0x00010000; 655 656 // We use reset_bits to reinitialize the bits value at the top of 657 // each retry loop. This allows the caller to make use of any 658 // unused bits for their own marking purposes. 659 reset_bits = *bits; 660 661 { 662 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 663 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 664 delay, bits); 665 pending = is_external_suspend(); 666 } 667 // must release SR_lock to allow suspension to complete 668 669 if (!pending) { 670 // A cancelled suspend request is the only false return from 671 // is_ext_suspend_completed() that keeps us from entering the 672 // retry loop. 673 *bits |= 0x00020000; 674 return false; 675 } 676 677 if (is_suspended) { 678 *bits |= 0x00040000; 679 return true; 680 } 681 682 for (int i = 1; i <= retries; i++) { 683 *bits = reset_bits; // reinit to only track last retry 684 685 // We used to do an "os::yield_all(i)" call here with the intention 686 // that yielding would increase on each retry. However, the parameter 687 // is ignored on Linux which means the yield didn't scale up. Waiting 688 // on the SR_lock below provides a much more predictable scale up for 689 // the delay. It also provides a simple/direct point to check for any 690 // safepoint requests from the VMThread 691 692 { 693 MutexLocker ml(SR_lock()); 694 // wait with safepoint check (if we're a JavaThread - the WatcherThread 695 // can also call this) and increase delay with each retry 696 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 697 698 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 699 delay, bits); 700 701 // It is possible for the external suspend request to be cancelled 702 // (by a resume) before the actual suspend operation is completed. 703 // Refresh our local copy to see if we still need to wait. 704 pending = is_external_suspend(); 705 } 706 707 if (!pending) { 708 // A cancelled suspend request is the only false return from 709 // is_ext_suspend_completed() that keeps us from staying in the 710 // retry loop. 711 *bits |= 0x00080000; 712 return false; 713 } 714 715 if (is_suspended) { 716 *bits |= 0x00100000; 717 return true; 718 } 719 } // end retry loop 720 721 // thread did not suspend after all our retries 722 *bits |= 0x00200000; 723 return false; 724 } 725 726 #ifndef PRODUCT 727 void JavaThread::record_jump(address target, address instr, const char* file, 728 int line) { 729 730 // This should not need to be atomic as the only way for simultaneous 731 // updates is via interrupts. Even then this should be rare or non-existent 732 // and we don't care that much anyway. 733 734 int index = _jmp_ring_index; 735 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 736 _jmp_ring[index]._target = (intptr_t) target; 737 _jmp_ring[index]._instruction = (intptr_t) instr; 738 _jmp_ring[index]._file = file; 739 _jmp_ring[index]._line = line; 740 } 741 #endif // PRODUCT 742 743 // Called by flat profiler 744 // Callers have already called wait_for_ext_suspend_completion 745 // The assertion for that is currently too complex to put here: 746 bool JavaThread::profile_last_Java_frame(frame* _fr) { 747 bool gotframe = false; 748 // self suspension saves needed state. 749 if (has_last_Java_frame() && _anchor.walkable()) { 750 *_fr = pd_last_frame(); 751 gotframe = true; 752 } 753 return gotframe; 754 } 755 756 void Thread::interrupt(Thread* thread) { 757 debug_only(check_for_dangling_thread_pointer(thread);) 758 os::interrupt(thread); 759 } 760 761 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 762 debug_only(check_for_dangling_thread_pointer(thread);) 763 // Note: If clear_interrupted==false, this simply fetches and 764 // returns the value of the field osthread()->interrupted(). 765 return os::is_interrupted(thread, clear_interrupted); 766 } 767 768 769 // GC Support 770 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 771 jint thread_parity = _oops_do_parity; 772 if (thread_parity != strong_roots_parity) { 773 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 774 if (res == thread_parity) { 775 return true; 776 } else { 777 guarantee(res == strong_roots_parity, "Or else what?"); 778 return false; 779 } 780 } 781 return false; 782 } 783 784 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 785 active_handles()->oops_do(f); 786 // Do oop for ThreadShadow 787 f->do_oop((oop*)&_pending_exception); 788 handle_area()->oops_do(f); 789 } 790 791 void Thread::nmethods_do(CodeBlobClosure* cf) { 792 // no nmethods in a generic thread... 793 } 794 795 void Thread::metadata_handles_do(void f(Metadata*)) { 796 // Only walk the Handles in Thread. 797 if (metadata_handles() != NULL) { 798 for (int i = 0; i< metadata_handles()->length(); i++) { 799 f(metadata_handles()->at(i)); 800 } 801 } 802 } 803 804 void Thread::print_on(outputStream* st) const { 805 // get_priority assumes osthread initialized 806 if (osthread() != NULL) { 807 int os_prio; 808 if (os::get_native_priority(this, &os_prio) == OS_OK) { 809 st->print("os_prio=%d ", os_prio); 810 } 811 st->print("tid=" INTPTR_FORMAT " ", p2i(this)); 812 ext().print_on(st); 813 osthread()->print_on(st); 814 } 815 debug_only(if (WizardMode) print_owned_locks_on(st);) 816 } 817 818 // Thread::print_on_error() is called by fatal error handler. Don't use 819 // any lock or allocate memory. 820 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 821 if (is_VM_thread()) st->print("VMThread"); 822 else if (is_Compiler_thread()) st->print("CompilerThread"); 823 else if (is_Java_thread()) st->print("JavaThread"); 824 else if (is_GC_task_thread()) st->print("GCTaskThread"); 825 else if (is_Watcher_thread()) st->print("WatcherThread"); 826 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 827 else st->print("Thread"); 828 829 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 830 p2i(stack_end()), p2i(stack_base())); 831 832 if (osthread()) { 833 st->print(" [id=%d]", osthread()->thread_id()); 834 } 835 } 836 837 #ifdef ASSERT 838 void Thread::print_owned_locks_on(outputStream* st) const { 839 Monitor *cur = _owned_locks; 840 if (cur == NULL) { 841 st->print(" (no locks) "); 842 } else { 843 st->print_cr(" Locks owned:"); 844 while (cur) { 845 cur->print_on(st); 846 cur = cur->next(); 847 } 848 } 849 } 850 851 static int ref_use_count = 0; 852 853 bool Thread::owns_locks_but_compiled_lock() const { 854 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 855 if (cur != Compile_lock) return true; 856 } 857 return false; 858 } 859 860 861 #endif 862 863 #ifndef PRODUCT 864 865 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 866 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 867 // no threads which allow_vm_block's are held 868 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 869 // Check if current thread is allowed to block at a safepoint 870 if (!(_allow_safepoint_count == 0)) { 871 fatal("Possible safepoint reached by thread that does not allow it"); 872 } 873 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 874 fatal("LEAF method calling lock?"); 875 } 876 877 #ifdef ASSERT 878 if (potential_vm_operation && is_Java_thread() 879 && !Universe::is_bootstrapping()) { 880 // Make sure we do not hold any locks that the VM thread also uses. 881 // This could potentially lead to deadlocks 882 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 883 // Threads_lock is special, since the safepoint synchronization will not start before this is 884 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 885 // since it is used to transfer control between JavaThreads and the VMThread 886 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 887 if ((cur->allow_vm_block() && 888 cur != Threads_lock && 889 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 890 cur != VMOperationRequest_lock && 891 cur != VMOperationQueue_lock) || 892 cur->rank() == Mutex::special) { 893 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 894 } 895 } 896 } 897 898 if (GCALotAtAllSafepoints) { 899 // We could enter a safepoint here and thus have a gc 900 InterfaceSupport::check_gc_alot(); 901 } 902 #endif 903 } 904 #endif 905 906 bool Thread::is_in_stack(address adr) const { 907 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 908 address end = os::current_stack_pointer(); 909 // Allow non Java threads to call this without stack_base 910 if (_stack_base == NULL) return true; 911 if (stack_base() >= adr && adr >= end) return true; 912 913 return false; 914 } 915 916 bool Thread::is_in_usable_stack(address adr) const { 917 size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0; 918 size_t usable_stack_size = _stack_size - stack_guard_size; 919 920 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 921 } 922 923 924 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 925 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 926 // used for compilation in the future. If that change is made, the need for these methods 927 // should be revisited, and they should be removed if possible. 928 929 bool Thread::is_lock_owned(address adr) const { 930 return on_local_stack(adr); 931 } 932 933 bool Thread::set_as_starting_thread() { 934 // NOTE: this must be called inside the main thread. 935 return os::create_main_thread((JavaThread*)this); 936 } 937 938 static void initialize_class(Symbol* class_name, TRAPS) { 939 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 940 InstanceKlass::cast(klass)->initialize(CHECK); 941 } 942 943 944 // Creates the initial ThreadGroup 945 static Handle create_initial_thread_group(TRAPS) { 946 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 947 instanceKlassHandle klass (THREAD, k); 948 949 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 950 { 951 JavaValue result(T_VOID); 952 JavaCalls::call_special(&result, 953 system_instance, 954 klass, 955 vmSymbols::object_initializer_name(), 956 vmSymbols::void_method_signature(), 957 CHECK_NH); 958 } 959 Universe::set_system_thread_group(system_instance()); 960 961 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 962 { 963 JavaValue result(T_VOID); 964 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 965 JavaCalls::call_special(&result, 966 main_instance, 967 klass, 968 vmSymbols::object_initializer_name(), 969 vmSymbols::threadgroup_string_void_signature(), 970 system_instance, 971 string, 972 CHECK_NH); 973 } 974 return main_instance; 975 } 976 977 // Creates the initial Thread 978 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 979 TRAPS) { 980 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 981 instanceKlassHandle klass (THREAD, k); 982 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 983 984 java_lang_Thread::set_thread(thread_oop(), thread); 985 java_lang_Thread::set_priority(thread_oop(), NormPriority); 986 thread->set_threadObj(thread_oop()); 987 988 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 989 990 JavaValue result(T_VOID); 991 JavaCalls::call_special(&result, thread_oop, 992 klass, 993 vmSymbols::object_initializer_name(), 994 vmSymbols::threadgroup_string_void_signature(), 995 thread_group, 996 string, 997 CHECK_NULL); 998 return thread_oop(); 999 } 1000 1001 static void call_initializeSystemClass(TRAPS) { 1002 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1003 instanceKlassHandle klass (THREAD, k); 1004 1005 JavaValue result(T_VOID); 1006 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1007 vmSymbols::void_method_signature(), CHECK); 1008 } 1009 1010 char java_runtime_name[128] = ""; 1011 char java_runtime_version[128] = ""; 1012 1013 // extract the JRE name from java.lang.VersionProps.java_runtime_name 1014 static const char* get_java_runtime_name(TRAPS) { 1015 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1016 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1017 fieldDescriptor fd; 1018 bool found = k != NULL && 1019 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1020 vmSymbols::string_signature(), &fd); 1021 if (found) { 1022 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1023 if (name_oop == NULL) { 1024 return NULL; 1025 } 1026 const char* name = java_lang_String::as_utf8_string(name_oop, 1027 java_runtime_name, 1028 sizeof(java_runtime_name)); 1029 return name; 1030 } else { 1031 return NULL; 1032 } 1033 } 1034 1035 // extract the JRE version from java.lang.VersionProps.java_runtime_version 1036 static const char* get_java_runtime_version(TRAPS) { 1037 Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(), 1038 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1039 fieldDescriptor fd; 1040 bool found = k != NULL && 1041 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1042 vmSymbols::string_signature(), &fd); 1043 if (found) { 1044 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1045 if (name_oop == NULL) { 1046 return NULL; 1047 } 1048 const char* name = java_lang_String::as_utf8_string(name_oop, 1049 java_runtime_version, 1050 sizeof(java_runtime_version)); 1051 return name; 1052 } else { 1053 return NULL; 1054 } 1055 } 1056 1057 // General purpose hook into Java code, run once when the VM is initialized. 1058 // The Java library method itself may be changed independently from the VM. 1059 static void call_postVMInitHook(TRAPS) { 1060 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1061 instanceKlassHandle klass (THREAD, k); 1062 if (klass.not_null()) { 1063 JavaValue result(T_VOID); 1064 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1065 vmSymbols::void_method_signature(), 1066 CHECK); 1067 } 1068 } 1069 1070 static void reset_vm_info_property(TRAPS) { 1071 // the vm info string 1072 ResourceMark rm(THREAD); 1073 const char *vm_info = VM_Version::vm_info_string(); 1074 1075 // java.lang.System class 1076 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1077 instanceKlassHandle klass (THREAD, k); 1078 1079 // setProperty arguments 1080 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1081 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1082 1083 // return value 1084 JavaValue r(T_OBJECT); 1085 1086 // public static String setProperty(String key, String value); 1087 JavaCalls::call_static(&r, 1088 klass, 1089 vmSymbols::setProperty_name(), 1090 vmSymbols::string_string_string_signature(), 1091 key_str, 1092 value_str, 1093 CHECK); 1094 } 1095 1096 1097 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 1098 bool daemon, TRAPS) { 1099 assert(thread_group.not_null(), "thread group should be specified"); 1100 assert(threadObj() == NULL, "should only create Java thread object once"); 1101 1102 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1103 instanceKlassHandle klass (THREAD, k); 1104 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1105 1106 java_lang_Thread::set_thread(thread_oop(), this); 1107 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1108 set_threadObj(thread_oop()); 1109 1110 JavaValue result(T_VOID); 1111 if (thread_name != NULL) { 1112 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1113 // Thread gets assigned specified name and null target 1114 JavaCalls::call_special(&result, 1115 thread_oop, 1116 klass, 1117 vmSymbols::object_initializer_name(), 1118 vmSymbols::threadgroup_string_void_signature(), 1119 thread_group, // Argument 1 1120 name, // Argument 2 1121 THREAD); 1122 } else { 1123 // Thread gets assigned name "Thread-nnn" and null target 1124 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1125 JavaCalls::call_special(&result, 1126 thread_oop, 1127 klass, 1128 vmSymbols::object_initializer_name(), 1129 vmSymbols::threadgroup_runnable_void_signature(), 1130 thread_group, // Argument 1 1131 Handle(), // Argument 2 1132 THREAD); 1133 } 1134 1135 1136 if (daemon) { 1137 java_lang_Thread::set_daemon(thread_oop()); 1138 } 1139 1140 if (HAS_PENDING_EXCEPTION) { 1141 return; 1142 } 1143 1144 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass()); 1145 Handle threadObj(THREAD, this->threadObj()); 1146 1147 JavaCalls::call_special(&result, 1148 thread_group, 1149 group, 1150 vmSymbols::add_method_name(), 1151 vmSymbols::thread_void_signature(), 1152 threadObj, // Arg 1 1153 THREAD); 1154 } 1155 1156 // NamedThread -- non-JavaThread subclasses with multiple 1157 // uniquely named instances should derive from this. 1158 NamedThread::NamedThread() : Thread() { 1159 _name = NULL; 1160 _processed_thread = NULL; 1161 _gc_id = GCId::undefined(); 1162 } 1163 1164 NamedThread::~NamedThread() { 1165 if (_name != NULL) { 1166 FREE_C_HEAP_ARRAY(char, _name); 1167 _name = NULL; 1168 } 1169 } 1170 1171 void NamedThread::set_name(const char* format, ...) { 1172 guarantee(_name == NULL, "Only get to set name once."); 1173 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1174 guarantee(_name != NULL, "alloc failure"); 1175 va_list ap; 1176 va_start(ap, format); 1177 jio_vsnprintf(_name, max_name_len, format, ap); 1178 va_end(ap); 1179 } 1180 1181 void NamedThread::initialize_named_thread() { 1182 set_native_thread_name(name()); 1183 } 1184 1185 void NamedThread::print_on(outputStream* st) const { 1186 st->print("\"%s\" ", name()); 1187 Thread::print_on(st); 1188 st->cr(); 1189 } 1190 1191 1192 // ======= WatcherThread ======== 1193 1194 // The watcher thread exists to simulate timer interrupts. It should 1195 // be replaced by an abstraction over whatever native support for 1196 // timer interrupts exists on the platform. 1197 1198 WatcherThread* WatcherThread::_watcher_thread = NULL; 1199 bool WatcherThread::_startable = false; 1200 volatile bool WatcherThread::_should_terminate = false; 1201 1202 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1203 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1204 if (os::create_thread(this, os::watcher_thread)) { 1205 _watcher_thread = this; 1206 1207 // Set the watcher thread to the highest OS priority which should not be 1208 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1209 // is created. The only normal thread using this priority is the reference 1210 // handler thread, which runs for very short intervals only. 1211 // If the VMThread's priority is not lower than the WatcherThread profiling 1212 // will be inaccurate. 1213 os::set_priority(this, MaxPriority); 1214 if (!DisableStartThread) { 1215 os::start_thread(this); 1216 } 1217 } 1218 } 1219 1220 int WatcherThread::sleep() const { 1221 // The WatcherThread does not participate in the safepoint protocol 1222 // for the PeriodicTask_lock because it is not a JavaThread. 1223 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1224 1225 if (_should_terminate) { 1226 // check for termination before we do any housekeeping or wait 1227 return 0; // we did not sleep. 1228 } 1229 1230 // remaining will be zero if there are no tasks, 1231 // causing the WatcherThread to sleep until a task is 1232 // enrolled 1233 int remaining = PeriodicTask::time_to_wait(); 1234 int time_slept = 0; 1235 1236 // we expect this to timeout - we only ever get unparked when 1237 // we should terminate or when a new task has been enrolled 1238 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1239 1240 jlong time_before_loop = os::javaTimeNanos(); 1241 1242 while (true) { 1243 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, 1244 remaining); 1245 jlong now = os::javaTimeNanos(); 1246 1247 if (remaining == 0) { 1248 // if we didn't have any tasks we could have waited for a long time 1249 // consider the time_slept zero and reset time_before_loop 1250 time_slept = 0; 1251 time_before_loop = now; 1252 } else { 1253 // need to recalculate since we might have new tasks in _tasks 1254 time_slept = (int) ((now - time_before_loop) / 1000000); 1255 } 1256 1257 // Change to task list or spurious wakeup of some kind 1258 if (timedout || _should_terminate) { 1259 break; 1260 } 1261 1262 remaining = PeriodicTask::time_to_wait(); 1263 if (remaining == 0) { 1264 // Last task was just disenrolled so loop around and wait until 1265 // another task gets enrolled 1266 continue; 1267 } 1268 1269 remaining -= time_slept; 1270 if (remaining <= 0) { 1271 break; 1272 } 1273 } 1274 1275 return time_slept; 1276 } 1277 1278 void WatcherThread::run() { 1279 assert(this == watcher_thread(), "just checking"); 1280 1281 this->record_stack_base_and_size(); 1282 this->set_native_thread_name(this->name()); 1283 this->set_active_handles(JNIHandleBlock::allocate_block()); 1284 while (true) { 1285 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1286 assert(watcher_thread() == this, "thread consistency check"); 1287 1288 // Calculate how long it'll be until the next PeriodicTask work 1289 // should be done, and sleep that amount of time. 1290 int time_waited = sleep(); 1291 1292 if (is_error_reported()) { 1293 // A fatal error has happened, the error handler(VMError::report_and_die) 1294 // should abort JVM after creating an error log file. However in some 1295 // rare cases, the error handler itself might deadlock. Here we try to 1296 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1297 // 1298 // This code is in WatcherThread because WatcherThread wakes up 1299 // periodically so the fatal error handler doesn't need to do anything; 1300 // also because the WatcherThread is less likely to crash than other 1301 // threads. 1302 1303 for (;;) { 1304 if (!ShowMessageBoxOnError 1305 && (OnError == NULL || OnError[0] == '\0') 1306 && Arguments::abort_hook() == NULL) { 1307 os::sleep(this, (jlong)ErrorLogTimeout * 1000, false); // in seconds 1308 fdStream err(defaultStream::output_fd()); 1309 err.print_raw_cr("# [ timer expired, abort... ]"); 1310 // skip atexit/vm_exit/vm_abort hooks 1311 os::die(); 1312 } 1313 1314 // Wake up 5 seconds later, the fatal handler may reset OnError or 1315 // ShowMessageBoxOnError when it is ready to abort. 1316 os::sleep(this, 5 * 1000, false); 1317 } 1318 } 1319 1320 if (_should_terminate) { 1321 // check for termination before posting the next tick 1322 break; 1323 } 1324 1325 PeriodicTask::real_time_tick(time_waited); 1326 } 1327 1328 // Signal that it is terminated 1329 { 1330 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1331 _watcher_thread = NULL; 1332 Terminator_lock->notify(); 1333 } 1334 } 1335 1336 void WatcherThread::start() { 1337 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1338 1339 if (watcher_thread() == NULL && _startable) { 1340 _should_terminate = false; 1341 // Create the single instance of WatcherThread 1342 new WatcherThread(); 1343 } 1344 } 1345 1346 void WatcherThread::make_startable() { 1347 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1348 _startable = true; 1349 } 1350 1351 void WatcherThread::stop() { 1352 { 1353 // Follow normal safepoint aware lock enter protocol since the 1354 // WatcherThread is stopped by another JavaThread. 1355 MutexLocker ml(PeriodicTask_lock); 1356 _should_terminate = true; 1357 1358 WatcherThread* watcher = watcher_thread(); 1359 if (watcher != NULL) { 1360 // unpark the WatcherThread so it can see that it should terminate 1361 watcher->unpark(); 1362 } 1363 } 1364 1365 MutexLocker mu(Terminator_lock); 1366 1367 while (watcher_thread() != NULL) { 1368 // This wait should make safepoint checks, wait without a timeout, 1369 // and wait as a suspend-equivalent condition. 1370 // 1371 // Note: If the FlatProfiler is running, then this thread is waiting 1372 // for the WatcherThread to terminate and the WatcherThread, via the 1373 // FlatProfiler task, is waiting for the external suspend request on 1374 // this thread to complete. wait_for_ext_suspend_completion() will 1375 // eventually timeout, but that takes time. Making this wait a 1376 // suspend-equivalent condition solves that timeout problem. 1377 // 1378 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1379 Mutex::_as_suspend_equivalent_flag); 1380 } 1381 } 1382 1383 void WatcherThread::unpark() { 1384 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1385 PeriodicTask_lock->notify(); 1386 } 1387 1388 void WatcherThread::print_on(outputStream* st) const { 1389 st->print("\"%s\" ", name()); 1390 Thread::print_on(st); 1391 st->cr(); 1392 } 1393 1394 // ======= JavaThread ======== 1395 1396 #if INCLUDE_JVMCI 1397 1398 jlong* JavaThread::_jvmci_old_thread_counters; 1399 1400 bool jvmci_counters_include(JavaThread* thread) { 1401 oop threadObj = thread->threadObj(); 1402 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); 1403 } 1404 1405 void JavaThread::collect_counters(typeArrayOop array) { 1406 if (JVMCICounterSize > 0) { 1407 MutexLocker tl(Threads_lock); 1408 for (int i = 0; i < array->length(); i++) { 1409 array->long_at_put(i, _jvmci_old_thread_counters[i]); 1410 } 1411 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) { 1412 if (jvmci_counters_include(tp)) { 1413 for (int i = 0; i < array->length(); i++) { 1414 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]); 1415 } 1416 } 1417 } 1418 } 1419 } 1420 1421 #endif // INCLUDE_JVMCI 1422 1423 // A JavaThread is a normal Java thread 1424 1425 void JavaThread::initialize() { 1426 // Initialize fields 1427 1428 set_saved_exception_pc(NULL); 1429 set_threadObj(NULL); 1430 _anchor.clear(); 1431 set_entry_point(NULL); 1432 set_jni_functions(jni_functions()); 1433 set_callee_target(NULL); 1434 set_vm_result(NULL); 1435 set_vm_result_2(NULL); 1436 set_vframe_array_head(NULL); 1437 set_vframe_array_last(NULL); 1438 set_deferred_locals(NULL); 1439 set_deopt_mark(NULL); 1440 set_deopt_nmethod(NULL); 1441 clear_must_deopt_id(); 1442 set_monitor_chunks(NULL); 1443 set_next(NULL); 1444 set_thread_state(_thread_new); 1445 _terminated = _not_terminated; 1446 _privileged_stack_top = NULL; 1447 _array_for_gc = NULL; 1448 _suspend_equivalent = false; 1449 _in_deopt_handler = 0; 1450 _doing_unsafe_access = false; 1451 _stack_guard_state = stack_guard_unused; 1452 #if INCLUDE_JVMCI 1453 _pending_monitorenter = false; 1454 _pending_deoptimization = -1; 1455 _pending_failed_speculation = NULL; 1456 _pending_transfer_to_interpreter = false; 1457 _jvmci._alternate_call_target = NULL; 1458 assert(_jvmci._implicit_exception_pc == NULL, "must be"); 1459 if (JVMCICounterSize > 0) { 1460 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 1461 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize); 1462 } else { 1463 _jvmci_counters = NULL; 1464 } 1465 #endif // INCLUDE_JVMCI 1466 _reserved_stack_activation = NULL; // stack base not known yet 1467 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1468 _exception_pc = 0; 1469 _exception_handler_pc = 0; 1470 _is_method_handle_return = 0; 1471 _jvmti_thread_state= NULL; 1472 _should_post_on_exceptions_flag = JNI_FALSE; 1473 _jvmti_get_loaded_classes_closure = NULL; 1474 _interp_only_mode = 0; 1475 _special_runtime_exit_condition = _no_async_condition; 1476 _pending_async_exception = NULL; 1477 _thread_stat = NULL; 1478 _thread_stat = new ThreadStatistics(); 1479 _blocked_on_compilation = false; 1480 _jni_active_critical = 0; 1481 _pending_jni_exception_check_fn = NULL; 1482 _do_not_unlock_if_synchronized = false; 1483 _cached_monitor_info = NULL; 1484 _parker = Parker::Allocate(this); 1485 1486 #ifndef PRODUCT 1487 _jmp_ring_index = 0; 1488 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1489 record_jump(NULL, NULL, NULL, 0); 1490 } 1491 #endif // PRODUCT 1492 1493 set_thread_profiler(NULL); 1494 if (FlatProfiler::is_active()) { 1495 // This is where we would decide to either give each thread it's own profiler 1496 // or use one global one from FlatProfiler, 1497 // or up to some count of the number of profiled threads, etc. 1498 ThreadProfiler* pp = new ThreadProfiler(); 1499 pp->engage(); 1500 set_thread_profiler(pp); 1501 } 1502 1503 // Setup safepoint state info for this thread 1504 ThreadSafepointState::create(this); 1505 1506 debug_only(_java_call_counter = 0); 1507 1508 // JVMTI PopFrame support 1509 _popframe_condition = popframe_inactive; 1510 _popframe_preserved_args = NULL; 1511 _popframe_preserved_args_size = 0; 1512 _frames_to_pop_failed_realloc = 0; 1513 1514 pd_initialize(); 1515 } 1516 1517 #if INCLUDE_ALL_GCS 1518 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1519 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1520 #endif // INCLUDE_ALL_GCS 1521 1522 JavaThread::JavaThread(bool is_attaching_via_jni) : 1523 Thread() 1524 #if INCLUDE_ALL_GCS 1525 , _satb_mark_queue(&_satb_mark_queue_set), 1526 _dirty_card_queue(&_dirty_card_queue_set) 1527 #endif // INCLUDE_ALL_GCS 1528 { 1529 initialize(); 1530 if (is_attaching_via_jni) { 1531 _jni_attach_state = _attaching_via_jni; 1532 } else { 1533 _jni_attach_state = _not_attaching_via_jni; 1534 } 1535 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1536 } 1537 1538 bool JavaThread::reguard_stack(address cur_sp) { 1539 if (_stack_guard_state != stack_guard_yellow_reserved_disabled 1540 && _stack_guard_state != stack_guard_reserved_disabled) { 1541 return true; // Stack already guarded or guard pages not needed. 1542 } 1543 1544 if (register_stack_overflow()) { 1545 // For those architectures which have separate register and 1546 // memory stacks, we must check the register stack to see if 1547 // it has overflowed. 1548 return false; 1549 } 1550 1551 // Java code never executes within the yellow zone: the latter is only 1552 // there to provoke an exception during stack banging. If java code 1553 // is executing there, either StackShadowPages should be larger, or 1554 // some exception code in c1, c2 or the interpreter isn't unwinding 1555 // when it should. 1556 guarantee(cur_sp > stack_reserved_zone_base(), 1557 "not enough space to reguard - increase StackShadowPages"); 1558 if (_stack_guard_state == stack_guard_yellow_reserved_disabled) { 1559 enable_stack_yellow_reserved_zone(); 1560 if (reserved_stack_activation() != stack_base()) { 1561 set_reserved_stack_activation(stack_base()); 1562 } 1563 } else if (_stack_guard_state == stack_guard_reserved_disabled) { 1564 set_reserved_stack_activation(stack_base()); 1565 enable_stack_reserved_zone(); 1566 } 1567 return true; 1568 } 1569 1570 bool JavaThread::reguard_stack(void) { 1571 return reguard_stack(os::current_stack_pointer()); 1572 } 1573 1574 1575 void JavaThread::block_if_vm_exited() { 1576 if (_terminated == _vm_exited) { 1577 // _vm_exited is set at safepoint, and Threads_lock is never released 1578 // we will block here forever 1579 Threads_lock->lock_without_safepoint_check(); 1580 ShouldNotReachHere(); 1581 } 1582 } 1583 1584 1585 // Remove this ifdef when C1 is ported to the compiler interface. 1586 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1587 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1588 1589 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1590 Thread() 1591 #if INCLUDE_ALL_GCS 1592 , _satb_mark_queue(&_satb_mark_queue_set), 1593 _dirty_card_queue(&_dirty_card_queue_set) 1594 #endif // INCLUDE_ALL_GCS 1595 { 1596 initialize(); 1597 _jni_attach_state = _not_attaching_via_jni; 1598 set_entry_point(entry_point); 1599 // Create the native thread itself. 1600 // %note runtime_23 1601 os::ThreadType thr_type = os::java_thread; 1602 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1603 os::java_thread; 1604 os::create_thread(this, thr_type, stack_sz); 1605 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1606 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1607 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1608 // the exception consists of creating the exception object & initializing it, initialization 1609 // will leave the VM via a JavaCall and then all locks must be unlocked). 1610 // 1611 // The thread is still suspended when we reach here. Thread must be explicit started 1612 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1613 // by calling Threads:add. The reason why this is not done here, is because the thread 1614 // object must be fully initialized (take a look at JVM_Start) 1615 } 1616 1617 JavaThread::~JavaThread() { 1618 1619 // JSR166 -- return the parker to the free list 1620 Parker::Release(_parker); 1621 _parker = NULL; 1622 1623 // Free any remaining previous UnrollBlock 1624 vframeArray* old_array = vframe_array_last(); 1625 1626 if (old_array != NULL) { 1627 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1628 old_array->set_unroll_block(NULL); 1629 delete old_info; 1630 delete old_array; 1631 } 1632 1633 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1634 if (deferred != NULL) { 1635 // This can only happen if thread is destroyed before deoptimization occurs. 1636 assert(deferred->length() != 0, "empty array!"); 1637 do { 1638 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1639 deferred->remove_at(0); 1640 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1641 delete dlv; 1642 } while (deferred->length() != 0); 1643 delete deferred; 1644 } 1645 1646 // All Java related clean up happens in exit 1647 ThreadSafepointState::destroy(this); 1648 if (_thread_profiler != NULL) delete _thread_profiler; 1649 if (_thread_stat != NULL) delete _thread_stat; 1650 1651 #if INCLUDE_JVMCI 1652 if (JVMCICounterSize > 0) { 1653 if (jvmci_counters_include(this)) { 1654 for (int i = 0; i < JVMCICounterSize; i++) { 1655 _jvmci_old_thread_counters[i] += _jvmci_counters[i]; 1656 } 1657 } 1658 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); 1659 } 1660 #endif // INCLUDE_JVMCI 1661 } 1662 1663 1664 // The first routine called by a new Java thread 1665 void JavaThread::run() { 1666 // initialize thread-local alloc buffer related fields 1667 this->initialize_tlab(); 1668 1669 // used to test validity of stack trace backs 1670 this->record_base_of_stack_pointer(); 1671 1672 // Record real stack base and size. 1673 this->record_stack_base_and_size(); 1674 1675 this->create_stack_guard_pages(); 1676 1677 this->cache_global_variables(); 1678 1679 // Thread is now sufficient initialized to be handled by the safepoint code as being 1680 // in the VM. Change thread state from _thread_new to _thread_in_vm 1681 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1682 1683 assert(JavaThread::current() == this, "sanity check"); 1684 assert(!Thread::current()->owns_locks(), "sanity check"); 1685 1686 DTRACE_THREAD_PROBE(start, this); 1687 1688 // This operation might block. We call that after all safepoint checks for a new thread has 1689 // been completed. 1690 this->set_active_handles(JNIHandleBlock::allocate_block()); 1691 1692 if (JvmtiExport::should_post_thread_life()) { 1693 JvmtiExport::post_thread_start(this); 1694 } 1695 1696 EventThreadStart event; 1697 if (event.should_commit()) { 1698 event.set_thread(THREAD_TRACE_ID(this)); 1699 event.commit(); 1700 } 1701 1702 // We call another function to do the rest so we are sure that the stack addresses used 1703 // from there will be lower than the stack base just computed 1704 thread_main_inner(); 1705 1706 // Note, thread is no longer valid at this point! 1707 } 1708 1709 1710 void JavaThread::thread_main_inner() { 1711 assert(JavaThread::current() == this, "sanity check"); 1712 assert(this->threadObj() != NULL, "just checking"); 1713 1714 // Execute thread entry point unless this thread has a pending exception 1715 // or has been stopped before starting. 1716 // Note: Due to JVM_StopThread we can have pending exceptions already! 1717 if (!this->has_pending_exception() && 1718 !java_lang_Thread::is_stillborn(this->threadObj())) { 1719 { 1720 ResourceMark rm(this); 1721 this->set_native_thread_name(this->get_thread_name()); 1722 } 1723 HandleMark hm(this); 1724 this->entry_point()(this, this); 1725 } 1726 1727 DTRACE_THREAD_PROBE(stop, this); 1728 1729 this->exit(false); 1730 delete this; 1731 } 1732 1733 1734 static void ensure_join(JavaThread* thread) { 1735 // We do not need to grap the Threads_lock, since we are operating on ourself. 1736 Handle threadObj(thread, thread->threadObj()); 1737 assert(threadObj.not_null(), "java thread object must exist"); 1738 ObjectLocker lock(threadObj, thread); 1739 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1740 thread->clear_pending_exception(); 1741 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1742 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1743 // Clear the native thread instance - this makes isAlive return false and allows the join() 1744 // to complete once we've done the notify_all below 1745 java_lang_Thread::set_thread(threadObj(), NULL); 1746 lock.notify_all(thread); 1747 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1748 thread->clear_pending_exception(); 1749 } 1750 1751 1752 // For any new cleanup additions, please check to see if they need to be applied to 1753 // cleanup_failed_attach_current_thread as well. 1754 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1755 assert(this == JavaThread::current(), "thread consistency check"); 1756 1757 HandleMark hm(this); 1758 Handle uncaught_exception(this, this->pending_exception()); 1759 this->clear_pending_exception(); 1760 Handle threadObj(this, this->threadObj()); 1761 assert(threadObj.not_null(), "Java thread object should be created"); 1762 1763 if (get_thread_profiler() != NULL) { 1764 get_thread_profiler()->disengage(); 1765 ResourceMark rm; 1766 get_thread_profiler()->print(get_thread_name()); 1767 } 1768 1769 1770 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1771 { 1772 EXCEPTION_MARK; 1773 1774 CLEAR_PENDING_EXCEPTION; 1775 } 1776 if (!destroy_vm) { 1777 if (uncaught_exception.not_null()) { 1778 EXCEPTION_MARK; 1779 // Call method Thread.dispatchUncaughtException(). 1780 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1781 JavaValue result(T_VOID); 1782 JavaCalls::call_virtual(&result, 1783 threadObj, thread_klass, 1784 vmSymbols::dispatchUncaughtException_name(), 1785 vmSymbols::throwable_void_signature(), 1786 uncaught_exception, 1787 THREAD); 1788 if (HAS_PENDING_EXCEPTION) { 1789 ResourceMark rm(this); 1790 jio_fprintf(defaultStream::error_stream(), 1791 "\nException: %s thrown from the UncaughtExceptionHandler" 1792 " in thread \"%s\"\n", 1793 pending_exception()->klass()->external_name(), 1794 get_thread_name()); 1795 CLEAR_PENDING_EXCEPTION; 1796 } 1797 } 1798 1799 // Called before the java thread exit since we want to read info 1800 // from java_lang_Thread object 1801 EventThreadEnd event; 1802 if (event.should_commit()) { 1803 event.set_thread(THREAD_TRACE_ID(this)); 1804 event.commit(); 1805 } 1806 1807 // Call after last event on thread 1808 EVENT_THREAD_EXIT(this); 1809 1810 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1811 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1812 // is deprecated anyhow. 1813 if (!is_Compiler_thread()) { 1814 int count = 3; 1815 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1816 EXCEPTION_MARK; 1817 JavaValue result(T_VOID); 1818 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1819 JavaCalls::call_virtual(&result, 1820 threadObj, thread_klass, 1821 vmSymbols::exit_method_name(), 1822 vmSymbols::void_method_signature(), 1823 THREAD); 1824 CLEAR_PENDING_EXCEPTION; 1825 } 1826 } 1827 // notify JVMTI 1828 if (JvmtiExport::should_post_thread_life()) { 1829 JvmtiExport::post_thread_end(this); 1830 } 1831 1832 // We have notified the agents that we are exiting, before we go on, 1833 // we must check for a pending external suspend request and honor it 1834 // in order to not surprise the thread that made the suspend request. 1835 while (true) { 1836 { 1837 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1838 if (!is_external_suspend()) { 1839 set_terminated(_thread_exiting); 1840 ThreadService::current_thread_exiting(this); 1841 break; 1842 } 1843 // Implied else: 1844 // Things get a little tricky here. We have a pending external 1845 // suspend request, but we are holding the SR_lock so we 1846 // can't just self-suspend. So we temporarily drop the lock 1847 // and then self-suspend. 1848 } 1849 1850 ThreadBlockInVM tbivm(this); 1851 java_suspend_self(); 1852 1853 // We're done with this suspend request, but we have to loop around 1854 // and check again. Eventually we will get SR_lock without a pending 1855 // external suspend request and will be able to mark ourselves as 1856 // exiting. 1857 } 1858 // no more external suspends are allowed at this point 1859 } else { 1860 // before_exit() has already posted JVMTI THREAD_END events 1861 } 1862 1863 // Notify waiters on thread object. This has to be done after exit() is called 1864 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1865 // group should have the destroyed bit set before waiters are notified). 1866 ensure_join(this); 1867 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1868 1869 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1870 // held by this thread must be released. The spec does not distinguish 1871 // between JNI-acquired and regular Java monitors. We can only see 1872 // regular Java monitors here if monitor enter-exit matching is broken. 1873 // 1874 // Optionally release any monitors for regular JavaThread exits. This 1875 // is provided as a work around for any bugs in monitor enter-exit 1876 // matching. This can be expensive so it is not enabled by default. 1877 // 1878 // ensure_join() ignores IllegalThreadStateExceptions, and so does 1879 // ObjectSynchronizer::release_monitors_owned_by_thread(). 1880 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) { 1881 // Sanity check even though JNI DetachCurrentThread() would have 1882 // returned JNI_ERR if there was a Java frame. JavaThread exit 1883 // should be done executing Java code by the time we get here. 1884 assert(!this->has_last_Java_frame(), 1885 "should not have a Java frame when detaching or exiting"); 1886 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1887 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1888 } 1889 1890 // These things needs to be done while we are still a Java Thread. Make sure that thread 1891 // is in a consistent state, in case GC happens 1892 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1893 1894 if (active_handles() != NULL) { 1895 JNIHandleBlock* block = active_handles(); 1896 set_active_handles(NULL); 1897 JNIHandleBlock::release_block(block); 1898 } 1899 1900 if (free_handle_block() != NULL) { 1901 JNIHandleBlock* block = free_handle_block(); 1902 set_free_handle_block(NULL); 1903 JNIHandleBlock::release_block(block); 1904 } 1905 1906 // These have to be removed while this is still a valid thread. 1907 remove_stack_guard_pages(); 1908 1909 if (UseTLAB) { 1910 tlab().make_parsable(true); // retire TLAB 1911 } 1912 1913 if (JvmtiEnv::environments_might_exist()) { 1914 JvmtiExport::cleanup_thread(this); 1915 } 1916 1917 // We must flush any deferred card marks before removing a thread from 1918 // the list of active threads. 1919 Universe::heap()->flush_deferred_store_barrier(this); 1920 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1921 1922 #if INCLUDE_ALL_GCS 1923 // We must flush the G1-related buffers before removing a thread 1924 // from the list of active threads. We must do this after any deferred 1925 // card marks have been flushed (above) so that any entries that are 1926 // added to the thread's dirty card queue as a result are not lost. 1927 if (UseG1GC) { 1928 flush_barrier_queues(); 1929 } 1930 #endif // INCLUDE_ALL_GCS 1931 1932 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").", 1933 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", 1934 os::current_thread_id()); 1935 1936 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1937 Threads::remove(this); 1938 } 1939 1940 #if INCLUDE_ALL_GCS 1941 // Flush G1-related queues. 1942 void JavaThread::flush_barrier_queues() { 1943 satb_mark_queue().flush(); 1944 dirty_card_queue().flush(); 1945 } 1946 1947 void JavaThread::initialize_queues() { 1948 assert(!SafepointSynchronize::is_at_safepoint(), 1949 "we should not be at a safepoint"); 1950 1951 SATBMarkQueue& satb_queue = satb_mark_queue(); 1952 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1953 // The SATB queue should have been constructed with its active 1954 // field set to false. 1955 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1956 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1957 // If we are creating the thread during a marking cycle, we should 1958 // set the active field of the SATB queue to true. 1959 if (satb_queue_set.is_active()) { 1960 satb_queue.set_active(true); 1961 } 1962 1963 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1964 // The dirty card queue should have been constructed with its 1965 // active field set to true. 1966 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1967 } 1968 #endif // INCLUDE_ALL_GCS 1969 1970 void JavaThread::cleanup_failed_attach_current_thread() { 1971 if (get_thread_profiler() != NULL) { 1972 get_thread_profiler()->disengage(); 1973 ResourceMark rm; 1974 get_thread_profiler()->print(get_thread_name()); 1975 } 1976 1977 if (active_handles() != NULL) { 1978 JNIHandleBlock* block = active_handles(); 1979 set_active_handles(NULL); 1980 JNIHandleBlock::release_block(block); 1981 } 1982 1983 if (free_handle_block() != NULL) { 1984 JNIHandleBlock* block = free_handle_block(); 1985 set_free_handle_block(NULL); 1986 JNIHandleBlock::release_block(block); 1987 } 1988 1989 // These have to be removed while this is still a valid thread. 1990 remove_stack_guard_pages(); 1991 1992 if (UseTLAB) { 1993 tlab().make_parsable(true); // retire TLAB, if any 1994 } 1995 1996 #if INCLUDE_ALL_GCS 1997 if (UseG1GC) { 1998 flush_barrier_queues(); 1999 } 2000 #endif // INCLUDE_ALL_GCS 2001 2002 Threads::remove(this); 2003 delete this; 2004 } 2005 2006 2007 2008 2009 JavaThread* JavaThread::active() { 2010 Thread* thread = Thread::current(); 2011 if (thread->is_Java_thread()) { 2012 return (JavaThread*) thread; 2013 } else { 2014 assert(thread->is_VM_thread(), "this must be a vm thread"); 2015 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2016 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2017 assert(ret->is_Java_thread(), "must be a Java thread"); 2018 return ret; 2019 } 2020 } 2021 2022 bool JavaThread::is_lock_owned(address adr) const { 2023 if (Thread::is_lock_owned(adr)) return true; 2024 2025 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2026 if (chunk->contains(adr)) return true; 2027 } 2028 2029 return false; 2030 } 2031 2032 2033 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2034 chunk->set_next(monitor_chunks()); 2035 set_monitor_chunks(chunk); 2036 } 2037 2038 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2039 guarantee(monitor_chunks() != NULL, "must be non empty"); 2040 if (monitor_chunks() == chunk) { 2041 set_monitor_chunks(chunk->next()); 2042 } else { 2043 MonitorChunk* prev = monitor_chunks(); 2044 while (prev->next() != chunk) prev = prev->next(); 2045 prev->set_next(chunk->next()); 2046 } 2047 } 2048 2049 // JVM support. 2050 2051 // Note: this function shouldn't block if it's called in 2052 // _thread_in_native_trans state (such as from 2053 // check_special_condition_for_native_trans()). 2054 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2055 2056 if (has_last_Java_frame() && has_async_condition()) { 2057 // If we are at a polling page safepoint (not a poll return) 2058 // then we must defer async exception because live registers 2059 // will be clobbered by the exception path. Poll return is 2060 // ok because the call we a returning from already collides 2061 // with exception handling registers and so there is no issue. 2062 // (The exception handling path kills call result registers but 2063 // this is ok since the exception kills the result anyway). 2064 2065 if (is_at_poll_safepoint()) { 2066 // if the code we are returning to has deoptimized we must defer 2067 // the exception otherwise live registers get clobbered on the 2068 // exception path before deoptimization is able to retrieve them. 2069 // 2070 RegisterMap map(this, false); 2071 frame caller_fr = last_frame().sender(&map); 2072 assert(caller_fr.is_compiled_frame(), "what?"); 2073 if (caller_fr.is_deoptimized_frame()) { 2074 log_info(exceptions)("deferred async exception at compiled safepoint"); 2075 return; 2076 } 2077 } 2078 } 2079 2080 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2081 if (condition == _no_async_condition) { 2082 // Conditions have changed since has_special_runtime_exit_condition() 2083 // was called: 2084 // - if we were here only because of an external suspend request, 2085 // then that was taken care of above (or cancelled) so we are done 2086 // - if we were here because of another async request, then it has 2087 // been cleared between the has_special_runtime_exit_condition() 2088 // and now so again we are done 2089 return; 2090 } 2091 2092 // Check for pending async. exception 2093 if (_pending_async_exception != NULL) { 2094 // Only overwrite an already pending exception, if it is not a threadDeath. 2095 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2096 2097 // We cannot call Exceptions::_throw(...) here because we cannot block 2098 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2099 2100 if (log_is_enabled(Info, exceptions)) { 2101 ResourceMark rm; 2102 outputStream* logstream = LogHandle(exceptions)::info_stream(); 2103 logstream->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); 2104 if (has_last_Java_frame()) { 2105 frame f = last_frame(); 2106 logstream->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); 2107 } 2108 logstream->print_cr(" of type: %s", _pending_async_exception->klass()->external_name()); 2109 } 2110 _pending_async_exception = NULL; 2111 clear_has_async_exception(); 2112 } 2113 } 2114 2115 if (check_unsafe_error && 2116 condition == _async_unsafe_access_error && !has_pending_exception()) { 2117 condition = _no_async_condition; // done 2118 switch (thread_state()) { 2119 case _thread_in_vm: { 2120 JavaThread* THREAD = this; 2121 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2122 } 2123 case _thread_in_native: { 2124 ThreadInVMfromNative tiv(this); 2125 JavaThread* THREAD = this; 2126 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2127 } 2128 case _thread_in_Java: { 2129 ThreadInVMfromJava tiv(this); 2130 JavaThread* THREAD = this; 2131 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2132 } 2133 default: 2134 ShouldNotReachHere(); 2135 } 2136 } 2137 2138 assert(condition == _no_async_condition || has_pending_exception() || 2139 (!check_unsafe_error && condition == _async_unsafe_access_error), 2140 "must have handled the async condition, if no exception"); 2141 } 2142 2143 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2144 // 2145 // Check for pending external suspend. Internal suspend requests do 2146 // not use handle_special_runtime_exit_condition(). 2147 // If JNIEnv proxies are allowed, don't self-suspend if the target 2148 // thread is not the current thread. In older versions of jdbx, jdbx 2149 // threads could call into the VM with another thread's JNIEnv so we 2150 // can be here operating on behalf of a suspended thread (4432884). 2151 bool do_self_suspend = is_external_suspend_with_lock(); 2152 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2153 // 2154 // Because thread is external suspended the safepoint code will count 2155 // thread as at a safepoint. This can be odd because we can be here 2156 // as _thread_in_Java which would normally transition to _thread_blocked 2157 // at a safepoint. We would like to mark the thread as _thread_blocked 2158 // before calling java_suspend_self like all other callers of it but 2159 // we must then observe proper safepoint protocol. (We can't leave 2160 // _thread_blocked with a safepoint in progress). However we can be 2161 // here as _thread_in_native_trans so we can't use a normal transition 2162 // constructor/destructor pair because they assert on that type of 2163 // transition. We could do something like: 2164 // 2165 // JavaThreadState state = thread_state(); 2166 // set_thread_state(_thread_in_vm); 2167 // { 2168 // ThreadBlockInVM tbivm(this); 2169 // java_suspend_self() 2170 // } 2171 // set_thread_state(_thread_in_vm_trans); 2172 // if (safepoint) block; 2173 // set_thread_state(state); 2174 // 2175 // but that is pretty messy. Instead we just go with the way the 2176 // code has worked before and note that this is the only path to 2177 // java_suspend_self that doesn't put the thread in _thread_blocked 2178 // mode. 2179 2180 frame_anchor()->make_walkable(this); 2181 java_suspend_self(); 2182 2183 // We might be here for reasons in addition to the self-suspend request 2184 // so check for other async requests. 2185 } 2186 2187 if (check_asyncs) { 2188 check_and_handle_async_exceptions(); 2189 } 2190 } 2191 2192 void JavaThread::send_thread_stop(oop java_throwable) { 2193 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2194 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2195 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2196 2197 // Do not throw asynchronous exceptions against the compiler thread 2198 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2199 if (!can_call_java()) return; 2200 2201 { 2202 // Actually throw the Throwable against the target Thread - however 2203 // only if there is no thread death exception installed already. 2204 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2205 // If the topmost frame is a runtime stub, then we are calling into 2206 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2207 // must deoptimize the caller before continuing, as the compiled exception handler table 2208 // may not be valid 2209 if (has_last_Java_frame()) { 2210 frame f = last_frame(); 2211 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2212 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2213 RegisterMap reg_map(this, UseBiasedLocking); 2214 frame compiled_frame = f.sender(®_map); 2215 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2216 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2217 } 2218 } 2219 } 2220 2221 // Set async. pending exception in thread. 2222 set_pending_async_exception(java_throwable); 2223 2224 if (log_is_enabled(Info, exceptions)) { 2225 ResourceMark rm; 2226 log_info(exceptions)("Pending Async. exception installed of type: %s", 2227 InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2228 } 2229 // for AbortVMOnException flag 2230 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name()); 2231 } 2232 } 2233 2234 2235 // Interrupt thread so it will wake up from a potential wait() 2236 Thread::interrupt(this); 2237 } 2238 2239 // External suspension mechanism. 2240 // 2241 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2242 // to any VM_locks and it is at a transition 2243 // Self-suspension will happen on the transition out of the vm. 2244 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2245 // 2246 // Guarantees on return: 2247 // + Target thread will not execute any new bytecode (that's why we need to 2248 // force a safepoint) 2249 // + Target thread will not enter any new monitors 2250 // 2251 void JavaThread::java_suspend() { 2252 { MutexLocker mu(Threads_lock); 2253 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2254 return; 2255 } 2256 } 2257 2258 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2259 if (!is_external_suspend()) { 2260 // a racing resume has cancelled us; bail out now 2261 return; 2262 } 2263 2264 // suspend is done 2265 uint32_t debug_bits = 0; 2266 // Warning: is_ext_suspend_completed() may temporarily drop the 2267 // SR_lock to allow the thread to reach a stable thread state if 2268 // it is currently in a transient thread state. 2269 if (is_ext_suspend_completed(false /* !called_by_wait */, 2270 SuspendRetryDelay, &debug_bits)) { 2271 return; 2272 } 2273 } 2274 2275 VM_ForceSafepoint vm_suspend; 2276 VMThread::execute(&vm_suspend); 2277 } 2278 2279 // Part II of external suspension. 2280 // A JavaThread self suspends when it detects a pending external suspend 2281 // request. This is usually on transitions. It is also done in places 2282 // where continuing to the next transition would surprise the caller, 2283 // e.g., monitor entry. 2284 // 2285 // Returns the number of times that the thread self-suspended. 2286 // 2287 // Note: DO NOT call java_suspend_self() when you just want to block current 2288 // thread. java_suspend_self() is the second stage of cooperative 2289 // suspension for external suspend requests and should only be used 2290 // to complete an external suspend request. 2291 // 2292 int JavaThread::java_suspend_self() { 2293 int ret = 0; 2294 2295 // we are in the process of exiting so don't suspend 2296 if (is_exiting()) { 2297 clear_external_suspend(); 2298 return ret; 2299 } 2300 2301 assert(_anchor.walkable() || 2302 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2303 "must have walkable stack"); 2304 2305 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2306 2307 assert(!this->is_ext_suspended(), 2308 "a thread trying to self-suspend should not already be suspended"); 2309 2310 if (this->is_suspend_equivalent()) { 2311 // If we are self-suspending as a result of the lifting of a 2312 // suspend equivalent condition, then the suspend_equivalent 2313 // flag is not cleared until we set the ext_suspended flag so 2314 // that wait_for_ext_suspend_completion() returns consistent 2315 // results. 2316 this->clear_suspend_equivalent(); 2317 } 2318 2319 // A racing resume may have cancelled us before we grabbed SR_lock 2320 // above. Or another external suspend request could be waiting for us 2321 // by the time we return from SR_lock()->wait(). The thread 2322 // that requested the suspension may already be trying to walk our 2323 // stack and if we return now, we can change the stack out from under 2324 // it. This would be a "bad thing (TM)" and cause the stack walker 2325 // to crash. We stay self-suspended until there are no more pending 2326 // external suspend requests. 2327 while (is_external_suspend()) { 2328 ret++; 2329 this->set_ext_suspended(); 2330 2331 // _ext_suspended flag is cleared by java_resume() 2332 while (is_ext_suspended()) { 2333 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2334 } 2335 } 2336 2337 return ret; 2338 } 2339 2340 #ifdef ASSERT 2341 // verify the JavaThread has not yet been published in the Threads::list, and 2342 // hence doesn't need protection from concurrent access at this stage 2343 void JavaThread::verify_not_published() { 2344 if (!Threads_lock->owned_by_self()) { 2345 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2346 assert(!Threads::includes(this), 2347 "java thread shouldn't have been published yet!"); 2348 } else { 2349 assert(!Threads::includes(this), 2350 "java thread shouldn't have been published yet!"); 2351 } 2352 } 2353 #endif 2354 2355 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2356 // progress or when _suspend_flags is non-zero. 2357 // Current thread needs to self-suspend if there is a suspend request and/or 2358 // block if a safepoint is in progress. 2359 // Async exception ISN'T checked. 2360 // Note only the ThreadInVMfromNative transition can call this function 2361 // directly and when thread state is _thread_in_native_trans 2362 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2363 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2364 2365 JavaThread *curJT = JavaThread::current(); 2366 bool do_self_suspend = thread->is_external_suspend(); 2367 2368 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2369 2370 // If JNIEnv proxies are allowed, don't self-suspend if the target 2371 // thread is not the current thread. In older versions of jdbx, jdbx 2372 // threads could call into the VM with another thread's JNIEnv so we 2373 // can be here operating on behalf of a suspended thread (4432884). 2374 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2375 JavaThreadState state = thread->thread_state(); 2376 2377 // We mark this thread_blocked state as a suspend-equivalent so 2378 // that a caller to is_ext_suspend_completed() won't be confused. 2379 // The suspend-equivalent state is cleared by java_suspend_self(). 2380 thread->set_suspend_equivalent(); 2381 2382 // If the safepoint code sees the _thread_in_native_trans state, it will 2383 // wait until the thread changes to other thread state. There is no 2384 // guarantee on how soon we can obtain the SR_lock and complete the 2385 // self-suspend request. It would be a bad idea to let safepoint wait for 2386 // too long. Temporarily change the state to _thread_blocked to 2387 // let the VM thread know that this thread is ready for GC. The problem 2388 // of changing thread state is that safepoint could happen just after 2389 // java_suspend_self() returns after being resumed, and VM thread will 2390 // see the _thread_blocked state. We must check for safepoint 2391 // after restoring the state and make sure we won't leave while a safepoint 2392 // is in progress. 2393 thread->set_thread_state(_thread_blocked); 2394 thread->java_suspend_self(); 2395 thread->set_thread_state(state); 2396 // Make sure new state is seen by VM thread 2397 if (os::is_MP()) { 2398 if (UseMembar) { 2399 // Force a fence between the write above and read below 2400 OrderAccess::fence(); 2401 } else { 2402 // Must use this rather than serialization page in particular on Windows 2403 InterfaceSupport::serialize_memory(thread); 2404 } 2405 } 2406 } 2407 2408 if (SafepointSynchronize::do_call_back()) { 2409 // If we are safepointing, then block the caller which may not be 2410 // the same as the target thread (see above). 2411 SafepointSynchronize::block(curJT); 2412 } 2413 2414 if (thread->is_deopt_suspend()) { 2415 thread->clear_deopt_suspend(); 2416 RegisterMap map(thread, false); 2417 frame f = thread->last_frame(); 2418 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2419 f = f.sender(&map); 2420 } 2421 if (f.id() == thread->must_deopt_id()) { 2422 thread->clear_must_deopt_id(); 2423 f.deoptimize(thread); 2424 } else { 2425 fatal("missed deoptimization!"); 2426 } 2427 } 2428 } 2429 2430 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2431 // progress or when _suspend_flags is non-zero. 2432 // Current thread needs to self-suspend if there is a suspend request and/or 2433 // block if a safepoint is in progress. 2434 // Also check for pending async exception (not including unsafe access error). 2435 // Note only the native==>VM/Java barriers can call this function and when 2436 // thread state is _thread_in_native_trans. 2437 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2438 check_safepoint_and_suspend_for_native_trans(thread); 2439 2440 if (thread->has_async_exception()) { 2441 // We are in _thread_in_native_trans state, don't handle unsafe 2442 // access error since that may block. 2443 thread->check_and_handle_async_exceptions(false); 2444 } 2445 } 2446 2447 // This is a variant of the normal 2448 // check_special_condition_for_native_trans with slightly different 2449 // semantics for use by critical native wrappers. It does all the 2450 // normal checks but also performs the transition back into 2451 // thread_in_Java state. This is required so that critical natives 2452 // can potentially block and perform a GC if they are the last thread 2453 // exiting the GCLocker. 2454 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2455 check_special_condition_for_native_trans(thread); 2456 2457 // Finish the transition 2458 thread->set_thread_state(_thread_in_Java); 2459 2460 if (thread->do_critical_native_unlock()) { 2461 ThreadInVMfromJavaNoAsyncException tiv(thread); 2462 GCLocker::unlock_critical(thread); 2463 thread->clear_critical_native_unlock(); 2464 } 2465 } 2466 2467 // We need to guarantee the Threads_lock here, since resumes are not 2468 // allowed during safepoint synchronization 2469 // Can only resume from an external suspension 2470 void JavaThread::java_resume() { 2471 assert_locked_or_safepoint(Threads_lock); 2472 2473 // Sanity check: thread is gone, has started exiting or the thread 2474 // was not externally suspended. 2475 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2476 return; 2477 } 2478 2479 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2480 2481 clear_external_suspend(); 2482 2483 if (is_ext_suspended()) { 2484 clear_ext_suspended(); 2485 SR_lock()->notify_all(); 2486 } 2487 } 2488 2489 size_t JavaThread::_stack_red_zone_size = 0; 2490 size_t JavaThread::_stack_yellow_zone_size = 0; 2491 size_t JavaThread::_stack_reserved_zone_size = 0; 2492 size_t JavaThread::_stack_shadow_zone_size = 0; 2493 2494 void JavaThread::create_stack_guard_pages() { 2495 if (!os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) { return; } 2496 address low_addr = stack_end(); 2497 size_t len = stack_guard_zone_size(); 2498 2499 int allocate = os::allocate_stack_guard_pages(); 2500 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2501 2502 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2503 log_warning(os, thread)("Attempt to allocate stack guard pages failed."); 2504 return; 2505 } 2506 2507 if (os::guard_memory((char *) low_addr, len)) { 2508 _stack_guard_state = stack_guard_enabled; 2509 } else { 2510 log_warning(os, thread)("Attempt to protect stack guard pages failed (" 2511 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2512 if (os::uncommit_memory((char *) low_addr, len)) { 2513 log_warning(os, thread)("Attempt to deallocate stack guard pages failed."); 2514 } 2515 return; 2516 } 2517 2518 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: " 2519 PTR_FORMAT "-" PTR_FORMAT ".", 2520 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2521 2522 } 2523 2524 void JavaThread::remove_stack_guard_pages() { 2525 assert(Thread::current() == this, "from different thread"); 2526 if (_stack_guard_state == stack_guard_unused) return; 2527 address low_addr = stack_end(); 2528 size_t len = stack_guard_zone_size(); 2529 2530 if (os::allocate_stack_guard_pages()) { 2531 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2532 _stack_guard_state = stack_guard_unused; 2533 } else { 2534 log_warning(os, thread)("Attempt to deallocate stack guard pages failed (" 2535 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2536 return; 2537 } 2538 } else { 2539 if (_stack_guard_state == stack_guard_unused) return; 2540 if (os::unguard_memory((char *) low_addr, len)) { 2541 _stack_guard_state = stack_guard_unused; 2542 } else { 2543 log_warning(os, thread)("Attempt to unprotect stack guard pages failed (" 2544 PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len)); 2545 return; 2546 } 2547 } 2548 2549 log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: " 2550 PTR_FORMAT "-" PTR_FORMAT ".", 2551 os::current_thread_id(), p2i(low_addr), p2i(low_addr + len)); 2552 2553 } 2554 2555 void JavaThread::enable_stack_reserved_zone() { 2556 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2557 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2558 2559 // The base notation is from the stack's point of view, growing downward. 2560 // We need to adjust it to work correctly with guard_memory() 2561 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2562 2563 guarantee(base < stack_base(),"Error calculating stack reserved zone"); 2564 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone"); 2565 2566 if (os::guard_memory((char *) base, stack_reserved_zone_size())) { 2567 _stack_guard_state = stack_guard_enabled; 2568 } else { 2569 warning("Attempt to guard stack reserved zone failed."); 2570 } 2571 enable_register_stack_guard(); 2572 } 2573 2574 void JavaThread::disable_stack_reserved_zone() { 2575 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2576 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled"); 2577 2578 // Simply return if called for a thread that does not use guard pages. 2579 if (_stack_guard_state == stack_guard_unused) return; 2580 2581 // The base notation is from the stack's point of view, growing downward. 2582 // We need to adjust it to work correctly with guard_memory() 2583 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2584 2585 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) { 2586 _stack_guard_state = stack_guard_reserved_disabled; 2587 } else { 2588 warning("Attempt to unguard stack reserved zone failed."); 2589 } 2590 disable_register_stack_guard(); 2591 } 2592 2593 void JavaThread::enable_stack_yellow_reserved_zone() { 2594 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2595 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2596 2597 // The base notation is from the stacks point of view, growing downward. 2598 // We need to adjust it to work correctly with guard_memory() 2599 address base = stack_red_zone_base(); 2600 2601 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2602 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2603 2604 if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) { 2605 _stack_guard_state = stack_guard_enabled; 2606 } else { 2607 warning("Attempt to guard stack yellow zone failed."); 2608 } 2609 enable_register_stack_guard(); 2610 } 2611 2612 void JavaThread::disable_stack_yellow_reserved_zone() { 2613 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2614 assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled"); 2615 2616 // Simply return if called for a thread that does not use guard pages. 2617 if (_stack_guard_state == stack_guard_unused) return; 2618 2619 // The base notation is from the stacks point of view, growing downward. 2620 // We need to adjust it to work correctly with guard_memory() 2621 address base = stack_red_zone_base(); 2622 2623 if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) { 2624 _stack_guard_state = stack_guard_yellow_reserved_disabled; 2625 } else { 2626 warning("Attempt to unguard stack yellow zone failed."); 2627 } 2628 disable_register_stack_guard(); 2629 } 2630 2631 void JavaThread::enable_stack_red_zone() { 2632 // The base notation is from the stacks point of view, growing downward. 2633 // We need to adjust it to work correctly with guard_memory() 2634 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2635 address base = stack_red_zone_base() - stack_red_zone_size(); 2636 2637 guarantee(base < stack_base(), "Error calculating stack red zone"); 2638 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2639 2640 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2641 warning("Attempt to guard stack red zone failed."); 2642 } 2643 } 2644 2645 void JavaThread::disable_stack_red_zone() { 2646 // The base notation is from the stacks point of view, growing downward. 2647 // We need to adjust it to work correctly with guard_memory() 2648 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2649 address base = stack_red_zone_base() - stack_red_zone_size(); 2650 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2651 warning("Attempt to unguard stack red zone failed."); 2652 } 2653 } 2654 2655 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2656 // ignore is there is no stack 2657 if (!has_last_Java_frame()) return; 2658 // traverse the stack frames. Starts from top frame. 2659 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2660 frame* fr = fst.current(); 2661 f(fr, fst.register_map()); 2662 } 2663 } 2664 2665 2666 #ifndef PRODUCT 2667 // Deoptimization 2668 // Function for testing deoptimization 2669 void JavaThread::deoptimize() { 2670 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2671 StackFrameStream fst(this, UseBiasedLocking); 2672 bool deopt = false; // Dump stack only if a deopt actually happens. 2673 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2674 // Iterate over all frames in the thread and deoptimize 2675 for (; !fst.is_done(); fst.next()) { 2676 if (fst.current()->can_be_deoptimized()) { 2677 2678 if (only_at) { 2679 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2680 // consists of comma or carriage return separated numbers so 2681 // search for the current bci in that string. 2682 address pc = fst.current()->pc(); 2683 nmethod* nm = (nmethod*) fst.current()->cb(); 2684 ScopeDesc* sd = nm->scope_desc_at(pc); 2685 char buffer[8]; 2686 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2687 size_t len = strlen(buffer); 2688 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2689 while (found != NULL) { 2690 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2691 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2692 // Check that the bci found is bracketed by terminators. 2693 break; 2694 } 2695 found = strstr(found + 1, buffer); 2696 } 2697 if (!found) { 2698 continue; 2699 } 2700 } 2701 2702 if (DebugDeoptimization && !deopt) { 2703 deopt = true; // One-time only print before deopt 2704 tty->print_cr("[BEFORE Deoptimization]"); 2705 trace_frames(); 2706 trace_stack(); 2707 } 2708 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2709 } 2710 } 2711 2712 if (DebugDeoptimization && deopt) { 2713 tty->print_cr("[AFTER Deoptimization]"); 2714 trace_frames(); 2715 } 2716 } 2717 2718 2719 // Make zombies 2720 void JavaThread::make_zombies() { 2721 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2722 if (fst.current()->can_be_deoptimized()) { 2723 // it is a Java nmethod 2724 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2725 nm->make_not_entrant(); 2726 } 2727 } 2728 } 2729 #endif // PRODUCT 2730 2731 2732 void JavaThread::deoptimized_wrt_marked_nmethods() { 2733 if (!has_last_Java_frame()) return; 2734 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2735 StackFrameStream fst(this, UseBiasedLocking); 2736 for (; !fst.is_done(); fst.next()) { 2737 if (fst.current()->should_be_deoptimized()) { 2738 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2739 } 2740 } 2741 } 2742 2743 2744 // If the caller is a NamedThread, then remember, in the current scope, 2745 // the given JavaThread in its _processed_thread field. 2746 class RememberProcessedThread: public StackObj { 2747 NamedThread* _cur_thr; 2748 public: 2749 RememberProcessedThread(JavaThread* jthr) { 2750 Thread* thread = Thread::current(); 2751 if (thread->is_Named_thread()) { 2752 _cur_thr = (NamedThread *)thread; 2753 _cur_thr->set_processed_thread(jthr); 2754 } else { 2755 _cur_thr = NULL; 2756 } 2757 } 2758 2759 ~RememberProcessedThread() { 2760 if (_cur_thr) { 2761 _cur_thr->set_processed_thread(NULL); 2762 } 2763 } 2764 }; 2765 2766 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2767 // Verify that the deferred card marks have been flushed. 2768 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2769 2770 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2771 // since there may be more than one thread using each ThreadProfiler. 2772 2773 // Traverse the GCHandles 2774 Thread::oops_do(f, cld_f, cf); 2775 2776 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);) 2777 2778 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2779 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2780 2781 if (has_last_Java_frame()) { 2782 // Record JavaThread to GC thread 2783 RememberProcessedThread rpt(this); 2784 2785 // Traverse the privileged stack 2786 if (_privileged_stack_top != NULL) { 2787 _privileged_stack_top->oops_do(f); 2788 } 2789 2790 // traverse the registered growable array 2791 if (_array_for_gc != NULL) { 2792 for (int index = 0; index < _array_for_gc->length(); index++) { 2793 f->do_oop(_array_for_gc->adr_at(index)); 2794 } 2795 } 2796 2797 // Traverse the monitor chunks 2798 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2799 chunk->oops_do(f); 2800 } 2801 2802 // Traverse the execution stack 2803 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2804 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2805 } 2806 } 2807 2808 // callee_target is never live across a gc point so NULL it here should 2809 // it still contain a methdOop. 2810 2811 set_callee_target(NULL); 2812 2813 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2814 // If we have deferred set_locals there might be oops waiting to be 2815 // written 2816 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2817 if (list != NULL) { 2818 for (int i = 0; i < list->length(); i++) { 2819 list->at(i)->oops_do(f); 2820 } 2821 } 2822 2823 // Traverse instance variables at the end since the GC may be moving things 2824 // around using this function 2825 f->do_oop((oop*) &_threadObj); 2826 f->do_oop((oop*) &_vm_result); 2827 f->do_oop((oop*) &_exception_oop); 2828 f->do_oop((oop*) &_pending_async_exception); 2829 2830 if (jvmti_thread_state() != NULL) { 2831 jvmti_thread_state()->oops_do(f); 2832 } 2833 } 2834 2835 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2836 Thread::nmethods_do(cf); // (super method is a no-op) 2837 2838 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2839 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2840 2841 if (has_last_Java_frame()) { 2842 // Traverse the execution stack 2843 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2844 fst.current()->nmethods_do(cf); 2845 } 2846 } 2847 } 2848 2849 void JavaThread::metadata_do(void f(Metadata*)) { 2850 if (has_last_Java_frame()) { 2851 // Traverse the execution stack to call f() on the methods in the stack 2852 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2853 fst.current()->metadata_do(f); 2854 } 2855 } else if (is_Compiler_thread()) { 2856 // need to walk ciMetadata in current compile tasks to keep alive. 2857 CompilerThread* ct = (CompilerThread*)this; 2858 if (ct->env() != NULL) { 2859 ct->env()->metadata_do(f); 2860 } 2861 if (ct->task() != NULL) { 2862 ct->task()->metadata_do(f); 2863 } 2864 } 2865 } 2866 2867 // Printing 2868 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2869 switch (_thread_state) { 2870 case _thread_uninitialized: return "_thread_uninitialized"; 2871 case _thread_new: return "_thread_new"; 2872 case _thread_new_trans: return "_thread_new_trans"; 2873 case _thread_in_native: return "_thread_in_native"; 2874 case _thread_in_native_trans: return "_thread_in_native_trans"; 2875 case _thread_in_vm: return "_thread_in_vm"; 2876 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2877 case _thread_in_Java: return "_thread_in_Java"; 2878 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2879 case _thread_blocked: return "_thread_blocked"; 2880 case _thread_blocked_trans: return "_thread_blocked_trans"; 2881 default: return "unknown thread state"; 2882 } 2883 } 2884 2885 #ifndef PRODUCT 2886 void JavaThread::print_thread_state_on(outputStream *st) const { 2887 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2888 }; 2889 void JavaThread::print_thread_state() const { 2890 print_thread_state_on(tty); 2891 } 2892 #endif // PRODUCT 2893 2894 // Called by Threads::print() for VM_PrintThreads operation 2895 void JavaThread::print_on(outputStream *st) const { 2896 st->print("\"%s\" ", get_thread_name()); 2897 oop thread_oop = threadObj(); 2898 if (thread_oop != NULL) { 2899 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2900 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2901 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2902 } 2903 Thread::print_on(st); 2904 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2905 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2906 if (thread_oop != NULL) { 2907 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2908 } 2909 #ifndef PRODUCT 2910 print_thread_state_on(st); 2911 _safepoint_state->print_on(st); 2912 #endif // PRODUCT 2913 if (is_Compiler_thread()) { 2914 CompilerThread* ct = (CompilerThread*)this; 2915 if (ct->task() != NULL) { 2916 st->print(" Compiling: "); 2917 ct->task()->print(st, NULL, true, false); 2918 } else { 2919 st->print(" No compile task"); 2920 } 2921 st->cr(); 2922 } 2923 } 2924 2925 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const { 2926 st->print("%s", get_thread_name_string(buf, buflen)); 2927 } 2928 2929 // Called by fatal error handler. The difference between this and 2930 // JavaThread::print() is that we can't grab lock or allocate memory. 2931 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2932 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2933 oop thread_obj = threadObj(); 2934 if (thread_obj != NULL) { 2935 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2936 } 2937 st->print(" ["); 2938 st->print("%s", _get_thread_state_name(_thread_state)); 2939 if (osthread()) { 2940 st->print(", id=%d", osthread()->thread_id()); 2941 } 2942 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2943 p2i(stack_end()), p2i(stack_base())); 2944 st->print("]"); 2945 return; 2946 } 2947 2948 // Verification 2949 2950 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2951 2952 void JavaThread::verify() { 2953 // Verify oops in the thread. 2954 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2955 2956 // Verify the stack frames. 2957 frames_do(frame_verify); 2958 } 2959 2960 // CR 6300358 (sub-CR 2137150) 2961 // Most callers of this method assume that it can't return NULL but a 2962 // thread may not have a name whilst it is in the process of attaching to 2963 // the VM - see CR 6412693, and there are places where a JavaThread can be 2964 // seen prior to having it's threadObj set (eg JNI attaching threads and 2965 // if vm exit occurs during initialization). These cases can all be accounted 2966 // for such that this method never returns NULL. 2967 const char* JavaThread::get_thread_name() const { 2968 #ifdef ASSERT 2969 // early safepoints can hit while current thread does not yet have TLS 2970 if (!SafepointSynchronize::is_at_safepoint()) { 2971 Thread *cur = Thread::current(); 2972 if (!(cur->is_Java_thread() && cur == this)) { 2973 // Current JavaThreads are allowed to get their own name without 2974 // the Threads_lock. 2975 assert_locked_or_safepoint(Threads_lock); 2976 } 2977 } 2978 #endif // ASSERT 2979 return get_thread_name_string(); 2980 } 2981 2982 // Returns a non-NULL representation of this thread's name, or a suitable 2983 // descriptive string if there is no set name 2984 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2985 const char* name_str; 2986 oop thread_obj = threadObj(); 2987 if (thread_obj != NULL) { 2988 oop name = java_lang_Thread::name(thread_obj); 2989 if (name != NULL) { 2990 if (buf == NULL) { 2991 name_str = java_lang_String::as_utf8_string(name); 2992 } else { 2993 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 2994 } 2995 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2996 name_str = "<no-name - thread is attaching>"; 2997 } else { 2998 name_str = Thread::name(); 2999 } 3000 } else { 3001 name_str = Thread::name(); 3002 } 3003 assert(name_str != NULL, "unexpected NULL thread name"); 3004 return name_str; 3005 } 3006 3007 3008 const char* JavaThread::get_threadgroup_name() const { 3009 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 3010 oop thread_obj = threadObj(); 3011 if (thread_obj != NULL) { 3012 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 3013 if (thread_group != NULL) { 3014 // ThreadGroup.name can be null 3015 return java_lang_ThreadGroup::name(thread_group); 3016 } 3017 } 3018 return NULL; 3019 } 3020 3021 const char* JavaThread::get_parent_name() const { 3022 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 3023 oop thread_obj = threadObj(); 3024 if (thread_obj != NULL) { 3025 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 3026 if (thread_group != NULL) { 3027 oop parent = java_lang_ThreadGroup::parent(thread_group); 3028 if (parent != NULL) { 3029 // ThreadGroup.name can be null 3030 return java_lang_ThreadGroup::name(parent); 3031 } 3032 } 3033 } 3034 return NULL; 3035 } 3036 3037 ThreadPriority JavaThread::java_priority() const { 3038 oop thr_oop = threadObj(); 3039 if (thr_oop == NULL) return NormPriority; // Bootstrapping 3040 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 3041 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 3042 return priority; 3043 } 3044 3045 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 3046 3047 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3048 // Link Java Thread object <-> C++ Thread 3049 3050 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3051 // and put it into a new Handle. The Handle "thread_oop" can then 3052 // be used to pass the C++ thread object to other methods. 3053 3054 // Set the Java level thread object (jthread) field of the 3055 // new thread (a JavaThread *) to C++ thread object using the 3056 // "thread_oop" handle. 3057 3058 // Set the thread field (a JavaThread *) of the 3059 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3060 3061 Handle thread_oop(Thread::current(), 3062 JNIHandles::resolve_non_null(jni_thread)); 3063 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3064 "must be initialized"); 3065 set_threadObj(thread_oop()); 3066 java_lang_Thread::set_thread(thread_oop(), this); 3067 3068 if (prio == NoPriority) { 3069 prio = java_lang_Thread::priority(thread_oop()); 3070 assert(prio != NoPriority, "A valid priority should be present"); 3071 } 3072 3073 // Push the Java priority down to the native thread; needs Threads_lock 3074 Thread::set_priority(this, prio); 3075 3076 prepare_ext(); 3077 3078 // Add the new thread to the Threads list and set it in motion. 3079 // We must have threads lock in order to call Threads::add. 3080 // It is crucial that we do not block before the thread is 3081 // added to the Threads list for if a GC happens, then the java_thread oop 3082 // will not be visited by GC. 3083 Threads::add(this); 3084 } 3085 3086 oop JavaThread::current_park_blocker() { 3087 // Support for JSR-166 locks 3088 oop thread_oop = threadObj(); 3089 if (thread_oop != NULL && 3090 JDK_Version::current().supports_thread_park_blocker()) { 3091 return java_lang_Thread::park_blocker(thread_oop); 3092 } 3093 return NULL; 3094 } 3095 3096 3097 void JavaThread::print_stack_on(outputStream* st) { 3098 if (!has_last_Java_frame()) return; 3099 ResourceMark rm; 3100 HandleMark hm; 3101 3102 RegisterMap reg_map(this); 3103 vframe* start_vf = last_java_vframe(®_map); 3104 int count = 0; 3105 for (vframe* f = start_vf; f; f = f->sender()) { 3106 if (f->is_java_frame()) { 3107 javaVFrame* jvf = javaVFrame::cast(f); 3108 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3109 3110 // Print out lock information 3111 if (JavaMonitorsInStackTrace) { 3112 jvf->print_lock_info_on(st, count); 3113 } 3114 } else { 3115 // Ignore non-Java frames 3116 } 3117 3118 // Bail-out case for too deep stacks 3119 count++; 3120 if (MaxJavaStackTraceDepth == count) return; 3121 } 3122 } 3123 3124 3125 // JVMTI PopFrame support 3126 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3127 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3128 if (in_bytes(size_in_bytes) != 0) { 3129 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3130 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3131 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3132 } 3133 } 3134 3135 void* JavaThread::popframe_preserved_args() { 3136 return _popframe_preserved_args; 3137 } 3138 3139 ByteSize JavaThread::popframe_preserved_args_size() { 3140 return in_ByteSize(_popframe_preserved_args_size); 3141 } 3142 3143 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3144 int sz = in_bytes(popframe_preserved_args_size()); 3145 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3146 return in_WordSize(sz / wordSize); 3147 } 3148 3149 void JavaThread::popframe_free_preserved_args() { 3150 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3151 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3152 _popframe_preserved_args = NULL; 3153 _popframe_preserved_args_size = 0; 3154 } 3155 3156 #ifndef PRODUCT 3157 3158 void JavaThread::trace_frames() { 3159 tty->print_cr("[Describe stack]"); 3160 int frame_no = 1; 3161 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3162 tty->print(" %d. ", frame_no++); 3163 fst.current()->print_value_on(tty, this); 3164 tty->cr(); 3165 } 3166 } 3167 3168 class PrintAndVerifyOopClosure: public OopClosure { 3169 protected: 3170 template <class T> inline void do_oop_work(T* p) { 3171 oop obj = oopDesc::load_decode_heap_oop(p); 3172 if (obj == NULL) return; 3173 tty->print(INTPTR_FORMAT ": ", p2i(p)); 3174 if (obj->is_oop_or_null()) { 3175 if (obj->is_objArray()) { 3176 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); 3177 } else { 3178 obj->print(); 3179 } 3180 } else { 3181 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); 3182 } 3183 tty->cr(); 3184 } 3185 public: 3186 virtual void do_oop(oop* p) { do_oop_work(p); } 3187 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3188 }; 3189 3190 3191 static void oops_print(frame* f, const RegisterMap *map) { 3192 PrintAndVerifyOopClosure print; 3193 f->print_value(); 3194 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3195 } 3196 3197 // Print our all the locations that contain oops and whether they are 3198 // valid or not. This useful when trying to find the oldest frame 3199 // where an oop has gone bad since the frame walk is from youngest to 3200 // oldest. 3201 void JavaThread::trace_oops() { 3202 tty->print_cr("[Trace oops]"); 3203 frames_do(oops_print); 3204 } 3205 3206 3207 #ifdef ASSERT 3208 // Print or validate the layout of stack frames 3209 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3210 ResourceMark rm; 3211 PRESERVE_EXCEPTION_MARK; 3212 FrameValues values; 3213 int frame_no = 0; 3214 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3215 fst.current()->describe(values, ++frame_no); 3216 if (depth == frame_no) break; 3217 } 3218 if (validate_only) { 3219 values.validate(); 3220 } else { 3221 tty->print_cr("[Describe stack layout]"); 3222 values.print(this); 3223 } 3224 } 3225 #endif 3226 3227 void JavaThread::trace_stack_from(vframe* start_vf) { 3228 ResourceMark rm; 3229 int vframe_no = 1; 3230 for (vframe* f = start_vf; f; f = f->sender()) { 3231 if (f->is_java_frame()) { 3232 javaVFrame::cast(f)->print_activation(vframe_no++); 3233 } else { 3234 f->print(); 3235 } 3236 if (vframe_no > StackPrintLimit) { 3237 tty->print_cr("...<more frames>..."); 3238 return; 3239 } 3240 } 3241 } 3242 3243 3244 void JavaThread::trace_stack() { 3245 if (!has_last_Java_frame()) return; 3246 ResourceMark rm; 3247 HandleMark hm; 3248 RegisterMap reg_map(this); 3249 trace_stack_from(last_java_vframe(®_map)); 3250 } 3251 3252 3253 #endif // PRODUCT 3254 3255 3256 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3257 assert(reg_map != NULL, "a map must be given"); 3258 frame f = last_frame(); 3259 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3260 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3261 } 3262 return NULL; 3263 } 3264 3265 3266 Klass* JavaThread::security_get_caller_class(int depth) { 3267 vframeStream vfst(this); 3268 vfst.security_get_caller_frame(depth); 3269 if (!vfst.at_end()) { 3270 return vfst.method()->method_holder(); 3271 } 3272 return NULL; 3273 } 3274 3275 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3276 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3277 CompileBroker::compiler_thread_loop(); 3278 } 3279 3280 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3281 NMethodSweeper::sweeper_loop(); 3282 } 3283 3284 // Create a CompilerThread 3285 CompilerThread::CompilerThread(CompileQueue* queue, 3286 CompilerCounters* counters) 3287 : JavaThread(&compiler_thread_entry) { 3288 _env = NULL; 3289 _log = NULL; 3290 _task = NULL; 3291 _queue = queue; 3292 _counters = counters; 3293 _buffer_blob = NULL; 3294 _compiler = NULL; 3295 3296 #ifndef PRODUCT 3297 _ideal_graph_printer = NULL; 3298 #endif 3299 } 3300 3301 bool CompilerThread::can_call_java() const { 3302 return _compiler != NULL && _compiler->is_jvmci(); 3303 } 3304 3305 // Create sweeper thread 3306 CodeCacheSweeperThread::CodeCacheSweeperThread() 3307 : JavaThread(&sweeper_thread_entry) { 3308 _scanned_nmethod = NULL; 3309 } 3310 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3311 JavaThread::oops_do(f, cld_f, cf); 3312 if (_scanned_nmethod != NULL && cf != NULL) { 3313 // Safepoints can occur when the sweeper is scanning an nmethod so 3314 // process it here to make sure it isn't unloaded in the middle of 3315 // a scan. 3316 cf->do_code_blob(_scanned_nmethod); 3317 } 3318 } 3319 3320 3321 // ======= Threads ======== 3322 3323 // The Threads class links together all active threads, and provides 3324 // operations over all threads. It is protected by its own Mutex 3325 // lock, which is also used in other contexts to protect thread 3326 // operations from having the thread being operated on from exiting 3327 // and going away unexpectedly (e.g., safepoint synchronization) 3328 3329 JavaThread* Threads::_thread_list = NULL; 3330 int Threads::_number_of_threads = 0; 3331 int Threads::_number_of_non_daemon_threads = 0; 3332 int Threads::_return_code = 0; 3333 int Threads::_thread_claim_parity = 0; 3334 size_t JavaThread::_stack_size_at_create = 0; 3335 #ifdef ASSERT 3336 bool Threads::_vm_complete = false; 3337 #endif 3338 3339 // All JavaThreads 3340 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3341 3342 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3343 void Threads::threads_do(ThreadClosure* tc) { 3344 assert_locked_or_safepoint(Threads_lock); 3345 // ALL_JAVA_THREADS iterates through all JavaThreads 3346 ALL_JAVA_THREADS(p) { 3347 tc->do_thread(p); 3348 } 3349 // Someday we could have a table or list of all non-JavaThreads. 3350 // For now, just manually iterate through them. 3351 tc->do_thread(VMThread::vm_thread()); 3352 Universe::heap()->gc_threads_do(tc); 3353 WatcherThread *wt = WatcherThread::watcher_thread(); 3354 // Strictly speaking, the following NULL check isn't sufficient to make sure 3355 // the data for WatcherThread is still valid upon being examined. However, 3356 // considering that WatchThread terminates when the VM is on the way to 3357 // exit at safepoint, the chance of the above is extremely small. The right 3358 // way to prevent termination of WatcherThread would be to acquire 3359 // Terminator_lock, but we can't do that without violating the lock rank 3360 // checking in some cases. 3361 if (wt != NULL) { 3362 tc->do_thread(wt); 3363 } 3364 3365 // If CompilerThreads ever become non-JavaThreads, add them here 3366 } 3367 3368 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3369 TraceStartupTime timer("Initialize java.lang classes"); 3370 3371 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3372 create_vm_init_libraries(); 3373 } 3374 3375 initialize_class(vmSymbols::java_lang_String(), CHECK); 3376 3377 // Inject CompactStrings value after the static initializers for String ran. 3378 java_lang_String::set_compact_strings(CompactStrings); 3379 3380 // Initialize java_lang.System (needed before creating the thread) 3381 initialize_class(vmSymbols::java_lang_System(), CHECK); 3382 // The VM creates & returns objects of this class. Make sure it's initialized. 3383 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3384 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3385 Handle thread_group = create_initial_thread_group(CHECK); 3386 Universe::set_main_thread_group(thread_group()); 3387 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3388 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3389 main_thread->set_threadObj(thread_object); 3390 // Set thread status to running since main thread has 3391 // been started and running. 3392 java_lang_Thread::set_thread_status(thread_object, 3393 java_lang_Thread::RUNNABLE); 3394 3395 // The VM preresolves methods to these classes. Make sure that they get initialized 3396 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3397 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3398 call_initializeSystemClass(CHECK); 3399 3400 // get the Java runtime name after java.lang.System is initialized 3401 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3402 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3403 3404 // an instance of OutOfMemory exception has been allocated earlier 3405 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3406 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3407 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3408 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3409 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3410 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3411 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3412 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3413 } 3414 3415 void Threads::initialize_jsr292_core_classes(TRAPS) { 3416 TraceStartupTime timer("Initialize java.lang.invoke classes"); 3417 3418 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3419 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3420 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3421 } 3422 3423 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3424 extern void JDK_Version_init(); 3425 3426 // Preinitialize version info. 3427 VM_Version::early_initialize(); 3428 3429 // Check version 3430 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3431 3432 // Initialize library-based TLS 3433 ThreadLocalStorage::init(); 3434 3435 // Initialize the output stream module 3436 ostream_init(); 3437 3438 // Process java launcher properties. 3439 Arguments::process_sun_java_launcher_properties(args); 3440 3441 // Initialize the os module 3442 os::init(); 3443 3444 // Record VM creation timing statistics 3445 TraceVmCreationTime create_vm_timer; 3446 create_vm_timer.start(); 3447 3448 // Initialize system properties. 3449 Arguments::init_system_properties(); 3450 3451 // So that JDK version can be used as a discriminator when parsing arguments 3452 JDK_Version_init(); 3453 3454 // Update/Initialize System properties after JDK version number is known 3455 Arguments::init_version_specific_system_properties(); 3456 3457 // Make sure to initialize log configuration *before* parsing arguments 3458 LogConfiguration::initialize(create_vm_timer.begin_time()); 3459 3460 // Parse arguments 3461 jint parse_result = Arguments::parse(args); 3462 if (parse_result != JNI_OK) return parse_result; 3463 3464 os::init_before_ergo(); 3465 3466 jint ergo_result = Arguments::apply_ergo(); 3467 if (ergo_result != JNI_OK) return ergo_result; 3468 3469 // Final check of all ranges after ergonomics which may change values. 3470 if (!CommandLineFlagRangeList::check_ranges()) { 3471 return JNI_EINVAL; 3472 } 3473 3474 // Final check of all 'AfterErgo' constraints after ergonomics which may change values. 3475 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo); 3476 if (!constraint_result) { 3477 return JNI_EINVAL; 3478 } 3479 3480 if (PauseAtStartup) { 3481 os::pause(); 3482 } 3483 3484 HOTSPOT_VM_INIT_BEGIN(); 3485 3486 // Timing (must come after argument parsing) 3487 TraceStartupTime timer("Create VM"); 3488 3489 // Initialize the os module after parsing the args 3490 jint os_init_2_result = os::init_2(); 3491 if (os_init_2_result != JNI_OK) return os_init_2_result; 3492 3493 jint adjust_after_os_result = Arguments::adjust_after_os(); 3494 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3495 3496 // Initialize output stream logging 3497 ostream_init_log(); 3498 3499 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3500 // Must be before create_vm_init_agents() 3501 if (Arguments::init_libraries_at_startup()) { 3502 convert_vm_init_libraries_to_agents(); 3503 } 3504 3505 // Launch -agentlib/-agentpath and converted -Xrun agents 3506 if (Arguments::init_agents_at_startup()) { 3507 create_vm_init_agents(); 3508 } 3509 3510 // Initialize Threads state 3511 _thread_list = NULL; 3512 _number_of_threads = 0; 3513 _number_of_non_daemon_threads = 0; 3514 3515 // Initialize global data structures and create system classes in heap 3516 vm_init_globals(); 3517 3518 #if INCLUDE_JVMCI 3519 if (JVMCICounterSize > 0) { 3520 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 3521 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize); 3522 } else { 3523 JavaThread::_jvmci_old_thread_counters = NULL; 3524 } 3525 #endif // INCLUDE_JVMCI 3526 3527 // Attach the main thread to this os thread 3528 JavaThread* main_thread = new JavaThread(); 3529 main_thread->set_thread_state(_thread_in_vm); 3530 main_thread->initialize_thread_current(); 3531 // must do this before set_active_handles 3532 main_thread->record_stack_base_and_size(); 3533 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3534 3535 if (!main_thread->set_as_starting_thread()) { 3536 vm_shutdown_during_initialization( 3537 "Failed necessary internal allocation. Out of swap space"); 3538 delete main_thread; 3539 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3540 return JNI_ENOMEM; 3541 } 3542 3543 // Enable guard page *after* os::create_main_thread(), otherwise it would 3544 // crash Linux VM, see notes in os_linux.cpp. 3545 main_thread->create_stack_guard_pages(); 3546 3547 // Initialize Java-Level synchronization subsystem 3548 ObjectMonitor::Initialize(); 3549 3550 // Initialize global modules 3551 jint status = init_globals(); 3552 if (status != JNI_OK) { 3553 delete main_thread; 3554 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3555 return status; 3556 } 3557 3558 if (TRACE_INITIALIZE() != JNI_OK) { 3559 vm_exit_during_initialization("Failed to initialize tracing backend"); 3560 } 3561 3562 // Should be done after the heap is fully created 3563 main_thread->cache_global_variables(); 3564 3565 HandleMark hm; 3566 3567 { MutexLocker mu(Threads_lock); 3568 Threads::add(main_thread); 3569 } 3570 3571 // Any JVMTI raw monitors entered in onload will transition into 3572 // real raw monitor. VM is setup enough here for raw monitor enter. 3573 JvmtiExport::transition_pending_onload_raw_monitors(); 3574 3575 // Create the VMThread 3576 { TraceStartupTime timer("Start VMThread"); 3577 3578 VMThread::create(); 3579 Thread* vmthread = VMThread::vm_thread(); 3580 3581 if (!os::create_thread(vmthread, os::vm_thread)) { 3582 vm_exit_during_initialization("Cannot create VM thread. " 3583 "Out of system resources."); 3584 } 3585 3586 // Wait for the VM thread to become ready, and VMThread::run to initialize 3587 // Monitors can have spurious returns, must always check another state flag 3588 { 3589 MutexLocker ml(Notify_lock); 3590 os::start_thread(vmthread); 3591 while (vmthread->active_handles() == NULL) { 3592 Notify_lock->wait(); 3593 } 3594 } 3595 } 3596 3597 assert(Universe::is_fully_initialized(), "not initialized"); 3598 if (VerifyDuringStartup) { 3599 // Make sure we're starting with a clean slate. 3600 VM_Verify verify_op; 3601 VMThread::execute(&verify_op); 3602 } 3603 3604 Thread* THREAD = Thread::current(); 3605 3606 // At this point, the Universe is initialized, but we have not executed 3607 // any byte code. Now is a good time (the only time) to dump out the 3608 // internal state of the JVM for sharing. 3609 if (DumpSharedSpaces) { 3610 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3611 ShouldNotReachHere(); 3612 } 3613 3614 // Always call even when there are not JVMTI environments yet, since environments 3615 // may be attached late and JVMTI must track phases of VM execution 3616 JvmtiExport::enter_start_phase(); 3617 3618 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3619 JvmtiExport::post_vm_start(); 3620 3621 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3622 3623 // We need this for ClassDataSharing - the initial vm.info property is set 3624 // with the default value of CDS "sharing" which may be reset through 3625 // command line options. 3626 reset_vm_info_property(CHECK_JNI_ERR); 3627 3628 quicken_jni_functions(); 3629 3630 // No more stub generation allowed after that point. 3631 StubCodeDesc::freeze(); 3632 3633 // Set flag that basic initialization has completed. Used by exceptions and various 3634 // debug stuff, that does not work until all basic classes have been initialized. 3635 set_init_completed(); 3636 3637 LogConfiguration::post_initialize(); 3638 Metaspace::post_initialize(); 3639 3640 HOTSPOT_VM_INIT_END(); 3641 3642 // record VM initialization completion time 3643 #if INCLUDE_MANAGEMENT 3644 Management::record_vm_init_completed(); 3645 #endif // INCLUDE_MANAGEMENT 3646 3647 // Compute system loader. Note that this has to occur after set_init_completed, since 3648 // valid exceptions may be thrown in the process. 3649 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3650 // set_init_completed has just been called, causing exceptions not to be shortcut 3651 // anymore. We call vm_exit_during_initialization directly instead. 3652 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR)); 3653 3654 #if INCLUDE_ALL_GCS 3655 // Support for ConcurrentMarkSweep. This should be cleaned up 3656 // and better encapsulated. The ugly nested if test would go away 3657 // once things are properly refactored. XXX YSR 3658 if (UseConcMarkSweepGC || UseG1GC) { 3659 if (UseConcMarkSweepGC) { 3660 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3661 } else { 3662 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3663 } 3664 } 3665 #endif // INCLUDE_ALL_GCS 3666 3667 // Always call even when there are not JVMTI environments yet, since environments 3668 // may be attached late and JVMTI must track phases of VM execution 3669 JvmtiExport::enter_live_phase(); 3670 3671 // Signal Dispatcher needs to be started before VMInit event is posted 3672 os::signal_init(); 3673 3674 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3675 if (!DisableAttachMechanism) { 3676 AttachListener::vm_start(); 3677 if (StartAttachListener || AttachListener::init_at_startup()) { 3678 AttachListener::init(); 3679 } 3680 } 3681 3682 // Launch -Xrun agents 3683 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3684 // back-end can launch with -Xdebug -Xrunjdwp. 3685 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3686 create_vm_init_libraries(); 3687 } 3688 3689 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3690 JvmtiExport::post_vm_initialized(); 3691 3692 if (TRACE_START() != JNI_OK) { 3693 vm_exit_during_initialization("Failed to start tracing backend."); 3694 } 3695 3696 if (CleanChunkPoolAsync) { 3697 Chunk::start_chunk_pool_cleaner_task(); 3698 } 3699 3700 #if INCLUDE_JVMCI 3701 if (EnableJVMCI) { 3702 const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler"); 3703 if (jvmciCompiler != NULL) { 3704 JVMCIRuntime::save_compiler(jvmciCompiler); 3705 } 3706 } 3707 #endif // INCLUDE_JVMCI 3708 3709 // initialize compiler(s) 3710 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI 3711 CompileBroker::compilation_init(CHECK_JNI_ERR); 3712 #endif 3713 3714 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3715 // It is done after compilers are initialized, because otherwise compilations of 3716 // signature polymorphic MH intrinsics can be missed 3717 // (see SystemDictionary::find_method_handle_intrinsic). 3718 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3719 3720 #if INCLUDE_MANAGEMENT 3721 Management::initialize(THREAD); 3722 3723 if (HAS_PENDING_EXCEPTION) { 3724 // management agent fails to start possibly due to 3725 // configuration problem and is responsible for printing 3726 // stack trace if appropriate. Simply exit VM. 3727 vm_exit(1); 3728 } 3729 #endif // INCLUDE_MANAGEMENT 3730 3731 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3732 if (MemProfiling) MemProfiler::engage(); 3733 StatSampler::engage(); 3734 if (CheckJNICalls) JniPeriodicChecker::engage(); 3735 3736 BiasedLocking::init(); 3737 3738 #if INCLUDE_RTM_OPT 3739 RTMLockingCounters::init(); 3740 #endif 3741 3742 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3743 call_postVMInitHook(THREAD); 3744 // The Java side of PostVMInitHook.run must deal with all 3745 // exceptions and provide means of diagnosis. 3746 if (HAS_PENDING_EXCEPTION) { 3747 CLEAR_PENDING_EXCEPTION; 3748 } 3749 } 3750 3751 { 3752 MutexLocker ml(PeriodicTask_lock); 3753 // Make sure the WatcherThread can be started by WatcherThread::start() 3754 // or by dynamic enrollment. 3755 WatcherThread::make_startable(); 3756 // Start up the WatcherThread if there are any periodic tasks 3757 // NOTE: All PeriodicTasks should be registered by now. If they 3758 // aren't, late joiners might appear to start slowly (we might 3759 // take a while to process their first tick). 3760 if (PeriodicTask::num_tasks() > 0) { 3761 WatcherThread::start(); 3762 } 3763 } 3764 3765 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM); 3766 3767 create_vm_timer.end(); 3768 #ifdef ASSERT 3769 _vm_complete = true; 3770 #endif 3771 return JNI_OK; 3772 } 3773 3774 // type for the Agent_OnLoad and JVM_OnLoad entry points 3775 extern "C" { 3776 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3777 } 3778 // Find a command line agent library and return its entry point for 3779 // -agentlib: -agentpath: -Xrun 3780 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3781 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 3782 const char *on_load_symbols[], 3783 size_t num_symbol_entries) { 3784 OnLoadEntry_t on_load_entry = NULL; 3785 void *library = NULL; 3786 3787 if (!agent->valid()) { 3788 char buffer[JVM_MAXPATHLEN]; 3789 char ebuf[1024] = ""; 3790 const char *name = agent->name(); 3791 const char *msg = "Could not find agent library "; 3792 3793 // First check to see if agent is statically linked into executable 3794 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3795 library = agent->os_lib(); 3796 } else if (agent->is_absolute_path()) { 3797 library = os::dll_load(name, ebuf, sizeof ebuf); 3798 if (library == NULL) { 3799 const char *sub_msg = " in absolute path, with error: "; 3800 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3801 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3802 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3803 // If we can't find the agent, exit. 3804 vm_exit_during_initialization(buf, NULL); 3805 FREE_C_HEAP_ARRAY(char, buf); 3806 } 3807 } else { 3808 // Try to load the agent from the standard dll directory 3809 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3810 name)) { 3811 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3812 } 3813 if (library == NULL) { // Try the local directory 3814 char ns[1] = {0}; 3815 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3816 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3817 } 3818 if (library == NULL) { 3819 const char *sub_msg = " on the library path, with error: "; 3820 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3821 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3822 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3823 // If we can't find the agent, exit. 3824 vm_exit_during_initialization(buf, NULL); 3825 FREE_C_HEAP_ARRAY(char, buf); 3826 } 3827 } 3828 } 3829 agent->set_os_lib(library); 3830 agent->set_valid(); 3831 } 3832 3833 // Find the OnLoad function. 3834 on_load_entry = 3835 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3836 false, 3837 on_load_symbols, 3838 num_symbol_entries)); 3839 return on_load_entry; 3840 } 3841 3842 // Find the JVM_OnLoad entry point 3843 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3844 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3845 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3846 } 3847 3848 // Find the Agent_OnLoad entry point 3849 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3850 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3851 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3852 } 3853 3854 // For backwards compatibility with -Xrun 3855 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3856 // treated like -agentpath: 3857 // Must be called before agent libraries are created 3858 void Threads::convert_vm_init_libraries_to_agents() { 3859 AgentLibrary* agent; 3860 AgentLibrary* next; 3861 3862 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3863 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3864 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3865 3866 // If there is an JVM_OnLoad function it will get called later, 3867 // otherwise see if there is an Agent_OnLoad 3868 if (on_load_entry == NULL) { 3869 on_load_entry = lookup_agent_on_load(agent); 3870 if (on_load_entry != NULL) { 3871 // switch it to the agent list -- so that Agent_OnLoad will be called, 3872 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3873 Arguments::convert_library_to_agent(agent); 3874 } else { 3875 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3876 } 3877 } 3878 } 3879 } 3880 3881 // Create agents for -agentlib: -agentpath: and converted -Xrun 3882 // Invokes Agent_OnLoad 3883 // Called very early -- before JavaThreads exist 3884 void Threads::create_vm_init_agents() { 3885 extern struct JavaVM_ main_vm; 3886 AgentLibrary* agent; 3887 3888 JvmtiExport::enter_onload_phase(); 3889 3890 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3891 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3892 3893 if (on_load_entry != NULL) { 3894 // Invoke the Agent_OnLoad function 3895 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3896 if (err != JNI_OK) { 3897 vm_exit_during_initialization("agent library failed to init", agent->name()); 3898 } 3899 } else { 3900 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3901 } 3902 } 3903 JvmtiExport::enter_primordial_phase(); 3904 } 3905 3906 extern "C" { 3907 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3908 } 3909 3910 void Threads::shutdown_vm_agents() { 3911 // Send any Agent_OnUnload notifications 3912 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3913 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3914 extern struct JavaVM_ main_vm; 3915 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3916 3917 // Find the Agent_OnUnload function. 3918 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3919 os::find_agent_function(agent, 3920 false, 3921 on_unload_symbols, 3922 num_symbol_entries)); 3923 3924 // Invoke the Agent_OnUnload function 3925 if (unload_entry != NULL) { 3926 JavaThread* thread = JavaThread::current(); 3927 ThreadToNativeFromVM ttn(thread); 3928 HandleMark hm(thread); 3929 (*unload_entry)(&main_vm); 3930 } 3931 } 3932 } 3933 3934 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3935 // Invokes JVM_OnLoad 3936 void Threads::create_vm_init_libraries() { 3937 extern struct JavaVM_ main_vm; 3938 AgentLibrary* agent; 3939 3940 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3941 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3942 3943 if (on_load_entry != NULL) { 3944 // Invoke the JVM_OnLoad function 3945 JavaThread* thread = JavaThread::current(); 3946 ThreadToNativeFromVM ttn(thread); 3947 HandleMark hm(thread); 3948 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3949 if (err != JNI_OK) { 3950 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3951 } 3952 } else { 3953 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3954 } 3955 } 3956 } 3957 3958 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3959 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3960 3961 JavaThread* java_thread = NULL; 3962 // Sequential search for now. Need to do better optimization later. 3963 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3964 oop tobj = thread->threadObj(); 3965 if (!thread->is_exiting() && 3966 tobj != NULL && 3967 java_tid == java_lang_Thread::thread_id(tobj)) { 3968 java_thread = thread; 3969 break; 3970 } 3971 } 3972 return java_thread; 3973 } 3974 3975 3976 // Last thread running calls java.lang.Shutdown.shutdown() 3977 void JavaThread::invoke_shutdown_hooks() { 3978 HandleMark hm(this); 3979 3980 // We could get here with a pending exception, if so clear it now. 3981 if (this->has_pending_exception()) { 3982 this->clear_pending_exception(); 3983 } 3984 3985 EXCEPTION_MARK; 3986 Klass* k = 3987 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3988 THREAD); 3989 if (k != NULL) { 3990 // SystemDictionary::resolve_or_null will return null if there was 3991 // an exception. If we cannot load the Shutdown class, just don't 3992 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3993 // and finalizers (if runFinalizersOnExit is set) won't be run. 3994 // Note that if a shutdown hook was registered or runFinalizersOnExit 3995 // was called, the Shutdown class would have already been loaded 3996 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3997 instanceKlassHandle shutdown_klass (THREAD, k); 3998 JavaValue result(T_VOID); 3999 JavaCalls::call_static(&result, 4000 shutdown_klass, 4001 vmSymbols::shutdown_method_name(), 4002 vmSymbols::void_method_signature(), 4003 THREAD); 4004 } 4005 CLEAR_PENDING_EXCEPTION; 4006 } 4007 4008 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 4009 // the program falls off the end of main(). Another VM exit path is through 4010 // vm_exit() when the program calls System.exit() to return a value or when 4011 // there is a serious error in VM. The two shutdown paths are not exactly 4012 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 4013 // and VM_Exit op at VM level. 4014 // 4015 // Shutdown sequence: 4016 // + Shutdown native memory tracking if it is on 4017 // + Wait until we are the last non-daemon thread to execute 4018 // <-- every thing is still working at this moment --> 4019 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 4020 // shutdown hooks, run finalizers if finalization-on-exit 4021 // + Call before_exit(), prepare for VM exit 4022 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 4023 // currently the only user of this mechanism is File.deleteOnExit()) 4024 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 4025 // post thread end and vm death events to JVMTI, 4026 // stop signal thread 4027 // + Call JavaThread::exit(), it will: 4028 // > release JNI handle blocks, remove stack guard pages 4029 // > remove this thread from Threads list 4030 // <-- no more Java code from this thread after this point --> 4031 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 4032 // the compiler threads at safepoint 4033 // <-- do not use anything that could get blocked by Safepoint --> 4034 // + Disable tracing at JNI/JVM barriers 4035 // + Set _vm_exited flag for threads that are still running native code 4036 // + Delete this thread 4037 // + Call exit_globals() 4038 // > deletes tty 4039 // > deletes PerfMemory resources 4040 // + Return to caller 4041 4042 bool Threads::destroy_vm() { 4043 JavaThread* thread = JavaThread::current(); 4044 4045 #ifdef ASSERT 4046 _vm_complete = false; 4047 #endif 4048 // Wait until we are the last non-daemon thread to execute 4049 { MutexLocker nu(Threads_lock); 4050 while (Threads::number_of_non_daemon_threads() > 1) 4051 // This wait should make safepoint checks, wait without a timeout, 4052 // and wait as a suspend-equivalent condition. 4053 // 4054 // Note: If the FlatProfiler is running and this thread is waiting 4055 // for another non-daemon thread to finish, then the FlatProfiler 4056 // is waiting for the external suspend request on this thread to 4057 // complete. wait_for_ext_suspend_completion() will eventually 4058 // timeout, but that takes time. Making this wait a suspend- 4059 // equivalent condition solves that timeout problem. 4060 // 4061 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 4062 Mutex::_as_suspend_equivalent_flag); 4063 } 4064 4065 // Hang forever on exit if we are reporting an error. 4066 if (ShowMessageBoxOnError && is_error_reported()) { 4067 os::infinite_sleep(); 4068 } 4069 os::wait_for_keypress_at_exit(); 4070 4071 // run Java level shutdown hooks 4072 thread->invoke_shutdown_hooks(); 4073 4074 before_exit(thread); 4075 4076 thread->exit(true); 4077 4078 // Stop VM thread. 4079 { 4080 // 4945125 The vm thread comes to a safepoint during exit. 4081 // GC vm_operations can get caught at the safepoint, and the 4082 // heap is unparseable if they are caught. Grab the Heap_lock 4083 // to prevent this. The GC vm_operations will not be able to 4084 // queue until after the vm thread is dead. After this point, 4085 // we'll never emerge out of the safepoint before the VM exits. 4086 4087 MutexLocker ml(Heap_lock); 4088 4089 VMThread::wait_for_vm_thread_exit(); 4090 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4091 VMThread::destroy(); 4092 } 4093 4094 // clean up ideal graph printers 4095 #if defined(COMPILER2) && !defined(PRODUCT) 4096 IdealGraphPrinter::clean_up(); 4097 #endif 4098 4099 // Now, all Java threads are gone except daemon threads. Daemon threads 4100 // running Java code or in VM are stopped by the Safepoint. However, 4101 // daemon threads executing native code are still running. But they 4102 // will be stopped at native=>Java/VM barriers. Note that we can't 4103 // simply kill or suspend them, as it is inherently deadlock-prone. 4104 4105 VM_Exit::set_vm_exited(); 4106 4107 notify_vm_shutdown(); 4108 4109 delete thread; 4110 4111 #if INCLUDE_JVMCI 4112 if (JVMCICounterSize > 0) { 4113 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters); 4114 } 4115 #endif 4116 4117 // exit_globals() will delete tty 4118 exit_globals(); 4119 4120 LogConfiguration::finalize(); 4121 4122 return true; 4123 } 4124 4125 4126 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4127 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4128 return is_supported_jni_version(version); 4129 } 4130 4131 4132 jboolean Threads::is_supported_jni_version(jint version) { 4133 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4134 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4135 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4136 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4137 if (version == JNI_VERSION_9) return JNI_TRUE; 4138 return JNI_FALSE; 4139 } 4140 4141 4142 void Threads::add(JavaThread* p, bool force_daemon) { 4143 // The threads lock must be owned at this point 4144 assert_locked_or_safepoint(Threads_lock); 4145 4146 // See the comment for this method in thread.hpp for its purpose and 4147 // why it is called here. 4148 p->initialize_queues(); 4149 p->set_next(_thread_list); 4150 _thread_list = p; 4151 _number_of_threads++; 4152 oop threadObj = p->threadObj(); 4153 bool daemon = true; 4154 // Bootstrapping problem: threadObj can be null for initial 4155 // JavaThread (or for threads attached via JNI) 4156 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4157 _number_of_non_daemon_threads++; 4158 daemon = false; 4159 } 4160 4161 ThreadService::add_thread(p, daemon); 4162 4163 // Possible GC point. 4164 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p)); 4165 } 4166 4167 void Threads::remove(JavaThread* p) { 4168 // Extra scope needed for Thread_lock, so we can check 4169 // that we do not remove thread without safepoint code notice 4170 { MutexLocker ml(Threads_lock); 4171 4172 assert(includes(p), "p must be present"); 4173 4174 JavaThread* current = _thread_list; 4175 JavaThread* prev = NULL; 4176 4177 while (current != p) { 4178 prev = current; 4179 current = current->next(); 4180 } 4181 4182 if (prev) { 4183 prev->set_next(current->next()); 4184 } else { 4185 _thread_list = p->next(); 4186 } 4187 _number_of_threads--; 4188 oop threadObj = p->threadObj(); 4189 bool daemon = true; 4190 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4191 _number_of_non_daemon_threads--; 4192 daemon = false; 4193 4194 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4195 // on destroy_vm will wake up. 4196 if (number_of_non_daemon_threads() == 1) { 4197 Threads_lock->notify_all(); 4198 } 4199 } 4200 ThreadService::remove_thread(p, daemon); 4201 4202 // Make sure that safepoint code disregard this thread. This is needed since 4203 // the thread might mess around with locks after this point. This can cause it 4204 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4205 // of this thread since it is removed from the queue. 4206 p->set_terminated_value(); 4207 } // unlock Threads_lock 4208 4209 // Since Events::log uses a lock, we grab it outside the Threads_lock 4210 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p)); 4211 } 4212 4213 // Threads_lock must be held when this is called (or must be called during a safepoint) 4214 bool Threads::includes(JavaThread* p) { 4215 assert(Threads_lock->is_locked(), "sanity check"); 4216 ALL_JAVA_THREADS(q) { 4217 if (q == p) { 4218 return true; 4219 } 4220 } 4221 return false; 4222 } 4223 4224 // Operations on the Threads list for GC. These are not explicitly locked, 4225 // but the garbage collector must provide a safe context for them to run. 4226 // In particular, these things should never be called when the Threads_lock 4227 // is held by some other thread. (Note: the Safepoint abstraction also 4228 // uses the Threads_lock to guarantee this property. It also makes sure that 4229 // all threads gets blocked when exiting or starting). 4230 4231 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4232 ALL_JAVA_THREADS(p) { 4233 p->oops_do(f, cld_f, cf); 4234 } 4235 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4236 } 4237 4238 void Threads::change_thread_claim_parity() { 4239 // Set the new claim parity. 4240 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2, 4241 "Not in range."); 4242 _thread_claim_parity++; 4243 if (_thread_claim_parity == 3) _thread_claim_parity = 1; 4244 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2, 4245 "Not in range."); 4246 } 4247 4248 #ifdef ASSERT 4249 void Threads::assert_all_threads_claimed() { 4250 ALL_JAVA_THREADS(p) { 4251 const int thread_parity = p->oops_do_parity(); 4252 assert((thread_parity == _thread_claim_parity), 4253 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity); 4254 } 4255 } 4256 #endif // ASSERT 4257 4258 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4259 int cp = Threads::thread_claim_parity(); 4260 ALL_JAVA_THREADS(p) { 4261 if (p->claim_oops_do(is_par, cp)) { 4262 p->oops_do(f, cld_f, cf); 4263 } 4264 } 4265 VMThread* vmt = VMThread::vm_thread(); 4266 if (vmt->claim_oops_do(is_par, cp)) { 4267 vmt->oops_do(f, cld_f, cf); 4268 } 4269 } 4270 4271 #if INCLUDE_ALL_GCS 4272 // Used by ParallelScavenge 4273 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4274 ALL_JAVA_THREADS(p) { 4275 q->enqueue(new ThreadRootsTask(p)); 4276 } 4277 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4278 } 4279 4280 // Used by Parallel Old 4281 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4282 ALL_JAVA_THREADS(p) { 4283 q->enqueue(new ThreadRootsMarkingTask(p)); 4284 } 4285 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4286 } 4287 #endif // INCLUDE_ALL_GCS 4288 4289 void Threads::nmethods_do(CodeBlobClosure* cf) { 4290 ALL_JAVA_THREADS(p) { 4291 p->nmethods_do(cf); 4292 } 4293 VMThread::vm_thread()->nmethods_do(cf); 4294 } 4295 4296 void Threads::metadata_do(void f(Metadata*)) { 4297 ALL_JAVA_THREADS(p) { 4298 p->metadata_do(f); 4299 } 4300 } 4301 4302 class ThreadHandlesClosure : public ThreadClosure { 4303 void (*_f)(Metadata*); 4304 public: 4305 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4306 virtual void do_thread(Thread* thread) { 4307 thread->metadata_handles_do(_f); 4308 } 4309 }; 4310 4311 void Threads::metadata_handles_do(void f(Metadata*)) { 4312 // Only walk the Handles in Thread. 4313 ThreadHandlesClosure handles_closure(f); 4314 threads_do(&handles_closure); 4315 } 4316 4317 void Threads::deoptimized_wrt_marked_nmethods() { 4318 ALL_JAVA_THREADS(p) { 4319 p->deoptimized_wrt_marked_nmethods(); 4320 } 4321 } 4322 4323 4324 // Get count Java threads that are waiting to enter the specified monitor. 4325 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4326 address monitor, 4327 bool doLock) { 4328 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4329 "must grab Threads_lock or be at safepoint"); 4330 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4331 4332 int i = 0; 4333 { 4334 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4335 ALL_JAVA_THREADS(p) { 4336 if (!p->can_call_java()) continue; 4337 4338 address pending = (address)p->current_pending_monitor(); 4339 if (pending == monitor) { // found a match 4340 if (i < count) result->append(p); // save the first count matches 4341 i++; 4342 } 4343 } 4344 } 4345 return result; 4346 } 4347 4348 4349 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, 4350 bool doLock) { 4351 assert(doLock || 4352 Threads_lock->owned_by_self() || 4353 SafepointSynchronize::is_at_safepoint(), 4354 "must grab Threads_lock or be at safepoint"); 4355 4356 // NULL owner means not locked so we can skip the search 4357 if (owner == NULL) return NULL; 4358 4359 { 4360 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4361 ALL_JAVA_THREADS(p) { 4362 // first, see if owner is the address of a Java thread 4363 if (owner == (address)p) return p; 4364 } 4365 } 4366 // Cannot assert on lack of success here since this function may be 4367 // used by code that is trying to report useful problem information 4368 // like deadlock detection. 4369 if (UseHeavyMonitors) return NULL; 4370 4371 // If we didn't find a matching Java thread and we didn't force use of 4372 // heavyweight monitors, then the owner is the stack address of the 4373 // Lock Word in the owning Java thread's stack. 4374 // 4375 JavaThread* the_owner = NULL; 4376 { 4377 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4378 ALL_JAVA_THREADS(q) { 4379 if (q->is_lock_owned(owner)) { 4380 the_owner = q; 4381 break; 4382 } 4383 } 4384 } 4385 // cannot assert on lack of success here; see above comment 4386 return the_owner; 4387 } 4388 4389 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4390 void Threads::print_on(outputStream* st, bool print_stacks, 4391 bool internal_format, bool print_concurrent_locks) { 4392 char buf[32]; 4393 st->print_raw_cr(os::local_time_string(buf, sizeof(buf))); 4394 4395 st->print_cr("Full thread dump %s (%s %s):", 4396 Abstract_VM_Version::vm_name(), 4397 Abstract_VM_Version::vm_release(), 4398 Abstract_VM_Version::vm_info_string()); 4399 st->cr(); 4400 4401 #if INCLUDE_SERVICES 4402 // Dump concurrent locks 4403 ConcurrentLocksDump concurrent_locks; 4404 if (print_concurrent_locks) { 4405 concurrent_locks.dump_at_safepoint(); 4406 } 4407 #endif // INCLUDE_SERVICES 4408 4409 ALL_JAVA_THREADS(p) { 4410 ResourceMark rm; 4411 p->print_on(st); 4412 if (print_stacks) { 4413 if (internal_format) { 4414 p->trace_stack(); 4415 } else { 4416 p->print_stack_on(st); 4417 } 4418 } 4419 st->cr(); 4420 #if INCLUDE_SERVICES 4421 if (print_concurrent_locks) { 4422 concurrent_locks.print_locks_on(p, st); 4423 } 4424 #endif // INCLUDE_SERVICES 4425 } 4426 4427 VMThread::vm_thread()->print_on(st); 4428 st->cr(); 4429 Universe::heap()->print_gc_threads_on(st); 4430 WatcherThread* wt = WatcherThread::watcher_thread(); 4431 if (wt != NULL) { 4432 wt->print_on(st); 4433 st->cr(); 4434 } 4435 st->flush(); 4436 } 4437 4438 // Threads::print_on_error() is called by fatal error handler. It's possible 4439 // that VM is not at safepoint and/or current thread is inside signal handler. 4440 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4441 // memory (even in resource area), it might deadlock the error handler. 4442 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4443 int buflen) { 4444 bool found_current = false; 4445 st->print_cr("Java Threads: ( => current thread )"); 4446 ALL_JAVA_THREADS(thread) { 4447 bool is_current = (current == thread); 4448 found_current = found_current || is_current; 4449 4450 st->print("%s", is_current ? "=>" : " "); 4451 4452 st->print(PTR_FORMAT, p2i(thread)); 4453 st->print(" "); 4454 thread->print_on_error(st, buf, buflen); 4455 st->cr(); 4456 } 4457 st->cr(); 4458 4459 st->print_cr("Other Threads:"); 4460 if (VMThread::vm_thread()) { 4461 bool is_current = (current == VMThread::vm_thread()); 4462 found_current = found_current || is_current; 4463 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4464 4465 st->print(PTR_FORMAT, p2i(VMThread::vm_thread())); 4466 st->print(" "); 4467 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4468 st->cr(); 4469 } 4470 WatcherThread* wt = WatcherThread::watcher_thread(); 4471 if (wt != NULL) { 4472 bool is_current = (current == wt); 4473 found_current = found_current || is_current; 4474 st->print("%s", is_current ? "=>" : " "); 4475 4476 st->print(PTR_FORMAT, p2i(wt)); 4477 st->print(" "); 4478 wt->print_on_error(st, buf, buflen); 4479 st->cr(); 4480 } 4481 if (!found_current) { 4482 st->cr(); 4483 st->print("=>" PTR_FORMAT " (exited) ", p2i(current)); 4484 current->print_on_error(st, buf, buflen); 4485 st->cr(); 4486 } 4487 st->cr(); 4488 st->print_cr("Threads with active compile tasks:"); 4489 print_threads_compiling(st, buf, buflen); 4490 } 4491 4492 void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) { 4493 ALL_JAVA_THREADS(thread) { 4494 if (thread->is_Compiler_thread()) { 4495 CompilerThread* ct = (CompilerThread*) thread; 4496 if (ct->task() != NULL) { 4497 thread->print_name_on_error(st, buf, buflen); 4498 ct->task()->print(st, NULL, true, true); 4499 } 4500 } 4501 } 4502 } 4503 4504 4505 // Internal SpinLock and Mutex 4506 // Based on ParkEvent 4507 4508 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4509 // 4510 // We employ SpinLocks _only for low-contention, fixed-length 4511 // short-duration critical sections where we're concerned 4512 // about native mutex_t or HotSpot Mutex:: latency. 4513 // The mux construct provides a spin-then-block mutual exclusion 4514 // mechanism. 4515 // 4516 // Testing has shown that contention on the ListLock guarding gFreeList 4517 // is common. If we implement ListLock as a simple SpinLock it's common 4518 // for the JVM to devolve to yielding with little progress. This is true 4519 // despite the fact that the critical sections protected by ListLock are 4520 // extremely short. 4521 // 4522 // TODO-FIXME: ListLock should be of type SpinLock. 4523 // We should make this a 1st-class type, integrated into the lock 4524 // hierarchy as leaf-locks. Critically, the SpinLock structure 4525 // should have sufficient padding to avoid false-sharing and excessive 4526 // cache-coherency traffic. 4527 4528 4529 typedef volatile int SpinLockT; 4530 4531 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4532 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4533 return; // normal fast-path return 4534 } 4535 4536 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4537 TEVENT(SpinAcquire - ctx); 4538 int ctr = 0; 4539 int Yields = 0; 4540 for (;;) { 4541 while (*adr != 0) { 4542 ++ctr; 4543 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4544 if (Yields > 5) { 4545 os::naked_short_sleep(1); 4546 } else { 4547 os::naked_yield(); 4548 ++Yields; 4549 } 4550 } else { 4551 SpinPause(); 4552 } 4553 } 4554 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4555 } 4556 } 4557 4558 void Thread::SpinRelease(volatile int * adr) { 4559 assert(*adr != 0, "invariant"); 4560 OrderAccess::fence(); // guarantee at least release consistency. 4561 // Roach-motel semantics. 4562 // It's safe if subsequent LDs and STs float "up" into the critical section, 4563 // but prior LDs and STs within the critical section can't be allowed 4564 // to reorder or float past the ST that releases the lock. 4565 // Loads and stores in the critical section - which appear in program 4566 // order before the store that releases the lock - must also appear 4567 // before the store that releases the lock in memory visibility order. 4568 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4569 // the ST of 0 into the lock-word which releases the lock, so fence 4570 // more than covers this on all platforms. 4571 *adr = 0; 4572 } 4573 4574 // muxAcquire and muxRelease: 4575 // 4576 // * muxAcquire and muxRelease support a single-word lock-word construct. 4577 // The LSB of the word is set IFF the lock is held. 4578 // The remainder of the word points to the head of a singly-linked list 4579 // of threads blocked on the lock. 4580 // 4581 // * The current implementation of muxAcquire-muxRelease uses its own 4582 // dedicated Thread._MuxEvent instance. If we're interested in 4583 // minimizing the peak number of extant ParkEvent instances then 4584 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4585 // as certain invariants were satisfied. Specifically, care would need 4586 // to be taken with regards to consuming unpark() "permits". 4587 // A safe rule of thumb is that a thread would never call muxAcquire() 4588 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4589 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4590 // consume an unpark() permit intended for monitorenter, for instance. 4591 // One way around this would be to widen the restricted-range semaphore 4592 // implemented in park(). Another alternative would be to provide 4593 // multiple instances of the PlatformEvent() for each thread. One 4594 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4595 // 4596 // * Usage: 4597 // -- Only as leaf locks 4598 // -- for short-term locking only as muxAcquire does not perform 4599 // thread state transitions. 4600 // 4601 // Alternatives: 4602 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4603 // but with parking or spin-then-park instead of pure spinning. 4604 // * Use Taura-Oyama-Yonenzawa locks. 4605 // * It's possible to construct a 1-0 lock if we encode the lockword as 4606 // (List,LockByte). Acquire will CAS the full lockword while Release 4607 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4608 // acquiring threads use timers (ParkTimed) to detect and recover from 4609 // the stranding window. Thread/Node structures must be aligned on 256-byte 4610 // boundaries by using placement-new. 4611 // * Augment MCS with advisory back-link fields maintained with CAS(). 4612 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4613 // The validity of the backlinks must be ratified before we trust the value. 4614 // If the backlinks are invalid the exiting thread must back-track through the 4615 // the forward links, which are always trustworthy. 4616 // * Add a successor indication. The LockWord is currently encoded as 4617 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4618 // to provide the usual futile-wakeup optimization. 4619 // See RTStt for details. 4620 // * Consider schedctl.sc_nopreempt to cover the critical section. 4621 // 4622 4623 4624 typedef volatile intptr_t MutexT; // Mux Lock-word 4625 enum MuxBits { LOCKBIT = 1 }; 4626 4627 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4628 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4629 if (w == 0) return; 4630 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4631 return; 4632 } 4633 4634 TEVENT(muxAcquire - Contention); 4635 ParkEvent * const Self = Thread::current()->_MuxEvent; 4636 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4637 for (;;) { 4638 int its = (os::is_MP() ? 100 : 0) + 1; 4639 4640 // Optional spin phase: spin-then-park strategy 4641 while (--its >= 0) { 4642 w = *Lock; 4643 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4644 return; 4645 } 4646 } 4647 4648 Self->reset(); 4649 Self->OnList = intptr_t(Lock); 4650 // The following fence() isn't _strictly necessary as the subsequent 4651 // CAS() both serializes execution and ratifies the fetched *Lock value. 4652 OrderAccess::fence(); 4653 for (;;) { 4654 w = *Lock; 4655 if ((w & LOCKBIT) == 0) { 4656 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4657 Self->OnList = 0; // hygiene - allows stronger asserts 4658 return; 4659 } 4660 continue; // Interference -- *Lock changed -- Just retry 4661 } 4662 assert(w & LOCKBIT, "invariant"); 4663 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4664 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4665 } 4666 4667 while (Self->OnList != 0) { 4668 Self->park(); 4669 } 4670 } 4671 } 4672 4673 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4674 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4675 if (w == 0) return; 4676 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4677 return; 4678 } 4679 4680 TEVENT(muxAcquire - Contention); 4681 ParkEvent * ReleaseAfter = NULL; 4682 if (ev == NULL) { 4683 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4684 } 4685 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4686 for (;;) { 4687 guarantee(ev->OnList == 0, "invariant"); 4688 int its = (os::is_MP() ? 100 : 0) + 1; 4689 4690 // Optional spin phase: spin-then-park strategy 4691 while (--its >= 0) { 4692 w = *Lock; 4693 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4694 if (ReleaseAfter != NULL) { 4695 ParkEvent::Release(ReleaseAfter); 4696 } 4697 return; 4698 } 4699 } 4700 4701 ev->reset(); 4702 ev->OnList = intptr_t(Lock); 4703 // The following fence() isn't _strictly necessary as the subsequent 4704 // CAS() both serializes execution and ratifies the fetched *Lock value. 4705 OrderAccess::fence(); 4706 for (;;) { 4707 w = *Lock; 4708 if ((w & LOCKBIT) == 0) { 4709 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4710 ev->OnList = 0; 4711 // We call ::Release while holding the outer lock, thus 4712 // artificially lengthening the critical section. 4713 // Consider deferring the ::Release() until the subsequent unlock(), 4714 // after we've dropped the outer lock. 4715 if (ReleaseAfter != NULL) { 4716 ParkEvent::Release(ReleaseAfter); 4717 } 4718 return; 4719 } 4720 continue; // Interference -- *Lock changed -- Just retry 4721 } 4722 assert(w & LOCKBIT, "invariant"); 4723 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4724 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4725 } 4726 4727 while (ev->OnList != 0) { 4728 ev->park(); 4729 } 4730 } 4731 } 4732 4733 // Release() must extract a successor from the list and then wake that thread. 4734 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4735 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4736 // Release() would : 4737 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4738 // (B) Extract a successor from the private list "in-hand" 4739 // (C) attempt to CAS() the residual back into *Lock over null. 4740 // If there were any newly arrived threads and the CAS() would fail. 4741 // In that case Release() would detach the RATs, re-merge the list in-hand 4742 // with the RATs and repeat as needed. Alternately, Release() might 4743 // detach and extract a successor, but then pass the residual list to the wakee. 4744 // The wakee would be responsible for reattaching and remerging before it 4745 // competed for the lock. 4746 // 4747 // Both "pop" and DMR are immune from ABA corruption -- there can be 4748 // multiple concurrent pushers, but only one popper or detacher. 4749 // This implementation pops from the head of the list. This is unfair, 4750 // but tends to provide excellent throughput as hot threads remain hot. 4751 // (We wake recently run threads first). 4752 // 4753 // All paths through muxRelease() will execute a CAS. 4754 // Release consistency -- We depend on the CAS in muxRelease() to provide full 4755 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4756 // executed within the critical section are complete and globally visible before the 4757 // store (CAS) to the lock-word that releases the lock becomes globally visible. 4758 void Thread::muxRelease(volatile intptr_t * Lock) { 4759 for (;;) { 4760 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4761 assert(w & LOCKBIT, "invariant"); 4762 if (w == LOCKBIT) return; 4763 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4764 assert(List != NULL, "invariant"); 4765 assert(List->OnList == intptr_t(Lock), "invariant"); 4766 ParkEvent * const nxt = List->ListNext; 4767 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4768 4769 // The following CAS() releases the lock and pops the head element. 4770 // The CAS() also ratifies the previously fetched lock-word value. 4771 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4772 continue; 4773 } 4774 List->OnList = 0; 4775 OrderAccess::fence(); 4776 List->unpark(); 4777 return; 4778 } 4779 } 4780 4781 4782 void Threads::verify() { 4783 ALL_JAVA_THREADS(p) { 4784 p->verify(); 4785 } 4786 VMThread* thread = VMThread::vm_thread(); 4787 if (thread != NULL) thread->verify(); 4788 }