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