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