1 /* 2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/classLoader.hpp" 27 #include "classfile/javaClasses.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/scopeDesc.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "interpreter/interpreter.hpp" 33 #include "interpreter/linkResolver.hpp" 34 #include "interpreter/oopMapCache.hpp" 35 #include "jvmtifiles/jvmtiEnv.hpp" 36 #include "memory/gcLocker.inline.hpp" 37 #include "memory/metaspaceShared.hpp" 38 #include "memory/oopFactory.hpp" 39 #include "memory/universe.inline.hpp" 40 #include "oops/instanceKlass.hpp" 41 #include "oops/objArrayOop.hpp" 42 #include "oops/oop.inline.hpp" 43 #include "oops/symbol.hpp" 44 #include "prims/jvm_misc.hpp" 45 #include "prims/jvmtiExport.hpp" 46 #include "prims/jvmtiThreadState.hpp" 47 #include "prims/privilegedStack.hpp" 48 #include "runtime/arguments.hpp" 49 #include "runtime/biasedLocking.hpp" 50 #include "runtime/deoptimization.hpp" 51 #include "runtime/fprofiler.hpp" 52 #include "runtime/frame.inline.hpp" 53 #include "runtime/init.hpp" 54 #include "runtime/interfaceSupport.hpp" 55 #include "runtime/java.hpp" 56 #include "runtime/javaCalls.hpp" 57 #include "runtime/jniPeriodicChecker.hpp" 58 #include "runtime/memprofiler.hpp" 59 #include "runtime/mutexLocker.hpp" 60 #include "runtime/objectMonitor.hpp" 61 #include "runtime/orderAccess.inline.hpp" 62 #include "runtime/osThread.hpp" 63 #include "runtime/safepoint.hpp" 64 #include "runtime/sharedRuntime.hpp" 65 #include "runtime/statSampler.hpp" 66 #include "runtime/stubRoutines.hpp" 67 #include "runtime/task.hpp" 68 #include "runtime/thread.inline.hpp" 69 #include "runtime/threadCritical.hpp" 70 #include "runtime/threadLocalStorage.hpp" 71 #include "runtime/vframe.hpp" 72 #include "runtime/vframeArray.hpp" 73 #include "runtime/vframe_hp.hpp" 74 #include "runtime/vmThread.hpp" 75 #include "runtime/vm_operations.hpp" 76 #include "services/attachListener.hpp" 77 #include "services/management.hpp" 78 #include "services/memTracker.hpp" 79 #include "services/threadService.hpp" 80 #include "trace/tracing.hpp" 81 #include "trace/traceMacros.hpp" 82 #include "utilities/defaultStream.hpp" 83 #include "utilities/dtrace.hpp" 84 #include "utilities/events.hpp" 85 #include "utilities/preserveException.hpp" 86 #include "utilities/macros.hpp" 87 #ifdef TARGET_OS_FAMILY_linux 88 # include "os_linux.inline.hpp" 89 #endif 90 #ifdef TARGET_OS_FAMILY_solaris 91 # include "os_solaris.inline.hpp" 92 #endif 93 #ifdef TARGET_OS_FAMILY_windows 94 # include "os_windows.inline.hpp" 95 #endif 96 #ifdef TARGET_OS_FAMILY_bsd 97 # include "os_bsd.inline.hpp" 98 #endif 99 #if INCLUDE_ALL_GCS 100 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 101 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 102 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 103 #endif // INCLUDE_ALL_GCS 104 #ifdef COMPILER1 105 #include "c1/c1_Compiler.hpp" 106 #endif 107 #ifdef COMPILER2 108 #include "opto/c2compiler.hpp" 109 #include "opto/idealGraphPrinter.hpp" 110 #endif 111 #if INCLUDE_RTM_OPT 112 #include "runtime/rtmLocking.hpp" 113 #endif 114 115 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 116 117 #ifdef DTRACE_ENABLED 118 119 // Only bother with this argument setup if dtrace is available 120 121 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 122 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 123 124 #define DTRACE_THREAD_PROBE(probe, javathread) \ 125 { \ 126 ResourceMark rm(this); \ 127 int len = 0; \ 128 const char* name = (javathread)->get_thread_name(); \ 129 len = strlen(name); \ 130 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 131 (char *) name, len, \ 132 java_lang_Thread::thread_id((javathread)->threadObj()), \ 133 (uintptr_t) (javathread)->osthread()->thread_id(), \ 134 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 135 } 136 137 #else // ndef DTRACE_ENABLED 138 139 #define DTRACE_THREAD_PROBE(probe, javathread) 140 141 #endif // ndef DTRACE_ENABLED 142 143 144 // Class hierarchy 145 // - Thread 146 // - VMThread 147 // - WatcherThread 148 // - ConcurrentMarkSweepThread 149 // - JavaThread 150 // - CompilerThread 151 152 // ======= Thread ======== 153 // Support for forcing alignment of thread objects for biased locking 154 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 155 if (UseBiasedLocking) { 156 const int alignment = markOopDesc::biased_lock_alignment; 157 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 158 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 159 : AllocateHeap(aligned_size, flags, CURRENT_PC, 160 AllocFailStrategy::RETURN_NULL); 161 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 162 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 163 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 164 "JavaThread alignment code overflowed allocated storage"); 165 if (TraceBiasedLocking) { 166 if (aligned_addr != real_malloc_addr) 167 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 168 real_malloc_addr, aligned_addr); 169 } 170 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 171 return aligned_addr; 172 } else { 173 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 174 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 175 } 176 } 177 178 void Thread::operator delete(void* p) { 179 if (UseBiasedLocking) { 180 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 181 FreeHeap(real_malloc_addr, mtThread); 182 } else { 183 FreeHeap(p, mtThread); 184 } 185 } 186 187 188 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 189 // JavaThread 190 191 192 Thread::Thread() { 193 // stack and get_thread 194 set_stack_base(NULL); 195 set_stack_size(0); 196 set_self_raw_id(0); 197 set_lgrp_id(-1); 198 199 // allocated data structures 200 set_osthread(NULL); 201 set_resource_area(new (mtThread)ResourceArea()); 202 DEBUG_ONLY(_current_resource_mark = NULL;) 203 set_handle_area(new (mtThread) HandleArea(NULL)); 204 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 205 set_active_handles(NULL); 206 set_free_handle_block(NULL); 207 set_last_handle_mark(NULL); 208 209 // This initial value ==> never claimed. 210 _oops_do_parity = 0; 211 212 // the handle mark links itself to last_handle_mark 213 new HandleMark(this); 214 215 // plain initialization 216 debug_only(_owned_locks = NULL;) 217 debug_only(_allow_allocation_count = 0;) 218 NOT_PRODUCT(_allow_safepoint_count = 0;) 219 NOT_PRODUCT(_skip_gcalot = false;) 220 _jvmti_env_iteration_count = 0; 221 set_allocated_bytes(0); 222 _vm_operation_started_count = 0; 223 _vm_operation_completed_count = 0; 224 _current_pending_monitor = NULL; 225 _current_pending_monitor_is_from_java = true; 226 _current_waiting_monitor = NULL; 227 _num_nested_signal = 0; 228 omFreeList = NULL ; 229 omFreeCount = 0 ; 230 omFreeProvision = 32 ; 231 omInUseList = NULL ; 232 omInUseCount = 0 ; 233 234 #ifdef ASSERT 235 _visited_for_critical_count = false; 236 #endif 237 238 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 239 _suspend_flags = 0; 240 241 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 242 _hashStateX = os::random() ; 243 _hashStateY = 842502087 ; 244 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 245 _hashStateW = 273326509 ; 246 247 _OnTrap = 0 ; 248 _schedctl = NULL ; 249 _Stalled = 0 ; 250 _TypeTag = 0x2BAD ; 251 252 // Many of the following fields are effectively final - immutable 253 // Note that nascent threads can't use the Native Monitor-Mutex 254 // construct until the _MutexEvent is initialized ... 255 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 256 // we might instead use a stack of ParkEvents that we could provision on-demand. 257 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 258 // and ::Release() 259 _ParkEvent = ParkEvent::Allocate (this) ; 260 _SleepEvent = ParkEvent::Allocate (this) ; 261 _MutexEvent = ParkEvent::Allocate (this) ; 262 _MuxEvent = ParkEvent::Allocate (this) ; 263 264 #ifdef CHECK_UNHANDLED_OOPS 265 if (CheckUnhandledOops) { 266 _unhandled_oops = new UnhandledOops(this); 267 } 268 #endif // CHECK_UNHANDLED_OOPS 269 #ifdef ASSERT 270 if (UseBiasedLocking) { 271 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 272 assert(this == _real_malloc_address || 273 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 274 "bug in forced alignment of thread objects"); 275 } 276 #endif /* ASSERT */ 277 } 278 279 void Thread::initialize_thread_local_storage() { 280 // Note: Make sure this method only calls 281 // non-blocking operations. Otherwise, it might not work 282 // with the thread-startup/safepoint interaction. 283 284 // During Java thread startup, safepoint code should allow this 285 // method to complete because it may need to allocate memory to 286 // store information for the new thread. 287 288 // initialize structure dependent on thread local storage 289 ThreadLocalStorage::set_thread(this); 290 } 291 292 void Thread::record_stack_base_and_size() { 293 set_stack_base(os::current_stack_base()); 294 set_stack_size(os::current_stack_size()); 295 if (is_Java_thread()) { 296 ((JavaThread*) this)->set_stack_overflow_limit(); 297 } 298 // CR 7190089: on Solaris, primordial thread's stack is adjusted 299 // in initialize_thread(). Without the adjustment, stack size is 300 // incorrect if stack is set to unlimited (ulimit -s unlimited). 301 // So far, only Solaris has real implementation of initialize_thread(). 302 // 303 // set up any platform-specific state. 304 os::initialize_thread(this); 305 306 #if INCLUDE_NMT 307 // record thread's native stack, stack grows downward 308 address stack_low_addr = stack_base() - stack_size(); 309 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 310 CURRENT_PC); 311 #endif // INCLUDE_NMT 312 } 313 314 315 Thread::~Thread() { 316 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 317 ObjectSynchronizer::omFlush (this) ; 318 319 EVENT_THREAD_DESTRUCT(this); 320 321 // stack_base can be NULL if the thread is never started or exited before 322 // record_stack_base_and_size called. Although, we would like to ensure 323 // that all started threads do call record_stack_base_and_size(), there is 324 // not proper way to enforce that. 325 #if INCLUDE_NMT 326 if (_stack_base != NULL) { 327 address low_stack_addr = stack_base() - stack_size(); 328 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); 329 #ifdef ASSERT 330 set_stack_base(NULL); 331 #endif 332 } 333 #endif // INCLUDE_NMT 334 335 // deallocate data structures 336 delete resource_area(); 337 // since the handle marks are using the handle area, we have to deallocated the root 338 // handle mark before deallocating the thread's handle area, 339 assert(last_handle_mark() != NULL, "check we have an element"); 340 delete last_handle_mark(); 341 assert(last_handle_mark() == NULL, "check we have reached the end"); 342 343 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 344 // We NULL out the fields for good hygiene. 345 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 346 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 347 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 348 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 349 350 delete handle_area(); 351 delete metadata_handles(); 352 353 // osthread() can be NULL, if creation of thread failed. 354 if (osthread() != NULL) os::free_thread(osthread()); 355 356 delete _SR_lock; 357 358 // clear thread local storage if the Thread is deleting itself 359 if (this == Thread::current()) { 360 ThreadLocalStorage::set_thread(NULL); 361 } else { 362 // In the case where we're not the current thread, invalidate all the 363 // caches in case some code tries to get the current thread or the 364 // thread that was destroyed, and gets stale information. 365 ThreadLocalStorage::invalidate_all(); 366 } 367 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 368 } 369 370 // NOTE: dummy function for assertion purpose. 371 void Thread::run() { 372 ShouldNotReachHere(); 373 } 374 375 #ifdef ASSERT 376 // Private method to check for dangling thread pointer 377 void check_for_dangling_thread_pointer(Thread *thread) { 378 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 379 "possibility of dangling Thread pointer"); 380 } 381 #endif 382 383 384 #ifndef PRODUCT 385 // Tracing method for basic thread operations 386 void Thread::trace(const char* msg, const Thread* const thread) { 387 if (!TraceThreadEvents) return; 388 ResourceMark rm; 389 ThreadCritical tc; 390 const char *name = "non-Java thread"; 391 int prio = -1; 392 if (thread->is_Java_thread() 393 && !thread->is_Compiler_thread()) { 394 // The Threads_lock must be held to get information about 395 // this thread but may not be in some situations when 396 // tracing thread events. 397 bool release_Threads_lock = false; 398 if (!Threads_lock->owned_by_self()) { 399 Threads_lock->lock(); 400 release_Threads_lock = true; 401 } 402 JavaThread* jt = (JavaThread *)thread; 403 name = (char *)jt->get_thread_name(); 404 oop thread_oop = jt->threadObj(); 405 if (thread_oop != NULL) { 406 prio = java_lang_Thread::priority(thread_oop); 407 } 408 if (release_Threads_lock) { 409 Threads_lock->unlock(); 410 } 411 } 412 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 413 } 414 #endif 415 416 417 ThreadPriority Thread::get_priority(const Thread* const thread) { 418 trace("get priority", thread); 419 ThreadPriority priority; 420 // Can return an error! 421 (void)os::get_priority(thread, priority); 422 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 423 return priority; 424 } 425 426 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 427 trace("set priority", thread); 428 debug_only(check_for_dangling_thread_pointer(thread);) 429 // Can return an error! 430 (void)os::set_priority(thread, priority); 431 } 432 433 434 void Thread::start(Thread* thread) { 435 trace("start", thread); 436 // Start is different from resume in that its safety is guaranteed by context or 437 // being called from a Java method synchronized on the Thread object. 438 if (!DisableStartThread) { 439 if (thread->is_Java_thread()) { 440 // Initialize the thread state to RUNNABLE before starting this thread. 441 // Can not set it after the thread started because we do not know the 442 // exact thread state at that time. It could be in MONITOR_WAIT or 443 // in SLEEPING or some other state. 444 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 445 java_lang_Thread::RUNNABLE); 446 } 447 os::start_thread(thread); 448 } 449 } 450 451 // Enqueue a VM_Operation to do the job for us - sometime later 452 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 453 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 454 VMThread::execute(vm_stop); 455 } 456 457 458 // 459 // Check if an external suspend request has completed (or has been 460 // cancelled). Returns true if the thread is externally suspended and 461 // false otherwise. 462 // 463 // The bits parameter returns information about the code path through 464 // the routine. Useful for debugging: 465 // 466 // set in is_ext_suspend_completed(): 467 // 0x00000001 - routine was entered 468 // 0x00000010 - routine return false at end 469 // 0x00000100 - thread exited (return false) 470 // 0x00000200 - suspend request cancelled (return false) 471 // 0x00000400 - thread suspended (return true) 472 // 0x00001000 - thread is in a suspend equivalent state (return true) 473 // 0x00002000 - thread is native and walkable (return true) 474 // 0x00004000 - thread is native_trans and walkable (needed retry) 475 // 476 // set in wait_for_ext_suspend_completion(): 477 // 0x00010000 - routine was entered 478 // 0x00020000 - suspend request cancelled before loop (return false) 479 // 0x00040000 - thread suspended before loop (return true) 480 // 0x00080000 - suspend request cancelled in loop (return false) 481 // 0x00100000 - thread suspended in loop (return true) 482 // 0x00200000 - suspend not completed during retry loop (return false) 483 // 484 485 // Helper class for tracing suspend wait debug bits. 486 // 487 // 0x00000100 indicates that the target thread exited before it could 488 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 489 // 0x00080000 each indicate a cancelled suspend request so they don't 490 // count as wait failures either. 491 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 492 493 class TraceSuspendDebugBits : public StackObj { 494 private: 495 JavaThread * jt; 496 bool is_wait; 497 bool called_by_wait; // meaningful when !is_wait 498 uint32_t * bits; 499 500 public: 501 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 502 uint32_t *_bits) { 503 jt = _jt; 504 is_wait = _is_wait; 505 called_by_wait = _called_by_wait; 506 bits = _bits; 507 } 508 509 ~TraceSuspendDebugBits() { 510 if (!is_wait) { 511 #if 1 512 // By default, don't trace bits for is_ext_suspend_completed() calls. 513 // That trace is very chatty. 514 return; 515 #else 516 if (!called_by_wait) { 517 // If tracing for is_ext_suspend_completed() is enabled, then only 518 // trace calls to it from wait_for_ext_suspend_completion() 519 return; 520 } 521 #endif 522 } 523 524 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 525 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 526 MutexLocker ml(Threads_lock); // needed for get_thread_name() 527 ResourceMark rm; 528 529 tty->print_cr( 530 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 531 jt->get_thread_name(), *bits); 532 533 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 534 } 535 } 536 } 537 }; 538 #undef DEBUG_FALSE_BITS 539 540 541 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 542 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 543 544 bool did_trans_retry = false; // only do thread_in_native_trans retry once 545 bool do_trans_retry; // flag to force the retry 546 547 *bits |= 0x00000001; 548 549 do { 550 do_trans_retry = false; 551 552 if (is_exiting()) { 553 // Thread is in the process of exiting. This is always checked 554 // first to reduce the risk of dereferencing a freed JavaThread. 555 *bits |= 0x00000100; 556 return false; 557 } 558 559 if (!is_external_suspend()) { 560 // Suspend request is cancelled. This is always checked before 561 // is_ext_suspended() to reduce the risk of a rogue resume 562 // confusing the thread that made the suspend request. 563 *bits |= 0x00000200; 564 return false; 565 } 566 567 if (is_ext_suspended()) { 568 // thread is suspended 569 *bits |= 0x00000400; 570 return true; 571 } 572 573 // Now that we no longer do hard suspends of threads running 574 // native code, the target thread can be changing thread state 575 // while we are in this routine: 576 // 577 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 578 // 579 // We save a copy of the thread state as observed at this moment 580 // and make our decision about suspend completeness based on the 581 // copy. This closes the race where the thread state is seen as 582 // _thread_in_native_trans in the if-thread_blocked check, but is 583 // seen as _thread_blocked in if-thread_in_native_trans check. 584 JavaThreadState save_state = thread_state(); 585 586 if (save_state == _thread_blocked && is_suspend_equivalent()) { 587 // If the thread's state is _thread_blocked and this blocking 588 // condition is known to be equivalent to a suspend, then we can 589 // consider the thread to be externally suspended. This means that 590 // the code that sets _thread_blocked has been modified to do 591 // self-suspension if the blocking condition releases. We also 592 // used to check for CONDVAR_WAIT here, but that is now covered by 593 // the _thread_blocked with self-suspension check. 594 // 595 // Return true since we wouldn't be here unless there was still an 596 // external suspend request. 597 *bits |= 0x00001000; 598 return true; 599 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 600 // Threads running native code will self-suspend on native==>VM/Java 601 // transitions. If its stack is walkable (should always be the case 602 // unless this function is called before the actual java_suspend() 603 // call), then the wait is done. 604 *bits |= 0x00002000; 605 return true; 606 } else if (!called_by_wait && !did_trans_retry && 607 save_state == _thread_in_native_trans && 608 frame_anchor()->walkable()) { 609 // The thread is transitioning from thread_in_native to another 610 // thread state. check_safepoint_and_suspend_for_native_trans() 611 // will force the thread to self-suspend. If it hasn't gotten 612 // there yet we may have caught the thread in-between the native 613 // code check above and the self-suspend. Lucky us. If we were 614 // called by wait_for_ext_suspend_completion(), then it 615 // will be doing the retries so we don't have to. 616 // 617 // Since we use the saved thread state in the if-statement above, 618 // there is a chance that the thread has already transitioned to 619 // _thread_blocked by the time we get here. In that case, we will 620 // make a single unnecessary pass through the logic below. This 621 // doesn't hurt anything since we still do the trans retry. 622 623 *bits |= 0x00004000; 624 625 // Once the thread leaves thread_in_native_trans for another 626 // thread state, we break out of this retry loop. We shouldn't 627 // need this flag to prevent us from getting back here, but 628 // sometimes paranoia is good. 629 did_trans_retry = true; 630 631 // We wait for the thread to transition to a more usable state. 632 for (int i = 1; i <= SuspendRetryCount; i++) { 633 // We used to do an "os::yield_all(i)" call here with the intention 634 // that yielding would increase on each retry. However, the parameter 635 // is ignored on Linux which means the yield didn't scale up. Waiting 636 // on the SR_lock below provides a much more predictable scale up for 637 // the delay. It also provides a simple/direct point to check for any 638 // safepoint requests from the VMThread 639 640 // temporarily drops SR_lock while doing wait with safepoint check 641 // (if we're a JavaThread - the WatcherThread can also call this) 642 // and increase delay with each retry 643 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 644 645 // check the actual thread state instead of what we saved above 646 if (thread_state() != _thread_in_native_trans) { 647 // the thread has transitioned to another thread state so 648 // try all the checks (except this one) one more time. 649 do_trans_retry = true; 650 break; 651 } 652 } // end retry loop 653 654 655 } 656 } while (do_trans_retry); 657 658 *bits |= 0x00000010; 659 return false; 660 } 661 662 // 663 // Wait for an external suspend request to complete (or be cancelled). 664 // Returns true if the thread is externally suspended and false otherwise. 665 // 666 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 667 uint32_t *bits) { 668 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 669 false /* !called_by_wait */, bits); 670 671 // local flag copies to minimize SR_lock hold time 672 bool is_suspended; 673 bool pending; 674 uint32_t reset_bits; 675 676 // set a marker so is_ext_suspend_completed() knows we are the caller 677 *bits |= 0x00010000; 678 679 // We use reset_bits to reinitialize the bits value at the top of 680 // each retry loop. This allows the caller to make use of any 681 // unused bits for their own marking purposes. 682 reset_bits = *bits; 683 684 { 685 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 686 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 687 delay, bits); 688 pending = is_external_suspend(); 689 } 690 // must release SR_lock to allow suspension to complete 691 692 if (!pending) { 693 // A cancelled suspend request is the only false return from 694 // is_ext_suspend_completed() that keeps us from entering the 695 // retry loop. 696 *bits |= 0x00020000; 697 return false; 698 } 699 700 if (is_suspended) { 701 *bits |= 0x00040000; 702 return true; 703 } 704 705 for (int i = 1; i <= retries; i++) { 706 *bits = reset_bits; // reinit to only track last retry 707 708 // We used to do an "os::yield_all(i)" call here with the intention 709 // that yielding would increase on each retry. However, the parameter 710 // is ignored on Linux which means the yield didn't scale up. Waiting 711 // on the SR_lock below provides a much more predictable scale up for 712 // the delay. It also provides a simple/direct point to check for any 713 // safepoint requests from the VMThread 714 715 { 716 MutexLocker ml(SR_lock()); 717 // wait with safepoint check (if we're a JavaThread - the WatcherThread 718 // can also call this) and increase delay with each retry 719 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 720 721 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 722 delay, bits); 723 724 // It is possible for the external suspend request to be cancelled 725 // (by a resume) before the actual suspend operation is completed. 726 // Refresh our local copy to see if we still need to wait. 727 pending = is_external_suspend(); 728 } 729 730 if (!pending) { 731 // A cancelled suspend request is the only false return from 732 // is_ext_suspend_completed() that keeps us from staying in the 733 // retry loop. 734 *bits |= 0x00080000; 735 return false; 736 } 737 738 if (is_suspended) { 739 *bits |= 0x00100000; 740 return true; 741 } 742 } // end retry loop 743 744 // thread did not suspend after all our retries 745 *bits |= 0x00200000; 746 return false; 747 } 748 749 #ifndef PRODUCT 750 void JavaThread::record_jump(address target, address instr, const char* file, int line) { 751 752 // This should not need to be atomic as the only way for simultaneous 753 // updates is via interrupts. Even then this should be rare or non-existent 754 // and we don't care that much anyway. 755 756 int index = _jmp_ring_index; 757 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 758 _jmp_ring[index]._target = (intptr_t) target; 759 _jmp_ring[index]._instruction = (intptr_t) instr; 760 _jmp_ring[index]._file = file; 761 _jmp_ring[index]._line = line; 762 } 763 #endif /* PRODUCT */ 764 765 // Called by flat profiler 766 // Callers have already called wait_for_ext_suspend_completion 767 // The assertion for that is currently too complex to put here: 768 bool JavaThread::profile_last_Java_frame(frame* _fr) { 769 bool gotframe = false; 770 // self suspension saves needed state. 771 if (has_last_Java_frame() && _anchor.walkable()) { 772 *_fr = pd_last_frame(); 773 gotframe = true; 774 } 775 return gotframe; 776 } 777 778 void Thread::interrupt(Thread* thread) { 779 trace("interrupt", thread); 780 debug_only(check_for_dangling_thread_pointer(thread);) 781 os::interrupt(thread); 782 } 783 784 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 785 trace("is_interrupted", thread); 786 debug_only(check_for_dangling_thread_pointer(thread);) 787 // Note: If clear_interrupted==false, this simply fetches and 788 // returns the value of the field osthread()->interrupted(). 789 return os::is_interrupted(thread, clear_interrupted); 790 } 791 792 793 // GC Support 794 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 795 jint thread_parity = _oops_do_parity; 796 if (thread_parity != strong_roots_parity) { 797 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 798 if (res == thread_parity) { 799 return true; 800 } else { 801 guarantee(res == strong_roots_parity, "Or else what?"); 802 assert(SharedHeap::heap()->workers()->active_workers() > 0, 803 "Should only fail when parallel."); 804 return false; 805 } 806 } 807 assert(SharedHeap::heap()->workers()->active_workers() > 0, 808 "Should only fail when parallel."); 809 return false; 810 } 811 812 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 813 active_handles()->oops_do(f); 814 // Do oop for ThreadShadow 815 f->do_oop((oop*)&_pending_exception); 816 handle_area()->oops_do(f); 817 } 818 819 void Thread::nmethods_do(CodeBlobClosure* cf) { 820 // no nmethods in a generic thread... 821 } 822 823 void Thread::metadata_do(void f(Metadata*)) { 824 if (metadata_handles() != NULL) { 825 for (int i = 0; i< metadata_handles()->length(); i++) { 826 f(metadata_handles()->at(i)); 827 } 828 } 829 } 830 831 void Thread::print_on(outputStream* st) const { 832 // get_priority assumes osthread initialized 833 if (osthread() != NULL) { 834 int os_prio; 835 if (os::get_native_priority(this, &os_prio) == OS_OK) { 836 st->print("os_prio=%d ", os_prio); 837 } 838 st->print("tid=" INTPTR_FORMAT " ", this); 839 osthread()->print_on(st); 840 } 841 debug_only(if (WizardMode) print_owned_locks_on(st);) 842 } 843 844 // Thread::print_on_error() is called by fatal error handler. Don't use 845 // any lock or allocate memory. 846 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 847 if (is_VM_thread()) st->print("VMThread"); 848 else if (is_Compiler_thread()) st->print("CompilerThread"); 849 else if (is_Java_thread()) st->print("JavaThread"); 850 else if (is_GC_task_thread()) st->print("GCTaskThread"); 851 else if (is_Watcher_thread()) st->print("WatcherThread"); 852 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 853 else st->print("Thread"); 854 855 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 856 _stack_base - _stack_size, _stack_base); 857 858 if (osthread()) { 859 st->print(" [id=%d]", osthread()->thread_id()); 860 } 861 } 862 863 #ifdef ASSERT 864 void Thread::print_owned_locks_on(outputStream* st) const { 865 Monitor *cur = _owned_locks; 866 if (cur == NULL) { 867 st->print(" (no locks) "); 868 } else { 869 st->print_cr(" Locks owned:"); 870 while(cur) { 871 cur->print_on(st); 872 cur = cur->next(); 873 } 874 } 875 } 876 877 static int ref_use_count = 0; 878 879 bool Thread::owns_locks_but_compiled_lock() const { 880 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 881 if (cur != Compile_lock) return true; 882 } 883 return false; 884 } 885 886 887 #endif 888 889 #ifndef PRODUCT 890 891 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 892 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 893 // no threads which allow_vm_block's are held 894 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 895 // Check if current thread is allowed to block at a safepoint 896 if (!(_allow_safepoint_count == 0)) 897 fatal("Possible safepoint reached by thread that does not allow it"); 898 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 899 fatal("LEAF method calling lock?"); 900 } 901 902 #ifdef ASSERT 903 if (potential_vm_operation && is_Java_thread() 904 && !Universe::is_bootstrapping()) { 905 // Make sure we do not hold any locks that the VM thread also uses. 906 // This could potentially lead to deadlocks 907 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 908 // Threads_lock is special, since the safepoint synchronization will not start before this is 909 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 910 // since it is used to transfer control between JavaThreads and the VMThread 911 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 912 if ( (cur->allow_vm_block() && 913 cur != Threads_lock && 914 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 915 cur != VMOperationRequest_lock && 916 cur != VMOperationQueue_lock) || 917 cur->rank() == Mutex::special) { 918 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name())); 919 } 920 } 921 } 922 923 if (GCALotAtAllSafepoints) { 924 // We could enter a safepoint here and thus have a gc 925 InterfaceSupport::check_gc_alot(); 926 } 927 #endif 928 } 929 #endif 930 931 bool Thread::is_in_stack(address adr) const { 932 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 933 address end = os::current_stack_pointer(); 934 // Allow non Java threads to call this without stack_base 935 if (_stack_base == NULL) return true; 936 if (stack_base() >= adr && adr >= end) return true; 937 938 return false; 939 } 940 941 942 bool Thread::is_in_usable_stack(address adr) const { 943 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 944 size_t usable_stack_size = _stack_size - stack_guard_size; 945 946 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 947 } 948 949 950 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 951 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 952 // used for compilation in the future. If that change is made, the need for these methods 953 // should be revisited, and they should be removed if possible. 954 955 bool Thread::is_lock_owned(address adr) const { 956 return on_local_stack(adr); 957 } 958 959 bool Thread::set_as_starting_thread() { 960 // NOTE: this must be called inside the main thread. 961 return os::create_main_thread((JavaThread*)this); 962 } 963 964 static void initialize_class(Symbol* class_name, TRAPS) { 965 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 966 InstanceKlass::cast(klass)->initialize(CHECK); 967 } 968 969 970 // Creates the initial ThreadGroup 971 static Handle create_initial_thread_group(TRAPS) { 972 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 973 instanceKlassHandle klass (THREAD, k); 974 975 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 976 { 977 JavaValue result(T_VOID); 978 JavaCalls::call_special(&result, 979 system_instance, 980 klass, 981 vmSymbols::object_initializer_name(), 982 vmSymbols::void_method_signature(), 983 CHECK_NH); 984 } 985 Universe::set_system_thread_group(system_instance()); 986 987 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 988 { 989 JavaValue result(T_VOID); 990 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 991 JavaCalls::call_special(&result, 992 main_instance, 993 klass, 994 vmSymbols::object_initializer_name(), 995 vmSymbols::threadgroup_string_void_signature(), 996 system_instance, 997 string, 998 CHECK_NH); 999 } 1000 return main_instance; 1001 } 1002 1003 // Creates the initial Thread 1004 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1005 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1006 instanceKlassHandle klass (THREAD, k); 1007 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1008 1009 java_lang_Thread::set_thread(thread_oop(), thread); 1010 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1011 thread->set_threadObj(thread_oop()); 1012 1013 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1014 1015 JavaValue result(T_VOID); 1016 JavaCalls::call_special(&result, thread_oop, 1017 klass, 1018 vmSymbols::object_initializer_name(), 1019 vmSymbols::threadgroup_string_void_signature(), 1020 thread_group, 1021 string, 1022 CHECK_NULL); 1023 return thread_oop(); 1024 } 1025 1026 static void call_initializeSystemClass(TRAPS) { 1027 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1028 instanceKlassHandle klass (THREAD, k); 1029 1030 JavaValue result(T_VOID); 1031 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1032 vmSymbols::void_method_signature(), CHECK); 1033 } 1034 1035 char java_runtime_name[128] = ""; 1036 char java_runtime_version[128] = ""; 1037 1038 // extract the JRE name from sun.misc.Version.java_runtime_name 1039 static const char* get_java_runtime_name(TRAPS) { 1040 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1041 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1042 fieldDescriptor fd; 1043 bool found = k != NULL && 1044 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1045 vmSymbols::string_signature(), &fd); 1046 if (found) { 1047 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1048 if (name_oop == NULL) 1049 return NULL; 1050 const char* name = java_lang_String::as_utf8_string(name_oop, 1051 java_runtime_name, 1052 sizeof(java_runtime_name)); 1053 return name; 1054 } else { 1055 return NULL; 1056 } 1057 } 1058 1059 // extract the JRE version from sun.misc.Version.java_runtime_version 1060 static const char* get_java_runtime_version(TRAPS) { 1061 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1062 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1063 fieldDescriptor fd; 1064 bool found = k != NULL && 1065 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1066 vmSymbols::string_signature(), &fd); 1067 if (found) { 1068 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1069 if (name_oop == NULL) 1070 return NULL; 1071 const char* name = java_lang_String::as_utf8_string(name_oop, 1072 java_runtime_version, 1073 sizeof(java_runtime_version)); 1074 return name; 1075 } else { 1076 return NULL; 1077 } 1078 } 1079 1080 // General purpose hook into Java code, run once when the VM is initialized. 1081 // The Java library method itself may be changed independently from the VM. 1082 static void call_postVMInitHook(TRAPS) { 1083 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1084 instanceKlassHandle klass (THREAD, k); 1085 if (klass.not_null()) { 1086 JavaValue result(T_VOID); 1087 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1088 vmSymbols::void_method_signature(), 1089 CHECK); 1090 } 1091 } 1092 1093 static void reset_vm_info_property(TRAPS) { 1094 // the vm info string 1095 ResourceMark rm(THREAD); 1096 const char *vm_info = VM_Version::vm_info_string(); 1097 1098 // java.lang.System class 1099 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1100 instanceKlassHandle klass (THREAD, k); 1101 1102 // setProperty arguments 1103 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1104 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1105 1106 // return value 1107 JavaValue r(T_OBJECT); 1108 1109 // public static String setProperty(String key, String value); 1110 JavaCalls::call_static(&r, 1111 klass, 1112 vmSymbols::setProperty_name(), 1113 vmSymbols::string_string_string_signature(), 1114 key_str, 1115 value_str, 1116 CHECK); 1117 } 1118 1119 1120 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1121 assert(thread_group.not_null(), "thread group should be specified"); 1122 assert(threadObj() == NULL, "should only create Java thread object once"); 1123 1124 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1125 instanceKlassHandle klass (THREAD, k); 1126 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1127 1128 java_lang_Thread::set_thread(thread_oop(), this); 1129 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1130 set_threadObj(thread_oop()); 1131 1132 JavaValue result(T_VOID); 1133 if (thread_name != NULL) { 1134 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1135 // Thread gets assigned specified name and null target 1136 JavaCalls::call_special(&result, 1137 thread_oop, 1138 klass, 1139 vmSymbols::object_initializer_name(), 1140 vmSymbols::threadgroup_string_void_signature(), 1141 thread_group, // Argument 1 1142 name, // Argument 2 1143 THREAD); 1144 } else { 1145 // Thread gets assigned name "Thread-nnn" and null target 1146 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1147 JavaCalls::call_special(&result, 1148 thread_oop, 1149 klass, 1150 vmSymbols::object_initializer_name(), 1151 vmSymbols::threadgroup_runnable_void_signature(), 1152 thread_group, // Argument 1 1153 Handle(), // Argument 2 1154 THREAD); 1155 } 1156 1157 1158 if (daemon) { 1159 java_lang_Thread::set_daemon(thread_oop()); 1160 } 1161 1162 if (HAS_PENDING_EXCEPTION) { 1163 return; 1164 } 1165 1166 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1167 Handle threadObj(this, this->threadObj()); 1168 1169 JavaCalls::call_special(&result, 1170 thread_group, 1171 group, 1172 vmSymbols::add_method_name(), 1173 vmSymbols::thread_void_signature(), 1174 threadObj, // Arg 1 1175 THREAD); 1176 1177 1178 } 1179 1180 // NamedThread -- non-JavaThread subclasses with multiple 1181 // uniquely named instances should derive from this. 1182 NamedThread::NamedThread() : Thread() { 1183 _name = NULL; 1184 _processed_thread = NULL; 1185 } 1186 1187 NamedThread::~NamedThread() { 1188 if (_name != NULL) { 1189 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1190 _name = NULL; 1191 } 1192 } 1193 1194 void NamedThread::set_name(const char* format, ...) { 1195 guarantee(_name == NULL, "Only get to set name once."); 1196 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1197 guarantee(_name != NULL, "alloc failure"); 1198 va_list ap; 1199 va_start(ap, format); 1200 jio_vsnprintf(_name, max_name_len, format, ap); 1201 va_end(ap); 1202 } 1203 1204 void NamedThread::print_on(outputStream* st) const { 1205 st->print("\"%s\" ", name()); 1206 Thread::print_on(st); 1207 st->cr(); 1208 } 1209 1210 1211 // ======= WatcherThread ======== 1212 1213 // The watcher thread exists to simulate timer interrupts. It should 1214 // be replaced by an abstraction over whatever native support for 1215 // timer interrupts exists on the platform. 1216 1217 WatcherThread* WatcherThread::_watcher_thread = NULL; 1218 bool WatcherThread::_startable = false; 1219 volatile bool WatcherThread::_should_terminate = false; 1220 1221 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1222 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1223 if (os::create_thread(this, os::watcher_thread)) { 1224 _watcher_thread = this; 1225 1226 // Set the watcher thread to the highest OS priority which should not be 1227 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1228 // is created. The only normal thread using this priority is the reference 1229 // handler thread, which runs for very short intervals only. 1230 // If the VMThread's priority is not lower than the WatcherThread profiling 1231 // will be inaccurate. 1232 os::set_priority(this, MaxPriority); 1233 if (!DisableStartThread) { 1234 os::start_thread(this); 1235 } 1236 } 1237 } 1238 1239 int WatcherThread::sleep() const { 1240 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1241 1242 // remaining will be zero if there are no tasks, 1243 // causing the WatcherThread to sleep until a task is 1244 // enrolled 1245 int remaining = PeriodicTask::time_to_wait(); 1246 int time_slept = 0; 1247 1248 // we expect this to timeout - we only ever get unparked when 1249 // we should terminate or when a new task has been enrolled 1250 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1251 1252 jlong time_before_loop = os::javaTimeNanos(); 1253 1254 for (;;) { 1255 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1256 jlong now = os::javaTimeNanos(); 1257 1258 if (remaining == 0) { 1259 // if we didn't have any tasks we could have waited for a long time 1260 // consider the time_slept zero and reset time_before_loop 1261 time_slept = 0; 1262 time_before_loop = now; 1263 } else { 1264 // need to recalculate since we might have new tasks in _tasks 1265 time_slept = (int) ((now - time_before_loop) / 1000000); 1266 } 1267 1268 // Change to task list or spurious wakeup of some kind 1269 if (timedout || _should_terminate) { 1270 break; 1271 } 1272 1273 remaining = PeriodicTask::time_to_wait(); 1274 if (remaining == 0) { 1275 // Last task was just disenrolled so loop around and wait until 1276 // another task gets enrolled 1277 continue; 1278 } 1279 1280 remaining -= time_slept; 1281 if (remaining <= 0) 1282 break; 1283 } 1284 1285 return time_slept; 1286 } 1287 1288 void WatcherThread::run() { 1289 assert(this == watcher_thread(), "just checking"); 1290 1291 this->record_stack_base_and_size(); 1292 this->initialize_thread_local_storage(); 1293 this->set_active_handles(JNIHandleBlock::allocate_block()); 1294 while(!_should_terminate) { 1295 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1296 assert(watcher_thread() == this, "thread consistency check"); 1297 1298 // Calculate how long it'll be until the next PeriodicTask work 1299 // should be done, and sleep that amount of time. 1300 int time_waited = sleep(); 1301 1302 if (is_error_reported()) { 1303 // A fatal error has happened, the error handler(VMError::report_and_die) 1304 // should abort JVM after creating an error log file. However in some 1305 // rare cases, the error handler itself might deadlock. Here we try to 1306 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1307 // 1308 // This code is in WatcherThread because WatcherThread wakes up 1309 // periodically so the fatal error handler doesn't need to do anything; 1310 // also because the WatcherThread is less likely to crash than other 1311 // threads. 1312 1313 for (;;) { 1314 if (!ShowMessageBoxOnError 1315 && (OnError == NULL || OnError[0] == '\0') 1316 && Arguments::abort_hook() == NULL) { 1317 os::sleep(this, 2 * 60 * 1000, false); 1318 fdStream err(defaultStream::output_fd()); 1319 err.print_raw_cr("# [ timer expired, abort... ]"); 1320 // skip atexit/vm_exit/vm_abort hooks 1321 os::die(); 1322 } 1323 1324 // Wake up 5 seconds later, the fatal handler may reset OnError or 1325 // ShowMessageBoxOnError when it is ready to abort. 1326 os::sleep(this, 5 * 1000, false); 1327 } 1328 } 1329 1330 PeriodicTask::real_time_tick(time_waited); 1331 } 1332 1333 // Signal that it is terminated 1334 { 1335 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1336 _watcher_thread = NULL; 1337 Terminator_lock->notify(); 1338 } 1339 1340 // Thread destructor usually does this.. 1341 ThreadLocalStorage::set_thread(NULL); 1342 } 1343 1344 void WatcherThread::start() { 1345 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1346 1347 if (watcher_thread() == NULL && _startable) { 1348 _should_terminate = false; 1349 // Create the single instance of WatcherThread 1350 new WatcherThread(); 1351 } 1352 } 1353 1354 void WatcherThread::make_startable() { 1355 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1356 _startable = true; 1357 } 1358 1359 void WatcherThread::stop() { 1360 { 1361 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1362 _should_terminate = true; 1363 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1364 1365 WatcherThread* watcher = watcher_thread(); 1366 if (watcher != NULL) 1367 watcher->unpark(); 1368 } 1369 1370 // it is ok to take late safepoints here, if needed 1371 MutexLocker mu(Terminator_lock); 1372 1373 while(watcher_thread() != NULL) { 1374 // This wait should make safepoint checks, wait without a timeout, 1375 // and wait as a suspend-equivalent condition. 1376 // 1377 // Note: If the FlatProfiler is running, then this thread is waiting 1378 // for the WatcherThread to terminate and the WatcherThread, via the 1379 // FlatProfiler task, is waiting for the external suspend request on 1380 // this thread to complete. wait_for_ext_suspend_completion() will 1381 // eventually timeout, but that takes time. Making this wait a 1382 // suspend-equivalent condition solves that timeout problem. 1383 // 1384 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1385 Mutex::_as_suspend_equivalent_flag); 1386 } 1387 } 1388 1389 void WatcherThread::unpark() { 1390 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1391 PeriodicTask_lock->notify(); 1392 } 1393 1394 void WatcherThread::print_on(outputStream* st) const { 1395 st->print("\"%s\" ", name()); 1396 Thread::print_on(st); 1397 st->cr(); 1398 } 1399 1400 // ======= JavaThread ======== 1401 1402 // A JavaThread is a normal Java thread 1403 1404 void JavaThread::initialize() { 1405 // Initialize fields 1406 1407 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1408 set_claimed_par_id(UINT_MAX); 1409 1410 set_saved_exception_pc(NULL); 1411 set_threadObj(NULL); 1412 _anchor.clear(); 1413 set_entry_point(NULL); 1414 set_jni_functions(jni_functions()); 1415 set_callee_target(NULL); 1416 set_vm_result(NULL); 1417 set_vm_result_2(NULL); 1418 set_vframe_array_head(NULL); 1419 set_vframe_array_last(NULL); 1420 set_deferred_locals(NULL); 1421 set_deopt_mark(NULL); 1422 set_deopt_nmethod(NULL); 1423 clear_must_deopt_id(); 1424 set_monitor_chunks(NULL); 1425 set_next(NULL); 1426 set_thread_state(_thread_new); 1427 #if INCLUDE_NMT 1428 set_recorder(NULL); 1429 #endif 1430 _terminated = _not_terminated; 1431 _privileged_stack_top = NULL; 1432 _array_for_gc = NULL; 1433 _suspend_equivalent = false; 1434 _in_deopt_handler = 0; 1435 _doing_unsafe_access = false; 1436 _stack_guard_state = stack_guard_unused; 1437 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1438 _exception_pc = 0; 1439 _exception_handler_pc = 0; 1440 _is_method_handle_return = 0; 1441 _jvmti_thread_state= NULL; 1442 _should_post_on_exceptions_flag = JNI_FALSE; 1443 _jvmti_get_loaded_classes_closure = NULL; 1444 _interp_only_mode = 0; 1445 _special_runtime_exit_condition = _no_async_condition; 1446 _pending_async_exception = NULL; 1447 _thread_stat = NULL; 1448 _thread_stat = new ThreadStatistics(); 1449 _blocked_on_compilation = false; 1450 _jni_active_critical = 0; 1451 _do_not_unlock_if_synchronized = false; 1452 _cached_monitor_info = NULL; 1453 _parker = Parker::Allocate(this) ; 1454 1455 #ifndef PRODUCT 1456 _jmp_ring_index = 0; 1457 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1458 record_jump(NULL, NULL, NULL, 0); 1459 } 1460 #endif /* PRODUCT */ 1461 1462 set_thread_profiler(NULL); 1463 if (FlatProfiler::is_active()) { 1464 // This is where we would decide to either give each thread it's own profiler 1465 // or use one global one from FlatProfiler, 1466 // or up to some count of the number of profiled threads, etc. 1467 ThreadProfiler* pp = new ThreadProfiler(); 1468 pp->engage(); 1469 set_thread_profiler(pp); 1470 } 1471 1472 // Setup safepoint state info for this thread 1473 ThreadSafepointState::create(this); 1474 1475 debug_only(_java_call_counter = 0); 1476 1477 // JVMTI PopFrame support 1478 _popframe_condition = popframe_inactive; 1479 _popframe_preserved_args = NULL; 1480 _popframe_preserved_args_size = 0; 1481 1482 pd_initialize(); 1483 } 1484 1485 #if INCLUDE_ALL_GCS 1486 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1487 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1488 #endif // INCLUDE_ALL_GCS 1489 1490 JavaThread::JavaThread(bool is_attaching_via_jni) : 1491 Thread() 1492 #if INCLUDE_ALL_GCS 1493 , _satb_mark_queue(&_satb_mark_queue_set), 1494 _dirty_card_queue(&_dirty_card_queue_set) 1495 #endif // INCLUDE_ALL_GCS 1496 { 1497 initialize(); 1498 if (is_attaching_via_jni) { 1499 _jni_attach_state = _attaching_via_jni; 1500 } else { 1501 _jni_attach_state = _not_attaching_via_jni; 1502 } 1503 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1504 _safepoint_visible = false; 1505 } 1506 1507 bool JavaThread::reguard_stack(address cur_sp) { 1508 if (_stack_guard_state != stack_guard_yellow_disabled) { 1509 return true; // Stack already guarded or guard pages not needed. 1510 } 1511 1512 if (register_stack_overflow()) { 1513 // For those architectures which have separate register and 1514 // memory stacks, we must check the register stack to see if 1515 // it has overflowed. 1516 return false; 1517 } 1518 1519 // Java code never executes within the yellow zone: the latter is only 1520 // there to provoke an exception during stack banging. If java code 1521 // is executing there, either StackShadowPages should be larger, or 1522 // some exception code in c1, c2 or the interpreter isn't unwinding 1523 // when it should. 1524 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1525 1526 enable_stack_yellow_zone(); 1527 return true; 1528 } 1529 1530 bool JavaThread::reguard_stack(void) { 1531 return reguard_stack(os::current_stack_pointer()); 1532 } 1533 1534 1535 void JavaThread::block_if_vm_exited() { 1536 if (_terminated == _vm_exited) { 1537 // _vm_exited is set at safepoint, and Threads_lock is never released 1538 // we will block here forever 1539 Threads_lock->lock_without_safepoint_check(); 1540 ShouldNotReachHere(); 1541 } 1542 } 1543 1544 1545 // Remove this ifdef when C1 is ported to the compiler interface. 1546 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1547 1548 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1549 Thread() 1550 #if INCLUDE_ALL_GCS 1551 , _satb_mark_queue(&_satb_mark_queue_set), 1552 _dirty_card_queue(&_dirty_card_queue_set) 1553 #endif // INCLUDE_ALL_GCS 1554 { 1555 if (TraceThreadEvents) { 1556 tty->print_cr("creating thread %p", this); 1557 } 1558 initialize(); 1559 _jni_attach_state = _not_attaching_via_jni; 1560 set_entry_point(entry_point); 1561 // Create the native thread itself. 1562 // %note runtime_23 1563 os::ThreadType thr_type = os::java_thread; 1564 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1565 os::java_thread; 1566 os::create_thread(this, thr_type, stack_sz); 1567 _safepoint_visible = false; 1568 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1569 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1570 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1571 // the exception consists of creating the exception object & initializing it, initialization 1572 // will leave the VM via a JavaCall and then all locks must be unlocked). 1573 // 1574 // The thread is still suspended when we reach here. Thread must be explicit started 1575 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1576 // by calling Threads:add. The reason why this is not done here, is because the thread 1577 // object must be fully initialized (take a look at JVM_Start) 1578 } 1579 1580 JavaThread::~JavaThread() { 1581 if (TraceThreadEvents) { 1582 tty->print_cr("terminate thread %p", this); 1583 } 1584 1585 // By now, this thread should already be invisible to safepoint, 1586 // and its per-thread recorder also collected. 1587 assert(!is_safepoint_visible(), "wrong state"); 1588 #if INCLUDE_NMT 1589 assert(get_recorder() == NULL, "Already collected"); 1590 #endif // INCLUDE_NMT 1591 1592 // JSR166 -- return the parker to the free list 1593 Parker::Release(_parker); 1594 _parker = NULL ; 1595 1596 // Free any remaining previous UnrollBlock 1597 vframeArray* old_array = vframe_array_last(); 1598 1599 if (old_array != NULL) { 1600 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1601 old_array->set_unroll_block(NULL); 1602 delete old_info; 1603 delete old_array; 1604 } 1605 1606 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1607 if (deferred != NULL) { 1608 // This can only happen if thread is destroyed before deoptimization occurs. 1609 assert(deferred->length() != 0, "empty array!"); 1610 do { 1611 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1612 deferred->remove_at(0); 1613 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1614 delete dlv; 1615 } while (deferred->length() != 0); 1616 delete deferred; 1617 } 1618 1619 // All Java related clean up happens in exit 1620 ThreadSafepointState::destroy(this); 1621 if (_thread_profiler != NULL) delete _thread_profiler; 1622 if (_thread_stat != NULL) delete _thread_stat; 1623 } 1624 1625 1626 // The first routine called by a new Java thread 1627 void JavaThread::run() { 1628 // initialize thread-local alloc buffer related fields 1629 this->initialize_tlab(); 1630 1631 // used to test validity of stack trace backs 1632 this->record_base_of_stack_pointer(); 1633 1634 // Record real stack base and size. 1635 this->record_stack_base_and_size(); 1636 1637 // Initialize thread local storage; set before calling MutexLocker 1638 this->initialize_thread_local_storage(); 1639 1640 this->create_stack_guard_pages(); 1641 1642 this->cache_global_variables(); 1643 1644 // Thread is now sufficient initialized to be handled by the safepoint code as being 1645 // in the VM. Change thread state from _thread_new to _thread_in_vm 1646 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1647 1648 assert(JavaThread::current() == this, "sanity check"); 1649 assert(!Thread::current()->owns_locks(), "sanity check"); 1650 1651 DTRACE_THREAD_PROBE(start, this); 1652 1653 // This operation might block. We call that after all safepoint checks for a new thread has 1654 // been completed. 1655 this->set_active_handles(JNIHandleBlock::allocate_block()); 1656 1657 if (JvmtiExport::should_post_thread_life()) { 1658 JvmtiExport::post_thread_start(this); 1659 } 1660 1661 EventThreadStart event; 1662 if (event.should_commit()) { 1663 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1664 event.commit(); 1665 } 1666 1667 // We call another function to do the rest so we are sure that the stack addresses used 1668 // from there will be lower than the stack base just computed 1669 thread_main_inner(); 1670 1671 // Note, thread is no longer valid at this point! 1672 } 1673 1674 1675 void JavaThread::thread_main_inner() { 1676 assert(JavaThread::current() == this, "sanity check"); 1677 assert(this->threadObj() != NULL, "just checking"); 1678 1679 // Execute thread entry point unless this thread has a pending exception 1680 // or has been stopped before starting. 1681 // Note: Due to JVM_StopThread we can have pending exceptions already! 1682 if (!this->has_pending_exception() && 1683 !java_lang_Thread::is_stillborn(this->threadObj())) { 1684 { 1685 ResourceMark rm(this); 1686 this->set_native_thread_name(this->get_thread_name()); 1687 } 1688 HandleMark hm(this); 1689 this->entry_point()(this, this); 1690 } 1691 1692 DTRACE_THREAD_PROBE(stop, this); 1693 1694 this->exit(false); 1695 delete this; 1696 } 1697 1698 1699 static void ensure_join(JavaThread* thread) { 1700 // We do not need to grap the Threads_lock, since we are operating on ourself. 1701 Handle threadObj(thread, thread->threadObj()); 1702 assert(threadObj.not_null(), "java thread object must exist"); 1703 ObjectLocker lock(threadObj, thread); 1704 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1705 thread->clear_pending_exception(); 1706 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1707 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1708 // Clear the native thread instance - this makes isAlive return false and allows the join() 1709 // to complete once we've done the notify_all below 1710 java_lang_Thread::set_thread(threadObj(), NULL); 1711 lock.notify_all(thread); 1712 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1713 thread->clear_pending_exception(); 1714 } 1715 1716 1717 // For any new cleanup additions, please check to see if they need to be applied to 1718 // cleanup_failed_attach_current_thread as well. 1719 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1720 assert(this == JavaThread::current(), "thread consistency check"); 1721 1722 HandleMark hm(this); 1723 Handle uncaught_exception(this, this->pending_exception()); 1724 this->clear_pending_exception(); 1725 Handle threadObj(this, this->threadObj()); 1726 assert(threadObj.not_null(), "Java thread object should be created"); 1727 1728 if (get_thread_profiler() != NULL) { 1729 get_thread_profiler()->disengage(); 1730 ResourceMark rm; 1731 get_thread_profiler()->print(get_thread_name()); 1732 } 1733 1734 1735 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1736 { 1737 EXCEPTION_MARK; 1738 1739 CLEAR_PENDING_EXCEPTION; 1740 } 1741 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1742 // has to be fixed by a runtime query method 1743 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1744 // JSR-166: change call from from ThreadGroup.uncaughtException to 1745 // java.lang.Thread.dispatchUncaughtException 1746 if (uncaught_exception.not_null()) { 1747 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1748 { 1749 EXCEPTION_MARK; 1750 // Check if the method Thread.dispatchUncaughtException() exists. If so 1751 // call it. Otherwise we have an older library without the JSR-166 changes, 1752 // so call ThreadGroup.uncaughtException() 1753 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1754 CallInfo callinfo; 1755 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1756 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1757 vmSymbols::dispatchUncaughtException_name(), 1758 vmSymbols::throwable_void_signature(), 1759 KlassHandle(), false, false, THREAD); 1760 CLEAR_PENDING_EXCEPTION; 1761 methodHandle method = callinfo.selected_method(); 1762 if (method.not_null()) { 1763 JavaValue result(T_VOID); 1764 JavaCalls::call_virtual(&result, 1765 threadObj, thread_klass, 1766 vmSymbols::dispatchUncaughtException_name(), 1767 vmSymbols::throwable_void_signature(), 1768 uncaught_exception, 1769 THREAD); 1770 } else { 1771 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1772 JavaValue result(T_VOID); 1773 JavaCalls::call_virtual(&result, 1774 group, thread_group, 1775 vmSymbols::uncaughtException_name(), 1776 vmSymbols::thread_throwable_void_signature(), 1777 threadObj, // Arg 1 1778 uncaught_exception, // Arg 2 1779 THREAD); 1780 } 1781 if (HAS_PENDING_EXCEPTION) { 1782 ResourceMark rm(this); 1783 jio_fprintf(defaultStream::error_stream(), 1784 "\nException: %s thrown from the UncaughtExceptionHandler" 1785 " in thread \"%s\"\n", 1786 pending_exception()->klass()->external_name(), 1787 get_thread_name()); 1788 CLEAR_PENDING_EXCEPTION; 1789 } 1790 } 1791 } 1792 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. A detach operation must only 1865 // get here if there are no Java frames on the stack. Therefore, any 1866 // owned monitors at this point MUST be JNI-acquired monitors which are 1867 // pre-inflated and in the monitor cache. 1868 // 1869 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1870 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1871 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1872 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1873 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1874 } 1875 1876 // These things needs to be done while we are still a Java Thread. Make sure that thread 1877 // is in a consistent state, in case GC happens 1878 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1879 1880 if (active_handles() != NULL) { 1881 JNIHandleBlock* block = active_handles(); 1882 set_active_handles(NULL); 1883 JNIHandleBlock::release_block(block); 1884 } 1885 1886 if (free_handle_block() != NULL) { 1887 JNIHandleBlock* block = free_handle_block(); 1888 set_free_handle_block(NULL); 1889 JNIHandleBlock::release_block(block); 1890 } 1891 1892 // These have to be removed while this is still a valid thread. 1893 remove_stack_guard_pages(); 1894 1895 if (UseTLAB) { 1896 tlab().make_parsable(true); // retire TLAB 1897 } 1898 1899 if (JvmtiEnv::environments_might_exist()) { 1900 JvmtiExport::cleanup_thread(this); 1901 } 1902 1903 // We must flush any deferred card marks before removing a thread from 1904 // the list of active threads. 1905 Universe::heap()->flush_deferred_store_barrier(this); 1906 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1907 1908 #if INCLUDE_ALL_GCS 1909 // We must flush the G1-related buffers before removing a thread 1910 // from the list of active threads. We must do this after any deferred 1911 // card marks have been flushed (above) so that any entries that are 1912 // added to the thread's dirty card queue as a result are not lost. 1913 if (UseG1GC) { 1914 flush_barrier_queues(); 1915 } 1916 #endif // INCLUDE_ALL_GCS 1917 1918 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1919 Threads::remove(this); 1920 } 1921 1922 #if INCLUDE_ALL_GCS 1923 // Flush G1-related queues. 1924 void JavaThread::flush_barrier_queues() { 1925 satb_mark_queue().flush(); 1926 dirty_card_queue().flush(); 1927 } 1928 1929 void JavaThread::initialize_queues() { 1930 assert(!SafepointSynchronize::is_at_safepoint(), 1931 "we should not be at a safepoint"); 1932 1933 ObjPtrQueue& satb_queue = satb_mark_queue(); 1934 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1935 // The SATB queue should have been constructed with its active 1936 // field set to false. 1937 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1938 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1939 // If we are creating the thread during a marking cycle, we should 1940 // set the active field of the SATB queue to true. 1941 if (satb_queue_set.is_active()) { 1942 satb_queue.set_active(true); 1943 } 1944 1945 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1946 // The dirty card queue should have been constructed with its 1947 // active field set to true. 1948 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1949 } 1950 #endif // INCLUDE_ALL_GCS 1951 1952 void JavaThread::cleanup_failed_attach_current_thread() { 1953 if (get_thread_profiler() != NULL) { 1954 get_thread_profiler()->disengage(); 1955 ResourceMark rm; 1956 get_thread_profiler()->print(get_thread_name()); 1957 } 1958 1959 if (active_handles() != NULL) { 1960 JNIHandleBlock* block = active_handles(); 1961 set_active_handles(NULL); 1962 JNIHandleBlock::release_block(block); 1963 } 1964 1965 if (free_handle_block() != NULL) { 1966 JNIHandleBlock* block = free_handle_block(); 1967 set_free_handle_block(NULL); 1968 JNIHandleBlock::release_block(block); 1969 } 1970 1971 // These have to be removed while this is still a valid thread. 1972 remove_stack_guard_pages(); 1973 1974 if (UseTLAB) { 1975 tlab().make_parsable(true); // retire TLAB, if any 1976 } 1977 1978 #if INCLUDE_ALL_GCS 1979 if (UseG1GC) { 1980 flush_barrier_queues(); 1981 } 1982 #endif // INCLUDE_ALL_GCS 1983 1984 Threads::remove(this); 1985 delete this; 1986 } 1987 1988 1989 1990 1991 JavaThread* JavaThread::active() { 1992 Thread* thread = ThreadLocalStorage::thread(); 1993 assert(thread != NULL, "just checking"); 1994 if (thread->is_Java_thread()) { 1995 return (JavaThread*) thread; 1996 } else { 1997 assert(thread->is_VM_thread(), "this must be a vm thread"); 1998 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1999 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2000 assert(ret->is_Java_thread(), "must be a Java thread"); 2001 return ret; 2002 } 2003 } 2004 2005 bool JavaThread::is_lock_owned(address adr) const { 2006 if (Thread::is_lock_owned(adr)) return true; 2007 2008 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2009 if (chunk->contains(adr)) return true; 2010 } 2011 2012 return false; 2013 } 2014 2015 2016 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2017 chunk->set_next(monitor_chunks()); 2018 set_monitor_chunks(chunk); 2019 } 2020 2021 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2022 guarantee(monitor_chunks() != NULL, "must be non empty"); 2023 if (monitor_chunks() == chunk) { 2024 set_monitor_chunks(chunk->next()); 2025 } else { 2026 MonitorChunk* prev = monitor_chunks(); 2027 while (prev->next() != chunk) prev = prev->next(); 2028 prev->set_next(chunk->next()); 2029 } 2030 } 2031 2032 // JVM support. 2033 2034 // Note: this function shouldn't block if it's called in 2035 // _thread_in_native_trans state (such as from 2036 // check_special_condition_for_native_trans()). 2037 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2038 2039 if (has_last_Java_frame() && has_async_condition()) { 2040 // If we are at a polling page safepoint (not a poll return) 2041 // then we must defer async exception because live registers 2042 // will be clobbered by the exception path. Poll return is 2043 // ok because the call we a returning from already collides 2044 // with exception handling registers and so there is no issue. 2045 // (The exception handling path kills call result registers but 2046 // this is ok since the exception kills the result anyway). 2047 2048 if (is_at_poll_safepoint()) { 2049 // if the code we are returning to has deoptimized we must defer 2050 // the exception otherwise live registers get clobbered on the 2051 // exception path before deoptimization is able to retrieve them. 2052 // 2053 RegisterMap map(this, false); 2054 frame caller_fr = last_frame().sender(&map); 2055 assert(caller_fr.is_compiled_frame(), "what?"); 2056 if (caller_fr.is_deoptimized_frame()) { 2057 if (TraceExceptions) { 2058 ResourceMark rm; 2059 tty->print_cr("deferred async exception at compiled safepoint"); 2060 } 2061 return; 2062 } 2063 } 2064 } 2065 2066 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2067 if (condition == _no_async_condition) { 2068 // Conditions have changed since has_special_runtime_exit_condition() 2069 // was called: 2070 // - if we were here only because of an external suspend request, 2071 // then that was taken care of above (or cancelled) so we are done 2072 // - if we were here because of another async request, then it has 2073 // been cleared between the has_special_runtime_exit_condition() 2074 // and now so again we are done 2075 return; 2076 } 2077 2078 // Check for pending async. exception 2079 if (_pending_async_exception != NULL) { 2080 // Only overwrite an already pending exception, if it is not a threadDeath. 2081 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2082 2083 // We cannot call Exceptions::_throw(...) here because we cannot block 2084 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2085 2086 if (TraceExceptions) { 2087 ResourceMark rm; 2088 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2089 if (has_last_Java_frame() ) { 2090 frame f = last_frame(); 2091 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2092 } 2093 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2094 } 2095 _pending_async_exception = NULL; 2096 clear_has_async_exception(); 2097 } 2098 } 2099 2100 if (check_unsafe_error && 2101 condition == _async_unsafe_access_error && !has_pending_exception()) { 2102 condition = _no_async_condition; // done 2103 switch (thread_state()) { 2104 case _thread_in_vm: 2105 { 2106 JavaThread* THREAD = this; 2107 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2108 } 2109 case _thread_in_native: 2110 { 2111 ThreadInVMfromNative tiv(this); 2112 JavaThread* THREAD = this; 2113 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2114 } 2115 case _thread_in_Java: 2116 { 2117 ThreadInVMfromJava tiv(this); 2118 JavaThread* THREAD = this; 2119 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2120 } 2121 default: 2122 ShouldNotReachHere(); 2123 } 2124 } 2125 2126 assert(condition == _no_async_condition || has_pending_exception() || 2127 (!check_unsafe_error && condition == _async_unsafe_access_error), 2128 "must have handled the async condition, if no exception"); 2129 } 2130 2131 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2132 // 2133 // Check for pending external suspend. Internal suspend requests do 2134 // not use handle_special_runtime_exit_condition(). 2135 // If JNIEnv proxies are allowed, don't self-suspend if the target 2136 // thread is not the current thread. In older versions of jdbx, jdbx 2137 // threads could call into the VM with another thread's JNIEnv so we 2138 // can be here operating on behalf of a suspended thread (4432884). 2139 bool do_self_suspend = is_external_suspend_with_lock(); 2140 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2141 // 2142 // Because thread is external suspended the safepoint code will count 2143 // thread as at a safepoint. This can be odd because we can be here 2144 // as _thread_in_Java which would normally transition to _thread_blocked 2145 // at a safepoint. We would like to mark the thread as _thread_blocked 2146 // before calling java_suspend_self like all other callers of it but 2147 // we must then observe proper safepoint protocol. (We can't leave 2148 // _thread_blocked with a safepoint in progress). However we can be 2149 // here as _thread_in_native_trans so we can't use a normal transition 2150 // constructor/destructor pair because they assert on that type of 2151 // transition. We could do something like: 2152 // 2153 // JavaThreadState state = thread_state(); 2154 // set_thread_state(_thread_in_vm); 2155 // { 2156 // ThreadBlockInVM tbivm(this); 2157 // java_suspend_self() 2158 // } 2159 // set_thread_state(_thread_in_vm_trans); 2160 // if (safepoint) block; 2161 // set_thread_state(state); 2162 // 2163 // but that is pretty messy. Instead we just go with the way the 2164 // code has worked before and note that this is the only path to 2165 // java_suspend_self that doesn't put the thread in _thread_blocked 2166 // mode. 2167 2168 frame_anchor()->make_walkable(this); 2169 java_suspend_self(); 2170 2171 // We might be here for reasons in addition to the self-suspend request 2172 // so check for other async requests. 2173 } 2174 2175 if (check_asyncs) { 2176 check_and_handle_async_exceptions(); 2177 } 2178 } 2179 2180 void JavaThread::send_thread_stop(oop java_throwable) { 2181 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2182 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2183 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2184 2185 // Do not throw asynchronous exceptions against the compiler thread 2186 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2187 if (is_Compiler_thread()) return; 2188 2189 { 2190 // Actually throw the Throwable against the target Thread - however 2191 // only if there is no thread death exception installed already. 2192 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2193 // If the topmost frame is a runtime stub, then we are calling into 2194 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2195 // must deoptimize the caller before continuing, as the compiled exception handler table 2196 // may not be valid 2197 if (has_last_Java_frame()) { 2198 frame f = last_frame(); 2199 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2200 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2201 RegisterMap reg_map(this, UseBiasedLocking); 2202 frame compiled_frame = f.sender(®_map); 2203 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2204 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2205 } 2206 } 2207 } 2208 2209 // Set async. pending exception in thread. 2210 set_pending_async_exception(java_throwable); 2211 2212 if (TraceExceptions) { 2213 ResourceMark rm; 2214 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2215 } 2216 // for AbortVMOnException flag 2217 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2218 } 2219 } 2220 2221 2222 // Interrupt thread so it will wake up from a potential wait() 2223 Thread::interrupt(this); 2224 } 2225 2226 // External suspension mechanism. 2227 // 2228 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2229 // to any VM_locks and it is at a transition 2230 // Self-suspension will happen on the transition out of the vm. 2231 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2232 // 2233 // Guarantees on return: 2234 // + Target thread will not execute any new bytecode (that's why we need to 2235 // force a safepoint) 2236 // + Target thread will not enter any new monitors 2237 // 2238 void JavaThread::java_suspend() { 2239 { MutexLocker mu(Threads_lock); 2240 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2241 return; 2242 } 2243 } 2244 2245 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2246 if (!is_external_suspend()) { 2247 // a racing resume has cancelled us; bail out now 2248 return; 2249 } 2250 2251 // suspend is done 2252 uint32_t debug_bits = 0; 2253 // Warning: is_ext_suspend_completed() may temporarily drop the 2254 // SR_lock to allow the thread to reach a stable thread state if 2255 // it is currently in a transient thread state. 2256 if (is_ext_suspend_completed(false /* !called_by_wait */, 2257 SuspendRetryDelay, &debug_bits) ) { 2258 return; 2259 } 2260 } 2261 2262 VM_ForceSafepoint vm_suspend; 2263 VMThread::execute(&vm_suspend); 2264 } 2265 2266 // Part II of external suspension. 2267 // A JavaThread self suspends when it detects a pending external suspend 2268 // request. This is usually on transitions. It is also done in places 2269 // where continuing to the next transition would surprise the caller, 2270 // e.g., monitor entry. 2271 // 2272 // Returns the number of times that the thread self-suspended. 2273 // 2274 // Note: DO NOT call java_suspend_self() when you just want to block current 2275 // thread. java_suspend_self() is the second stage of cooperative 2276 // suspension for external suspend requests and should only be used 2277 // to complete an external suspend request. 2278 // 2279 int JavaThread::java_suspend_self() { 2280 int ret = 0; 2281 2282 // we are in the process of exiting so don't suspend 2283 if (is_exiting()) { 2284 clear_external_suspend(); 2285 return ret; 2286 } 2287 2288 assert(_anchor.walkable() || 2289 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2290 "must have walkable stack"); 2291 2292 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2293 2294 assert(!this->is_ext_suspended(), 2295 "a thread trying to self-suspend should not already be suspended"); 2296 2297 if (this->is_suspend_equivalent()) { 2298 // If we are self-suspending as a result of the lifting of a 2299 // suspend equivalent condition, then the suspend_equivalent 2300 // flag is not cleared until we set the ext_suspended flag so 2301 // that wait_for_ext_suspend_completion() returns consistent 2302 // results. 2303 this->clear_suspend_equivalent(); 2304 } 2305 2306 // A racing resume may have cancelled us before we grabbed SR_lock 2307 // above. Or another external suspend request could be waiting for us 2308 // by the time we return from SR_lock()->wait(). The thread 2309 // that requested the suspension may already be trying to walk our 2310 // stack and if we return now, we can change the stack out from under 2311 // it. This would be a "bad thing (TM)" and cause the stack walker 2312 // to crash. We stay self-suspended until there are no more pending 2313 // external suspend requests. 2314 while (is_external_suspend()) { 2315 ret++; 2316 this->set_ext_suspended(); 2317 2318 // _ext_suspended flag is cleared by java_resume() 2319 while (is_ext_suspended()) { 2320 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2321 } 2322 } 2323 2324 return ret; 2325 } 2326 2327 #ifdef ASSERT 2328 // verify the JavaThread has not yet been published in the Threads::list, and 2329 // hence doesn't need protection from concurrent access at this stage 2330 void JavaThread::verify_not_published() { 2331 if (!Threads_lock->owned_by_self()) { 2332 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2333 assert( !Threads::includes(this), 2334 "java thread shouldn't have been published yet!"); 2335 } 2336 else { 2337 assert( !Threads::includes(this), 2338 "java thread shouldn't have been published yet!"); 2339 } 2340 } 2341 #endif 2342 2343 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2344 // progress or when _suspend_flags is non-zero. 2345 // Current thread needs to self-suspend if there is a suspend request and/or 2346 // block if a safepoint is in progress. 2347 // Async exception ISN'T checked. 2348 // Note only the ThreadInVMfromNative transition can call this function 2349 // directly and when thread state is _thread_in_native_trans 2350 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2351 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2352 2353 JavaThread *curJT = JavaThread::current(); 2354 bool do_self_suspend = thread->is_external_suspend(); 2355 2356 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2357 2358 // If JNIEnv proxies are allowed, don't self-suspend if the target 2359 // thread is not the current thread. In older versions of jdbx, jdbx 2360 // threads could call into the VM with another thread's JNIEnv so we 2361 // can be here operating on behalf of a suspended thread (4432884). 2362 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2363 JavaThreadState state = thread->thread_state(); 2364 2365 // We mark this thread_blocked state as a suspend-equivalent so 2366 // that a caller to is_ext_suspend_completed() won't be confused. 2367 // The suspend-equivalent state is cleared by java_suspend_self(). 2368 thread->set_suspend_equivalent(); 2369 2370 // If the safepoint code sees the _thread_in_native_trans state, it will 2371 // wait until the thread changes to other thread state. There is no 2372 // guarantee on how soon we can obtain the SR_lock and complete the 2373 // self-suspend request. It would be a bad idea to let safepoint wait for 2374 // too long. Temporarily change the state to _thread_blocked to 2375 // let the VM thread know that this thread is ready for GC. The problem 2376 // of changing thread state is that safepoint could happen just after 2377 // java_suspend_self() returns after being resumed, and VM thread will 2378 // see the _thread_blocked state. We must check for safepoint 2379 // after restoring the state and make sure we won't leave while a safepoint 2380 // is in progress. 2381 thread->set_thread_state(_thread_blocked); 2382 thread->java_suspend_self(); 2383 thread->set_thread_state(state); 2384 // Make sure new state is seen by VM thread 2385 if (os::is_MP()) { 2386 if (UseMembar) { 2387 // Force a fence between the write above and read below 2388 OrderAccess::fence(); 2389 } else { 2390 // Must use this rather than serialization page in particular on Windows 2391 InterfaceSupport::serialize_memory(thread); 2392 } 2393 } 2394 } 2395 2396 if (SafepointSynchronize::do_call_back()) { 2397 // If we are safepointing, then block the caller which may not be 2398 // the same as the target thread (see above). 2399 SafepointSynchronize::block(curJT); 2400 } 2401 2402 if (thread->is_deopt_suspend()) { 2403 thread->clear_deopt_suspend(); 2404 RegisterMap map(thread, false); 2405 frame f = thread->last_frame(); 2406 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2407 f = f.sender(&map); 2408 } 2409 if (f.id() == thread->must_deopt_id()) { 2410 thread->clear_must_deopt_id(); 2411 f.deoptimize(thread); 2412 } else { 2413 fatal("missed deoptimization!"); 2414 } 2415 } 2416 } 2417 2418 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2419 // progress or when _suspend_flags is non-zero. 2420 // Current thread needs to self-suspend if there is a suspend request and/or 2421 // block if a safepoint is in progress. 2422 // Also check for pending async exception (not including unsafe access error). 2423 // Note only the native==>VM/Java barriers can call this function and when 2424 // thread state is _thread_in_native_trans. 2425 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2426 check_safepoint_and_suspend_for_native_trans(thread); 2427 2428 if (thread->has_async_exception()) { 2429 // We are in _thread_in_native_trans state, don't handle unsafe 2430 // access error since that may block. 2431 thread->check_and_handle_async_exceptions(false); 2432 } 2433 } 2434 2435 // This is a variant of the normal 2436 // check_special_condition_for_native_trans with slightly different 2437 // semantics for use by critical native wrappers. It does all the 2438 // normal checks but also performs the transition back into 2439 // thread_in_Java state. This is required so that critical natives 2440 // can potentially block and perform a GC if they are the last thread 2441 // exiting the GC_locker. 2442 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2443 check_special_condition_for_native_trans(thread); 2444 2445 // Finish the transition 2446 thread->set_thread_state(_thread_in_Java); 2447 2448 if (thread->do_critical_native_unlock()) { 2449 ThreadInVMfromJavaNoAsyncException tiv(thread); 2450 GC_locker::unlock_critical(thread); 2451 thread->clear_critical_native_unlock(); 2452 } 2453 } 2454 2455 // We need to guarantee the Threads_lock here, since resumes are not 2456 // allowed during safepoint synchronization 2457 // Can only resume from an external suspension 2458 void JavaThread::java_resume() { 2459 assert_locked_or_safepoint(Threads_lock); 2460 2461 // Sanity check: thread is gone, has started exiting or the thread 2462 // was not externally suspended. 2463 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2464 return; 2465 } 2466 2467 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2468 2469 clear_external_suspend(); 2470 2471 if (is_ext_suspended()) { 2472 clear_ext_suspended(); 2473 SR_lock()->notify_all(); 2474 } 2475 } 2476 2477 void JavaThread::create_stack_guard_pages() { 2478 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2479 address low_addr = stack_base() - stack_size(); 2480 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2481 2482 int allocate = os::allocate_stack_guard_pages(); 2483 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2484 2485 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2486 warning("Attempt to allocate stack guard pages failed."); 2487 return; 2488 } 2489 2490 if (os::guard_memory((char *) low_addr, len)) { 2491 _stack_guard_state = stack_guard_enabled; 2492 } else { 2493 warning("Attempt to protect stack guard pages failed."); 2494 if (os::uncommit_memory((char *) low_addr, len)) { 2495 warning("Attempt to deallocate stack guard pages failed."); 2496 } 2497 } 2498 } 2499 2500 void JavaThread::remove_stack_guard_pages() { 2501 assert(Thread::current() == this, "from different thread"); 2502 if (_stack_guard_state == stack_guard_unused) return; 2503 address low_addr = stack_base() - stack_size(); 2504 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2505 2506 if (os::allocate_stack_guard_pages()) { 2507 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2508 _stack_guard_state = stack_guard_unused; 2509 } else { 2510 warning("Attempt to deallocate stack guard pages failed."); 2511 } 2512 } else { 2513 if (_stack_guard_state == stack_guard_unused) return; 2514 if (os::unguard_memory((char *) low_addr, len)) { 2515 _stack_guard_state = stack_guard_unused; 2516 } else { 2517 warning("Attempt to unprotect stack guard pages failed."); 2518 } 2519 } 2520 } 2521 2522 void JavaThread::enable_stack_yellow_zone() { 2523 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2524 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2525 2526 // The base notation is from the stacks point of view, growing downward. 2527 // We need to adjust it to work correctly with guard_memory() 2528 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2529 2530 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2531 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2532 2533 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2534 _stack_guard_state = stack_guard_enabled; 2535 } else { 2536 warning("Attempt to guard stack yellow zone failed."); 2537 } 2538 enable_register_stack_guard(); 2539 } 2540 2541 void JavaThread::disable_stack_yellow_zone() { 2542 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2543 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2544 2545 // Simply return if called for a thread that does not use guard pages. 2546 if (_stack_guard_state == stack_guard_unused) return; 2547 2548 // The base notation is from the stacks point of view, growing downward. 2549 // We need to adjust it to work correctly with guard_memory() 2550 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2551 2552 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2553 _stack_guard_state = stack_guard_yellow_disabled; 2554 } else { 2555 warning("Attempt to unguard stack yellow zone failed."); 2556 } 2557 disable_register_stack_guard(); 2558 } 2559 2560 void JavaThread::enable_stack_red_zone() { 2561 // The base notation is from the stacks point of view, growing downward. 2562 // We need to adjust it to work correctly with guard_memory() 2563 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2564 address base = stack_red_zone_base() - stack_red_zone_size(); 2565 2566 guarantee(base < stack_base(),"Error calculating stack red zone"); 2567 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2568 2569 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2570 warning("Attempt to guard stack red zone failed."); 2571 } 2572 } 2573 2574 void JavaThread::disable_stack_red_zone() { 2575 // The base notation is from the stacks point of view, growing downward. 2576 // We need to adjust it to work correctly with guard_memory() 2577 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2578 address base = stack_red_zone_base() - stack_red_zone_size(); 2579 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2580 warning("Attempt to unguard stack red zone failed."); 2581 } 2582 } 2583 2584 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2585 // ignore is there is no stack 2586 if (!has_last_Java_frame()) return; 2587 // traverse the stack frames. Starts from top frame. 2588 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2589 frame* fr = fst.current(); 2590 f(fr, fst.register_map()); 2591 } 2592 } 2593 2594 2595 #ifndef PRODUCT 2596 // Deoptimization 2597 // Function for testing deoptimization 2598 void JavaThread::deoptimize() { 2599 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2600 StackFrameStream fst(this, UseBiasedLocking); 2601 bool deopt = false; // Dump stack only if a deopt actually happens. 2602 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2603 // Iterate over all frames in the thread and deoptimize 2604 for(; !fst.is_done(); fst.next()) { 2605 if(fst.current()->can_be_deoptimized()) { 2606 2607 if (only_at) { 2608 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2609 // consists of comma or carriage return separated numbers so 2610 // search for the current bci in that string. 2611 address pc = fst.current()->pc(); 2612 nmethod* nm = (nmethod*) fst.current()->cb(); 2613 ScopeDesc* sd = nm->scope_desc_at( pc); 2614 char buffer[8]; 2615 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2616 size_t len = strlen(buffer); 2617 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2618 while (found != NULL) { 2619 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2620 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2621 // Check that the bci found is bracketed by terminators. 2622 break; 2623 } 2624 found = strstr(found + 1, buffer); 2625 } 2626 if (!found) { 2627 continue; 2628 } 2629 } 2630 2631 if (DebugDeoptimization && !deopt) { 2632 deopt = true; // One-time only print before deopt 2633 tty->print_cr("[BEFORE Deoptimization]"); 2634 trace_frames(); 2635 trace_stack(); 2636 } 2637 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2638 } 2639 } 2640 2641 if (DebugDeoptimization && deopt) { 2642 tty->print_cr("[AFTER Deoptimization]"); 2643 trace_frames(); 2644 } 2645 } 2646 2647 2648 // Make zombies 2649 void JavaThread::make_zombies() { 2650 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2651 if (fst.current()->can_be_deoptimized()) { 2652 // it is a Java nmethod 2653 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2654 nm->make_not_entrant(); 2655 } 2656 } 2657 } 2658 #endif // PRODUCT 2659 2660 2661 void JavaThread::deoptimized_wrt_marked_nmethods() { 2662 if (!has_last_Java_frame()) return; 2663 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2664 StackFrameStream fst(this, UseBiasedLocking); 2665 for(; !fst.is_done(); fst.next()) { 2666 if (fst.current()->should_be_deoptimized()) { 2667 if (LogCompilation && xtty != NULL) { 2668 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2669 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2670 this->name(), nm != NULL ? nm->compile_id() : -1); 2671 } 2672 2673 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2674 } 2675 } 2676 } 2677 2678 2679 // GC support 2680 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2681 2682 void JavaThread::gc_epilogue() { 2683 frames_do(frame_gc_epilogue); 2684 } 2685 2686 2687 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2688 2689 void JavaThread::gc_prologue() { 2690 frames_do(frame_gc_prologue); 2691 } 2692 2693 // If the caller is a NamedThread, then remember, in the current scope, 2694 // the given JavaThread in its _processed_thread field. 2695 class RememberProcessedThread: public StackObj { 2696 NamedThread* _cur_thr; 2697 public: 2698 RememberProcessedThread(JavaThread* jthr) { 2699 Thread* thread = Thread::current(); 2700 if (thread->is_Named_thread()) { 2701 _cur_thr = (NamedThread *)thread; 2702 _cur_thr->set_processed_thread(jthr); 2703 } else { 2704 _cur_thr = NULL; 2705 } 2706 } 2707 2708 ~RememberProcessedThread() { 2709 if (_cur_thr) { 2710 _cur_thr->set_processed_thread(NULL); 2711 } 2712 } 2713 }; 2714 2715 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2716 // Verify that the deferred card marks have been flushed. 2717 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2718 2719 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2720 // since there may be more than one thread using each ThreadProfiler. 2721 2722 // Traverse the GCHandles 2723 Thread::oops_do(f, cld_f, cf); 2724 2725 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2726 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2727 2728 if (has_last_Java_frame()) { 2729 // Record JavaThread to GC thread 2730 RememberProcessedThread rpt(this); 2731 2732 // Traverse the privileged stack 2733 if (_privileged_stack_top != NULL) { 2734 _privileged_stack_top->oops_do(f); 2735 } 2736 2737 // traverse the registered growable array 2738 if (_array_for_gc != NULL) { 2739 for (int index = 0; index < _array_for_gc->length(); index++) { 2740 f->do_oop(_array_for_gc->adr_at(index)); 2741 } 2742 } 2743 2744 // Traverse the monitor chunks 2745 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2746 chunk->oops_do(f); 2747 } 2748 2749 // Traverse the execution stack 2750 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2751 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2752 } 2753 } 2754 2755 // callee_target is never live across a gc point so NULL it here should 2756 // it still contain a methdOop. 2757 2758 set_callee_target(NULL); 2759 2760 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2761 // If we have deferred set_locals there might be oops waiting to be 2762 // written 2763 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2764 if (list != NULL) { 2765 for (int i = 0; i < list->length(); i++) { 2766 list->at(i)->oops_do(f); 2767 } 2768 } 2769 2770 // Traverse instance variables at the end since the GC may be moving things 2771 // around using this function 2772 f->do_oop((oop*) &_threadObj); 2773 f->do_oop((oop*) &_vm_result); 2774 f->do_oop((oop*) &_exception_oop); 2775 f->do_oop((oop*) &_pending_async_exception); 2776 2777 if (jvmti_thread_state() != NULL) { 2778 jvmti_thread_state()->oops_do(f); 2779 } 2780 } 2781 2782 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2783 Thread::nmethods_do(cf); // (super method is a no-op) 2784 2785 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2786 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2787 2788 if (has_last_Java_frame()) { 2789 // Traverse the execution stack 2790 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2791 fst.current()->nmethods_do(cf); 2792 } 2793 } 2794 } 2795 2796 void JavaThread::metadata_do(void f(Metadata*)) { 2797 Thread::metadata_do(f); 2798 if (has_last_Java_frame()) { 2799 // Traverse the execution stack to call f() on the methods in the stack 2800 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2801 fst.current()->metadata_do(f); 2802 } 2803 } else if (is_Compiler_thread()) { 2804 // need to walk ciMetadata in current compile tasks to keep alive. 2805 CompilerThread* ct = (CompilerThread*)this; 2806 if (ct->env() != NULL) { 2807 ct->env()->metadata_do(f); 2808 } 2809 } 2810 } 2811 2812 // Printing 2813 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2814 switch (_thread_state) { 2815 case _thread_uninitialized: return "_thread_uninitialized"; 2816 case _thread_new: return "_thread_new"; 2817 case _thread_new_trans: return "_thread_new_trans"; 2818 case _thread_in_native: return "_thread_in_native"; 2819 case _thread_in_native_trans: return "_thread_in_native_trans"; 2820 case _thread_in_vm: return "_thread_in_vm"; 2821 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2822 case _thread_in_Java: return "_thread_in_Java"; 2823 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2824 case _thread_blocked: return "_thread_blocked"; 2825 case _thread_blocked_trans: return "_thread_blocked_trans"; 2826 default: return "unknown thread state"; 2827 } 2828 } 2829 2830 #ifndef PRODUCT 2831 void JavaThread::print_thread_state_on(outputStream *st) const { 2832 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2833 }; 2834 void JavaThread::print_thread_state() const { 2835 print_thread_state_on(tty); 2836 }; 2837 #endif // PRODUCT 2838 2839 // Called by Threads::print() for VM_PrintThreads operation 2840 void JavaThread::print_on(outputStream *st) const { 2841 st->print("\"%s\" ", get_thread_name()); 2842 oop thread_oop = threadObj(); 2843 if (thread_oop != NULL) { 2844 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2845 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2846 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2847 } 2848 Thread::print_on(st); 2849 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2850 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2851 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2852 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2853 } 2854 #ifndef PRODUCT 2855 print_thread_state_on(st); 2856 _safepoint_state->print_on(st); 2857 #endif // PRODUCT 2858 } 2859 2860 // Called by fatal error handler. The difference between this and 2861 // JavaThread::print() is that we can't grab lock or allocate memory. 2862 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2863 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2864 oop thread_obj = threadObj(); 2865 if (thread_obj != NULL) { 2866 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2867 } 2868 st->print(" ["); 2869 st->print("%s", _get_thread_state_name(_thread_state)); 2870 if (osthread()) { 2871 st->print(", id=%d", osthread()->thread_id()); 2872 } 2873 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2874 _stack_base - _stack_size, _stack_base); 2875 st->print("]"); 2876 return; 2877 } 2878 2879 // Verification 2880 2881 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2882 2883 void JavaThread::verify() { 2884 // Verify oops in the thread. 2885 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2886 2887 // Verify the stack frames. 2888 frames_do(frame_verify); 2889 } 2890 2891 // CR 6300358 (sub-CR 2137150) 2892 // Most callers of this method assume that it can't return NULL but a 2893 // thread may not have a name whilst it is in the process of attaching to 2894 // the VM - see CR 6412693, and there are places where a JavaThread can be 2895 // seen prior to having it's threadObj set (eg JNI attaching threads and 2896 // if vm exit occurs during initialization). These cases can all be accounted 2897 // for such that this method never returns NULL. 2898 const char* JavaThread::get_thread_name() const { 2899 #ifdef ASSERT 2900 // early safepoints can hit while current thread does not yet have TLS 2901 if (!SafepointSynchronize::is_at_safepoint()) { 2902 Thread *cur = Thread::current(); 2903 if (!(cur->is_Java_thread() && cur == this)) { 2904 // Current JavaThreads are allowed to get their own name without 2905 // the Threads_lock. 2906 assert_locked_or_safepoint(Threads_lock); 2907 } 2908 } 2909 #endif // ASSERT 2910 return get_thread_name_string(); 2911 } 2912 2913 // Returns a non-NULL representation of this thread's name, or a suitable 2914 // descriptive string if there is no set name 2915 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2916 const char* name_str; 2917 oop thread_obj = threadObj(); 2918 if (thread_obj != NULL) { 2919 typeArrayOop name = java_lang_Thread::name(thread_obj); 2920 if (name != NULL) { 2921 if (buf == NULL) { 2922 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2923 } 2924 else { 2925 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2926 } 2927 } 2928 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2929 name_str = "<no-name - thread is attaching>"; 2930 } 2931 else { 2932 name_str = Thread::name(); 2933 } 2934 } 2935 else { 2936 name_str = Thread::name(); 2937 } 2938 assert(name_str != NULL, "unexpected NULL thread name"); 2939 return name_str; 2940 } 2941 2942 2943 const char* JavaThread::get_threadgroup_name() const { 2944 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2945 oop thread_obj = threadObj(); 2946 if (thread_obj != NULL) { 2947 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2948 if (thread_group != NULL) { 2949 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2950 // ThreadGroup.name can be null 2951 if (name != NULL) { 2952 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2953 return str; 2954 } 2955 } 2956 } 2957 return NULL; 2958 } 2959 2960 const char* JavaThread::get_parent_name() const { 2961 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2962 oop thread_obj = threadObj(); 2963 if (thread_obj != NULL) { 2964 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2965 if (thread_group != NULL) { 2966 oop parent = java_lang_ThreadGroup::parent(thread_group); 2967 if (parent != NULL) { 2968 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2969 // ThreadGroup.name can be null 2970 if (name != NULL) { 2971 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2972 return str; 2973 } 2974 } 2975 } 2976 } 2977 return NULL; 2978 } 2979 2980 ThreadPriority JavaThread::java_priority() const { 2981 oop thr_oop = threadObj(); 2982 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2983 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2984 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2985 return priority; 2986 } 2987 2988 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2989 2990 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2991 // Link Java Thread object <-> C++ Thread 2992 2993 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2994 // and put it into a new Handle. The Handle "thread_oop" can then 2995 // be used to pass the C++ thread object to other methods. 2996 2997 // Set the Java level thread object (jthread) field of the 2998 // new thread (a JavaThread *) to C++ thread object using the 2999 // "thread_oop" handle. 3000 3001 // Set the thread field (a JavaThread *) of the 3002 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3003 3004 Handle thread_oop(Thread::current(), 3005 JNIHandles::resolve_non_null(jni_thread)); 3006 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3007 "must be initialized"); 3008 set_threadObj(thread_oop()); 3009 java_lang_Thread::set_thread(thread_oop(), this); 3010 3011 if (prio == NoPriority) { 3012 prio = java_lang_Thread::priority(thread_oop()); 3013 assert(prio != NoPriority, "A valid priority should be present"); 3014 } 3015 3016 // Push the Java priority down to the native thread; needs Threads_lock 3017 Thread::set_priority(this, prio); 3018 3019 // Add the new thread to the Threads list and set it in motion. 3020 // We must have threads lock in order to call Threads::add. 3021 // It is crucial that we do not block before the thread is 3022 // added to the Threads list for if a GC happens, then the java_thread oop 3023 // will not be visited by GC. 3024 Threads::add(this); 3025 } 3026 3027 oop JavaThread::current_park_blocker() { 3028 // Support for JSR-166 locks 3029 oop thread_oop = threadObj(); 3030 if (thread_oop != NULL && 3031 JDK_Version::current().supports_thread_park_blocker()) { 3032 return java_lang_Thread::park_blocker(thread_oop); 3033 } 3034 return NULL; 3035 } 3036 3037 3038 void JavaThread::print_stack_on(outputStream* st) { 3039 if (!has_last_Java_frame()) return; 3040 ResourceMark rm; 3041 HandleMark hm; 3042 3043 RegisterMap reg_map(this); 3044 vframe* start_vf = last_java_vframe(®_map); 3045 int count = 0; 3046 for (vframe* f = start_vf; f; f = f->sender() ) { 3047 if (f->is_java_frame()) { 3048 javaVFrame* jvf = javaVFrame::cast(f); 3049 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3050 3051 // Print out lock information 3052 if (JavaMonitorsInStackTrace) { 3053 jvf->print_lock_info_on(st, count); 3054 } 3055 } else { 3056 // Ignore non-Java frames 3057 } 3058 3059 // Bail-out case for too deep stacks 3060 count++; 3061 if (MaxJavaStackTraceDepth == count) return; 3062 } 3063 } 3064 3065 3066 // JVMTI PopFrame support 3067 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3068 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3069 if (in_bytes(size_in_bytes) != 0) { 3070 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3071 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3072 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3073 } 3074 } 3075 3076 void* JavaThread::popframe_preserved_args() { 3077 return _popframe_preserved_args; 3078 } 3079 3080 ByteSize JavaThread::popframe_preserved_args_size() { 3081 return in_ByteSize(_popframe_preserved_args_size); 3082 } 3083 3084 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3085 int sz = in_bytes(popframe_preserved_args_size()); 3086 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3087 return in_WordSize(sz / wordSize); 3088 } 3089 3090 void JavaThread::popframe_free_preserved_args() { 3091 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3092 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3093 _popframe_preserved_args = NULL; 3094 _popframe_preserved_args_size = 0; 3095 } 3096 3097 #ifndef PRODUCT 3098 3099 void JavaThread::trace_frames() { 3100 tty->print_cr("[Describe stack]"); 3101 int frame_no = 1; 3102 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3103 tty->print(" %d. ", frame_no++); 3104 fst.current()->print_value_on(tty,this); 3105 tty->cr(); 3106 } 3107 } 3108 3109 class PrintAndVerifyOopClosure: public OopClosure { 3110 protected: 3111 template <class T> inline void do_oop_work(T* p) { 3112 oop obj = oopDesc::load_decode_heap_oop(p); 3113 if (obj == NULL) return; 3114 tty->print(INTPTR_FORMAT ": ", p); 3115 if (obj->is_oop_or_null()) { 3116 if (obj->is_objArray()) { 3117 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3118 } else { 3119 obj->print(); 3120 } 3121 } else { 3122 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3123 } 3124 tty->cr(); 3125 } 3126 public: 3127 virtual void do_oop(oop* p) { do_oop_work(p); } 3128 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3129 }; 3130 3131 3132 static void oops_print(frame* f, const RegisterMap *map) { 3133 PrintAndVerifyOopClosure print; 3134 f->print_value(); 3135 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3136 } 3137 3138 // Print our all the locations that contain oops and whether they are 3139 // valid or not. This useful when trying to find the oldest frame 3140 // where an oop has gone bad since the frame walk is from youngest to 3141 // oldest. 3142 void JavaThread::trace_oops() { 3143 tty->print_cr("[Trace oops]"); 3144 frames_do(oops_print); 3145 } 3146 3147 3148 #ifdef ASSERT 3149 // Print or validate the layout of stack frames 3150 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3151 ResourceMark rm; 3152 PRESERVE_EXCEPTION_MARK; 3153 FrameValues values; 3154 int frame_no = 0; 3155 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3156 fst.current()->describe(values, ++frame_no); 3157 if (depth == frame_no) break; 3158 } 3159 if (validate_only) { 3160 values.validate(); 3161 } else { 3162 tty->print_cr("[Describe stack layout]"); 3163 values.print(this); 3164 } 3165 } 3166 #endif 3167 3168 void JavaThread::trace_stack_from(vframe* start_vf) { 3169 ResourceMark rm; 3170 int vframe_no = 1; 3171 for (vframe* f = start_vf; f; f = f->sender() ) { 3172 if (f->is_java_frame()) { 3173 javaVFrame::cast(f)->print_activation(vframe_no++); 3174 } else { 3175 f->print(); 3176 } 3177 if (vframe_no > StackPrintLimit) { 3178 tty->print_cr("...<more frames>..."); 3179 return; 3180 } 3181 } 3182 } 3183 3184 3185 void JavaThread::trace_stack() { 3186 if (!has_last_Java_frame()) return; 3187 ResourceMark rm; 3188 HandleMark hm; 3189 RegisterMap reg_map(this); 3190 trace_stack_from(last_java_vframe(®_map)); 3191 } 3192 3193 3194 #endif // PRODUCT 3195 3196 3197 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3198 assert(reg_map != NULL, "a map must be given"); 3199 frame f = last_frame(); 3200 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3201 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3202 } 3203 return NULL; 3204 } 3205 3206 3207 Klass* JavaThread::security_get_caller_class(int depth) { 3208 vframeStream vfst(this); 3209 vfst.security_get_caller_frame(depth); 3210 if (!vfst.at_end()) { 3211 return vfst.method()->method_holder(); 3212 } 3213 return NULL; 3214 } 3215 3216 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3217 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3218 CompileBroker::compiler_thread_loop(); 3219 } 3220 3221 // Create a CompilerThread 3222 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3223 : JavaThread(&compiler_thread_entry) { 3224 _env = NULL; 3225 _log = NULL; 3226 _task = NULL; 3227 _queue = queue; 3228 _counters = counters; 3229 _buffer_blob = NULL; 3230 _scanned_nmethod = NULL; 3231 _compiler = NULL; 3232 3233 #ifndef PRODUCT 3234 _ideal_graph_printer = NULL; 3235 #endif 3236 } 3237 3238 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3239 JavaThread::oops_do(f, cld_f, cf); 3240 if (_scanned_nmethod != NULL && cf != NULL) { 3241 // Safepoints can occur when the sweeper is scanning an nmethod so 3242 // process it here to make sure it isn't unloaded in the middle of 3243 // a scan. 3244 cf->do_code_blob(_scanned_nmethod); 3245 } 3246 } 3247 3248 3249 // ======= Threads ======== 3250 3251 // The Threads class links together all active threads, and provides 3252 // operations over all threads. It is protected by its own Mutex 3253 // lock, which is also used in other contexts to protect thread 3254 // operations from having the thread being operated on from exiting 3255 // and going away unexpectedly (e.g., safepoint synchronization) 3256 3257 JavaThread* Threads::_thread_list = NULL; 3258 int Threads::_number_of_threads = 0; 3259 int Threads::_number_of_non_daemon_threads = 0; 3260 int Threads::_return_code = 0; 3261 size_t JavaThread::_stack_size_at_create = 0; 3262 #ifdef ASSERT 3263 bool Threads::_vm_complete = false; 3264 #endif 3265 3266 // All JavaThreads 3267 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3268 3269 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3270 void Threads::threads_do(ThreadClosure* tc) { 3271 assert_locked_or_safepoint(Threads_lock); 3272 // ALL_JAVA_THREADS iterates through all JavaThreads 3273 ALL_JAVA_THREADS(p) { 3274 tc->do_thread(p); 3275 } 3276 // Someday we could have a table or list of all non-JavaThreads. 3277 // For now, just manually iterate through them. 3278 tc->do_thread(VMThread::vm_thread()); 3279 Universe::heap()->gc_threads_do(tc); 3280 WatcherThread *wt = WatcherThread::watcher_thread(); 3281 // Strictly speaking, the following NULL check isn't sufficient to make sure 3282 // the data for WatcherThread is still valid upon being examined. However, 3283 // considering that WatchThread terminates when the VM is on the way to 3284 // exit at safepoint, the chance of the above is extremely small. The right 3285 // way to prevent termination of WatcherThread would be to acquire 3286 // Terminator_lock, but we can't do that without violating the lock rank 3287 // checking in some cases. 3288 if (wt != NULL) 3289 tc->do_thread(wt); 3290 3291 // If CompilerThreads ever become non-JavaThreads, add them here 3292 } 3293 3294 3295 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3296 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3297 3298 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3299 create_vm_init_libraries(); 3300 } 3301 3302 initialize_class(vmSymbols::java_lang_String(), CHECK); 3303 3304 // Initialize java_lang.System (needed before creating the thread) 3305 initialize_class(vmSymbols::java_lang_System(), CHECK); 3306 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3307 Handle thread_group = create_initial_thread_group(CHECK); 3308 Universe::set_main_thread_group(thread_group()); 3309 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3310 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3311 main_thread->set_threadObj(thread_object); 3312 // Set thread status to running since main thread has 3313 // been started and running. 3314 java_lang_Thread::set_thread_status(thread_object, 3315 java_lang_Thread::RUNNABLE); 3316 3317 // The VM creates & returns objects of this class. Make sure it's initialized. 3318 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3319 3320 // The VM preresolves methods to these classes. Make sure that they get initialized 3321 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3322 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3323 call_initializeSystemClass(CHECK); 3324 3325 // get the Java runtime name after java.lang.System is initialized 3326 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3327 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3328 3329 // an instance of OutOfMemory exception has been allocated earlier 3330 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3331 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3332 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3333 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3334 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3335 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3336 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3337 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3338 } 3339 3340 void Threads::initialize_jsr292_core_classes(TRAPS) { 3341 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3342 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3343 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3344 } 3345 3346 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3347 3348 extern void JDK_Version_init(); 3349 3350 // Check version 3351 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3352 3353 // Initialize the output stream module 3354 ostream_init(); 3355 3356 // Process java launcher properties. 3357 Arguments::process_sun_java_launcher_properties(args); 3358 3359 // Initialize the os module before using TLS 3360 os::init(); 3361 3362 // Initialize system properties. 3363 Arguments::init_system_properties(); 3364 3365 // So that JDK version can be used as a discriminator when parsing arguments 3366 JDK_Version_init(); 3367 3368 // Update/Initialize System properties after JDK version number is known 3369 Arguments::init_version_specific_system_properties(); 3370 3371 // Parse arguments 3372 jint parse_result = Arguments::parse(args); 3373 if (parse_result != JNI_OK) return parse_result; 3374 3375 os::init_before_ergo(); 3376 3377 jint ergo_result = Arguments::apply_ergo(); 3378 if (ergo_result != JNI_OK) return ergo_result; 3379 3380 if (PauseAtStartup) { 3381 os::pause(); 3382 } 3383 3384 HOTSPOT_VM_INIT_BEGIN(); 3385 3386 // Record VM creation timing statistics 3387 TraceVmCreationTime create_vm_timer; 3388 create_vm_timer.start(); 3389 3390 // Timing (must come after argument parsing) 3391 TraceTime timer("Create VM", TraceStartupTime); 3392 3393 // Initialize the os module after parsing the args 3394 jint os_init_2_result = os::init_2(); 3395 if (os_init_2_result != JNI_OK) return os_init_2_result; 3396 3397 jint adjust_after_os_result = Arguments::adjust_after_os(); 3398 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3399 3400 // initialize TLS 3401 ThreadLocalStorage::init(); 3402 3403 // Bootstrap native memory tracking, so it can start recording memory 3404 // activities before worker thread is started. This is the first phase 3405 // of bootstrapping, VM is currently running in single-thread mode. 3406 MemTracker::bootstrap_single_thread(); 3407 3408 // Initialize output stream logging 3409 ostream_init_log(); 3410 3411 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3412 // Must be before create_vm_init_agents() 3413 if (Arguments::init_libraries_at_startup()) { 3414 convert_vm_init_libraries_to_agents(); 3415 } 3416 3417 // Launch -agentlib/-agentpath and converted -Xrun agents 3418 if (Arguments::init_agents_at_startup()) { 3419 create_vm_init_agents(); 3420 } 3421 3422 // Initialize Threads state 3423 _thread_list = NULL; 3424 _number_of_threads = 0; 3425 _number_of_non_daemon_threads = 0; 3426 3427 // Initialize global data structures and create system classes in heap 3428 vm_init_globals(); 3429 3430 // Attach the main thread to this os thread 3431 JavaThread* main_thread = new JavaThread(); 3432 main_thread->set_thread_state(_thread_in_vm); 3433 // must do this before set_active_handles and initialize_thread_local_storage 3434 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3435 // change the stack size recorded here to one based on the java thread 3436 // stacksize. This adjusted size is what is used to figure the placement 3437 // of the guard pages. 3438 main_thread->record_stack_base_and_size(); 3439 main_thread->initialize_thread_local_storage(); 3440 3441 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3442 3443 if (!main_thread->set_as_starting_thread()) { 3444 vm_shutdown_during_initialization( 3445 "Failed necessary internal allocation. Out of swap space"); 3446 delete main_thread; 3447 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3448 return JNI_ENOMEM; 3449 } 3450 3451 // Enable guard page *after* os::create_main_thread(), otherwise it would 3452 // crash Linux VM, see notes in os_linux.cpp. 3453 main_thread->create_stack_guard_pages(); 3454 3455 // Initialize Java-Level synchronization subsystem 3456 ObjectMonitor::Initialize() ; 3457 3458 // Second phase of bootstrapping, VM is about entering multi-thread mode 3459 MemTracker::bootstrap_multi_thread(); 3460 3461 // Initialize global modules 3462 jint status = init_globals(); 3463 if (status != JNI_OK) { 3464 delete main_thread; 3465 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3466 return status; 3467 } 3468 3469 // Should be done after the heap is fully created 3470 main_thread->cache_global_variables(); 3471 3472 HandleMark hm; 3473 3474 { MutexLocker mu(Threads_lock); 3475 Threads::add(main_thread); 3476 } 3477 3478 // Any JVMTI raw monitors entered in onload will transition into 3479 // real raw monitor. VM is setup enough here for raw monitor enter. 3480 JvmtiExport::transition_pending_onload_raw_monitors(); 3481 3482 // Fully start NMT 3483 MemTracker::start(); 3484 3485 // Create the VMThread 3486 { TraceTime timer("Start VMThread", TraceStartupTime); 3487 VMThread::create(); 3488 Thread* vmthread = VMThread::vm_thread(); 3489 3490 if (!os::create_thread(vmthread, os::vm_thread)) 3491 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3492 3493 // Wait for the VM thread to become ready, and VMThread::run to initialize 3494 // Monitors can have spurious returns, must always check another state flag 3495 { 3496 MutexLocker ml(Notify_lock); 3497 os::start_thread(vmthread); 3498 while (vmthread->active_handles() == NULL) { 3499 Notify_lock->wait(); 3500 } 3501 } 3502 } 3503 3504 assert (Universe::is_fully_initialized(), "not initialized"); 3505 if (VerifyDuringStartup) { 3506 // Make sure we're starting with a clean slate. 3507 VM_Verify verify_op; 3508 VMThread::execute(&verify_op); 3509 } 3510 3511 Thread* THREAD = Thread::current(); 3512 3513 // At this point, the Universe is initialized, but we have not executed 3514 // any byte code. Now is a good time (the only time) to dump out the 3515 // internal state of the JVM for sharing. 3516 if (DumpSharedSpaces) { 3517 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3518 ShouldNotReachHere(); 3519 } 3520 3521 // Always call even when there are not JVMTI environments yet, since environments 3522 // may be attached late and JVMTI must track phases of VM execution 3523 JvmtiExport::enter_start_phase(); 3524 3525 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3526 JvmtiExport::post_vm_start(); 3527 3528 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3529 3530 // We need this for ClassDataSharing - the initial vm.info property is set 3531 // with the default value of CDS "sharing" which may be reset through 3532 // command line options. 3533 reset_vm_info_property(CHECK_JNI_ERR); 3534 3535 quicken_jni_functions(); 3536 3537 // Must be run after init_ft which initializes ft_enabled 3538 if (TRACE_INITIALIZE() != JNI_OK) { 3539 vm_exit_during_initialization("Failed to initialize tracing backend"); 3540 } 3541 3542 // Set flag that basic initialization has completed. Used by exceptions and various 3543 // debug stuff, that does not work until all basic classes have been initialized. 3544 set_init_completed(); 3545 3546 HOTSPOT_VM_INIT_END(); 3547 3548 // record VM initialization completion time 3549 #if INCLUDE_MANAGEMENT 3550 Management::record_vm_init_completed(); 3551 #endif // INCLUDE_MANAGEMENT 3552 3553 // Compute system loader. Note that this has to occur after set_init_completed, since 3554 // valid exceptions may be thrown in the process. 3555 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3556 // set_init_completed has just been called, causing exceptions not to be shortcut 3557 // anymore. We call vm_exit_during_initialization directly instead. 3558 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR); 3559 3560 #if INCLUDE_ALL_GCS 3561 // Support for ConcurrentMarkSweep. This should be cleaned up 3562 // and better encapsulated. The ugly nested if test would go away 3563 // once things are properly refactored. XXX YSR 3564 if (UseConcMarkSweepGC || UseG1GC) { 3565 if (UseConcMarkSweepGC) { 3566 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3567 } else { 3568 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3569 } 3570 } 3571 #endif // INCLUDE_ALL_GCS 3572 3573 // Always call even when there are not JVMTI environments yet, since environments 3574 // may be attached late and JVMTI must track phases of VM execution 3575 JvmtiExport::enter_live_phase(); 3576 3577 // Signal Dispatcher needs to be started before VMInit event is posted 3578 os::signal_init(); 3579 3580 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3581 if (!DisableAttachMechanism) { 3582 AttachListener::vm_start(); 3583 if (StartAttachListener || AttachListener::init_at_startup()) { 3584 AttachListener::init(); 3585 } 3586 } 3587 3588 // Launch -Xrun agents 3589 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3590 // back-end can launch with -Xdebug -Xrunjdwp. 3591 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3592 create_vm_init_libraries(); 3593 } 3594 3595 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3596 JvmtiExport::post_vm_initialized(); 3597 3598 if (TRACE_START() != JNI_OK) { 3599 vm_exit_during_initialization("Failed to start tracing backend."); 3600 } 3601 3602 if (CleanChunkPoolAsync) { 3603 Chunk::start_chunk_pool_cleaner_task(); 3604 } 3605 3606 // initialize compiler(s) 3607 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3608 CompileBroker::compilation_init(); 3609 #endif 3610 3611 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3612 // It is done after compilers are initialized, because otherwise compilations of 3613 // signature polymorphic MH intrinsics can be missed 3614 // (see SystemDictionary::find_method_handle_intrinsic). 3615 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3616 3617 #if INCLUDE_MANAGEMENT 3618 Management::initialize(THREAD); 3619 3620 if (HAS_PENDING_EXCEPTION) { 3621 // management agent fails to start possibly due to 3622 // configuration problem and is responsible for printing 3623 // stack trace if appropriate. Simply exit VM. 3624 vm_exit(1); 3625 } 3626 #endif // INCLUDE_MANAGEMENT 3627 3628 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3629 if (MemProfiling) MemProfiler::engage(); 3630 StatSampler::engage(); 3631 if (CheckJNICalls) JniPeriodicChecker::engage(); 3632 3633 BiasedLocking::init(); 3634 3635 #if INCLUDE_RTM_OPT 3636 RTMLockingCounters::init(); 3637 #endif 3638 3639 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3640 call_postVMInitHook(THREAD); 3641 // The Java side of PostVMInitHook.run must deal with all 3642 // exceptions and provide means of diagnosis. 3643 if (HAS_PENDING_EXCEPTION) { 3644 CLEAR_PENDING_EXCEPTION; 3645 } 3646 } 3647 3648 { 3649 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3650 // Make sure the watcher thread can be started by WatcherThread::start() 3651 // or by dynamic enrollment. 3652 WatcherThread::make_startable(); 3653 // Start up the WatcherThread if there are any periodic tasks 3654 // NOTE: All PeriodicTasks should be registered by now. If they 3655 // aren't, late joiners might appear to start slowly (we might 3656 // take a while to process their first tick). 3657 if (PeriodicTask::num_tasks() > 0) { 3658 WatcherThread::start(); 3659 } 3660 } 3661 3662 // Give os specific code one last chance to start 3663 os::init_3(); 3664 3665 create_vm_timer.end(); 3666 #ifdef ASSERT 3667 _vm_complete = true; 3668 #endif 3669 return JNI_OK; 3670 } 3671 3672 // type for the Agent_OnLoad and JVM_OnLoad entry points 3673 extern "C" { 3674 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3675 } 3676 // Find a command line agent library and return its entry point for 3677 // -agentlib: -agentpath: -Xrun 3678 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3679 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3680 OnLoadEntry_t on_load_entry = NULL; 3681 void *library = NULL; 3682 3683 if (!agent->valid()) { 3684 char buffer[JVM_MAXPATHLEN]; 3685 char ebuf[1024]; 3686 const char *name = agent->name(); 3687 const char *msg = "Could not find agent library "; 3688 3689 // First check to see if agent is statically linked into executable 3690 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3691 library = agent->os_lib(); 3692 } else if (agent->is_absolute_path()) { 3693 library = os::dll_load(name, ebuf, sizeof ebuf); 3694 if (library == NULL) { 3695 const char *sub_msg = " in absolute path, with error: "; 3696 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3697 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3698 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3699 // If we can't find the agent, exit. 3700 vm_exit_during_initialization(buf, NULL); 3701 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3702 } 3703 } else { 3704 // Try to load the agent from the standard dll directory 3705 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3706 name)) { 3707 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3708 } 3709 if (library == NULL) { // Try the local directory 3710 char ns[1] = {0}; 3711 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3712 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3713 } 3714 if (library == NULL) { 3715 const char *sub_msg = " on the library path, with error: "; 3716 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3717 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3718 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3719 // If we can't find the agent, exit. 3720 vm_exit_during_initialization(buf, NULL); 3721 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3722 } 3723 } 3724 } 3725 agent->set_os_lib(library); 3726 agent->set_valid(); 3727 } 3728 3729 // Find the OnLoad function. 3730 on_load_entry = 3731 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3732 false, 3733 on_load_symbols, 3734 num_symbol_entries)); 3735 return on_load_entry; 3736 } 3737 3738 // Find the JVM_OnLoad entry point 3739 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3740 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3741 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3742 } 3743 3744 // Find the Agent_OnLoad entry point 3745 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3746 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3747 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3748 } 3749 3750 // For backwards compatibility with -Xrun 3751 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3752 // treated like -agentpath: 3753 // Must be called before agent libraries are created 3754 void Threads::convert_vm_init_libraries_to_agents() { 3755 AgentLibrary* agent; 3756 AgentLibrary* next; 3757 3758 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3759 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3760 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3761 3762 // If there is an JVM_OnLoad function it will get called later, 3763 // otherwise see if there is an Agent_OnLoad 3764 if (on_load_entry == NULL) { 3765 on_load_entry = lookup_agent_on_load(agent); 3766 if (on_load_entry != NULL) { 3767 // switch it to the agent list -- so that Agent_OnLoad will be called, 3768 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3769 Arguments::convert_library_to_agent(agent); 3770 } else { 3771 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3772 } 3773 } 3774 } 3775 } 3776 3777 // Create agents for -agentlib: -agentpath: and converted -Xrun 3778 // Invokes Agent_OnLoad 3779 // Called very early -- before JavaThreads exist 3780 void Threads::create_vm_init_agents() { 3781 extern struct JavaVM_ main_vm; 3782 AgentLibrary* agent; 3783 3784 JvmtiExport::enter_onload_phase(); 3785 3786 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3787 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3788 3789 if (on_load_entry != NULL) { 3790 // Invoke the Agent_OnLoad function 3791 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3792 if (err != JNI_OK) { 3793 vm_exit_during_initialization("agent library failed to init", agent->name()); 3794 } 3795 } else { 3796 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3797 } 3798 } 3799 JvmtiExport::enter_primordial_phase(); 3800 } 3801 3802 extern "C" { 3803 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3804 } 3805 3806 void Threads::shutdown_vm_agents() { 3807 // Send any Agent_OnUnload notifications 3808 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3809 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3810 extern struct JavaVM_ main_vm; 3811 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3812 3813 // Find the Agent_OnUnload function. 3814 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3815 os::find_agent_function(agent, 3816 false, 3817 on_unload_symbols, 3818 num_symbol_entries)); 3819 3820 // Invoke the Agent_OnUnload function 3821 if (unload_entry != NULL) { 3822 JavaThread* thread = JavaThread::current(); 3823 ThreadToNativeFromVM ttn(thread); 3824 HandleMark hm(thread); 3825 (*unload_entry)(&main_vm); 3826 } 3827 } 3828 } 3829 3830 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3831 // Invokes JVM_OnLoad 3832 void Threads::create_vm_init_libraries() { 3833 extern struct JavaVM_ main_vm; 3834 AgentLibrary* agent; 3835 3836 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3837 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3838 3839 if (on_load_entry != NULL) { 3840 // Invoke the JVM_OnLoad function 3841 JavaThread* thread = JavaThread::current(); 3842 ThreadToNativeFromVM ttn(thread); 3843 HandleMark hm(thread); 3844 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3845 if (err != JNI_OK) { 3846 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3847 } 3848 } else { 3849 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3850 } 3851 } 3852 } 3853 3854 // Last thread running calls java.lang.Shutdown.shutdown() 3855 void JavaThread::invoke_shutdown_hooks() { 3856 HandleMark hm(this); 3857 3858 // We could get here with a pending exception, if so clear it now. 3859 if (this->has_pending_exception()) { 3860 this->clear_pending_exception(); 3861 } 3862 3863 EXCEPTION_MARK; 3864 Klass* k = 3865 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3866 THREAD); 3867 if (k != NULL) { 3868 // SystemDictionary::resolve_or_null will return null if there was 3869 // an exception. If we cannot load the Shutdown class, just don't 3870 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3871 // and finalizers (if runFinalizersOnExit is set) won't be run. 3872 // Note that if a shutdown hook was registered or runFinalizersOnExit 3873 // was called, the Shutdown class would have already been loaded 3874 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3875 instanceKlassHandle shutdown_klass (THREAD, k); 3876 JavaValue result(T_VOID); 3877 JavaCalls::call_static(&result, 3878 shutdown_klass, 3879 vmSymbols::shutdown_method_name(), 3880 vmSymbols::void_method_signature(), 3881 THREAD); 3882 } 3883 CLEAR_PENDING_EXCEPTION; 3884 } 3885 3886 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3887 // the program falls off the end of main(). Another VM exit path is through 3888 // vm_exit() when the program calls System.exit() to return a value or when 3889 // there is a serious error in VM. The two shutdown paths are not exactly 3890 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3891 // and VM_Exit op at VM level. 3892 // 3893 // Shutdown sequence: 3894 // + Shutdown native memory tracking if it is on 3895 // + Wait until we are the last non-daemon thread to execute 3896 // <-- every thing is still working at this moment --> 3897 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3898 // shutdown hooks, run finalizers if finalization-on-exit 3899 // + Call before_exit(), prepare for VM exit 3900 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3901 // currently the only user of this mechanism is File.deleteOnExit()) 3902 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3903 // post thread end and vm death events to JVMTI, 3904 // stop signal thread 3905 // + Call JavaThread::exit(), it will: 3906 // > release JNI handle blocks, remove stack guard pages 3907 // > remove this thread from Threads list 3908 // <-- no more Java code from this thread after this point --> 3909 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3910 // the compiler threads at safepoint 3911 // <-- do not use anything that could get blocked by Safepoint --> 3912 // + Disable tracing at JNI/JVM barriers 3913 // + Set _vm_exited flag for threads that are still running native code 3914 // + Delete this thread 3915 // + Call exit_globals() 3916 // > deletes tty 3917 // > deletes PerfMemory resources 3918 // + Return to caller 3919 3920 bool Threads::destroy_vm() { 3921 JavaThread* thread = JavaThread::current(); 3922 3923 #ifdef ASSERT 3924 _vm_complete = false; 3925 #endif 3926 // Wait until we are the last non-daemon thread to execute 3927 { MutexLocker nu(Threads_lock); 3928 while (Threads::number_of_non_daemon_threads() > 1 ) 3929 // This wait should make safepoint checks, wait without a timeout, 3930 // and wait as a suspend-equivalent condition. 3931 // 3932 // Note: If the FlatProfiler is running and this thread is waiting 3933 // for another non-daemon thread to finish, then the FlatProfiler 3934 // is waiting for the external suspend request on this thread to 3935 // complete. wait_for_ext_suspend_completion() will eventually 3936 // timeout, but that takes time. Making this wait a suspend- 3937 // equivalent condition solves that timeout problem. 3938 // 3939 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3940 Mutex::_as_suspend_equivalent_flag); 3941 } 3942 3943 // Hang forever on exit if we are reporting an error. 3944 if (ShowMessageBoxOnError && is_error_reported()) { 3945 os::infinite_sleep(); 3946 } 3947 os::wait_for_keypress_at_exit(); 3948 3949 if (JDK_Version::is_jdk12x_version()) { 3950 // We are the last thread running, so check if finalizers should be run. 3951 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3952 HandleMark rm(thread); 3953 Universe::run_finalizers_on_exit(); 3954 } else { 3955 // run Java level shutdown hooks 3956 thread->invoke_shutdown_hooks(); 3957 } 3958 3959 before_exit(thread); 3960 3961 thread->exit(true); 3962 3963 // Stop VM thread. 3964 { 3965 // 4945125 The vm thread comes to a safepoint during exit. 3966 // GC vm_operations can get caught at the safepoint, and the 3967 // heap is unparseable if they are caught. Grab the Heap_lock 3968 // to prevent this. The GC vm_operations will not be able to 3969 // queue until after the vm thread is dead. 3970 // After this point, we'll never emerge out of the safepoint before 3971 // the VM exits, so concurrent GC threads do not need to be explicitly 3972 // stopped; they remain inactive until the process exits. 3973 // Note: some concurrent G1 threads may be running during a safepoint, 3974 // but these will not be accessing the heap, just some G1-specific side 3975 // data structures that are not accessed by any other threads but them 3976 // after this point in a terminal safepoint. 3977 3978 MutexLocker ml(Heap_lock); 3979 3980 VMThread::wait_for_vm_thread_exit(); 3981 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3982 VMThread::destroy(); 3983 } 3984 3985 // clean up ideal graph printers 3986 #if defined(COMPILER2) && !defined(PRODUCT) 3987 IdealGraphPrinter::clean_up(); 3988 #endif 3989 3990 // Now, all Java threads are gone except daemon threads. Daemon threads 3991 // running Java code or in VM are stopped by the Safepoint. However, 3992 // daemon threads executing native code are still running. But they 3993 // will be stopped at native=>Java/VM barriers. Note that we can't 3994 // simply kill or suspend them, as it is inherently deadlock-prone. 3995 3996 #ifndef PRODUCT 3997 // disable function tracing at JNI/JVM barriers 3998 TraceJNICalls = false; 3999 TraceJVMCalls = false; 4000 TraceRuntimeCalls = false; 4001 #endif 4002 4003 VM_Exit::set_vm_exited(); 4004 4005 notify_vm_shutdown(); 4006 4007 delete thread; 4008 4009 // exit_globals() will delete tty 4010 exit_globals(); 4011 4012 return true; 4013 } 4014 4015 4016 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4017 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4018 return is_supported_jni_version(version); 4019 } 4020 4021 4022 jboolean Threads::is_supported_jni_version(jint version) { 4023 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4024 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4025 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4026 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4027 return JNI_FALSE; 4028 } 4029 4030 4031 void Threads::add(JavaThread* p, bool force_daemon) { 4032 // The threads lock must be owned at this point 4033 assert_locked_or_safepoint(Threads_lock); 4034 4035 // See the comment for this method in thread.hpp for its purpose and 4036 // why it is called here. 4037 p->initialize_queues(); 4038 p->set_next(_thread_list); 4039 _thread_list = p; 4040 _number_of_threads++; 4041 oop threadObj = p->threadObj(); 4042 bool daemon = true; 4043 // Bootstrapping problem: threadObj can be null for initial 4044 // JavaThread (or for threads attached via JNI) 4045 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4046 _number_of_non_daemon_threads++; 4047 daemon = false; 4048 } 4049 4050 p->set_safepoint_visible(true); 4051 4052 ThreadService::add_thread(p, daemon); 4053 4054 // Possible GC point. 4055 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4056 } 4057 4058 void Threads::remove(JavaThread* p) { 4059 // Extra scope needed for Thread_lock, so we can check 4060 // that we do not remove thread without safepoint code notice 4061 { MutexLocker ml(Threads_lock); 4062 4063 assert(includes(p), "p must be present"); 4064 4065 JavaThread* current = _thread_list; 4066 JavaThread* prev = NULL; 4067 4068 while (current != p) { 4069 prev = current; 4070 current = current->next(); 4071 } 4072 4073 if (prev) { 4074 prev->set_next(current->next()); 4075 } else { 4076 _thread_list = p->next(); 4077 } 4078 _number_of_threads--; 4079 oop threadObj = p->threadObj(); 4080 bool daemon = true; 4081 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4082 _number_of_non_daemon_threads--; 4083 daemon = false; 4084 4085 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4086 // on destroy_vm will wake up. 4087 if (number_of_non_daemon_threads() == 1) 4088 Threads_lock->notify_all(); 4089 } 4090 ThreadService::remove_thread(p, daemon); 4091 4092 // Make sure that safepoint code disregard this thread. This is needed since 4093 // the thread might mess around with locks after this point. This can cause it 4094 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4095 // of this thread since it is removed from the queue. 4096 p->set_terminated_value(); 4097 4098 // Now, this thread is not visible to safepoint 4099 p->set_safepoint_visible(false); 4100 // once the thread becomes safepoint invisible, we can not use its per-thread 4101 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4102 // to release its per-thread recorder here. 4103 MemTracker::thread_exiting(p); 4104 } // unlock Threads_lock 4105 4106 // Since Events::log uses a lock, we grab it outside the Threads_lock 4107 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4108 } 4109 4110 // Threads_lock must be held when this is called (or must be called during a safepoint) 4111 bool Threads::includes(JavaThread* p) { 4112 assert(Threads_lock->is_locked(), "sanity check"); 4113 ALL_JAVA_THREADS(q) { 4114 if (q == p ) { 4115 return true; 4116 } 4117 } 4118 return false; 4119 } 4120 4121 // Operations on the Threads list for GC. These are not explicitly locked, 4122 // but the garbage collector must provide a safe context for them to run. 4123 // In particular, these things should never be called when the Threads_lock 4124 // is held by some other thread. (Note: the Safepoint abstraction also 4125 // uses the Threads_lock to guarantee this property. It also makes sure that 4126 // all threads gets blocked when exiting or starting). 4127 4128 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4129 ALL_JAVA_THREADS(p) { 4130 p->oops_do(f, cld_f, cf); 4131 } 4132 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4133 } 4134 4135 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4136 // Introduce a mechanism allowing parallel threads to claim threads as 4137 // root groups. Overhead should be small enough to use all the time, 4138 // even in sequential code. 4139 SharedHeap* sh = SharedHeap::heap(); 4140 // Cannot yet substitute active_workers for n_par_threads 4141 // because of G1CollectedHeap::verify() use of 4142 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4143 // turn off parallelism in process_strong_roots while active_workers 4144 // is being used for parallelism elsewhere. 4145 bool is_par = sh->n_par_threads() > 0; 4146 assert(!is_par || 4147 (SharedHeap::heap()->n_par_threads() == 4148 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4149 int cp = SharedHeap::heap()->strong_roots_parity(); 4150 ALL_JAVA_THREADS(p) { 4151 if (p->claim_oops_do(is_par, cp)) { 4152 p->oops_do(f, cld_f, cf); 4153 } 4154 } 4155 VMThread* vmt = VMThread::vm_thread(); 4156 if (vmt->claim_oops_do(is_par, cp)) { 4157 vmt->oops_do(f, cld_f, cf); 4158 } 4159 } 4160 4161 #if INCLUDE_ALL_GCS 4162 // Used by ParallelScavenge 4163 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4164 ALL_JAVA_THREADS(p) { 4165 q->enqueue(new ThreadRootsTask(p)); 4166 } 4167 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4168 } 4169 4170 // Used by Parallel Old 4171 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4172 ALL_JAVA_THREADS(p) { 4173 q->enqueue(new ThreadRootsMarkingTask(p)); 4174 } 4175 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4176 } 4177 #endif // INCLUDE_ALL_GCS 4178 4179 void Threads::nmethods_do(CodeBlobClosure* cf) { 4180 ALL_JAVA_THREADS(p) { 4181 p->nmethods_do(cf); 4182 } 4183 VMThread::vm_thread()->nmethods_do(cf); 4184 } 4185 4186 void Threads::metadata_do(void f(Metadata*)) { 4187 ALL_JAVA_THREADS(p) { 4188 p->metadata_do(f); 4189 } 4190 } 4191 4192 void Threads::gc_epilogue() { 4193 ALL_JAVA_THREADS(p) { 4194 p->gc_epilogue(); 4195 } 4196 } 4197 4198 void Threads::gc_prologue() { 4199 ALL_JAVA_THREADS(p) { 4200 p->gc_prologue(); 4201 } 4202 } 4203 4204 void Threads::deoptimized_wrt_marked_nmethods() { 4205 ALL_JAVA_THREADS(p) { 4206 p->deoptimized_wrt_marked_nmethods(); 4207 } 4208 } 4209 4210 4211 // Get count Java threads that are waiting to enter the specified monitor. 4212 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4213 address monitor, bool doLock) { 4214 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4215 "must grab Threads_lock or be at safepoint"); 4216 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4217 4218 int i = 0; 4219 { 4220 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4221 ALL_JAVA_THREADS(p) { 4222 if (p->is_Compiler_thread()) continue; 4223 4224 address pending = (address)p->current_pending_monitor(); 4225 if (pending == monitor) { // found a match 4226 if (i < count) result->append(p); // save the first count matches 4227 i++; 4228 } 4229 } 4230 } 4231 return result; 4232 } 4233 4234 4235 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4236 assert(doLock || 4237 Threads_lock->owned_by_self() || 4238 SafepointSynchronize::is_at_safepoint(), 4239 "must grab Threads_lock or be at safepoint"); 4240 4241 // NULL owner means not locked so we can skip the search 4242 if (owner == NULL) return NULL; 4243 4244 { 4245 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4246 ALL_JAVA_THREADS(p) { 4247 // first, see if owner is the address of a Java thread 4248 if (owner == (address)p) return p; 4249 } 4250 } 4251 // Cannot assert on lack of success here since this function may be 4252 // used by code that is trying to report useful problem information 4253 // like deadlock detection. 4254 if (UseHeavyMonitors) return NULL; 4255 4256 // 4257 // If we didn't find a matching Java thread and we didn't force use of 4258 // heavyweight monitors, then the owner is the stack address of the 4259 // Lock Word in the owning Java thread's stack. 4260 // 4261 JavaThread* the_owner = NULL; 4262 { 4263 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4264 ALL_JAVA_THREADS(q) { 4265 if (q->is_lock_owned(owner)) { 4266 the_owner = q; 4267 break; 4268 } 4269 } 4270 } 4271 // cannot assert on lack of success here; see above comment 4272 return the_owner; 4273 } 4274 4275 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4276 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4277 char buf[32]; 4278 st->print_cr("%s", os::local_time_string(buf, sizeof(buf))); 4279 4280 st->print_cr("Full thread dump %s (%s %s):", 4281 Abstract_VM_Version::vm_name(), 4282 Abstract_VM_Version::vm_release(), 4283 Abstract_VM_Version::vm_info_string() 4284 ); 4285 st->cr(); 4286 4287 #if INCLUDE_ALL_GCS 4288 // Dump concurrent locks 4289 ConcurrentLocksDump concurrent_locks; 4290 if (print_concurrent_locks) { 4291 concurrent_locks.dump_at_safepoint(); 4292 } 4293 #endif // INCLUDE_ALL_GCS 4294 4295 ALL_JAVA_THREADS(p) { 4296 ResourceMark rm; 4297 p->print_on(st); 4298 if (print_stacks) { 4299 if (internal_format) { 4300 p->trace_stack(); 4301 } else { 4302 p->print_stack_on(st); 4303 } 4304 } 4305 st->cr(); 4306 #if INCLUDE_ALL_GCS 4307 if (print_concurrent_locks) { 4308 concurrent_locks.print_locks_on(p, st); 4309 } 4310 #endif // INCLUDE_ALL_GCS 4311 } 4312 4313 VMThread::vm_thread()->print_on(st); 4314 st->cr(); 4315 Universe::heap()->print_gc_threads_on(st); 4316 WatcherThread* wt = WatcherThread::watcher_thread(); 4317 if (wt != NULL) { 4318 wt->print_on(st); 4319 st->cr(); 4320 } 4321 CompileBroker::print_compiler_threads_on(st); 4322 st->flush(); 4323 } 4324 4325 // Threads::print_on_error() is called by fatal error handler. It's possible 4326 // that VM is not at safepoint and/or current thread is inside signal handler. 4327 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4328 // memory (even in resource area), it might deadlock the error handler. 4329 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4330 bool found_current = false; 4331 st->print_cr("Java Threads: ( => current thread )"); 4332 ALL_JAVA_THREADS(thread) { 4333 bool is_current = (current == thread); 4334 found_current = found_current || is_current; 4335 4336 st->print("%s", is_current ? "=>" : " "); 4337 4338 st->print(PTR_FORMAT, thread); 4339 st->print(" "); 4340 thread->print_on_error(st, buf, buflen); 4341 st->cr(); 4342 } 4343 st->cr(); 4344 4345 st->print_cr("Other Threads:"); 4346 if (VMThread::vm_thread()) { 4347 bool is_current = (current == VMThread::vm_thread()); 4348 found_current = found_current || is_current; 4349 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4350 4351 st->print(PTR_FORMAT, VMThread::vm_thread()); 4352 st->print(" "); 4353 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4354 st->cr(); 4355 } 4356 WatcherThread* wt = WatcherThread::watcher_thread(); 4357 if (wt != NULL) { 4358 bool is_current = (current == wt); 4359 found_current = found_current || is_current; 4360 st->print("%s", is_current ? "=>" : " "); 4361 4362 st->print(PTR_FORMAT, wt); 4363 st->print(" "); 4364 wt->print_on_error(st, buf, buflen); 4365 st->cr(); 4366 } 4367 if (!found_current) { 4368 st->cr(); 4369 st->print("=>" PTR_FORMAT " (exited) ", current); 4370 current->print_on_error(st, buf, buflen); 4371 st->cr(); 4372 } 4373 } 4374 4375 // Internal SpinLock and Mutex 4376 // Based on ParkEvent 4377 4378 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4379 // 4380 // We employ SpinLocks _only for low-contention, fixed-length 4381 // short-duration critical sections where we're concerned 4382 // about native mutex_t or HotSpot Mutex:: latency. 4383 // The mux construct provides a spin-then-block mutual exclusion 4384 // mechanism. 4385 // 4386 // Testing has shown that contention on the ListLock guarding gFreeList 4387 // is common. If we implement ListLock as a simple SpinLock it's common 4388 // for the JVM to devolve to yielding with little progress. This is true 4389 // despite the fact that the critical sections protected by ListLock are 4390 // extremely short. 4391 // 4392 // TODO-FIXME: ListLock should be of type SpinLock. 4393 // We should make this a 1st-class type, integrated into the lock 4394 // hierarchy as leaf-locks. Critically, the SpinLock structure 4395 // should have sufficient padding to avoid false-sharing and excessive 4396 // cache-coherency traffic. 4397 4398 4399 typedef volatile int SpinLockT ; 4400 4401 void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4402 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4403 return ; // normal fast-path return 4404 } 4405 4406 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4407 TEVENT (SpinAcquire - ctx) ; 4408 int ctr = 0 ; 4409 int Yields = 0 ; 4410 for (;;) { 4411 while (*adr != 0) { 4412 ++ctr ; 4413 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4414 if (Yields > 5) { 4415 os::naked_short_sleep(1); 4416 } else { 4417 os::NakedYield() ; 4418 ++Yields ; 4419 } 4420 } else { 4421 SpinPause() ; 4422 } 4423 } 4424 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4425 } 4426 } 4427 4428 void Thread::SpinRelease (volatile int * adr) { 4429 assert (*adr != 0, "invariant") ; 4430 OrderAccess::fence() ; // guarantee at least release consistency. 4431 // Roach-motel semantics. 4432 // It's safe if subsequent LDs and STs float "up" into the critical section, 4433 // but prior LDs and STs within the critical section can't be allowed 4434 // to reorder or float past the ST that releases the lock. 4435 *adr = 0 ; 4436 } 4437 4438 // muxAcquire and muxRelease: 4439 // 4440 // * muxAcquire and muxRelease support a single-word lock-word construct. 4441 // The LSB of the word is set IFF the lock is held. 4442 // The remainder of the word points to the head of a singly-linked list 4443 // of threads blocked on the lock. 4444 // 4445 // * The current implementation of muxAcquire-muxRelease uses its own 4446 // dedicated Thread._MuxEvent instance. If we're interested in 4447 // minimizing the peak number of extant ParkEvent instances then 4448 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4449 // as certain invariants were satisfied. Specifically, care would need 4450 // to be taken with regards to consuming unpark() "permits". 4451 // A safe rule of thumb is that a thread would never call muxAcquire() 4452 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4453 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4454 // consume an unpark() permit intended for monitorenter, for instance. 4455 // One way around this would be to widen the restricted-range semaphore 4456 // implemented in park(). Another alternative would be to provide 4457 // multiple instances of the PlatformEvent() for each thread. One 4458 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4459 // 4460 // * Usage: 4461 // -- Only as leaf locks 4462 // -- for short-term locking only as muxAcquire does not perform 4463 // thread state transitions. 4464 // 4465 // Alternatives: 4466 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4467 // but with parking or spin-then-park instead of pure spinning. 4468 // * Use Taura-Oyama-Yonenzawa locks. 4469 // * It's possible to construct a 1-0 lock if we encode the lockword as 4470 // (List,LockByte). Acquire will CAS the full lockword while Release 4471 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4472 // acquiring threads use timers (ParkTimed) to detect and recover from 4473 // the stranding window. Thread/Node structures must be aligned on 256-byte 4474 // boundaries by using placement-new. 4475 // * Augment MCS with advisory back-link fields maintained with CAS(). 4476 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4477 // The validity of the backlinks must be ratified before we trust the value. 4478 // If the backlinks are invalid the exiting thread must back-track through the 4479 // the forward links, which are always trustworthy. 4480 // * Add a successor indication. The LockWord is currently encoded as 4481 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4482 // to provide the usual futile-wakeup optimization. 4483 // See RTStt for details. 4484 // * Consider schedctl.sc_nopreempt to cover the critical section. 4485 // 4486 4487 4488 typedef volatile intptr_t MutexT ; // Mux Lock-word 4489 enum MuxBits { LOCKBIT = 1 } ; 4490 4491 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4492 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4493 if (w == 0) return ; 4494 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4495 return ; 4496 } 4497 4498 TEVENT (muxAcquire - Contention) ; 4499 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4500 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4501 for (;;) { 4502 int its = (os::is_MP() ? 100 : 0) + 1 ; 4503 4504 // Optional spin phase: spin-then-park strategy 4505 while (--its >= 0) { 4506 w = *Lock ; 4507 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4508 return ; 4509 } 4510 } 4511 4512 Self->reset() ; 4513 Self->OnList = intptr_t(Lock) ; 4514 // The following fence() isn't _strictly necessary as the subsequent 4515 // CAS() both serializes execution and ratifies the fetched *Lock value. 4516 OrderAccess::fence(); 4517 for (;;) { 4518 w = *Lock ; 4519 if ((w & LOCKBIT) == 0) { 4520 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4521 Self->OnList = 0 ; // hygiene - allows stronger asserts 4522 return ; 4523 } 4524 continue ; // Interference -- *Lock changed -- Just retry 4525 } 4526 assert (w & LOCKBIT, "invariant") ; 4527 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4528 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4529 } 4530 4531 while (Self->OnList != 0) { 4532 Self->park() ; 4533 } 4534 } 4535 } 4536 4537 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4538 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4539 if (w == 0) return ; 4540 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4541 return ; 4542 } 4543 4544 TEVENT (muxAcquire - Contention) ; 4545 ParkEvent * ReleaseAfter = NULL ; 4546 if (ev == NULL) { 4547 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4548 } 4549 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4550 for (;;) { 4551 guarantee (ev->OnList == 0, "invariant") ; 4552 int its = (os::is_MP() ? 100 : 0) + 1 ; 4553 4554 // Optional spin phase: spin-then-park strategy 4555 while (--its >= 0) { 4556 w = *Lock ; 4557 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4558 if (ReleaseAfter != NULL) { 4559 ParkEvent::Release (ReleaseAfter) ; 4560 } 4561 return ; 4562 } 4563 } 4564 4565 ev->reset() ; 4566 ev->OnList = intptr_t(Lock) ; 4567 // The following fence() isn't _strictly necessary as the subsequent 4568 // CAS() both serializes execution and ratifies the fetched *Lock value. 4569 OrderAccess::fence(); 4570 for (;;) { 4571 w = *Lock ; 4572 if ((w & LOCKBIT) == 0) { 4573 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4574 ev->OnList = 0 ; 4575 // We call ::Release while holding the outer lock, thus 4576 // artificially lengthening the critical section. 4577 // Consider deferring the ::Release() until the subsequent unlock(), 4578 // after we've dropped the outer lock. 4579 if (ReleaseAfter != NULL) { 4580 ParkEvent::Release (ReleaseAfter) ; 4581 } 4582 return ; 4583 } 4584 continue ; // Interference -- *Lock changed -- Just retry 4585 } 4586 assert (w & LOCKBIT, "invariant") ; 4587 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4588 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4589 } 4590 4591 while (ev->OnList != 0) { 4592 ev->park() ; 4593 } 4594 } 4595 } 4596 4597 // Release() must extract a successor from the list and then wake that thread. 4598 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4599 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4600 // Release() would : 4601 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4602 // (B) Extract a successor from the private list "in-hand" 4603 // (C) attempt to CAS() the residual back into *Lock over null. 4604 // If there were any newly arrived threads and the CAS() would fail. 4605 // In that case Release() would detach the RATs, re-merge the list in-hand 4606 // with the RATs and repeat as needed. Alternately, Release() might 4607 // detach and extract a successor, but then pass the residual list to the wakee. 4608 // The wakee would be responsible for reattaching and remerging before it 4609 // competed for the lock. 4610 // 4611 // Both "pop" and DMR are immune from ABA corruption -- there can be 4612 // multiple concurrent pushers, but only one popper or detacher. 4613 // This implementation pops from the head of the list. This is unfair, 4614 // but tends to provide excellent throughput as hot threads remain hot. 4615 // (We wake recently run threads first). 4616 4617 void Thread::muxRelease (volatile intptr_t * Lock) { 4618 for (;;) { 4619 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4620 assert (w & LOCKBIT, "invariant") ; 4621 if (w == LOCKBIT) return ; 4622 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4623 assert (List != NULL, "invariant") ; 4624 assert (List->OnList == intptr_t(Lock), "invariant") ; 4625 ParkEvent * nxt = List->ListNext ; 4626 4627 // The following CAS() releases the lock and pops the head element. 4628 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4629 continue ; 4630 } 4631 List->OnList = 0 ; 4632 OrderAccess::fence() ; 4633 List->unpark () ; 4634 return ; 4635 } 4636 } 4637 4638 4639 void Threads::verify() { 4640 ALL_JAVA_THREADS(p) { 4641 p->verify(); 4642 } 4643 VMThread* thread = VMThread::vm_thread(); 4644 if (thread != NULL) thread->verify(); 4645 }