1 /* 2 * Copyright (c) 1997, 2013, 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/aprofiler.hpp" 49 #include "runtime/arguments.hpp" 50 #include "runtime/biasedLocking.hpp" 51 #include "runtime/deoptimization.hpp" 52 #include "runtime/fprofiler.hpp" 53 #include "runtime/frame.inline.hpp" 54 #include "runtime/init.hpp" 55 #include "runtime/interfaceSupport.hpp" 56 #include "runtime/java.hpp" 57 #include "runtime/javaCalls.hpp" 58 #include "runtime/jniPeriodicChecker.hpp" 59 #include "runtime/memprofiler.hpp" 60 #include "runtime/mutexLocker.hpp" 61 #include "runtime/objectMonitor.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/traceEventTypes.hpp" 81 #include "utilities/defaultStream.hpp" 82 #include "utilities/dtrace.hpp" 83 #include "utilities/events.hpp" 84 #include "utilities/preserveException.hpp" 85 #include "utilities/macros.hpp" 86 #ifdef TARGET_OS_FAMILY_linux 87 # include "os_linux.inline.hpp" 88 #endif 89 #ifdef TARGET_OS_FAMILY_solaris 90 # include "os_solaris.inline.hpp" 91 #endif 92 #ifdef TARGET_OS_FAMILY_windows 93 # include "os_windows.inline.hpp" 94 #endif 95 #ifdef TARGET_OS_FAMILY_bsd 96 # include "os_bsd.inline.hpp" 97 #endif 98 #if INCLUDE_ALL_GCS 99 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 100 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 101 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 102 #endif // INCLUDE_ALL_GCS 103 #ifdef COMPILER1 104 #include "c1/c1_Compiler.hpp" 105 #endif 106 #ifdef COMPILER2 107 #include "opto/c2compiler.hpp" 108 #include "opto/idealGraphPrinter.hpp" 109 #endif 110 111 #ifdef DTRACE_ENABLED 112 113 // Only bother with this argument setup if dtrace is available 114 115 #ifndef USDT2 116 HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 117 HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 118 HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 119 intptr_t, intptr_t, bool); 120 HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 121 intptr_t, intptr_t, bool); 122 123 #define DTRACE_THREAD_PROBE(probe, javathread) \ 124 { \ 125 ResourceMark rm(this); \ 126 int len = 0; \ 127 const char* name = (javathread)->get_thread_name(); \ 128 len = strlen(name); \ 129 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 130 name, len, \ 131 java_lang_Thread::thread_id((javathread)->threadObj()), \ 132 (javathread)->osthread()->thread_id(), \ 133 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 134 } 135 136 #else /* USDT2 */ 137 138 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START 139 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP 140 141 #define DTRACE_THREAD_PROBE(probe, javathread) \ 142 { \ 143 ResourceMark rm(this); \ 144 int len = 0; \ 145 const char* name = (javathread)->get_thread_name(); \ 146 len = strlen(name); \ 147 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 148 (char *) name, len, \ 149 java_lang_Thread::thread_id((javathread)->threadObj()), \ 150 (uintptr_t) (javathread)->osthread()->thread_id(), \ 151 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 152 } 153 154 #endif /* USDT2 */ 155 156 #else // ndef DTRACE_ENABLED 157 158 #define DTRACE_THREAD_PROBE(probe, javathread) 159 160 #endif // ndef DTRACE_ENABLED 161 162 163 // Class hierarchy 164 // - Thread 165 // - VMThread 166 // - WatcherThread 167 // - ConcurrentMarkSweepThread 168 // - JavaThread 169 // - CompilerThread 170 171 // ======= Thread ======== 172 // Support for forcing alignment of thread objects for biased locking 173 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 174 if (UseBiasedLocking) { 175 const int alignment = markOopDesc::biased_lock_alignment; 176 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 178 : AllocateHeap(aligned_size, flags, CURRENT_PC, 179 AllocFailStrategy::RETURN_NULL); 180 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 183 "JavaThread alignment code overflowed allocated storage"); 184 if (TraceBiasedLocking) { 185 if (aligned_addr != real_malloc_addr) 186 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 187 real_malloc_addr, aligned_addr); 188 } 189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 190 return aligned_addr; 191 } else { 192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 194 } 195 } 196 197 void Thread::operator delete(void* p) { 198 if (UseBiasedLocking) { 199 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 200 FreeHeap(real_malloc_addr, mtThread); 201 } else { 202 FreeHeap(p, mtThread); 203 } 204 } 205 206 207 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 208 // JavaThread 209 210 211 Thread::Thread() { 212 // stack and get_thread 213 set_stack_base(NULL); 214 set_stack_size(0); 215 set_self_raw_id(0); 216 set_lgrp_id(-1); 217 218 // allocated data structures 219 set_osthread(NULL); 220 set_resource_area(new (mtThread)ResourceArea()); 221 set_handle_area(new (mtThread) HandleArea(NULL)); 222 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(300, true)); 223 set_active_handles(NULL); 224 set_free_handle_block(NULL); 225 set_last_handle_mark(NULL); 226 227 // This initial value ==> never claimed. 228 _oops_do_parity = 0; 229 230 // the handle mark links itself to last_handle_mark 231 new HandleMark(this); 232 233 // plain initialization 234 debug_only(_owned_locks = NULL;) 235 debug_only(_allow_allocation_count = 0;) 236 NOT_PRODUCT(_allow_safepoint_count = 0;) 237 NOT_PRODUCT(_skip_gcalot = false;) 238 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;) 239 _jvmti_env_iteration_count = 0; 240 set_allocated_bytes(0); 241 set_trace_buffer(NULL); 242 _vm_operation_started_count = 0; 243 _vm_operation_completed_count = 0; 244 _current_pending_monitor = NULL; 245 _current_pending_monitor_is_from_java = true; 246 _current_waiting_monitor = NULL; 247 _num_nested_signal = 0; 248 omFreeList = NULL ; 249 omFreeCount = 0 ; 250 omFreeProvision = 32 ; 251 omInUseList = NULL ; 252 omInUseCount = 0 ; 253 254 #ifdef ASSERT 255 _visited_for_critical_count = false; 256 #endif 257 258 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 259 _suspend_flags = 0; 260 261 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 262 _hashStateX = os::random() ; 263 _hashStateY = 842502087 ; 264 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 265 _hashStateW = 273326509 ; 266 267 _OnTrap = 0 ; 268 _schedctl = NULL ; 269 _Stalled = 0 ; 270 _TypeTag = 0x2BAD ; 271 272 // Many of the following fields are effectively final - immutable 273 // Note that nascent threads can't use the Native Monitor-Mutex 274 // construct until the _MutexEvent is initialized ... 275 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 276 // we might instead use a stack of ParkEvents that we could provision on-demand. 277 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 278 // and ::Release() 279 _ParkEvent = ParkEvent::Allocate (this) ; 280 _SleepEvent = ParkEvent::Allocate (this) ; 281 _MutexEvent = ParkEvent::Allocate (this) ; 282 _MuxEvent = ParkEvent::Allocate (this) ; 283 284 #ifdef CHECK_UNHANDLED_OOPS 285 if (CheckUnhandledOops) { 286 _unhandled_oops = new UnhandledOops(this); 287 } 288 #endif // CHECK_UNHANDLED_OOPS 289 #ifdef ASSERT 290 if (UseBiasedLocking) { 291 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 292 assert(this == _real_malloc_address || 293 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 294 "bug in forced alignment of thread objects"); 295 } 296 #endif /* ASSERT */ 297 } 298 299 void Thread::initialize_thread_local_storage() { 300 // Note: Make sure this method only calls 301 // non-blocking operations. Otherwise, it might not work 302 // with the thread-startup/safepoint interaction. 303 304 // During Java thread startup, safepoint code should allow this 305 // method to complete because it may need to allocate memory to 306 // store information for the new thread. 307 308 // initialize structure dependent on thread local storage 309 ThreadLocalStorage::set_thread(this); 310 } 311 312 void Thread::record_stack_base_and_size() { 313 set_stack_base(os::current_stack_base()); 314 set_stack_size(os::current_stack_size()); 315 // CR 7190089: on Solaris, primordial thread's stack is adjusted 316 // in initialize_thread(). Without the adjustment, stack size is 317 // incorrect if stack is set to unlimited (ulimit -s unlimited). 318 // So far, only Solaris has real implementation of initialize_thread(). 319 // 320 // set up any platform-specific state. 321 os::initialize_thread(this); 322 323 #if INCLUDE_NMT 324 // record thread's native stack, stack grows downward 325 address stack_low_addr = stack_base() - stack_size(); 326 NMTTrackOp op(NMTTrackOp::StackAllocOp, this); 327 op.execute_op((address)stack_low_addr, stack_size(), mtThreadStack, CURRENT_PC); 328 #endif // INCLUDE_NMT 329 } 330 331 332 Thread::~Thread() { 333 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 334 ObjectSynchronizer::omFlush (this) ; 335 336 // stack_base can be NULL if the thread is never started or exited before 337 // record_stack_base_and_size called. Although, we would like to ensure 338 // that all started threads do call record_stack_base_and_size(), there is 339 // not proper way to enforce that. 340 #if INCLUDE_NMT 341 if (_stack_base != NULL) { 342 address low_stack_addr = stack_base() - stack_size(); 343 NMTTrackOp op(NMTTrackOp::StackReleaseOp, this); 344 op.execute_op((address)low_stack_addr, stack_size()); 345 #ifdef ASSERT 346 set_stack_base(NULL); 347 #endif 348 } 349 #endif // INCLUDE_NMT 350 351 // deallocate data structures 352 delete resource_area(); 353 // since the handle marks are using the handle area, we have to deallocated the root 354 // handle mark before deallocating the thread's handle area, 355 assert(last_handle_mark() != NULL, "check we have an element"); 356 delete last_handle_mark(); 357 assert(last_handle_mark() == NULL, "check we have reached the end"); 358 359 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 360 // We NULL out the fields for good hygiene. 361 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 362 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 363 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 364 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 365 366 delete handle_area(); 367 delete metadata_handles(); 368 369 // osthread() can be NULL, if creation of thread failed. 370 if (osthread() != NULL) os::free_thread(osthread()); 371 372 delete _SR_lock; 373 374 // clear thread local storage if the Thread is deleting itself 375 if (this == Thread::current()) { 376 ThreadLocalStorage::set_thread(NULL); 377 } else { 378 // In the case where we're not the current thread, invalidate all the 379 // caches in case some code tries to get the current thread or the 380 // thread that was destroyed, and gets stale information. 381 ThreadLocalStorage::invalidate_all(); 382 } 383 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 384 } 385 386 // NOTE: dummy function for assertion purpose. 387 void Thread::run() { 388 ShouldNotReachHere(); 389 } 390 391 #ifdef ASSERT 392 // Private method to check for dangling thread pointer 393 void check_for_dangling_thread_pointer(Thread *thread) { 394 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 395 "possibility of dangling Thread pointer"); 396 } 397 #endif 398 399 400 #ifndef PRODUCT 401 // Tracing method for basic thread operations 402 void Thread::trace(const char* msg, const Thread* const thread) { 403 if (!TraceThreadEvents) return; 404 ResourceMark rm; 405 ThreadCritical tc; 406 const char *name = "non-Java thread"; 407 int prio = -1; 408 if (thread->is_Java_thread() 409 && !thread->is_Compiler_thread()) { 410 // The Threads_lock must be held to get information about 411 // this thread but may not be in some situations when 412 // tracing thread events. 413 bool release_Threads_lock = false; 414 if (!Threads_lock->owned_by_self()) { 415 Threads_lock->lock(); 416 release_Threads_lock = true; 417 } 418 JavaThread* jt = (JavaThread *)thread; 419 name = (char *)jt->get_thread_name(); 420 oop thread_oop = jt->threadObj(); 421 if (thread_oop != NULL) { 422 prio = java_lang_Thread::priority(thread_oop); 423 } 424 if (release_Threads_lock) { 425 Threads_lock->unlock(); 426 } 427 } 428 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 429 } 430 #endif 431 432 433 ThreadPriority Thread::get_priority(const Thread* const thread) { 434 trace("get priority", thread); 435 ThreadPriority priority; 436 // Can return an error! 437 (void)os::get_priority(thread, priority); 438 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 439 return priority; 440 } 441 442 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 443 trace("set priority", thread); 444 debug_only(check_for_dangling_thread_pointer(thread);) 445 // Can return an error! 446 (void)os::set_priority(thread, priority); 447 } 448 449 450 void Thread::start(Thread* thread) { 451 trace("start", thread); 452 // Start is different from resume in that its safety is guaranteed by context or 453 // being called from a Java method synchronized on the Thread object. 454 if (!DisableStartThread) { 455 if (thread->is_Java_thread()) { 456 // Initialize the thread state to RUNNABLE before starting this thread. 457 // Can not set it after the thread started because we do not know the 458 // exact thread state at that time. It could be in MONITOR_WAIT or 459 // in SLEEPING or some other state. 460 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 461 java_lang_Thread::RUNNABLE); 462 } 463 os::start_thread(thread); 464 } 465 } 466 467 // Enqueue a VM_Operation to do the job for us - sometime later 468 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 469 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 470 VMThread::execute(vm_stop); 471 } 472 473 474 // 475 // Check if an external suspend request has completed (or has been 476 // cancelled). Returns true if the thread is externally suspended and 477 // false otherwise. 478 // 479 // The bits parameter returns information about the code path through 480 // the routine. Useful for debugging: 481 // 482 // set in is_ext_suspend_completed(): 483 // 0x00000001 - routine was entered 484 // 0x00000010 - routine return false at end 485 // 0x00000100 - thread exited (return false) 486 // 0x00000200 - suspend request cancelled (return false) 487 // 0x00000400 - thread suspended (return true) 488 // 0x00001000 - thread is in a suspend equivalent state (return true) 489 // 0x00002000 - thread is native and walkable (return true) 490 // 0x00004000 - thread is native_trans and walkable (needed retry) 491 // 492 // set in wait_for_ext_suspend_completion(): 493 // 0x00010000 - routine was entered 494 // 0x00020000 - suspend request cancelled before loop (return false) 495 // 0x00040000 - thread suspended before loop (return true) 496 // 0x00080000 - suspend request cancelled in loop (return false) 497 // 0x00100000 - thread suspended in loop (return true) 498 // 0x00200000 - suspend not completed during retry loop (return false) 499 // 500 501 // Helper class for tracing suspend wait debug bits. 502 // 503 // 0x00000100 indicates that the target thread exited before it could 504 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 505 // 0x00080000 each indicate a cancelled suspend request so they don't 506 // count as wait failures either. 507 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 508 509 class TraceSuspendDebugBits : public StackObj { 510 private: 511 JavaThread * jt; 512 bool is_wait; 513 bool called_by_wait; // meaningful when !is_wait 514 uint32_t * bits; 515 516 public: 517 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 518 uint32_t *_bits) { 519 jt = _jt; 520 is_wait = _is_wait; 521 called_by_wait = _called_by_wait; 522 bits = _bits; 523 } 524 525 ~TraceSuspendDebugBits() { 526 if (!is_wait) { 527 #if 1 528 // By default, don't trace bits for is_ext_suspend_completed() calls. 529 // That trace is very chatty. 530 return; 531 #else 532 if (!called_by_wait) { 533 // If tracing for is_ext_suspend_completed() is enabled, then only 534 // trace calls to it from wait_for_ext_suspend_completion() 535 return; 536 } 537 #endif 538 } 539 540 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 541 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 542 MutexLocker ml(Threads_lock); // needed for get_thread_name() 543 ResourceMark rm; 544 545 tty->print_cr( 546 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 547 jt->get_thread_name(), *bits); 548 549 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 550 } 551 } 552 } 553 }; 554 #undef DEBUG_FALSE_BITS 555 556 557 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 558 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 559 560 bool did_trans_retry = false; // only do thread_in_native_trans retry once 561 bool do_trans_retry; // flag to force the retry 562 563 *bits |= 0x00000001; 564 565 do { 566 do_trans_retry = false; 567 568 if (is_exiting()) { 569 // Thread is in the process of exiting. This is always checked 570 // first to reduce the risk of dereferencing a freed JavaThread. 571 *bits |= 0x00000100; 572 return false; 573 } 574 575 if (!is_external_suspend()) { 576 // Suspend request is cancelled. This is always checked before 577 // is_ext_suspended() to reduce the risk of a rogue resume 578 // confusing the thread that made the suspend request. 579 *bits |= 0x00000200; 580 return false; 581 } 582 583 if (is_ext_suspended()) { 584 // thread is suspended 585 *bits |= 0x00000400; 586 return true; 587 } 588 589 // Now that we no longer do hard suspends of threads running 590 // native code, the target thread can be changing thread state 591 // while we are in this routine: 592 // 593 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 594 // 595 // We save a copy of the thread state as observed at this moment 596 // and make our decision about suspend completeness based on the 597 // copy. This closes the race where the thread state is seen as 598 // _thread_in_native_trans in the if-thread_blocked check, but is 599 // seen as _thread_blocked in if-thread_in_native_trans check. 600 JavaThreadState save_state = thread_state(); 601 602 if (save_state == _thread_blocked && is_suspend_equivalent()) { 603 // If the thread's state is _thread_blocked and this blocking 604 // condition is known to be equivalent to a suspend, then we can 605 // consider the thread to be externally suspended. This means that 606 // the code that sets _thread_blocked has been modified to do 607 // self-suspension if the blocking condition releases. We also 608 // used to check for CONDVAR_WAIT here, but that is now covered by 609 // the _thread_blocked with self-suspension check. 610 // 611 // Return true since we wouldn't be here unless there was still an 612 // external suspend request. 613 *bits |= 0x00001000; 614 return true; 615 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 616 // Threads running native code will self-suspend on native==>VM/Java 617 // transitions. If its stack is walkable (should always be the case 618 // unless this function is called before the actual java_suspend() 619 // call), then the wait is done. 620 *bits |= 0x00002000; 621 return true; 622 } else if (!called_by_wait && !did_trans_retry && 623 save_state == _thread_in_native_trans && 624 frame_anchor()->walkable()) { 625 // The thread is transitioning from thread_in_native to another 626 // thread state. check_safepoint_and_suspend_for_native_trans() 627 // will force the thread to self-suspend. If it hasn't gotten 628 // there yet we may have caught the thread in-between the native 629 // code check above and the self-suspend. Lucky us. If we were 630 // called by wait_for_ext_suspend_completion(), then it 631 // will be doing the retries so we don't have to. 632 // 633 // Since we use the saved thread state in the if-statement above, 634 // there is a chance that the thread has already transitioned to 635 // _thread_blocked by the time we get here. In that case, we will 636 // make a single unnecessary pass through the logic below. This 637 // doesn't hurt anything since we still do the trans retry. 638 639 *bits |= 0x00004000; 640 641 // Once the thread leaves thread_in_native_trans for another 642 // thread state, we break out of this retry loop. We shouldn't 643 // need this flag to prevent us from getting back here, but 644 // sometimes paranoia is good. 645 did_trans_retry = true; 646 647 // We wait for the thread to transition to a more usable state. 648 for (int i = 1; i <= SuspendRetryCount; i++) { 649 // We used to do an "os::yield_all(i)" call here with the intention 650 // that yielding would increase on each retry. However, the parameter 651 // is ignored on Linux which means the yield didn't scale up. Waiting 652 // on the SR_lock below provides a much more predictable scale up for 653 // the delay. It also provides a simple/direct point to check for any 654 // safepoint requests from the VMThread 655 656 // temporarily drops SR_lock while doing wait with safepoint check 657 // (if we're a JavaThread - the WatcherThread can also call this) 658 // and increase delay with each retry 659 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 660 661 // check the actual thread state instead of what we saved above 662 if (thread_state() != _thread_in_native_trans) { 663 // the thread has transitioned to another thread state so 664 // try all the checks (except this one) one more time. 665 do_trans_retry = true; 666 break; 667 } 668 } // end retry loop 669 670 671 } 672 } while (do_trans_retry); 673 674 *bits |= 0x00000010; 675 return false; 676 } 677 678 // 679 // Wait for an external suspend request to complete (or be cancelled). 680 // Returns true if the thread is externally suspended and false otherwise. 681 // 682 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 683 uint32_t *bits) { 684 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 685 false /* !called_by_wait */, bits); 686 687 // local flag copies to minimize SR_lock hold time 688 bool is_suspended; 689 bool pending; 690 uint32_t reset_bits; 691 692 // set a marker so is_ext_suspend_completed() knows we are the caller 693 *bits |= 0x00010000; 694 695 // We use reset_bits to reinitialize the bits value at the top of 696 // each retry loop. This allows the caller to make use of any 697 // unused bits for their own marking purposes. 698 reset_bits = *bits; 699 700 { 701 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 702 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 703 delay, bits); 704 pending = is_external_suspend(); 705 } 706 // must release SR_lock to allow suspension to complete 707 708 if (!pending) { 709 // A cancelled suspend request is the only false return from 710 // is_ext_suspend_completed() that keeps us from entering the 711 // retry loop. 712 *bits |= 0x00020000; 713 return false; 714 } 715 716 if (is_suspended) { 717 *bits |= 0x00040000; 718 return true; 719 } 720 721 for (int i = 1; i <= retries; i++) { 722 *bits = reset_bits; // reinit to only track last retry 723 724 // We used to do an "os::yield_all(i)" call here with the intention 725 // that yielding would increase on each retry. However, the parameter 726 // is ignored on Linux which means the yield didn't scale up. Waiting 727 // on the SR_lock below provides a much more predictable scale up for 728 // the delay. It also provides a simple/direct point to check for any 729 // safepoint requests from the VMThread 730 731 { 732 MutexLocker ml(SR_lock()); 733 // wait with safepoint check (if we're a JavaThread - the WatcherThread 734 // can also call this) and increase delay with each retry 735 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 736 737 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 738 delay, bits); 739 740 // It is possible for the external suspend request to be cancelled 741 // (by a resume) before the actual suspend operation is completed. 742 // Refresh our local copy to see if we still need to wait. 743 pending = is_external_suspend(); 744 } 745 746 if (!pending) { 747 // A cancelled suspend request is the only false return from 748 // is_ext_suspend_completed() that keeps us from staying in the 749 // retry loop. 750 *bits |= 0x00080000; 751 return false; 752 } 753 754 if (is_suspended) { 755 *bits |= 0x00100000; 756 return true; 757 } 758 } // end retry loop 759 760 // thread did not suspend after all our retries 761 *bits |= 0x00200000; 762 return false; 763 } 764 765 #ifndef PRODUCT 766 void JavaThread::record_jump(address target, address instr, const char* file, int line) { 767 768 // This should not need to be atomic as the only way for simultaneous 769 // updates is via interrupts. Even then this should be rare or non-existant 770 // and we don't care that much anyway. 771 772 int index = _jmp_ring_index; 773 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 774 _jmp_ring[index]._target = (intptr_t) target; 775 _jmp_ring[index]._instruction = (intptr_t) instr; 776 _jmp_ring[index]._file = file; 777 _jmp_ring[index]._line = line; 778 } 779 #endif /* PRODUCT */ 780 781 // Called by flat profiler 782 // Callers have already called wait_for_ext_suspend_completion 783 // The assertion for that is currently too complex to put here: 784 bool JavaThread::profile_last_Java_frame(frame* _fr) { 785 bool gotframe = false; 786 // self suspension saves needed state. 787 if (has_last_Java_frame() && _anchor.walkable()) { 788 *_fr = pd_last_frame(); 789 gotframe = true; 790 } 791 return gotframe; 792 } 793 794 void Thread::interrupt(Thread* thread) { 795 trace("interrupt", thread); 796 debug_only(check_for_dangling_thread_pointer(thread);) 797 os::interrupt(thread); 798 } 799 800 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 801 trace("is_interrupted", thread); 802 debug_only(check_for_dangling_thread_pointer(thread);) 803 // Note: If clear_interrupted==false, this simply fetches and 804 // returns the value of the field osthread()->interrupted(). 805 return os::is_interrupted(thread, clear_interrupted); 806 } 807 808 809 // GC Support 810 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 811 jint thread_parity = _oops_do_parity; 812 if (thread_parity != strong_roots_parity) { 813 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 814 if (res == thread_parity) { 815 return true; 816 } else { 817 guarantee(res == strong_roots_parity, "Or else what?"); 818 assert(SharedHeap::heap()->workers()->active_workers() > 0, 819 "Should only fail when parallel."); 820 return false; 821 } 822 } 823 assert(SharedHeap::heap()->workers()->active_workers() > 0, 824 "Should only fail when parallel."); 825 return false; 826 } 827 828 void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 829 active_handles()->oops_do(f); 830 // Do oop for ThreadShadow 831 f->do_oop((oop*)&_pending_exception); 832 handle_area()->oops_do(f); 833 } 834 835 void Thread::nmethods_do(CodeBlobClosure* cf) { 836 // no nmethods in a generic thread... 837 } 838 839 void Thread::metadata_do(void f(Metadata*)) { 840 if (metadata_handles() != NULL) { 841 for (int i = 0; i< metadata_handles()->length(); i++) { 842 f(metadata_handles()->at(i)); 843 } 844 } 845 } 846 847 void Thread::print_on(outputStream* st) const { 848 // get_priority assumes osthread initialized 849 if (osthread() != NULL) { 850 int os_prio; 851 if (os::get_native_priority(this, &os_prio) == OS_OK) { 852 st->print("os_prio=%d ", os_prio); 853 } 854 st->print("tid=" INTPTR_FORMAT " ", this); 855 osthread()->print_on(st); 856 } 857 debug_only(if (WizardMode) print_owned_locks_on(st);) 858 } 859 860 // Thread::print_on_error() is called by fatal error handler. Don't use 861 // any lock or allocate memory. 862 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 863 if (is_VM_thread()) st->print("VMThread"); 864 else if (is_Compiler_thread()) st->print("CompilerThread"); 865 else if (is_Java_thread()) st->print("JavaThread"); 866 else if (is_GC_task_thread()) st->print("GCTaskThread"); 867 else if (is_Watcher_thread()) st->print("WatcherThread"); 868 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 869 else st->print("Thread"); 870 871 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 872 _stack_base - _stack_size, _stack_base); 873 874 if (osthread()) { 875 st->print(" [id=%d]", osthread()->thread_id()); 876 } 877 } 878 879 #ifdef ASSERT 880 void Thread::print_owned_locks_on(outputStream* st) const { 881 Monitor *cur = _owned_locks; 882 if (cur == NULL) { 883 st->print(" (no locks) "); 884 } else { 885 st->print_cr(" Locks owned:"); 886 while(cur) { 887 cur->print_on(st); 888 cur = cur->next(); 889 } 890 } 891 } 892 893 static int ref_use_count = 0; 894 895 bool Thread::owns_locks_but_compiled_lock() const { 896 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 897 if (cur != Compile_lock) return true; 898 } 899 return false; 900 } 901 902 903 #endif 904 905 #ifndef PRODUCT 906 907 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 908 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 909 // no threads which allow_vm_block's are held 910 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 911 // Check if current thread is allowed to block at a safepoint 912 if (!(_allow_safepoint_count == 0)) 913 fatal("Possible safepoint reached by thread that does not allow it"); 914 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 915 fatal("LEAF method calling lock?"); 916 } 917 918 #ifdef ASSERT 919 if (potential_vm_operation && is_Java_thread() 920 && !Universe::is_bootstrapping()) { 921 // Make sure we do not hold any locks that the VM thread also uses. 922 // This could potentially lead to deadlocks 923 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 924 // Threads_lock is special, since the safepoint synchronization will not start before this is 925 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 926 // since it is used to transfer control between JavaThreads and the VMThread 927 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first! 928 if ( (cur->allow_vm_block() && 929 cur != Threads_lock && 930 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation 931 cur != VMOperationRequest_lock && 932 cur != VMOperationQueue_lock) || 933 cur->rank() == Mutex::special) { 934 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 935 } 936 } 937 } 938 939 if (GCALotAtAllSafepoints) { 940 // We could enter a safepoint here and thus have a gc 941 InterfaceSupport::check_gc_alot(); 942 } 943 #endif 944 } 945 #endif 946 947 bool Thread::is_in_stack(address adr) const { 948 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 949 address end = os::current_stack_pointer(); 950 // Allow non Java threads to call this without stack_base 951 if (_stack_base == NULL) return true; 952 if (stack_base() >= adr && adr >= end) return true; 953 954 return false; 955 } 956 957 958 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 959 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 960 // used for compilation in the future. If that change is made, the need for these methods 961 // should be revisited, and they should be removed if possible. 962 963 bool Thread::is_lock_owned(address adr) const { 964 return on_local_stack(adr); 965 } 966 967 bool Thread::set_as_starting_thread() { 968 // NOTE: this must be called inside the main thread. 969 return os::create_main_thread((JavaThread*)this); 970 } 971 972 static void initialize_class(Symbol* class_name, TRAPS) { 973 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 974 InstanceKlass::cast(klass)->initialize(CHECK); 975 } 976 977 978 // Creates the initial ThreadGroup 979 static Handle create_initial_thread_group(TRAPS) { 980 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 981 instanceKlassHandle klass (THREAD, k); 982 983 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 984 { 985 JavaValue result(T_VOID); 986 JavaCalls::call_special(&result, 987 system_instance, 988 klass, 989 vmSymbols::object_initializer_name(), 990 vmSymbols::void_method_signature(), 991 CHECK_NH); 992 } 993 Universe::set_system_thread_group(system_instance()); 994 995 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 996 { 997 JavaValue result(T_VOID); 998 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 999 JavaCalls::call_special(&result, 1000 main_instance, 1001 klass, 1002 vmSymbols::object_initializer_name(), 1003 vmSymbols::threadgroup_string_void_signature(), 1004 system_instance, 1005 string, 1006 CHECK_NH); 1007 } 1008 return main_instance; 1009 } 1010 1011 // Creates the initial Thread 1012 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1013 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1014 instanceKlassHandle klass (THREAD, k); 1015 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1016 1017 java_lang_Thread::set_thread(thread_oop(), thread); 1018 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1019 thread->set_threadObj(thread_oop()); 1020 1021 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1022 1023 JavaValue result(T_VOID); 1024 JavaCalls::call_special(&result, thread_oop, 1025 klass, 1026 vmSymbols::object_initializer_name(), 1027 vmSymbols::threadgroup_string_void_signature(), 1028 thread_group, 1029 string, 1030 CHECK_NULL); 1031 return thread_oop(); 1032 } 1033 1034 static void call_initializeSystemClass(TRAPS) { 1035 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1036 instanceKlassHandle klass (THREAD, k); 1037 1038 JavaValue result(T_VOID); 1039 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1040 vmSymbols::void_method_signature(), CHECK); 1041 } 1042 1043 char java_runtime_name[128] = ""; 1044 char java_runtime_version[128] = ""; 1045 1046 // extract the JRE name from sun.misc.Version.java_runtime_name 1047 static const char* get_java_runtime_name(TRAPS) { 1048 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1049 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1050 fieldDescriptor fd; 1051 bool found = k != NULL && 1052 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1053 vmSymbols::string_signature(), &fd); 1054 if (found) { 1055 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1056 if (name_oop == NULL) 1057 return NULL; 1058 const char* name = java_lang_String::as_utf8_string(name_oop, 1059 java_runtime_name, 1060 sizeof(java_runtime_name)); 1061 return name; 1062 } else { 1063 return NULL; 1064 } 1065 } 1066 1067 // extract the JRE version from sun.misc.Version.java_runtime_version 1068 static const char* get_java_runtime_version(TRAPS) { 1069 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1070 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1071 fieldDescriptor fd; 1072 bool found = k != NULL && 1073 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1074 vmSymbols::string_signature(), &fd); 1075 if (found) { 1076 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1077 if (name_oop == NULL) 1078 return NULL; 1079 const char* name = java_lang_String::as_utf8_string(name_oop, 1080 java_runtime_version, 1081 sizeof(java_runtime_version)); 1082 return name; 1083 } else { 1084 return NULL; 1085 } 1086 } 1087 1088 // General purpose hook into Java code, run once when the VM is initialized. 1089 // The Java library method itself may be changed independently from the VM. 1090 static void call_postVMInitHook(TRAPS) { 1091 Klass* k = SystemDictionary::PostVMInitHook_klass(); 1092 instanceKlassHandle klass (THREAD, k); 1093 if (klass.not_null()) { 1094 JavaValue result(T_VOID); 1095 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1096 vmSymbols::void_method_signature(), 1097 CHECK); 1098 } 1099 } 1100 1101 static void reset_vm_info_property(TRAPS) { 1102 // the vm info string 1103 ResourceMark rm(THREAD); 1104 const char *vm_info = VM_Version::vm_info_string(); 1105 1106 // java.lang.System class 1107 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1108 instanceKlassHandle klass (THREAD, k); 1109 1110 // setProperty arguments 1111 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1112 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1113 1114 // return value 1115 JavaValue r(T_OBJECT); 1116 1117 // public static String setProperty(String key, String value); 1118 JavaCalls::call_static(&r, 1119 klass, 1120 vmSymbols::setProperty_name(), 1121 vmSymbols::string_string_string_signature(), 1122 key_str, 1123 value_str, 1124 CHECK); 1125 } 1126 1127 1128 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1129 assert(thread_group.not_null(), "thread group should be specified"); 1130 assert(threadObj() == NULL, "should only create Java thread object once"); 1131 1132 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1133 instanceKlassHandle klass (THREAD, k); 1134 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1135 1136 java_lang_Thread::set_thread(thread_oop(), this); 1137 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1138 set_threadObj(thread_oop()); 1139 1140 JavaValue result(T_VOID); 1141 if (thread_name != NULL) { 1142 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1143 // Thread gets assigned specified name and null target 1144 JavaCalls::call_special(&result, 1145 thread_oop, 1146 klass, 1147 vmSymbols::object_initializer_name(), 1148 vmSymbols::threadgroup_string_void_signature(), 1149 thread_group, // Argument 1 1150 name, // Argument 2 1151 THREAD); 1152 } else { 1153 // Thread gets assigned name "Thread-nnn" and null target 1154 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1155 JavaCalls::call_special(&result, 1156 thread_oop, 1157 klass, 1158 vmSymbols::object_initializer_name(), 1159 vmSymbols::threadgroup_runnable_void_signature(), 1160 thread_group, // Argument 1 1161 Handle(), // Argument 2 1162 THREAD); 1163 } 1164 1165 1166 if (daemon) { 1167 java_lang_Thread::set_daemon(thread_oop()); 1168 } 1169 1170 if (HAS_PENDING_EXCEPTION) { 1171 return; 1172 } 1173 1174 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1175 Handle threadObj(this, this->threadObj()); 1176 1177 JavaCalls::call_special(&result, 1178 thread_group, 1179 group, 1180 vmSymbols::add_method_name(), 1181 vmSymbols::thread_void_signature(), 1182 threadObj, // Arg 1 1183 THREAD); 1184 1185 1186 } 1187 1188 // NamedThread -- non-JavaThread subclasses with multiple 1189 // uniquely named instances should derive from this. 1190 NamedThread::NamedThread() : Thread() { 1191 _name = NULL; 1192 _processed_thread = NULL; 1193 } 1194 1195 NamedThread::~NamedThread() { 1196 if (_name != NULL) { 1197 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1198 _name = NULL; 1199 } 1200 } 1201 1202 void NamedThread::set_name(const char* format, ...) { 1203 guarantee(_name == NULL, "Only get to set name once."); 1204 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1205 guarantee(_name != NULL, "alloc failure"); 1206 va_list ap; 1207 va_start(ap, format); 1208 jio_vsnprintf(_name, max_name_len, format, ap); 1209 va_end(ap); 1210 } 1211 1212 // ======= WatcherThread ======== 1213 1214 // The watcher thread exists to simulate timer interrupts. It should 1215 // be replaced by an abstraction over whatever native support for 1216 // timer interrupts exists on the platform. 1217 1218 WatcherThread* WatcherThread::_watcher_thread = NULL; 1219 bool WatcherThread::_startable = false; 1220 volatile bool WatcherThread::_should_terminate = false; 1221 1222 WatcherThread::WatcherThread() : Thread() { 1223 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1224 if (os::create_thread(this, os::watcher_thread)) { 1225 _watcher_thread = this; 1226 1227 // Set the watcher thread to the highest OS priority which should not be 1228 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1229 // is created. The only normal thread using this priority is the reference 1230 // handler thread, which runs for very short intervals only. 1231 // If the VMThread's priority is not lower than the WatcherThread profiling 1232 // will be inaccurate. 1233 os::set_priority(this, MaxPriority); 1234 if (!DisableStartThread) { 1235 os::start_thread(this); 1236 } 1237 } 1238 } 1239 1240 int WatcherThread::sleep() const { 1241 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1242 1243 // remaining will be zero if there are no tasks, 1244 // causing the WatcherThread to sleep until a task is 1245 // enrolled 1246 int remaining = PeriodicTask::time_to_wait(); 1247 int time_slept = 0; 1248 1249 // we expect this to timeout - we only ever get unparked when 1250 // we should terminate or when a new task has been enrolled 1251 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1252 1253 jlong time_before_loop = os::javaTimeNanos(); 1254 1255 for (;;) { 1256 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1257 jlong now = os::javaTimeNanos(); 1258 1259 if (remaining == 0) { 1260 // if we didn't have any tasks we could have waited for a long time 1261 // consider the time_slept zero and reset time_before_loop 1262 time_slept = 0; 1263 time_before_loop = now; 1264 } else { 1265 // need to recalulate since we might have new tasks in _tasks 1266 time_slept = (int) ((now - time_before_loop) / 1000000); 1267 } 1268 1269 // Change to task list or spurious wakeup of some kind 1270 if (timedout || _should_terminate) { 1271 break; 1272 } 1273 1274 remaining = PeriodicTask::time_to_wait(); 1275 if (remaining == 0) { 1276 // Last task was just disenrolled so loop around and wait until 1277 // another task gets enrolled 1278 continue; 1279 } 1280 1281 remaining -= time_slept; 1282 if (remaining <= 0) 1283 break; 1284 } 1285 1286 return time_slept; 1287 } 1288 1289 void WatcherThread::run() { 1290 assert(this == watcher_thread(), "just checking"); 1291 1292 this->record_stack_base_and_size(); 1293 this->initialize_thread_local_storage(); 1294 this->set_active_handles(JNIHandleBlock::allocate_block()); 1295 while(!_should_terminate) { 1296 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1297 assert(watcher_thread() == this, "thread consistency check"); 1298 1299 // Calculate how long it'll be until the next PeriodicTask work 1300 // should be done, and sleep that amount of time. 1301 int time_waited = sleep(); 1302 1303 if (is_error_reported()) { 1304 // A fatal error has happened, the error handler(VMError::report_and_die) 1305 // should abort JVM after creating an error log file. However in some 1306 // rare cases, the error handler itself might deadlock. Here we try to 1307 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1308 // 1309 // This code is in WatcherThread because WatcherThread wakes up 1310 // periodically so the fatal error handler doesn't need to do anything; 1311 // also because the WatcherThread is less likely to crash than other 1312 // threads. 1313 1314 for (;;) { 1315 if (!ShowMessageBoxOnError 1316 && (OnError == NULL || OnError[0] == '\0') 1317 && Arguments::abort_hook() == NULL) { 1318 os::sleep(this, 2 * 60 * 1000, false); 1319 fdStream err(defaultStream::output_fd()); 1320 err.print_raw_cr("# [ timer expired, abort... ]"); 1321 // skip atexit/vm_exit/vm_abort hooks 1322 os::die(); 1323 } 1324 1325 // Wake up 5 seconds later, the fatal handler may reset OnError or 1326 // ShowMessageBoxOnError when it is ready to abort. 1327 os::sleep(this, 5 * 1000, false); 1328 } 1329 } 1330 1331 PeriodicTask::real_time_tick(time_waited); 1332 } 1333 1334 // Signal that it is terminated 1335 { 1336 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1337 _watcher_thread = NULL; 1338 Terminator_lock->notify(); 1339 } 1340 1341 // Thread destructor usually does this.. 1342 ThreadLocalStorage::set_thread(NULL); 1343 } 1344 1345 void WatcherThread::start() { 1346 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1347 1348 if (watcher_thread() == NULL && _startable) { 1349 _should_terminate = false; 1350 // Create the single instance of WatcherThread 1351 new WatcherThread(); 1352 } 1353 } 1354 1355 void WatcherThread::make_startable() { 1356 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1357 _startable = true; 1358 } 1359 1360 void WatcherThread::stop() { 1361 { 1362 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1363 _should_terminate = true; 1364 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1365 1366 WatcherThread* watcher = watcher_thread(); 1367 if (watcher != NULL) 1368 watcher->unpark(); 1369 } 1370 1371 // it is ok to take late safepoints here, if needed 1372 MutexLocker mu(Terminator_lock); 1373 1374 while(watcher_thread() != NULL) { 1375 // This wait should make safepoint checks, wait without a timeout, 1376 // and wait as a suspend-equivalent condition. 1377 // 1378 // Note: If the FlatProfiler is running, then this thread is waiting 1379 // for the WatcherThread to terminate and the WatcherThread, via the 1380 // FlatProfiler task, is waiting for the external suspend request on 1381 // this thread to complete. wait_for_ext_suspend_completion() will 1382 // eventually timeout, but that takes time. Making this wait a 1383 // suspend-equivalent condition solves that timeout problem. 1384 // 1385 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1386 Mutex::_as_suspend_equivalent_flag); 1387 } 1388 } 1389 1390 void WatcherThread::unpark() { 1391 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1392 PeriodicTask_lock->notify(); 1393 } 1394 1395 void WatcherThread::print_on(outputStream* st) const { 1396 st->print("\"%s\" ", name()); 1397 Thread::print_on(st); 1398 st->cr(); 1399 } 1400 1401 // ======= JavaThread ======== 1402 1403 // A JavaThread is a normal Java thread 1404 1405 void JavaThread::initialize() { 1406 // Initialize fields 1407 1408 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1409 set_claimed_par_id(-1); 1410 1411 set_saved_exception_pc(NULL); 1412 set_threadObj(NULL); 1413 _anchor.clear(); 1414 set_entry_point(NULL); 1415 set_jni_functions(jni_functions()); 1416 set_callee_target(NULL); 1417 set_vm_result(NULL); 1418 set_vm_result_2(NULL); 1419 set_vframe_array_head(NULL); 1420 set_vframe_array_last(NULL); 1421 set_deferred_locals(NULL); 1422 set_deopt_mark(NULL); 1423 set_deopt_nmethod(NULL); 1424 clear_must_deopt_id(); 1425 set_monitor_chunks(NULL); 1426 set_next(NULL); 1427 set_thread_state(_thread_new); 1428 #if INCLUDE_NMT 1429 set_recorder(NULL); 1430 #endif 1431 _terminated = _not_terminated; 1432 _privileged_stack_top = NULL; 1433 _array_for_gc = NULL; 1434 _suspend_equivalent = false; 1435 _in_deopt_handler = 0; 1436 _doing_unsafe_access = false; 1437 _stack_guard_state = stack_guard_unused; 1438 _exception_oop = NULL; 1439 _exception_pc = 0; 1440 _exception_handler_pc = 0; 1441 _is_method_handle_return = 0; 1442 _jvmti_thread_state= NULL; 1443 _should_post_on_exceptions_flag = JNI_FALSE; 1444 _jvmti_get_loaded_classes_closure = NULL; 1445 _interp_only_mode = 0; 1446 _special_runtime_exit_condition = _no_async_condition; 1447 _pending_async_exception = NULL; 1448 _is_compiling = false; 1449 _thread_stat = NULL; 1450 _thread_stat = new ThreadStatistics(); 1451 _blocked_on_compilation = false; 1452 _jni_active_critical = 0; 1453 _do_not_unlock_if_synchronized = false; 1454 _cached_monitor_info = NULL; 1455 _parker = Parker::Allocate(this) ; 1456 1457 #ifndef PRODUCT 1458 _jmp_ring_index = 0; 1459 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1460 record_jump(NULL, NULL, NULL, 0); 1461 } 1462 #endif /* PRODUCT */ 1463 1464 set_thread_profiler(NULL); 1465 if (FlatProfiler::is_active()) { 1466 // This is where we would decide to either give each thread it's own profiler 1467 // or use one global one from FlatProfiler, 1468 // or up to some count of the number of profiled threads, etc. 1469 ThreadProfiler* pp = new ThreadProfiler(); 1470 pp->engage(); 1471 set_thread_profiler(pp); 1472 } 1473 1474 // Setup safepoint state info for this thread 1475 ThreadSafepointState::create(this); 1476 1477 debug_only(_java_call_counter = 0); 1478 1479 // JVMTI PopFrame support 1480 _popframe_condition = popframe_inactive; 1481 _popframe_preserved_args = NULL; 1482 _popframe_preserved_args_size = 0; 1483 1484 pd_initialize(); 1485 } 1486 1487 #if INCLUDE_ALL_GCS 1488 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1489 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1490 #endif // INCLUDE_ALL_GCS 1491 1492 JavaThread::JavaThread(bool is_attaching_via_jni) : 1493 Thread() 1494 #if INCLUDE_ALL_GCS 1495 , _satb_mark_queue(&_satb_mark_queue_set), 1496 _dirty_card_queue(&_dirty_card_queue_set) 1497 #endif // INCLUDE_ALL_GCS 1498 { 1499 initialize(); 1500 if (is_attaching_via_jni) { 1501 _jni_attach_state = _attaching_via_jni; 1502 } else { 1503 _jni_attach_state = _not_attaching_via_jni; 1504 } 1505 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1506 _safepoint_visible = false; 1507 } 1508 1509 bool JavaThread::reguard_stack(address cur_sp) { 1510 if (_stack_guard_state != stack_guard_yellow_disabled) { 1511 return true; // Stack already guarded or guard pages not needed. 1512 } 1513 1514 if (register_stack_overflow()) { 1515 // For those architectures which have separate register and 1516 // memory stacks, we must check the register stack to see if 1517 // it has overflowed. 1518 return false; 1519 } 1520 1521 // Java code never executes within the yellow zone: the latter is only 1522 // there to provoke an exception during stack banging. If java code 1523 // is executing there, either StackShadowPages should be larger, or 1524 // some exception code in c1, c2 or the interpreter isn't unwinding 1525 // when it should. 1526 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1527 1528 enable_stack_yellow_zone(); 1529 return true; 1530 } 1531 1532 bool JavaThread::reguard_stack(void) { 1533 return reguard_stack(os::current_stack_pointer()); 1534 } 1535 1536 1537 void JavaThread::block_if_vm_exited() { 1538 if (_terminated == _vm_exited) { 1539 // _vm_exited is set at safepoint, and Threads_lock is never released 1540 // we will block here forever 1541 Threads_lock->lock_without_safepoint_check(); 1542 ShouldNotReachHere(); 1543 } 1544 } 1545 1546 1547 // Remove this ifdef when C1 is ported to the compiler interface. 1548 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1549 1550 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1551 Thread() 1552 #if INCLUDE_ALL_GCS 1553 , _satb_mark_queue(&_satb_mark_queue_set), 1554 _dirty_card_queue(&_dirty_card_queue_set) 1555 #endif // INCLUDE_ALL_GCS 1556 { 1557 if (TraceThreadEvents) { 1558 tty->print_cr("creating thread %p", this); 1559 } 1560 initialize(); 1561 _jni_attach_state = _not_attaching_via_jni; 1562 set_entry_point(entry_point); 1563 // Create the native thread itself. 1564 // %note runtime_23 1565 os::ThreadType thr_type = os::java_thread; 1566 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1567 os::java_thread; 1568 os::create_thread(this, thr_type, stack_sz); 1569 _safepoint_visible = false; 1570 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1571 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1572 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1573 // the exception consists of creating the exception object & initializing it, initialization 1574 // will leave the VM via a JavaCall and then all locks must be unlocked). 1575 // 1576 // The thread is still suspended when we reach here. Thread must be explicit started 1577 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1578 // by calling Threads:add. The reason why this is not done here, is because the thread 1579 // object must be fully initialized (take a look at JVM_Start) 1580 } 1581 1582 JavaThread::~JavaThread() { 1583 if (TraceThreadEvents) { 1584 tty->print_cr("terminate thread %p", this); 1585 } 1586 1587 // By now, this thread should already be invisible to safepoint, 1588 // and its per-thread recorder also collected. 1589 assert(!is_safepoint_visible(), "wrong state"); 1590 #if INCLUDE_NMT 1591 assert(get_recorder() == NULL, "Already collected"); 1592 #endif // INCLUDE_NMT 1593 1594 // JSR166 -- return the parker to the free list 1595 Parker::Release(_parker); 1596 _parker = NULL ; 1597 1598 // Free any remaining previous UnrollBlock 1599 vframeArray* old_array = vframe_array_last(); 1600 1601 if (old_array != NULL) { 1602 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1603 old_array->set_unroll_block(NULL); 1604 delete old_info; 1605 delete old_array; 1606 } 1607 1608 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1609 if (deferred != NULL) { 1610 // This can only happen if thread is destroyed before deoptimization occurs. 1611 assert(deferred->length() != 0, "empty array!"); 1612 do { 1613 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1614 deferred->remove_at(0); 1615 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1616 delete dlv; 1617 } while (deferred->length() != 0); 1618 delete deferred; 1619 } 1620 1621 // All Java related clean up happens in exit 1622 ThreadSafepointState::destroy(this); 1623 if (_thread_profiler != NULL) delete _thread_profiler; 1624 if (_thread_stat != NULL) delete _thread_stat; 1625 } 1626 1627 1628 // The first routine called by a new Java thread 1629 void JavaThread::run() { 1630 // initialize thread-local alloc buffer related fields 1631 this->initialize_tlab(); 1632 1633 // used to test validitity of stack trace backs 1634 this->record_base_of_stack_pointer(); 1635 1636 // Record real stack base and size. 1637 this->record_stack_base_and_size(); 1638 1639 // Initialize thread local storage; set before calling MutexLocker 1640 this->initialize_thread_local_storage(); 1641 1642 this->create_stack_guard_pages(); 1643 1644 this->cache_global_variables(); 1645 1646 // Thread is now sufficient initialized to be handled by the safepoint code as being 1647 // in the VM. Change thread state from _thread_new to _thread_in_vm 1648 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1649 1650 assert(JavaThread::current() == this, "sanity check"); 1651 assert(!Thread::current()->owns_locks(), "sanity check"); 1652 1653 DTRACE_THREAD_PROBE(start, this); 1654 1655 // This operation might block. We call that after all safepoint checks for a new thread has 1656 // been completed. 1657 this->set_active_handles(JNIHandleBlock::allocate_block()); 1658 1659 if (JvmtiExport::should_post_thread_life()) { 1660 JvmtiExport::post_thread_start(this); 1661 } 1662 1663 EVENT_BEGIN(TraceEventThreadStart, event); 1664 EVENT_COMMIT(event, 1665 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj()))); 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 EVENT_BEGIN(TraceEventThreadEnd, event); 1796 EVENT_COMMIT(event, 1797 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj()))); 1798 1799 // Call after last event on thread 1800 EVENT_THREAD_EXIT(this); 1801 1802 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1803 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1804 // is deprecated anyhow. 1805 { int count = 3; 1806 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1807 EXCEPTION_MARK; 1808 JavaValue result(T_VOID); 1809 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1810 JavaCalls::call_virtual(&result, 1811 threadObj, thread_klass, 1812 vmSymbols::exit_method_name(), 1813 vmSymbols::void_method_signature(), 1814 THREAD); 1815 CLEAR_PENDING_EXCEPTION; 1816 } 1817 } 1818 1819 // notify JVMTI 1820 if (JvmtiExport::should_post_thread_life()) { 1821 JvmtiExport::post_thread_end(this); 1822 } 1823 1824 // We have notified the agents that we are exiting, before we go on, 1825 // we must check for a pending external suspend request and honor it 1826 // in order to not surprise the thread that made the suspend request. 1827 while (true) { 1828 { 1829 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1830 if (!is_external_suspend()) { 1831 set_terminated(_thread_exiting); 1832 ThreadService::current_thread_exiting(this); 1833 break; 1834 } 1835 // Implied else: 1836 // Things get a little tricky here. We have a pending external 1837 // suspend request, but we are holding the SR_lock so we 1838 // can't just self-suspend. So we temporarily drop the lock 1839 // and then self-suspend. 1840 } 1841 1842 ThreadBlockInVM tbivm(this); 1843 java_suspend_self(); 1844 1845 // We're done with this suspend request, but we have to loop around 1846 // and check again. Eventually we will get SR_lock without a pending 1847 // external suspend request and will be able to mark ourselves as 1848 // exiting. 1849 } 1850 // no more external suspends are allowed at this point 1851 } else { 1852 // before_exit() has already posted JVMTI THREAD_END events 1853 } 1854 1855 // Notify waiters on thread object. This has to be done after exit() is called 1856 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1857 // group should have the destroyed bit set before waiters are notified). 1858 ensure_join(this); 1859 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1860 1861 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1862 // held by this thread must be released. A detach operation must only 1863 // get here if there are no Java frames on the stack. Therefore, any 1864 // owned monitors at this point MUST be JNI-acquired monitors which are 1865 // pre-inflated and in the monitor cache. 1866 // 1867 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1868 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1869 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1870 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1871 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1872 } 1873 1874 // These things needs to be done while we are still a Java Thread. Make sure that thread 1875 // is in a consistent state, in case GC happens 1876 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1877 1878 if (active_handles() != NULL) { 1879 JNIHandleBlock* block = active_handles(); 1880 set_active_handles(NULL); 1881 JNIHandleBlock::release_block(block); 1882 } 1883 1884 if (free_handle_block() != NULL) { 1885 JNIHandleBlock* block = free_handle_block(); 1886 set_free_handle_block(NULL); 1887 JNIHandleBlock::release_block(block); 1888 } 1889 1890 // These have to be removed while this is still a valid thread. 1891 remove_stack_guard_pages(); 1892 1893 if (UseTLAB) { 1894 tlab().make_parsable(true); // retire TLAB 1895 } 1896 1897 if (JvmtiEnv::environments_might_exist()) { 1898 JvmtiExport::cleanup_thread(this); 1899 } 1900 1901 // We must flush any deferred card marks before removing a thread from 1902 // the list of active threads. 1903 Universe::heap()->flush_deferred_store_barrier(this); 1904 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1905 1906 #if INCLUDE_ALL_GCS 1907 // We must flush the G1-related buffers before removing a thread 1908 // from the list of active threads. We must do this after any deferred 1909 // card marks have been flushed (above) so that any entries that are 1910 // added to the thread's dirty card queue as a result are not lost. 1911 if (UseG1GC) { 1912 flush_barrier_queues(); 1913 } 1914 #endif // INCLUDE_ALL_GCS 1915 1916 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1917 Threads::remove(this); 1918 } 1919 1920 #if INCLUDE_ALL_GCS 1921 // Flush G1-related queues. 1922 void JavaThread::flush_barrier_queues() { 1923 satb_mark_queue().flush(); 1924 dirty_card_queue().flush(); 1925 } 1926 1927 void JavaThread::initialize_queues() { 1928 assert(!SafepointSynchronize::is_at_safepoint(), 1929 "we should not be at a safepoint"); 1930 1931 ObjPtrQueue& satb_queue = satb_mark_queue(); 1932 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1933 // The SATB queue should have been constructed with its active 1934 // field set to false. 1935 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1936 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1937 // If we are creating the thread during a marking cycle, we should 1938 // set the active field of the SATB queue to true. 1939 if (satb_queue_set.is_active()) { 1940 satb_queue.set_active(true); 1941 } 1942 1943 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1944 // The dirty card queue should have been constructed with its 1945 // active field set to true. 1946 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1947 } 1948 #endif // INCLUDE_ALL_GCS 1949 1950 void JavaThread::cleanup_failed_attach_current_thread() { 1951 if (get_thread_profiler() != NULL) { 1952 get_thread_profiler()->disengage(); 1953 ResourceMark rm; 1954 get_thread_profiler()->print(get_thread_name()); 1955 } 1956 1957 if (active_handles() != NULL) { 1958 JNIHandleBlock* block = active_handles(); 1959 set_active_handles(NULL); 1960 JNIHandleBlock::release_block(block); 1961 } 1962 1963 if (free_handle_block() != NULL) { 1964 JNIHandleBlock* block = free_handle_block(); 1965 set_free_handle_block(NULL); 1966 JNIHandleBlock::release_block(block); 1967 } 1968 1969 // These have to be removed while this is still a valid thread. 1970 remove_stack_guard_pages(); 1971 1972 if (UseTLAB) { 1973 tlab().make_parsable(true); // retire TLAB, if any 1974 } 1975 1976 #if INCLUDE_ALL_GCS 1977 if (UseG1GC) { 1978 flush_barrier_queues(); 1979 } 1980 #endif // INCLUDE_ALL_GCS 1981 1982 Threads::remove(this); 1983 delete this; 1984 } 1985 1986 1987 1988 1989 JavaThread* JavaThread::active() { 1990 Thread* thread = ThreadLocalStorage::thread(); 1991 assert(thread != NULL, "just checking"); 1992 if (thread->is_Java_thread()) { 1993 return (JavaThread*) thread; 1994 } else { 1995 assert(thread->is_VM_thread(), "this must be a vm thread"); 1996 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1997 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1998 assert(ret->is_Java_thread(), "must be a Java thread"); 1999 return ret; 2000 } 2001 } 2002 2003 bool JavaThread::is_lock_owned(address adr) const { 2004 if (Thread::is_lock_owned(adr)) return true; 2005 2006 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2007 if (chunk->contains(adr)) return true; 2008 } 2009 2010 return false; 2011 } 2012 2013 2014 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2015 chunk->set_next(monitor_chunks()); 2016 set_monitor_chunks(chunk); 2017 } 2018 2019 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2020 guarantee(monitor_chunks() != NULL, "must be non empty"); 2021 if (monitor_chunks() == chunk) { 2022 set_monitor_chunks(chunk->next()); 2023 } else { 2024 MonitorChunk* prev = monitor_chunks(); 2025 while (prev->next() != chunk) prev = prev->next(); 2026 prev->set_next(chunk->next()); 2027 } 2028 } 2029 2030 // JVM support. 2031 2032 // Note: this function shouldn't block if it's called in 2033 // _thread_in_native_trans state (such as from 2034 // check_special_condition_for_native_trans()). 2035 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2036 2037 if (has_last_Java_frame() && has_async_condition()) { 2038 // If we are at a polling page safepoint (not a poll return) 2039 // then we must defer async exception because live registers 2040 // will be clobbered by the exception path. Poll return is 2041 // ok because the call we a returning from already collides 2042 // with exception handling registers and so there is no issue. 2043 // (The exception handling path kills call result registers but 2044 // this is ok since the exception kills the result anyway). 2045 2046 if (is_at_poll_safepoint()) { 2047 // if the code we are returning to has deoptimized we must defer 2048 // the exception otherwise live registers get clobbered on the 2049 // exception path before deoptimization is able to retrieve them. 2050 // 2051 RegisterMap map(this, false); 2052 frame caller_fr = last_frame().sender(&map); 2053 assert(caller_fr.is_compiled_frame(), "what?"); 2054 if (caller_fr.is_deoptimized_frame()) { 2055 if (TraceExceptions) { 2056 ResourceMark rm; 2057 tty->print_cr("deferred async exception at compiled safepoint"); 2058 } 2059 return; 2060 } 2061 } 2062 } 2063 2064 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2065 if (condition == _no_async_condition) { 2066 // Conditions have changed since has_special_runtime_exit_condition() 2067 // was called: 2068 // - if we were here only because of an external suspend request, 2069 // then that was taken care of above (or cancelled) so we are done 2070 // - if we were here because of another async request, then it has 2071 // been cleared between the has_special_runtime_exit_condition() 2072 // and now so again we are done 2073 return; 2074 } 2075 2076 // Check for pending async. exception 2077 if (_pending_async_exception != NULL) { 2078 // Only overwrite an already pending exception, if it is not a threadDeath. 2079 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2080 2081 // We cannot call Exceptions::_throw(...) here because we cannot block 2082 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2083 2084 if (TraceExceptions) { 2085 ResourceMark rm; 2086 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2087 if (has_last_Java_frame() ) { 2088 frame f = last_frame(); 2089 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2090 } 2091 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2092 } 2093 _pending_async_exception = NULL; 2094 clear_has_async_exception(); 2095 } 2096 } 2097 2098 if (check_unsafe_error && 2099 condition == _async_unsafe_access_error && !has_pending_exception()) { 2100 condition = _no_async_condition; // done 2101 switch (thread_state()) { 2102 case _thread_in_vm: 2103 { 2104 JavaThread* THREAD = this; 2105 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2106 } 2107 case _thread_in_native: 2108 { 2109 ThreadInVMfromNative tiv(this); 2110 JavaThread* THREAD = this; 2111 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2112 } 2113 case _thread_in_Java: 2114 { 2115 ThreadInVMfromJava tiv(this); 2116 JavaThread* THREAD = this; 2117 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2118 } 2119 default: 2120 ShouldNotReachHere(); 2121 } 2122 } 2123 2124 assert(condition == _no_async_condition || has_pending_exception() || 2125 (!check_unsafe_error && condition == _async_unsafe_access_error), 2126 "must have handled the async condition, if no exception"); 2127 } 2128 2129 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2130 // 2131 // Check for pending external suspend. Internal suspend requests do 2132 // not use handle_special_runtime_exit_condition(). 2133 // If JNIEnv proxies are allowed, don't self-suspend if the target 2134 // thread is not the current thread. In older versions of jdbx, jdbx 2135 // threads could call into the VM with another thread's JNIEnv so we 2136 // can be here operating on behalf of a suspended thread (4432884). 2137 bool do_self_suspend = is_external_suspend_with_lock(); 2138 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2139 // 2140 // Because thread is external suspended the safepoint code will count 2141 // thread as at a safepoint. This can be odd because we can be here 2142 // as _thread_in_Java which would normally transition to _thread_blocked 2143 // at a safepoint. We would like to mark the thread as _thread_blocked 2144 // before calling java_suspend_self like all other callers of it but 2145 // we must then observe proper safepoint protocol. (We can't leave 2146 // _thread_blocked with a safepoint in progress). However we can be 2147 // here as _thread_in_native_trans so we can't use a normal transition 2148 // constructor/destructor pair because they assert on that type of 2149 // transition. We could do something like: 2150 // 2151 // JavaThreadState state = thread_state(); 2152 // set_thread_state(_thread_in_vm); 2153 // { 2154 // ThreadBlockInVM tbivm(this); 2155 // java_suspend_self() 2156 // } 2157 // set_thread_state(_thread_in_vm_trans); 2158 // if (safepoint) block; 2159 // set_thread_state(state); 2160 // 2161 // but that is pretty messy. Instead we just go with the way the 2162 // code has worked before and note that this is the only path to 2163 // java_suspend_self that doesn't put the thread in _thread_blocked 2164 // mode. 2165 2166 frame_anchor()->make_walkable(this); 2167 java_suspend_self(); 2168 2169 // We might be here for reasons in addition to the self-suspend request 2170 // so check for other async requests. 2171 } 2172 2173 if (check_asyncs) { 2174 check_and_handle_async_exceptions(); 2175 } 2176 } 2177 2178 void JavaThread::send_thread_stop(oop java_throwable) { 2179 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2180 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2181 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2182 2183 // Do not throw asynchronous exceptions against the compiler thread 2184 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2185 if (is_Compiler_thread()) return; 2186 2187 { 2188 // Actually throw the Throwable against the target Thread - however 2189 // only if there is no thread death exception installed already. 2190 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2191 // If the topmost frame is a runtime stub, then we are calling into 2192 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2193 // must deoptimize the caller before continuing, as the compiled exception handler table 2194 // may not be valid 2195 if (has_last_Java_frame()) { 2196 frame f = last_frame(); 2197 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2198 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2199 RegisterMap reg_map(this, UseBiasedLocking); 2200 frame compiled_frame = f.sender(®_map); 2201 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2202 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2203 } 2204 } 2205 } 2206 2207 // Set async. pending exception in thread. 2208 set_pending_async_exception(java_throwable); 2209 2210 if (TraceExceptions) { 2211 ResourceMark rm; 2212 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2213 } 2214 // for AbortVMOnException flag 2215 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2216 } 2217 } 2218 2219 2220 // Interrupt thread so it will wake up from a potential wait() 2221 Thread::interrupt(this); 2222 } 2223 2224 // External suspension mechanism. 2225 // 2226 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2227 // to any VM_locks and it is at a transition 2228 // Self-suspension will happen on the transition out of the vm. 2229 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2230 // 2231 // Guarantees on return: 2232 // + Target thread will not execute any new bytecode (that's why we need to 2233 // force a safepoint) 2234 // + Target thread will not enter any new monitors 2235 // 2236 void JavaThread::java_suspend() { 2237 { MutexLocker mu(Threads_lock); 2238 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2239 return; 2240 } 2241 } 2242 2243 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2244 if (!is_external_suspend()) { 2245 // a racing resume has cancelled us; bail out now 2246 return; 2247 } 2248 2249 // suspend is done 2250 uint32_t debug_bits = 0; 2251 // Warning: is_ext_suspend_completed() may temporarily drop the 2252 // SR_lock to allow the thread to reach a stable thread state if 2253 // it is currently in a transient thread state. 2254 if (is_ext_suspend_completed(false /* !called_by_wait */, 2255 SuspendRetryDelay, &debug_bits) ) { 2256 return; 2257 } 2258 } 2259 2260 VM_ForceSafepoint vm_suspend; 2261 VMThread::execute(&vm_suspend); 2262 } 2263 2264 // Part II of external suspension. 2265 // A JavaThread self suspends when it detects a pending external suspend 2266 // request. This is usually on transitions. It is also done in places 2267 // where continuing to the next transition would surprise the caller, 2268 // e.g., monitor entry. 2269 // 2270 // Returns the number of times that the thread self-suspended. 2271 // 2272 // Note: DO NOT call java_suspend_self() when you just want to block current 2273 // thread. java_suspend_self() is the second stage of cooperative 2274 // suspension for external suspend requests and should only be used 2275 // to complete an external suspend request. 2276 // 2277 int JavaThread::java_suspend_self() { 2278 int ret = 0; 2279 2280 // we are in the process of exiting so don't suspend 2281 if (is_exiting()) { 2282 clear_external_suspend(); 2283 return ret; 2284 } 2285 2286 assert(_anchor.walkable() || 2287 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2288 "must have walkable stack"); 2289 2290 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2291 2292 assert(!this->is_ext_suspended(), 2293 "a thread trying to self-suspend should not already be suspended"); 2294 2295 if (this->is_suspend_equivalent()) { 2296 // If we are self-suspending as a result of the lifting of a 2297 // suspend equivalent condition, then the suspend_equivalent 2298 // flag is not cleared until we set the ext_suspended flag so 2299 // that wait_for_ext_suspend_completion() returns consistent 2300 // results. 2301 this->clear_suspend_equivalent(); 2302 } 2303 2304 // A racing resume may have cancelled us before we grabbed SR_lock 2305 // above. Or another external suspend request could be waiting for us 2306 // by the time we return from SR_lock()->wait(). The thread 2307 // that requested the suspension may already be trying to walk our 2308 // stack and if we return now, we can change the stack out from under 2309 // it. This would be a "bad thing (TM)" and cause the stack walker 2310 // to crash. We stay self-suspended until there are no more pending 2311 // external suspend requests. 2312 while (is_external_suspend()) { 2313 ret++; 2314 this->set_ext_suspended(); 2315 2316 // _ext_suspended flag is cleared by java_resume() 2317 while (is_ext_suspended()) { 2318 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2319 } 2320 } 2321 2322 return ret; 2323 } 2324 2325 #ifdef ASSERT 2326 // verify the JavaThread has not yet been published in the Threads::list, and 2327 // hence doesn't need protection from concurrent access at this stage 2328 void JavaThread::verify_not_published() { 2329 if (!Threads_lock->owned_by_self()) { 2330 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2331 assert( !Threads::includes(this), 2332 "java thread shouldn't have been published yet!"); 2333 } 2334 else { 2335 assert( !Threads::includes(this), 2336 "java thread shouldn't have been published yet!"); 2337 } 2338 } 2339 #endif 2340 2341 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2342 // progress or when _suspend_flags is non-zero. 2343 // Current thread needs to self-suspend if there is a suspend request and/or 2344 // block if a safepoint is in progress. 2345 // Async exception ISN'T checked. 2346 // Note only the ThreadInVMfromNative transition can call this function 2347 // directly and when thread state is _thread_in_native_trans 2348 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2349 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2350 2351 JavaThread *curJT = JavaThread::current(); 2352 bool do_self_suspend = thread->is_external_suspend(); 2353 2354 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2355 2356 // If JNIEnv proxies are allowed, don't self-suspend if the target 2357 // thread is not the current thread. In older versions of jdbx, jdbx 2358 // threads could call into the VM with another thread's JNIEnv so we 2359 // can be here operating on behalf of a suspended thread (4432884). 2360 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2361 JavaThreadState state = thread->thread_state(); 2362 2363 // We mark this thread_blocked state as a suspend-equivalent so 2364 // that a caller to is_ext_suspend_completed() won't be confused. 2365 // The suspend-equivalent state is cleared by java_suspend_self(). 2366 thread->set_suspend_equivalent(); 2367 2368 // If the safepoint code sees the _thread_in_native_trans state, it will 2369 // wait until the thread changes to other thread state. There is no 2370 // guarantee on how soon we can obtain the SR_lock and complete the 2371 // self-suspend request. It would be a bad idea to let safepoint wait for 2372 // too long. Temporarily change the state to _thread_blocked to 2373 // let the VM thread know that this thread is ready for GC. The problem 2374 // of changing thread state is that safepoint could happen just after 2375 // java_suspend_self() returns after being resumed, and VM thread will 2376 // see the _thread_blocked state. We must check for safepoint 2377 // after restoring the state and make sure we won't leave while a safepoint 2378 // is in progress. 2379 thread->set_thread_state(_thread_blocked); 2380 thread->java_suspend_self(); 2381 thread->set_thread_state(state); 2382 // Make sure new state is seen by VM thread 2383 if (os::is_MP()) { 2384 if (UseMembar) { 2385 // Force a fence between the write above and read below 2386 OrderAccess::fence(); 2387 } else { 2388 // Must use this rather than serialization page in particular on Windows 2389 InterfaceSupport::serialize_memory(thread); 2390 } 2391 } 2392 } 2393 2394 if (SafepointSynchronize::do_call_back()) { 2395 // If we are safepointing, then block the caller which may not be 2396 // the same as the target thread (see above). 2397 SafepointSynchronize::block(curJT); 2398 } 2399 2400 if (thread->is_deopt_suspend()) { 2401 thread->clear_deopt_suspend(); 2402 RegisterMap map(thread, false); 2403 frame f = thread->last_frame(); 2404 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2405 f = f.sender(&map); 2406 } 2407 if (f.id() == thread->must_deopt_id()) { 2408 thread->clear_must_deopt_id(); 2409 f.deoptimize(thread); 2410 } else { 2411 fatal("missed deoptimization!"); 2412 } 2413 } 2414 } 2415 2416 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2417 // progress or when _suspend_flags is non-zero. 2418 // Current thread needs to self-suspend if there is a suspend request and/or 2419 // block if a safepoint is in progress. 2420 // Also check for pending async exception (not including unsafe access error). 2421 // Note only the native==>VM/Java barriers can call this function and when 2422 // thread state is _thread_in_native_trans. 2423 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2424 check_safepoint_and_suspend_for_native_trans(thread); 2425 2426 if (thread->has_async_exception()) { 2427 // We are in _thread_in_native_trans state, don't handle unsafe 2428 // access error since that may block. 2429 thread->check_and_handle_async_exceptions(false); 2430 } 2431 } 2432 2433 // This is a variant of the normal 2434 // check_special_condition_for_native_trans with slightly different 2435 // semantics for use by critical native wrappers. It does all the 2436 // normal checks but also performs the transition back into 2437 // thread_in_Java state. This is required so that critical natives 2438 // can potentially block and perform a GC if they are the last thread 2439 // exiting the GC_locker. 2440 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2441 check_special_condition_for_native_trans(thread); 2442 2443 // Finish the transition 2444 thread->set_thread_state(_thread_in_Java); 2445 2446 if (thread->do_critical_native_unlock()) { 2447 ThreadInVMfromJavaNoAsyncException tiv(thread); 2448 GC_locker::unlock_critical(thread); 2449 thread->clear_critical_native_unlock(); 2450 } 2451 } 2452 2453 // We need to guarantee the Threads_lock here, since resumes are not 2454 // allowed during safepoint synchronization 2455 // Can only resume from an external suspension 2456 void JavaThread::java_resume() { 2457 assert_locked_or_safepoint(Threads_lock); 2458 2459 // Sanity check: thread is gone, has started exiting or the thread 2460 // was not externally suspended. 2461 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2462 return; 2463 } 2464 2465 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2466 2467 clear_external_suspend(); 2468 2469 if (is_ext_suspended()) { 2470 clear_ext_suspended(); 2471 SR_lock()->notify_all(); 2472 } 2473 } 2474 2475 void JavaThread::create_stack_guard_pages() { 2476 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2477 address low_addr = stack_base() - stack_size(); 2478 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2479 2480 int allocate = os::allocate_stack_guard_pages(); 2481 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2482 2483 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2484 warning("Attempt to allocate stack guard pages failed."); 2485 return; 2486 } 2487 2488 if (os::guard_memory((char *) low_addr, len)) { 2489 _stack_guard_state = stack_guard_enabled; 2490 } else { 2491 warning("Attempt to protect stack guard pages failed."); 2492 if (os::uncommit_memory((char *) low_addr, len)) { 2493 warning("Attempt to deallocate stack guard pages failed."); 2494 } 2495 } 2496 } 2497 2498 void JavaThread::remove_stack_guard_pages() { 2499 assert(Thread::current() == this, "from different thread"); 2500 if (_stack_guard_state == stack_guard_unused) return; 2501 address low_addr = stack_base() - stack_size(); 2502 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2503 2504 if (os::allocate_stack_guard_pages()) { 2505 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2506 _stack_guard_state = stack_guard_unused; 2507 } else { 2508 warning("Attempt to deallocate stack guard pages failed."); 2509 } 2510 } else { 2511 if (_stack_guard_state == stack_guard_unused) return; 2512 if (os::unguard_memory((char *) low_addr, len)) { 2513 _stack_guard_state = stack_guard_unused; 2514 } else { 2515 warning("Attempt to unprotect stack guard pages failed."); 2516 } 2517 } 2518 } 2519 2520 void JavaThread::enable_stack_yellow_zone() { 2521 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2522 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2523 2524 // The base notation is from the stacks point of view, growing downward. 2525 // We need to adjust it to work correctly with guard_memory() 2526 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2527 2528 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2529 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2530 2531 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2532 _stack_guard_state = stack_guard_enabled; 2533 } else { 2534 warning("Attempt to guard stack yellow zone failed."); 2535 } 2536 enable_register_stack_guard(); 2537 } 2538 2539 void JavaThread::disable_stack_yellow_zone() { 2540 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2541 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2542 2543 // Simply return if called for a thread that does not use guard pages. 2544 if (_stack_guard_state == stack_guard_unused) return; 2545 2546 // The base notation is from the stacks point of view, growing downward. 2547 // We need to adjust it to work correctly with guard_memory() 2548 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2549 2550 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2551 _stack_guard_state = stack_guard_yellow_disabled; 2552 } else { 2553 warning("Attempt to unguard stack yellow zone failed."); 2554 } 2555 disable_register_stack_guard(); 2556 } 2557 2558 void JavaThread::enable_stack_red_zone() { 2559 // The base notation is from the stacks point of view, growing downward. 2560 // We need to adjust it to work correctly with guard_memory() 2561 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2562 address base = stack_red_zone_base() - stack_red_zone_size(); 2563 2564 guarantee(base < stack_base(),"Error calculating stack red zone"); 2565 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2566 2567 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2568 warning("Attempt to guard stack red zone failed."); 2569 } 2570 } 2571 2572 void JavaThread::disable_stack_red_zone() { 2573 // The base notation is from the stacks point of view, growing downward. 2574 // We need to adjust it to work correctly with guard_memory() 2575 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2576 address base = stack_red_zone_base() - stack_red_zone_size(); 2577 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2578 warning("Attempt to unguard stack red zone failed."); 2579 } 2580 } 2581 2582 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2583 // ignore is there is no stack 2584 if (!has_last_Java_frame()) return; 2585 // traverse the stack frames. Starts from top frame. 2586 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2587 frame* fr = fst.current(); 2588 f(fr, fst.register_map()); 2589 } 2590 } 2591 2592 2593 #ifndef PRODUCT 2594 // Deoptimization 2595 // Function for testing deoptimization 2596 void JavaThread::deoptimize() { 2597 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2598 StackFrameStream fst(this, UseBiasedLocking); 2599 bool deopt = false; // Dump stack only if a deopt actually happens. 2600 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2601 // Iterate over all frames in the thread and deoptimize 2602 for(; !fst.is_done(); fst.next()) { 2603 if(fst.current()->can_be_deoptimized()) { 2604 2605 if (only_at) { 2606 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2607 // consists of comma or carriage return separated numbers so 2608 // search for the current bci in that string. 2609 address pc = fst.current()->pc(); 2610 nmethod* nm = (nmethod*) fst.current()->cb(); 2611 ScopeDesc* sd = nm->scope_desc_at( pc); 2612 char buffer[8]; 2613 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2614 size_t len = strlen(buffer); 2615 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2616 while (found != NULL) { 2617 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2618 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2619 // Check that the bci found is bracketed by terminators. 2620 break; 2621 } 2622 found = strstr(found + 1, buffer); 2623 } 2624 if (!found) { 2625 continue; 2626 } 2627 } 2628 2629 if (DebugDeoptimization && !deopt) { 2630 deopt = true; // One-time only print before deopt 2631 tty->print_cr("[BEFORE Deoptimization]"); 2632 trace_frames(); 2633 trace_stack(); 2634 } 2635 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2636 } 2637 } 2638 2639 if (DebugDeoptimization && deopt) { 2640 tty->print_cr("[AFTER Deoptimization]"); 2641 trace_frames(); 2642 } 2643 } 2644 2645 2646 // Make zombies 2647 void JavaThread::make_zombies() { 2648 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2649 if (fst.current()->can_be_deoptimized()) { 2650 // it is a Java nmethod 2651 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2652 nm->make_not_entrant(); 2653 } 2654 } 2655 } 2656 #endif // PRODUCT 2657 2658 2659 void JavaThread::deoptimized_wrt_marked_nmethods() { 2660 if (!has_last_Java_frame()) return; 2661 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2662 StackFrameStream fst(this, UseBiasedLocking); 2663 for(; !fst.is_done(); fst.next()) { 2664 if (fst.current()->should_be_deoptimized()) { 2665 if (LogCompilation && xtty != NULL) { 2666 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2667 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2668 this->name(), nm != NULL ? nm->compile_id() : -1); 2669 } 2670 2671 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2672 } 2673 } 2674 } 2675 2676 2677 // GC support 2678 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2679 2680 void JavaThread::gc_epilogue() { 2681 frames_do(frame_gc_epilogue); 2682 } 2683 2684 2685 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2686 2687 void JavaThread::gc_prologue() { 2688 frames_do(frame_gc_prologue); 2689 } 2690 2691 // If the caller is a NamedThread, then remember, in the current scope, 2692 // the given JavaThread in its _processed_thread field. 2693 class RememberProcessedThread: public StackObj { 2694 NamedThread* _cur_thr; 2695 public: 2696 RememberProcessedThread(JavaThread* jthr) { 2697 Thread* thread = Thread::current(); 2698 if (thread->is_Named_thread()) { 2699 _cur_thr = (NamedThread *)thread; 2700 _cur_thr->set_processed_thread(jthr); 2701 } else { 2702 _cur_thr = NULL; 2703 } 2704 } 2705 2706 ~RememberProcessedThread() { 2707 if (_cur_thr) { 2708 _cur_thr->set_processed_thread(NULL); 2709 } 2710 } 2711 }; 2712 2713 void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 2714 // Verify that the deferred card marks have been flushed. 2715 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2716 2717 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2718 // since there may be more than one thread using each ThreadProfiler. 2719 2720 // Traverse the GCHandles 2721 Thread::oops_do(f, cld_f, cf); 2722 2723 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2724 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2725 2726 if (has_last_Java_frame()) { 2727 // Record JavaThread to GC thread 2728 RememberProcessedThread rpt(this); 2729 2730 // Traverse the privileged stack 2731 if (_privileged_stack_top != NULL) { 2732 _privileged_stack_top->oops_do(f); 2733 } 2734 2735 // traverse the registered growable array 2736 if (_array_for_gc != NULL) { 2737 for (int index = 0; index < _array_for_gc->length(); index++) { 2738 f->do_oop(_array_for_gc->adr_at(index)); 2739 } 2740 } 2741 2742 // Traverse the monitor chunks 2743 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2744 chunk->oops_do(f); 2745 } 2746 2747 // Traverse the execution stack 2748 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2749 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2750 } 2751 } 2752 2753 // callee_target is never live across a gc point so NULL it here should 2754 // it still contain a methdOop. 2755 2756 set_callee_target(NULL); 2757 2758 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2759 // If we have deferred set_locals there might be oops waiting to be 2760 // written 2761 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2762 if (list != NULL) { 2763 for (int i = 0; i < list->length(); i++) { 2764 list->at(i)->oops_do(f); 2765 } 2766 } 2767 2768 // Traverse instance variables at the end since the GC may be moving things 2769 // around using this function 2770 f->do_oop((oop*) &_threadObj); 2771 f->do_oop((oop*) &_vm_result); 2772 f->do_oop((oop*) &_exception_oop); 2773 f->do_oop((oop*) &_pending_async_exception); 2774 2775 if (jvmti_thread_state() != NULL) { 2776 jvmti_thread_state()->oops_do(f); 2777 } 2778 } 2779 2780 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2781 Thread::nmethods_do(cf); // (super method is a no-op) 2782 2783 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2784 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2785 2786 if (has_last_Java_frame()) { 2787 // Traverse the execution stack 2788 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2789 fst.current()->nmethods_do(cf); 2790 } 2791 } 2792 } 2793 2794 void JavaThread::metadata_do(void f(Metadata*)) { 2795 Thread::metadata_do(f); 2796 if (has_last_Java_frame()) { 2797 // Traverse the execution stack to call f() on the methods in the stack 2798 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2799 fst.current()->metadata_do(f); 2800 } 2801 } else if (is_Compiler_thread()) { 2802 // need to walk ciMetadata in current compile tasks to keep alive. 2803 CompilerThread* ct = (CompilerThread*)this; 2804 if (ct->env() != NULL) { 2805 ct->env()->metadata_do(f); 2806 } 2807 } 2808 } 2809 2810 // Printing 2811 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2812 switch (_thread_state) { 2813 case _thread_uninitialized: return "_thread_uninitialized"; 2814 case _thread_new: return "_thread_new"; 2815 case _thread_new_trans: return "_thread_new_trans"; 2816 case _thread_in_native: return "_thread_in_native"; 2817 case _thread_in_native_trans: return "_thread_in_native_trans"; 2818 case _thread_in_vm: return "_thread_in_vm"; 2819 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2820 case _thread_in_Java: return "_thread_in_Java"; 2821 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2822 case _thread_blocked: return "_thread_blocked"; 2823 case _thread_blocked_trans: return "_thread_blocked_trans"; 2824 default: return "unknown thread state"; 2825 } 2826 } 2827 2828 #ifndef PRODUCT 2829 void JavaThread::print_thread_state_on(outputStream *st) const { 2830 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2831 }; 2832 void JavaThread::print_thread_state() const { 2833 print_thread_state_on(tty); 2834 }; 2835 #endif // PRODUCT 2836 2837 // Called by Threads::print() for VM_PrintThreads operation 2838 void JavaThread::print_on(outputStream *st) const { 2839 st->print("\"%s\" ", get_thread_name()); 2840 oop thread_oop = threadObj(); 2841 if (thread_oop != NULL) { 2842 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2843 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2844 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2845 } 2846 Thread::print_on(st); 2847 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2848 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2849 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2850 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2851 } 2852 #ifndef PRODUCT 2853 print_thread_state_on(st); 2854 _safepoint_state->print_on(st); 2855 #endif // PRODUCT 2856 } 2857 2858 // Called by fatal error handler. The difference between this and 2859 // JavaThread::print() is that we can't grab lock or allocate memory. 2860 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2861 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2862 oop thread_obj = threadObj(); 2863 if (thread_obj != NULL) { 2864 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2865 } 2866 st->print(" ["); 2867 st->print("%s", _get_thread_state_name(_thread_state)); 2868 if (osthread()) { 2869 st->print(", id=%d", osthread()->thread_id()); 2870 } 2871 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2872 _stack_base - _stack_size, _stack_base); 2873 st->print("]"); 2874 return; 2875 } 2876 2877 // Verification 2878 2879 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2880 2881 void JavaThread::verify() { 2882 // Verify oops in the thread. 2883 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2884 2885 // Verify the stack frames. 2886 frames_do(frame_verify); 2887 } 2888 2889 // CR 6300358 (sub-CR 2137150) 2890 // Most callers of this method assume that it can't return NULL but a 2891 // thread may not have a name whilst it is in the process of attaching to 2892 // the VM - see CR 6412693, and there are places where a JavaThread can be 2893 // seen prior to having it's threadObj set (eg JNI attaching threads and 2894 // if vm exit occurs during initialization). These cases can all be accounted 2895 // for such that this method never returns NULL. 2896 const char* JavaThread::get_thread_name() const { 2897 #ifdef ASSERT 2898 // early safepoints can hit while current thread does not yet have TLS 2899 if (!SafepointSynchronize::is_at_safepoint()) { 2900 Thread *cur = Thread::current(); 2901 if (!(cur->is_Java_thread() && cur == this)) { 2902 // Current JavaThreads are allowed to get their own name without 2903 // the Threads_lock. 2904 assert_locked_or_safepoint(Threads_lock); 2905 } 2906 } 2907 #endif // ASSERT 2908 return get_thread_name_string(); 2909 } 2910 2911 // Returns a non-NULL representation of this thread's name, or a suitable 2912 // descriptive string if there is no set name 2913 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2914 const char* name_str; 2915 oop thread_obj = threadObj(); 2916 if (thread_obj != NULL) { 2917 typeArrayOop name = java_lang_Thread::name(thread_obj); 2918 if (name != NULL) { 2919 if (buf == NULL) { 2920 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2921 } 2922 else { 2923 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2924 } 2925 } 2926 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2927 name_str = "<no-name - thread is attaching>"; 2928 } 2929 else { 2930 name_str = Thread::name(); 2931 } 2932 } 2933 else { 2934 name_str = Thread::name(); 2935 } 2936 assert(name_str != NULL, "unexpected NULL thread name"); 2937 return name_str; 2938 } 2939 2940 2941 const char* JavaThread::get_threadgroup_name() const { 2942 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2943 oop thread_obj = threadObj(); 2944 if (thread_obj != NULL) { 2945 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2946 if (thread_group != NULL) { 2947 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2948 // ThreadGroup.name can be null 2949 if (name != NULL) { 2950 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2951 return str; 2952 } 2953 } 2954 } 2955 return NULL; 2956 } 2957 2958 const char* JavaThread::get_parent_name() const { 2959 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2960 oop thread_obj = threadObj(); 2961 if (thread_obj != NULL) { 2962 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2963 if (thread_group != NULL) { 2964 oop parent = java_lang_ThreadGroup::parent(thread_group); 2965 if (parent != NULL) { 2966 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2967 // ThreadGroup.name can be null 2968 if (name != NULL) { 2969 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2970 return str; 2971 } 2972 } 2973 } 2974 } 2975 return NULL; 2976 } 2977 2978 ThreadPriority JavaThread::java_priority() const { 2979 oop thr_oop = threadObj(); 2980 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2981 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2982 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2983 return priority; 2984 } 2985 2986 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2987 2988 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2989 // Link Java Thread object <-> C++ Thread 2990 2991 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2992 // and put it into a new Handle. The Handle "thread_oop" can then 2993 // be used to pass the C++ thread object to other methods. 2994 2995 // Set the Java level thread object (jthread) field of the 2996 // new thread (a JavaThread *) to C++ thread object using the 2997 // "thread_oop" handle. 2998 2999 // Set the thread field (a JavaThread *) of the 3000 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3001 3002 Handle thread_oop(Thread::current(), 3003 JNIHandles::resolve_non_null(jni_thread)); 3004 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3005 "must be initialized"); 3006 set_threadObj(thread_oop()); 3007 java_lang_Thread::set_thread(thread_oop(), this); 3008 3009 if (prio == NoPriority) { 3010 prio = java_lang_Thread::priority(thread_oop()); 3011 assert(prio != NoPriority, "A valid priority should be present"); 3012 } 3013 3014 // Push the Java priority down to the native thread; needs Threads_lock 3015 Thread::set_priority(this, prio); 3016 3017 // Add the new thread to the Threads list and set it in motion. 3018 // We must have threads lock in order to call Threads::add. 3019 // It is crucial that we do not block before the thread is 3020 // added to the Threads list for if a GC happens, then the java_thread oop 3021 // will not be visited by GC. 3022 Threads::add(this); 3023 } 3024 3025 oop JavaThread::current_park_blocker() { 3026 // Support for JSR-166 locks 3027 oop thread_oop = threadObj(); 3028 if (thread_oop != NULL && 3029 JDK_Version::current().supports_thread_park_blocker()) { 3030 return java_lang_Thread::park_blocker(thread_oop); 3031 } 3032 return NULL; 3033 } 3034 3035 3036 void JavaThread::print_stack_on(outputStream* st) { 3037 if (!has_last_Java_frame()) return; 3038 ResourceMark rm; 3039 HandleMark hm; 3040 3041 RegisterMap reg_map(this); 3042 vframe* start_vf = last_java_vframe(®_map); 3043 int count = 0; 3044 for (vframe* f = start_vf; f; f = f->sender() ) { 3045 if (f->is_java_frame()) { 3046 javaVFrame* jvf = javaVFrame::cast(f); 3047 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3048 3049 // Print out lock information 3050 if (JavaMonitorsInStackTrace) { 3051 jvf->print_lock_info_on(st, count); 3052 } 3053 } else { 3054 // Ignore non-Java frames 3055 } 3056 3057 // Bail-out case for too deep stacks 3058 count++; 3059 if (MaxJavaStackTraceDepth == count) return; 3060 } 3061 } 3062 3063 3064 // JVMTI PopFrame support 3065 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3066 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3067 if (in_bytes(size_in_bytes) != 0) { 3068 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3069 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3070 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3071 } 3072 } 3073 3074 void* JavaThread::popframe_preserved_args() { 3075 return _popframe_preserved_args; 3076 } 3077 3078 ByteSize JavaThread::popframe_preserved_args_size() { 3079 return in_ByteSize(_popframe_preserved_args_size); 3080 } 3081 3082 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3083 int sz = in_bytes(popframe_preserved_args_size()); 3084 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3085 return in_WordSize(sz / wordSize); 3086 } 3087 3088 void JavaThread::popframe_free_preserved_args() { 3089 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3090 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3091 _popframe_preserved_args = NULL; 3092 _popframe_preserved_args_size = 0; 3093 } 3094 3095 #ifndef PRODUCT 3096 3097 void JavaThread::trace_frames() { 3098 tty->print_cr("[Describe stack]"); 3099 int frame_no = 1; 3100 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3101 tty->print(" %d. ", frame_no++); 3102 fst.current()->print_value_on(tty,this); 3103 tty->cr(); 3104 } 3105 } 3106 3107 class PrintAndVerifyOopClosure: public OopClosure { 3108 protected: 3109 template <class T> inline void do_oop_work(T* p) { 3110 oop obj = oopDesc::load_decode_heap_oop(p); 3111 if (obj == NULL) return; 3112 tty->print(INTPTR_FORMAT ": ", p); 3113 if (obj->is_oop_or_null()) { 3114 if (obj->is_objArray()) { 3115 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3116 } else { 3117 obj->print(); 3118 } 3119 } else { 3120 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3121 } 3122 tty->cr(); 3123 } 3124 public: 3125 virtual void do_oop(oop* p) { do_oop_work(p); } 3126 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3127 }; 3128 3129 3130 static void oops_print(frame* f, const RegisterMap *map) { 3131 PrintAndVerifyOopClosure print; 3132 f->print_value(); 3133 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3134 } 3135 3136 // Print our all the locations that contain oops and whether they are 3137 // valid or not. This useful when trying to find the oldest frame 3138 // where an oop has gone bad since the frame walk is from youngest to 3139 // oldest. 3140 void JavaThread::trace_oops() { 3141 tty->print_cr("[Trace oops]"); 3142 frames_do(oops_print); 3143 } 3144 3145 3146 #ifdef ASSERT 3147 // Print or validate the layout of stack frames 3148 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3149 ResourceMark rm; 3150 PRESERVE_EXCEPTION_MARK; 3151 FrameValues values; 3152 int frame_no = 0; 3153 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3154 fst.current()->describe(values, ++frame_no); 3155 if (depth == frame_no) break; 3156 } 3157 if (validate_only) { 3158 values.validate(); 3159 } else { 3160 tty->print_cr("[Describe stack layout]"); 3161 values.print(this); 3162 } 3163 } 3164 #endif 3165 3166 void JavaThread::trace_stack_from(vframe* start_vf) { 3167 ResourceMark rm; 3168 int vframe_no = 1; 3169 for (vframe* f = start_vf; f; f = f->sender() ) { 3170 if (f->is_java_frame()) { 3171 javaVFrame::cast(f)->print_activation(vframe_no++); 3172 } else { 3173 f->print(); 3174 } 3175 if (vframe_no > StackPrintLimit) { 3176 tty->print_cr("...<more frames>..."); 3177 return; 3178 } 3179 } 3180 } 3181 3182 3183 void JavaThread::trace_stack() { 3184 if (!has_last_Java_frame()) return; 3185 ResourceMark rm; 3186 HandleMark hm; 3187 RegisterMap reg_map(this); 3188 trace_stack_from(last_java_vframe(®_map)); 3189 } 3190 3191 3192 #endif // PRODUCT 3193 3194 3195 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3196 assert(reg_map != NULL, "a map must be given"); 3197 frame f = last_frame(); 3198 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3199 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3200 } 3201 return NULL; 3202 } 3203 3204 3205 Klass* JavaThread::security_get_caller_class(int depth) { 3206 vframeStream vfst(this); 3207 vfst.security_get_caller_frame(depth); 3208 if (!vfst.at_end()) { 3209 return vfst.method()->method_holder(); 3210 } 3211 return NULL; 3212 } 3213 3214 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3215 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3216 CompileBroker::compiler_thread_loop(); 3217 } 3218 3219 // Create a CompilerThread 3220 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3221 : JavaThread(&compiler_thread_entry) { 3222 _env = NULL; 3223 _log = NULL; 3224 _task = NULL; 3225 _queue = queue; 3226 _counters = counters; 3227 _buffer_blob = NULL; 3228 _scanned_nmethod = NULL; 3229 3230 #ifndef PRODUCT 3231 _ideal_graph_printer = NULL; 3232 #endif 3233 } 3234 3235 void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 3236 JavaThread::oops_do(f, cld_f, cf); 3237 if (_scanned_nmethod != NULL && cf != NULL) { 3238 // Safepoints can occur when the sweeper is scanning an nmethod so 3239 // process it here to make sure it isn't unloaded in the middle of 3240 // a scan. 3241 cf->do_code_blob(_scanned_nmethod); 3242 } 3243 } 3244 3245 // ======= Threads ======== 3246 3247 // The Threads class links together all active threads, and provides 3248 // operations over all threads. It is protected by its own Mutex 3249 // lock, which is also used in other contexts to protect thread 3250 // operations from having the thread being operated on from exiting 3251 // and going away unexpectedly (e.g., safepoint synchronization) 3252 3253 JavaThread* Threads::_thread_list = NULL; 3254 int Threads::_number_of_threads = 0; 3255 int Threads::_number_of_non_daemon_threads = 0; 3256 int Threads::_return_code = 0; 3257 size_t JavaThread::_stack_size_at_create = 0; 3258 #ifdef ASSERT 3259 bool Threads::_vm_complete = false; 3260 #endif 3261 3262 // All JavaThreads 3263 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3264 3265 void os_stream(); 3266 3267 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3268 void Threads::threads_do(ThreadClosure* tc) { 3269 assert_locked_or_safepoint(Threads_lock); 3270 // ALL_JAVA_THREADS iterates through all JavaThreads 3271 ALL_JAVA_THREADS(p) { 3272 tc->do_thread(p); 3273 } 3274 // Someday we could have a table or list of all non-JavaThreads. 3275 // For now, just manually iterate through them. 3276 tc->do_thread(VMThread::vm_thread()); 3277 Universe::heap()->gc_threads_do(tc); 3278 WatcherThread *wt = WatcherThread::watcher_thread(); 3279 // Strictly speaking, the following NULL check isn't sufficient to make sure 3280 // the data for WatcherThread is still valid upon being examined. However, 3281 // considering that WatchThread terminates when the VM is on the way to 3282 // exit at safepoint, the chance of the above is extremely small. The right 3283 // way to prevent termination of WatcherThread would be to acquire 3284 // Terminator_lock, but we can't do that without violating the lock rank 3285 // checking in some cases. 3286 if (wt != NULL) 3287 tc->do_thread(wt); 3288 3289 // If CompilerThreads ever become non-JavaThreads, add them here 3290 } 3291 3292 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3293 3294 extern void JDK_Version_init(); 3295 3296 // Check version 3297 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3298 3299 // Initialize the output stream module 3300 ostream_init(); 3301 3302 // Process java launcher properties. 3303 Arguments::process_sun_java_launcher_properties(args); 3304 3305 // Initialize the os module before using TLS 3306 os::init(); 3307 3308 // Initialize system properties. 3309 Arguments::init_system_properties(); 3310 3311 // So that JDK version can be used as a discrimintor when parsing arguments 3312 JDK_Version_init(); 3313 3314 // Update/Initialize System properties after JDK version number is known 3315 Arguments::init_version_specific_system_properties(); 3316 3317 // Parse arguments 3318 jint parse_result = Arguments::parse(args); 3319 if (parse_result != JNI_OK) return parse_result; 3320 3321 if (PauseAtStartup) { 3322 os::pause(); 3323 } 3324 3325 #ifndef USDT2 3326 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3327 #else /* USDT2 */ 3328 HOTSPOT_VM_INIT_BEGIN(); 3329 #endif /* USDT2 */ 3330 3331 // Record VM creation timing statistics 3332 TraceVmCreationTime create_vm_timer; 3333 create_vm_timer.start(); 3334 3335 // Timing (must come after argument parsing) 3336 TraceTime timer("Create VM", TraceStartupTime); 3337 3338 // Initialize the os module after parsing the args 3339 jint os_init_2_result = os::init_2(); 3340 if (os_init_2_result != JNI_OK) return os_init_2_result; 3341 3342 jint adjust_after_os_result = Arguments::adjust_after_os(); 3343 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3344 3345 // intialize TLS 3346 ThreadLocalStorage::init(); 3347 3348 // Bootstrap native memory tracking, so it can start recording memory 3349 // activities before worker thread is started. This is the first phase 3350 // of bootstrapping, VM is currently running in single-thread mode. 3351 MemTracker::bootstrap_single_thread(); 3352 3353 // Initialize output stream logging 3354 ostream_init_log(); 3355 3356 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3357 // Must be before create_vm_init_agents() 3358 if (Arguments::init_libraries_at_startup()) { 3359 convert_vm_init_libraries_to_agents(); 3360 } 3361 3362 // Launch -agentlib/-agentpath and converted -Xrun agents 3363 if (Arguments::init_agents_at_startup()) { 3364 create_vm_init_agents(); 3365 } 3366 3367 // Initialize Threads state 3368 _thread_list = NULL; 3369 _number_of_threads = 0; 3370 _number_of_non_daemon_threads = 0; 3371 3372 // Initialize global data structures and create system classes in heap 3373 vm_init_globals(); 3374 3375 // Attach the main thread to this os thread 3376 JavaThread* main_thread = new JavaThread(); 3377 main_thread->set_thread_state(_thread_in_vm); 3378 // must do this before set_active_handles and initialize_thread_local_storage 3379 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3380 // change the stack size recorded here to one based on the java thread 3381 // stacksize. This adjusted size is what is used to figure the placement 3382 // of the guard pages. 3383 main_thread->record_stack_base_and_size(); 3384 main_thread->initialize_thread_local_storage(); 3385 3386 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3387 3388 if (!main_thread->set_as_starting_thread()) { 3389 vm_shutdown_during_initialization( 3390 "Failed necessary internal allocation. Out of swap space"); 3391 delete main_thread; 3392 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3393 return JNI_ENOMEM; 3394 } 3395 3396 // Enable guard page *after* os::create_main_thread(), otherwise it would 3397 // crash Linux VM, see notes in os_linux.cpp. 3398 main_thread->create_stack_guard_pages(); 3399 3400 // Initialize Java-Level synchronization subsystem 3401 ObjectMonitor::Initialize() ; 3402 3403 // Second phase of bootstrapping, VM is about entering multi-thread mode 3404 MemTracker::bootstrap_multi_thread(); 3405 3406 // Initialize global modules 3407 jint status = init_globals(); 3408 if (status != JNI_OK) { 3409 delete main_thread; 3410 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3411 return status; 3412 } 3413 3414 // Should be done after the heap is fully created 3415 main_thread->cache_global_variables(); 3416 3417 HandleMark hm; 3418 3419 { MutexLocker mu(Threads_lock); 3420 Threads::add(main_thread); 3421 } 3422 3423 // Any JVMTI raw monitors entered in onload will transition into 3424 // real raw monitor. VM is setup enough here for raw monitor enter. 3425 JvmtiExport::transition_pending_onload_raw_monitors(); 3426 3427 // Fully start NMT 3428 MemTracker::start(); 3429 3430 // Create the VMThread 3431 { TraceTime timer("Start VMThread", TraceStartupTime); 3432 VMThread::create(); 3433 Thread* vmthread = VMThread::vm_thread(); 3434 3435 if (!os::create_thread(vmthread, os::vm_thread)) 3436 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3437 3438 // Wait for the VM thread to become ready, and VMThread::run to initialize 3439 // Monitors can have spurious returns, must always check another state flag 3440 { 3441 MutexLocker ml(Notify_lock); 3442 os::start_thread(vmthread); 3443 while (vmthread->active_handles() == NULL) { 3444 Notify_lock->wait(); 3445 } 3446 } 3447 } 3448 3449 assert (Universe::is_fully_initialized(), "not initialized"); 3450 if (VerifyDuringStartup) { 3451 // Make sure we're starting with a clean slate. 3452 VM_Verify verify_op; 3453 VMThread::execute(&verify_op); 3454 } 3455 3456 EXCEPTION_MARK; 3457 3458 // At this point, the Universe is initialized, but we have not executed 3459 // any byte code. Now is a good time (the only time) to dump out the 3460 // internal state of the JVM for sharing. 3461 if (DumpSharedSpaces) { 3462 MetaspaceShared::preload_and_dump(CHECK_0); 3463 ShouldNotReachHere(); 3464 } 3465 3466 // Always call even when there are not JVMTI environments yet, since environments 3467 // may be attached late and JVMTI must track phases of VM execution 3468 JvmtiExport::enter_start_phase(); 3469 3470 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3471 JvmtiExport::post_vm_start(); 3472 3473 { 3474 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3475 3476 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3477 create_vm_init_libraries(); 3478 } 3479 3480 initialize_class(vmSymbols::java_lang_String(), CHECK_0); 3481 3482 if (AggressiveOpts) { 3483 { 3484 // Forcibly initialize java/util/HashMap and mutate the private 3485 // static final "frontCacheEnabled" field before we start creating instances 3486 #ifdef ASSERT 3487 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3488 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 3489 #endif 3490 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3491 KlassHandle k = KlassHandle(THREAD, k_o); 3492 guarantee(k.not_null(), "Must find java/util/HashMap"); 3493 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3494 ik->initialize(CHECK_0); 3495 fieldDescriptor fd; 3496 // Possible we might not find this field; if so, don't break 3497 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3498 k()->java_mirror()->bool_field_put(fd.offset(), true); 3499 } 3500 } 3501 3502 if (UseStringCache) { 3503 // Forcibly initialize java/lang/StringValue and mutate the private 3504 // static final "stringCacheEnabled" field before we start creating instances 3505 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0); 3506 // Possible that StringValue isn't present: if so, silently don't break 3507 if (k_o != NULL) { 3508 KlassHandle k = KlassHandle(THREAD, k_o); 3509 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3510 ik->initialize(CHECK_0); 3511 fieldDescriptor fd; 3512 // Possible we might not find this field: if so, silently don't break 3513 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3514 k()->java_mirror()->bool_field_put(fd.offset(), true); 3515 } 3516 } 3517 } 3518 } 3519 3520 // Initialize java_lang.System (needed before creating the thread) 3521 initialize_class(vmSymbols::java_lang_System(), CHECK_0); 3522 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0); 3523 Handle thread_group = create_initial_thread_group(CHECK_0); 3524 Universe::set_main_thread_group(thread_group()); 3525 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0); 3526 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 3527 main_thread->set_threadObj(thread_object); 3528 // Set thread status to running since main thread has 3529 // been started and running. 3530 java_lang_Thread::set_thread_status(thread_object, 3531 java_lang_Thread::RUNNABLE); 3532 3533 // The VM creates & returns objects of this class. Make sure it's initialized. 3534 initialize_class(vmSymbols::java_lang_Class(), CHECK_0); 3535 3536 // The VM preresolves methods to these classes. Make sure that they get initialized 3537 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0); 3538 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0); 3539 call_initializeSystemClass(CHECK_0); 3540 3541 // get the Java runtime name after java.lang.System is initialized 3542 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3543 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3544 3545 // an instance of OutOfMemory exception has been allocated earlier 3546 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0); 3547 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0); 3548 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0); 3549 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0); 3550 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0); 3551 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0); 3552 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0); 3553 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0); 3554 } 3555 3556 // See : bugid 4211085. 3557 // Background : the static initializer of java.lang.Compiler tries to read 3558 // property"java.compiler" and read & write property "java.vm.info". 3559 // When a security manager is installed through the command line 3560 // option "-Djava.security.manager", the above properties are not 3561 // readable and the static initializer for java.lang.Compiler fails 3562 // resulting in a NoClassDefFoundError. This can happen in any 3563 // user code which calls methods in java.lang.Compiler. 3564 // Hack : the hack is to pre-load and initialize this class, so that only 3565 // system domains are on the stack when the properties are read. 3566 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3567 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3568 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3569 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3570 // Once that is done, we should remove this hack. 3571 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0); 3572 3573 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3574 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3575 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3576 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3577 // This should also be taken out as soon as 4211383 gets fixed. 3578 reset_vm_info_property(CHECK_0); 3579 3580 quicken_jni_functions(); 3581 3582 // Must be run after init_ft which initializes ft_enabled 3583 if (TRACE_INITIALIZE() != JNI_OK) { 3584 vm_exit_during_initialization("Failed to initialize tracing backend"); 3585 } 3586 3587 // Set flag that basic initialization has completed. Used by exceptions and various 3588 // debug stuff, that does not work until all basic classes have been initialized. 3589 set_init_completed(); 3590 3591 #ifndef USDT2 3592 HS_DTRACE_PROBE(hotspot, vm__init__end); 3593 #else /* USDT2 */ 3594 HOTSPOT_VM_INIT_END(); 3595 #endif /* USDT2 */ 3596 3597 // record VM initialization completion time 3598 #if INCLUDE_MANAGEMENT 3599 Management::record_vm_init_completed(); 3600 #endif // INCLUDE_MANAGEMENT 3601 3602 // Compute system loader. Note that this has to occur after set_init_completed, since 3603 // valid exceptions may be thrown in the process. 3604 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3605 // set_init_completed has just been called, causing exceptions not to be shortcut 3606 // anymore. We call vm_exit_during_initialization directly instead. 3607 SystemDictionary::compute_java_system_loader(THREAD); 3608 if (HAS_PENDING_EXCEPTION) { 3609 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3610 } 3611 3612 #if INCLUDE_ALL_GCS 3613 // Support for ConcurrentMarkSweep. This should be cleaned up 3614 // and better encapsulated. The ugly nested if test would go away 3615 // once things are properly refactored. XXX YSR 3616 if (UseConcMarkSweepGC || UseG1GC) { 3617 if (UseConcMarkSweepGC) { 3618 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3619 } else { 3620 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3621 } 3622 if (HAS_PENDING_EXCEPTION) { 3623 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3624 } 3625 } 3626 #endif // INCLUDE_ALL_GCS 3627 3628 // Always call even when there are not JVMTI environments yet, since environments 3629 // may be attached late and JVMTI must track phases of VM execution 3630 JvmtiExport::enter_live_phase(); 3631 3632 // Signal Dispatcher needs to be started before VMInit event is posted 3633 os::signal_init(); 3634 3635 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3636 if (!DisableAttachMechanism) { 3637 if (StartAttachListener || AttachListener::init_at_startup()) { 3638 AttachListener::init(); 3639 } 3640 } 3641 3642 // Launch -Xrun agents 3643 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3644 // back-end can launch with -Xdebug -Xrunjdwp. 3645 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3646 create_vm_init_libraries(); 3647 } 3648 3649 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3650 JvmtiExport::post_vm_initialized(); 3651 3652 if (!TRACE_START()) { 3653 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3654 } 3655 3656 if (CleanChunkPoolAsync) { 3657 Chunk::start_chunk_pool_cleaner_task(); 3658 } 3659 3660 // initialize compiler(s) 3661 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3662 CompileBroker::compilation_init(); 3663 #endif 3664 3665 #if INCLUDE_MANAGEMENT 3666 Management::initialize(THREAD); 3667 #endif // INCLUDE_MANAGEMENT 3668 3669 if (HAS_PENDING_EXCEPTION) { 3670 // management agent fails to start possibly due to 3671 // configuration problem and is responsible for printing 3672 // stack trace if appropriate. Simply exit VM. 3673 vm_exit(1); 3674 } 3675 3676 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3677 if (Arguments::has_alloc_profile()) AllocationProfiler::engage(); 3678 if (MemProfiling) MemProfiler::engage(); 3679 StatSampler::engage(); 3680 if (CheckJNICalls) JniPeriodicChecker::engage(); 3681 3682 BiasedLocking::init(); 3683 3684 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3685 call_postVMInitHook(THREAD); 3686 // The Java side of PostVMInitHook.run must deal with all 3687 // exceptions and provide means of diagnosis. 3688 if (HAS_PENDING_EXCEPTION) { 3689 CLEAR_PENDING_EXCEPTION; 3690 } 3691 } 3692 3693 { 3694 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3695 // Make sure the watcher thread can be started by WatcherThread::start() 3696 // or by dynamic enrollment. 3697 WatcherThread::make_startable(); 3698 // Start up the WatcherThread if there are any periodic tasks 3699 // NOTE: All PeriodicTasks should be registered by now. If they 3700 // aren't, late joiners might appear to start slowly (we might 3701 // take a while to process their first tick). 3702 if (PeriodicTask::num_tasks() > 0) { 3703 WatcherThread::start(); 3704 } 3705 } 3706 3707 // Give os specific code one last chance to start 3708 os::init_3(); 3709 3710 create_vm_timer.end(); 3711 #ifdef ASSERT 3712 _vm_complete = true; 3713 #endif 3714 return JNI_OK; 3715 } 3716 3717 // type for the Agent_OnLoad and JVM_OnLoad entry points 3718 extern "C" { 3719 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3720 } 3721 // Find a command line agent library and return its entry point for 3722 // -agentlib: -agentpath: -Xrun 3723 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3724 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3725 OnLoadEntry_t on_load_entry = NULL; 3726 void *library = agent->os_lib(); // check if we have looked it up before 3727 3728 if (library == NULL) { 3729 char buffer[JVM_MAXPATHLEN]; 3730 char ebuf[1024]; 3731 const char *name = agent->name(); 3732 const char *msg = "Could not find agent library "; 3733 3734 if (agent->is_absolute_path()) { 3735 library = os::dll_load(name, ebuf, sizeof ebuf); 3736 if (library == NULL) { 3737 const char *sub_msg = " in absolute path, with error: "; 3738 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3739 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3740 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3741 // If we can't find the agent, exit. 3742 vm_exit_during_initialization(buf, NULL); 3743 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3744 } 3745 } else { 3746 // Try to load the agent from the standard dll directory 3747 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3748 name)) { 3749 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3750 } 3751 if (library == NULL) { // Try the local directory 3752 char ns[1] = {0}; 3753 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3754 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3755 } 3756 if (library == NULL) { 3757 const char *sub_msg = " on the library path, with error: "; 3758 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3759 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3760 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3761 // If we can't find the agent, exit. 3762 vm_exit_during_initialization(buf, NULL); 3763 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3764 } 3765 } 3766 } 3767 agent->set_os_lib(library); 3768 } 3769 3770 // Find the OnLoad function. 3771 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3772 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index])); 3773 if (on_load_entry != NULL) break; 3774 } 3775 return on_load_entry; 3776 } 3777 3778 // Find the JVM_OnLoad entry point 3779 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3780 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3781 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3782 } 3783 3784 // Find the Agent_OnLoad entry point 3785 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3786 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3787 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3788 } 3789 3790 // For backwards compatibility with -Xrun 3791 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3792 // treated like -agentpath: 3793 // Must be called before agent libraries are created 3794 void Threads::convert_vm_init_libraries_to_agents() { 3795 AgentLibrary* agent; 3796 AgentLibrary* next; 3797 3798 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3799 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3800 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3801 3802 // If there is an JVM_OnLoad function it will get called later, 3803 // otherwise see if there is an Agent_OnLoad 3804 if (on_load_entry == NULL) { 3805 on_load_entry = lookup_agent_on_load(agent); 3806 if (on_load_entry != NULL) { 3807 // switch it to the agent list -- so that Agent_OnLoad will be called, 3808 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3809 Arguments::convert_library_to_agent(agent); 3810 } else { 3811 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3812 } 3813 } 3814 } 3815 } 3816 3817 // Create agents for -agentlib: -agentpath: and converted -Xrun 3818 // Invokes Agent_OnLoad 3819 // Called very early -- before JavaThreads exist 3820 void Threads::create_vm_init_agents() { 3821 extern struct JavaVM_ main_vm; 3822 AgentLibrary* agent; 3823 3824 JvmtiExport::enter_onload_phase(); 3825 3826 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3827 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3828 3829 if (on_load_entry != NULL) { 3830 // Invoke the Agent_OnLoad function 3831 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3832 if (err != JNI_OK) { 3833 vm_exit_during_initialization("agent library failed to init", agent->name()); 3834 } 3835 } else { 3836 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3837 } 3838 } 3839 JvmtiExport::enter_primordial_phase(); 3840 } 3841 3842 extern "C" { 3843 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3844 } 3845 3846 void Threads::shutdown_vm_agents() { 3847 // Send any Agent_OnUnload notifications 3848 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3849 extern struct JavaVM_ main_vm; 3850 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3851 3852 // Find the Agent_OnUnload function. 3853 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3854 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3855 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3856 3857 // Invoke the Agent_OnUnload function 3858 if (unload_entry != NULL) { 3859 JavaThread* thread = JavaThread::current(); 3860 ThreadToNativeFromVM ttn(thread); 3861 HandleMark hm(thread); 3862 (*unload_entry)(&main_vm); 3863 break; 3864 } 3865 } 3866 } 3867 } 3868 3869 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3870 // Invokes JVM_OnLoad 3871 void Threads::create_vm_init_libraries() { 3872 extern struct JavaVM_ main_vm; 3873 AgentLibrary* agent; 3874 3875 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3876 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3877 3878 if (on_load_entry != NULL) { 3879 // Invoke the JVM_OnLoad function 3880 JavaThread* thread = JavaThread::current(); 3881 ThreadToNativeFromVM ttn(thread); 3882 HandleMark hm(thread); 3883 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3884 if (err != JNI_OK) { 3885 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3886 } 3887 } else { 3888 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3889 } 3890 } 3891 } 3892 3893 // Last thread running calls java.lang.Shutdown.shutdown() 3894 void JavaThread::invoke_shutdown_hooks() { 3895 HandleMark hm(this); 3896 3897 // We could get here with a pending exception, if so clear it now. 3898 if (this->has_pending_exception()) { 3899 this->clear_pending_exception(); 3900 } 3901 3902 EXCEPTION_MARK; 3903 Klass* k = 3904 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3905 THREAD); 3906 if (k != NULL) { 3907 // SystemDictionary::resolve_or_null will return null if there was 3908 // an exception. If we cannot load the Shutdown class, just don't 3909 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3910 // and finalizers (if runFinalizersOnExit is set) won't be run. 3911 // Note that if a shutdown hook was registered or runFinalizersOnExit 3912 // was called, the Shutdown class would have already been loaded 3913 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3914 instanceKlassHandle shutdown_klass (THREAD, k); 3915 JavaValue result(T_VOID); 3916 JavaCalls::call_static(&result, 3917 shutdown_klass, 3918 vmSymbols::shutdown_method_name(), 3919 vmSymbols::void_method_signature(), 3920 THREAD); 3921 } 3922 CLEAR_PENDING_EXCEPTION; 3923 } 3924 3925 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3926 // the program falls off the end of main(). Another VM exit path is through 3927 // vm_exit() when the program calls System.exit() to return a value or when 3928 // there is a serious error in VM. The two shutdown paths are not exactly 3929 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3930 // and VM_Exit op at VM level. 3931 // 3932 // Shutdown sequence: 3933 // + Shutdown native memory tracking if it is on 3934 // + Wait until we are the last non-daemon thread to execute 3935 // <-- every thing is still working at this moment --> 3936 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3937 // shutdown hooks, run finalizers if finalization-on-exit 3938 // + Call before_exit(), prepare for VM exit 3939 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3940 // currently the only user of this mechanism is File.deleteOnExit()) 3941 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3942 // post thread end and vm death events to JVMTI, 3943 // stop signal thread 3944 // + Call JavaThread::exit(), it will: 3945 // > release JNI handle blocks, remove stack guard pages 3946 // > remove this thread from Threads list 3947 // <-- no more Java code from this thread after this point --> 3948 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3949 // the compiler threads at safepoint 3950 // <-- do not use anything that could get blocked by Safepoint --> 3951 // + Disable tracing at JNI/JVM barriers 3952 // + Set _vm_exited flag for threads that are still running native code 3953 // + Delete this thread 3954 // + Call exit_globals() 3955 // > deletes tty 3956 // > deletes PerfMemory resources 3957 // + Return to caller 3958 3959 bool Threads::destroy_vm() { 3960 JavaThread* thread = JavaThread::current(); 3961 3962 #ifdef ASSERT 3963 _vm_complete = false; 3964 #endif 3965 // Wait until we are the last non-daemon thread to execute 3966 { MutexLocker nu(Threads_lock); 3967 while (Threads::number_of_non_daemon_threads() > 1 ) 3968 // This wait should make safepoint checks, wait without a timeout, 3969 // and wait as a suspend-equivalent condition. 3970 // 3971 // Note: If the FlatProfiler is running and this thread is waiting 3972 // for another non-daemon thread to finish, then the FlatProfiler 3973 // is waiting for the external suspend request on this thread to 3974 // complete. wait_for_ext_suspend_completion() will eventually 3975 // timeout, but that takes time. Making this wait a suspend- 3976 // equivalent condition solves that timeout problem. 3977 // 3978 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3979 Mutex::_as_suspend_equivalent_flag); 3980 } 3981 3982 // Hang forever on exit if we are reporting an error. 3983 if (ShowMessageBoxOnError && is_error_reported()) { 3984 os::infinite_sleep(); 3985 } 3986 os::wait_for_keypress_at_exit(); 3987 3988 if (JDK_Version::is_jdk12x_version()) { 3989 // We are the last thread running, so check if finalizers should be run. 3990 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3991 HandleMark rm(thread); 3992 Universe::run_finalizers_on_exit(); 3993 } else { 3994 // run Java level shutdown hooks 3995 thread->invoke_shutdown_hooks(); 3996 } 3997 3998 before_exit(thread); 3999 4000 thread->exit(true); 4001 4002 // Stop VM thread. 4003 { 4004 // 4945125 The vm thread comes to a safepoint during exit. 4005 // GC vm_operations can get caught at the safepoint, and the 4006 // heap is unparseable if they are caught. Grab the Heap_lock 4007 // to prevent this. The GC vm_operations will not be able to 4008 // queue until after the vm thread is dead. 4009 // After this point, we'll never emerge out of the safepoint before 4010 // the VM exits, so concurrent GC threads do not need to be explicitly 4011 // stopped; they remain inactive until the process exits. 4012 // Note: some concurrent G1 threads may be running during a safepoint, 4013 // but these will not be accessing the heap, just some G1-specific side 4014 // data structures that are not accessed by any other threads but them 4015 // after this point in a terminal safepoint. 4016 4017 MutexLocker ml(Heap_lock); 4018 4019 VMThread::wait_for_vm_thread_exit(); 4020 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4021 VMThread::destroy(); 4022 } 4023 4024 // clean up ideal graph printers 4025 #if defined(COMPILER2) && !defined(PRODUCT) 4026 IdealGraphPrinter::clean_up(); 4027 #endif 4028 4029 // Now, all Java threads are gone except daemon threads. Daemon threads 4030 // running Java code or in VM are stopped by the Safepoint. However, 4031 // daemon threads executing native code are still running. But they 4032 // will be stopped at native=>Java/VM barriers. Note that we can't 4033 // simply kill or suspend them, as it is inherently deadlock-prone. 4034 4035 #ifndef PRODUCT 4036 // disable function tracing at JNI/JVM barriers 4037 TraceJNICalls = false; 4038 TraceJVMCalls = false; 4039 TraceRuntimeCalls = false; 4040 #endif 4041 4042 VM_Exit::set_vm_exited(); 4043 4044 notify_vm_shutdown(); 4045 4046 delete thread; 4047 4048 // exit_globals() will delete tty 4049 exit_globals(); 4050 4051 return true; 4052 } 4053 4054 4055 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4056 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4057 return is_supported_jni_version(version); 4058 } 4059 4060 4061 jboolean Threads::is_supported_jni_version(jint version) { 4062 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4063 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4064 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4065 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4066 return JNI_FALSE; 4067 } 4068 4069 4070 void Threads::add(JavaThread* p, bool force_daemon) { 4071 // The threads lock must be owned at this point 4072 assert_locked_or_safepoint(Threads_lock); 4073 4074 // See the comment for this method in thread.hpp for its purpose and 4075 // why it is called here. 4076 p->initialize_queues(); 4077 p->set_next(_thread_list); 4078 _thread_list = p; 4079 _number_of_threads++; 4080 oop threadObj = p->threadObj(); 4081 bool daemon = true; 4082 // Bootstrapping problem: threadObj can be null for initial 4083 // JavaThread (or for threads attached via JNI) 4084 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4085 _number_of_non_daemon_threads++; 4086 daemon = false; 4087 } 4088 4089 p->set_safepoint_visible(true); 4090 4091 ThreadService::add_thread(p, daemon); 4092 4093 // Possible GC point. 4094 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4095 } 4096 4097 void Threads::remove(JavaThread* p) { 4098 // Extra scope needed for Thread_lock, so we can check 4099 // that we do not remove thread without safepoint code notice 4100 { MutexLocker ml(Threads_lock); 4101 4102 assert(includes(p), "p must be present"); 4103 4104 JavaThread* current = _thread_list; 4105 JavaThread* prev = NULL; 4106 4107 while (current != p) { 4108 prev = current; 4109 current = current->next(); 4110 } 4111 4112 if (prev) { 4113 prev->set_next(current->next()); 4114 } else { 4115 _thread_list = p->next(); 4116 } 4117 _number_of_threads--; 4118 oop threadObj = p->threadObj(); 4119 bool daemon = true; 4120 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4121 _number_of_non_daemon_threads--; 4122 daemon = false; 4123 4124 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4125 // on destroy_vm will wake up. 4126 if (number_of_non_daemon_threads() == 1) 4127 Threads_lock->notify_all(); 4128 } 4129 ThreadService::remove_thread(p, daemon); 4130 4131 // Make sure that safepoint code disregard this thread. This is needed since 4132 // the thread might mess around with locks after this point. This can cause it 4133 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4134 // of this thread since it is removed from the queue. 4135 p->set_terminated_value(); 4136 4137 // Now, this thread is not visible to safepoint 4138 p->set_safepoint_visible(false); 4139 // once the thread becomes safepoint invisible, we can not use its per-thread 4140 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4141 // to release its per-thread recorder here. 4142 MemTracker::thread_exiting(p); 4143 } // unlock Threads_lock 4144 4145 // Since Events::log uses a lock, we grab it outside the Threads_lock 4146 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4147 } 4148 4149 // Threads_lock must be held when this is called (or must be called during a safepoint) 4150 bool Threads::includes(JavaThread* p) { 4151 assert(Threads_lock->is_locked(), "sanity check"); 4152 ALL_JAVA_THREADS(q) { 4153 if (q == p ) { 4154 return true; 4155 } 4156 } 4157 return false; 4158 } 4159 4160 // Operations on the Threads list for GC. These are not explicitly locked, 4161 // but the garbage collector must provide a safe context for them to run. 4162 // In particular, these things should never be called when the Threads_lock 4163 // is held by some other thread. (Note: the Safepoint abstraction also 4164 // uses the Threads_lock to gurantee this property. It also makes sure that 4165 // all threads gets blocked when exiting or starting). 4166 4167 void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4168 ALL_JAVA_THREADS(p) { 4169 p->oops_do(f, cld_f, cf); 4170 } 4171 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4172 } 4173 4174 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4175 // Introduce a mechanism allowing parallel threads to claim threads as 4176 // root groups. Overhead should be small enough to use all the time, 4177 // even in sequential code. 4178 SharedHeap* sh = SharedHeap::heap(); 4179 // Cannot yet substitute active_workers for n_par_threads 4180 // because of G1CollectedHeap::verify() use of 4181 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4182 // turn off parallelism in process_strong_roots while active_workers 4183 // is being used for parallelism elsewhere. 4184 bool is_par = sh->n_par_threads() > 0; 4185 assert(!is_par || 4186 (SharedHeap::heap()->n_par_threads() == 4187 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4188 int cp = SharedHeap::heap()->strong_roots_parity(); 4189 ALL_JAVA_THREADS(p) { 4190 if (p->claim_oops_do(is_par, cp)) { 4191 p->oops_do(f, cld_f, cf); 4192 } 4193 } 4194 VMThread* vmt = VMThread::vm_thread(); 4195 if (vmt->claim_oops_do(is_par, cp)) { 4196 vmt->oops_do(f, cld_f, cf); 4197 } 4198 } 4199 4200 #if INCLUDE_ALL_GCS 4201 // Used by ParallelScavenge 4202 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4203 ALL_JAVA_THREADS(p) { 4204 q->enqueue(new ThreadRootsTask(p)); 4205 } 4206 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4207 } 4208 4209 // Used by Parallel Old 4210 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4211 ALL_JAVA_THREADS(p) { 4212 q->enqueue(new ThreadRootsMarkingTask(p)); 4213 } 4214 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4215 } 4216 #endif // INCLUDE_ALL_GCS 4217 4218 void Threads::nmethods_do(CodeBlobClosure* cf) { 4219 ALL_JAVA_THREADS(p) { 4220 p->nmethods_do(cf); 4221 } 4222 VMThread::vm_thread()->nmethods_do(cf); 4223 } 4224 4225 void Threads::metadata_do(void f(Metadata*)) { 4226 ALL_JAVA_THREADS(p) { 4227 p->metadata_do(f); 4228 } 4229 } 4230 4231 void Threads::gc_epilogue() { 4232 ALL_JAVA_THREADS(p) { 4233 p->gc_epilogue(); 4234 } 4235 } 4236 4237 void Threads::gc_prologue() { 4238 ALL_JAVA_THREADS(p) { 4239 p->gc_prologue(); 4240 } 4241 } 4242 4243 void Threads::deoptimized_wrt_marked_nmethods() { 4244 ALL_JAVA_THREADS(p) { 4245 p->deoptimized_wrt_marked_nmethods(); 4246 } 4247 } 4248 4249 4250 // Get count Java threads that are waiting to enter the specified monitor. 4251 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4252 address monitor, bool doLock) { 4253 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4254 "must grab Threads_lock or be at safepoint"); 4255 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4256 4257 int i = 0; 4258 { 4259 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4260 ALL_JAVA_THREADS(p) { 4261 if (p->is_Compiler_thread()) continue; 4262 4263 address pending = (address)p->current_pending_monitor(); 4264 if (pending == monitor) { // found a match 4265 if (i < count) result->append(p); // save the first count matches 4266 i++; 4267 } 4268 } 4269 } 4270 return result; 4271 } 4272 4273 4274 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4275 assert(doLock || 4276 Threads_lock->owned_by_self() || 4277 SafepointSynchronize::is_at_safepoint(), 4278 "must grab Threads_lock or be at safepoint"); 4279 4280 // NULL owner means not locked so we can skip the search 4281 if (owner == NULL) return NULL; 4282 4283 { 4284 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4285 ALL_JAVA_THREADS(p) { 4286 // first, see if owner is the address of a Java thread 4287 if (owner == (address)p) return p; 4288 } 4289 } 4290 // Cannot assert on lack of success here since this function may be 4291 // used by code that is trying to report useful problem information 4292 // like deadlock detection. 4293 if (UseHeavyMonitors) return NULL; 4294 4295 // 4296 // If we didn't find a matching Java thread and we didn't force use of 4297 // heavyweight monitors, then the owner is the stack address of the 4298 // Lock Word in the owning Java thread's stack. 4299 // 4300 JavaThread* the_owner = NULL; 4301 { 4302 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4303 ALL_JAVA_THREADS(q) { 4304 if (q->is_lock_owned(owner)) { 4305 the_owner = q; 4306 break; 4307 } 4308 } 4309 } 4310 // cannot assert on lack of success here; see above comment 4311 return the_owner; 4312 } 4313 4314 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4315 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4316 char buf[32]; 4317 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4318 4319 st->print_cr("Full thread dump %s (%s %s):", 4320 Abstract_VM_Version::vm_name(), 4321 Abstract_VM_Version::vm_release(), 4322 Abstract_VM_Version::vm_info_string() 4323 ); 4324 st->cr(); 4325 4326 #if INCLUDE_ALL_GCS 4327 // Dump concurrent locks 4328 ConcurrentLocksDump concurrent_locks; 4329 if (print_concurrent_locks) { 4330 concurrent_locks.dump_at_safepoint(); 4331 } 4332 #endif // INCLUDE_ALL_GCS 4333 4334 ALL_JAVA_THREADS(p) { 4335 ResourceMark rm; 4336 p->print_on(st); 4337 if (print_stacks) { 4338 if (internal_format) { 4339 p->trace_stack(); 4340 } else { 4341 p->print_stack_on(st); 4342 } 4343 } 4344 st->cr(); 4345 #if INCLUDE_ALL_GCS 4346 if (print_concurrent_locks) { 4347 concurrent_locks.print_locks_on(p, st); 4348 } 4349 #endif // INCLUDE_ALL_GCS 4350 } 4351 4352 VMThread::vm_thread()->print_on(st); 4353 st->cr(); 4354 Universe::heap()->print_gc_threads_on(st); 4355 WatcherThread* wt = WatcherThread::watcher_thread(); 4356 if (wt != NULL) { 4357 wt->print_on(st); 4358 st->cr(); 4359 } 4360 CompileBroker::print_compiler_threads_on(st); 4361 st->flush(); 4362 } 4363 4364 // Threads::print_on_error() is called by fatal error handler. It's possible 4365 // that VM is not at safepoint and/or current thread is inside signal handler. 4366 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4367 // memory (even in resource area), it might deadlock the error handler. 4368 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4369 bool found_current = false; 4370 st->print_cr("Java Threads: ( => current thread )"); 4371 ALL_JAVA_THREADS(thread) { 4372 bool is_current = (current == thread); 4373 found_current = found_current || is_current; 4374 4375 st->print("%s", is_current ? "=>" : " "); 4376 4377 st->print(PTR_FORMAT, thread); 4378 st->print(" "); 4379 thread->print_on_error(st, buf, buflen); 4380 st->cr(); 4381 } 4382 st->cr(); 4383 4384 st->print_cr("Other Threads:"); 4385 if (VMThread::vm_thread()) { 4386 bool is_current = (current == VMThread::vm_thread()); 4387 found_current = found_current || is_current; 4388 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4389 4390 st->print(PTR_FORMAT, VMThread::vm_thread()); 4391 st->print(" "); 4392 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4393 st->cr(); 4394 } 4395 WatcherThread* wt = WatcherThread::watcher_thread(); 4396 if (wt != NULL) { 4397 bool is_current = (current == wt); 4398 found_current = found_current || is_current; 4399 st->print("%s", is_current ? "=>" : " "); 4400 4401 st->print(PTR_FORMAT, wt); 4402 st->print(" "); 4403 wt->print_on_error(st, buf, buflen); 4404 st->cr(); 4405 } 4406 if (!found_current) { 4407 st->cr(); 4408 st->print("=>" PTR_FORMAT " (exited) ", current); 4409 current->print_on_error(st, buf, buflen); 4410 st->cr(); 4411 } 4412 } 4413 4414 // Internal SpinLock and Mutex 4415 // Based on ParkEvent 4416 4417 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4418 // 4419 // We employ SpinLocks _only for low-contention, fixed-length 4420 // short-duration critical sections where we're concerned 4421 // about native mutex_t or HotSpot Mutex:: latency. 4422 // The mux construct provides a spin-then-block mutual exclusion 4423 // mechanism. 4424 // 4425 // Testing has shown that contention on the ListLock guarding gFreeList 4426 // is common. If we implement ListLock as a simple SpinLock it's common 4427 // for the JVM to devolve to yielding with little progress. This is true 4428 // despite the fact that the critical sections protected by ListLock are 4429 // extremely short. 4430 // 4431 // TODO-FIXME: ListLock should be of type SpinLock. 4432 // We should make this a 1st-class type, integrated into the lock 4433 // hierarchy as leaf-locks. Critically, the SpinLock structure 4434 // should have sufficient padding to avoid false-sharing and excessive 4435 // cache-coherency traffic. 4436 4437 4438 typedef volatile int SpinLockT ; 4439 4440 void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4441 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4442 return ; // normal fast-path return 4443 } 4444 4445 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4446 TEVENT (SpinAcquire - ctx) ; 4447 int ctr = 0 ; 4448 int Yields = 0 ; 4449 for (;;) { 4450 while (*adr != 0) { 4451 ++ctr ; 4452 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4453 if (Yields > 5) { 4454 // Consider using a simple NakedSleep() instead. 4455 // Then SpinAcquire could be called by non-JVM threads 4456 Thread::current()->_ParkEvent->park(1) ; 4457 } else { 4458 os::NakedYield() ; 4459 ++Yields ; 4460 } 4461 } else { 4462 SpinPause() ; 4463 } 4464 } 4465 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4466 } 4467 } 4468 4469 void Thread::SpinRelease (volatile int * adr) { 4470 assert (*adr != 0, "invariant") ; 4471 OrderAccess::fence() ; // guarantee at least release consistency. 4472 // Roach-motel semantics. 4473 // It's safe if subsequent LDs and STs float "up" into the critical section, 4474 // but prior LDs and STs within the critical section can't be allowed 4475 // to reorder or float past the ST that releases the lock. 4476 *adr = 0 ; 4477 } 4478 4479 // muxAcquire and muxRelease: 4480 // 4481 // * muxAcquire and muxRelease support a single-word lock-word construct. 4482 // The LSB of the word is set IFF the lock is held. 4483 // The remainder of the word points to the head of a singly-linked list 4484 // of threads blocked on the lock. 4485 // 4486 // * The current implementation of muxAcquire-muxRelease uses its own 4487 // dedicated Thread._MuxEvent instance. If we're interested in 4488 // minimizing the peak number of extant ParkEvent instances then 4489 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4490 // as certain invariants were satisfied. Specifically, care would need 4491 // to be taken with regards to consuming unpark() "permits". 4492 // A safe rule of thumb is that a thread would never call muxAcquire() 4493 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4494 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4495 // consume an unpark() permit intended for monitorenter, for instance. 4496 // One way around this would be to widen the restricted-range semaphore 4497 // implemented in park(). Another alternative would be to provide 4498 // multiple instances of the PlatformEvent() for each thread. One 4499 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4500 // 4501 // * Usage: 4502 // -- Only as leaf locks 4503 // -- for short-term locking only as muxAcquire does not perform 4504 // thread state transitions. 4505 // 4506 // Alternatives: 4507 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4508 // but with parking or spin-then-park instead of pure spinning. 4509 // * Use Taura-Oyama-Yonenzawa locks. 4510 // * It's possible to construct a 1-0 lock if we encode the lockword as 4511 // (List,LockByte). Acquire will CAS the full lockword while Release 4512 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4513 // acquiring threads use timers (ParkTimed) to detect and recover from 4514 // the stranding window. Thread/Node structures must be aligned on 256-byte 4515 // boundaries by using placement-new. 4516 // * Augment MCS with advisory back-link fields maintained with CAS(). 4517 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4518 // The validity of the backlinks must be ratified before we trust the value. 4519 // If the backlinks are invalid the exiting thread must back-track through the 4520 // the forward links, which are always trustworthy. 4521 // * Add a successor indication. The LockWord is currently encoded as 4522 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4523 // to provide the usual futile-wakeup optimization. 4524 // See RTStt for details. 4525 // * Consider schedctl.sc_nopreempt to cover the critical section. 4526 // 4527 4528 4529 typedef volatile intptr_t MutexT ; // Mux Lock-word 4530 enum MuxBits { LOCKBIT = 1 } ; 4531 4532 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4533 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4534 if (w == 0) return ; 4535 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4536 return ; 4537 } 4538 4539 TEVENT (muxAcquire - Contention) ; 4540 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4541 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4542 for (;;) { 4543 int its = (os::is_MP() ? 100 : 0) + 1 ; 4544 4545 // Optional spin phase: spin-then-park strategy 4546 while (--its >= 0) { 4547 w = *Lock ; 4548 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4549 return ; 4550 } 4551 } 4552 4553 Self->reset() ; 4554 Self->OnList = intptr_t(Lock) ; 4555 // The following fence() isn't _strictly necessary as the subsequent 4556 // CAS() both serializes execution and ratifies the fetched *Lock value. 4557 OrderAccess::fence(); 4558 for (;;) { 4559 w = *Lock ; 4560 if ((w & LOCKBIT) == 0) { 4561 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4562 Self->OnList = 0 ; // hygiene - allows stronger asserts 4563 return ; 4564 } 4565 continue ; // Interference -- *Lock changed -- Just retry 4566 } 4567 assert (w & LOCKBIT, "invariant") ; 4568 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4569 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4570 } 4571 4572 while (Self->OnList != 0) { 4573 Self->park() ; 4574 } 4575 } 4576 } 4577 4578 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4579 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4580 if (w == 0) return ; 4581 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4582 return ; 4583 } 4584 4585 TEVENT (muxAcquire - Contention) ; 4586 ParkEvent * ReleaseAfter = NULL ; 4587 if (ev == NULL) { 4588 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4589 } 4590 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4591 for (;;) { 4592 guarantee (ev->OnList == 0, "invariant") ; 4593 int its = (os::is_MP() ? 100 : 0) + 1 ; 4594 4595 // Optional spin phase: spin-then-park strategy 4596 while (--its >= 0) { 4597 w = *Lock ; 4598 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4599 if (ReleaseAfter != NULL) { 4600 ParkEvent::Release (ReleaseAfter) ; 4601 } 4602 return ; 4603 } 4604 } 4605 4606 ev->reset() ; 4607 ev->OnList = intptr_t(Lock) ; 4608 // The following fence() isn't _strictly necessary as the subsequent 4609 // CAS() both serializes execution and ratifies the fetched *Lock value. 4610 OrderAccess::fence(); 4611 for (;;) { 4612 w = *Lock ; 4613 if ((w & LOCKBIT) == 0) { 4614 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4615 ev->OnList = 0 ; 4616 // We call ::Release while holding the outer lock, thus 4617 // artificially lengthening the critical section. 4618 // Consider deferring the ::Release() until the subsequent unlock(), 4619 // after we've dropped the outer lock. 4620 if (ReleaseAfter != NULL) { 4621 ParkEvent::Release (ReleaseAfter) ; 4622 } 4623 return ; 4624 } 4625 continue ; // Interference -- *Lock changed -- Just retry 4626 } 4627 assert (w & LOCKBIT, "invariant") ; 4628 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4629 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4630 } 4631 4632 while (ev->OnList != 0) { 4633 ev->park() ; 4634 } 4635 } 4636 } 4637 4638 // Release() must extract a successor from the list and then wake that thread. 4639 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4640 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4641 // Release() would : 4642 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4643 // (B) Extract a successor from the private list "in-hand" 4644 // (C) attempt to CAS() the residual back into *Lock over null. 4645 // If there were any newly arrived threads and the CAS() would fail. 4646 // In that case Release() would detach the RATs, re-merge the list in-hand 4647 // with the RATs and repeat as needed. Alternately, Release() might 4648 // detach and extract a successor, but then pass the residual list to the wakee. 4649 // The wakee would be responsible for reattaching and remerging before it 4650 // competed for the lock. 4651 // 4652 // Both "pop" and DMR are immune from ABA corruption -- there can be 4653 // multiple concurrent pushers, but only one popper or detacher. 4654 // This implementation pops from the head of the list. This is unfair, 4655 // but tends to provide excellent throughput as hot threads remain hot. 4656 // (We wake recently run threads first). 4657 4658 void Thread::muxRelease (volatile intptr_t * Lock) { 4659 for (;;) { 4660 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4661 assert (w & LOCKBIT, "invariant") ; 4662 if (w == LOCKBIT) return ; 4663 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4664 assert (List != NULL, "invariant") ; 4665 assert (List->OnList == intptr_t(Lock), "invariant") ; 4666 ParkEvent * nxt = List->ListNext ; 4667 4668 // The following CAS() releases the lock and pops the head element. 4669 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4670 continue ; 4671 } 4672 List->OnList = 0 ; 4673 OrderAccess::fence() ; 4674 List->unpark () ; 4675 return ; 4676 } 4677 } 4678 4679 4680 void Threads::verify() { 4681 ALL_JAVA_THREADS(p) { 4682 p->verify(); 4683 } 4684 VMThread* thread = VMThread::vm_thread(); 4685 if (thread != NULL) thread->verify(); 4686 }