1 /* 2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/classLoader.hpp" 27 #include "classfile/javaClasses.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/scopeDesc.hpp" 31 #include "compiler/compileBroker.hpp" 32 #include "interpreter/interpreter.hpp" 33 #include "interpreter/linkResolver.hpp" 34 #include "interpreter/oopMapCache.hpp" 35 #include "jvmtifiles/jvmtiEnv.hpp" 36 #include "memory/gcLocker.inline.hpp" 37 #include "memory/metaspaceShared.hpp" 38 #include "memory/oopFactory.hpp" 39 #include "memory/universe.inline.hpp" 40 #include "oops/instanceKlass.hpp" 41 #include "oops/objArrayOop.hpp" 42 #include "oops/oop.inline.hpp" 43 #include "oops/symbol.hpp" 44 #include "prims/jvm_misc.hpp" 45 #include "prims/jvmtiExport.hpp" 46 #include "prims/jvmtiThreadState.hpp" 47 #include "prims/privilegedStack.hpp" 48 #include "runtime/arguments.hpp" 49 #include "runtime/atomic.inline.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/orderAccess.inline.hpp" 63 #include "runtime/osThread.hpp" 64 #include "runtime/safepoint.hpp" 65 #include "runtime/sharedRuntime.hpp" 66 #include "runtime/statSampler.hpp" 67 #include "runtime/stubRoutines.hpp" 68 #include "runtime/task.hpp" 69 #include "runtime/thread.inline.hpp" 70 #include "runtime/threadCritical.hpp" 71 #include "runtime/threadLocalStorage.hpp" 72 #include "runtime/vframe.hpp" 73 #include "runtime/vframeArray.hpp" 74 #include "runtime/vframe_hp.hpp" 75 #include "runtime/vmThread.hpp" 76 #include "runtime/vm_operations.hpp" 77 #include "services/attachListener.hpp" 78 #include "services/management.hpp" 79 #include "services/memTracker.hpp" 80 #include "services/threadService.hpp" 81 #include "trace/tracing.hpp" 82 #include "trace/traceMacros.hpp" 83 #include "utilities/defaultStream.hpp" 84 #include "utilities/dtrace.hpp" 85 #include "utilities/events.hpp" 86 #include "utilities/preserveException.hpp" 87 #include "utilities/macros.hpp" 88 #if INCLUDE_ALL_GCS 89 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 90 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 91 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 92 #endif // INCLUDE_ALL_GCS 93 #ifdef COMPILER1 94 #include "c1/c1_Compiler.hpp" 95 #endif 96 #ifdef COMPILER2 97 #include "opto/c2compiler.hpp" 98 #include "opto/idealGraphPrinter.hpp" 99 #endif 100 #if INCLUDE_RTM_OPT 101 #include "runtime/rtmLocking.hpp" 102 #endif 103 104 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 105 106 #ifdef DTRACE_ENABLED 107 108 // Only bother with this argument setup if dtrace is available 109 110 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 111 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 112 113 #define DTRACE_THREAD_PROBE(probe, javathread) \ 114 { \ 115 ResourceMark rm(this); \ 116 int len = 0; \ 117 const char* name = (javathread)->get_thread_name(); \ 118 len = strlen(name); \ 119 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 120 (char *) name, len, \ 121 java_lang_Thread::thread_id((javathread)->threadObj()), \ 122 (uintptr_t) (javathread)->osthread()->thread_id(), \ 123 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 124 } 125 126 #else // ndef DTRACE_ENABLED 127 128 #define DTRACE_THREAD_PROBE(probe, javathread) 129 130 #endif // ndef DTRACE_ENABLED 131 132 133 // Class hierarchy 134 // - Thread 135 // - VMThread 136 // - WatcherThread 137 // - ConcurrentMarkSweepThread 138 // - JavaThread 139 // - CompilerThread 140 141 // ======= Thread ======== 142 // Support for forcing alignment of thread objects for biased locking 143 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 144 if (UseBiasedLocking) { 145 const int alignment = markOopDesc::biased_lock_alignment; 146 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 147 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 148 : AllocateHeap(aligned_size, flags, CURRENT_PC, 149 AllocFailStrategy::RETURN_NULL); 150 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 151 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 152 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 153 "JavaThread alignment code overflowed allocated storage"); 154 if (TraceBiasedLocking) { 155 if (aligned_addr != real_malloc_addr) 156 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 157 real_malloc_addr, aligned_addr); 158 } 159 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 160 return aligned_addr; 161 } else { 162 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 163 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 164 } 165 } 166 167 void Thread::operator delete(void* p) { 168 if (UseBiasedLocking) { 169 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 170 FreeHeap(real_malloc_addr, mtThread); 171 } else { 172 FreeHeap(p, mtThread); 173 } 174 } 175 176 177 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 178 // JavaThread 179 180 181 Thread::Thread() { 182 // stack and get_thread 183 set_stack_base(NULL); 184 set_stack_size(0); 185 set_self_raw_id(0); 186 set_lgrp_id(-1); 187 188 // allocated data structures 189 set_osthread(NULL); 190 set_resource_area(new (mtThread)ResourceArea()); 191 DEBUG_ONLY(_current_resource_mark = NULL;) 192 set_handle_area(new (mtThread) HandleArea(NULL)); 193 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 194 set_active_handles(NULL); 195 set_free_handle_block(NULL); 196 set_last_handle_mark(NULL); 197 198 // This initial value ==> never claimed. 199 _oops_do_parity = 0; 200 201 // the handle mark links itself to last_handle_mark 202 new HandleMark(this); 203 204 // plain initialization 205 debug_only(_owned_locks = NULL;) 206 debug_only(_allow_allocation_count = 0;) 207 NOT_PRODUCT(_allow_safepoint_count = 0;) 208 NOT_PRODUCT(_skip_gcalot = false;) 209 _jvmti_env_iteration_count = 0; 210 set_allocated_bytes(0); 211 _vm_operation_started_count = 0; 212 _vm_operation_completed_count = 0; 213 _current_pending_monitor = NULL; 214 _current_pending_monitor_is_from_java = true; 215 _current_waiting_monitor = NULL; 216 _num_nested_signal = 0; 217 omFreeList = NULL; 218 omFreeCount = 0; 219 omFreeProvision = 32; 220 omInUseList = NULL; 221 omInUseCount = 0; 222 223 #ifdef ASSERT 224 _visited_for_critical_count = false; 225 #endif 226 227 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 228 _suspend_flags = 0; 229 230 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 231 _hashStateX = os::random(); 232 _hashStateY = 842502087; 233 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 234 _hashStateW = 273326509; 235 236 _OnTrap = 0; 237 _schedctl = NULL; 238 _Stalled = 0; 239 _TypeTag = 0x2BAD; 240 241 // Many of the following fields are effectively final - immutable 242 // Note that nascent threads can't use the Native Monitor-Mutex 243 // construct until the _MutexEvent is initialized ... 244 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 245 // we might instead use a stack of ParkEvents that we could provision on-demand. 246 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 247 // and ::Release() 248 _ParkEvent = ParkEvent::Allocate(this); 249 _SleepEvent = ParkEvent::Allocate(this); 250 _MutexEvent = ParkEvent::Allocate(this); 251 _MuxEvent = ParkEvent::Allocate(this); 252 253 #ifdef CHECK_UNHANDLED_OOPS 254 if (CheckUnhandledOops) { 255 _unhandled_oops = new UnhandledOops(this); 256 } 257 #endif // CHECK_UNHANDLED_OOPS 258 #ifdef ASSERT 259 if (UseBiasedLocking) { 260 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 261 assert(this == _real_malloc_address || 262 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 263 "bug in forced alignment of thread objects"); 264 } 265 #endif /* ASSERT */ 266 } 267 268 void Thread::initialize_thread_local_storage() { 269 // Note: Make sure this method only calls 270 // non-blocking operations. Otherwise, it might not work 271 // with the thread-startup/safepoint interaction. 272 273 // During Java thread startup, safepoint code should allow this 274 // method to complete because it may need to allocate memory to 275 // store information for the new thread. 276 277 // initialize structure dependent on thread local storage 278 ThreadLocalStorage::set_thread(this); 279 } 280 281 void Thread::record_stack_base_and_size() { 282 set_stack_base(os::current_stack_base()); 283 set_stack_size(os::current_stack_size()); 284 if (is_Java_thread()) { 285 ((JavaThread*) this)->set_stack_overflow_limit(); 286 } 287 // CR 7190089: on Solaris, primordial thread's stack is adjusted 288 // in initialize_thread(). Without the adjustment, stack size is 289 // incorrect if stack is set to unlimited (ulimit -s unlimited). 290 // So far, only Solaris has real implementation of initialize_thread(). 291 // 292 // set up any platform-specific state. 293 os::initialize_thread(this); 294 295 #if INCLUDE_NMT 296 // record thread's native stack, stack grows downward 297 address stack_low_addr = stack_base() - stack_size(); 298 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 299 CURRENT_PC); 300 #endif // INCLUDE_NMT 301 } 302 303 304 Thread::~Thread() { 305 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 306 ObjectSynchronizer::omFlush(this); 307 308 EVENT_THREAD_DESTRUCT(this); 309 310 // stack_base can be NULL if the thread is never started or exited before 311 // record_stack_base_and_size called. Although, we would like to ensure 312 // that all started threads do call record_stack_base_and_size(), there is 313 // not proper way to enforce that. 314 #if INCLUDE_NMT 315 if (_stack_base != NULL) { 316 address low_stack_addr = stack_base() - stack_size(); 317 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); 318 #ifdef ASSERT 319 set_stack_base(NULL); 320 #endif 321 } 322 #endif // INCLUDE_NMT 323 324 // deallocate data structures 325 delete resource_area(); 326 // since the handle marks are using the handle area, we have to deallocated the root 327 // handle mark before deallocating the thread's handle area, 328 assert(last_handle_mark() != NULL, "check we have an element"); 329 delete last_handle_mark(); 330 assert(last_handle_mark() == NULL, "check we have reached the end"); 331 332 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 333 // We NULL out the fields for good hygiene. 334 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 335 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 336 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 337 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 338 339 delete handle_area(); 340 delete metadata_handles(); 341 342 // osthread() can be NULL, if creation of thread failed. 343 if (osthread() != NULL) os::free_thread(osthread()); 344 345 delete _SR_lock; 346 347 // clear thread local storage if the Thread is deleting itself 348 if (this == Thread::current()) { 349 ThreadLocalStorage::set_thread(NULL); 350 } else { 351 // In the case where we're not the current thread, invalidate all the 352 // caches in case some code tries to get the current thread or the 353 // thread that was destroyed, and gets stale information. 354 ThreadLocalStorage::invalidate_all(); 355 } 356 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 357 } 358 359 // NOTE: dummy function for assertion purpose. 360 void Thread::run() { 361 ShouldNotReachHere(); 362 } 363 364 #ifdef ASSERT 365 // Private method to check for dangling thread pointer 366 void check_for_dangling_thread_pointer(Thread *thread) { 367 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 368 "possibility of dangling Thread pointer"); 369 } 370 #endif 371 372 373 #ifndef PRODUCT 374 // Tracing method for basic thread operations 375 void Thread::trace(const char* msg, const Thread* const thread) { 376 if (!TraceThreadEvents) return; 377 ResourceMark rm; 378 ThreadCritical tc; 379 const char *name = "non-Java thread"; 380 int prio = -1; 381 if (thread->is_Java_thread() 382 && !thread->is_Compiler_thread()) { 383 // The Threads_lock must be held to get information about 384 // this thread but may not be in some situations when 385 // tracing thread events. 386 bool release_Threads_lock = false; 387 if (!Threads_lock->owned_by_self()) { 388 Threads_lock->lock(); 389 release_Threads_lock = true; 390 } 391 JavaThread* jt = (JavaThread *)thread; 392 name = (char *)jt->get_thread_name(); 393 oop thread_oop = jt->threadObj(); 394 if (thread_oop != NULL) { 395 prio = java_lang_Thread::priority(thread_oop); 396 } 397 if (release_Threads_lock) { 398 Threads_lock->unlock(); 399 } 400 } 401 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 402 } 403 #endif 404 405 406 ThreadPriority Thread::get_priority(const Thread* const thread) { 407 trace("get priority", thread); 408 ThreadPriority priority; 409 // Can return an error! 410 (void)os::get_priority(thread, priority); 411 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 412 return priority; 413 } 414 415 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 416 trace("set priority", thread); 417 debug_only(check_for_dangling_thread_pointer(thread);) 418 // Can return an error! 419 (void)os::set_priority(thread, priority); 420 } 421 422 423 void Thread::start(Thread* thread) { 424 trace("start", thread); 425 // Start is different from resume in that its safety is guaranteed by context or 426 // being called from a Java method synchronized on the Thread object. 427 if (!DisableStartThread) { 428 if (thread->is_Java_thread()) { 429 // Initialize the thread state to RUNNABLE before starting this thread. 430 // Can not set it after the thread started because we do not know the 431 // exact thread state at that time. It could be in MONITOR_WAIT or 432 // in SLEEPING or some other state. 433 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 434 java_lang_Thread::RUNNABLE); 435 } 436 os::start_thread(thread); 437 } 438 } 439 440 // Enqueue a VM_Operation to do the job for us - sometime later 441 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 442 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 443 VMThread::execute(vm_stop); 444 } 445 446 447 // 448 // Check if an external suspend request has completed (or has been 449 // cancelled). Returns true if the thread is externally suspended and 450 // false otherwise. 451 // 452 // The bits parameter returns information about the code path through 453 // the routine. Useful for debugging: 454 // 455 // set in is_ext_suspend_completed(): 456 // 0x00000001 - routine was entered 457 // 0x00000010 - routine return false at end 458 // 0x00000100 - thread exited (return false) 459 // 0x00000200 - suspend request cancelled (return false) 460 // 0x00000400 - thread suspended (return true) 461 // 0x00001000 - thread is in a suspend equivalent state (return true) 462 // 0x00002000 - thread is native and walkable (return true) 463 // 0x00004000 - thread is native_trans and walkable (needed retry) 464 // 465 // set in wait_for_ext_suspend_completion(): 466 // 0x00010000 - routine was entered 467 // 0x00020000 - suspend request cancelled before loop (return false) 468 // 0x00040000 - thread suspended before loop (return true) 469 // 0x00080000 - suspend request cancelled in loop (return false) 470 // 0x00100000 - thread suspended in loop (return true) 471 // 0x00200000 - suspend not completed during retry loop (return false) 472 // 473 474 // Helper class for tracing suspend wait debug bits. 475 // 476 // 0x00000100 indicates that the target thread exited before it could 477 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 478 // 0x00080000 each indicate a cancelled suspend request so they don't 479 // count as wait failures either. 480 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 481 482 class TraceSuspendDebugBits : public StackObj { 483 private: 484 JavaThread * jt; 485 bool is_wait; 486 bool called_by_wait; // meaningful when !is_wait 487 uint32_t * bits; 488 489 public: 490 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 491 uint32_t *_bits) { 492 jt = _jt; 493 is_wait = _is_wait; 494 called_by_wait = _called_by_wait; 495 bits = _bits; 496 } 497 498 ~TraceSuspendDebugBits() { 499 if (!is_wait) { 500 #if 1 501 // By default, don't trace bits for is_ext_suspend_completed() calls. 502 // That trace is very chatty. 503 return; 504 #else 505 if (!called_by_wait) { 506 // If tracing for is_ext_suspend_completed() is enabled, then only 507 // trace calls to it from wait_for_ext_suspend_completion() 508 return; 509 } 510 #endif 511 } 512 513 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 514 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 515 MutexLocker ml(Threads_lock); // needed for get_thread_name() 516 ResourceMark rm; 517 518 tty->print_cr( 519 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 520 jt->get_thread_name(), *bits); 521 522 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 523 } 524 } 525 } 526 }; 527 #undef DEBUG_FALSE_BITS 528 529 530 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 531 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 532 533 bool did_trans_retry = false; // only do thread_in_native_trans retry once 534 bool do_trans_retry; // flag to force the retry 535 536 *bits |= 0x00000001; 537 538 do { 539 do_trans_retry = false; 540 541 if (is_exiting()) { 542 // Thread is in the process of exiting. This is always checked 543 // first to reduce the risk of dereferencing a freed JavaThread. 544 *bits |= 0x00000100; 545 return false; 546 } 547 548 if (!is_external_suspend()) { 549 // Suspend request is cancelled. This is always checked before 550 // is_ext_suspended() to reduce the risk of a rogue resume 551 // confusing the thread that made the suspend request. 552 *bits |= 0x00000200; 553 return false; 554 } 555 556 if (is_ext_suspended()) { 557 // thread is suspended 558 *bits |= 0x00000400; 559 return true; 560 } 561 562 // Now that we no longer do hard suspends of threads running 563 // native code, the target thread can be changing thread state 564 // while we are in this routine: 565 // 566 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 567 // 568 // We save a copy of the thread state as observed at this moment 569 // and make our decision about suspend completeness based on the 570 // copy. This closes the race where the thread state is seen as 571 // _thread_in_native_trans in the if-thread_blocked check, but is 572 // seen as _thread_blocked in if-thread_in_native_trans check. 573 JavaThreadState save_state = thread_state(); 574 575 if (save_state == _thread_blocked && is_suspend_equivalent()) { 576 // If the thread's state is _thread_blocked and this blocking 577 // condition is known to be equivalent to a suspend, then we can 578 // consider the thread to be externally suspended. This means that 579 // the code that sets _thread_blocked has been modified to do 580 // self-suspension if the blocking condition releases. We also 581 // used to check for CONDVAR_WAIT here, but that is now covered by 582 // the _thread_blocked with self-suspension check. 583 // 584 // Return true since we wouldn't be here unless there was still an 585 // external suspend request. 586 *bits |= 0x00001000; 587 return true; 588 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 589 // Threads running native code will self-suspend on native==>VM/Java 590 // transitions. If its stack is walkable (should always be the case 591 // unless this function is called before the actual java_suspend() 592 // call), then the wait is done. 593 *bits |= 0x00002000; 594 return true; 595 } else if (!called_by_wait && !did_trans_retry && 596 save_state == _thread_in_native_trans && 597 frame_anchor()->walkable()) { 598 // The thread is transitioning from thread_in_native to another 599 // thread state. check_safepoint_and_suspend_for_native_trans() 600 // will force the thread to self-suspend. If it hasn't gotten 601 // there yet we may have caught the thread in-between the native 602 // code check above and the self-suspend. Lucky us. If we were 603 // called by wait_for_ext_suspend_completion(), then it 604 // will be doing the retries so we don't have to. 605 // 606 // Since we use the saved thread state in the if-statement above, 607 // there is a chance that the thread has already transitioned to 608 // _thread_blocked by the time we get here. In that case, we will 609 // make a single unnecessary pass through the logic below. This 610 // doesn't hurt anything since we still do the trans retry. 611 612 *bits |= 0x00004000; 613 614 // Once the thread leaves thread_in_native_trans for another 615 // thread state, we break out of this retry loop. We shouldn't 616 // need this flag to prevent us from getting back here, but 617 // sometimes paranoia is good. 618 did_trans_retry = true; 619 620 // We wait for the thread to transition to a more usable state. 621 for (int i = 1; i <= SuspendRetryCount; i++) { 622 // We used to do an "os::yield_all(i)" call here with the intention 623 // that yielding would increase on each retry. However, the parameter 624 // is ignored on Linux which means the yield didn't scale up. Waiting 625 // on the SR_lock below provides a much more predictable scale up for 626 // the delay. It also provides a simple/direct point to check for any 627 // safepoint requests from the VMThread 628 629 // temporarily drops SR_lock while doing wait with safepoint check 630 // (if we're a JavaThread - the WatcherThread can also call this) 631 // and increase delay with each retry 632 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 633 634 // check the actual thread state instead of what we saved above 635 if (thread_state() != _thread_in_native_trans) { 636 // the thread has transitioned to another thread state so 637 // try all the checks (except this one) one more time. 638 do_trans_retry = true; 639 break; 640 } 641 } // end retry loop 642 643 644 } 645 } while (do_trans_retry); 646 647 *bits |= 0x00000010; 648 return false; 649 } 650 651 // 652 // Wait for an external suspend request to complete (or be cancelled). 653 // Returns true if the thread is externally suspended and false otherwise. 654 // 655 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 656 uint32_t *bits) { 657 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 658 false /* !called_by_wait */, bits); 659 660 // local flag copies to minimize SR_lock hold time 661 bool is_suspended; 662 bool pending; 663 uint32_t reset_bits; 664 665 // set a marker so is_ext_suspend_completed() knows we are the caller 666 *bits |= 0x00010000; 667 668 // We use reset_bits to reinitialize the bits value at the top of 669 // each retry loop. This allows the caller to make use of any 670 // unused bits for their own marking purposes. 671 reset_bits = *bits; 672 673 { 674 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 675 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 676 delay, bits); 677 pending = is_external_suspend(); 678 } 679 // must release SR_lock to allow suspension to complete 680 681 if (!pending) { 682 // A cancelled suspend request is the only false return from 683 // is_ext_suspend_completed() that keeps us from entering the 684 // retry loop. 685 *bits |= 0x00020000; 686 return false; 687 } 688 689 if (is_suspended) { 690 *bits |= 0x00040000; 691 return true; 692 } 693 694 for (int i = 1; i <= retries; i++) { 695 *bits = reset_bits; // reinit to only track last retry 696 697 // We used to do an "os::yield_all(i)" call here with the intention 698 // that yielding would increase on each retry. However, the parameter 699 // is ignored on Linux which means the yield didn't scale up. Waiting 700 // on the SR_lock below provides a much more predictable scale up for 701 // the delay. It also provides a simple/direct point to check for any 702 // safepoint requests from the VMThread 703 704 { 705 MutexLocker ml(SR_lock()); 706 // wait with safepoint check (if we're a JavaThread - the WatcherThread 707 // can also call this) and increase delay with each retry 708 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 709 710 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 711 delay, bits); 712 713 // It is possible for the external suspend request to be cancelled 714 // (by a resume) before the actual suspend operation is completed. 715 // Refresh our local copy to see if we still need to wait. 716 pending = is_external_suspend(); 717 } 718 719 if (!pending) { 720 // A cancelled suspend request is the only false return from 721 // is_ext_suspend_completed() that keeps us from staying in the 722 // retry loop. 723 *bits |= 0x00080000; 724 return false; 725 } 726 727 if (is_suspended) { 728 *bits |= 0x00100000; 729 return true; 730 } 731 } // end retry loop 732 733 // thread did not suspend after all our retries 734 *bits |= 0x00200000; 735 return false; 736 } 737 738 #ifndef PRODUCT 739 void JavaThread::record_jump(address target, address instr, const char* file, int line) { 740 741 // This should not need to be atomic as the only way for simultaneous 742 // updates is via interrupts. Even then this should be rare or non-existent 743 // and we don't care that much anyway. 744 745 int index = _jmp_ring_index; 746 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 747 _jmp_ring[index]._target = (intptr_t) target; 748 _jmp_ring[index]._instruction = (intptr_t) instr; 749 _jmp_ring[index]._file = file; 750 _jmp_ring[index]._line = line; 751 } 752 #endif /* PRODUCT */ 753 754 // Called by flat profiler 755 // Callers have already called wait_for_ext_suspend_completion 756 // The assertion for that is currently too complex to put here: 757 bool JavaThread::profile_last_Java_frame(frame* _fr) { 758 bool gotframe = false; 759 // self suspension saves needed state. 760 if (has_last_Java_frame() && _anchor.walkable()) { 761 *_fr = pd_last_frame(); 762 gotframe = true; 763 } 764 return gotframe; 765 } 766 767 void Thread::interrupt(Thread* thread) { 768 trace("interrupt", thread); 769 debug_only(check_for_dangling_thread_pointer(thread);) 770 os::interrupt(thread); 771 } 772 773 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 774 trace("is_interrupted", thread); 775 debug_only(check_for_dangling_thread_pointer(thread);) 776 // Note: If clear_interrupted==false, this simply fetches and 777 // returns the value of the field osthread()->interrupted(). 778 return os::is_interrupted(thread, clear_interrupted); 779 } 780 781 782 // GC Support 783 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 784 jint thread_parity = _oops_do_parity; 785 if (thread_parity != strong_roots_parity) { 786 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 787 if (res == thread_parity) { 788 return true; 789 } else { 790 guarantee(res == strong_roots_parity, "Or else what?"); 791 assert(SharedHeap::heap()->workers()->active_workers() > 0, 792 "Should only fail when parallel."); 793 return false; 794 } 795 } 796 assert(SharedHeap::heap()->workers()->active_workers() > 0, 797 "Should only fail when parallel."); 798 return false; 799 } 800 801 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 802 active_handles()->oops_do(f); 803 // Do oop for ThreadShadow 804 f->do_oop((oop*)&_pending_exception); 805 handle_area()->oops_do(f); 806 } 807 808 void Thread::nmethods_do(CodeBlobClosure* cf) { 809 // no nmethods in a generic thread... 810 } 811 812 void Thread::metadata_do(void f(Metadata*)) { 813 if (metadata_handles() != NULL) { 814 for (int i = 0; i< metadata_handles()->length(); i++) { 815 f(metadata_handles()->at(i)); 816 } 817 } 818 } 819 820 void Thread::print_on(outputStream* st) const { 821 // get_priority assumes osthread initialized 822 if (osthread() != NULL) { 823 int os_prio; 824 if (os::get_native_priority(this, &os_prio) == OS_OK) { 825 st->print("os_prio=%d ", os_prio); 826 } 827 st->print("tid=" INTPTR_FORMAT " ", this); 828 osthread()->print_on(st); 829 } 830 debug_only(if (WizardMode) print_owned_locks_on(st);) 831 } 832 833 // Thread::print_on_error() is called by fatal error handler. Don't use 834 // any lock or allocate memory. 835 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 836 if (is_VM_thread()) st->print("VMThread"); 837 else if (is_Compiler_thread()) st->print("CompilerThread"); 838 else if (is_Java_thread()) st->print("JavaThread"); 839 else if (is_GC_task_thread()) st->print("GCTaskThread"); 840 else if (is_Watcher_thread()) st->print("WatcherThread"); 841 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 842 else st->print("Thread"); 843 844 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 845 _stack_base - _stack_size, _stack_base); 846 847 if (osthread()) { 848 st->print(" [id=%d]", osthread()->thread_id()); 849 } 850 } 851 852 #ifdef ASSERT 853 void Thread::print_owned_locks_on(outputStream* st) const { 854 Monitor *cur = _owned_locks; 855 if (cur == NULL) { 856 st->print(" (no locks) "); 857 } else { 858 st->print_cr(" Locks owned:"); 859 while (cur) { 860 cur->print_on(st); 861 cur = cur->next(); 862 } 863 } 864 } 865 866 static int ref_use_count = 0; 867 868 bool Thread::owns_locks_but_compiled_lock() const { 869 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 870 if (cur != Compile_lock) return true; 871 } 872 return false; 873 } 874 875 876 #endif 877 878 #ifndef PRODUCT 879 880 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 881 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 882 // no threads which allow_vm_block's are held 883 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 884 // Check if current thread is allowed to block at a safepoint 885 if (!(_allow_safepoint_count == 0)) 886 fatal("Possible safepoint reached by thread that does not allow it"); 887 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 888 fatal("LEAF method calling lock?"); 889 } 890 891 #ifdef ASSERT 892 if (potential_vm_operation && is_Java_thread() 893 && !Universe::is_bootstrapping()) { 894 // Make sure we do not hold any locks that the VM thread also uses. 895 // This could potentially lead to deadlocks 896 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 897 // Threads_lock is special, since the safepoint synchronization will not start before this is 898 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 899 // since it is used to transfer control between JavaThreads and the VMThread 900 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 901 if ((cur->allow_vm_block() && 902 cur != Threads_lock && 903 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 904 cur != VMOperationRequest_lock && 905 cur != VMOperationQueue_lock) || 906 cur->rank() == Mutex::special) { 907 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name())); 908 } 909 } 910 } 911 912 if (GCALotAtAllSafepoints) { 913 // We could enter a safepoint here and thus have a gc 914 InterfaceSupport::check_gc_alot(); 915 } 916 #endif 917 } 918 #endif 919 920 bool Thread::is_in_stack(address adr) const { 921 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 922 address end = os::current_stack_pointer(); 923 // Allow non Java threads to call this without stack_base 924 if (_stack_base == NULL) return true; 925 if (stack_base() >= adr && adr >= end) return true; 926 927 return false; 928 } 929 930 931 bool Thread::is_in_usable_stack(address adr) const { 932 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 933 size_t usable_stack_size = _stack_size - stack_guard_size; 934 935 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 936 } 937 938 939 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 940 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 941 // used for compilation in the future. If that change is made, the need for these methods 942 // should be revisited, and they should be removed if possible. 943 944 bool Thread::is_lock_owned(address adr) const { 945 return on_local_stack(adr); 946 } 947 948 bool Thread::set_as_starting_thread() { 949 // NOTE: this must be called inside the main thread. 950 return os::create_main_thread((JavaThread*)this); 951 } 952 953 static void initialize_class(Symbol* class_name, TRAPS) { 954 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 955 InstanceKlass::cast(klass)->initialize(CHECK); 956 } 957 958 959 // Creates the initial ThreadGroup 960 static Handle create_initial_thread_group(TRAPS) { 961 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 962 instanceKlassHandle klass (THREAD, k); 963 964 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 965 { 966 JavaValue result(T_VOID); 967 JavaCalls::call_special(&result, 968 system_instance, 969 klass, 970 vmSymbols::object_initializer_name(), 971 vmSymbols::void_method_signature(), 972 CHECK_NH); 973 } 974 Universe::set_system_thread_group(system_instance()); 975 976 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 977 { 978 JavaValue result(T_VOID); 979 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 980 JavaCalls::call_special(&result, 981 main_instance, 982 klass, 983 vmSymbols::object_initializer_name(), 984 vmSymbols::threadgroup_string_void_signature(), 985 system_instance, 986 string, 987 CHECK_NH); 988 } 989 return main_instance; 990 } 991 992 // Creates the initial Thread 993 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 994 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 995 instanceKlassHandle klass (THREAD, k); 996 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 997 998 java_lang_Thread::set_thread(thread_oop(), thread); 999 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1000 thread->set_threadObj(thread_oop()); 1001 1002 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1003 1004 JavaValue result(T_VOID); 1005 JavaCalls::call_special(&result, thread_oop, 1006 klass, 1007 vmSymbols::object_initializer_name(), 1008 vmSymbols::threadgroup_string_void_signature(), 1009 thread_group, 1010 string, 1011 CHECK_NULL); 1012 return thread_oop(); 1013 } 1014 1015 static void call_initializeSystemClass(TRAPS) { 1016 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1017 instanceKlassHandle klass (THREAD, k); 1018 1019 JavaValue result(T_VOID); 1020 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1021 vmSymbols::void_method_signature(), CHECK); 1022 } 1023 1024 char java_runtime_name[128] = ""; 1025 char java_runtime_version[128] = ""; 1026 1027 // extract the JRE name from sun.misc.Version.java_runtime_name 1028 static const char* get_java_runtime_name(TRAPS) { 1029 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1030 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1031 fieldDescriptor fd; 1032 bool found = k != NULL && 1033 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1034 vmSymbols::string_signature(), &fd); 1035 if (found) { 1036 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1037 if (name_oop == NULL) 1038 return NULL; 1039 const char* name = java_lang_String::as_utf8_string(name_oop, 1040 java_runtime_name, 1041 sizeof(java_runtime_name)); 1042 return name; 1043 } else { 1044 return NULL; 1045 } 1046 } 1047 1048 // extract the JRE version from sun.misc.Version.java_runtime_version 1049 static const char* get_java_runtime_version(TRAPS) { 1050 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1051 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1052 fieldDescriptor fd; 1053 bool found = k != NULL && 1054 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1055 vmSymbols::string_signature(), &fd); 1056 if (found) { 1057 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1058 if (name_oop == NULL) 1059 return NULL; 1060 const char* name = java_lang_String::as_utf8_string(name_oop, 1061 java_runtime_version, 1062 sizeof(java_runtime_version)); 1063 return name; 1064 } else { 1065 return NULL; 1066 } 1067 } 1068 1069 // General purpose hook into Java code, run once when the VM is initialized. 1070 // The Java library method itself may be changed independently from the VM. 1071 static void call_postVMInitHook(TRAPS) { 1072 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1073 instanceKlassHandle klass (THREAD, k); 1074 if (klass.not_null()) { 1075 JavaValue result(T_VOID); 1076 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1077 vmSymbols::void_method_signature(), 1078 CHECK); 1079 } 1080 } 1081 1082 static void reset_vm_info_property(TRAPS) { 1083 // the vm info string 1084 ResourceMark rm(THREAD); 1085 const char *vm_info = VM_Version::vm_info_string(); 1086 1087 // java.lang.System class 1088 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1089 instanceKlassHandle klass (THREAD, k); 1090 1091 // setProperty arguments 1092 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1093 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1094 1095 // return value 1096 JavaValue r(T_OBJECT); 1097 1098 // public static String setProperty(String key, String value); 1099 JavaCalls::call_static(&r, 1100 klass, 1101 vmSymbols::setProperty_name(), 1102 vmSymbols::string_string_string_signature(), 1103 key_str, 1104 value_str, 1105 CHECK); 1106 } 1107 1108 1109 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1110 assert(thread_group.not_null(), "thread group should be specified"); 1111 assert(threadObj() == NULL, "should only create Java thread object once"); 1112 1113 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1114 instanceKlassHandle klass (THREAD, k); 1115 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1116 1117 java_lang_Thread::set_thread(thread_oop(), this); 1118 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1119 set_threadObj(thread_oop()); 1120 1121 JavaValue result(T_VOID); 1122 if (thread_name != NULL) { 1123 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1124 // Thread gets assigned specified name and null target 1125 JavaCalls::call_special(&result, 1126 thread_oop, 1127 klass, 1128 vmSymbols::object_initializer_name(), 1129 vmSymbols::threadgroup_string_void_signature(), 1130 thread_group, // Argument 1 1131 name, // Argument 2 1132 THREAD); 1133 } else { 1134 // Thread gets assigned name "Thread-nnn" and null target 1135 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1136 JavaCalls::call_special(&result, 1137 thread_oop, 1138 klass, 1139 vmSymbols::object_initializer_name(), 1140 vmSymbols::threadgroup_runnable_void_signature(), 1141 thread_group, // Argument 1 1142 Handle(), // Argument 2 1143 THREAD); 1144 } 1145 1146 1147 if (daemon) { 1148 java_lang_Thread::set_daemon(thread_oop()); 1149 } 1150 1151 if (HAS_PENDING_EXCEPTION) { 1152 return; 1153 } 1154 1155 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1156 Handle threadObj(this, this->threadObj()); 1157 1158 JavaCalls::call_special(&result, 1159 thread_group, 1160 group, 1161 vmSymbols::add_method_name(), 1162 vmSymbols::thread_void_signature(), 1163 threadObj, // Arg 1 1164 THREAD); 1165 1166 1167 } 1168 1169 // NamedThread -- non-JavaThread subclasses with multiple 1170 // uniquely named instances should derive from this. 1171 NamedThread::NamedThread() : Thread() { 1172 _name = NULL; 1173 _processed_thread = NULL; 1174 } 1175 1176 NamedThread::~NamedThread() { 1177 if (_name != NULL) { 1178 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1179 _name = NULL; 1180 } 1181 } 1182 1183 void NamedThread::set_name(const char* format, ...) { 1184 guarantee(_name == NULL, "Only get to set name once."); 1185 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1186 guarantee(_name != NULL, "alloc failure"); 1187 va_list ap; 1188 va_start(ap, format); 1189 jio_vsnprintf(_name, max_name_len, format, ap); 1190 va_end(ap); 1191 } 1192 1193 void NamedThread::print_on(outputStream* st) const { 1194 st->print("\"%s\" ", name()); 1195 Thread::print_on(st); 1196 st->cr(); 1197 } 1198 1199 1200 // ======= WatcherThread ======== 1201 1202 // The watcher thread exists to simulate timer interrupts. It should 1203 // be replaced by an abstraction over whatever native support for 1204 // timer interrupts exists on the platform. 1205 1206 WatcherThread* WatcherThread::_watcher_thread = NULL; 1207 bool WatcherThread::_startable = false; 1208 volatile bool WatcherThread::_should_terminate = false; 1209 1210 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1211 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1212 if (os::create_thread(this, os::watcher_thread)) { 1213 _watcher_thread = this; 1214 1215 // Set the watcher thread to the highest OS priority which should not be 1216 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1217 // is created. The only normal thread using this priority is the reference 1218 // handler thread, which runs for very short intervals only. 1219 // If the VMThread's priority is not lower than the WatcherThread profiling 1220 // will be inaccurate. 1221 os::set_priority(this, MaxPriority); 1222 if (!DisableStartThread) { 1223 os::start_thread(this); 1224 } 1225 } 1226 } 1227 1228 int WatcherThread::sleep() const { 1229 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1230 1231 // remaining will be zero if there are no tasks, 1232 // causing the WatcherThread to sleep until a task is 1233 // enrolled 1234 int remaining = PeriodicTask::time_to_wait(); 1235 int time_slept = 0; 1236 1237 // we expect this to timeout - we only ever get unparked when 1238 // we should terminate or when a new task has been enrolled 1239 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1240 1241 jlong time_before_loop = os::javaTimeNanos(); 1242 1243 for (;;) { 1244 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1245 jlong now = os::javaTimeNanos(); 1246 1247 if (remaining == 0) { 1248 // if we didn't have any tasks we could have waited for a long time 1249 // consider the time_slept zero and reset time_before_loop 1250 time_slept = 0; 1251 time_before_loop = now; 1252 } else { 1253 // need to recalculate since we might have new tasks in _tasks 1254 time_slept = (int) ((now - time_before_loop) / 1000000); 1255 } 1256 1257 // Change to task list or spurious wakeup of some kind 1258 if (timedout || _should_terminate) { 1259 break; 1260 } 1261 1262 remaining = PeriodicTask::time_to_wait(); 1263 if (remaining == 0) { 1264 // Last task was just disenrolled so loop around and wait until 1265 // another task gets enrolled 1266 continue; 1267 } 1268 1269 remaining -= time_slept; 1270 if (remaining <= 0) 1271 break; 1272 } 1273 1274 return time_slept; 1275 } 1276 1277 void WatcherThread::run() { 1278 assert(this == watcher_thread(), "just checking"); 1279 1280 this->record_stack_base_and_size(); 1281 this->initialize_thread_local_storage(); 1282 this->set_active_handles(JNIHandleBlock::allocate_block()); 1283 while (!_should_terminate) { 1284 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1285 assert(watcher_thread() == this, "thread consistency check"); 1286 1287 // Calculate how long it'll be until the next PeriodicTask work 1288 // should be done, and sleep that amount of time. 1289 int time_waited = sleep(); 1290 1291 if (is_error_reported()) { 1292 // A fatal error has happened, the error handler(VMError::report_and_die) 1293 // should abort JVM after creating an error log file. However in some 1294 // rare cases, the error handler itself might deadlock. Here we try to 1295 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1296 // 1297 // This code is in WatcherThread because WatcherThread wakes up 1298 // periodically so the fatal error handler doesn't need to do anything; 1299 // also because the WatcherThread is less likely to crash than other 1300 // threads. 1301 1302 for (;;) { 1303 if (!ShowMessageBoxOnError 1304 && (OnError == NULL || OnError[0] == '\0') 1305 && Arguments::abort_hook() == NULL) { 1306 os::sleep(this, 2 * 60 * 1000, false); 1307 fdStream err(defaultStream::output_fd()); 1308 err.print_raw_cr("# [ timer expired, abort... ]"); 1309 // skip atexit/vm_exit/vm_abort hooks 1310 os::die(); 1311 } 1312 1313 // Wake up 5 seconds later, the fatal handler may reset OnError or 1314 // ShowMessageBoxOnError when it is ready to abort. 1315 os::sleep(this, 5 * 1000, false); 1316 } 1317 } 1318 1319 PeriodicTask::real_time_tick(time_waited); 1320 } 1321 1322 // Signal that it is terminated 1323 { 1324 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1325 _watcher_thread = NULL; 1326 Terminator_lock->notify(); 1327 } 1328 1329 // Thread destructor usually does this.. 1330 ThreadLocalStorage::set_thread(NULL); 1331 } 1332 1333 void WatcherThread::start() { 1334 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1335 1336 if (watcher_thread() == NULL && _startable) { 1337 _should_terminate = false; 1338 // Create the single instance of WatcherThread 1339 new WatcherThread(); 1340 } 1341 } 1342 1343 void WatcherThread::make_startable() { 1344 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1345 _startable = true; 1346 } 1347 1348 void WatcherThread::stop() { 1349 // Get the PeriodicTask_lock if we can. If we cannot, then the 1350 // WatcherThread is using it and we don't want to block on that lock 1351 // here because that might cause a safepoint deadlock depending on 1352 // what the current WatcherThread tasks are doing. 1353 bool have_lock = PeriodicTask_lock->try_lock(); 1354 1355 _should_terminate = true; 1356 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1357 1358 if (have_lock) { 1359 WatcherThread* watcher = watcher_thread(); 1360 if (watcher != NULL) { 1361 // If we managed to get the lock, then we should unpark the 1362 // WatcherThread so that it can see we want it to stop. 1363 watcher->unpark(); 1364 } 1365 1366 PeriodicTask_lock->unlock(); 1367 } 1368 1369 // it is ok to take late safepoints here, if needed 1370 MutexLocker mu(Terminator_lock); 1371 1372 while (watcher_thread() != NULL) { 1373 // This wait should make safepoint checks, wait without a timeout, 1374 // and wait as a suspend-equivalent condition. 1375 // 1376 // Note: If the FlatProfiler is running, then this thread is waiting 1377 // for the WatcherThread to terminate and the WatcherThread, via the 1378 // FlatProfiler task, is waiting for the external suspend request on 1379 // this thread to complete. wait_for_ext_suspend_completion() will 1380 // eventually timeout, but that takes time. Making this wait a 1381 // suspend-equivalent condition solves that timeout problem. 1382 // 1383 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1384 Mutex::_as_suspend_equivalent_flag); 1385 } 1386 } 1387 1388 void WatcherThread::unpark() { 1389 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1390 PeriodicTask_lock->notify(); 1391 } 1392 1393 void WatcherThread::print_on(outputStream* st) const { 1394 st->print("\"%s\" ", name()); 1395 Thread::print_on(st); 1396 st->cr(); 1397 } 1398 1399 // ======= JavaThread ======== 1400 1401 // A JavaThread is a normal Java thread 1402 1403 void JavaThread::initialize() { 1404 // Initialize fields 1405 1406 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1407 set_claimed_par_id(UINT_MAX); 1408 1409 set_saved_exception_pc(NULL); 1410 set_threadObj(NULL); 1411 _anchor.clear(); 1412 set_entry_point(NULL); 1413 set_jni_functions(jni_functions()); 1414 set_callee_target(NULL); 1415 set_vm_result(NULL); 1416 set_vm_result_2(NULL); 1417 set_vframe_array_head(NULL); 1418 set_vframe_array_last(NULL); 1419 set_deferred_locals(NULL); 1420 set_deopt_mark(NULL); 1421 set_deopt_nmethod(NULL); 1422 clear_must_deopt_id(); 1423 set_monitor_chunks(NULL); 1424 set_next(NULL); 1425 set_thread_state(_thread_new); 1426 #if INCLUDE_NMT 1427 set_recorder(NULL); 1428 #endif 1429 _terminated = _not_terminated; 1430 _privileged_stack_top = NULL; 1431 _array_for_gc = NULL; 1432 _suspend_equivalent = false; 1433 _in_deopt_handler = 0; 1434 _doing_unsafe_access = false; 1435 _stack_guard_state = stack_guard_unused; 1436 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1437 _exception_pc = 0; 1438 _exception_handler_pc = 0; 1439 _is_method_handle_return = 0; 1440 _jvmti_thread_state= NULL; 1441 _should_post_on_exceptions_flag = JNI_FALSE; 1442 _jvmti_get_loaded_classes_closure = NULL; 1443 _interp_only_mode = 0; 1444 _special_runtime_exit_condition = _no_async_condition; 1445 _pending_async_exception = NULL; 1446 _thread_stat = NULL; 1447 _thread_stat = new ThreadStatistics(); 1448 _blocked_on_compilation = false; 1449 _jni_active_critical = 0; 1450 _pending_jni_exception_check_fn = NULL; 1451 _do_not_unlock_if_synchronized = false; 1452 _cached_monitor_info = NULL; 1453 _parker = Parker::Allocate(this); 1454 1455 #ifndef PRODUCT 1456 _jmp_ring_index = 0; 1457 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1458 record_jump(NULL, NULL, NULL, 0); 1459 } 1460 #endif /* PRODUCT */ 1461 1462 set_thread_profiler(NULL); 1463 if (FlatProfiler::is_active()) { 1464 // This is where we would decide to either give each thread it's own profiler 1465 // or use one global one from FlatProfiler, 1466 // or up to some count of the number of profiled threads, etc. 1467 ThreadProfiler* pp = new ThreadProfiler(); 1468 pp->engage(); 1469 set_thread_profiler(pp); 1470 } 1471 1472 // Setup safepoint state info for this thread 1473 ThreadSafepointState::create(this); 1474 1475 debug_only(_java_call_counter = 0); 1476 1477 // JVMTI PopFrame support 1478 _popframe_condition = popframe_inactive; 1479 _popframe_preserved_args = NULL; 1480 _popframe_preserved_args_size = 0; 1481 1482 pd_initialize(); 1483 } 1484 1485 #if INCLUDE_ALL_GCS 1486 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1487 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1488 #endif // INCLUDE_ALL_GCS 1489 1490 JavaThread::JavaThread(bool is_attaching_via_jni) : 1491 Thread() 1492 #if INCLUDE_ALL_GCS 1493 , _satb_mark_queue(&_satb_mark_queue_set), 1494 _dirty_card_queue(&_dirty_card_queue_set) 1495 #endif // INCLUDE_ALL_GCS 1496 { 1497 initialize(); 1498 if (is_attaching_via_jni) { 1499 _jni_attach_state = _attaching_via_jni; 1500 } else { 1501 _jni_attach_state = _not_attaching_via_jni; 1502 } 1503 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1504 _safepoint_visible = false; 1505 } 1506 1507 bool JavaThread::reguard_stack(address cur_sp) { 1508 if (_stack_guard_state != stack_guard_yellow_disabled) { 1509 return true; // Stack already guarded or guard pages not needed. 1510 } 1511 1512 if (register_stack_overflow()) { 1513 // For those architectures which have separate register and 1514 // memory stacks, we must check the register stack to see if 1515 // it has overflowed. 1516 return false; 1517 } 1518 1519 // Java code never executes within the yellow zone: the latter is only 1520 // there to provoke an exception during stack banging. If java code 1521 // is executing there, either StackShadowPages should be larger, or 1522 // some exception code in c1, c2 or the interpreter isn't unwinding 1523 // when it should. 1524 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1525 1526 enable_stack_yellow_zone(); 1527 return true; 1528 } 1529 1530 bool JavaThread::reguard_stack(void) { 1531 return reguard_stack(os::current_stack_pointer()); 1532 } 1533 1534 1535 void JavaThread::block_if_vm_exited() { 1536 if (_terminated == _vm_exited) { 1537 // _vm_exited is set at safepoint, and Threads_lock is never released 1538 // we will block here forever 1539 Threads_lock->lock_without_safepoint_check(); 1540 ShouldNotReachHere(); 1541 } 1542 } 1543 1544 1545 // Remove this ifdef when C1 is ported to the compiler interface. 1546 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1547 1548 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1549 Thread() 1550 #if INCLUDE_ALL_GCS 1551 , _satb_mark_queue(&_satb_mark_queue_set), 1552 _dirty_card_queue(&_dirty_card_queue_set) 1553 #endif // INCLUDE_ALL_GCS 1554 { 1555 if (TraceThreadEvents) { 1556 tty->print_cr("creating thread %p", this); 1557 } 1558 initialize(); 1559 _jni_attach_state = _not_attaching_via_jni; 1560 set_entry_point(entry_point); 1561 // Create the native thread itself. 1562 // %note runtime_23 1563 os::ThreadType thr_type = os::java_thread; 1564 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1565 os::java_thread; 1566 os::create_thread(this, thr_type, stack_sz); 1567 _safepoint_visible = false; 1568 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1569 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1570 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1571 // the exception consists of creating the exception object & initializing it, initialization 1572 // will leave the VM via a JavaCall and then all locks must be unlocked). 1573 // 1574 // The thread is still suspended when we reach here. Thread must be explicit started 1575 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1576 // by calling Threads:add. The reason why this is not done here, is because the thread 1577 // object must be fully initialized (take a look at JVM_Start) 1578 } 1579 1580 JavaThread::~JavaThread() { 1581 if (TraceThreadEvents) { 1582 tty->print_cr("terminate thread %p", this); 1583 } 1584 1585 // By now, this thread should already be invisible to safepoint, 1586 // and its per-thread recorder also collected. 1587 assert(!is_safepoint_visible(), "wrong state"); 1588 #if INCLUDE_NMT 1589 assert(get_recorder() == NULL, "Already collected"); 1590 #endif // INCLUDE_NMT 1591 1592 // JSR166 -- return the parker to the free list 1593 Parker::Release(_parker); 1594 _parker = NULL; 1595 1596 // Free any remaining previous UnrollBlock 1597 vframeArray* old_array = vframe_array_last(); 1598 1599 if (old_array != NULL) { 1600 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1601 old_array->set_unroll_block(NULL); 1602 delete old_info; 1603 delete old_array; 1604 } 1605 1606 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1607 if (deferred != NULL) { 1608 // This can only happen if thread is destroyed before deoptimization occurs. 1609 assert(deferred->length() != 0, "empty array!"); 1610 do { 1611 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1612 deferred->remove_at(0); 1613 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1614 delete dlv; 1615 } while (deferred->length() != 0); 1616 delete deferred; 1617 } 1618 1619 // All Java related clean up happens in exit 1620 ThreadSafepointState::destroy(this); 1621 if (_thread_profiler != NULL) delete _thread_profiler; 1622 if (_thread_stat != NULL) delete _thread_stat; 1623 } 1624 1625 1626 // The first routine called by a new Java thread 1627 void JavaThread::run() { 1628 // initialize thread-local alloc buffer related fields 1629 this->initialize_tlab(); 1630 1631 // used to test validity of stack trace backs 1632 this->record_base_of_stack_pointer(); 1633 1634 // Record real stack base and size. 1635 this->record_stack_base_and_size(); 1636 1637 // Initialize thread local storage; set before calling MutexLocker 1638 this->initialize_thread_local_storage(); 1639 1640 this->create_stack_guard_pages(); 1641 1642 this->cache_global_variables(); 1643 1644 // Thread is now sufficient initialized to be handled by the safepoint code as being 1645 // in the VM. Change thread state from _thread_new to _thread_in_vm 1646 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1647 1648 assert(JavaThread::current() == this, "sanity check"); 1649 assert(!Thread::current()->owns_locks(), "sanity check"); 1650 1651 DTRACE_THREAD_PROBE(start, this); 1652 1653 // This operation might block. We call that after all safepoint checks for a new thread has 1654 // been completed. 1655 this->set_active_handles(JNIHandleBlock::allocate_block()); 1656 1657 if (JvmtiExport::should_post_thread_life()) { 1658 JvmtiExport::post_thread_start(this); 1659 } 1660 1661 EventThreadStart event; 1662 if (event.should_commit()) { 1663 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1664 event.commit(); 1665 } 1666 1667 // We call another function to do the rest so we are sure that the stack addresses used 1668 // from there will be lower than the stack base just computed 1669 thread_main_inner(); 1670 1671 // Note, thread is no longer valid at this point! 1672 } 1673 1674 1675 void JavaThread::thread_main_inner() { 1676 assert(JavaThread::current() == this, "sanity check"); 1677 assert(this->threadObj() != NULL, "just checking"); 1678 1679 // Execute thread entry point unless this thread has a pending exception 1680 // or has been stopped before starting. 1681 // Note: Due to JVM_StopThread we can have pending exceptions already! 1682 if (!this->has_pending_exception() && 1683 !java_lang_Thread::is_stillborn(this->threadObj())) { 1684 { 1685 ResourceMark rm(this); 1686 this->set_native_thread_name(this->get_thread_name()); 1687 } 1688 HandleMark hm(this); 1689 this->entry_point()(this, this); 1690 } 1691 1692 DTRACE_THREAD_PROBE(stop, this); 1693 1694 this->exit(false); 1695 delete this; 1696 } 1697 1698 1699 static void ensure_join(JavaThread* thread) { 1700 // We do not need to grap the Threads_lock, since we are operating on ourself. 1701 Handle threadObj(thread, thread->threadObj()); 1702 assert(threadObj.not_null(), "java thread object must exist"); 1703 ObjectLocker lock(threadObj, thread); 1704 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1705 thread->clear_pending_exception(); 1706 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1707 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1708 // Clear the native thread instance - this makes isAlive return false and allows the join() 1709 // to complete once we've done the notify_all below 1710 java_lang_Thread::set_thread(threadObj(), NULL); 1711 lock.notify_all(thread); 1712 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1713 thread->clear_pending_exception(); 1714 } 1715 1716 1717 // For any new cleanup additions, please check to see if they need to be applied to 1718 // cleanup_failed_attach_current_thread as well. 1719 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1720 assert(this == JavaThread::current(), "thread consistency check"); 1721 1722 HandleMark hm(this); 1723 Handle uncaught_exception(this, this->pending_exception()); 1724 this->clear_pending_exception(); 1725 Handle threadObj(this, this->threadObj()); 1726 assert(threadObj.not_null(), "Java thread object should be created"); 1727 1728 if (get_thread_profiler() != NULL) { 1729 get_thread_profiler()->disengage(); 1730 ResourceMark rm; 1731 get_thread_profiler()->print(get_thread_name()); 1732 } 1733 1734 1735 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1736 { 1737 EXCEPTION_MARK; 1738 1739 CLEAR_PENDING_EXCEPTION; 1740 } 1741 if (!destroy_vm) { 1742 if (uncaught_exception.not_null()) { 1743 EXCEPTION_MARK; 1744 // Call method Thread.dispatchUncaughtException(). 1745 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1746 JavaValue result(T_VOID); 1747 JavaCalls::call_virtual(&result, 1748 threadObj, thread_klass, 1749 vmSymbols::dispatchUncaughtException_name(), 1750 vmSymbols::throwable_void_signature(), 1751 uncaught_exception, 1752 THREAD); 1753 if (HAS_PENDING_EXCEPTION) { 1754 ResourceMark rm(this); 1755 jio_fprintf(defaultStream::error_stream(), 1756 "\nException: %s thrown from the UncaughtExceptionHandler" 1757 " in thread \"%s\"\n", 1758 pending_exception()->klass()->external_name(), 1759 get_thread_name()); 1760 CLEAR_PENDING_EXCEPTION; 1761 } 1762 } 1763 1764 // Called before the java thread exit since we want to read info 1765 // from java_lang_Thread object 1766 EventThreadEnd event; 1767 if (event.should_commit()) { 1768 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1769 event.commit(); 1770 } 1771 1772 // Call after last event on thread 1773 EVENT_THREAD_EXIT(this); 1774 1775 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1776 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1777 // is deprecated anyhow. 1778 if (!is_Compiler_thread()) { 1779 int count = 3; 1780 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1781 EXCEPTION_MARK; 1782 JavaValue result(T_VOID); 1783 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1784 JavaCalls::call_virtual(&result, 1785 threadObj, thread_klass, 1786 vmSymbols::exit_method_name(), 1787 vmSymbols::void_method_signature(), 1788 THREAD); 1789 CLEAR_PENDING_EXCEPTION; 1790 } 1791 } 1792 // notify JVMTI 1793 if (JvmtiExport::should_post_thread_life()) { 1794 JvmtiExport::post_thread_end(this); 1795 } 1796 1797 // We have notified the agents that we are exiting, before we go on, 1798 // we must check for a pending external suspend request and honor it 1799 // in order to not surprise the thread that made the suspend request. 1800 while (true) { 1801 { 1802 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1803 if (!is_external_suspend()) { 1804 set_terminated(_thread_exiting); 1805 ThreadService::current_thread_exiting(this); 1806 break; 1807 } 1808 // Implied else: 1809 // Things get a little tricky here. We have a pending external 1810 // suspend request, but we are holding the SR_lock so we 1811 // can't just self-suspend. So we temporarily drop the lock 1812 // and then self-suspend. 1813 } 1814 1815 ThreadBlockInVM tbivm(this); 1816 java_suspend_self(); 1817 1818 // We're done with this suspend request, but we have to loop around 1819 // and check again. Eventually we will get SR_lock without a pending 1820 // external suspend request and will be able to mark ourselves as 1821 // exiting. 1822 } 1823 // no more external suspends are allowed at this point 1824 } else { 1825 // before_exit() has already posted JVMTI THREAD_END events 1826 } 1827 1828 // Notify waiters on thread object. This has to be done after exit() is called 1829 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1830 // group should have the destroyed bit set before waiters are notified). 1831 ensure_join(this); 1832 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1833 1834 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1835 // held by this thread must be released. A detach operation must only 1836 // get here if there are no Java frames on the stack. Therefore, any 1837 // owned monitors at this point MUST be JNI-acquired monitors which are 1838 // pre-inflated and in the monitor cache. 1839 // 1840 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1841 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1842 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1843 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1844 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1845 } 1846 1847 // These things needs to be done while we are still a Java Thread. Make sure that thread 1848 // is in a consistent state, in case GC happens 1849 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1850 1851 if (active_handles() != NULL) { 1852 JNIHandleBlock* block = active_handles(); 1853 set_active_handles(NULL); 1854 JNIHandleBlock::release_block(block); 1855 } 1856 1857 if (free_handle_block() != NULL) { 1858 JNIHandleBlock* block = free_handle_block(); 1859 set_free_handle_block(NULL); 1860 JNIHandleBlock::release_block(block); 1861 } 1862 1863 // These have to be removed while this is still a valid thread. 1864 remove_stack_guard_pages(); 1865 1866 if (UseTLAB) { 1867 tlab().make_parsable(true); // retire TLAB 1868 } 1869 1870 if (JvmtiEnv::environments_might_exist()) { 1871 JvmtiExport::cleanup_thread(this); 1872 } 1873 1874 // We must flush any deferred card marks before removing a thread from 1875 // the list of active threads. 1876 Universe::heap()->flush_deferred_store_barrier(this); 1877 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1878 1879 #if INCLUDE_ALL_GCS 1880 // We must flush the G1-related buffers before removing a thread 1881 // from the list of active threads. We must do this after any deferred 1882 // card marks have been flushed (above) so that any entries that are 1883 // added to the thread's dirty card queue as a result are not lost. 1884 if (UseG1GC) { 1885 flush_barrier_queues(); 1886 } 1887 #endif // INCLUDE_ALL_GCS 1888 1889 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1890 Threads::remove(this); 1891 } 1892 1893 #if INCLUDE_ALL_GCS 1894 // Flush G1-related queues. 1895 void JavaThread::flush_barrier_queues() { 1896 satb_mark_queue().flush(); 1897 dirty_card_queue().flush(); 1898 } 1899 1900 void JavaThread::initialize_queues() { 1901 assert(!SafepointSynchronize::is_at_safepoint(), 1902 "we should not be at a safepoint"); 1903 1904 ObjPtrQueue& satb_queue = satb_mark_queue(); 1905 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1906 // The SATB queue should have been constructed with its active 1907 // field set to false. 1908 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1909 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1910 // If we are creating the thread during a marking cycle, we should 1911 // set the active field of the SATB queue to true. 1912 if (satb_queue_set.is_active()) { 1913 satb_queue.set_active(true); 1914 } 1915 1916 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1917 // The dirty card queue should have been constructed with its 1918 // active field set to true. 1919 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1920 } 1921 #endif // INCLUDE_ALL_GCS 1922 1923 void JavaThread::cleanup_failed_attach_current_thread() { 1924 if (get_thread_profiler() != NULL) { 1925 get_thread_profiler()->disengage(); 1926 ResourceMark rm; 1927 get_thread_profiler()->print(get_thread_name()); 1928 } 1929 1930 if (active_handles() != NULL) { 1931 JNIHandleBlock* block = active_handles(); 1932 set_active_handles(NULL); 1933 JNIHandleBlock::release_block(block); 1934 } 1935 1936 if (free_handle_block() != NULL) { 1937 JNIHandleBlock* block = free_handle_block(); 1938 set_free_handle_block(NULL); 1939 JNIHandleBlock::release_block(block); 1940 } 1941 1942 // These have to be removed while this is still a valid thread. 1943 remove_stack_guard_pages(); 1944 1945 if (UseTLAB) { 1946 tlab().make_parsable(true); // retire TLAB, if any 1947 } 1948 1949 #if INCLUDE_ALL_GCS 1950 if (UseG1GC) { 1951 flush_barrier_queues(); 1952 } 1953 #endif // INCLUDE_ALL_GCS 1954 1955 Threads::remove(this); 1956 delete this; 1957 } 1958 1959 1960 1961 1962 JavaThread* JavaThread::active() { 1963 Thread* thread = ThreadLocalStorage::thread(); 1964 assert(thread != NULL, "just checking"); 1965 if (thread->is_Java_thread()) { 1966 return (JavaThread*) thread; 1967 } else { 1968 assert(thread->is_VM_thread(), "this must be a vm thread"); 1969 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1970 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1971 assert(ret->is_Java_thread(), "must be a Java thread"); 1972 return ret; 1973 } 1974 } 1975 1976 bool JavaThread::is_lock_owned(address adr) const { 1977 if (Thread::is_lock_owned(adr)) return true; 1978 1979 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1980 if (chunk->contains(adr)) return true; 1981 } 1982 1983 return false; 1984 } 1985 1986 1987 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1988 chunk->set_next(monitor_chunks()); 1989 set_monitor_chunks(chunk); 1990 } 1991 1992 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1993 guarantee(monitor_chunks() != NULL, "must be non empty"); 1994 if (monitor_chunks() == chunk) { 1995 set_monitor_chunks(chunk->next()); 1996 } else { 1997 MonitorChunk* prev = monitor_chunks(); 1998 while (prev->next() != chunk) prev = prev->next(); 1999 prev->set_next(chunk->next()); 2000 } 2001 } 2002 2003 // JVM support. 2004 2005 // Note: this function shouldn't block if it's called in 2006 // _thread_in_native_trans state (such as from 2007 // check_special_condition_for_native_trans()). 2008 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2009 2010 if (has_last_Java_frame() && has_async_condition()) { 2011 // If we are at a polling page safepoint (not a poll return) 2012 // then we must defer async exception because live registers 2013 // will be clobbered by the exception path. Poll return is 2014 // ok because the call we a returning from already collides 2015 // with exception handling registers and so there is no issue. 2016 // (The exception handling path kills call result registers but 2017 // this is ok since the exception kills the result anyway). 2018 2019 if (is_at_poll_safepoint()) { 2020 // if the code we are returning to has deoptimized we must defer 2021 // the exception otherwise live registers get clobbered on the 2022 // exception path before deoptimization is able to retrieve them. 2023 // 2024 RegisterMap map(this, false); 2025 frame caller_fr = last_frame().sender(&map); 2026 assert(caller_fr.is_compiled_frame(), "what?"); 2027 if (caller_fr.is_deoptimized_frame()) { 2028 if (TraceExceptions) { 2029 ResourceMark rm; 2030 tty->print_cr("deferred async exception at compiled safepoint"); 2031 } 2032 return; 2033 } 2034 } 2035 } 2036 2037 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2038 if (condition == _no_async_condition) { 2039 // Conditions have changed since has_special_runtime_exit_condition() 2040 // was called: 2041 // - if we were here only because of an external suspend request, 2042 // then that was taken care of above (or cancelled) so we are done 2043 // - if we were here because of another async request, then it has 2044 // been cleared between the has_special_runtime_exit_condition() 2045 // and now so again we are done 2046 return; 2047 } 2048 2049 // Check for pending async. exception 2050 if (_pending_async_exception != NULL) { 2051 // Only overwrite an already pending exception, if it is not a threadDeath. 2052 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2053 2054 // We cannot call Exceptions::_throw(...) here because we cannot block 2055 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2056 2057 if (TraceExceptions) { 2058 ResourceMark rm; 2059 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2060 if (has_last_Java_frame()) { 2061 frame f = last_frame(); 2062 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2063 } 2064 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2065 } 2066 _pending_async_exception = NULL; 2067 clear_has_async_exception(); 2068 } 2069 } 2070 2071 if (check_unsafe_error && 2072 condition == _async_unsafe_access_error && !has_pending_exception()) { 2073 condition = _no_async_condition; // done 2074 switch (thread_state()) { 2075 case _thread_in_vm: 2076 { 2077 JavaThread* THREAD = this; 2078 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2079 } 2080 case _thread_in_native: 2081 { 2082 ThreadInVMfromNative tiv(this); 2083 JavaThread* THREAD = this; 2084 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2085 } 2086 case _thread_in_Java: 2087 { 2088 ThreadInVMfromJava tiv(this); 2089 JavaThread* THREAD = this; 2090 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2091 } 2092 default: 2093 ShouldNotReachHere(); 2094 } 2095 } 2096 2097 assert(condition == _no_async_condition || has_pending_exception() || 2098 (!check_unsafe_error && condition == _async_unsafe_access_error), 2099 "must have handled the async condition, if no exception"); 2100 } 2101 2102 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2103 // 2104 // Check for pending external suspend. Internal suspend requests do 2105 // not use handle_special_runtime_exit_condition(). 2106 // If JNIEnv proxies are allowed, don't self-suspend if the target 2107 // thread is not the current thread. In older versions of jdbx, jdbx 2108 // threads could call into the VM with another thread's JNIEnv so we 2109 // can be here operating on behalf of a suspended thread (4432884). 2110 bool do_self_suspend = is_external_suspend_with_lock(); 2111 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2112 // 2113 // Because thread is external suspended the safepoint code will count 2114 // thread as at a safepoint. This can be odd because we can be here 2115 // as _thread_in_Java which would normally transition to _thread_blocked 2116 // at a safepoint. We would like to mark the thread as _thread_blocked 2117 // before calling java_suspend_self like all other callers of it but 2118 // we must then observe proper safepoint protocol. (We can't leave 2119 // _thread_blocked with a safepoint in progress). However we can be 2120 // here as _thread_in_native_trans so we can't use a normal transition 2121 // constructor/destructor pair because they assert on that type of 2122 // transition. We could do something like: 2123 // 2124 // JavaThreadState state = thread_state(); 2125 // set_thread_state(_thread_in_vm); 2126 // { 2127 // ThreadBlockInVM tbivm(this); 2128 // java_suspend_self() 2129 // } 2130 // set_thread_state(_thread_in_vm_trans); 2131 // if (safepoint) block; 2132 // set_thread_state(state); 2133 // 2134 // but that is pretty messy. Instead we just go with the way the 2135 // code has worked before and note that this is the only path to 2136 // java_suspend_self that doesn't put the thread in _thread_blocked 2137 // mode. 2138 2139 frame_anchor()->make_walkable(this); 2140 java_suspend_self(); 2141 2142 // We might be here for reasons in addition to the self-suspend request 2143 // so check for other async requests. 2144 } 2145 2146 if (check_asyncs) { 2147 check_and_handle_async_exceptions(); 2148 } 2149 } 2150 2151 void JavaThread::send_thread_stop(oop java_throwable) { 2152 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2153 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2154 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2155 2156 // Do not throw asynchronous exceptions against the compiler thread 2157 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2158 if (is_Compiler_thread()) return; 2159 2160 { 2161 // Actually throw the Throwable against the target Thread - however 2162 // only if there is no thread death exception installed already. 2163 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2164 // If the topmost frame is a runtime stub, then we are calling into 2165 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2166 // must deoptimize the caller before continuing, as the compiled exception handler table 2167 // may not be valid 2168 if (has_last_Java_frame()) { 2169 frame f = last_frame(); 2170 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2171 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2172 RegisterMap reg_map(this, UseBiasedLocking); 2173 frame compiled_frame = f.sender(®_map); 2174 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2175 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2176 } 2177 } 2178 } 2179 2180 // Set async. pending exception in thread. 2181 set_pending_async_exception(java_throwable); 2182 2183 if (TraceExceptions) { 2184 ResourceMark rm; 2185 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2186 } 2187 // for AbortVMOnException flag 2188 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2189 } 2190 } 2191 2192 2193 // Interrupt thread so it will wake up from a potential wait() 2194 Thread::interrupt(this); 2195 } 2196 2197 // External suspension mechanism. 2198 // 2199 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2200 // to any VM_locks and it is at a transition 2201 // Self-suspension will happen on the transition out of the vm. 2202 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2203 // 2204 // Guarantees on return: 2205 // + Target thread will not execute any new bytecode (that's why we need to 2206 // force a safepoint) 2207 // + Target thread will not enter any new monitors 2208 // 2209 void JavaThread::java_suspend() { 2210 { MutexLocker mu(Threads_lock); 2211 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2212 return; 2213 } 2214 } 2215 2216 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2217 if (!is_external_suspend()) { 2218 // a racing resume has cancelled us; bail out now 2219 return; 2220 } 2221 2222 // suspend is done 2223 uint32_t debug_bits = 0; 2224 // Warning: is_ext_suspend_completed() may temporarily drop the 2225 // SR_lock to allow the thread to reach a stable thread state if 2226 // it is currently in a transient thread state. 2227 if (is_ext_suspend_completed(false /* !called_by_wait */, 2228 SuspendRetryDelay, &debug_bits) ) { 2229 return; 2230 } 2231 } 2232 2233 VM_ForceSafepoint vm_suspend; 2234 VMThread::execute(&vm_suspend); 2235 } 2236 2237 // Part II of external suspension. 2238 // A JavaThread self suspends when it detects a pending external suspend 2239 // request. This is usually on transitions. It is also done in places 2240 // where continuing to the next transition would surprise the caller, 2241 // e.g., monitor entry. 2242 // 2243 // Returns the number of times that the thread self-suspended. 2244 // 2245 // Note: DO NOT call java_suspend_self() when you just want to block current 2246 // thread. java_suspend_self() is the second stage of cooperative 2247 // suspension for external suspend requests and should only be used 2248 // to complete an external suspend request. 2249 // 2250 int JavaThread::java_suspend_self() { 2251 int ret = 0; 2252 2253 // we are in the process of exiting so don't suspend 2254 if (is_exiting()) { 2255 clear_external_suspend(); 2256 return ret; 2257 } 2258 2259 assert(_anchor.walkable() || 2260 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2261 "must have walkable stack"); 2262 2263 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2264 2265 assert(!this->is_ext_suspended(), 2266 "a thread trying to self-suspend should not already be suspended"); 2267 2268 if (this->is_suspend_equivalent()) { 2269 // If we are self-suspending as a result of the lifting of a 2270 // suspend equivalent condition, then the suspend_equivalent 2271 // flag is not cleared until we set the ext_suspended flag so 2272 // that wait_for_ext_suspend_completion() returns consistent 2273 // results. 2274 this->clear_suspend_equivalent(); 2275 } 2276 2277 // A racing resume may have cancelled us before we grabbed SR_lock 2278 // above. Or another external suspend request could be waiting for us 2279 // by the time we return from SR_lock()->wait(). The thread 2280 // that requested the suspension may already be trying to walk our 2281 // stack and if we return now, we can change the stack out from under 2282 // it. This would be a "bad thing (TM)" and cause the stack walker 2283 // to crash. We stay self-suspended until there are no more pending 2284 // external suspend requests. 2285 while (is_external_suspend()) { 2286 ret++; 2287 this->set_ext_suspended(); 2288 2289 // _ext_suspended flag is cleared by java_resume() 2290 while (is_ext_suspended()) { 2291 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2292 } 2293 } 2294 2295 return ret; 2296 } 2297 2298 #ifdef ASSERT 2299 // verify the JavaThread has not yet been published in the Threads::list, and 2300 // hence doesn't need protection from concurrent access at this stage 2301 void JavaThread::verify_not_published() { 2302 if (!Threads_lock->owned_by_self()) { 2303 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2304 assert(!Threads::includes(this), 2305 "java thread shouldn't have been published yet!"); 2306 } 2307 else { 2308 assert(!Threads::includes(this), 2309 "java thread shouldn't have been published yet!"); 2310 } 2311 } 2312 #endif 2313 2314 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2315 // progress or when _suspend_flags is non-zero. 2316 // Current thread needs to self-suspend if there is a suspend request and/or 2317 // block if a safepoint is in progress. 2318 // Async exception ISN'T checked. 2319 // Note only the ThreadInVMfromNative transition can call this function 2320 // directly and when thread state is _thread_in_native_trans 2321 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2322 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2323 2324 JavaThread *curJT = JavaThread::current(); 2325 bool do_self_suspend = thread->is_external_suspend(); 2326 2327 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2328 2329 // If JNIEnv proxies are allowed, don't self-suspend if the target 2330 // thread is not the current thread. In older versions of jdbx, jdbx 2331 // threads could call into the VM with another thread's JNIEnv so we 2332 // can be here operating on behalf of a suspended thread (4432884). 2333 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2334 JavaThreadState state = thread->thread_state(); 2335 2336 // We mark this thread_blocked state as a suspend-equivalent so 2337 // that a caller to is_ext_suspend_completed() won't be confused. 2338 // The suspend-equivalent state is cleared by java_suspend_self(). 2339 thread->set_suspend_equivalent(); 2340 2341 // If the safepoint code sees the _thread_in_native_trans state, it will 2342 // wait until the thread changes to other thread state. There is no 2343 // guarantee on how soon we can obtain the SR_lock and complete the 2344 // self-suspend request. It would be a bad idea to let safepoint wait for 2345 // too long. Temporarily change the state to _thread_blocked to 2346 // let the VM thread know that this thread is ready for GC. The problem 2347 // of changing thread state is that safepoint could happen just after 2348 // java_suspend_self() returns after being resumed, and VM thread will 2349 // see the _thread_blocked state. We must check for safepoint 2350 // after restoring the state and make sure we won't leave while a safepoint 2351 // is in progress. 2352 thread->set_thread_state(_thread_blocked); 2353 thread->java_suspend_self(); 2354 thread->set_thread_state(state); 2355 // Make sure new state is seen by VM thread 2356 if (os::is_MP()) { 2357 if (UseMembar) { 2358 // Force a fence between the write above and read below 2359 OrderAccess::fence(); 2360 } else { 2361 // Must use this rather than serialization page in particular on Windows 2362 InterfaceSupport::serialize_memory(thread); 2363 } 2364 } 2365 } 2366 2367 if (SafepointSynchronize::do_call_back()) { 2368 // If we are safepointing, then block the caller which may not be 2369 // the same as the target thread (see above). 2370 SafepointSynchronize::block(curJT); 2371 } 2372 2373 if (thread->is_deopt_suspend()) { 2374 thread->clear_deopt_suspend(); 2375 RegisterMap map(thread, false); 2376 frame f = thread->last_frame(); 2377 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2378 f = f.sender(&map); 2379 } 2380 if (f.id() == thread->must_deopt_id()) { 2381 thread->clear_must_deopt_id(); 2382 f.deoptimize(thread); 2383 } else { 2384 fatal("missed deoptimization!"); 2385 } 2386 } 2387 } 2388 2389 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2390 // progress or when _suspend_flags is non-zero. 2391 // Current thread needs to self-suspend if there is a suspend request and/or 2392 // block if a safepoint is in progress. 2393 // Also check for pending async exception (not including unsafe access error). 2394 // Note only the native==>VM/Java barriers can call this function and when 2395 // thread state is _thread_in_native_trans. 2396 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2397 check_safepoint_and_suspend_for_native_trans(thread); 2398 2399 if (thread->has_async_exception()) { 2400 // We are in _thread_in_native_trans state, don't handle unsafe 2401 // access error since that may block. 2402 thread->check_and_handle_async_exceptions(false); 2403 } 2404 } 2405 2406 // This is a variant of the normal 2407 // check_special_condition_for_native_trans with slightly different 2408 // semantics for use by critical native wrappers. It does all the 2409 // normal checks but also performs the transition back into 2410 // thread_in_Java state. This is required so that critical natives 2411 // can potentially block and perform a GC if they are the last thread 2412 // exiting the GC_locker. 2413 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2414 check_special_condition_for_native_trans(thread); 2415 2416 // Finish the transition 2417 thread->set_thread_state(_thread_in_Java); 2418 2419 if (thread->do_critical_native_unlock()) { 2420 ThreadInVMfromJavaNoAsyncException tiv(thread); 2421 GC_locker::unlock_critical(thread); 2422 thread->clear_critical_native_unlock(); 2423 } 2424 } 2425 2426 // We need to guarantee the Threads_lock here, since resumes are not 2427 // allowed during safepoint synchronization 2428 // Can only resume from an external suspension 2429 void JavaThread::java_resume() { 2430 assert_locked_or_safepoint(Threads_lock); 2431 2432 // Sanity check: thread is gone, has started exiting or the thread 2433 // was not externally suspended. 2434 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2435 return; 2436 } 2437 2438 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2439 2440 clear_external_suspend(); 2441 2442 if (is_ext_suspended()) { 2443 clear_ext_suspended(); 2444 SR_lock()->notify_all(); 2445 } 2446 } 2447 2448 void JavaThread::create_stack_guard_pages() { 2449 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2450 address low_addr = stack_base() - stack_size(); 2451 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2452 2453 int allocate = os::allocate_stack_guard_pages(); 2454 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2455 2456 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2457 warning("Attempt to allocate stack guard pages failed."); 2458 return; 2459 } 2460 2461 if (os::guard_memory((char *) low_addr, len)) { 2462 _stack_guard_state = stack_guard_enabled; 2463 } else { 2464 warning("Attempt to protect stack guard pages failed."); 2465 if (os::uncommit_memory((char *) low_addr, len)) { 2466 warning("Attempt to deallocate stack guard pages failed."); 2467 } 2468 } 2469 } 2470 2471 void JavaThread::remove_stack_guard_pages() { 2472 assert(Thread::current() == this, "from different thread"); 2473 if (_stack_guard_state == stack_guard_unused) return; 2474 address low_addr = stack_base() - stack_size(); 2475 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2476 2477 if (os::allocate_stack_guard_pages()) { 2478 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2479 _stack_guard_state = stack_guard_unused; 2480 } else { 2481 warning("Attempt to deallocate stack guard pages failed."); 2482 } 2483 } else { 2484 if (_stack_guard_state == stack_guard_unused) return; 2485 if (os::unguard_memory((char *) low_addr, len)) { 2486 _stack_guard_state = stack_guard_unused; 2487 } else { 2488 warning("Attempt to unprotect stack guard pages failed."); 2489 } 2490 } 2491 } 2492 2493 void JavaThread::enable_stack_yellow_zone() { 2494 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2495 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2496 2497 // The base notation is from the stacks point of view, growing downward. 2498 // We need to adjust it to work correctly with guard_memory() 2499 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2500 2501 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2502 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2503 2504 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2505 _stack_guard_state = stack_guard_enabled; 2506 } else { 2507 warning("Attempt to guard stack yellow zone failed."); 2508 } 2509 enable_register_stack_guard(); 2510 } 2511 2512 void JavaThread::disable_stack_yellow_zone() { 2513 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2514 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2515 2516 // Simply return if called for a thread that does not use guard pages. 2517 if (_stack_guard_state == stack_guard_unused) return; 2518 2519 // The base notation is from the stacks point of view, growing downward. 2520 // We need to adjust it to work correctly with guard_memory() 2521 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2522 2523 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2524 _stack_guard_state = stack_guard_yellow_disabled; 2525 } else { 2526 warning("Attempt to unguard stack yellow zone failed."); 2527 } 2528 disable_register_stack_guard(); 2529 } 2530 2531 void JavaThread::enable_stack_red_zone() { 2532 // The base notation is from the stacks point of view, growing downward. 2533 // We need to adjust it to work correctly with guard_memory() 2534 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2535 address base = stack_red_zone_base() - stack_red_zone_size(); 2536 2537 guarantee(base < stack_base(), "Error calculating stack red zone"); 2538 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2539 2540 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2541 warning("Attempt to guard stack red zone failed."); 2542 } 2543 } 2544 2545 void JavaThread::disable_stack_red_zone() { 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 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2549 address base = stack_red_zone_base() - stack_red_zone_size(); 2550 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2551 warning("Attempt to unguard stack red zone failed."); 2552 } 2553 } 2554 2555 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2556 // ignore is there is no stack 2557 if (!has_last_Java_frame()) return; 2558 // traverse the stack frames. Starts from top frame. 2559 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2560 frame* fr = fst.current(); 2561 f(fr, fst.register_map()); 2562 } 2563 } 2564 2565 2566 #ifndef PRODUCT 2567 // Deoptimization 2568 // Function for testing deoptimization 2569 void JavaThread::deoptimize() { 2570 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2571 StackFrameStream fst(this, UseBiasedLocking); 2572 bool deopt = false; // Dump stack only if a deopt actually happens. 2573 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2574 // Iterate over all frames in the thread and deoptimize 2575 for (; !fst.is_done(); fst.next()) { 2576 if (fst.current()->can_be_deoptimized()) { 2577 2578 if (only_at) { 2579 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2580 // consists of comma or carriage return separated numbers so 2581 // search for the current bci in that string. 2582 address pc = fst.current()->pc(); 2583 nmethod* nm = (nmethod*) fst.current()->cb(); 2584 ScopeDesc* sd = nm->scope_desc_at( pc); 2585 char buffer[8]; 2586 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2587 size_t len = strlen(buffer); 2588 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2589 while (found != NULL) { 2590 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2591 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2592 // Check that the bci found is bracketed by terminators. 2593 break; 2594 } 2595 found = strstr(found + 1, buffer); 2596 } 2597 if (!found) { 2598 continue; 2599 } 2600 } 2601 2602 if (DebugDeoptimization && !deopt) { 2603 deopt = true; // One-time only print before deopt 2604 tty->print_cr("[BEFORE Deoptimization]"); 2605 trace_frames(); 2606 trace_stack(); 2607 } 2608 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2609 } 2610 } 2611 2612 if (DebugDeoptimization && deopt) { 2613 tty->print_cr("[AFTER Deoptimization]"); 2614 trace_frames(); 2615 } 2616 } 2617 2618 2619 // Make zombies 2620 void JavaThread::make_zombies() { 2621 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2622 if (fst.current()->can_be_deoptimized()) { 2623 // it is a Java nmethod 2624 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2625 nm->make_not_entrant(); 2626 } 2627 } 2628 } 2629 #endif // PRODUCT 2630 2631 2632 void JavaThread::deoptimized_wrt_marked_nmethods() { 2633 if (!has_last_Java_frame()) return; 2634 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2635 StackFrameStream fst(this, UseBiasedLocking); 2636 for (; !fst.is_done(); fst.next()) { 2637 if (fst.current()->should_be_deoptimized()) { 2638 if (LogCompilation && xtty != NULL) { 2639 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2640 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2641 this->name(), nm != NULL ? nm->compile_id() : -1); 2642 } 2643 2644 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2645 } 2646 } 2647 } 2648 2649 2650 // If the caller is a NamedThread, then remember, in the current scope, 2651 // the given JavaThread in its _processed_thread field. 2652 class RememberProcessedThread: public StackObj { 2653 NamedThread* _cur_thr; 2654 public: 2655 RememberProcessedThread(JavaThread* jthr) { 2656 Thread* thread = Thread::current(); 2657 if (thread->is_Named_thread()) { 2658 _cur_thr = (NamedThread *)thread; 2659 _cur_thr->set_processed_thread(jthr); 2660 } else { 2661 _cur_thr = NULL; 2662 } 2663 } 2664 2665 ~RememberProcessedThread() { 2666 if (_cur_thr) { 2667 _cur_thr->set_processed_thread(NULL); 2668 } 2669 } 2670 }; 2671 2672 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2673 // Verify that the deferred card marks have been flushed. 2674 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2675 2676 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2677 // since there may be more than one thread using each ThreadProfiler. 2678 2679 // Traverse the GCHandles 2680 Thread::oops_do(f, cld_f, cf); 2681 2682 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2683 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2684 2685 if (has_last_Java_frame()) { 2686 // Record JavaThread to GC thread 2687 RememberProcessedThread rpt(this); 2688 2689 // Traverse the privileged stack 2690 if (_privileged_stack_top != NULL) { 2691 _privileged_stack_top->oops_do(f); 2692 } 2693 2694 // traverse the registered growable array 2695 if (_array_for_gc != NULL) { 2696 for (int index = 0; index < _array_for_gc->length(); index++) { 2697 f->do_oop(_array_for_gc->adr_at(index)); 2698 } 2699 } 2700 2701 // Traverse the monitor chunks 2702 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2703 chunk->oops_do(f); 2704 } 2705 2706 // Traverse the execution stack 2707 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2708 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2709 } 2710 } 2711 2712 // callee_target is never live across a gc point so NULL it here should 2713 // it still contain a methdOop. 2714 2715 set_callee_target(NULL); 2716 2717 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2718 // If we have deferred set_locals there might be oops waiting to be 2719 // written 2720 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2721 if (list != NULL) { 2722 for (int i = 0; i < list->length(); i++) { 2723 list->at(i)->oops_do(f); 2724 } 2725 } 2726 2727 // Traverse instance variables at the end since the GC may be moving things 2728 // around using this function 2729 f->do_oop((oop*) &_threadObj); 2730 f->do_oop((oop*) &_vm_result); 2731 f->do_oop((oop*) &_exception_oop); 2732 f->do_oop((oop*) &_pending_async_exception); 2733 2734 if (jvmti_thread_state() != NULL) { 2735 jvmti_thread_state()->oops_do(f); 2736 } 2737 } 2738 2739 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2740 Thread::nmethods_do(cf); // (super method is a no-op) 2741 2742 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2743 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2744 2745 if (has_last_Java_frame()) { 2746 // Traverse the execution stack 2747 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2748 fst.current()->nmethods_do(cf); 2749 } 2750 } 2751 } 2752 2753 void JavaThread::metadata_do(void f(Metadata*)) { 2754 Thread::metadata_do(f); 2755 if (has_last_Java_frame()) { 2756 // Traverse the execution stack to call f() on the methods in the stack 2757 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2758 fst.current()->metadata_do(f); 2759 } 2760 } else if (is_Compiler_thread()) { 2761 // need to walk ciMetadata in current compile tasks to keep alive. 2762 CompilerThread* ct = (CompilerThread*)this; 2763 if (ct->env() != NULL) { 2764 ct->env()->metadata_do(f); 2765 } 2766 } 2767 } 2768 2769 // Printing 2770 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2771 switch (_thread_state) { 2772 case _thread_uninitialized: return "_thread_uninitialized"; 2773 case _thread_new: return "_thread_new"; 2774 case _thread_new_trans: return "_thread_new_trans"; 2775 case _thread_in_native: return "_thread_in_native"; 2776 case _thread_in_native_trans: return "_thread_in_native_trans"; 2777 case _thread_in_vm: return "_thread_in_vm"; 2778 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2779 case _thread_in_Java: return "_thread_in_Java"; 2780 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2781 case _thread_blocked: return "_thread_blocked"; 2782 case _thread_blocked_trans: return "_thread_blocked_trans"; 2783 default: return "unknown thread state"; 2784 } 2785 } 2786 2787 #ifndef PRODUCT 2788 void JavaThread::print_thread_state_on(outputStream *st) const { 2789 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2790 }; 2791 void JavaThread::print_thread_state() const { 2792 print_thread_state_on(tty); 2793 }; 2794 #endif // PRODUCT 2795 2796 // Called by Threads::print() for VM_PrintThreads operation 2797 void JavaThread::print_on(outputStream *st) const { 2798 st->print("\"%s\" ", get_thread_name()); 2799 oop thread_oop = threadObj(); 2800 if (thread_oop != NULL) { 2801 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2802 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2803 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2804 } 2805 Thread::print_on(st); 2806 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2807 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2808 if (thread_oop != NULL) { 2809 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2810 } 2811 #ifndef PRODUCT 2812 print_thread_state_on(st); 2813 _safepoint_state->print_on(st); 2814 #endif // PRODUCT 2815 } 2816 2817 // Called by fatal error handler. The difference between this and 2818 // JavaThread::print() is that we can't grab lock or allocate memory. 2819 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2820 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2821 oop thread_obj = threadObj(); 2822 if (thread_obj != NULL) { 2823 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2824 } 2825 st->print(" ["); 2826 st->print("%s", _get_thread_state_name(_thread_state)); 2827 if (osthread()) { 2828 st->print(", id=%d", osthread()->thread_id()); 2829 } 2830 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2831 _stack_base - _stack_size, _stack_base); 2832 st->print("]"); 2833 return; 2834 } 2835 2836 // Verification 2837 2838 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2839 2840 void JavaThread::verify() { 2841 // Verify oops in the thread. 2842 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2843 2844 // Verify the stack frames. 2845 frames_do(frame_verify); 2846 } 2847 2848 // CR 6300358 (sub-CR 2137150) 2849 // Most callers of this method assume that it can't return NULL but a 2850 // thread may not have a name whilst it is in the process of attaching to 2851 // the VM - see CR 6412693, and there are places where a JavaThread can be 2852 // seen prior to having it's threadObj set (eg JNI attaching threads and 2853 // if vm exit occurs during initialization). These cases can all be accounted 2854 // for such that this method never returns NULL. 2855 const char* JavaThread::get_thread_name() const { 2856 #ifdef ASSERT 2857 // early safepoints can hit while current thread does not yet have TLS 2858 if (!SafepointSynchronize::is_at_safepoint()) { 2859 Thread *cur = Thread::current(); 2860 if (!(cur->is_Java_thread() && cur == this)) { 2861 // Current JavaThreads are allowed to get their own name without 2862 // the Threads_lock. 2863 assert_locked_or_safepoint(Threads_lock); 2864 } 2865 } 2866 #endif // ASSERT 2867 return get_thread_name_string(); 2868 } 2869 2870 // Returns a non-NULL representation of this thread's name, or a suitable 2871 // descriptive string if there is no set name 2872 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2873 const char* name_str; 2874 oop thread_obj = threadObj(); 2875 if (thread_obj != NULL) { 2876 typeArrayOop name = java_lang_Thread::name(thread_obj); 2877 if (name != NULL) { 2878 if (buf == NULL) { 2879 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2880 } 2881 else { 2882 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2883 } 2884 } 2885 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2886 name_str = "<no-name - thread is attaching>"; 2887 } 2888 else { 2889 name_str = Thread::name(); 2890 } 2891 } 2892 else { 2893 name_str = Thread::name(); 2894 } 2895 assert(name_str != NULL, "unexpected NULL thread name"); 2896 return name_str; 2897 } 2898 2899 2900 const char* JavaThread::get_threadgroup_name() const { 2901 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2902 oop thread_obj = threadObj(); 2903 if (thread_obj != NULL) { 2904 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2905 if (thread_group != NULL) { 2906 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2907 // ThreadGroup.name can be null 2908 if (name != NULL) { 2909 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2910 return str; 2911 } 2912 } 2913 } 2914 return NULL; 2915 } 2916 2917 const char* JavaThread::get_parent_name() const { 2918 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2919 oop thread_obj = threadObj(); 2920 if (thread_obj != NULL) { 2921 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2922 if (thread_group != NULL) { 2923 oop parent = java_lang_ThreadGroup::parent(thread_group); 2924 if (parent != NULL) { 2925 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2926 // ThreadGroup.name can be null 2927 if (name != NULL) { 2928 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2929 return str; 2930 } 2931 } 2932 } 2933 } 2934 return NULL; 2935 } 2936 2937 ThreadPriority JavaThread::java_priority() const { 2938 oop thr_oop = threadObj(); 2939 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2940 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2941 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2942 return priority; 2943 } 2944 2945 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2946 2947 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2948 // Link Java Thread object <-> C++ Thread 2949 2950 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2951 // and put it into a new Handle. The Handle "thread_oop" can then 2952 // be used to pass the C++ thread object to other methods. 2953 2954 // Set the Java level thread object (jthread) field of the 2955 // new thread (a JavaThread *) to C++ thread object using the 2956 // "thread_oop" handle. 2957 2958 // Set the thread field (a JavaThread *) of the 2959 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2960 2961 Handle thread_oop(Thread::current(), 2962 JNIHandles::resolve_non_null(jni_thread)); 2963 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 2964 "must be initialized"); 2965 set_threadObj(thread_oop()); 2966 java_lang_Thread::set_thread(thread_oop(), this); 2967 2968 if (prio == NoPriority) { 2969 prio = java_lang_Thread::priority(thread_oop()); 2970 assert(prio != NoPriority, "A valid priority should be present"); 2971 } 2972 2973 // Push the Java priority down to the native thread; needs Threads_lock 2974 Thread::set_priority(this, prio); 2975 2976 // Add the new thread to the Threads list and set it in motion. 2977 // We must have threads lock in order to call Threads::add. 2978 // It is crucial that we do not block before the thread is 2979 // added to the Threads list for if a GC happens, then the java_thread oop 2980 // will not be visited by GC. 2981 Threads::add(this); 2982 } 2983 2984 oop JavaThread::current_park_blocker() { 2985 // Support for JSR-166 locks 2986 oop thread_oop = threadObj(); 2987 if (thread_oop != NULL && 2988 JDK_Version::current().supports_thread_park_blocker()) { 2989 return java_lang_Thread::park_blocker(thread_oop); 2990 } 2991 return NULL; 2992 } 2993 2994 2995 void JavaThread::print_stack_on(outputStream* st) { 2996 if (!has_last_Java_frame()) return; 2997 ResourceMark rm; 2998 HandleMark hm; 2999 3000 RegisterMap reg_map(this); 3001 vframe* start_vf = last_java_vframe(®_map); 3002 int count = 0; 3003 for (vframe* f = start_vf; f; f = f->sender()) { 3004 if (f->is_java_frame()) { 3005 javaVFrame* jvf = javaVFrame::cast(f); 3006 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3007 3008 // Print out lock information 3009 if (JavaMonitorsInStackTrace) { 3010 jvf->print_lock_info_on(st, count); 3011 } 3012 } else { 3013 // Ignore non-Java frames 3014 } 3015 3016 // Bail-out case for too deep stacks 3017 count++; 3018 if (MaxJavaStackTraceDepth == count) return; 3019 } 3020 } 3021 3022 3023 // JVMTI PopFrame support 3024 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3025 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3026 if (in_bytes(size_in_bytes) != 0) { 3027 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3028 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3029 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3030 } 3031 } 3032 3033 void* JavaThread::popframe_preserved_args() { 3034 return _popframe_preserved_args; 3035 } 3036 3037 ByteSize JavaThread::popframe_preserved_args_size() { 3038 return in_ByteSize(_popframe_preserved_args_size); 3039 } 3040 3041 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3042 int sz = in_bytes(popframe_preserved_args_size()); 3043 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3044 return in_WordSize(sz / wordSize); 3045 } 3046 3047 void JavaThread::popframe_free_preserved_args() { 3048 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3049 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3050 _popframe_preserved_args = NULL; 3051 _popframe_preserved_args_size = 0; 3052 } 3053 3054 #ifndef PRODUCT 3055 3056 void JavaThread::trace_frames() { 3057 tty->print_cr("[Describe stack]"); 3058 int frame_no = 1; 3059 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3060 tty->print(" %d. ", frame_no++); 3061 fst.current()->print_value_on(tty, this); 3062 tty->cr(); 3063 } 3064 } 3065 3066 class PrintAndVerifyOopClosure: public OopClosure { 3067 protected: 3068 template <class T> inline void do_oop_work(T* p) { 3069 oop obj = oopDesc::load_decode_heap_oop(p); 3070 if (obj == NULL) return; 3071 tty->print(INTPTR_FORMAT ": ", p); 3072 if (obj->is_oop_or_null()) { 3073 if (obj->is_objArray()) { 3074 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3075 } else { 3076 obj->print(); 3077 } 3078 } else { 3079 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3080 } 3081 tty->cr(); 3082 } 3083 public: 3084 virtual void do_oop(oop* p) { do_oop_work(p); } 3085 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3086 }; 3087 3088 3089 static void oops_print(frame* f, const RegisterMap *map) { 3090 PrintAndVerifyOopClosure print; 3091 f->print_value(); 3092 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3093 } 3094 3095 // Print our all the locations that contain oops and whether they are 3096 // valid or not. This useful when trying to find the oldest frame 3097 // where an oop has gone bad since the frame walk is from youngest to 3098 // oldest. 3099 void JavaThread::trace_oops() { 3100 tty->print_cr("[Trace oops]"); 3101 frames_do(oops_print); 3102 } 3103 3104 3105 #ifdef ASSERT 3106 // Print or validate the layout of stack frames 3107 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3108 ResourceMark rm; 3109 PRESERVE_EXCEPTION_MARK; 3110 FrameValues values; 3111 int frame_no = 0; 3112 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3113 fst.current()->describe(values, ++frame_no); 3114 if (depth == frame_no) break; 3115 } 3116 if (validate_only) { 3117 values.validate(); 3118 } else { 3119 tty->print_cr("[Describe stack layout]"); 3120 values.print(this); 3121 } 3122 } 3123 #endif 3124 3125 void JavaThread::trace_stack_from(vframe* start_vf) { 3126 ResourceMark rm; 3127 int vframe_no = 1; 3128 for (vframe* f = start_vf; f; f = f->sender()) { 3129 if (f->is_java_frame()) { 3130 javaVFrame::cast(f)->print_activation(vframe_no++); 3131 } else { 3132 f->print(); 3133 } 3134 if (vframe_no > StackPrintLimit) { 3135 tty->print_cr("...<more frames>..."); 3136 return; 3137 } 3138 } 3139 } 3140 3141 3142 void JavaThread::trace_stack() { 3143 if (!has_last_Java_frame()) return; 3144 ResourceMark rm; 3145 HandleMark hm; 3146 RegisterMap reg_map(this); 3147 trace_stack_from(last_java_vframe(®_map)); 3148 } 3149 3150 3151 #endif // PRODUCT 3152 3153 3154 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3155 assert(reg_map != NULL, "a map must be given"); 3156 frame f = last_frame(); 3157 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3158 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3159 } 3160 return NULL; 3161 } 3162 3163 3164 Klass* JavaThread::security_get_caller_class(int depth) { 3165 vframeStream vfst(this); 3166 vfst.security_get_caller_frame(depth); 3167 if (!vfst.at_end()) { 3168 return vfst.method()->method_holder(); 3169 } 3170 return NULL; 3171 } 3172 3173 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3174 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3175 CompileBroker::compiler_thread_loop(); 3176 } 3177 3178 // Create a CompilerThread 3179 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3180 : JavaThread(&compiler_thread_entry) { 3181 _env = NULL; 3182 _log = NULL; 3183 _task = NULL; 3184 _queue = queue; 3185 _counters = counters; 3186 _buffer_blob = NULL; 3187 _scanned_nmethod = NULL; 3188 _compiler = NULL; 3189 3190 #ifndef PRODUCT 3191 _ideal_graph_printer = NULL; 3192 #endif 3193 } 3194 3195 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3196 JavaThread::oops_do(f, cld_f, cf); 3197 if (_scanned_nmethod != NULL && cf != NULL) { 3198 // Safepoints can occur when the sweeper is scanning an nmethod so 3199 // process it here to make sure it isn't unloaded in the middle of 3200 // a scan. 3201 cf->do_code_blob(_scanned_nmethod); 3202 } 3203 } 3204 3205 3206 // ======= Threads ======== 3207 3208 // The Threads class links together all active threads, and provides 3209 // operations over all threads. It is protected by its own Mutex 3210 // lock, which is also used in other contexts to protect thread 3211 // operations from having the thread being operated on from exiting 3212 // and going away unexpectedly (e.g., safepoint synchronization) 3213 3214 JavaThread* Threads::_thread_list = NULL; 3215 int Threads::_number_of_threads = 0; 3216 int Threads::_number_of_non_daemon_threads = 0; 3217 int Threads::_return_code = 0; 3218 size_t JavaThread::_stack_size_at_create = 0; 3219 #ifdef ASSERT 3220 bool Threads::_vm_complete = false; 3221 #endif 3222 3223 // All JavaThreads 3224 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3225 3226 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3227 void Threads::threads_do(ThreadClosure* tc) { 3228 assert_locked_or_safepoint(Threads_lock); 3229 // ALL_JAVA_THREADS iterates through all JavaThreads 3230 ALL_JAVA_THREADS(p) { 3231 tc->do_thread(p); 3232 } 3233 // Someday we could have a table or list of all non-JavaThreads. 3234 // For now, just manually iterate through them. 3235 tc->do_thread(VMThread::vm_thread()); 3236 Universe::heap()->gc_threads_do(tc); 3237 WatcherThread *wt = WatcherThread::watcher_thread(); 3238 // Strictly speaking, the following NULL check isn't sufficient to make sure 3239 // the data for WatcherThread is still valid upon being examined. However, 3240 // considering that WatchThread terminates when the VM is on the way to 3241 // exit at safepoint, the chance of the above is extremely small. The right 3242 // way to prevent termination of WatcherThread would be to acquire 3243 // Terminator_lock, but we can't do that without violating the lock rank 3244 // checking in some cases. 3245 if (wt != NULL) 3246 tc->do_thread(wt); 3247 3248 // If CompilerThreads ever become non-JavaThreads, add them here 3249 } 3250 3251 3252 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3253 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3254 3255 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3256 create_vm_init_libraries(); 3257 } 3258 3259 initialize_class(vmSymbols::java_lang_String(), CHECK); 3260 3261 // Initialize java_lang.System (needed before creating the thread) 3262 initialize_class(vmSymbols::java_lang_System(), CHECK); 3263 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3264 Handle thread_group = create_initial_thread_group(CHECK); 3265 Universe::set_main_thread_group(thread_group()); 3266 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3267 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3268 main_thread->set_threadObj(thread_object); 3269 // Set thread status to running since main thread has 3270 // been started and running. 3271 java_lang_Thread::set_thread_status(thread_object, 3272 java_lang_Thread::RUNNABLE); 3273 3274 // The VM creates & returns objects of this class. Make sure it's initialized. 3275 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3276 3277 // The VM preresolves methods to these classes. Make sure that they get initialized 3278 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3279 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3280 call_initializeSystemClass(CHECK); 3281 3282 // get the Java runtime name after java.lang.System is initialized 3283 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3284 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3285 3286 // an instance of OutOfMemory exception has been allocated earlier 3287 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3288 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3289 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3290 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3291 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3292 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3293 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3294 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3295 } 3296 3297 void Threads::initialize_jsr292_core_classes(TRAPS) { 3298 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3299 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3300 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3301 } 3302 3303 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3304 3305 extern void JDK_Version_init(); 3306 3307 // Check version 3308 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3309 3310 // Initialize the output stream module 3311 ostream_init(); 3312 3313 // Process java launcher properties. 3314 Arguments::process_sun_java_launcher_properties(args); 3315 3316 // Initialize the os module before using TLS 3317 os::init(); 3318 3319 // Initialize system properties. 3320 Arguments::init_system_properties(); 3321 3322 // So that JDK version can be used as a discriminator when parsing arguments 3323 JDK_Version_init(); 3324 3325 // Update/Initialize System properties after JDK version number is known 3326 Arguments::init_version_specific_system_properties(); 3327 3328 // Parse arguments 3329 jint parse_result = Arguments::parse(args); 3330 if (parse_result != JNI_OK) return parse_result; 3331 3332 os::init_before_ergo(); 3333 3334 jint ergo_result = Arguments::apply_ergo(); 3335 if (ergo_result != JNI_OK) return ergo_result; 3336 3337 if (PauseAtStartup) { 3338 os::pause(); 3339 } 3340 3341 HOTSPOT_VM_INIT_BEGIN(); 3342 3343 // Record VM creation timing statistics 3344 TraceVmCreationTime create_vm_timer; 3345 create_vm_timer.start(); 3346 3347 // Timing (must come after argument parsing) 3348 TraceTime timer("Create VM", TraceStartupTime); 3349 3350 // Initialize the os module after parsing the args 3351 jint os_init_2_result = os::init_2(); 3352 if (os_init_2_result != JNI_OK) return os_init_2_result; 3353 3354 jint adjust_after_os_result = Arguments::adjust_after_os(); 3355 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3356 3357 // initialize TLS 3358 ThreadLocalStorage::init(); 3359 3360 // Bootstrap native memory tracking, so it can start recording memory 3361 // activities before worker thread is started. This is the first phase 3362 // of bootstrapping, VM is currently running in single-thread mode. 3363 MemTracker::bootstrap_single_thread(); 3364 3365 // Initialize output stream logging 3366 ostream_init_log(); 3367 3368 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3369 // Must be before create_vm_init_agents() 3370 if (Arguments::init_libraries_at_startup()) { 3371 convert_vm_init_libraries_to_agents(); 3372 } 3373 3374 // Launch -agentlib/-agentpath and converted -Xrun agents 3375 if (Arguments::init_agents_at_startup()) { 3376 create_vm_init_agents(); 3377 } 3378 3379 // Initialize Threads state 3380 _thread_list = NULL; 3381 _number_of_threads = 0; 3382 _number_of_non_daemon_threads = 0; 3383 3384 // Initialize global data structures and create system classes in heap 3385 vm_init_globals(); 3386 3387 // Attach the main thread to this os thread 3388 JavaThread* main_thread = new JavaThread(); 3389 main_thread->set_thread_state(_thread_in_vm); 3390 // must do this before set_active_handles and initialize_thread_local_storage 3391 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3392 // change the stack size recorded here to one based on the java thread 3393 // stacksize. This adjusted size is what is used to figure the placement 3394 // of the guard pages. 3395 main_thread->record_stack_base_and_size(); 3396 main_thread->initialize_thread_local_storage(); 3397 3398 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3399 3400 if (!main_thread->set_as_starting_thread()) { 3401 vm_shutdown_during_initialization( 3402 "Failed necessary internal allocation. Out of swap space"); 3403 delete main_thread; 3404 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3405 return JNI_ENOMEM; 3406 } 3407 3408 // Enable guard page *after* os::create_main_thread(), otherwise it would 3409 // crash Linux VM, see notes in os_linux.cpp. 3410 main_thread->create_stack_guard_pages(); 3411 3412 // Initialize Java-Level synchronization subsystem 3413 ObjectMonitor::Initialize(); 3414 3415 // Second phase of bootstrapping, VM is about entering multi-thread mode 3416 MemTracker::bootstrap_multi_thread(); 3417 3418 // Initialize global modules 3419 jint status = init_globals(); 3420 if (status != JNI_OK) { 3421 delete main_thread; 3422 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3423 return status; 3424 } 3425 3426 // Should be done after the heap is fully created 3427 main_thread->cache_global_variables(); 3428 3429 HandleMark hm; 3430 3431 { MutexLocker mu(Threads_lock); 3432 Threads::add(main_thread); 3433 } 3434 3435 // Any JVMTI raw monitors entered in onload will transition into 3436 // real raw monitor. VM is setup enough here for raw monitor enter. 3437 JvmtiExport::transition_pending_onload_raw_monitors(); 3438 3439 // Fully start NMT 3440 MemTracker::start(); 3441 3442 // Create the VMThread 3443 { TraceTime timer("Start VMThread", TraceStartupTime); 3444 VMThread::create(); 3445 Thread* vmthread = VMThread::vm_thread(); 3446 3447 if (!os::create_thread(vmthread, os::vm_thread)) 3448 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3449 3450 // Wait for the VM thread to become ready, and VMThread::run to initialize 3451 // Monitors can have spurious returns, must always check another state flag 3452 { 3453 MutexLocker ml(Notify_lock); 3454 os::start_thread(vmthread); 3455 while (vmthread->active_handles() == NULL) { 3456 Notify_lock->wait(); 3457 } 3458 } 3459 } 3460 3461 assert(Universe::is_fully_initialized(), "not initialized"); 3462 if (VerifyDuringStartup) { 3463 // Make sure we're starting with a clean slate. 3464 VM_Verify verify_op; 3465 VMThread::execute(&verify_op); 3466 } 3467 3468 Thread* THREAD = Thread::current(); 3469 3470 // At this point, the Universe is initialized, but we have not executed 3471 // any byte code. Now is a good time (the only time) to dump out the 3472 // internal state of the JVM for sharing. 3473 if (DumpSharedSpaces) { 3474 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3475 ShouldNotReachHere(); 3476 } 3477 3478 // Always call even when there are not JVMTI environments yet, since environments 3479 // may be attached late and JVMTI must track phases of VM execution 3480 JvmtiExport::enter_start_phase(); 3481 3482 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3483 JvmtiExport::post_vm_start(); 3484 3485 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3486 3487 // We need this for ClassDataSharing - the initial vm.info property is set 3488 // with the default value of CDS "sharing" which may be reset through 3489 // command line options. 3490 reset_vm_info_property(CHECK_JNI_ERR); 3491 3492 quicken_jni_functions(); 3493 3494 // Must be run after init_ft which initializes ft_enabled 3495 if (TRACE_INITIALIZE() != JNI_OK) { 3496 vm_exit_during_initialization("Failed to initialize tracing backend"); 3497 } 3498 3499 // Set flag that basic initialization has completed. Used by exceptions and various 3500 // debug stuff, that does not work until all basic classes have been initialized. 3501 set_init_completed(); 3502 3503 Metaspace::post_initialize(); 3504 3505 HOTSPOT_VM_INIT_END(); 3506 3507 // record VM initialization completion time 3508 #if INCLUDE_MANAGEMENT 3509 Management::record_vm_init_completed(); 3510 #endif // INCLUDE_MANAGEMENT 3511 3512 // Compute system loader. Note that this has to occur after set_init_completed, since 3513 // valid exceptions may be thrown in the process. 3514 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3515 // set_init_completed has just been called, causing exceptions not to be shortcut 3516 // anymore. We call vm_exit_during_initialization directly instead. 3517 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR); 3518 3519 #if INCLUDE_ALL_GCS 3520 // Support for ConcurrentMarkSweep. This should be cleaned up 3521 // and better encapsulated. The ugly nested if test would go away 3522 // once things are properly refactored. XXX YSR 3523 if (UseConcMarkSweepGC || UseG1GC) { 3524 if (UseConcMarkSweepGC) { 3525 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3526 } else { 3527 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3528 } 3529 } 3530 #endif // INCLUDE_ALL_GCS 3531 3532 // Always call even when there are not JVMTI environments yet, since environments 3533 // may be attached late and JVMTI must track phases of VM execution 3534 JvmtiExport::enter_live_phase(); 3535 3536 // Signal Dispatcher needs to be started before VMInit event is posted 3537 os::signal_init(); 3538 3539 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3540 if (!DisableAttachMechanism) { 3541 AttachListener::vm_start(); 3542 if (StartAttachListener || AttachListener::init_at_startup()) { 3543 AttachListener::init(); 3544 } 3545 } 3546 3547 // Launch -Xrun agents 3548 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3549 // back-end can launch with -Xdebug -Xrunjdwp. 3550 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3551 create_vm_init_libraries(); 3552 } 3553 3554 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3555 JvmtiExport::post_vm_initialized(); 3556 3557 if (TRACE_START() != JNI_OK) { 3558 vm_exit_during_initialization("Failed to start tracing backend."); 3559 } 3560 3561 if (CleanChunkPoolAsync) { 3562 Chunk::start_chunk_pool_cleaner_task(); 3563 } 3564 3565 // initialize compiler(s) 3566 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3567 CompileBroker::compilation_init(); 3568 #endif 3569 3570 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3571 // It is done after compilers are initialized, because otherwise compilations of 3572 // signature polymorphic MH intrinsics can be missed 3573 // (see SystemDictionary::find_method_handle_intrinsic). 3574 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3575 3576 #if INCLUDE_MANAGEMENT 3577 Management::initialize(THREAD); 3578 3579 if (HAS_PENDING_EXCEPTION) { 3580 // management agent fails to start possibly due to 3581 // configuration problem and is responsible for printing 3582 // stack trace if appropriate. Simply exit VM. 3583 vm_exit(1); 3584 } 3585 #endif // INCLUDE_MANAGEMENT 3586 3587 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3588 if (MemProfiling) MemProfiler::engage(); 3589 StatSampler::engage(); 3590 if (CheckJNICalls) JniPeriodicChecker::engage(); 3591 3592 BiasedLocking::init(); 3593 3594 #if INCLUDE_RTM_OPT 3595 RTMLockingCounters::init(); 3596 #endif 3597 3598 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3599 call_postVMInitHook(THREAD); 3600 // The Java side of PostVMInitHook.run must deal with all 3601 // exceptions and provide means of diagnosis. 3602 if (HAS_PENDING_EXCEPTION) { 3603 CLEAR_PENDING_EXCEPTION; 3604 } 3605 } 3606 3607 { 3608 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3609 // Make sure the watcher thread can be started by WatcherThread::start() 3610 // or by dynamic enrollment. 3611 WatcherThread::make_startable(); 3612 // Start up the WatcherThread if there are any periodic tasks 3613 // NOTE: All PeriodicTasks should be registered by now. If they 3614 // aren't, late joiners might appear to start slowly (we might 3615 // take a while to process their first tick). 3616 if (PeriodicTask::num_tasks() > 0) { 3617 WatcherThread::start(); 3618 } 3619 } 3620 3621 // Give os specific code one last chance to start 3622 os::init_3(); 3623 3624 create_vm_timer.end(); 3625 #ifdef ASSERT 3626 _vm_complete = true; 3627 #endif 3628 return JNI_OK; 3629 } 3630 3631 // type for the Agent_OnLoad and JVM_OnLoad entry points 3632 extern "C" { 3633 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3634 } 3635 // Find a command line agent library and return its entry point for 3636 // -agentlib: -agentpath: -Xrun 3637 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3638 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3639 OnLoadEntry_t on_load_entry = NULL; 3640 void *library = NULL; 3641 3642 if (!agent->valid()) { 3643 char buffer[JVM_MAXPATHLEN]; 3644 char ebuf[1024]; 3645 const char *name = agent->name(); 3646 const char *msg = "Could not find agent library "; 3647 3648 // First check to see if agent is statically linked into executable 3649 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3650 library = agent->os_lib(); 3651 } else if (agent->is_absolute_path()) { 3652 library = os::dll_load(name, ebuf, sizeof ebuf); 3653 if (library == NULL) { 3654 const char *sub_msg = " in absolute path, with error: "; 3655 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3656 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3657 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3658 // If we can't find the agent, exit. 3659 vm_exit_during_initialization(buf, NULL); 3660 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3661 } 3662 } else { 3663 // Try to load the agent from the standard dll directory 3664 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3665 name)) { 3666 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3667 } 3668 if (library == NULL) { // Try the local directory 3669 char ns[1] = {0}; 3670 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3671 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3672 } 3673 if (library == NULL) { 3674 const char *sub_msg = " on the library path, with error: "; 3675 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3676 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3677 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3678 // If we can't find the agent, exit. 3679 vm_exit_during_initialization(buf, NULL); 3680 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3681 } 3682 } 3683 } 3684 agent->set_os_lib(library); 3685 agent->set_valid(); 3686 } 3687 3688 // Find the OnLoad function. 3689 on_load_entry = 3690 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3691 false, 3692 on_load_symbols, 3693 num_symbol_entries)); 3694 return on_load_entry; 3695 } 3696 3697 // Find the JVM_OnLoad entry point 3698 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3699 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3700 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3701 } 3702 3703 // Find the Agent_OnLoad entry point 3704 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3705 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3706 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3707 } 3708 3709 // For backwards compatibility with -Xrun 3710 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3711 // treated like -agentpath: 3712 // Must be called before agent libraries are created 3713 void Threads::convert_vm_init_libraries_to_agents() { 3714 AgentLibrary* agent; 3715 AgentLibrary* next; 3716 3717 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3718 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3719 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3720 3721 // If there is an JVM_OnLoad function it will get called later, 3722 // otherwise see if there is an Agent_OnLoad 3723 if (on_load_entry == NULL) { 3724 on_load_entry = lookup_agent_on_load(agent); 3725 if (on_load_entry != NULL) { 3726 // switch it to the agent list -- so that Agent_OnLoad will be called, 3727 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3728 Arguments::convert_library_to_agent(agent); 3729 } else { 3730 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3731 } 3732 } 3733 } 3734 } 3735 3736 // Create agents for -agentlib: -agentpath: and converted -Xrun 3737 // Invokes Agent_OnLoad 3738 // Called very early -- before JavaThreads exist 3739 void Threads::create_vm_init_agents() { 3740 extern struct JavaVM_ main_vm; 3741 AgentLibrary* agent; 3742 3743 JvmtiExport::enter_onload_phase(); 3744 3745 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3746 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3747 3748 if (on_load_entry != NULL) { 3749 // Invoke the Agent_OnLoad function 3750 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3751 if (err != JNI_OK) { 3752 vm_exit_during_initialization("agent library failed to init", agent->name()); 3753 } 3754 } else { 3755 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3756 } 3757 } 3758 JvmtiExport::enter_primordial_phase(); 3759 } 3760 3761 extern "C" { 3762 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3763 } 3764 3765 void Threads::shutdown_vm_agents() { 3766 // Send any Agent_OnUnload notifications 3767 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3768 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3769 extern struct JavaVM_ main_vm; 3770 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3771 3772 // Find the Agent_OnUnload function. 3773 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3774 os::find_agent_function(agent, 3775 false, 3776 on_unload_symbols, 3777 num_symbol_entries)); 3778 3779 // Invoke the Agent_OnUnload function 3780 if (unload_entry != NULL) { 3781 JavaThread* thread = JavaThread::current(); 3782 ThreadToNativeFromVM ttn(thread); 3783 HandleMark hm(thread); 3784 (*unload_entry)(&main_vm); 3785 } 3786 } 3787 } 3788 3789 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3790 // Invokes JVM_OnLoad 3791 void Threads::create_vm_init_libraries() { 3792 extern struct JavaVM_ main_vm; 3793 AgentLibrary* agent; 3794 3795 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3796 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3797 3798 if (on_load_entry != NULL) { 3799 // Invoke the JVM_OnLoad function 3800 JavaThread* thread = JavaThread::current(); 3801 ThreadToNativeFromVM ttn(thread); 3802 HandleMark hm(thread); 3803 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3804 if (err != JNI_OK) { 3805 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3806 } 3807 } else { 3808 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3809 } 3810 } 3811 } 3812 3813 // Last thread running calls java.lang.Shutdown.shutdown() 3814 void JavaThread::invoke_shutdown_hooks() { 3815 HandleMark hm(this); 3816 3817 // We could get here with a pending exception, if so clear it now. 3818 if (this->has_pending_exception()) { 3819 this->clear_pending_exception(); 3820 } 3821 3822 EXCEPTION_MARK; 3823 Klass* k = 3824 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3825 THREAD); 3826 if (k != NULL) { 3827 // SystemDictionary::resolve_or_null will return null if there was 3828 // an exception. If we cannot load the Shutdown class, just don't 3829 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3830 // and finalizers (if runFinalizersOnExit is set) won't be run. 3831 // Note that if a shutdown hook was registered or runFinalizersOnExit 3832 // was called, the Shutdown class would have already been loaded 3833 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3834 instanceKlassHandle shutdown_klass (THREAD, k); 3835 JavaValue result(T_VOID); 3836 JavaCalls::call_static(&result, 3837 shutdown_klass, 3838 vmSymbols::shutdown_method_name(), 3839 vmSymbols::void_method_signature(), 3840 THREAD); 3841 } 3842 CLEAR_PENDING_EXCEPTION; 3843 } 3844 3845 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3846 // the program falls off the end of main(). Another VM exit path is through 3847 // vm_exit() when the program calls System.exit() to return a value or when 3848 // there is a serious error in VM. The two shutdown paths are not exactly 3849 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3850 // and VM_Exit op at VM level. 3851 // 3852 // Shutdown sequence: 3853 // + Shutdown native memory tracking if it is on 3854 // + Wait until we are the last non-daemon thread to execute 3855 // <-- every thing is still working at this moment --> 3856 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3857 // shutdown hooks, run finalizers if finalization-on-exit 3858 // + Call before_exit(), prepare for VM exit 3859 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3860 // currently the only user of this mechanism is File.deleteOnExit()) 3861 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3862 // post thread end and vm death events to JVMTI, 3863 // stop signal thread 3864 // + Call JavaThread::exit(), it will: 3865 // > release JNI handle blocks, remove stack guard pages 3866 // > remove this thread from Threads list 3867 // <-- no more Java code from this thread after this point --> 3868 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3869 // the compiler threads at safepoint 3870 // <-- do not use anything that could get blocked by Safepoint --> 3871 // + Disable tracing at JNI/JVM barriers 3872 // + Set _vm_exited flag for threads that are still running native code 3873 // + Delete this thread 3874 // + Call exit_globals() 3875 // > deletes tty 3876 // > deletes PerfMemory resources 3877 // + Return to caller 3878 3879 bool Threads::destroy_vm() { 3880 JavaThread* thread = JavaThread::current(); 3881 3882 #ifdef ASSERT 3883 _vm_complete = false; 3884 #endif 3885 // Wait until we are the last non-daemon thread to execute 3886 { MutexLocker nu(Threads_lock); 3887 while (Threads::number_of_non_daemon_threads() > 1) 3888 // This wait should make safepoint checks, wait without a timeout, 3889 // and wait as a suspend-equivalent condition. 3890 // 3891 // Note: If the FlatProfiler is running and this thread is waiting 3892 // for another non-daemon thread to finish, then the FlatProfiler 3893 // is waiting for the external suspend request on this thread to 3894 // complete. wait_for_ext_suspend_completion() will eventually 3895 // timeout, but that takes time. Making this wait a suspend- 3896 // equivalent condition solves that timeout problem. 3897 // 3898 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3899 Mutex::_as_suspend_equivalent_flag); 3900 } 3901 3902 // Hang forever on exit if we are reporting an error. 3903 if (ShowMessageBoxOnError && is_error_reported()) { 3904 os::infinite_sleep(); 3905 } 3906 os::wait_for_keypress_at_exit(); 3907 3908 // run Java level shutdown hooks 3909 thread->invoke_shutdown_hooks(); 3910 3911 before_exit(thread); 3912 3913 thread->exit(true); 3914 3915 // Stop VM thread. 3916 { 3917 // 4945125 The vm thread comes to a safepoint during exit. 3918 // GC vm_operations can get caught at the safepoint, and the 3919 // heap is unparseable if they are caught. Grab the Heap_lock 3920 // to prevent this. The GC vm_operations will not be able to 3921 // queue until after the vm thread is dead. After this point, 3922 // we'll never emerge out of the safepoint before the VM exits. 3923 3924 MutexLocker ml(Heap_lock); 3925 3926 VMThread::wait_for_vm_thread_exit(); 3927 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3928 VMThread::destroy(); 3929 } 3930 3931 // clean up ideal graph printers 3932 #if defined(COMPILER2) && !defined(PRODUCT) 3933 IdealGraphPrinter::clean_up(); 3934 #endif 3935 3936 // Now, all Java threads are gone except daemon threads. Daemon threads 3937 // running Java code or in VM are stopped by the Safepoint. However, 3938 // daemon threads executing native code are still running. But they 3939 // will be stopped at native=>Java/VM barriers. Note that we can't 3940 // simply kill or suspend them, as it is inherently deadlock-prone. 3941 3942 #ifndef PRODUCT 3943 // disable function tracing at JNI/JVM barriers 3944 TraceJNICalls = false; 3945 TraceJVMCalls = false; 3946 TraceRuntimeCalls = false; 3947 #endif 3948 3949 VM_Exit::set_vm_exited(); 3950 3951 notify_vm_shutdown(); 3952 3953 delete thread; 3954 3955 // exit_globals() will delete tty 3956 exit_globals(); 3957 3958 return true; 3959 } 3960 3961 3962 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 3963 if (version == JNI_VERSION_1_1) return JNI_TRUE; 3964 return is_supported_jni_version(version); 3965 } 3966 3967 3968 jboolean Threads::is_supported_jni_version(jint version) { 3969 if (version == JNI_VERSION_1_2) return JNI_TRUE; 3970 if (version == JNI_VERSION_1_4) return JNI_TRUE; 3971 if (version == JNI_VERSION_1_6) return JNI_TRUE; 3972 if (version == JNI_VERSION_1_8) return JNI_TRUE; 3973 return JNI_FALSE; 3974 } 3975 3976 3977 void Threads::add(JavaThread* p, bool force_daemon) { 3978 // The threads lock must be owned at this point 3979 assert_locked_or_safepoint(Threads_lock); 3980 3981 // See the comment for this method in thread.hpp for its purpose and 3982 // why it is called here. 3983 p->initialize_queues(); 3984 p->set_next(_thread_list); 3985 _thread_list = p; 3986 _number_of_threads++; 3987 oop threadObj = p->threadObj(); 3988 bool daemon = true; 3989 // Bootstrapping problem: threadObj can be null for initial 3990 // JavaThread (or for threads attached via JNI) 3991 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 3992 _number_of_non_daemon_threads++; 3993 daemon = false; 3994 } 3995 3996 p->set_safepoint_visible(true); 3997 3998 ThreadService::add_thread(p, daemon); 3999 4000 // Possible GC point. 4001 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4002 } 4003 4004 void Threads::remove(JavaThread* p) { 4005 // Extra scope needed for Thread_lock, so we can check 4006 // that we do not remove thread without safepoint code notice 4007 { MutexLocker ml(Threads_lock); 4008 4009 assert(includes(p), "p must be present"); 4010 4011 JavaThread* current = _thread_list; 4012 JavaThread* prev = NULL; 4013 4014 while (current != p) { 4015 prev = current; 4016 current = current->next(); 4017 } 4018 4019 if (prev) { 4020 prev->set_next(current->next()); 4021 } else { 4022 _thread_list = p->next(); 4023 } 4024 _number_of_threads--; 4025 oop threadObj = p->threadObj(); 4026 bool daemon = true; 4027 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4028 _number_of_non_daemon_threads--; 4029 daemon = false; 4030 4031 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4032 // on destroy_vm will wake up. 4033 if (number_of_non_daemon_threads() == 1) 4034 Threads_lock->notify_all(); 4035 } 4036 ThreadService::remove_thread(p, daemon); 4037 4038 // Make sure that safepoint code disregard this thread. This is needed since 4039 // the thread might mess around with locks after this point. This can cause it 4040 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4041 // of this thread since it is removed from the queue. 4042 p->set_terminated_value(); 4043 4044 // Now, this thread is not visible to safepoint 4045 p->set_safepoint_visible(false); 4046 // once the thread becomes safepoint invisible, we can not use its per-thread 4047 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4048 // to release its per-thread recorder here. 4049 MemTracker::thread_exiting(p); 4050 } // unlock Threads_lock 4051 4052 // Since Events::log uses a lock, we grab it outside the Threads_lock 4053 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4054 } 4055 4056 // Threads_lock must be held when this is called (or must be called during a safepoint) 4057 bool Threads::includes(JavaThread* p) { 4058 assert(Threads_lock->is_locked(), "sanity check"); 4059 ALL_JAVA_THREADS(q) { 4060 if (q == p) { 4061 return true; 4062 } 4063 } 4064 return false; 4065 } 4066 4067 // Operations on the Threads list for GC. These are not explicitly locked, 4068 // but the garbage collector must provide a safe context for them to run. 4069 // In particular, these things should never be called when the Threads_lock 4070 // is held by some other thread. (Note: the Safepoint abstraction also 4071 // uses the Threads_lock to guarantee this property. It also makes sure that 4072 // all threads gets blocked when exiting or starting). 4073 4074 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4075 ALL_JAVA_THREADS(p) { 4076 p->oops_do(f, cld_f, cf); 4077 } 4078 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4079 } 4080 4081 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4082 // Introduce a mechanism allowing parallel threads to claim threads as 4083 // root groups. Overhead should be small enough to use all the time, 4084 // even in sequential code. 4085 SharedHeap* sh = SharedHeap::heap(); 4086 // Cannot yet substitute active_workers for n_par_threads 4087 // because of G1CollectedHeap::verify() use of 4088 // SharedHeap::process_roots(). n_par_threads == 0 will 4089 // turn off parallelism in process_roots while active_workers 4090 // is being used for parallelism elsewhere. 4091 bool is_par = sh->n_par_threads() > 0; 4092 assert(!is_par || 4093 (SharedHeap::heap()->n_par_threads() == 4094 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4095 int cp = SharedHeap::heap()->strong_roots_parity(); 4096 ALL_JAVA_THREADS(p) { 4097 if (p->claim_oops_do(is_par, cp)) { 4098 p->oops_do(f, cld_f, cf); 4099 } 4100 } 4101 VMThread* vmt = VMThread::vm_thread(); 4102 if (vmt->claim_oops_do(is_par, cp)) { 4103 vmt->oops_do(f, cld_f, cf); 4104 } 4105 } 4106 4107 #if INCLUDE_ALL_GCS 4108 // Used by ParallelScavenge 4109 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4110 ALL_JAVA_THREADS(p) { 4111 q->enqueue(new ThreadRootsTask(p)); 4112 } 4113 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4114 } 4115 4116 // Used by Parallel Old 4117 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4118 ALL_JAVA_THREADS(p) { 4119 q->enqueue(new ThreadRootsMarkingTask(p)); 4120 } 4121 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4122 } 4123 #endif // INCLUDE_ALL_GCS 4124 4125 void Threads::nmethods_do(CodeBlobClosure* cf) { 4126 ALL_JAVA_THREADS(p) { 4127 p->nmethods_do(cf); 4128 } 4129 VMThread::vm_thread()->nmethods_do(cf); 4130 } 4131 4132 void Threads::metadata_do(void f(Metadata*)) { 4133 ALL_JAVA_THREADS(p) { 4134 p->metadata_do(f); 4135 } 4136 } 4137 4138 void Threads::deoptimized_wrt_marked_nmethods() { 4139 ALL_JAVA_THREADS(p) { 4140 p->deoptimized_wrt_marked_nmethods(); 4141 } 4142 } 4143 4144 4145 // Get count Java threads that are waiting to enter the specified monitor. 4146 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4147 address monitor, bool doLock) { 4148 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4149 "must grab Threads_lock or be at safepoint"); 4150 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4151 4152 int i = 0; 4153 { 4154 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4155 ALL_JAVA_THREADS(p) { 4156 if (p->is_Compiler_thread()) continue; 4157 4158 address pending = (address)p->current_pending_monitor(); 4159 if (pending == monitor) { // found a match 4160 if (i < count) result->append(p); // save the first count matches 4161 i++; 4162 } 4163 } 4164 } 4165 return result; 4166 } 4167 4168 4169 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4170 assert(doLock || 4171 Threads_lock->owned_by_self() || 4172 SafepointSynchronize::is_at_safepoint(), 4173 "must grab Threads_lock or be at safepoint"); 4174 4175 // NULL owner means not locked so we can skip the search 4176 if (owner == NULL) return NULL; 4177 4178 { 4179 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4180 ALL_JAVA_THREADS(p) { 4181 // first, see if owner is the address of a Java thread 4182 if (owner == (address)p) return p; 4183 } 4184 } 4185 // Cannot assert on lack of success here since this function may be 4186 // used by code that is trying to report useful problem information 4187 // like deadlock detection. 4188 if (UseHeavyMonitors) return NULL; 4189 4190 // 4191 // If we didn't find a matching Java thread and we didn't force use of 4192 // heavyweight monitors, then the owner is the stack address of the 4193 // Lock Word in the owning Java thread's stack. 4194 // 4195 JavaThread* the_owner = NULL; 4196 { 4197 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4198 ALL_JAVA_THREADS(q) { 4199 if (q->is_lock_owned(owner)) { 4200 the_owner = q; 4201 break; 4202 } 4203 } 4204 } 4205 // cannot assert on lack of success here; see above comment 4206 return the_owner; 4207 } 4208 4209 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4210 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4211 char buf[32]; 4212 st->print_cr("%s", os::local_time_string(buf, sizeof(buf))); 4213 4214 st->print_cr("Full thread dump %s (%s %s):", 4215 Abstract_VM_Version::vm_name(), 4216 Abstract_VM_Version::vm_release(), 4217 Abstract_VM_Version::vm_info_string() 4218 ); 4219 st->cr(); 4220 4221 #if INCLUDE_ALL_GCS 4222 // Dump concurrent locks 4223 ConcurrentLocksDump concurrent_locks; 4224 if (print_concurrent_locks) { 4225 concurrent_locks.dump_at_safepoint(); 4226 } 4227 #endif // INCLUDE_ALL_GCS 4228 4229 ALL_JAVA_THREADS(p) { 4230 ResourceMark rm; 4231 p->print_on(st); 4232 if (print_stacks) { 4233 if (internal_format) { 4234 p->trace_stack(); 4235 } else { 4236 p->print_stack_on(st); 4237 } 4238 } 4239 st->cr(); 4240 #if INCLUDE_ALL_GCS 4241 if (print_concurrent_locks) { 4242 concurrent_locks.print_locks_on(p, st); 4243 } 4244 #endif // INCLUDE_ALL_GCS 4245 } 4246 4247 VMThread::vm_thread()->print_on(st); 4248 st->cr(); 4249 Universe::heap()->print_gc_threads_on(st); 4250 WatcherThread* wt = WatcherThread::watcher_thread(); 4251 if (wt != NULL) { 4252 wt->print_on(st); 4253 st->cr(); 4254 } 4255 CompileBroker::print_compiler_threads_on(st); 4256 st->flush(); 4257 } 4258 4259 // Threads::print_on_error() is called by fatal error handler. It's possible 4260 // that VM is not at safepoint and/or current thread is inside signal handler. 4261 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4262 // memory (even in resource area), it might deadlock the error handler. 4263 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4264 bool found_current = false; 4265 st->print_cr("Java Threads: ( => current thread )"); 4266 ALL_JAVA_THREADS(thread) { 4267 bool is_current = (current == thread); 4268 found_current = found_current || is_current; 4269 4270 st->print("%s", is_current ? "=>" : " "); 4271 4272 st->print(PTR_FORMAT, thread); 4273 st->print(" "); 4274 thread->print_on_error(st, buf, buflen); 4275 st->cr(); 4276 } 4277 st->cr(); 4278 4279 st->print_cr("Other Threads:"); 4280 if (VMThread::vm_thread()) { 4281 bool is_current = (current == VMThread::vm_thread()); 4282 found_current = found_current || is_current; 4283 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4284 4285 st->print(PTR_FORMAT, VMThread::vm_thread()); 4286 st->print(" "); 4287 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4288 st->cr(); 4289 } 4290 WatcherThread* wt = WatcherThread::watcher_thread(); 4291 if (wt != NULL) { 4292 bool is_current = (current == wt); 4293 found_current = found_current || is_current; 4294 st->print("%s", is_current ? "=>" : " "); 4295 4296 st->print(PTR_FORMAT, wt); 4297 st->print(" "); 4298 wt->print_on_error(st, buf, buflen); 4299 st->cr(); 4300 } 4301 if (!found_current) { 4302 st->cr(); 4303 st->print("=>" PTR_FORMAT " (exited) ", current); 4304 current->print_on_error(st, buf, buflen); 4305 st->cr(); 4306 } 4307 } 4308 4309 // Internal SpinLock and Mutex 4310 // Based on ParkEvent 4311 4312 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4313 // 4314 // We employ SpinLocks _only for low-contention, fixed-length 4315 // short-duration critical sections where we're concerned 4316 // about native mutex_t or HotSpot Mutex:: latency. 4317 // The mux construct provides a spin-then-block mutual exclusion 4318 // mechanism. 4319 // 4320 // Testing has shown that contention on the ListLock guarding gFreeList 4321 // is common. If we implement ListLock as a simple SpinLock it's common 4322 // for the JVM to devolve to yielding with little progress. This is true 4323 // despite the fact that the critical sections protected by ListLock are 4324 // extremely short. 4325 // 4326 // TODO-FIXME: ListLock should be of type SpinLock. 4327 // We should make this a 1st-class type, integrated into the lock 4328 // hierarchy as leaf-locks. Critically, the SpinLock structure 4329 // should have sufficient padding to avoid false-sharing and excessive 4330 // cache-coherency traffic. 4331 4332 4333 typedef volatile int SpinLockT; 4334 4335 void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4336 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4337 return; // normal fast-path return 4338 } 4339 4340 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4341 TEVENT(SpinAcquire - ctx); 4342 int ctr = 0; 4343 int Yields = 0; 4344 for (;;) { 4345 while (*adr != 0) { 4346 ++ctr; 4347 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4348 if (Yields > 5) { 4349 os::naked_short_sleep(1); 4350 } else { 4351 os::naked_yield(); 4352 ++Yields; 4353 } 4354 } else { 4355 SpinPause(); 4356 } 4357 } 4358 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4359 } 4360 } 4361 4362 void Thread::SpinRelease (volatile int * adr) { 4363 assert(*adr != 0, "invariant"); 4364 OrderAccess::fence(); // guarantee at least release consistency. 4365 // Roach-motel semantics. 4366 // It's safe if subsequent LDs and STs float "up" into the critical section, 4367 // but prior LDs and STs within the critical section can't be allowed 4368 // to reorder or float past the ST that releases the lock. 4369 // Loads and stores in the critical section - which appear in program 4370 // order before the store that releases the lock - must also appear 4371 // before the store that releases the lock in memory visibility order. 4372 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4373 // the ST of 0 into the lock-word which releases the lock, so fence 4374 // more than covers this on all platforms. 4375 *adr = 0; 4376 } 4377 4378 // muxAcquire and muxRelease: 4379 // 4380 // * muxAcquire and muxRelease support a single-word lock-word construct. 4381 // The LSB of the word is set IFF the lock is held. 4382 // The remainder of the word points to the head of a singly-linked list 4383 // of threads blocked on the lock. 4384 // 4385 // * The current implementation of muxAcquire-muxRelease uses its own 4386 // dedicated Thread._MuxEvent instance. If we're interested in 4387 // minimizing the peak number of extant ParkEvent instances then 4388 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4389 // as certain invariants were satisfied. Specifically, care would need 4390 // to be taken with regards to consuming unpark() "permits". 4391 // A safe rule of thumb is that a thread would never call muxAcquire() 4392 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4393 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4394 // consume an unpark() permit intended for monitorenter, for instance. 4395 // One way around this would be to widen the restricted-range semaphore 4396 // implemented in park(). Another alternative would be to provide 4397 // multiple instances of the PlatformEvent() for each thread. One 4398 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4399 // 4400 // * Usage: 4401 // -- Only as leaf locks 4402 // -- for short-term locking only as muxAcquire does not perform 4403 // thread state transitions. 4404 // 4405 // Alternatives: 4406 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4407 // but with parking or spin-then-park instead of pure spinning. 4408 // * Use Taura-Oyama-Yonenzawa locks. 4409 // * It's possible to construct a 1-0 lock if we encode the lockword as 4410 // (List,LockByte). Acquire will CAS the full lockword while Release 4411 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4412 // acquiring threads use timers (ParkTimed) to detect and recover from 4413 // the stranding window. Thread/Node structures must be aligned on 256-byte 4414 // boundaries by using placement-new. 4415 // * Augment MCS with advisory back-link fields maintained with CAS(). 4416 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4417 // The validity of the backlinks must be ratified before we trust the value. 4418 // If the backlinks are invalid the exiting thread must back-track through the 4419 // the forward links, which are always trustworthy. 4420 // * Add a successor indication. The LockWord is currently encoded as 4421 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4422 // to provide the usual futile-wakeup optimization. 4423 // See RTStt for details. 4424 // * Consider schedctl.sc_nopreempt to cover the critical section. 4425 // 4426 4427 4428 typedef volatile intptr_t MutexT; // Mux Lock-word 4429 enum MuxBits { LOCKBIT = 1 }; 4430 4431 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4432 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4433 if (w == 0) return; 4434 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4435 return; 4436 } 4437 4438 TEVENT(muxAcquire - Contention); 4439 ParkEvent * const Self = Thread::current()->_MuxEvent; 4440 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4441 for (;;) { 4442 int its = (os::is_MP() ? 100 : 0) + 1; 4443 4444 // Optional spin phase: spin-then-park strategy 4445 while (--its >= 0) { 4446 w = *Lock; 4447 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4448 return; 4449 } 4450 } 4451 4452 Self->reset(); 4453 Self->OnList = intptr_t(Lock); 4454 // The following fence() isn't _strictly necessary as the subsequent 4455 // CAS() both serializes execution and ratifies the fetched *Lock value. 4456 OrderAccess::fence(); 4457 for (;;) { 4458 w = *Lock; 4459 if ((w & LOCKBIT) == 0) { 4460 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4461 Self->OnList = 0; // hygiene - allows stronger asserts 4462 return; 4463 } 4464 continue; // Interference -- *Lock changed -- Just retry 4465 } 4466 assert(w & LOCKBIT, "invariant"); 4467 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4468 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4469 } 4470 4471 while (Self->OnList != 0) { 4472 Self->park(); 4473 } 4474 } 4475 } 4476 4477 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4478 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4479 if (w == 0) return; 4480 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4481 return; 4482 } 4483 4484 TEVENT(muxAcquire - Contention); 4485 ParkEvent * ReleaseAfter = NULL; 4486 if (ev == NULL) { 4487 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4488 } 4489 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4490 for (;;) { 4491 guarantee(ev->OnList == 0, "invariant"); 4492 int its = (os::is_MP() ? 100 : 0) + 1; 4493 4494 // Optional spin phase: spin-then-park strategy 4495 while (--its >= 0) { 4496 w = *Lock; 4497 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4498 if (ReleaseAfter != NULL) { 4499 ParkEvent::Release(ReleaseAfter); 4500 } 4501 return; 4502 } 4503 } 4504 4505 ev->reset(); 4506 ev->OnList = intptr_t(Lock); 4507 // The following fence() isn't _strictly necessary as the subsequent 4508 // CAS() both serializes execution and ratifies the fetched *Lock value. 4509 OrderAccess::fence(); 4510 for (;;) { 4511 w = *Lock; 4512 if ((w & LOCKBIT) == 0) { 4513 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4514 ev->OnList = 0; 4515 // We call ::Release while holding the outer lock, thus 4516 // artificially lengthening the critical section. 4517 // Consider deferring the ::Release() until the subsequent unlock(), 4518 // after we've dropped the outer lock. 4519 if (ReleaseAfter != NULL) { 4520 ParkEvent::Release(ReleaseAfter); 4521 } 4522 return; 4523 } 4524 continue; // Interference -- *Lock changed -- Just retry 4525 } 4526 assert(w & LOCKBIT, "invariant"); 4527 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4528 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4529 } 4530 4531 while (ev->OnList != 0) { 4532 ev->park(); 4533 } 4534 } 4535 } 4536 4537 // Release() must extract a successor from the list and then wake that thread. 4538 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4539 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4540 // Release() would : 4541 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4542 // (B) Extract a successor from the private list "in-hand" 4543 // (C) attempt to CAS() the residual back into *Lock over null. 4544 // If there were any newly arrived threads and the CAS() would fail. 4545 // In that case Release() would detach the RATs, re-merge the list in-hand 4546 // with the RATs and repeat as needed. Alternately, Release() might 4547 // detach and extract a successor, but then pass the residual list to the wakee. 4548 // The wakee would be responsible for reattaching and remerging before it 4549 // competed for the lock. 4550 // 4551 // Both "pop" and DMR are immune from ABA corruption -- there can be 4552 // multiple concurrent pushers, but only one popper or detacher. 4553 // This implementation pops from the head of the list. This is unfair, 4554 // but tends to provide excellent throughput as hot threads remain hot. 4555 // (We wake recently run threads first). 4556 // 4557 // All paths through muxRelease() will execute a CAS. 4558 // Release consistency -- We depend on the CAS in muxRelease() to provide full 4559 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4560 // executed within the critical section are complete and globally visible before the 4561 // store (CAS) to the lock-word that releases the lock becomes globally visible. 4562 void Thread::muxRelease (volatile intptr_t * Lock) { 4563 for (;;) { 4564 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4565 assert(w & LOCKBIT, "invariant"); 4566 if (w == LOCKBIT) return; 4567 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4568 assert(List != NULL, "invariant"); 4569 assert(List->OnList == intptr_t(Lock), "invariant"); 4570 ParkEvent * const nxt = List->ListNext; 4571 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4572 4573 // The following CAS() releases the lock and pops the head element. 4574 // The CAS() also ratifies the previously fetched lock-word value. 4575 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4576 continue; 4577 } 4578 List->OnList = 0; 4579 OrderAccess::fence(); 4580 List->unpark(); 4581 return; 4582 } 4583 } 4584 4585 4586 void Threads::verify() { 4587 ALL_JAVA_THREADS(p) { 4588 p->verify(); 4589 } 4590 VMThread* thread = VMThread::vm_thread(); 4591 if (thread != NULL) thread->verify(); 4592 }