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 #ifdef TARGET_OS_FAMILY_linux 89 # include "os_linux.inline.hpp" 90 #endif 91 #ifdef TARGET_OS_FAMILY_solaris 92 # include "os_solaris.inline.hpp" 93 #endif 94 #ifdef TARGET_OS_FAMILY_windows 95 # include "os_windows.inline.hpp" 96 #endif 97 #ifdef TARGET_OS_FAMILY_bsd 98 # include "os_bsd.inline.hpp" 99 #endif 100 #if INCLUDE_ALL_GCS 101 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 102 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 103 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 104 #endif // INCLUDE_ALL_GCS 105 #ifdef COMPILER1 106 #include "c1/c1_Compiler.hpp" 107 #endif 108 #ifdef COMPILER2 109 #include "opto/c2compiler.hpp" 110 #include "opto/idealGraphPrinter.hpp" 111 #endif 112 #if INCLUDE_RTM_OPT 113 #include "runtime/rtmLocking.hpp" 114 #endif 115 116 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 117 118 #ifdef DTRACE_ENABLED 119 120 // Only bother with this argument setup if dtrace is available 121 122 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 123 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 124 125 #define DTRACE_THREAD_PROBE(probe, javathread) \ 126 { \ 127 ResourceMark rm(this); \ 128 int len = 0; \ 129 const char* name = (javathread)->get_thread_name(); \ 130 len = strlen(name); \ 131 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 132 (char *) name, len, \ 133 java_lang_Thread::thread_id((javathread)->threadObj()), \ 134 (uintptr_t) (javathread)->osthread()->thread_id(), \ 135 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 136 } 137 138 #else // ndef DTRACE_ENABLED 139 140 #define DTRACE_THREAD_PROBE(probe, javathread) 141 142 #endif // ndef DTRACE_ENABLED 143 144 145 // Class hierarchy 146 // - Thread 147 // - VMThread 148 // - WatcherThread 149 // - ConcurrentMarkSweepThread 150 // - JavaThread 151 // - CompilerThread 152 153 // ======= Thread ======== 154 // Support for forcing alignment of thread objects for biased locking 155 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 156 if (UseBiasedLocking) { 157 const int alignment = markOopDesc::biased_lock_alignment; 158 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 159 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 160 : AllocateHeap(aligned_size, flags, CURRENT_PC, 161 AllocFailStrategy::RETURN_NULL); 162 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 163 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 164 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 165 "JavaThread alignment code overflowed allocated storage"); 166 if (TraceBiasedLocking) { 167 if (aligned_addr != real_malloc_addr) 168 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 169 real_malloc_addr, aligned_addr); 170 } 171 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 172 return aligned_addr; 173 } else { 174 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 175 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 176 } 177 } 178 179 void Thread::operator delete(void* p) { 180 if (UseBiasedLocking) { 181 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 182 FreeHeap(real_malloc_addr, mtThread); 183 } else { 184 FreeHeap(p, mtThread); 185 } 186 } 187 188 189 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 190 // JavaThread 191 192 193 Thread::Thread() { 194 // stack and get_thread 195 set_stack_base(NULL); 196 set_stack_size(0); 197 set_self_raw_id(0); 198 set_lgrp_id(-1); 199 200 // allocated data structures 201 set_osthread(NULL); 202 set_resource_area(new (mtThread)ResourceArea()); 203 DEBUG_ONLY(_current_resource_mark = NULL;) 204 set_handle_area(new (mtThread) HandleArea(NULL)); 205 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 206 set_active_handles(NULL); 207 set_free_handle_block(NULL); 208 set_last_handle_mark(NULL); 209 210 // This initial value ==> never claimed. 211 _oops_do_parity = 0; 212 213 // the handle mark links itself to last_handle_mark 214 new HandleMark(this); 215 216 // plain initialization 217 debug_only(_owned_locks = NULL;) 218 debug_only(_allow_allocation_count = 0;) 219 NOT_PRODUCT(_allow_safepoint_count = 0;) 220 NOT_PRODUCT(_skip_gcalot = false;) 221 _jvmti_env_iteration_count = 0; 222 set_allocated_bytes(0); 223 _vm_operation_started_count = 0; 224 _vm_operation_completed_count = 0; 225 _current_pending_monitor = NULL; 226 _current_pending_monitor_is_from_java = true; 227 _current_waiting_monitor = NULL; 228 _num_nested_signal = 0; 229 omFreeList = NULL; 230 omFreeCount = 0; 231 omFreeProvision = 32; 232 omInUseList = NULL; 233 omInUseCount = 0; 234 235 #ifdef ASSERT 236 _visited_for_critical_count = false; 237 #endif 238 239 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 240 _suspend_flags = 0; 241 242 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 243 _hashStateX = os::random(); 244 _hashStateY = 842502087; 245 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 246 _hashStateW = 273326509; 247 248 _OnTrap = 0; 249 _schedctl = NULL; 250 _Stalled = 0; 251 _TypeTag = 0x2BAD; 252 253 // Many of the following fields are effectively final - immutable 254 // Note that nascent threads can't use the Native Monitor-Mutex 255 // construct until the _MutexEvent is initialized ... 256 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 257 // we might instead use a stack of ParkEvents that we could provision on-demand. 258 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 259 // and ::Release() 260 _ParkEvent = ParkEvent::Allocate(this); 261 _SleepEvent = ParkEvent::Allocate(this); 262 _MutexEvent = ParkEvent::Allocate(this); 263 _MuxEvent = ParkEvent::Allocate(this); 264 265 #ifdef CHECK_UNHANDLED_OOPS 266 if (CheckUnhandledOops) { 267 _unhandled_oops = new UnhandledOops(this); 268 } 269 #endif // CHECK_UNHANDLED_OOPS 270 #ifdef ASSERT 271 if (UseBiasedLocking) { 272 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 273 assert(this == _real_malloc_address || 274 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 275 "bug in forced alignment of thread objects"); 276 } 277 #endif /* ASSERT */ 278 } 279 280 void Thread::initialize_thread_local_storage() { 281 // Note: Make sure this method only calls 282 // non-blocking operations. Otherwise, it might not work 283 // with the thread-startup/safepoint interaction. 284 285 // During Java thread startup, safepoint code should allow this 286 // method to complete because it may need to allocate memory to 287 // store information for the new thread. 288 289 // initialize structure dependent on thread local storage 290 ThreadLocalStorage::set_thread(this); 291 } 292 293 void Thread::record_stack_base_and_size() { 294 set_stack_base(os::current_stack_base()); 295 set_stack_size(os::current_stack_size()); 296 if (is_Java_thread()) { 297 ((JavaThread*) this)->set_stack_overflow_limit(); 298 } 299 // CR 7190089: on Solaris, primordial thread's stack is adjusted 300 // in initialize_thread(). Without the adjustment, stack size is 301 // incorrect if stack is set to unlimited (ulimit -s unlimited). 302 // So far, only Solaris has real implementation of initialize_thread(). 303 // 304 // set up any platform-specific state. 305 os::initialize_thread(this); 306 307 #if INCLUDE_NMT 308 // record thread's native stack, stack grows downward 309 address stack_low_addr = stack_base() - stack_size(); 310 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 311 CURRENT_PC); 312 #endif // INCLUDE_NMT 313 } 314 315 316 Thread::~Thread() { 317 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 318 ObjectSynchronizer::omFlush(this); 319 320 EVENT_THREAD_DESTRUCT(this); 321 322 // stack_base can be NULL if the thread is never started or exited before 323 // record_stack_base_and_size called. Although, we would like to ensure 324 // that all started threads do call record_stack_base_and_size(), there is 325 // not proper way to enforce that. 326 #if INCLUDE_NMT 327 if (_stack_base != NULL) { 328 address low_stack_addr = stack_base() - stack_size(); 329 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); 330 #ifdef ASSERT 331 set_stack_base(NULL); 332 #endif 333 } 334 #endif // INCLUDE_NMT 335 336 // deallocate data structures 337 delete resource_area(); 338 // since the handle marks are using the handle area, we have to deallocated the root 339 // handle mark before deallocating the thread's handle area, 340 assert(last_handle_mark() != NULL, "check we have an element"); 341 delete last_handle_mark(); 342 assert(last_handle_mark() == NULL, "check we have reached the end"); 343 344 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 345 // We NULL out the fields for good hygiene. 346 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 347 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 348 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 349 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 350 351 delete handle_area(); 352 delete metadata_handles(); 353 354 // osthread() can be NULL, if creation of thread failed. 355 if (osthread() != NULL) os::free_thread(osthread()); 356 357 delete _SR_lock; 358 359 // clear thread local storage if the Thread is deleting itself 360 if (this == Thread::current()) { 361 ThreadLocalStorage::set_thread(NULL); 362 } else { 363 // In the case where we're not the current thread, invalidate all the 364 // caches in case some code tries to get the current thread or the 365 // thread that was destroyed, and gets stale information. 366 ThreadLocalStorage::invalidate_all(); 367 } 368 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 369 } 370 371 // NOTE: dummy function for assertion purpose. 372 void Thread::run() { 373 ShouldNotReachHere(); 374 } 375 376 #ifdef ASSERT 377 // Private method to check for dangling thread pointer 378 void check_for_dangling_thread_pointer(Thread *thread) { 379 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 380 "possibility of dangling Thread pointer"); 381 } 382 #endif 383 384 385 #ifndef PRODUCT 386 // Tracing method for basic thread operations 387 void Thread::trace(const char* msg, const Thread* const thread) { 388 if (!TraceThreadEvents) return; 389 ResourceMark rm; 390 ThreadCritical tc; 391 const char *name = "non-Java thread"; 392 int prio = -1; 393 if (thread->is_Java_thread() 394 && !thread->is_Compiler_thread()) { 395 // The Threads_lock must be held to get information about 396 // this thread but may not be in some situations when 397 // tracing thread events. 398 bool release_Threads_lock = false; 399 if (!Threads_lock->owned_by_self()) { 400 Threads_lock->lock(); 401 release_Threads_lock = true; 402 } 403 JavaThread* jt = (JavaThread *)thread; 404 name = (char *)jt->get_thread_name(); 405 oop thread_oop = jt->threadObj(); 406 if (thread_oop != NULL) { 407 prio = java_lang_Thread::priority(thread_oop); 408 } 409 if (release_Threads_lock) { 410 Threads_lock->unlock(); 411 } 412 } 413 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 414 } 415 #endif 416 417 418 ThreadPriority Thread::get_priority(const Thread* const thread) { 419 trace("get priority", thread); 420 ThreadPriority priority; 421 // Can return an error! 422 (void)os::get_priority(thread, priority); 423 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 424 return priority; 425 } 426 427 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 428 trace("set priority", thread); 429 debug_only(check_for_dangling_thread_pointer(thread);) 430 // Can return an error! 431 (void)os::set_priority(thread, priority); 432 } 433 434 435 void Thread::start(Thread* thread) { 436 trace("start", thread); 437 // Start is different from resume in that its safety is guaranteed by context or 438 // being called from a Java method synchronized on the Thread object. 439 if (!DisableStartThread) { 440 if (thread->is_Java_thread()) { 441 // Initialize the thread state to RUNNABLE before starting this thread. 442 // Can not set it after the thread started because we do not know the 443 // exact thread state at that time. It could be in MONITOR_WAIT or 444 // in SLEEPING or some other state. 445 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 446 java_lang_Thread::RUNNABLE); 447 } 448 os::start_thread(thread); 449 } 450 } 451 452 // Enqueue a VM_Operation to do the job for us - sometime later 453 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 454 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 455 VMThread::execute(vm_stop); 456 } 457 458 459 // 460 // Check if an external suspend request has completed (or has been 461 // cancelled). Returns true if the thread is externally suspended and 462 // false otherwise. 463 // 464 // The bits parameter returns information about the code path through 465 // the routine. Useful for debugging: 466 // 467 // set in is_ext_suspend_completed(): 468 // 0x00000001 - routine was entered 469 // 0x00000010 - routine return false at end 470 // 0x00000100 - thread exited (return false) 471 // 0x00000200 - suspend request cancelled (return false) 472 // 0x00000400 - thread suspended (return true) 473 // 0x00001000 - thread is in a suspend equivalent state (return true) 474 // 0x00002000 - thread is native and walkable (return true) 475 // 0x00004000 - thread is native_trans and walkable (needed retry) 476 // 477 // set in wait_for_ext_suspend_completion(): 478 // 0x00010000 - routine was entered 479 // 0x00020000 - suspend request cancelled before loop (return false) 480 // 0x00040000 - thread suspended before loop (return true) 481 // 0x00080000 - suspend request cancelled in loop (return false) 482 // 0x00100000 - thread suspended in loop (return true) 483 // 0x00200000 - suspend not completed during retry loop (return false) 484 // 485 486 // Helper class for tracing suspend wait debug bits. 487 // 488 // 0x00000100 indicates that the target thread exited before it could 489 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 490 // 0x00080000 each indicate a cancelled suspend request so they don't 491 // count as wait failures either. 492 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 493 494 class TraceSuspendDebugBits : public StackObj { 495 private: 496 JavaThread * jt; 497 bool is_wait; 498 bool called_by_wait; // meaningful when !is_wait 499 uint32_t * bits; 500 501 public: 502 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 503 uint32_t *_bits) { 504 jt = _jt; 505 is_wait = _is_wait; 506 called_by_wait = _called_by_wait; 507 bits = _bits; 508 } 509 510 ~TraceSuspendDebugBits() { 511 if (!is_wait) { 512 #if 1 513 // By default, don't trace bits for is_ext_suspend_completed() calls. 514 // That trace is very chatty. 515 return; 516 #else 517 if (!called_by_wait) { 518 // If tracing for is_ext_suspend_completed() is enabled, then only 519 // trace calls to it from wait_for_ext_suspend_completion() 520 return; 521 } 522 #endif 523 } 524 525 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 526 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 527 MutexLocker ml(Threads_lock); // needed for get_thread_name() 528 ResourceMark rm; 529 530 tty->print_cr( 531 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 532 jt->get_thread_name(), *bits); 533 534 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 535 } 536 } 537 } 538 }; 539 #undef DEBUG_FALSE_BITS 540 541 542 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 543 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 544 545 bool did_trans_retry = false; // only do thread_in_native_trans retry once 546 bool do_trans_retry; // flag to force the retry 547 548 *bits |= 0x00000001; 549 550 do { 551 do_trans_retry = false; 552 553 if (is_exiting()) { 554 // Thread is in the process of exiting. This is always checked 555 // first to reduce the risk of dereferencing a freed JavaThread. 556 *bits |= 0x00000100; 557 return false; 558 } 559 560 if (!is_external_suspend()) { 561 // Suspend request is cancelled. This is always checked before 562 // is_ext_suspended() to reduce the risk of a rogue resume 563 // confusing the thread that made the suspend request. 564 *bits |= 0x00000200; 565 return false; 566 } 567 568 if (is_ext_suspended()) { 569 // thread is suspended 570 *bits |= 0x00000400; 571 return true; 572 } 573 574 // Now that we no longer do hard suspends of threads running 575 // native code, the target thread can be changing thread state 576 // while we are in this routine: 577 // 578 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 579 // 580 // We save a copy of the thread state as observed at this moment 581 // and make our decision about suspend completeness based on the 582 // copy. This closes the race where the thread state is seen as 583 // _thread_in_native_trans in the if-thread_blocked check, but is 584 // seen as _thread_blocked in if-thread_in_native_trans check. 585 JavaThreadState save_state = thread_state(); 586 587 if (save_state == _thread_blocked && is_suspend_equivalent()) { 588 // If the thread's state is _thread_blocked and this blocking 589 // condition is known to be equivalent to a suspend, then we can 590 // consider the thread to be externally suspended. This means that 591 // the code that sets _thread_blocked has been modified to do 592 // self-suspension if the blocking condition releases. We also 593 // used to check for CONDVAR_WAIT here, but that is now covered by 594 // the _thread_blocked with self-suspension check. 595 // 596 // Return true since we wouldn't be here unless there was still an 597 // external suspend request. 598 *bits |= 0x00001000; 599 return true; 600 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 601 // Threads running native code will self-suspend on native==>VM/Java 602 // transitions. If its stack is walkable (should always be the case 603 // unless this function is called before the actual java_suspend() 604 // call), then the wait is done. 605 *bits |= 0x00002000; 606 return true; 607 } else if (!called_by_wait && !did_trans_retry && 608 save_state == _thread_in_native_trans && 609 frame_anchor()->walkable()) { 610 // The thread is transitioning from thread_in_native to another 611 // thread state. check_safepoint_and_suspend_for_native_trans() 612 // will force the thread to self-suspend. If it hasn't gotten 613 // there yet we may have caught the thread in-between the native 614 // code check above and the self-suspend. Lucky us. If we were 615 // called by wait_for_ext_suspend_completion(), then it 616 // will be doing the retries so we don't have to. 617 // 618 // Since we use the saved thread state in the if-statement above, 619 // there is a chance that the thread has already transitioned to 620 // _thread_blocked by the time we get here. In that case, we will 621 // make a single unnecessary pass through the logic below. This 622 // doesn't hurt anything since we still do the trans retry. 623 624 *bits |= 0x00004000; 625 626 // Once the thread leaves thread_in_native_trans for another 627 // thread state, we break out of this retry loop. We shouldn't 628 // need this flag to prevent us from getting back here, but 629 // sometimes paranoia is good. 630 did_trans_retry = true; 631 632 // We wait for the thread to transition to a more usable state. 633 for (int i = 1; i <= SuspendRetryCount; i++) { 634 // We used to do an "os::yield_all(i)" call here with the intention 635 // that yielding would increase on each retry. However, the parameter 636 // is ignored on Linux which means the yield didn't scale up. Waiting 637 // on the SR_lock below provides a much more predictable scale up for 638 // the delay. It also provides a simple/direct point to check for any 639 // safepoint requests from the VMThread 640 641 // temporarily drops SR_lock while doing wait with safepoint check 642 // (if we're a JavaThread - the WatcherThread can also call this) 643 // and increase delay with each retry 644 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 645 646 // check the actual thread state instead of what we saved above 647 if (thread_state() != _thread_in_native_trans) { 648 // the thread has transitioned to another thread state so 649 // try all the checks (except this one) one more time. 650 do_trans_retry = true; 651 break; 652 } 653 } // end retry loop 654 655 656 } 657 } while (do_trans_retry); 658 659 *bits |= 0x00000010; 660 return false; 661 } 662 663 // 664 // Wait for an external suspend request to complete (or be cancelled). 665 // Returns true if the thread is externally suspended and false otherwise. 666 // 667 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 668 uint32_t *bits) { 669 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 670 false /* !called_by_wait */, bits); 671 672 // local flag copies to minimize SR_lock hold time 673 bool is_suspended; 674 bool pending; 675 uint32_t reset_bits; 676 677 // set a marker so is_ext_suspend_completed() knows we are the caller 678 *bits |= 0x00010000; 679 680 // We use reset_bits to reinitialize the bits value at the top of 681 // each retry loop. This allows the caller to make use of any 682 // unused bits for their own marking purposes. 683 reset_bits = *bits; 684 685 { 686 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 687 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 688 delay, bits); 689 pending = is_external_suspend(); 690 } 691 // must release SR_lock to allow suspension to complete 692 693 if (!pending) { 694 // A cancelled suspend request is the only false return from 695 // is_ext_suspend_completed() that keeps us from entering the 696 // retry loop. 697 *bits |= 0x00020000; 698 return false; 699 } 700 701 if (is_suspended) { 702 *bits |= 0x00040000; 703 return true; 704 } 705 706 for (int i = 1; i <= retries; i++) { 707 *bits = reset_bits; // reinit to only track last retry 708 709 // We used to do an "os::yield_all(i)" call here with the intention 710 // that yielding would increase on each retry. However, the parameter 711 // is ignored on Linux which means the yield didn't scale up. Waiting 712 // on the SR_lock below provides a much more predictable scale up for 713 // the delay. It also provides a simple/direct point to check for any 714 // safepoint requests from the VMThread 715 716 { 717 MutexLocker ml(SR_lock()); 718 // wait with safepoint check (if we're a JavaThread - the WatcherThread 719 // can also call this) and increase delay with each retry 720 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 721 722 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 723 delay, bits); 724 725 // It is possible for the external suspend request to be cancelled 726 // (by a resume) before the actual suspend operation is completed. 727 // Refresh our local copy to see if we still need to wait. 728 pending = is_external_suspend(); 729 } 730 731 if (!pending) { 732 // A cancelled suspend request is the only false return from 733 // is_ext_suspend_completed() that keeps us from staying in the 734 // retry loop. 735 *bits |= 0x00080000; 736 return false; 737 } 738 739 if (is_suspended) { 740 *bits |= 0x00100000; 741 return true; 742 } 743 } // end retry loop 744 745 // thread did not suspend after all our retries 746 *bits |= 0x00200000; 747 return false; 748 } 749 750 #ifndef PRODUCT 751 void JavaThread::record_jump(address target, address instr, const char* file, int line) { 752 753 // This should not need to be atomic as the only way for simultaneous 754 // updates is via interrupts. Even then this should be rare or non-existent 755 // and we don't care that much anyway. 756 757 int index = _jmp_ring_index; 758 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 759 _jmp_ring[index]._target = (intptr_t) target; 760 _jmp_ring[index]._instruction = (intptr_t) instr; 761 _jmp_ring[index]._file = file; 762 _jmp_ring[index]._line = line; 763 } 764 #endif /* PRODUCT */ 765 766 // Called by flat profiler 767 // Callers have already called wait_for_ext_suspend_completion 768 // The assertion for that is currently too complex to put here: 769 bool JavaThread::profile_last_Java_frame(frame* _fr) { 770 bool gotframe = false; 771 // self suspension saves needed state. 772 if (has_last_Java_frame() && _anchor.walkable()) { 773 *_fr = pd_last_frame(); 774 gotframe = true; 775 } 776 return gotframe; 777 } 778 779 void Thread::interrupt(Thread* thread) { 780 trace("interrupt", thread); 781 debug_only(check_for_dangling_thread_pointer(thread);) 782 os::interrupt(thread); 783 } 784 785 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 786 trace("is_interrupted", thread); 787 debug_only(check_for_dangling_thread_pointer(thread);) 788 // Note: If clear_interrupted==false, this simply fetches and 789 // returns the value of the field osthread()->interrupted(). 790 return os::is_interrupted(thread, clear_interrupted); 791 } 792 793 794 // GC Support 795 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 796 jint thread_parity = _oops_do_parity; 797 if (thread_parity != strong_roots_parity) { 798 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 799 if (res == thread_parity) { 800 return true; 801 } else { 802 guarantee(res == strong_roots_parity, "Or else what?"); 803 assert(SharedHeap::heap()->workers()->active_workers() > 0, 804 "Should only fail when parallel."); 805 return false; 806 } 807 } 808 assert(SharedHeap::heap()->workers()->active_workers() > 0, 809 "Should only fail when parallel."); 810 return false; 811 } 812 813 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 814 active_handles()->oops_do(f); 815 // Do oop for ThreadShadow 816 f->do_oop((oop*)&_pending_exception); 817 handle_area()->oops_do(f); 818 } 819 820 void Thread::nmethods_do(CodeBlobClosure* cf) { 821 // no nmethods in a generic thread... 822 } 823 824 void Thread::metadata_do(void f(Metadata*)) { 825 if (metadata_handles() != NULL) { 826 for (int i = 0; i< metadata_handles()->length(); i++) { 827 f(metadata_handles()->at(i)); 828 } 829 } 830 } 831 832 void Thread::print_on(outputStream* st) const { 833 // get_priority assumes osthread initialized 834 if (osthread() != NULL) { 835 int os_prio; 836 if (os::get_native_priority(this, &os_prio) == OS_OK) { 837 st->print("os_prio=%d ", os_prio); 838 } 839 st->print("tid=" INTPTR_FORMAT " ", this); 840 osthread()->print_on(st); 841 } 842 debug_only(if (WizardMode) print_owned_locks_on(st);) 843 } 844 845 // Thread::print_on_error() is called by fatal error handler. Don't use 846 // any lock or allocate memory. 847 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 848 if (is_VM_thread()) st->print("VMThread"); 849 else if (is_Compiler_thread()) st->print("CompilerThread"); 850 else if (is_Java_thread()) st->print("JavaThread"); 851 else if (is_GC_task_thread()) st->print("GCTaskThread"); 852 else if (is_Watcher_thread()) st->print("WatcherThread"); 853 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 854 else st->print("Thread"); 855 856 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 857 _stack_base - _stack_size, _stack_base); 858 859 if (osthread()) { 860 st->print(" [id=%d]", osthread()->thread_id()); 861 } 862 } 863 864 #ifdef ASSERT 865 void Thread::print_owned_locks_on(outputStream* st) const { 866 Monitor *cur = _owned_locks; 867 if (cur == NULL) { 868 st->print(" (no locks) "); 869 } else { 870 st->print_cr(" Locks owned:"); 871 while (cur) { 872 cur->print_on(st); 873 cur = cur->next(); 874 } 875 } 876 } 877 878 static int ref_use_count = 0; 879 880 bool Thread::owns_locks_but_compiled_lock() const { 881 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 882 if (cur != Compile_lock) return true; 883 } 884 return false; 885 } 886 887 888 #endif 889 890 #ifndef PRODUCT 891 892 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 893 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 894 // no threads which allow_vm_block's are held 895 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 896 // Check if current thread is allowed to block at a safepoint 897 if (!(_allow_safepoint_count == 0)) 898 fatal("Possible safepoint reached by thread that does not allow it"); 899 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 900 fatal("LEAF method calling lock?"); 901 } 902 903 #ifdef ASSERT 904 if (potential_vm_operation && is_Java_thread() 905 && !Universe::is_bootstrapping()) { 906 // Make sure we do not hold any locks that the VM thread also uses. 907 // This could potentially lead to deadlocks 908 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 909 // Threads_lock is special, since the safepoint synchronization will not start before this is 910 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 911 // since it is used to transfer control between JavaThreads and the VMThread 912 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 913 if ((cur->allow_vm_block() && 914 cur != Threads_lock && 915 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 916 cur != VMOperationRequest_lock && 917 cur != VMOperationQueue_lock) || 918 cur->rank() == Mutex::special) { 919 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name())); 920 } 921 } 922 } 923 924 if (GCALotAtAllSafepoints) { 925 // We could enter a safepoint here and thus have a gc 926 InterfaceSupport::check_gc_alot(); 927 } 928 #endif 929 } 930 #endif 931 932 bool Thread::is_in_stack(address adr) const { 933 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 934 address end = os::current_stack_pointer(); 935 // Allow non Java threads to call this without stack_base 936 if (_stack_base == NULL) return true; 937 if (stack_base() >= adr && adr >= end) return true; 938 939 return false; 940 } 941 942 943 bool Thread::is_in_usable_stack(address adr) const { 944 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 945 size_t usable_stack_size = _stack_size - stack_guard_size; 946 947 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 948 } 949 950 951 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 952 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 953 // used for compilation in the future. If that change is made, the need for these methods 954 // should be revisited, and they should be removed if possible. 955 956 bool Thread::is_lock_owned(address adr) const { 957 return on_local_stack(adr); 958 } 959 960 bool Thread::set_as_starting_thread() { 961 // NOTE: this must be called inside the main thread. 962 return os::create_main_thread((JavaThread*)this); 963 } 964 965 static void initialize_class(Symbol* class_name, TRAPS) { 966 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 967 InstanceKlass::cast(klass)->initialize(CHECK); 968 } 969 970 971 // Creates the initial ThreadGroup 972 static Handle create_initial_thread_group(TRAPS) { 973 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 974 instanceKlassHandle klass (THREAD, k); 975 976 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 977 { 978 JavaValue result(T_VOID); 979 JavaCalls::call_special(&result, 980 system_instance, 981 klass, 982 vmSymbols::object_initializer_name(), 983 vmSymbols::void_method_signature(), 984 CHECK_NH); 985 } 986 Universe::set_system_thread_group(system_instance()); 987 988 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 989 { 990 JavaValue result(T_VOID); 991 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 992 JavaCalls::call_special(&result, 993 main_instance, 994 klass, 995 vmSymbols::object_initializer_name(), 996 vmSymbols::threadgroup_string_void_signature(), 997 system_instance, 998 string, 999 CHECK_NH); 1000 } 1001 return main_instance; 1002 } 1003 1004 // Creates the initial Thread 1005 static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1006 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1007 instanceKlassHandle klass (THREAD, k); 1008 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1009 1010 java_lang_Thread::set_thread(thread_oop(), thread); 1011 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1012 thread->set_threadObj(thread_oop()); 1013 1014 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1015 1016 JavaValue result(T_VOID); 1017 JavaCalls::call_special(&result, thread_oop, 1018 klass, 1019 vmSymbols::object_initializer_name(), 1020 vmSymbols::threadgroup_string_void_signature(), 1021 thread_group, 1022 string, 1023 CHECK_NULL); 1024 return thread_oop(); 1025 } 1026 1027 static void call_initializeSystemClass(TRAPS) { 1028 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1029 instanceKlassHandle klass (THREAD, k); 1030 1031 JavaValue result(T_VOID); 1032 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1033 vmSymbols::void_method_signature(), CHECK); 1034 } 1035 1036 char java_runtime_name[128] = ""; 1037 char java_runtime_version[128] = ""; 1038 1039 // extract the JRE name from sun.misc.Version.java_runtime_name 1040 static const char* get_java_runtime_name(TRAPS) { 1041 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1042 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1043 fieldDescriptor fd; 1044 bool found = k != NULL && 1045 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1046 vmSymbols::string_signature(), &fd); 1047 if (found) { 1048 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1049 if (name_oop == NULL) 1050 return NULL; 1051 const char* name = java_lang_String::as_utf8_string(name_oop, 1052 java_runtime_name, 1053 sizeof(java_runtime_name)); 1054 return name; 1055 } else { 1056 return NULL; 1057 } 1058 } 1059 1060 // extract the JRE version from sun.misc.Version.java_runtime_version 1061 static const char* get_java_runtime_version(TRAPS) { 1062 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1063 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1064 fieldDescriptor fd; 1065 bool found = k != NULL && 1066 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1067 vmSymbols::string_signature(), &fd); 1068 if (found) { 1069 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1070 if (name_oop == NULL) 1071 return NULL; 1072 const char* name = java_lang_String::as_utf8_string(name_oop, 1073 java_runtime_version, 1074 sizeof(java_runtime_version)); 1075 return name; 1076 } else { 1077 return NULL; 1078 } 1079 } 1080 1081 // General purpose hook into Java code, run once when the VM is initialized. 1082 // The Java library method itself may be changed independently from the VM. 1083 static void call_postVMInitHook(TRAPS) { 1084 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1085 instanceKlassHandle klass (THREAD, k); 1086 if (klass.not_null()) { 1087 JavaValue result(T_VOID); 1088 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1089 vmSymbols::void_method_signature(), 1090 CHECK); 1091 } 1092 } 1093 1094 static void reset_vm_info_property(TRAPS) { 1095 // the vm info string 1096 ResourceMark rm(THREAD); 1097 const char *vm_info = VM_Version::vm_info_string(); 1098 1099 // java.lang.System class 1100 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1101 instanceKlassHandle klass (THREAD, k); 1102 1103 // setProperty arguments 1104 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1105 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1106 1107 // return value 1108 JavaValue r(T_OBJECT); 1109 1110 // public static String setProperty(String key, String value); 1111 JavaCalls::call_static(&r, 1112 klass, 1113 vmSymbols::setProperty_name(), 1114 vmSymbols::string_string_string_signature(), 1115 key_str, 1116 value_str, 1117 CHECK); 1118 } 1119 1120 1121 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1122 assert(thread_group.not_null(), "thread group should be specified"); 1123 assert(threadObj() == NULL, "should only create Java thread object once"); 1124 1125 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1126 instanceKlassHandle klass (THREAD, k); 1127 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1128 1129 java_lang_Thread::set_thread(thread_oop(), this); 1130 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1131 set_threadObj(thread_oop()); 1132 1133 JavaValue result(T_VOID); 1134 if (thread_name != NULL) { 1135 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1136 // Thread gets assigned specified name and null target 1137 JavaCalls::call_special(&result, 1138 thread_oop, 1139 klass, 1140 vmSymbols::object_initializer_name(), 1141 vmSymbols::threadgroup_string_void_signature(), 1142 thread_group, // Argument 1 1143 name, // Argument 2 1144 THREAD); 1145 } else { 1146 // Thread gets assigned name "Thread-nnn" and null target 1147 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1148 JavaCalls::call_special(&result, 1149 thread_oop, 1150 klass, 1151 vmSymbols::object_initializer_name(), 1152 vmSymbols::threadgroup_runnable_void_signature(), 1153 thread_group, // Argument 1 1154 Handle(), // Argument 2 1155 THREAD); 1156 } 1157 1158 1159 if (daemon) { 1160 java_lang_Thread::set_daemon(thread_oop()); 1161 } 1162 1163 if (HAS_PENDING_EXCEPTION) { 1164 return; 1165 } 1166 1167 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1168 Handle threadObj(this, this->threadObj()); 1169 1170 JavaCalls::call_special(&result, 1171 thread_group, 1172 group, 1173 vmSymbols::add_method_name(), 1174 vmSymbols::thread_void_signature(), 1175 threadObj, // Arg 1 1176 THREAD); 1177 1178 1179 } 1180 1181 // NamedThread -- non-JavaThread subclasses with multiple 1182 // uniquely named instances should derive from this. 1183 NamedThread::NamedThread() : Thread() { 1184 _name = NULL; 1185 _processed_thread = NULL; 1186 } 1187 1188 NamedThread::~NamedThread() { 1189 if (_name != NULL) { 1190 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1191 _name = NULL; 1192 } 1193 } 1194 1195 void NamedThread::set_name(const char* format, ...) { 1196 guarantee(_name == NULL, "Only get to set name once."); 1197 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1198 guarantee(_name != NULL, "alloc failure"); 1199 va_list ap; 1200 va_start(ap, format); 1201 jio_vsnprintf(_name, max_name_len, format, ap); 1202 va_end(ap); 1203 } 1204 1205 void NamedThread::print_on(outputStream* st) const { 1206 st->print("\"%s\" ", name()); 1207 Thread::print_on(st); 1208 st->cr(); 1209 } 1210 1211 1212 // ======= WatcherThread ======== 1213 1214 // The watcher thread exists to simulate timer interrupts. It should 1215 // be replaced by an abstraction over whatever native support for 1216 // timer interrupts exists on the platform. 1217 1218 WatcherThread* WatcherThread::_watcher_thread = NULL; 1219 bool WatcherThread::_startable = false; 1220 volatile bool WatcherThread::_should_terminate = false; 1221 1222 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1223 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1224 if (os::create_thread(this, os::watcher_thread)) { 1225 _watcher_thread = this; 1226 1227 // Set the watcher thread to the highest OS priority which should not be 1228 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1229 // is created. The only normal thread using this priority is the reference 1230 // handler thread, which runs for very short intervals only. 1231 // If the VMThread's priority is not lower than the WatcherThread profiling 1232 // will be inaccurate. 1233 os::set_priority(this, MaxPriority); 1234 if (!DisableStartThread) { 1235 os::start_thread(this); 1236 } 1237 } 1238 } 1239 1240 int WatcherThread::sleep() const { 1241 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1242 1243 // remaining will be zero if there are no tasks, 1244 // causing the WatcherThread to sleep until a task is 1245 // enrolled 1246 int remaining = PeriodicTask::time_to_wait(); 1247 int time_slept = 0; 1248 1249 // we expect this to timeout - we only ever get unparked when 1250 // we should terminate or when a new task has been enrolled 1251 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1252 1253 jlong time_before_loop = os::javaTimeNanos(); 1254 1255 for (;;) { 1256 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1257 jlong now = os::javaTimeNanos(); 1258 1259 if (remaining == 0) { 1260 // if we didn't have any tasks we could have waited for a long time 1261 // consider the time_slept zero and reset time_before_loop 1262 time_slept = 0; 1263 time_before_loop = now; 1264 } else { 1265 // need to recalculate since we might have new tasks in _tasks 1266 time_slept = (int) ((now - time_before_loop) / 1000000); 1267 } 1268 1269 // Change to task list or spurious wakeup of some kind 1270 if (timedout || _should_terminate) { 1271 break; 1272 } 1273 1274 remaining = PeriodicTask::time_to_wait(); 1275 if (remaining == 0) { 1276 // Last task was just disenrolled so loop around and wait until 1277 // another task gets enrolled 1278 continue; 1279 } 1280 1281 remaining -= time_slept; 1282 if (remaining <= 0) 1283 break; 1284 } 1285 1286 return time_slept; 1287 } 1288 1289 void WatcherThread::run() { 1290 assert(this == watcher_thread(), "just checking"); 1291 1292 this->record_stack_base_and_size(); 1293 this->initialize_thread_local_storage(); 1294 this->set_active_handles(JNIHandleBlock::allocate_block()); 1295 while (!_should_terminate) { 1296 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1297 assert(watcher_thread() == this, "thread consistency check"); 1298 1299 // Calculate how long it'll be until the next PeriodicTask work 1300 // should be done, and sleep that amount of time. 1301 int time_waited = sleep(); 1302 1303 if (is_error_reported()) { 1304 // A fatal error has happened, the error handler(VMError::report_and_die) 1305 // should abort JVM after creating an error log file. However in some 1306 // rare cases, the error handler itself might deadlock. Here we try to 1307 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1308 // 1309 // This code is in WatcherThread because WatcherThread wakes up 1310 // periodically so the fatal error handler doesn't need to do anything; 1311 // also because the WatcherThread is less likely to crash than other 1312 // threads. 1313 1314 for (;;) { 1315 if (!ShowMessageBoxOnError 1316 && (OnError == NULL || OnError[0] == '\0') 1317 && Arguments::abort_hook() == NULL) { 1318 os::sleep(this, 2 * 60 * 1000, false); 1319 fdStream err(defaultStream::output_fd()); 1320 err.print_raw_cr("# [ timer expired, abort... ]"); 1321 // skip atexit/vm_exit/vm_abort hooks 1322 os::die(); 1323 } 1324 1325 // Wake up 5 seconds later, the fatal handler may reset OnError or 1326 // ShowMessageBoxOnError when it is ready to abort. 1327 os::sleep(this, 5 * 1000, false); 1328 } 1329 } 1330 1331 PeriodicTask::real_time_tick(time_waited); 1332 } 1333 1334 // Signal that it is terminated 1335 { 1336 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1337 _watcher_thread = NULL; 1338 Terminator_lock->notify(); 1339 } 1340 1341 // Thread destructor usually does this.. 1342 ThreadLocalStorage::set_thread(NULL); 1343 } 1344 1345 void WatcherThread::start() { 1346 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1347 1348 if (watcher_thread() == NULL && _startable) { 1349 _should_terminate = false; 1350 // Create the single instance of WatcherThread 1351 new WatcherThread(); 1352 } 1353 } 1354 1355 void WatcherThread::make_startable() { 1356 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1357 _startable = true; 1358 } 1359 1360 void WatcherThread::stop() { 1361 { 1362 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1363 _should_terminate = true; 1364 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1365 1366 WatcherThread* watcher = watcher_thread(); 1367 if (watcher != NULL) 1368 watcher->unpark(); 1369 } 1370 1371 // it is ok to take late safepoints here, if needed 1372 MutexLocker mu(Terminator_lock); 1373 1374 while (watcher_thread() != NULL) { 1375 // This wait should make safepoint checks, wait without a timeout, 1376 // and wait as a suspend-equivalent condition. 1377 // 1378 // Note: If the FlatProfiler is running, then this thread is waiting 1379 // for the WatcherThread to terminate and the WatcherThread, via the 1380 // FlatProfiler task, is waiting for the external suspend request on 1381 // this thread to complete. wait_for_ext_suspend_completion() will 1382 // eventually timeout, but that takes time. Making this wait a 1383 // suspend-equivalent condition solves that timeout problem. 1384 // 1385 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1386 Mutex::_as_suspend_equivalent_flag); 1387 } 1388 } 1389 1390 void WatcherThread::unpark() { 1391 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1392 PeriodicTask_lock->notify(); 1393 } 1394 1395 void WatcherThread::print_on(outputStream* st) const { 1396 st->print("\"%s\" ", name()); 1397 Thread::print_on(st); 1398 st->cr(); 1399 } 1400 1401 // ======= JavaThread ======== 1402 1403 // A JavaThread is a normal Java thread 1404 1405 void JavaThread::initialize() { 1406 // Initialize fields 1407 1408 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1409 set_claimed_par_id(UINT_MAX); 1410 1411 set_saved_exception_pc(NULL); 1412 set_threadObj(NULL); 1413 _anchor.clear(); 1414 set_entry_point(NULL); 1415 set_jni_functions(jni_functions()); 1416 set_callee_target(NULL); 1417 set_vm_result(NULL); 1418 set_vm_result_2(NULL); 1419 set_vframe_array_head(NULL); 1420 set_vframe_array_last(NULL); 1421 set_deferred_locals(NULL); 1422 set_deopt_mark(NULL); 1423 set_deopt_nmethod(NULL); 1424 clear_must_deopt_id(); 1425 set_monitor_chunks(NULL); 1426 set_next(NULL); 1427 set_thread_state(_thread_new); 1428 #if INCLUDE_NMT 1429 set_recorder(NULL); 1430 #endif 1431 _terminated = _not_terminated; 1432 _privileged_stack_top = NULL; 1433 _array_for_gc = NULL; 1434 _suspend_equivalent = false; 1435 _in_deopt_handler = 0; 1436 _doing_unsafe_access = false; 1437 _stack_guard_state = stack_guard_unused; 1438 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1439 _exception_pc = 0; 1440 _exception_handler_pc = 0; 1441 _is_method_handle_return = 0; 1442 _jvmti_thread_state= NULL; 1443 _should_post_on_exceptions_flag = JNI_FALSE; 1444 _jvmti_get_loaded_classes_closure = NULL; 1445 _interp_only_mode = 0; 1446 _special_runtime_exit_condition = _no_async_condition; 1447 _pending_async_exception = NULL; 1448 _thread_stat = NULL; 1449 _thread_stat = new ThreadStatistics(); 1450 _blocked_on_compilation = false; 1451 _jni_active_critical = 0; 1452 _pending_jni_exception_check_fn = NULL; 1453 _do_not_unlock_if_synchronized = false; 1454 _cached_monitor_info = NULL; 1455 _parker = Parker::Allocate(this); 1456 1457 #ifndef PRODUCT 1458 _jmp_ring_index = 0; 1459 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1460 record_jump(NULL, NULL, NULL, 0); 1461 } 1462 #endif /* PRODUCT */ 1463 1464 set_thread_profiler(NULL); 1465 if (FlatProfiler::is_active()) { 1466 // This is where we would decide to either give each thread it's own profiler 1467 // or use one global one from FlatProfiler, 1468 // or up to some count of the number of profiled threads, etc. 1469 ThreadProfiler* pp = new ThreadProfiler(); 1470 pp->engage(); 1471 set_thread_profiler(pp); 1472 } 1473 1474 // Setup safepoint state info for this thread 1475 ThreadSafepointState::create(this); 1476 1477 debug_only(_java_call_counter = 0); 1478 1479 // JVMTI PopFrame support 1480 _popframe_condition = popframe_inactive; 1481 _popframe_preserved_args = NULL; 1482 _popframe_preserved_args_size = 0; 1483 1484 pd_initialize(); 1485 } 1486 1487 #if INCLUDE_ALL_GCS 1488 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1489 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1490 #endif // INCLUDE_ALL_GCS 1491 1492 JavaThread::JavaThread(bool is_attaching_via_jni) : 1493 Thread() 1494 #if INCLUDE_ALL_GCS 1495 , _satb_mark_queue(&_satb_mark_queue_set), 1496 _dirty_card_queue(&_dirty_card_queue_set) 1497 #endif // INCLUDE_ALL_GCS 1498 { 1499 initialize(); 1500 if (is_attaching_via_jni) { 1501 _jni_attach_state = _attaching_via_jni; 1502 } else { 1503 _jni_attach_state = _not_attaching_via_jni; 1504 } 1505 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1506 _safepoint_visible = false; 1507 } 1508 1509 bool JavaThread::reguard_stack(address cur_sp) { 1510 if (_stack_guard_state != stack_guard_yellow_disabled) { 1511 return true; // Stack already guarded or guard pages not needed. 1512 } 1513 1514 if (register_stack_overflow()) { 1515 // For those architectures which have separate register and 1516 // memory stacks, we must check the register stack to see if 1517 // it has overflowed. 1518 return false; 1519 } 1520 1521 // Java code never executes within the yellow zone: the latter is only 1522 // there to provoke an exception during stack banging. If java code 1523 // is executing there, either StackShadowPages should be larger, or 1524 // some exception code in c1, c2 or the interpreter isn't unwinding 1525 // when it should. 1526 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1527 1528 enable_stack_yellow_zone(); 1529 return true; 1530 } 1531 1532 bool JavaThread::reguard_stack(void) { 1533 return reguard_stack(os::current_stack_pointer()); 1534 } 1535 1536 1537 void JavaThread::block_if_vm_exited() { 1538 if (_terminated == _vm_exited) { 1539 // _vm_exited is set at safepoint, and Threads_lock is never released 1540 // we will block here forever 1541 Threads_lock->lock_without_safepoint_check(); 1542 ShouldNotReachHere(); 1543 } 1544 } 1545 1546 1547 // Remove this ifdef when C1 is ported to the compiler interface. 1548 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1549 1550 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1551 Thread() 1552 #if INCLUDE_ALL_GCS 1553 , _satb_mark_queue(&_satb_mark_queue_set), 1554 _dirty_card_queue(&_dirty_card_queue_set) 1555 #endif // INCLUDE_ALL_GCS 1556 { 1557 if (TraceThreadEvents) { 1558 tty->print_cr("creating thread %p", this); 1559 } 1560 initialize(); 1561 _jni_attach_state = _not_attaching_via_jni; 1562 set_entry_point(entry_point); 1563 // Create the native thread itself. 1564 // %note runtime_23 1565 os::ThreadType thr_type = os::java_thread; 1566 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1567 os::java_thread; 1568 os::create_thread(this, thr_type, stack_sz); 1569 _safepoint_visible = false; 1570 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1571 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1572 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1573 // the exception consists of creating the exception object & initializing it, initialization 1574 // will leave the VM via a JavaCall and then all locks must be unlocked). 1575 // 1576 // The thread is still suspended when we reach here. Thread must be explicit started 1577 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1578 // by calling Threads:add. The reason why this is not done here, is because the thread 1579 // object must be fully initialized (take a look at JVM_Start) 1580 } 1581 1582 JavaThread::~JavaThread() { 1583 if (TraceThreadEvents) { 1584 tty->print_cr("terminate thread %p", this); 1585 } 1586 1587 // By now, this thread should already be invisible to safepoint, 1588 // and its per-thread recorder also collected. 1589 assert(!is_safepoint_visible(), "wrong state"); 1590 #if INCLUDE_NMT 1591 assert(get_recorder() == NULL, "Already collected"); 1592 #endif // INCLUDE_NMT 1593 1594 // JSR166 -- return the parker to the free list 1595 Parker::Release(_parker); 1596 _parker = NULL; 1597 1598 // Free any remaining previous UnrollBlock 1599 vframeArray* old_array = vframe_array_last(); 1600 1601 if (old_array != NULL) { 1602 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1603 old_array->set_unroll_block(NULL); 1604 delete old_info; 1605 delete old_array; 1606 } 1607 1608 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1609 if (deferred != NULL) { 1610 // This can only happen if thread is destroyed before deoptimization occurs. 1611 assert(deferred->length() != 0, "empty array!"); 1612 do { 1613 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1614 deferred->remove_at(0); 1615 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1616 delete dlv; 1617 } while (deferred->length() != 0); 1618 delete deferred; 1619 } 1620 1621 // All Java related clean up happens in exit 1622 ThreadSafepointState::destroy(this); 1623 if (_thread_profiler != NULL) delete _thread_profiler; 1624 if (_thread_stat != NULL) delete _thread_stat; 1625 } 1626 1627 1628 // The first routine called by a new Java thread 1629 void JavaThread::run() { 1630 // initialize thread-local alloc buffer related fields 1631 this->initialize_tlab(); 1632 1633 // used to test validity of stack trace backs 1634 this->record_base_of_stack_pointer(); 1635 1636 // Record real stack base and size. 1637 this->record_stack_base_and_size(); 1638 1639 // Initialize thread local storage; set before calling MutexLocker 1640 this->initialize_thread_local_storage(); 1641 1642 this->create_stack_guard_pages(); 1643 1644 this->cache_global_variables(); 1645 1646 // Thread is now sufficient initialized to be handled by the safepoint code as being 1647 // in the VM. Change thread state from _thread_new to _thread_in_vm 1648 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1649 1650 assert(JavaThread::current() == this, "sanity check"); 1651 assert(!Thread::current()->owns_locks(), "sanity check"); 1652 1653 DTRACE_THREAD_PROBE(start, this); 1654 1655 // This operation might block. We call that after all safepoint checks for a new thread has 1656 // been completed. 1657 this->set_active_handles(JNIHandleBlock::allocate_block()); 1658 1659 if (JvmtiExport::should_post_thread_life()) { 1660 JvmtiExport::post_thread_start(this); 1661 } 1662 1663 EventThreadStart event; 1664 if (event.should_commit()) { 1665 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1666 event.commit(); 1667 } 1668 1669 // We call another function to do the rest so we are sure that the stack addresses used 1670 // from there will be lower than the stack base just computed 1671 thread_main_inner(); 1672 1673 // Note, thread is no longer valid at this point! 1674 } 1675 1676 1677 void JavaThread::thread_main_inner() { 1678 assert(JavaThread::current() == this, "sanity check"); 1679 assert(this->threadObj() != NULL, "just checking"); 1680 1681 // Execute thread entry point unless this thread has a pending exception 1682 // or has been stopped before starting. 1683 // Note: Due to JVM_StopThread we can have pending exceptions already! 1684 if (!this->has_pending_exception() && 1685 !java_lang_Thread::is_stillborn(this->threadObj())) { 1686 { 1687 ResourceMark rm(this); 1688 this->set_native_thread_name(this->get_thread_name()); 1689 } 1690 HandleMark hm(this); 1691 this->entry_point()(this, this); 1692 } 1693 1694 DTRACE_THREAD_PROBE(stop, this); 1695 1696 this->exit(false); 1697 delete this; 1698 } 1699 1700 1701 static void ensure_join(JavaThread* thread) { 1702 // We do not need to grap the Threads_lock, since we are operating on ourself. 1703 Handle threadObj(thread, thread->threadObj()); 1704 assert(threadObj.not_null(), "java thread object must exist"); 1705 ObjectLocker lock(threadObj, thread); 1706 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1707 thread->clear_pending_exception(); 1708 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1709 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1710 // Clear the native thread instance - this makes isAlive return false and allows the join() 1711 // to complete once we've done the notify_all below 1712 java_lang_Thread::set_thread(threadObj(), NULL); 1713 lock.notify_all(thread); 1714 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1715 thread->clear_pending_exception(); 1716 } 1717 1718 1719 // For any new cleanup additions, please check to see if they need to be applied to 1720 // cleanup_failed_attach_current_thread as well. 1721 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1722 assert(this == JavaThread::current(), "thread consistency check"); 1723 1724 HandleMark hm(this); 1725 Handle uncaught_exception(this, this->pending_exception()); 1726 this->clear_pending_exception(); 1727 Handle threadObj(this, this->threadObj()); 1728 assert(threadObj.not_null(), "Java thread object should be created"); 1729 1730 if (get_thread_profiler() != NULL) { 1731 get_thread_profiler()->disengage(); 1732 ResourceMark rm; 1733 get_thread_profiler()->print(get_thread_name()); 1734 } 1735 1736 1737 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1738 { 1739 EXCEPTION_MARK; 1740 1741 CLEAR_PENDING_EXCEPTION; 1742 } 1743 if (!destroy_vm) { 1744 if (uncaught_exception.not_null()) { 1745 EXCEPTION_MARK; 1746 // Call method Thread.dispatchUncaughtException(). 1747 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1748 JavaValue result(T_VOID); 1749 JavaCalls::call_virtual(&result, 1750 threadObj, thread_klass, 1751 vmSymbols::dispatchUncaughtException_name(), 1752 vmSymbols::throwable_void_signature(), 1753 uncaught_exception, 1754 THREAD); 1755 if (HAS_PENDING_EXCEPTION) { 1756 ResourceMark rm(this); 1757 jio_fprintf(defaultStream::error_stream(), 1758 "\nException: %s thrown from the UncaughtExceptionHandler" 1759 " in thread \"%s\"\n", 1760 pending_exception()->klass()->external_name(), 1761 get_thread_name()); 1762 CLEAR_PENDING_EXCEPTION; 1763 } 1764 } 1765 1766 // Called before the java thread exit since we want to read info 1767 // from java_lang_Thread object 1768 EventThreadEnd event; 1769 if (event.should_commit()) { 1770 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1771 event.commit(); 1772 } 1773 1774 // Call after last event on thread 1775 EVENT_THREAD_EXIT(this); 1776 1777 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1778 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1779 // is deprecated anyhow. 1780 if (!is_Compiler_thread()) { 1781 int count = 3; 1782 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1783 EXCEPTION_MARK; 1784 JavaValue result(T_VOID); 1785 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1786 JavaCalls::call_virtual(&result, 1787 threadObj, thread_klass, 1788 vmSymbols::exit_method_name(), 1789 vmSymbols::void_method_signature(), 1790 THREAD); 1791 CLEAR_PENDING_EXCEPTION; 1792 } 1793 } 1794 // notify JVMTI 1795 if (JvmtiExport::should_post_thread_life()) { 1796 JvmtiExport::post_thread_end(this); 1797 } 1798 1799 // We have notified the agents that we are exiting, before we go on, 1800 // we must check for a pending external suspend request and honor it 1801 // in order to not surprise the thread that made the suspend request. 1802 while (true) { 1803 { 1804 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1805 if (!is_external_suspend()) { 1806 set_terminated(_thread_exiting); 1807 ThreadService::current_thread_exiting(this); 1808 break; 1809 } 1810 // Implied else: 1811 // Things get a little tricky here. We have a pending external 1812 // suspend request, but we are holding the SR_lock so we 1813 // can't just self-suspend. So we temporarily drop the lock 1814 // and then self-suspend. 1815 } 1816 1817 ThreadBlockInVM tbivm(this); 1818 java_suspend_self(); 1819 1820 // We're done with this suspend request, but we have to loop around 1821 // and check again. Eventually we will get SR_lock without a pending 1822 // external suspend request and will be able to mark ourselves as 1823 // exiting. 1824 } 1825 // no more external suspends are allowed at this point 1826 } else { 1827 // before_exit() has already posted JVMTI THREAD_END events 1828 } 1829 1830 // Notify waiters on thread object. This has to be done after exit() is called 1831 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1832 // group should have the destroyed bit set before waiters are notified). 1833 ensure_join(this); 1834 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1835 1836 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1837 // held by this thread must be released. A detach operation must only 1838 // get here if there are no Java frames on the stack. Therefore, any 1839 // owned monitors at this point MUST be JNI-acquired monitors which are 1840 // pre-inflated and in the monitor cache. 1841 // 1842 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1843 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1844 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1845 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1846 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1847 } 1848 1849 // These things needs to be done while we are still a Java Thread. Make sure that thread 1850 // is in a consistent state, in case GC happens 1851 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1852 1853 if (active_handles() != NULL) { 1854 JNIHandleBlock* block = active_handles(); 1855 set_active_handles(NULL); 1856 JNIHandleBlock::release_block(block); 1857 } 1858 1859 if (free_handle_block() != NULL) { 1860 JNIHandleBlock* block = free_handle_block(); 1861 set_free_handle_block(NULL); 1862 JNIHandleBlock::release_block(block); 1863 } 1864 1865 // These have to be removed while this is still a valid thread. 1866 remove_stack_guard_pages(); 1867 1868 if (UseTLAB) { 1869 tlab().make_parsable(true); // retire TLAB 1870 } 1871 1872 if (JvmtiEnv::environments_might_exist()) { 1873 JvmtiExport::cleanup_thread(this); 1874 } 1875 1876 // We must flush any deferred card marks before removing a thread from 1877 // the list of active threads. 1878 Universe::heap()->flush_deferred_store_barrier(this); 1879 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1880 1881 #if INCLUDE_ALL_GCS 1882 // We must flush the G1-related buffers before removing a thread 1883 // from the list of active threads. We must do this after any deferred 1884 // card marks have been flushed (above) so that any entries that are 1885 // added to the thread's dirty card queue as a result are not lost. 1886 if (UseG1GC) { 1887 flush_barrier_queues(); 1888 } 1889 #endif // INCLUDE_ALL_GCS 1890 1891 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1892 Threads::remove(this); 1893 } 1894 1895 #if INCLUDE_ALL_GCS 1896 // Flush G1-related queues. 1897 void JavaThread::flush_barrier_queues() { 1898 satb_mark_queue().flush(); 1899 dirty_card_queue().flush(); 1900 } 1901 1902 void JavaThread::initialize_queues() { 1903 assert(!SafepointSynchronize::is_at_safepoint(), 1904 "we should not be at a safepoint"); 1905 1906 ObjPtrQueue& satb_queue = satb_mark_queue(); 1907 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1908 // The SATB queue should have been constructed with its active 1909 // field set to false. 1910 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1911 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1912 // If we are creating the thread during a marking cycle, we should 1913 // set the active field of the SATB queue to true. 1914 if (satb_queue_set.is_active()) { 1915 satb_queue.set_active(true); 1916 } 1917 1918 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1919 // The dirty card queue should have been constructed with its 1920 // active field set to true. 1921 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1922 } 1923 #endif // INCLUDE_ALL_GCS 1924 1925 void JavaThread::cleanup_failed_attach_current_thread() { 1926 if (get_thread_profiler() != NULL) { 1927 get_thread_profiler()->disengage(); 1928 ResourceMark rm; 1929 get_thread_profiler()->print(get_thread_name()); 1930 } 1931 1932 if (active_handles() != NULL) { 1933 JNIHandleBlock* block = active_handles(); 1934 set_active_handles(NULL); 1935 JNIHandleBlock::release_block(block); 1936 } 1937 1938 if (free_handle_block() != NULL) { 1939 JNIHandleBlock* block = free_handle_block(); 1940 set_free_handle_block(NULL); 1941 JNIHandleBlock::release_block(block); 1942 } 1943 1944 // These have to be removed while this is still a valid thread. 1945 remove_stack_guard_pages(); 1946 1947 if (UseTLAB) { 1948 tlab().make_parsable(true); // retire TLAB, if any 1949 } 1950 1951 #if INCLUDE_ALL_GCS 1952 if (UseG1GC) { 1953 flush_barrier_queues(); 1954 } 1955 #endif // INCLUDE_ALL_GCS 1956 1957 Threads::remove(this); 1958 delete this; 1959 } 1960 1961 1962 1963 1964 JavaThread* JavaThread::active() { 1965 Thread* thread = ThreadLocalStorage::thread(); 1966 assert(thread != NULL, "just checking"); 1967 if (thread->is_Java_thread()) { 1968 return (JavaThread*) thread; 1969 } else { 1970 assert(thread->is_VM_thread(), "this must be a vm thread"); 1971 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1972 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1973 assert(ret->is_Java_thread(), "must be a Java thread"); 1974 return ret; 1975 } 1976 } 1977 1978 bool JavaThread::is_lock_owned(address adr) const { 1979 if (Thread::is_lock_owned(adr)) return true; 1980 1981 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1982 if (chunk->contains(adr)) return true; 1983 } 1984 1985 return false; 1986 } 1987 1988 1989 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1990 chunk->set_next(monitor_chunks()); 1991 set_monitor_chunks(chunk); 1992 } 1993 1994 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1995 guarantee(monitor_chunks() != NULL, "must be non empty"); 1996 if (monitor_chunks() == chunk) { 1997 set_monitor_chunks(chunk->next()); 1998 } else { 1999 MonitorChunk* prev = monitor_chunks(); 2000 while (prev->next() != chunk) prev = prev->next(); 2001 prev->set_next(chunk->next()); 2002 } 2003 } 2004 2005 // JVM support. 2006 2007 // Note: this function shouldn't block if it's called in 2008 // _thread_in_native_trans state (such as from 2009 // check_special_condition_for_native_trans()). 2010 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2011 2012 if (has_last_Java_frame() && has_async_condition()) { 2013 // If we are at a polling page safepoint (not a poll return) 2014 // then we must defer async exception because live registers 2015 // will be clobbered by the exception path. Poll return is 2016 // ok because the call we a returning from already collides 2017 // with exception handling registers and so there is no issue. 2018 // (The exception handling path kills call result registers but 2019 // this is ok since the exception kills the result anyway). 2020 2021 if (is_at_poll_safepoint()) { 2022 // if the code we are returning to has deoptimized we must defer 2023 // the exception otherwise live registers get clobbered on the 2024 // exception path before deoptimization is able to retrieve them. 2025 // 2026 RegisterMap map(this, false); 2027 frame caller_fr = last_frame().sender(&map); 2028 assert(caller_fr.is_compiled_frame(), "what?"); 2029 if (caller_fr.is_deoptimized_frame()) { 2030 if (TraceExceptions) { 2031 ResourceMark rm; 2032 tty->print_cr("deferred async exception at compiled safepoint"); 2033 } 2034 return; 2035 } 2036 } 2037 } 2038 2039 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2040 if (condition == _no_async_condition) { 2041 // Conditions have changed since has_special_runtime_exit_condition() 2042 // was called: 2043 // - if we were here only because of an external suspend request, 2044 // then that was taken care of above (or cancelled) so we are done 2045 // - if we were here because of another async request, then it has 2046 // been cleared between the has_special_runtime_exit_condition() 2047 // and now so again we are done 2048 return; 2049 } 2050 2051 // Check for pending async. exception 2052 if (_pending_async_exception != NULL) { 2053 // Only overwrite an already pending exception, if it is not a threadDeath. 2054 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2055 2056 // We cannot call Exceptions::_throw(...) here because we cannot block 2057 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2058 2059 if (TraceExceptions) { 2060 ResourceMark rm; 2061 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2062 if (has_last_Java_frame()) { 2063 frame f = last_frame(); 2064 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2065 } 2066 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2067 } 2068 _pending_async_exception = NULL; 2069 clear_has_async_exception(); 2070 } 2071 } 2072 2073 if (check_unsafe_error && 2074 condition == _async_unsafe_access_error && !has_pending_exception()) { 2075 condition = _no_async_condition; // done 2076 switch (thread_state()) { 2077 case _thread_in_vm: 2078 { 2079 JavaThread* THREAD = this; 2080 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2081 } 2082 case _thread_in_native: 2083 { 2084 ThreadInVMfromNative tiv(this); 2085 JavaThread* THREAD = this; 2086 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2087 } 2088 case _thread_in_Java: 2089 { 2090 ThreadInVMfromJava tiv(this); 2091 JavaThread* THREAD = this; 2092 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2093 } 2094 default: 2095 ShouldNotReachHere(); 2096 } 2097 } 2098 2099 assert(condition == _no_async_condition || has_pending_exception() || 2100 (!check_unsafe_error && condition == _async_unsafe_access_error), 2101 "must have handled the async condition, if no exception"); 2102 } 2103 2104 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2105 // 2106 // Check for pending external suspend. Internal suspend requests do 2107 // not use handle_special_runtime_exit_condition(). 2108 // If JNIEnv proxies are allowed, don't self-suspend if the target 2109 // thread is not the current thread. In older versions of jdbx, jdbx 2110 // threads could call into the VM with another thread's JNIEnv so we 2111 // can be here operating on behalf of a suspended thread (4432884). 2112 bool do_self_suspend = is_external_suspend_with_lock(); 2113 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2114 // 2115 // Because thread is external suspended the safepoint code will count 2116 // thread as at a safepoint. This can be odd because we can be here 2117 // as _thread_in_Java which would normally transition to _thread_blocked 2118 // at a safepoint. We would like to mark the thread as _thread_blocked 2119 // before calling java_suspend_self like all other callers of it but 2120 // we must then observe proper safepoint protocol. (We can't leave 2121 // _thread_blocked with a safepoint in progress). However we can be 2122 // here as _thread_in_native_trans so we can't use a normal transition 2123 // constructor/destructor pair because they assert on that type of 2124 // transition. We could do something like: 2125 // 2126 // JavaThreadState state = thread_state(); 2127 // set_thread_state(_thread_in_vm); 2128 // { 2129 // ThreadBlockInVM tbivm(this); 2130 // java_suspend_self() 2131 // } 2132 // set_thread_state(_thread_in_vm_trans); 2133 // if (safepoint) block; 2134 // set_thread_state(state); 2135 // 2136 // but that is pretty messy. Instead we just go with the way the 2137 // code has worked before and note that this is the only path to 2138 // java_suspend_self that doesn't put the thread in _thread_blocked 2139 // mode. 2140 2141 frame_anchor()->make_walkable(this); 2142 java_suspend_self(); 2143 2144 // We might be here for reasons in addition to the self-suspend request 2145 // so check for other async requests. 2146 } 2147 2148 if (check_asyncs) { 2149 check_and_handle_async_exceptions(); 2150 } 2151 } 2152 2153 void JavaThread::send_thread_stop(oop java_throwable) { 2154 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2155 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2156 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2157 2158 // Do not throw asynchronous exceptions against the compiler thread 2159 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2160 if (is_Compiler_thread()) return; 2161 2162 { 2163 // Actually throw the Throwable against the target Thread - however 2164 // only if there is no thread death exception installed already. 2165 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2166 // If the topmost frame is a runtime stub, then we are calling into 2167 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2168 // must deoptimize the caller before continuing, as the compiled exception handler table 2169 // may not be valid 2170 if (has_last_Java_frame()) { 2171 frame f = last_frame(); 2172 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2173 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2174 RegisterMap reg_map(this, UseBiasedLocking); 2175 frame compiled_frame = f.sender(®_map); 2176 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2177 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2178 } 2179 } 2180 } 2181 2182 // Set async. pending exception in thread. 2183 set_pending_async_exception(java_throwable); 2184 2185 if (TraceExceptions) { 2186 ResourceMark rm; 2187 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2188 } 2189 // for AbortVMOnException flag 2190 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2191 } 2192 } 2193 2194 2195 // Interrupt thread so it will wake up from a potential wait() 2196 Thread::interrupt(this); 2197 } 2198 2199 // External suspension mechanism. 2200 // 2201 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2202 // to any VM_locks and it is at a transition 2203 // Self-suspension will happen on the transition out of the vm. 2204 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2205 // 2206 // Guarantees on return: 2207 // + Target thread will not execute any new bytecode (that's why we need to 2208 // force a safepoint) 2209 // + Target thread will not enter any new monitors 2210 // 2211 void JavaThread::java_suspend() { 2212 { MutexLocker mu(Threads_lock); 2213 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2214 return; 2215 } 2216 } 2217 2218 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2219 if (!is_external_suspend()) { 2220 // a racing resume has cancelled us; bail out now 2221 return; 2222 } 2223 2224 // suspend is done 2225 uint32_t debug_bits = 0; 2226 // Warning: is_ext_suspend_completed() may temporarily drop the 2227 // SR_lock to allow the thread to reach a stable thread state if 2228 // it is currently in a transient thread state. 2229 if (is_ext_suspend_completed(false /* !called_by_wait */, 2230 SuspendRetryDelay, &debug_bits) ) { 2231 return; 2232 } 2233 } 2234 2235 VM_ForceSafepoint vm_suspend; 2236 VMThread::execute(&vm_suspend); 2237 } 2238 2239 // Part II of external suspension. 2240 // A JavaThread self suspends when it detects a pending external suspend 2241 // request. This is usually on transitions. It is also done in places 2242 // where continuing to the next transition would surprise the caller, 2243 // e.g., monitor entry. 2244 // 2245 // Returns the number of times that the thread self-suspended. 2246 // 2247 // Note: DO NOT call java_suspend_self() when you just want to block current 2248 // thread. java_suspend_self() is the second stage of cooperative 2249 // suspension for external suspend requests and should only be used 2250 // to complete an external suspend request. 2251 // 2252 int JavaThread::java_suspend_self() { 2253 int ret = 0; 2254 2255 // we are in the process of exiting so don't suspend 2256 if (is_exiting()) { 2257 clear_external_suspend(); 2258 return ret; 2259 } 2260 2261 assert(_anchor.walkable() || 2262 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2263 "must have walkable stack"); 2264 2265 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2266 2267 assert(!this->is_ext_suspended(), 2268 "a thread trying to self-suspend should not already be suspended"); 2269 2270 if (this->is_suspend_equivalent()) { 2271 // If we are self-suspending as a result of the lifting of a 2272 // suspend equivalent condition, then the suspend_equivalent 2273 // flag is not cleared until we set the ext_suspended flag so 2274 // that wait_for_ext_suspend_completion() returns consistent 2275 // results. 2276 this->clear_suspend_equivalent(); 2277 } 2278 2279 // A racing resume may have cancelled us before we grabbed SR_lock 2280 // above. Or another external suspend request could be waiting for us 2281 // by the time we return from SR_lock()->wait(). The thread 2282 // that requested the suspension may already be trying to walk our 2283 // stack and if we return now, we can change the stack out from under 2284 // it. This would be a "bad thing (TM)" and cause the stack walker 2285 // to crash. We stay self-suspended until there are no more pending 2286 // external suspend requests. 2287 while (is_external_suspend()) { 2288 ret++; 2289 this->set_ext_suspended(); 2290 2291 // _ext_suspended flag is cleared by java_resume() 2292 while (is_ext_suspended()) { 2293 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2294 } 2295 } 2296 2297 return ret; 2298 } 2299 2300 #ifdef ASSERT 2301 // verify the JavaThread has not yet been published in the Threads::list, and 2302 // hence doesn't need protection from concurrent access at this stage 2303 void JavaThread::verify_not_published() { 2304 if (!Threads_lock->owned_by_self()) { 2305 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2306 assert(!Threads::includes(this), 2307 "java thread shouldn't have been published yet!"); 2308 } 2309 else { 2310 assert(!Threads::includes(this), 2311 "java thread shouldn't have been published yet!"); 2312 } 2313 } 2314 #endif 2315 2316 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2317 // progress or when _suspend_flags is non-zero. 2318 // Current thread needs to self-suspend if there is a suspend request and/or 2319 // block if a safepoint is in progress. 2320 // Async exception ISN'T checked. 2321 // Note only the ThreadInVMfromNative transition can call this function 2322 // directly and when thread state is _thread_in_native_trans 2323 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2324 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2325 2326 JavaThread *curJT = JavaThread::current(); 2327 bool do_self_suspend = thread->is_external_suspend(); 2328 2329 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2330 2331 // If JNIEnv proxies are allowed, don't self-suspend if the target 2332 // thread is not the current thread. In older versions of jdbx, jdbx 2333 // threads could call into the VM with another thread's JNIEnv so we 2334 // can be here operating on behalf of a suspended thread (4432884). 2335 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2336 JavaThreadState state = thread->thread_state(); 2337 2338 // We mark this thread_blocked state as a suspend-equivalent so 2339 // that a caller to is_ext_suspend_completed() won't be confused. 2340 // The suspend-equivalent state is cleared by java_suspend_self(). 2341 thread->set_suspend_equivalent(); 2342 2343 // If the safepoint code sees the _thread_in_native_trans state, it will 2344 // wait until the thread changes to other thread state. There is no 2345 // guarantee on how soon we can obtain the SR_lock and complete the 2346 // self-suspend request. It would be a bad idea to let safepoint wait for 2347 // too long. Temporarily change the state to _thread_blocked to 2348 // let the VM thread know that this thread is ready for GC. The problem 2349 // of changing thread state is that safepoint could happen just after 2350 // java_suspend_self() returns after being resumed, and VM thread will 2351 // see the _thread_blocked state. We must check for safepoint 2352 // after restoring the state and make sure we won't leave while a safepoint 2353 // is in progress. 2354 thread->set_thread_state(_thread_blocked); 2355 thread->java_suspend_self(); 2356 thread->set_thread_state(state); 2357 // Make sure new state is seen by VM thread 2358 if (os::is_MP()) { 2359 if (UseMembar) { 2360 // Force a fence between the write above and read below 2361 OrderAccess::fence(); 2362 } else { 2363 // Must use this rather than serialization page in particular on Windows 2364 InterfaceSupport::serialize_memory(thread); 2365 } 2366 } 2367 } 2368 2369 if (SafepointSynchronize::do_call_back()) { 2370 // If we are safepointing, then block the caller which may not be 2371 // the same as the target thread (see above). 2372 SafepointSynchronize::block(curJT); 2373 } 2374 2375 if (thread->is_deopt_suspend()) { 2376 thread->clear_deopt_suspend(); 2377 RegisterMap map(thread, false); 2378 frame f = thread->last_frame(); 2379 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2380 f = f.sender(&map); 2381 } 2382 if (f.id() == thread->must_deopt_id()) { 2383 thread->clear_must_deopt_id(); 2384 f.deoptimize(thread); 2385 } else { 2386 fatal("missed deoptimization!"); 2387 } 2388 } 2389 } 2390 2391 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2392 // progress or when _suspend_flags is non-zero. 2393 // Current thread needs to self-suspend if there is a suspend request and/or 2394 // block if a safepoint is in progress. 2395 // Also check for pending async exception (not including unsafe access error). 2396 // Note only the native==>VM/Java barriers can call this function and when 2397 // thread state is _thread_in_native_trans. 2398 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2399 check_safepoint_and_suspend_for_native_trans(thread); 2400 2401 if (thread->has_async_exception()) { 2402 // We are in _thread_in_native_trans state, don't handle unsafe 2403 // access error since that may block. 2404 thread->check_and_handle_async_exceptions(false); 2405 } 2406 } 2407 2408 // This is a variant of the normal 2409 // check_special_condition_for_native_trans with slightly different 2410 // semantics for use by critical native wrappers. It does all the 2411 // normal checks but also performs the transition back into 2412 // thread_in_Java state. This is required so that critical natives 2413 // can potentially block and perform a GC if they are the last thread 2414 // exiting the GC_locker. 2415 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2416 check_special_condition_for_native_trans(thread); 2417 2418 // Finish the transition 2419 thread->set_thread_state(_thread_in_Java); 2420 2421 if (thread->do_critical_native_unlock()) { 2422 ThreadInVMfromJavaNoAsyncException tiv(thread); 2423 GC_locker::unlock_critical(thread); 2424 thread->clear_critical_native_unlock(); 2425 } 2426 } 2427 2428 // We need to guarantee the Threads_lock here, since resumes are not 2429 // allowed during safepoint synchronization 2430 // Can only resume from an external suspension 2431 void JavaThread::java_resume() { 2432 assert_locked_or_safepoint(Threads_lock); 2433 2434 // Sanity check: thread is gone, has started exiting or the thread 2435 // was not externally suspended. 2436 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2437 return; 2438 } 2439 2440 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2441 2442 clear_external_suspend(); 2443 2444 if (is_ext_suspended()) { 2445 clear_ext_suspended(); 2446 SR_lock()->notify_all(); 2447 } 2448 } 2449 2450 void JavaThread::create_stack_guard_pages() { 2451 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2452 address low_addr = stack_base() - stack_size(); 2453 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2454 2455 int allocate = os::allocate_stack_guard_pages(); 2456 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2457 2458 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2459 warning("Attempt to allocate stack guard pages failed."); 2460 return; 2461 } 2462 2463 if (os::guard_memory((char *) low_addr, len)) { 2464 _stack_guard_state = stack_guard_enabled; 2465 } else { 2466 warning("Attempt to protect stack guard pages failed."); 2467 if (os::uncommit_memory((char *) low_addr, len)) { 2468 warning("Attempt to deallocate stack guard pages failed."); 2469 } 2470 } 2471 } 2472 2473 void JavaThread::remove_stack_guard_pages() { 2474 assert(Thread::current() == this, "from different thread"); 2475 if (_stack_guard_state == stack_guard_unused) return; 2476 address low_addr = stack_base() - stack_size(); 2477 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2478 2479 if (os::allocate_stack_guard_pages()) { 2480 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2481 _stack_guard_state = stack_guard_unused; 2482 } else { 2483 warning("Attempt to deallocate stack guard pages failed."); 2484 } 2485 } else { 2486 if (_stack_guard_state == stack_guard_unused) return; 2487 if (os::unguard_memory((char *) low_addr, len)) { 2488 _stack_guard_state = stack_guard_unused; 2489 } else { 2490 warning("Attempt to unprotect stack guard pages failed."); 2491 } 2492 } 2493 } 2494 2495 void JavaThread::enable_stack_yellow_zone() { 2496 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2497 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2498 2499 // The base notation is from the stacks point of view, growing downward. 2500 // We need to adjust it to work correctly with guard_memory() 2501 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2502 2503 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2504 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2505 2506 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2507 _stack_guard_state = stack_guard_enabled; 2508 } else { 2509 warning("Attempt to guard stack yellow zone failed."); 2510 } 2511 enable_register_stack_guard(); 2512 } 2513 2514 void JavaThread::disable_stack_yellow_zone() { 2515 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2516 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2517 2518 // Simply return if called for a thread that does not use guard pages. 2519 if (_stack_guard_state == stack_guard_unused) return; 2520 2521 // The base notation is from the stacks point of view, growing downward. 2522 // We need to adjust it to work correctly with guard_memory() 2523 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2524 2525 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2526 _stack_guard_state = stack_guard_yellow_disabled; 2527 } else { 2528 warning("Attempt to unguard stack yellow zone failed."); 2529 } 2530 disable_register_stack_guard(); 2531 } 2532 2533 void JavaThread::enable_stack_red_zone() { 2534 // The base notation is from the stacks point of view, growing downward. 2535 // We need to adjust it to work correctly with guard_memory() 2536 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2537 address base = stack_red_zone_base() - stack_red_zone_size(); 2538 2539 guarantee(base < stack_base(), "Error calculating stack red zone"); 2540 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2541 2542 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2543 warning("Attempt to guard stack red zone failed."); 2544 } 2545 } 2546 2547 void JavaThread::disable_stack_red_zone() { 2548 // The base notation is from the stacks point of view, growing downward. 2549 // We need to adjust it to work correctly with guard_memory() 2550 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2551 address base = stack_red_zone_base() - stack_red_zone_size(); 2552 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2553 warning("Attempt to unguard stack red zone failed."); 2554 } 2555 } 2556 2557 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2558 // ignore is there is no stack 2559 if (!has_last_Java_frame()) return; 2560 // traverse the stack frames. Starts from top frame. 2561 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2562 frame* fr = fst.current(); 2563 f(fr, fst.register_map()); 2564 } 2565 } 2566 2567 2568 #ifndef PRODUCT 2569 // Deoptimization 2570 // Function for testing deoptimization 2571 void JavaThread::deoptimize() { 2572 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2573 StackFrameStream fst(this, UseBiasedLocking); 2574 bool deopt = false; // Dump stack only if a deopt actually happens. 2575 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2576 // Iterate over all frames in the thread and deoptimize 2577 for (; !fst.is_done(); fst.next()) { 2578 if (fst.current()->can_be_deoptimized()) { 2579 2580 if (only_at) { 2581 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2582 // consists of comma or carriage return separated numbers so 2583 // search for the current bci in that string. 2584 address pc = fst.current()->pc(); 2585 nmethod* nm = (nmethod*) fst.current()->cb(); 2586 ScopeDesc* sd = nm->scope_desc_at( pc); 2587 char buffer[8]; 2588 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2589 size_t len = strlen(buffer); 2590 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2591 while (found != NULL) { 2592 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2593 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2594 // Check that the bci found is bracketed by terminators. 2595 break; 2596 } 2597 found = strstr(found + 1, buffer); 2598 } 2599 if (!found) { 2600 continue; 2601 } 2602 } 2603 2604 if (DebugDeoptimization && !deopt) { 2605 deopt = true; // One-time only print before deopt 2606 tty->print_cr("[BEFORE Deoptimization]"); 2607 trace_frames(); 2608 trace_stack(); 2609 } 2610 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2611 } 2612 } 2613 2614 if (DebugDeoptimization && deopt) { 2615 tty->print_cr("[AFTER Deoptimization]"); 2616 trace_frames(); 2617 } 2618 } 2619 2620 2621 // Make zombies 2622 void JavaThread::make_zombies() { 2623 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2624 if (fst.current()->can_be_deoptimized()) { 2625 // it is a Java nmethod 2626 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2627 nm->make_not_entrant(); 2628 } 2629 } 2630 } 2631 #endif // PRODUCT 2632 2633 2634 void JavaThread::deoptimized_wrt_marked_nmethods() { 2635 if (!has_last_Java_frame()) return; 2636 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2637 StackFrameStream fst(this, UseBiasedLocking); 2638 for (; !fst.is_done(); fst.next()) { 2639 if (fst.current()->should_be_deoptimized()) { 2640 if (LogCompilation && xtty != NULL) { 2641 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2642 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2643 this->name(), nm != NULL ? nm->compile_id() : -1); 2644 } 2645 2646 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2647 } 2648 } 2649 } 2650 2651 2652 // GC support 2653 static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2654 2655 void JavaThread::gc_epilogue() { 2656 frames_do(frame_gc_epilogue); 2657 } 2658 2659 2660 static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2661 2662 void JavaThread::gc_prologue() { 2663 frames_do(frame_gc_prologue); 2664 } 2665 2666 // If the caller is a NamedThread, then remember, in the current scope, 2667 // the given JavaThread in its _processed_thread field. 2668 class RememberProcessedThread: public StackObj { 2669 NamedThread* _cur_thr; 2670 public: 2671 RememberProcessedThread(JavaThread* jthr) { 2672 Thread* thread = Thread::current(); 2673 if (thread->is_Named_thread()) { 2674 _cur_thr = (NamedThread *)thread; 2675 _cur_thr->set_processed_thread(jthr); 2676 } else { 2677 _cur_thr = NULL; 2678 } 2679 } 2680 2681 ~RememberProcessedThread() { 2682 if (_cur_thr) { 2683 _cur_thr->set_processed_thread(NULL); 2684 } 2685 } 2686 }; 2687 2688 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2689 // Verify that the deferred card marks have been flushed. 2690 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2691 2692 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2693 // since there may be more than one thread using each ThreadProfiler. 2694 2695 // Traverse the GCHandles 2696 Thread::oops_do(f, cld_f, cf); 2697 2698 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2699 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2700 2701 if (has_last_Java_frame()) { 2702 // Record JavaThread to GC thread 2703 RememberProcessedThread rpt(this); 2704 2705 // Traverse the privileged stack 2706 if (_privileged_stack_top != NULL) { 2707 _privileged_stack_top->oops_do(f); 2708 } 2709 2710 // traverse the registered growable array 2711 if (_array_for_gc != NULL) { 2712 for (int index = 0; index < _array_for_gc->length(); index++) { 2713 f->do_oop(_array_for_gc->adr_at(index)); 2714 } 2715 } 2716 2717 // Traverse the monitor chunks 2718 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2719 chunk->oops_do(f); 2720 } 2721 2722 // Traverse the execution stack 2723 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2724 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2725 } 2726 } 2727 2728 // callee_target is never live across a gc point so NULL it here should 2729 // it still contain a methdOop. 2730 2731 set_callee_target(NULL); 2732 2733 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2734 // If we have deferred set_locals there might be oops waiting to be 2735 // written 2736 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2737 if (list != NULL) { 2738 for (int i = 0; i < list->length(); i++) { 2739 list->at(i)->oops_do(f); 2740 } 2741 } 2742 2743 // Traverse instance variables at the end since the GC may be moving things 2744 // around using this function 2745 f->do_oop((oop*) &_threadObj); 2746 f->do_oop((oop*) &_vm_result); 2747 f->do_oop((oop*) &_exception_oop); 2748 f->do_oop((oop*) &_pending_async_exception); 2749 2750 if (jvmti_thread_state() != NULL) { 2751 jvmti_thread_state()->oops_do(f); 2752 } 2753 } 2754 2755 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2756 Thread::nmethods_do(cf); // (super method is a no-op) 2757 2758 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2759 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2760 2761 if (has_last_Java_frame()) { 2762 // Traverse the execution stack 2763 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2764 fst.current()->nmethods_do(cf); 2765 } 2766 } 2767 } 2768 2769 void JavaThread::metadata_do(void f(Metadata*)) { 2770 Thread::metadata_do(f); 2771 if (has_last_Java_frame()) { 2772 // Traverse the execution stack to call f() on the methods in the stack 2773 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2774 fst.current()->metadata_do(f); 2775 } 2776 } else if (is_Compiler_thread()) { 2777 // need to walk ciMetadata in current compile tasks to keep alive. 2778 CompilerThread* ct = (CompilerThread*)this; 2779 if (ct->env() != NULL) { 2780 ct->env()->metadata_do(f); 2781 } 2782 } 2783 } 2784 2785 // Printing 2786 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2787 switch (_thread_state) { 2788 case _thread_uninitialized: return "_thread_uninitialized"; 2789 case _thread_new: return "_thread_new"; 2790 case _thread_new_trans: return "_thread_new_trans"; 2791 case _thread_in_native: return "_thread_in_native"; 2792 case _thread_in_native_trans: return "_thread_in_native_trans"; 2793 case _thread_in_vm: return "_thread_in_vm"; 2794 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2795 case _thread_in_Java: return "_thread_in_Java"; 2796 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2797 case _thread_blocked: return "_thread_blocked"; 2798 case _thread_blocked_trans: return "_thread_blocked_trans"; 2799 default: return "unknown thread state"; 2800 } 2801 } 2802 2803 #ifndef PRODUCT 2804 void JavaThread::print_thread_state_on(outputStream *st) const { 2805 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2806 }; 2807 void JavaThread::print_thread_state() const { 2808 print_thread_state_on(tty); 2809 }; 2810 #endif // PRODUCT 2811 2812 // Called by Threads::print() for VM_PrintThreads operation 2813 void JavaThread::print_on(outputStream *st) const { 2814 st->print("\"%s\" ", get_thread_name()); 2815 oop thread_oop = threadObj(); 2816 if (thread_oop != NULL) { 2817 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2818 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2819 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2820 } 2821 Thread::print_on(st); 2822 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2823 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2824 if (thread_oop != NULL) { 2825 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2826 } 2827 #ifndef PRODUCT 2828 print_thread_state_on(st); 2829 _safepoint_state->print_on(st); 2830 #endif // PRODUCT 2831 } 2832 2833 // Called by fatal error handler. The difference between this and 2834 // JavaThread::print() is that we can't grab lock or allocate memory. 2835 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2836 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2837 oop thread_obj = threadObj(); 2838 if (thread_obj != NULL) { 2839 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2840 } 2841 st->print(" ["); 2842 st->print("%s", _get_thread_state_name(_thread_state)); 2843 if (osthread()) { 2844 st->print(", id=%d", osthread()->thread_id()); 2845 } 2846 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2847 _stack_base - _stack_size, _stack_base); 2848 st->print("]"); 2849 return; 2850 } 2851 2852 // Verification 2853 2854 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2855 2856 void JavaThread::verify() { 2857 // Verify oops in the thread. 2858 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2859 2860 // Verify the stack frames. 2861 frames_do(frame_verify); 2862 } 2863 2864 // CR 6300358 (sub-CR 2137150) 2865 // Most callers of this method assume that it can't return NULL but a 2866 // thread may not have a name whilst it is in the process of attaching to 2867 // the VM - see CR 6412693, and there are places where a JavaThread can be 2868 // seen prior to having it's threadObj set (eg JNI attaching threads and 2869 // if vm exit occurs during initialization). These cases can all be accounted 2870 // for such that this method never returns NULL. 2871 const char* JavaThread::get_thread_name() const { 2872 #ifdef ASSERT 2873 // early safepoints can hit while current thread does not yet have TLS 2874 if (!SafepointSynchronize::is_at_safepoint()) { 2875 Thread *cur = Thread::current(); 2876 if (!(cur->is_Java_thread() && cur == this)) { 2877 // Current JavaThreads are allowed to get their own name without 2878 // the Threads_lock. 2879 assert_locked_or_safepoint(Threads_lock); 2880 } 2881 } 2882 #endif // ASSERT 2883 return get_thread_name_string(); 2884 } 2885 2886 // Returns a non-NULL representation of this thread's name, or a suitable 2887 // descriptive string if there is no set name 2888 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2889 const char* name_str; 2890 oop thread_obj = threadObj(); 2891 if (thread_obj != NULL) { 2892 typeArrayOop name = java_lang_Thread::name(thread_obj); 2893 if (name != NULL) { 2894 if (buf == NULL) { 2895 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2896 } 2897 else { 2898 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2899 } 2900 } 2901 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2902 name_str = "<no-name - thread is attaching>"; 2903 } 2904 else { 2905 name_str = Thread::name(); 2906 } 2907 } 2908 else { 2909 name_str = Thread::name(); 2910 } 2911 assert(name_str != NULL, "unexpected NULL thread name"); 2912 return name_str; 2913 } 2914 2915 2916 const char* JavaThread::get_threadgroup_name() const { 2917 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2918 oop thread_obj = threadObj(); 2919 if (thread_obj != NULL) { 2920 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2921 if (thread_group != NULL) { 2922 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2923 // ThreadGroup.name can be null 2924 if (name != NULL) { 2925 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2926 return str; 2927 } 2928 } 2929 } 2930 return NULL; 2931 } 2932 2933 const char* JavaThread::get_parent_name() const { 2934 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2935 oop thread_obj = threadObj(); 2936 if (thread_obj != NULL) { 2937 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2938 if (thread_group != NULL) { 2939 oop parent = java_lang_ThreadGroup::parent(thread_group); 2940 if (parent != NULL) { 2941 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2942 // ThreadGroup.name can be null 2943 if (name != NULL) { 2944 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2945 return str; 2946 } 2947 } 2948 } 2949 } 2950 return NULL; 2951 } 2952 2953 ThreadPriority JavaThread::java_priority() const { 2954 oop thr_oop = threadObj(); 2955 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2956 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2957 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2958 return priority; 2959 } 2960 2961 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2962 2963 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2964 // Link Java Thread object <-> C++ Thread 2965 2966 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2967 // and put it into a new Handle. The Handle "thread_oop" can then 2968 // be used to pass the C++ thread object to other methods. 2969 2970 // Set the Java level thread object (jthread) field of the 2971 // new thread (a JavaThread *) to C++ thread object using the 2972 // "thread_oop" handle. 2973 2974 // Set the thread field (a JavaThread *) of the 2975 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2976 2977 Handle thread_oop(Thread::current(), 2978 JNIHandles::resolve_non_null(jni_thread)); 2979 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 2980 "must be initialized"); 2981 set_threadObj(thread_oop()); 2982 java_lang_Thread::set_thread(thread_oop(), this); 2983 2984 if (prio == NoPriority) { 2985 prio = java_lang_Thread::priority(thread_oop()); 2986 assert(prio != NoPriority, "A valid priority should be present"); 2987 } 2988 2989 // Push the Java priority down to the native thread; needs Threads_lock 2990 Thread::set_priority(this, prio); 2991 2992 // Add the new thread to the Threads list and set it in motion. 2993 // We must have threads lock in order to call Threads::add. 2994 // It is crucial that we do not block before the thread is 2995 // added to the Threads list for if a GC happens, then the java_thread oop 2996 // will not be visited by GC. 2997 Threads::add(this); 2998 } 2999 3000 oop JavaThread::current_park_blocker() { 3001 // Support for JSR-166 locks 3002 oop thread_oop = threadObj(); 3003 if (thread_oop != NULL && 3004 JDK_Version::current().supports_thread_park_blocker()) { 3005 return java_lang_Thread::park_blocker(thread_oop); 3006 } 3007 return NULL; 3008 } 3009 3010 3011 void JavaThread::print_stack_on(outputStream* st) { 3012 if (!has_last_Java_frame()) return; 3013 ResourceMark rm; 3014 HandleMark hm; 3015 3016 RegisterMap reg_map(this); 3017 vframe* start_vf = last_java_vframe(®_map); 3018 int count = 0; 3019 for (vframe* f = start_vf; f; f = f->sender()) { 3020 if (f->is_java_frame()) { 3021 javaVFrame* jvf = javaVFrame::cast(f); 3022 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3023 3024 // Print out lock information 3025 if (JavaMonitorsInStackTrace) { 3026 jvf->print_lock_info_on(st, count); 3027 } 3028 } else { 3029 // Ignore non-Java frames 3030 } 3031 3032 // Bail-out case for too deep stacks 3033 count++; 3034 if (MaxJavaStackTraceDepth == count) return; 3035 } 3036 } 3037 3038 3039 // JVMTI PopFrame support 3040 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3041 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3042 if (in_bytes(size_in_bytes) != 0) { 3043 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3044 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3045 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3046 } 3047 } 3048 3049 void* JavaThread::popframe_preserved_args() { 3050 return _popframe_preserved_args; 3051 } 3052 3053 ByteSize JavaThread::popframe_preserved_args_size() { 3054 return in_ByteSize(_popframe_preserved_args_size); 3055 } 3056 3057 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3058 int sz = in_bytes(popframe_preserved_args_size()); 3059 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3060 return in_WordSize(sz / wordSize); 3061 } 3062 3063 void JavaThread::popframe_free_preserved_args() { 3064 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3065 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3066 _popframe_preserved_args = NULL; 3067 _popframe_preserved_args_size = 0; 3068 } 3069 3070 #ifndef PRODUCT 3071 3072 void JavaThread::trace_frames() { 3073 tty->print_cr("[Describe stack]"); 3074 int frame_no = 1; 3075 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3076 tty->print(" %d. ", frame_no++); 3077 fst.current()->print_value_on(tty, this); 3078 tty->cr(); 3079 } 3080 } 3081 3082 class PrintAndVerifyOopClosure: public OopClosure { 3083 protected: 3084 template <class T> inline void do_oop_work(T* p) { 3085 oop obj = oopDesc::load_decode_heap_oop(p); 3086 if (obj == NULL) return; 3087 tty->print(INTPTR_FORMAT ": ", p); 3088 if (obj->is_oop_or_null()) { 3089 if (obj->is_objArray()) { 3090 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3091 } else { 3092 obj->print(); 3093 } 3094 } else { 3095 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3096 } 3097 tty->cr(); 3098 } 3099 public: 3100 virtual void do_oop(oop* p) { do_oop_work(p); } 3101 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3102 }; 3103 3104 3105 static void oops_print(frame* f, const RegisterMap *map) { 3106 PrintAndVerifyOopClosure print; 3107 f->print_value(); 3108 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3109 } 3110 3111 // Print our all the locations that contain oops and whether they are 3112 // valid or not. This useful when trying to find the oldest frame 3113 // where an oop has gone bad since the frame walk is from youngest to 3114 // oldest. 3115 void JavaThread::trace_oops() { 3116 tty->print_cr("[Trace oops]"); 3117 frames_do(oops_print); 3118 } 3119 3120 3121 #ifdef ASSERT 3122 // Print or validate the layout of stack frames 3123 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3124 ResourceMark rm; 3125 PRESERVE_EXCEPTION_MARK; 3126 FrameValues values; 3127 int frame_no = 0; 3128 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3129 fst.current()->describe(values, ++frame_no); 3130 if (depth == frame_no) break; 3131 } 3132 if (validate_only) { 3133 values.validate(); 3134 } else { 3135 tty->print_cr("[Describe stack layout]"); 3136 values.print(this); 3137 } 3138 } 3139 #endif 3140 3141 void JavaThread::trace_stack_from(vframe* start_vf) { 3142 ResourceMark rm; 3143 int vframe_no = 1; 3144 for (vframe* f = start_vf; f; f = f->sender()) { 3145 if (f->is_java_frame()) { 3146 javaVFrame::cast(f)->print_activation(vframe_no++); 3147 } else { 3148 f->print(); 3149 } 3150 if (vframe_no > StackPrintLimit) { 3151 tty->print_cr("...<more frames>..."); 3152 return; 3153 } 3154 } 3155 } 3156 3157 3158 void JavaThread::trace_stack() { 3159 if (!has_last_Java_frame()) return; 3160 ResourceMark rm; 3161 HandleMark hm; 3162 RegisterMap reg_map(this); 3163 trace_stack_from(last_java_vframe(®_map)); 3164 } 3165 3166 3167 #endif // PRODUCT 3168 3169 3170 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3171 assert(reg_map != NULL, "a map must be given"); 3172 frame f = last_frame(); 3173 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3174 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3175 } 3176 return NULL; 3177 } 3178 3179 3180 Klass* JavaThread::security_get_caller_class(int depth) { 3181 vframeStream vfst(this); 3182 vfst.security_get_caller_frame(depth); 3183 if (!vfst.at_end()) { 3184 return vfst.method()->method_holder(); 3185 } 3186 return NULL; 3187 } 3188 3189 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3190 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3191 CompileBroker::compiler_thread_loop(); 3192 } 3193 3194 // Create a CompilerThread 3195 CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3196 : JavaThread(&compiler_thread_entry) { 3197 _env = NULL; 3198 _log = NULL; 3199 _task = NULL; 3200 _queue = queue; 3201 _counters = counters; 3202 _buffer_blob = NULL; 3203 _scanned_nmethod = NULL; 3204 _compiler = NULL; 3205 3206 #ifndef PRODUCT 3207 _ideal_graph_printer = NULL; 3208 #endif 3209 } 3210 3211 void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3212 JavaThread::oops_do(f, cld_f, cf); 3213 if (_scanned_nmethod != NULL && cf != NULL) { 3214 // Safepoints can occur when the sweeper is scanning an nmethod so 3215 // process it here to make sure it isn't unloaded in the middle of 3216 // a scan. 3217 cf->do_code_blob(_scanned_nmethod); 3218 } 3219 } 3220 3221 3222 // ======= Threads ======== 3223 3224 // The Threads class links together all active threads, and provides 3225 // operations over all threads. It is protected by its own Mutex 3226 // lock, which is also used in other contexts to protect thread 3227 // operations from having the thread being operated on from exiting 3228 // and going away unexpectedly (e.g., safepoint synchronization) 3229 3230 JavaThread* Threads::_thread_list = NULL; 3231 int Threads::_number_of_threads = 0; 3232 int Threads::_number_of_non_daemon_threads = 0; 3233 int Threads::_return_code = 0; 3234 size_t JavaThread::_stack_size_at_create = 0; 3235 #ifdef ASSERT 3236 bool Threads::_vm_complete = false; 3237 #endif 3238 3239 // All JavaThreads 3240 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3241 3242 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3243 void Threads::threads_do(ThreadClosure* tc) { 3244 assert_locked_or_safepoint(Threads_lock); 3245 // ALL_JAVA_THREADS iterates through all JavaThreads 3246 ALL_JAVA_THREADS(p) { 3247 tc->do_thread(p); 3248 } 3249 // Someday we could have a table or list of all non-JavaThreads. 3250 // For now, just manually iterate through them. 3251 tc->do_thread(VMThread::vm_thread()); 3252 Universe::heap()->gc_threads_do(tc); 3253 WatcherThread *wt = WatcherThread::watcher_thread(); 3254 // Strictly speaking, the following NULL check isn't sufficient to make sure 3255 // the data for WatcherThread is still valid upon being examined. However, 3256 // considering that WatchThread terminates when the VM is on the way to 3257 // exit at safepoint, the chance of the above is extremely small. The right 3258 // way to prevent termination of WatcherThread would be to acquire 3259 // Terminator_lock, but we can't do that without violating the lock rank 3260 // checking in some cases. 3261 if (wt != NULL) 3262 tc->do_thread(wt); 3263 3264 // If CompilerThreads ever become non-JavaThreads, add them here 3265 } 3266 3267 3268 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3269 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3270 3271 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3272 create_vm_init_libraries(); 3273 } 3274 3275 initialize_class(vmSymbols::java_lang_String(), CHECK); 3276 3277 // Initialize java_lang.System (needed before creating the thread) 3278 initialize_class(vmSymbols::java_lang_System(), CHECK); 3279 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3280 Handle thread_group = create_initial_thread_group(CHECK); 3281 Universe::set_main_thread_group(thread_group()); 3282 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3283 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3284 main_thread->set_threadObj(thread_object); 3285 // Set thread status to running since main thread has 3286 // been started and running. 3287 java_lang_Thread::set_thread_status(thread_object, 3288 java_lang_Thread::RUNNABLE); 3289 3290 // The VM creates & returns objects of this class. Make sure it's initialized. 3291 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3292 3293 // The VM preresolves methods to these classes. Make sure that they get initialized 3294 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3295 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3296 call_initializeSystemClass(CHECK); 3297 3298 // get the Java runtime name after java.lang.System is initialized 3299 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3300 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3301 3302 // an instance of OutOfMemory exception has been allocated earlier 3303 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3304 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3305 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3306 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3307 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3308 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3309 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3310 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3311 } 3312 3313 void Threads::initialize_jsr292_core_classes(TRAPS) { 3314 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3315 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3316 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3317 } 3318 3319 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3320 3321 extern void JDK_Version_init(); 3322 3323 // Check version 3324 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3325 3326 // Initialize the output stream module 3327 ostream_init(); 3328 3329 // Process java launcher properties. 3330 Arguments::process_sun_java_launcher_properties(args); 3331 3332 // Initialize the os module before using TLS 3333 os::init(); 3334 3335 // Initialize system properties. 3336 Arguments::init_system_properties(); 3337 3338 // So that JDK version can be used as a discriminator when parsing arguments 3339 JDK_Version_init(); 3340 3341 // Update/Initialize System properties after JDK version number is known 3342 Arguments::init_version_specific_system_properties(); 3343 3344 // Parse arguments 3345 jint parse_result = Arguments::parse(args); 3346 if (parse_result != JNI_OK) return parse_result; 3347 3348 os::init_before_ergo(); 3349 3350 jint ergo_result = Arguments::apply_ergo(); 3351 if (ergo_result != JNI_OK) return ergo_result; 3352 3353 if (PauseAtStartup) { 3354 os::pause(); 3355 } 3356 3357 HOTSPOT_VM_INIT_BEGIN(); 3358 3359 // Record VM creation timing statistics 3360 TraceVmCreationTime create_vm_timer; 3361 create_vm_timer.start(); 3362 3363 // Timing (must come after argument parsing) 3364 TraceTime timer("Create VM", TraceStartupTime); 3365 3366 // Initialize the os module after parsing the args 3367 jint os_init_2_result = os::init_2(); 3368 if (os_init_2_result != JNI_OK) return os_init_2_result; 3369 3370 jint adjust_after_os_result = Arguments::adjust_after_os(); 3371 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3372 3373 // initialize TLS 3374 ThreadLocalStorage::init(); 3375 3376 // Bootstrap native memory tracking, so it can start recording memory 3377 // activities before worker thread is started. This is the first phase 3378 // of bootstrapping, VM is currently running in single-thread mode. 3379 MemTracker::bootstrap_single_thread(); 3380 3381 // Initialize output stream logging 3382 ostream_init_log(); 3383 3384 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3385 // Must be before create_vm_init_agents() 3386 if (Arguments::init_libraries_at_startup()) { 3387 convert_vm_init_libraries_to_agents(); 3388 } 3389 3390 // Launch -agentlib/-agentpath and converted -Xrun agents 3391 if (Arguments::init_agents_at_startup()) { 3392 create_vm_init_agents(); 3393 } 3394 3395 // Initialize Threads state 3396 _thread_list = NULL; 3397 _number_of_threads = 0; 3398 _number_of_non_daemon_threads = 0; 3399 3400 // Initialize global data structures and create system classes in heap 3401 vm_init_globals(); 3402 3403 // Attach the main thread to this os thread 3404 JavaThread* main_thread = new JavaThread(); 3405 main_thread->set_thread_state(_thread_in_vm); 3406 // must do this before set_active_handles and initialize_thread_local_storage 3407 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3408 // change the stack size recorded here to one based on the java thread 3409 // stacksize. This adjusted size is what is used to figure the placement 3410 // of the guard pages. 3411 main_thread->record_stack_base_and_size(); 3412 main_thread->initialize_thread_local_storage(); 3413 3414 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3415 3416 if (!main_thread->set_as_starting_thread()) { 3417 vm_shutdown_during_initialization( 3418 "Failed necessary internal allocation. Out of swap space"); 3419 delete main_thread; 3420 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3421 return JNI_ENOMEM; 3422 } 3423 3424 // Enable guard page *after* os::create_main_thread(), otherwise it would 3425 // crash Linux VM, see notes in os_linux.cpp. 3426 main_thread->create_stack_guard_pages(); 3427 3428 // Initialize Java-Level synchronization subsystem 3429 ObjectMonitor::Initialize(); 3430 3431 // Second phase of bootstrapping, VM is about entering multi-thread mode 3432 MemTracker::bootstrap_multi_thread(); 3433 3434 // Initialize global modules 3435 jint status = init_globals(); 3436 if (status != JNI_OK) { 3437 delete main_thread; 3438 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3439 return status; 3440 } 3441 3442 // Should be done after the heap is fully created 3443 main_thread->cache_global_variables(); 3444 3445 HandleMark hm; 3446 3447 { MutexLocker mu(Threads_lock); 3448 Threads::add(main_thread); 3449 } 3450 3451 // Any JVMTI raw monitors entered in onload will transition into 3452 // real raw monitor. VM is setup enough here for raw monitor enter. 3453 JvmtiExport::transition_pending_onload_raw_monitors(); 3454 3455 // Fully start NMT 3456 MemTracker::start(); 3457 3458 // Create the VMThread 3459 { TraceTime timer("Start VMThread", TraceStartupTime); 3460 VMThread::create(); 3461 Thread* vmthread = VMThread::vm_thread(); 3462 3463 if (!os::create_thread(vmthread, os::vm_thread)) 3464 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3465 3466 // Wait for the VM thread to become ready, and VMThread::run to initialize 3467 // Monitors can have spurious returns, must always check another state flag 3468 { 3469 MutexLocker ml(Notify_lock); 3470 os::start_thread(vmthread); 3471 while (vmthread->active_handles() == NULL) { 3472 Notify_lock->wait(); 3473 } 3474 } 3475 } 3476 3477 assert(Universe::is_fully_initialized(), "not initialized"); 3478 if (VerifyDuringStartup) { 3479 // Make sure we're starting with a clean slate. 3480 VM_Verify verify_op; 3481 VMThread::execute(&verify_op); 3482 } 3483 3484 Thread* THREAD = Thread::current(); 3485 3486 // At this point, the Universe is initialized, but we have not executed 3487 // any byte code. Now is a good time (the only time) to dump out the 3488 // internal state of the JVM for sharing. 3489 if (DumpSharedSpaces) { 3490 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3491 ShouldNotReachHere(); 3492 } 3493 3494 // Always call even when there are not JVMTI environments yet, since environments 3495 // may be attached late and JVMTI must track phases of VM execution 3496 JvmtiExport::enter_start_phase(); 3497 3498 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3499 JvmtiExport::post_vm_start(); 3500 3501 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3502 3503 // We need this for ClassDataSharing - the initial vm.info property is set 3504 // with the default value of CDS "sharing" which may be reset through 3505 // command line options. 3506 reset_vm_info_property(CHECK_JNI_ERR); 3507 3508 quicken_jni_functions(); 3509 3510 // Must be run after init_ft which initializes ft_enabled 3511 if (TRACE_INITIALIZE() != JNI_OK) { 3512 vm_exit_during_initialization("Failed to initialize tracing backend"); 3513 } 3514 3515 // Set flag that basic initialization has completed. Used by exceptions and various 3516 // debug stuff, that does not work until all basic classes have been initialized. 3517 set_init_completed(); 3518 3519 Metaspace::post_initialize(); 3520 3521 HOTSPOT_VM_INIT_END(); 3522 3523 // record VM initialization completion time 3524 #if INCLUDE_MANAGEMENT 3525 Management::record_vm_init_completed(); 3526 #endif // INCLUDE_MANAGEMENT 3527 3528 // Compute system loader. Note that this has to occur after set_init_completed, since 3529 // valid exceptions may be thrown in the process. 3530 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3531 // set_init_completed has just been called, causing exceptions not to be shortcut 3532 // anymore. We call vm_exit_during_initialization directly instead. 3533 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR); 3534 3535 #if INCLUDE_ALL_GCS 3536 // Support for ConcurrentMarkSweep. This should be cleaned up 3537 // and better encapsulated. The ugly nested if test would go away 3538 // once things are properly refactored. XXX YSR 3539 if (UseConcMarkSweepGC || UseG1GC) { 3540 if (UseConcMarkSweepGC) { 3541 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3542 } else { 3543 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3544 } 3545 } 3546 #endif // INCLUDE_ALL_GCS 3547 3548 // Always call even when there are not JVMTI environments yet, since environments 3549 // may be attached late and JVMTI must track phases of VM execution 3550 JvmtiExport::enter_live_phase(); 3551 3552 // Signal Dispatcher needs to be started before VMInit event is posted 3553 os::signal_init(); 3554 3555 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3556 if (!DisableAttachMechanism) { 3557 AttachListener::vm_start(); 3558 if (StartAttachListener || AttachListener::init_at_startup()) { 3559 AttachListener::init(); 3560 } 3561 } 3562 3563 // Launch -Xrun agents 3564 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3565 // back-end can launch with -Xdebug -Xrunjdwp. 3566 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3567 create_vm_init_libraries(); 3568 } 3569 3570 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3571 JvmtiExport::post_vm_initialized(); 3572 3573 if (TRACE_START() != JNI_OK) { 3574 vm_exit_during_initialization("Failed to start tracing backend."); 3575 } 3576 3577 if (CleanChunkPoolAsync) { 3578 Chunk::start_chunk_pool_cleaner_task(); 3579 } 3580 3581 // initialize compiler(s) 3582 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3583 CompileBroker::compilation_init(); 3584 #endif 3585 3586 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3587 // It is done after compilers are initialized, because otherwise compilations of 3588 // signature polymorphic MH intrinsics can be missed 3589 // (see SystemDictionary::find_method_handle_intrinsic). 3590 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3591 3592 #if INCLUDE_MANAGEMENT 3593 Management::initialize(THREAD); 3594 3595 if (HAS_PENDING_EXCEPTION) { 3596 // management agent fails to start possibly due to 3597 // configuration problem and is responsible for printing 3598 // stack trace if appropriate. Simply exit VM. 3599 vm_exit(1); 3600 } 3601 #endif // INCLUDE_MANAGEMENT 3602 3603 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3604 if (MemProfiling) MemProfiler::engage(); 3605 StatSampler::engage(); 3606 if (CheckJNICalls) JniPeriodicChecker::engage(); 3607 3608 BiasedLocking::init(); 3609 3610 #if INCLUDE_RTM_OPT 3611 RTMLockingCounters::init(); 3612 #endif 3613 3614 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3615 call_postVMInitHook(THREAD); 3616 // The Java side of PostVMInitHook.run must deal with all 3617 // exceptions and provide means of diagnosis. 3618 if (HAS_PENDING_EXCEPTION) { 3619 CLEAR_PENDING_EXCEPTION; 3620 } 3621 } 3622 3623 { 3624 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3625 // Make sure the watcher thread can be started by WatcherThread::start() 3626 // or by dynamic enrollment. 3627 WatcherThread::make_startable(); 3628 // Start up the WatcherThread if there are any periodic tasks 3629 // NOTE: All PeriodicTasks should be registered by now. If they 3630 // aren't, late joiners might appear to start slowly (we might 3631 // take a while to process their first tick). 3632 if (PeriodicTask::num_tasks() > 0) { 3633 WatcherThread::start(); 3634 } 3635 } 3636 3637 // Give os specific code one last chance to start 3638 os::init_3(); 3639 3640 create_vm_timer.end(); 3641 #ifdef ASSERT 3642 _vm_complete = true; 3643 #endif 3644 return JNI_OK; 3645 } 3646 3647 // type for the Agent_OnLoad and JVM_OnLoad entry points 3648 extern "C" { 3649 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3650 } 3651 // Find a command line agent library and return its entry point for 3652 // -agentlib: -agentpath: -Xrun 3653 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3654 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3655 OnLoadEntry_t on_load_entry = NULL; 3656 void *library = NULL; 3657 3658 if (!agent->valid()) { 3659 char buffer[JVM_MAXPATHLEN]; 3660 char ebuf[1024]; 3661 const char *name = agent->name(); 3662 const char *msg = "Could not find agent library "; 3663 3664 // First check to see if agent is statically linked into executable 3665 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3666 library = agent->os_lib(); 3667 } else if (agent->is_absolute_path()) { 3668 library = os::dll_load(name, ebuf, sizeof ebuf); 3669 if (library == NULL) { 3670 const char *sub_msg = " in absolute path, with error: "; 3671 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3672 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3673 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3674 // If we can't find the agent, exit. 3675 vm_exit_during_initialization(buf, NULL); 3676 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3677 } 3678 } else { 3679 // Try to load the agent from the standard dll directory 3680 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3681 name)) { 3682 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3683 } 3684 if (library == NULL) { // Try the local directory 3685 char ns[1] = {0}; 3686 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3687 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3688 } 3689 if (library == NULL) { 3690 const char *sub_msg = " on the library path, with error: "; 3691 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3692 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3693 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3694 // If we can't find the agent, exit. 3695 vm_exit_during_initialization(buf, NULL); 3696 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3697 } 3698 } 3699 } 3700 agent->set_os_lib(library); 3701 agent->set_valid(); 3702 } 3703 3704 // Find the OnLoad function. 3705 on_load_entry = 3706 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3707 false, 3708 on_load_symbols, 3709 num_symbol_entries)); 3710 return on_load_entry; 3711 } 3712 3713 // Find the JVM_OnLoad entry point 3714 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3715 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3716 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3717 } 3718 3719 // Find the Agent_OnLoad entry point 3720 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3721 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3722 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3723 } 3724 3725 // For backwards compatibility with -Xrun 3726 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3727 // treated like -agentpath: 3728 // Must be called before agent libraries are created 3729 void Threads::convert_vm_init_libraries_to_agents() { 3730 AgentLibrary* agent; 3731 AgentLibrary* next; 3732 3733 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3734 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3735 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3736 3737 // If there is an JVM_OnLoad function it will get called later, 3738 // otherwise see if there is an Agent_OnLoad 3739 if (on_load_entry == NULL) { 3740 on_load_entry = lookup_agent_on_load(agent); 3741 if (on_load_entry != NULL) { 3742 // switch it to the agent list -- so that Agent_OnLoad will be called, 3743 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3744 Arguments::convert_library_to_agent(agent); 3745 } else { 3746 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3747 } 3748 } 3749 } 3750 } 3751 3752 // Create agents for -agentlib: -agentpath: and converted -Xrun 3753 // Invokes Agent_OnLoad 3754 // Called very early -- before JavaThreads exist 3755 void Threads::create_vm_init_agents() { 3756 extern struct JavaVM_ main_vm; 3757 AgentLibrary* agent; 3758 3759 JvmtiExport::enter_onload_phase(); 3760 3761 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3762 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3763 3764 if (on_load_entry != NULL) { 3765 // Invoke the Agent_OnLoad function 3766 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3767 if (err != JNI_OK) { 3768 vm_exit_during_initialization("agent library failed to init", agent->name()); 3769 } 3770 } else { 3771 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3772 } 3773 } 3774 JvmtiExport::enter_primordial_phase(); 3775 } 3776 3777 extern "C" { 3778 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3779 } 3780 3781 void Threads::shutdown_vm_agents() { 3782 // Send any Agent_OnUnload notifications 3783 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3784 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3785 extern struct JavaVM_ main_vm; 3786 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3787 3788 // Find the Agent_OnUnload function. 3789 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3790 os::find_agent_function(agent, 3791 false, 3792 on_unload_symbols, 3793 num_symbol_entries)); 3794 3795 // Invoke the Agent_OnUnload function 3796 if (unload_entry != NULL) { 3797 JavaThread* thread = JavaThread::current(); 3798 ThreadToNativeFromVM ttn(thread); 3799 HandleMark hm(thread); 3800 (*unload_entry)(&main_vm); 3801 } 3802 } 3803 } 3804 3805 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3806 // Invokes JVM_OnLoad 3807 void Threads::create_vm_init_libraries() { 3808 extern struct JavaVM_ main_vm; 3809 AgentLibrary* agent; 3810 3811 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3812 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3813 3814 if (on_load_entry != NULL) { 3815 // Invoke the JVM_OnLoad function 3816 JavaThread* thread = JavaThread::current(); 3817 ThreadToNativeFromVM ttn(thread); 3818 HandleMark hm(thread); 3819 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3820 if (err != JNI_OK) { 3821 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3822 } 3823 } else { 3824 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3825 } 3826 } 3827 } 3828 3829 // Last thread running calls java.lang.Shutdown.shutdown() 3830 void JavaThread::invoke_shutdown_hooks() { 3831 HandleMark hm(this); 3832 3833 // We could get here with a pending exception, if so clear it now. 3834 if (this->has_pending_exception()) { 3835 this->clear_pending_exception(); 3836 } 3837 3838 EXCEPTION_MARK; 3839 Klass* k = 3840 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3841 THREAD); 3842 if (k != NULL) { 3843 // SystemDictionary::resolve_or_null will return null if there was 3844 // an exception. If we cannot load the Shutdown class, just don't 3845 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3846 // and finalizers (if runFinalizersOnExit is set) won't be run. 3847 // Note that if a shutdown hook was registered or runFinalizersOnExit 3848 // was called, the Shutdown class would have already been loaded 3849 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3850 instanceKlassHandle shutdown_klass (THREAD, k); 3851 JavaValue result(T_VOID); 3852 JavaCalls::call_static(&result, 3853 shutdown_klass, 3854 vmSymbols::shutdown_method_name(), 3855 vmSymbols::void_method_signature(), 3856 THREAD); 3857 } 3858 CLEAR_PENDING_EXCEPTION; 3859 } 3860 3861 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3862 // the program falls off the end of main(). Another VM exit path is through 3863 // vm_exit() when the program calls System.exit() to return a value or when 3864 // there is a serious error in VM. The two shutdown paths are not exactly 3865 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3866 // and VM_Exit op at VM level. 3867 // 3868 // Shutdown sequence: 3869 // + Shutdown native memory tracking if it is on 3870 // + Wait until we are the last non-daemon thread to execute 3871 // <-- every thing is still working at this moment --> 3872 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3873 // shutdown hooks, run finalizers if finalization-on-exit 3874 // + Call before_exit(), prepare for VM exit 3875 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3876 // currently the only user of this mechanism is File.deleteOnExit()) 3877 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3878 // post thread end and vm death events to JVMTI, 3879 // stop signal thread 3880 // + Call JavaThread::exit(), it will: 3881 // > release JNI handle blocks, remove stack guard pages 3882 // > remove this thread from Threads list 3883 // <-- no more Java code from this thread after this point --> 3884 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3885 // the compiler threads at safepoint 3886 // <-- do not use anything that could get blocked by Safepoint --> 3887 // + Disable tracing at JNI/JVM barriers 3888 // + Set _vm_exited flag for threads that are still running native code 3889 // + Delete this thread 3890 // + Call exit_globals() 3891 // > deletes tty 3892 // > deletes PerfMemory resources 3893 // + Return to caller 3894 3895 bool Threads::destroy_vm() { 3896 JavaThread* thread = JavaThread::current(); 3897 3898 #ifdef ASSERT 3899 _vm_complete = false; 3900 #endif 3901 // Wait until we are the last non-daemon thread to execute 3902 { MutexLocker nu(Threads_lock); 3903 while (Threads::number_of_non_daemon_threads() > 1) 3904 // This wait should make safepoint checks, wait without a timeout, 3905 // and wait as a suspend-equivalent condition. 3906 // 3907 // Note: If the FlatProfiler is running and this thread is waiting 3908 // for another non-daemon thread to finish, then the FlatProfiler 3909 // is waiting for the external suspend request on this thread to 3910 // complete. wait_for_ext_suspend_completion() will eventually 3911 // timeout, but that takes time. Making this wait a suspend- 3912 // equivalent condition solves that timeout problem. 3913 // 3914 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3915 Mutex::_as_suspend_equivalent_flag); 3916 } 3917 3918 // Hang forever on exit if we are reporting an error. 3919 if (ShowMessageBoxOnError && is_error_reported()) { 3920 os::infinite_sleep(); 3921 } 3922 os::wait_for_keypress_at_exit(); 3923 3924 // run Java level shutdown hooks 3925 thread->invoke_shutdown_hooks(); 3926 3927 before_exit(thread); 3928 3929 thread->exit(true); 3930 3931 // Stop VM thread. 3932 { 3933 // 4945125 The vm thread comes to a safepoint during exit. 3934 // GC vm_operations can get caught at the safepoint, and the 3935 // heap is unparseable if they are caught. Grab the Heap_lock 3936 // to prevent this. The GC vm_operations will not be able to 3937 // queue until after the vm thread is dead. After this point, 3938 // we'll never emerge out of the safepoint before the VM exits. 3939 3940 MutexLocker ml(Heap_lock); 3941 3942 VMThread::wait_for_vm_thread_exit(); 3943 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3944 VMThread::destroy(); 3945 } 3946 3947 // clean up ideal graph printers 3948 #if defined(COMPILER2) && !defined(PRODUCT) 3949 IdealGraphPrinter::clean_up(); 3950 #endif 3951 3952 // Now, all Java threads are gone except daemon threads. Daemon threads 3953 // running Java code or in VM are stopped by the Safepoint. However, 3954 // daemon threads executing native code are still running. But they 3955 // will be stopped at native=>Java/VM barriers. Note that we can't 3956 // simply kill or suspend them, as it is inherently deadlock-prone. 3957 3958 #ifndef PRODUCT 3959 // disable function tracing at JNI/JVM barriers 3960 TraceJNICalls = false; 3961 TraceJVMCalls = false; 3962 TraceRuntimeCalls = false; 3963 #endif 3964 3965 VM_Exit::set_vm_exited(); 3966 3967 notify_vm_shutdown(); 3968 3969 delete thread; 3970 3971 // exit_globals() will delete tty 3972 exit_globals(); 3973 3974 return true; 3975 } 3976 3977 3978 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 3979 if (version == JNI_VERSION_1_1) return JNI_TRUE; 3980 return is_supported_jni_version(version); 3981 } 3982 3983 3984 jboolean Threads::is_supported_jni_version(jint version) { 3985 if (version == JNI_VERSION_1_2) return JNI_TRUE; 3986 if (version == JNI_VERSION_1_4) return JNI_TRUE; 3987 if (version == JNI_VERSION_1_6) return JNI_TRUE; 3988 if (version == JNI_VERSION_1_8) return JNI_TRUE; 3989 return JNI_FALSE; 3990 } 3991 3992 3993 void Threads::add(JavaThread* p, bool force_daemon) { 3994 // The threads lock must be owned at this point 3995 assert_locked_or_safepoint(Threads_lock); 3996 3997 // See the comment for this method in thread.hpp for its purpose and 3998 // why it is called here. 3999 p->initialize_queues(); 4000 p->set_next(_thread_list); 4001 _thread_list = p; 4002 _number_of_threads++; 4003 oop threadObj = p->threadObj(); 4004 bool daemon = true; 4005 // Bootstrapping problem: threadObj can be null for initial 4006 // JavaThread (or for threads attached via JNI) 4007 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4008 _number_of_non_daemon_threads++; 4009 daemon = false; 4010 } 4011 4012 p->set_safepoint_visible(true); 4013 4014 ThreadService::add_thread(p, daemon); 4015 4016 // Possible GC point. 4017 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4018 } 4019 4020 void Threads::remove(JavaThread* p) { 4021 // Extra scope needed for Thread_lock, so we can check 4022 // that we do not remove thread without safepoint code notice 4023 { MutexLocker ml(Threads_lock); 4024 4025 assert(includes(p), "p must be present"); 4026 4027 JavaThread* current = _thread_list; 4028 JavaThread* prev = NULL; 4029 4030 while (current != p) { 4031 prev = current; 4032 current = current->next(); 4033 } 4034 4035 if (prev) { 4036 prev->set_next(current->next()); 4037 } else { 4038 _thread_list = p->next(); 4039 } 4040 _number_of_threads--; 4041 oop threadObj = p->threadObj(); 4042 bool daemon = true; 4043 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4044 _number_of_non_daemon_threads--; 4045 daemon = false; 4046 4047 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4048 // on destroy_vm will wake up. 4049 if (number_of_non_daemon_threads() == 1) 4050 Threads_lock->notify_all(); 4051 } 4052 ThreadService::remove_thread(p, daemon); 4053 4054 // Make sure that safepoint code disregard this thread. This is needed since 4055 // the thread might mess around with locks after this point. This can cause it 4056 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4057 // of this thread since it is removed from the queue. 4058 p->set_terminated_value(); 4059 4060 // Now, this thread is not visible to safepoint 4061 p->set_safepoint_visible(false); 4062 // once the thread becomes safepoint invisible, we can not use its per-thread 4063 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4064 // to release its per-thread recorder here. 4065 MemTracker::thread_exiting(p); 4066 } // unlock Threads_lock 4067 4068 // Since Events::log uses a lock, we grab it outside the Threads_lock 4069 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4070 } 4071 4072 // Threads_lock must be held when this is called (or must be called during a safepoint) 4073 bool Threads::includes(JavaThread* p) { 4074 assert(Threads_lock->is_locked(), "sanity check"); 4075 ALL_JAVA_THREADS(q) { 4076 if (q == p) { 4077 return true; 4078 } 4079 } 4080 return false; 4081 } 4082 4083 // Operations on the Threads list for GC. These are not explicitly locked, 4084 // but the garbage collector must provide a safe context for them to run. 4085 // In particular, these things should never be called when the Threads_lock 4086 // is held by some other thread. (Note: the Safepoint abstraction also 4087 // uses the Threads_lock to guarantee this property. It also makes sure that 4088 // all threads gets blocked when exiting or starting). 4089 4090 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4091 ALL_JAVA_THREADS(p) { 4092 p->oops_do(f, cld_f, cf); 4093 } 4094 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4095 } 4096 4097 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4098 // Introduce a mechanism allowing parallel threads to claim threads as 4099 // root groups. Overhead should be small enough to use all the time, 4100 // even in sequential code. 4101 SharedHeap* sh = SharedHeap::heap(); 4102 // Cannot yet substitute active_workers for n_par_threads 4103 // because of G1CollectedHeap::verify() use of 4104 // SharedHeap::process_roots(). n_par_threads == 0 will 4105 // turn off parallelism in process_roots while active_workers 4106 // is being used for parallelism elsewhere. 4107 bool is_par = sh->n_par_threads() > 0; 4108 assert(!is_par || 4109 (SharedHeap::heap()->n_par_threads() == 4110 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4111 int cp = SharedHeap::heap()->strong_roots_parity(); 4112 ALL_JAVA_THREADS(p) { 4113 if (p->claim_oops_do(is_par, cp)) { 4114 p->oops_do(f, cld_f, cf); 4115 } 4116 } 4117 VMThread* vmt = VMThread::vm_thread(); 4118 if (vmt->claim_oops_do(is_par, cp)) { 4119 vmt->oops_do(f, cld_f, cf); 4120 } 4121 } 4122 4123 #if INCLUDE_ALL_GCS 4124 // Used by ParallelScavenge 4125 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4126 ALL_JAVA_THREADS(p) { 4127 q->enqueue(new ThreadRootsTask(p)); 4128 } 4129 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4130 } 4131 4132 // Used by Parallel Old 4133 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4134 ALL_JAVA_THREADS(p) { 4135 q->enqueue(new ThreadRootsMarkingTask(p)); 4136 } 4137 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4138 } 4139 #endif // INCLUDE_ALL_GCS 4140 4141 void Threads::nmethods_do(CodeBlobClosure* cf) { 4142 ALL_JAVA_THREADS(p) { 4143 p->nmethods_do(cf); 4144 } 4145 VMThread::vm_thread()->nmethods_do(cf); 4146 } 4147 4148 void Threads::metadata_do(void f(Metadata*)) { 4149 ALL_JAVA_THREADS(p) { 4150 p->metadata_do(f); 4151 } 4152 } 4153 4154 void Threads::gc_epilogue() { 4155 ALL_JAVA_THREADS(p) { 4156 p->gc_epilogue(); 4157 } 4158 } 4159 4160 void Threads::gc_prologue() { 4161 ALL_JAVA_THREADS(p) { 4162 p->gc_prologue(); 4163 } 4164 } 4165 4166 void Threads::deoptimized_wrt_marked_nmethods() { 4167 ALL_JAVA_THREADS(p) { 4168 p->deoptimized_wrt_marked_nmethods(); 4169 } 4170 } 4171 4172 4173 // Get count Java threads that are waiting to enter the specified monitor. 4174 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4175 address monitor, bool doLock) { 4176 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4177 "must grab Threads_lock or be at safepoint"); 4178 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4179 4180 int i = 0; 4181 { 4182 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4183 ALL_JAVA_THREADS(p) { 4184 if (p->is_Compiler_thread()) continue; 4185 4186 address pending = (address)p->current_pending_monitor(); 4187 if (pending == monitor) { // found a match 4188 if (i < count) result->append(p); // save the first count matches 4189 i++; 4190 } 4191 } 4192 } 4193 return result; 4194 } 4195 4196 4197 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4198 assert(doLock || 4199 Threads_lock->owned_by_self() || 4200 SafepointSynchronize::is_at_safepoint(), 4201 "must grab Threads_lock or be at safepoint"); 4202 4203 // NULL owner means not locked so we can skip the search 4204 if (owner == NULL) return NULL; 4205 4206 { 4207 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4208 ALL_JAVA_THREADS(p) { 4209 // first, see if owner is the address of a Java thread 4210 if (owner == (address)p) return p; 4211 } 4212 } 4213 // Cannot assert on lack of success here since this function may be 4214 // used by code that is trying to report useful problem information 4215 // like deadlock detection. 4216 if (UseHeavyMonitors) return NULL; 4217 4218 // 4219 // If we didn't find a matching Java thread and we didn't force use of 4220 // heavyweight monitors, then the owner is the stack address of the 4221 // Lock Word in the owning Java thread's stack. 4222 // 4223 JavaThread* the_owner = NULL; 4224 { 4225 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4226 ALL_JAVA_THREADS(q) { 4227 if (q->is_lock_owned(owner)) { 4228 the_owner = q; 4229 break; 4230 } 4231 } 4232 } 4233 // cannot assert on lack of success here; see above comment 4234 return the_owner; 4235 } 4236 4237 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4238 void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4239 char buf[32]; 4240 st->print_cr("%s", os::local_time_string(buf, sizeof(buf))); 4241 4242 st->print_cr("Full thread dump %s (%s %s):", 4243 Abstract_VM_Version::vm_name(), 4244 Abstract_VM_Version::vm_release(), 4245 Abstract_VM_Version::vm_info_string() 4246 ); 4247 st->cr(); 4248 4249 #if INCLUDE_ALL_GCS 4250 // Dump concurrent locks 4251 ConcurrentLocksDump concurrent_locks; 4252 if (print_concurrent_locks) { 4253 concurrent_locks.dump_at_safepoint(); 4254 } 4255 #endif // INCLUDE_ALL_GCS 4256 4257 ALL_JAVA_THREADS(p) { 4258 ResourceMark rm; 4259 p->print_on(st); 4260 if (print_stacks) { 4261 if (internal_format) { 4262 p->trace_stack(); 4263 } else { 4264 p->print_stack_on(st); 4265 } 4266 } 4267 st->cr(); 4268 #if INCLUDE_ALL_GCS 4269 if (print_concurrent_locks) { 4270 concurrent_locks.print_locks_on(p, st); 4271 } 4272 #endif // INCLUDE_ALL_GCS 4273 } 4274 4275 VMThread::vm_thread()->print_on(st); 4276 st->cr(); 4277 Universe::heap()->print_gc_threads_on(st); 4278 WatcherThread* wt = WatcherThread::watcher_thread(); 4279 if (wt != NULL) { 4280 wt->print_on(st); 4281 st->cr(); 4282 } 4283 CompileBroker::print_compiler_threads_on(st); 4284 st->flush(); 4285 } 4286 4287 // Threads::print_on_error() is called by fatal error handler. It's possible 4288 // that VM is not at safepoint and/or current thread is inside signal handler. 4289 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4290 // memory (even in resource area), it might deadlock the error handler. 4291 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4292 bool found_current = false; 4293 st->print_cr("Java Threads: ( => current thread )"); 4294 ALL_JAVA_THREADS(thread) { 4295 bool is_current = (current == thread); 4296 found_current = found_current || is_current; 4297 4298 st->print("%s", is_current ? "=>" : " "); 4299 4300 st->print(PTR_FORMAT, thread); 4301 st->print(" "); 4302 thread->print_on_error(st, buf, buflen); 4303 st->cr(); 4304 } 4305 st->cr(); 4306 4307 st->print_cr("Other Threads:"); 4308 if (VMThread::vm_thread()) { 4309 bool is_current = (current == VMThread::vm_thread()); 4310 found_current = found_current || is_current; 4311 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4312 4313 st->print(PTR_FORMAT, VMThread::vm_thread()); 4314 st->print(" "); 4315 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4316 st->cr(); 4317 } 4318 WatcherThread* wt = WatcherThread::watcher_thread(); 4319 if (wt != NULL) { 4320 bool is_current = (current == wt); 4321 found_current = found_current || is_current; 4322 st->print("%s", is_current ? "=>" : " "); 4323 4324 st->print(PTR_FORMAT, wt); 4325 st->print(" "); 4326 wt->print_on_error(st, buf, buflen); 4327 st->cr(); 4328 } 4329 if (!found_current) { 4330 st->cr(); 4331 st->print("=>" PTR_FORMAT " (exited) ", current); 4332 current->print_on_error(st, buf, buflen); 4333 st->cr(); 4334 } 4335 } 4336 4337 // Internal SpinLock and Mutex 4338 // Based on ParkEvent 4339 4340 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4341 // 4342 // We employ SpinLocks _only for low-contention, fixed-length 4343 // short-duration critical sections where we're concerned 4344 // about native mutex_t or HotSpot Mutex:: latency. 4345 // The mux construct provides a spin-then-block mutual exclusion 4346 // mechanism. 4347 // 4348 // Testing has shown that contention on the ListLock guarding gFreeList 4349 // is common. If we implement ListLock as a simple SpinLock it's common 4350 // for the JVM to devolve to yielding with little progress. This is true 4351 // despite the fact that the critical sections protected by ListLock are 4352 // extremely short. 4353 // 4354 // TODO-FIXME: ListLock should be of type SpinLock. 4355 // We should make this a 1st-class type, integrated into the lock 4356 // hierarchy as leaf-locks. Critically, the SpinLock structure 4357 // should have sufficient padding to avoid false-sharing and excessive 4358 // cache-coherency traffic. 4359 4360 4361 typedef volatile int SpinLockT; 4362 4363 void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4364 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4365 return; // normal fast-path return 4366 } 4367 4368 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4369 TEVENT(SpinAcquire - ctx); 4370 int ctr = 0; 4371 int Yields = 0; 4372 for (;;) { 4373 while (*adr != 0) { 4374 ++ctr; 4375 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4376 if (Yields > 5) { 4377 os::naked_short_sleep(1); 4378 } else { 4379 os::NakedYield(); 4380 ++Yields; 4381 } 4382 } else { 4383 SpinPause(); 4384 } 4385 } 4386 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4387 } 4388 } 4389 4390 void Thread::SpinRelease (volatile int * adr) { 4391 assert(*adr != 0, "invariant"); 4392 OrderAccess::fence(); // guarantee at least release consistency. 4393 // Roach-motel semantics. 4394 // It's safe if subsequent LDs and STs float "up" into the critical section, 4395 // but prior LDs and STs within the critical section can't be allowed 4396 // to reorder or float past the ST that releases the lock. 4397 *adr = 0; 4398 } 4399 4400 // muxAcquire and muxRelease: 4401 // 4402 // * muxAcquire and muxRelease support a single-word lock-word construct. 4403 // The LSB of the word is set IFF the lock is held. 4404 // The remainder of the word points to the head of a singly-linked list 4405 // of threads blocked on the lock. 4406 // 4407 // * The current implementation of muxAcquire-muxRelease uses its own 4408 // dedicated Thread._MuxEvent instance. If we're interested in 4409 // minimizing the peak number of extant ParkEvent instances then 4410 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4411 // as certain invariants were satisfied. Specifically, care would need 4412 // to be taken with regards to consuming unpark() "permits". 4413 // A safe rule of thumb is that a thread would never call muxAcquire() 4414 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4415 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4416 // consume an unpark() permit intended for monitorenter, for instance. 4417 // One way around this would be to widen the restricted-range semaphore 4418 // implemented in park(). Another alternative would be to provide 4419 // multiple instances of the PlatformEvent() for each thread. One 4420 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4421 // 4422 // * Usage: 4423 // -- Only as leaf locks 4424 // -- for short-term locking only as muxAcquire does not perform 4425 // thread state transitions. 4426 // 4427 // Alternatives: 4428 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4429 // but with parking or spin-then-park instead of pure spinning. 4430 // * Use Taura-Oyama-Yonenzawa locks. 4431 // * It's possible to construct a 1-0 lock if we encode the lockword as 4432 // (List,LockByte). Acquire will CAS the full lockword while Release 4433 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4434 // acquiring threads use timers (ParkTimed) to detect and recover from 4435 // the stranding window. Thread/Node structures must be aligned on 256-byte 4436 // boundaries by using placement-new. 4437 // * Augment MCS with advisory back-link fields maintained with CAS(). 4438 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4439 // The validity of the backlinks must be ratified before we trust the value. 4440 // If the backlinks are invalid the exiting thread must back-track through the 4441 // the forward links, which are always trustworthy. 4442 // * Add a successor indication. The LockWord is currently encoded as 4443 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4444 // to provide the usual futile-wakeup optimization. 4445 // See RTStt for details. 4446 // * Consider schedctl.sc_nopreempt to cover the critical section. 4447 // 4448 4449 4450 typedef volatile intptr_t MutexT; // Mux Lock-word 4451 enum MuxBits { LOCKBIT = 1 }; 4452 4453 void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4454 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4455 if (w == 0) return; 4456 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4457 return; 4458 } 4459 4460 TEVENT(muxAcquire - Contention); 4461 ParkEvent * const Self = Thread::current()->_MuxEvent; 4462 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4463 for (;;) { 4464 int its = (os::is_MP() ? 100 : 0) + 1; 4465 4466 // Optional spin phase: spin-then-park strategy 4467 while (--its >= 0) { 4468 w = *Lock; 4469 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4470 return; 4471 } 4472 } 4473 4474 Self->reset(); 4475 Self->OnList = intptr_t(Lock); 4476 // The following fence() isn't _strictly necessary as the subsequent 4477 // CAS() both serializes execution and ratifies the fetched *Lock value. 4478 OrderAccess::fence(); 4479 for (;;) { 4480 w = *Lock; 4481 if ((w & LOCKBIT) == 0) { 4482 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4483 Self->OnList = 0; // hygiene - allows stronger asserts 4484 return; 4485 } 4486 continue; // Interference -- *Lock changed -- Just retry 4487 } 4488 assert(w & LOCKBIT, "invariant"); 4489 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4490 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4491 } 4492 4493 while (Self->OnList != 0) { 4494 Self->park(); 4495 } 4496 } 4497 } 4498 4499 void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4500 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4501 if (w == 0) return; 4502 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4503 return; 4504 } 4505 4506 TEVENT(muxAcquire - Contention); 4507 ParkEvent * ReleaseAfter = NULL; 4508 if (ev == NULL) { 4509 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4510 } 4511 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4512 for (;;) { 4513 guarantee(ev->OnList == 0, "invariant"); 4514 int its = (os::is_MP() ? 100 : 0) + 1; 4515 4516 // Optional spin phase: spin-then-park strategy 4517 while (--its >= 0) { 4518 w = *Lock; 4519 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4520 if (ReleaseAfter != NULL) { 4521 ParkEvent::Release(ReleaseAfter); 4522 } 4523 return; 4524 } 4525 } 4526 4527 ev->reset(); 4528 ev->OnList = intptr_t(Lock); 4529 // The following fence() isn't _strictly necessary as the subsequent 4530 // CAS() both serializes execution and ratifies the fetched *Lock value. 4531 OrderAccess::fence(); 4532 for (;;) { 4533 w = *Lock; 4534 if ((w & LOCKBIT) == 0) { 4535 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4536 ev->OnList = 0; 4537 // We call ::Release while holding the outer lock, thus 4538 // artificially lengthening the critical section. 4539 // Consider deferring the ::Release() until the subsequent unlock(), 4540 // after we've dropped the outer lock. 4541 if (ReleaseAfter != NULL) { 4542 ParkEvent::Release(ReleaseAfter); 4543 } 4544 return; 4545 } 4546 continue; // Interference -- *Lock changed -- Just retry 4547 } 4548 assert(w & LOCKBIT, "invariant"); 4549 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4550 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4551 } 4552 4553 while (ev->OnList != 0) { 4554 ev->park(); 4555 } 4556 } 4557 } 4558 4559 // Release() must extract a successor from the list and then wake that thread. 4560 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4561 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4562 // Release() would : 4563 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4564 // (B) Extract a successor from the private list "in-hand" 4565 // (C) attempt to CAS() the residual back into *Lock over null. 4566 // If there were any newly arrived threads and the CAS() would fail. 4567 // In that case Release() would detach the RATs, re-merge the list in-hand 4568 // with the RATs and repeat as needed. Alternately, Release() might 4569 // detach and extract a successor, but then pass the residual list to the wakee. 4570 // The wakee would be responsible for reattaching and remerging before it 4571 // competed for the lock. 4572 // 4573 // Both "pop" and DMR are immune from ABA corruption -- there can be 4574 // multiple concurrent pushers, but only one popper or detacher. 4575 // This implementation pops from the head of the list. This is unfair, 4576 // but tends to provide excellent throughput as hot threads remain hot. 4577 // (We wake recently run threads first). 4578 4579 void Thread::muxRelease (volatile intptr_t * Lock) { 4580 for (;;) { 4581 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4582 assert(w & LOCKBIT, "invariant"); 4583 if (w == LOCKBIT) return; 4584 ParkEvent * List = (ParkEvent *)(w & ~LOCKBIT); 4585 assert(List != NULL, "invariant"); 4586 assert(List->OnList == intptr_t(Lock), "invariant"); 4587 ParkEvent * nxt = List->ListNext; 4588 4589 // The following CAS() releases the lock and pops the head element. 4590 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4591 continue; 4592 } 4593 List->OnList = 0; 4594 OrderAccess::fence(); 4595 List->unpark(); 4596 return; 4597 } 4598 } 4599 4600 4601 void Threads::verify() { 4602 ALL_JAVA_THREADS(p) { 4603 p->verify(); 4604 } 4605 VMThread* thread = VMThread::vm_thread(); 4606 if (thread != NULL) thread->verify(); 4607 }