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/codeCache.hpp" 31 #include "code/scopeDesc.hpp" 32 #include "compiler/compileBroker.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "interpreter/linkResolver.hpp" 35 #include "interpreter/oopMapCache.hpp" 36 #include "jvmtifiles/jvmtiEnv.hpp" 37 #include "memory/gcLocker.inline.hpp" 38 #include "memory/metaspaceShared.hpp" 39 #include "memory/oopFactory.hpp" 40 #include "memory/universe.inline.hpp" 41 #include "oops/instanceKlass.hpp" 42 #include "oops/objArrayOop.hpp" 43 #include "oops/oop.inline.hpp" 44 #include "oops/symbol.hpp" 45 #include "prims/jvm_misc.hpp" 46 #include "prims/jvmtiExport.hpp" 47 #include "prims/jvmtiThreadState.hpp" 48 #include "prims/privilegedStack.hpp" 49 #include "runtime/arguments.hpp" 50 #include "runtime/atomic.inline.hpp" 51 #include "runtime/biasedLocking.hpp" 52 #include "runtime/deoptimization.hpp" 53 #include "runtime/fprofiler.hpp" 54 #include "runtime/frame.inline.hpp" 55 #include "runtime/init.hpp" 56 #include "runtime/interfaceSupport.hpp" 57 #include "runtime/java.hpp" 58 #include "runtime/javaCalls.hpp" 59 #include "runtime/jniPeriodicChecker.hpp" 60 #include "runtime/memprofiler.hpp" 61 #include "runtime/mutexLocker.hpp" 62 #include "runtime/objectMonitor.hpp" 63 #include "runtime/orderAccess.inline.hpp" 64 #include "runtime/osThread.hpp" 65 #include "runtime/safepoint.hpp" 66 #include "runtime/sharedRuntime.hpp" 67 #include "runtime/statSampler.hpp" 68 #include "runtime/stubRoutines.hpp" 69 #include "runtime/sweeper.hpp" 70 #include "runtime/task.hpp" 71 #include "runtime/thread.inline.hpp" 72 #include "runtime/threadCritical.hpp" 73 #include "runtime/threadLocalStorage.hpp" 74 #include "runtime/vframe.hpp" 75 #include "runtime/vframeArray.hpp" 76 #include "runtime/vframe_hp.hpp" 77 #include "runtime/vmThread.hpp" 78 #include "runtime/vm_operations.hpp" 79 #include "runtime/vm_version.hpp" 80 #include "services/attachListener.hpp" 81 #include "services/management.hpp" 82 #include "services/memTracker.hpp" 83 #include "services/threadService.hpp" 84 #include "trace/tracing.hpp" 85 #include "trace/traceMacros.hpp" 86 #include "utilities/defaultStream.hpp" 87 #include "utilities/dtrace.hpp" 88 #include "utilities/events.hpp" 89 #include "utilities/preserveException.hpp" 90 #include "utilities/macros.hpp" 91 #if INCLUDE_ALL_GCS 92 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 93 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 94 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 95 #endif // INCLUDE_ALL_GCS 96 #ifdef COMPILER1 97 #include "c1/c1_Compiler.hpp" 98 #endif 99 #ifdef COMPILER2 100 #include "opto/c2compiler.hpp" 101 #include "opto/idealGraphPrinter.hpp" 102 #endif 103 #if INCLUDE_RTM_OPT 104 #include "runtime/rtmLocking.hpp" 105 #endif 106 107 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 108 109 #ifdef DTRACE_ENABLED 110 111 // Only bother with this argument setup if dtrace is available 112 113 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 114 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 115 116 #define DTRACE_THREAD_PROBE(probe, javathread) \ 117 { \ 118 ResourceMark rm(this); \ 119 int len = 0; \ 120 const char* name = (javathread)->get_thread_name(); \ 121 len = strlen(name); \ 122 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 123 (char *) name, len, \ 124 java_lang_Thread::thread_id((javathread)->threadObj()), \ 125 (uintptr_t) (javathread)->osthread()->thread_id(), \ 126 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 127 } 128 129 #else // ndef DTRACE_ENABLED 130 131 #define DTRACE_THREAD_PROBE(probe, javathread) 132 133 #endif // ndef DTRACE_ENABLED 134 135 136 // Class hierarchy 137 // - Thread 138 // - VMThread 139 // - WatcherThread 140 // - ConcurrentMarkSweepThread 141 // - JavaThread 142 // - CompilerThread 143 144 // ======= Thread ======== 145 // Support for forcing alignment of thread objects for biased locking 146 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 147 if (UseBiasedLocking) { 148 const int alignment = markOopDesc::biased_lock_alignment; 149 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 150 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 151 : AllocateHeap(aligned_size, flags, CURRENT_PC, 152 AllocFailStrategy::RETURN_NULL); 153 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 154 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 155 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 156 "JavaThread alignment code overflowed allocated storage"); 157 if (TraceBiasedLocking) { 158 if (aligned_addr != real_malloc_addr) { 159 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 160 real_malloc_addr, aligned_addr); 161 } 162 } 163 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 164 return aligned_addr; 165 } else { 166 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 167 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 168 } 169 } 170 171 void Thread::operator delete(void* p) { 172 if (UseBiasedLocking) { 173 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 174 FreeHeap(real_malloc_addr, mtThread); 175 } else { 176 FreeHeap(p, mtThread); 177 } 178 } 179 180 181 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 182 // JavaThread 183 184 185 Thread::Thread() { 186 // stack and get_thread 187 set_stack_base(NULL); 188 set_stack_size(0); 189 set_self_raw_id(0); 190 set_lgrp_id(-1); 191 192 // allocated data structures 193 set_osthread(NULL); 194 set_resource_area(new (mtThread)ResourceArea()); 195 DEBUG_ONLY(_current_resource_mark = NULL;) 196 set_handle_area(new (mtThread) HandleArea(NULL)); 197 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 198 set_active_handles(NULL); 199 set_free_handle_block(NULL); 200 set_last_handle_mark(NULL); 201 202 // This initial value ==> never claimed. 203 _oops_do_parity = 0; 204 205 // the handle mark links itself to last_handle_mark 206 new HandleMark(this); 207 208 // plain initialization 209 debug_only(_owned_locks = NULL;) 210 debug_only(_allow_allocation_count = 0;) 211 NOT_PRODUCT(_allow_safepoint_count = 0;) 212 NOT_PRODUCT(_skip_gcalot = false;) 213 _jvmti_env_iteration_count = 0; 214 set_allocated_bytes(0); 215 _vm_operation_started_count = 0; 216 _vm_operation_completed_count = 0; 217 _current_pending_monitor = NULL; 218 _current_pending_monitor_is_from_java = true; 219 _current_waiting_monitor = NULL; 220 _num_nested_signal = 0; 221 omFreeList = NULL; 222 omFreeCount = 0; 223 omFreeProvision = 32; 224 omInUseList = NULL; 225 omInUseCount = 0; 226 227 #ifdef ASSERT 228 _visited_for_critical_count = false; 229 #endif 230 231 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 232 _suspend_flags = 0; 233 234 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 235 _hashStateX = os::random(); 236 _hashStateY = 842502087; 237 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 238 _hashStateW = 273326509; 239 240 _OnTrap = 0; 241 _schedctl = NULL; 242 _Stalled = 0; 243 _TypeTag = 0x2BAD; 244 245 // Many of the following fields are effectively final - immutable 246 // Note that nascent threads can't use the Native Monitor-Mutex 247 // construct until the _MutexEvent is initialized ... 248 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 249 // we might instead use a stack of ParkEvents that we could provision on-demand. 250 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 251 // and ::Release() 252 _ParkEvent = ParkEvent::Allocate(this); 253 _SleepEvent = ParkEvent::Allocate(this); 254 _MutexEvent = ParkEvent::Allocate(this); 255 _MuxEvent = ParkEvent::Allocate(this); 256 257 #ifdef CHECK_UNHANDLED_OOPS 258 if (CheckUnhandledOops) { 259 _unhandled_oops = new UnhandledOops(this); 260 } 261 #endif // CHECK_UNHANDLED_OOPS 262 #ifdef ASSERT 263 if (UseBiasedLocking) { 264 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 265 assert(this == _real_malloc_address || 266 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 267 "bug in forced alignment of thread objects"); 268 } 269 #endif // ASSERT 270 } 271 272 void Thread::initialize_thread_local_storage() { 273 // Note: Make sure this method only calls 274 // non-blocking operations. Otherwise, it might not work 275 // with the thread-startup/safepoint interaction. 276 277 // During Java thread startup, safepoint code should allow this 278 // method to complete because it may need to allocate memory to 279 // store information for the new thread. 280 281 // initialize structure dependent on thread local storage 282 ThreadLocalStorage::set_thread(this); 283 } 284 285 void Thread::record_stack_base_and_size() { 286 set_stack_base(os::current_stack_base()); 287 set_stack_size(os::current_stack_size()); 288 if (is_Java_thread()) { 289 ((JavaThread*) this)->set_stack_overflow_limit(); 290 } 291 // CR 7190089: on Solaris, primordial thread's stack is adjusted 292 // in initialize_thread(). Without the adjustment, stack size is 293 // incorrect if stack is set to unlimited (ulimit -s unlimited). 294 // So far, only Solaris has real implementation of initialize_thread(). 295 // 296 // set up any platform-specific state. 297 os::initialize_thread(this); 298 299 #if INCLUDE_NMT 300 // record thread's native stack, stack grows downward 301 address stack_low_addr = stack_base() - stack_size(); 302 MemTracker::record_thread_stack(stack_low_addr, stack_size()); 303 #endif // INCLUDE_NMT 304 } 305 306 307 Thread::~Thread() { 308 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 309 ObjectSynchronizer::omFlush(this); 310 311 EVENT_THREAD_DESTRUCT(this); 312 313 // stack_base can be NULL if the thread is never started or exited before 314 // record_stack_base_and_size called. Although, we would like to ensure 315 // that all started threads do call record_stack_base_and_size(), there is 316 // not proper way to enforce that. 317 #if INCLUDE_NMT 318 if (_stack_base != NULL) { 319 address low_stack_addr = stack_base() - stack_size(); 320 MemTracker::release_thread_stack(low_stack_addr, stack_size()); 321 #ifdef ASSERT 322 set_stack_base(NULL); 323 #endif 324 } 325 #endif // INCLUDE_NMT 326 327 // deallocate data structures 328 delete resource_area(); 329 // since the handle marks are using the handle area, we have to deallocated the root 330 // handle mark before deallocating the thread's handle area, 331 assert(last_handle_mark() != NULL, "check we have an element"); 332 delete last_handle_mark(); 333 assert(last_handle_mark() == NULL, "check we have reached the end"); 334 335 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 336 // We NULL out the fields for good hygiene. 337 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 338 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 339 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 340 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 341 342 delete handle_area(); 343 delete metadata_handles(); 344 345 // osthread() can be NULL, if creation of thread failed. 346 if (osthread() != NULL) os::free_thread(osthread()); 347 348 delete _SR_lock; 349 350 // clear thread local storage if the Thread is deleting itself 351 if (this == Thread::current()) { 352 ThreadLocalStorage::set_thread(NULL); 353 } else { 354 // In the case where we're not the current thread, invalidate all the 355 // caches in case some code tries to get the current thread or the 356 // thread that was destroyed, and gets stale information. 357 ThreadLocalStorage::invalidate_all(); 358 } 359 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 360 } 361 362 // NOTE: dummy function for assertion purpose. 363 void Thread::run() { 364 ShouldNotReachHere(); 365 } 366 367 #ifdef ASSERT 368 // Private method to check for dangling thread pointer 369 void check_for_dangling_thread_pointer(Thread *thread) { 370 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 371 "possibility of dangling Thread pointer"); 372 } 373 #endif 374 375 376 #ifndef PRODUCT 377 // Tracing method for basic thread operations 378 void Thread::trace(const char* msg, const Thread* const thread) { 379 if (!TraceThreadEvents) return; 380 ResourceMark rm; 381 ThreadCritical tc; 382 const char *name = "non-Java thread"; 383 int prio = -1; 384 if (thread->is_Java_thread() 385 && !thread->is_Compiler_thread()) { 386 // The Threads_lock must be held to get information about 387 // this thread but may not be in some situations when 388 // tracing thread events. 389 bool release_Threads_lock = false; 390 if (!Threads_lock->owned_by_self()) { 391 Threads_lock->lock(); 392 release_Threads_lock = true; 393 } 394 JavaThread* jt = (JavaThread *)thread; 395 name = (char *)jt->get_thread_name(); 396 oop thread_oop = jt->threadObj(); 397 if (thread_oop != NULL) { 398 prio = java_lang_Thread::priority(thread_oop); 399 } 400 if (release_Threads_lock) { 401 Threads_lock->unlock(); 402 } 403 } 404 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 405 } 406 #endif 407 408 409 ThreadPriority Thread::get_priority(const Thread* const thread) { 410 trace("get priority", thread); 411 ThreadPriority priority; 412 // Can return an error! 413 (void)os::get_priority(thread, priority); 414 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 415 return priority; 416 } 417 418 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 419 trace("set priority", thread); 420 debug_only(check_for_dangling_thread_pointer(thread);) 421 // Can return an error! 422 (void)os::set_priority(thread, priority); 423 } 424 425 426 void Thread::start(Thread* thread) { 427 trace("start", thread); 428 // Start is different from resume in that its safety is guaranteed by context or 429 // being called from a Java method synchronized on the Thread object. 430 if (!DisableStartThread) { 431 if (thread->is_Java_thread()) { 432 // Initialize the thread state to RUNNABLE before starting this thread. 433 // Can not set it after the thread started because we do not know the 434 // exact thread state at that time. It could be in MONITOR_WAIT or 435 // in SLEEPING or some other state. 436 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 437 java_lang_Thread::RUNNABLE); 438 } 439 os::start_thread(thread); 440 } 441 } 442 443 // Enqueue a VM_Operation to do the job for us - sometime later 444 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 445 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 446 VMThread::execute(vm_stop); 447 } 448 449 450 // Check if an external suspend request has completed (or has been 451 // cancelled). Returns true if the thread is externally suspended and 452 // false otherwise. 453 // 454 // The bits parameter returns information about the code path through 455 // the routine. Useful for debugging: 456 // 457 // set in is_ext_suspend_completed(): 458 // 0x00000001 - routine was entered 459 // 0x00000010 - routine return false at end 460 // 0x00000100 - thread exited (return false) 461 // 0x00000200 - suspend request cancelled (return false) 462 // 0x00000400 - thread suspended (return true) 463 // 0x00001000 - thread is in a suspend equivalent state (return true) 464 // 0x00002000 - thread is native and walkable (return true) 465 // 0x00004000 - thread is native_trans and walkable (needed retry) 466 // 467 // set in wait_for_ext_suspend_completion(): 468 // 0x00010000 - routine was entered 469 // 0x00020000 - suspend request cancelled before loop (return false) 470 // 0x00040000 - thread suspended before loop (return true) 471 // 0x00080000 - suspend request cancelled in loop (return false) 472 // 0x00100000 - thread suspended in loop (return true) 473 // 0x00200000 - suspend not completed during retry loop (return false) 474 475 // Helper class for tracing suspend wait debug bits. 476 // 477 // 0x00000100 indicates that the target thread exited before it could 478 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 479 // 0x00080000 each indicate a cancelled suspend request so they don't 480 // count as wait failures either. 481 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 482 483 class TraceSuspendDebugBits : public StackObj { 484 private: 485 JavaThread * jt; 486 bool is_wait; 487 bool called_by_wait; // meaningful when !is_wait 488 uint32_t * bits; 489 490 public: 491 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 492 uint32_t *_bits) { 493 jt = _jt; 494 is_wait = _is_wait; 495 called_by_wait = _called_by_wait; 496 bits = _bits; 497 } 498 499 ~TraceSuspendDebugBits() { 500 if (!is_wait) { 501 #if 1 502 // By default, don't trace bits for is_ext_suspend_completed() calls. 503 // That trace is very chatty. 504 return; 505 #else 506 if (!called_by_wait) { 507 // If tracing for is_ext_suspend_completed() is enabled, then only 508 // trace calls to it from wait_for_ext_suspend_completion() 509 return; 510 } 511 #endif 512 } 513 514 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 515 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 516 MutexLocker ml(Threads_lock); // needed for get_thread_name() 517 ResourceMark rm; 518 519 tty->print_cr( 520 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 521 jt->get_thread_name(), *bits); 522 523 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 524 } 525 } 526 } 527 }; 528 #undef DEBUG_FALSE_BITS 529 530 531 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 532 uint32_t *bits) { 533 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 534 535 bool did_trans_retry = false; // only do thread_in_native_trans retry once 536 bool do_trans_retry; // flag to force the retry 537 538 *bits |= 0x00000001; 539 540 do { 541 do_trans_retry = false; 542 543 if (is_exiting()) { 544 // Thread is in the process of exiting. This is always checked 545 // first to reduce the risk of dereferencing a freed JavaThread. 546 *bits |= 0x00000100; 547 return false; 548 } 549 550 if (!is_external_suspend()) { 551 // Suspend request is cancelled. This is always checked before 552 // is_ext_suspended() to reduce the risk of a rogue resume 553 // confusing the thread that made the suspend request. 554 *bits |= 0x00000200; 555 return false; 556 } 557 558 if (is_ext_suspended()) { 559 // thread is suspended 560 *bits |= 0x00000400; 561 return true; 562 } 563 564 // Now that we no longer do hard suspends of threads running 565 // native code, the target thread can be changing thread state 566 // while we are in this routine: 567 // 568 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 569 // 570 // We save a copy of the thread state as observed at this moment 571 // and make our decision about suspend completeness based on the 572 // copy. This closes the race where the thread state is seen as 573 // _thread_in_native_trans in the if-thread_blocked check, but is 574 // seen as _thread_blocked in if-thread_in_native_trans check. 575 JavaThreadState save_state = thread_state(); 576 577 if (save_state == _thread_blocked && is_suspend_equivalent()) { 578 // If the thread's state is _thread_blocked and this blocking 579 // condition is known to be equivalent to a suspend, then we can 580 // consider the thread to be externally suspended. This means that 581 // the code that sets _thread_blocked has been modified to do 582 // self-suspension if the blocking condition releases. We also 583 // used to check for CONDVAR_WAIT here, but that is now covered by 584 // the _thread_blocked with self-suspension check. 585 // 586 // Return true since we wouldn't be here unless there was still an 587 // external suspend request. 588 *bits |= 0x00001000; 589 return true; 590 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 591 // Threads running native code will self-suspend on native==>VM/Java 592 // transitions. If its stack is walkable (should always be the case 593 // unless this function is called before the actual java_suspend() 594 // call), then the wait is done. 595 *bits |= 0x00002000; 596 return true; 597 } else if (!called_by_wait && !did_trans_retry && 598 save_state == _thread_in_native_trans && 599 frame_anchor()->walkable()) { 600 // The thread is transitioning from thread_in_native to another 601 // thread state. check_safepoint_and_suspend_for_native_trans() 602 // will force the thread to self-suspend. If it hasn't gotten 603 // there yet we may have caught the thread in-between the native 604 // code check above and the self-suspend. Lucky us. If we were 605 // called by wait_for_ext_suspend_completion(), then it 606 // will be doing the retries so we don't have to. 607 // 608 // Since we use the saved thread state in the if-statement above, 609 // there is a chance that the thread has already transitioned to 610 // _thread_blocked by the time we get here. In that case, we will 611 // make a single unnecessary pass through the logic below. This 612 // doesn't hurt anything since we still do the trans retry. 613 614 *bits |= 0x00004000; 615 616 // Once the thread leaves thread_in_native_trans for another 617 // thread state, we break out of this retry loop. We shouldn't 618 // need this flag to prevent us from getting back here, but 619 // sometimes paranoia is good. 620 did_trans_retry = true; 621 622 // We wait for the thread to transition to a more usable state. 623 for (int i = 1; i <= SuspendRetryCount; i++) { 624 // We used to do an "os::yield_all(i)" call here with the intention 625 // that yielding would increase on each retry. However, the parameter 626 // is ignored on Linux which means the yield didn't scale up. Waiting 627 // on the SR_lock below provides a much more predictable scale up for 628 // the delay. It also provides a simple/direct point to check for any 629 // safepoint requests from the VMThread 630 631 // temporarily drops SR_lock while doing wait with safepoint check 632 // (if we're a JavaThread - the WatcherThread can also call this) 633 // and increase delay with each retry 634 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 635 636 // check the actual thread state instead of what we saved above 637 if (thread_state() != _thread_in_native_trans) { 638 // the thread has transitioned to another thread state so 639 // try all the checks (except this one) one more time. 640 do_trans_retry = true; 641 break; 642 } 643 } // end retry loop 644 645 646 } 647 } while (do_trans_retry); 648 649 *bits |= 0x00000010; 650 return false; 651 } 652 653 // Wait for an external suspend request to complete (or be cancelled). 654 // Returns true if the thread is externally suspended and false otherwise. 655 // 656 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 657 uint32_t *bits) { 658 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 659 false /* !called_by_wait */, bits); 660 661 // local flag copies to minimize SR_lock hold time 662 bool is_suspended; 663 bool pending; 664 uint32_t reset_bits; 665 666 // set a marker so is_ext_suspend_completed() knows we are the caller 667 *bits |= 0x00010000; 668 669 // We use reset_bits to reinitialize the bits value at the top of 670 // each retry loop. This allows the caller to make use of any 671 // unused bits for their own marking purposes. 672 reset_bits = *bits; 673 674 { 675 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 676 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 677 delay, bits); 678 pending = is_external_suspend(); 679 } 680 // must release SR_lock to allow suspension to complete 681 682 if (!pending) { 683 // A cancelled suspend request is the only false return from 684 // is_ext_suspend_completed() that keeps us from entering the 685 // retry loop. 686 *bits |= 0x00020000; 687 return false; 688 } 689 690 if (is_suspended) { 691 *bits |= 0x00040000; 692 return true; 693 } 694 695 for (int i = 1; i <= retries; i++) { 696 *bits = reset_bits; // reinit to only track last retry 697 698 // We used to do an "os::yield_all(i)" call here with the intention 699 // that yielding would increase on each retry. However, the parameter 700 // is ignored on Linux which means the yield didn't scale up. Waiting 701 // on the SR_lock below provides a much more predictable scale up for 702 // the delay. It also provides a simple/direct point to check for any 703 // safepoint requests from the VMThread 704 705 { 706 MutexLocker ml(SR_lock()); 707 // wait with safepoint check (if we're a JavaThread - the WatcherThread 708 // can also call this) and increase delay with each retry 709 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 710 711 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 712 delay, bits); 713 714 // It is possible for the external suspend request to be cancelled 715 // (by a resume) before the actual suspend operation is completed. 716 // Refresh our local copy to see if we still need to wait. 717 pending = is_external_suspend(); 718 } 719 720 if (!pending) { 721 // A cancelled suspend request is the only false return from 722 // is_ext_suspend_completed() that keeps us from staying in the 723 // retry loop. 724 *bits |= 0x00080000; 725 return false; 726 } 727 728 if (is_suspended) { 729 *bits |= 0x00100000; 730 return true; 731 } 732 } // end retry loop 733 734 // thread did not suspend after all our retries 735 *bits |= 0x00200000; 736 return false; 737 } 738 739 #ifndef PRODUCT 740 void JavaThread::record_jump(address target, address instr, const char* file, 741 int line) { 742 743 // This should not need to be atomic as the only way for simultaneous 744 // updates is via interrupts. Even then this should be rare or non-existent 745 // and we don't care that much anyway. 746 747 int index = _jmp_ring_index; 748 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 749 _jmp_ring[index]._target = (intptr_t) target; 750 _jmp_ring[index]._instruction = (intptr_t) instr; 751 _jmp_ring[index]._file = file; 752 _jmp_ring[index]._line = line; 753 } 754 #endif // PRODUCT 755 756 // Called by flat profiler 757 // Callers have already called wait_for_ext_suspend_completion 758 // The assertion for that is currently too complex to put here: 759 bool JavaThread::profile_last_Java_frame(frame* _fr) { 760 bool gotframe = false; 761 // self suspension saves needed state. 762 if (has_last_Java_frame() && _anchor.walkable()) { 763 *_fr = pd_last_frame(); 764 gotframe = true; 765 } 766 return gotframe; 767 } 768 769 void Thread::interrupt(Thread* thread) { 770 trace("interrupt", thread); 771 debug_only(check_for_dangling_thread_pointer(thread);) 772 os::interrupt(thread); 773 } 774 775 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 776 trace("is_interrupted", thread); 777 debug_only(check_for_dangling_thread_pointer(thread);) 778 // Note: If clear_interrupted==false, this simply fetches and 779 // returns the value of the field osthread()->interrupted(). 780 return os::is_interrupted(thread, clear_interrupted); 781 } 782 783 784 // GC Support 785 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 786 jint thread_parity = _oops_do_parity; 787 if (thread_parity != strong_roots_parity) { 788 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 789 if (res == thread_parity) { 790 return true; 791 } else { 792 guarantee(res == strong_roots_parity, "Or else what?"); 793 assert(SharedHeap::heap()->workers()->active_workers() > 0, 794 "Should only fail when parallel."); 795 return false; 796 } 797 } 798 assert(SharedHeap::heap()->workers()->active_workers() > 0, 799 "Should only fail when parallel."); 800 return false; 801 } 802 803 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 804 active_handles()->oops_do(f); 805 // Do oop for ThreadShadow 806 f->do_oop((oop*)&_pending_exception); 807 handle_area()->oops_do(f); 808 } 809 810 void Thread::nmethods_do(CodeBlobClosure* cf) { 811 // no nmethods in a generic thread... 812 } 813 814 void Thread::metadata_do(void f(Metadata*)) { 815 if (metadata_handles() != NULL) { 816 for (int i = 0; i< metadata_handles()->length(); i++) { 817 f(metadata_handles()->at(i)); 818 } 819 } 820 } 821 822 void Thread::print_on(outputStream* st) const { 823 // get_priority assumes osthread initialized 824 if (osthread() != NULL) { 825 int os_prio; 826 if (os::get_native_priority(this, &os_prio) == OS_OK) { 827 st->print("os_prio=%d ", os_prio); 828 } 829 st->print("tid=" INTPTR_FORMAT " ", this); 830 ext().print_on(st); 831 osthread()->print_on(st); 832 } 833 debug_only(if (WizardMode) print_owned_locks_on(st);) 834 } 835 836 // Thread::print_on_error() is called by fatal error handler. Don't use 837 // any lock or allocate memory. 838 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 839 if (is_VM_thread()) st->print("VMThread"); 840 else if (is_Compiler_thread()) st->print("CompilerThread"); 841 else if (is_Java_thread()) st->print("JavaThread"); 842 else if (is_GC_task_thread()) st->print("GCTaskThread"); 843 else if (is_Watcher_thread()) st->print("WatcherThread"); 844 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 845 else st->print("Thread"); 846 847 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 848 _stack_base - _stack_size, _stack_base); 849 850 if (osthread()) { 851 st->print(" [id=%d]", osthread()->thread_id()); 852 } 853 } 854 855 #ifdef ASSERT 856 void Thread::print_owned_locks_on(outputStream* st) const { 857 Monitor *cur = _owned_locks; 858 if (cur == NULL) { 859 st->print(" (no locks) "); 860 } else { 861 st->print_cr(" Locks owned:"); 862 while (cur) { 863 cur->print_on(st); 864 cur = cur->next(); 865 } 866 } 867 } 868 869 static int ref_use_count = 0; 870 871 bool Thread::owns_locks_but_compiled_lock() const { 872 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 873 if (cur != Compile_lock) return true; 874 } 875 return false; 876 } 877 878 879 #endif 880 881 #ifndef PRODUCT 882 883 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 884 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 885 // no threads which allow_vm_block's are held 886 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 887 // Check if current thread is allowed to block at a safepoint 888 if (!(_allow_safepoint_count == 0)) { 889 fatal("Possible safepoint reached by thread that does not allow it"); 890 } 891 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 892 fatal("LEAF method calling lock?"); 893 } 894 895 #ifdef ASSERT 896 if (potential_vm_operation && is_Java_thread() 897 && !Universe::is_bootstrapping()) { 898 // Make sure we do not hold any locks that the VM thread also uses. 899 // This could potentially lead to deadlocks 900 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 901 // Threads_lock is special, since the safepoint synchronization will not start before this is 902 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 903 // since it is used to transfer control between JavaThreads and the VMThread 904 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 905 if ((cur->allow_vm_block() && 906 cur != Threads_lock && 907 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 908 cur != VMOperationRequest_lock && 909 cur != VMOperationQueue_lock) || 910 cur->rank() == Mutex::special) { 911 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name())); 912 } 913 } 914 } 915 916 if (GCALotAtAllSafepoints) { 917 // We could enter a safepoint here and thus have a gc 918 InterfaceSupport::check_gc_alot(); 919 } 920 #endif 921 } 922 #endif 923 924 bool Thread::is_in_stack(address adr) const { 925 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 926 address end = os::current_stack_pointer(); 927 // Allow non Java threads to call this without stack_base 928 if (_stack_base == NULL) return true; 929 if (stack_base() >= adr && adr >= end) return true; 930 931 return false; 932 } 933 934 935 bool Thread::is_in_usable_stack(address adr) const { 936 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 937 size_t usable_stack_size = _stack_size - stack_guard_size; 938 939 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 940 } 941 942 943 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 944 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 945 // used for compilation in the future. If that change is made, the need for these methods 946 // should be revisited, and they should be removed if possible. 947 948 bool Thread::is_lock_owned(address adr) const { 949 return on_local_stack(adr); 950 } 951 952 bool Thread::set_as_starting_thread() { 953 // NOTE: this must be called inside the main thread. 954 return os::create_main_thread((JavaThread*)this); 955 } 956 957 static void initialize_class(Symbol* class_name, TRAPS) { 958 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 959 InstanceKlass::cast(klass)->initialize(CHECK); 960 } 961 962 963 // Creates the initial ThreadGroup 964 static Handle create_initial_thread_group(TRAPS) { 965 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 966 instanceKlassHandle klass (THREAD, k); 967 968 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 969 { 970 JavaValue result(T_VOID); 971 JavaCalls::call_special(&result, 972 system_instance, 973 klass, 974 vmSymbols::object_initializer_name(), 975 vmSymbols::void_method_signature(), 976 CHECK_NH); 977 } 978 Universe::set_system_thread_group(system_instance()); 979 980 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 981 { 982 JavaValue result(T_VOID); 983 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 984 JavaCalls::call_special(&result, 985 main_instance, 986 klass, 987 vmSymbols::object_initializer_name(), 988 vmSymbols::threadgroup_string_void_signature(), 989 system_instance, 990 string, 991 CHECK_NH); 992 } 993 return main_instance; 994 } 995 996 // Creates the initial Thread 997 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 998 TRAPS) { 999 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1000 instanceKlassHandle klass (THREAD, k); 1001 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1002 1003 java_lang_Thread::set_thread(thread_oop(), thread); 1004 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1005 thread->set_threadObj(thread_oop()); 1006 1007 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1008 1009 JavaValue result(T_VOID); 1010 JavaCalls::call_special(&result, thread_oop, 1011 klass, 1012 vmSymbols::object_initializer_name(), 1013 vmSymbols::threadgroup_string_void_signature(), 1014 thread_group, 1015 string, 1016 CHECK_NULL); 1017 return thread_oop(); 1018 } 1019 1020 static void call_initializeSystemClass(TRAPS) { 1021 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1022 instanceKlassHandle klass (THREAD, k); 1023 1024 JavaValue result(T_VOID); 1025 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1026 vmSymbols::void_method_signature(), CHECK); 1027 } 1028 1029 char java_runtime_name[128] = ""; 1030 char java_runtime_version[128] = ""; 1031 1032 // extract the JRE name from sun.misc.Version.java_runtime_name 1033 static const char* get_java_runtime_name(TRAPS) { 1034 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1035 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1036 fieldDescriptor fd; 1037 bool found = k != NULL && 1038 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1039 vmSymbols::string_signature(), &fd); 1040 if (found) { 1041 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1042 if (name_oop == NULL) { 1043 return NULL; 1044 } 1045 const char* name = java_lang_String::as_utf8_string(name_oop, 1046 java_runtime_name, 1047 sizeof(java_runtime_name)); 1048 return name; 1049 } else { 1050 return NULL; 1051 } 1052 } 1053 1054 // extract the JRE version from sun.misc.Version.java_runtime_version 1055 static const char* get_java_runtime_version(TRAPS) { 1056 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1057 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1058 fieldDescriptor fd; 1059 bool found = k != NULL && 1060 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1061 vmSymbols::string_signature(), &fd); 1062 if (found) { 1063 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1064 if (name_oop == NULL) { 1065 return NULL; 1066 } 1067 const char* name = java_lang_String::as_utf8_string(name_oop, 1068 java_runtime_version, 1069 sizeof(java_runtime_version)); 1070 return name; 1071 } else { 1072 return NULL; 1073 } 1074 } 1075 1076 // General purpose hook into Java code, run once when the VM is initialized. 1077 // The Java library method itself may be changed independently from the VM. 1078 static void call_postVMInitHook(TRAPS) { 1079 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1080 instanceKlassHandle klass (THREAD, k); 1081 if (klass.not_null()) { 1082 JavaValue result(T_VOID); 1083 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1084 vmSymbols::void_method_signature(), 1085 CHECK); 1086 } 1087 } 1088 1089 static void reset_vm_info_property(TRAPS) { 1090 // the vm info string 1091 ResourceMark rm(THREAD); 1092 const char *vm_info = VM_Version::vm_info_string(); 1093 1094 // java.lang.System class 1095 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1096 instanceKlassHandle klass (THREAD, k); 1097 1098 // setProperty arguments 1099 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1100 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1101 1102 // return value 1103 JavaValue r(T_OBJECT); 1104 1105 // public static String setProperty(String key, String value); 1106 JavaCalls::call_static(&r, 1107 klass, 1108 vmSymbols::setProperty_name(), 1109 vmSymbols::string_string_string_signature(), 1110 key_str, 1111 value_str, 1112 CHECK); 1113 } 1114 1115 1116 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, 1117 bool daemon, TRAPS) { 1118 assert(thread_group.not_null(), "thread group should be specified"); 1119 assert(threadObj() == NULL, "should only create Java thread object once"); 1120 1121 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1122 instanceKlassHandle klass (THREAD, k); 1123 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1124 1125 java_lang_Thread::set_thread(thread_oop(), this); 1126 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1127 set_threadObj(thread_oop()); 1128 1129 JavaValue result(T_VOID); 1130 if (thread_name != NULL) { 1131 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1132 // Thread gets assigned specified name and null target 1133 JavaCalls::call_special(&result, 1134 thread_oop, 1135 klass, 1136 vmSymbols::object_initializer_name(), 1137 vmSymbols::threadgroup_string_void_signature(), 1138 thread_group, // Argument 1 1139 name, // Argument 2 1140 THREAD); 1141 } else { 1142 // Thread gets assigned name "Thread-nnn" and null target 1143 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1144 JavaCalls::call_special(&result, 1145 thread_oop, 1146 klass, 1147 vmSymbols::object_initializer_name(), 1148 vmSymbols::threadgroup_runnable_void_signature(), 1149 thread_group, // Argument 1 1150 Handle(), // Argument 2 1151 THREAD); 1152 } 1153 1154 1155 if (daemon) { 1156 java_lang_Thread::set_daemon(thread_oop()); 1157 } 1158 1159 if (HAS_PENDING_EXCEPTION) { 1160 return; 1161 } 1162 1163 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1164 Handle threadObj(this, this->threadObj()); 1165 1166 JavaCalls::call_special(&result, 1167 thread_group, 1168 group, 1169 vmSymbols::add_method_name(), 1170 vmSymbols::thread_void_signature(), 1171 threadObj, // Arg 1 1172 THREAD); 1173 1174 1175 } 1176 1177 // NamedThread -- non-JavaThread subclasses with multiple 1178 // uniquely named instances should derive from this. 1179 NamedThread::NamedThread() : Thread() { 1180 _name = NULL; 1181 _processed_thread = NULL; 1182 } 1183 1184 NamedThread::~NamedThread() { 1185 if (_name != NULL) { 1186 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1187 _name = NULL; 1188 } 1189 } 1190 1191 void NamedThread::set_name(const char* format, ...) { 1192 guarantee(_name == NULL, "Only get to set name once."); 1193 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1194 guarantee(_name != NULL, "alloc failure"); 1195 va_list ap; 1196 va_start(ap, format); 1197 jio_vsnprintf(_name, max_name_len, format, ap); 1198 va_end(ap); 1199 } 1200 1201 void NamedThread::print_on(outputStream* st) const { 1202 st->print("\"%s\" ", name()); 1203 Thread::print_on(st); 1204 st->cr(); 1205 } 1206 1207 1208 // ======= WatcherThread ======== 1209 1210 // The watcher thread exists to simulate timer interrupts. It should 1211 // be replaced by an abstraction over whatever native support for 1212 // timer interrupts exists on the platform. 1213 1214 WatcherThread* WatcherThread::_watcher_thread = NULL; 1215 bool WatcherThread::_startable = false; 1216 volatile bool WatcherThread::_should_terminate = false; 1217 1218 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1219 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1220 if (os::create_thread(this, os::watcher_thread)) { 1221 _watcher_thread = this; 1222 1223 // Set the watcher thread to the highest OS priority which should not be 1224 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1225 // is created. The only normal thread using this priority is the reference 1226 // handler thread, which runs for very short intervals only. 1227 // If the VMThread's priority is not lower than the WatcherThread profiling 1228 // will be inaccurate. 1229 os::set_priority(this, MaxPriority); 1230 if (!DisableStartThread) { 1231 os::start_thread(this); 1232 } 1233 } 1234 } 1235 1236 int WatcherThread::sleep() const { 1237 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1238 1239 // remaining will be zero if there are no tasks, 1240 // causing the WatcherThread to sleep until a task is 1241 // enrolled 1242 int remaining = PeriodicTask::time_to_wait(); 1243 int time_slept = 0; 1244 1245 // we expect this to timeout - we only ever get unparked when 1246 // we should terminate or when a new task has been enrolled 1247 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1248 1249 jlong time_before_loop = os::javaTimeNanos(); 1250 1251 for (;;) { 1252 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1253 jlong now = os::javaTimeNanos(); 1254 1255 if (remaining == 0) { 1256 // if we didn't have any tasks we could have waited for a long time 1257 // consider the time_slept zero and reset time_before_loop 1258 time_slept = 0; 1259 time_before_loop = now; 1260 } else { 1261 // need to recalculate since we might have new tasks in _tasks 1262 time_slept = (int) ((now - time_before_loop) / 1000000); 1263 } 1264 1265 // Change to task list or spurious wakeup of some kind 1266 if (timedout || _should_terminate) { 1267 break; 1268 } 1269 1270 remaining = PeriodicTask::time_to_wait(); 1271 if (remaining == 0) { 1272 // Last task was just disenrolled so loop around and wait until 1273 // another task gets enrolled 1274 continue; 1275 } 1276 1277 remaining -= time_slept; 1278 if (remaining <= 0) { 1279 break; 1280 } 1281 } 1282 1283 return time_slept; 1284 } 1285 1286 void WatcherThread::run() { 1287 assert(this == watcher_thread(), "just checking"); 1288 1289 this->record_stack_base_and_size(); 1290 this->initialize_thread_local_storage(); 1291 this->set_active_handles(JNIHandleBlock::allocate_block()); 1292 while (!_should_terminate) { 1293 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1294 assert(watcher_thread() == this, "thread consistency check"); 1295 1296 // Calculate how long it'll be until the next PeriodicTask work 1297 // should be done, and sleep that amount of time. 1298 int time_waited = sleep(); 1299 1300 if (is_error_reported()) { 1301 // A fatal error has happened, the error handler(VMError::report_and_die) 1302 // should abort JVM after creating an error log file. However in some 1303 // rare cases, the error handler itself might deadlock. Here we try to 1304 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1305 // 1306 // This code is in WatcherThread because WatcherThread wakes up 1307 // periodically so the fatal error handler doesn't need to do anything; 1308 // also because the WatcherThread is less likely to crash than other 1309 // threads. 1310 1311 for (;;) { 1312 if (!ShowMessageBoxOnError 1313 && (OnError == NULL || OnError[0] == '\0') 1314 && Arguments::abort_hook() == NULL) { 1315 os::sleep(this, 2 * 60 * 1000, false); 1316 fdStream err(defaultStream::output_fd()); 1317 err.print_raw_cr("# [ timer expired, abort... ]"); 1318 // skip atexit/vm_exit/vm_abort hooks 1319 os::die(); 1320 } 1321 1322 // Wake up 5 seconds later, the fatal handler may reset OnError or 1323 // ShowMessageBoxOnError when it is ready to abort. 1324 os::sleep(this, 5 * 1000, false); 1325 } 1326 } 1327 1328 PeriodicTask::real_time_tick(time_waited); 1329 } 1330 1331 // Signal that it is terminated 1332 { 1333 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1334 _watcher_thread = NULL; 1335 Terminator_lock->notify(); 1336 } 1337 1338 // Thread destructor usually does this.. 1339 ThreadLocalStorage::set_thread(NULL); 1340 } 1341 1342 void WatcherThread::start() { 1343 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1344 1345 if (watcher_thread() == NULL && _startable) { 1346 _should_terminate = false; 1347 // Create the single instance of WatcherThread 1348 new WatcherThread(); 1349 } 1350 } 1351 1352 void WatcherThread::make_startable() { 1353 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1354 _startable = true; 1355 } 1356 1357 void WatcherThread::stop() { 1358 // Get the PeriodicTask_lock if we can. If we cannot, then the 1359 // WatcherThread is using it and we don't want to block on that lock 1360 // here because that might cause a safepoint deadlock depending on 1361 // what the current WatcherThread tasks are doing. 1362 bool have_lock = PeriodicTask_lock->try_lock(); 1363 1364 _should_terminate = true; 1365 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1366 1367 if (have_lock) { 1368 WatcherThread* watcher = watcher_thread(); 1369 if (watcher != NULL) { 1370 // If we managed to get the lock, then we should unpark the 1371 // WatcherThread so that it can see we want it to stop. 1372 watcher->unpark(); 1373 } 1374 1375 PeriodicTask_lock->unlock(); 1376 } 1377 1378 // it is ok to take late safepoints here, if needed 1379 MutexLocker mu(Terminator_lock); 1380 1381 while (watcher_thread() != NULL) { 1382 // This wait should make safepoint checks, wait without a timeout, 1383 // and wait as a suspend-equivalent condition. 1384 // 1385 // Note: If the FlatProfiler is running, then this thread is waiting 1386 // for the WatcherThread to terminate and the WatcherThread, via the 1387 // FlatProfiler task, is waiting for the external suspend request on 1388 // this thread to complete. wait_for_ext_suspend_completion() will 1389 // eventually timeout, but that takes time. Making this wait a 1390 // suspend-equivalent condition solves that timeout problem. 1391 // 1392 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1393 Mutex::_as_suspend_equivalent_flag); 1394 } 1395 } 1396 1397 void WatcherThread::unpark() { 1398 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() 1399 ? NULL 1400 : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1401 PeriodicTask_lock->notify(); 1402 } 1403 1404 void WatcherThread::print_on(outputStream* st) const { 1405 st->print("\"%s\" ", name()); 1406 Thread::print_on(st); 1407 st->cr(); 1408 } 1409 1410 // ======= JavaThread ======== 1411 1412 // A JavaThread is a normal Java thread 1413 1414 void JavaThread::initialize() { 1415 // Initialize fields 1416 1417 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1418 set_claimed_par_id(UINT_MAX); 1419 1420 set_saved_exception_pc(NULL); 1421 set_threadObj(NULL); 1422 _anchor.clear(); 1423 set_entry_point(NULL); 1424 set_jni_functions(jni_functions()); 1425 set_callee_target(NULL); 1426 set_vm_result(NULL); 1427 set_vm_result_2(NULL); 1428 set_vframe_array_head(NULL); 1429 set_vframe_array_last(NULL); 1430 set_deferred_locals(NULL); 1431 set_deopt_mark(NULL); 1432 set_deopt_nmethod(NULL); 1433 clear_must_deopt_id(); 1434 set_monitor_chunks(NULL); 1435 set_next(NULL); 1436 set_thread_state(_thread_new); 1437 _terminated = _not_terminated; 1438 _privileged_stack_top = NULL; 1439 _array_for_gc = NULL; 1440 _suspend_equivalent = false; 1441 _in_deopt_handler = 0; 1442 _doing_unsafe_access = false; 1443 _stack_guard_state = stack_guard_unused; 1444 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1445 _exception_pc = 0; 1446 _exception_handler_pc = 0; 1447 _is_method_handle_return = 0; 1448 _jvmti_thread_state= NULL; 1449 _should_post_on_exceptions_flag = JNI_FALSE; 1450 _jvmti_get_loaded_classes_closure = NULL; 1451 _interp_only_mode = 0; 1452 _special_runtime_exit_condition = _no_async_condition; 1453 _pending_async_exception = NULL; 1454 _thread_stat = NULL; 1455 _thread_stat = new ThreadStatistics(); 1456 _blocked_on_compilation = false; 1457 _jni_active_critical = 0; 1458 _pending_jni_exception_check_fn = NULL; 1459 _do_not_unlock_if_synchronized = false; 1460 _cached_monitor_info = NULL; 1461 _parker = Parker::Allocate(this); 1462 1463 #ifndef PRODUCT 1464 _jmp_ring_index = 0; 1465 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1466 record_jump(NULL, NULL, NULL, 0); 1467 } 1468 #endif // PRODUCT 1469 1470 set_thread_profiler(NULL); 1471 if (FlatProfiler::is_active()) { 1472 // This is where we would decide to either give each thread it's own profiler 1473 // or use one global one from FlatProfiler, 1474 // or up to some count of the number of profiled threads, etc. 1475 ThreadProfiler* pp = new ThreadProfiler(); 1476 pp->engage(); 1477 set_thread_profiler(pp); 1478 } 1479 1480 // Setup safepoint state info for this thread 1481 ThreadSafepointState::create(this); 1482 1483 debug_only(_java_call_counter = 0); 1484 1485 // JVMTI PopFrame support 1486 _popframe_condition = popframe_inactive; 1487 _popframe_preserved_args = NULL; 1488 _popframe_preserved_args_size = 0; 1489 1490 pd_initialize(); 1491 } 1492 1493 #if INCLUDE_ALL_GCS 1494 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1495 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1496 #endif // INCLUDE_ALL_GCS 1497 1498 JavaThread::JavaThread(bool is_attaching_via_jni) : 1499 Thread() 1500 #if INCLUDE_ALL_GCS 1501 , _satb_mark_queue(&_satb_mark_queue_set), 1502 _dirty_card_queue(&_dirty_card_queue_set) 1503 #endif // INCLUDE_ALL_GCS 1504 { 1505 initialize(); 1506 if (is_attaching_via_jni) { 1507 _jni_attach_state = _attaching_via_jni; 1508 } else { 1509 _jni_attach_state = _not_attaching_via_jni; 1510 } 1511 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1512 } 1513 1514 bool JavaThread::reguard_stack(address cur_sp) { 1515 if (_stack_guard_state != stack_guard_yellow_disabled) { 1516 return true; // Stack already guarded or guard pages not needed. 1517 } 1518 1519 if (register_stack_overflow()) { 1520 // For those architectures which have separate register and 1521 // memory stacks, we must check the register stack to see if 1522 // it has overflowed. 1523 return false; 1524 } 1525 1526 // Java code never executes within the yellow zone: the latter is only 1527 // there to provoke an exception during stack banging. If java code 1528 // is executing there, either StackShadowPages should be larger, or 1529 // some exception code in c1, c2 or the interpreter isn't unwinding 1530 // when it should. 1531 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1532 1533 enable_stack_yellow_zone(); 1534 return true; 1535 } 1536 1537 bool JavaThread::reguard_stack(void) { 1538 return reguard_stack(os::current_stack_pointer()); 1539 } 1540 1541 1542 void JavaThread::block_if_vm_exited() { 1543 if (_terminated == _vm_exited) { 1544 // _vm_exited is set at safepoint, and Threads_lock is never released 1545 // we will block here forever 1546 Threads_lock->lock_without_safepoint_check(); 1547 ShouldNotReachHere(); 1548 } 1549 } 1550 1551 1552 // Remove this ifdef when C1 is ported to the compiler interface. 1553 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1554 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1555 1556 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1557 Thread() 1558 #if INCLUDE_ALL_GCS 1559 , _satb_mark_queue(&_satb_mark_queue_set), 1560 _dirty_card_queue(&_dirty_card_queue_set) 1561 #endif // INCLUDE_ALL_GCS 1562 { 1563 if (TraceThreadEvents) { 1564 tty->print_cr("creating thread %p", this); 1565 } 1566 initialize(); 1567 _jni_attach_state = _not_attaching_via_jni; 1568 set_entry_point(entry_point); 1569 // Create the native thread itself. 1570 // %note runtime_23 1571 os::ThreadType thr_type = os::java_thread; 1572 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1573 os::java_thread; 1574 os::create_thread(this, thr_type, stack_sz); 1575 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1576 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1577 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1578 // the exception consists of creating the exception object & initializing it, initialization 1579 // will leave the VM via a JavaCall and then all locks must be unlocked). 1580 // 1581 // The thread is still suspended when we reach here. Thread must be explicit started 1582 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1583 // by calling Threads:add. The reason why this is not done here, is because the thread 1584 // object must be fully initialized (take a look at JVM_Start) 1585 } 1586 1587 JavaThread::~JavaThread() { 1588 if (TraceThreadEvents) { 1589 tty->print_cr("terminate thread %p", this); 1590 } 1591 1592 // JSR166 -- return the parker to the free list 1593 Parker::Release(_parker); 1594 _parker = NULL; 1595 1596 // Free any remaining previous UnrollBlock 1597 vframeArray* old_array = vframe_array_last(); 1598 1599 if (old_array != NULL) { 1600 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1601 old_array->set_unroll_block(NULL); 1602 delete old_info; 1603 delete old_array; 1604 } 1605 1606 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1607 if (deferred != NULL) { 1608 // This can only happen if thread is destroyed before deoptimization occurs. 1609 assert(deferred->length() != 0, "empty array!"); 1610 do { 1611 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1612 deferred->remove_at(0); 1613 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1614 delete dlv; 1615 } while (deferred->length() != 0); 1616 delete deferred; 1617 } 1618 1619 // All Java related clean up happens in exit 1620 ThreadSafepointState::destroy(this); 1621 if (_thread_profiler != NULL) delete _thread_profiler; 1622 if (_thread_stat != NULL) delete _thread_stat; 1623 } 1624 1625 1626 // The first routine called by a new Java thread 1627 void JavaThread::run() { 1628 // initialize thread-local alloc buffer related fields 1629 this->initialize_tlab(); 1630 1631 // used to test validity of stack trace backs 1632 this->record_base_of_stack_pointer(); 1633 1634 // Record real stack base and size. 1635 this->record_stack_base_and_size(); 1636 1637 // Initialize thread local storage; set before calling MutexLocker 1638 this->initialize_thread_local_storage(); 1639 1640 this->create_stack_guard_pages(); 1641 1642 this->cache_global_variables(); 1643 1644 // Thread is now sufficient initialized to be handled by the safepoint code as being 1645 // in the VM. Change thread state from _thread_new to _thread_in_vm 1646 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1647 1648 assert(JavaThread::current() == this, "sanity check"); 1649 assert(!Thread::current()->owns_locks(), "sanity check"); 1650 1651 DTRACE_THREAD_PROBE(start, this); 1652 1653 // This operation might block. We call that after all safepoint checks for a new thread has 1654 // been completed. 1655 this->set_active_handles(JNIHandleBlock::allocate_block()); 1656 1657 if (JvmtiExport::should_post_thread_life()) { 1658 JvmtiExport::post_thread_start(this); 1659 } 1660 1661 EventThreadStart event; 1662 if (event.should_commit()) { 1663 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1664 event.commit(); 1665 } 1666 1667 // We call another function to do the rest so we are sure that the stack addresses used 1668 // from there will be lower than the stack base just computed 1669 thread_main_inner(); 1670 1671 // Note, thread is no longer valid at this point! 1672 } 1673 1674 1675 void JavaThread::thread_main_inner() { 1676 assert(JavaThread::current() == this, "sanity check"); 1677 assert(this->threadObj() != NULL, "just checking"); 1678 1679 // Execute thread entry point unless this thread has a pending exception 1680 // or has been stopped before starting. 1681 // Note: Due to JVM_StopThread we can have pending exceptions already! 1682 if (!this->has_pending_exception() && 1683 !java_lang_Thread::is_stillborn(this->threadObj())) { 1684 { 1685 ResourceMark rm(this); 1686 this->set_native_thread_name(this->get_thread_name()); 1687 } 1688 HandleMark hm(this); 1689 this->entry_point()(this, this); 1690 } 1691 1692 DTRACE_THREAD_PROBE(stop, this); 1693 1694 this->exit(false); 1695 delete this; 1696 } 1697 1698 1699 static void ensure_join(JavaThread* thread) { 1700 // We do not need to grap the Threads_lock, since we are operating on ourself. 1701 Handle threadObj(thread, thread->threadObj()); 1702 assert(threadObj.not_null(), "java thread object must exist"); 1703 ObjectLocker lock(threadObj, thread); 1704 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1705 thread->clear_pending_exception(); 1706 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1707 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1708 // Clear the native thread instance - this makes isAlive return false and allows the join() 1709 // to complete once we've done the notify_all below 1710 java_lang_Thread::set_thread(threadObj(), NULL); 1711 lock.notify_all(thread); 1712 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1713 thread->clear_pending_exception(); 1714 } 1715 1716 1717 // For any new cleanup additions, please check to see if they need to be applied to 1718 // cleanup_failed_attach_current_thread as well. 1719 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1720 assert(this == JavaThread::current(), "thread consistency check"); 1721 1722 HandleMark hm(this); 1723 Handle uncaught_exception(this, this->pending_exception()); 1724 this->clear_pending_exception(); 1725 Handle threadObj(this, this->threadObj()); 1726 assert(threadObj.not_null(), "Java thread object should be created"); 1727 1728 if (get_thread_profiler() != NULL) { 1729 get_thread_profiler()->disengage(); 1730 ResourceMark rm; 1731 get_thread_profiler()->print(get_thread_name()); 1732 } 1733 1734 1735 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1736 { 1737 EXCEPTION_MARK; 1738 1739 CLEAR_PENDING_EXCEPTION; 1740 } 1741 if (!destroy_vm) { 1742 if (uncaught_exception.not_null()) { 1743 EXCEPTION_MARK; 1744 // Call method Thread.dispatchUncaughtException(). 1745 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1746 JavaValue result(T_VOID); 1747 JavaCalls::call_virtual(&result, 1748 threadObj, thread_klass, 1749 vmSymbols::dispatchUncaughtException_name(), 1750 vmSymbols::throwable_void_signature(), 1751 uncaught_exception, 1752 THREAD); 1753 if (HAS_PENDING_EXCEPTION) { 1754 ResourceMark rm(this); 1755 jio_fprintf(defaultStream::error_stream(), 1756 "\nException: %s thrown from the UncaughtExceptionHandler" 1757 " in thread \"%s\"\n", 1758 pending_exception()->klass()->external_name(), 1759 get_thread_name()); 1760 CLEAR_PENDING_EXCEPTION; 1761 } 1762 } 1763 1764 // Called before the java thread exit since we want to read info 1765 // from java_lang_Thread object 1766 EventThreadEnd event; 1767 if (event.should_commit()) { 1768 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1769 event.commit(); 1770 } 1771 1772 // Call after last event on thread 1773 EVENT_THREAD_EXIT(this); 1774 1775 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1776 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1777 // is deprecated anyhow. 1778 if (!is_Compiler_thread()) { 1779 int count = 3; 1780 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1781 EXCEPTION_MARK; 1782 JavaValue result(T_VOID); 1783 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1784 JavaCalls::call_virtual(&result, 1785 threadObj, thread_klass, 1786 vmSymbols::exit_method_name(), 1787 vmSymbols::void_method_signature(), 1788 THREAD); 1789 CLEAR_PENDING_EXCEPTION; 1790 } 1791 } 1792 // notify JVMTI 1793 if (JvmtiExport::should_post_thread_life()) { 1794 JvmtiExport::post_thread_end(this); 1795 } 1796 1797 // We have notified the agents that we are exiting, before we go on, 1798 // we must check for a pending external suspend request and honor it 1799 // in order to not surprise the thread that made the suspend request. 1800 while (true) { 1801 { 1802 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1803 if (!is_external_suspend()) { 1804 set_terminated(_thread_exiting); 1805 ThreadService::current_thread_exiting(this); 1806 break; 1807 } 1808 // Implied else: 1809 // Things get a little tricky here. We have a pending external 1810 // suspend request, but we are holding the SR_lock so we 1811 // can't just self-suspend. So we temporarily drop the lock 1812 // and then self-suspend. 1813 } 1814 1815 ThreadBlockInVM tbivm(this); 1816 java_suspend_self(); 1817 1818 // We're done with this suspend request, but we have to loop around 1819 // and check again. Eventually we will get SR_lock without a pending 1820 // external suspend request and will be able to mark ourselves as 1821 // exiting. 1822 } 1823 // no more external suspends are allowed at this point 1824 } else { 1825 // before_exit() has already posted JVMTI THREAD_END events 1826 } 1827 1828 // Notify waiters on thread object. This has to be done after exit() is called 1829 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1830 // group should have the destroyed bit set before waiters are notified). 1831 ensure_join(this); 1832 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1833 1834 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1835 // held by this thread must be released. A detach operation must only 1836 // get here if there are no Java frames on the stack. Therefore, any 1837 // owned monitors at this point MUST be JNI-acquired monitors which are 1838 // pre-inflated and in the monitor cache. 1839 // 1840 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1841 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1842 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1843 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1844 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1845 } 1846 1847 // These things needs to be done while we are still a Java Thread. Make sure that thread 1848 // is in a consistent state, in case GC happens 1849 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1850 1851 if (active_handles() != NULL) { 1852 JNIHandleBlock* block = active_handles(); 1853 set_active_handles(NULL); 1854 JNIHandleBlock::release_block(block); 1855 } 1856 1857 if (free_handle_block() != NULL) { 1858 JNIHandleBlock* block = free_handle_block(); 1859 set_free_handle_block(NULL); 1860 JNIHandleBlock::release_block(block); 1861 } 1862 1863 // These have to be removed while this is still a valid thread. 1864 remove_stack_guard_pages(); 1865 1866 if (UseTLAB) { 1867 tlab().make_parsable(true); // retire TLAB 1868 } 1869 1870 if (JvmtiEnv::environments_might_exist()) { 1871 JvmtiExport::cleanup_thread(this); 1872 } 1873 1874 // We must flush any deferred card marks before removing a thread from 1875 // the list of active threads. 1876 Universe::heap()->flush_deferred_store_barrier(this); 1877 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1878 1879 #if INCLUDE_ALL_GCS 1880 // We must flush the G1-related buffers before removing a thread 1881 // from the list of active threads. We must do this after any deferred 1882 // card marks have been flushed (above) so that any entries that are 1883 // added to the thread's dirty card queue as a result are not lost. 1884 if (UseG1GC) { 1885 flush_barrier_queues(); 1886 } 1887 #endif // INCLUDE_ALL_GCS 1888 1889 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1890 Threads::remove(this); 1891 } 1892 1893 #if INCLUDE_ALL_GCS 1894 // Flush G1-related queues. 1895 void JavaThread::flush_barrier_queues() { 1896 satb_mark_queue().flush(); 1897 dirty_card_queue().flush(); 1898 } 1899 1900 void JavaThread::initialize_queues() { 1901 assert(!SafepointSynchronize::is_at_safepoint(), 1902 "we should not be at a safepoint"); 1903 1904 ObjPtrQueue& satb_queue = satb_mark_queue(); 1905 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1906 // The SATB queue should have been constructed with its active 1907 // field set to false. 1908 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1909 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1910 // If we are creating the thread during a marking cycle, we should 1911 // set the active field of the SATB queue to true. 1912 if (satb_queue_set.is_active()) { 1913 satb_queue.set_active(true); 1914 } 1915 1916 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1917 // The dirty card queue should have been constructed with its 1918 // active field set to true. 1919 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1920 } 1921 #endif // INCLUDE_ALL_GCS 1922 1923 void JavaThread::cleanup_failed_attach_current_thread() { 1924 if (get_thread_profiler() != NULL) { 1925 get_thread_profiler()->disengage(); 1926 ResourceMark rm; 1927 get_thread_profiler()->print(get_thread_name()); 1928 } 1929 1930 if (active_handles() != NULL) { 1931 JNIHandleBlock* block = active_handles(); 1932 set_active_handles(NULL); 1933 JNIHandleBlock::release_block(block); 1934 } 1935 1936 if (free_handle_block() != NULL) { 1937 JNIHandleBlock* block = free_handle_block(); 1938 set_free_handle_block(NULL); 1939 JNIHandleBlock::release_block(block); 1940 } 1941 1942 // These have to be removed while this is still a valid thread. 1943 remove_stack_guard_pages(); 1944 1945 if (UseTLAB) { 1946 tlab().make_parsable(true); // retire TLAB, if any 1947 } 1948 1949 #if INCLUDE_ALL_GCS 1950 if (UseG1GC) { 1951 flush_barrier_queues(); 1952 } 1953 #endif // INCLUDE_ALL_GCS 1954 1955 Threads::remove(this); 1956 delete this; 1957 } 1958 1959 1960 1961 1962 JavaThread* JavaThread::active() { 1963 Thread* thread = ThreadLocalStorage::thread(); 1964 assert(thread != NULL, "just checking"); 1965 if (thread->is_Java_thread()) { 1966 return (JavaThread*) thread; 1967 } else { 1968 assert(thread->is_VM_thread(), "this must be a vm thread"); 1969 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1970 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1971 assert(ret->is_Java_thread(), "must be a Java thread"); 1972 return ret; 1973 } 1974 } 1975 1976 bool JavaThread::is_lock_owned(address adr) const { 1977 if (Thread::is_lock_owned(adr)) return true; 1978 1979 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1980 if (chunk->contains(adr)) return true; 1981 } 1982 1983 return false; 1984 } 1985 1986 1987 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1988 chunk->set_next(monitor_chunks()); 1989 set_monitor_chunks(chunk); 1990 } 1991 1992 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1993 guarantee(monitor_chunks() != NULL, "must be non empty"); 1994 if (monitor_chunks() == chunk) { 1995 set_monitor_chunks(chunk->next()); 1996 } else { 1997 MonitorChunk* prev = monitor_chunks(); 1998 while (prev->next() != chunk) prev = prev->next(); 1999 prev->set_next(chunk->next()); 2000 } 2001 } 2002 2003 // JVM support. 2004 2005 // Note: this function shouldn't block if it's called in 2006 // _thread_in_native_trans state (such as from 2007 // check_special_condition_for_native_trans()). 2008 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2009 2010 if (has_last_Java_frame() && has_async_condition()) { 2011 // If we are at a polling page safepoint (not a poll return) 2012 // then we must defer async exception because live registers 2013 // will be clobbered by the exception path. Poll return is 2014 // ok because the call we a returning from already collides 2015 // with exception handling registers and so there is no issue. 2016 // (The exception handling path kills call result registers but 2017 // this is ok since the exception kills the result anyway). 2018 2019 if (is_at_poll_safepoint()) { 2020 // if the code we are returning to has deoptimized we must defer 2021 // the exception otherwise live registers get clobbered on the 2022 // exception path before deoptimization is able to retrieve them. 2023 // 2024 RegisterMap map(this, false); 2025 frame caller_fr = last_frame().sender(&map); 2026 assert(caller_fr.is_compiled_frame(), "what?"); 2027 if (caller_fr.is_deoptimized_frame()) { 2028 if (TraceExceptions) { 2029 ResourceMark rm; 2030 tty->print_cr("deferred async exception at compiled safepoint"); 2031 } 2032 return; 2033 } 2034 } 2035 } 2036 2037 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2038 if (condition == _no_async_condition) { 2039 // Conditions have changed since has_special_runtime_exit_condition() 2040 // was called: 2041 // - if we were here only because of an external suspend request, 2042 // then that was taken care of above (or cancelled) so we are done 2043 // - if we were here because of another async request, then it has 2044 // been cleared between the has_special_runtime_exit_condition() 2045 // and now so again we are done 2046 return; 2047 } 2048 2049 // Check for pending async. exception 2050 if (_pending_async_exception != NULL) { 2051 // Only overwrite an already pending exception, if it is not a threadDeath. 2052 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2053 2054 // We cannot call Exceptions::_throw(...) here because we cannot block 2055 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2056 2057 if (TraceExceptions) { 2058 ResourceMark rm; 2059 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2060 if (has_last_Java_frame()) { 2061 frame f = last_frame(); 2062 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2063 } 2064 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2065 } 2066 _pending_async_exception = NULL; 2067 clear_has_async_exception(); 2068 } 2069 } 2070 2071 if (check_unsafe_error && 2072 condition == _async_unsafe_access_error && !has_pending_exception()) { 2073 condition = _no_async_condition; // done 2074 switch (thread_state()) { 2075 case _thread_in_vm: { 2076 JavaThread* THREAD = this; 2077 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2078 } 2079 case _thread_in_native: { 2080 ThreadInVMfromNative tiv(this); 2081 JavaThread* THREAD = this; 2082 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2083 } 2084 case _thread_in_Java: { 2085 ThreadInVMfromJava tiv(this); 2086 JavaThread* THREAD = this; 2087 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2088 } 2089 default: 2090 ShouldNotReachHere(); 2091 } 2092 } 2093 2094 assert(condition == _no_async_condition || has_pending_exception() || 2095 (!check_unsafe_error && condition == _async_unsafe_access_error), 2096 "must have handled the async condition, if no exception"); 2097 } 2098 2099 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2100 // 2101 // Check for pending external suspend. Internal suspend requests do 2102 // not use handle_special_runtime_exit_condition(). 2103 // If JNIEnv proxies are allowed, don't self-suspend if the target 2104 // thread is not the current thread. In older versions of jdbx, jdbx 2105 // threads could call into the VM with another thread's JNIEnv so we 2106 // can be here operating on behalf of a suspended thread (4432884). 2107 bool do_self_suspend = is_external_suspend_with_lock(); 2108 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2109 // 2110 // Because thread is external suspended the safepoint code will count 2111 // thread as at a safepoint. This can be odd because we can be here 2112 // as _thread_in_Java which would normally transition to _thread_blocked 2113 // at a safepoint. We would like to mark the thread as _thread_blocked 2114 // before calling java_suspend_self like all other callers of it but 2115 // we must then observe proper safepoint protocol. (We can't leave 2116 // _thread_blocked with a safepoint in progress). However we can be 2117 // here as _thread_in_native_trans so we can't use a normal transition 2118 // constructor/destructor pair because they assert on that type of 2119 // transition. We could do something like: 2120 // 2121 // JavaThreadState state = thread_state(); 2122 // set_thread_state(_thread_in_vm); 2123 // { 2124 // ThreadBlockInVM tbivm(this); 2125 // java_suspend_self() 2126 // } 2127 // set_thread_state(_thread_in_vm_trans); 2128 // if (safepoint) block; 2129 // set_thread_state(state); 2130 // 2131 // but that is pretty messy. Instead we just go with the way the 2132 // code has worked before and note that this is the only path to 2133 // java_suspend_self that doesn't put the thread in _thread_blocked 2134 // mode. 2135 2136 frame_anchor()->make_walkable(this); 2137 java_suspend_self(); 2138 2139 // We might be here for reasons in addition to the self-suspend request 2140 // so check for other async requests. 2141 } 2142 2143 if (check_asyncs) { 2144 check_and_handle_async_exceptions(); 2145 } 2146 } 2147 2148 void JavaThread::send_thread_stop(oop java_throwable) { 2149 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2150 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2151 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2152 2153 // Do not throw asynchronous exceptions against the compiler thread 2154 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2155 if (is_Compiler_thread()) return; 2156 2157 { 2158 // Actually throw the Throwable against the target Thread - however 2159 // only if there is no thread death exception installed already. 2160 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2161 // If the topmost frame is a runtime stub, then we are calling into 2162 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2163 // must deoptimize the caller before continuing, as the compiled exception handler table 2164 // may not be valid 2165 if (has_last_Java_frame()) { 2166 frame f = last_frame(); 2167 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2168 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2169 RegisterMap reg_map(this, UseBiasedLocking); 2170 frame compiled_frame = f.sender(®_map); 2171 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2172 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2173 } 2174 } 2175 } 2176 2177 // Set async. pending exception in thread. 2178 set_pending_async_exception(java_throwable); 2179 2180 if (TraceExceptions) { 2181 ResourceMark rm; 2182 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2183 } 2184 // for AbortVMOnException flag 2185 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2186 } 2187 } 2188 2189 2190 // Interrupt thread so it will wake up from a potential wait() 2191 Thread::interrupt(this); 2192 } 2193 2194 // External suspension mechanism. 2195 // 2196 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2197 // to any VM_locks and it is at a transition 2198 // Self-suspension will happen on the transition out of the vm. 2199 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2200 // 2201 // Guarantees on return: 2202 // + Target thread will not execute any new bytecode (that's why we need to 2203 // force a safepoint) 2204 // + Target thread will not enter any new monitors 2205 // 2206 void JavaThread::java_suspend() { 2207 { MutexLocker mu(Threads_lock); 2208 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2209 return; 2210 } 2211 } 2212 2213 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2214 if (!is_external_suspend()) { 2215 // a racing resume has cancelled us; bail out now 2216 return; 2217 } 2218 2219 // suspend is done 2220 uint32_t debug_bits = 0; 2221 // Warning: is_ext_suspend_completed() may temporarily drop the 2222 // SR_lock to allow the thread to reach a stable thread state if 2223 // it is currently in a transient thread state. 2224 if (is_ext_suspend_completed(false /* !called_by_wait */, 2225 SuspendRetryDelay, &debug_bits)) { 2226 return; 2227 } 2228 } 2229 2230 VM_ForceSafepoint vm_suspend; 2231 VMThread::execute(&vm_suspend); 2232 } 2233 2234 // Part II of external suspension. 2235 // A JavaThread self suspends when it detects a pending external suspend 2236 // request. This is usually on transitions. It is also done in places 2237 // where continuing to the next transition would surprise the caller, 2238 // e.g., monitor entry. 2239 // 2240 // Returns the number of times that the thread self-suspended. 2241 // 2242 // Note: DO NOT call java_suspend_self() when you just want to block current 2243 // thread. java_suspend_self() is the second stage of cooperative 2244 // suspension for external suspend requests and should only be used 2245 // to complete an external suspend request. 2246 // 2247 int JavaThread::java_suspend_self() { 2248 int ret = 0; 2249 2250 // we are in the process of exiting so don't suspend 2251 if (is_exiting()) { 2252 clear_external_suspend(); 2253 return ret; 2254 } 2255 2256 assert(_anchor.walkable() || 2257 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2258 "must have walkable stack"); 2259 2260 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2261 2262 assert(!this->is_ext_suspended(), 2263 "a thread trying to self-suspend should not already be suspended"); 2264 2265 if (this->is_suspend_equivalent()) { 2266 // If we are self-suspending as a result of the lifting of a 2267 // suspend equivalent condition, then the suspend_equivalent 2268 // flag is not cleared until we set the ext_suspended flag so 2269 // that wait_for_ext_suspend_completion() returns consistent 2270 // results. 2271 this->clear_suspend_equivalent(); 2272 } 2273 2274 // A racing resume may have cancelled us before we grabbed SR_lock 2275 // above. Or another external suspend request could be waiting for us 2276 // by the time we return from SR_lock()->wait(). The thread 2277 // that requested the suspension may already be trying to walk our 2278 // stack and if we return now, we can change the stack out from under 2279 // it. This would be a "bad thing (TM)" and cause the stack walker 2280 // to crash. We stay self-suspended until there are no more pending 2281 // external suspend requests. 2282 while (is_external_suspend()) { 2283 ret++; 2284 this->set_ext_suspended(); 2285 2286 // _ext_suspended flag is cleared by java_resume() 2287 while (is_ext_suspended()) { 2288 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2289 } 2290 } 2291 2292 return ret; 2293 } 2294 2295 #ifdef ASSERT 2296 // verify the JavaThread has not yet been published in the Threads::list, and 2297 // hence doesn't need protection from concurrent access at this stage 2298 void JavaThread::verify_not_published() { 2299 if (!Threads_lock->owned_by_self()) { 2300 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2301 assert(!Threads::includes(this), 2302 "java thread shouldn't have been published yet!"); 2303 } else { 2304 assert(!Threads::includes(this), 2305 "java thread shouldn't have been published yet!"); 2306 } 2307 } 2308 #endif 2309 2310 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2311 // progress or when _suspend_flags is non-zero. 2312 // Current thread needs to self-suspend if there is a suspend request and/or 2313 // block if a safepoint is in progress. 2314 // Async exception ISN'T checked. 2315 // Note only the ThreadInVMfromNative transition can call this function 2316 // directly and when thread state is _thread_in_native_trans 2317 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2318 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2319 2320 JavaThread *curJT = JavaThread::current(); 2321 bool do_self_suspend = thread->is_external_suspend(); 2322 2323 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2324 2325 // If JNIEnv proxies are allowed, don't self-suspend if the target 2326 // thread is not the current thread. In older versions of jdbx, jdbx 2327 // threads could call into the VM with another thread's JNIEnv so we 2328 // can be here operating on behalf of a suspended thread (4432884). 2329 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2330 JavaThreadState state = thread->thread_state(); 2331 2332 // We mark this thread_blocked state as a suspend-equivalent so 2333 // that a caller to is_ext_suspend_completed() won't be confused. 2334 // The suspend-equivalent state is cleared by java_suspend_self(). 2335 thread->set_suspend_equivalent(); 2336 2337 // If the safepoint code sees the _thread_in_native_trans state, it will 2338 // wait until the thread changes to other thread state. There is no 2339 // guarantee on how soon we can obtain the SR_lock and complete the 2340 // self-suspend request. It would be a bad idea to let safepoint wait for 2341 // too long. Temporarily change the state to _thread_blocked to 2342 // let the VM thread know that this thread is ready for GC. The problem 2343 // of changing thread state is that safepoint could happen just after 2344 // java_suspend_self() returns after being resumed, and VM thread will 2345 // see the _thread_blocked state. We must check for safepoint 2346 // after restoring the state and make sure we won't leave while a safepoint 2347 // is in progress. 2348 thread->set_thread_state(_thread_blocked); 2349 thread->java_suspend_self(); 2350 thread->set_thread_state(state); 2351 // Make sure new state is seen by VM thread 2352 if (os::is_MP()) { 2353 if (UseMembar) { 2354 // Force a fence between the write above and read below 2355 OrderAccess::fence(); 2356 } else { 2357 // Must use this rather than serialization page in particular on Windows 2358 InterfaceSupport::serialize_memory(thread); 2359 } 2360 } 2361 } 2362 2363 if (SafepointSynchronize::do_call_back()) { 2364 // If we are safepointing, then block the caller which may not be 2365 // the same as the target thread (see above). 2366 SafepointSynchronize::block(curJT); 2367 } 2368 2369 if (thread->is_deopt_suspend()) { 2370 thread->clear_deopt_suspend(); 2371 RegisterMap map(thread, false); 2372 frame f = thread->last_frame(); 2373 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2374 f = f.sender(&map); 2375 } 2376 if (f.id() == thread->must_deopt_id()) { 2377 thread->clear_must_deopt_id(); 2378 f.deoptimize(thread); 2379 } else { 2380 fatal("missed deoptimization!"); 2381 } 2382 } 2383 } 2384 2385 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2386 // progress or when _suspend_flags is non-zero. 2387 // Current thread needs to self-suspend if there is a suspend request and/or 2388 // block if a safepoint is in progress. 2389 // Also check for pending async exception (not including unsafe access error). 2390 // Note only the native==>VM/Java barriers can call this function and when 2391 // thread state is _thread_in_native_trans. 2392 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2393 check_safepoint_and_suspend_for_native_trans(thread); 2394 2395 if (thread->has_async_exception()) { 2396 // We are in _thread_in_native_trans state, don't handle unsafe 2397 // access error since that may block. 2398 thread->check_and_handle_async_exceptions(false); 2399 } 2400 } 2401 2402 // This is a variant of the normal 2403 // check_special_condition_for_native_trans with slightly different 2404 // semantics for use by critical native wrappers. It does all the 2405 // normal checks but also performs the transition back into 2406 // thread_in_Java state. This is required so that critical natives 2407 // can potentially block and perform a GC if they are the last thread 2408 // exiting the GC_locker. 2409 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2410 check_special_condition_for_native_trans(thread); 2411 2412 // Finish the transition 2413 thread->set_thread_state(_thread_in_Java); 2414 2415 if (thread->do_critical_native_unlock()) { 2416 ThreadInVMfromJavaNoAsyncException tiv(thread); 2417 GC_locker::unlock_critical(thread); 2418 thread->clear_critical_native_unlock(); 2419 } 2420 } 2421 2422 // We need to guarantee the Threads_lock here, since resumes are not 2423 // allowed during safepoint synchronization 2424 // Can only resume from an external suspension 2425 void JavaThread::java_resume() { 2426 assert_locked_or_safepoint(Threads_lock); 2427 2428 // Sanity check: thread is gone, has started exiting or the thread 2429 // was not externally suspended. 2430 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2431 return; 2432 } 2433 2434 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2435 2436 clear_external_suspend(); 2437 2438 if (is_ext_suspended()) { 2439 clear_ext_suspended(); 2440 SR_lock()->notify_all(); 2441 } 2442 } 2443 2444 void JavaThread::create_stack_guard_pages() { 2445 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2446 address low_addr = stack_base() - stack_size(); 2447 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2448 2449 int allocate = os::allocate_stack_guard_pages(); 2450 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2451 2452 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2453 warning("Attempt to allocate stack guard pages failed."); 2454 return; 2455 } 2456 2457 if (os::guard_memory((char *) low_addr, len)) { 2458 _stack_guard_state = stack_guard_enabled; 2459 } else { 2460 warning("Attempt to protect stack guard pages failed."); 2461 if (os::uncommit_memory((char *) low_addr, len)) { 2462 warning("Attempt to deallocate stack guard pages failed."); 2463 } 2464 } 2465 } 2466 2467 void JavaThread::remove_stack_guard_pages() { 2468 assert(Thread::current() == this, "from different thread"); 2469 if (_stack_guard_state == stack_guard_unused) return; 2470 address low_addr = stack_base() - stack_size(); 2471 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2472 2473 if (os::allocate_stack_guard_pages()) { 2474 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2475 _stack_guard_state = stack_guard_unused; 2476 } else { 2477 warning("Attempt to deallocate stack guard pages failed."); 2478 } 2479 } else { 2480 if (_stack_guard_state == stack_guard_unused) return; 2481 if (os::unguard_memory((char *) low_addr, len)) { 2482 _stack_guard_state = stack_guard_unused; 2483 } else { 2484 warning("Attempt to unprotect stack guard pages failed."); 2485 } 2486 } 2487 } 2488 2489 void JavaThread::enable_stack_yellow_zone() { 2490 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2491 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2492 2493 // The base notation is from the stacks point of view, growing downward. 2494 // We need to adjust it to work correctly with guard_memory() 2495 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2496 2497 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2498 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2499 2500 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2501 _stack_guard_state = stack_guard_enabled; 2502 } else { 2503 warning("Attempt to guard stack yellow zone failed."); 2504 } 2505 enable_register_stack_guard(); 2506 } 2507 2508 void JavaThread::disable_stack_yellow_zone() { 2509 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2510 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2511 2512 // Simply return if called for a thread that does not use guard pages. 2513 if (_stack_guard_state == stack_guard_unused) return; 2514 2515 // The base notation is from the stacks point of view, growing downward. 2516 // We need to adjust it to work correctly with guard_memory() 2517 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2518 2519 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2520 _stack_guard_state = stack_guard_yellow_disabled; 2521 } else { 2522 warning("Attempt to unguard stack yellow zone failed."); 2523 } 2524 disable_register_stack_guard(); 2525 } 2526 2527 void JavaThread::enable_stack_red_zone() { 2528 // The base notation is from the stacks point of view, growing downward. 2529 // We need to adjust it to work correctly with guard_memory() 2530 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2531 address base = stack_red_zone_base() - stack_red_zone_size(); 2532 2533 guarantee(base < stack_base(), "Error calculating stack red zone"); 2534 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2535 2536 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2537 warning("Attempt to guard stack red zone failed."); 2538 } 2539 } 2540 2541 void JavaThread::disable_stack_red_zone() { 2542 // The base notation is from the stacks point of view, growing downward. 2543 // We need to adjust it to work correctly with guard_memory() 2544 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2545 address base = stack_red_zone_base() - stack_red_zone_size(); 2546 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2547 warning("Attempt to unguard stack red zone failed."); 2548 } 2549 } 2550 2551 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2552 // ignore is there is no stack 2553 if (!has_last_Java_frame()) return; 2554 // traverse the stack frames. Starts from top frame. 2555 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2556 frame* fr = fst.current(); 2557 f(fr, fst.register_map()); 2558 } 2559 } 2560 2561 2562 #ifndef PRODUCT 2563 // Deoptimization 2564 // Function for testing deoptimization 2565 void JavaThread::deoptimize() { 2566 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2567 StackFrameStream fst(this, UseBiasedLocking); 2568 bool deopt = false; // Dump stack only if a deopt actually happens. 2569 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2570 // Iterate over all frames in the thread and deoptimize 2571 for (; !fst.is_done(); fst.next()) { 2572 if (fst.current()->can_be_deoptimized()) { 2573 2574 if (only_at) { 2575 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2576 // consists of comma or carriage return separated numbers so 2577 // search for the current bci in that string. 2578 address pc = fst.current()->pc(); 2579 nmethod* nm = (nmethod*) fst.current()->cb(); 2580 ScopeDesc* sd = nm->scope_desc_at(pc); 2581 char buffer[8]; 2582 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2583 size_t len = strlen(buffer); 2584 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2585 while (found != NULL) { 2586 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2587 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2588 // Check that the bci found is bracketed by terminators. 2589 break; 2590 } 2591 found = strstr(found + 1, buffer); 2592 } 2593 if (!found) { 2594 continue; 2595 } 2596 } 2597 2598 if (DebugDeoptimization && !deopt) { 2599 deopt = true; // One-time only print before deopt 2600 tty->print_cr("[BEFORE Deoptimization]"); 2601 trace_frames(); 2602 trace_stack(); 2603 } 2604 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2605 } 2606 } 2607 2608 if (DebugDeoptimization && deopt) { 2609 tty->print_cr("[AFTER Deoptimization]"); 2610 trace_frames(); 2611 } 2612 } 2613 2614 2615 // Make zombies 2616 void JavaThread::make_zombies() { 2617 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2618 if (fst.current()->can_be_deoptimized()) { 2619 // it is a Java nmethod 2620 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2621 nm->make_not_entrant(); 2622 } 2623 } 2624 } 2625 #endif // PRODUCT 2626 2627 2628 void JavaThread::deoptimized_wrt_marked_nmethods() { 2629 if (!has_last_Java_frame()) return; 2630 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2631 StackFrameStream fst(this, UseBiasedLocking); 2632 for (; !fst.is_done(); fst.next()) { 2633 if (fst.current()->should_be_deoptimized()) { 2634 if (LogCompilation && xtty != NULL) { 2635 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2636 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2637 this->name(), nm != NULL ? nm->compile_id() : -1); 2638 } 2639 2640 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2641 } 2642 } 2643 } 2644 2645 2646 // If the caller is a NamedThread, then remember, in the current scope, 2647 // the given JavaThread in its _processed_thread field. 2648 class RememberProcessedThread: public StackObj { 2649 NamedThread* _cur_thr; 2650 public: 2651 RememberProcessedThread(JavaThread* jthr) { 2652 Thread* thread = Thread::current(); 2653 if (thread->is_Named_thread()) { 2654 _cur_thr = (NamedThread *)thread; 2655 _cur_thr->set_processed_thread(jthr); 2656 } else { 2657 _cur_thr = NULL; 2658 } 2659 } 2660 2661 ~RememberProcessedThread() { 2662 if (_cur_thr) { 2663 _cur_thr->set_processed_thread(NULL); 2664 } 2665 } 2666 }; 2667 2668 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2669 // Verify that the deferred card marks have been flushed. 2670 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2671 2672 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2673 // since there may be more than one thread using each ThreadProfiler. 2674 2675 // Traverse the GCHandles 2676 Thread::oops_do(f, cld_f, cf); 2677 2678 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2679 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2680 2681 if (has_last_Java_frame()) { 2682 // Record JavaThread to GC thread 2683 RememberProcessedThread rpt(this); 2684 2685 // Traverse the privileged stack 2686 if (_privileged_stack_top != NULL) { 2687 _privileged_stack_top->oops_do(f); 2688 } 2689 2690 // traverse the registered growable array 2691 if (_array_for_gc != NULL) { 2692 for (int index = 0; index < _array_for_gc->length(); index++) { 2693 f->do_oop(_array_for_gc->adr_at(index)); 2694 } 2695 } 2696 2697 // Traverse the monitor chunks 2698 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2699 chunk->oops_do(f); 2700 } 2701 2702 // Traverse the execution stack 2703 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2704 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2705 } 2706 } 2707 2708 // callee_target is never live across a gc point so NULL it here should 2709 // it still contain a methdOop. 2710 2711 set_callee_target(NULL); 2712 2713 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2714 // If we have deferred set_locals there might be oops waiting to be 2715 // written 2716 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2717 if (list != NULL) { 2718 for (int i = 0; i < list->length(); i++) { 2719 list->at(i)->oops_do(f); 2720 } 2721 } 2722 2723 // Traverse instance variables at the end since the GC may be moving things 2724 // around using this function 2725 f->do_oop((oop*) &_threadObj); 2726 f->do_oop((oop*) &_vm_result); 2727 f->do_oop((oop*) &_exception_oop); 2728 f->do_oop((oop*) &_pending_async_exception); 2729 2730 if (jvmti_thread_state() != NULL) { 2731 jvmti_thread_state()->oops_do(f); 2732 } 2733 } 2734 2735 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2736 Thread::nmethods_do(cf); // (super method is a no-op) 2737 2738 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2739 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2740 2741 if (has_last_Java_frame()) { 2742 // Traverse the execution stack 2743 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2744 fst.current()->nmethods_do(cf); 2745 } 2746 } 2747 } 2748 2749 void JavaThread::metadata_do(void f(Metadata*)) { 2750 Thread::metadata_do(f); 2751 if (has_last_Java_frame()) { 2752 // Traverse the execution stack to call f() on the methods in the stack 2753 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2754 fst.current()->metadata_do(f); 2755 } 2756 } else if (is_Compiler_thread()) { 2757 // need to walk ciMetadata in current compile tasks to keep alive. 2758 CompilerThread* ct = (CompilerThread*)this; 2759 if (ct->env() != NULL) { 2760 ct->env()->metadata_do(f); 2761 } 2762 } 2763 } 2764 2765 // Printing 2766 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2767 switch (_thread_state) { 2768 case _thread_uninitialized: return "_thread_uninitialized"; 2769 case _thread_new: return "_thread_new"; 2770 case _thread_new_trans: return "_thread_new_trans"; 2771 case _thread_in_native: return "_thread_in_native"; 2772 case _thread_in_native_trans: return "_thread_in_native_trans"; 2773 case _thread_in_vm: return "_thread_in_vm"; 2774 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2775 case _thread_in_Java: return "_thread_in_Java"; 2776 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2777 case _thread_blocked: return "_thread_blocked"; 2778 case _thread_blocked_trans: return "_thread_blocked_trans"; 2779 default: return "unknown thread state"; 2780 } 2781 } 2782 2783 #ifndef PRODUCT 2784 void JavaThread::print_thread_state_on(outputStream *st) const { 2785 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2786 }; 2787 void JavaThread::print_thread_state() const { 2788 print_thread_state_on(tty); 2789 } 2790 #endif // PRODUCT 2791 2792 // Called by Threads::print() for VM_PrintThreads operation 2793 void JavaThread::print_on(outputStream *st) const { 2794 st->print("\"%s\" ", get_thread_name()); 2795 oop thread_oop = threadObj(); 2796 if (thread_oop != NULL) { 2797 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2798 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2799 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2800 } 2801 Thread::print_on(st); 2802 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2803 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2804 if (thread_oop != NULL) { 2805 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2806 } 2807 #ifndef PRODUCT 2808 print_thread_state_on(st); 2809 _safepoint_state->print_on(st); 2810 #endif // PRODUCT 2811 } 2812 2813 // Called by fatal error handler. The difference between this and 2814 // JavaThread::print() is that we can't grab lock or allocate memory. 2815 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2816 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2817 oop thread_obj = threadObj(); 2818 if (thread_obj != NULL) { 2819 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2820 } 2821 st->print(" ["); 2822 st->print("%s", _get_thread_state_name(_thread_state)); 2823 if (osthread()) { 2824 st->print(", id=%d", osthread()->thread_id()); 2825 } 2826 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2827 _stack_base - _stack_size, _stack_base); 2828 st->print("]"); 2829 return; 2830 } 2831 2832 // Verification 2833 2834 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2835 2836 void JavaThread::verify() { 2837 // Verify oops in the thread. 2838 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2839 2840 // Verify the stack frames. 2841 frames_do(frame_verify); 2842 } 2843 2844 // CR 6300358 (sub-CR 2137150) 2845 // Most callers of this method assume that it can't return NULL but a 2846 // thread may not have a name whilst it is in the process of attaching to 2847 // the VM - see CR 6412693, and there are places where a JavaThread can be 2848 // seen prior to having it's threadObj set (eg JNI attaching threads and 2849 // if vm exit occurs during initialization). These cases can all be accounted 2850 // for such that this method never returns NULL. 2851 const char* JavaThread::get_thread_name() const { 2852 #ifdef ASSERT 2853 // early safepoints can hit while current thread does not yet have TLS 2854 if (!SafepointSynchronize::is_at_safepoint()) { 2855 Thread *cur = Thread::current(); 2856 if (!(cur->is_Java_thread() && cur == this)) { 2857 // Current JavaThreads are allowed to get their own name without 2858 // the Threads_lock. 2859 assert_locked_or_safepoint(Threads_lock); 2860 } 2861 } 2862 #endif // ASSERT 2863 return get_thread_name_string(); 2864 } 2865 2866 // Returns a non-NULL representation of this thread's name, or a suitable 2867 // descriptive string if there is no set name 2868 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2869 const char* name_str; 2870 oop thread_obj = threadObj(); 2871 if (thread_obj != NULL) { 2872 typeArrayOop name = java_lang_Thread::name(thread_obj); 2873 if (name != NULL) { 2874 if (buf == NULL) { 2875 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), 2876 name->length()); 2877 } else { 2878 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), 2879 name->length(), buf, buflen); 2880 } 2881 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2882 name_str = "<no-name - thread is attaching>"; 2883 } else { 2884 name_str = Thread::name(); 2885 } 2886 } else { 2887 name_str = Thread::name(); 2888 } 2889 assert(name_str != NULL, "unexpected NULL thread name"); 2890 return name_str; 2891 } 2892 2893 2894 const char* JavaThread::get_threadgroup_name() const { 2895 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2896 oop thread_obj = threadObj(); 2897 if (thread_obj != NULL) { 2898 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2899 if (thread_group != NULL) { 2900 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2901 // ThreadGroup.name can be null 2902 if (name != NULL) { 2903 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2904 return str; 2905 } 2906 } 2907 } 2908 return NULL; 2909 } 2910 2911 const char* JavaThread::get_parent_name() const { 2912 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2913 oop thread_obj = threadObj(); 2914 if (thread_obj != NULL) { 2915 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2916 if (thread_group != NULL) { 2917 oop parent = java_lang_ThreadGroup::parent(thread_group); 2918 if (parent != NULL) { 2919 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2920 // ThreadGroup.name can be null 2921 if (name != NULL) { 2922 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2923 return str; 2924 } 2925 } 2926 } 2927 } 2928 return NULL; 2929 } 2930 2931 ThreadPriority JavaThread::java_priority() const { 2932 oop thr_oop = threadObj(); 2933 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2934 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2935 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2936 return priority; 2937 } 2938 2939 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2940 2941 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2942 // Link Java Thread object <-> C++ Thread 2943 2944 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2945 // and put it into a new Handle. The Handle "thread_oop" can then 2946 // be used to pass the C++ thread object to other methods. 2947 2948 // Set the Java level thread object (jthread) field of the 2949 // new thread (a JavaThread *) to C++ thread object using the 2950 // "thread_oop" handle. 2951 2952 // Set the thread field (a JavaThread *) of the 2953 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2954 2955 Handle thread_oop(Thread::current(), 2956 JNIHandles::resolve_non_null(jni_thread)); 2957 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 2958 "must be initialized"); 2959 set_threadObj(thread_oop()); 2960 java_lang_Thread::set_thread(thread_oop(), this); 2961 2962 if (prio == NoPriority) { 2963 prio = java_lang_Thread::priority(thread_oop()); 2964 assert(prio != NoPriority, "A valid priority should be present"); 2965 } 2966 2967 // Push the Java priority down to the native thread; needs Threads_lock 2968 Thread::set_priority(this, prio); 2969 2970 prepare_ext(); 2971 2972 // Add the new thread to the Threads list and set it in motion. 2973 // We must have threads lock in order to call Threads::add. 2974 // It is crucial that we do not block before the thread is 2975 // added to the Threads list for if a GC happens, then the java_thread oop 2976 // will not be visited by GC. 2977 Threads::add(this); 2978 } 2979 2980 oop JavaThread::current_park_blocker() { 2981 // Support for JSR-166 locks 2982 oop thread_oop = threadObj(); 2983 if (thread_oop != NULL && 2984 JDK_Version::current().supports_thread_park_blocker()) { 2985 return java_lang_Thread::park_blocker(thread_oop); 2986 } 2987 return NULL; 2988 } 2989 2990 2991 void JavaThread::print_stack_on(outputStream* st) { 2992 if (!has_last_Java_frame()) return; 2993 ResourceMark rm; 2994 HandleMark hm; 2995 2996 RegisterMap reg_map(this); 2997 vframe* start_vf = last_java_vframe(®_map); 2998 int count = 0; 2999 for (vframe* f = start_vf; f; f = f->sender()) { 3000 if (f->is_java_frame()) { 3001 javaVFrame* jvf = javaVFrame::cast(f); 3002 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3003 3004 // Print out lock information 3005 if (JavaMonitorsInStackTrace) { 3006 jvf->print_lock_info_on(st, count); 3007 } 3008 } else { 3009 // Ignore non-Java frames 3010 } 3011 3012 // Bail-out case for too deep stacks 3013 count++; 3014 if (MaxJavaStackTraceDepth == count) return; 3015 } 3016 } 3017 3018 3019 // JVMTI PopFrame support 3020 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3021 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3022 if (in_bytes(size_in_bytes) != 0) { 3023 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3024 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3025 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3026 } 3027 } 3028 3029 void* JavaThread::popframe_preserved_args() { 3030 return _popframe_preserved_args; 3031 } 3032 3033 ByteSize JavaThread::popframe_preserved_args_size() { 3034 return in_ByteSize(_popframe_preserved_args_size); 3035 } 3036 3037 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3038 int sz = in_bytes(popframe_preserved_args_size()); 3039 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3040 return in_WordSize(sz / wordSize); 3041 } 3042 3043 void JavaThread::popframe_free_preserved_args() { 3044 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3045 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3046 _popframe_preserved_args = NULL; 3047 _popframe_preserved_args_size = 0; 3048 } 3049 3050 #ifndef PRODUCT 3051 3052 void JavaThread::trace_frames() { 3053 tty->print_cr("[Describe stack]"); 3054 int frame_no = 1; 3055 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3056 tty->print(" %d. ", frame_no++); 3057 fst.current()->print_value_on(tty, this); 3058 tty->cr(); 3059 } 3060 } 3061 3062 class PrintAndVerifyOopClosure: public OopClosure { 3063 protected: 3064 template <class T> inline void do_oop_work(T* p) { 3065 oop obj = oopDesc::load_decode_heap_oop(p); 3066 if (obj == NULL) return; 3067 tty->print(INTPTR_FORMAT ": ", p); 3068 if (obj->is_oop_or_null()) { 3069 if (obj->is_objArray()) { 3070 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3071 } else { 3072 obj->print(); 3073 } 3074 } else { 3075 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3076 } 3077 tty->cr(); 3078 } 3079 public: 3080 virtual void do_oop(oop* p) { do_oop_work(p); } 3081 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3082 }; 3083 3084 3085 static void oops_print(frame* f, const RegisterMap *map) { 3086 PrintAndVerifyOopClosure print; 3087 f->print_value(); 3088 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3089 } 3090 3091 // Print our all the locations that contain oops and whether they are 3092 // valid or not. This useful when trying to find the oldest frame 3093 // where an oop has gone bad since the frame walk is from youngest to 3094 // oldest. 3095 void JavaThread::trace_oops() { 3096 tty->print_cr("[Trace oops]"); 3097 frames_do(oops_print); 3098 } 3099 3100 3101 #ifdef ASSERT 3102 // Print or validate the layout of stack frames 3103 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3104 ResourceMark rm; 3105 PRESERVE_EXCEPTION_MARK; 3106 FrameValues values; 3107 int frame_no = 0; 3108 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3109 fst.current()->describe(values, ++frame_no); 3110 if (depth == frame_no) break; 3111 } 3112 if (validate_only) { 3113 values.validate(); 3114 } else { 3115 tty->print_cr("[Describe stack layout]"); 3116 values.print(this); 3117 } 3118 } 3119 #endif 3120 3121 void JavaThread::trace_stack_from(vframe* start_vf) { 3122 ResourceMark rm; 3123 int vframe_no = 1; 3124 for (vframe* f = start_vf; f; f = f->sender()) { 3125 if (f->is_java_frame()) { 3126 javaVFrame::cast(f)->print_activation(vframe_no++); 3127 } else { 3128 f->print(); 3129 } 3130 if (vframe_no > StackPrintLimit) { 3131 tty->print_cr("...<more frames>..."); 3132 return; 3133 } 3134 } 3135 } 3136 3137 3138 void JavaThread::trace_stack() { 3139 if (!has_last_Java_frame()) return; 3140 ResourceMark rm; 3141 HandleMark hm; 3142 RegisterMap reg_map(this); 3143 trace_stack_from(last_java_vframe(®_map)); 3144 } 3145 3146 3147 #endif // PRODUCT 3148 3149 3150 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3151 assert(reg_map != NULL, "a map must be given"); 3152 frame f = last_frame(); 3153 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3154 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3155 } 3156 return NULL; 3157 } 3158 3159 3160 Klass* JavaThread::security_get_caller_class(int depth) { 3161 vframeStream vfst(this); 3162 vfst.security_get_caller_frame(depth); 3163 if (!vfst.at_end()) { 3164 return vfst.method()->method_holder(); 3165 } 3166 return NULL; 3167 } 3168 3169 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3170 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3171 CompileBroker::compiler_thread_loop(); 3172 } 3173 3174 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3175 NMethodSweeper::sweeper_loop(); 3176 } 3177 3178 // Create a CompilerThread 3179 CompilerThread::CompilerThread(CompileQueue* queue, 3180 CompilerCounters* counters) 3181 : JavaThread(&compiler_thread_entry) { 3182 _env = NULL; 3183 _log = NULL; 3184 _task = NULL; 3185 _queue = queue; 3186 _counters = counters; 3187 _buffer_blob = NULL; 3188 _compiler = NULL; 3189 3190 #ifndef PRODUCT 3191 _ideal_graph_printer = NULL; 3192 #endif 3193 } 3194 3195 // Create sweeper thread 3196 CodeCacheSweeperThread::CodeCacheSweeperThread() 3197 : JavaThread(&sweeper_thread_entry) { 3198 _scanned_nmethod = NULL; 3199 } 3200 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3201 JavaThread::oops_do(f, cld_f, cf); 3202 if (_scanned_nmethod != NULL && cf != NULL) { 3203 // Safepoints can occur when the sweeper is scanning an nmethod so 3204 // process it here to make sure it isn't unloaded in the middle of 3205 // a scan. 3206 cf->do_code_blob(_scanned_nmethod); 3207 } 3208 } 3209 3210 3211 // ======= Threads ======== 3212 3213 // The Threads class links together all active threads, and provides 3214 // operations over all threads. It is protected by its own Mutex 3215 // lock, which is also used in other contexts to protect thread 3216 // operations from having the thread being operated on from exiting 3217 // and going away unexpectedly (e.g., safepoint synchronization) 3218 3219 JavaThread* Threads::_thread_list = NULL; 3220 int Threads::_number_of_threads = 0; 3221 int Threads::_number_of_non_daemon_threads = 0; 3222 int Threads::_return_code = 0; 3223 size_t JavaThread::_stack_size_at_create = 0; 3224 #ifdef ASSERT 3225 bool Threads::_vm_complete = false; 3226 #endif 3227 3228 // All JavaThreads 3229 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3230 3231 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3232 void Threads::threads_do(ThreadClosure* tc) { 3233 assert_locked_or_safepoint(Threads_lock); 3234 // ALL_JAVA_THREADS iterates through all JavaThreads 3235 ALL_JAVA_THREADS(p) { 3236 tc->do_thread(p); 3237 } 3238 // Someday we could have a table or list of all non-JavaThreads. 3239 // For now, just manually iterate through them. 3240 tc->do_thread(VMThread::vm_thread()); 3241 Universe::heap()->gc_threads_do(tc); 3242 WatcherThread *wt = WatcherThread::watcher_thread(); 3243 // Strictly speaking, the following NULL check isn't sufficient to make sure 3244 // the data for WatcherThread is still valid upon being examined. However, 3245 // considering that WatchThread terminates when the VM is on the way to 3246 // exit at safepoint, the chance of the above is extremely small. The right 3247 // way to prevent termination of WatcherThread would be to acquire 3248 // Terminator_lock, but we can't do that without violating the lock rank 3249 // checking in some cases. 3250 if (wt != NULL) { 3251 tc->do_thread(wt); 3252 } 3253 3254 // If CompilerThreads ever become non-JavaThreads, add them here 3255 } 3256 3257 3258 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3259 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3260 3261 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3262 create_vm_init_libraries(); 3263 } 3264 3265 initialize_class(vmSymbols::java_lang_String(), CHECK); 3266 3267 // Initialize java_lang.System (needed before creating the thread) 3268 initialize_class(vmSymbols::java_lang_System(), CHECK); 3269 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3270 Handle thread_group = create_initial_thread_group(CHECK); 3271 Universe::set_main_thread_group(thread_group()); 3272 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3273 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3274 main_thread->set_threadObj(thread_object); 3275 // Set thread status to running since main thread has 3276 // been started and running. 3277 java_lang_Thread::set_thread_status(thread_object, 3278 java_lang_Thread::RUNNABLE); 3279 3280 // The VM creates & returns objects of this class. Make sure it's initialized. 3281 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3282 3283 // The VM preresolves methods to these classes. Make sure that they get initialized 3284 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3285 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3286 call_initializeSystemClass(CHECK); 3287 3288 // get the Java runtime name after java.lang.System is initialized 3289 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3290 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3291 3292 // an instance of OutOfMemory exception has been allocated earlier 3293 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3294 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3295 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3296 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3297 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3298 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3299 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3300 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3301 } 3302 3303 void Threads::initialize_jsr292_core_classes(TRAPS) { 3304 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3305 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3306 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3307 } 3308 3309 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3310 extern void JDK_Version_init(); 3311 3312 // Check version 3313 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3314 3315 // Initialize the output stream module 3316 ostream_init(); 3317 3318 // Process java launcher properties. 3319 Arguments::process_sun_java_launcher_properties(args); 3320 3321 // Initialize the os module before using TLS 3322 os::init(); 3323 3324 // Initialize system properties. 3325 Arguments::init_system_properties(); 3326 3327 // So that JDK version can be used as a discriminator when parsing arguments 3328 JDK_Version_init(); 3329 3330 // Update/Initialize System properties after JDK version number is known 3331 Arguments::init_version_specific_system_properties(); 3332 3333 // Parse arguments 3334 jint parse_result = Arguments::parse(args); 3335 if (parse_result != JNI_OK) return parse_result; 3336 3337 os::init_before_ergo(); 3338 3339 jint ergo_result = Arguments::apply_ergo(); 3340 if (ergo_result != JNI_OK) return ergo_result; 3341 3342 if (PauseAtStartup) { 3343 os::pause(); 3344 } 3345 3346 HOTSPOT_VM_INIT_BEGIN(); 3347 3348 // Record VM creation timing statistics 3349 TraceVmCreationTime create_vm_timer; 3350 create_vm_timer.start(); 3351 3352 // Timing (must come after argument parsing) 3353 TraceTime timer("Create VM", TraceStartupTime); 3354 3355 // Initialize the os module after parsing the args 3356 jint os_init_2_result = os::init_2(); 3357 if (os_init_2_result != JNI_OK) return os_init_2_result; 3358 3359 jint adjust_after_os_result = Arguments::adjust_after_os(); 3360 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3361 3362 // initialize TLS 3363 ThreadLocalStorage::init(); 3364 3365 // Initialize output stream logging 3366 ostream_init_log(); 3367 3368 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3369 // Must be before create_vm_init_agents() 3370 if (Arguments::init_libraries_at_startup()) { 3371 convert_vm_init_libraries_to_agents(); 3372 } 3373 3374 // Launch -agentlib/-agentpath and converted -Xrun agents 3375 if (Arguments::init_agents_at_startup()) { 3376 create_vm_init_agents(); 3377 } 3378 3379 // Initialize Threads state 3380 _thread_list = NULL; 3381 _number_of_threads = 0; 3382 _number_of_non_daemon_threads = 0; 3383 3384 // Initialize global data structures and create system classes in heap 3385 vm_init_globals(); 3386 3387 // Attach the main thread to this os thread 3388 JavaThread* main_thread = new JavaThread(); 3389 main_thread->set_thread_state(_thread_in_vm); 3390 // must do this before set_active_handles and initialize_thread_local_storage 3391 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3392 // change the stack size recorded here to one based on the java thread 3393 // stacksize. This adjusted size is what is used to figure the placement 3394 // of the guard pages. 3395 main_thread->record_stack_base_and_size(); 3396 main_thread->initialize_thread_local_storage(); 3397 3398 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3399 3400 if (!main_thread->set_as_starting_thread()) { 3401 vm_shutdown_during_initialization( 3402 "Failed necessary internal allocation. Out of swap space"); 3403 delete main_thread; 3404 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3405 return JNI_ENOMEM; 3406 } 3407 3408 // Enable guard page *after* os::create_main_thread(), otherwise it would 3409 // crash Linux VM, see notes in os_linux.cpp. 3410 main_thread->create_stack_guard_pages(); 3411 3412 // Initialize Java-Level synchronization subsystem 3413 ObjectMonitor::Initialize(); 3414 3415 // Initialize global modules 3416 jint status = init_globals(); 3417 if (status != JNI_OK) { 3418 delete main_thread; 3419 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3420 return status; 3421 } 3422 3423 // Should be done after the heap is fully created 3424 main_thread->cache_global_variables(); 3425 3426 HandleMark hm; 3427 3428 { MutexLocker mu(Threads_lock); 3429 Threads::add(main_thread); 3430 } 3431 3432 // Any JVMTI raw monitors entered in onload will transition into 3433 // real raw monitor. VM is setup enough here for raw monitor enter. 3434 JvmtiExport::transition_pending_onload_raw_monitors(); 3435 3436 // Create the VMThread 3437 { TraceTime timer("Start VMThread", TraceStartupTime); 3438 VMThread::create(); 3439 Thread* vmthread = VMThread::vm_thread(); 3440 3441 if (!os::create_thread(vmthread, os::vm_thread)) { 3442 vm_exit_during_initialization("Cannot create VM thread. " 3443 "Out of system resources."); 3444 } 3445 3446 // Wait for the VM thread to become ready, and VMThread::run to initialize 3447 // Monitors can have spurious returns, must always check another state flag 3448 { 3449 MutexLocker ml(Notify_lock); 3450 os::start_thread(vmthread); 3451 while (vmthread->active_handles() == NULL) { 3452 Notify_lock->wait(); 3453 } 3454 } 3455 } 3456 3457 assert(Universe::is_fully_initialized(), "not initialized"); 3458 if (VerifyDuringStartup) { 3459 // Make sure we're starting with a clean slate. 3460 VM_Verify verify_op; 3461 VMThread::execute(&verify_op); 3462 } 3463 3464 Thread* THREAD = Thread::current(); 3465 3466 // At this point, the Universe is initialized, but we have not executed 3467 // any byte code. Now is a good time (the only time) to dump out the 3468 // internal state of the JVM for sharing. 3469 if (DumpSharedSpaces) { 3470 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3471 ShouldNotReachHere(); 3472 } 3473 3474 // Always call even when there are not JVMTI environments yet, since environments 3475 // may be attached late and JVMTI must track phases of VM execution 3476 JvmtiExport::enter_start_phase(); 3477 3478 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3479 JvmtiExport::post_vm_start(); 3480 3481 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3482 3483 // We need this for ClassDataSharing - the initial vm.info property is set 3484 // with the default value of CDS "sharing" which may be reset through 3485 // command line options. 3486 reset_vm_info_property(CHECK_JNI_ERR); 3487 3488 quicken_jni_functions(); 3489 3490 // Must be run after init_ft which initializes ft_enabled 3491 if (TRACE_INITIALIZE() != JNI_OK) { 3492 vm_exit_during_initialization("Failed to initialize tracing backend"); 3493 } 3494 3495 // Set flag that basic initialization has completed. Used by exceptions and various 3496 // debug stuff, that does not work until all basic classes have been initialized. 3497 set_init_completed(); 3498 3499 Metaspace::post_initialize(); 3500 3501 HOTSPOT_VM_INIT_END(); 3502 3503 // record VM initialization completion time 3504 #if INCLUDE_MANAGEMENT 3505 Management::record_vm_init_completed(); 3506 #endif // INCLUDE_MANAGEMENT 3507 3508 // Compute system loader. Note that this has to occur after set_init_completed, since 3509 // valid exceptions may be thrown in the process. 3510 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3511 // set_init_completed has just been called, causing exceptions not to be shortcut 3512 // anymore. We call vm_exit_during_initialization directly instead. 3513 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR); 3514 3515 #if INCLUDE_ALL_GCS 3516 // Support for ConcurrentMarkSweep. This should be cleaned up 3517 // and better encapsulated. The ugly nested if test would go away 3518 // once things are properly refactored. XXX YSR 3519 if (UseConcMarkSweepGC || UseG1GC) { 3520 if (UseConcMarkSweepGC) { 3521 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3522 } else { 3523 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3524 } 3525 } 3526 #endif // INCLUDE_ALL_GCS 3527 3528 // Always call even when there are not JVMTI environments yet, since environments 3529 // may be attached late and JVMTI must track phases of VM execution 3530 JvmtiExport::enter_live_phase(); 3531 3532 // Signal Dispatcher needs to be started before VMInit event is posted 3533 os::signal_init(); 3534 3535 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3536 if (!DisableAttachMechanism) { 3537 AttachListener::vm_start(); 3538 if (StartAttachListener || AttachListener::init_at_startup()) { 3539 AttachListener::init(); 3540 } 3541 } 3542 3543 // Launch -Xrun agents 3544 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3545 // back-end can launch with -Xdebug -Xrunjdwp. 3546 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3547 create_vm_init_libraries(); 3548 } 3549 3550 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3551 JvmtiExport::post_vm_initialized(); 3552 3553 if (TRACE_START() != JNI_OK) { 3554 vm_exit_during_initialization("Failed to start tracing backend."); 3555 } 3556 3557 if (CleanChunkPoolAsync) { 3558 Chunk::start_chunk_pool_cleaner_task(); 3559 } 3560 3561 // initialize compiler(s) 3562 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3563 CompileBroker::compilation_init(); 3564 #endif 3565 3566 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3567 // It is done after compilers are initialized, because otherwise compilations of 3568 // signature polymorphic MH intrinsics can be missed 3569 // (see SystemDictionary::find_method_handle_intrinsic). 3570 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3571 3572 #if INCLUDE_MANAGEMENT 3573 Management::initialize(THREAD); 3574 3575 if (HAS_PENDING_EXCEPTION) { 3576 // management agent fails to start possibly due to 3577 // configuration problem and is responsible for printing 3578 // stack trace if appropriate. Simply exit VM. 3579 vm_exit(1); 3580 } 3581 #endif // INCLUDE_MANAGEMENT 3582 3583 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3584 if (MemProfiling) MemProfiler::engage(); 3585 StatSampler::engage(); 3586 if (CheckJNICalls) JniPeriodicChecker::engage(); 3587 3588 BiasedLocking::init(); 3589 3590 #if INCLUDE_RTM_OPT 3591 RTMLockingCounters::init(); 3592 #endif 3593 3594 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3595 call_postVMInitHook(THREAD); 3596 // The Java side of PostVMInitHook.run must deal with all 3597 // exceptions and provide means of diagnosis. 3598 if (HAS_PENDING_EXCEPTION) { 3599 CLEAR_PENDING_EXCEPTION; 3600 } 3601 } 3602 3603 { 3604 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3605 // Make sure the watcher thread can be started by WatcherThread::start() 3606 // or by dynamic enrollment. 3607 WatcherThread::make_startable(); 3608 // Start up the WatcherThread if there are any periodic tasks 3609 // NOTE: All PeriodicTasks should be registered by now. If they 3610 // aren't, late joiners might appear to start slowly (we might 3611 // take a while to process their first tick). 3612 if (PeriodicTask::num_tasks() > 0) { 3613 WatcherThread::start(); 3614 } 3615 } 3616 3617 // Give os specific code one last chance to start 3618 os::init_3(); 3619 3620 create_vm_timer.end(); 3621 #ifdef ASSERT 3622 _vm_complete = true; 3623 #endif 3624 return JNI_OK; 3625 } 3626 3627 // type for the Agent_OnLoad and JVM_OnLoad entry points 3628 extern "C" { 3629 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3630 } 3631 // Find a command line agent library and return its entry point for 3632 // -agentlib: -agentpath: -Xrun 3633 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3634 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 3635 const char *on_load_symbols[], 3636 size_t num_symbol_entries) { 3637 OnLoadEntry_t on_load_entry = NULL; 3638 void *library = NULL; 3639 3640 if (!agent->valid()) { 3641 char buffer[JVM_MAXPATHLEN]; 3642 char ebuf[1024]; 3643 const char *name = agent->name(); 3644 const char *msg = "Could not find agent library "; 3645 3646 // First check to see if agent is statically linked into executable 3647 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3648 library = agent->os_lib(); 3649 } else if (agent->is_absolute_path()) { 3650 library = os::dll_load(name, ebuf, sizeof ebuf); 3651 if (library == NULL) { 3652 const char *sub_msg = " in absolute path, with error: "; 3653 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3654 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3655 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3656 // If we can't find the agent, exit. 3657 vm_exit_during_initialization(buf, NULL); 3658 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3659 } 3660 } else { 3661 // Try to load the agent from the standard dll directory 3662 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3663 name)) { 3664 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3665 } 3666 if (library == NULL) { // Try the local directory 3667 char ns[1] = {0}; 3668 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3669 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3670 } 3671 if (library == NULL) { 3672 const char *sub_msg = " on the library path, with error: "; 3673 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3674 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3675 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3676 // If we can't find the agent, exit. 3677 vm_exit_during_initialization(buf, NULL); 3678 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3679 } 3680 } 3681 } 3682 agent->set_os_lib(library); 3683 agent->set_valid(); 3684 } 3685 3686 // Find the OnLoad function. 3687 on_load_entry = 3688 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3689 false, 3690 on_load_symbols, 3691 num_symbol_entries)); 3692 return on_load_entry; 3693 } 3694 3695 // Find the JVM_OnLoad entry point 3696 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3697 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3698 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3699 } 3700 3701 // Find the Agent_OnLoad entry point 3702 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3703 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3704 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3705 } 3706 3707 // For backwards compatibility with -Xrun 3708 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3709 // treated like -agentpath: 3710 // Must be called before agent libraries are created 3711 void Threads::convert_vm_init_libraries_to_agents() { 3712 AgentLibrary* agent; 3713 AgentLibrary* next; 3714 3715 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3716 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3717 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3718 3719 // If there is an JVM_OnLoad function it will get called later, 3720 // otherwise see if there is an Agent_OnLoad 3721 if (on_load_entry == NULL) { 3722 on_load_entry = lookup_agent_on_load(agent); 3723 if (on_load_entry != NULL) { 3724 // switch it to the agent list -- so that Agent_OnLoad will be called, 3725 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3726 Arguments::convert_library_to_agent(agent); 3727 } else { 3728 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3729 } 3730 } 3731 } 3732 } 3733 3734 // Create agents for -agentlib: -agentpath: and converted -Xrun 3735 // Invokes Agent_OnLoad 3736 // Called very early -- before JavaThreads exist 3737 void Threads::create_vm_init_agents() { 3738 extern struct JavaVM_ main_vm; 3739 AgentLibrary* agent; 3740 3741 JvmtiExport::enter_onload_phase(); 3742 3743 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3744 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3745 3746 if (on_load_entry != NULL) { 3747 // Invoke the Agent_OnLoad function 3748 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3749 if (err != JNI_OK) { 3750 vm_exit_during_initialization("agent library failed to init", agent->name()); 3751 } 3752 } else { 3753 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3754 } 3755 } 3756 JvmtiExport::enter_primordial_phase(); 3757 } 3758 3759 extern "C" { 3760 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3761 } 3762 3763 void Threads::shutdown_vm_agents() { 3764 // Send any Agent_OnUnload notifications 3765 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3766 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3767 extern struct JavaVM_ main_vm; 3768 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3769 3770 // Find the Agent_OnUnload function. 3771 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3772 os::find_agent_function(agent, 3773 false, 3774 on_unload_symbols, 3775 num_symbol_entries)); 3776 3777 // Invoke the Agent_OnUnload function 3778 if (unload_entry != NULL) { 3779 JavaThread* thread = JavaThread::current(); 3780 ThreadToNativeFromVM ttn(thread); 3781 HandleMark hm(thread); 3782 (*unload_entry)(&main_vm); 3783 } 3784 } 3785 } 3786 3787 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3788 // Invokes JVM_OnLoad 3789 void Threads::create_vm_init_libraries() { 3790 extern struct JavaVM_ main_vm; 3791 AgentLibrary* agent; 3792 3793 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3794 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3795 3796 if (on_load_entry != NULL) { 3797 // Invoke the JVM_OnLoad function 3798 JavaThread* thread = JavaThread::current(); 3799 ThreadToNativeFromVM ttn(thread); 3800 HandleMark hm(thread); 3801 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3802 if (err != JNI_OK) { 3803 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3804 } 3805 } else { 3806 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3807 } 3808 } 3809 } 3810 3811 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3812 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3813 3814 JavaThread* java_thread = NULL; 3815 // Sequential search for now. Need to do better optimization later. 3816 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3817 oop tobj = thread->threadObj(); 3818 if (!thread->is_exiting() && 3819 tobj != NULL && 3820 java_tid == java_lang_Thread::thread_id(tobj)) { 3821 java_thread = thread; 3822 break; 3823 } 3824 } 3825 return java_thread; 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 ThreadService::add_thread(p, daemon); 4013 4014 // Possible GC point. 4015 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4016 } 4017 4018 void Threads::remove(JavaThread* p) { 4019 // Extra scope needed for Thread_lock, so we can check 4020 // that we do not remove thread without safepoint code notice 4021 { MutexLocker ml(Threads_lock); 4022 4023 assert(includes(p), "p must be present"); 4024 4025 JavaThread* current = _thread_list; 4026 JavaThread* prev = NULL; 4027 4028 while (current != p) { 4029 prev = current; 4030 current = current->next(); 4031 } 4032 4033 if (prev) { 4034 prev->set_next(current->next()); 4035 } else { 4036 _thread_list = p->next(); 4037 } 4038 _number_of_threads--; 4039 oop threadObj = p->threadObj(); 4040 bool daemon = true; 4041 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4042 _number_of_non_daemon_threads--; 4043 daemon = false; 4044 4045 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4046 // on destroy_vm will wake up. 4047 if (number_of_non_daemon_threads() == 1) { 4048 Threads_lock->notify_all(); 4049 } 4050 } 4051 ThreadService::remove_thread(p, daemon); 4052 4053 // Make sure that safepoint code disregard this thread. This is needed since 4054 // the thread might mess around with locks after this point. This can cause it 4055 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4056 // of this thread since it is removed from the queue. 4057 p->set_terminated_value(); 4058 } // unlock Threads_lock 4059 4060 // Since Events::log uses a lock, we grab it outside the Threads_lock 4061 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4062 } 4063 4064 // Threads_lock must be held when this is called (or must be called during a safepoint) 4065 bool Threads::includes(JavaThread* p) { 4066 assert(Threads_lock->is_locked(), "sanity check"); 4067 ALL_JAVA_THREADS(q) { 4068 if (q == p) { 4069 return true; 4070 } 4071 } 4072 return false; 4073 } 4074 4075 // Operations on the Threads list for GC. These are not explicitly locked, 4076 // but the garbage collector must provide a safe context for them to run. 4077 // In particular, these things should never be called when the Threads_lock 4078 // is held by some other thread. (Note: the Safepoint abstraction also 4079 // uses the Threads_lock to guarantee this property. It also makes sure that 4080 // all threads gets blocked when exiting or starting). 4081 4082 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4083 ALL_JAVA_THREADS(p) { 4084 p->oops_do(f, cld_f, cf); 4085 } 4086 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4087 } 4088 4089 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4090 // Introduce a mechanism allowing parallel threads to claim threads as 4091 // root groups. Overhead should be small enough to use all the time, 4092 // even in sequential code. 4093 SharedHeap* sh = SharedHeap::heap(); 4094 // Cannot yet substitute active_workers for n_par_threads 4095 // because of G1CollectedHeap::verify() use of 4096 // SharedHeap::process_roots(). n_par_threads == 0 will 4097 // turn off parallelism in process_roots while active_workers 4098 // is being used for parallelism elsewhere. 4099 bool is_par = sh->n_par_threads() > 0; 4100 assert(!is_par || 4101 (SharedHeap::heap()->n_par_threads() == 4102 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4103 int cp = SharedHeap::heap()->strong_roots_parity(); 4104 ALL_JAVA_THREADS(p) { 4105 if (p->claim_oops_do(is_par, cp)) { 4106 p->oops_do(f, cld_f, cf); 4107 } 4108 } 4109 VMThread* vmt = VMThread::vm_thread(); 4110 if (vmt->claim_oops_do(is_par, cp)) { 4111 vmt->oops_do(f, cld_f, cf); 4112 } 4113 } 4114 4115 #if INCLUDE_ALL_GCS 4116 // Used by ParallelScavenge 4117 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4118 ALL_JAVA_THREADS(p) { 4119 q->enqueue(new ThreadRootsTask(p)); 4120 } 4121 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4122 } 4123 4124 // Used by Parallel Old 4125 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4126 ALL_JAVA_THREADS(p) { 4127 q->enqueue(new ThreadRootsMarkingTask(p)); 4128 } 4129 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4130 } 4131 #endif // INCLUDE_ALL_GCS 4132 4133 void Threads::nmethods_do(CodeBlobClosure* cf) { 4134 ALL_JAVA_THREADS(p) { 4135 p->nmethods_do(cf); 4136 } 4137 VMThread::vm_thread()->nmethods_do(cf); 4138 } 4139 4140 void Threads::metadata_do(void f(Metadata*)) { 4141 ALL_JAVA_THREADS(p) { 4142 p->metadata_do(f); 4143 } 4144 } 4145 4146 void Threads::deoptimized_wrt_marked_nmethods() { 4147 ALL_JAVA_THREADS(p) { 4148 p->deoptimized_wrt_marked_nmethods(); 4149 } 4150 } 4151 4152 4153 // Get count Java threads that are waiting to enter the specified monitor. 4154 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4155 address monitor, 4156 bool doLock) { 4157 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4158 "must grab Threads_lock or be at safepoint"); 4159 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4160 4161 int i = 0; 4162 { 4163 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4164 ALL_JAVA_THREADS(p) { 4165 if (p->is_Compiler_thread()) continue; 4166 4167 address pending = (address)p->current_pending_monitor(); 4168 if (pending == monitor) { // found a match 4169 if (i < count) result->append(p); // save the first count matches 4170 i++; 4171 } 4172 } 4173 } 4174 return result; 4175 } 4176 4177 4178 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, 4179 bool doLock) { 4180 assert(doLock || 4181 Threads_lock->owned_by_self() || 4182 SafepointSynchronize::is_at_safepoint(), 4183 "must grab Threads_lock or be at safepoint"); 4184 4185 // NULL owner means not locked so we can skip the search 4186 if (owner == NULL) return NULL; 4187 4188 { 4189 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4190 ALL_JAVA_THREADS(p) { 4191 // first, see if owner is the address of a Java thread 4192 if (owner == (address)p) return p; 4193 } 4194 } 4195 // Cannot assert on lack of success here since this function may be 4196 // used by code that is trying to report useful problem information 4197 // like deadlock detection. 4198 if (UseHeavyMonitors) return NULL; 4199 4200 // If we didn't find a matching Java thread and we didn't force use of 4201 // heavyweight monitors, then the owner is the stack address of the 4202 // Lock Word in the owning Java thread's stack. 4203 // 4204 JavaThread* the_owner = NULL; 4205 { 4206 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4207 ALL_JAVA_THREADS(q) { 4208 if (q->is_lock_owned(owner)) { 4209 the_owner = q; 4210 break; 4211 } 4212 } 4213 } 4214 // cannot assert on lack of success here; see above comment 4215 return the_owner; 4216 } 4217 4218 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4219 void Threads::print_on(outputStream* st, bool print_stacks, 4220 bool internal_format, bool print_concurrent_locks) { 4221 char buf[32]; 4222 st->print_cr("%s", os::local_time_string(buf, sizeof(buf))); 4223 4224 st->print_cr("Full thread dump %s (%s %s):", 4225 Abstract_VM_Version::vm_name(), 4226 Abstract_VM_Version::vm_release(), 4227 Abstract_VM_Version::vm_info_string()); 4228 st->cr(); 4229 4230 #if INCLUDE_ALL_GCS 4231 // Dump concurrent locks 4232 ConcurrentLocksDump concurrent_locks; 4233 if (print_concurrent_locks) { 4234 concurrent_locks.dump_at_safepoint(); 4235 } 4236 #endif // INCLUDE_ALL_GCS 4237 4238 ALL_JAVA_THREADS(p) { 4239 ResourceMark rm; 4240 p->print_on(st); 4241 if (print_stacks) { 4242 if (internal_format) { 4243 p->trace_stack(); 4244 } else { 4245 p->print_stack_on(st); 4246 } 4247 } 4248 st->cr(); 4249 #if INCLUDE_ALL_GCS 4250 if (print_concurrent_locks) { 4251 concurrent_locks.print_locks_on(p, st); 4252 } 4253 #endif // INCLUDE_ALL_GCS 4254 } 4255 4256 VMThread::vm_thread()->print_on(st); 4257 st->cr(); 4258 Universe::heap()->print_gc_threads_on(st); 4259 WatcherThread* wt = WatcherThread::watcher_thread(); 4260 if (wt != NULL) { 4261 wt->print_on(st); 4262 st->cr(); 4263 } 4264 CompileBroker::print_compiler_threads_on(st); 4265 st->flush(); 4266 } 4267 4268 // Threads::print_on_error() is called by fatal error handler. It's possible 4269 // that VM is not at safepoint and/or current thread is inside signal handler. 4270 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4271 // memory (even in resource area), it might deadlock the error handler. 4272 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4273 int buflen) { 4274 bool found_current = false; 4275 st->print_cr("Java Threads: ( => current thread )"); 4276 ALL_JAVA_THREADS(thread) { 4277 bool is_current = (current == thread); 4278 found_current = found_current || is_current; 4279 4280 st->print("%s", is_current ? "=>" : " "); 4281 4282 st->print(PTR_FORMAT, thread); 4283 st->print(" "); 4284 thread->print_on_error(st, buf, buflen); 4285 st->cr(); 4286 } 4287 st->cr(); 4288 4289 st->print_cr("Other Threads:"); 4290 if (VMThread::vm_thread()) { 4291 bool is_current = (current == VMThread::vm_thread()); 4292 found_current = found_current || is_current; 4293 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4294 4295 st->print(PTR_FORMAT, VMThread::vm_thread()); 4296 st->print(" "); 4297 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4298 st->cr(); 4299 } 4300 WatcherThread* wt = WatcherThread::watcher_thread(); 4301 if (wt != NULL) { 4302 bool is_current = (current == wt); 4303 found_current = found_current || is_current; 4304 st->print("%s", is_current ? "=>" : " "); 4305 4306 st->print(PTR_FORMAT, wt); 4307 st->print(" "); 4308 wt->print_on_error(st, buf, buflen); 4309 st->cr(); 4310 } 4311 if (!found_current) { 4312 st->cr(); 4313 st->print("=>" PTR_FORMAT " (exited) ", current); 4314 current->print_on_error(st, buf, buflen); 4315 st->cr(); 4316 } 4317 } 4318 4319 // Internal SpinLock and Mutex 4320 // Based on ParkEvent 4321 4322 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4323 // 4324 // We employ SpinLocks _only for low-contention, fixed-length 4325 // short-duration critical sections where we're concerned 4326 // about native mutex_t or HotSpot Mutex:: latency. 4327 // The mux construct provides a spin-then-block mutual exclusion 4328 // mechanism. 4329 // 4330 // Testing has shown that contention on the ListLock guarding gFreeList 4331 // is common. If we implement ListLock as a simple SpinLock it's common 4332 // for the JVM to devolve to yielding with little progress. This is true 4333 // despite the fact that the critical sections protected by ListLock are 4334 // extremely short. 4335 // 4336 // TODO-FIXME: ListLock should be of type SpinLock. 4337 // We should make this a 1st-class type, integrated into the lock 4338 // hierarchy as leaf-locks. Critically, the SpinLock structure 4339 // should have sufficient padding to avoid false-sharing and excessive 4340 // cache-coherency traffic. 4341 4342 4343 typedef volatile int SpinLockT; 4344 4345 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4346 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4347 return; // normal fast-path return 4348 } 4349 4350 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4351 TEVENT(SpinAcquire - ctx); 4352 int ctr = 0; 4353 int Yields = 0; 4354 for (;;) { 4355 while (*adr != 0) { 4356 ++ctr; 4357 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4358 if (Yields > 5) { 4359 os::naked_short_sleep(1); 4360 } else { 4361 os::naked_yield(); 4362 ++Yields; 4363 } 4364 } else { 4365 SpinPause(); 4366 } 4367 } 4368 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4369 } 4370 } 4371 4372 void Thread::SpinRelease(volatile int * adr) { 4373 assert(*adr != 0, "invariant"); 4374 OrderAccess::fence(); // guarantee at least release consistency. 4375 // Roach-motel semantics. 4376 // It's safe if subsequent LDs and STs float "up" into the critical section, 4377 // but prior LDs and STs within the critical section can't be allowed 4378 // to reorder or float past the ST that releases the lock. 4379 // Loads and stores in the critical section - which appear in program 4380 // order before the store that releases the lock - must also appear 4381 // before the store that releases the lock in memory visibility order. 4382 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4383 // the ST of 0 into the lock-word which releases the lock, so fence 4384 // more than covers this on all platforms. 4385 *adr = 0; 4386 } 4387 4388 // muxAcquire and muxRelease: 4389 // 4390 // * muxAcquire and muxRelease support a single-word lock-word construct. 4391 // The LSB of the word is set IFF the lock is held. 4392 // The remainder of the word points to the head of a singly-linked list 4393 // of threads blocked on the lock. 4394 // 4395 // * The current implementation of muxAcquire-muxRelease uses its own 4396 // dedicated Thread._MuxEvent instance. If we're interested in 4397 // minimizing the peak number of extant ParkEvent instances then 4398 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4399 // as certain invariants were satisfied. Specifically, care would need 4400 // to be taken with regards to consuming unpark() "permits". 4401 // A safe rule of thumb is that a thread would never call muxAcquire() 4402 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4403 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4404 // consume an unpark() permit intended for monitorenter, for instance. 4405 // One way around this would be to widen the restricted-range semaphore 4406 // implemented in park(). Another alternative would be to provide 4407 // multiple instances of the PlatformEvent() for each thread. One 4408 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4409 // 4410 // * Usage: 4411 // -- Only as leaf locks 4412 // -- for short-term locking only as muxAcquire does not perform 4413 // thread state transitions. 4414 // 4415 // Alternatives: 4416 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4417 // but with parking or spin-then-park instead of pure spinning. 4418 // * Use Taura-Oyama-Yonenzawa locks. 4419 // * It's possible to construct a 1-0 lock if we encode the lockword as 4420 // (List,LockByte). Acquire will CAS the full lockword while Release 4421 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4422 // acquiring threads use timers (ParkTimed) to detect and recover from 4423 // the stranding window. Thread/Node structures must be aligned on 256-byte 4424 // boundaries by using placement-new. 4425 // * Augment MCS with advisory back-link fields maintained with CAS(). 4426 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4427 // The validity of the backlinks must be ratified before we trust the value. 4428 // If the backlinks are invalid the exiting thread must back-track through the 4429 // the forward links, which are always trustworthy. 4430 // * Add a successor indication. The LockWord is currently encoded as 4431 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4432 // to provide the usual futile-wakeup optimization. 4433 // See RTStt for details. 4434 // * Consider schedctl.sc_nopreempt to cover the critical section. 4435 // 4436 4437 4438 typedef volatile intptr_t MutexT; // Mux Lock-word 4439 enum MuxBits { LOCKBIT = 1 }; 4440 4441 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4442 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4443 if (w == 0) return; 4444 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4445 return; 4446 } 4447 4448 TEVENT(muxAcquire - Contention); 4449 ParkEvent * const Self = Thread::current()->_MuxEvent; 4450 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4451 for (;;) { 4452 int its = (os::is_MP() ? 100 : 0) + 1; 4453 4454 // Optional spin phase: spin-then-park strategy 4455 while (--its >= 0) { 4456 w = *Lock; 4457 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4458 return; 4459 } 4460 } 4461 4462 Self->reset(); 4463 Self->OnList = intptr_t(Lock); 4464 // The following fence() isn't _strictly necessary as the subsequent 4465 // CAS() both serializes execution and ratifies the fetched *Lock value. 4466 OrderAccess::fence(); 4467 for (;;) { 4468 w = *Lock; 4469 if ((w & LOCKBIT) == 0) { 4470 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4471 Self->OnList = 0; // hygiene - allows stronger asserts 4472 return; 4473 } 4474 continue; // Interference -- *Lock changed -- Just retry 4475 } 4476 assert(w & LOCKBIT, "invariant"); 4477 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4478 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4479 } 4480 4481 while (Self->OnList != 0) { 4482 Self->park(); 4483 } 4484 } 4485 } 4486 4487 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4488 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4489 if (w == 0) return; 4490 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4491 return; 4492 } 4493 4494 TEVENT(muxAcquire - Contention); 4495 ParkEvent * ReleaseAfter = NULL; 4496 if (ev == NULL) { 4497 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4498 } 4499 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4500 for (;;) { 4501 guarantee(ev->OnList == 0, "invariant"); 4502 int its = (os::is_MP() ? 100 : 0) + 1; 4503 4504 // Optional spin phase: spin-then-park strategy 4505 while (--its >= 0) { 4506 w = *Lock; 4507 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4508 if (ReleaseAfter != NULL) { 4509 ParkEvent::Release(ReleaseAfter); 4510 } 4511 return; 4512 } 4513 } 4514 4515 ev->reset(); 4516 ev->OnList = intptr_t(Lock); 4517 // The following fence() isn't _strictly necessary as the subsequent 4518 // CAS() both serializes execution and ratifies the fetched *Lock value. 4519 OrderAccess::fence(); 4520 for (;;) { 4521 w = *Lock; 4522 if ((w & LOCKBIT) == 0) { 4523 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4524 ev->OnList = 0; 4525 // We call ::Release while holding the outer lock, thus 4526 // artificially lengthening the critical section. 4527 // Consider deferring the ::Release() until the subsequent unlock(), 4528 // after we've dropped the outer lock. 4529 if (ReleaseAfter != NULL) { 4530 ParkEvent::Release(ReleaseAfter); 4531 } 4532 return; 4533 } 4534 continue; // Interference -- *Lock changed -- Just retry 4535 } 4536 assert(w & LOCKBIT, "invariant"); 4537 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4538 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4539 } 4540 4541 while (ev->OnList != 0) { 4542 ev->park(); 4543 } 4544 } 4545 } 4546 4547 // Release() must extract a successor from the list and then wake that thread. 4548 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4549 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4550 // Release() would : 4551 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4552 // (B) Extract a successor from the private list "in-hand" 4553 // (C) attempt to CAS() the residual back into *Lock over null. 4554 // If there were any newly arrived threads and the CAS() would fail. 4555 // In that case Release() would detach the RATs, re-merge the list in-hand 4556 // with the RATs and repeat as needed. Alternately, Release() might 4557 // detach and extract a successor, but then pass the residual list to the wakee. 4558 // The wakee would be responsible for reattaching and remerging before it 4559 // competed for the lock. 4560 // 4561 // Both "pop" and DMR are immune from ABA corruption -- there can be 4562 // multiple concurrent pushers, but only one popper or detacher. 4563 // This implementation pops from the head of the list. This is unfair, 4564 // but tends to provide excellent throughput as hot threads remain hot. 4565 // (We wake recently run threads first). 4566 // 4567 // All paths through muxRelease() will execute a CAS. 4568 // Release consistency -- We depend on the CAS in muxRelease() to provide full 4569 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4570 // executed within the critical section are complete and globally visible before the 4571 // store (CAS) to the lock-word that releases the lock becomes globally visible. 4572 void Thread::muxRelease(volatile intptr_t * Lock) { 4573 for (;;) { 4574 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4575 assert(w & LOCKBIT, "invariant"); 4576 if (w == LOCKBIT) return; 4577 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4578 assert(List != NULL, "invariant"); 4579 assert(List->OnList == intptr_t(Lock), "invariant"); 4580 ParkEvent * const nxt = List->ListNext; 4581 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4582 4583 // The following CAS() releases the lock and pops the head element. 4584 // The CAS() also ratifies the previously fetched lock-word value. 4585 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4586 continue; 4587 } 4588 List->OnList = 0; 4589 OrderAccess::fence(); 4590 List->unpark(); 4591 return; 4592 } 4593 } 4594 4595 4596 void Threads::verify() { 4597 ALL_JAVA_THREADS(p) { 4598 p->verify(); 4599 } 4600 VMThread* thread = VMThread::vm_thread(); 4601 if (thread != NULL) thread->verify(); 4602 }