1 /* 2 * Copyright (c) 1997, 2015, 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 "oops/verifyOopClosure.hpp" 46 #include "prims/jvm_misc.hpp" 47 #include "prims/jvmtiExport.hpp" 48 #include "prims/jvmtiThreadState.hpp" 49 #include "prims/privilegedStack.hpp" 50 #include "runtime/arguments.hpp" 51 #include "runtime/atomic.inline.hpp" 52 #include "runtime/biasedLocking.hpp" 53 #include "runtime/deoptimization.hpp" 54 #include "runtime/fprofiler.hpp" 55 #include "runtime/frame.inline.hpp" 56 #include "runtime/init.hpp" 57 #include "runtime/interfaceSupport.hpp" 58 #include "runtime/java.hpp" 59 #include "runtime/javaCalls.hpp" 60 #include "runtime/jniPeriodicChecker.hpp" 61 #include "runtime/memprofiler.hpp" 62 #include "runtime/mutexLocker.hpp" 63 #include "runtime/objectMonitor.hpp" 64 #include "runtime/orderAccess.inline.hpp" 65 #include "runtime/osThread.hpp" 66 #include "runtime/safepoint.hpp" 67 #include "runtime/sharedRuntime.hpp" 68 #include "runtime/statSampler.hpp" 69 #include "runtime/stubRoutines.hpp" 70 #include "runtime/sweeper.hpp" 71 #include "runtime/task.hpp" 72 #include "runtime/thread.inline.hpp" 73 #include "runtime/threadCritical.hpp" 74 #include "runtime/threadLocalStorage.hpp" 75 #include "runtime/vframe.hpp" 76 #include "runtime/vframeArray.hpp" 77 #include "runtime/vframe_hp.hpp" 78 #include "runtime/vmThread.hpp" 79 #include "runtime/vm_operations.hpp" 80 #include "runtime/vm_version.hpp" 81 #include "services/attachListener.hpp" 82 #include "services/management.hpp" 83 #include "services/memTracker.hpp" 84 #include "services/threadService.hpp" 85 #include "trace/tracing.hpp" 86 #include "trace/traceMacros.hpp" 87 #include "utilities/defaultStream.hpp" 88 #include "utilities/dtrace.hpp" 89 #include "utilities/events.hpp" 90 #include "utilities/macros.hpp" 91 #include "utilities/preserveException.hpp" 92 #include "utilities/workgroup.hpp" 93 #if INCLUDE_ALL_GCS 94 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 95 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 96 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 97 #endif // INCLUDE_ALL_GCS 98 #ifdef COMPILER1 99 #include "c1/c1_Compiler.hpp" 100 #endif 101 #ifdef COMPILER2 102 #include "opto/c2compiler.hpp" 103 #include "opto/idealGraphPrinter.hpp" 104 #endif 105 #if INCLUDE_RTM_OPT 106 #include "runtime/rtmLocking.hpp" 107 #endif 108 109 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 110 111 #ifdef DTRACE_ENABLED 112 113 // Only bother with this argument setup if dtrace is available 114 115 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 116 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 117 118 #define DTRACE_THREAD_PROBE(probe, javathread) \ 119 { \ 120 ResourceMark rm(this); \ 121 int len = 0; \ 122 const char* name = (javathread)->get_thread_name(); \ 123 len = strlen(name); \ 124 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 125 (char *) name, len, \ 126 java_lang_Thread::thread_id((javathread)->threadObj()), \ 127 (uintptr_t) (javathread)->osthread()->thread_id(), \ 128 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 129 } 130 131 #else // ndef DTRACE_ENABLED 132 133 #define DTRACE_THREAD_PROBE(probe, javathread) 134 135 #endif // ndef DTRACE_ENABLED 136 137 138 // Class hierarchy 139 // - Thread 140 // - VMThread 141 // - WatcherThread 142 // - ConcurrentMarkSweepThread 143 // - JavaThread 144 // - CompilerThread 145 146 // ======= Thread ======== 147 // Support for forcing alignment of thread objects for biased locking 148 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 149 if (UseBiasedLocking) { 150 const int alignment = markOopDesc::biased_lock_alignment; 151 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 152 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 153 : AllocateHeap(aligned_size, flags, CURRENT_PC, 154 AllocFailStrategy::RETURN_NULL); 155 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 156 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 157 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 158 "JavaThread alignment code overflowed allocated storage"); 159 if (TraceBiasedLocking) { 160 if (aligned_addr != real_malloc_addr) { 161 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 162 real_malloc_addr, aligned_addr); 163 } 164 } 165 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 166 return aligned_addr; 167 } else { 168 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 169 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 170 } 171 } 172 173 void Thread::operator delete(void* p) { 174 if (UseBiasedLocking) { 175 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 176 FreeHeap(real_malloc_addr); 177 } else { 178 FreeHeap(p); 179 } 180 } 181 182 183 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 184 // JavaThread 185 186 187 Thread::Thread() { 188 // stack and get_thread 189 set_stack_base(NULL); 190 set_stack_size(0); 191 set_self_raw_id(0); 192 set_lgrp_id(-1); 193 194 // allocated data structures 195 set_osthread(NULL); 196 set_resource_area(new (mtThread)ResourceArea()); 197 DEBUG_ONLY(_current_resource_mark = NULL;) 198 set_handle_area(new (mtThread) HandleArea(NULL)); 199 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 200 set_active_handles(NULL); 201 set_free_handle_block(NULL); 202 set_last_handle_mark(NULL); 203 204 // This initial value ==> never claimed. 205 _oops_do_parity = 0; 206 207 // the handle mark links itself to last_handle_mark 208 new HandleMark(this); 209 210 // plain initialization 211 debug_only(_owned_locks = NULL;) 212 debug_only(_allow_allocation_count = 0;) 213 NOT_PRODUCT(_allow_safepoint_count = 0;) 214 NOT_PRODUCT(_skip_gcalot = false;) 215 _jvmti_env_iteration_count = 0; 216 set_allocated_bytes(0); 217 _vm_operation_started_count = 0; 218 _vm_operation_completed_count = 0; 219 _current_pending_monitor = NULL; 220 _current_pending_monitor_is_from_java = true; 221 _current_waiting_monitor = NULL; 222 _num_nested_signal = 0; 223 omFreeList = NULL; 224 omFreeCount = 0; 225 omFreeProvision = 32; 226 omInUseList = NULL; 227 omInUseCount = 0; 228 229 #ifdef ASSERT 230 _visited_for_critical_count = false; 231 #endif 232 233 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, 234 Monitor::_safepoint_check_sometimes); 235 _suspend_flags = 0; 236 237 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 238 _hashStateX = os::random(); 239 _hashStateY = 842502087; 240 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 241 _hashStateW = 273326509; 242 243 _OnTrap = 0; 244 _schedctl = NULL; 245 _Stalled = 0; 246 _TypeTag = 0x2BAD; 247 248 // Many of the following fields are effectively final - immutable 249 // Note that nascent threads can't use the Native Monitor-Mutex 250 // construct until the _MutexEvent is initialized ... 251 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 252 // we might instead use a stack of ParkEvents that we could provision on-demand. 253 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 254 // and ::Release() 255 _ParkEvent = ParkEvent::Allocate(this); 256 _SleepEvent = ParkEvent::Allocate(this); 257 _MutexEvent = ParkEvent::Allocate(this); 258 _MuxEvent = ParkEvent::Allocate(this); 259 260 #ifdef CHECK_UNHANDLED_OOPS 261 if (CheckUnhandledOops) { 262 _unhandled_oops = new UnhandledOops(this); 263 } 264 #endif // CHECK_UNHANDLED_OOPS 265 #ifdef ASSERT 266 if (UseBiasedLocking) { 267 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 268 assert(this == _real_malloc_address || 269 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 270 "bug in forced alignment of thread objects"); 271 } 272 #endif // ASSERT 273 } 274 275 void Thread::initialize_thread_local_storage() { 276 // Note: Make sure this method only calls 277 // non-blocking operations. Otherwise, it might not work 278 // with the thread-startup/safepoint interaction. 279 280 // During Java thread startup, safepoint code should allow this 281 // method to complete because it may need to allocate memory to 282 // store information for the new thread. 283 284 // initialize structure dependent on thread local storage 285 ThreadLocalStorage::set_thread(this); 286 } 287 288 void Thread::record_stack_base_and_size() { 289 set_stack_base(os::current_stack_base()); 290 set_stack_size(os::current_stack_size()); 291 if (is_Java_thread()) { 292 ((JavaThread*) this)->set_stack_overflow_limit(); 293 } 294 // CR 7190089: on Solaris, primordial thread's stack is adjusted 295 // in initialize_thread(). Without the adjustment, stack size is 296 // incorrect if stack is set to unlimited (ulimit -s unlimited). 297 // So far, only Solaris has real implementation of initialize_thread(). 298 // 299 // set up any platform-specific state. 300 os::initialize_thread(this); 301 302 #if INCLUDE_NMT 303 // record thread's native stack, stack grows downward 304 address stack_low_addr = stack_base() - stack_size(); 305 MemTracker::record_thread_stack(stack_low_addr, stack_size()); 306 #endif // INCLUDE_NMT 307 } 308 309 310 Thread::~Thread() { 311 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 312 ObjectSynchronizer::omFlush(this); 313 314 EVENT_THREAD_DESTRUCT(this); 315 316 // stack_base can be NULL if the thread is never started or exited before 317 // record_stack_base_and_size called. Although, we would like to ensure 318 // that all started threads do call record_stack_base_and_size(), there is 319 // not proper way to enforce that. 320 #if INCLUDE_NMT 321 if (_stack_base != NULL) { 322 address low_stack_addr = stack_base() - stack_size(); 323 MemTracker::release_thread_stack(low_stack_addr, stack_size()); 324 #ifdef ASSERT 325 set_stack_base(NULL); 326 #endif 327 } 328 #endif // INCLUDE_NMT 329 330 // deallocate data structures 331 delete resource_area(); 332 // since the handle marks are using the handle area, we have to deallocated the root 333 // handle mark before deallocating the thread's handle area, 334 assert(last_handle_mark() != NULL, "check we have an element"); 335 delete last_handle_mark(); 336 assert(last_handle_mark() == NULL, "check we have reached the end"); 337 338 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 339 // We NULL out the fields for good hygiene. 340 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 341 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 342 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 343 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 344 345 delete handle_area(); 346 delete metadata_handles(); 347 348 // osthread() can be NULL, if creation of thread failed. 349 if (osthread() != NULL) os::free_thread(osthread()); 350 351 delete _SR_lock; 352 353 // clear thread local storage if the Thread is deleting itself 354 if (this == Thread::current()) { 355 ThreadLocalStorage::set_thread(NULL); 356 } else { 357 // In the case where we're not the current thread, invalidate all the 358 // caches in case some code tries to get the current thread or the 359 // thread that was destroyed, and gets stale information. 360 ThreadLocalStorage::invalidate_all(); 361 } 362 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 363 } 364 365 // NOTE: dummy function for assertion purpose. 366 void Thread::run() { 367 ShouldNotReachHere(); 368 } 369 370 #ifdef ASSERT 371 // Private method to check for dangling thread pointer 372 void check_for_dangling_thread_pointer(Thread *thread) { 373 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 374 "possibility of dangling Thread pointer"); 375 } 376 #endif 377 378 ThreadPriority Thread::get_priority(const Thread* const thread) { 379 ThreadPriority priority; 380 // Can return an error! 381 (void)os::get_priority(thread, priority); 382 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 383 return priority; 384 } 385 386 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 387 debug_only(check_for_dangling_thread_pointer(thread);) 388 // Can return an error! 389 (void)os::set_priority(thread, priority); 390 } 391 392 393 void Thread::start(Thread* thread) { 394 // Start is different from resume in that its safety is guaranteed by context or 395 // being called from a Java method synchronized on the Thread object. 396 if (!DisableStartThread) { 397 if (thread->is_Java_thread()) { 398 // Initialize the thread state to RUNNABLE before starting this thread. 399 // Can not set it after the thread started because we do not know the 400 // exact thread state at that time. It could be in MONITOR_WAIT or 401 // in SLEEPING or some other state. 402 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 403 java_lang_Thread::RUNNABLE); 404 } 405 os::start_thread(thread); 406 } 407 } 408 409 // Enqueue a VM_Operation to do the job for us - sometime later 410 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 411 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 412 VMThread::execute(vm_stop); 413 } 414 415 416 // Check if an external suspend request has completed (or has been 417 // cancelled). Returns true if the thread is externally suspended and 418 // false otherwise. 419 // 420 // The bits parameter returns information about the code path through 421 // the routine. Useful for debugging: 422 // 423 // set in is_ext_suspend_completed(): 424 // 0x00000001 - routine was entered 425 // 0x00000010 - routine return false at end 426 // 0x00000100 - thread exited (return false) 427 // 0x00000200 - suspend request cancelled (return false) 428 // 0x00000400 - thread suspended (return true) 429 // 0x00001000 - thread is in a suspend equivalent state (return true) 430 // 0x00002000 - thread is native and walkable (return true) 431 // 0x00004000 - thread is native_trans and walkable (needed retry) 432 // 433 // set in wait_for_ext_suspend_completion(): 434 // 0x00010000 - routine was entered 435 // 0x00020000 - suspend request cancelled before loop (return false) 436 // 0x00040000 - thread suspended before loop (return true) 437 // 0x00080000 - suspend request cancelled in loop (return false) 438 // 0x00100000 - thread suspended in loop (return true) 439 // 0x00200000 - suspend not completed during retry loop (return false) 440 441 // Helper class for tracing suspend wait debug bits. 442 // 443 // 0x00000100 indicates that the target thread exited before it could 444 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 445 // 0x00080000 each indicate a cancelled suspend request so they don't 446 // count as wait failures either. 447 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 448 449 class TraceSuspendDebugBits : public StackObj { 450 private: 451 JavaThread * jt; 452 bool is_wait; 453 bool called_by_wait; // meaningful when !is_wait 454 uint32_t * bits; 455 456 public: 457 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 458 uint32_t *_bits) { 459 jt = _jt; 460 is_wait = _is_wait; 461 called_by_wait = _called_by_wait; 462 bits = _bits; 463 } 464 465 ~TraceSuspendDebugBits() { 466 if (!is_wait) { 467 #if 1 468 // By default, don't trace bits for is_ext_suspend_completed() calls. 469 // That trace is very chatty. 470 return; 471 #else 472 if (!called_by_wait) { 473 // If tracing for is_ext_suspend_completed() is enabled, then only 474 // trace calls to it from wait_for_ext_suspend_completion() 475 return; 476 } 477 #endif 478 } 479 480 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 481 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 482 MutexLocker ml(Threads_lock); // needed for get_thread_name() 483 ResourceMark rm; 484 485 tty->print_cr( 486 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 487 jt->get_thread_name(), *bits); 488 489 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 490 } 491 } 492 } 493 }; 494 #undef DEBUG_FALSE_BITS 495 496 497 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 498 uint32_t *bits) { 499 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 500 501 bool did_trans_retry = false; // only do thread_in_native_trans retry once 502 bool do_trans_retry; // flag to force the retry 503 504 *bits |= 0x00000001; 505 506 do { 507 do_trans_retry = false; 508 509 if (is_exiting()) { 510 // Thread is in the process of exiting. This is always checked 511 // first to reduce the risk of dereferencing a freed JavaThread. 512 *bits |= 0x00000100; 513 return false; 514 } 515 516 if (!is_external_suspend()) { 517 // Suspend request is cancelled. This is always checked before 518 // is_ext_suspended() to reduce the risk of a rogue resume 519 // confusing the thread that made the suspend request. 520 *bits |= 0x00000200; 521 return false; 522 } 523 524 if (is_ext_suspended()) { 525 // thread is suspended 526 *bits |= 0x00000400; 527 return true; 528 } 529 530 // Now that we no longer do hard suspends of threads running 531 // native code, the target thread can be changing thread state 532 // while we are in this routine: 533 // 534 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 535 // 536 // We save a copy of the thread state as observed at this moment 537 // and make our decision about suspend completeness based on the 538 // copy. This closes the race where the thread state is seen as 539 // _thread_in_native_trans in the if-thread_blocked check, but is 540 // seen as _thread_blocked in if-thread_in_native_trans check. 541 JavaThreadState save_state = thread_state(); 542 543 if (save_state == _thread_blocked && is_suspend_equivalent()) { 544 // If the thread's state is _thread_blocked and this blocking 545 // condition is known to be equivalent to a suspend, then we can 546 // consider the thread to be externally suspended. This means that 547 // the code that sets _thread_blocked has been modified to do 548 // self-suspension if the blocking condition releases. We also 549 // used to check for CONDVAR_WAIT here, but that is now covered by 550 // the _thread_blocked with self-suspension check. 551 // 552 // Return true since we wouldn't be here unless there was still an 553 // external suspend request. 554 *bits |= 0x00001000; 555 return true; 556 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 557 // Threads running native code will self-suspend on native==>VM/Java 558 // transitions. If its stack is walkable (should always be the case 559 // unless this function is called before the actual java_suspend() 560 // call), then the wait is done. 561 *bits |= 0x00002000; 562 return true; 563 } else if (!called_by_wait && !did_trans_retry && 564 save_state == _thread_in_native_trans && 565 frame_anchor()->walkable()) { 566 // The thread is transitioning from thread_in_native to another 567 // thread state. check_safepoint_and_suspend_for_native_trans() 568 // will force the thread to self-suspend. If it hasn't gotten 569 // there yet we may have caught the thread in-between the native 570 // code check above and the self-suspend. Lucky us. If we were 571 // called by wait_for_ext_suspend_completion(), then it 572 // will be doing the retries so we don't have to. 573 // 574 // Since we use the saved thread state in the if-statement above, 575 // there is a chance that the thread has already transitioned to 576 // _thread_blocked by the time we get here. In that case, we will 577 // make a single unnecessary pass through the logic below. This 578 // doesn't hurt anything since we still do the trans retry. 579 580 *bits |= 0x00004000; 581 582 // Once the thread leaves thread_in_native_trans for another 583 // thread state, we break out of this retry loop. We shouldn't 584 // need this flag to prevent us from getting back here, but 585 // sometimes paranoia is good. 586 did_trans_retry = true; 587 588 // We wait for the thread to transition to a more usable state. 589 for (int i = 1; i <= SuspendRetryCount; i++) { 590 // We used to do an "os::yield_all(i)" call here with the intention 591 // that yielding would increase on each retry. However, the parameter 592 // is ignored on Linux which means the yield didn't scale up. Waiting 593 // on the SR_lock below provides a much more predictable scale up for 594 // the delay. It also provides a simple/direct point to check for any 595 // safepoint requests from the VMThread 596 597 // temporarily drops SR_lock while doing wait with safepoint check 598 // (if we're a JavaThread - the WatcherThread can also call this) 599 // and increase delay with each retry 600 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 601 602 // check the actual thread state instead of what we saved above 603 if (thread_state() != _thread_in_native_trans) { 604 // the thread has transitioned to another thread state so 605 // try all the checks (except this one) one more time. 606 do_trans_retry = true; 607 break; 608 } 609 } // end retry loop 610 611 612 } 613 } while (do_trans_retry); 614 615 *bits |= 0x00000010; 616 return false; 617 } 618 619 // Wait for an external suspend request to complete (or be cancelled). 620 // Returns true if the thread is externally suspended and false otherwise. 621 // 622 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 623 uint32_t *bits) { 624 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 625 false /* !called_by_wait */, bits); 626 627 // local flag copies to minimize SR_lock hold time 628 bool is_suspended; 629 bool pending; 630 uint32_t reset_bits; 631 632 // set a marker so is_ext_suspend_completed() knows we are the caller 633 *bits |= 0x00010000; 634 635 // We use reset_bits to reinitialize the bits value at the top of 636 // each retry loop. This allows the caller to make use of any 637 // unused bits for their own marking purposes. 638 reset_bits = *bits; 639 640 { 641 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 642 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 643 delay, bits); 644 pending = is_external_suspend(); 645 } 646 // must release SR_lock to allow suspension to complete 647 648 if (!pending) { 649 // A cancelled suspend request is the only false return from 650 // is_ext_suspend_completed() that keeps us from entering the 651 // retry loop. 652 *bits |= 0x00020000; 653 return false; 654 } 655 656 if (is_suspended) { 657 *bits |= 0x00040000; 658 return true; 659 } 660 661 for (int i = 1; i <= retries; i++) { 662 *bits = reset_bits; // reinit to only track last retry 663 664 // We used to do an "os::yield_all(i)" call here with the intention 665 // that yielding would increase on each retry. However, the parameter 666 // is ignored on Linux which means the yield didn't scale up. Waiting 667 // on the SR_lock below provides a much more predictable scale up for 668 // the delay. It also provides a simple/direct point to check for any 669 // safepoint requests from the VMThread 670 671 { 672 MutexLocker ml(SR_lock()); 673 // wait with safepoint check (if we're a JavaThread - the WatcherThread 674 // can also call this) and increase delay with each retry 675 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 676 677 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 678 delay, bits); 679 680 // It is possible for the external suspend request to be cancelled 681 // (by a resume) before the actual suspend operation is completed. 682 // Refresh our local copy to see if we still need to wait. 683 pending = is_external_suspend(); 684 } 685 686 if (!pending) { 687 // A cancelled suspend request is the only false return from 688 // is_ext_suspend_completed() that keeps us from staying in the 689 // retry loop. 690 *bits |= 0x00080000; 691 return false; 692 } 693 694 if (is_suspended) { 695 *bits |= 0x00100000; 696 return true; 697 } 698 } // end retry loop 699 700 // thread did not suspend after all our retries 701 *bits |= 0x00200000; 702 return false; 703 } 704 705 #ifndef PRODUCT 706 void JavaThread::record_jump(address target, address instr, const char* file, 707 int line) { 708 709 // This should not need to be atomic as the only way for simultaneous 710 // updates is via interrupts. Even then this should be rare or non-existent 711 // and we don't care that much anyway. 712 713 int index = _jmp_ring_index; 714 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 715 _jmp_ring[index]._target = (intptr_t) target; 716 _jmp_ring[index]._instruction = (intptr_t) instr; 717 _jmp_ring[index]._file = file; 718 _jmp_ring[index]._line = line; 719 } 720 #endif // PRODUCT 721 722 // Called by flat profiler 723 // Callers have already called wait_for_ext_suspend_completion 724 // The assertion for that is currently too complex to put here: 725 bool JavaThread::profile_last_Java_frame(frame* _fr) { 726 bool gotframe = false; 727 // self suspension saves needed state. 728 if (has_last_Java_frame() && _anchor.walkable()) { 729 *_fr = pd_last_frame(); 730 gotframe = true; 731 } 732 return gotframe; 733 } 734 735 void Thread::interrupt(Thread* thread) { 736 debug_only(check_for_dangling_thread_pointer(thread);) 737 os::interrupt(thread); 738 } 739 740 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 741 debug_only(check_for_dangling_thread_pointer(thread);) 742 // Note: If clear_interrupted==false, this simply fetches and 743 // returns the value of the field osthread()->interrupted(). 744 return os::is_interrupted(thread, clear_interrupted); 745 } 746 747 748 // GC Support 749 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 750 jint thread_parity = _oops_do_parity; 751 if (thread_parity != strong_roots_parity) { 752 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 753 if (res == thread_parity) { 754 return true; 755 } else { 756 guarantee(res == strong_roots_parity, "Or else what?"); 757 return false; 758 } 759 } 760 return false; 761 } 762 763 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 764 active_handles()->oops_do(f); 765 // Do oop for ThreadShadow 766 f->do_oop((oop*)&_pending_exception); 767 handle_area()->oops_do(f); 768 } 769 770 void Thread::nmethods_do(CodeBlobClosure* cf) { 771 // no nmethods in a generic thread... 772 } 773 774 void Thread::metadata_handles_do(void f(Metadata*)) { 775 // Only walk the Handles in Thread. 776 if (metadata_handles() != NULL) { 777 for (int i = 0; i< metadata_handles()->length(); i++) { 778 f(metadata_handles()->at(i)); 779 } 780 } 781 } 782 783 void Thread::print_on(outputStream* st) const { 784 // get_priority assumes osthread initialized 785 if (osthread() != NULL) { 786 int os_prio; 787 if (os::get_native_priority(this, &os_prio) == OS_OK) { 788 st->print("os_prio=%d ", os_prio); 789 } 790 st->print("tid=" INTPTR_FORMAT " ", this); 791 ext().print_on(st); 792 osthread()->print_on(st); 793 } 794 debug_only(if (WizardMode) print_owned_locks_on(st);) 795 } 796 797 // Thread::print_on_error() is called by fatal error handler. Don't use 798 // any lock or allocate memory. 799 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 800 if (is_VM_thread()) st->print("VMThread"); 801 else if (is_Compiler_thread()) st->print("CompilerThread"); 802 else if (is_Java_thread()) st->print("JavaThread"); 803 else if (is_GC_task_thread()) st->print("GCTaskThread"); 804 else if (is_Watcher_thread()) st->print("WatcherThread"); 805 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 806 else st->print("Thread"); 807 808 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 809 _stack_base - _stack_size, _stack_base); 810 811 if (osthread()) { 812 st->print(" [id=%d]", osthread()->thread_id()); 813 } 814 } 815 816 #ifdef ASSERT 817 void Thread::print_owned_locks_on(outputStream* st) const { 818 Monitor *cur = _owned_locks; 819 if (cur == NULL) { 820 st->print(" (no locks) "); 821 } else { 822 st->print_cr(" Locks owned:"); 823 while (cur) { 824 cur->print_on(st); 825 cur = cur->next(); 826 } 827 } 828 } 829 830 static int ref_use_count = 0; 831 832 bool Thread::owns_locks_but_compiled_lock() const { 833 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 834 if (cur != Compile_lock) return true; 835 } 836 return false; 837 } 838 839 840 #endif 841 842 #ifndef PRODUCT 843 844 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 845 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 846 // no threads which allow_vm_block's are held 847 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 848 // Check if current thread is allowed to block at a safepoint 849 if (!(_allow_safepoint_count == 0)) { 850 fatal("Possible safepoint reached by thread that does not allow it"); 851 } 852 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 853 fatal("LEAF method calling lock?"); 854 } 855 856 #ifdef ASSERT 857 if (potential_vm_operation && is_Java_thread() 858 && !Universe::is_bootstrapping()) { 859 // Make sure we do not hold any locks that the VM thread also uses. 860 // This could potentially lead to deadlocks 861 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 862 // Threads_lock is special, since the safepoint synchronization will not start before this is 863 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 864 // since it is used to transfer control between JavaThreads and the VMThread 865 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 866 if ((cur->allow_vm_block() && 867 cur != Threads_lock && 868 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 869 cur != VMOperationRequest_lock && 870 cur != VMOperationQueue_lock) || 871 cur->rank() == Mutex::special) { 872 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name())); 873 } 874 } 875 } 876 877 if (GCALotAtAllSafepoints) { 878 // We could enter a safepoint here and thus have a gc 879 InterfaceSupport::check_gc_alot(); 880 } 881 #endif 882 } 883 #endif 884 885 bool Thread::is_in_stack(address adr) const { 886 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 887 address end = os::current_stack_pointer(); 888 // Allow non Java threads to call this without stack_base 889 if (_stack_base == NULL) return true; 890 if (stack_base() >= adr && adr >= end) return true; 891 892 return false; 893 } 894 895 896 bool Thread::is_in_usable_stack(address adr) const { 897 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 898 size_t usable_stack_size = _stack_size - stack_guard_size; 899 900 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 901 } 902 903 904 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 905 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 906 // used for compilation in the future. If that change is made, the need for these methods 907 // should be revisited, and they should be removed if possible. 908 909 bool Thread::is_lock_owned(address adr) const { 910 return on_local_stack(adr); 911 } 912 913 bool Thread::set_as_starting_thread() { 914 // NOTE: this must be called inside the main thread. 915 return os::create_main_thread((JavaThread*)this); 916 } 917 918 static void initialize_class(Symbol* class_name, TRAPS) { 919 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 920 InstanceKlass::cast(klass)->initialize(CHECK); 921 } 922 923 924 // Creates the initial ThreadGroup 925 static Handle create_initial_thread_group(TRAPS) { 926 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 927 instanceKlassHandle klass (THREAD, k); 928 929 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 930 { 931 JavaValue result(T_VOID); 932 JavaCalls::call_special(&result, 933 system_instance, 934 klass, 935 vmSymbols::object_initializer_name(), 936 vmSymbols::void_method_signature(), 937 CHECK_NH); 938 } 939 Universe::set_system_thread_group(system_instance()); 940 941 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 942 { 943 JavaValue result(T_VOID); 944 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 945 JavaCalls::call_special(&result, 946 main_instance, 947 klass, 948 vmSymbols::object_initializer_name(), 949 vmSymbols::threadgroup_string_void_signature(), 950 system_instance, 951 string, 952 CHECK_NH); 953 } 954 return main_instance; 955 } 956 957 // Creates the initial Thread 958 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 959 TRAPS) { 960 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 961 instanceKlassHandle klass (THREAD, k); 962 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 963 964 java_lang_Thread::set_thread(thread_oop(), thread); 965 java_lang_Thread::set_priority(thread_oop(), NormPriority); 966 thread->set_threadObj(thread_oop()); 967 968 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 969 970 JavaValue result(T_VOID); 971 JavaCalls::call_special(&result, thread_oop, 972 klass, 973 vmSymbols::object_initializer_name(), 974 vmSymbols::threadgroup_string_void_signature(), 975 thread_group, 976 string, 977 CHECK_NULL); 978 return thread_oop(); 979 } 980 981 static void call_initializeSystemClass(TRAPS) { 982 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 983 instanceKlassHandle klass (THREAD, k); 984 985 JavaValue result(T_VOID); 986 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 987 vmSymbols::void_method_signature(), CHECK); 988 } 989 990 char java_runtime_name[128] = ""; 991 char java_runtime_version[128] = ""; 992 993 // extract the JRE name from sun.misc.Version.java_runtime_name 994 static const char* get_java_runtime_name(TRAPS) { 995 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 996 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 997 fieldDescriptor fd; 998 bool found = k != NULL && 999 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1000 vmSymbols::string_signature(), &fd); 1001 if (found) { 1002 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1003 if (name_oop == NULL) { 1004 return NULL; 1005 } 1006 const char* name = java_lang_String::as_utf8_string(name_oop, 1007 java_runtime_name, 1008 sizeof(java_runtime_name)); 1009 return name; 1010 } else { 1011 return NULL; 1012 } 1013 } 1014 1015 // extract the JRE version from sun.misc.Version.java_runtime_version 1016 static const char* get_java_runtime_version(TRAPS) { 1017 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1018 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1019 fieldDescriptor fd; 1020 bool found = k != NULL && 1021 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1022 vmSymbols::string_signature(), &fd); 1023 if (found) { 1024 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1025 if (name_oop == NULL) { 1026 return NULL; 1027 } 1028 const char* name = java_lang_String::as_utf8_string(name_oop, 1029 java_runtime_version, 1030 sizeof(java_runtime_version)); 1031 return name; 1032 } else { 1033 return NULL; 1034 } 1035 } 1036 1037 // General purpose hook into Java code, run once when the VM is initialized. 1038 // The Java library method itself may be changed independently from the VM. 1039 static void call_postVMInitHook(TRAPS) { 1040 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1041 instanceKlassHandle klass (THREAD, k); 1042 if (klass.not_null()) { 1043 JavaValue result(T_VOID); 1044 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1045 vmSymbols::void_method_signature(), 1046 CHECK); 1047 } 1048 } 1049 1050 static void reset_vm_info_property(TRAPS) { 1051 // the vm info string 1052 ResourceMark rm(THREAD); 1053 const char *vm_info = VM_Version::vm_info_string(); 1054 1055 // java.lang.System class 1056 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1057 instanceKlassHandle klass (THREAD, k); 1058 1059 // setProperty arguments 1060 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1061 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1062 1063 // return value 1064 JavaValue r(T_OBJECT); 1065 1066 // public static String setProperty(String key, String value); 1067 JavaCalls::call_static(&r, 1068 klass, 1069 vmSymbols::setProperty_name(), 1070 vmSymbols::string_string_string_signature(), 1071 key_str, 1072 value_str, 1073 CHECK); 1074 } 1075 1076 1077 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 1078 bool daemon, TRAPS) { 1079 assert(thread_group.not_null(), "thread group should be specified"); 1080 assert(threadObj() == NULL, "should only create Java thread object once"); 1081 1082 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1083 instanceKlassHandle klass (THREAD, k); 1084 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1085 1086 java_lang_Thread::set_thread(thread_oop(), this); 1087 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1088 set_threadObj(thread_oop()); 1089 1090 JavaValue result(T_VOID); 1091 if (thread_name != NULL) { 1092 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1093 // Thread gets assigned specified name and null target 1094 JavaCalls::call_special(&result, 1095 thread_oop, 1096 klass, 1097 vmSymbols::object_initializer_name(), 1098 vmSymbols::threadgroup_string_void_signature(), 1099 thread_group, // Argument 1 1100 name, // Argument 2 1101 THREAD); 1102 } else { 1103 // Thread gets assigned name "Thread-nnn" and null target 1104 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1105 JavaCalls::call_special(&result, 1106 thread_oop, 1107 klass, 1108 vmSymbols::object_initializer_name(), 1109 vmSymbols::threadgroup_runnable_void_signature(), 1110 thread_group, // Argument 1 1111 Handle(), // Argument 2 1112 THREAD); 1113 } 1114 1115 1116 if (daemon) { 1117 java_lang_Thread::set_daemon(thread_oop()); 1118 } 1119 1120 if (HAS_PENDING_EXCEPTION) { 1121 return; 1122 } 1123 1124 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass()); 1125 Handle threadObj(THREAD, this->threadObj()); 1126 1127 JavaCalls::call_special(&result, 1128 thread_group, 1129 group, 1130 vmSymbols::add_method_name(), 1131 vmSymbols::thread_void_signature(), 1132 threadObj, // Arg 1 1133 THREAD); 1134 } 1135 1136 // NamedThread -- non-JavaThread subclasses with multiple 1137 // uniquely named instances should derive from this. 1138 NamedThread::NamedThread() : Thread() { 1139 _name = NULL; 1140 _processed_thread = NULL; 1141 } 1142 1143 NamedThread::~NamedThread() { 1144 if (_name != NULL) { 1145 FREE_C_HEAP_ARRAY(char, _name); 1146 _name = NULL; 1147 } 1148 } 1149 1150 void NamedThread::set_name(const char* format, ...) { 1151 guarantee(_name == NULL, "Only get to set name once."); 1152 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1153 guarantee(_name != NULL, "alloc failure"); 1154 va_list ap; 1155 va_start(ap, format); 1156 jio_vsnprintf(_name, max_name_len, format, ap); 1157 va_end(ap); 1158 } 1159 1160 void NamedThread::initialize_named_thread() { 1161 set_native_thread_name(name()); 1162 } 1163 1164 void NamedThread::print_on(outputStream* st) const { 1165 st->print("\"%s\" ", name()); 1166 Thread::print_on(st); 1167 st->cr(); 1168 } 1169 1170 1171 // ======= WatcherThread ======== 1172 1173 // The watcher thread exists to simulate timer interrupts. It should 1174 // be replaced by an abstraction over whatever native support for 1175 // timer interrupts exists on the platform. 1176 1177 WatcherThread* WatcherThread::_watcher_thread = NULL; 1178 bool WatcherThread::_startable = false; 1179 volatile bool WatcherThread::_should_terminate = false; 1180 1181 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1182 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1183 if (os::create_thread(this, os::watcher_thread)) { 1184 _watcher_thread = this; 1185 1186 // Set the watcher thread to the highest OS priority which should not be 1187 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1188 // is created. The only normal thread using this priority is the reference 1189 // handler thread, which runs for very short intervals only. 1190 // If the VMThread's priority is not lower than the WatcherThread profiling 1191 // will be inaccurate. 1192 os::set_priority(this, MaxPriority); 1193 if (!DisableStartThread) { 1194 os::start_thread(this); 1195 } 1196 } 1197 } 1198 1199 int WatcherThread::sleep() const { 1200 // The WatcherThread does not participate in the safepoint protocol 1201 // for the PeriodicTask_lock because it is not a JavaThread. 1202 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1203 1204 if (_should_terminate) { 1205 // check for termination before we do any housekeeping or wait 1206 return 0; // we did not sleep. 1207 } 1208 1209 // remaining will be zero if there are no tasks, 1210 // causing the WatcherThread to sleep until a task is 1211 // enrolled 1212 int remaining = PeriodicTask::time_to_wait(); 1213 int time_slept = 0; 1214 1215 // we expect this to timeout - we only ever get unparked when 1216 // we should terminate or when a new task has been enrolled 1217 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1218 1219 jlong time_before_loop = os::javaTimeNanos(); 1220 1221 while (true) { 1222 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, 1223 remaining); 1224 jlong now = os::javaTimeNanos(); 1225 1226 if (remaining == 0) { 1227 // if we didn't have any tasks we could have waited for a long time 1228 // consider the time_slept zero and reset time_before_loop 1229 time_slept = 0; 1230 time_before_loop = now; 1231 } else { 1232 // need to recalculate since we might have new tasks in _tasks 1233 time_slept = (int) ((now - time_before_loop) / 1000000); 1234 } 1235 1236 // Change to task list or spurious wakeup of some kind 1237 if (timedout || _should_terminate) { 1238 break; 1239 } 1240 1241 remaining = PeriodicTask::time_to_wait(); 1242 if (remaining == 0) { 1243 // Last task was just disenrolled so loop around and wait until 1244 // another task gets enrolled 1245 continue; 1246 } 1247 1248 remaining -= time_slept; 1249 if (remaining <= 0) { 1250 break; 1251 } 1252 } 1253 1254 return time_slept; 1255 } 1256 1257 void WatcherThread::run() { 1258 assert(this == watcher_thread(), "just checking"); 1259 1260 this->record_stack_base_and_size(); 1261 this->initialize_thread_local_storage(); 1262 this->set_native_thread_name(this->name()); 1263 this->set_active_handles(JNIHandleBlock::allocate_block()); 1264 while (true) { 1265 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1266 assert(watcher_thread() == this, "thread consistency check"); 1267 1268 // Calculate how long it'll be until the next PeriodicTask work 1269 // should be done, and sleep that amount of time. 1270 int time_waited = sleep(); 1271 1272 if (is_error_reported()) { 1273 // A fatal error has happened, the error handler(VMError::report_and_die) 1274 // should abort JVM after creating an error log file. However in some 1275 // rare cases, the error handler itself might deadlock. Here we try to 1276 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1277 // 1278 // This code is in WatcherThread because WatcherThread wakes up 1279 // periodically so the fatal error handler doesn't need to do anything; 1280 // also because the WatcherThread is less likely to crash than other 1281 // threads. 1282 1283 for (;;) { 1284 if (!ShowMessageBoxOnError 1285 && (OnError == NULL || OnError[0] == '\0') 1286 && Arguments::abort_hook() == NULL) { 1287 os::sleep(this, 2 * 60 * 1000, false); 1288 fdStream err(defaultStream::output_fd()); 1289 err.print_raw_cr("# [ timer expired, abort... ]"); 1290 // skip atexit/vm_exit/vm_abort hooks 1291 os::die(); 1292 } 1293 1294 // Wake up 5 seconds later, the fatal handler may reset OnError or 1295 // ShowMessageBoxOnError when it is ready to abort. 1296 os::sleep(this, 5 * 1000, false); 1297 } 1298 } 1299 1300 if (_should_terminate) { 1301 // check for termination before posting the next tick 1302 break; 1303 } 1304 1305 PeriodicTask::real_time_tick(time_waited); 1306 } 1307 1308 // Signal that it is terminated 1309 { 1310 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1311 _watcher_thread = NULL; 1312 Terminator_lock->notify(); 1313 } 1314 1315 // Thread destructor usually does this.. 1316 ThreadLocalStorage::set_thread(NULL); 1317 } 1318 1319 void WatcherThread::start() { 1320 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1321 1322 if (watcher_thread() == NULL && _startable) { 1323 _should_terminate = false; 1324 // Create the single instance of WatcherThread 1325 new WatcherThread(); 1326 } 1327 } 1328 1329 void WatcherThread::make_startable() { 1330 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1331 _startable = true; 1332 } 1333 1334 void WatcherThread::stop() { 1335 { 1336 // Follow normal safepoint aware lock enter protocol since the 1337 // WatcherThread is stopped by another JavaThread. 1338 MutexLocker ml(PeriodicTask_lock); 1339 _should_terminate = true; 1340 1341 WatcherThread* watcher = watcher_thread(); 1342 if (watcher != NULL) { 1343 // unpark the WatcherThread so it can see that it should terminate 1344 watcher->unpark(); 1345 } 1346 } 1347 1348 MutexLocker mu(Terminator_lock); 1349 1350 while (watcher_thread() != NULL) { 1351 // This wait should make safepoint checks, wait without a timeout, 1352 // and wait as a suspend-equivalent condition. 1353 // 1354 // Note: If the FlatProfiler is running, then this thread is waiting 1355 // for the WatcherThread to terminate and the WatcherThread, via the 1356 // FlatProfiler task, is waiting for the external suspend request on 1357 // this thread to complete. wait_for_ext_suspend_completion() will 1358 // eventually timeout, but that takes time. Making this wait a 1359 // suspend-equivalent condition solves that timeout problem. 1360 // 1361 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1362 Mutex::_as_suspend_equivalent_flag); 1363 } 1364 } 1365 1366 void WatcherThread::unpark() { 1367 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1368 PeriodicTask_lock->notify(); 1369 } 1370 1371 void WatcherThread::print_on(outputStream* st) const { 1372 st->print("\"%s\" ", name()); 1373 Thread::print_on(st); 1374 st->cr(); 1375 } 1376 1377 // ======= JavaThread ======== 1378 1379 // A JavaThread is a normal Java thread 1380 1381 void JavaThread::initialize() { 1382 // Initialize fields 1383 1384 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1385 set_claimed_par_id(UINT_MAX); 1386 1387 set_saved_exception_pc(NULL); 1388 set_threadObj(NULL); 1389 _anchor.clear(); 1390 set_entry_point(NULL); 1391 set_jni_functions(jni_functions()); 1392 set_callee_target(NULL); 1393 set_vm_result(NULL); 1394 set_vm_result_2(NULL); 1395 set_vframe_array_head(NULL); 1396 set_vframe_array_last(NULL); 1397 set_deferred_locals(NULL); 1398 set_deopt_mark(NULL); 1399 set_deopt_nmethod(NULL); 1400 clear_must_deopt_id(); 1401 set_monitor_chunks(NULL); 1402 set_next(NULL); 1403 set_thread_state(_thread_new); 1404 _terminated = _not_terminated; 1405 _privileged_stack_top = NULL; 1406 _array_for_gc = NULL; 1407 _suspend_equivalent = false; 1408 _in_deopt_handler = 0; 1409 _doing_unsafe_access = false; 1410 _stack_guard_state = stack_guard_unused; 1411 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1412 _exception_pc = 0; 1413 _exception_handler_pc = 0; 1414 _is_method_handle_return = 0; 1415 _jvmti_thread_state= NULL; 1416 _should_post_on_exceptions_flag = JNI_FALSE; 1417 _jvmti_get_loaded_classes_closure = NULL; 1418 _interp_only_mode = 0; 1419 _special_runtime_exit_condition = _no_async_condition; 1420 _pending_async_exception = NULL; 1421 _thread_stat = NULL; 1422 _thread_stat = new ThreadStatistics(); 1423 _blocked_on_compilation = false; 1424 _jni_active_critical = 0; 1425 _pending_jni_exception_check_fn = NULL; 1426 _do_not_unlock_if_synchronized = false; 1427 _cached_monitor_info = NULL; 1428 _parker = Parker::Allocate(this); 1429 1430 #ifndef PRODUCT 1431 _jmp_ring_index = 0; 1432 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1433 record_jump(NULL, NULL, NULL, 0); 1434 } 1435 #endif // PRODUCT 1436 1437 set_thread_profiler(NULL); 1438 if (FlatProfiler::is_active()) { 1439 // This is where we would decide to either give each thread it's own profiler 1440 // or use one global one from FlatProfiler, 1441 // or up to some count of the number of profiled threads, etc. 1442 ThreadProfiler* pp = new ThreadProfiler(); 1443 pp->engage(); 1444 set_thread_profiler(pp); 1445 } 1446 1447 // Setup safepoint state info for this thread 1448 ThreadSafepointState::create(this); 1449 1450 debug_only(_java_call_counter = 0); 1451 1452 // JVMTI PopFrame support 1453 _popframe_condition = popframe_inactive; 1454 _popframe_preserved_args = NULL; 1455 _popframe_preserved_args_size = 0; 1456 _frames_to_pop_failed_realloc = 0; 1457 1458 pd_initialize(); 1459 } 1460 1461 #if INCLUDE_ALL_GCS 1462 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1463 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1464 #endif // INCLUDE_ALL_GCS 1465 1466 JavaThread::JavaThread(bool is_attaching_via_jni) : 1467 Thread() 1468 #if INCLUDE_ALL_GCS 1469 , _satb_mark_queue(&_satb_mark_queue_set), 1470 _dirty_card_queue(&_dirty_card_queue_set) 1471 #endif // INCLUDE_ALL_GCS 1472 { 1473 initialize(); 1474 if (is_attaching_via_jni) { 1475 _jni_attach_state = _attaching_via_jni; 1476 } else { 1477 _jni_attach_state = _not_attaching_via_jni; 1478 } 1479 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1480 } 1481 1482 bool JavaThread::reguard_stack(address cur_sp) { 1483 if (_stack_guard_state != stack_guard_yellow_disabled) { 1484 return true; // Stack already guarded or guard pages not needed. 1485 } 1486 1487 if (register_stack_overflow()) { 1488 // For those architectures which have separate register and 1489 // memory stacks, we must check the register stack to see if 1490 // it has overflowed. 1491 return false; 1492 } 1493 1494 // Java code never executes within the yellow zone: the latter is only 1495 // there to provoke an exception during stack banging. If java code 1496 // is executing there, either StackShadowPages should be larger, or 1497 // some exception code in c1, c2 or the interpreter isn't unwinding 1498 // when it should. 1499 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1500 1501 enable_stack_yellow_zone(); 1502 return true; 1503 } 1504 1505 bool JavaThread::reguard_stack(void) { 1506 return reguard_stack(os::current_stack_pointer()); 1507 } 1508 1509 1510 void JavaThread::block_if_vm_exited() { 1511 if (_terminated == _vm_exited) { 1512 // _vm_exited is set at safepoint, and Threads_lock is never released 1513 // we will block here forever 1514 Threads_lock->lock_without_safepoint_check(); 1515 ShouldNotReachHere(); 1516 } 1517 } 1518 1519 1520 // Remove this ifdef when C1 is ported to the compiler interface. 1521 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1522 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1523 1524 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1525 Thread() 1526 #if INCLUDE_ALL_GCS 1527 , _satb_mark_queue(&_satb_mark_queue_set), 1528 _dirty_card_queue(&_dirty_card_queue_set) 1529 #endif // INCLUDE_ALL_GCS 1530 { 1531 initialize(); 1532 _jni_attach_state = _not_attaching_via_jni; 1533 set_entry_point(entry_point); 1534 // Create the native thread itself. 1535 // %note runtime_23 1536 os::ThreadType thr_type = os::java_thread; 1537 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1538 os::java_thread; 1539 os::create_thread(this, thr_type, stack_sz); 1540 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1541 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1542 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1543 // the exception consists of creating the exception object & initializing it, initialization 1544 // will leave the VM via a JavaCall and then all locks must be unlocked). 1545 // 1546 // The thread is still suspended when we reach here. Thread must be explicit started 1547 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1548 // by calling Threads:add. The reason why this is not done here, is because the thread 1549 // object must be fully initialized (take a look at JVM_Start) 1550 } 1551 1552 JavaThread::~JavaThread() { 1553 1554 // JSR166 -- return the parker to the free list 1555 Parker::Release(_parker); 1556 _parker = NULL; 1557 1558 // Free any remaining previous UnrollBlock 1559 vframeArray* old_array = vframe_array_last(); 1560 1561 if (old_array != NULL) { 1562 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1563 old_array->set_unroll_block(NULL); 1564 delete old_info; 1565 delete old_array; 1566 } 1567 1568 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1569 if (deferred != NULL) { 1570 // This can only happen if thread is destroyed before deoptimization occurs. 1571 assert(deferred->length() != 0, "empty array!"); 1572 do { 1573 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1574 deferred->remove_at(0); 1575 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1576 delete dlv; 1577 } while (deferred->length() != 0); 1578 delete deferred; 1579 } 1580 1581 // All Java related clean up happens in exit 1582 ThreadSafepointState::destroy(this); 1583 if (_thread_profiler != NULL) delete _thread_profiler; 1584 if (_thread_stat != NULL) delete _thread_stat; 1585 } 1586 1587 1588 // The first routine called by a new Java thread 1589 void JavaThread::run() { 1590 // initialize thread-local alloc buffer related fields 1591 this->initialize_tlab(); 1592 1593 // used to test validity of stack trace backs 1594 this->record_base_of_stack_pointer(); 1595 1596 // Record real stack base and size. 1597 this->record_stack_base_and_size(); 1598 1599 // Initialize thread local storage; set before calling MutexLocker 1600 this->initialize_thread_local_storage(); 1601 1602 this->create_stack_guard_pages(); 1603 1604 this->cache_global_variables(); 1605 1606 // Thread is now sufficient initialized to be handled by the safepoint code as being 1607 // in the VM. Change thread state from _thread_new to _thread_in_vm 1608 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1609 1610 assert(JavaThread::current() == this, "sanity check"); 1611 assert(!Thread::current()->owns_locks(), "sanity check"); 1612 1613 DTRACE_THREAD_PROBE(start, this); 1614 1615 // This operation might block. We call that after all safepoint checks for a new thread has 1616 // been completed. 1617 this->set_active_handles(JNIHandleBlock::allocate_block()); 1618 1619 if (JvmtiExport::should_post_thread_life()) { 1620 JvmtiExport::post_thread_start(this); 1621 } 1622 1623 EventThreadStart event; 1624 if (event.should_commit()) { 1625 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1626 event.commit(); 1627 } 1628 1629 // We call another function to do the rest so we are sure that the stack addresses used 1630 // from there will be lower than the stack base just computed 1631 thread_main_inner(); 1632 1633 // Note, thread is no longer valid at this point! 1634 } 1635 1636 1637 void JavaThread::thread_main_inner() { 1638 assert(JavaThread::current() == this, "sanity check"); 1639 assert(this->threadObj() != NULL, "just checking"); 1640 1641 // Execute thread entry point unless this thread has a pending exception 1642 // or has been stopped before starting. 1643 // Note: Due to JVM_StopThread we can have pending exceptions already! 1644 if (!this->has_pending_exception() && 1645 !java_lang_Thread::is_stillborn(this->threadObj())) { 1646 { 1647 ResourceMark rm(this); 1648 this->set_native_thread_name(this->get_thread_name()); 1649 } 1650 HandleMark hm(this); 1651 this->entry_point()(this, this); 1652 } 1653 1654 DTRACE_THREAD_PROBE(stop, this); 1655 1656 this->exit(false); 1657 delete this; 1658 } 1659 1660 1661 static void ensure_join(JavaThread* thread) { 1662 // We do not need to grap the Threads_lock, since we are operating on ourself. 1663 Handle threadObj(thread, thread->threadObj()); 1664 assert(threadObj.not_null(), "java thread object must exist"); 1665 ObjectLocker lock(threadObj, thread); 1666 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1667 thread->clear_pending_exception(); 1668 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1669 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1670 // Clear the native thread instance - this makes isAlive return false and allows the join() 1671 // to complete once we've done the notify_all below 1672 java_lang_Thread::set_thread(threadObj(), NULL); 1673 lock.notify_all(thread); 1674 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1675 thread->clear_pending_exception(); 1676 } 1677 1678 1679 // For any new cleanup additions, please check to see if they need to be applied to 1680 // cleanup_failed_attach_current_thread as well. 1681 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1682 assert(this == JavaThread::current(), "thread consistency check"); 1683 1684 HandleMark hm(this); 1685 Handle uncaught_exception(this, this->pending_exception()); 1686 this->clear_pending_exception(); 1687 Handle threadObj(this, this->threadObj()); 1688 assert(threadObj.not_null(), "Java thread object should be created"); 1689 1690 if (get_thread_profiler() != NULL) { 1691 get_thread_profiler()->disengage(); 1692 ResourceMark rm; 1693 get_thread_profiler()->print(get_thread_name()); 1694 } 1695 1696 1697 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1698 { 1699 EXCEPTION_MARK; 1700 1701 CLEAR_PENDING_EXCEPTION; 1702 } 1703 if (!destroy_vm) { 1704 if (uncaught_exception.not_null()) { 1705 EXCEPTION_MARK; 1706 // Call method Thread.dispatchUncaughtException(). 1707 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1708 JavaValue result(T_VOID); 1709 JavaCalls::call_virtual(&result, 1710 threadObj, thread_klass, 1711 vmSymbols::dispatchUncaughtException_name(), 1712 vmSymbols::throwable_void_signature(), 1713 uncaught_exception, 1714 THREAD); 1715 if (HAS_PENDING_EXCEPTION) { 1716 ResourceMark rm(this); 1717 jio_fprintf(defaultStream::error_stream(), 1718 "\nException: %s thrown from the UncaughtExceptionHandler" 1719 " in thread \"%s\"\n", 1720 pending_exception()->klass()->external_name(), 1721 get_thread_name()); 1722 CLEAR_PENDING_EXCEPTION; 1723 } 1724 } 1725 1726 // Called before the java thread exit since we want to read info 1727 // from java_lang_Thread object 1728 EventThreadEnd event; 1729 if (event.should_commit()) { 1730 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1731 event.commit(); 1732 } 1733 1734 // Call after last event on thread 1735 EVENT_THREAD_EXIT(this); 1736 1737 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1738 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1739 // is deprecated anyhow. 1740 if (!is_Compiler_thread()) { 1741 int count = 3; 1742 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1743 EXCEPTION_MARK; 1744 JavaValue result(T_VOID); 1745 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1746 JavaCalls::call_virtual(&result, 1747 threadObj, thread_klass, 1748 vmSymbols::exit_method_name(), 1749 vmSymbols::void_method_signature(), 1750 THREAD); 1751 CLEAR_PENDING_EXCEPTION; 1752 } 1753 } 1754 // notify JVMTI 1755 if (JvmtiExport::should_post_thread_life()) { 1756 JvmtiExport::post_thread_end(this); 1757 } 1758 1759 // We have notified the agents that we are exiting, before we go on, 1760 // we must check for a pending external suspend request and honor it 1761 // in order to not surprise the thread that made the suspend request. 1762 while (true) { 1763 { 1764 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1765 if (!is_external_suspend()) { 1766 set_terminated(_thread_exiting); 1767 ThreadService::current_thread_exiting(this); 1768 break; 1769 } 1770 // Implied else: 1771 // Things get a little tricky here. We have a pending external 1772 // suspend request, but we are holding the SR_lock so we 1773 // can't just self-suspend. So we temporarily drop the lock 1774 // and then self-suspend. 1775 } 1776 1777 ThreadBlockInVM tbivm(this); 1778 java_suspend_self(); 1779 1780 // We're done with this suspend request, but we have to loop around 1781 // and check again. Eventually we will get SR_lock without a pending 1782 // external suspend request and will be able to mark ourselves as 1783 // exiting. 1784 } 1785 // no more external suspends are allowed at this point 1786 } else { 1787 // before_exit() has already posted JVMTI THREAD_END events 1788 } 1789 1790 // Notify waiters on thread object. This has to be done after exit() is called 1791 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1792 // group should have the destroyed bit set before waiters are notified). 1793 ensure_join(this); 1794 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1795 1796 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1797 // held by this thread must be released. A detach operation must only 1798 // get here if there are no Java frames on the stack. Therefore, any 1799 // owned monitors at this point MUST be JNI-acquired monitors which are 1800 // pre-inflated and in the monitor cache. 1801 // 1802 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1803 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1804 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1805 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1806 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1807 } 1808 1809 // These things needs to be done while we are still a Java Thread. Make sure that thread 1810 // is in a consistent state, in case GC happens 1811 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1812 1813 if (active_handles() != NULL) { 1814 JNIHandleBlock* block = active_handles(); 1815 set_active_handles(NULL); 1816 JNIHandleBlock::release_block(block); 1817 } 1818 1819 if (free_handle_block() != NULL) { 1820 JNIHandleBlock* block = free_handle_block(); 1821 set_free_handle_block(NULL); 1822 JNIHandleBlock::release_block(block); 1823 } 1824 1825 // These have to be removed while this is still a valid thread. 1826 remove_stack_guard_pages(); 1827 1828 if (UseTLAB) { 1829 tlab().make_parsable(true); // retire TLAB 1830 } 1831 1832 if (JvmtiEnv::environments_might_exist()) { 1833 JvmtiExport::cleanup_thread(this); 1834 } 1835 1836 // We must flush any deferred card marks before removing a thread from 1837 // the list of active threads. 1838 Universe::heap()->flush_deferred_store_barrier(this); 1839 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1840 1841 #if INCLUDE_ALL_GCS 1842 // We must flush the G1-related buffers before removing a thread 1843 // from the list of active threads. We must do this after any deferred 1844 // card marks have been flushed (above) so that any entries that are 1845 // added to the thread's dirty card queue as a result are not lost. 1846 if (UseG1GC) { 1847 flush_barrier_queues(); 1848 } 1849 #endif // INCLUDE_ALL_GCS 1850 1851 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1852 Threads::remove(this); 1853 } 1854 1855 #if INCLUDE_ALL_GCS 1856 // Flush G1-related queues. 1857 void JavaThread::flush_barrier_queues() { 1858 satb_mark_queue().flush(); 1859 dirty_card_queue().flush(); 1860 } 1861 1862 void JavaThread::initialize_queues() { 1863 assert(!SafepointSynchronize::is_at_safepoint(), 1864 "we should not be at a safepoint"); 1865 1866 ObjPtrQueue& satb_queue = satb_mark_queue(); 1867 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1868 // The SATB queue should have been constructed with its active 1869 // field set to false. 1870 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1871 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1872 // If we are creating the thread during a marking cycle, we should 1873 // set the active field of the SATB queue to true. 1874 if (satb_queue_set.is_active()) { 1875 satb_queue.set_active(true); 1876 } 1877 1878 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1879 // The dirty card queue should have been constructed with its 1880 // active field set to true. 1881 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1882 } 1883 #endif // INCLUDE_ALL_GCS 1884 1885 void JavaThread::cleanup_failed_attach_current_thread() { 1886 if (get_thread_profiler() != NULL) { 1887 get_thread_profiler()->disengage(); 1888 ResourceMark rm; 1889 get_thread_profiler()->print(get_thread_name()); 1890 } 1891 1892 if (active_handles() != NULL) { 1893 JNIHandleBlock* block = active_handles(); 1894 set_active_handles(NULL); 1895 JNIHandleBlock::release_block(block); 1896 } 1897 1898 if (free_handle_block() != NULL) { 1899 JNIHandleBlock* block = free_handle_block(); 1900 set_free_handle_block(NULL); 1901 JNIHandleBlock::release_block(block); 1902 } 1903 1904 // These have to be removed while this is still a valid thread. 1905 remove_stack_guard_pages(); 1906 1907 if (UseTLAB) { 1908 tlab().make_parsable(true); // retire TLAB, if any 1909 } 1910 1911 #if INCLUDE_ALL_GCS 1912 if (UseG1GC) { 1913 flush_barrier_queues(); 1914 } 1915 #endif // INCLUDE_ALL_GCS 1916 1917 Threads::remove(this); 1918 delete this; 1919 } 1920 1921 1922 1923 1924 JavaThread* JavaThread::active() { 1925 Thread* thread = ThreadLocalStorage::thread(); 1926 assert(thread != NULL, "just checking"); 1927 if (thread->is_Java_thread()) { 1928 return (JavaThread*) thread; 1929 } else { 1930 assert(thread->is_VM_thread(), "this must be a vm thread"); 1931 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1932 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1933 assert(ret->is_Java_thread(), "must be a Java thread"); 1934 return ret; 1935 } 1936 } 1937 1938 bool JavaThread::is_lock_owned(address adr) const { 1939 if (Thread::is_lock_owned(adr)) return true; 1940 1941 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1942 if (chunk->contains(adr)) return true; 1943 } 1944 1945 return false; 1946 } 1947 1948 1949 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1950 chunk->set_next(monitor_chunks()); 1951 set_monitor_chunks(chunk); 1952 } 1953 1954 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1955 guarantee(monitor_chunks() != NULL, "must be non empty"); 1956 if (monitor_chunks() == chunk) { 1957 set_monitor_chunks(chunk->next()); 1958 } else { 1959 MonitorChunk* prev = monitor_chunks(); 1960 while (prev->next() != chunk) prev = prev->next(); 1961 prev->set_next(chunk->next()); 1962 } 1963 } 1964 1965 // JVM support. 1966 1967 // Note: this function shouldn't block if it's called in 1968 // _thread_in_native_trans state (such as from 1969 // check_special_condition_for_native_trans()). 1970 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 1971 1972 if (has_last_Java_frame() && has_async_condition()) { 1973 // If we are at a polling page safepoint (not a poll return) 1974 // then we must defer async exception because live registers 1975 // will be clobbered by the exception path. Poll return is 1976 // ok because the call we a returning from already collides 1977 // with exception handling registers and so there is no issue. 1978 // (The exception handling path kills call result registers but 1979 // this is ok since the exception kills the result anyway). 1980 1981 if (is_at_poll_safepoint()) { 1982 // if the code we are returning to has deoptimized we must defer 1983 // the exception otherwise live registers get clobbered on the 1984 // exception path before deoptimization is able to retrieve them. 1985 // 1986 RegisterMap map(this, false); 1987 frame caller_fr = last_frame().sender(&map); 1988 assert(caller_fr.is_compiled_frame(), "what?"); 1989 if (caller_fr.is_deoptimized_frame()) { 1990 if (TraceExceptions) { 1991 ResourceMark rm; 1992 tty->print_cr("deferred async exception at compiled safepoint"); 1993 } 1994 return; 1995 } 1996 } 1997 } 1998 1999 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2000 if (condition == _no_async_condition) { 2001 // Conditions have changed since has_special_runtime_exit_condition() 2002 // was called: 2003 // - if we were here only because of an external suspend request, 2004 // then that was taken care of above (or cancelled) so we are done 2005 // - if we were here because of another async request, then it has 2006 // been cleared between the has_special_runtime_exit_condition() 2007 // and now so again we are done 2008 return; 2009 } 2010 2011 // Check for pending async. exception 2012 if (_pending_async_exception != NULL) { 2013 // Only overwrite an already pending exception, if it is not a threadDeath. 2014 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2015 2016 // We cannot call Exceptions::_throw(...) here because we cannot block 2017 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2018 2019 if (TraceExceptions) { 2020 ResourceMark rm; 2021 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2022 if (has_last_Java_frame()) { 2023 frame f = last_frame(); 2024 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2025 } 2026 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2027 } 2028 _pending_async_exception = NULL; 2029 clear_has_async_exception(); 2030 } 2031 } 2032 2033 if (check_unsafe_error && 2034 condition == _async_unsafe_access_error && !has_pending_exception()) { 2035 condition = _no_async_condition; // done 2036 switch (thread_state()) { 2037 case _thread_in_vm: { 2038 JavaThread* THREAD = this; 2039 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2040 } 2041 case _thread_in_native: { 2042 ThreadInVMfromNative tiv(this); 2043 JavaThread* THREAD = this; 2044 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2045 } 2046 case _thread_in_Java: { 2047 ThreadInVMfromJava tiv(this); 2048 JavaThread* THREAD = this; 2049 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2050 } 2051 default: 2052 ShouldNotReachHere(); 2053 } 2054 } 2055 2056 assert(condition == _no_async_condition || has_pending_exception() || 2057 (!check_unsafe_error && condition == _async_unsafe_access_error), 2058 "must have handled the async condition, if no exception"); 2059 } 2060 2061 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2062 // 2063 // Check for pending external suspend. Internal suspend requests do 2064 // not use handle_special_runtime_exit_condition(). 2065 // If JNIEnv proxies are allowed, don't self-suspend if the target 2066 // thread is not the current thread. In older versions of jdbx, jdbx 2067 // threads could call into the VM with another thread's JNIEnv so we 2068 // can be here operating on behalf of a suspended thread (4432884). 2069 bool do_self_suspend = is_external_suspend_with_lock(); 2070 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2071 // 2072 // Because thread is external suspended the safepoint code will count 2073 // thread as at a safepoint. This can be odd because we can be here 2074 // as _thread_in_Java which would normally transition to _thread_blocked 2075 // at a safepoint. We would like to mark the thread as _thread_blocked 2076 // before calling java_suspend_self like all other callers of it but 2077 // we must then observe proper safepoint protocol. (We can't leave 2078 // _thread_blocked with a safepoint in progress). However we can be 2079 // here as _thread_in_native_trans so we can't use a normal transition 2080 // constructor/destructor pair because they assert on that type of 2081 // transition. We could do something like: 2082 // 2083 // JavaThreadState state = thread_state(); 2084 // set_thread_state(_thread_in_vm); 2085 // { 2086 // ThreadBlockInVM tbivm(this); 2087 // java_suspend_self() 2088 // } 2089 // set_thread_state(_thread_in_vm_trans); 2090 // if (safepoint) block; 2091 // set_thread_state(state); 2092 // 2093 // but that is pretty messy. Instead we just go with the way the 2094 // code has worked before and note that this is the only path to 2095 // java_suspend_self that doesn't put the thread in _thread_blocked 2096 // mode. 2097 2098 frame_anchor()->make_walkable(this); 2099 java_suspend_self(); 2100 2101 // We might be here for reasons in addition to the self-suspend request 2102 // so check for other async requests. 2103 } 2104 2105 if (check_asyncs) { 2106 check_and_handle_async_exceptions(); 2107 } 2108 } 2109 2110 void JavaThread::send_thread_stop(oop java_throwable) { 2111 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2112 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2113 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2114 2115 // Do not throw asynchronous exceptions against the compiler thread 2116 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2117 if (is_Compiler_thread()) return; 2118 2119 { 2120 // Actually throw the Throwable against the target Thread - however 2121 // only if there is no thread death exception installed already. 2122 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2123 // If the topmost frame is a runtime stub, then we are calling into 2124 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2125 // must deoptimize the caller before continuing, as the compiled exception handler table 2126 // may not be valid 2127 if (has_last_Java_frame()) { 2128 frame f = last_frame(); 2129 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2130 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2131 RegisterMap reg_map(this, UseBiasedLocking); 2132 frame compiled_frame = f.sender(®_map); 2133 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2134 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2135 } 2136 } 2137 } 2138 2139 // Set async. pending exception in thread. 2140 set_pending_async_exception(java_throwable); 2141 2142 if (TraceExceptions) { 2143 ResourceMark rm; 2144 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2145 } 2146 // for AbortVMOnException flag 2147 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2148 } 2149 } 2150 2151 2152 // Interrupt thread so it will wake up from a potential wait() 2153 Thread::interrupt(this); 2154 } 2155 2156 // External suspension mechanism. 2157 // 2158 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2159 // to any VM_locks and it is at a transition 2160 // Self-suspension will happen on the transition out of the vm. 2161 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2162 // 2163 // Guarantees on return: 2164 // + Target thread will not execute any new bytecode (that's why we need to 2165 // force a safepoint) 2166 // + Target thread will not enter any new monitors 2167 // 2168 void JavaThread::java_suspend() { 2169 { MutexLocker mu(Threads_lock); 2170 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2171 return; 2172 } 2173 } 2174 2175 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2176 if (!is_external_suspend()) { 2177 // a racing resume has cancelled us; bail out now 2178 return; 2179 } 2180 2181 // suspend is done 2182 uint32_t debug_bits = 0; 2183 // Warning: is_ext_suspend_completed() may temporarily drop the 2184 // SR_lock to allow the thread to reach a stable thread state if 2185 // it is currently in a transient thread state. 2186 if (is_ext_suspend_completed(false /* !called_by_wait */, 2187 SuspendRetryDelay, &debug_bits)) { 2188 return; 2189 } 2190 } 2191 2192 VM_ForceSafepoint vm_suspend; 2193 VMThread::execute(&vm_suspend); 2194 } 2195 2196 // Part II of external suspension. 2197 // A JavaThread self suspends when it detects a pending external suspend 2198 // request. This is usually on transitions. It is also done in places 2199 // where continuing to the next transition would surprise the caller, 2200 // e.g., monitor entry. 2201 // 2202 // Returns the number of times that the thread self-suspended. 2203 // 2204 // Note: DO NOT call java_suspend_self() when you just want to block current 2205 // thread. java_suspend_self() is the second stage of cooperative 2206 // suspension for external suspend requests and should only be used 2207 // to complete an external suspend request. 2208 // 2209 int JavaThread::java_suspend_self() { 2210 int ret = 0; 2211 2212 // we are in the process of exiting so don't suspend 2213 if (is_exiting()) { 2214 clear_external_suspend(); 2215 return ret; 2216 } 2217 2218 assert(_anchor.walkable() || 2219 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2220 "must have walkable stack"); 2221 2222 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2223 2224 assert(!this->is_ext_suspended(), 2225 "a thread trying to self-suspend should not already be suspended"); 2226 2227 if (this->is_suspend_equivalent()) { 2228 // If we are self-suspending as a result of the lifting of a 2229 // suspend equivalent condition, then the suspend_equivalent 2230 // flag is not cleared until we set the ext_suspended flag so 2231 // that wait_for_ext_suspend_completion() returns consistent 2232 // results. 2233 this->clear_suspend_equivalent(); 2234 } 2235 2236 // A racing resume may have cancelled us before we grabbed SR_lock 2237 // above. Or another external suspend request could be waiting for us 2238 // by the time we return from SR_lock()->wait(). The thread 2239 // that requested the suspension may already be trying to walk our 2240 // stack and if we return now, we can change the stack out from under 2241 // it. This would be a "bad thing (TM)" and cause the stack walker 2242 // to crash. We stay self-suspended until there are no more pending 2243 // external suspend requests. 2244 while (is_external_suspend()) { 2245 ret++; 2246 this->set_ext_suspended(); 2247 2248 // _ext_suspended flag is cleared by java_resume() 2249 while (is_ext_suspended()) { 2250 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2251 } 2252 } 2253 2254 return ret; 2255 } 2256 2257 #ifdef ASSERT 2258 // verify the JavaThread has not yet been published in the Threads::list, and 2259 // hence doesn't need protection from concurrent access at this stage 2260 void JavaThread::verify_not_published() { 2261 if (!Threads_lock->owned_by_self()) { 2262 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2263 assert(!Threads::includes(this), 2264 "java thread shouldn't have been published yet!"); 2265 } else { 2266 assert(!Threads::includes(this), 2267 "java thread shouldn't have been published yet!"); 2268 } 2269 } 2270 #endif 2271 2272 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2273 // progress or when _suspend_flags is non-zero. 2274 // Current thread needs to self-suspend if there is a suspend request and/or 2275 // block if a safepoint is in progress. 2276 // Async exception ISN'T checked. 2277 // Note only the ThreadInVMfromNative transition can call this function 2278 // directly and when thread state is _thread_in_native_trans 2279 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2280 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2281 2282 JavaThread *curJT = JavaThread::current(); 2283 bool do_self_suspend = thread->is_external_suspend(); 2284 2285 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2286 2287 // If JNIEnv proxies are allowed, don't self-suspend if the target 2288 // thread is not the current thread. In older versions of jdbx, jdbx 2289 // threads could call into the VM with another thread's JNIEnv so we 2290 // can be here operating on behalf of a suspended thread (4432884). 2291 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2292 JavaThreadState state = thread->thread_state(); 2293 2294 // We mark this thread_blocked state as a suspend-equivalent so 2295 // that a caller to is_ext_suspend_completed() won't be confused. 2296 // The suspend-equivalent state is cleared by java_suspend_self(). 2297 thread->set_suspend_equivalent(); 2298 2299 // If the safepoint code sees the _thread_in_native_trans state, it will 2300 // wait until the thread changes to other thread state. There is no 2301 // guarantee on how soon we can obtain the SR_lock and complete the 2302 // self-suspend request. It would be a bad idea to let safepoint wait for 2303 // too long. Temporarily change the state to _thread_blocked to 2304 // let the VM thread know that this thread is ready for GC. The problem 2305 // of changing thread state is that safepoint could happen just after 2306 // java_suspend_self() returns after being resumed, and VM thread will 2307 // see the _thread_blocked state. We must check for safepoint 2308 // after restoring the state and make sure we won't leave while a safepoint 2309 // is in progress. 2310 thread->set_thread_state(_thread_blocked); 2311 thread->java_suspend_self(); 2312 thread->set_thread_state(state); 2313 // Make sure new state is seen by VM thread 2314 if (os::is_MP()) { 2315 if (UseMembar) { 2316 // Force a fence between the write above and read below 2317 OrderAccess::fence(); 2318 } else { 2319 // Must use this rather than serialization page in particular on Windows 2320 InterfaceSupport::serialize_memory(thread); 2321 } 2322 } 2323 } 2324 2325 if (SafepointSynchronize::do_call_back()) { 2326 // If we are safepointing, then block the caller which may not be 2327 // the same as the target thread (see above). 2328 SafepointSynchronize::block(curJT); 2329 } 2330 2331 if (thread->is_deopt_suspend()) { 2332 thread->clear_deopt_suspend(); 2333 RegisterMap map(thread, false); 2334 frame f = thread->last_frame(); 2335 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2336 f = f.sender(&map); 2337 } 2338 if (f.id() == thread->must_deopt_id()) { 2339 thread->clear_must_deopt_id(); 2340 f.deoptimize(thread); 2341 } else { 2342 fatal("missed deoptimization!"); 2343 } 2344 } 2345 } 2346 2347 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2348 // progress or when _suspend_flags is non-zero. 2349 // Current thread needs to self-suspend if there is a suspend request and/or 2350 // block if a safepoint is in progress. 2351 // Also check for pending async exception (not including unsafe access error). 2352 // Note only the native==>VM/Java barriers can call this function and when 2353 // thread state is _thread_in_native_trans. 2354 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2355 check_safepoint_and_suspend_for_native_trans(thread); 2356 2357 if (thread->has_async_exception()) { 2358 // We are in _thread_in_native_trans state, don't handle unsafe 2359 // access error since that may block. 2360 thread->check_and_handle_async_exceptions(false); 2361 } 2362 } 2363 2364 // This is a variant of the normal 2365 // check_special_condition_for_native_trans with slightly different 2366 // semantics for use by critical native wrappers. It does all the 2367 // normal checks but also performs the transition back into 2368 // thread_in_Java state. This is required so that critical natives 2369 // can potentially block and perform a GC if they are the last thread 2370 // exiting the GC_locker. 2371 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2372 check_special_condition_for_native_trans(thread); 2373 2374 // Finish the transition 2375 thread->set_thread_state(_thread_in_Java); 2376 2377 if (thread->do_critical_native_unlock()) { 2378 ThreadInVMfromJavaNoAsyncException tiv(thread); 2379 GC_locker::unlock_critical(thread); 2380 thread->clear_critical_native_unlock(); 2381 } 2382 } 2383 2384 // We need to guarantee the Threads_lock here, since resumes are not 2385 // allowed during safepoint synchronization 2386 // Can only resume from an external suspension 2387 void JavaThread::java_resume() { 2388 assert_locked_or_safepoint(Threads_lock); 2389 2390 // Sanity check: thread is gone, has started exiting or the thread 2391 // was not externally suspended. 2392 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2393 return; 2394 } 2395 2396 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2397 2398 clear_external_suspend(); 2399 2400 if (is_ext_suspended()) { 2401 clear_ext_suspended(); 2402 SR_lock()->notify_all(); 2403 } 2404 } 2405 2406 void JavaThread::create_stack_guard_pages() { 2407 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2408 address low_addr = stack_base() - stack_size(); 2409 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2410 2411 int allocate = os::allocate_stack_guard_pages(); 2412 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2413 2414 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2415 warning("Attempt to allocate stack guard pages failed."); 2416 return; 2417 } 2418 2419 if (os::guard_memory((char *) low_addr, len)) { 2420 _stack_guard_state = stack_guard_enabled; 2421 } else { 2422 warning("Attempt to protect stack guard pages failed."); 2423 if (os::uncommit_memory((char *) low_addr, len)) { 2424 warning("Attempt to deallocate stack guard pages failed."); 2425 } 2426 } 2427 } 2428 2429 void JavaThread::remove_stack_guard_pages() { 2430 assert(Thread::current() == this, "from different thread"); 2431 if (_stack_guard_state == stack_guard_unused) return; 2432 address low_addr = stack_base() - stack_size(); 2433 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2434 2435 if (os::allocate_stack_guard_pages()) { 2436 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2437 _stack_guard_state = stack_guard_unused; 2438 } else { 2439 warning("Attempt to deallocate stack guard pages failed."); 2440 } 2441 } else { 2442 if (_stack_guard_state == stack_guard_unused) return; 2443 if (os::unguard_memory((char *) low_addr, len)) { 2444 _stack_guard_state = stack_guard_unused; 2445 } else { 2446 warning("Attempt to unprotect stack guard pages failed."); 2447 } 2448 } 2449 } 2450 2451 void JavaThread::enable_stack_yellow_zone() { 2452 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2453 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2454 2455 // The base notation is from the stacks point of view, growing downward. 2456 // We need to adjust it to work correctly with guard_memory() 2457 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2458 2459 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2460 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2461 2462 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2463 _stack_guard_state = stack_guard_enabled; 2464 } else { 2465 warning("Attempt to guard stack yellow zone failed."); 2466 } 2467 enable_register_stack_guard(); 2468 } 2469 2470 void JavaThread::disable_stack_yellow_zone() { 2471 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2472 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2473 2474 // Simply return if called for a thread that does not use guard pages. 2475 if (_stack_guard_state == stack_guard_unused) return; 2476 2477 // The base notation is from the stacks point of view, growing downward. 2478 // We need to adjust it to work correctly with guard_memory() 2479 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2480 2481 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2482 _stack_guard_state = stack_guard_yellow_disabled; 2483 } else { 2484 warning("Attempt to unguard stack yellow zone failed."); 2485 } 2486 disable_register_stack_guard(); 2487 } 2488 2489 void JavaThread::enable_stack_red_zone() { 2490 // The base notation is from the stacks point of view, growing downward. 2491 // We need to adjust it to work correctly with guard_memory() 2492 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2493 address base = stack_red_zone_base() - stack_red_zone_size(); 2494 2495 guarantee(base < stack_base(), "Error calculating stack red zone"); 2496 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2497 2498 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2499 warning("Attempt to guard stack red zone failed."); 2500 } 2501 } 2502 2503 void JavaThread::disable_stack_red_zone() { 2504 // The base notation is from the stacks point of view, growing downward. 2505 // We need to adjust it to work correctly with guard_memory() 2506 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2507 address base = stack_red_zone_base() - stack_red_zone_size(); 2508 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2509 warning("Attempt to unguard stack red zone failed."); 2510 } 2511 } 2512 2513 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2514 // ignore is there is no stack 2515 if (!has_last_Java_frame()) return; 2516 // traverse the stack frames. Starts from top frame. 2517 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2518 frame* fr = fst.current(); 2519 f(fr, fst.register_map()); 2520 } 2521 } 2522 2523 2524 #ifndef PRODUCT 2525 // Deoptimization 2526 // Function for testing deoptimization 2527 void JavaThread::deoptimize() { 2528 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2529 StackFrameStream fst(this, UseBiasedLocking); 2530 bool deopt = false; // Dump stack only if a deopt actually happens. 2531 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2532 // Iterate over all frames in the thread and deoptimize 2533 for (; !fst.is_done(); fst.next()) { 2534 if (fst.current()->can_be_deoptimized()) { 2535 2536 if (only_at) { 2537 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2538 // consists of comma or carriage return separated numbers so 2539 // search for the current bci in that string. 2540 address pc = fst.current()->pc(); 2541 nmethod* nm = (nmethod*) fst.current()->cb(); 2542 ScopeDesc* sd = nm->scope_desc_at(pc); 2543 char buffer[8]; 2544 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2545 size_t len = strlen(buffer); 2546 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2547 while (found != NULL) { 2548 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2549 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2550 // Check that the bci found is bracketed by terminators. 2551 break; 2552 } 2553 found = strstr(found + 1, buffer); 2554 } 2555 if (!found) { 2556 continue; 2557 } 2558 } 2559 2560 if (DebugDeoptimization && !deopt) { 2561 deopt = true; // One-time only print before deopt 2562 tty->print_cr("[BEFORE Deoptimization]"); 2563 trace_frames(); 2564 trace_stack(); 2565 } 2566 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2567 } 2568 } 2569 2570 if (DebugDeoptimization && deopt) { 2571 tty->print_cr("[AFTER Deoptimization]"); 2572 trace_frames(); 2573 } 2574 } 2575 2576 2577 // Make zombies 2578 void JavaThread::make_zombies() { 2579 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2580 if (fst.current()->can_be_deoptimized()) { 2581 // it is a Java nmethod 2582 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2583 nm->make_not_entrant(); 2584 } 2585 } 2586 } 2587 #endif // PRODUCT 2588 2589 2590 void JavaThread::deoptimized_wrt_marked_nmethods() { 2591 if (!has_last_Java_frame()) return; 2592 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2593 StackFrameStream fst(this, UseBiasedLocking); 2594 for (; !fst.is_done(); fst.next()) { 2595 if (fst.current()->should_be_deoptimized()) { 2596 if (LogCompilation && xtty != NULL) { 2597 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2598 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2599 this->name(), nm != NULL ? nm->compile_id() : -1); 2600 } 2601 2602 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2603 } 2604 } 2605 } 2606 2607 2608 // If the caller is a NamedThread, then remember, in the current scope, 2609 // the given JavaThread in its _processed_thread field. 2610 class RememberProcessedThread: public StackObj { 2611 NamedThread* _cur_thr; 2612 public: 2613 RememberProcessedThread(JavaThread* jthr) { 2614 Thread* thread = Thread::current(); 2615 if (thread->is_Named_thread()) { 2616 _cur_thr = (NamedThread *)thread; 2617 _cur_thr->set_processed_thread(jthr); 2618 } else { 2619 _cur_thr = NULL; 2620 } 2621 } 2622 2623 ~RememberProcessedThread() { 2624 if (_cur_thr) { 2625 _cur_thr->set_processed_thread(NULL); 2626 } 2627 } 2628 }; 2629 2630 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2631 // Verify that the deferred card marks have been flushed. 2632 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2633 2634 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2635 // since there may be more than one thread using each ThreadProfiler. 2636 2637 // Traverse the GCHandles 2638 Thread::oops_do(f, cld_f, cf); 2639 2640 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2641 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2642 2643 if (has_last_Java_frame()) { 2644 // Record JavaThread to GC thread 2645 RememberProcessedThread rpt(this); 2646 2647 // Traverse the privileged stack 2648 if (_privileged_stack_top != NULL) { 2649 _privileged_stack_top->oops_do(f); 2650 } 2651 2652 // traverse the registered growable array 2653 if (_array_for_gc != NULL) { 2654 for (int index = 0; index < _array_for_gc->length(); index++) { 2655 f->do_oop(_array_for_gc->adr_at(index)); 2656 } 2657 } 2658 2659 // Traverse the monitor chunks 2660 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2661 chunk->oops_do(f); 2662 } 2663 2664 // Traverse the execution stack 2665 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2666 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2667 } 2668 } 2669 2670 // callee_target is never live across a gc point so NULL it here should 2671 // it still contain a methdOop. 2672 2673 set_callee_target(NULL); 2674 2675 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2676 // If we have deferred set_locals there might be oops waiting to be 2677 // written 2678 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2679 if (list != NULL) { 2680 for (int i = 0; i < list->length(); i++) { 2681 list->at(i)->oops_do(f); 2682 } 2683 } 2684 2685 // Traverse instance variables at the end since the GC may be moving things 2686 // around using this function 2687 f->do_oop((oop*) &_threadObj); 2688 f->do_oop((oop*) &_vm_result); 2689 f->do_oop((oop*) &_exception_oop); 2690 f->do_oop((oop*) &_pending_async_exception); 2691 2692 if (jvmti_thread_state() != NULL) { 2693 jvmti_thread_state()->oops_do(f); 2694 } 2695 } 2696 2697 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2698 Thread::nmethods_do(cf); // (super method is a no-op) 2699 2700 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2701 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2702 2703 if (has_last_Java_frame()) { 2704 // Traverse the execution stack 2705 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2706 fst.current()->nmethods_do(cf); 2707 } 2708 } 2709 } 2710 2711 void JavaThread::metadata_do(void f(Metadata*)) { 2712 if (has_last_Java_frame()) { 2713 // Traverse the execution stack to call f() on the methods in the stack 2714 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2715 fst.current()->metadata_do(f); 2716 } 2717 } else if (is_Compiler_thread()) { 2718 // need to walk ciMetadata in current compile tasks to keep alive. 2719 CompilerThread* ct = (CompilerThread*)this; 2720 if (ct->env() != NULL) { 2721 ct->env()->metadata_do(f); 2722 } 2723 } 2724 } 2725 2726 // Printing 2727 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2728 switch (_thread_state) { 2729 case _thread_uninitialized: return "_thread_uninitialized"; 2730 case _thread_new: return "_thread_new"; 2731 case _thread_new_trans: return "_thread_new_trans"; 2732 case _thread_in_native: return "_thread_in_native"; 2733 case _thread_in_native_trans: return "_thread_in_native_trans"; 2734 case _thread_in_vm: return "_thread_in_vm"; 2735 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2736 case _thread_in_Java: return "_thread_in_Java"; 2737 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2738 case _thread_blocked: return "_thread_blocked"; 2739 case _thread_blocked_trans: return "_thread_blocked_trans"; 2740 default: return "unknown thread state"; 2741 } 2742 } 2743 2744 #ifndef PRODUCT 2745 void JavaThread::print_thread_state_on(outputStream *st) const { 2746 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2747 }; 2748 void JavaThread::print_thread_state() const { 2749 print_thread_state_on(tty); 2750 } 2751 #endif // PRODUCT 2752 2753 // Called by Threads::print() for VM_PrintThreads operation 2754 void JavaThread::print_on(outputStream *st) const { 2755 st->print("\"%s\" ", get_thread_name()); 2756 oop thread_oop = threadObj(); 2757 if (thread_oop != NULL) { 2758 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2759 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2760 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2761 } 2762 Thread::print_on(st); 2763 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2764 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2765 if (thread_oop != NULL) { 2766 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2767 } 2768 #ifndef PRODUCT 2769 print_thread_state_on(st); 2770 _safepoint_state->print_on(st); 2771 #endif // PRODUCT 2772 } 2773 2774 // Called by fatal error handler. The difference between this and 2775 // JavaThread::print() is that we can't grab lock or allocate memory. 2776 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2777 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2778 oop thread_obj = threadObj(); 2779 if (thread_obj != NULL) { 2780 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2781 } 2782 st->print(" ["); 2783 st->print("%s", _get_thread_state_name(_thread_state)); 2784 if (osthread()) { 2785 st->print(", id=%d", osthread()->thread_id()); 2786 } 2787 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2788 _stack_base - _stack_size, _stack_base); 2789 st->print("]"); 2790 return; 2791 } 2792 2793 // Verification 2794 2795 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2796 2797 void JavaThread::verify() { 2798 // Verify oops in the thread. 2799 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2800 2801 // Verify the stack frames. 2802 frames_do(frame_verify); 2803 } 2804 2805 // CR 6300358 (sub-CR 2137150) 2806 // Most callers of this method assume that it can't return NULL but a 2807 // thread may not have a name whilst it is in the process of attaching to 2808 // the VM - see CR 6412693, and there are places where a JavaThread can be 2809 // seen prior to having it's threadObj set (eg JNI attaching threads and 2810 // if vm exit occurs during initialization). These cases can all be accounted 2811 // for such that this method never returns NULL. 2812 const char* JavaThread::get_thread_name() const { 2813 #ifdef ASSERT 2814 // early safepoints can hit while current thread does not yet have TLS 2815 if (!SafepointSynchronize::is_at_safepoint()) { 2816 Thread *cur = Thread::current(); 2817 if (!(cur->is_Java_thread() && cur == this)) { 2818 // Current JavaThreads are allowed to get their own name without 2819 // the Threads_lock. 2820 assert_locked_or_safepoint(Threads_lock); 2821 } 2822 } 2823 #endif // ASSERT 2824 return get_thread_name_string(); 2825 } 2826 2827 // Returns a non-NULL representation of this thread's name, or a suitable 2828 // descriptive string if there is no set name 2829 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2830 const char* name_str; 2831 oop thread_obj = threadObj(); 2832 if (thread_obj != NULL) { 2833 oop name = java_lang_Thread::name(thread_obj); 2834 if (name != NULL) { 2835 if (buf == NULL) { 2836 name_str = java_lang_String::as_utf8_string(name); 2837 } else { 2838 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 2839 } 2840 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2841 name_str = "<no-name - thread is attaching>"; 2842 } else { 2843 name_str = Thread::name(); 2844 } 2845 } else { 2846 name_str = Thread::name(); 2847 } 2848 assert(name_str != NULL, "unexpected NULL thread name"); 2849 return name_str; 2850 } 2851 2852 2853 const char* JavaThread::get_threadgroup_name() const { 2854 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2855 oop thread_obj = threadObj(); 2856 if (thread_obj != NULL) { 2857 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2858 if (thread_group != NULL) { 2859 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2860 // ThreadGroup.name can be null 2861 if (name != NULL) { 2862 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2863 return str; 2864 } 2865 } 2866 } 2867 return NULL; 2868 } 2869 2870 const char* JavaThread::get_parent_name() const { 2871 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2872 oop thread_obj = threadObj(); 2873 if (thread_obj != NULL) { 2874 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2875 if (thread_group != NULL) { 2876 oop parent = java_lang_ThreadGroup::parent(thread_group); 2877 if (parent != NULL) { 2878 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2879 // ThreadGroup.name can be null 2880 if (name != NULL) { 2881 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2882 return str; 2883 } 2884 } 2885 } 2886 } 2887 return NULL; 2888 } 2889 2890 ThreadPriority JavaThread::java_priority() const { 2891 oop thr_oop = threadObj(); 2892 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2893 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2894 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2895 return priority; 2896 } 2897 2898 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2899 2900 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2901 // Link Java Thread object <-> C++ Thread 2902 2903 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2904 // and put it into a new Handle. The Handle "thread_oop" can then 2905 // be used to pass the C++ thread object to other methods. 2906 2907 // Set the Java level thread object (jthread) field of the 2908 // new thread (a JavaThread *) to C++ thread object using the 2909 // "thread_oop" handle. 2910 2911 // Set the thread field (a JavaThread *) of the 2912 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2913 2914 Handle thread_oop(Thread::current(), 2915 JNIHandles::resolve_non_null(jni_thread)); 2916 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 2917 "must be initialized"); 2918 set_threadObj(thread_oop()); 2919 java_lang_Thread::set_thread(thread_oop(), this); 2920 2921 if (prio == NoPriority) { 2922 prio = java_lang_Thread::priority(thread_oop()); 2923 assert(prio != NoPriority, "A valid priority should be present"); 2924 } 2925 2926 // Push the Java priority down to the native thread; needs Threads_lock 2927 Thread::set_priority(this, prio); 2928 2929 prepare_ext(); 2930 2931 // Add the new thread to the Threads list and set it in motion. 2932 // We must have threads lock in order to call Threads::add. 2933 // It is crucial that we do not block before the thread is 2934 // added to the Threads list for if a GC happens, then the java_thread oop 2935 // will not be visited by GC. 2936 Threads::add(this); 2937 } 2938 2939 oop JavaThread::current_park_blocker() { 2940 // Support for JSR-166 locks 2941 oop thread_oop = threadObj(); 2942 if (thread_oop != NULL && 2943 JDK_Version::current().supports_thread_park_blocker()) { 2944 return java_lang_Thread::park_blocker(thread_oop); 2945 } 2946 return NULL; 2947 } 2948 2949 2950 void JavaThread::print_stack_on(outputStream* st) { 2951 if (!has_last_Java_frame()) return; 2952 ResourceMark rm; 2953 HandleMark hm; 2954 2955 RegisterMap reg_map(this); 2956 vframe* start_vf = last_java_vframe(®_map); 2957 int count = 0; 2958 for (vframe* f = start_vf; f; f = f->sender()) { 2959 if (f->is_java_frame()) { 2960 javaVFrame* jvf = javaVFrame::cast(f); 2961 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 2962 2963 // Print out lock information 2964 if (JavaMonitorsInStackTrace) { 2965 jvf->print_lock_info_on(st, count); 2966 } 2967 } else { 2968 // Ignore non-Java frames 2969 } 2970 2971 // Bail-out case for too deep stacks 2972 count++; 2973 if (MaxJavaStackTraceDepth == count) return; 2974 } 2975 } 2976 2977 2978 // JVMTI PopFrame support 2979 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 2980 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 2981 if (in_bytes(size_in_bytes) != 0) { 2982 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 2983 _popframe_preserved_args_size = in_bytes(size_in_bytes); 2984 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 2985 } 2986 } 2987 2988 void* JavaThread::popframe_preserved_args() { 2989 return _popframe_preserved_args; 2990 } 2991 2992 ByteSize JavaThread::popframe_preserved_args_size() { 2993 return in_ByteSize(_popframe_preserved_args_size); 2994 } 2995 2996 WordSize JavaThread::popframe_preserved_args_size_in_words() { 2997 int sz = in_bytes(popframe_preserved_args_size()); 2998 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 2999 return in_WordSize(sz / wordSize); 3000 } 3001 3002 void JavaThread::popframe_free_preserved_args() { 3003 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3004 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3005 _popframe_preserved_args = NULL; 3006 _popframe_preserved_args_size = 0; 3007 } 3008 3009 #ifndef PRODUCT 3010 3011 void JavaThread::trace_frames() { 3012 tty->print_cr("[Describe stack]"); 3013 int frame_no = 1; 3014 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3015 tty->print(" %d. ", frame_no++); 3016 fst.current()->print_value_on(tty, this); 3017 tty->cr(); 3018 } 3019 } 3020 3021 class PrintAndVerifyOopClosure: public OopClosure { 3022 protected: 3023 template <class T> inline void do_oop_work(T* p) { 3024 oop obj = oopDesc::load_decode_heap_oop(p); 3025 if (obj == NULL) return; 3026 tty->print(INTPTR_FORMAT ": ", p); 3027 if (obj->is_oop_or_null()) { 3028 if (obj->is_objArray()) { 3029 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3030 } else { 3031 obj->print(); 3032 } 3033 } else { 3034 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3035 } 3036 tty->cr(); 3037 } 3038 public: 3039 virtual void do_oop(oop* p) { do_oop_work(p); } 3040 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3041 }; 3042 3043 3044 static void oops_print(frame* f, const RegisterMap *map) { 3045 PrintAndVerifyOopClosure print; 3046 f->print_value(); 3047 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3048 } 3049 3050 // Print our all the locations that contain oops and whether they are 3051 // valid or not. This useful when trying to find the oldest frame 3052 // where an oop has gone bad since the frame walk is from youngest to 3053 // oldest. 3054 void JavaThread::trace_oops() { 3055 tty->print_cr("[Trace oops]"); 3056 frames_do(oops_print); 3057 } 3058 3059 3060 #ifdef ASSERT 3061 // Print or validate the layout of stack frames 3062 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3063 ResourceMark rm; 3064 PRESERVE_EXCEPTION_MARK; 3065 FrameValues values; 3066 int frame_no = 0; 3067 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3068 fst.current()->describe(values, ++frame_no); 3069 if (depth == frame_no) break; 3070 } 3071 if (validate_only) { 3072 values.validate(); 3073 } else { 3074 tty->print_cr("[Describe stack layout]"); 3075 values.print(this); 3076 } 3077 } 3078 #endif 3079 3080 void JavaThread::trace_stack_from(vframe* start_vf) { 3081 ResourceMark rm; 3082 int vframe_no = 1; 3083 for (vframe* f = start_vf; f; f = f->sender()) { 3084 if (f->is_java_frame()) { 3085 javaVFrame::cast(f)->print_activation(vframe_no++); 3086 } else { 3087 f->print(); 3088 } 3089 if (vframe_no > StackPrintLimit) { 3090 tty->print_cr("...<more frames>..."); 3091 return; 3092 } 3093 } 3094 } 3095 3096 3097 void JavaThread::trace_stack() { 3098 if (!has_last_Java_frame()) return; 3099 ResourceMark rm; 3100 HandleMark hm; 3101 RegisterMap reg_map(this); 3102 trace_stack_from(last_java_vframe(®_map)); 3103 } 3104 3105 3106 #endif // PRODUCT 3107 3108 3109 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3110 assert(reg_map != NULL, "a map must be given"); 3111 frame f = last_frame(); 3112 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3113 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3114 } 3115 return NULL; 3116 } 3117 3118 3119 Klass* JavaThread::security_get_caller_class(int depth) { 3120 vframeStream vfst(this); 3121 vfst.security_get_caller_frame(depth); 3122 if (!vfst.at_end()) { 3123 return vfst.method()->method_holder(); 3124 } 3125 return NULL; 3126 } 3127 3128 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3129 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3130 CompileBroker::compiler_thread_loop(); 3131 } 3132 3133 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3134 NMethodSweeper::sweeper_loop(); 3135 } 3136 3137 // Create a CompilerThread 3138 CompilerThread::CompilerThread(CompileQueue* queue, 3139 CompilerCounters* counters) 3140 : JavaThread(&compiler_thread_entry) { 3141 _env = NULL; 3142 _log = NULL; 3143 _task = NULL; 3144 _queue = queue; 3145 _counters = counters; 3146 _buffer_blob = NULL; 3147 _compiler = NULL; 3148 3149 #ifndef PRODUCT 3150 _ideal_graph_printer = NULL; 3151 #endif 3152 } 3153 3154 // Create sweeper thread 3155 CodeCacheSweeperThread::CodeCacheSweeperThread() 3156 : JavaThread(&sweeper_thread_entry) { 3157 _scanned_nmethod = NULL; 3158 } 3159 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3160 JavaThread::oops_do(f, cld_f, cf); 3161 if (_scanned_nmethod != NULL && cf != NULL) { 3162 // Safepoints can occur when the sweeper is scanning an nmethod so 3163 // process it here to make sure it isn't unloaded in the middle of 3164 // a scan. 3165 cf->do_code_blob(_scanned_nmethod); 3166 } 3167 } 3168 3169 3170 // ======= Threads ======== 3171 3172 // The Threads class links together all active threads, and provides 3173 // operations over all threads. It is protected by its own Mutex 3174 // lock, which is also used in other contexts to protect thread 3175 // operations from having the thread being operated on from exiting 3176 // and going away unexpectedly (e.g., safepoint synchronization) 3177 3178 JavaThread* Threads::_thread_list = NULL; 3179 int Threads::_number_of_threads = 0; 3180 int Threads::_number_of_non_daemon_threads = 0; 3181 int Threads::_return_code = 0; 3182 int Threads::_thread_claim_parity = 0; 3183 size_t JavaThread::_stack_size_at_create = 0; 3184 #ifdef ASSERT 3185 bool Threads::_vm_complete = false; 3186 #endif 3187 3188 // All JavaThreads 3189 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3190 3191 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3192 void Threads::threads_do(ThreadClosure* tc) { 3193 assert_locked_or_safepoint(Threads_lock); 3194 // ALL_JAVA_THREADS iterates through all JavaThreads 3195 ALL_JAVA_THREADS(p) { 3196 tc->do_thread(p); 3197 } 3198 // Someday we could have a table or list of all non-JavaThreads. 3199 // For now, just manually iterate through them. 3200 tc->do_thread(VMThread::vm_thread()); 3201 Universe::heap()->gc_threads_do(tc); 3202 WatcherThread *wt = WatcherThread::watcher_thread(); 3203 // Strictly speaking, the following NULL check isn't sufficient to make sure 3204 // the data for WatcherThread is still valid upon being examined. However, 3205 // considering that WatchThread terminates when the VM is on the way to 3206 // exit at safepoint, the chance of the above is extremely small. The right 3207 // way to prevent termination of WatcherThread would be to acquire 3208 // Terminator_lock, but we can't do that without violating the lock rank 3209 // checking in some cases. 3210 if (wt != NULL) { 3211 tc->do_thread(wt); 3212 } 3213 3214 // If CompilerThreads ever become non-JavaThreads, add them here 3215 } 3216 3217 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3218 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3219 3220 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3221 create_vm_init_libraries(); 3222 } 3223 3224 initialize_class(vmSymbols::java_lang_String(), CHECK); 3225 3226 // Initialize java_lang.System (needed before creating the thread) 3227 initialize_class(vmSymbols::java_lang_System(), CHECK); 3228 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3229 Handle thread_group = create_initial_thread_group(CHECK); 3230 Universe::set_main_thread_group(thread_group()); 3231 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3232 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3233 main_thread->set_threadObj(thread_object); 3234 // Set thread status to running since main thread has 3235 // been started and running. 3236 java_lang_Thread::set_thread_status(thread_object, 3237 java_lang_Thread::RUNNABLE); 3238 3239 // The VM creates & returns objects of this class. Make sure it's initialized. 3240 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3241 3242 // The VM preresolves methods to these classes. Make sure that they get initialized 3243 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3244 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3245 call_initializeSystemClass(CHECK); 3246 3247 // get the Java runtime name after java.lang.System is initialized 3248 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3249 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3250 3251 // an instance of OutOfMemory exception has been allocated earlier 3252 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3253 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3254 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3255 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3256 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3257 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3258 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3259 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3260 } 3261 3262 void Threads::initialize_jsr292_core_classes(TRAPS) { 3263 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3264 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3265 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3266 } 3267 3268 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3269 extern void JDK_Version_init(); 3270 3271 // Check version 3272 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3273 3274 // Initialize the output stream module 3275 ostream_init(); 3276 3277 // Process java launcher properties. 3278 Arguments::process_sun_java_launcher_properties(args); 3279 3280 // Initialize the os module before using TLS 3281 os::init(); 3282 3283 // Initialize system properties. 3284 Arguments::init_system_properties(); 3285 3286 // So that JDK version can be used as a discriminator when parsing arguments 3287 JDK_Version_init(); 3288 3289 // Update/Initialize System properties after JDK version number is known 3290 Arguments::init_version_specific_system_properties(); 3291 3292 // Parse arguments 3293 jint parse_result = Arguments::parse(args); 3294 if (parse_result != JNI_OK) return parse_result; 3295 3296 os::init_before_ergo(); 3297 3298 jint ergo_result = Arguments::apply_ergo(); 3299 if (ergo_result != JNI_OK) return ergo_result; 3300 3301 if (PauseAtStartup) { 3302 os::pause(); 3303 } 3304 3305 HOTSPOT_VM_INIT_BEGIN(); 3306 3307 // Record VM creation timing statistics 3308 TraceVmCreationTime create_vm_timer; 3309 create_vm_timer.start(); 3310 3311 // Timing (must come after argument parsing) 3312 TraceTime timer("Create VM", TraceStartupTime); 3313 3314 // Initialize the os module after parsing the args 3315 jint os_init_2_result = os::init_2(); 3316 if (os_init_2_result != JNI_OK) return os_init_2_result; 3317 3318 jint adjust_after_os_result = Arguments::adjust_after_os(); 3319 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3320 3321 // initialize TLS 3322 ThreadLocalStorage::init(); 3323 3324 // Initialize output stream logging 3325 ostream_init_log(); 3326 3327 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3328 // Must be before create_vm_init_agents() 3329 if (Arguments::init_libraries_at_startup()) { 3330 convert_vm_init_libraries_to_agents(); 3331 } 3332 3333 // Launch -agentlib/-agentpath and converted -Xrun agents 3334 if (Arguments::init_agents_at_startup()) { 3335 create_vm_init_agents(); 3336 } 3337 3338 // Initialize Threads state 3339 _thread_list = NULL; 3340 _number_of_threads = 0; 3341 _number_of_non_daemon_threads = 0; 3342 3343 // Initialize global data structures and create system classes in heap 3344 vm_init_globals(); 3345 3346 // Attach the main thread to this os thread 3347 JavaThread* main_thread = new JavaThread(); 3348 main_thread->set_thread_state(_thread_in_vm); 3349 // must do this before set_active_handles and initialize_thread_local_storage 3350 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3351 // change the stack size recorded here to one based on the java thread 3352 // stacksize. This adjusted size is what is used to figure the placement 3353 // of the guard pages. 3354 main_thread->record_stack_base_and_size(); 3355 main_thread->initialize_thread_local_storage(); 3356 3357 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3358 3359 if (!main_thread->set_as_starting_thread()) { 3360 vm_shutdown_during_initialization( 3361 "Failed necessary internal allocation. Out of swap space"); 3362 delete main_thread; 3363 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3364 return JNI_ENOMEM; 3365 } 3366 3367 // Enable guard page *after* os::create_main_thread(), otherwise it would 3368 // crash Linux VM, see notes in os_linux.cpp. 3369 main_thread->create_stack_guard_pages(); 3370 3371 // Initialize Java-Level synchronization subsystem 3372 ObjectMonitor::Initialize(); 3373 3374 // Initialize global modules 3375 jint status = init_globals(); 3376 if (status != JNI_OK) { 3377 delete main_thread; 3378 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3379 return status; 3380 } 3381 3382 // Should be done after the heap is fully created 3383 main_thread->cache_global_variables(); 3384 3385 HandleMark hm; 3386 3387 { MutexLocker mu(Threads_lock); 3388 Threads::add(main_thread); 3389 } 3390 3391 // Any JVMTI raw monitors entered in onload will transition into 3392 // real raw monitor. VM is setup enough here for raw monitor enter. 3393 JvmtiExport::transition_pending_onload_raw_monitors(); 3394 3395 // Create the VMThread 3396 { TraceTime timer("Start VMThread", TraceStartupTime); 3397 VMThread::create(); 3398 Thread* vmthread = VMThread::vm_thread(); 3399 3400 if (!os::create_thread(vmthread, os::vm_thread)) { 3401 vm_exit_during_initialization("Cannot create VM thread. " 3402 "Out of system resources."); 3403 } 3404 3405 // Wait for the VM thread to become ready, and VMThread::run to initialize 3406 // Monitors can have spurious returns, must always check another state flag 3407 { 3408 MutexLocker ml(Notify_lock); 3409 os::start_thread(vmthread); 3410 while (vmthread->active_handles() == NULL) { 3411 Notify_lock->wait(); 3412 } 3413 } 3414 } 3415 3416 assert(Universe::is_fully_initialized(), "not initialized"); 3417 if (VerifyDuringStartup) { 3418 // Make sure we're starting with a clean slate. 3419 VM_Verify verify_op; 3420 VMThread::execute(&verify_op); 3421 } 3422 3423 Thread* THREAD = Thread::current(); 3424 3425 // At this point, the Universe is initialized, but we have not executed 3426 // any byte code. Now is a good time (the only time) to dump out the 3427 // internal state of the JVM for sharing. 3428 if (DumpSharedSpaces) { 3429 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3430 ShouldNotReachHere(); 3431 } 3432 3433 // Always call even when there are not JVMTI environments yet, since environments 3434 // may be attached late and JVMTI must track phases of VM execution 3435 JvmtiExport::enter_start_phase(); 3436 3437 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3438 JvmtiExport::post_vm_start(); 3439 3440 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3441 3442 // We need this for ClassDataSharing - the initial vm.info property is set 3443 // with the default value of CDS "sharing" which may be reset through 3444 // command line options. 3445 reset_vm_info_property(CHECK_JNI_ERR); 3446 3447 quicken_jni_functions(); 3448 3449 // Must be run after init_ft which initializes ft_enabled 3450 if (TRACE_INITIALIZE() != JNI_OK) { 3451 vm_exit_during_initialization("Failed to initialize tracing backend"); 3452 } 3453 3454 // Set flag that basic initialization has completed. Used by exceptions and various 3455 // debug stuff, that does not work until all basic classes have been initialized. 3456 set_init_completed(); 3457 3458 Metaspace::post_initialize(); 3459 3460 HOTSPOT_VM_INIT_END(); 3461 3462 // record VM initialization completion time 3463 #if INCLUDE_MANAGEMENT 3464 Management::record_vm_init_completed(); 3465 #endif // INCLUDE_MANAGEMENT 3466 3467 // Compute system loader. Note that this has to occur after set_init_completed, since 3468 // valid exceptions may be thrown in the process. 3469 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3470 // set_init_completed has just been called, causing exceptions not to be shortcut 3471 // anymore. We call vm_exit_during_initialization directly instead. 3472 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR); 3473 3474 #if INCLUDE_ALL_GCS 3475 // Support for ConcurrentMarkSweep. This should be cleaned up 3476 // and better encapsulated. The ugly nested if test would go away 3477 // once things are properly refactored. XXX YSR 3478 if (UseConcMarkSweepGC || UseG1GC) { 3479 if (UseConcMarkSweepGC) { 3480 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3481 } else { 3482 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3483 } 3484 } 3485 #endif // INCLUDE_ALL_GCS 3486 3487 // Always call even when there are not JVMTI environments yet, since environments 3488 // may be attached late and JVMTI must track phases of VM execution 3489 JvmtiExport::enter_live_phase(); 3490 3491 // Signal Dispatcher needs to be started before VMInit event is posted 3492 os::signal_init(); 3493 3494 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3495 if (!DisableAttachMechanism) { 3496 AttachListener::vm_start(); 3497 if (StartAttachListener || AttachListener::init_at_startup()) { 3498 AttachListener::init(); 3499 } 3500 } 3501 3502 // Launch -Xrun agents 3503 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3504 // back-end can launch with -Xdebug -Xrunjdwp. 3505 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3506 create_vm_init_libraries(); 3507 } 3508 3509 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3510 JvmtiExport::post_vm_initialized(); 3511 3512 if (TRACE_START() != JNI_OK) { 3513 vm_exit_during_initialization("Failed to start tracing backend."); 3514 } 3515 3516 if (CleanChunkPoolAsync) { 3517 Chunk::start_chunk_pool_cleaner_task(); 3518 } 3519 3520 // initialize compiler(s) 3521 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3522 CompileBroker::compilation_init(); 3523 #endif 3524 3525 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3526 // It is done after compilers are initialized, because otherwise compilations of 3527 // signature polymorphic MH intrinsics can be missed 3528 // (see SystemDictionary::find_method_handle_intrinsic). 3529 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3530 3531 #if INCLUDE_MANAGEMENT 3532 Management::initialize(THREAD); 3533 3534 if (HAS_PENDING_EXCEPTION) { 3535 // management agent fails to start possibly due to 3536 // configuration problem and is responsible for printing 3537 // stack trace if appropriate. Simply exit VM. 3538 vm_exit(1); 3539 } 3540 #endif // INCLUDE_MANAGEMENT 3541 3542 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3543 if (MemProfiling) MemProfiler::engage(); 3544 StatSampler::engage(); 3545 if (CheckJNICalls) JniPeriodicChecker::engage(); 3546 3547 BiasedLocking::init(); 3548 3549 #if INCLUDE_RTM_OPT 3550 RTMLockingCounters::init(); 3551 #endif 3552 3553 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3554 call_postVMInitHook(THREAD); 3555 // The Java side of PostVMInitHook.run must deal with all 3556 // exceptions and provide means of diagnosis. 3557 if (HAS_PENDING_EXCEPTION) { 3558 CLEAR_PENDING_EXCEPTION; 3559 } 3560 } 3561 3562 { 3563 MutexLocker ml(PeriodicTask_lock); 3564 // Make sure the WatcherThread can be started by WatcherThread::start() 3565 // or by dynamic enrollment. 3566 WatcherThread::make_startable(); 3567 // Start up the WatcherThread if there are any periodic tasks 3568 // NOTE: All PeriodicTasks should be registered by now. If they 3569 // aren't, late joiners might appear to start slowly (we might 3570 // take a while to process their first tick). 3571 if (PeriodicTask::num_tasks() > 0) { 3572 WatcherThread::start(); 3573 } 3574 } 3575 3576 create_vm_timer.end(); 3577 #ifdef ASSERT 3578 _vm_complete = true; 3579 #endif 3580 return JNI_OK; 3581 } 3582 3583 // type for the Agent_OnLoad and JVM_OnLoad entry points 3584 extern "C" { 3585 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3586 } 3587 // Find a command line agent library and return its entry point for 3588 // -agentlib: -agentpath: -Xrun 3589 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3590 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 3591 const char *on_load_symbols[], 3592 size_t num_symbol_entries) { 3593 OnLoadEntry_t on_load_entry = NULL; 3594 void *library = NULL; 3595 3596 if (!agent->valid()) { 3597 char buffer[JVM_MAXPATHLEN]; 3598 char ebuf[1024] = ""; 3599 const char *name = agent->name(); 3600 const char *msg = "Could not find agent library "; 3601 3602 // First check to see if agent is statically linked into executable 3603 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3604 library = agent->os_lib(); 3605 } else if (agent->is_absolute_path()) { 3606 library = os::dll_load(name, ebuf, sizeof ebuf); 3607 if (library == NULL) { 3608 const char *sub_msg = " in absolute path, with error: "; 3609 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3610 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3611 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3612 // If we can't find the agent, exit. 3613 vm_exit_during_initialization(buf, NULL); 3614 FREE_C_HEAP_ARRAY(char, buf); 3615 } 3616 } else { 3617 // Try to load the agent from the standard dll directory 3618 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3619 name)) { 3620 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3621 } 3622 if (library == NULL) { // Try the local directory 3623 char ns[1] = {0}; 3624 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3625 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3626 } 3627 if (library == NULL) { 3628 const char *sub_msg = " on the library path, with error: "; 3629 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3630 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3631 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3632 // If we can't find the agent, exit. 3633 vm_exit_during_initialization(buf, NULL); 3634 FREE_C_HEAP_ARRAY(char, buf); 3635 } 3636 } 3637 } 3638 agent->set_os_lib(library); 3639 agent->set_valid(); 3640 } 3641 3642 // Find the OnLoad function. 3643 on_load_entry = 3644 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3645 false, 3646 on_load_symbols, 3647 num_symbol_entries)); 3648 return on_load_entry; 3649 } 3650 3651 // Find the JVM_OnLoad entry point 3652 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3653 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3654 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3655 } 3656 3657 // Find the Agent_OnLoad entry point 3658 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3659 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3660 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3661 } 3662 3663 // For backwards compatibility with -Xrun 3664 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3665 // treated like -agentpath: 3666 // Must be called before agent libraries are created 3667 void Threads::convert_vm_init_libraries_to_agents() { 3668 AgentLibrary* agent; 3669 AgentLibrary* next; 3670 3671 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3672 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3673 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3674 3675 // If there is an JVM_OnLoad function it will get called later, 3676 // otherwise see if there is an Agent_OnLoad 3677 if (on_load_entry == NULL) { 3678 on_load_entry = lookup_agent_on_load(agent); 3679 if (on_load_entry != NULL) { 3680 // switch it to the agent list -- so that Agent_OnLoad will be called, 3681 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3682 Arguments::convert_library_to_agent(agent); 3683 } else { 3684 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3685 } 3686 } 3687 } 3688 } 3689 3690 // Create agents for -agentlib: -agentpath: and converted -Xrun 3691 // Invokes Agent_OnLoad 3692 // Called very early -- before JavaThreads exist 3693 void Threads::create_vm_init_agents() { 3694 extern struct JavaVM_ main_vm; 3695 AgentLibrary* agent; 3696 3697 JvmtiExport::enter_onload_phase(); 3698 3699 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3700 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3701 3702 if (on_load_entry != NULL) { 3703 // Invoke the Agent_OnLoad function 3704 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3705 if (err != JNI_OK) { 3706 vm_exit_during_initialization("agent library failed to init", agent->name()); 3707 } 3708 } else { 3709 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3710 } 3711 } 3712 JvmtiExport::enter_primordial_phase(); 3713 } 3714 3715 extern "C" { 3716 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3717 } 3718 3719 void Threads::shutdown_vm_agents() { 3720 // Send any Agent_OnUnload notifications 3721 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3722 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3723 extern struct JavaVM_ main_vm; 3724 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3725 3726 // Find the Agent_OnUnload function. 3727 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3728 os::find_agent_function(agent, 3729 false, 3730 on_unload_symbols, 3731 num_symbol_entries)); 3732 3733 // Invoke the Agent_OnUnload function 3734 if (unload_entry != NULL) { 3735 JavaThread* thread = JavaThread::current(); 3736 ThreadToNativeFromVM ttn(thread); 3737 HandleMark hm(thread); 3738 (*unload_entry)(&main_vm); 3739 } 3740 } 3741 } 3742 3743 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3744 // Invokes JVM_OnLoad 3745 void Threads::create_vm_init_libraries() { 3746 extern struct JavaVM_ main_vm; 3747 AgentLibrary* agent; 3748 3749 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3750 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3751 3752 if (on_load_entry != NULL) { 3753 // Invoke the JVM_OnLoad function 3754 JavaThread* thread = JavaThread::current(); 3755 ThreadToNativeFromVM ttn(thread); 3756 HandleMark hm(thread); 3757 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3758 if (err != JNI_OK) { 3759 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3760 } 3761 } else { 3762 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3763 } 3764 } 3765 } 3766 3767 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3768 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3769 3770 JavaThread* java_thread = NULL; 3771 // Sequential search for now. Need to do better optimization later. 3772 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3773 oop tobj = thread->threadObj(); 3774 if (!thread->is_exiting() && 3775 tobj != NULL && 3776 java_tid == java_lang_Thread::thread_id(tobj)) { 3777 java_thread = thread; 3778 break; 3779 } 3780 } 3781 return java_thread; 3782 } 3783 3784 3785 // Last thread running calls java.lang.Shutdown.shutdown() 3786 void JavaThread::invoke_shutdown_hooks() { 3787 HandleMark hm(this); 3788 3789 // We could get here with a pending exception, if so clear it now. 3790 if (this->has_pending_exception()) { 3791 this->clear_pending_exception(); 3792 } 3793 3794 EXCEPTION_MARK; 3795 Klass* k = 3796 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3797 THREAD); 3798 if (k != NULL) { 3799 // SystemDictionary::resolve_or_null will return null if there was 3800 // an exception. If we cannot load the Shutdown class, just don't 3801 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3802 // and finalizers (if runFinalizersOnExit is set) won't be run. 3803 // Note that if a shutdown hook was registered or runFinalizersOnExit 3804 // was called, the Shutdown class would have already been loaded 3805 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3806 instanceKlassHandle shutdown_klass (THREAD, k); 3807 JavaValue result(T_VOID); 3808 JavaCalls::call_static(&result, 3809 shutdown_klass, 3810 vmSymbols::shutdown_method_name(), 3811 vmSymbols::void_method_signature(), 3812 THREAD); 3813 } 3814 CLEAR_PENDING_EXCEPTION; 3815 } 3816 3817 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3818 // the program falls off the end of main(). Another VM exit path is through 3819 // vm_exit() when the program calls System.exit() to return a value or when 3820 // there is a serious error in VM. The two shutdown paths are not exactly 3821 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3822 // and VM_Exit op at VM level. 3823 // 3824 // Shutdown sequence: 3825 // + Shutdown native memory tracking if it is on 3826 // + Wait until we are the last non-daemon thread to execute 3827 // <-- every thing is still working at this moment --> 3828 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3829 // shutdown hooks, run finalizers if finalization-on-exit 3830 // + Call before_exit(), prepare for VM exit 3831 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3832 // currently the only user of this mechanism is File.deleteOnExit()) 3833 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3834 // post thread end and vm death events to JVMTI, 3835 // stop signal thread 3836 // + Call JavaThread::exit(), it will: 3837 // > release JNI handle blocks, remove stack guard pages 3838 // > remove this thread from Threads list 3839 // <-- no more Java code from this thread after this point --> 3840 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3841 // the compiler threads at safepoint 3842 // <-- do not use anything that could get blocked by Safepoint --> 3843 // + Disable tracing at JNI/JVM barriers 3844 // + Set _vm_exited flag for threads that are still running native code 3845 // + Delete this thread 3846 // + Call exit_globals() 3847 // > deletes tty 3848 // > deletes PerfMemory resources 3849 // + Return to caller 3850 3851 bool Threads::destroy_vm() { 3852 JavaThread* thread = JavaThread::current(); 3853 3854 #ifdef ASSERT 3855 _vm_complete = false; 3856 #endif 3857 // Wait until we are the last non-daemon thread to execute 3858 { MutexLocker nu(Threads_lock); 3859 while (Threads::number_of_non_daemon_threads() > 1) 3860 // This wait should make safepoint checks, wait without a timeout, 3861 // and wait as a suspend-equivalent condition. 3862 // 3863 // Note: If the FlatProfiler is running and this thread is waiting 3864 // for another non-daemon thread to finish, then the FlatProfiler 3865 // is waiting for the external suspend request on this thread to 3866 // complete. wait_for_ext_suspend_completion() will eventually 3867 // timeout, but that takes time. Making this wait a suspend- 3868 // equivalent condition solves that timeout problem. 3869 // 3870 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3871 Mutex::_as_suspend_equivalent_flag); 3872 } 3873 3874 // Hang forever on exit if we are reporting an error. 3875 if (ShowMessageBoxOnError && is_error_reported()) { 3876 os::infinite_sleep(); 3877 } 3878 os::wait_for_keypress_at_exit(); 3879 3880 // run Java level shutdown hooks 3881 thread->invoke_shutdown_hooks(); 3882 3883 before_exit(thread); 3884 3885 thread->exit(true); 3886 3887 // Stop VM thread. 3888 { 3889 // 4945125 The vm thread comes to a safepoint during exit. 3890 // GC vm_operations can get caught at the safepoint, and the 3891 // heap is unparseable if they are caught. Grab the Heap_lock 3892 // to prevent this. The GC vm_operations will not be able to 3893 // queue until after the vm thread is dead. After this point, 3894 // we'll never emerge out of the safepoint before the VM exits. 3895 3896 MutexLocker ml(Heap_lock); 3897 3898 VMThread::wait_for_vm_thread_exit(); 3899 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3900 VMThread::destroy(); 3901 } 3902 3903 // clean up ideal graph printers 3904 #if defined(COMPILER2) && !defined(PRODUCT) 3905 IdealGraphPrinter::clean_up(); 3906 #endif 3907 3908 // Now, all Java threads are gone except daemon threads. Daemon threads 3909 // running Java code or in VM are stopped by the Safepoint. However, 3910 // daemon threads executing native code are still running. But they 3911 // will be stopped at native=>Java/VM barriers. Note that we can't 3912 // simply kill or suspend them, as it is inherently deadlock-prone. 3913 3914 #ifndef PRODUCT 3915 // disable function tracing at JNI/JVM barriers 3916 TraceJNICalls = false; 3917 TraceJVMCalls = false; 3918 TraceRuntimeCalls = false; 3919 #endif 3920 3921 VM_Exit::set_vm_exited(); 3922 3923 notify_vm_shutdown(); 3924 3925 delete thread; 3926 3927 // exit_globals() will delete tty 3928 exit_globals(); 3929 3930 return true; 3931 } 3932 3933 3934 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 3935 if (version == JNI_VERSION_1_1) return JNI_TRUE; 3936 return is_supported_jni_version(version); 3937 } 3938 3939 3940 jboolean Threads::is_supported_jni_version(jint version) { 3941 if (version == JNI_VERSION_1_2) return JNI_TRUE; 3942 if (version == JNI_VERSION_1_4) return JNI_TRUE; 3943 if (version == JNI_VERSION_1_6) return JNI_TRUE; 3944 if (version == JNI_VERSION_1_8) return JNI_TRUE; 3945 return JNI_FALSE; 3946 } 3947 3948 3949 void Threads::add(JavaThread* p, bool force_daemon) { 3950 // The threads lock must be owned at this point 3951 assert_locked_or_safepoint(Threads_lock); 3952 3953 // See the comment for this method in thread.hpp for its purpose and 3954 // why it is called here. 3955 p->initialize_queues(); 3956 p->set_next(_thread_list); 3957 _thread_list = p; 3958 _number_of_threads++; 3959 oop threadObj = p->threadObj(); 3960 bool daemon = true; 3961 // Bootstrapping problem: threadObj can be null for initial 3962 // JavaThread (or for threads attached via JNI) 3963 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 3964 _number_of_non_daemon_threads++; 3965 daemon = false; 3966 } 3967 3968 ThreadService::add_thread(p, daemon); 3969 3970 // Possible GC point. 3971 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 3972 } 3973 3974 void Threads::remove(JavaThread* p) { 3975 // Extra scope needed for Thread_lock, so we can check 3976 // that we do not remove thread without safepoint code notice 3977 { MutexLocker ml(Threads_lock); 3978 3979 assert(includes(p), "p must be present"); 3980 3981 JavaThread* current = _thread_list; 3982 JavaThread* prev = NULL; 3983 3984 while (current != p) { 3985 prev = current; 3986 current = current->next(); 3987 } 3988 3989 if (prev) { 3990 prev->set_next(current->next()); 3991 } else { 3992 _thread_list = p->next(); 3993 } 3994 _number_of_threads--; 3995 oop threadObj = p->threadObj(); 3996 bool daemon = true; 3997 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 3998 _number_of_non_daemon_threads--; 3999 daemon = false; 4000 4001 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4002 // on destroy_vm will wake up. 4003 if (number_of_non_daemon_threads() == 1) { 4004 Threads_lock->notify_all(); 4005 } 4006 } 4007 ThreadService::remove_thread(p, daemon); 4008 4009 // Make sure that safepoint code disregard this thread. This is needed since 4010 // the thread might mess around with locks after this point. This can cause it 4011 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4012 // of this thread since it is removed from the queue. 4013 p->set_terminated_value(); 4014 } // unlock Threads_lock 4015 4016 // Since Events::log uses a lock, we grab it outside the Threads_lock 4017 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4018 } 4019 4020 // Threads_lock must be held when this is called (or must be called during a safepoint) 4021 bool Threads::includes(JavaThread* p) { 4022 assert(Threads_lock->is_locked(), "sanity check"); 4023 ALL_JAVA_THREADS(q) { 4024 if (q == p) { 4025 return true; 4026 } 4027 } 4028 return false; 4029 } 4030 4031 // Operations on the Threads list for GC. These are not explicitly locked, 4032 // but the garbage collector must provide a safe context for them to run. 4033 // In particular, these things should never be called when the Threads_lock 4034 // is held by some other thread. (Note: the Safepoint abstraction also 4035 // uses the Threads_lock to guarantee this property. It also makes sure that 4036 // all threads gets blocked when exiting or starting). 4037 4038 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4039 ALL_JAVA_THREADS(p) { 4040 p->oops_do(f, cld_f, cf); 4041 } 4042 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4043 } 4044 4045 void Threads::change_thread_claim_parity() { 4046 // Set the new claim parity. 4047 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2, 4048 "Not in range."); 4049 _thread_claim_parity++; 4050 if (_thread_claim_parity == 3) _thread_claim_parity = 1; 4051 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2, 4052 "Not in range."); 4053 } 4054 4055 #ifndef PRODUCT 4056 void Threads::assert_all_threads_claimed() { 4057 ALL_JAVA_THREADS(p) { 4058 const int thread_parity = p->oops_do_parity(); 4059 assert((thread_parity == _thread_claim_parity), 4060 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity)); 4061 } 4062 } 4063 #endif // PRODUCT 4064 4065 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4066 int cp = Threads::thread_claim_parity(); 4067 ALL_JAVA_THREADS(p) { 4068 if (p->claim_oops_do(is_par, cp)) { 4069 p->oops_do(f, cld_f, cf); 4070 } 4071 } 4072 VMThread* vmt = VMThread::vm_thread(); 4073 if (vmt->claim_oops_do(is_par, cp)) { 4074 vmt->oops_do(f, cld_f, cf); 4075 } 4076 } 4077 4078 #if INCLUDE_ALL_GCS 4079 // Used by ParallelScavenge 4080 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4081 ALL_JAVA_THREADS(p) { 4082 q->enqueue(new ThreadRootsTask(p)); 4083 } 4084 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4085 } 4086 4087 // Used by Parallel Old 4088 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4089 ALL_JAVA_THREADS(p) { 4090 q->enqueue(new ThreadRootsMarkingTask(p)); 4091 } 4092 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4093 } 4094 #endif // INCLUDE_ALL_GCS 4095 4096 void Threads::nmethods_do(CodeBlobClosure* cf) { 4097 ALL_JAVA_THREADS(p) { 4098 p->nmethods_do(cf); 4099 } 4100 VMThread::vm_thread()->nmethods_do(cf); 4101 } 4102 4103 void Threads::metadata_do(void f(Metadata*)) { 4104 ALL_JAVA_THREADS(p) { 4105 p->metadata_do(f); 4106 } 4107 } 4108 4109 class ThreadHandlesClosure : public ThreadClosure { 4110 void (*_f)(Metadata*); 4111 public: 4112 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4113 virtual void do_thread(Thread* thread) { 4114 thread->metadata_handles_do(_f); 4115 } 4116 }; 4117 4118 void Threads::metadata_handles_do(void f(Metadata*)) { 4119 // Only walk the Handles in Thread. 4120 ThreadHandlesClosure handles_closure(f); 4121 threads_do(&handles_closure); 4122 } 4123 4124 void Threads::deoptimized_wrt_marked_nmethods() { 4125 ALL_JAVA_THREADS(p) { 4126 p->deoptimized_wrt_marked_nmethods(); 4127 } 4128 } 4129 4130 4131 // Get count Java threads that are waiting to enter the specified monitor. 4132 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4133 address monitor, 4134 bool doLock) { 4135 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4136 "must grab Threads_lock or be at safepoint"); 4137 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4138 4139 int i = 0; 4140 { 4141 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4142 ALL_JAVA_THREADS(p) { 4143 if (p->is_Compiler_thread()) continue; 4144 4145 address pending = (address)p->current_pending_monitor(); 4146 if (pending == monitor) { // found a match 4147 if (i < count) result->append(p); // save the first count matches 4148 i++; 4149 } 4150 } 4151 } 4152 return result; 4153 } 4154 4155 4156 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, 4157 bool doLock) { 4158 assert(doLock || 4159 Threads_lock->owned_by_self() || 4160 SafepointSynchronize::is_at_safepoint(), 4161 "must grab Threads_lock or be at safepoint"); 4162 4163 // NULL owner means not locked so we can skip the search 4164 if (owner == NULL) return NULL; 4165 4166 { 4167 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4168 ALL_JAVA_THREADS(p) { 4169 // first, see if owner is the address of a Java thread 4170 if (owner == (address)p) return p; 4171 } 4172 } 4173 // Cannot assert on lack of success here since this function may be 4174 // used by code that is trying to report useful problem information 4175 // like deadlock detection. 4176 if (UseHeavyMonitors) return NULL; 4177 4178 // If we didn't find a matching Java thread and we didn't force use of 4179 // heavyweight monitors, then the owner is the stack address of the 4180 // Lock Word in the owning Java thread's stack. 4181 // 4182 JavaThread* the_owner = NULL; 4183 { 4184 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4185 ALL_JAVA_THREADS(q) { 4186 if (q->is_lock_owned(owner)) { 4187 the_owner = q; 4188 break; 4189 } 4190 } 4191 } 4192 // cannot assert on lack of success here; see above comment 4193 return the_owner; 4194 } 4195 4196 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4197 void Threads::print_on(outputStream* st, bool print_stacks, 4198 bool internal_format, bool print_concurrent_locks) { 4199 char buf[32]; 4200 st->print_cr("%s", os::local_time_string(buf, sizeof(buf))); 4201 4202 st->print_cr("Full thread dump %s (%s %s):", 4203 Abstract_VM_Version::vm_name(), 4204 Abstract_VM_Version::vm_release(), 4205 Abstract_VM_Version::vm_info_string()); 4206 st->cr(); 4207 4208 #if INCLUDE_ALL_GCS 4209 // Dump concurrent locks 4210 ConcurrentLocksDump concurrent_locks; 4211 if (print_concurrent_locks) { 4212 concurrent_locks.dump_at_safepoint(); 4213 } 4214 #endif // INCLUDE_ALL_GCS 4215 4216 ALL_JAVA_THREADS(p) { 4217 ResourceMark rm; 4218 p->print_on(st); 4219 if (print_stacks) { 4220 if (internal_format) { 4221 p->trace_stack(); 4222 } else { 4223 p->print_stack_on(st); 4224 } 4225 } 4226 st->cr(); 4227 #if INCLUDE_ALL_GCS 4228 if (print_concurrent_locks) { 4229 concurrent_locks.print_locks_on(p, st); 4230 } 4231 #endif // INCLUDE_ALL_GCS 4232 } 4233 4234 VMThread::vm_thread()->print_on(st); 4235 st->cr(); 4236 Universe::heap()->print_gc_threads_on(st); 4237 WatcherThread* wt = WatcherThread::watcher_thread(); 4238 if (wt != NULL) { 4239 wt->print_on(st); 4240 st->cr(); 4241 } 4242 CompileBroker::print_compiler_threads_on(st); 4243 st->flush(); 4244 } 4245 4246 // Threads::print_on_error() is called by fatal error handler. It's possible 4247 // that VM is not at safepoint and/or current thread is inside signal handler. 4248 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4249 // memory (even in resource area), it might deadlock the error handler. 4250 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4251 int buflen) { 4252 bool found_current = false; 4253 st->print_cr("Java Threads: ( => current thread )"); 4254 ALL_JAVA_THREADS(thread) { 4255 bool is_current = (current == thread); 4256 found_current = found_current || is_current; 4257 4258 st->print("%s", is_current ? "=>" : " "); 4259 4260 st->print(PTR_FORMAT, thread); 4261 st->print(" "); 4262 thread->print_on_error(st, buf, buflen); 4263 st->cr(); 4264 } 4265 st->cr(); 4266 4267 st->print_cr("Other Threads:"); 4268 if (VMThread::vm_thread()) { 4269 bool is_current = (current == VMThread::vm_thread()); 4270 found_current = found_current || is_current; 4271 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4272 4273 st->print(PTR_FORMAT, VMThread::vm_thread()); 4274 st->print(" "); 4275 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4276 st->cr(); 4277 } 4278 WatcherThread* wt = WatcherThread::watcher_thread(); 4279 if (wt != NULL) { 4280 bool is_current = (current == wt); 4281 found_current = found_current || is_current; 4282 st->print("%s", is_current ? "=>" : " "); 4283 4284 st->print(PTR_FORMAT, wt); 4285 st->print(" "); 4286 wt->print_on_error(st, buf, buflen); 4287 st->cr(); 4288 } 4289 if (!found_current) { 4290 st->cr(); 4291 st->print("=>" PTR_FORMAT " (exited) ", current); 4292 current->print_on_error(st, buf, buflen); 4293 st->cr(); 4294 } 4295 } 4296 4297 // Internal SpinLock and Mutex 4298 // Based on ParkEvent 4299 4300 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4301 // 4302 // We employ SpinLocks _only for low-contention, fixed-length 4303 // short-duration critical sections where we're concerned 4304 // about native mutex_t or HotSpot Mutex:: latency. 4305 // The mux construct provides a spin-then-block mutual exclusion 4306 // mechanism. 4307 // 4308 // Testing has shown that contention on the ListLock guarding gFreeList 4309 // is common. If we implement ListLock as a simple SpinLock it's common 4310 // for the JVM to devolve to yielding with little progress. This is true 4311 // despite the fact that the critical sections protected by ListLock are 4312 // extremely short. 4313 // 4314 // TODO-FIXME: ListLock should be of type SpinLock. 4315 // We should make this a 1st-class type, integrated into the lock 4316 // hierarchy as leaf-locks. Critically, the SpinLock structure 4317 // should have sufficient padding to avoid false-sharing and excessive 4318 // cache-coherency traffic. 4319 4320 4321 typedef volatile int SpinLockT; 4322 4323 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4324 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4325 return; // normal fast-path return 4326 } 4327 4328 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4329 TEVENT(SpinAcquire - ctx); 4330 int ctr = 0; 4331 int Yields = 0; 4332 for (;;) { 4333 while (*adr != 0) { 4334 ++ctr; 4335 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4336 if (Yields > 5) { 4337 os::naked_short_sleep(1); 4338 } else { 4339 os::naked_yield(); 4340 ++Yields; 4341 } 4342 } else { 4343 SpinPause(); 4344 } 4345 } 4346 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4347 } 4348 } 4349 4350 void Thread::SpinRelease(volatile int * adr) { 4351 assert(*adr != 0, "invariant"); 4352 OrderAccess::fence(); // guarantee at least release consistency. 4353 // Roach-motel semantics. 4354 // It's safe if subsequent LDs and STs float "up" into the critical section, 4355 // but prior LDs and STs within the critical section can't be allowed 4356 // to reorder or float past the ST that releases the lock. 4357 // Loads and stores in the critical section - which appear in program 4358 // order before the store that releases the lock - must also appear 4359 // before the store that releases the lock in memory visibility order. 4360 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4361 // the ST of 0 into the lock-word which releases the lock, so fence 4362 // more than covers this on all platforms. 4363 *adr = 0; 4364 } 4365 4366 // muxAcquire and muxRelease: 4367 // 4368 // * muxAcquire and muxRelease support a single-word lock-word construct. 4369 // The LSB of the word is set IFF the lock is held. 4370 // The remainder of the word points to the head of a singly-linked list 4371 // of threads blocked on the lock. 4372 // 4373 // * The current implementation of muxAcquire-muxRelease uses its own 4374 // dedicated Thread._MuxEvent instance. If we're interested in 4375 // minimizing the peak number of extant ParkEvent instances then 4376 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4377 // as certain invariants were satisfied. Specifically, care would need 4378 // to be taken with regards to consuming unpark() "permits". 4379 // A safe rule of thumb is that a thread would never call muxAcquire() 4380 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4381 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4382 // consume an unpark() permit intended for monitorenter, for instance. 4383 // One way around this would be to widen the restricted-range semaphore 4384 // implemented in park(). Another alternative would be to provide 4385 // multiple instances of the PlatformEvent() for each thread. One 4386 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4387 // 4388 // * Usage: 4389 // -- Only as leaf locks 4390 // -- for short-term locking only as muxAcquire does not perform 4391 // thread state transitions. 4392 // 4393 // Alternatives: 4394 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4395 // but with parking or spin-then-park instead of pure spinning. 4396 // * Use Taura-Oyama-Yonenzawa locks. 4397 // * It's possible to construct a 1-0 lock if we encode the lockword as 4398 // (List,LockByte). Acquire will CAS the full lockword while Release 4399 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4400 // acquiring threads use timers (ParkTimed) to detect and recover from 4401 // the stranding window. Thread/Node structures must be aligned on 256-byte 4402 // boundaries by using placement-new. 4403 // * Augment MCS with advisory back-link fields maintained with CAS(). 4404 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4405 // The validity of the backlinks must be ratified before we trust the value. 4406 // If the backlinks are invalid the exiting thread must back-track through the 4407 // the forward links, which are always trustworthy. 4408 // * Add a successor indication. The LockWord is currently encoded as 4409 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4410 // to provide the usual futile-wakeup optimization. 4411 // See RTStt for details. 4412 // * Consider schedctl.sc_nopreempt to cover the critical section. 4413 // 4414 4415 4416 typedef volatile intptr_t MutexT; // Mux Lock-word 4417 enum MuxBits { LOCKBIT = 1 }; 4418 4419 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4420 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4421 if (w == 0) return; 4422 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4423 return; 4424 } 4425 4426 TEVENT(muxAcquire - Contention); 4427 ParkEvent * const Self = Thread::current()->_MuxEvent; 4428 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4429 for (;;) { 4430 int its = (os::is_MP() ? 100 : 0) + 1; 4431 4432 // Optional spin phase: spin-then-park strategy 4433 while (--its >= 0) { 4434 w = *Lock; 4435 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4436 return; 4437 } 4438 } 4439 4440 Self->reset(); 4441 Self->OnList = intptr_t(Lock); 4442 // The following fence() isn't _strictly necessary as the subsequent 4443 // CAS() both serializes execution and ratifies the fetched *Lock value. 4444 OrderAccess::fence(); 4445 for (;;) { 4446 w = *Lock; 4447 if ((w & LOCKBIT) == 0) { 4448 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4449 Self->OnList = 0; // hygiene - allows stronger asserts 4450 return; 4451 } 4452 continue; // Interference -- *Lock changed -- Just retry 4453 } 4454 assert(w & LOCKBIT, "invariant"); 4455 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4456 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4457 } 4458 4459 while (Self->OnList != 0) { 4460 Self->park(); 4461 } 4462 } 4463 } 4464 4465 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4466 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4467 if (w == 0) return; 4468 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4469 return; 4470 } 4471 4472 TEVENT(muxAcquire - Contention); 4473 ParkEvent * ReleaseAfter = NULL; 4474 if (ev == NULL) { 4475 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4476 } 4477 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4478 for (;;) { 4479 guarantee(ev->OnList == 0, "invariant"); 4480 int its = (os::is_MP() ? 100 : 0) + 1; 4481 4482 // Optional spin phase: spin-then-park strategy 4483 while (--its >= 0) { 4484 w = *Lock; 4485 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4486 if (ReleaseAfter != NULL) { 4487 ParkEvent::Release(ReleaseAfter); 4488 } 4489 return; 4490 } 4491 } 4492 4493 ev->reset(); 4494 ev->OnList = intptr_t(Lock); 4495 // The following fence() isn't _strictly necessary as the subsequent 4496 // CAS() both serializes execution and ratifies the fetched *Lock value. 4497 OrderAccess::fence(); 4498 for (;;) { 4499 w = *Lock; 4500 if ((w & LOCKBIT) == 0) { 4501 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4502 ev->OnList = 0; 4503 // We call ::Release while holding the outer lock, thus 4504 // artificially lengthening the critical section. 4505 // Consider deferring the ::Release() until the subsequent unlock(), 4506 // after we've dropped the outer lock. 4507 if (ReleaseAfter != NULL) { 4508 ParkEvent::Release(ReleaseAfter); 4509 } 4510 return; 4511 } 4512 continue; // Interference -- *Lock changed -- Just retry 4513 } 4514 assert(w & LOCKBIT, "invariant"); 4515 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4516 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4517 } 4518 4519 while (ev->OnList != 0) { 4520 ev->park(); 4521 } 4522 } 4523 } 4524 4525 // Release() must extract a successor from the list and then wake that thread. 4526 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4527 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4528 // Release() would : 4529 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4530 // (B) Extract a successor from the private list "in-hand" 4531 // (C) attempt to CAS() the residual back into *Lock over null. 4532 // If there were any newly arrived threads and the CAS() would fail. 4533 // In that case Release() would detach the RATs, re-merge the list in-hand 4534 // with the RATs and repeat as needed. Alternately, Release() might 4535 // detach and extract a successor, but then pass the residual list to the wakee. 4536 // The wakee would be responsible for reattaching and remerging before it 4537 // competed for the lock. 4538 // 4539 // Both "pop" and DMR are immune from ABA corruption -- there can be 4540 // multiple concurrent pushers, but only one popper or detacher. 4541 // This implementation pops from the head of the list. This is unfair, 4542 // but tends to provide excellent throughput as hot threads remain hot. 4543 // (We wake recently run threads first). 4544 // 4545 // All paths through muxRelease() will execute a CAS. 4546 // Release consistency -- We depend on the CAS in muxRelease() to provide full 4547 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4548 // executed within the critical section are complete and globally visible before the 4549 // store (CAS) to the lock-word that releases the lock becomes globally visible. 4550 void Thread::muxRelease(volatile intptr_t * Lock) { 4551 for (;;) { 4552 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4553 assert(w & LOCKBIT, "invariant"); 4554 if (w == LOCKBIT) return; 4555 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4556 assert(List != NULL, "invariant"); 4557 assert(List->OnList == intptr_t(Lock), "invariant"); 4558 ParkEvent * const nxt = List->ListNext; 4559 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4560 4561 // The following CAS() releases the lock and pops the head element. 4562 // The CAS() also ratifies the previously fetched lock-word value. 4563 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4564 continue; 4565 } 4566 List->OnList = 0; 4567 OrderAccess::fence(); 4568 List->unpark(); 4569 return; 4570 } 4571 } 4572 4573 4574 void Threads::verify() { 4575 ALL_JAVA_THREADS(p) { 4576 p->verify(); 4577 } 4578 VMThread* thread = VMThread::vm_thread(); 4579 if (thread != NULL) thread->verify(); 4580 }