1 /* 2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/classLoader.hpp" 27 #include "classfile/javaClasses.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/codeCache.hpp" 31 #include "code/scopeDesc.hpp" 32 #include "compiler/compileBroker.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "interpreter/linkResolver.hpp" 35 #include "interpreter/oopMapCache.hpp" 36 #include "jvmtifiles/jvmtiEnv.hpp" 37 #include "memory/gcLocker.inline.hpp" 38 #include "memory/metaspaceShared.hpp" 39 #include "memory/oopFactory.hpp" 40 #include "memory/universe.inline.hpp" 41 #include "oops/instanceKlass.hpp" 42 #include "oops/objArrayOop.hpp" 43 #include "oops/oop.inline.hpp" 44 #include "oops/symbol.hpp" 45 #include "prims/jvm_misc.hpp" 46 #include "prims/jvmtiExport.hpp" 47 #include "prims/jvmtiThreadState.hpp" 48 #include "prims/privilegedStack.hpp" 49 #include "runtime/arguments.hpp" 50 #include "runtime/atomic.inline.hpp" 51 #include "runtime/biasedLocking.hpp" 52 #include "runtime/deoptimization.hpp" 53 #include "runtime/fprofiler.hpp" 54 #include "runtime/frame.inline.hpp" 55 #include "runtime/init.hpp" 56 #include "runtime/interfaceSupport.hpp" 57 #include "runtime/java.hpp" 58 #include "runtime/javaCalls.hpp" 59 #include "runtime/jniPeriodicChecker.hpp" 60 #include "runtime/memprofiler.hpp" 61 #include "runtime/mutexLocker.hpp" 62 #include "runtime/objectMonitor.hpp" 63 #include "runtime/orderAccess.inline.hpp" 64 #include "runtime/osThread.hpp" 65 #include "runtime/safepoint.hpp" 66 #include "runtime/sharedRuntime.hpp" 67 #include "runtime/statSampler.hpp" 68 #include "runtime/stubRoutines.hpp" 69 #include "runtime/sweeper.hpp" 70 #include "runtime/task.hpp" 71 #include "runtime/thread.inline.hpp" 72 #include "runtime/threadCritical.hpp" 73 #include "runtime/threadLocalStorage.hpp" 74 #include "runtime/vframe.hpp" 75 #include "runtime/vframeArray.hpp" 76 #include "runtime/vframe_hp.hpp" 77 #include "runtime/vmThread.hpp" 78 #include "runtime/vm_operations.hpp" 79 #include "runtime/vm_version.hpp" 80 #include "services/attachListener.hpp" 81 #include "services/management.hpp" 82 #include "services/memTracker.hpp" 83 #include "services/threadService.hpp" 84 #include "trace/tracing.hpp" 85 #include "trace/traceMacros.hpp" 86 #include "utilities/defaultStream.hpp" 87 #include "utilities/dtrace.hpp" 88 #include "utilities/events.hpp" 89 #include "utilities/preserveException.hpp" 90 #include "utilities/macros.hpp" 91 #if INCLUDE_ALL_GCS 92 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 93 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 94 #include "gc_implementation/parallelScavenge/pcTasks.hpp" 95 #endif // INCLUDE_ALL_GCS 96 #ifdef COMPILER1 97 #include "c1/c1_Compiler.hpp" 98 #endif 99 #ifdef COMPILER2 100 #include "opto/c2compiler.hpp" 101 #include "opto/idealGraphPrinter.hpp" 102 #endif 103 #if INCLUDE_RTM_OPT 104 #include "runtime/rtmLocking.hpp" 105 #endif 106 107 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 108 109 #ifdef DTRACE_ENABLED 110 111 // Only bother with this argument setup if dtrace is available 112 113 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 114 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 115 116 #define DTRACE_THREAD_PROBE(probe, javathread) \ 117 { \ 118 ResourceMark rm(this); \ 119 int len = 0; \ 120 const char* name = (javathread)->get_thread_name(); \ 121 len = strlen(name); \ 122 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 123 (char *) name, len, \ 124 java_lang_Thread::thread_id((javathread)->threadObj()), \ 125 (uintptr_t) (javathread)->osthread()->thread_id(), \ 126 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 127 } 128 129 #else // ndef DTRACE_ENABLED 130 131 #define DTRACE_THREAD_PROBE(probe, javathread) 132 133 #endif // ndef DTRACE_ENABLED 134 135 136 // Class hierarchy 137 // - Thread 138 // - VMThread 139 // - WatcherThread 140 // - ConcurrentMarkSweepThread 141 // - JavaThread 142 // - CompilerThread 143 144 // ======= Thread ======== 145 // Support for forcing alignment of thread objects for biased locking 146 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 147 if (UseBiasedLocking) { 148 const int alignment = markOopDesc::biased_lock_alignment; 149 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 150 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 151 : AllocateHeap(aligned_size, flags, CURRENT_PC, 152 AllocFailStrategy::RETURN_NULL); 153 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 154 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 155 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 156 "JavaThread alignment code overflowed allocated storage"); 157 if (TraceBiasedLocking) { 158 if (aligned_addr != real_malloc_addr) { 159 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 160 real_malloc_addr, aligned_addr); 161 } 162 } 163 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 164 return aligned_addr; 165 } else { 166 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 167 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 168 } 169 } 170 171 void Thread::operator delete(void* p) { 172 if (UseBiasedLocking) { 173 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 174 FreeHeap(real_malloc_addr); 175 } else { 176 FreeHeap(p); 177 } 178 } 179 180 181 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 182 // JavaThread 183 184 185 Thread::Thread() { 186 // stack and get_thread 187 set_stack_base(NULL); 188 set_stack_size(0); 189 set_self_raw_id(0); 190 set_lgrp_id(-1); 191 192 // allocated data structures 193 set_osthread(NULL); 194 set_resource_area(new (mtThread)ResourceArea()); 195 DEBUG_ONLY(_current_resource_mark = NULL;) 196 set_handle_area(new (mtThread) HandleArea(NULL)); 197 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 198 set_active_handles(NULL); 199 set_free_handle_block(NULL); 200 set_last_handle_mark(NULL); 201 202 // This initial value ==> never claimed. 203 _oops_do_parity = 0; 204 205 _metadata_on_stack_buffer = NULL; 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 _suspend_flags = 0; 235 236 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 237 _hashStateX = os::random(); 238 _hashStateY = 842502087; 239 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 240 _hashStateW = 273326509; 241 242 _OnTrap = 0; 243 _schedctl = NULL; 244 _Stalled = 0; 245 _TypeTag = 0x2BAD; 246 247 // Many of the following fields are effectively final - immutable 248 // Note that nascent threads can't use the Native Monitor-Mutex 249 // construct until the _MutexEvent is initialized ... 250 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 251 // we might instead use a stack of ParkEvents that we could provision on-demand. 252 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 253 // and ::Release() 254 _ParkEvent = ParkEvent::Allocate(this); 255 _SleepEvent = ParkEvent::Allocate(this); 256 _MutexEvent = ParkEvent::Allocate(this); 257 _MuxEvent = ParkEvent::Allocate(this); 258 259 #ifdef CHECK_UNHANDLED_OOPS 260 if (CheckUnhandledOops) { 261 _unhandled_oops = new UnhandledOops(this); 262 } 263 #endif // CHECK_UNHANDLED_OOPS 264 #ifdef ASSERT 265 if (UseBiasedLocking) { 266 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 267 assert(this == _real_malloc_address || 268 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 269 "bug in forced alignment of thread objects"); 270 } 271 #endif // ASSERT 272 } 273 274 void Thread::initialize_thread_local_storage() { 275 // Note: Make sure this method only calls 276 // non-blocking operations. Otherwise, it might not work 277 // with the thread-startup/safepoint interaction. 278 279 // During Java thread startup, safepoint code should allow this 280 // method to complete because it may need to allocate memory to 281 // store information for the new thread. 282 283 // initialize structure dependent on thread local storage 284 ThreadLocalStorage::set_thread(this); 285 } 286 287 void Thread::record_stack_base_and_size() { 288 set_stack_base(os::current_stack_base()); 289 set_stack_size(os::current_stack_size()); 290 if (is_Java_thread()) { 291 ((JavaThread*) this)->set_stack_overflow_limit(); 292 } 293 // CR 7190089: on Solaris, primordial thread's stack is adjusted 294 // in initialize_thread(). Without the adjustment, stack size is 295 // incorrect if stack is set to unlimited (ulimit -s unlimited). 296 // So far, only Solaris has real implementation of initialize_thread(). 297 // 298 // set up any platform-specific state. 299 os::initialize_thread(this); 300 301 #if INCLUDE_NMT 302 // record thread's native stack, stack grows downward 303 address stack_low_addr = stack_base() - stack_size(); 304 MemTracker::record_thread_stack(stack_low_addr, stack_size()); 305 #endif // INCLUDE_NMT 306 } 307 308 309 Thread::~Thread() { 310 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 311 ObjectSynchronizer::omFlush(this); 312 313 EVENT_THREAD_DESTRUCT(this); 314 315 // stack_base can be NULL if the thread is never started or exited before 316 // record_stack_base_and_size called. Although, we would like to ensure 317 // that all started threads do call record_stack_base_and_size(), there is 318 // not proper way to enforce that. 319 #if INCLUDE_NMT 320 if (_stack_base != NULL) { 321 address low_stack_addr = stack_base() - stack_size(); 322 MemTracker::release_thread_stack(low_stack_addr, stack_size()); 323 #ifdef ASSERT 324 set_stack_base(NULL); 325 #endif 326 } 327 #endif // INCLUDE_NMT 328 329 // deallocate data structures 330 delete resource_area(); 331 // since the handle marks are using the handle area, we have to deallocated the root 332 // handle mark before deallocating the thread's handle area, 333 assert(last_handle_mark() != NULL, "check we have an element"); 334 delete last_handle_mark(); 335 assert(last_handle_mark() == NULL, "check we have reached the end"); 336 337 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 338 // We NULL out the fields for good hygiene. 339 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 340 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 341 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 342 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 343 344 delete handle_area(); 345 delete metadata_handles(); 346 347 // osthread() can be NULL, if creation of thread failed. 348 if (osthread() != NULL) os::free_thread(osthread()); 349 350 delete _SR_lock; 351 352 // clear thread local storage if the Thread is deleting itself 353 if (this == Thread::current()) { 354 ThreadLocalStorage::set_thread(NULL); 355 } else { 356 // In the case where we're not the current thread, invalidate all the 357 // caches in case some code tries to get the current thread or the 358 // thread that was destroyed, and gets stale information. 359 ThreadLocalStorage::invalidate_all(); 360 } 361 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 362 } 363 364 // NOTE: dummy function for assertion purpose. 365 void Thread::run() { 366 ShouldNotReachHere(); 367 } 368 369 #ifdef ASSERT 370 // Private method to check for dangling thread pointer 371 void check_for_dangling_thread_pointer(Thread *thread) { 372 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 373 "possibility of dangling Thread pointer"); 374 } 375 #endif 376 377 ThreadPriority Thread::get_priority(const Thread* const thread) { 378 ThreadPriority priority; 379 // Can return an error! 380 (void)os::get_priority(thread, priority); 381 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 382 return priority; 383 } 384 385 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 386 debug_only(check_for_dangling_thread_pointer(thread);) 387 // Can return an error! 388 (void)os::set_priority(thread, priority); 389 } 390 391 392 void Thread::start(Thread* thread) { 393 // Start is different from resume in that its safety is guaranteed by context or 394 // being called from a Java method synchronized on the Thread object. 395 if (!DisableStartThread) { 396 if (thread->is_Java_thread()) { 397 // Initialize the thread state to RUNNABLE before starting this thread. 398 // Can not set it after the thread started because we do not know the 399 // exact thread state at that time. It could be in MONITOR_WAIT or 400 // in SLEEPING or some other state. 401 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 402 java_lang_Thread::RUNNABLE); 403 } 404 os::start_thread(thread); 405 } 406 } 407 408 // Enqueue a VM_Operation to do the job for us - sometime later 409 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 410 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 411 VMThread::execute(vm_stop); 412 } 413 414 415 // Check if an external suspend request has completed (or has been 416 // cancelled). Returns true if the thread is externally suspended and 417 // false otherwise. 418 // 419 // The bits parameter returns information about the code path through 420 // the routine. Useful for debugging: 421 // 422 // set in is_ext_suspend_completed(): 423 // 0x00000001 - routine was entered 424 // 0x00000010 - routine return false at end 425 // 0x00000100 - thread exited (return false) 426 // 0x00000200 - suspend request cancelled (return false) 427 // 0x00000400 - thread suspended (return true) 428 // 0x00001000 - thread is in a suspend equivalent state (return true) 429 // 0x00002000 - thread is native and walkable (return true) 430 // 0x00004000 - thread is native_trans and walkable (needed retry) 431 // 432 // set in wait_for_ext_suspend_completion(): 433 // 0x00010000 - routine was entered 434 // 0x00020000 - suspend request cancelled before loop (return false) 435 // 0x00040000 - thread suspended before loop (return true) 436 // 0x00080000 - suspend request cancelled in loop (return false) 437 // 0x00100000 - thread suspended in loop (return true) 438 // 0x00200000 - suspend not completed during retry loop (return false) 439 440 // Helper class for tracing suspend wait debug bits. 441 // 442 // 0x00000100 indicates that the target thread exited before it could 443 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 444 // 0x00080000 each indicate a cancelled suspend request so they don't 445 // count as wait failures either. 446 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 447 448 class TraceSuspendDebugBits : public StackObj { 449 private: 450 JavaThread * jt; 451 bool is_wait; 452 bool called_by_wait; // meaningful when !is_wait 453 uint32_t * bits; 454 455 public: 456 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 457 uint32_t *_bits) { 458 jt = _jt; 459 is_wait = _is_wait; 460 called_by_wait = _called_by_wait; 461 bits = _bits; 462 } 463 464 ~TraceSuspendDebugBits() { 465 if (!is_wait) { 466 #if 1 467 // By default, don't trace bits for is_ext_suspend_completed() calls. 468 // That trace is very chatty. 469 return; 470 #else 471 if (!called_by_wait) { 472 // If tracing for is_ext_suspend_completed() is enabled, then only 473 // trace calls to it from wait_for_ext_suspend_completion() 474 return; 475 } 476 #endif 477 } 478 479 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 480 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 481 MutexLocker ml(Threads_lock); // needed for get_thread_name() 482 ResourceMark rm; 483 484 tty->print_cr( 485 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 486 jt->get_thread_name(), *bits); 487 488 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 489 } 490 } 491 } 492 }; 493 #undef DEBUG_FALSE_BITS 494 495 496 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 497 uint32_t *bits) { 498 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 499 500 bool did_trans_retry = false; // only do thread_in_native_trans retry once 501 bool do_trans_retry; // flag to force the retry 502 503 *bits |= 0x00000001; 504 505 do { 506 do_trans_retry = false; 507 508 if (is_exiting()) { 509 // Thread is in the process of exiting. This is always checked 510 // first to reduce the risk of dereferencing a freed JavaThread. 511 *bits |= 0x00000100; 512 return false; 513 } 514 515 if (!is_external_suspend()) { 516 // Suspend request is cancelled. This is always checked before 517 // is_ext_suspended() to reduce the risk of a rogue resume 518 // confusing the thread that made the suspend request. 519 *bits |= 0x00000200; 520 return false; 521 } 522 523 if (is_ext_suspended()) { 524 // thread is suspended 525 *bits |= 0x00000400; 526 return true; 527 } 528 529 // Now that we no longer do hard suspends of threads running 530 // native code, the target thread can be changing thread state 531 // while we are in this routine: 532 // 533 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 534 // 535 // We save a copy of the thread state as observed at this moment 536 // and make our decision about suspend completeness based on the 537 // copy. This closes the race where the thread state is seen as 538 // _thread_in_native_trans in the if-thread_blocked check, but is 539 // seen as _thread_blocked in if-thread_in_native_trans check. 540 JavaThreadState save_state = thread_state(); 541 542 if (save_state == _thread_blocked && is_suspend_equivalent()) { 543 // If the thread's state is _thread_blocked and this blocking 544 // condition is known to be equivalent to a suspend, then we can 545 // consider the thread to be externally suspended. This means that 546 // the code that sets _thread_blocked has been modified to do 547 // self-suspension if the blocking condition releases. We also 548 // used to check for CONDVAR_WAIT here, but that is now covered by 549 // the _thread_blocked with self-suspension check. 550 // 551 // Return true since we wouldn't be here unless there was still an 552 // external suspend request. 553 *bits |= 0x00001000; 554 return true; 555 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 556 // Threads running native code will self-suspend on native==>VM/Java 557 // transitions. If its stack is walkable (should always be the case 558 // unless this function is called before the actual java_suspend() 559 // call), then the wait is done. 560 *bits |= 0x00002000; 561 return true; 562 } else if (!called_by_wait && !did_trans_retry && 563 save_state == _thread_in_native_trans && 564 frame_anchor()->walkable()) { 565 // The thread is transitioning from thread_in_native to another 566 // thread state. check_safepoint_and_suspend_for_native_trans() 567 // will force the thread to self-suspend. If it hasn't gotten 568 // there yet we may have caught the thread in-between the native 569 // code check above and the self-suspend. Lucky us. If we were 570 // called by wait_for_ext_suspend_completion(), then it 571 // will be doing the retries so we don't have to. 572 // 573 // Since we use the saved thread state in the if-statement above, 574 // there is a chance that the thread has already transitioned to 575 // _thread_blocked by the time we get here. In that case, we will 576 // make a single unnecessary pass through the logic below. This 577 // doesn't hurt anything since we still do the trans retry. 578 579 *bits |= 0x00004000; 580 581 // Once the thread leaves thread_in_native_trans for another 582 // thread state, we break out of this retry loop. We shouldn't 583 // need this flag to prevent us from getting back here, but 584 // sometimes paranoia is good. 585 did_trans_retry = true; 586 587 // We wait for the thread to transition to a more usable state. 588 for (int i = 1; i <= SuspendRetryCount; i++) { 589 // We used to do an "os::yield_all(i)" call here with the intention 590 // that yielding would increase on each retry. However, the parameter 591 // is ignored on Linux which means the yield didn't scale up. Waiting 592 // on the SR_lock below provides a much more predictable scale up for 593 // the delay. It also provides a simple/direct point to check for any 594 // safepoint requests from the VMThread 595 596 // temporarily drops SR_lock while doing wait with safepoint check 597 // (if we're a JavaThread - the WatcherThread can also call this) 598 // and increase delay with each retry 599 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 600 601 // check the actual thread state instead of what we saved above 602 if (thread_state() != _thread_in_native_trans) { 603 // the thread has transitioned to another thread state so 604 // try all the checks (except this one) one more time. 605 do_trans_retry = true; 606 break; 607 } 608 } // end retry loop 609 610 611 } 612 } while (do_trans_retry); 613 614 *bits |= 0x00000010; 615 return false; 616 } 617 618 // Wait for an external suspend request to complete (or be cancelled). 619 // Returns true if the thread is externally suspended and false otherwise. 620 // 621 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 622 uint32_t *bits) { 623 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 624 false /* !called_by_wait */, bits); 625 626 // local flag copies to minimize SR_lock hold time 627 bool is_suspended; 628 bool pending; 629 uint32_t reset_bits; 630 631 // set a marker so is_ext_suspend_completed() knows we are the caller 632 *bits |= 0x00010000; 633 634 // We use reset_bits to reinitialize the bits value at the top of 635 // each retry loop. This allows the caller to make use of any 636 // unused bits for their own marking purposes. 637 reset_bits = *bits; 638 639 { 640 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 641 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 642 delay, bits); 643 pending = is_external_suspend(); 644 } 645 // must release SR_lock to allow suspension to complete 646 647 if (!pending) { 648 // A cancelled suspend request is the only false return from 649 // is_ext_suspend_completed() that keeps us from entering the 650 // retry loop. 651 *bits |= 0x00020000; 652 return false; 653 } 654 655 if (is_suspended) { 656 *bits |= 0x00040000; 657 return true; 658 } 659 660 for (int i = 1; i <= retries; i++) { 661 *bits = reset_bits; // reinit to only track last retry 662 663 // We used to do an "os::yield_all(i)" call here with the intention 664 // that yielding would increase on each retry. However, the parameter 665 // is ignored on Linux which means the yield didn't scale up. Waiting 666 // on the SR_lock below provides a much more predictable scale up for 667 // the delay. It also provides a simple/direct point to check for any 668 // safepoint requests from the VMThread 669 670 { 671 MutexLocker ml(SR_lock()); 672 // wait with safepoint check (if we're a JavaThread - the WatcherThread 673 // can also call this) and increase delay with each retry 674 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 675 676 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 677 delay, bits); 678 679 // It is possible for the external suspend request to be cancelled 680 // (by a resume) before the actual suspend operation is completed. 681 // Refresh our local copy to see if we still need to wait. 682 pending = is_external_suspend(); 683 } 684 685 if (!pending) { 686 // A cancelled suspend request is the only false return from 687 // is_ext_suspend_completed() that keeps us from staying in the 688 // retry loop. 689 *bits |= 0x00080000; 690 return false; 691 } 692 693 if (is_suspended) { 694 *bits |= 0x00100000; 695 return true; 696 } 697 } // end retry loop 698 699 // thread did not suspend after all our retries 700 *bits |= 0x00200000; 701 return false; 702 } 703 704 #ifndef PRODUCT 705 void JavaThread::record_jump(address target, address instr, const char* file, 706 int line) { 707 708 // This should not need to be atomic as the only way for simultaneous 709 // updates is via interrupts. Even then this should be rare or non-existent 710 // and we don't care that much anyway. 711 712 int index = _jmp_ring_index; 713 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 714 _jmp_ring[index]._target = (intptr_t) target; 715 _jmp_ring[index]._instruction = (intptr_t) instr; 716 _jmp_ring[index]._file = file; 717 _jmp_ring[index]._line = line; 718 } 719 #endif // PRODUCT 720 721 // Called by flat profiler 722 // Callers have already called wait_for_ext_suspend_completion 723 // The assertion for that is currently too complex to put here: 724 bool JavaThread::profile_last_Java_frame(frame* _fr) { 725 bool gotframe = false; 726 // self suspension saves needed state. 727 if (has_last_Java_frame() && _anchor.walkable()) { 728 *_fr = pd_last_frame(); 729 gotframe = true; 730 } 731 return gotframe; 732 } 733 734 void Thread::interrupt(Thread* thread) { 735 debug_only(check_for_dangling_thread_pointer(thread);) 736 os::interrupt(thread); 737 } 738 739 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 740 debug_only(check_for_dangling_thread_pointer(thread);) 741 // Note: If clear_interrupted==false, this simply fetches and 742 // returns the value of the field osthread()->interrupted(). 743 return os::is_interrupted(thread, clear_interrupted); 744 } 745 746 747 // GC Support 748 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 749 jint thread_parity = _oops_do_parity; 750 if (thread_parity != strong_roots_parity) { 751 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 752 if (res == thread_parity) { 753 return true; 754 } else { 755 guarantee(res == strong_roots_parity, "Or else what?"); 756 assert(SharedHeap::heap()->workers()->active_workers() > 0, 757 "Should only fail when parallel."); 758 return false; 759 } 760 } 761 assert(SharedHeap::heap()->workers()->active_workers() > 0, 762 "Should only fail when parallel."); 763 return false; 764 } 765 766 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 767 active_handles()->oops_do(f); 768 // Do oop for ThreadShadow 769 f->do_oop((oop*)&_pending_exception); 770 handle_area()->oops_do(f); 771 } 772 773 void Thread::nmethods_do(CodeBlobClosure* cf) { 774 // no nmethods in a generic thread... 775 } 776 777 void Thread::metadata_do(void f(Metadata*)) { 778 if (metadata_handles() != NULL) { 779 for (int i = 0; i< metadata_handles()->length(); i++) { 780 f(metadata_handles()->at(i)); 781 } 782 } 783 } 784 785 void Thread::print_on(outputStream* st) const { 786 // get_priority assumes osthread initialized 787 if (osthread() != NULL) { 788 int os_prio; 789 if (os::get_native_priority(this, &os_prio) == OS_OK) { 790 st->print("os_prio=%d ", os_prio); 791 } 792 st->print("tid=" INTPTR_FORMAT " ", this); 793 ext().print_on(st); 794 osthread()->print_on(st); 795 } 796 debug_only(if (WizardMode) print_owned_locks_on(st);) 797 } 798 799 // Thread::print_on_error() is called by fatal error handler. Don't use 800 // any lock or allocate memory. 801 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 802 if (is_VM_thread()) st->print("VMThread"); 803 else if (is_Compiler_thread()) st->print("CompilerThread"); 804 else if (is_Java_thread()) st->print("JavaThread"); 805 else if (is_GC_task_thread()) st->print("GCTaskThread"); 806 else if (is_Watcher_thread()) st->print("WatcherThread"); 807 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 808 else st->print("Thread"); 809 810 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 811 _stack_base - _stack_size, _stack_base); 812 813 if (osthread()) { 814 st->print(" [id=%d]", osthread()->thread_id()); 815 } 816 } 817 818 #ifdef ASSERT 819 void Thread::print_owned_locks_on(outputStream* st) const { 820 Monitor *cur = _owned_locks; 821 if (cur == NULL) { 822 st->print(" (no locks) "); 823 } else { 824 st->print_cr(" Locks owned:"); 825 while (cur) { 826 cur->print_on(st); 827 cur = cur->next(); 828 } 829 } 830 } 831 832 static int ref_use_count = 0; 833 834 bool Thread::owns_locks_but_compiled_lock() const { 835 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 836 if (cur != Compile_lock) return true; 837 } 838 return false; 839 } 840 841 842 #endif 843 844 #ifndef PRODUCT 845 846 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 847 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 848 // no threads which allow_vm_block's are held 849 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 850 // Check if current thread is allowed to block at a safepoint 851 if (!(_allow_safepoint_count == 0)) { 852 fatal("Possible safepoint reached by thread that does not allow it"); 853 } 854 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 855 fatal("LEAF method calling lock?"); 856 } 857 858 #ifdef ASSERT 859 if (potential_vm_operation && is_Java_thread() 860 && !Universe::is_bootstrapping()) { 861 // Make sure we do not hold any locks that the VM thread also uses. 862 // This could potentially lead to deadlocks 863 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 864 // Threads_lock is special, since the safepoint synchronization will not start before this is 865 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 866 // since it is used to transfer control between JavaThreads and the VMThread 867 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 868 if ((cur->allow_vm_block() && 869 cur != Threads_lock && 870 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 871 cur != VMOperationRequest_lock && 872 cur != VMOperationQueue_lock) || 873 cur->rank() == Mutex::special) { 874 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name())); 875 } 876 } 877 } 878 879 if (GCALotAtAllSafepoints) { 880 // We could enter a safepoint here and thus have a gc 881 InterfaceSupport::check_gc_alot(); 882 } 883 #endif 884 } 885 #endif 886 887 bool Thread::is_in_stack(address adr) const { 888 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 889 address end = os::current_stack_pointer(); 890 // Allow non Java threads to call this without stack_base 891 if (_stack_base == NULL) return true; 892 if (stack_base() >= adr && adr >= end) return true; 893 894 return false; 895 } 896 897 898 bool Thread::is_in_usable_stack(address adr) const { 899 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 900 size_t usable_stack_size = _stack_size - stack_guard_size; 901 902 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 903 } 904 905 906 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 907 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 908 // used for compilation in the future. If that change is made, the need for these methods 909 // should be revisited, and they should be removed if possible. 910 911 bool Thread::is_lock_owned(address adr) const { 912 return on_local_stack(adr); 913 } 914 915 bool Thread::set_as_starting_thread() { 916 // NOTE: this must be called inside the main thread. 917 return os::create_main_thread((JavaThread*)this); 918 } 919 920 static void initialize_class(Symbol* class_name, TRAPS) { 921 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 922 InstanceKlass::cast(klass)->initialize(CHECK); 923 } 924 925 926 // Creates the initial ThreadGroup 927 static Handle create_initial_thread_group(TRAPS) { 928 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 929 instanceKlassHandle klass (THREAD, k); 930 931 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 932 { 933 JavaValue result(T_VOID); 934 JavaCalls::call_special(&result, 935 system_instance, 936 klass, 937 vmSymbols::object_initializer_name(), 938 vmSymbols::void_method_signature(), 939 CHECK_NH); 940 } 941 Universe::set_system_thread_group(system_instance()); 942 943 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 944 { 945 JavaValue result(T_VOID); 946 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 947 JavaCalls::call_special(&result, 948 main_instance, 949 klass, 950 vmSymbols::object_initializer_name(), 951 vmSymbols::threadgroup_string_void_signature(), 952 system_instance, 953 string, 954 CHECK_NH); 955 } 956 return main_instance; 957 } 958 959 // Creates the initial Thread 960 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 961 TRAPS) { 962 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 963 instanceKlassHandle klass (THREAD, k); 964 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 965 966 java_lang_Thread::set_thread(thread_oop(), thread); 967 java_lang_Thread::set_priority(thread_oop(), NormPriority); 968 thread->set_threadObj(thread_oop()); 969 970 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 971 972 JavaValue result(T_VOID); 973 JavaCalls::call_special(&result, thread_oop, 974 klass, 975 vmSymbols::object_initializer_name(), 976 vmSymbols::threadgroup_string_void_signature(), 977 thread_group, 978 string, 979 CHECK_NULL); 980 return thread_oop(); 981 } 982 983 static void call_initializeSystemClass(TRAPS) { 984 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 985 instanceKlassHandle klass (THREAD, k); 986 987 JavaValue result(T_VOID); 988 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 989 vmSymbols::void_method_signature(), CHECK); 990 } 991 992 char java_runtime_name[128] = ""; 993 char java_runtime_version[128] = ""; 994 995 // extract the JRE name from sun.misc.Version.java_runtime_name 996 static const char* get_java_runtime_name(TRAPS) { 997 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 998 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 999 fieldDescriptor fd; 1000 bool found = k != NULL && 1001 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1002 vmSymbols::string_signature(), &fd); 1003 if (found) { 1004 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1005 if (name_oop == NULL) { 1006 return NULL; 1007 } 1008 const char* name = java_lang_String::as_utf8_string(name_oop, 1009 java_runtime_name, 1010 sizeof(java_runtime_name)); 1011 return name; 1012 } else { 1013 return NULL; 1014 } 1015 } 1016 1017 // extract the JRE version from sun.misc.Version.java_runtime_version 1018 static const char* get_java_runtime_version(TRAPS) { 1019 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1020 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1021 fieldDescriptor fd; 1022 bool found = k != NULL && 1023 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1024 vmSymbols::string_signature(), &fd); 1025 if (found) { 1026 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1027 if (name_oop == NULL) { 1028 return NULL; 1029 } 1030 const char* name = java_lang_String::as_utf8_string(name_oop, 1031 java_runtime_version, 1032 sizeof(java_runtime_version)); 1033 return name; 1034 } else { 1035 return NULL; 1036 } 1037 } 1038 1039 // General purpose hook into Java code, run once when the VM is initialized. 1040 // The Java library method itself may be changed independently from the VM. 1041 static void call_postVMInitHook(TRAPS) { 1042 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1043 instanceKlassHandle klass (THREAD, k); 1044 if (klass.not_null()) { 1045 JavaValue result(T_VOID); 1046 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1047 vmSymbols::void_method_signature(), 1048 CHECK); 1049 } 1050 } 1051 1052 static void reset_vm_info_property(TRAPS) { 1053 // the vm info string 1054 ResourceMark rm(THREAD); 1055 const char *vm_info = VM_Version::vm_info_string(); 1056 1057 // java.lang.System class 1058 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1059 instanceKlassHandle klass (THREAD, k); 1060 1061 // setProperty arguments 1062 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1063 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1064 1065 // return value 1066 JavaValue r(T_OBJECT); 1067 1068 // public static String setProperty(String key, String value); 1069 JavaCalls::call_static(&r, 1070 klass, 1071 vmSymbols::setProperty_name(), 1072 vmSymbols::string_string_string_signature(), 1073 key_str, 1074 value_str, 1075 CHECK); 1076 } 1077 1078 1079 void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, 1080 bool daemon, TRAPS) { 1081 assert(thread_group.not_null(), "thread group should be specified"); 1082 assert(threadObj() == NULL, "should only create Java thread object once"); 1083 1084 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1085 instanceKlassHandle klass (THREAD, k); 1086 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1087 1088 java_lang_Thread::set_thread(thread_oop(), this); 1089 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1090 set_threadObj(thread_oop()); 1091 1092 JavaValue result(T_VOID); 1093 if (thread_name != NULL) { 1094 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1095 // Thread gets assigned specified name and null target 1096 JavaCalls::call_special(&result, 1097 thread_oop, 1098 klass, 1099 vmSymbols::object_initializer_name(), 1100 vmSymbols::threadgroup_string_void_signature(), 1101 thread_group, // Argument 1 1102 name, // Argument 2 1103 THREAD); 1104 } else { 1105 // Thread gets assigned name "Thread-nnn" and null target 1106 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1107 JavaCalls::call_special(&result, 1108 thread_oop, 1109 klass, 1110 vmSymbols::object_initializer_name(), 1111 vmSymbols::threadgroup_runnable_void_signature(), 1112 thread_group, // Argument 1 1113 Handle(), // Argument 2 1114 THREAD); 1115 } 1116 1117 1118 if (daemon) { 1119 java_lang_Thread::set_daemon(thread_oop()); 1120 } 1121 1122 if (HAS_PENDING_EXCEPTION) { 1123 return; 1124 } 1125 1126 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1127 Handle threadObj(this, this->threadObj()); 1128 1129 JavaCalls::call_special(&result, 1130 thread_group, 1131 group, 1132 vmSymbols::add_method_name(), 1133 vmSymbols::thread_void_signature(), 1134 threadObj, // Arg 1 1135 THREAD); 1136 1137 1138 } 1139 1140 // NamedThread -- non-JavaThread subclasses with multiple 1141 // uniquely named instances should derive from this. 1142 NamedThread::NamedThread() : Thread() { 1143 _name = NULL; 1144 _processed_thread = NULL; 1145 } 1146 1147 NamedThread::~NamedThread() { 1148 if (_name != NULL) { 1149 FREE_C_HEAP_ARRAY(char, _name); 1150 _name = NULL; 1151 } 1152 } 1153 1154 void NamedThread::set_name(const char* format, ...) { 1155 guarantee(_name == NULL, "Only get to set name once."); 1156 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1157 guarantee(_name != NULL, "alloc failure"); 1158 va_list ap; 1159 va_start(ap, format); 1160 jio_vsnprintf(_name, max_name_len, format, ap); 1161 va_end(ap); 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 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1201 1202 // remaining will be zero if there are no tasks, 1203 // causing the WatcherThread to sleep until a task is 1204 // enrolled 1205 int remaining = PeriodicTask::time_to_wait(); 1206 int time_slept = 0; 1207 1208 // we expect this to timeout - we only ever get unparked when 1209 // we should terminate or when a new task has been enrolled 1210 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1211 1212 jlong time_before_loop = os::javaTimeNanos(); 1213 1214 for (;;) { 1215 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1216 jlong now = os::javaTimeNanos(); 1217 1218 if (remaining == 0) { 1219 // if we didn't have any tasks we could have waited for a long time 1220 // consider the time_slept zero and reset time_before_loop 1221 time_slept = 0; 1222 time_before_loop = now; 1223 } else { 1224 // need to recalculate since we might have new tasks in _tasks 1225 time_slept = (int) ((now - time_before_loop) / 1000000); 1226 } 1227 1228 // Change to task list or spurious wakeup of some kind 1229 if (timedout || _should_terminate) { 1230 break; 1231 } 1232 1233 remaining = PeriodicTask::time_to_wait(); 1234 if (remaining == 0) { 1235 // Last task was just disenrolled so loop around and wait until 1236 // another task gets enrolled 1237 continue; 1238 } 1239 1240 remaining -= time_slept; 1241 if (remaining <= 0) { 1242 break; 1243 } 1244 } 1245 1246 return time_slept; 1247 } 1248 1249 void WatcherThread::run() { 1250 assert(this == watcher_thread(), "just checking"); 1251 1252 this->record_stack_base_and_size(); 1253 this->initialize_thread_local_storage(); 1254 this->set_native_thread_name(this->name()); 1255 this->set_active_handles(JNIHandleBlock::allocate_block()); 1256 while (!_should_terminate) { 1257 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1258 assert(watcher_thread() == this, "thread consistency check"); 1259 1260 // Calculate how long it'll be until the next PeriodicTask work 1261 // should be done, and sleep that amount of time. 1262 int time_waited = sleep(); 1263 1264 if (is_error_reported()) { 1265 // A fatal error has happened, the error handler(VMError::report_and_die) 1266 // should abort JVM after creating an error log file. However in some 1267 // rare cases, the error handler itself might deadlock. Here we try to 1268 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1269 // 1270 // This code is in WatcherThread because WatcherThread wakes up 1271 // periodically so the fatal error handler doesn't need to do anything; 1272 // also because the WatcherThread is less likely to crash than other 1273 // threads. 1274 1275 for (;;) { 1276 if (!ShowMessageBoxOnError 1277 && (OnError == NULL || OnError[0] == '\0') 1278 && Arguments::abort_hook() == NULL) { 1279 os::sleep(this, 2 * 60 * 1000, false); 1280 fdStream err(defaultStream::output_fd()); 1281 err.print_raw_cr("# [ timer expired, abort... ]"); 1282 // skip atexit/vm_exit/vm_abort hooks 1283 os::die(); 1284 } 1285 1286 // Wake up 5 seconds later, the fatal handler may reset OnError or 1287 // ShowMessageBoxOnError when it is ready to abort. 1288 os::sleep(this, 5 * 1000, false); 1289 } 1290 } 1291 1292 PeriodicTask::real_time_tick(time_waited); 1293 } 1294 1295 // Signal that it is terminated 1296 { 1297 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1298 _watcher_thread = NULL; 1299 Terminator_lock->notify(); 1300 } 1301 1302 // Thread destructor usually does this.. 1303 ThreadLocalStorage::set_thread(NULL); 1304 } 1305 1306 void WatcherThread::start() { 1307 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1308 1309 if (watcher_thread() == NULL && _startable) { 1310 _should_terminate = false; 1311 // Create the single instance of WatcherThread 1312 new WatcherThread(); 1313 } 1314 } 1315 1316 void WatcherThread::make_startable() { 1317 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1318 _startable = true; 1319 } 1320 1321 void WatcherThread::stop() { 1322 // Get the PeriodicTask_lock if we can. If we cannot, then the 1323 // WatcherThread is using it and we don't want to block on that lock 1324 // here because that might cause a safepoint deadlock depending on 1325 // what the current WatcherThread tasks are doing. 1326 bool have_lock = PeriodicTask_lock->try_lock(); 1327 1328 _should_terminate = true; 1329 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1330 1331 if (have_lock) { 1332 WatcherThread* watcher = watcher_thread(); 1333 if (watcher != NULL) { 1334 // If we managed to get the lock, then we should unpark the 1335 // WatcherThread so that it can see we want it to stop. 1336 watcher->unpark(); 1337 } 1338 1339 PeriodicTask_lock->unlock(); 1340 } 1341 1342 // it is ok to take late safepoints here, if needed 1343 MutexLocker mu(Terminator_lock); 1344 1345 while (watcher_thread() != NULL) { 1346 // This wait should make safepoint checks, wait without a timeout, 1347 // and wait as a suspend-equivalent condition. 1348 // 1349 // Note: If the FlatProfiler is running, then this thread is waiting 1350 // for the WatcherThread to terminate and the WatcherThread, via the 1351 // FlatProfiler task, is waiting for the external suspend request on 1352 // this thread to complete. wait_for_ext_suspend_completion() will 1353 // eventually timeout, but that takes time. Making this wait a 1354 // suspend-equivalent condition solves that timeout problem. 1355 // 1356 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1357 Mutex::_as_suspend_equivalent_flag); 1358 } 1359 } 1360 1361 void WatcherThread::unpark() { 1362 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() 1363 ? NULL 1364 : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1365 PeriodicTask_lock->notify(); 1366 } 1367 1368 void WatcherThread::print_on(outputStream* st) const { 1369 st->print("\"%s\" ", name()); 1370 Thread::print_on(st); 1371 st->cr(); 1372 } 1373 1374 // ======= JavaThread ======== 1375 1376 // A JavaThread is a normal Java thread 1377 1378 void JavaThread::initialize() { 1379 // Initialize fields 1380 1381 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1382 set_claimed_par_id(UINT_MAX); 1383 1384 set_saved_exception_pc(NULL); 1385 set_threadObj(NULL); 1386 _anchor.clear(); 1387 set_entry_point(NULL); 1388 set_jni_functions(jni_functions()); 1389 set_callee_target(NULL); 1390 set_vm_result(NULL); 1391 set_vm_result_2(NULL); 1392 set_vframe_array_head(NULL); 1393 set_vframe_array_last(NULL); 1394 set_deferred_locals(NULL); 1395 set_deopt_mark(NULL); 1396 set_deopt_nmethod(NULL); 1397 clear_must_deopt_id(); 1398 set_monitor_chunks(NULL); 1399 set_next(NULL); 1400 set_thread_state(_thread_new); 1401 _terminated = _not_terminated; 1402 _privileged_stack_top = NULL; 1403 _array_for_gc = NULL; 1404 _suspend_equivalent = false; 1405 _in_deopt_handler = 0; 1406 _doing_unsafe_access = false; 1407 _stack_guard_state = stack_guard_unused; 1408 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1409 _exception_pc = 0; 1410 _exception_handler_pc = 0; 1411 _is_method_handle_return = 0; 1412 _jvmti_thread_state= NULL; 1413 _should_post_on_exceptions_flag = JNI_FALSE; 1414 _jvmti_get_loaded_classes_closure = NULL; 1415 _interp_only_mode = 0; 1416 _special_runtime_exit_condition = _no_async_condition; 1417 _pending_async_exception = NULL; 1418 _thread_stat = NULL; 1419 _thread_stat = new ThreadStatistics(); 1420 _blocked_on_compilation = false; 1421 _jni_active_critical = 0; 1422 _pending_jni_exception_check_fn = NULL; 1423 _do_not_unlock_if_synchronized = false; 1424 _cached_monitor_info = NULL; 1425 _parker = Parker::Allocate(this); 1426 1427 #ifndef PRODUCT 1428 _jmp_ring_index = 0; 1429 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1430 record_jump(NULL, NULL, NULL, 0); 1431 } 1432 #endif // PRODUCT 1433 1434 set_thread_profiler(NULL); 1435 if (FlatProfiler::is_active()) { 1436 // This is where we would decide to either give each thread it's own profiler 1437 // or use one global one from FlatProfiler, 1438 // or up to some count of the number of profiled threads, etc. 1439 ThreadProfiler* pp = new ThreadProfiler(); 1440 pp->engage(); 1441 set_thread_profiler(pp); 1442 } 1443 1444 // Setup safepoint state info for this thread 1445 ThreadSafepointState::create(this); 1446 1447 debug_only(_java_call_counter = 0); 1448 1449 // JVMTI PopFrame support 1450 _popframe_condition = popframe_inactive; 1451 _popframe_preserved_args = NULL; 1452 _popframe_preserved_args_size = 0; 1453 1454 pd_initialize(); 1455 } 1456 1457 #if INCLUDE_ALL_GCS 1458 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1459 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1460 #endif // INCLUDE_ALL_GCS 1461 1462 JavaThread::JavaThread(bool is_attaching_via_jni) : 1463 Thread() 1464 #if INCLUDE_ALL_GCS 1465 , _satb_mark_queue(&_satb_mark_queue_set), 1466 _dirty_card_queue(&_dirty_card_queue_set) 1467 #endif // INCLUDE_ALL_GCS 1468 { 1469 initialize(); 1470 if (is_attaching_via_jni) { 1471 _jni_attach_state = _attaching_via_jni; 1472 } else { 1473 _jni_attach_state = _not_attaching_via_jni; 1474 } 1475 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1476 } 1477 1478 bool JavaThread::reguard_stack(address cur_sp) { 1479 if (_stack_guard_state != stack_guard_yellow_disabled) { 1480 return true; // Stack already guarded or guard pages not needed. 1481 } 1482 1483 if (register_stack_overflow()) { 1484 // For those architectures which have separate register and 1485 // memory stacks, we must check the register stack to see if 1486 // it has overflowed. 1487 return false; 1488 } 1489 1490 // Java code never executes within the yellow zone: the latter is only 1491 // there to provoke an exception during stack banging. If java code 1492 // is executing there, either StackShadowPages should be larger, or 1493 // some exception code in c1, c2 or the interpreter isn't unwinding 1494 // when it should. 1495 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1496 1497 enable_stack_yellow_zone(); 1498 return true; 1499 } 1500 1501 bool JavaThread::reguard_stack(void) { 1502 return reguard_stack(os::current_stack_pointer()); 1503 } 1504 1505 1506 void JavaThread::block_if_vm_exited() { 1507 if (_terminated == _vm_exited) { 1508 // _vm_exited is set at safepoint, and Threads_lock is never released 1509 // we will block here forever 1510 Threads_lock->lock_without_safepoint_check(); 1511 ShouldNotReachHere(); 1512 } 1513 } 1514 1515 1516 // Remove this ifdef when C1 is ported to the compiler interface. 1517 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1518 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1519 1520 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1521 Thread() 1522 #if INCLUDE_ALL_GCS 1523 , _satb_mark_queue(&_satb_mark_queue_set), 1524 _dirty_card_queue(&_dirty_card_queue_set) 1525 #endif // INCLUDE_ALL_GCS 1526 { 1527 initialize(); 1528 _jni_attach_state = _not_attaching_via_jni; 1529 set_entry_point(entry_point); 1530 // Create the native thread itself. 1531 // %note runtime_23 1532 os::ThreadType thr_type = os::java_thread; 1533 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1534 os::java_thread; 1535 os::create_thread(this, thr_type, stack_sz); 1536 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1537 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1538 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1539 // the exception consists of creating the exception object & initializing it, initialization 1540 // will leave the VM via a JavaCall and then all locks must be unlocked). 1541 // 1542 // The thread is still suspended when we reach here. Thread must be explicit started 1543 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1544 // by calling Threads:add. The reason why this is not done here, is because the thread 1545 // object must be fully initialized (take a look at JVM_Start) 1546 } 1547 1548 JavaThread::~JavaThread() { 1549 1550 // JSR166 -- return the parker to the free list 1551 Parker::Release(_parker); 1552 _parker = NULL; 1553 1554 // Free any remaining previous UnrollBlock 1555 vframeArray* old_array = vframe_array_last(); 1556 1557 if (old_array != NULL) { 1558 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1559 old_array->set_unroll_block(NULL); 1560 delete old_info; 1561 delete old_array; 1562 } 1563 1564 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1565 if (deferred != NULL) { 1566 // This can only happen if thread is destroyed before deoptimization occurs. 1567 assert(deferred->length() != 0, "empty array!"); 1568 do { 1569 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1570 deferred->remove_at(0); 1571 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1572 delete dlv; 1573 } while (deferred->length() != 0); 1574 delete deferred; 1575 } 1576 1577 // All Java related clean up happens in exit 1578 ThreadSafepointState::destroy(this); 1579 if (_thread_profiler != NULL) delete _thread_profiler; 1580 if (_thread_stat != NULL) delete _thread_stat; 1581 } 1582 1583 1584 // The first routine called by a new Java thread 1585 void JavaThread::run() { 1586 // initialize thread-local alloc buffer related fields 1587 this->initialize_tlab(); 1588 1589 // used to test validity of stack trace backs 1590 this->record_base_of_stack_pointer(); 1591 1592 // Record real stack base and size. 1593 this->record_stack_base_and_size(); 1594 1595 // Initialize thread local storage; set before calling MutexLocker 1596 this->initialize_thread_local_storage(); 1597 1598 this->create_stack_guard_pages(); 1599 1600 this->cache_global_variables(); 1601 1602 // Thread is now sufficient initialized to be handled by the safepoint code as being 1603 // in the VM. Change thread state from _thread_new to _thread_in_vm 1604 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1605 1606 assert(JavaThread::current() == this, "sanity check"); 1607 assert(!Thread::current()->owns_locks(), "sanity check"); 1608 1609 DTRACE_THREAD_PROBE(start, this); 1610 1611 // This operation might block. We call that after all safepoint checks for a new thread has 1612 // been completed. 1613 this->set_active_handles(JNIHandleBlock::allocate_block()); 1614 1615 if (JvmtiExport::should_post_thread_life()) { 1616 JvmtiExport::post_thread_start(this); 1617 } 1618 1619 EventThreadStart event; 1620 if (event.should_commit()) { 1621 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1622 event.commit(); 1623 } 1624 1625 // We call another function to do the rest so we are sure that the stack addresses used 1626 // from there will be lower than the stack base just computed 1627 thread_main_inner(); 1628 1629 // Note, thread is no longer valid at this point! 1630 } 1631 1632 1633 void JavaThread::thread_main_inner() { 1634 assert(JavaThread::current() == this, "sanity check"); 1635 assert(this->threadObj() != NULL, "just checking"); 1636 1637 // Execute thread entry point unless this thread has a pending exception 1638 // or has been stopped before starting. 1639 // Note: Due to JVM_StopThread we can have pending exceptions already! 1640 if (!this->has_pending_exception() && 1641 !java_lang_Thread::is_stillborn(this->threadObj())) { 1642 { 1643 ResourceMark rm(this); 1644 this->set_native_thread_name(this->get_thread_name()); 1645 } 1646 HandleMark hm(this); 1647 this->entry_point()(this, this); 1648 } 1649 1650 DTRACE_THREAD_PROBE(stop, this); 1651 1652 this->exit(false); 1653 delete this; 1654 } 1655 1656 1657 static void ensure_join(JavaThread* thread) { 1658 // We do not need to grap the Threads_lock, since we are operating on ourself. 1659 Handle threadObj(thread, thread->threadObj()); 1660 assert(threadObj.not_null(), "java thread object must exist"); 1661 ObjectLocker lock(threadObj, thread); 1662 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1663 thread->clear_pending_exception(); 1664 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1665 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1666 // Clear the native thread instance - this makes isAlive return false and allows the join() 1667 // to complete once we've done the notify_all below 1668 java_lang_Thread::set_thread(threadObj(), NULL); 1669 lock.notify_all(thread); 1670 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1671 thread->clear_pending_exception(); 1672 } 1673 1674 1675 // For any new cleanup additions, please check to see if they need to be applied to 1676 // cleanup_failed_attach_current_thread as well. 1677 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1678 assert(this == JavaThread::current(), "thread consistency check"); 1679 1680 HandleMark hm(this); 1681 Handle uncaught_exception(this, this->pending_exception()); 1682 this->clear_pending_exception(); 1683 Handle threadObj(this, this->threadObj()); 1684 assert(threadObj.not_null(), "Java thread object should be created"); 1685 1686 if (get_thread_profiler() != NULL) { 1687 get_thread_profiler()->disengage(); 1688 ResourceMark rm; 1689 get_thread_profiler()->print(get_thread_name()); 1690 } 1691 1692 1693 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1694 { 1695 EXCEPTION_MARK; 1696 1697 CLEAR_PENDING_EXCEPTION; 1698 } 1699 if (!destroy_vm) { 1700 if (uncaught_exception.not_null()) { 1701 EXCEPTION_MARK; 1702 // Call method Thread.dispatchUncaughtException(). 1703 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1704 JavaValue result(T_VOID); 1705 JavaCalls::call_virtual(&result, 1706 threadObj, thread_klass, 1707 vmSymbols::dispatchUncaughtException_name(), 1708 vmSymbols::throwable_void_signature(), 1709 uncaught_exception, 1710 THREAD); 1711 if (HAS_PENDING_EXCEPTION) { 1712 ResourceMark rm(this); 1713 jio_fprintf(defaultStream::error_stream(), 1714 "\nException: %s thrown from the UncaughtExceptionHandler" 1715 " in thread \"%s\"\n", 1716 pending_exception()->klass()->external_name(), 1717 get_thread_name()); 1718 CLEAR_PENDING_EXCEPTION; 1719 } 1720 } 1721 1722 // Called before the java thread exit since we want to read info 1723 // from java_lang_Thread object 1724 EventThreadEnd event; 1725 if (event.should_commit()) { 1726 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1727 event.commit(); 1728 } 1729 1730 // Call after last event on thread 1731 EVENT_THREAD_EXIT(this); 1732 1733 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1734 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1735 // is deprecated anyhow. 1736 if (!is_Compiler_thread()) { 1737 int count = 3; 1738 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1739 EXCEPTION_MARK; 1740 JavaValue result(T_VOID); 1741 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1742 JavaCalls::call_virtual(&result, 1743 threadObj, thread_klass, 1744 vmSymbols::exit_method_name(), 1745 vmSymbols::void_method_signature(), 1746 THREAD); 1747 CLEAR_PENDING_EXCEPTION; 1748 } 1749 } 1750 // notify JVMTI 1751 if (JvmtiExport::should_post_thread_life()) { 1752 JvmtiExport::post_thread_end(this); 1753 } 1754 1755 // We have notified the agents that we are exiting, before we go on, 1756 // we must check for a pending external suspend request and honor it 1757 // in order to not surprise the thread that made the suspend request. 1758 while (true) { 1759 { 1760 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1761 if (!is_external_suspend()) { 1762 set_terminated(_thread_exiting); 1763 ThreadService::current_thread_exiting(this); 1764 break; 1765 } 1766 // Implied else: 1767 // Things get a little tricky here. We have a pending external 1768 // suspend request, but we are holding the SR_lock so we 1769 // can't just self-suspend. So we temporarily drop the lock 1770 // and then self-suspend. 1771 } 1772 1773 ThreadBlockInVM tbivm(this); 1774 java_suspend_self(); 1775 1776 // We're done with this suspend request, but we have to loop around 1777 // and check again. Eventually we will get SR_lock without a pending 1778 // external suspend request and will be able to mark ourselves as 1779 // exiting. 1780 } 1781 // no more external suspends are allowed at this point 1782 } else { 1783 // before_exit() has already posted JVMTI THREAD_END events 1784 } 1785 1786 // Notify waiters on thread object. This has to be done after exit() is called 1787 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1788 // group should have the destroyed bit set before waiters are notified). 1789 ensure_join(this); 1790 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1791 1792 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1793 // held by this thread must be released. A detach operation must only 1794 // get here if there are no Java frames on the stack. Therefore, any 1795 // owned monitors at this point MUST be JNI-acquired monitors which are 1796 // pre-inflated and in the monitor cache. 1797 // 1798 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1799 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1800 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1801 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1802 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1803 } 1804 1805 // These things needs to be done while we are still a Java Thread. Make sure that thread 1806 // is in a consistent state, in case GC happens 1807 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1808 1809 if (active_handles() != NULL) { 1810 JNIHandleBlock* block = active_handles(); 1811 set_active_handles(NULL); 1812 JNIHandleBlock::release_block(block); 1813 } 1814 1815 if (free_handle_block() != NULL) { 1816 JNIHandleBlock* block = free_handle_block(); 1817 set_free_handle_block(NULL); 1818 JNIHandleBlock::release_block(block); 1819 } 1820 1821 // These have to be removed while this is still a valid thread. 1822 remove_stack_guard_pages(); 1823 1824 if (UseTLAB) { 1825 tlab().make_parsable(true); // retire TLAB 1826 } 1827 1828 if (JvmtiEnv::environments_might_exist()) { 1829 JvmtiExport::cleanup_thread(this); 1830 } 1831 1832 // We must flush any deferred card marks before removing a thread from 1833 // the list of active threads. 1834 Universe::heap()->flush_deferred_store_barrier(this); 1835 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1836 1837 #if INCLUDE_ALL_GCS 1838 // We must flush the G1-related buffers before removing a thread 1839 // from the list of active threads. We must do this after any deferred 1840 // card marks have been flushed (above) so that any entries that are 1841 // added to the thread's dirty card queue as a result are not lost. 1842 if (UseG1GC) { 1843 flush_barrier_queues(); 1844 } 1845 #endif // INCLUDE_ALL_GCS 1846 1847 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1848 Threads::remove(this); 1849 } 1850 1851 #if INCLUDE_ALL_GCS 1852 // Flush G1-related queues. 1853 void JavaThread::flush_barrier_queues() { 1854 satb_mark_queue().flush(); 1855 dirty_card_queue().flush(); 1856 } 1857 1858 void JavaThread::initialize_queues() { 1859 assert(!SafepointSynchronize::is_at_safepoint(), 1860 "we should not be at a safepoint"); 1861 1862 ObjPtrQueue& satb_queue = satb_mark_queue(); 1863 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1864 // The SATB queue should have been constructed with its active 1865 // field set to false. 1866 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1867 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1868 // If we are creating the thread during a marking cycle, we should 1869 // set the active field of the SATB queue to true. 1870 if (satb_queue_set.is_active()) { 1871 satb_queue.set_active(true); 1872 } 1873 1874 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1875 // The dirty card queue should have been constructed with its 1876 // active field set to true. 1877 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1878 } 1879 #endif // INCLUDE_ALL_GCS 1880 1881 void JavaThread::cleanup_failed_attach_current_thread() { 1882 if (get_thread_profiler() != NULL) { 1883 get_thread_profiler()->disengage(); 1884 ResourceMark rm; 1885 get_thread_profiler()->print(get_thread_name()); 1886 } 1887 1888 if (active_handles() != NULL) { 1889 JNIHandleBlock* block = active_handles(); 1890 set_active_handles(NULL); 1891 JNIHandleBlock::release_block(block); 1892 } 1893 1894 if (free_handle_block() != NULL) { 1895 JNIHandleBlock* block = free_handle_block(); 1896 set_free_handle_block(NULL); 1897 JNIHandleBlock::release_block(block); 1898 } 1899 1900 // These have to be removed while this is still a valid thread. 1901 remove_stack_guard_pages(); 1902 1903 if (UseTLAB) { 1904 tlab().make_parsable(true); // retire TLAB, if any 1905 } 1906 1907 #if INCLUDE_ALL_GCS 1908 if (UseG1GC) { 1909 flush_barrier_queues(); 1910 } 1911 #endif // INCLUDE_ALL_GCS 1912 1913 Threads::remove(this); 1914 delete this; 1915 } 1916 1917 1918 1919 1920 JavaThread* JavaThread::active() { 1921 Thread* thread = ThreadLocalStorage::thread(); 1922 assert(thread != NULL, "just checking"); 1923 if (thread->is_Java_thread()) { 1924 return (JavaThread*) thread; 1925 } else { 1926 assert(thread->is_VM_thread(), "this must be a vm thread"); 1927 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1928 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1929 assert(ret->is_Java_thread(), "must be a Java thread"); 1930 return ret; 1931 } 1932 } 1933 1934 bool JavaThread::is_lock_owned(address adr) const { 1935 if (Thread::is_lock_owned(adr)) return true; 1936 1937 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1938 if (chunk->contains(adr)) return true; 1939 } 1940 1941 return false; 1942 } 1943 1944 1945 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1946 chunk->set_next(monitor_chunks()); 1947 set_monitor_chunks(chunk); 1948 } 1949 1950 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1951 guarantee(monitor_chunks() != NULL, "must be non empty"); 1952 if (monitor_chunks() == chunk) { 1953 set_monitor_chunks(chunk->next()); 1954 } else { 1955 MonitorChunk* prev = monitor_chunks(); 1956 while (prev->next() != chunk) prev = prev->next(); 1957 prev->set_next(chunk->next()); 1958 } 1959 } 1960 1961 // JVM support. 1962 1963 // Note: this function shouldn't block if it's called in 1964 // _thread_in_native_trans state (such as from 1965 // check_special_condition_for_native_trans()). 1966 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 1967 1968 if (has_last_Java_frame() && has_async_condition()) { 1969 // If we are at a polling page safepoint (not a poll return) 1970 // then we must defer async exception because live registers 1971 // will be clobbered by the exception path. Poll return is 1972 // ok because the call we a returning from already collides 1973 // with exception handling registers and so there is no issue. 1974 // (The exception handling path kills call result registers but 1975 // this is ok since the exception kills the result anyway). 1976 1977 if (is_at_poll_safepoint()) { 1978 // if the code we are returning to has deoptimized we must defer 1979 // the exception otherwise live registers get clobbered on the 1980 // exception path before deoptimization is able to retrieve them. 1981 // 1982 RegisterMap map(this, false); 1983 frame caller_fr = last_frame().sender(&map); 1984 assert(caller_fr.is_compiled_frame(), "what?"); 1985 if (caller_fr.is_deoptimized_frame()) { 1986 if (TraceExceptions) { 1987 ResourceMark rm; 1988 tty->print_cr("deferred async exception at compiled safepoint"); 1989 } 1990 return; 1991 } 1992 } 1993 } 1994 1995 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 1996 if (condition == _no_async_condition) { 1997 // Conditions have changed since has_special_runtime_exit_condition() 1998 // was called: 1999 // - if we were here only because of an external suspend request, 2000 // then that was taken care of above (or cancelled) so we are done 2001 // - if we were here because of another async request, then it has 2002 // been cleared between the has_special_runtime_exit_condition() 2003 // and now so again we are done 2004 return; 2005 } 2006 2007 // Check for pending async. exception 2008 if (_pending_async_exception != NULL) { 2009 // Only overwrite an already pending exception, if it is not a threadDeath. 2010 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2011 2012 // We cannot call Exceptions::_throw(...) here because we cannot block 2013 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2014 2015 if (TraceExceptions) { 2016 ResourceMark rm; 2017 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2018 if (has_last_Java_frame()) { 2019 frame f = last_frame(); 2020 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2021 } 2022 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2023 } 2024 _pending_async_exception = NULL; 2025 clear_has_async_exception(); 2026 } 2027 } 2028 2029 if (check_unsafe_error && 2030 condition == _async_unsafe_access_error && !has_pending_exception()) { 2031 condition = _no_async_condition; // done 2032 switch (thread_state()) { 2033 case _thread_in_vm: { 2034 JavaThread* THREAD = this; 2035 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2036 } 2037 case _thread_in_native: { 2038 ThreadInVMfromNative tiv(this); 2039 JavaThread* THREAD = this; 2040 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2041 } 2042 case _thread_in_Java: { 2043 ThreadInVMfromJava tiv(this); 2044 JavaThread* THREAD = this; 2045 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2046 } 2047 default: 2048 ShouldNotReachHere(); 2049 } 2050 } 2051 2052 assert(condition == _no_async_condition || has_pending_exception() || 2053 (!check_unsafe_error && condition == _async_unsafe_access_error), 2054 "must have handled the async condition, if no exception"); 2055 } 2056 2057 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2058 // 2059 // Check for pending external suspend. Internal suspend requests do 2060 // not use handle_special_runtime_exit_condition(). 2061 // If JNIEnv proxies are allowed, don't self-suspend if the target 2062 // thread is not the current thread. In older versions of jdbx, jdbx 2063 // threads could call into the VM with another thread's JNIEnv so we 2064 // can be here operating on behalf of a suspended thread (4432884). 2065 bool do_self_suspend = is_external_suspend_with_lock(); 2066 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2067 // 2068 // Because thread is external suspended the safepoint code will count 2069 // thread as at a safepoint. This can be odd because we can be here 2070 // as _thread_in_Java which would normally transition to _thread_blocked 2071 // at a safepoint. We would like to mark the thread as _thread_blocked 2072 // before calling java_suspend_self like all other callers of it but 2073 // we must then observe proper safepoint protocol. (We can't leave 2074 // _thread_blocked with a safepoint in progress). However we can be 2075 // here as _thread_in_native_trans so we can't use a normal transition 2076 // constructor/destructor pair because they assert on that type of 2077 // transition. We could do something like: 2078 // 2079 // JavaThreadState state = thread_state(); 2080 // set_thread_state(_thread_in_vm); 2081 // { 2082 // ThreadBlockInVM tbivm(this); 2083 // java_suspend_self() 2084 // } 2085 // set_thread_state(_thread_in_vm_trans); 2086 // if (safepoint) block; 2087 // set_thread_state(state); 2088 // 2089 // but that is pretty messy. Instead we just go with the way the 2090 // code has worked before and note that this is the only path to 2091 // java_suspend_self that doesn't put the thread in _thread_blocked 2092 // mode. 2093 2094 frame_anchor()->make_walkable(this); 2095 java_suspend_self(); 2096 2097 // We might be here for reasons in addition to the self-suspend request 2098 // so check for other async requests. 2099 } 2100 2101 if (check_asyncs) { 2102 check_and_handle_async_exceptions(); 2103 } 2104 } 2105 2106 void JavaThread::send_thread_stop(oop java_throwable) { 2107 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2108 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2109 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2110 2111 // Do not throw asynchronous exceptions against the compiler thread 2112 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2113 if (is_Compiler_thread()) return; 2114 2115 { 2116 // Actually throw the Throwable against the target Thread - however 2117 // only if there is no thread death exception installed already. 2118 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2119 // If the topmost frame is a runtime stub, then we are calling into 2120 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2121 // must deoptimize the caller before continuing, as the compiled exception handler table 2122 // may not be valid 2123 if (has_last_Java_frame()) { 2124 frame f = last_frame(); 2125 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2126 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2127 RegisterMap reg_map(this, UseBiasedLocking); 2128 frame compiled_frame = f.sender(®_map); 2129 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2130 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2131 } 2132 } 2133 } 2134 2135 // Set async. pending exception in thread. 2136 set_pending_async_exception(java_throwable); 2137 2138 if (TraceExceptions) { 2139 ResourceMark rm; 2140 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2141 } 2142 // for AbortVMOnException flag 2143 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2144 } 2145 } 2146 2147 2148 // Interrupt thread so it will wake up from a potential wait() 2149 Thread::interrupt(this); 2150 } 2151 2152 // External suspension mechanism. 2153 // 2154 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2155 // to any VM_locks and it is at a transition 2156 // Self-suspension will happen on the transition out of the vm. 2157 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2158 // 2159 // Guarantees on return: 2160 // + Target thread will not execute any new bytecode (that's why we need to 2161 // force a safepoint) 2162 // + Target thread will not enter any new monitors 2163 // 2164 void JavaThread::java_suspend() { 2165 { MutexLocker mu(Threads_lock); 2166 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2167 return; 2168 } 2169 } 2170 2171 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2172 if (!is_external_suspend()) { 2173 // a racing resume has cancelled us; bail out now 2174 return; 2175 } 2176 2177 // suspend is done 2178 uint32_t debug_bits = 0; 2179 // Warning: is_ext_suspend_completed() may temporarily drop the 2180 // SR_lock to allow the thread to reach a stable thread state if 2181 // it is currently in a transient thread state. 2182 if (is_ext_suspend_completed(false /* !called_by_wait */, 2183 SuspendRetryDelay, &debug_bits)) { 2184 return; 2185 } 2186 } 2187 2188 VM_ForceSafepoint vm_suspend; 2189 VMThread::execute(&vm_suspend); 2190 } 2191 2192 // Part II of external suspension. 2193 // A JavaThread self suspends when it detects a pending external suspend 2194 // request. This is usually on transitions. It is also done in places 2195 // where continuing to the next transition would surprise the caller, 2196 // e.g., monitor entry. 2197 // 2198 // Returns the number of times that the thread self-suspended. 2199 // 2200 // Note: DO NOT call java_suspend_self() when you just want to block current 2201 // thread. java_suspend_self() is the second stage of cooperative 2202 // suspension for external suspend requests and should only be used 2203 // to complete an external suspend request. 2204 // 2205 int JavaThread::java_suspend_self() { 2206 int ret = 0; 2207 2208 // we are in the process of exiting so don't suspend 2209 if (is_exiting()) { 2210 clear_external_suspend(); 2211 return ret; 2212 } 2213 2214 assert(_anchor.walkable() || 2215 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2216 "must have walkable stack"); 2217 2218 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2219 2220 assert(!this->is_ext_suspended(), 2221 "a thread trying to self-suspend should not already be suspended"); 2222 2223 if (this->is_suspend_equivalent()) { 2224 // If we are self-suspending as a result of the lifting of a 2225 // suspend equivalent condition, then the suspend_equivalent 2226 // flag is not cleared until we set the ext_suspended flag so 2227 // that wait_for_ext_suspend_completion() returns consistent 2228 // results. 2229 this->clear_suspend_equivalent(); 2230 } 2231 2232 // A racing resume may have cancelled us before we grabbed SR_lock 2233 // above. Or another external suspend request could be waiting for us 2234 // by the time we return from SR_lock()->wait(). The thread 2235 // that requested the suspension may already be trying to walk our 2236 // stack and if we return now, we can change the stack out from under 2237 // it. This would be a "bad thing (TM)" and cause the stack walker 2238 // to crash. We stay self-suspended until there are no more pending 2239 // external suspend requests. 2240 while (is_external_suspend()) { 2241 ret++; 2242 this->set_ext_suspended(); 2243 2244 // _ext_suspended flag is cleared by java_resume() 2245 while (is_ext_suspended()) { 2246 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2247 } 2248 } 2249 2250 return ret; 2251 } 2252 2253 #ifdef ASSERT 2254 // verify the JavaThread has not yet been published in the Threads::list, and 2255 // hence doesn't need protection from concurrent access at this stage 2256 void JavaThread::verify_not_published() { 2257 if (!Threads_lock->owned_by_self()) { 2258 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2259 assert(!Threads::includes(this), 2260 "java thread shouldn't have been published yet!"); 2261 } else { 2262 assert(!Threads::includes(this), 2263 "java thread shouldn't have been published yet!"); 2264 } 2265 } 2266 #endif 2267 2268 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2269 // progress or when _suspend_flags is non-zero. 2270 // Current thread needs to self-suspend if there is a suspend request and/or 2271 // block if a safepoint is in progress. 2272 // Async exception ISN'T checked. 2273 // Note only the ThreadInVMfromNative transition can call this function 2274 // directly and when thread state is _thread_in_native_trans 2275 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2276 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2277 2278 JavaThread *curJT = JavaThread::current(); 2279 bool do_self_suspend = thread->is_external_suspend(); 2280 2281 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2282 2283 // If JNIEnv proxies are allowed, don't self-suspend if the target 2284 // thread is not the current thread. In older versions of jdbx, jdbx 2285 // threads could call into the VM with another thread's JNIEnv so we 2286 // can be here operating on behalf of a suspended thread (4432884). 2287 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2288 JavaThreadState state = thread->thread_state(); 2289 2290 // We mark this thread_blocked state as a suspend-equivalent so 2291 // that a caller to is_ext_suspend_completed() won't be confused. 2292 // The suspend-equivalent state is cleared by java_suspend_self(). 2293 thread->set_suspend_equivalent(); 2294 2295 // If the safepoint code sees the _thread_in_native_trans state, it will 2296 // wait until the thread changes to other thread state. There is no 2297 // guarantee on how soon we can obtain the SR_lock and complete the 2298 // self-suspend request. It would be a bad idea to let safepoint wait for 2299 // too long. Temporarily change the state to _thread_blocked to 2300 // let the VM thread know that this thread is ready for GC. The problem 2301 // of changing thread state is that safepoint could happen just after 2302 // java_suspend_self() returns after being resumed, and VM thread will 2303 // see the _thread_blocked state. We must check for safepoint 2304 // after restoring the state and make sure we won't leave while a safepoint 2305 // is in progress. 2306 thread->set_thread_state(_thread_blocked); 2307 thread->java_suspend_self(); 2308 thread->set_thread_state(state); 2309 // Make sure new state is seen by VM thread 2310 if (os::is_MP()) { 2311 if (UseMembar) { 2312 // Force a fence between the write above and read below 2313 OrderAccess::fence(); 2314 } else { 2315 // Must use this rather than serialization page in particular on Windows 2316 InterfaceSupport::serialize_memory(thread); 2317 } 2318 } 2319 } 2320 2321 if (SafepointSynchronize::do_call_back()) { 2322 // If we are safepointing, then block the caller which may not be 2323 // the same as the target thread (see above). 2324 SafepointSynchronize::block(curJT); 2325 } 2326 2327 if (thread->is_deopt_suspend()) { 2328 thread->clear_deopt_suspend(); 2329 RegisterMap map(thread, false); 2330 frame f = thread->last_frame(); 2331 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2332 f = f.sender(&map); 2333 } 2334 if (f.id() == thread->must_deopt_id()) { 2335 thread->clear_must_deopt_id(); 2336 f.deoptimize(thread); 2337 } else { 2338 fatal("missed deoptimization!"); 2339 } 2340 } 2341 } 2342 2343 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2344 // progress or when _suspend_flags is non-zero. 2345 // Current thread needs to self-suspend if there is a suspend request and/or 2346 // block if a safepoint is in progress. 2347 // Also check for pending async exception (not including unsafe access error). 2348 // Note only the native==>VM/Java barriers can call this function and when 2349 // thread state is _thread_in_native_trans. 2350 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2351 check_safepoint_and_suspend_for_native_trans(thread); 2352 2353 if (thread->has_async_exception()) { 2354 // We are in _thread_in_native_trans state, don't handle unsafe 2355 // access error since that may block. 2356 thread->check_and_handle_async_exceptions(false); 2357 } 2358 } 2359 2360 // This is a variant of the normal 2361 // check_special_condition_for_native_trans with slightly different 2362 // semantics for use by critical native wrappers. It does all the 2363 // normal checks but also performs the transition back into 2364 // thread_in_Java state. This is required so that critical natives 2365 // can potentially block and perform a GC if they are the last thread 2366 // exiting the GC_locker. 2367 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2368 check_special_condition_for_native_trans(thread); 2369 2370 // Finish the transition 2371 thread->set_thread_state(_thread_in_Java); 2372 2373 if (thread->do_critical_native_unlock()) { 2374 ThreadInVMfromJavaNoAsyncException tiv(thread); 2375 GC_locker::unlock_critical(thread); 2376 thread->clear_critical_native_unlock(); 2377 } 2378 } 2379 2380 // We need to guarantee the Threads_lock here, since resumes are not 2381 // allowed during safepoint synchronization 2382 // Can only resume from an external suspension 2383 void JavaThread::java_resume() { 2384 assert_locked_or_safepoint(Threads_lock); 2385 2386 // Sanity check: thread is gone, has started exiting or the thread 2387 // was not externally suspended. 2388 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2389 return; 2390 } 2391 2392 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2393 2394 clear_external_suspend(); 2395 2396 if (is_ext_suspended()) { 2397 clear_ext_suspended(); 2398 SR_lock()->notify_all(); 2399 } 2400 } 2401 2402 void JavaThread::create_stack_guard_pages() { 2403 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2404 address low_addr = stack_base() - stack_size(); 2405 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2406 2407 int allocate = os::allocate_stack_guard_pages(); 2408 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2409 2410 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2411 warning("Attempt to allocate stack guard pages failed."); 2412 return; 2413 } 2414 2415 if (os::guard_memory((char *) low_addr, len)) { 2416 _stack_guard_state = stack_guard_enabled; 2417 } else { 2418 warning("Attempt to protect stack guard pages failed."); 2419 if (os::uncommit_memory((char *) low_addr, len)) { 2420 warning("Attempt to deallocate stack guard pages failed."); 2421 } 2422 } 2423 } 2424 2425 void JavaThread::remove_stack_guard_pages() { 2426 assert(Thread::current() == this, "from different thread"); 2427 if (_stack_guard_state == stack_guard_unused) return; 2428 address low_addr = stack_base() - stack_size(); 2429 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2430 2431 if (os::allocate_stack_guard_pages()) { 2432 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2433 _stack_guard_state = stack_guard_unused; 2434 } else { 2435 warning("Attempt to deallocate stack guard pages failed."); 2436 } 2437 } else { 2438 if (_stack_guard_state == stack_guard_unused) return; 2439 if (os::unguard_memory((char *) low_addr, len)) { 2440 _stack_guard_state = stack_guard_unused; 2441 } else { 2442 warning("Attempt to unprotect stack guard pages failed."); 2443 } 2444 } 2445 } 2446 2447 void JavaThread::enable_stack_yellow_zone() { 2448 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2449 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2450 2451 // The base notation is from the stacks point of view, growing downward. 2452 // We need to adjust it to work correctly with guard_memory() 2453 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2454 2455 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2456 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2457 2458 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2459 _stack_guard_state = stack_guard_enabled; 2460 } else { 2461 warning("Attempt to guard stack yellow zone failed."); 2462 } 2463 enable_register_stack_guard(); 2464 } 2465 2466 void JavaThread::disable_stack_yellow_zone() { 2467 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2468 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2469 2470 // Simply return if called for a thread that does not use guard pages. 2471 if (_stack_guard_state == stack_guard_unused) return; 2472 2473 // The base notation is from the stacks point of view, growing downward. 2474 // We need to adjust it to work correctly with guard_memory() 2475 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2476 2477 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2478 _stack_guard_state = stack_guard_yellow_disabled; 2479 } else { 2480 warning("Attempt to unguard stack yellow zone failed."); 2481 } 2482 disable_register_stack_guard(); 2483 } 2484 2485 void JavaThread::enable_stack_red_zone() { 2486 // The base notation is from the stacks point of view, growing downward. 2487 // We need to adjust it to work correctly with guard_memory() 2488 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2489 address base = stack_red_zone_base() - stack_red_zone_size(); 2490 2491 guarantee(base < stack_base(), "Error calculating stack red zone"); 2492 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2493 2494 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2495 warning("Attempt to guard stack red zone failed."); 2496 } 2497 } 2498 2499 void JavaThread::disable_stack_red_zone() { 2500 // The base notation is from the stacks point of view, growing downward. 2501 // We need to adjust it to work correctly with guard_memory() 2502 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2503 address base = stack_red_zone_base() - stack_red_zone_size(); 2504 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2505 warning("Attempt to unguard stack red zone failed."); 2506 } 2507 } 2508 2509 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2510 // ignore is there is no stack 2511 if (!has_last_Java_frame()) return; 2512 // traverse the stack frames. Starts from top frame. 2513 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2514 frame* fr = fst.current(); 2515 f(fr, fst.register_map()); 2516 } 2517 } 2518 2519 2520 #ifndef PRODUCT 2521 // Deoptimization 2522 // Function for testing deoptimization 2523 void JavaThread::deoptimize() { 2524 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2525 StackFrameStream fst(this, UseBiasedLocking); 2526 bool deopt = false; // Dump stack only if a deopt actually happens. 2527 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2528 // Iterate over all frames in the thread and deoptimize 2529 for (; !fst.is_done(); fst.next()) { 2530 if (fst.current()->can_be_deoptimized()) { 2531 2532 if (only_at) { 2533 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2534 // consists of comma or carriage return separated numbers so 2535 // search for the current bci in that string. 2536 address pc = fst.current()->pc(); 2537 nmethod* nm = (nmethod*) fst.current()->cb(); 2538 ScopeDesc* sd = nm->scope_desc_at(pc); 2539 char buffer[8]; 2540 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2541 size_t len = strlen(buffer); 2542 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2543 while (found != NULL) { 2544 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2545 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2546 // Check that the bci found is bracketed by terminators. 2547 break; 2548 } 2549 found = strstr(found + 1, buffer); 2550 } 2551 if (!found) { 2552 continue; 2553 } 2554 } 2555 2556 if (DebugDeoptimization && !deopt) { 2557 deopt = true; // One-time only print before deopt 2558 tty->print_cr("[BEFORE Deoptimization]"); 2559 trace_frames(); 2560 trace_stack(); 2561 } 2562 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2563 } 2564 } 2565 2566 if (DebugDeoptimization && deopt) { 2567 tty->print_cr("[AFTER Deoptimization]"); 2568 trace_frames(); 2569 } 2570 } 2571 2572 2573 // Make zombies 2574 void JavaThread::make_zombies() { 2575 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2576 if (fst.current()->can_be_deoptimized()) { 2577 // it is a Java nmethod 2578 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2579 nm->make_not_entrant(); 2580 } 2581 } 2582 } 2583 #endif // PRODUCT 2584 2585 2586 void JavaThread::deoptimized_wrt_marked_nmethods() { 2587 if (!has_last_Java_frame()) return; 2588 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2589 StackFrameStream fst(this, UseBiasedLocking); 2590 for (; !fst.is_done(); fst.next()) { 2591 if (fst.current()->should_be_deoptimized()) { 2592 if (LogCompilation && xtty != NULL) { 2593 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2594 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2595 this->name(), nm != NULL ? nm->compile_id() : -1); 2596 } 2597 2598 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2599 } 2600 } 2601 } 2602 2603 2604 // If the caller is a NamedThread, then remember, in the current scope, 2605 // the given JavaThread in its _processed_thread field. 2606 class RememberProcessedThread: public StackObj { 2607 NamedThread* _cur_thr; 2608 public: 2609 RememberProcessedThread(JavaThread* jthr) { 2610 Thread* thread = Thread::current(); 2611 if (thread->is_Named_thread()) { 2612 _cur_thr = (NamedThread *)thread; 2613 _cur_thr->set_processed_thread(jthr); 2614 } else { 2615 _cur_thr = NULL; 2616 } 2617 } 2618 2619 ~RememberProcessedThread() { 2620 if (_cur_thr) { 2621 _cur_thr->set_processed_thread(NULL); 2622 } 2623 } 2624 }; 2625 2626 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2627 // Verify that the deferred card marks have been flushed. 2628 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2629 2630 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2631 // since there may be more than one thread using each ThreadProfiler. 2632 2633 // Traverse the GCHandles 2634 Thread::oops_do(f, cld_f, cf); 2635 2636 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2637 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2638 2639 if (has_last_Java_frame()) { 2640 // Record JavaThread to GC thread 2641 RememberProcessedThread rpt(this); 2642 2643 // Traverse the privileged stack 2644 if (_privileged_stack_top != NULL) { 2645 _privileged_stack_top->oops_do(f); 2646 } 2647 2648 // traverse the registered growable array 2649 if (_array_for_gc != NULL) { 2650 for (int index = 0; index < _array_for_gc->length(); index++) { 2651 f->do_oop(_array_for_gc->adr_at(index)); 2652 } 2653 } 2654 2655 // Traverse the monitor chunks 2656 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2657 chunk->oops_do(f); 2658 } 2659 2660 // Traverse the execution stack 2661 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2662 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2663 } 2664 } 2665 2666 // callee_target is never live across a gc point so NULL it here should 2667 // it still contain a methdOop. 2668 2669 set_callee_target(NULL); 2670 2671 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2672 // If we have deferred set_locals there might be oops waiting to be 2673 // written 2674 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2675 if (list != NULL) { 2676 for (int i = 0; i < list->length(); i++) { 2677 list->at(i)->oops_do(f); 2678 } 2679 } 2680 2681 // Traverse instance variables at the end since the GC may be moving things 2682 // around using this function 2683 f->do_oop((oop*) &_threadObj); 2684 f->do_oop((oop*) &_vm_result); 2685 f->do_oop((oop*) &_exception_oop); 2686 f->do_oop((oop*) &_pending_async_exception); 2687 2688 if (jvmti_thread_state() != NULL) { 2689 jvmti_thread_state()->oops_do(f); 2690 } 2691 } 2692 2693 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2694 Thread::nmethods_do(cf); // (super method is a no-op) 2695 2696 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2697 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2698 2699 if (has_last_Java_frame()) { 2700 // Traverse the execution stack 2701 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2702 fst.current()->nmethods_do(cf); 2703 } 2704 } 2705 } 2706 2707 void JavaThread::metadata_do(void f(Metadata*)) { 2708 Thread::metadata_do(f); 2709 if (has_last_Java_frame()) { 2710 // Traverse the execution stack to call f() on the methods in the stack 2711 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2712 fst.current()->metadata_do(f); 2713 } 2714 } else if (is_Compiler_thread()) { 2715 // need to walk ciMetadata in current compile tasks to keep alive. 2716 CompilerThread* ct = (CompilerThread*)this; 2717 if (ct->env() != NULL) { 2718 ct->env()->metadata_do(f); 2719 } 2720 } 2721 } 2722 2723 // Printing 2724 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2725 switch (_thread_state) { 2726 case _thread_uninitialized: return "_thread_uninitialized"; 2727 case _thread_new: return "_thread_new"; 2728 case _thread_new_trans: return "_thread_new_trans"; 2729 case _thread_in_native: return "_thread_in_native"; 2730 case _thread_in_native_trans: return "_thread_in_native_trans"; 2731 case _thread_in_vm: return "_thread_in_vm"; 2732 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2733 case _thread_in_Java: return "_thread_in_Java"; 2734 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2735 case _thread_blocked: return "_thread_blocked"; 2736 case _thread_blocked_trans: return "_thread_blocked_trans"; 2737 default: return "unknown thread state"; 2738 } 2739 } 2740 2741 #ifndef PRODUCT 2742 void JavaThread::print_thread_state_on(outputStream *st) const { 2743 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2744 }; 2745 void JavaThread::print_thread_state() const { 2746 print_thread_state_on(tty); 2747 } 2748 #endif // PRODUCT 2749 2750 // Called by Threads::print() for VM_PrintThreads operation 2751 void JavaThread::print_on(outputStream *st) const { 2752 st->print("\"%s\" ", get_thread_name()); 2753 oop thread_oop = threadObj(); 2754 if (thread_oop != NULL) { 2755 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2756 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2757 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2758 } 2759 Thread::print_on(st); 2760 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2761 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2762 if (thread_oop != NULL) { 2763 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2764 } 2765 #ifndef PRODUCT 2766 print_thread_state_on(st); 2767 _safepoint_state->print_on(st); 2768 #endif // PRODUCT 2769 } 2770 2771 // Called by fatal error handler. The difference between this and 2772 // JavaThread::print() is that we can't grab lock or allocate memory. 2773 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2774 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2775 oop thread_obj = threadObj(); 2776 if (thread_obj != NULL) { 2777 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2778 } 2779 st->print(" ["); 2780 st->print("%s", _get_thread_state_name(_thread_state)); 2781 if (osthread()) { 2782 st->print(", id=%d", osthread()->thread_id()); 2783 } 2784 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2785 _stack_base - _stack_size, _stack_base); 2786 st->print("]"); 2787 return; 2788 } 2789 2790 // Verification 2791 2792 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2793 2794 void JavaThread::verify() { 2795 // Verify oops in the thread. 2796 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2797 2798 // Verify the stack frames. 2799 frames_do(frame_verify); 2800 } 2801 2802 // CR 6300358 (sub-CR 2137150) 2803 // Most callers of this method assume that it can't return NULL but a 2804 // thread may not have a name whilst it is in the process of attaching to 2805 // the VM - see CR 6412693, and there are places where a JavaThread can be 2806 // seen prior to having it's threadObj set (eg JNI attaching threads and 2807 // if vm exit occurs during initialization). These cases can all be accounted 2808 // for such that this method never returns NULL. 2809 const char* JavaThread::get_thread_name() const { 2810 #ifdef ASSERT 2811 // early safepoints can hit while current thread does not yet have TLS 2812 if (!SafepointSynchronize::is_at_safepoint()) { 2813 Thread *cur = Thread::current(); 2814 if (!(cur->is_Java_thread() && cur == this)) { 2815 // Current JavaThreads are allowed to get their own name without 2816 // the Threads_lock. 2817 assert_locked_or_safepoint(Threads_lock); 2818 } 2819 } 2820 #endif // ASSERT 2821 return get_thread_name_string(); 2822 } 2823 2824 // Returns a non-NULL representation of this thread's name, or a suitable 2825 // descriptive string if there is no set name 2826 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2827 const char* name_str; 2828 oop thread_obj = threadObj(); 2829 if (thread_obj != NULL) { 2830 oop name = java_lang_Thread::name(thread_obj); 2831 if (name != NULL) { 2832 if (buf == NULL) { 2833 name_str = java_lang_String::as_utf8_string(name); 2834 } else { 2835 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 2836 } 2837 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2838 name_str = "<no-name - thread is attaching>"; 2839 } else { 2840 name_str = Thread::name(); 2841 } 2842 } else { 2843 name_str = Thread::name(); 2844 } 2845 assert(name_str != NULL, "unexpected NULL thread name"); 2846 return name_str; 2847 } 2848 2849 2850 const char* JavaThread::get_threadgroup_name() const { 2851 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2852 oop thread_obj = threadObj(); 2853 if (thread_obj != NULL) { 2854 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2855 if (thread_group != NULL) { 2856 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2857 // ThreadGroup.name can be null 2858 if (name != NULL) { 2859 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2860 return str; 2861 } 2862 } 2863 } 2864 return NULL; 2865 } 2866 2867 const char* JavaThread::get_parent_name() const { 2868 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2869 oop thread_obj = threadObj(); 2870 if (thread_obj != NULL) { 2871 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2872 if (thread_group != NULL) { 2873 oop parent = java_lang_ThreadGroup::parent(thread_group); 2874 if (parent != NULL) { 2875 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2876 // ThreadGroup.name can be null 2877 if (name != NULL) { 2878 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2879 return str; 2880 } 2881 } 2882 } 2883 } 2884 return NULL; 2885 } 2886 2887 ThreadPriority JavaThread::java_priority() const { 2888 oop thr_oop = threadObj(); 2889 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2890 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2891 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2892 return priority; 2893 } 2894 2895 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2896 2897 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2898 // Link Java Thread object <-> C++ Thread 2899 2900 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2901 // and put it into a new Handle. The Handle "thread_oop" can then 2902 // be used to pass the C++ thread object to other methods. 2903 2904 // Set the Java level thread object (jthread) field of the 2905 // new thread (a JavaThread *) to C++ thread object using the 2906 // "thread_oop" handle. 2907 2908 // Set the thread field (a JavaThread *) of the 2909 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2910 2911 Handle thread_oop(Thread::current(), 2912 JNIHandles::resolve_non_null(jni_thread)); 2913 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 2914 "must be initialized"); 2915 set_threadObj(thread_oop()); 2916 java_lang_Thread::set_thread(thread_oop(), this); 2917 2918 if (prio == NoPriority) { 2919 prio = java_lang_Thread::priority(thread_oop()); 2920 assert(prio != NoPriority, "A valid priority should be present"); 2921 } 2922 2923 // Push the Java priority down to the native thread; needs Threads_lock 2924 Thread::set_priority(this, prio); 2925 2926 prepare_ext(); 2927 2928 // Add the new thread to the Threads list and set it in motion. 2929 // We must have threads lock in order to call Threads::add. 2930 // It is crucial that we do not block before the thread is 2931 // added to the Threads list for if a GC happens, then the java_thread oop 2932 // will not be visited by GC. 2933 Threads::add(this); 2934 } 2935 2936 oop JavaThread::current_park_blocker() { 2937 // Support for JSR-166 locks 2938 oop thread_oop = threadObj(); 2939 if (thread_oop != NULL && 2940 JDK_Version::current().supports_thread_park_blocker()) { 2941 return java_lang_Thread::park_blocker(thread_oop); 2942 } 2943 return NULL; 2944 } 2945 2946 2947 void JavaThread::print_stack_on(outputStream* st) { 2948 if (!has_last_Java_frame()) return; 2949 ResourceMark rm; 2950 HandleMark hm; 2951 2952 RegisterMap reg_map(this); 2953 vframe* start_vf = last_java_vframe(®_map); 2954 int count = 0; 2955 for (vframe* f = start_vf; f; f = f->sender()) { 2956 if (f->is_java_frame()) { 2957 javaVFrame* jvf = javaVFrame::cast(f); 2958 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 2959 2960 // Print out lock information 2961 if (JavaMonitorsInStackTrace) { 2962 jvf->print_lock_info_on(st, count); 2963 } 2964 } else { 2965 // Ignore non-Java frames 2966 } 2967 2968 // Bail-out case for too deep stacks 2969 count++; 2970 if (MaxJavaStackTraceDepth == count) return; 2971 } 2972 } 2973 2974 2975 // JVMTI PopFrame support 2976 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 2977 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 2978 if (in_bytes(size_in_bytes) != 0) { 2979 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 2980 _popframe_preserved_args_size = in_bytes(size_in_bytes); 2981 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 2982 } 2983 } 2984 2985 void* JavaThread::popframe_preserved_args() { 2986 return _popframe_preserved_args; 2987 } 2988 2989 ByteSize JavaThread::popframe_preserved_args_size() { 2990 return in_ByteSize(_popframe_preserved_args_size); 2991 } 2992 2993 WordSize JavaThread::popframe_preserved_args_size_in_words() { 2994 int sz = in_bytes(popframe_preserved_args_size()); 2995 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 2996 return in_WordSize(sz / wordSize); 2997 } 2998 2999 void JavaThread::popframe_free_preserved_args() { 3000 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3001 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3002 _popframe_preserved_args = NULL; 3003 _popframe_preserved_args_size = 0; 3004 } 3005 3006 #ifndef PRODUCT 3007 3008 void JavaThread::trace_frames() { 3009 tty->print_cr("[Describe stack]"); 3010 int frame_no = 1; 3011 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3012 tty->print(" %d. ", frame_no++); 3013 fst.current()->print_value_on(tty, this); 3014 tty->cr(); 3015 } 3016 } 3017 3018 class PrintAndVerifyOopClosure: public OopClosure { 3019 protected: 3020 template <class T> inline void do_oop_work(T* p) { 3021 oop obj = oopDesc::load_decode_heap_oop(p); 3022 if (obj == NULL) return; 3023 tty->print(INTPTR_FORMAT ": ", p); 3024 if (obj->is_oop_or_null()) { 3025 if (obj->is_objArray()) { 3026 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3027 } else { 3028 obj->print(); 3029 } 3030 } else { 3031 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3032 } 3033 tty->cr(); 3034 } 3035 public: 3036 virtual void do_oop(oop* p) { do_oop_work(p); } 3037 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3038 }; 3039 3040 3041 static void oops_print(frame* f, const RegisterMap *map) { 3042 PrintAndVerifyOopClosure print; 3043 f->print_value(); 3044 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3045 } 3046 3047 // Print our all the locations that contain oops and whether they are 3048 // valid or not. This useful when trying to find the oldest frame 3049 // where an oop has gone bad since the frame walk is from youngest to 3050 // oldest. 3051 void JavaThread::trace_oops() { 3052 tty->print_cr("[Trace oops]"); 3053 frames_do(oops_print); 3054 } 3055 3056 3057 #ifdef ASSERT 3058 // Print or validate the layout of stack frames 3059 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3060 ResourceMark rm; 3061 PRESERVE_EXCEPTION_MARK; 3062 FrameValues values; 3063 int frame_no = 0; 3064 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3065 fst.current()->describe(values, ++frame_no); 3066 if (depth == frame_no) break; 3067 } 3068 if (validate_only) { 3069 values.validate(); 3070 } else { 3071 tty->print_cr("[Describe stack layout]"); 3072 values.print(this); 3073 } 3074 } 3075 #endif 3076 3077 void JavaThread::trace_stack_from(vframe* start_vf) { 3078 ResourceMark rm; 3079 int vframe_no = 1; 3080 for (vframe* f = start_vf; f; f = f->sender()) { 3081 if (f->is_java_frame()) { 3082 javaVFrame::cast(f)->print_activation(vframe_no++); 3083 } else { 3084 f->print(); 3085 } 3086 if (vframe_no > StackPrintLimit) { 3087 tty->print_cr("...<more frames>..."); 3088 return; 3089 } 3090 } 3091 } 3092 3093 3094 void JavaThread::trace_stack() { 3095 if (!has_last_Java_frame()) return; 3096 ResourceMark rm; 3097 HandleMark hm; 3098 RegisterMap reg_map(this); 3099 trace_stack_from(last_java_vframe(®_map)); 3100 } 3101 3102 3103 #endif // PRODUCT 3104 3105 3106 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3107 assert(reg_map != NULL, "a map must be given"); 3108 frame f = last_frame(); 3109 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3110 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3111 } 3112 return NULL; 3113 } 3114 3115 3116 Klass* JavaThread::security_get_caller_class(int depth) { 3117 vframeStream vfst(this); 3118 vfst.security_get_caller_frame(depth); 3119 if (!vfst.at_end()) { 3120 return vfst.method()->method_holder(); 3121 } 3122 return NULL; 3123 } 3124 3125 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3126 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3127 CompileBroker::compiler_thread_loop(); 3128 } 3129 3130 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3131 NMethodSweeper::sweeper_loop(); 3132 } 3133 3134 // Create a CompilerThread 3135 CompilerThread::CompilerThread(CompileQueue* queue, 3136 CompilerCounters* counters) 3137 : JavaThread(&compiler_thread_entry) { 3138 _env = NULL; 3139 _log = NULL; 3140 _task = NULL; 3141 _queue = queue; 3142 _counters = counters; 3143 _buffer_blob = NULL; 3144 _compiler = NULL; 3145 3146 #ifndef PRODUCT 3147 _ideal_graph_printer = NULL; 3148 #endif 3149 } 3150 3151 // Create sweeper thread 3152 CodeCacheSweeperThread::CodeCacheSweeperThread() 3153 : JavaThread(&sweeper_thread_entry) { 3154 _scanned_nmethod = NULL; 3155 } 3156 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3157 JavaThread::oops_do(f, cld_f, cf); 3158 if (_scanned_nmethod != NULL && cf != NULL) { 3159 // Safepoints can occur when the sweeper is scanning an nmethod so 3160 // process it here to make sure it isn't unloaded in the middle of 3161 // a scan. 3162 cf->do_code_blob(_scanned_nmethod); 3163 } 3164 } 3165 3166 3167 // ======= Threads ======== 3168 3169 // The Threads class links together all active threads, and provides 3170 // operations over all threads. It is protected by its own Mutex 3171 // lock, which is also used in other contexts to protect thread 3172 // operations from having the thread being operated on from exiting 3173 // and going away unexpectedly (e.g., safepoint synchronization) 3174 3175 JavaThread* Threads::_thread_list = NULL; 3176 int Threads::_number_of_threads = 0; 3177 int Threads::_number_of_non_daemon_threads = 0; 3178 int Threads::_return_code = 0; 3179 size_t JavaThread::_stack_size_at_create = 0; 3180 #ifdef ASSERT 3181 bool Threads::_vm_complete = false; 3182 #endif 3183 3184 // All JavaThreads 3185 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3186 3187 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3188 void Threads::threads_do(ThreadClosure* tc) { 3189 assert_locked_or_safepoint(Threads_lock); 3190 // ALL_JAVA_THREADS iterates through all JavaThreads 3191 ALL_JAVA_THREADS(p) { 3192 tc->do_thread(p); 3193 } 3194 // Someday we could have a table or list of all non-JavaThreads. 3195 // For now, just manually iterate through them. 3196 tc->do_thread(VMThread::vm_thread()); 3197 Universe::heap()->gc_threads_do(tc); 3198 WatcherThread *wt = WatcherThread::watcher_thread(); 3199 // Strictly speaking, the following NULL check isn't sufficient to make sure 3200 // the data for WatcherThread is still valid upon being examined. However, 3201 // considering that WatchThread terminates when the VM is on the way to 3202 // exit at safepoint, the chance of the above is extremely small. The right 3203 // way to prevent termination of WatcherThread would be to acquire 3204 // Terminator_lock, but we can't do that without violating the lock rank 3205 // checking in some cases. 3206 if (wt != NULL) { 3207 tc->do_thread(wt); 3208 } 3209 3210 // If CompilerThreads ever become non-JavaThreads, add them here 3211 } 3212 3213 3214 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3215 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3216 3217 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3218 create_vm_init_libraries(); 3219 } 3220 3221 initialize_class(vmSymbols::java_lang_String(), CHECK); 3222 3223 // Initialize java_lang.System (needed before creating the thread) 3224 initialize_class(vmSymbols::java_lang_System(), CHECK); 3225 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3226 Handle thread_group = create_initial_thread_group(CHECK); 3227 Universe::set_main_thread_group(thread_group()); 3228 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3229 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3230 main_thread->set_threadObj(thread_object); 3231 // Set thread status to running since main thread has 3232 // been started and running. 3233 java_lang_Thread::set_thread_status(thread_object, 3234 java_lang_Thread::RUNNABLE); 3235 3236 // The VM creates & returns objects of this class. Make sure it's initialized. 3237 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3238 3239 // The VM preresolves methods to these classes. Make sure that they get initialized 3240 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3241 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3242 call_initializeSystemClass(CHECK); 3243 3244 // get the Java runtime name after java.lang.System is initialized 3245 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3246 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3247 3248 // an instance of OutOfMemory exception has been allocated earlier 3249 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3250 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3251 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3252 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3253 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3254 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3255 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3256 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3257 } 3258 3259 void Threads::initialize_jsr292_core_classes(TRAPS) { 3260 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3261 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3262 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3263 } 3264 3265 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3266 extern void JDK_Version_init(); 3267 3268 // Check version 3269 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3270 3271 // Initialize the output stream module 3272 ostream_init(); 3273 3274 // Process java launcher properties. 3275 Arguments::process_sun_java_launcher_properties(args); 3276 3277 // Initialize the os module before using TLS 3278 os::init(); 3279 3280 // Initialize system properties. 3281 Arguments::init_system_properties(); 3282 3283 // So that JDK version can be used as a discriminator when parsing arguments 3284 JDK_Version_init(); 3285 3286 // Update/Initialize System properties after JDK version number is known 3287 Arguments::init_version_specific_system_properties(); 3288 3289 // Parse arguments 3290 jint parse_result = Arguments::parse(args); 3291 if (parse_result != JNI_OK) return parse_result; 3292 3293 os::init_before_ergo(); 3294 3295 jint ergo_result = Arguments::apply_ergo(); 3296 if (ergo_result != JNI_OK) return ergo_result; 3297 3298 if (PauseAtStartup) { 3299 os::pause(); 3300 } 3301 3302 HOTSPOT_VM_INIT_BEGIN(); 3303 3304 // Record VM creation timing statistics 3305 TraceVmCreationTime create_vm_timer; 3306 create_vm_timer.start(); 3307 3308 // Timing (must come after argument parsing) 3309 TraceTime timer("Create VM", TraceStartupTime); 3310 3311 // Initialize the os module after parsing the args 3312 jint os_init_2_result = os::init_2(); 3313 if (os_init_2_result != JNI_OK) return os_init_2_result; 3314 3315 jint adjust_after_os_result = Arguments::adjust_after_os(); 3316 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3317 3318 // initialize TLS 3319 ThreadLocalStorage::init(); 3320 3321 // Initialize output stream logging 3322 ostream_init_log(); 3323 3324 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3325 // Must be before create_vm_init_agents() 3326 if (Arguments::init_libraries_at_startup()) { 3327 convert_vm_init_libraries_to_agents(); 3328 } 3329 3330 // Launch -agentlib/-agentpath and converted -Xrun agents 3331 if (Arguments::init_agents_at_startup()) { 3332 create_vm_init_agents(); 3333 } 3334 3335 // Initialize Threads state 3336 _thread_list = NULL; 3337 _number_of_threads = 0; 3338 _number_of_non_daemon_threads = 0; 3339 3340 // Initialize global data structures and create system classes in heap 3341 vm_init_globals(); 3342 3343 // Attach the main thread to this os thread 3344 JavaThread* main_thread = new JavaThread(); 3345 main_thread->set_thread_state(_thread_in_vm); 3346 // must do this before set_active_handles and initialize_thread_local_storage 3347 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3348 // change the stack size recorded here to one based on the java thread 3349 // stacksize. This adjusted size is what is used to figure the placement 3350 // of the guard pages. 3351 main_thread->record_stack_base_and_size(); 3352 main_thread->initialize_thread_local_storage(); 3353 3354 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3355 3356 if (!main_thread->set_as_starting_thread()) { 3357 vm_shutdown_during_initialization( 3358 "Failed necessary internal allocation. Out of swap space"); 3359 delete main_thread; 3360 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3361 return JNI_ENOMEM; 3362 } 3363 3364 // Enable guard page *after* os::create_main_thread(), otherwise it would 3365 // crash Linux VM, see notes in os_linux.cpp. 3366 main_thread->create_stack_guard_pages(); 3367 3368 // Initialize Java-Level synchronization subsystem 3369 ObjectMonitor::Initialize(); 3370 3371 // Initialize global modules 3372 jint status = init_globals(); 3373 if (status != JNI_OK) { 3374 delete main_thread; 3375 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3376 return status; 3377 } 3378 3379 // Should be done after the heap is fully created 3380 main_thread->cache_global_variables(); 3381 3382 HandleMark hm; 3383 3384 { MutexLocker mu(Threads_lock); 3385 Threads::add(main_thread); 3386 } 3387 3388 // Any JVMTI raw monitors entered in onload will transition into 3389 // real raw monitor. VM is setup enough here for raw monitor enter. 3390 JvmtiExport::transition_pending_onload_raw_monitors(); 3391 3392 // Create the VMThread 3393 { TraceTime timer("Start VMThread", TraceStartupTime); 3394 VMThread::create(); 3395 Thread* vmthread = VMThread::vm_thread(); 3396 3397 if (!os::create_thread(vmthread, os::vm_thread)) { 3398 vm_exit_during_initialization("Cannot create VM thread. " 3399 "Out of system resources."); 3400 } 3401 3402 // Wait for the VM thread to become ready, and VMThread::run to initialize 3403 // Monitors can have spurious returns, must always check another state flag 3404 { 3405 MutexLocker ml(Notify_lock); 3406 os::start_thread(vmthread); 3407 while (vmthread->active_handles() == NULL) { 3408 Notify_lock->wait(); 3409 } 3410 } 3411 } 3412 3413 assert(Universe::is_fully_initialized(), "not initialized"); 3414 if (VerifyDuringStartup) { 3415 // Make sure we're starting with a clean slate. 3416 VM_Verify verify_op; 3417 VMThread::execute(&verify_op); 3418 } 3419 3420 Thread* THREAD = Thread::current(); 3421 3422 // At this point, the Universe is initialized, but we have not executed 3423 // any byte code. Now is a good time (the only time) to dump out the 3424 // internal state of the JVM for sharing. 3425 if (DumpSharedSpaces) { 3426 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3427 ShouldNotReachHere(); 3428 } 3429 3430 // Always call even when there are not JVMTI environments yet, since environments 3431 // may be attached late and JVMTI must track phases of VM execution 3432 JvmtiExport::enter_start_phase(); 3433 3434 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3435 JvmtiExport::post_vm_start(); 3436 3437 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3438 3439 // We need this for ClassDataSharing - the initial vm.info property is set 3440 // with the default value of CDS "sharing" which may be reset through 3441 // command line options. 3442 reset_vm_info_property(CHECK_JNI_ERR); 3443 3444 quicken_jni_functions(); 3445 3446 // Must be run after init_ft which initializes ft_enabled 3447 if (TRACE_INITIALIZE() != JNI_OK) { 3448 vm_exit_during_initialization("Failed to initialize tracing backend"); 3449 } 3450 3451 // Set flag that basic initialization has completed. Used by exceptions and various 3452 // debug stuff, that does not work until all basic classes have been initialized. 3453 set_init_completed(); 3454 3455 Metaspace::post_initialize(); 3456 3457 HOTSPOT_VM_INIT_END(); 3458 3459 // record VM initialization completion time 3460 #if INCLUDE_MANAGEMENT 3461 Management::record_vm_init_completed(); 3462 #endif // INCLUDE_MANAGEMENT 3463 3464 // Compute system loader. Note that this has to occur after set_init_completed, since 3465 // valid exceptions may be thrown in the process. 3466 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3467 // set_init_completed has just been called, causing exceptions not to be shortcut 3468 // anymore. We call vm_exit_during_initialization directly instead. 3469 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR); 3470 3471 #if INCLUDE_ALL_GCS 3472 // Support for ConcurrentMarkSweep. This should be cleaned up 3473 // and better encapsulated. The ugly nested if test would go away 3474 // once things are properly refactored. XXX YSR 3475 if (UseConcMarkSweepGC || UseG1GC) { 3476 if (UseConcMarkSweepGC) { 3477 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3478 } else { 3479 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3480 } 3481 } 3482 #endif // INCLUDE_ALL_GCS 3483 3484 // Always call even when there are not JVMTI environments yet, since environments 3485 // may be attached late and JVMTI must track phases of VM execution 3486 JvmtiExport::enter_live_phase(); 3487 3488 // Signal Dispatcher needs to be started before VMInit event is posted 3489 os::signal_init(); 3490 3491 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3492 if (!DisableAttachMechanism) { 3493 AttachListener::vm_start(); 3494 if (StartAttachListener || AttachListener::init_at_startup()) { 3495 AttachListener::init(); 3496 } 3497 } 3498 3499 // Launch -Xrun agents 3500 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3501 // back-end can launch with -Xdebug -Xrunjdwp. 3502 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3503 create_vm_init_libraries(); 3504 } 3505 3506 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3507 JvmtiExport::post_vm_initialized(); 3508 3509 if (TRACE_START() != JNI_OK) { 3510 vm_exit_during_initialization("Failed to start tracing backend."); 3511 } 3512 3513 if (CleanChunkPoolAsync) { 3514 Chunk::start_chunk_pool_cleaner_task(); 3515 } 3516 3517 // initialize compiler(s) 3518 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3519 CompileBroker::compilation_init(); 3520 #endif 3521 3522 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3523 // It is done after compilers are initialized, because otherwise compilations of 3524 // signature polymorphic MH intrinsics can be missed 3525 // (see SystemDictionary::find_method_handle_intrinsic). 3526 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3527 3528 #if INCLUDE_MANAGEMENT 3529 Management::initialize(THREAD); 3530 3531 if (HAS_PENDING_EXCEPTION) { 3532 // management agent fails to start possibly due to 3533 // configuration problem and is responsible for printing 3534 // stack trace if appropriate. Simply exit VM. 3535 vm_exit(1); 3536 } 3537 #endif // INCLUDE_MANAGEMENT 3538 3539 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3540 if (MemProfiling) MemProfiler::engage(); 3541 StatSampler::engage(); 3542 if (CheckJNICalls) JniPeriodicChecker::engage(); 3543 3544 BiasedLocking::init(); 3545 3546 #if INCLUDE_RTM_OPT 3547 RTMLockingCounters::init(); 3548 #endif 3549 3550 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3551 call_postVMInitHook(THREAD); 3552 // The Java side of PostVMInitHook.run must deal with all 3553 // exceptions and provide means of diagnosis. 3554 if (HAS_PENDING_EXCEPTION) { 3555 CLEAR_PENDING_EXCEPTION; 3556 } 3557 } 3558 3559 { 3560 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3561 // Make sure the watcher thread can be started by WatcherThread::start() 3562 // or by dynamic enrollment. 3563 WatcherThread::make_startable(); 3564 // Start up the WatcherThread if there are any periodic tasks 3565 // NOTE: All PeriodicTasks should be registered by now. If they 3566 // aren't, late joiners might appear to start slowly (we might 3567 // take a while to process their first tick). 3568 if (PeriodicTask::num_tasks() > 0) { 3569 WatcherThread::start(); 3570 } 3571 } 3572 3573 create_vm_timer.end(); 3574 #ifdef ASSERT 3575 _vm_complete = true; 3576 #endif 3577 return JNI_OK; 3578 } 3579 3580 // type for the Agent_OnLoad and JVM_OnLoad entry points 3581 extern "C" { 3582 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3583 } 3584 // Find a command line agent library and return its entry point for 3585 // -agentlib: -agentpath: -Xrun 3586 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3587 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 3588 const char *on_load_symbols[], 3589 size_t num_symbol_entries) { 3590 OnLoadEntry_t on_load_entry = NULL; 3591 void *library = NULL; 3592 3593 if (!agent->valid()) { 3594 char buffer[JVM_MAXPATHLEN]; 3595 char ebuf[1024] = ""; 3596 const char *name = agent->name(); 3597 const char *msg = "Could not find agent library "; 3598 3599 // First check to see if agent is statically linked into executable 3600 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3601 library = agent->os_lib(); 3602 } else if (agent->is_absolute_path()) { 3603 library = os::dll_load(name, ebuf, sizeof ebuf); 3604 if (library == NULL) { 3605 const char *sub_msg = " in absolute path, with error: "; 3606 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3607 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3608 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3609 // If we can't find the agent, exit. 3610 vm_exit_during_initialization(buf, NULL); 3611 FREE_C_HEAP_ARRAY(char, buf); 3612 } 3613 } else { 3614 // Try to load the agent from the standard dll directory 3615 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3616 name)) { 3617 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3618 } 3619 if (library == NULL) { // Try the local directory 3620 char ns[1] = {0}; 3621 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3622 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3623 } 3624 if (library == NULL) { 3625 const char *sub_msg = " on the library path, with error: "; 3626 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3627 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3628 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3629 // If we can't find the agent, exit. 3630 vm_exit_during_initialization(buf, NULL); 3631 FREE_C_HEAP_ARRAY(char, buf); 3632 } 3633 } 3634 } 3635 agent->set_os_lib(library); 3636 agent->set_valid(); 3637 } 3638 3639 // Find the OnLoad function. 3640 on_load_entry = 3641 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3642 false, 3643 on_load_symbols, 3644 num_symbol_entries)); 3645 return on_load_entry; 3646 } 3647 3648 // Find the JVM_OnLoad entry point 3649 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3650 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3651 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3652 } 3653 3654 // Find the Agent_OnLoad entry point 3655 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3656 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3657 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3658 } 3659 3660 // For backwards compatibility with -Xrun 3661 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3662 // treated like -agentpath: 3663 // Must be called before agent libraries are created 3664 void Threads::convert_vm_init_libraries_to_agents() { 3665 AgentLibrary* agent; 3666 AgentLibrary* next; 3667 3668 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3669 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3670 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3671 3672 // If there is an JVM_OnLoad function it will get called later, 3673 // otherwise see if there is an Agent_OnLoad 3674 if (on_load_entry == NULL) { 3675 on_load_entry = lookup_agent_on_load(agent); 3676 if (on_load_entry != NULL) { 3677 // switch it to the agent list -- so that Agent_OnLoad will be called, 3678 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3679 Arguments::convert_library_to_agent(agent); 3680 } else { 3681 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3682 } 3683 } 3684 } 3685 } 3686 3687 // Create agents for -agentlib: -agentpath: and converted -Xrun 3688 // Invokes Agent_OnLoad 3689 // Called very early -- before JavaThreads exist 3690 void Threads::create_vm_init_agents() { 3691 extern struct JavaVM_ main_vm; 3692 AgentLibrary* agent; 3693 3694 JvmtiExport::enter_onload_phase(); 3695 3696 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3697 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3698 3699 if (on_load_entry != NULL) { 3700 // Invoke the Agent_OnLoad function 3701 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3702 if (err != JNI_OK) { 3703 vm_exit_during_initialization("agent library failed to init", agent->name()); 3704 } 3705 } else { 3706 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3707 } 3708 } 3709 JvmtiExport::enter_primordial_phase(); 3710 } 3711 3712 extern "C" { 3713 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3714 } 3715 3716 void Threads::shutdown_vm_agents() { 3717 // Send any Agent_OnUnload notifications 3718 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3719 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3720 extern struct JavaVM_ main_vm; 3721 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3722 3723 // Find the Agent_OnUnload function. 3724 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3725 os::find_agent_function(agent, 3726 false, 3727 on_unload_symbols, 3728 num_symbol_entries)); 3729 3730 // Invoke the Agent_OnUnload function 3731 if (unload_entry != NULL) { 3732 JavaThread* thread = JavaThread::current(); 3733 ThreadToNativeFromVM ttn(thread); 3734 HandleMark hm(thread); 3735 (*unload_entry)(&main_vm); 3736 } 3737 } 3738 } 3739 3740 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3741 // Invokes JVM_OnLoad 3742 void Threads::create_vm_init_libraries() { 3743 extern struct JavaVM_ main_vm; 3744 AgentLibrary* agent; 3745 3746 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3747 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3748 3749 if (on_load_entry != NULL) { 3750 // Invoke the JVM_OnLoad function 3751 JavaThread* thread = JavaThread::current(); 3752 ThreadToNativeFromVM ttn(thread); 3753 HandleMark hm(thread); 3754 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3755 if (err != JNI_OK) { 3756 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3757 } 3758 } else { 3759 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3760 } 3761 } 3762 } 3763 3764 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3765 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3766 3767 JavaThread* java_thread = NULL; 3768 // Sequential search for now. Need to do better optimization later. 3769 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3770 oop tobj = thread->threadObj(); 3771 if (!thread->is_exiting() && 3772 tobj != NULL && 3773 java_tid == java_lang_Thread::thread_id(tobj)) { 3774 java_thread = thread; 3775 break; 3776 } 3777 } 3778 return java_thread; 3779 } 3780 3781 3782 // Last thread running calls java.lang.Shutdown.shutdown() 3783 void JavaThread::invoke_shutdown_hooks() { 3784 HandleMark hm(this); 3785 3786 // We could get here with a pending exception, if so clear it now. 3787 if (this->has_pending_exception()) { 3788 this->clear_pending_exception(); 3789 } 3790 3791 EXCEPTION_MARK; 3792 Klass* k = 3793 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3794 THREAD); 3795 if (k != NULL) { 3796 // SystemDictionary::resolve_or_null will return null if there was 3797 // an exception. If we cannot load the Shutdown class, just don't 3798 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3799 // and finalizers (if runFinalizersOnExit is set) won't be run. 3800 // Note that if a shutdown hook was registered or runFinalizersOnExit 3801 // was called, the Shutdown class would have already been loaded 3802 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3803 instanceKlassHandle shutdown_klass (THREAD, k); 3804 JavaValue result(T_VOID); 3805 JavaCalls::call_static(&result, 3806 shutdown_klass, 3807 vmSymbols::shutdown_method_name(), 3808 vmSymbols::void_method_signature(), 3809 THREAD); 3810 } 3811 CLEAR_PENDING_EXCEPTION; 3812 } 3813 3814 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3815 // the program falls off the end of main(). Another VM exit path is through 3816 // vm_exit() when the program calls System.exit() to return a value or when 3817 // there is a serious error in VM. The two shutdown paths are not exactly 3818 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3819 // and VM_Exit op at VM level. 3820 // 3821 // Shutdown sequence: 3822 // + Shutdown native memory tracking if it is on 3823 // + Wait until we are the last non-daemon thread to execute 3824 // <-- every thing is still working at this moment --> 3825 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3826 // shutdown hooks, run finalizers if finalization-on-exit 3827 // + Call before_exit(), prepare for VM exit 3828 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3829 // currently the only user of this mechanism is File.deleteOnExit()) 3830 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3831 // post thread end and vm death events to JVMTI, 3832 // stop signal thread 3833 // + Call JavaThread::exit(), it will: 3834 // > release JNI handle blocks, remove stack guard pages 3835 // > remove this thread from Threads list 3836 // <-- no more Java code from this thread after this point --> 3837 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3838 // the compiler threads at safepoint 3839 // <-- do not use anything that could get blocked by Safepoint --> 3840 // + Disable tracing at JNI/JVM barriers 3841 // + Set _vm_exited flag for threads that are still running native code 3842 // + Delete this thread 3843 // + Call exit_globals() 3844 // > deletes tty 3845 // > deletes PerfMemory resources 3846 // + Return to caller 3847 3848 bool Threads::destroy_vm() { 3849 JavaThread* thread = JavaThread::current(); 3850 3851 #ifdef ASSERT 3852 _vm_complete = false; 3853 #endif 3854 // Wait until we are the last non-daemon thread to execute 3855 { MutexLocker nu(Threads_lock); 3856 while (Threads::number_of_non_daemon_threads() > 1) 3857 // This wait should make safepoint checks, wait without a timeout, 3858 // and wait as a suspend-equivalent condition. 3859 // 3860 // Note: If the FlatProfiler is running and this thread is waiting 3861 // for another non-daemon thread to finish, then the FlatProfiler 3862 // is waiting for the external suspend request on this thread to 3863 // complete. wait_for_ext_suspend_completion() will eventually 3864 // timeout, but that takes time. Making this wait a suspend- 3865 // equivalent condition solves that timeout problem. 3866 // 3867 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3868 Mutex::_as_suspend_equivalent_flag); 3869 } 3870 3871 // Hang forever on exit if we are reporting an error. 3872 if (ShowMessageBoxOnError && is_error_reported()) { 3873 os::infinite_sleep(); 3874 } 3875 os::wait_for_keypress_at_exit(); 3876 3877 // run Java level shutdown hooks 3878 thread->invoke_shutdown_hooks(); 3879 3880 before_exit(thread); 3881 3882 thread->exit(true); 3883 3884 // Stop VM thread. 3885 { 3886 // 4945125 The vm thread comes to a safepoint during exit. 3887 // GC vm_operations can get caught at the safepoint, and the 3888 // heap is unparseable if they are caught. Grab the Heap_lock 3889 // to prevent this. The GC vm_operations will not be able to 3890 // queue until after the vm thread is dead. After this point, 3891 // we'll never emerge out of the safepoint before the VM exits. 3892 3893 MutexLocker ml(Heap_lock); 3894 3895 VMThread::wait_for_vm_thread_exit(); 3896 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3897 VMThread::destroy(); 3898 } 3899 3900 // clean up ideal graph printers 3901 #if defined(COMPILER2) && !defined(PRODUCT) 3902 IdealGraphPrinter::clean_up(); 3903 #endif 3904 3905 // Now, all Java threads are gone except daemon threads. Daemon threads 3906 // running Java code or in VM are stopped by the Safepoint. However, 3907 // daemon threads executing native code are still running. But they 3908 // will be stopped at native=>Java/VM barriers. Note that we can't 3909 // simply kill or suspend them, as it is inherently deadlock-prone. 3910 3911 #ifndef PRODUCT 3912 // disable function tracing at JNI/JVM barriers 3913 TraceJNICalls = false; 3914 TraceJVMCalls = false; 3915 TraceRuntimeCalls = false; 3916 #endif 3917 3918 VM_Exit::set_vm_exited(); 3919 3920 notify_vm_shutdown(); 3921 3922 delete thread; 3923 3924 // exit_globals() will delete tty 3925 exit_globals(); 3926 3927 return true; 3928 } 3929 3930 3931 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 3932 if (version == JNI_VERSION_1_1) return JNI_TRUE; 3933 return is_supported_jni_version(version); 3934 } 3935 3936 3937 jboolean Threads::is_supported_jni_version(jint version) { 3938 if (version == JNI_VERSION_1_2) return JNI_TRUE; 3939 if (version == JNI_VERSION_1_4) return JNI_TRUE; 3940 if (version == JNI_VERSION_1_6) return JNI_TRUE; 3941 if (version == JNI_VERSION_1_8) return JNI_TRUE; 3942 return JNI_FALSE; 3943 } 3944 3945 3946 void Threads::add(JavaThread* p, bool force_daemon) { 3947 // The threads lock must be owned at this point 3948 assert_locked_or_safepoint(Threads_lock); 3949 3950 // See the comment for this method in thread.hpp for its purpose and 3951 // why it is called here. 3952 p->initialize_queues(); 3953 p->set_next(_thread_list); 3954 _thread_list = p; 3955 _number_of_threads++; 3956 oop threadObj = p->threadObj(); 3957 bool daemon = true; 3958 // Bootstrapping problem: threadObj can be null for initial 3959 // JavaThread (or for threads attached via JNI) 3960 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 3961 _number_of_non_daemon_threads++; 3962 daemon = false; 3963 } 3964 3965 ThreadService::add_thread(p, daemon); 3966 3967 // Possible GC point. 3968 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 3969 } 3970 3971 void Threads::remove(JavaThread* p) { 3972 // Extra scope needed for Thread_lock, so we can check 3973 // that we do not remove thread without safepoint code notice 3974 { MutexLocker ml(Threads_lock); 3975 3976 assert(includes(p), "p must be present"); 3977 3978 JavaThread* current = _thread_list; 3979 JavaThread* prev = NULL; 3980 3981 while (current != p) { 3982 prev = current; 3983 current = current->next(); 3984 } 3985 3986 if (prev) { 3987 prev->set_next(current->next()); 3988 } else { 3989 _thread_list = p->next(); 3990 } 3991 _number_of_threads--; 3992 oop threadObj = p->threadObj(); 3993 bool daemon = true; 3994 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 3995 _number_of_non_daemon_threads--; 3996 daemon = false; 3997 3998 // Only one thread left, do a notify on the Threads_lock so a thread waiting 3999 // on destroy_vm will wake up. 4000 if (number_of_non_daemon_threads() == 1) { 4001 Threads_lock->notify_all(); 4002 } 4003 } 4004 ThreadService::remove_thread(p, daemon); 4005 4006 // Make sure that safepoint code disregard this thread. This is needed since 4007 // the thread might mess around with locks after this point. This can cause it 4008 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4009 // of this thread since it is removed from the queue. 4010 p->set_terminated_value(); 4011 } // unlock Threads_lock 4012 4013 // Since Events::log uses a lock, we grab it outside the Threads_lock 4014 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4015 } 4016 4017 // Threads_lock must be held when this is called (or must be called during a safepoint) 4018 bool Threads::includes(JavaThread* p) { 4019 assert(Threads_lock->is_locked(), "sanity check"); 4020 ALL_JAVA_THREADS(q) { 4021 if (q == p) { 4022 return true; 4023 } 4024 } 4025 return false; 4026 } 4027 4028 // Operations on the Threads list for GC. These are not explicitly locked, 4029 // but the garbage collector must provide a safe context for them to run. 4030 // In particular, these things should never be called when the Threads_lock 4031 // is held by some other thread. (Note: the Safepoint abstraction also 4032 // uses the Threads_lock to guarantee this property. It also makes sure that 4033 // all threads gets blocked when exiting or starting). 4034 4035 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4036 ALL_JAVA_THREADS(p) { 4037 p->oops_do(f, cld_f, cf); 4038 } 4039 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4040 } 4041 4042 void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4043 // Introduce a mechanism allowing parallel threads to claim threads as 4044 // root groups. Overhead should be small enough to use all the time, 4045 // even in sequential code. 4046 SharedHeap* sh = SharedHeap::heap(); 4047 // Cannot yet substitute active_workers for n_par_threads 4048 // because of G1CollectedHeap::verify() use of 4049 // SharedHeap::process_roots(). n_par_threads == 0 will 4050 // turn off parallelism in process_roots while active_workers 4051 // is being used for parallelism elsewhere. 4052 bool is_par = sh->n_par_threads() > 0; 4053 assert(!is_par || 4054 (SharedHeap::heap()->n_par_threads() == 4055 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4056 int cp = SharedHeap::heap()->strong_roots_parity(); 4057 ALL_JAVA_THREADS(p) { 4058 if (p->claim_oops_do(is_par, cp)) { 4059 p->oops_do(f, cld_f, cf); 4060 } 4061 } 4062 VMThread* vmt = VMThread::vm_thread(); 4063 if (vmt->claim_oops_do(is_par, cp)) { 4064 vmt->oops_do(f, cld_f, cf); 4065 } 4066 } 4067 4068 #if INCLUDE_ALL_GCS 4069 // Used by ParallelScavenge 4070 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4071 ALL_JAVA_THREADS(p) { 4072 q->enqueue(new ThreadRootsTask(p)); 4073 } 4074 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4075 } 4076 4077 // Used by Parallel Old 4078 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4079 ALL_JAVA_THREADS(p) { 4080 q->enqueue(new ThreadRootsMarkingTask(p)); 4081 } 4082 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4083 } 4084 #endif // INCLUDE_ALL_GCS 4085 4086 void Threads::nmethods_do(CodeBlobClosure* cf) { 4087 ALL_JAVA_THREADS(p) { 4088 p->nmethods_do(cf); 4089 } 4090 VMThread::vm_thread()->nmethods_do(cf); 4091 } 4092 4093 void Threads::metadata_do(void f(Metadata*)) { 4094 ALL_JAVA_THREADS(p) { 4095 p->metadata_do(f); 4096 } 4097 } 4098 4099 void Threads::deoptimized_wrt_marked_nmethods() { 4100 ALL_JAVA_THREADS(p) { 4101 p->deoptimized_wrt_marked_nmethods(); 4102 } 4103 } 4104 4105 4106 // Get count Java threads that are waiting to enter the specified monitor. 4107 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4108 address monitor, 4109 bool doLock) { 4110 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4111 "must grab Threads_lock or be at safepoint"); 4112 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4113 4114 int i = 0; 4115 { 4116 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4117 ALL_JAVA_THREADS(p) { 4118 if (p->is_Compiler_thread()) continue; 4119 4120 address pending = (address)p->current_pending_monitor(); 4121 if (pending == monitor) { // found a match 4122 if (i < count) result->append(p); // save the first count matches 4123 i++; 4124 } 4125 } 4126 } 4127 return result; 4128 } 4129 4130 4131 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, 4132 bool doLock) { 4133 assert(doLock || 4134 Threads_lock->owned_by_self() || 4135 SafepointSynchronize::is_at_safepoint(), 4136 "must grab Threads_lock or be at safepoint"); 4137 4138 // NULL owner means not locked so we can skip the search 4139 if (owner == NULL) return NULL; 4140 4141 { 4142 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4143 ALL_JAVA_THREADS(p) { 4144 // first, see if owner is the address of a Java thread 4145 if (owner == (address)p) return p; 4146 } 4147 } 4148 // Cannot assert on lack of success here since this function may be 4149 // used by code that is trying to report useful problem information 4150 // like deadlock detection. 4151 if (UseHeavyMonitors) return NULL; 4152 4153 // If we didn't find a matching Java thread and we didn't force use of 4154 // heavyweight monitors, then the owner is the stack address of the 4155 // Lock Word in the owning Java thread's stack. 4156 // 4157 JavaThread* the_owner = NULL; 4158 { 4159 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4160 ALL_JAVA_THREADS(q) { 4161 if (q->is_lock_owned(owner)) { 4162 the_owner = q; 4163 break; 4164 } 4165 } 4166 } 4167 // cannot assert on lack of success here; see above comment 4168 return the_owner; 4169 } 4170 4171 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4172 void Threads::print_on(outputStream* st, bool print_stacks, 4173 bool internal_format, bool print_concurrent_locks) { 4174 char buf[32]; 4175 st->print_cr("%s", os::local_time_string(buf, sizeof(buf))); 4176 4177 st->print_cr("Full thread dump %s (%s %s):", 4178 Abstract_VM_Version::vm_name(), 4179 Abstract_VM_Version::vm_release(), 4180 Abstract_VM_Version::vm_info_string()); 4181 st->cr(); 4182 4183 #if INCLUDE_ALL_GCS 4184 // Dump concurrent locks 4185 ConcurrentLocksDump concurrent_locks; 4186 if (print_concurrent_locks) { 4187 concurrent_locks.dump_at_safepoint(); 4188 } 4189 #endif // INCLUDE_ALL_GCS 4190 4191 ALL_JAVA_THREADS(p) { 4192 ResourceMark rm; 4193 p->print_on(st); 4194 if (print_stacks) { 4195 if (internal_format) { 4196 p->trace_stack(); 4197 } else { 4198 p->print_stack_on(st); 4199 } 4200 } 4201 st->cr(); 4202 #if INCLUDE_ALL_GCS 4203 if (print_concurrent_locks) { 4204 concurrent_locks.print_locks_on(p, st); 4205 } 4206 #endif // INCLUDE_ALL_GCS 4207 } 4208 4209 VMThread::vm_thread()->print_on(st); 4210 st->cr(); 4211 Universe::heap()->print_gc_threads_on(st); 4212 WatcherThread* wt = WatcherThread::watcher_thread(); 4213 if (wt != NULL) { 4214 wt->print_on(st); 4215 st->cr(); 4216 } 4217 CompileBroker::print_compiler_threads_on(st); 4218 st->flush(); 4219 } 4220 4221 // Threads::print_on_error() is called by fatal error handler. It's possible 4222 // that VM is not at safepoint and/or current thread is inside signal handler. 4223 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4224 // memory (even in resource area), it might deadlock the error handler. 4225 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4226 int buflen) { 4227 bool found_current = false; 4228 st->print_cr("Java Threads: ( => current thread )"); 4229 ALL_JAVA_THREADS(thread) { 4230 bool is_current = (current == thread); 4231 found_current = found_current || is_current; 4232 4233 st->print("%s", is_current ? "=>" : " "); 4234 4235 st->print(PTR_FORMAT, thread); 4236 st->print(" "); 4237 thread->print_on_error(st, buf, buflen); 4238 st->cr(); 4239 } 4240 st->cr(); 4241 4242 st->print_cr("Other Threads:"); 4243 if (VMThread::vm_thread()) { 4244 bool is_current = (current == VMThread::vm_thread()); 4245 found_current = found_current || is_current; 4246 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4247 4248 st->print(PTR_FORMAT, VMThread::vm_thread()); 4249 st->print(" "); 4250 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4251 st->cr(); 4252 } 4253 WatcherThread* wt = WatcherThread::watcher_thread(); 4254 if (wt != NULL) { 4255 bool is_current = (current == wt); 4256 found_current = found_current || is_current; 4257 st->print("%s", is_current ? "=>" : " "); 4258 4259 st->print(PTR_FORMAT, wt); 4260 st->print(" "); 4261 wt->print_on_error(st, buf, buflen); 4262 st->cr(); 4263 } 4264 if (!found_current) { 4265 st->cr(); 4266 st->print("=>" PTR_FORMAT " (exited) ", current); 4267 current->print_on_error(st, buf, buflen); 4268 st->cr(); 4269 } 4270 } 4271 4272 // Internal SpinLock and Mutex 4273 // Based on ParkEvent 4274 4275 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4276 // 4277 // We employ SpinLocks _only for low-contention, fixed-length 4278 // short-duration critical sections where we're concerned 4279 // about native mutex_t or HotSpot Mutex:: latency. 4280 // The mux construct provides a spin-then-block mutual exclusion 4281 // mechanism. 4282 // 4283 // Testing has shown that contention on the ListLock guarding gFreeList 4284 // is common. If we implement ListLock as a simple SpinLock it's common 4285 // for the JVM to devolve to yielding with little progress. This is true 4286 // despite the fact that the critical sections protected by ListLock are 4287 // extremely short. 4288 // 4289 // TODO-FIXME: ListLock should be of type SpinLock. 4290 // We should make this a 1st-class type, integrated into the lock 4291 // hierarchy as leaf-locks. Critically, the SpinLock structure 4292 // should have sufficient padding to avoid false-sharing and excessive 4293 // cache-coherency traffic. 4294 4295 4296 typedef volatile int SpinLockT; 4297 4298 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4299 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4300 return; // normal fast-path return 4301 } 4302 4303 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4304 TEVENT(SpinAcquire - ctx); 4305 int ctr = 0; 4306 int Yields = 0; 4307 for (;;) { 4308 while (*adr != 0) { 4309 ++ctr; 4310 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4311 if (Yields > 5) { 4312 os::naked_short_sleep(1); 4313 } else { 4314 os::naked_yield(); 4315 ++Yields; 4316 } 4317 } else { 4318 SpinPause(); 4319 } 4320 } 4321 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4322 } 4323 } 4324 4325 void Thread::SpinRelease(volatile int * adr) { 4326 assert(*adr != 0, "invariant"); 4327 OrderAccess::fence(); // guarantee at least release consistency. 4328 // Roach-motel semantics. 4329 // It's safe if subsequent LDs and STs float "up" into the critical section, 4330 // but prior LDs and STs within the critical section can't be allowed 4331 // to reorder or float past the ST that releases the lock. 4332 // Loads and stores in the critical section - which appear in program 4333 // order before the store that releases the lock - must also appear 4334 // before the store that releases the lock in memory visibility order. 4335 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4336 // the ST of 0 into the lock-word which releases the lock, so fence 4337 // more than covers this on all platforms. 4338 *adr = 0; 4339 } 4340 4341 // muxAcquire and muxRelease: 4342 // 4343 // * muxAcquire and muxRelease support a single-word lock-word construct. 4344 // The LSB of the word is set IFF the lock is held. 4345 // The remainder of the word points to the head of a singly-linked list 4346 // of threads blocked on the lock. 4347 // 4348 // * The current implementation of muxAcquire-muxRelease uses its own 4349 // dedicated Thread._MuxEvent instance. If we're interested in 4350 // minimizing the peak number of extant ParkEvent instances then 4351 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4352 // as certain invariants were satisfied. Specifically, care would need 4353 // to be taken with regards to consuming unpark() "permits". 4354 // A safe rule of thumb is that a thread would never call muxAcquire() 4355 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4356 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4357 // consume an unpark() permit intended for monitorenter, for instance. 4358 // One way around this would be to widen the restricted-range semaphore 4359 // implemented in park(). Another alternative would be to provide 4360 // multiple instances of the PlatformEvent() for each thread. One 4361 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4362 // 4363 // * Usage: 4364 // -- Only as leaf locks 4365 // -- for short-term locking only as muxAcquire does not perform 4366 // thread state transitions. 4367 // 4368 // Alternatives: 4369 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4370 // but with parking or spin-then-park instead of pure spinning. 4371 // * Use Taura-Oyama-Yonenzawa locks. 4372 // * It's possible to construct a 1-0 lock if we encode the lockword as 4373 // (List,LockByte). Acquire will CAS the full lockword while Release 4374 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4375 // acquiring threads use timers (ParkTimed) to detect and recover from 4376 // the stranding window. Thread/Node structures must be aligned on 256-byte 4377 // boundaries by using placement-new. 4378 // * Augment MCS with advisory back-link fields maintained with CAS(). 4379 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4380 // The validity of the backlinks must be ratified before we trust the value. 4381 // If the backlinks are invalid the exiting thread must back-track through the 4382 // the forward links, which are always trustworthy. 4383 // * Add a successor indication. The LockWord is currently encoded as 4384 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4385 // to provide the usual futile-wakeup optimization. 4386 // See RTStt for details. 4387 // * Consider schedctl.sc_nopreempt to cover the critical section. 4388 // 4389 4390 4391 typedef volatile intptr_t MutexT; // Mux Lock-word 4392 enum MuxBits { LOCKBIT = 1 }; 4393 4394 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4395 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4396 if (w == 0) return; 4397 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4398 return; 4399 } 4400 4401 TEVENT(muxAcquire - Contention); 4402 ParkEvent * const Self = Thread::current()->_MuxEvent; 4403 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4404 for (;;) { 4405 int its = (os::is_MP() ? 100 : 0) + 1; 4406 4407 // Optional spin phase: spin-then-park strategy 4408 while (--its >= 0) { 4409 w = *Lock; 4410 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4411 return; 4412 } 4413 } 4414 4415 Self->reset(); 4416 Self->OnList = intptr_t(Lock); 4417 // The following fence() isn't _strictly necessary as the subsequent 4418 // CAS() both serializes execution and ratifies the fetched *Lock value. 4419 OrderAccess::fence(); 4420 for (;;) { 4421 w = *Lock; 4422 if ((w & LOCKBIT) == 0) { 4423 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4424 Self->OnList = 0; // hygiene - allows stronger asserts 4425 return; 4426 } 4427 continue; // Interference -- *Lock changed -- Just retry 4428 } 4429 assert(w & LOCKBIT, "invariant"); 4430 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4431 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4432 } 4433 4434 while (Self->OnList != 0) { 4435 Self->park(); 4436 } 4437 } 4438 } 4439 4440 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4441 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4442 if (w == 0) return; 4443 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4444 return; 4445 } 4446 4447 TEVENT(muxAcquire - Contention); 4448 ParkEvent * ReleaseAfter = NULL; 4449 if (ev == NULL) { 4450 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4451 } 4452 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4453 for (;;) { 4454 guarantee(ev->OnList == 0, "invariant"); 4455 int its = (os::is_MP() ? 100 : 0) + 1; 4456 4457 // Optional spin phase: spin-then-park strategy 4458 while (--its >= 0) { 4459 w = *Lock; 4460 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4461 if (ReleaseAfter != NULL) { 4462 ParkEvent::Release(ReleaseAfter); 4463 } 4464 return; 4465 } 4466 } 4467 4468 ev->reset(); 4469 ev->OnList = intptr_t(Lock); 4470 // The following fence() isn't _strictly necessary as the subsequent 4471 // CAS() both serializes execution and ratifies the fetched *Lock value. 4472 OrderAccess::fence(); 4473 for (;;) { 4474 w = *Lock; 4475 if ((w & LOCKBIT) == 0) { 4476 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4477 ev->OnList = 0; 4478 // We call ::Release while holding the outer lock, thus 4479 // artificially lengthening the critical section. 4480 // Consider deferring the ::Release() until the subsequent unlock(), 4481 // after we've dropped the outer lock. 4482 if (ReleaseAfter != NULL) { 4483 ParkEvent::Release(ReleaseAfter); 4484 } 4485 return; 4486 } 4487 continue; // Interference -- *Lock changed -- Just retry 4488 } 4489 assert(w & LOCKBIT, "invariant"); 4490 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4491 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4492 } 4493 4494 while (ev->OnList != 0) { 4495 ev->park(); 4496 } 4497 } 4498 } 4499 4500 // Release() must extract a successor from the list and then wake that thread. 4501 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4502 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4503 // Release() would : 4504 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4505 // (B) Extract a successor from the private list "in-hand" 4506 // (C) attempt to CAS() the residual back into *Lock over null. 4507 // If there were any newly arrived threads and the CAS() would fail. 4508 // In that case Release() would detach the RATs, re-merge the list in-hand 4509 // with the RATs and repeat as needed. Alternately, Release() might 4510 // detach and extract a successor, but then pass the residual list to the wakee. 4511 // The wakee would be responsible for reattaching and remerging before it 4512 // competed for the lock. 4513 // 4514 // Both "pop" and DMR are immune from ABA corruption -- there can be 4515 // multiple concurrent pushers, but only one popper or detacher. 4516 // This implementation pops from the head of the list. This is unfair, 4517 // but tends to provide excellent throughput as hot threads remain hot. 4518 // (We wake recently run threads first). 4519 // 4520 // All paths through muxRelease() will execute a CAS. 4521 // Release consistency -- We depend on the CAS in muxRelease() to provide full 4522 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4523 // executed within the critical section are complete and globally visible before the 4524 // store (CAS) to the lock-word that releases the lock becomes globally visible. 4525 void Thread::muxRelease(volatile intptr_t * Lock) { 4526 for (;;) { 4527 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4528 assert(w & LOCKBIT, "invariant"); 4529 if (w == LOCKBIT) return; 4530 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4531 assert(List != NULL, "invariant"); 4532 assert(List->OnList == intptr_t(Lock), "invariant"); 4533 ParkEvent * const nxt = List->ListNext; 4534 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4535 4536 // The following CAS() releases the lock and pops the head element. 4537 // The CAS() also ratifies the previously fetched lock-word value. 4538 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4539 continue; 4540 } 4541 List->OnList = 0; 4542 OrderAccess::fence(); 4543 List->unpark(); 4544 return; 4545 } 4546 } 4547 4548 4549 void Threads::verify() { 4550 ALL_JAVA_THREADS(p) { 4551 p->verify(); 4552 } 4553 VMThread* thread = VMThread::vm_thread(); 4554 if (thread != NULL) thread->verify(); 4555 }