1 /* 2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/classLoader.hpp" 27 #include "classfile/javaClasses.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "code/codeCache.hpp" 31 #include "code/codeCacheExtensions.hpp" 32 #include "code/scopeDesc.hpp" 33 #include "compiler/compileBroker.hpp" 34 #include "gc/shared/gcId.hpp" 35 #include "gc/shared/gcLocker.inline.hpp" 36 #include "gc/shared/workgroup.hpp" 37 #include "interpreter/interpreter.hpp" 38 #include "interpreter/linkResolver.hpp" 39 #include "interpreter/oopMapCache.hpp" 40 #include "jvmtifiles/jvmtiEnv.hpp" 41 #include "logging/logConfiguration.hpp" 42 #include "memory/metaspaceShared.hpp" 43 #include "memory/oopFactory.hpp" 44 #include "memory/universe.inline.hpp" 45 #include "oops/instanceKlass.hpp" 46 #include "oops/objArrayOop.hpp" 47 #include "oops/oop.inline.hpp" 48 #include "oops/symbol.hpp" 49 #include "oops/verifyOopClosure.hpp" 50 #include "prims/jvm_misc.hpp" 51 #include "prims/jvmtiExport.hpp" 52 #include "prims/jvmtiThreadState.hpp" 53 #include "prims/privilegedStack.hpp" 54 #include "runtime/arguments.hpp" 55 #include "runtime/atomic.inline.hpp" 56 #include "runtime/biasedLocking.hpp" 57 #include "runtime/commandLineFlagConstraintList.hpp" 58 #include "runtime/commandLineFlagRangeList.hpp" 59 #include "runtime/deoptimization.hpp" 60 #include "runtime/fprofiler.hpp" 61 #include "runtime/frame.inline.hpp" 62 #include "runtime/globals.hpp" 63 #include "runtime/init.hpp" 64 #include "runtime/interfaceSupport.hpp" 65 #include "runtime/java.hpp" 66 #include "runtime/javaCalls.hpp" 67 #include "runtime/jniPeriodicChecker.hpp" 68 #include "runtime/memprofiler.hpp" 69 #include "runtime/mutexLocker.hpp" 70 #include "runtime/objectMonitor.hpp" 71 #include "runtime/orderAccess.inline.hpp" 72 #include "runtime/osThread.hpp" 73 #include "runtime/safepoint.hpp" 74 #include "runtime/sharedRuntime.hpp" 75 #include "runtime/statSampler.hpp" 76 #include "runtime/stubRoutines.hpp" 77 #include "runtime/sweeper.hpp" 78 #include "runtime/task.hpp" 79 #include "runtime/thread.inline.hpp" 80 #include "runtime/threadCritical.hpp" 81 #include "runtime/threadLocalStorage.hpp" 82 #include "runtime/vframe.hpp" 83 #include "runtime/vframeArray.hpp" 84 #include "runtime/vframe_hp.hpp" 85 #include "runtime/vmThread.hpp" 86 #include "runtime/vm_operations.hpp" 87 #include "runtime/vm_version.hpp" 88 #include "services/attachListener.hpp" 89 #include "services/management.hpp" 90 #include "services/memTracker.hpp" 91 #include "services/threadService.hpp" 92 #include "trace/traceMacros.hpp" 93 #include "trace/tracing.hpp" 94 #include "utilities/defaultStream.hpp" 95 #include "utilities/dtrace.hpp" 96 #include "utilities/events.hpp" 97 #include "utilities/macros.hpp" 98 #include "utilities/preserveException.hpp" 99 #if INCLUDE_ALL_GCS 100 #include "gc/cms/concurrentMarkSweepThread.hpp" 101 #include "gc/g1/concurrentMarkThread.inline.hpp" 102 #include "gc/parallel/pcTasks.hpp" 103 #endif // INCLUDE_ALL_GCS 104 #if INCLUDE_JVMCI 105 #include "jvmci/jvmciCompiler.hpp" 106 #include "jvmci/jvmciRuntime.hpp" 107 #endif 108 #ifdef COMPILER1 109 #include "c1/c1_Compiler.hpp" 110 #endif 111 #ifdef COMPILER2 112 #include "opto/c2compiler.hpp" 113 #include "opto/idealGraphPrinter.hpp" 114 #endif 115 #if INCLUDE_RTM_OPT 116 #include "runtime/rtmLocking.hpp" 117 #endif 118 119 #ifdef DTRACE_ENABLED 120 121 // Only bother with this argument setup if dtrace is available 122 123 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 124 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 125 126 #define DTRACE_THREAD_PROBE(probe, javathread) \ 127 { \ 128 ResourceMark rm(this); \ 129 int len = 0; \ 130 const char* name = (javathread)->get_thread_name(); \ 131 len = strlen(name); \ 132 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 133 (char *) name, len, \ 134 java_lang_Thread::thread_id((javathread)->threadObj()), \ 135 (uintptr_t) (javathread)->osthread()->thread_id(), \ 136 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 137 } 138 139 #else // ndef DTRACE_ENABLED 140 141 #define DTRACE_THREAD_PROBE(probe, javathread) 142 143 #endif // ndef DTRACE_ENABLED 144 145 146 // Class hierarchy 147 // - Thread 148 // - VMThread 149 // - WatcherThread 150 // - ConcurrentMarkSweepThread 151 // - JavaThread 152 // - CompilerThread 153 154 // ======= Thread ======== 155 // Support for forcing alignment of thread objects for biased locking 156 void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 157 if (UseBiasedLocking) { 158 const int alignment = markOopDesc::biased_lock_alignment; 159 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 160 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 161 : AllocateHeap(aligned_size, flags, CURRENT_PC, 162 AllocFailStrategy::RETURN_NULL); 163 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 164 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 165 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 166 "JavaThread alignment code overflowed allocated storage"); 167 if (TraceBiasedLocking) { 168 if (aligned_addr != real_malloc_addr) { 169 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 170 p2i(real_malloc_addr), p2i(aligned_addr)); 171 } 172 } 173 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 174 return aligned_addr; 175 } else { 176 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 177 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 178 } 179 } 180 181 void Thread::operator delete(void* p) { 182 if (UseBiasedLocking) { 183 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 184 FreeHeap(real_malloc_addr); 185 } else { 186 FreeHeap(p); 187 } 188 } 189 190 191 // Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 192 // JavaThread 193 194 195 Thread::Thread() { 196 // stack and get_thread 197 set_stack_base(NULL); 198 set_stack_size(0); 199 set_self_raw_id(0); 200 set_lgrp_id(-1); 201 DEBUG_ONLY(clear_suspendible_thread();) 202 203 // allocated data structures 204 set_osthread(NULL); 205 set_resource_area(new (mtThread)ResourceArea()); 206 DEBUG_ONLY(_current_resource_mark = NULL;) 207 set_handle_area(new (mtThread) HandleArea(NULL)); 208 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 209 set_active_handles(NULL); 210 set_free_handle_block(NULL); 211 set_last_handle_mark(NULL); 212 213 // This initial value ==> never claimed. 214 _oops_do_parity = 0; 215 216 // the handle mark links itself to last_handle_mark 217 new HandleMark(this); 218 219 // plain initialization 220 debug_only(_owned_locks = NULL;) 221 debug_only(_allow_allocation_count = 0;) 222 NOT_PRODUCT(_allow_safepoint_count = 0;) 223 NOT_PRODUCT(_skip_gcalot = false;) 224 _jvmti_env_iteration_count = 0; 225 set_allocated_bytes(0); 226 _vm_operation_started_count = 0; 227 _vm_operation_completed_count = 0; 228 _current_pending_monitor = NULL; 229 _current_pending_monitor_is_from_java = true; 230 _current_waiting_monitor = NULL; 231 _num_nested_signal = 0; 232 omFreeList = NULL; 233 omFreeCount = 0; 234 omFreeProvision = 32; 235 omInUseList = NULL; 236 omInUseCount = 0; 237 238 #ifdef ASSERT 239 _visited_for_critical_count = false; 240 #endif 241 242 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, 243 Monitor::_safepoint_check_sometimes); 244 _suspend_flags = 0; 245 246 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 247 _hashStateX = os::random(); 248 _hashStateY = 842502087; 249 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 250 _hashStateW = 273326509; 251 252 _OnTrap = 0; 253 _schedctl = NULL; 254 _Stalled = 0; 255 _TypeTag = 0x2BAD; 256 257 // Many of the following fields are effectively final - immutable 258 // Note that nascent threads can't use the Native Monitor-Mutex 259 // construct until the _MutexEvent is initialized ... 260 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 261 // we might instead use a stack of ParkEvents that we could provision on-demand. 262 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 263 // and ::Release() 264 _ParkEvent = ParkEvent::Allocate(this); 265 _SleepEvent = ParkEvent::Allocate(this); 266 _MutexEvent = ParkEvent::Allocate(this); 267 _MuxEvent = ParkEvent::Allocate(this); 268 269 #ifdef CHECK_UNHANDLED_OOPS 270 if (CheckUnhandledOops) { 271 _unhandled_oops = new UnhandledOops(this); 272 } 273 #endif // CHECK_UNHANDLED_OOPS 274 #ifdef ASSERT 275 if (UseBiasedLocking) { 276 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 277 assert(this == _real_malloc_address || 278 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 279 "bug in forced alignment of thread objects"); 280 } 281 #endif // ASSERT 282 } 283 284 // Non-inlined version to be used where thread.inline.hpp shouldn't be included. 285 Thread* Thread::current_noinline() { 286 return Thread::current(); 287 } 288 289 void Thread::initialize_thread_local_storage() { 290 // Note: Make sure this method only calls 291 // non-blocking operations. Otherwise, it might not work 292 // with the thread-startup/safepoint interaction. 293 294 // During Java thread startup, safepoint code should allow this 295 // method to complete because it may need to allocate memory to 296 // store information for the new thread. 297 298 // initialize structure dependent on thread local storage 299 ThreadLocalStorage::set_thread(this); 300 } 301 302 void Thread::record_stack_base_and_size() { 303 set_stack_base(os::current_stack_base()); 304 set_stack_size(os::current_stack_size()); 305 if (is_Java_thread()) { 306 ((JavaThread*) this)->set_stack_overflow_limit(); 307 } 308 // CR 7190089: on Solaris, primordial thread's stack is adjusted 309 // in initialize_thread(). Without the adjustment, stack size is 310 // incorrect if stack is set to unlimited (ulimit -s unlimited). 311 // So far, only Solaris has real implementation of initialize_thread(). 312 // 313 // set up any platform-specific state. 314 os::initialize_thread(this); 315 316 #if INCLUDE_NMT 317 // record thread's native stack, stack grows downward 318 address stack_low_addr = stack_base() - stack_size(); 319 MemTracker::record_thread_stack(stack_low_addr, stack_size()); 320 #endif // INCLUDE_NMT 321 } 322 323 324 Thread::~Thread() { 325 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 326 ObjectSynchronizer::omFlush(this); 327 328 EVENT_THREAD_DESTRUCT(this); 329 330 // stack_base can be NULL if the thread is never started or exited before 331 // record_stack_base_and_size called. Although, we would like to ensure 332 // that all started threads do call record_stack_base_and_size(), there is 333 // not proper way to enforce that. 334 #if INCLUDE_NMT 335 if (_stack_base != NULL) { 336 address low_stack_addr = stack_base() - stack_size(); 337 MemTracker::release_thread_stack(low_stack_addr, stack_size()); 338 #ifdef ASSERT 339 set_stack_base(NULL); 340 #endif 341 } 342 #endif // INCLUDE_NMT 343 344 // deallocate data structures 345 delete resource_area(); 346 // since the handle marks are using the handle area, we have to deallocated the root 347 // handle mark before deallocating the thread's handle area, 348 assert(last_handle_mark() != NULL, "check we have an element"); 349 delete last_handle_mark(); 350 assert(last_handle_mark() == NULL, "check we have reached the end"); 351 352 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 353 // We NULL out the fields for good hygiene. 354 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 355 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 356 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 357 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 358 359 delete handle_area(); 360 delete metadata_handles(); 361 362 // osthread() can be NULL, if creation of thread failed. 363 if (osthread() != NULL) os::free_thread(osthread()); 364 365 delete _SR_lock; 366 367 // clear thread local storage if the Thread is deleting itself 368 if (this == Thread::current()) { 369 ThreadLocalStorage::set_thread(NULL); 370 } else { 371 // In the case where we're not the current thread, invalidate all the 372 // caches in case some code tries to get the current thread or the 373 // thread that was destroyed, and gets stale information. 374 ThreadLocalStorage::invalidate_all(); 375 } 376 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 377 } 378 379 // NOTE: dummy function for assertion purpose. 380 void Thread::run() { 381 ShouldNotReachHere(); 382 } 383 384 #ifdef ASSERT 385 // Private method to check for dangling thread pointer 386 void check_for_dangling_thread_pointer(Thread *thread) { 387 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 388 "possibility of dangling Thread pointer"); 389 } 390 #endif 391 392 ThreadPriority Thread::get_priority(const Thread* const thread) { 393 ThreadPriority priority; 394 // Can return an error! 395 (void)os::get_priority(thread, priority); 396 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 397 return priority; 398 } 399 400 void Thread::set_priority(Thread* thread, ThreadPriority priority) { 401 debug_only(check_for_dangling_thread_pointer(thread);) 402 // Can return an error! 403 (void)os::set_priority(thread, priority); 404 } 405 406 407 void Thread::start(Thread* thread) { 408 // Start is different from resume in that its safety is guaranteed by context or 409 // being called from a Java method synchronized on the Thread object. 410 if (!DisableStartThread) { 411 if (thread->is_Java_thread()) { 412 // Initialize the thread state to RUNNABLE before starting this thread. 413 // Can not set it after the thread started because we do not know the 414 // exact thread state at that time. It could be in MONITOR_WAIT or 415 // in SLEEPING or some other state. 416 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 417 java_lang_Thread::RUNNABLE); 418 } 419 os::start_thread(thread); 420 } 421 } 422 423 // Enqueue a VM_Operation to do the job for us - sometime later 424 void Thread::send_async_exception(oop java_thread, oop java_throwable) { 425 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 426 VMThread::execute(vm_stop); 427 } 428 429 430 // Check if an external suspend request has completed (or has been 431 // cancelled). Returns true if the thread is externally suspended and 432 // false otherwise. 433 // 434 // The bits parameter returns information about the code path through 435 // the routine. Useful for debugging: 436 // 437 // set in is_ext_suspend_completed(): 438 // 0x00000001 - routine was entered 439 // 0x00000010 - routine return false at end 440 // 0x00000100 - thread exited (return false) 441 // 0x00000200 - suspend request cancelled (return false) 442 // 0x00000400 - thread suspended (return true) 443 // 0x00001000 - thread is in a suspend equivalent state (return true) 444 // 0x00002000 - thread is native and walkable (return true) 445 // 0x00004000 - thread is native_trans and walkable (needed retry) 446 // 447 // set in wait_for_ext_suspend_completion(): 448 // 0x00010000 - routine was entered 449 // 0x00020000 - suspend request cancelled before loop (return false) 450 // 0x00040000 - thread suspended before loop (return true) 451 // 0x00080000 - suspend request cancelled in loop (return false) 452 // 0x00100000 - thread suspended in loop (return true) 453 // 0x00200000 - suspend not completed during retry loop (return false) 454 455 // Helper class for tracing suspend wait debug bits. 456 // 457 // 0x00000100 indicates that the target thread exited before it could 458 // self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 459 // 0x00080000 each indicate a cancelled suspend request so they don't 460 // count as wait failures either. 461 #define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 462 463 class TraceSuspendDebugBits : public StackObj { 464 private: 465 JavaThread * jt; 466 bool is_wait; 467 bool called_by_wait; // meaningful when !is_wait 468 uint32_t * bits; 469 470 public: 471 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 472 uint32_t *_bits) { 473 jt = _jt; 474 is_wait = _is_wait; 475 called_by_wait = _called_by_wait; 476 bits = _bits; 477 } 478 479 ~TraceSuspendDebugBits() { 480 if (!is_wait) { 481 #if 1 482 // By default, don't trace bits for is_ext_suspend_completed() calls. 483 // That trace is very chatty. 484 return; 485 #else 486 if (!called_by_wait) { 487 // If tracing for is_ext_suspend_completed() is enabled, then only 488 // trace calls to it from wait_for_ext_suspend_completion() 489 return; 490 } 491 #endif 492 } 493 494 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 495 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 496 MutexLocker ml(Threads_lock); // needed for get_thread_name() 497 ResourceMark rm; 498 499 tty->print_cr( 500 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 501 jt->get_thread_name(), *bits); 502 503 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 504 } 505 } 506 } 507 }; 508 #undef DEBUG_FALSE_BITS 509 510 511 bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 512 uint32_t *bits) { 513 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 514 515 bool did_trans_retry = false; // only do thread_in_native_trans retry once 516 bool do_trans_retry; // flag to force the retry 517 518 *bits |= 0x00000001; 519 520 do { 521 do_trans_retry = false; 522 523 if (is_exiting()) { 524 // Thread is in the process of exiting. This is always checked 525 // first to reduce the risk of dereferencing a freed JavaThread. 526 *bits |= 0x00000100; 527 return false; 528 } 529 530 if (!is_external_suspend()) { 531 // Suspend request is cancelled. This is always checked before 532 // is_ext_suspended() to reduce the risk of a rogue resume 533 // confusing the thread that made the suspend request. 534 *bits |= 0x00000200; 535 return false; 536 } 537 538 if (is_ext_suspended()) { 539 // thread is suspended 540 *bits |= 0x00000400; 541 return true; 542 } 543 544 // Now that we no longer do hard suspends of threads running 545 // native code, the target thread can be changing thread state 546 // while we are in this routine: 547 // 548 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 549 // 550 // We save a copy of the thread state as observed at this moment 551 // and make our decision about suspend completeness based on the 552 // copy. This closes the race where the thread state is seen as 553 // _thread_in_native_trans in the if-thread_blocked check, but is 554 // seen as _thread_blocked in if-thread_in_native_trans check. 555 JavaThreadState save_state = thread_state(); 556 557 if (save_state == _thread_blocked && is_suspend_equivalent()) { 558 // If the thread's state is _thread_blocked and this blocking 559 // condition is known to be equivalent to a suspend, then we can 560 // consider the thread to be externally suspended. This means that 561 // the code that sets _thread_blocked has been modified to do 562 // self-suspension if the blocking condition releases. We also 563 // used to check for CONDVAR_WAIT here, but that is now covered by 564 // the _thread_blocked with self-suspension check. 565 // 566 // Return true since we wouldn't be here unless there was still an 567 // external suspend request. 568 *bits |= 0x00001000; 569 return true; 570 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 571 // Threads running native code will self-suspend on native==>VM/Java 572 // transitions. If its stack is walkable (should always be the case 573 // unless this function is called before the actual java_suspend() 574 // call), then the wait is done. 575 *bits |= 0x00002000; 576 return true; 577 } else if (!called_by_wait && !did_trans_retry && 578 save_state == _thread_in_native_trans && 579 frame_anchor()->walkable()) { 580 // The thread is transitioning from thread_in_native to another 581 // thread state. check_safepoint_and_suspend_for_native_trans() 582 // will force the thread to self-suspend. If it hasn't gotten 583 // there yet we may have caught the thread in-between the native 584 // code check above and the self-suspend. Lucky us. If we were 585 // called by wait_for_ext_suspend_completion(), then it 586 // will be doing the retries so we don't have to. 587 // 588 // Since we use the saved thread state in the if-statement above, 589 // there is a chance that the thread has already transitioned to 590 // _thread_blocked by the time we get here. In that case, we will 591 // make a single unnecessary pass through the logic below. This 592 // doesn't hurt anything since we still do the trans retry. 593 594 *bits |= 0x00004000; 595 596 // Once the thread leaves thread_in_native_trans for another 597 // thread state, we break out of this retry loop. We shouldn't 598 // need this flag to prevent us from getting back here, but 599 // sometimes paranoia is good. 600 did_trans_retry = true; 601 602 // We wait for the thread to transition to a more usable state. 603 for (int i = 1; i <= SuspendRetryCount; i++) { 604 // We used to do an "os::yield_all(i)" call here with the intention 605 // that yielding would increase on each retry. However, the parameter 606 // is ignored on Linux which means the yield didn't scale up. Waiting 607 // on the SR_lock below provides a much more predictable scale up for 608 // the delay. It also provides a simple/direct point to check for any 609 // safepoint requests from the VMThread 610 611 // temporarily drops SR_lock while doing wait with safepoint check 612 // (if we're a JavaThread - the WatcherThread can also call this) 613 // and increase delay with each retry 614 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 615 616 // check the actual thread state instead of what we saved above 617 if (thread_state() != _thread_in_native_trans) { 618 // the thread has transitioned to another thread state so 619 // try all the checks (except this one) one more time. 620 do_trans_retry = true; 621 break; 622 } 623 } // end retry loop 624 625 626 } 627 } while (do_trans_retry); 628 629 *bits |= 0x00000010; 630 return false; 631 } 632 633 // Wait for an external suspend request to complete (or be cancelled). 634 // Returns true if the thread is externally suspended and false otherwise. 635 // 636 bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 637 uint32_t *bits) { 638 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 639 false /* !called_by_wait */, bits); 640 641 // local flag copies to minimize SR_lock hold time 642 bool is_suspended; 643 bool pending; 644 uint32_t reset_bits; 645 646 // set a marker so is_ext_suspend_completed() knows we are the caller 647 *bits |= 0x00010000; 648 649 // We use reset_bits to reinitialize the bits value at the top of 650 // each retry loop. This allows the caller to make use of any 651 // unused bits for their own marking purposes. 652 reset_bits = *bits; 653 654 { 655 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 656 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 657 delay, bits); 658 pending = is_external_suspend(); 659 } 660 // must release SR_lock to allow suspension to complete 661 662 if (!pending) { 663 // A cancelled suspend request is the only false return from 664 // is_ext_suspend_completed() that keeps us from entering the 665 // retry loop. 666 *bits |= 0x00020000; 667 return false; 668 } 669 670 if (is_suspended) { 671 *bits |= 0x00040000; 672 return true; 673 } 674 675 for (int i = 1; i <= retries; i++) { 676 *bits = reset_bits; // reinit to only track last retry 677 678 // We used to do an "os::yield_all(i)" call here with the intention 679 // that yielding would increase on each retry. However, the parameter 680 // is ignored on Linux which means the yield didn't scale up. Waiting 681 // on the SR_lock below provides a much more predictable scale up for 682 // the delay. It also provides a simple/direct point to check for any 683 // safepoint requests from the VMThread 684 685 { 686 MutexLocker ml(SR_lock()); 687 // wait with safepoint check (if we're a JavaThread - the WatcherThread 688 // can also call this) and increase delay with each retry 689 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 690 691 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 692 delay, bits); 693 694 // It is possible for the external suspend request to be cancelled 695 // (by a resume) before the actual suspend operation is completed. 696 // Refresh our local copy to see if we still need to wait. 697 pending = is_external_suspend(); 698 } 699 700 if (!pending) { 701 // A cancelled suspend request is the only false return from 702 // is_ext_suspend_completed() that keeps us from staying in the 703 // retry loop. 704 *bits |= 0x00080000; 705 return false; 706 } 707 708 if (is_suspended) { 709 *bits |= 0x00100000; 710 return true; 711 } 712 } // end retry loop 713 714 // thread did not suspend after all our retries 715 *bits |= 0x00200000; 716 return false; 717 } 718 719 #ifndef PRODUCT 720 void JavaThread::record_jump(address target, address instr, const char* file, 721 int line) { 722 723 // This should not need to be atomic as the only way for simultaneous 724 // updates is via interrupts. Even then this should be rare or non-existent 725 // and we don't care that much anyway. 726 727 int index = _jmp_ring_index; 728 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 729 _jmp_ring[index]._target = (intptr_t) target; 730 _jmp_ring[index]._instruction = (intptr_t) instr; 731 _jmp_ring[index]._file = file; 732 _jmp_ring[index]._line = line; 733 } 734 #endif // PRODUCT 735 736 // Called by flat profiler 737 // Callers have already called wait_for_ext_suspend_completion 738 // The assertion for that is currently too complex to put here: 739 bool JavaThread::profile_last_Java_frame(frame* _fr) { 740 bool gotframe = false; 741 // self suspension saves needed state. 742 if (has_last_Java_frame() && _anchor.walkable()) { 743 *_fr = pd_last_frame(); 744 gotframe = true; 745 } 746 return gotframe; 747 } 748 749 void Thread::interrupt(Thread* thread) { 750 debug_only(check_for_dangling_thread_pointer(thread);) 751 os::interrupt(thread); 752 } 753 754 bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 755 debug_only(check_for_dangling_thread_pointer(thread);) 756 // Note: If clear_interrupted==false, this simply fetches and 757 // returns the value of the field osthread()->interrupted(). 758 return os::is_interrupted(thread, clear_interrupted); 759 } 760 761 762 // GC Support 763 bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 764 jint thread_parity = _oops_do_parity; 765 if (thread_parity != strong_roots_parity) { 766 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 767 if (res == thread_parity) { 768 return true; 769 } else { 770 guarantee(res == strong_roots_parity, "Or else what?"); 771 return false; 772 } 773 } 774 return false; 775 } 776 777 void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 778 active_handles()->oops_do(f); 779 // Do oop for ThreadShadow 780 f->do_oop((oop*)&_pending_exception); 781 handle_area()->oops_do(f); 782 } 783 784 void Thread::nmethods_do(CodeBlobClosure* cf) { 785 // no nmethods in a generic thread... 786 } 787 788 void Thread::metadata_handles_do(void f(Metadata*)) { 789 // Only walk the Handles in Thread. 790 if (metadata_handles() != NULL) { 791 for (int i = 0; i< metadata_handles()->length(); i++) { 792 f(metadata_handles()->at(i)); 793 } 794 } 795 } 796 797 void Thread::print_on(outputStream* st) const { 798 // get_priority assumes osthread initialized 799 if (osthread() != NULL) { 800 int os_prio; 801 if (os::get_native_priority(this, &os_prio) == OS_OK) { 802 st->print("os_prio=%d ", os_prio); 803 } 804 st->print("tid=" INTPTR_FORMAT " ", p2i(this)); 805 ext().print_on(st); 806 osthread()->print_on(st); 807 } 808 debug_only(if (WizardMode) print_owned_locks_on(st);) 809 } 810 811 // Thread::print_on_error() is called by fatal error handler. Don't use 812 // any lock or allocate memory. 813 void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 814 if (is_VM_thread()) st->print("VMThread"); 815 else if (is_Compiler_thread()) st->print("CompilerThread"); 816 else if (is_Java_thread()) st->print("JavaThread"); 817 else if (is_GC_task_thread()) st->print("GCTaskThread"); 818 else if (is_Watcher_thread()) st->print("WatcherThread"); 819 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 820 else st->print("Thread"); 821 822 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 823 p2i(_stack_base - _stack_size), p2i(_stack_base)); 824 825 if (osthread()) { 826 st->print(" [id=%d]", osthread()->thread_id()); 827 } 828 } 829 830 #ifdef ASSERT 831 void Thread::print_owned_locks_on(outputStream* st) const { 832 Monitor *cur = _owned_locks; 833 if (cur == NULL) { 834 st->print(" (no locks) "); 835 } else { 836 st->print_cr(" Locks owned:"); 837 while (cur) { 838 cur->print_on(st); 839 cur = cur->next(); 840 } 841 } 842 } 843 844 static int ref_use_count = 0; 845 846 bool Thread::owns_locks_but_compiled_lock() const { 847 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 848 if (cur != Compile_lock) return true; 849 } 850 return false; 851 } 852 853 854 #endif 855 856 #ifndef PRODUCT 857 858 // The flag: potential_vm_operation notifies if this particular safepoint state could potential 859 // invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 860 // no threads which allow_vm_block's are held 861 void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 862 // Check if current thread is allowed to block at a safepoint 863 if (!(_allow_safepoint_count == 0)) { 864 fatal("Possible safepoint reached by thread that does not allow it"); 865 } 866 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 867 fatal("LEAF method calling lock?"); 868 } 869 870 #ifdef ASSERT 871 if (potential_vm_operation && is_Java_thread() 872 && !Universe::is_bootstrapping()) { 873 // Make sure we do not hold any locks that the VM thread also uses. 874 // This could potentially lead to deadlocks 875 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 876 // Threads_lock is special, since the safepoint synchronization will not start before this is 877 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 878 // since it is used to transfer control between JavaThreads and the VMThread 879 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 880 if ((cur->allow_vm_block() && 881 cur != Threads_lock && 882 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 883 cur != VMOperationRequest_lock && 884 cur != VMOperationQueue_lock) || 885 cur->rank() == Mutex::special) { 886 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 887 } 888 } 889 } 890 891 if (GCALotAtAllSafepoints) { 892 // We could enter a safepoint here and thus have a gc 893 InterfaceSupport::check_gc_alot(); 894 } 895 #endif 896 } 897 #endif 898 899 bool Thread::is_in_stack(address adr) const { 900 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 901 address end = os::current_stack_pointer(); 902 // Allow non Java threads to call this without stack_base 903 if (_stack_base == NULL) return true; 904 if (stack_base() >= adr && adr >= end) return true; 905 906 return false; 907 } 908 909 910 bool Thread::is_in_usable_stack(address adr) const { 911 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 912 size_t usable_stack_size = _stack_size - stack_guard_size; 913 914 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 915 } 916 917 918 // We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 919 // However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 920 // used for compilation in the future. If that change is made, the need for these methods 921 // should be revisited, and they should be removed if possible. 922 923 bool Thread::is_lock_owned(address adr) const { 924 return on_local_stack(adr); 925 } 926 927 bool Thread::set_as_starting_thread() { 928 // NOTE: this must be called inside the main thread. 929 return os::create_main_thread((JavaThread*)this); 930 } 931 932 static void initialize_class(Symbol* class_name, TRAPS) { 933 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 934 InstanceKlass::cast(klass)->initialize(CHECK); 935 } 936 937 938 // Creates the initial ThreadGroup 939 static Handle create_initial_thread_group(TRAPS) { 940 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 941 instanceKlassHandle klass (THREAD, k); 942 943 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 944 { 945 JavaValue result(T_VOID); 946 JavaCalls::call_special(&result, 947 system_instance, 948 klass, 949 vmSymbols::object_initializer_name(), 950 vmSymbols::void_method_signature(), 951 CHECK_NH); 952 } 953 Universe::set_system_thread_group(system_instance()); 954 955 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 956 { 957 JavaValue result(T_VOID); 958 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 959 JavaCalls::call_special(&result, 960 main_instance, 961 klass, 962 vmSymbols::object_initializer_name(), 963 vmSymbols::threadgroup_string_void_signature(), 964 system_instance, 965 string, 966 CHECK_NH); 967 } 968 return main_instance; 969 } 970 971 // Creates the initial Thread 972 static oop create_initial_thread(Handle thread_group, JavaThread* thread, 973 TRAPS) { 974 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 975 instanceKlassHandle klass (THREAD, k); 976 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 977 978 java_lang_Thread::set_thread(thread_oop(), thread); 979 java_lang_Thread::set_priority(thread_oop(), NormPriority); 980 thread->set_threadObj(thread_oop()); 981 982 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 983 984 JavaValue result(T_VOID); 985 JavaCalls::call_special(&result, thread_oop, 986 klass, 987 vmSymbols::object_initializer_name(), 988 vmSymbols::threadgroup_string_void_signature(), 989 thread_group, 990 string, 991 CHECK_NULL); 992 return thread_oop(); 993 } 994 995 static void call_initializeSystemClass(TRAPS) { 996 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 997 instanceKlassHandle klass (THREAD, k); 998 999 JavaValue result(T_VOID); 1000 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1001 vmSymbols::void_method_signature(), CHECK); 1002 } 1003 1004 char java_runtime_name[128] = ""; 1005 char java_runtime_version[128] = ""; 1006 1007 // extract the JRE name from sun.misc.Version.java_runtime_name 1008 static const char* get_java_runtime_name(TRAPS) { 1009 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1010 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1011 fieldDescriptor fd; 1012 bool found = k != NULL && 1013 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1014 vmSymbols::string_signature(), &fd); 1015 if (found) { 1016 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1017 if (name_oop == NULL) { 1018 return NULL; 1019 } 1020 const char* name = java_lang_String::as_utf8_string(name_oop, 1021 java_runtime_name, 1022 sizeof(java_runtime_name)); 1023 return name; 1024 } else { 1025 return NULL; 1026 } 1027 } 1028 1029 // extract the JRE version from sun.misc.Version.java_runtime_version 1030 static const char* get_java_runtime_version(TRAPS) { 1031 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1032 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1033 fieldDescriptor fd; 1034 bool found = k != NULL && 1035 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1036 vmSymbols::string_signature(), &fd); 1037 if (found) { 1038 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1039 if (name_oop == NULL) { 1040 return NULL; 1041 } 1042 const char* name = java_lang_String::as_utf8_string(name_oop, 1043 java_runtime_version, 1044 sizeof(java_runtime_version)); 1045 return name; 1046 } else { 1047 return NULL; 1048 } 1049 } 1050 1051 // General purpose hook into Java code, run once when the VM is initialized. 1052 // The Java library method itself may be changed independently from the VM. 1053 static void call_postVMInitHook(TRAPS) { 1054 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1055 instanceKlassHandle klass (THREAD, k); 1056 if (klass.not_null()) { 1057 JavaValue result(T_VOID); 1058 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1059 vmSymbols::void_method_signature(), 1060 CHECK); 1061 } 1062 } 1063 1064 static void reset_vm_info_property(TRAPS) { 1065 // the vm info string 1066 ResourceMark rm(THREAD); 1067 const char *vm_info = VM_Version::vm_info_string(); 1068 1069 // java.lang.System class 1070 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1071 instanceKlassHandle klass (THREAD, k); 1072 1073 // setProperty arguments 1074 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1075 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1076 1077 // return value 1078 JavaValue r(T_OBJECT); 1079 1080 // public static String setProperty(String key, String value); 1081 JavaCalls::call_static(&r, 1082 klass, 1083 vmSymbols::setProperty_name(), 1084 vmSymbols::string_string_string_signature(), 1085 key_str, 1086 value_str, 1087 CHECK); 1088 } 1089 1090 1091 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 1092 bool daemon, TRAPS) { 1093 assert(thread_group.not_null(), "thread group should be specified"); 1094 assert(threadObj() == NULL, "should only create Java thread object once"); 1095 1096 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1097 instanceKlassHandle klass (THREAD, k); 1098 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1099 1100 java_lang_Thread::set_thread(thread_oop(), this); 1101 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1102 set_threadObj(thread_oop()); 1103 1104 JavaValue result(T_VOID); 1105 if (thread_name != NULL) { 1106 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1107 // Thread gets assigned specified name and null target 1108 JavaCalls::call_special(&result, 1109 thread_oop, 1110 klass, 1111 vmSymbols::object_initializer_name(), 1112 vmSymbols::threadgroup_string_void_signature(), 1113 thread_group, // Argument 1 1114 name, // Argument 2 1115 THREAD); 1116 } else { 1117 // Thread gets assigned name "Thread-nnn" and null target 1118 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1119 JavaCalls::call_special(&result, 1120 thread_oop, 1121 klass, 1122 vmSymbols::object_initializer_name(), 1123 vmSymbols::threadgroup_runnable_void_signature(), 1124 thread_group, // Argument 1 1125 Handle(), // Argument 2 1126 THREAD); 1127 } 1128 1129 1130 if (daemon) { 1131 java_lang_Thread::set_daemon(thread_oop()); 1132 } 1133 1134 if (HAS_PENDING_EXCEPTION) { 1135 return; 1136 } 1137 1138 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass()); 1139 Handle threadObj(THREAD, this->threadObj()); 1140 1141 JavaCalls::call_special(&result, 1142 thread_group, 1143 group, 1144 vmSymbols::add_method_name(), 1145 vmSymbols::thread_void_signature(), 1146 threadObj, // Arg 1 1147 THREAD); 1148 } 1149 1150 // NamedThread -- non-JavaThread subclasses with multiple 1151 // uniquely named instances should derive from this. 1152 NamedThread::NamedThread() : Thread() { 1153 _name = NULL; 1154 _processed_thread = NULL; 1155 _gc_id = GCId::undefined(); 1156 } 1157 1158 NamedThread::~NamedThread() { 1159 if (_name != NULL) { 1160 FREE_C_HEAP_ARRAY(char, _name); 1161 _name = NULL; 1162 } 1163 } 1164 1165 void NamedThread::set_name(const char* format, ...) { 1166 guarantee(_name == NULL, "Only get to set name once."); 1167 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1168 guarantee(_name != NULL, "alloc failure"); 1169 va_list ap; 1170 va_start(ap, format); 1171 jio_vsnprintf(_name, max_name_len, format, ap); 1172 va_end(ap); 1173 } 1174 1175 void NamedThread::initialize_named_thread() { 1176 set_native_thread_name(name()); 1177 } 1178 1179 void NamedThread::print_on(outputStream* st) const { 1180 st->print("\"%s\" ", name()); 1181 Thread::print_on(st); 1182 st->cr(); 1183 } 1184 1185 1186 // ======= WatcherThread ======== 1187 1188 // The watcher thread exists to simulate timer interrupts. It should 1189 // be replaced by an abstraction over whatever native support for 1190 // timer interrupts exists on the platform. 1191 1192 WatcherThread* WatcherThread::_watcher_thread = NULL; 1193 bool WatcherThread::_startable = false; 1194 volatile bool WatcherThread::_should_terminate = false; 1195 1196 WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1197 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1198 if (os::create_thread(this, os::watcher_thread)) { 1199 _watcher_thread = this; 1200 1201 // Set the watcher thread to the highest OS priority which should not be 1202 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1203 // is created. The only normal thread using this priority is the reference 1204 // handler thread, which runs for very short intervals only. 1205 // If the VMThread's priority is not lower than the WatcherThread profiling 1206 // will be inaccurate. 1207 os::set_priority(this, MaxPriority); 1208 if (!DisableStartThread) { 1209 os::start_thread(this); 1210 } 1211 } 1212 } 1213 1214 int WatcherThread::sleep() const { 1215 // The WatcherThread does not participate in the safepoint protocol 1216 // for the PeriodicTask_lock because it is not a JavaThread. 1217 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1218 1219 if (_should_terminate) { 1220 // check for termination before we do any housekeeping or wait 1221 return 0; // we did not sleep. 1222 } 1223 1224 // remaining will be zero if there are no tasks, 1225 // causing the WatcherThread to sleep until a task is 1226 // enrolled 1227 int remaining = PeriodicTask::time_to_wait(); 1228 int time_slept = 0; 1229 1230 // we expect this to timeout - we only ever get unparked when 1231 // we should terminate or when a new task has been enrolled 1232 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1233 1234 jlong time_before_loop = os::javaTimeNanos(); 1235 1236 while (true) { 1237 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, 1238 remaining); 1239 jlong now = os::javaTimeNanos(); 1240 1241 if (remaining == 0) { 1242 // if we didn't have any tasks we could have waited for a long time 1243 // consider the time_slept zero and reset time_before_loop 1244 time_slept = 0; 1245 time_before_loop = now; 1246 } else { 1247 // need to recalculate since we might have new tasks in _tasks 1248 time_slept = (int) ((now - time_before_loop) / 1000000); 1249 } 1250 1251 // Change to task list or spurious wakeup of some kind 1252 if (timedout || _should_terminate) { 1253 break; 1254 } 1255 1256 remaining = PeriodicTask::time_to_wait(); 1257 if (remaining == 0) { 1258 // Last task was just disenrolled so loop around and wait until 1259 // another task gets enrolled 1260 continue; 1261 } 1262 1263 remaining -= time_slept; 1264 if (remaining <= 0) { 1265 break; 1266 } 1267 } 1268 1269 return time_slept; 1270 } 1271 1272 void WatcherThread::run() { 1273 assert(this == watcher_thread(), "just checking"); 1274 1275 this->record_stack_base_and_size(); 1276 this->initialize_thread_local_storage(); 1277 this->set_native_thread_name(this->name()); 1278 this->set_active_handles(JNIHandleBlock::allocate_block()); 1279 while (true) { 1280 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1281 assert(watcher_thread() == this, "thread consistency check"); 1282 1283 // Calculate how long it'll be until the next PeriodicTask work 1284 // should be done, and sleep that amount of time. 1285 int time_waited = sleep(); 1286 1287 if (is_error_reported()) { 1288 // A fatal error has happened, the error handler(VMError::report_and_die) 1289 // should abort JVM after creating an error log file. However in some 1290 // rare cases, the error handler itself might deadlock. Here we try to 1291 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1292 // 1293 // This code is in WatcherThread because WatcherThread wakes up 1294 // periodically so the fatal error handler doesn't need to do anything; 1295 // also because the WatcherThread is less likely to crash than other 1296 // threads. 1297 1298 for (;;) { 1299 if (!ShowMessageBoxOnError 1300 && (OnError == NULL || OnError[0] == '\0') 1301 && Arguments::abort_hook() == NULL) { 1302 os::sleep(this, ErrorLogTimeout * 60 * 1000, false); 1303 fdStream err(defaultStream::output_fd()); 1304 err.print_raw_cr("# [ timer expired, abort... ]"); 1305 // skip atexit/vm_exit/vm_abort hooks 1306 os::die(); 1307 } 1308 1309 // Wake up 5 seconds later, the fatal handler may reset OnError or 1310 // ShowMessageBoxOnError when it is ready to abort. 1311 os::sleep(this, 5 * 1000, false); 1312 } 1313 } 1314 1315 if (_should_terminate) { 1316 // check for termination before posting the next tick 1317 break; 1318 } 1319 1320 PeriodicTask::real_time_tick(time_waited); 1321 } 1322 1323 // Signal that it is terminated 1324 { 1325 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1326 _watcher_thread = NULL; 1327 Terminator_lock->notify(); 1328 } 1329 1330 // Thread destructor usually does this.. 1331 ThreadLocalStorage::set_thread(NULL); 1332 } 1333 1334 void WatcherThread::start() { 1335 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1336 1337 if (watcher_thread() == NULL && _startable) { 1338 _should_terminate = false; 1339 // Create the single instance of WatcherThread 1340 new WatcherThread(); 1341 } 1342 } 1343 1344 void WatcherThread::make_startable() { 1345 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1346 _startable = true; 1347 } 1348 1349 void WatcherThread::stop() { 1350 { 1351 // Follow normal safepoint aware lock enter protocol since the 1352 // WatcherThread is stopped by another JavaThread. 1353 MutexLocker ml(PeriodicTask_lock); 1354 _should_terminate = true; 1355 1356 WatcherThread* watcher = watcher_thread(); 1357 if (watcher != NULL) { 1358 // unpark the WatcherThread so it can see that it should terminate 1359 watcher->unpark(); 1360 } 1361 } 1362 1363 MutexLocker mu(Terminator_lock); 1364 1365 while (watcher_thread() != NULL) { 1366 // This wait should make safepoint checks, wait without a timeout, 1367 // and wait as a suspend-equivalent condition. 1368 // 1369 // Note: If the FlatProfiler is running, then this thread is waiting 1370 // for the WatcherThread to terminate and the WatcherThread, via the 1371 // FlatProfiler task, is waiting for the external suspend request on 1372 // this thread to complete. wait_for_ext_suspend_completion() will 1373 // eventually timeout, but that takes time. Making this wait a 1374 // suspend-equivalent condition solves that timeout problem. 1375 // 1376 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1377 Mutex::_as_suspend_equivalent_flag); 1378 } 1379 } 1380 1381 void WatcherThread::unpark() { 1382 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1383 PeriodicTask_lock->notify(); 1384 } 1385 1386 void WatcherThread::print_on(outputStream* st) const { 1387 st->print("\"%s\" ", name()); 1388 Thread::print_on(st); 1389 st->cr(); 1390 } 1391 1392 // ======= JavaThread ======== 1393 1394 #if INCLUDE_JVMCI 1395 1396 jlong* JavaThread::_jvmci_old_thread_counters; 1397 1398 bool jvmci_counters_include(JavaThread* thread) { 1399 oop threadObj = thread->threadObj(); 1400 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); 1401 } 1402 1403 void JavaThread::collect_counters(typeArrayOop array) { 1404 if (JVMCICounterSize > 0) { 1405 MutexLocker tl(Threads_lock); 1406 for (int i = 0; i < array->length(); i++) { 1407 array->long_at_put(i, _jvmci_old_thread_counters[i]); 1408 } 1409 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) { 1410 if (jvmci_counters_include(tp)) { 1411 for (int i = 0; i < array->length(); i++) { 1412 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]); 1413 } 1414 } 1415 } 1416 } 1417 } 1418 1419 #endif // INCLUDE_JVMCI 1420 1421 // A JavaThread is a normal Java thread 1422 1423 void JavaThread::initialize() { 1424 // Initialize fields 1425 1426 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1427 set_claimed_par_id(UINT_MAX); 1428 1429 set_saved_exception_pc(NULL); 1430 set_threadObj(NULL); 1431 _anchor.clear(); 1432 set_entry_point(NULL); 1433 set_jni_functions(jni_functions()); 1434 set_callee_target(NULL); 1435 set_vm_result(NULL); 1436 set_vm_result_2(NULL); 1437 set_vframe_array_head(NULL); 1438 set_vframe_array_last(NULL); 1439 set_deferred_locals(NULL); 1440 set_deopt_mark(NULL); 1441 set_deopt_nmethod(NULL); 1442 clear_must_deopt_id(); 1443 set_monitor_chunks(NULL); 1444 set_next(NULL); 1445 set_thread_state(_thread_new); 1446 _terminated = _not_terminated; 1447 _privileged_stack_top = NULL; 1448 _array_for_gc = NULL; 1449 _suspend_equivalent = false; 1450 _in_deopt_handler = 0; 1451 _doing_unsafe_access = false; 1452 _stack_guard_state = stack_guard_unused; 1453 #if INCLUDE_JVMCI 1454 _pending_monitorenter = false; 1455 _pending_deoptimization = -1; 1456 _pending_failed_speculation = NULL; 1457 _pending_transfer_to_interpreter = false; 1458 _jvmci._alternate_call_target = NULL; 1459 assert(_jvmci._implicit_exception_pc == NULL, "must be"); 1460 if (JVMCICounterSize > 0) { 1461 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 1462 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize); 1463 } else { 1464 _jvmci_counters = NULL; 1465 } 1466 #endif // INCLUDE_JVMCI 1467 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1468 _exception_pc = 0; 1469 _exception_handler_pc = 0; 1470 _is_method_handle_return = 0; 1471 _jvmti_thread_state= NULL; 1472 _should_post_on_exceptions_flag = JNI_FALSE; 1473 _jvmti_get_loaded_classes_closure = NULL; 1474 _interp_only_mode = 0; 1475 _special_runtime_exit_condition = _no_async_condition; 1476 _pending_async_exception = NULL; 1477 _thread_stat = NULL; 1478 _thread_stat = new ThreadStatistics(); 1479 _blocked_on_compilation = false; 1480 _jni_active_critical = 0; 1481 _pending_jni_exception_check_fn = NULL; 1482 _do_not_unlock_if_synchronized = false; 1483 _cached_monitor_info = NULL; 1484 _parker = Parker::Allocate(this); 1485 1486 #ifndef PRODUCT 1487 _jmp_ring_index = 0; 1488 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1489 record_jump(NULL, NULL, NULL, 0); 1490 } 1491 #endif // PRODUCT 1492 1493 set_thread_profiler(NULL); 1494 if (FlatProfiler::is_active()) { 1495 // This is where we would decide to either give each thread it's own profiler 1496 // or use one global one from FlatProfiler, 1497 // or up to some count of the number of profiled threads, etc. 1498 ThreadProfiler* pp = new ThreadProfiler(); 1499 pp->engage(); 1500 set_thread_profiler(pp); 1501 } 1502 1503 // Setup safepoint state info for this thread 1504 ThreadSafepointState::create(this); 1505 1506 debug_only(_java_call_counter = 0); 1507 1508 // JVMTI PopFrame support 1509 _popframe_condition = popframe_inactive; 1510 _popframe_preserved_args = NULL; 1511 _popframe_preserved_args_size = 0; 1512 _frames_to_pop_failed_realloc = 0; 1513 1514 pd_initialize(); 1515 } 1516 1517 #if INCLUDE_ALL_GCS 1518 SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1519 DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1520 #endif // INCLUDE_ALL_GCS 1521 1522 JavaThread::JavaThread(bool is_attaching_via_jni) : 1523 Thread() 1524 #if INCLUDE_ALL_GCS 1525 , _satb_mark_queue(&_satb_mark_queue_set), 1526 _dirty_card_queue(&_dirty_card_queue_set) 1527 #endif // INCLUDE_ALL_GCS 1528 { 1529 initialize(); 1530 if (is_attaching_via_jni) { 1531 _jni_attach_state = _attaching_via_jni; 1532 } else { 1533 _jni_attach_state = _not_attaching_via_jni; 1534 } 1535 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1536 } 1537 1538 bool JavaThread::reguard_stack(address cur_sp) { 1539 if (_stack_guard_state != stack_guard_yellow_disabled) { 1540 return true; // Stack already guarded or guard pages not needed. 1541 } 1542 1543 if (register_stack_overflow()) { 1544 // For those architectures which have separate register and 1545 // memory stacks, we must check the register stack to see if 1546 // it has overflowed. 1547 return false; 1548 } 1549 1550 // Java code never executes within the yellow zone: the latter is only 1551 // there to provoke an exception during stack banging. If java code 1552 // is executing there, either StackShadowPages should be larger, or 1553 // some exception code in c1, c2 or the interpreter isn't unwinding 1554 // when it should. 1555 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1556 1557 enable_stack_yellow_zone(); 1558 return true; 1559 } 1560 1561 bool JavaThread::reguard_stack(void) { 1562 return reguard_stack(os::current_stack_pointer()); 1563 } 1564 1565 1566 void JavaThread::block_if_vm_exited() { 1567 if (_terminated == _vm_exited) { 1568 // _vm_exited is set at safepoint, and Threads_lock is never released 1569 // we will block here forever 1570 Threads_lock->lock_without_safepoint_check(); 1571 ShouldNotReachHere(); 1572 } 1573 } 1574 1575 1576 // Remove this ifdef when C1 is ported to the compiler interface. 1577 static void compiler_thread_entry(JavaThread* thread, TRAPS); 1578 static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1579 1580 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1581 Thread() 1582 #if INCLUDE_ALL_GCS 1583 , _satb_mark_queue(&_satb_mark_queue_set), 1584 _dirty_card_queue(&_dirty_card_queue_set) 1585 #endif // INCLUDE_ALL_GCS 1586 { 1587 initialize(); 1588 _jni_attach_state = _not_attaching_via_jni; 1589 set_entry_point(entry_point); 1590 // Create the native thread itself. 1591 // %note runtime_23 1592 os::ThreadType thr_type = os::java_thread; 1593 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1594 os::java_thread; 1595 os::create_thread(this, thr_type, stack_sz); 1596 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1597 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1598 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1599 // the exception consists of creating the exception object & initializing it, initialization 1600 // will leave the VM via a JavaCall and then all locks must be unlocked). 1601 // 1602 // The thread is still suspended when we reach here. Thread must be explicit started 1603 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1604 // by calling Threads:add. The reason why this is not done here, is because the thread 1605 // object must be fully initialized (take a look at JVM_Start) 1606 } 1607 1608 JavaThread::~JavaThread() { 1609 1610 // JSR166 -- return the parker to the free list 1611 Parker::Release(_parker); 1612 _parker = NULL; 1613 1614 // Free any remaining previous UnrollBlock 1615 vframeArray* old_array = vframe_array_last(); 1616 1617 if (old_array != NULL) { 1618 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1619 old_array->set_unroll_block(NULL); 1620 delete old_info; 1621 delete old_array; 1622 } 1623 1624 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1625 if (deferred != NULL) { 1626 // This can only happen if thread is destroyed before deoptimization occurs. 1627 assert(deferred->length() != 0, "empty array!"); 1628 do { 1629 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1630 deferred->remove_at(0); 1631 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1632 delete dlv; 1633 } while (deferred->length() != 0); 1634 delete deferred; 1635 } 1636 1637 // All Java related clean up happens in exit 1638 ThreadSafepointState::destroy(this); 1639 if (_thread_profiler != NULL) delete _thread_profiler; 1640 if (_thread_stat != NULL) delete _thread_stat; 1641 1642 #if INCLUDE_JVMCI 1643 if (JVMCICounterSize > 0) { 1644 if (jvmci_counters_include(this)) { 1645 for (int i = 0; i < JVMCICounterSize; i++) { 1646 _jvmci_old_thread_counters[i] += _jvmci_counters[i]; 1647 } 1648 } 1649 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); 1650 } 1651 #endif // INCLUDE_JVMCI 1652 } 1653 1654 1655 // The first routine called by a new Java thread 1656 void JavaThread::run() { 1657 // initialize thread-local alloc buffer related fields 1658 this->initialize_tlab(); 1659 1660 // used to test validity of stack trace backs 1661 this->record_base_of_stack_pointer(); 1662 1663 // Record real stack base and size. 1664 this->record_stack_base_and_size(); 1665 1666 // Initialize thread local storage; set before calling MutexLocker 1667 this->initialize_thread_local_storage(); 1668 1669 this->create_stack_guard_pages(); 1670 1671 this->cache_global_variables(); 1672 1673 // Thread is now sufficient initialized to be handled by the safepoint code as being 1674 // in the VM. Change thread state from _thread_new to _thread_in_vm 1675 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1676 1677 assert(JavaThread::current() == this, "sanity check"); 1678 assert(!Thread::current()->owns_locks(), "sanity check"); 1679 1680 DTRACE_THREAD_PROBE(start, this); 1681 1682 // This operation might block. We call that after all safepoint checks for a new thread has 1683 // been completed. 1684 this->set_active_handles(JNIHandleBlock::allocate_block()); 1685 1686 if (JvmtiExport::should_post_thread_life()) { 1687 JvmtiExport::post_thread_start(this); 1688 } 1689 1690 EventThreadStart event; 1691 if (event.should_commit()) { 1692 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1693 event.commit(); 1694 } 1695 1696 // We call another function to do the rest so we are sure that the stack addresses used 1697 // from there will be lower than the stack base just computed 1698 thread_main_inner(); 1699 1700 // Note, thread is no longer valid at this point! 1701 } 1702 1703 1704 void JavaThread::thread_main_inner() { 1705 assert(JavaThread::current() == this, "sanity check"); 1706 assert(this->threadObj() != NULL, "just checking"); 1707 1708 // Execute thread entry point unless this thread has a pending exception 1709 // or has been stopped before starting. 1710 // Note: Due to JVM_StopThread we can have pending exceptions already! 1711 if (!this->has_pending_exception() && 1712 !java_lang_Thread::is_stillborn(this->threadObj())) { 1713 { 1714 ResourceMark rm(this); 1715 this->set_native_thread_name(this->get_thread_name()); 1716 } 1717 HandleMark hm(this); 1718 this->entry_point()(this, this); 1719 } 1720 1721 DTRACE_THREAD_PROBE(stop, this); 1722 1723 this->exit(false); 1724 delete this; 1725 } 1726 1727 1728 static void ensure_join(JavaThread* thread) { 1729 // We do not need to grap the Threads_lock, since we are operating on ourself. 1730 Handle threadObj(thread, thread->threadObj()); 1731 assert(threadObj.not_null(), "java thread object must exist"); 1732 ObjectLocker lock(threadObj, thread); 1733 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1734 thread->clear_pending_exception(); 1735 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1736 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1737 // Clear the native thread instance - this makes isAlive return false and allows the join() 1738 // to complete once we've done the notify_all below 1739 java_lang_Thread::set_thread(threadObj(), NULL); 1740 lock.notify_all(thread); 1741 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1742 thread->clear_pending_exception(); 1743 } 1744 1745 1746 // For any new cleanup additions, please check to see if they need to be applied to 1747 // cleanup_failed_attach_current_thread as well. 1748 void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1749 assert(this == JavaThread::current(), "thread consistency check"); 1750 1751 HandleMark hm(this); 1752 Handle uncaught_exception(this, this->pending_exception()); 1753 this->clear_pending_exception(); 1754 Handle threadObj(this, this->threadObj()); 1755 assert(threadObj.not_null(), "Java thread object should be created"); 1756 1757 if (get_thread_profiler() != NULL) { 1758 get_thread_profiler()->disengage(); 1759 ResourceMark rm; 1760 get_thread_profiler()->print(get_thread_name()); 1761 } 1762 1763 1764 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1765 { 1766 EXCEPTION_MARK; 1767 1768 CLEAR_PENDING_EXCEPTION; 1769 } 1770 if (!destroy_vm) { 1771 if (uncaught_exception.not_null()) { 1772 EXCEPTION_MARK; 1773 // Call method Thread.dispatchUncaughtException(). 1774 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1775 JavaValue result(T_VOID); 1776 JavaCalls::call_virtual(&result, 1777 threadObj, thread_klass, 1778 vmSymbols::dispatchUncaughtException_name(), 1779 vmSymbols::throwable_void_signature(), 1780 uncaught_exception, 1781 THREAD); 1782 if (HAS_PENDING_EXCEPTION) { 1783 ResourceMark rm(this); 1784 jio_fprintf(defaultStream::error_stream(), 1785 "\nException: %s thrown from the UncaughtExceptionHandler" 1786 " in thread \"%s\"\n", 1787 pending_exception()->klass()->external_name(), 1788 get_thread_name()); 1789 CLEAR_PENDING_EXCEPTION; 1790 } 1791 } 1792 1793 // Called before the java thread exit since we want to read info 1794 // from java_lang_Thread object 1795 EventThreadEnd event; 1796 if (event.should_commit()) { 1797 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1798 event.commit(); 1799 } 1800 1801 // Call after last event on thread 1802 EVENT_THREAD_EXIT(this); 1803 1804 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1805 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1806 // is deprecated anyhow. 1807 if (!is_Compiler_thread()) { 1808 int count = 3; 1809 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1810 EXCEPTION_MARK; 1811 JavaValue result(T_VOID); 1812 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1813 JavaCalls::call_virtual(&result, 1814 threadObj, thread_klass, 1815 vmSymbols::exit_method_name(), 1816 vmSymbols::void_method_signature(), 1817 THREAD); 1818 CLEAR_PENDING_EXCEPTION; 1819 } 1820 } 1821 // notify JVMTI 1822 if (JvmtiExport::should_post_thread_life()) { 1823 JvmtiExport::post_thread_end(this); 1824 } 1825 1826 // We have notified the agents that we are exiting, before we go on, 1827 // we must check for a pending external suspend request and honor it 1828 // in order to not surprise the thread that made the suspend request. 1829 while (true) { 1830 { 1831 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1832 if (!is_external_suspend()) { 1833 set_terminated(_thread_exiting); 1834 ThreadService::current_thread_exiting(this); 1835 break; 1836 } 1837 // Implied else: 1838 // Things get a little tricky here. We have a pending external 1839 // suspend request, but we are holding the SR_lock so we 1840 // can't just self-suspend. So we temporarily drop the lock 1841 // and then self-suspend. 1842 } 1843 1844 ThreadBlockInVM tbivm(this); 1845 java_suspend_self(); 1846 1847 // We're done with this suspend request, but we have to loop around 1848 // and check again. Eventually we will get SR_lock without a pending 1849 // external suspend request and will be able to mark ourselves as 1850 // exiting. 1851 } 1852 // no more external suspends are allowed at this point 1853 } else { 1854 // before_exit() has already posted JVMTI THREAD_END events 1855 } 1856 1857 // Notify waiters on thread object. This has to be done after exit() is called 1858 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1859 // group should have the destroyed bit set before waiters are notified). 1860 ensure_join(this); 1861 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1862 1863 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1864 // held by this thread must be released. The spec does not distinguish 1865 // between JNI-acquired and regular Java monitors. We can only see 1866 // regular Java monitors here if monitor enter-exit matching is broken. 1867 // 1868 // Optionally release any monitors for regular JavaThread exits. This 1869 // is provided as a work around for any bugs in monitor enter-exit 1870 // matching. This can be expensive so it is not enabled by default. 1871 // ObjectMonitor::Knob_ExitRelease is a superset of the 1872 // JNIDetachReleasesMonitors option. 1873 // 1874 // ensure_join() ignores IllegalThreadStateExceptions, and so does 1875 // ObjectSynchronizer::release_monitors_owned_by_thread(). 1876 if ((exit_type == jni_detach && JNIDetachReleasesMonitors) || 1877 ObjectMonitor::Knob_ExitRelease) { 1878 // Sanity check even though JNI DetachCurrentThread() would have 1879 // returned JNI_ERR if there was a Java frame. JavaThread exit 1880 // should be done executing Java code by the time we get here. 1881 assert(!this->has_last_Java_frame(), 1882 "should not have a Java frame when detaching or exiting"); 1883 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1884 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1885 } 1886 1887 // These things needs to be done while we are still a Java Thread. Make sure that thread 1888 // is in a consistent state, in case GC happens 1889 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1890 1891 if (active_handles() != NULL) { 1892 JNIHandleBlock* block = active_handles(); 1893 set_active_handles(NULL); 1894 JNIHandleBlock::release_block(block); 1895 } 1896 1897 if (free_handle_block() != NULL) { 1898 JNIHandleBlock* block = free_handle_block(); 1899 set_free_handle_block(NULL); 1900 JNIHandleBlock::release_block(block); 1901 } 1902 1903 // These have to be removed while this is still a valid thread. 1904 remove_stack_guard_pages(); 1905 1906 if (UseTLAB) { 1907 tlab().make_parsable(true); // retire TLAB 1908 } 1909 1910 if (JvmtiEnv::environments_might_exist()) { 1911 JvmtiExport::cleanup_thread(this); 1912 } 1913 1914 // We must flush any deferred card marks before removing a thread from 1915 // the list of active threads. 1916 Universe::heap()->flush_deferred_store_barrier(this); 1917 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1918 1919 #if INCLUDE_ALL_GCS 1920 // We must flush the G1-related buffers before removing a thread 1921 // from the list of active threads. We must do this after any deferred 1922 // card marks have been flushed (above) so that any entries that are 1923 // added to the thread's dirty card queue as a result are not lost. 1924 if (UseG1GC) { 1925 flush_barrier_queues(); 1926 } 1927 #endif // INCLUDE_ALL_GCS 1928 1929 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1930 Threads::remove(this); 1931 } 1932 1933 #if INCLUDE_ALL_GCS 1934 // Flush G1-related queues. 1935 void JavaThread::flush_barrier_queues() { 1936 satb_mark_queue().flush(); 1937 dirty_card_queue().flush(); 1938 } 1939 1940 void JavaThread::initialize_queues() { 1941 assert(!SafepointSynchronize::is_at_safepoint(), 1942 "we should not be at a safepoint"); 1943 1944 ObjPtrQueue& satb_queue = satb_mark_queue(); 1945 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1946 // The SATB queue should have been constructed with its active 1947 // field set to false. 1948 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1949 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1950 // If we are creating the thread during a marking cycle, we should 1951 // set the active field of the SATB queue to true. 1952 if (satb_queue_set.is_active()) { 1953 satb_queue.set_active(true); 1954 } 1955 1956 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1957 // The dirty card queue should have been constructed with its 1958 // active field set to true. 1959 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1960 } 1961 #endif // INCLUDE_ALL_GCS 1962 1963 void JavaThread::cleanup_failed_attach_current_thread() { 1964 if (get_thread_profiler() != NULL) { 1965 get_thread_profiler()->disengage(); 1966 ResourceMark rm; 1967 get_thread_profiler()->print(get_thread_name()); 1968 } 1969 1970 if (active_handles() != NULL) { 1971 JNIHandleBlock* block = active_handles(); 1972 set_active_handles(NULL); 1973 JNIHandleBlock::release_block(block); 1974 } 1975 1976 if (free_handle_block() != NULL) { 1977 JNIHandleBlock* block = free_handle_block(); 1978 set_free_handle_block(NULL); 1979 JNIHandleBlock::release_block(block); 1980 } 1981 1982 // These have to be removed while this is still a valid thread. 1983 remove_stack_guard_pages(); 1984 1985 if (UseTLAB) { 1986 tlab().make_parsable(true); // retire TLAB, if any 1987 } 1988 1989 #if INCLUDE_ALL_GCS 1990 if (UseG1GC) { 1991 flush_barrier_queues(); 1992 } 1993 #endif // INCLUDE_ALL_GCS 1994 1995 Threads::remove(this); 1996 delete this; 1997 } 1998 1999 2000 2001 2002 JavaThread* JavaThread::active() { 2003 Thread* thread = ThreadLocalStorage::thread(); 2004 assert(thread != NULL, "just checking"); 2005 if (thread->is_Java_thread()) { 2006 return (JavaThread*) thread; 2007 } else { 2008 assert(thread->is_VM_thread(), "this must be a vm thread"); 2009 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2010 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2011 assert(ret->is_Java_thread(), "must be a Java thread"); 2012 return ret; 2013 } 2014 } 2015 2016 bool JavaThread::is_lock_owned(address adr) const { 2017 if (Thread::is_lock_owned(adr)) return true; 2018 2019 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2020 if (chunk->contains(adr)) return true; 2021 } 2022 2023 return false; 2024 } 2025 2026 2027 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2028 chunk->set_next(monitor_chunks()); 2029 set_monitor_chunks(chunk); 2030 } 2031 2032 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2033 guarantee(monitor_chunks() != NULL, "must be non empty"); 2034 if (monitor_chunks() == chunk) { 2035 set_monitor_chunks(chunk->next()); 2036 } else { 2037 MonitorChunk* prev = monitor_chunks(); 2038 while (prev->next() != chunk) prev = prev->next(); 2039 prev->set_next(chunk->next()); 2040 } 2041 } 2042 2043 // JVM support. 2044 2045 // Note: this function shouldn't block if it's called in 2046 // _thread_in_native_trans state (such as from 2047 // check_special_condition_for_native_trans()). 2048 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2049 2050 if (has_last_Java_frame() && has_async_condition()) { 2051 // If we are at a polling page safepoint (not a poll return) 2052 // then we must defer async exception because live registers 2053 // will be clobbered by the exception path. Poll return is 2054 // ok because the call we a returning from already collides 2055 // with exception handling registers and so there is no issue. 2056 // (The exception handling path kills call result registers but 2057 // this is ok since the exception kills the result anyway). 2058 2059 if (is_at_poll_safepoint()) { 2060 // if the code we are returning to has deoptimized we must defer 2061 // the exception otherwise live registers get clobbered on the 2062 // exception path before deoptimization is able to retrieve them. 2063 // 2064 RegisterMap map(this, false); 2065 frame caller_fr = last_frame().sender(&map); 2066 assert(caller_fr.is_compiled_frame(), "what?"); 2067 if (caller_fr.is_deoptimized_frame()) { 2068 if (TraceExceptions) { 2069 ResourceMark rm; 2070 tty->print_cr("deferred async exception at compiled safepoint"); 2071 } 2072 return; 2073 } 2074 } 2075 } 2076 2077 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2078 if (condition == _no_async_condition) { 2079 // Conditions have changed since has_special_runtime_exit_condition() 2080 // was called: 2081 // - if we were here only because of an external suspend request, 2082 // then that was taken care of above (or cancelled) so we are done 2083 // - if we were here because of another async request, then it has 2084 // been cleared between the has_special_runtime_exit_condition() 2085 // and now so again we are done 2086 return; 2087 } 2088 2089 // Check for pending async. exception 2090 if (_pending_async_exception != NULL) { 2091 // Only overwrite an already pending exception, if it is not a threadDeath. 2092 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2093 2094 // We cannot call Exceptions::_throw(...) here because we cannot block 2095 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2096 2097 if (TraceExceptions) { 2098 ResourceMark rm; 2099 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); 2100 if (has_last_Java_frame()) { 2101 frame f = last_frame(); 2102 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); 2103 } 2104 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2105 } 2106 _pending_async_exception = NULL; 2107 clear_has_async_exception(); 2108 } 2109 } 2110 2111 if (check_unsafe_error && 2112 condition == _async_unsafe_access_error && !has_pending_exception()) { 2113 condition = _no_async_condition; // done 2114 switch (thread_state()) { 2115 case _thread_in_vm: { 2116 JavaThread* THREAD = this; 2117 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2118 } 2119 case _thread_in_native: { 2120 ThreadInVMfromNative tiv(this); 2121 JavaThread* THREAD = this; 2122 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2123 } 2124 case _thread_in_Java: { 2125 ThreadInVMfromJava tiv(this); 2126 JavaThread* THREAD = this; 2127 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2128 } 2129 default: 2130 ShouldNotReachHere(); 2131 } 2132 } 2133 2134 assert(condition == _no_async_condition || has_pending_exception() || 2135 (!check_unsafe_error && condition == _async_unsafe_access_error), 2136 "must have handled the async condition, if no exception"); 2137 } 2138 2139 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2140 // 2141 // Check for pending external suspend. Internal suspend requests do 2142 // not use handle_special_runtime_exit_condition(). 2143 // If JNIEnv proxies are allowed, don't self-suspend if the target 2144 // thread is not the current thread. In older versions of jdbx, jdbx 2145 // threads could call into the VM with another thread's JNIEnv so we 2146 // can be here operating on behalf of a suspended thread (4432884). 2147 bool do_self_suspend = is_external_suspend_with_lock(); 2148 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2149 // 2150 // Because thread is external suspended the safepoint code will count 2151 // thread as at a safepoint. This can be odd because we can be here 2152 // as _thread_in_Java which would normally transition to _thread_blocked 2153 // at a safepoint. We would like to mark the thread as _thread_blocked 2154 // before calling java_suspend_self like all other callers of it but 2155 // we must then observe proper safepoint protocol. (We can't leave 2156 // _thread_blocked with a safepoint in progress). However we can be 2157 // here as _thread_in_native_trans so we can't use a normal transition 2158 // constructor/destructor pair because they assert on that type of 2159 // transition. We could do something like: 2160 // 2161 // JavaThreadState state = thread_state(); 2162 // set_thread_state(_thread_in_vm); 2163 // { 2164 // ThreadBlockInVM tbivm(this); 2165 // java_suspend_self() 2166 // } 2167 // set_thread_state(_thread_in_vm_trans); 2168 // if (safepoint) block; 2169 // set_thread_state(state); 2170 // 2171 // but that is pretty messy. Instead we just go with the way the 2172 // code has worked before and note that this is the only path to 2173 // java_suspend_self that doesn't put the thread in _thread_blocked 2174 // mode. 2175 2176 frame_anchor()->make_walkable(this); 2177 java_suspend_self(); 2178 2179 // We might be here for reasons in addition to the self-suspend request 2180 // so check for other async requests. 2181 } 2182 2183 if (check_asyncs) { 2184 check_and_handle_async_exceptions(); 2185 } 2186 } 2187 2188 void JavaThread::send_thread_stop(oop java_throwable) { 2189 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2190 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2191 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2192 2193 // Do not throw asynchronous exceptions against the compiler thread 2194 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2195 if (!can_call_java()) return; 2196 2197 { 2198 // Actually throw the Throwable against the target Thread - however 2199 // only if there is no thread death exception installed already. 2200 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2201 // If the topmost frame is a runtime stub, then we are calling into 2202 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2203 // must deoptimize the caller before continuing, as the compiled exception handler table 2204 // may not be valid 2205 if (has_last_Java_frame()) { 2206 frame f = last_frame(); 2207 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2208 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2209 RegisterMap reg_map(this, UseBiasedLocking); 2210 frame compiled_frame = f.sender(®_map); 2211 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2212 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2213 } 2214 } 2215 } 2216 2217 // Set async. pending exception in thread. 2218 set_pending_async_exception(java_throwable); 2219 2220 if (TraceExceptions) { 2221 ResourceMark rm; 2222 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2223 } 2224 // for AbortVMOnException flag 2225 Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2226 } 2227 } 2228 2229 2230 // Interrupt thread so it will wake up from a potential wait() 2231 Thread::interrupt(this); 2232 } 2233 2234 // External suspension mechanism. 2235 // 2236 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2237 // to any VM_locks and it is at a transition 2238 // Self-suspension will happen on the transition out of the vm. 2239 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2240 // 2241 // Guarantees on return: 2242 // + Target thread will not execute any new bytecode (that's why we need to 2243 // force a safepoint) 2244 // + Target thread will not enter any new monitors 2245 // 2246 void JavaThread::java_suspend() { 2247 { MutexLocker mu(Threads_lock); 2248 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2249 return; 2250 } 2251 } 2252 2253 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2254 if (!is_external_suspend()) { 2255 // a racing resume has cancelled us; bail out now 2256 return; 2257 } 2258 2259 // suspend is done 2260 uint32_t debug_bits = 0; 2261 // Warning: is_ext_suspend_completed() may temporarily drop the 2262 // SR_lock to allow the thread to reach a stable thread state if 2263 // it is currently in a transient thread state. 2264 if (is_ext_suspend_completed(false /* !called_by_wait */, 2265 SuspendRetryDelay, &debug_bits)) { 2266 return; 2267 } 2268 } 2269 2270 VM_ForceSafepoint vm_suspend; 2271 VMThread::execute(&vm_suspend); 2272 } 2273 2274 // Part II of external suspension. 2275 // A JavaThread self suspends when it detects a pending external suspend 2276 // request. This is usually on transitions. It is also done in places 2277 // where continuing to the next transition would surprise the caller, 2278 // e.g., monitor entry. 2279 // 2280 // Returns the number of times that the thread self-suspended. 2281 // 2282 // Note: DO NOT call java_suspend_self() when you just want to block current 2283 // thread. java_suspend_self() is the second stage of cooperative 2284 // suspension for external suspend requests and should only be used 2285 // to complete an external suspend request. 2286 // 2287 int JavaThread::java_suspend_self() { 2288 int ret = 0; 2289 2290 // we are in the process of exiting so don't suspend 2291 if (is_exiting()) { 2292 clear_external_suspend(); 2293 return ret; 2294 } 2295 2296 assert(_anchor.walkable() || 2297 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2298 "must have walkable stack"); 2299 2300 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2301 2302 assert(!this->is_ext_suspended(), 2303 "a thread trying to self-suspend should not already be suspended"); 2304 2305 if (this->is_suspend_equivalent()) { 2306 // If we are self-suspending as a result of the lifting of a 2307 // suspend equivalent condition, then the suspend_equivalent 2308 // flag is not cleared until we set the ext_suspended flag so 2309 // that wait_for_ext_suspend_completion() returns consistent 2310 // results. 2311 this->clear_suspend_equivalent(); 2312 } 2313 2314 // A racing resume may have cancelled us before we grabbed SR_lock 2315 // above. Or another external suspend request could be waiting for us 2316 // by the time we return from SR_lock()->wait(). The thread 2317 // that requested the suspension may already be trying to walk our 2318 // stack and if we return now, we can change the stack out from under 2319 // it. This would be a "bad thing (TM)" and cause the stack walker 2320 // to crash. We stay self-suspended until there are no more pending 2321 // external suspend requests. 2322 while (is_external_suspend()) { 2323 ret++; 2324 this->set_ext_suspended(); 2325 2326 // _ext_suspended flag is cleared by java_resume() 2327 while (is_ext_suspended()) { 2328 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2329 } 2330 } 2331 2332 return ret; 2333 } 2334 2335 #ifdef ASSERT 2336 // verify the JavaThread has not yet been published in the Threads::list, and 2337 // hence doesn't need protection from concurrent access at this stage 2338 void JavaThread::verify_not_published() { 2339 if (!Threads_lock->owned_by_self()) { 2340 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2341 assert(!Threads::includes(this), 2342 "java thread shouldn't have been published yet!"); 2343 } else { 2344 assert(!Threads::includes(this), 2345 "java thread shouldn't have been published yet!"); 2346 } 2347 } 2348 #endif 2349 2350 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2351 // progress or when _suspend_flags is non-zero. 2352 // Current thread needs to self-suspend if there is a suspend request and/or 2353 // block if a safepoint is in progress. 2354 // Async exception ISN'T checked. 2355 // Note only the ThreadInVMfromNative transition can call this function 2356 // directly and when thread state is _thread_in_native_trans 2357 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2358 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2359 2360 JavaThread *curJT = JavaThread::current(); 2361 bool do_self_suspend = thread->is_external_suspend(); 2362 2363 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2364 2365 // If JNIEnv proxies are allowed, don't self-suspend if the target 2366 // thread is not the current thread. In older versions of jdbx, jdbx 2367 // threads could call into the VM with another thread's JNIEnv so we 2368 // can be here operating on behalf of a suspended thread (4432884). 2369 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2370 JavaThreadState state = thread->thread_state(); 2371 2372 // We mark this thread_blocked state as a suspend-equivalent so 2373 // that a caller to is_ext_suspend_completed() won't be confused. 2374 // The suspend-equivalent state is cleared by java_suspend_self(). 2375 thread->set_suspend_equivalent(); 2376 2377 // If the safepoint code sees the _thread_in_native_trans state, it will 2378 // wait until the thread changes to other thread state. There is no 2379 // guarantee on how soon we can obtain the SR_lock and complete the 2380 // self-suspend request. It would be a bad idea to let safepoint wait for 2381 // too long. Temporarily change the state to _thread_blocked to 2382 // let the VM thread know that this thread is ready for GC. The problem 2383 // of changing thread state is that safepoint could happen just after 2384 // java_suspend_self() returns after being resumed, and VM thread will 2385 // see the _thread_blocked state. We must check for safepoint 2386 // after restoring the state and make sure we won't leave while a safepoint 2387 // is in progress. 2388 thread->set_thread_state(_thread_blocked); 2389 thread->java_suspend_self(); 2390 thread->set_thread_state(state); 2391 // Make sure new state is seen by VM thread 2392 if (os::is_MP()) { 2393 if (UseMembar) { 2394 // Force a fence between the write above and read below 2395 OrderAccess::fence(); 2396 } else { 2397 // Must use this rather than serialization page in particular on Windows 2398 InterfaceSupport::serialize_memory(thread); 2399 } 2400 } 2401 } 2402 2403 if (SafepointSynchronize::do_call_back()) { 2404 // If we are safepointing, then block the caller which may not be 2405 // the same as the target thread (see above). 2406 SafepointSynchronize::block(curJT); 2407 } 2408 2409 if (thread->is_deopt_suspend()) { 2410 thread->clear_deopt_suspend(); 2411 RegisterMap map(thread, false); 2412 frame f = thread->last_frame(); 2413 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2414 f = f.sender(&map); 2415 } 2416 if (f.id() == thread->must_deopt_id()) { 2417 thread->clear_must_deopt_id(); 2418 f.deoptimize(thread); 2419 } else { 2420 fatal("missed deoptimization!"); 2421 } 2422 } 2423 } 2424 2425 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2426 // progress or when _suspend_flags is non-zero. 2427 // Current thread needs to self-suspend if there is a suspend request and/or 2428 // block if a safepoint is in progress. 2429 // Also check for pending async exception (not including unsafe access error). 2430 // Note only the native==>VM/Java barriers can call this function and when 2431 // thread state is _thread_in_native_trans. 2432 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2433 check_safepoint_and_suspend_for_native_trans(thread); 2434 2435 if (thread->has_async_exception()) { 2436 // We are in _thread_in_native_trans state, don't handle unsafe 2437 // access error since that may block. 2438 thread->check_and_handle_async_exceptions(false); 2439 } 2440 } 2441 2442 // This is a variant of the normal 2443 // check_special_condition_for_native_trans with slightly different 2444 // semantics for use by critical native wrappers. It does all the 2445 // normal checks but also performs the transition back into 2446 // thread_in_Java state. This is required so that critical natives 2447 // can potentially block and perform a GC if they are the last thread 2448 // exiting the GC_locker. 2449 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2450 check_special_condition_for_native_trans(thread); 2451 2452 // Finish the transition 2453 thread->set_thread_state(_thread_in_Java); 2454 2455 if (thread->do_critical_native_unlock()) { 2456 ThreadInVMfromJavaNoAsyncException tiv(thread); 2457 GC_locker::unlock_critical(thread); 2458 thread->clear_critical_native_unlock(); 2459 } 2460 } 2461 2462 // We need to guarantee the Threads_lock here, since resumes are not 2463 // allowed during safepoint synchronization 2464 // Can only resume from an external suspension 2465 void JavaThread::java_resume() { 2466 assert_locked_or_safepoint(Threads_lock); 2467 2468 // Sanity check: thread is gone, has started exiting or the thread 2469 // was not externally suspended. 2470 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2471 return; 2472 } 2473 2474 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2475 2476 clear_external_suspend(); 2477 2478 if (is_ext_suspended()) { 2479 clear_ext_suspended(); 2480 SR_lock()->notify_all(); 2481 } 2482 } 2483 2484 void JavaThread::create_stack_guard_pages() { 2485 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2486 address low_addr = stack_base() - stack_size(); 2487 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2488 2489 int allocate = os::allocate_stack_guard_pages(); 2490 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2491 2492 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2493 warning("Attempt to allocate stack guard pages failed."); 2494 return; 2495 } 2496 2497 if (os::guard_memory((char *) low_addr, len)) { 2498 _stack_guard_state = stack_guard_enabled; 2499 } else { 2500 warning("Attempt to protect stack guard pages failed."); 2501 if (os::uncommit_memory((char *) low_addr, len)) { 2502 warning("Attempt to deallocate stack guard pages failed."); 2503 } 2504 } 2505 } 2506 2507 void JavaThread::remove_stack_guard_pages() { 2508 assert(Thread::current() == this, "from different thread"); 2509 if (_stack_guard_state == stack_guard_unused) return; 2510 address low_addr = stack_base() - stack_size(); 2511 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2512 2513 if (os::allocate_stack_guard_pages()) { 2514 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2515 _stack_guard_state = stack_guard_unused; 2516 } else { 2517 warning("Attempt to deallocate stack guard pages failed."); 2518 } 2519 } else { 2520 if (_stack_guard_state == stack_guard_unused) return; 2521 if (os::unguard_memory((char *) low_addr, len)) { 2522 _stack_guard_state = stack_guard_unused; 2523 } else { 2524 warning("Attempt to unprotect stack guard pages failed."); 2525 } 2526 } 2527 } 2528 2529 void JavaThread::enable_stack_yellow_zone() { 2530 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2531 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2532 2533 // The base notation is from the stacks point of view, growing downward. 2534 // We need to adjust it to work correctly with guard_memory() 2535 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2536 2537 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2538 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2539 2540 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2541 _stack_guard_state = stack_guard_enabled; 2542 } else { 2543 warning("Attempt to guard stack yellow zone failed."); 2544 } 2545 enable_register_stack_guard(); 2546 } 2547 2548 void JavaThread::disable_stack_yellow_zone() { 2549 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2550 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2551 2552 // Simply return if called for a thread that does not use guard pages. 2553 if (_stack_guard_state == stack_guard_unused) return; 2554 2555 // The base notation is from the stacks point of view, growing downward. 2556 // We need to adjust it to work correctly with guard_memory() 2557 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2558 2559 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2560 _stack_guard_state = stack_guard_yellow_disabled; 2561 } else { 2562 warning("Attempt to unguard stack yellow zone failed."); 2563 } 2564 disable_register_stack_guard(); 2565 } 2566 2567 void JavaThread::enable_stack_red_zone() { 2568 // The base notation is from the stacks point of view, growing downward. 2569 // We need to adjust it to work correctly with guard_memory() 2570 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2571 address base = stack_red_zone_base() - stack_red_zone_size(); 2572 2573 guarantee(base < stack_base(), "Error calculating stack red zone"); 2574 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2575 2576 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2577 warning("Attempt to guard stack red zone failed."); 2578 } 2579 } 2580 2581 void JavaThread::disable_stack_red_zone() { 2582 // The base notation is from the stacks point of view, growing downward. 2583 // We need to adjust it to work correctly with guard_memory() 2584 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2585 address base = stack_red_zone_base() - stack_red_zone_size(); 2586 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2587 warning("Attempt to unguard stack red zone failed."); 2588 } 2589 } 2590 2591 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2592 // ignore is there is no stack 2593 if (!has_last_Java_frame()) return; 2594 // traverse the stack frames. Starts from top frame. 2595 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2596 frame* fr = fst.current(); 2597 f(fr, fst.register_map()); 2598 } 2599 } 2600 2601 2602 #ifndef PRODUCT 2603 // Deoptimization 2604 // Function for testing deoptimization 2605 void JavaThread::deoptimize() { 2606 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2607 StackFrameStream fst(this, UseBiasedLocking); 2608 bool deopt = false; // Dump stack only if a deopt actually happens. 2609 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2610 // Iterate over all frames in the thread and deoptimize 2611 for (; !fst.is_done(); fst.next()) { 2612 if (fst.current()->can_be_deoptimized()) { 2613 2614 if (only_at) { 2615 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2616 // consists of comma or carriage return separated numbers so 2617 // search for the current bci in that string. 2618 address pc = fst.current()->pc(); 2619 nmethod* nm = (nmethod*) fst.current()->cb(); 2620 ScopeDesc* sd = nm->scope_desc_at(pc); 2621 char buffer[8]; 2622 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2623 size_t len = strlen(buffer); 2624 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2625 while (found != NULL) { 2626 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2627 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2628 // Check that the bci found is bracketed by terminators. 2629 break; 2630 } 2631 found = strstr(found + 1, buffer); 2632 } 2633 if (!found) { 2634 continue; 2635 } 2636 } 2637 2638 if (DebugDeoptimization && !deopt) { 2639 deopt = true; // One-time only print before deopt 2640 tty->print_cr("[BEFORE Deoptimization]"); 2641 trace_frames(); 2642 trace_stack(); 2643 } 2644 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2645 } 2646 } 2647 2648 if (DebugDeoptimization && deopt) { 2649 tty->print_cr("[AFTER Deoptimization]"); 2650 trace_frames(); 2651 } 2652 } 2653 2654 2655 // Make zombies 2656 void JavaThread::make_zombies() { 2657 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2658 if (fst.current()->can_be_deoptimized()) { 2659 // it is a Java nmethod 2660 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2661 nm->make_not_entrant(); 2662 } 2663 } 2664 } 2665 #endif // PRODUCT 2666 2667 2668 void JavaThread::deoptimized_wrt_marked_nmethods() { 2669 if (!has_last_Java_frame()) return; 2670 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2671 StackFrameStream fst(this, UseBiasedLocking); 2672 for (; !fst.is_done(); fst.next()) { 2673 if (fst.current()->should_be_deoptimized()) { 2674 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2675 } 2676 } 2677 } 2678 2679 2680 // If the caller is a NamedThread, then remember, in the current scope, 2681 // the given JavaThread in its _processed_thread field. 2682 class RememberProcessedThread: public StackObj { 2683 NamedThread* _cur_thr; 2684 public: 2685 RememberProcessedThread(JavaThread* jthr) { 2686 Thread* thread = Thread::current(); 2687 if (thread->is_Named_thread()) { 2688 _cur_thr = (NamedThread *)thread; 2689 _cur_thr->set_processed_thread(jthr); 2690 } else { 2691 _cur_thr = NULL; 2692 } 2693 } 2694 2695 ~RememberProcessedThread() { 2696 if (_cur_thr) { 2697 _cur_thr->set_processed_thread(NULL); 2698 } 2699 } 2700 }; 2701 2702 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2703 // Verify that the deferred card marks have been flushed. 2704 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2705 2706 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2707 // since there may be more than one thread using each ThreadProfiler. 2708 2709 // Traverse the GCHandles 2710 Thread::oops_do(f, cld_f, cf); 2711 2712 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);) 2713 2714 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2715 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2716 2717 if (has_last_Java_frame()) { 2718 // Record JavaThread to GC thread 2719 RememberProcessedThread rpt(this); 2720 2721 // Traverse the privileged stack 2722 if (_privileged_stack_top != NULL) { 2723 _privileged_stack_top->oops_do(f); 2724 } 2725 2726 // traverse the registered growable array 2727 if (_array_for_gc != NULL) { 2728 for (int index = 0; index < _array_for_gc->length(); index++) { 2729 f->do_oop(_array_for_gc->adr_at(index)); 2730 } 2731 } 2732 2733 // Traverse the monitor chunks 2734 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2735 chunk->oops_do(f); 2736 } 2737 2738 // Traverse the execution stack 2739 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2740 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2741 } 2742 } 2743 2744 // callee_target is never live across a gc point so NULL it here should 2745 // it still contain a methdOop. 2746 2747 set_callee_target(NULL); 2748 2749 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2750 // If we have deferred set_locals there might be oops waiting to be 2751 // written 2752 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2753 if (list != NULL) { 2754 for (int i = 0; i < list->length(); i++) { 2755 list->at(i)->oops_do(f); 2756 } 2757 } 2758 2759 // Traverse instance variables at the end since the GC may be moving things 2760 // around using this function 2761 f->do_oop((oop*) &_threadObj); 2762 f->do_oop((oop*) &_vm_result); 2763 f->do_oop((oop*) &_exception_oop); 2764 f->do_oop((oop*) &_pending_async_exception); 2765 2766 if (jvmti_thread_state() != NULL) { 2767 jvmti_thread_state()->oops_do(f); 2768 } 2769 } 2770 2771 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2772 Thread::nmethods_do(cf); // (super method is a no-op) 2773 2774 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2775 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2776 2777 if (has_last_Java_frame()) { 2778 // Traverse the execution stack 2779 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2780 fst.current()->nmethods_do(cf); 2781 } 2782 } 2783 } 2784 2785 void JavaThread::metadata_do(void f(Metadata*)) { 2786 if (has_last_Java_frame()) { 2787 // Traverse the execution stack to call f() on the methods in the stack 2788 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2789 fst.current()->metadata_do(f); 2790 } 2791 } else if (is_Compiler_thread()) { 2792 // need to walk ciMetadata in current compile tasks to keep alive. 2793 CompilerThread* ct = (CompilerThread*)this; 2794 if (ct->env() != NULL) { 2795 ct->env()->metadata_do(f); 2796 } 2797 if (ct->task() != NULL) { 2798 ct->task()->metadata_do(f); 2799 } 2800 } 2801 } 2802 2803 // Printing 2804 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2805 switch (_thread_state) { 2806 case _thread_uninitialized: return "_thread_uninitialized"; 2807 case _thread_new: return "_thread_new"; 2808 case _thread_new_trans: return "_thread_new_trans"; 2809 case _thread_in_native: return "_thread_in_native"; 2810 case _thread_in_native_trans: return "_thread_in_native_trans"; 2811 case _thread_in_vm: return "_thread_in_vm"; 2812 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2813 case _thread_in_Java: return "_thread_in_Java"; 2814 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2815 case _thread_blocked: return "_thread_blocked"; 2816 case _thread_blocked_trans: return "_thread_blocked_trans"; 2817 default: return "unknown thread state"; 2818 } 2819 } 2820 2821 #ifndef PRODUCT 2822 void JavaThread::print_thread_state_on(outputStream *st) const { 2823 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2824 }; 2825 void JavaThread::print_thread_state() const { 2826 print_thread_state_on(tty); 2827 } 2828 #endif // PRODUCT 2829 2830 // Called by Threads::print() for VM_PrintThreads operation 2831 void JavaThread::print_on(outputStream *st) const { 2832 st->print("\"%s\" ", get_thread_name()); 2833 oop thread_oop = threadObj(); 2834 if (thread_oop != NULL) { 2835 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2836 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2837 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2838 } 2839 Thread::print_on(st); 2840 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2841 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2842 if (thread_oop != NULL) { 2843 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2844 } 2845 #ifndef PRODUCT 2846 print_thread_state_on(st); 2847 _safepoint_state->print_on(st); 2848 #endif // PRODUCT 2849 } 2850 2851 // Called by fatal error handler. The difference between this and 2852 // JavaThread::print() is that we can't grab lock or allocate memory. 2853 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2854 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2855 oop thread_obj = threadObj(); 2856 if (thread_obj != NULL) { 2857 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2858 } 2859 st->print(" ["); 2860 st->print("%s", _get_thread_state_name(_thread_state)); 2861 if (osthread()) { 2862 st->print(", id=%d", osthread()->thread_id()); 2863 } 2864 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2865 p2i(_stack_base - _stack_size), p2i(_stack_base)); 2866 st->print("]"); 2867 return; 2868 } 2869 2870 // Verification 2871 2872 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2873 2874 void JavaThread::verify() { 2875 // Verify oops in the thread. 2876 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2877 2878 // Verify the stack frames. 2879 frames_do(frame_verify); 2880 } 2881 2882 // CR 6300358 (sub-CR 2137150) 2883 // Most callers of this method assume that it can't return NULL but a 2884 // thread may not have a name whilst it is in the process of attaching to 2885 // the VM - see CR 6412693, and there are places where a JavaThread can be 2886 // seen prior to having it's threadObj set (eg JNI attaching threads and 2887 // if vm exit occurs during initialization). These cases can all be accounted 2888 // for such that this method never returns NULL. 2889 const char* JavaThread::get_thread_name() const { 2890 #ifdef ASSERT 2891 // early safepoints can hit while current thread does not yet have TLS 2892 if (!SafepointSynchronize::is_at_safepoint()) { 2893 Thread *cur = Thread::current(); 2894 if (!(cur->is_Java_thread() && cur == this)) { 2895 // Current JavaThreads are allowed to get their own name without 2896 // the Threads_lock. 2897 assert_locked_or_safepoint(Threads_lock); 2898 } 2899 } 2900 #endif // ASSERT 2901 return get_thread_name_string(); 2902 } 2903 2904 // Returns a non-NULL representation of this thread's name, or a suitable 2905 // descriptive string if there is no set name 2906 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2907 const char* name_str; 2908 oop thread_obj = threadObj(); 2909 if (thread_obj != NULL) { 2910 oop name = java_lang_Thread::name(thread_obj); 2911 if (name != NULL) { 2912 if (buf == NULL) { 2913 name_str = java_lang_String::as_utf8_string(name); 2914 } else { 2915 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 2916 } 2917 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2918 name_str = "<no-name - thread is attaching>"; 2919 } else { 2920 name_str = Thread::name(); 2921 } 2922 } else { 2923 name_str = Thread::name(); 2924 } 2925 assert(name_str != NULL, "unexpected NULL thread name"); 2926 return name_str; 2927 } 2928 2929 2930 const char* JavaThread::get_threadgroup_name() const { 2931 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2932 oop thread_obj = threadObj(); 2933 if (thread_obj != NULL) { 2934 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2935 if (thread_group != NULL) { 2936 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2937 // ThreadGroup.name can be null 2938 if (name != NULL) { 2939 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2940 return str; 2941 } 2942 } 2943 } 2944 return NULL; 2945 } 2946 2947 const char* JavaThread::get_parent_name() const { 2948 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2949 oop thread_obj = threadObj(); 2950 if (thread_obj != NULL) { 2951 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2952 if (thread_group != NULL) { 2953 oop parent = java_lang_ThreadGroup::parent(thread_group); 2954 if (parent != NULL) { 2955 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2956 // ThreadGroup.name can be null 2957 if (name != NULL) { 2958 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2959 return str; 2960 } 2961 } 2962 } 2963 } 2964 return NULL; 2965 } 2966 2967 ThreadPriority JavaThread::java_priority() const { 2968 oop thr_oop = threadObj(); 2969 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2970 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2971 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2972 return priority; 2973 } 2974 2975 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2976 2977 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2978 // Link Java Thread object <-> C++ Thread 2979 2980 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2981 // and put it into a new Handle. The Handle "thread_oop" can then 2982 // be used to pass the C++ thread object to other methods. 2983 2984 // Set the Java level thread object (jthread) field of the 2985 // new thread (a JavaThread *) to C++ thread object using the 2986 // "thread_oop" handle. 2987 2988 // Set the thread field (a JavaThread *) of the 2989 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2990 2991 Handle thread_oop(Thread::current(), 2992 JNIHandles::resolve_non_null(jni_thread)); 2993 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 2994 "must be initialized"); 2995 set_threadObj(thread_oop()); 2996 java_lang_Thread::set_thread(thread_oop(), this); 2997 2998 if (prio == NoPriority) { 2999 prio = java_lang_Thread::priority(thread_oop()); 3000 assert(prio != NoPriority, "A valid priority should be present"); 3001 } 3002 3003 // Push the Java priority down to the native thread; needs Threads_lock 3004 Thread::set_priority(this, prio); 3005 3006 prepare_ext(); 3007 3008 // Add the new thread to the Threads list and set it in motion. 3009 // We must have threads lock in order to call Threads::add. 3010 // It is crucial that we do not block before the thread is 3011 // added to the Threads list for if a GC happens, then the java_thread oop 3012 // will not be visited by GC. 3013 Threads::add(this); 3014 } 3015 3016 oop JavaThread::current_park_blocker() { 3017 // Support for JSR-166 locks 3018 oop thread_oop = threadObj(); 3019 if (thread_oop != NULL && 3020 JDK_Version::current().supports_thread_park_blocker()) { 3021 return java_lang_Thread::park_blocker(thread_oop); 3022 } 3023 return NULL; 3024 } 3025 3026 3027 void JavaThread::print_stack_on(outputStream* st) { 3028 if (!has_last_Java_frame()) return; 3029 ResourceMark rm; 3030 HandleMark hm; 3031 3032 RegisterMap reg_map(this); 3033 vframe* start_vf = last_java_vframe(®_map); 3034 int count = 0; 3035 for (vframe* f = start_vf; f; f = f->sender()) { 3036 if (f->is_java_frame()) { 3037 javaVFrame* jvf = javaVFrame::cast(f); 3038 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3039 3040 // Print out lock information 3041 if (JavaMonitorsInStackTrace) { 3042 jvf->print_lock_info_on(st, count); 3043 } 3044 } else { 3045 // Ignore non-Java frames 3046 } 3047 3048 // Bail-out case for too deep stacks 3049 count++; 3050 if (MaxJavaStackTraceDepth == count) return; 3051 } 3052 } 3053 3054 3055 // JVMTI PopFrame support 3056 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3057 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3058 if (in_bytes(size_in_bytes) != 0) { 3059 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3060 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3061 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3062 } 3063 } 3064 3065 void* JavaThread::popframe_preserved_args() { 3066 return _popframe_preserved_args; 3067 } 3068 3069 ByteSize JavaThread::popframe_preserved_args_size() { 3070 return in_ByteSize(_popframe_preserved_args_size); 3071 } 3072 3073 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3074 int sz = in_bytes(popframe_preserved_args_size()); 3075 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3076 return in_WordSize(sz / wordSize); 3077 } 3078 3079 void JavaThread::popframe_free_preserved_args() { 3080 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3081 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3082 _popframe_preserved_args = NULL; 3083 _popframe_preserved_args_size = 0; 3084 } 3085 3086 #ifndef PRODUCT 3087 3088 void JavaThread::trace_frames() { 3089 tty->print_cr("[Describe stack]"); 3090 int frame_no = 1; 3091 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3092 tty->print(" %d. ", frame_no++); 3093 fst.current()->print_value_on(tty, this); 3094 tty->cr(); 3095 } 3096 } 3097 3098 class PrintAndVerifyOopClosure: public OopClosure { 3099 protected: 3100 template <class T> inline void do_oop_work(T* p) { 3101 oop obj = oopDesc::load_decode_heap_oop(p); 3102 if (obj == NULL) return; 3103 tty->print(INTPTR_FORMAT ": ", p2i(p)); 3104 if (obj->is_oop_or_null()) { 3105 if (obj->is_objArray()) { 3106 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); 3107 } else { 3108 obj->print(); 3109 } 3110 } else { 3111 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); 3112 } 3113 tty->cr(); 3114 } 3115 public: 3116 virtual void do_oop(oop* p) { do_oop_work(p); } 3117 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3118 }; 3119 3120 3121 static void oops_print(frame* f, const RegisterMap *map) { 3122 PrintAndVerifyOopClosure print; 3123 f->print_value(); 3124 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3125 } 3126 3127 // Print our all the locations that contain oops and whether they are 3128 // valid or not. This useful when trying to find the oldest frame 3129 // where an oop has gone bad since the frame walk is from youngest to 3130 // oldest. 3131 void JavaThread::trace_oops() { 3132 tty->print_cr("[Trace oops]"); 3133 frames_do(oops_print); 3134 } 3135 3136 3137 #ifdef ASSERT 3138 // Print or validate the layout of stack frames 3139 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3140 ResourceMark rm; 3141 PRESERVE_EXCEPTION_MARK; 3142 FrameValues values; 3143 int frame_no = 0; 3144 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3145 fst.current()->describe(values, ++frame_no); 3146 if (depth == frame_no) break; 3147 } 3148 if (validate_only) { 3149 values.validate(); 3150 } else { 3151 tty->print_cr("[Describe stack layout]"); 3152 values.print(this); 3153 } 3154 } 3155 #endif 3156 3157 void JavaThread::trace_stack_from(vframe* start_vf) { 3158 ResourceMark rm; 3159 int vframe_no = 1; 3160 for (vframe* f = start_vf; f; f = f->sender()) { 3161 if (f->is_java_frame()) { 3162 javaVFrame::cast(f)->print_activation(vframe_no++); 3163 } else { 3164 f->print(); 3165 } 3166 if (vframe_no > StackPrintLimit) { 3167 tty->print_cr("...<more frames>..."); 3168 return; 3169 } 3170 } 3171 } 3172 3173 3174 void JavaThread::trace_stack() { 3175 if (!has_last_Java_frame()) return; 3176 ResourceMark rm; 3177 HandleMark hm; 3178 RegisterMap reg_map(this); 3179 trace_stack_from(last_java_vframe(®_map)); 3180 } 3181 3182 3183 #endif // PRODUCT 3184 3185 3186 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3187 assert(reg_map != NULL, "a map must be given"); 3188 frame f = last_frame(); 3189 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3190 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3191 } 3192 return NULL; 3193 } 3194 3195 3196 Klass* JavaThread::security_get_caller_class(int depth) { 3197 vframeStream vfst(this); 3198 vfst.security_get_caller_frame(depth); 3199 if (!vfst.at_end()) { 3200 return vfst.method()->method_holder(); 3201 } 3202 return NULL; 3203 } 3204 3205 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3206 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3207 CompileBroker::compiler_thread_loop(); 3208 } 3209 3210 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3211 NMethodSweeper::sweeper_loop(); 3212 } 3213 3214 // Create a CompilerThread 3215 CompilerThread::CompilerThread(CompileQueue* queue, 3216 CompilerCounters* counters) 3217 : JavaThread(&compiler_thread_entry) { 3218 _env = NULL; 3219 _log = NULL; 3220 _task = NULL; 3221 _queue = queue; 3222 _counters = counters; 3223 _buffer_blob = NULL; 3224 _compiler = NULL; 3225 3226 #ifndef PRODUCT 3227 _ideal_graph_printer = NULL; 3228 #endif 3229 } 3230 3231 bool CompilerThread::can_call_java() const { 3232 return _compiler != NULL && _compiler->is_jvmci(); 3233 } 3234 3235 // Create sweeper thread 3236 CodeCacheSweeperThread::CodeCacheSweeperThread() 3237 : JavaThread(&sweeper_thread_entry) { 3238 _scanned_nmethod = NULL; 3239 } 3240 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3241 JavaThread::oops_do(f, cld_f, cf); 3242 if (_scanned_nmethod != NULL && cf != NULL) { 3243 // Safepoints can occur when the sweeper is scanning an nmethod so 3244 // process it here to make sure it isn't unloaded in the middle of 3245 // a scan. 3246 cf->do_code_blob(_scanned_nmethod); 3247 } 3248 } 3249 3250 3251 // ======= Threads ======== 3252 3253 // The Threads class links together all active threads, and provides 3254 // operations over all threads. It is protected by its own Mutex 3255 // lock, which is also used in other contexts to protect thread 3256 // operations from having the thread being operated on from exiting 3257 // and going away unexpectedly (e.g., safepoint synchronization) 3258 3259 JavaThread* Threads::_thread_list = NULL; 3260 int Threads::_number_of_threads = 0; 3261 int Threads::_number_of_non_daemon_threads = 0; 3262 int Threads::_return_code = 0; 3263 int Threads::_thread_claim_parity = 0; 3264 size_t JavaThread::_stack_size_at_create = 0; 3265 #ifdef ASSERT 3266 bool Threads::_vm_complete = false; 3267 #endif 3268 3269 // All JavaThreads 3270 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3271 3272 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3273 void Threads::threads_do(ThreadClosure* tc) { 3274 assert_locked_or_safepoint(Threads_lock); 3275 // ALL_JAVA_THREADS iterates through all JavaThreads 3276 ALL_JAVA_THREADS(p) { 3277 tc->do_thread(p); 3278 } 3279 // Someday we could have a table or list of all non-JavaThreads. 3280 // For now, just manually iterate through them. 3281 tc->do_thread(VMThread::vm_thread()); 3282 Universe::heap()->gc_threads_do(tc); 3283 WatcherThread *wt = WatcherThread::watcher_thread(); 3284 // Strictly speaking, the following NULL check isn't sufficient to make sure 3285 // the data for WatcherThread is still valid upon being examined. However, 3286 // considering that WatchThread terminates when the VM is on the way to 3287 // exit at safepoint, the chance of the above is extremely small. The right 3288 // way to prevent termination of WatcherThread would be to acquire 3289 // Terminator_lock, but we can't do that without violating the lock rank 3290 // checking in some cases. 3291 if (wt != NULL) { 3292 tc->do_thread(wt); 3293 } 3294 3295 // If CompilerThreads ever become non-JavaThreads, add them here 3296 } 3297 3298 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3299 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3300 3301 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3302 create_vm_init_libraries(); 3303 } 3304 3305 initialize_class(vmSymbols::java_lang_String(), CHECK); 3306 3307 // Initialize java_lang.System (needed before creating the thread) 3308 initialize_class(vmSymbols::java_lang_System(), CHECK); 3309 // The VM creates & returns objects of this class. Make sure it's initialized. 3310 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3311 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3312 Handle thread_group = create_initial_thread_group(CHECK); 3313 Universe::set_main_thread_group(thread_group()); 3314 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3315 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3316 main_thread->set_threadObj(thread_object); 3317 // Set thread status to running since main thread has 3318 // been started and running. 3319 java_lang_Thread::set_thread_status(thread_object, 3320 java_lang_Thread::RUNNABLE); 3321 3322 // The VM preresolves methods to these classes. Make sure that they get initialized 3323 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3324 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3325 call_initializeSystemClass(CHECK); 3326 3327 // get the Java runtime name after java.lang.System is initialized 3328 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3329 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3330 3331 // an instance of OutOfMemory exception has been allocated earlier 3332 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3333 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3334 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3335 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3336 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3337 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3338 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3339 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3340 } 3341 3342 void Threads::initialize_jsr292_core_classes(TRAPS) { 3343 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3344 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3345 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3346 } 3347 3348 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3349 extern void JDK_Version_init(); 3350 3351 // Preinitialize version info. 3352 VM_Version::early_initialize(); 3353 3354 // Check version 3355 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3356 3357 // Initialize the output stream module 3358 ostream_init(); 3359 3360 // Process java launcher properties. 3361 Arguments::process_sun_java_launcher_properties(args); 3362 3363 // Initialize the os module before using TLS 3364 os::init(); 3365 3366 // Record VM creation timing statistics 3367 TraceVmCreationTime create_vm_timer; 3368 create_vm_timer.start(); 3369 3370 // Initialize system properties. 3371 Arguments::init_system_properties(); 3372 3373 // So that JDK version can be used as a discriminator when parsing arguments 3374 JDK_Version_init(); 3375 3376 // Update/Initialize System properties after JDK version number is known 3377 Arguments::init_version_specific_system_properties(); 3378 3379 // Make sure to initialize log configuration *before* parsing arguments 3380 LogConfiguration::initialize(create_vm_timer.begin_time()); 3381 3382 // Parse arguments 3383 jint parse_result = Arguments::parse(args); 3384 if (parse_result != JNI_OK) return parse_result; 3385 3386 os::init_before_ergo(); 3387 3388 jint ergo_result = Arguments::apply_ergo(); 3389 if (ergo_result != JNI_OK) return ergo_result; 3390 3391 // Final check of all ranges after ergonomics which may change values. 3392 if (!CommandLineFlagRangeList::check_ranges()) { 3393 return JNI_EINVAL; 3394 } 3395 3396 // Final check of all 'AfterErgo' constraints after ergonomics which may change values. 3397 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo); 3398 if (!constraint_result) { 3399 return JNI_EINVAL; 3400 } 3401 3402 if (PauseAtStartup) { 3403 os::pause(); 3404 } 3405 3406 HOTSPOT_VM_INIT_BEGIN(); 3407 3408 // Timing (must come after argument parsing) 3409 TraceTime timer("Create VM", TraceStartupTime); 3410 3411 // Initialize the os module after parsing the args 3412 jint os_init_2_result = os::init_2(); 3413 if (os_init_2_result != JNI_OK) return os_init_2_result; 3414 3415 jint adjust_after_os_result = Arguments::adjust_after_os(); 3416 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3417 3418 // initialize TLS 3419 ThreadLocalStorage::init(); 3420 3421 // Initialize output stream logging 3422 ostream_init_log(); 3423 3424 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3425 // Must be before create_vm_init_agents() 3426 if (Arguments::init_libraries_at_startup()) { 3427 convert_vm_init_libraries_to_agents(); 3428 } 3429 3430 // Launch -agentlib/-agentpath and converted -Xrun agents 3431 if (Arguments::init_agents_at_startup()) { 3432 create_vm_init_agents(); 3433 } 3434 3435 // Initialize Threads state 3436 _thread_list = NULL; 3437 _number_of_threads = 0; 3438 _number_of_non_daemon_threads = 0; 3439 3440 // Initialize global data structures and create system classes in heap 3441 vm_init_globals(); 3442 3443 #if INCLUDE_JVMCI 3444 if (JVMCICounterSize > 0) { 3445 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 3446 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize); 3447 } else { 3448 JavaThread::_jvmci_old_thread_counters = NULL; 3449 } 3450 #endif // INCLUDE_JVMCI 3451 3452 // Attach the main thread to this os thread 3453 JavaThread* main_thread = new JavaThread(); 3454 main_thread->set_thread_state(_thread_in_vm); 3455 // must do this before set_active_handles and initialize_thread_local_storage 3456 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3457 // change the stack size recorded here to one based on the java thread 3458 // stacksize. This adjusted size is what is used to figure the placement 3459 // of the guard pages. 3460 main_thread->record_stack_base_and_size(); 3461 main_thread->initialize_thread_local_storage(); 3462 3463 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3464 3465 if (!main_thread->set_as_starting_thread()) { 3466 vm_shutdown_during_initialization( 3467 "Failed necessary internal allocation. Out of swap space"); 3468 delete main_thread; 3469 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3470 return JNI_ENOMEM; 3471 } 3472 3473 // Enable guard page *after* os::create_main_thread(), otherwise it would 3474 // crash Linux VM, see notes in os_linux.cpp. 3475 main_thread->create_stack_guard_pages(); 3476 3477 // Initialize Java-Level synchronization subsystem 3478 ObjectMonitor::Initialize(); 3479 3480 // Initialize global modules 3481 jint status = init_globals(); 3482 if (status != JNI_OK) { 3483 delete main_thread; 3484 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3485 return status; 3486 } 3487 3488 // Should be done after the heap is fully created 3489 main_thread->cache_global_variables(); 3490 3491 HandleMark hm; 3492 3493 { MutexLocker mu(Threads_lock); 3494 Threads::add(main_thread); 3495 } 3496 3497 // Any JVMTI raw monitors entered in onload will transition into 3498 // real raw monitor. VM is setup enough here for raw monitor enter. 3499 JvmtiExport::transition_pending_onload_raw_monitors(); 3500 3501 // Create the VMThread 3502 { TraceTime timer("Start VMThread", TraceStartupTime); 3503 VMThread::create(); 3504 Thread* vmthread = VMThread::vm_thread(); 3505 3506 if (!os::create_thread(vmthread, os::vm_thread)) { 3507 vm_exit_during_initialization("Cannot create VM thread. " 3508 "Out of system resources."); 3509 } 3510 3511 // Wait for the VM thread to become ready, and VMThread::run to initialize 3512 // Monitors can have spurious returns, must always check another state flag 3513 { 3514 MutexLocker ml(Notify_lock); 3515 os::start_thread(vmthread); 3516 while (vmthread->active_handles() == NULL) { 3517 Notify_lock->wait(); 3518 } 3519 } 3520 } 3521 3522 assert(Universe::is_fully_initialized(), "not initialized"); 3523 if (VerifyDuringStartup) { 3524 // Make sure we're starting with a clean slate. 3525 VM_Verify verify_op; 3526 VMThread::execute(&verify_op); 3527 } 3528 3529 Thread* THREAD = Thread::current(); 3530 3531 // At this point, the Universe is initialized, but we have not executed 3532 // any byte code. Now is a good time (the only time) to dump out the 3533 // internal state of the JVM for sharing. 3534 if (DumpSharedSpaces) { 3535 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3536 ShouldNotReachHere(); 3537 } 3538 3539 // Always call even when there are not JVMTI environments yet, since environments 3540 // may be attached late and JVMTI must track phases of VM execution 3541 JvmtiExport::enter_start_phase(); 3542 3543 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3544 JvmtiExport::post_vm_start(); 3545 3546 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3547 3548 // We need this for ClassDataSharing - the initial vm.info property is set 3549 // with the default value of CDS "sharing" which may be reset through 3550 // command line options. 3551 reset_vm_info_property(CHECK_JNI_ERR); 3552 3553 quicken_jni_functions(); 3554 3555 // Must be run after init_ft which initializes ft_enabled 3556 if (TRACE_INITIALIZE() != JNI_OK) { 3557 vm_exit_during_initialization("Failed to initialize tracing backend"); 3558 } 3559 3560 // Set flag that basic initialization has completed. Used by exceptions and various 3561 // debug stuff, that does not work until all basic classes have been initialized. 3562 set_init_completed(); 3563 3564 LogConfiguration::post_initialize(); 3565 Metaspace::post_initialize(); 3566 3567 HOTSPOT_VM_INIT_END(); 3568 3569 // record VM initialization completion time 3570 #if INCLUDE_MANAGEMENT 3571 Management::record_vm_init_completed(); 3572 #endif // INCLUDE_MANAGEMENT 3573 3574 // Compute system loader. Note that this has to occur after set_init_completed, since 3575 // valid exceptions may be thrown in the process. 3576 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3577 // set_init_completed has just been called, causing exceptions not to be shortcut 3578 // anymore. We call vm_exit_during_initialization directly instead. 3579 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR)); 3580 3581 #if INCLUDE_ALL_GCS 3582 // Support for ConcurrentMarkSweep. This should be cleaned up 3583 // and better encapsulated. The ugly nested if test would go away 3584 // once things are properly refactored. XXX YSR 3585 if (UseConcMarkSweepGC || UseG1GC) { 3586 if (UseConcMarkSweepGC) { 3587 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3588 } else { 3589 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3590 } 3591 } 3592 #endif // INCLUDE_ALL_GCS 3593 3594 // Always call even when there are not JVMTI environments yet, since environments 3595 // may be attached late and JVMTI must track phases of VM execution 3596 JvmtiExport::enter_live_phase(); 3597 3598 // Signal Dispatcher needs to be started before VMInit event is posted 3599 os::signal_init(); 3600 3601 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3602 if (!DisableAttachMechanism) { 3603 AttachListener::vm_start(); 3604 if (StartAttachListener || AttachListener::init_at_startup()) { 3605 AttachListener::init(); 3606 } 3607 } 3608 3609 // Launch -Xrun agents 3610 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3611 // back-end can launch with -Xdebug -Xrunjdwp. 3612 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3613 create_vm_init_libraries(); 3614 } 3615 3616 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3617 JvmtiExport::post_vm_initialized(); 3618 3619 if (TRACE_START() != JNI_OK) { 3620 vm_exit_during_initialization("Failed to start tracing backend."); 3621 } 3622 3623 if (CleanChunkPoolAsync) { 3624 Chunk::start_chunk_pool_cleaner_task(); 3625 } 3626 3627 #if INCLUDE_JVMCI 3628 if (EnableJVMCI) { 3629 const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler"); 3630 if (jvmciCompiler != NULL) { 3631 JVMCIRuntime::save_compiler(jvmciCompiler); 3632 } 3633 JVMCIRuntime::maybe_print_flags(CHECK_JNI_ERR); 3634 } 3635 #endif // INCLUDE_JVMCI 3636 3637 // initialize compiler(s) 3638 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI 3639 CompileBroker::compilation_init(); 3640 #endif 3641 3642 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3643 // It is done after compilers are initialized, because otherwise compilations of 3644 // signature polymorphic MH intrinsics can be missed 3645 // (see SystemDictionary::find_method_handle_intrinsic). 3646 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3647 3648 #if INCLUDE_MANAGEMENT 3649 Management::initialize(THREAD); 3650 3651 if (HAS_PENDING_EXCEPTION) { 3652 // management agent fails to start possibly due to 3653 // configuration problem and is responsible for printing 3654 // stack trace if appropriate. Simply exit VM. 3655 vm_exit(1); 3656 } 3657 #endif // INCLUDE_MANAGEMENT 3658 3659 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3660 if (MemProfiling) MemProfiler::engage(); 3661 StatSampler::engage(); 3662 if (CheckJNICalls) JniPeriodicChecker::engage(); 3663 3664 BiasedLocking::init(); 3665 3666 #if INCLUDE_RTM_OPT 3667 RTMLockingCounters::init(); 3668 #endif 3669 3670 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3671 call_postVMInitHook(THREAD); 3672 // The Java side of PostVMInitHook.run must deal with all 3673 // exceptions and provide means of diagnosis. 3674 if (HAS_PENDING_EXCEPTION) { 3675 CLEAR_PENDING_EXCEPTION; 3676 } 3677 } 3678 3679 { 3680 MutexLocker ml(PeriodicTask_lock); 3681 // Make sure the WatcherThread can be started by WatcherThread::start() 3682 // or by dynamic enrollment. 3683 WatcherThread::make_startable(); 3684 // Start up the WatcherThread if there are any periodic tasks 3685 // NOTE: All PeriodicTasks should be registered by now. If they 3686 // aren't, late joiners might appear to start slowly (we might 3687 // take a while to process their first tick). 3688 if (PeriodicTask::num_tasks() > 0) { 3689 WatcherThread::start(); 3690 } 3691 } 3692 3693 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM); 3694 3695 create_vm_timer.end(); 3696 #ifdef ASSERT 3697 _vm_complete = true; 3698 #endif 3699 return JNI_OK; 3700 } 3701 3702 // type for the Agent_OnLoad and JVM_OnLoad entry points 3703 extern "C" { 3704 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3705 } 3706 // Find a command line agent library and return its entry point for 3707 // -agentlib: -agentpath: -Xrun 3708 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3709 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 3710 const char *on_load_symbols[], 3711 size_t num_symbol_entries) { 3712 OnLoadEntry_t on_load_entry = NULL; 3713 void *library = NULL; 3714 3715 if (!agent->valid()) { 3716 char buffer[JVM_MAXPATHLEN]; 3717 char ebuf[1024] = ""; 3718 const char *name = agent->name(); 3719 const char *msg = "Could not find agent library "; 3720 3721 // First check to see if agent is statically linked into executable 3722 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3723 library = agent->os_lib(); 3724 } else if (agent->is_absolute_path()) { 3725 library = os::dll_load(name, ebuf, sizeof ebuf); 3726 if (library == NULL) { 3727 const char *sub_msg = " in absolute path, with error: "; 3728 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3729 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3730 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3731 // If we can't find the agent, exit. 3732 vm_exit_during_initialization(buf, NULL); 3733 FREE_C_HEAP_ARRAY(char, buf); 3734 } 3735 } else { 3736 // Try to load the agent from the standard dll directory 3737 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3738 name)) { 3739 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3740 } 3741 if (library == NULL) { // Try the local directory 3742 char ns[1] = {0}; 3743 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3744 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3745 } 3746 if (library == NULL) { 3747 const char *sub_msg = " on the library path, with error: "; 3748 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3749 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3750 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3751 // If we can't find the agent, exit. 3752 vm_exit_during_initialization(buf, NULL); 3753 FREE_C_HEAP_ARRAY(char, buf); 3754 } 3755 } 3756 } 3757 agent->set_os_lib(library); 3758 agent->set_valid(); 3759 } 3760 3761 // Find the OnLoad function. 3762 on_load_entry = 3763 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3764 false, 3765 on_load_symbols, 3766 num_symbol_entries)); 3767 return on_load_entry; 3768 } 3769 3770 // Find the JVM_OnLoad entry point 3771 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3772 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3773 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3774 } 3775 3776 // Find the Agent_OnLoad entry point 3777 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3778 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3779 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3780 } 3781 3782 // For backwards compatibility with -Xrun 3783 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3784 // treated like -agentpath: 3785 // Must be called before agent libraries are created 3786 void Threads::convert_vm_init_libraries_to_agents() { 3787 AgentLibrary* agent; 3788 AgentLibrary* next; 3789 3790 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3791 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3792 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3793 3794 // If there is an JVM_OnLoad function it will get called later, 3795 // otherwise see if there is an Agent_OnLoad 3796 if (on_load_entry == NULL) { 3797 on_load_entry = lookup_agent_on_load(agent); 3798 if (on_load_entry != NULL) { 3799 // switch it to the agent list -- so that Agent_OnLoad will be called, 3800 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3801 Arguments::convert_library_to_agent(agent); 3802 } else { 3803 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3804 } 3805 } 3806 } 3807 } 3808 3809 // Create agents for -agentlib: -agentpath: and converted -Xrun 3810 // Invokes Agent_OnLoad 3811 // Called very early -- before JavaThreads exist 3812 void Threads::create_vm_init_agents() { 3813 extern struct JavaVM_ main_vm; 3814 AgentLibrary* agent; 3815 3816 JvmtiExport::enter_onload_phase(); 3817 3818 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3819 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3820 3821 if (on_load_entry != NULL) { 3822 // Invoke the Agent_OnLoad function 3823 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3824 if (err != JNI_OK) { 3825 vm_exit_during_initialization("agent library failed to init", agent->name()); 3826 } 3827 } else { 3828 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3829 } 3830 } 3831 JvmtiExport::enter_primordial_phase(); 3832 } 3833 3834 extern "C" { 3835 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3836 } 3837 3838 void Threads::shutdown_vm_agents() { 3839 // Send any Agent_OnUnload notifications 3840 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3841 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3842 extern struct JavaVM_ main_vm; 3843 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3844 3845 // Find the Agent_OnUnload function. 3846 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3847 os::find_agent_function(agent, 3848 false, 3849 on_unload_symbols, 3850 num_symbol_entries)); 3851 3852 // Invoke the Agent_OnUnload function 3853 if (unload_entry != NULL) { 3854 JavaThread* thread = JavaThread::current(); 3855 ThreadToNativeFromVM ttn(thread); 3856 HandleMark hm(thread); 3857 (*unload_entry)(&main_vm); 3858 } 3859 } 3860 } 3861 3862 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3863 // Invokes JVM_OnLoad 3864 void Threads::create_vm_init_libraries() { 3865 extern struct JavaVM_ main_vm; 3866 AgentLibrary* agent; 3867 3868 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3869 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3870 3871 if (on_load_entry != NULL) { 3872 // Invoke the JVM_OnLoad function 3873 JavaThread* thread = JavaThread::current(); 3874 ThreadToNativeFromVM ttn(thread); 3875 HandleMark hm(thread); 3876 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3877 if (err != JNI_OK) { 3878 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3879 } 3880 } else { 3881 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3882 } 3883 } 3884 } 3885 3886 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3887 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3888 3889 JavaThread* java_thread = NULL; 3890 // Sequential search for now. Need to do better optimization later. 3891 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3892 oop tobj = thread->threadObj(); 3893 if (!thread->is_exiting() && 3894 tobj != NULL && 3895 java_tid == java_lang_Thread::thread_id(tobj)) { 3896 java_thread = thread; 3897 break; 3898 } 3899 } 3900 return java_thread; 3901 } 3902 3903 3904 // Last thread running calls java.lang.Shutdown.shutdown() 3905 void JavaThread::invoke_shutdown_hooks() { 3906 HandleMark hm(this); 3907 3908 // We could get here with a pending exception, if so clear it now. 3909 if (this->has_pending_exception()) { 3910 this->clear_pending_exception(); 3911 } 3912 3913 EXCEPTION_MARK; 3914 Klass* k = 3915 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3916 THREAD); 3917 if (k != NULL) { 3918 // SystemDictionary::resolve_or_null will return null if there was 3919 // an exception. If we cannot load the Shutdown class, just don't 3920 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3921 // and finalizers (if runFinalizersOnExit is set) won't be run. 3922 // Note that if a shutdown hook was registered or runFinalizersOnExit 3923 // was called, the Shutdown class would have already been loaded 3924 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3925 instanceKlassHandle shutdown_klass (THREAD, k); 3926 JavaValue result(T_VOID); 3927 JavaCalls::call_static(&result, 3928 shutdown_klass, 3929 vmSymbols::shutdown_method_name(), 3930 vmSymbols::void_method_signature(), 3931 THREAD); 3932 } 3933 CLEAR_PENDING_EXCEPTION; 3934 } 3935 3936 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3937 // the program falls off the end of main(). Another VM exit path is through 3938 // vm_exit() when the program calls System.exit() to return a value or when 3939 // there is a serious error in VM. The two shutdown paths are not exactly 3940 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3941 // and VM_Exit op at VM level. 3942 // 3943 // Shutdown sequence: 3944 // + Shutdown native memory tracking if it is on 3945 // + Wait until we are the last non-daemon thread to execute 3946 // <-- every thing is still working at this moment --> 3947 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3948 // shutdown hooks, run finalizers if finalization-on-exit 3949 // + Call before_exit(), prepare for VM exit 3950 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3951 // currently the only user of this mechanism is File.deleteOnExit()) 3952 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3953 // post thread end and vm death events to JVMTI, 3954 // stop signal thread 3955 // + Call JavaThread::exit(), it will: 3956 // > release JNI handle blocks, remove stack guard pages 3957 // > remove this thread from Threads list 3958 // <-- no more Java code from this thread after this point --> 3959 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3960 // the compiler threads at safepoint 3961 // <-- do not use anything that could get blocked by Safepoint --> 3962 // + Disable tracing at JNI/JVM barriers 3963 // + Set _vm_exited flag for threads that are still running native code 3964 // + Delete this thread 3965 // + Call exit_globals() 3966 // > deletes tty 3967 // > deletes PerfMemory resources 3968 // + Return to caller 3969 3970 bool Threads::destroy_vm() { 3971 JavaThread* thread = JavaThread::current(); 3972 3973 #ifdef ASSERT 3974 _vm_complete = false; 3975 #endif 3976 // Wait until we are the last non-daemon thread to execute 3977 { MutexLocker nu(Threads_lock); 3978 while (Threads::number_of_non_daemon_threads() > 1) 3979 // This wait should make safepoint checks, wait without a timeout, 3980 // and wait as a suspend-equivalent condition. 3981 // 3982 // Note: If the FlatProfiler is running and this thread is waiting 3983 // for another non-daemon thread to finish, then the FlatProfiler 3984 // is waiting for the external suspend request on this thread to 3985 // complete. wait_for_ext_suspend_completion() will eventually 3986 // timeout, but that takes time. Making this wait a suspend- 3987 // equivalent condition solves that timeout problem. 3988 // 3989 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3990 Mutex::_as_suspend_equivalent_flag); 3991 } 3992 3993 // Hang forever on exit if we are reporting an error. 3994 if (ShowMessageBoxOnError && is_error_reported()) { 3995 os::infinite_sleep(); 3996 } 3997 os::wait_for_keypress_at_exit(); 3998 3999 // run Java level shutdown hooks 4000 thread->invoke_shutdown_hooks(); 4001 4002 before_exit(thread); 4003 4004 thread->exit(true); 4005 4006 // Stop VM thread. 4007 { 4008 // 4945125 The vm thread comes to a safepoint during exit. 4009 // GC vm_operations can get caught at the safepoint, and the 4010 // heap is unparseable if they are caught. Grab the Heap_lock 4011 // to prevent this. The GC vm_operations will not be able to 4012 // queue until after the vm thread is dead. After this point, 4013 // we'll never emerge out of the safepoint before the VM exits. 4014 4015 MutexLocker ml(Heap_lock); 4016 4017 VMThread::wait_for_vm_thread_exit(); 4018 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4019 VMThread::destroy(); 4020 } 4021 4022 // clean up ideal graph printers 4023 #if defined(COMPILER2) && !defined(PRODUCT) 4024 IdealGraphPrinter::clean_up(); 4025 #endif 4026 4027 // Now, all Java threads are gone except daemon threads. Daemon threads 4028 // running Java code or in VM are stopped by the Safepoint. However, 4029 // daemon threads executing native code are still running. But they 4030 // will be stopped at native=>Java/VM barriers. Note that we can't 4031 // simply kill or suspend them, as it is inherently deadlock-prone. 4032 4033 #ifndef PRODUCT 4034 // disable function tracing at JNI/JVM barriers 4035 TraceJNICalls = false; 4036 TraceJVMCalls = false; 4037 TraceRuntimeCalls = false; 4038 #endif 4039 4040 VM_Exit::set_vm_exited(); 4041 4042 notify_vm_shutdown(); 4043 4044 delete thread; 4045 4046 #if INCLUDE_JVMCI 4047 if (JVMCICounterSize > 0) { 4048 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters); 4049 } 4050 #endif 4051 4052 // exit_globals() will delete tty 4053 exit_globals(); 4054 4055 LogConfiguration::finalize(); 4056 4057 return true; 4058 } 4059 4060 4061 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4062 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4063 return is_supported_jni_version(version); 4064 } 4065 4066 4067 jboolean Threads::is_supported_jni_version(jint version) { 4068 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4069 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4070 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4071 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4072 return JNI_FALSE; 4073 } 4074 4075 4076 void Threads::add(JavaThread* p, bool force_daemon) { 4077 // The threads lock must be owned at this point 4078 assert_locked_or_safepoint(Threads_lock); 4079 4080 // See the comment for this method in thread.hpp for its purpose and 4081 // why it is called here. 4082 p->initialize_queues(); 4083 p->set_next(_thread_list); 4084 _thread_list = p; 4085 _number_of_threads++; 4086 oop threadObj = p->threadObj(); 4087 bool daemon = true; 4088 // Bootstrapping problem: threadObj can be null for initial 4089 // JavaThread (or for threads attached via JNI) 4090 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4091 _number_of_non_daemon_threads++; 4092 daemon = false; 4093 } 4094 4095 ThreadService::add_thread(p, daemon); 4096 4097 // Possible GC point. 4098 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p)); 4099 } 4100 4101 void Threads::remove(JavaThread* p) { 4102 // Extra scope needed for Thread_lock, so we can check 4103 // that we do not remove thread without safepoint code notice 4104 { MutexLocker ml(Threads_lock); 4105 4106 assert(includes(p), "p must be present"); 4107 4108 JavaThread* current = _thread_list; 4109 JavaThread* prev = NULL; 4110 4111 while (current != p) { 4112 prev = current; 4113 current = current->next(); 4114 } 4115 4116 if (prev) { 4117 prev->set_next(current->next()); 4118 } else { 4119 _thread_list = p->next(); 4120 } 4121 _number_of_threads--; 4122 oop threadObj = p->threadObj(); 4123 bool daemon = true; 4124 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4125 _number_of_non_daemon_threads--; 4126 daemon = false; 4127 4128 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4129 // on destroy_vm will wake up. 4130 if (number_of_non_daemon_threads() == 1) { 4131 Threads_lock->notify_all(); 4132 } 4133 } 4134 ThreadService::remove_thread(p, daemon); 4135 4136 // Make sure that safepoint code disregard this thread. This is needed since 4137 // the thread might mess around with locks after this point. This can cause it 4138 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4139 // of this thread since it is removed from the queue. 4140 p->set_terminated_value(); 4141 } // unlock Threads_lock 4142 4143 // Since Events::log uses a lock, we grab it outside the Threads_lock 4144 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p)); 4145 } 4146 4147 // Threads_lock must be held when this is called (or must be called during a safepoint) 4148 bool Threads::includes(JavaThread* p) { 4149 assert(Threads_lock->is_locked(), "sanity check"); 4150 ALL_JAVA_THREADS(q) { 4151 if (q == p) { 4152 return true; 4153 } 4154 } 4155 return false; 4156 } 4157 4158 // Operations on the Threads list for GC. These are not explicitly locked, 4159 // but the garbage collector must provide a safe context for them to run. 4160 // In particular, these things should never be called when the Threads_lock 4161 // is held by some other thread. (Note: the Safepoint abstraction also 4162 // uses the Threads_lock to guarantee this property. It also makes sure that 4163 // all threads gets blocked when exiting or starting). 4164 4165 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4166 ALL_JAVA_THREADS(p) { 4167 p->oops_do(f, cld_f, cf); 4168 } 4169 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4170 } 4171 4172 void Threads::change_thread_claim_parity() { 4173 // Set the new claim parity. 4174 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2, 4175 "Not in range."); 4176 _thread_claim_parity++; 4177 if (_thread_claim_parity == 3) _thread_claim_parity = 1; 4178 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2, 4179 "Not in range."); 4180 } 4181 4182 #ifdef ASSERT 4183 void Threads::assert_all_threads_claimed() { 4184 ALL_JAVA_THREADS(p) { 4185 const int thread_parity = p->oops_do_parity(); 4186 assert((thread_parity == _thread_claim_parity), 4187 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity); 4188 } 4189 } 4190 #endif // ASSERT 4191 4192 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4193 int cp = Threads::thread_claim_parity(); 4194 ALL_JAVA_THREADS(p) { 4195 if (p->claim_oops_do(is_par, cp)) { 4196 p->oops_do(f, cld_f, cf); 4197 } 4198 } 4199 VMThread* vmt = VMThread::vm_thread(); 4200 if (vmt->claim_oops_do(is_par, cp)) { 4201 vmt->oops_do(f, cld_f, cf); 4202 } 4203 } 4204 4205 #if INCLUDE_ALL_GCS 4206 // Used by ParallelScavenge 4207 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4208 ALL_JAVA_THREADS(p) { 4209 q->enqueue(new ThreadRootsTask(p)); 4210 } 4211 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4212 } 4213 4214 // Used by Parallel Old 4215 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4216 ALL_JAVA_THREADS(p) { 4217 q->enqueue(new ThreadRootsMarkingTask(p)); 4218 } 4219 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4220 } 4221 #endif // INCLUDE_ALL_GCS 4222 4223 void Threads::nmethods_do(CodeBlobClosure* cf) { 4224 ALL_JAVA_THREADS(p) { 4225 p->nmethods_do(cf); 4226 } 4227 VMThread::vm_thread()->nmethods_do(cf); 4228 } 4229 4230 void Threads::metadata_do(void f(Metadata*)) { 4231 ALL_JAVA_THREADS(p) { 4232 p->metadata_do(f); 4233 } 4234 } 4235 4236 class ThreadHandlesClosure : public ThreadClosure { 4237 void (*_f)(Metadata*); 4238 public: 4239 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4240 virtual void do_thread(Thread* thread) { 4241 thread->metadata_handles_do(_f); 4242 } 4243 }; 4244 4245 void Threads::metadata_handles_do(void f(Metadata*)) { 4246 // Only walk the Handles in Thread. 4247 ThreadHandlesClosure handles_closure(f); 4248 threads_do(&handles_closure); 4249 } 4250 4251 void Threads::deoptimized_wrt_marked_nmethods() { 4252 ALL_JAVA_THREADS(p) { 4253 p->deoptimized_wrt_marked_nmethods(); 4254 } 4255 } 4256 4257 4258 // Get count Java threads that are waiting to enter the specified monitor. 4259 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4260 address monitor, 4261 bool doLock) { 4262 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4263 "must grab Threads_lock or be at safepoint"); 4264 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4265 4266 int i = 0; 4267 { 4268 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4269 ALL_JAVA_THREADS(p) { 4270 if (!p->can_call_java()) continue; 4271 4272 address pending = (address)p->current_pending_monitor(); 4273 if (pending == monitor) { // found a match 4274 if (i < count) result->append(p); // save the first count matches 4275 i++; 4276 } 4277 } 4278 } 4279 return result; 4280 } 4281 4282 4283 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, 4284 bool doLock) { 4285 assert(doLock || 4286 Threads_lock->owned_by_self() || 4287 SafepointSynchronize::is_at_safepoint(), 4288 "must grab Threads_lock or be at safepoint"); 4289 4290 // NULL owner means not locked so we can skip the search 4291 if (owner == NULL) return NULL; 4292 4293 { 4294 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4295 ALL_JAVA_THREADS(p) { 4296 // first, see if owner is the address of a Java thread 4297 if (owner == (address)p) return p; 4298 } 4299 } 4300 // Cannot assert on lack of success here since this function may be 4301 // used by code that is trying to report useful problem information 4302 // like deadlock detection. 4303 if (UseHeavyMonitors) return NULL; 4304 4305 // If we didn't find a matching Java thread and we didn't force use of 4306 // heavyweight monitors, then the owner is the stack address of the 4307 // Lock Word in the owning Java thread's stack. 4308 // 4309 JavaThread* the_owner = NULL; 4310 { 4311 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4312 ALL_JAVA_THREADS(q) { 4313 if (q->is_lock_owned(owner)) { 4314 the_owner = q; 4315 break; 4316 } 4317 } 4318 } 4319 // cannot assert on lack of success here; see above comment 4320 return the_owner; 4321 } 4322 4323 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4324 void Threads::print_on(outputStream* st, bool print_stacks, 4325 bool internal_format, bool print_concurrent_locks) { 4326 char buf[32]; 4327 st->print_raw_cr(os::local_time_string(buf, sizeof(buf))); 4328 4329 st->print_cr("Full thread dump %s (%s %s):", 4330 Abstract_VM_Version::vm_name(), 4331 Abstract_VM_Version::vm_release(), 4332 Abstract_VM_Version::vm_info_string()); 4333 st->cr(); 4334 4335 #if INCLUDE_SERVICES 4336 // Dump concurrent locks 4337 ConcurrentLocksDump concurrent_locks; 4338 if (print_concurrent_locks) { 4339 concurrent_locks.dump_at_safepoint(); 4340 } 4341 #endif // INCLUDE_SERVICES 4342 4343 ALL_JAVA_THREADS(p) { 4344 ResourceMark rm; 4345 p->print_on(st); 4346 if (print_stacks) { 4347 if (internal_format) { 4348 p->trace_stack(); 4349 } else { 4350 p->print_stack_on(st); 4351 } 4352 } 4353 st->cr(); 4354 #if INCLUDE_SERVICES 4355 if (print_concurrent_locks) { 4356 concurrent_locks.print_locks_on(p, st); 4357 } 4358 #endif // INCLUDE_SERVICES 4359 } 4360 4361 VMThread::vm_thread()->print_on(st); 4362 st->cr(); 4363 Universe::heap()->print_gc_threads_on(st); 4364 WatcherThread* wt = WatcherThread::watcher_thread(); 4365 if (wt != NULL) { 4366 wt->print_on(st); 4367 st->cr(); 4368 } 4369 CompileBroker::print_compiler_threads_on(st); 4370 st->flush(); 4371 } 4372 4373 // Threads::print_on_error() is called by fatal error handler. It's possible 4374 // that VM is not at safepoint and/or current thread is inside signal handler. 4375 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4376 // memory (even in resource area), it might deadlock the error handler. 4377 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4378 int buflen) { 4379 bool found_current = false; 4380 st->print_cr("Java Threads: ( => current thread )"); 4381 ALL_JAVA_THREADS(thread) { 4382 bool is_current = (current == thread); 4383 found_current = found_current || is_current; 4384 4385 st->print("%s", is_current ? "=>" : " "); 4386 4387 st->print(PTR_FORMAT, p2i(thread)); 4388 st->print(" "); 4389 thread->print_on_error(st, buf, buflen); 4390 st->cr(); 4391 } 4392 st->cr(); 4393 4394 st->print_cr("Other Threads:"); 4395 if (VMThread::vm_thread()) { 4396 bool is_current = (current == VMThread::vm_thread()); 4397 found_current = found_current || is_current; 4398 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4399 4400 st->print(PTR_FORMAT, p2i(VMThread::vm_thread())); 4401 st->print(" "); 4402 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4403 st->cr(); 4404 } 4405 WatcherThread* wt = WatcherThread::watcher_thread(); 4406 if (wt != NULL) { 4407 bool is_current = (current == wt); 4408 found_current = found_current || is_current; 4409 st->print("%s", is_current ? "=>" : " "); 4410 4411 st->print(PTR_FORMAT, p2i(wt)); 4412 st->print(" "); 4413 wt->print_on_error(st, buf, buflen); 4414 st->cr(); 4415 } 4416 if (!found_current) { 4417 st->cr(); 4418 st->print("=>" PTR_FORMAT " (exited) ", p2i(current)); 4419 current->print_on_error(st, buf, buflen); 4420 st->cr(); 4421 } 4422 } 4423 4424 // Internal SpinLock and Mutex 4425 // Based on ParkEvent 4426 4427 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4428 // 4429 // We employ SpinLocks _only for low-contention, fixed-length 4430 // short-duration critical sections where we're concerned 4431 // about native mutex_t or HotSpot Mutex:: latency. 4432 // The mux construct provides a spin-then-block mutual exclusion 4433 // mechanism. 4434 // 4435 // Testing has shown that contention on the ListLock guarding gFreeList 4436 // is common. If we implement ListLock as a simple SpinLock it's common 4437 // for the JVM to devolve to yielding with little progress. This is true 4438 // despite the fact that the critical sections protected by ListLock are 4439 // extremely short. 4440 // 4441 // TODO-FIXME: ListLock should be of type SpinLock. 4442 // We should make this a 1st-class type, integrated into the lock 4443 // hierarchy as leaf-locks. Critically, the SpinLock structure 4444 // should have sufficient padding to avoid false-sharing and excessive 4445 // cache-coherency traffic. 4446 4447 4448 typedef volatile int SpinLockT; 4449 4450 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4451 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4452 return; // normal fast-path return 4453 } 4454 4455 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4456 TEVENT(SpinAcquire - ctx); 4457 int ctr = 0; 4458 int Yields = 0; 4459 for (;;) { 4460 while (*adr != 0) { 4461 ++ctr; 4462 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4463 if (Yields > 5) { 4464 os::naked_short_sleep(1); 4465 } else { 4466 os::naked_yield(); 4467 ++Yields; 4468 } 4469 } else { 4470 SpinPause(); 4471 } 4472 } 4473 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4474 } 4475 } 4476 4477 void Thread::SpinRelease(volatile int * adr) { 4478 assert(*adr != 0, "invariant"); 4479 OrderAccess::fence(); // guarantee at least release consistency. 4480 // Roach-motel semantics. 4481 // It's safe if subsequent LDs and STs float "up" into the critical section, 4482 // but prior LDs and STs within the critical section can't be allowed 4483 // to reorder or float past the ST that releases the lock. 4484 // Loads and stores in the critical section - which appear in program 4485 // order before the store that releases the lock - must also appear 4486 // before the store that releases the lock in memory visibility order. 4487 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4488 // the ST of 0 into the lock-word which releases the lock, so fence 4489 // more than covers this on all platforms. 4490 *adr = 0; 4491 } 4492 4493 // muxAcquire and muxRelease: 4494 // 4495 // * muxAcquire and muxRelease support a single-word lock-word construct. 4496 // The LSB of the word is set IFF the lock is held. 4497 // The remainder of the word points to the head of a singly-linked list 4498 // of threads blocked on the lock. 4499 // 4500 // * The current implementation of muxAcquire-muxRelease uses its own 4501 // dedicated Thread._MuxEvent instance. If we're interested in 4502 // minimizing the peak number of extant ParkEvent instances then 4503 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4504 // as certain invariants were satisfied. Specifically, care would need 4505 // to be taken with regards to consuming unpark() "permits". 4506 // A safe rule of thumb is that a thread would never call muxAcquire() 4507 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4508 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4509 // consume an unpark() permit intended for monitorenter, for instance. 4510 // One way around this would be to widen the restricted-range semaphore 4511 // implemented in park(). Another alternative would be to provide 4512 // multiple instances of the PlatformEvent() for each thread. One 4513 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4514 // 4515 // * Usage: 4516 // -- Only as leaf locks 4517 // -- for short-term locking only as muxAcquire does not perform 4518 // thread state transitions. 4519 // 4520 // Alternatives: 4521 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4522 // but with parking or spin-then-park instead of pure spinning. 4523 // * Use Taura-Oyama-Yonenzawa locks. 4524 // * It's possible to construct a 1-0 lock if we encode the lockword as 4525 // (List,LockByte). Acquire will CAS the full lockword while Release 4526 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4527 // acquiring threads use timers (ParkTimed) to detect and recover from 4528 // the stranding window. Thread/Node structures must be aligned on 256-byte 4529 // boundaries by using placement-new. 4530 // * Augment MCS with advisory back-link fields maintained with CAS(). 4531 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4532 // The validity of the backlinks must be ratified before we trust the value. 4533 // If the backlinks are invalid the exiting thread must back-track through the 4534 // the forward links, which are always trustworthy. 4535 // * Add a successor indication. The LockWord is currently encoded as 4536 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4537 // to provide the usual futile-wakeup optimization. 4538 // See RTStt for details. 4539 // * Consider schedctl.sc_nopreempt to cover the critical section. 4540 // 4541 4542 4543 typedef volatile intptr_t MutexT; // Mux Lock-word 4544 enum MuxBits { LOCKBIT = 1 }; 4545 4546 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4547 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4548 if (w == 0) return; 4549 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4550 return; 4551 } 4552 4553 TEVENT(muxAcquire - Contention); 4554 ParkEvent * const Self = Thread::current()->_MuxEvent; 4555 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4556 for (;;) { 4557 int its = (os::is_MP() ? 100 : 0) + 1; 4558 4559 // Optional spin phase: spin-then-park strategy 4560 while (--its >= 0) { 4561 w = *Lock; 4562 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4563 return; 4564 } 4565 } 4566 4567 Self->reset(); 4568 Self->OnList = intptr_t(Lock); 4569 // The following fence() isn't _strictly necessary as the subsequent 4570 // CAS() both serializes execution and ratifies the fetched *Lock value. 4571 OrderAccess::fence(); 4572 for (;;) { 4573 w = *Lock; 4574 if ((w & LOCKBIT) == 0) { 4575 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4576 Self->OnList = 0; // hygiene - allows stronger asserts 4577 return; 4578 } 4579 continue; // Interference -- *Lock changed -- Just retry 4580 } 4581 assert(w & LOCKBIT, "invariant"); 4582 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4583 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4584 } 4585 4586 while (Self->OnList != 0) { 4587 Self->park(); 4588 } 4589 } 4590 } 4591 4592 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4593 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4594 if (w == 0) return; 4595 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4596 return; 4597 } 4598 4599 TEVENT(muxAcquire - Contention); 4600 ParkEvent * ReleaseAfter = NULL; 4601 if (ev == NULL) { 4602 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4603 } 4604 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4605 for (;;) { 4606 guarantee(ev->OnList == 0, "invariant"); 4607 int its = (os::is_MP() ? 100 : 0) + 1; 4608 4609 // Optional spin phase: spin-then-park strategy 4610 while (--its >= 0) { 4611 w = *Lock; 4612 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4613 if (ReleaseAfter != NULL) { 4614 ParkEvent::Release(ReleaseAfter); 4615 } 4616 return; 4617 } 4618 } 4619 4620 ev->reset(); 4621 ev->OnList = intptr_t(Lock); 4622 // The following fence() isn't _strictly necessary as the subsequent 4623 // CAS() both serializes execution and ratifies the fetched *Lock value. 4624 OrderAccess::fence(); 4625 for (;;) { 4626 w = *Lock; 4627 if ((w & LOCKBIT) == 0) { 4628 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4629 ev->OnList = 0; 4630 // We call ::Release while holding the outer lock, thus 4631 // artificially lengthening the critical section. 4632 // Consider deferring the ::Release() until the subsequent unlock(), 4633 // after we've dropped the outer lock. 4634 if (ReleaseAfter != NULL) { 4635 ParkEvent::Release(ReleaseAfter); 4636 } 4637 return; 4638 } 4639 continue; // Interference -- *Lock changed -- Just retry 4640 } 4641 assert(w & LOCKBIT, "invariant"); 4642 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4643 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4644 } 4645 4646 while (ev->OnList != 0) { 4647 ev->park(); 4648 } 4649 } 4650 } 4651 4652 // Release() must extract a successor from the list and then wake that thread. 4653 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4654 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4655 // Release() would : 4656 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4657 // (B) Extract a successor from the private list "in-hand" 4658 // (C) attempt to CAS() the residual back into *Lock over null. 4659 // If there were any newly arrived threads and the CAS() would fail. 4660 // In that case Release() would detach the RATs, re-merge the list in-hand 4661 // with the RATs and repeat as needed. Alternately, Release() might 4662 // detach and extract a successor, but then pass the residual list to the wakee. 4663 // The wakee would be responsible for reattaching and remerging before it 4664 // competed for the lock. 4665 // 4666 // Both "pop" and DMR are immune from ABA corruption -- there can be 4667 // multiple concurrent pushers, but only one popper or detacher. 4668 // This implementation pops from the head of the list. This is unfair, 4669 // but tends to provide excellent throughput as hot threads remain hot. 4670 // (We wake recently run threads first). 4671 // 4672 // All paths through muxRelease() will execute a CAS. 4673 // Release consistency -- We depend on the CAS in muxRelease() to provide full 4674 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4675 // executed within the critical section are complete and globally visible before the 4676 // store (CAS) to the lock-word that releases the lock becomes globally visible. 4677 void Thread::muxRelease(volatile intptr_t * Lock) { 4678 for (;;) { 4679 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4680 assert(w & LOCKBIT, "invariant"); 4681 if (w == LOCKBIT) return; 4682 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4683 assert(List != NULL, "invariant"); 4684 assert(List->OnList == intptr_t(Lock), "invariant"); 4685 ParkEvent * const nxt = List->ListNext; 4686 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4687 4688 // The following CAS() releases the lock and pops the head element. 4689 // The CAS() also ratifies the previously fetched lock-word value. 4690 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4691 continue; 4692 } 4693 List->OnList = 0; 4694 OrderAccess::fence(); 4695 List->unpark(); 4696 return; 4697 } 4698 } 4699 4700 4701 void Threads::verify() { 4702 ALL_JAVA_THREADS(p) { 4703 p->verify(); 4704 } 4705 VMThread* thread = VMThread::vm_thread(); 4706 if (thread != NULL) thread->verify(); 4707 }