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