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. A detach operation must only 1806 // get here if there are no Java frames on the stack. Therefore, any 1807 // owned monitors at this point MUST be JNI-acquired monitors which are 1808 // pre-inflated and in the monitor cache. 1809 // 1810 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1811 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1812 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1813 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1814 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1815 } 1816 1817 // These things needs to be done while we are still a Java Thread. Make sure that thread 1818 // is in a consistent state, in case GC happens 1819 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1820 1821 if (active_handles() != NULL) { 1822 JNIHandleBlock* block = active_handles(); 1823 set_active_handles(NULL); 1824 JNIHandleBlock::release_block(block); 1825 } 1826 1827 if (free_handle_block() != NULL) { 1828 JNIHandleBlock* block = free_handle_block(); 1829 set_free_handle_block(NULL); 1830 JNIHandleBlock::release_block(block); 1831 } 1832 1833 // These have to be removed while this is still a valid thread. 1834 remove_stack_guard_pages(); 1835 1836 if (UseTLAB) { 1837 tlab().make_parsable(true); // retire TLAB 1838 } 1839 1840 if (JvmtiEnv::environments_might_exist()) { 1841 JvmtiExport::cleanup_thread(this); 1842 } 1843 1844 // We must flush any deferred card marks before removing a thread from 1845 // the list of active threads. 1846 Universe::heap()->flush_deferred_store_barrier(this); 1847 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1848 1849 #if INCLUDE_ALL_GCS 1850 // We must flush the G1-related buffers before removing a thread 1851 // from the list of active threads. We must do this after any deferred 1852 // card marks have been flushed (above) so that any entries that are 1853 // added to the thread's dirty card queue as a result are not lost. 1854 if (UseG1GC) { 1855 flush_barrier_queues(); 1856 } 1857 #endif // INCLUDE_ALL_GCS 1858 1859 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1860 Threads::remove(this); 1861 } 1862 1863 #if INCLUDE_ALL_GCS 1864 // Flush G1-related queues. 1865 void JavaThread::flush_barrier_queues() { 1866 satb_mark_queue().flush(); 1867 dirty_card_queue().flush(); 1868 } 1869 1870 void JavaThread::initialize_queues() { 1871 assert(!SafepointSynchronize::is_at_safepoint(), 1872 "we should not be at a safepoint"); 1873 1874 ObjPtrQueue& satb_queue = satb_mark_queue(); 1875 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1876 // The SATB queue should have been constructed with its active 1877 // field set to false. 1878 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1879 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1880 // If we are creating the thread during a marking cycle, we should 1881 // set the active field of the SATB queue to true. 1882 if (satb_queue_set.is_active()) { 1883 satb_queue.set_active(true); 1884 } 1885 1886 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1887 // The dirty card queue should have been constructed with its 1888 // active field set to true. 1889 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1890 } 1891 #endif // INCLUDE_ALL_GCS 1892 1893 void JavaThread::cleanup_failed_attach_current_thread() { 1894 if (get_thread_profiler() != NULL) { 1895 get_thread_profiler()->disengage(); 1896 ResourceMark rm; 1897 get_thread_profiler()->print(get_thread_name()); 1898 } 1899 1900 if (active_handles() != NULL) { 1901 JNIHandleBlock* block = active_handles(); 1902 set_active_handles(NULL); 1903 JNIHandleBlock::release_block(block); 1904 } 1905 1906 if (free_handle_block() != NULL) { 1907 JNIHandleBlock* block = free_handle_block(); 1908 set_free_handle_block(NULL); 1909 JNIHandleBlock::release_block(block); 1910 } 1911 1912 // These have to be removed while this is still a valid thread. 1913 remove_stack_guard_pages(); 1914 1915 if (UseTLAB) { 1916 tlab().make_parsable(true); // retire TLAB, if any 1917 } 1918 1919 #if INCLUDE_ALL_GCS 1920 if (UseG1GC) { 1921 flush_barrier_queues(); 1922 } 1923 #endif // INCLUDE_ALL_GCS 1924 1925 Threads::remove(this); 1926 delete this; 1927 } 1928 1929 1930 1931 1932 JavaThread* JavaThread::active() { 1933 Thread* thread = ThreadLocalStorage::thread(); 1934 assert(thread != NULL, "just checking"); 1935 if (thread->is_Java_thread()) { 1936 return (JavaThread*) thread; 1937 } else { 1938 assert(thread->is_VM_thread(), "this must be a vm thread"); 1939 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1940 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1941 assert(ret->is_Java_thread(), "must be a Java thread"); 1942 return ret; 1943 } 1944 } 1945 1946 bool JavaThread::is_lock_owned(address adr) const { 1947 if (Thread::is_lock_owned(adr)) return true; 1948 1949 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1950 if (chunk->contains(adr)) return true; 1951 } 1952 1953 return false; 1954 } 1955 1956 1957 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1958 chunk->set_next(monitor_chunks()); 1959 set_monitor_chunks(chunk); 1960 } 1961 1962 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1963 guarantee(monitor_chunks() != NULL, "must be non empty"); 1964 if (monitor_chunks() == chunk) { 1965 set_monitor_chunks(chunk->next()); 1966 } else { 1967 MonitorChunk* prev = monitor_chunks(); 1968 while (prev->next() != chunk) prev = prev->next(); 1969 prev->set_next(chunk->next()); 1970 } 1971 } 1972 1973 // JVM support. 1974 1975 // Note: this function shouldn't block if it's called in 1976 // _thread_in_native_trans state (such as from 1977 // check_special_condition_for_native_trans()). 1978 void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 1979 1980 if (has_last_Java_frame() && has_async_condition()) { 1981 // If we are at a polling page safepoint (not a poll return) 1982 // then we must defer async exception because live registers 1983 // will be clobbered by the exception path. Poll return is 1984 // ok because the call we a returning from already collides 1985 // with exception handling registers and so there is no issue. 1986 // (The exception handling path kills call result registers but 1987 // this is ok since the exception kills the result anyway). 1988 1989 if (is_at_poll_safepoint()) { 1990 // if the code we are returning to has deoptimized we must defer 1991 // the exception otherwise live registers get clobbered on the 1992 // exception path before deoptimization is able to retrieve them. 1993 // 1994 RegisterMap map(this, false); 1995 frame caller_fr = last_frame().sender(&map); 1996 assert(caller_fr.is_compiled_frame(), "what?"); 1997 if (caller_fr.is_deoptimized_frame()) { 1998 if (TraceExceptions) { 1999 ResourceMark rm; 2000 tty->print_cr("deferred async exception at compiled safepoint"); 2001 } 2002 return; 2003 } 2004 } 2005 } 2006 2007 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2008 if (condition == _no_async_condition) { 2009 // Conditions have changed since has_special_runtime_exit_condition() 2010 // was called: 2011 // - if we were here only because of an external suspend request, 2012 // then that was taken care of above (or cancelled) so we are done 2013 // - if we were here because of another async request, then it has 2014 // been cleared between the has_special_runtime_exit_condition() 2015 // and now so again we are done 2016 return; 2017 } 2018 2019 // Check for pending async. exception 2020 if (_pending_async_exception != NULL) { 2021 // Only overwrite an already pending exception, if it is not a threadDeath. 2022 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2023 2024 // We cannot call Exceptions::_throw(...) here because we cannot block 2025 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2026 2027 if (TraceExceptions) { 2028 ResourceMark rm; 2029 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2030 if (has_last_Java_frame()) { 2031 frame f = last_frame(); 2032 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2033 } 2034 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2035 } 2036 _pending_async_exception = NULL; 2037 clear_has_async_exception(); 2038 } 2039 } 2040 2041 if (check_unsafe_error && 2042 condition == _async_unsafe_access_error && !has_pending_exception()) { 2043 condition = _no_async_condition; // done 2044 switch (thread_state()) { 2045 case _thread_in_vm: { 2046 JavaThread* THREAD = this; 2047 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2048 } 2049 case _thread_in_native: { 2050 ThreadInVMfromNative tiv(this); 2051 JavaThread* THREAD = this; 2052 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2053 } 2054 case _thread_in_Java: { 2055 ThreadInVMfromJava tiv(this); 2056 JavaThread* THREAD = this; 2057 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2058 } 2059 default: 2060 ShouldNotReachHere(); 2061 } 2062 } 2063 2064 assert(condition == _no_async_condition || has_pending_exception() || 2065 (!check_unsafe_error && condition == _async_unsafe_access_error), 2066 "must have handled the async condition, if no exception"); 2067 } 2068 2069 void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2070 // 2071 // Check for pending external suspend. Internal suspend requests do 2072 // not use handle_special_runtime_exit_condition(). 2073 // If JNIEnv proxies are allowed, don't self-suspend if the target 2074 // thread is not the current thread. In older versions of jdbx, jdbx 2075 // threads could call into the VM with another thread's JNIEnv so we 2076 // can be here operating on behalf of a suspended thread (4432884). 2077 bool do_self_suspend = is_external_suspend_with_lock(); 2078 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2079 // 2080 // Because thread is external suspended the safepoint code will count 2081 // thread as at a safepoint. This can be odd because we can be here 2082 // as _thread_in_Java which would normally transition to _thread_blocked 2083 // at a safepoint. We would like to mark the thread as _thread_blocked 2084 // before calling java_suspend_self like all other callers of it but 2085 // we must then observe proper safepoint protocol. (We can't leave 2086 // _thread_blocked with a safepoint in progress). However we can be 2087 // here as _thread_in_native_trans so we can't use a normal transition 2088 // constructor/destructor pair because they assert on that type of 2089 // transition. We could do something like: 2090 // 2091 // JavaThreadState state = thread_state(); 2092 // set_thread_state(_thread_in_vm); 2093 // { 2094 // ThreadBlockInVM tbivm(this); 2095 // java_suspend_self() 2096 // } 2097 // set_thread_state(_thread_in_vm_trans); 2098 // if (safepoint) block; 2099 // set_thread_state(state); 2100 // 2101 // but that is pretty messy. Instead we just go with the way the 2102 // code has worked before and note that this is the only path to 2103 // java_suspend_self that doesn't put the thread in _thread_blocked 2104 // mode. 2105 2106 frame_anchor()->make_walkable(this); 2107 java_suspend_self(); 2108 2109 // We might be here for reasons in addition to the self-suspend request 2110 // so check for other async requests. 2111 } 2112 2113 if (check_asyncs) { 2114 check_and_handle_async_exceptions(); 2115 } 2116 } 2117 2118 void JavaThread::send_thread_stop(oop java_throwable) { 2119 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2120 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2121 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2122 2123 // Do not throw asynchronous exceptions against the compiler thread 2124 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2125 if (is_Compiler_thread()) return; 2126 2127 { 2128 // Actually throw the Throwable against the target Thread - however 2129 // only if there is no thread death exception installed already. 2130 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2131 // If the topmost frame is a runtime stub, then we are calling into 2132 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2133 // must deoptimize the caller before continuing, as the compiled exception handler table 2134 // may not be valid 2135 if (has_last_Java_frame()) { 2136 frame f = last_frame(); 2137 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2138 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2139 RegisterMap reg_map(this, UseBiasedLocking); 2140 frame compiled_frame = f.sender(®_map); 2141 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2142 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2143 } 2144 } 2145 } 2146 2147 // Set async. pending exception in thread. 2148 set_pending_async_exception(java_throwable); 2149 2150 if (TraceExceptions) { 2151 ResourceMark rm; 2152 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2153 } 2154 // for AbortVMOnException flag 2155 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2156 } 2157 } 2158 2159 2160 // Interrupt thread so it will wake up from a potential wait() 2161 Thread::interrupt(this); 2162 } 2163 2164 // External suspension mechanism. 2165 // 2166 // Tell the VM to suspend a thread when ever it knows that it does not hold on 2167 // to any VM_locks and it is at a transition 2168 // Self-suspension will happen on the transition out of the vm. 2169 // Catch "this" coming in from JNIEnv pointers when the thread has been freed 2170 // 2171 // Guarantees on return: 2172 // + Target thread will not execute any new bytecode (that's why we need to 2173 // force a safepoint) 2174 // + Target thread will not enter any new monitors 2175 // 2176 void JavaThread::java_suspend() { 2177 { MutexLocker mu(Threads_lock); 2178 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2179 return; 2180 } 2181 } 2182 2183 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2184 if (!is_external_suspend()) { 2185 // a racing resume has cancelled us; bail out now 2186 return; 2187 } 2188 2189 // suspend is done 2190 uint32_t debug_bits = 0; 2191 // Warning: is_ext_suspend_completed() may temporarily drop the 2192 // SR_lock to allow the thread to reach a stable thread state if 2193 // it is currently in a transient thread state. 2194 if (is_ext_suspend_completed(false /* !called_by_wait */, 2195 SuspendRetryDelay, &debug_bits)) { 2196 return; 2197 } 2198 } 2199 2200 VM_ForceSafepoint vm_suspend; 2201 VMThread::execute(&vm_suspend); 2202 } 2203 2204 // Part II of external suspension. 2205 // A JavaThread self suspends when it detects a pending external suspend 2206 // request. This is usually on transitions. It is also done in places 2207 // where continuing to the next transition would surprise the caller, 2208 // e.g., monitor entry. 2209 // 2210 // Returns the number of times that the thread self-suspended. 2211 // 2212 // Note: DO NOT call java_suspend_self() when you just want to block current 2213 // thread. java_suspend_self() is the second stage of cooperative 2214 // suspension for external suspend requests and should only be used 2215 // to complete an external suspend request. 2216 // 2217 int JavaThread::java_suspend_self() { 2218 int ret = 0; 2219 2220 // we are in the process of exiting so don't suspend 2221 if (is_exiting()) { 2222 clear_external_suspend(); 2223 return ret; 2224 } 2225 2226 assert(_anchor.walkable() || 2227 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2228 "must have walkable stack"); 2229 2230 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2231 2232 assert(!this->is_ext_suspended(), 2233 "a thread trying to self-suspend should not already be suspended"); 2234 2235 if (this->is_suspend_equivalent()) { 2236 // If we are self-suspending as a result of the lifting of a 2237 // suspend equivalent condition, then the suspend_equivalent 2238 // flag is not cleared until we set the ext_suspended flag so 2239 // that wait_for_ext_suspend_completion() returns consistent 2240 // results. 2241 this->clear_suspend_equivalent(); 2242 } 2243 2244 // A racing resume may have cancelled us before we grabbed SR_lock 2245 // above. Or another external suspend request could be waiting for us 2246 // by the time we return from SR_lock()->wait(). The thread 2247 // that requested the suspension may already be trying to walk our 2248 // stack and if we return now, we can change the stack out from under 2249 // it. This would be a "bad thing (TM)" and cause the stack walker 2250 // to crash. We stay self-suspended until there are no more pending 2251 // external suspend requests. 2252 while (is_external_suspend()) { 2253 ret++; 2254 this->set_ext_suspended(); 2255 2256 // _ext_suspended flag is cleared by java_resume() 2257 while (is_ext_suspended()) { 2258 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2259 } 2260 } 2261 2262 return ret; 2263 } 2264 2265 #ifdef ASSERT 2266 // verify the JavaThread has not yet been published in the Threads::list, and 2267 // hence doesn't need protection from concurrent access at this stage 2268 void JavaThread::verify_not_published() { 2269 if (!Threads_lock->owned_by_self()) { 2270 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2271 assert(!Threads::includes(this), 2272 "java thread shouldn't have been published yet!"); 2273 } else { 2274 assert(!Threads::includes(this), 2275 "java thread shouldn't have been published yet!"); 2276 } 2277 } 2278 #endif 2279 2280 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2281 // progress or when _suspend_flags is non-zero. 2282 // Current thread needs to self-suspend if there is a suspend request and/or 2283 // block if a safepoint is in progress. 2284 // Async exception ISN'T checked. 2285 // Note only the ThreadInVMfromNative transition can call this function 2286 // directly and when thread state is _thread_in_native_trans 2287 void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2288 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2289 2290 JavaThread *curJT = JavaThread::current(); 2291 bool do_self_suspend = thread->is_external_suspend(); 2292 2293 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2294 2295 // If JNIEnv proxies are allowed, don't self-suspend if the target 2296 // thread is not the current thread. In older versions of jdbx, jdbx 2297 // threads could call into the VM with another thread's JNIEnv so we 2298 // can be here operating on behalf of a suspended thread (4432884). 2299 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2300 JavaThreadState state = thread->thread_state(); 2301 2302 // We mark this thread_blocked state as a suspend-equivalent so 2303 // that a caller to is_ext_suspend_completed() won't be confused. 2304 // The suspend-equivalent state is cleared by java_suspend_self(). 2305 thread->set_suspend_equivalent(); 2306 2307 // If the safepoint code sees the _thread_in_native_trans state, it will 2308 // wait until the thread changes to other thread state. There is no 2309 // guarantee on how soon we can obtain the SR_lock and complete the 2310 // self-suspend request. It would be a bad idea to let safepoint wait for 2311 // too long. Temporarily change the state to _thread_blocked to 2312 // let the VM thread know that this thread is ready for GC. The problem 2313 // of changing thread state is that safepoint could happen just after 2314 // java_suspend_self() returns after being resumed, and VM thread will 2315 // see the _thread_blocked state. We must check for safepoint 2316 // after restoring the state and make sure we won't leave while a safepoint 2317 // is in progress. 2318 thread->set_thread_state(_thread_blocked); 2319 thread->java_suspend_self(); 2320 thread->set_thread_state(state); 2321 // Make sure new state is seen by VM thread 2322 if (os::is_MP()) { 2323 if (UseMembar) { 2324 // Force a fence between the write above and read below 2325 OrderAccess::fence(); 2326 } else { 2327 // Must use this rather than serialization page in particular on Windows 2328 InterfaceSupport::serialize_memory(thread); 2329 } 2330 } 2331 } 2332 2333 if (SafepointSynchronize::do_call_back()) { 2334 // If we are safepointing, then block the caller which may not be 2335 // the same as the target thread (see above). 2336 SafepointSynchronize::block(curJT); 2337 } 2338 2339 if (thread->is_deopt_suspend()) { 2340 thread->clear_deopt_suspend(); 2341 RegisterMap map(thread, false); 2342 frame f = thread->last_frame(); 2343 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2344 f = f.sender(&map); 2345 } 2346 if (f.id() == thread->must_deopt_id()) { 2347 thread->clear_must_deopt_id(); 2348 f.deoptimize(thread); 2349 } else { 2350 fatal("missed deoptimization!"); 2351 } 2352 } 2353 } 2354 2355 // Slow path when the native==>VM/Java barriers detect a safepoint is in 2356 // progress or when _suspend_flags is non-zero. 2357 // Current thread needs to self-suspend if there is a suspend request and/or 2358 // block if a safepoint is in progress. 2359 // Also check for pending async exception (not including unsafe access error). 2360 // Note only the native==>VM/Java barriers can call this function and when 2361 // thread state is _thread_in_native_trans. 2362 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2363 check_safepoint_and_suspend_for_native_trans(thread); 2364 2365 if (thread->has_async_exception()) { 2366 // We are in _thread_in_native_trans state, don't handle unsafe 2367 // access error since that may block. 2368 thread->check_and_handle_async_exceptions(false); 2369 } 2370 } 2371 2372 // This is a variant of the normal 2373 // check_special_condition_for_native_trans with slightly different 2374 // semantics for use by critical native wrappers. It does all the 2375 // normal checks but also performs the transition back into 2376 // thread_in_Java state. This is required so that critical natives 2377 // can potentially block and perform a GC if they are the last thread 2378 // exiting the GC_locker. 2379 void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2380 check_special_condition_for_native_trans(thread); 2381 2382 // Finish the transition 2383 thread->set_thread_state(_thread_in_Java); 2384 2385 if (thread->do_critical_native_unlock()) { 2386 ThreadInVMfromJavaNoAsyncException tiv(thread); 2387 GC_locker::unlock_critical(thread); 2388 thread->clear_critical_native_unlock(); 2389 } 2390 } 2391 2392 // We need to guarantee the Threads_lock here, since resumes are not 2393 // allowed during safepoint synchronization 2394 // Can only resume from an external suspension 2395 void JavaThread::java_resume() { 2396 assert_locked_or_safepoint(Threads_lock); 2397 2398 // Sanity check: thread is gone, has started exiting or the thread 2399 // was not externally suspended. 2400 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2401 return; 2402 } 2403 2404 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2405 2406 clear_external_suspend(); 2407 2408 if (is_ext_suspended()) { 2409 clear_ext_suspended(); 2410 SR_lock()->notify_all(); 2411 } 2412 } 2413 2414 void JavaThread::create_stack_guard_pages() { 2415 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2416 address low_addr = stack_base() - stack_size(); 2417 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2418 2419 int allocate = os::allocate_stack_guard_pages(); 2420 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2421 2422 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2423 warning("Attempt to allocate stack guard pages failed."); 2424 return; 2425 } 2426 2427 if (os::guard_memory((char *) low_addr, len)) { 2428 _stack_guard_state = stack_guard_enabled; 2429 } else { 2430 warning("Attempt to protect stack guard pages failed."); 2431 if (os::uncommit_memory((char *) low_addr, len)) { 2432 warning("Attempt to deallocate stack guard pages failed."); 2433 } 2434 } 2435 } 2436 2437 void JavaThread::remove_stack_guard_pages() { 2438 assert(Thread::current() == this, "from different thread"); 2439 if (_stack_guard_state == stack_guard_unused) return; 2440 address low_addr = stack_base() - stack_size(); 2441 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2442 2443 if (os::allocate_stack_guard_pages()) { 2444 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2445 _stack_guard_state = stack_guard_unused; 2446 } else { 2447 warning("Attempt to deallocate stack guard pages failed."); 2448 } 2449 } else { 2450 if (_stack_guard_state == stack_guard_unused) return; 2451 if (os::unguard_memory((char *) low_addr, len)) { 2452 _stack_guard_state = stack_guard_unused; 2453 } else { 2454 warning("Attempt to unprotect stack guard pages failed."); 2455 } 2456 } 2457 } 2458 2459 void JavaThread::enable_stack_yellow_zone() { 2460 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2461 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2462 2463 // The base notation is from the stacks point of view, growing downward. 2464 // We need to adjust it to work correctly with guard_memory() 2465 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2466 2467 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2468 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2469 2470 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2471 _stack_guard_state = stack_guard_enabled; 2472 } else { 2473 warning("Attempt to guard stack yellow zone failed."); 2474 } 2475 enable_register_stack_guard(); 2476 } 2477 2478 void JavaThread::disable_stack_yellow_zone() { 2479 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2480 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2481 2482 // Simply return if called for a thread that does not use guard pages. 2483 if (_stack_guard_state == stack_guard_unused) return; 2484 2485 // The base notation is from the stacks point of view, growing downward. 2486 // We need to adjust it to work correctly with guard_memory() 2487 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2488 2489 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2490 _stack_guard_state = stack_guard_yellow_disabled; 2491 } else { 2492 warning("Attempt to unguard stack yellow zone failed."); 2493 } 2494 disable_register_stack_guard(); 2495 } 2496 2497 void JavaThread::enable_stack_red_zone() { 2498 // The base notation is from the stacks point of view, growing downward. 2499 // We need to adjust it to work correctly with guard_memory() 2500 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2501 address base = stack_red_zone_base() - stack_red_zone_size(); 2502 2503 guarantee(base < stack_base(), "Error calculating stack red zone"); 2504 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2505 2506 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2507 warning("Attempt to guard stack red zone failed."); 2508 } 2509 } 2510 2511 void JavaThread::disable_stack_red_zone() { 2512 // The base notation is from the stacks point of view, growing downward. 2513 // We need to adjust it to work correctly with guard_memory() 2514 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2515 address base = stack_red_zone_base() - stack_red_zone_size(); 2516 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2517 warning("Attempt to unguard stack red zone failed."); 2518 } 2519 } 2520 2521 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2522 // ignore is there is no stack 2523 if (!has_last_Java_frame()) return; 2524 // traverse the stack frames. Starts from top frame. 2525 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2526 frame* fr = fst.current(); 2527 f(fr, fst.register_map()); 2528 } 2529 } 2530 2531 2532 #ifndef PRODUCT 2533 // Deoptimization 2534 // Function for testing deoptimization 2535 void JavaThread::deoptimize() { 2536 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2537 StackFrameStream fst(this, UseBiasedLocking); 2538 bool deopt = false; // Dump stack only if a deopt actually happens. 2539 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2540 // Iterate over all frames in the thread and deoptimize 2541 for (; !fst.is_done(); fst.next()) { 2542 if (fst.current()->can_be_deoptimized()) { 2543 2544 if (only_at) { 2545 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2546 // consists of comma or carriage return separated numbers so 2547 // search for the current bci in that string. 2548 address pc = fst.current()->pc(); 2549 nmethod* nm = (nmethod*) fst.current()->cb(); 2550 ScopeDesc* sd = nm->scope_desc_at(pc); 2551 char buffer[8]; 2552 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2553 size_t len = strlen(buffer); 2554 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2555 while (found != NULL) { 2556 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2557 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2558 // Check that the bci found is bracketed by terminators. 2559 break; 2560 } 2561 found = strstr(found + 1, buffer); 2562 } 2563 if (!found) { 2564 continue; 2565 } 2566 } 2567 2568 if (DebugDeoptimization && !deopt) { 2569 deopt = true; // One-time only print before deopt 2570 tty->print_cr("[BEFORE Deoptimization]"); 2571 trace_frames(); 2572 trace_stack(); 2573 } 2574 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2575 } 2576 } 2577 2578 if (DebugDeoptimization && deopt) { 2579 tty->print_cr("[AFTER Deoptimization]"); 2580 trace_frames(); 2581 } 2582 } 2583 2584 2585 // Make zombies 2586 void JavaThread::make_zombies() { 2587 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2588 if (fst.current()->can_be_deoptimized()) { 2589 // it is a Java nmethod 2590 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2591 nm->make_not_entrant(); 2592 } 2593 } 2594 } 2595 #endif // PRODUCT 2596 2597 2598 void JavaThread::deoptimized_wrt_marked_nmethods() { 2599 if (!has_last_Java_frame()) return; 2600 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2601 StackFrameStream fst(this, UseBiasedLocking); 2602 for (; !fst.is_done(); fst.next()) { 2603 if (fst.current()->should_be_deoptimized()) { 2604 if (LogCompilation && xtty != NULL) { 2605 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2606 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2607 this->name(), nm != NULL ? nm->compile_id() : -1); 2608 } 2609 2610 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2611 } 2612 } 2613 } 2614 2615 2616 // If the caller is a NamedThread, then remember, in the current scope, 2617 // the given JavaThread in its _processed_thread field. 2618 class RememberProcessedThread: public StackObj { 2619 NamedThread* _cur_thr; 2620 public: 2621 RememberProcessedThread(JavaThread* jthr) { 2622 Thread* thread = Thread::current(); 2623 if (thread->is_Named_thread()) { 2624 _cur_thr = (NamedThread *)thread; 2625 _cur_thr->set_processed_thread(jthr); 2626 } else { 2627 _cur_thr = NULL; 2628 } 2629 } 2630 2631 ~RememberProcessedThread() { 2632 if (_cur_thr) { 2633 _cur_thr->set_processed_thread(NULL); 2634 } 2635 } 2636 }; 2637 2638 void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2639 // Verify that the deferred card marks have been flushed. 2640 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2641 2642 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2643 // since there may be more than one thread using each ThreadProfiler. 2644 2645 // Traverse the GCHandles 2646 Thread::oops_do(f, cld_f, cf); 2647 2648 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2649 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2650 2651 if (has_last_Java_frame()) { 2652 // Record JavaThread to GC thread 2653 RememberProcessedThread rpt(this); 2654 2655 // Traverse the privileged stack 2656 if (_privileged_stack_top != NULL) { 2657 _privileged_stack_top->oops_do(f); 2658 } 2659 2660 // traverse the registered growable array 2661 if (_array_for_gc != NULL) { 2662 for (int index = 0; index < _array_for_gc->length(); index++) { 2663 f->do_oop(_array_for_gc->adr_at(index)); 2664 } 2665 } 2666 2667 // Traverse the monitor chunks 2668 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2669 chunk->oops_do(f); 2670 } 2671 2672 // Traverse the execution stack 2673 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2674 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2675 } 2676 } 2677 2678 // callee_target is never live across a gc point so NULL it here should 2679 // it still contain a methdOop. 2680 2681 set_callee_target(NULL); 2682 2683 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2684 // If we have deferred set_locals there might be oops waiting to be 2685 // written 2686 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2687 if (list != NULL) { 2688 for (int i = 0; i < list->length(); i++) { 2689 list->at(i)->oops_do(f); 2690 } 2691 } 2692 2693 // Traverse instance variables at the end since the GC may be moving things 2694 // around using this function 2695 f->do_oop((oop*) &_threadObj); 2696 f->do_oop((oop*) &_vm_result); 2697 f->do_oop((oop*) &_exception_oop); 2698 f->do_oop((oop*) &_pending_async_exception); 2699 2700 if (jvmti_thread_state() != NULL) { 2701 jvmti_thread_state()->oops_do(f); 2702 } 2703 } 2704 2705 void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2706 Thread::nmethods_do(cf); // (super method is a no-op) 2707 2708 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2709 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2710 2711 if (has_last_Java_frame()) { 2712 // Traverse the execution stack 2713 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2714 fst.current()->nmethods_do(cf); 2715 } 2716 } 2717 } 2718 2719 void JavaThread::metadata_do(void f(Metadata*)) { 2720 if (has_last_Java_frame()) { 2721 // Traverse the execution stack to call f() on the methods in the stack 2722 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2723 fst.current()->metadata_do(f); 2724 } 2725 } else if (is_Compiler_thread()) { 2726 // need to walk ciMetadata in current compile tasks to keep alive. 2727 CompilerThread* ct = (CompilerThread*)this; 2728 if (ct->env() != NULL) { 2729 ct->env()->metadata_do(f); 2730 } 2731 } 2732 } 2733 2734 // Printing 2735 const char* _get_thread_state_name(JavaThreadState _thread_state) { 2736 switch (_thread_state) { 2737 case _thread_uninitialized: return "_thread_uninitialized"; 2738 case _thread_new: return "_thread_new"; 2739 case _thread_new_trans: return "_thread_new_trans"; 2740 case _thread_in_native: return "_thread_in_native"; 2741 case _thread_in_native_trans: return "_thread_in_native_trans"; 2742 case _thread_in_vm: return "_thread_in_vm"; 2743 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2744 case _thread_in_Java: return "_thread_in_Java"; 2745 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2746 case _thread_blocked: return "_thread_blocked"; 2747 case _thread_blocked_trans: return "_thread_blocked_trans"; 2748 default: return "unknown thread state"; 2749 } 2750 } 2751 2752 #ifndef PRODUCT 2753 void JavaThread::print_thread_state_on(outputStream *st) const { 2754 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2755 }; 2756 void JavaThread::print_thread_state() const { 2757 print_thread_state_on(tty); 2758 } 2759 #endif // PRODUCT 2760 2761 // Called by Threads::print() for VM_PrintThreads operation 2762 void JavaThread::print_on(outputStream *st) const { 2763 st->print("\"%s\" ", get_thread_name()); 2764 oop thread_oop = threadObj(); 2765 if (thread_oop != NULL) { 2766 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2767 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2768 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2769 } 2770 Thread::print_on(st); 2771 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2772 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2773 if (thread_oop != NULL) { 2774 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2775 } 2776 #ifndef PRODUCT 2777 print_thread_state_on(st); 2778 _safepoint_state->print_on(st); 2779 #endif // PRODUCT 2780 } 2781 2782 // Called by fatal error handler. The difference between this and 2783 // JavaThread::print() is that we can't grab lock or allocate memory. 2784 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2785 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2786 oop thread_obj = threadObj(); 2787 if (thread_obj != NULL) { 2788 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2789 } 2790 st->print(" ["); 2791 st->print("%s", _get_thread_state_name(_thread_state)); 2792 if (osthread()) { 2793 st->print(", id=%d", osthread()->thread_id()); 2794 } 2795 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2796 _stack_base - _stack_size, _stack_base); 2797 st->print("]"); 2798 return; 2799 } 2800 2801 // Verification 2802 2803 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2804 2805 void JavaThread::verify() { 2806 // Verify oops in the thread. 2807 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2808 2809 // Verify the stack frames. 2810 frames_do(frame_verify); 2811 } 2812 2813 // CR 6300358 (sub-CR 2137150) 2814 // Most callers of this method assume that it can't return NULL but a 2815 // thread may not have a name whilst it is in the process of attaching to 2816 // the VM - see CR 6412693, and there are places where a JavaThread can be 2817 // seen prior to having it's threadObj set (eg JNI attaching threads and 2818 // if vm exit occurs during initialization). These cases can all be accounted 2819 // for such that this method never returns NULL. 2820 const char* JavaThread::get_thread_name() const { 2821 #ifdef ASSERT 2822 // early safepoints can hit while current thread does not yet have TLS 2823 if (!SafepointSynchronize::is_at_safepoint()) { 2824 Thread *cur = Thread::current(); 2825 if (!(cur->is_Java_thread() && cur == this)) { 2826 // Current JavaThreads are allowed to get their own name without 2827 // the Threads_lock. 2828 assert_locked_or_safepoint(Threads_lock); 2829 } 2830 } 2831 #endif // ASSERT 2832 return get_thread_name_string(); 2833 } 2834 2835 // Returns a non-NULL representation of this thread's name, or a suitable 2836 // descriptive string if there is no set name 2837 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2838 const char* name_str; 2839 oop thread_obj = threadObj(); 2840 if (thread_obj != NULL) { 2841 oop name = java_lang_Thread::name(thread_obj); 2842 if (name != NULL) { 2843 if (buf == NULL) { 2844 name_str = java_lang_String::as_utf8_string(name); 2845 } else { 2846 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 2847 } 2848 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2849 name_str = "<no-name - thread is attaching>"; 2850 } else { 2851 name_str = Thread::name(); 2852 } 2853 } else { 2854 name_str = Thread::name(); 2855 } 2856 assert(name_str != NULL, "unexpected NULL thread name"); 2857 return name_str; 2858 } 2859 2860 2861 const char* JavaThread::get_threadgroup_name() const { 2862 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2863 oop thread_obj = threadObj(); 2864 if (thread_obj != NULL) { 2865 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2866 if (thread_group != NULL) { 2867 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2868 // ThreadGroup.name can be null 2869 if (name != NULL) { 2870 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2871 return str; 2872 } 2873 } 2874 } 2875 return NULL; 2876 } 2877 2878 const char* JavaThread::get_parent_name() const { 2879 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2880 oop thread_obj = threadObj(); 2881 if (thread_obj != NULL) { 2882 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2883 if (thread_group != NULL) { 2884 oop parent = java_lang_ThreadGroup::parent(thread_group); 2885 if (parent != NULL) { 2886 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2887 // ThreadGroup.name can be null 2888 if (name != NULL) { 2889 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2890 return str; 2891 } 2892 } 2893 } 2894 } 2895 return NULL; 2896 } 2897 2898 ThreadPriority JavaThread::java_priority() const { 2899 oop thr_oop = threadObj(); 2900 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2901 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2902 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2903 return priority; 2904 } 2905 2906 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2907 2908 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2909 // Link Java Thread object <-> C++ Thread 2910 2911 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2912 // and put it into a new Handle. The Handle "thread_oop" can then 2913 // be used to pass the C++ thread object to other methods. 2914 2915 // Set the Java level thread object (jthread) field of the 2916 // new thread (a JavaThread *) to C++ thread object using the 2917 // "thread_oop" handle. 2918 2919 // Set the thread field (a JavaThread *) of the 2920 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2921 2922 Handle thread_oop(Thread::current(), 2923 JNIHandles::resolve_non_null(jni_thread)); 2924 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 2925 "must be initialized"); 2926 set_threadObj(thread_oop()); 2927 java_lang_Thread::set_thread(thread_oop(), this); 2928 2929 if (prio == NoPriority) { 2930 prio = java_lang_Thread::priority(thread_oop()); 2931 assert(prio != NoPriority, "A valid priority should be present"); 2932 } 2933 2934 // Push the Java priority down to the native thread; needs Threads_lock 2935 Thread::set_priority(this, prio); 2936 2937 prepare_ext(); 2938 2939 // Add the new thread to the Threads list and set it in motion. 2940 // We must have threads lock in order to call Threads::add. 2941 // It is crucial that we do not block before the thread is 2942 // added to the Threads list for if a GC happens, then the java_thread oop 2943 // will not be visited by GC. 2944 Threads::add(this); 2945 } 2946 2947 oop JavaThread::current_park_blocker() { 2948 // Support for JSR-166 locks 2949 oop thread_oop = threadObj(); 2950 if (thread_oop != NULL && 2951 JDK_Version::current().supports_thread_park_blocker()) { 2952 return java_lang_Thread::park_blocker(thread_oop); 2953 } 2954 return NULL; 2955 } 2956 2957 2958 void JavaThread::print_stack_on(outputStream* st) { 2959 if (!has_last_Java_frame()) return; 2960 ResourceMark rm; 2961 HandleMark hm; 2962 2963 RegisterMap reg_map(this); 2964 vframe* start_vf = last_java_vframe(®_map); 2965 int count = 0; 2966 for (vframe* f = start_vf; f; f = f->sender()) { 2967 if (f->is_java_frame()) { 2968 javaVFrame* jvf = javaVFrame::cast(f); 2969 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 2970 2971 // Print out lock information 2972 if (JavaMonitorsInStackTrace) { 2973 jvf->print_lock_info_on(st, count); 2974 } 2975 } else { 2976 // Ignore non-Java frames 2977 } 2978 2979 // Bail-out case for too deep stacks 2980 count++; 2981 if (MaxJavaStackTraceDepth == count) return; 2982 } 2983 } 2984 2985 2986 // JVMTI PopFrame support 2987 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 2988 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 2989 if (in_bytes(size_in_bytes) != 0) { 2990 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 2991 _popframe_preserved_args_size = in_bytes(size_in_bytes); 2992 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 2993 } 2994 } 2995 2996 void* JavaThread::popframe_preserved_args() { 2997 return _popframe_preserved_args; 2998 } 2999 3000 ByteSize JavaThread::popframe_preserved_args_size() { 3001 return in_ByteSize(_popframe_preserved_args_size); 3002 } 3003 3004 WordSize JavaThread::popframe_preserved_args_size_in_words() { 3005 int sz = in_bytes(popframe_preserved_args_size()); 3006 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3007 return in_WordSize(sz / wordSize); 3008 } 3009 3010 void JavaThread::popframe_free_preserved_args() { 3011 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3012 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3013 _popframe_preserved_args = NULL; 3014 _popframe_preserved_args_size = 0; 3015 } 3016 3017 #ifndef PRODUCT 3018 3019 void JavaThread::trace_frames() { 3020 tty->print_cr("[Describe stack]"); 3021 int frame_no = 1; 3022 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3023 tty->print(" %d. ", frame_no++); 3024 fst.current()->print_value_on(tty, this); 3025 tty->cr(); 3026 } 3027 } 3028 3029 class PrintAndVerifyOopClosure: public OopClosure { 3030 protected: 3031 template <class T> inline void do_oop_work(T* p) { 3032 oop obj = oopDesc::load_decode_heap_oop(p); 3033 if (obj == NULL) return; 3034 tty->print(INTPTR_FORMAT ": ", p); 3035 if (obj->is_oop_or_null()) { 3036 if (obj->is_objArray()) { 3037 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3038 } else { 3039 obj->print(); 3040 } 3041 } else { 3042 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3043 } 3044 tty->cr(); 3045 } 3046 public: 3047 virtual void do_oop(oop* p) { do_oop_work(p); } 3048 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3049 }; 3050 3051 3052 static void oops_print(frame* f, const RegisterMap *map) { 3053 PrintAndVerifyOopClosure print; 3054 f->print_value(); 3055 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3056 } 3057 3058 // Print our all the locations that contain oops and whether they are 3059 // valid or not. This useful when trying to find the oldest frame 3060 // where an oop has gone bad since the frame walk is from youngest to 3061 // oldest. 3062 void JavaThread::trace_oops() { 3063 tty->print_cr("[Trace oops]"); 3064 frames_do(oops_print); 3065 } 3066 3067 3068 #ifdef ASSERT 3069 // Print or validate the layout of stack frames 3070 void JavaThread::print_frame_layout(int depth, bool validate_only) { 3071 ResourceMark rm; 3072 PRESERVE_EXCEPTION_MARK; 3073 FrameValues values; 3074 int frame_no = 0; 3075 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3076 fst.current()->describe(values, ++frame_no); 3077 if (depth == frame_no) break; 3078 } 3079 if (validate_only) { 3080 values.validate(); 3081 } else { 3082 tty->print_cr("[Describe stack layout]"); 3083 values.print(this); 3084 } 3085 } 3086 #endif 3087 3088 void JavaThread::trace_stack_from(vframe* start_vf) { 3089 ResourceMark rm; 3090 int vframe_no = 1; 3091 for (vframe* f = start_vf; f; f = f->sender()) { 3092 if (f->is_java_frame()) { 3093 javaVFrame::cast(f)->print_activation(vframe_no++); 3094 } else { 3095 f->print(); 3096 } 3097 if (vframe_no > StackPrintLimit) { 3098 tty->print_cr("...<more frames>..."); 3099 return; 3100 } 3101 } 3102 } 3103 3104 3105 void JavaThread::trace_stack() { 3106 if (!has_last_Java_frame()) return; 3107 ResourceMark rm; 3108 HandleMark hm; 3109 RegisterMap reg_map(this); 3110 trace_stack_from(last_java_vframe(®_map)); 3111 } 3112 3113 3114 #endif // PRODUCT 3115 3116 3117 javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3118 assert(reg_map != NULL, "a map must be given"); 3119 frame f = last_frame(); 3120 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3121 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3122 } 3123 return NULL; 3124 } 3125 3126 3127 Klass* JavaThread::security_get_caller_class(int depth) { 3128 vframeStream vfst(this); 3129 vfst.security_get_caller_frame(depth); 3130 if (!vfst.at_end()) { 3131 return vfst.method()->method_holder(); 3132 } 3133 return NULL; 3134 } 3135 3136 static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3137 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3138 CompileBroker::compiler_thread_loop(); 3139 } 3140 3141 static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3142 NMethodSweeper::sweeper_loop(); 3143 } 3144 3145 // Create a CompilerThread 3146 CompilerThread::CompilerThread(CompileQueue* queue, 3147 CompilerCounters* counters) 3148 : JavaThread(&compiler_thread_entry) { 3149 _env = NULL; 3150 _log = NULL; 3151 _task = NULL; 3152 _queue = queue; 3153 _counters = counters; 3154 _buffer_blob = NULL; 3155 _compiler = NULL; 3156 3157 #ifndef PRODUCT 3158 _ideal_graph_printer = NULL; 3159 #endif 3160 } 3161 3162 // Create sweeper thread 3163 CodeCacheSweeperThread::CodeCacheSweeperThread() 3164 : JavaThread(&sweeper_thread_entry) { 3165 _scanned_nmethod = NULL; 3166 } 3167 void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3168 JavaThread::oops_do(f, cld_f, cf); 3169 if (_scanned_nmethod != NULL && cf != NULL) { 3170 // Safepoints can occur when the sweeper is scanning an nmethod so 3171 // process it here to make sure it isn't unloaded in the middle of 3172 // a scan. 3173 cf->do_code_blob(_scanned_nmethod); 3174 } 3175 } 3176 3177 3178 // ======= Threads ======== 3179 3180 // The Threads class links together all active threads, and provides 3181 // operations over all threads. It is protected by its own Mutex 3182 // lock, which is also used in other contexts to protect thread 3183 // operations from having the thread being operated on from exiting 3184 // and going away unexpectedly (e.g., safepoint synchronization) 3185 3186 JavaThread* Threads::_thread_list = NULL; 3187 int Threads::_number_of_threads = 0; 3188 int Threads::_number_of_non_daemon_threads = 0; 3189 int Threads::_return_code = 0; 3190 int Threads::_thread_claim_parity = 0; 3191 size_t JavaThread::_stack_size_at_create = 0; 3192 #ifdef ASSERT 3193 bool Threads::_vm_complete = false; 3194 #endif 3195 3196 // All JavaThreads 3197 #define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3198 3199 // All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3200 void Threads::threads_do(ThreadClosure* tc) { 3201 assert_locked_or_safepoint(Threads_lock); 3202 // ALL_JAVA_THREADS iterates through all JavaThreads 3203 ALL_JAVA_THREADS(p) { 3204 tc->do_thread(p); 3205 } 3206 // Someday we could have a table or list of all non-JavaThreads. 3207 // For now, just manually iterate through them. 3208 tc->do_thread(VMThread::vm_thread()); 3209 Universe::heap()->gc_threads_do(tc); 3210 WatcherThread *wt = WatcherThread::watcher_thread(); 3211 // Strictly speaking, the following NULL check isn't sufficient to make sure 3212 // the data for WatcherThread is still valid upon being examined. However, 3213 // considering that WatchThread terminates when the VM is on the way to 3214 // exit at safepoint, the chance of the above is extremely small. The right 3215 // way to prevent termination of WatcherThread would be to acquire 3216 // Terminator_lock, but we can't do that without violating the lock rank 3217 // checking in some cases. 3218 if (wt != NULL) { 3219 tc->do_thread(wt); 3220 } 3221 3222 // If CompilerThreads ever become non-JavaThreads, add them here 3223 } 3224 3225 void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3226 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3227 3228 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3229 create_vm_init_libraries(); 3230 } 3231 3232 initialize_class(vmSymbols::java_lang_String(), CHECK); 3233 3234 // Initialize java_lang.System (needed before creating the thread) 3235 initialize_class(vmSymbols::java_lang_System(), CHECK); 3236 // The VM creates & returns objects of this class. Make sure it's initialized. 3237 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3238 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3239 Handle thread_group = create_initial_thread_group(CHECK); 3240 Universe::set_main_thread_group(thread_group()); 3241 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3242 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3243 main_thread->set_threadObj(thread_object); 3244 // Set thread status to running since main thread has 3245 // been started and running. 3246 java_lang_Thread::set_thread_status(thread_object, 3247 java_lang_Thread::RUNNABLE); 3248 3249 // The VM preresolves methods to these classes. Make sure that they get initialized 3250 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3251 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3252 call_initializeSystemClass(CHECK); 3253 3254 // get the Java runtime name after java.lang.System is initialized 3255 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3256 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3257 3258 // an instance of OutOfMemory exception has been allocated earlier 3259 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3260 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3261 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3262 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3263 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3264 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3265 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3266 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3267 } 3268 3269 void Threads::initialize_jsr292_core_classes(TRAPS) { 3270 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3271 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3272 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3273 } 3274 3275 jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3276 extern void JDK_Version_init(); 3277 3278 // Preinitialize version info. 3279 VM_Version::early_initialize(); 3280 3281 // Check version 3282 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3283 3284 // Initialize the output stream module 3285 ostream_init(); 3286 3287 // Process java launcher properties. 3288 Arguments::process_sun_java_launcher_properties(args); 3289 3290 // Initialize the os module before using TLS 3291 os::init(); 3292 3293 // Initialize system properties. 3294 Arguments::init_system_properties(); 3295 3296 // So that JDK version can be used as a discriminator when parsing arguments 3297 JDK_Version_init(); 3298 3299 // Update/Initialize System properties after JDK version number is known 3300 Arguments::init_version_specific_system_properties(); 3301 3302 // Parse arguments 3303 jint parse_result = Arguments::parse(args); 3304 if (parse_result != JNI_OK) return parse_result; 3305 3306 os::init_before_ergo(); 3307 3308 jint ergo_result = Arguments::apply_ergo(); 3309 if (ergo_result != JNI_OK) return ergo_result; 3310 3311 // Final check of all arguments after ergonomics which may change values. 3312 if (!CommandLineFlags::check_all_ranges_and_constraints()) { 3313 return JNI_EINVAL; 3314 } 3315 3316 if (PauseAtStartup) { 3317 os::pause(); 3318 } 3319 3320 HOTSPOT_VM_INIT_BEGIN(); 3321 3322 // Record VM creation timing statistics 3323 TraceVmCreationTime create_vm_timer; 3324 create_vm_timer.start(); 3325 3326 // Timing (must come after argument parsing) 3327 TraceTime timer("Create VM", TraceStartupTime); 3328 3329 // Initialize the os module after parsing the args 3330 jint os_init_2_result = os::init_2(); 3331 if (os_init_2_result != JNI_OK) return os_init_2_result; 3332 3333 jint adjust_after_os_result = Arguments::adjust_after_os(); 3334 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3335 3336 // initialize TLS 3337 ThreadLocalStorage::init(); 3338 3339 // Initialize output stream logging 3340 ostream_init_log(); 3341 3342 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3343 // Must be before create_vm_init_agents() 3344 if (Arguments::init_libraries_at_startup()) { 3345 convert_vm_init_libraries_to_agents(); 3346 } 3347 3348 // Launch -agentlib/-agentpath and converted -Xrun agents 3349 if (Arguments::init_agents_at_startup()) { 3350 create_vm_init_agents(); 3351 } 3352 3353 // Initialize Threads state 3354 _thread_list = NULL; 3355 _number_of_threads = 0; 3356 _number_of_non_daemon_threads = 0; 3357 3358 // Initialize global data structures and create system classes in heap 3359 vm_init_globals(); 3360 3361 // Attach the main thread to this os thread 3362 JavaThread* main_thread = new JavaThread(); 3363 main_thread->set_thread_state(_thread_in_vm); 3364 // must do this before set_active_handles and initialize_thread_local_storage 3365 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3366 // change the stack size recorded here to one based on the java thread 3367 // stacksize. This adjusted size is what is used to figure the placement 3368 // of the guard pages. 3369 main_thread->record_stack_base_and_size(); 3370 main_thread->initialize_thread_local_storage(); 3371 3372 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3373 3374 if (!main_thread->set_as_starting_thread()) { 3375 vm_shutdown_during_initialization( 3376 "Failed necessary internal allocation. Out of swap space"); 3377 delete main_thread; 3378 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3379 return JNI_ENOMEM; 3380 } 3381 3382 // Enable guard page *after* os::create_main_thread(), otherwise it would 3383 // crash Linux VM, see notes in os_linux.cpp. 3384 main_thread->create_stack_guard_pages(); 3385 3386 // Initialize Java-Level synchronization subsystem 3387 ObjectMonitor::Initialize(); 3388 3389 // Initialize global modules 3390 jint status = init_globals(); 3391 if (status != JNI_OK) { 3392 delete main_thread; 3393 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3394 return status; 3395 } 3396 3397 // Should be done after the heap is fully created 3398 main_thread->cache_global_variables(); 3399 3400 HandleMark hm; 3401 3402 { MutexLocker mu(Threads_lock); 3403 Threads::add(main_thread); 3404 } 3405 3406 // Any JVMTI raw monitors entered in onload will transition into 3407 // real raw monitor. VM is setup enough here for raw monitor enter. 3408 JvmtiExport::transition_pending_onload_raw_monitors(); 3409 3410 // Create the VMThread 3411 { TraceTime timer("Start VMThread", TraceStartupTime); 3412 VMThread::create(); 3413 Thread* vmthread = VMThread::vm_thread(); 3414 3415 if (!os::create_thread(vmthread, os::vm_thread)) { 3416 vm_exit_during_initialization("Cannot create VM thread. " 3417 "Out of system resources."); 3418 } 3419 3420 // Wait for the VM thread to become ready, and VMThread::run to initialize 3421 // Monitors can have spurious returns, must always check another state flag 3422 { 3423 MutexLocker ml(Notify_lock); 3424 os::start_thread(vmthread); 3425 while (vmthread->active_handles() == NULL) { 3426 Notify_lock->wait(); 3427 } 3428 } 3429 } 3430 3431 assert(Universe::is_fully_initialized(), "not initialized"); 3432 if (VerifyDuringStartup) { 3433 // Make sure we're starting with a clean slate. 3434 VM_Verify verify_op; 3435 VMThread::execute(&verify_op); 3436 } 3437 3438 Thread* THREAD = Thread::current(); 3439 3440 // At this point, the Universe is initialized, but we have not executed 3441 // any byte code. Now is a good time (the only time) to dump out the 3442 // internal state of the JVM for sharing. 3443 if (DumpSharedSpaces) { 3444 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3445 ShouldNotReachHere(); 3446 } 3447 3448 // Always call even when there are not JVMTI environments yet, since environments 3449 // may be attached late and JVMTI must track phases of VM execution 3450 JvmtiExport::enter_start_phase(); 3451 3452 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3453 JvmtiExport::post_vm_start(); 3454 3455 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3456 3457 // We need this for ClassDataSharing - the initial vm.info property is set 3458 // with the default value of CDS "sharing" which may be reset through 3459 // command line options. 3460 reset_vm_info_property(CHECK_JNI_ERR); 3461 3462 quicken_jni_functions(); 3463 3464 // Must be run after init_ft which initializes ft_enabled 3465 if (TRACE_INITIALIZE() != JNI_OK) { 3466 vm_exit_during_initialization("Failed to initialize tracing backend"); 3467 } 3468 3469 // Set flag that basic initialization has completed. Used by exceptions and various 3470 // debug stuff, that does not work until all basic classes have been initialized. 3471 set_init_completed(); 3472 3473 Metaspace::post_initialize(); 3474 3475 HOTSPOT_VM_INIT_END(); 3476 3477 // record VM initialization completion time 3478 #if INCLUDE_MANAGEMENT 3479 Management::record_vm_init_completed(); 3480 #endif // INCLUDE_MANAGEMENT 3481 3482 // Compute system loader. Note that this has to occur after set_init_completed, since 3483 // valid exceptions may be thrown in the process. 3484 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3485 // set_init_completed has just been called, causing exceptions not to be shortcut 3486 // anymore. We call vm_exit_during_initialization directly instead. 3487 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR); 3488 3489 #if INCLUDE_ALL_GCS 3490 // Support for ConcurrentMarkSweep. This should be cleaned up 3491 // and better encapsulated. The ugly nested if test would go away 3492 // once things are properly refactored. XXX YSR 3493 if (UseConcMarkSweepGC || UseG1GC) { 3494 if (UseConcMarkSweepGC) { 3495 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3496 } else { 3497 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3498 } 3499 } 3500 #endif // INCLUDE_ALL_GCS 3501 3502 // Always call even when there are not JVMTI environments yet, since environments 3503 // may be attached late and JVMTI must track phases of VM execution 3504 JvmtiExport::enter_live_phase(); 3505 3506 // Signal Dispatcher needs to be started before VMInit event is posted 3507 os::signal_init(); 3508 3509 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3510 if (!DisableAttachMechanism) { 3511 AttachListener::vm_start(); 3512 if (StartAttachListener || AttachListener::init_at_startup()) { 3513 AttachListener::init(); 3514 } 3515 } 3516 3517 // Launch -Xrun agents 3518 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3519 // back-end can launch with -Xdebug -Xrunjdwp. 3520 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3521 create_vm_init_libraries(); 3522 } 3523 3524 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3525 JvmtiExport::post_vm_initialized(); 3526 3527 if (TRACE_START() != JNI_OK) { 3528 vm_exit_during_initialization("Failed to start tracing backend."); 3529 } 3530 3531 if (CleanChunkPoolAsync) { 3532 Chunk::start_chunk_pool_cleaner_task(); 3533 } 3534 3535 // initialize compiler(s) 3536 #if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3537 CompileBroker::compilation_init(); 3538 #endif 3539 3540 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3541 // It is done after compilers are initialized, because otherwise compilations of 3542 // signature polymorphic MH intrinsics can be missed 3543 // (see SystemDictionary::find_method_handle_intrinsic). 3544 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3545 3546 #if INCLUDE_MANAGEMENT 3547 Management::initialize(THREAD); 3548 3549 if (HAS_PENDING_EXCEPTION) { 3550 // management agent fails to start possibly due to 3551 // configuration problem and is responsible for printing 3552 // stack trace if appropriate. Simply exit VM. 3553 vm_exit(1); 3554 } 3555 #endif // INCLUDE_MANAGEMENT 3556 3557 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3558 if (MemProfiling) MemProfiler::engage(); 3559 StatSampler::engage(); 3560 if (CheckJNICalls) JniPeriodicChecker::engage(); 3561 3562 BiasedLocking::init(); 3563 3564 #if INCLUDE_RTM_OPT 3565 RTMLockingCounters::init(); 3566 #endif 3567 3568 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3569 call_postVMInitHook(THREAD); 3570 // The Java side of PostVMInitHook.run must deal with all 3571 // exceptions and provide means of diagnosis. 3572 if (HAS_PENDING_EXCEPTION) { 3573 CLEAR_PENDING_EXCEPTION; 3574 } 3575 } 3576 3577 { 3578 MutexLocker ml(PeriodicTask_lock); 3579 // Make sure the WatcherThread can be started by WatcherThread::start() 3580 // or by dynamic enrollment. 3581 WatcherThread::make_startable(); 3582 // Start up the WatcherThread if there are any periodic tasks 3583 // NOTE: All PeriodicTasks should be registered by now. If they 3584 // aren't, late joiners might appear to start slowly (we might 3585 // take a while to process their first tick). 3586 if (PeriodicTask::num_tasks() > 0) { 3587 WatcherThread::start(); 3588 } 3589 } 3590 3591 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM); 3592 3593 create_vm_timer.end(); 3594 #ifdef ASSERT 3595 _vm_complete = true; 3596 #endif 3597 return JNI_OK; 3598 } 3599 3600 // type for the Agent_OnLoad and JVM_OnLoad entry points 3601 extern "C" { 3602 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3603 } 3604 // Find a command line agent library and return its entry point for 3605 // -agentlib: -agentpath: -Xrun 3606 // num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3607 static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 3608 const char *on_load_symbols[], 3609 size_t num_symbol_entries) { 3610 OnLoadEntry_t on_load_entry = NULL; 3611 void *library = NULL; 3612 3613 if (!agent->valid()) { 3614 char buffer[JVM_MAXPATHLEN]; 3615 char ebuf[1024] = ""; 3616 const char *name = agent->name(); 3617 const char *msg = "Could not find agent library "; 3618 3619 // First check to see if agent is statically linked into executable 3620 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3621 library = agent->os_lib(); 3622 } else if (agent->is_absolute_path()) { 3623 library = os::dll_load(name, ebuf, sizeof ebuf); 3624 if (library == NULL) { 3625 const char *sub_msg = " in absolute path, with error: "; 3626 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3627 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3628 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3629 // If we can't find the agent, exit. 3630 vm_exit_during_initialization(buf, NULL); 3631 FREE_C_HEAP_ARRAY(char, buf); 3632 } 3633 } else { 3634 // Try to load the agent from the standard dll directory 3635 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3636 name)) { 3637 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3638 } 3639 if (library == NULL) { // Try the local directory 3640 char ns[1] = {0}; 3641 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3642 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3643 } 3644 if (library == NULL) { 3645 const char *sub_msg = " on the library path, with error: "; 3646 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3647 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3648 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3649 // If we can't find the agent, exit. 3650 vm_exit_during_initialization(buf, NULL); 3651 FREE_C_HEAP_ARRAY(char, buf); 3652 } 3653 } 3654 } 3655 agent->set_os_lib(library); 3656 agent->set_valid(); 3657 } 3658 3659 // Find the OnLoad function. 3660 on_load_entry = 3661 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3662 false, 3663 on_load_symbols, 3664 num_symbol_entries)); 3665 return on_load_entry; 3666 } 3667 3668 // Find the JVM_OnLoad entry point 3669 static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3670 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3671 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3672 } 3673 3674 // Find the Agent_OnLoad entry point 3675 static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3676 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3677 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3678 } 3679 3680 // For backwards compatibility with -Xrun 3681 // Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3682 // treated like -agentpath: 3683 // Must be called before agent libraries are created 3684 void Threads::convert_vm_init_libraries_to_agents() { 3685 AgentLibrary* agent; 3686 AgentLibrary* next; 3687 3688 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3689 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3690 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3691 3692 // If there is an JVM_OnLoad function it will get called later, 3693 // otherwise see if there is an Agent_OnLoad 3694 if (on_load_entry == NULL) { 3695 on_load_entry = lookup_agent_on_load(agent); 3696 if (on_load_entry != NULL) { 3697 // switch it to the agent list -- so that Agent_OnLoad will be called, 3698 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3699 Arguments::convert_library_to_agent(agent); 3700 } else { 3701 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3702 } 3703 } 3704 } 3705 } 3706 3707 // Create agents for -agentlib: -agentpath: and converted -Xrun 3708 // Invokes Agent_OnLoad 3709 // Called very early -- before JavaThreads exist 3710 void Threads::create_vm_init_agents() { 3711 extern struct JavaVM_ main_vm; 3712 AgentLibrary* agent; 3713 3714 JvmtiExport::enter_onload_phase(); 3715 3716 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3717 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3718 3719 if (on_load_entry != NULL) { 3720 // Invoke the Agent_OnLoad function 3721 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3722 if (err != JNI_OK) { 3723 vm_exit_during_initialization("agent library failed to init", agent->name()); 3724 } 3725 } else { 3726 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3727 } 3728 } 3729 JvmtiExport::enter_primordial_phase(); 3730 } 3731 3732 extern "C" { 3733 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3734 } 3735 3736 void Threads::shutdown_vm_agents() { 3737 // Send any Agent_OnUnload notifications 3738 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3739 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3740 extern struct JavaVM_ main_vm; 3741 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3742 3743 // Find the Agent_OnUnload function. 3744 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3745 os::find_agent_function(agent, 3746 false, 3747 on_unload_symbols, 3748 num_symbol_entries)); 3749 3750 // Invoke the Agent_OnUnload function 3751 if (unload_entry != NULL) { 3752 JavaThread* thread = JavaThread::current(); 3753 ThreadToNativeFromVM ttn(thread); 3754 HandleMark hm(thread); 3755 (*unload_entry)(&main_vm); 3756 } 3757 } 3758 } 3759 3760 // Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3761 // Invokes JVM_OnLoad 3762 void Threads::create_vm_init_libraries() { 3763 extern struct JavaVM_ main_vm; 3764 AgentLibrary* agent; 3765 3766 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3767 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3768 3769 if (on_load_entry != NULL) { 3770 // Invoke the JVM_OnLoad function 3771 JavaThread* thread = JavaThread::current(); 3772 ThreadToNativeFromVM ttn(thread); 3773 HandleMark hm(thread); 3774 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3775 if (err != JNI_OK) { 3776 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3777 } 3778 } else { 3779 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3780 } 3781 } 3782 } 3783 3784 JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3785 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3786 3787 JavaThread* java_thread = NULL; 3788 // Sequential search for now. Need to do better optimization later. 3789 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3790 oop tobj = thread->threadObj(); 3791 if (!thread->is_exiting() && 3792 tobj != NULL && 3793 java_tid == java_lang_Thread::thread_id(tobj)) { 3794 java_thread = thread; 3795 break; 3796 } 3797 } 3798 return java_thread; 3799 } 3800 3801 3802 // Last thread running calls java.lang.Shutdown.shutdown() 3803 void JavaThread::invoke_shutdown_hooks() { 3804 HandleMark hm(this); 3805 3806 // We could get here with a pending exception, if so clear it now. 3807 if (this->has_pending_exception()) { 3808 this->clear_pending_exception(); 3809 } 3810 3811 EXCEPTION_MARK; 3812 Klass* k = 3813 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3814 THREAD); 3815 if (k != NULL) { 3816 // SystemDictionary::resolve_or_null will return null if there was 3817 // an exception. If we cannot load the Shutdown class, just don't 3818 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3819 // and finalizers (if runFinalizersOnExit is set) won't be run. 3820 // Note that if a shutdown hook was registered or runFinalizersOnExit 3821 // was called, the Shutdown class would have already been loaded 3822 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3823 instanceKlassHandle shutdown_klass (THREAD, k); 3824 JavaValue result(T_VOID); 3825 JavaCalls::call_static(&result, 3826 shutdown_klass, 3827 vmSymbols::shutdown_method_name(), 3828 vmSymbols::void_method_signature(), 3829 THREAD); 3830 } 3831 CLEAR_PENDING_EXCEPTION; 3832 } 3833 3834 // Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3835 // the program falls off the end of main(). Another VM exit path is through 3836 // vm_exit() when the program calls System.exit() to return a value or when 3837 // there is a serious error in VM. The two shutdown paths are not exactly 3838 // the same, but they share Shutdown.shutdown() at Java level and before_exit() 3839 // and VM_Exit op at VM level. 3840 // 3841 // Shutdown sequence: 3842 // + Shutdown native memory tracking if it is on 3843 // + Wait until we are the last non-daemon thread to execute 3844 // <-- every thing is still working at this moment --> 3845 // + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3846 // shutdown hooks, run finalizers if finalization-on-exit 3847 // + Call before_exit(), prepare for VM exit 3848 // > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3849 // currently the only user of this mechanism is File.deleteOnExit()) 3850 // > stop flat profiler, StatSampler, watcher thread, CMS threads, 3851 // post thread end and vm death events to JVMTI, 3852 // stop signal thread 3853 // + Call JavaThread::exit(), it will: 3854 // > release JNI handle blocks, remove stack guard pages 3855 // > remove this thread from Threads list 3856 // <-- no more Java code from this thread after this point --> 3857 // + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3858 // the compiler threads at safepoint 3859 // <-- do not use anything that could get blocked by Safepoint --> 3860 // + Disable tracing at JNI/JVM barriers 3861 // + Set _vm_exited flag for threads that are still running native code 3862 // + Delete this thread 3863 // + Call exit_globals() 3864 // > deletes tty 3865 // > deletes PerfMemory resources 3866 // + Return to caller 3867 3868 bool Threads::destroy_vm() { 3869 JavaThread* thread = JavaThread::current(); 3870 3871 #ifdef ASSERT 3872 _vm_complete = false; 3873 #endif 3874 // Wait until we are the last non-daemon thread to execute 3875 { MutexLocker nu(Threads_lock); 3876 while (Threads::number_of_non_daemon_threads() > 1) 3877 // This wait should make safepoint checks, wait without a timeout, 3878 // and wait as a suspend-equivalent condition. 3879 // 3880 // Note: If the FlatProfiler is running and this thread is waiting 3881 // for another non-daemon thread to finish, then the FlatProfiler 3882 // is waiting for the external suspend request on this thread to 3883 // complete. wait_for_ext_suspend_completion() will eventually 3884 // timeout, but that takes time. Making this wait a suspend- 3885 // equivalent condition solves that timeout problem. 3886 // 3887 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3888 Mutex::_as_suspend_equivalent_flag); 3889 } 3890 3891 // Hang forever on exit if we are reporting an error. 3892 if (ShowMessageBoxOnError && is_error_reported()) { 3893 os::infinite_sleep(); 3894 } 3895 os::wait_for_keypress_at_exit(); 3896 3897 // run Java level shutdown hooks 3898 thread->invoke_shutdown_hooks(); 3899 3900 before_exit(thread); 3901 3902 thread->exit(true); 3903 3904 // Stop VM thread. 3905 { 3906 // 4945125 The vm thread comes to a safepoint during exit. 3907 // GC vm_operations can get caught at the safepoint, and the 3908 // heap is unparseable if they are caught. Grab the Heap_lock 3909 // to prevent this. The GC vm_operations will not be able to 3910 // queue until after the vm thread is dead. After this point, 3911 // we'll never emerge out of the safepoint before the VM exits. 3912 3913 MutexLocker ml(Heap_lock); 3914 3915 VMThread::wait_for_vm_thread_exit(); 3916 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3917 VMThread::destroy(); 3918 } 3919 3920 // clean up ideal graph printers 3921 #if defined(COMPILER2) && !defined(PRODUCT) 3922 IdealGraphPrinter::clean_up(); 3923 #endif 3924 3925 // Now, all Java threads are gone except daemon threads. Daemon threads 3926 // running Java code or in VM are stopped by the Safepoint. However, 3927 // daemon threads executing native code are still running. But they 3928 // will be stopped at native=>Java/VM barriers. Note that we can't 3929 // simply kill or suspend them, as it is inherently deadlock-prone. 3930 3931 #ifndef PRODUCT 3932 // disable function tracing at JNI/JVM barriers 3933 TraceJNICalls = false; 3934 TraceJVMCalls = false; 3935 TraceRuntimeCalls = false; 3936 #endif 3937 3938 VM_Exit::set_vm_exited(); 3939 3940 notify_vm_shutdown(); 3941 3942 delete thread; 3943 3944 // exit_globals() will delete tty 3945 exit_globals(); 3946 3947 return true; 3948 } 3949 3950 3951 jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 3952 if (version == JNI_VERSION_1_1) return JNI_TRUE; 3953 return is_supported_jni_version(version); 3954 } 3955 3956 3957 jboolean Threads::is_supported_jni_version(jint version) { 3958 if (version == JNI_VERSION_1_2) return JNI_TRUE; 3959 if (version == JNI_VERSION_1_4) return JNI_TRUE; 3960 if (version == JNI_VERSION_1_6) return JNI_TRUE; 3961 if (version == JNI_VERSION_1_8) return JNI_TRUE; 3962 return JNI_FALSE; 3963 } 3964 3965 3966 void Threads::add(JavaThread* p, bool force_daemon) { 3967 // The threads lock must be owned at this point 3968 assert_locked_or_safepoint(Threads_lock); 3969 3970 // See the comment for this method in thread.hpp for its purpose and 3971 // why it is called here. 3972 p->initialize_queues(); 3973 p->set_next(_thread_list); 3974 _thread_list = p; 3975 _number_of_threads++; 3976 oop threadObj = p->threadObj(); 3977 bool daemon = true; 3978 // Bootstrapping problem: threadObj can be null for initial 3979 // JavaThread (or for threads attached via JNI) 3980 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 3981 _number_of_non_daemon_threads++; 3982 daemon = false; 3983 } 3984 3985 ThreadService::add_thread(p, daemon); 3986 3987 // Possible GC point. 3988 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 3989 } 3990 3991 void Threads::remove(JavaThread* p) { 3992 // Extra scope needed for Thread_lock, so we can check 3993 // that we do not remove thread without safepoint code notice 3994 { MutexLocker ml(Threads_lock); 3995 3996 assert(includes(p), "p must be present"); 3997 3998 JavaThread* current = _thread_list; 3999 JavaThread* prev = NULL; 4000 4001 while (current != p) { 4002 prev = current; 4003 current = current->next(); 4004 } 4005 4006 if (prev) { 4007 prev->set_next(current->next()); 4008 } else { 4009 _thread_list = p->next(); 4010 } 4011 _number_of_threads--; 4012 oop threadObj = p->threadObj(); 4013 bool daemon = true; 4014 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4015 _number_of_non_daemon_threads--; 4016 daemon = false; 4017 4018 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4019 // on destroy_vm will wake up. 4020 if (number_of_non_daemon_threads() == 1) { 4021 Threads_lock->notify_all(); 4022 } 4023 } 4024 ThreadService::remove_thread(p, daemon); 4025 4026 // Make sure that safepoint code disregard this thread. This is needed since 4027 // the thread might mess around with locks after this point. This can cause it 4028 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4029 // of this thread since it is removed from the queue. 4030 p->set_terminated_value(); 4031 } // unlock Threads_lock 4032 4033 // Since Events::log uses a lock, we grab it outside the Threads_lock 4034 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4035 } 4036 4037 // Threads_lock must be held when this is called (or must be called during a safepoint) 4038 bool Threads::includes(JavaThread* p) { 4039 assert(Threads_lock->is_locked(), "sanity check"); 4040 ALL_JAVA_THREADS(q) { 4041 if (q == p) { 4042 return true; 4043 } 4044 } 4045 return false; 4046 } 4047 4048 // Operations on the Threads list for GC. These are not explicitly locked, 4049 // but the garbage collector must provide a safe context for them to run. 4050 // In particular, these things should never be called when the Threads_lock 4051 // is held by some other thread. (Note: the Safepoint abstraction also 4052 // uses the Threads_lock to guarantee this property. It also makes sure that 4053 // all threads gets blocked when exiting or starting). 4054 4055 void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4056 ALL_JAVA_THREADS(p) { 4057 p->oops_do(f, cld_f, cf); 4058 } 4059 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4060 } 4061 4062 void Threads::change_thread_claim_parity() { 4063 // Set the new claim parity. 4064 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2, 4065 "Not in range."); 4066 _thread_claim_parity++; 4067 if (_thread_claim_parity == 3) _thread_claim_parity = 1; 4068 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2, 4069 "Not in range."); 4070 } 4071 4072 #ifdef ASSERT 4073 void Threads::assert_all_threads_claimed() { 4074 ALL_JAVA_THREADS(p) { 4075 const int thread_parity = p->oops_do_parity(); 4076 assert((thread_parity == _thread_claim_parity), 4077 err_msg("Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity)); 4078 } 4079 } 4080 #endif // ASSERT 4081 4082 void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4083 int cp = Threads::thread_claim_parity(); 4084 ALL_JAVA_THREADS(p) { 4085 if (p->claim_oops_do(is_par, cp)) { 4086 p->oops_do(f, cld_f, cf); 4087 } 4088 } 4089 VMThread* vmt = VMThread::vm_thread(); 4090 if (vmt->claim_oops_do(is_par, cp)) { 4091 vmt->oops_do(f, cld_f, cf); 4092 } 4093 } 4094 4095 #if INCLUDE_ALL_GCS 4096 // Used by ParallelScavenge 4097 void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4098 ALL_JAVA_THREADS(p) { 4099 q->enqueue(new ThreadRootsTask(p)); 4100 } 4101 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4102 } 4103 4104 // Used by Parallel Old 4105 void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4106 ALL_JAVA_THREADS(p) { 4107 q->enqueue(new ThreadRootsMarkingTask(p)); 4108 } 4109 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4110 } 4111 #endif // INCLUDE_ALL_GCS 4112 4113 void Threads::nmethods_do(CodeBlobClosure* cf) { 4114 ALL_JAVA_THREADS(p) { 4115 p->nmethods_do(cf); 4116 } 4117 VMThread::vm_thread()->nmethods_do(cf); 4118 } 4119 4120 void Threads::metadata_do(void f(Metadata*)) { 4121 ALL_JAVA_THREADS(p) { 4122 p->metadata_do(f); 4123 } 4124 } 4125 4126 class ThreadHandlesClosure : public ThreadClosure { 4127 void (*_f)(Metadata*); 4128 public: 4129 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4130 virtual void do_thread(Thread* thread) { 4131 thread->metadata_handles_do(_f); 4132 } 4133 }; 4134 4135 void Threads::metadata_handles_do(void f(Metadata*)) { 4136 // Only walk the Handles in Thread. 4137 ThreadHandlesClosure handles_closure(f); 4138 threads_do(&handles_closure); 4139 } 4140 4141 void Threads::deoptimized_wrt_marked_nmethods() { 4142 ALL_JAVA_THREADS(p) { 4143 p->deoptimized_wrt_marked_nmethods(); 4144 } 4145 } 4146 4147 4148 // Get count Java threads that are waiting to enter the specified monitor. 4149 GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4150 address monitor, 4151 bool doLock) { 4152 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4153 "must grab Threads_lock or be at safepoint"); 4154 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4155 4156 int i = 0; 4157 { 4158 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4159 ALL_JAVA_THREADS(p) { 4160 if (p->is_Compiler_thread()) continue; 4161 4162 address pending = (address)p->current_pending_monitor(); 4163 if (pending == monitor) { // found a match 4164 if (i < count) result->append(p); // save the first count matches 4165 i++; 4166 } 4167 } 4168 } 4169 return result; 4170 } 4171 4172 4173 JavaThread *Threads::owning_thread_from_monitor_owner(address owner, 4174 bool doLock) { 4175 assert(doLock || 4176 Threads_lock->owned_by_self() || 4177 SafepointSynchronize::is_at_safepoint(), 4178 "must grab Threads_lock or be at safepoint"); 4179 4180 // NULL owner means not locked so we can skip the search 4181 if (owner == NULL) return NULL; 4182 4183 { 4184 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4185 ALL_JAVA_THREADS(p) { 4186 // first, see if owner is the address of a Java thread 4187 if (owner == (address)p) return p; 4188 } 4189 } 4190 // Cannot assert on lack of success here since this function may be 4191 // used by code that is trying to report useful problem information 4192 // like deadlock detection. 4193 if (UseHeavyMonitors) return NULL; 4194 4195 // If we didn't find a matching Java thread and we didn't force use of 4196 // heavyweight monitors, then the owner is the stack address of the 4197 // Lock Word in the owning Java thread's stack. 4198 // 4199 JavaThread* the_owner = NULL; 4200 { 4201 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4202 ALL_JAVA_THREADS(q) { 4203 if (q->is_lock_owned(owner)) { 4204 the_owner = q; 4205 break; 4206 } 4207 } 4208 } 4209 // cannot assert on lack of success here; see above comment 4210 return the_owner; 4211 } 4212 4213 // Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4214 void Threads::print_on(outputStream* st, bool print_stacks, 4215 bool internal_format, bool print_concurrent_locks) { 4216 char buf[32]; 4217 st->print_cr("%s", os::local_time_string(buf, sizeof(buf))); 4218 4219 st->print_cr("Full thread dump %s (%s %s):", 4220 Abstract_VM_Version::vm_name(), 4221 Abstract_VM_Version::vm_release(), 4222 Abstract_VM_Version::vm_info_string()); 4223 st->cr(); 4224 4225 #if INCLUDE_SERVICES 4226 // Dump concurrent locks 4227 ConcurrentLocksDump concurrent_locks; 4228 if (print_concurrent_locks) { 4229 concurrent_locks.dump_at_safepoint(); 4230 } 4231 #endif // INCLUDE_SERVICES 4232 4233 ALL_JAVA_THREADS(p) { 4234 ResourceMark rm; 4235 p->print_on(st); 4236 if (print_stacks) { 4237 if (internal_format) { 4238 p->trace_stack(); 4239 } else { 4240 p->print_stack_on(st); 4241 } 4242 } 4243 st->cr(); 4244 #if INCLUDE_SERVICES 4245 if (print_concurrent_locks) { 4246 concurrent_locks.print_locks_on(p, st); 4247 } 4248 #endif // INCLUDE_SERVICES 4249 } 4250 4251 VMThread::vm_thread()->print_on(st); 4252 st->cr(); 4253 Universe::heap()->print_gc_threads_on(st); 4254 WatcherThread* wt = WatcherThread::watcher_thread(); 4255 if (wt != NULL) { 4256 wt->print_on(st); 4257 st->cr(); 4258 } 4259 CompileBroker::print_compiler_threads_on(st); 4260 st->flush(); 4261 } 4262 4263 // Threads::print_on_error() is called by fatal error handler. It's possible 4264 // that VM is not at safepoint and/or current thread is inside signal handler. 4265 // Don't print stack trace, as the stack may not be walkable. Don't allocate 4266 // memory (even in resource area), it might deadlock the error handler. 4267 void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4268 int buflen) { 4269 bool found_current = false; 4270 st->print_cr("Java Threads: ( => current thread )"); 4271 ALL_JAVA_THREADS(thread) { 4272 bool is_current = (current == thread); 4273 found_current = found_current || is_current; 4274 4275 st->print("%s", is_current ? "=>" : " "); 4276 4277 st->print(PTR_FORMAT, thread); 4278 st->print(" "); 4279 thread->print_on_error(st, buf, buflen); 4280 st->cr(); 4281 } 4282 st->cr(); 4283 4284 st->print_cr("Other Threads:"); 4285 if (VMThread::vm_thread()) { 4286 bool is_current = (current == VMThread::vm_thread()); 4287 found_current = found_current || is_current; 4288 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4289 4290 st->print(PTR_FORMAT, VMThread::vm_thread()); 4291 st->print(" "); 4292 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4293 st->cr(); 4294 } 4295 WatcherThread* wt = WatcherThread::watcher_thread(); 4296 if (wt != NULL) { 4297 bool is_current = (current == wt); 4298 found_current = found_current || is_current; 4299 st->print("%s", is_current ? "=>" : " "); 4300 4301 st->print(PTR_FORMAT, wt); 4302 st->print(" "); 4303 wt->print_on_error(st, buf, buflen); 4304 st->cr(); 4305 } 4306 if (!found_current) { 4307 st->cr(); 4308 st->print("=>" PTR_FORMAT " (exited) ", current); 4309 current->print_on_error(st, buf, buflen); 4310 st->cr(); 4311 } 4312 } 4313 4314 // Internal SpinLock and Mutex 4315 // Based on ParkEvent 4316 4317 // Ad-hoc mutual exclusion primitives: SpinLock and Mux 4318 // 4319 // We employ SpinLocks _only for low-contention, fixed-length 4320 // short-duration critical sections where we're concerned 4321 // about native mutex_t or HotSpot Mutex:: latency. 4322 // The mux construct provides a spin-then-block mutual exclusion 4323 // mechanism. 4324 // 4325 // Testing has shown that contention on the ListLock guarding gFreeList 4326 // is common. If we implement ListLock as a simple SpinLock it's common 4327 // for the JVM to devolve to yielding with little progress. This is true 4328 // despite the fact that the critical sections protected by ListLock are 4329 // extremely short. 4330 // 4331 // TODO-FIXME: ListLock should be of type SpinLock. 4332 // We should make this a 1st-class type, integrated into the lock 4333 // hierarchy as leaf-locks. Critically, the SpinLock structure 4334 // should have sufficient padding to avoid false-sharing and excessive 4335 // cache-coherency traffic. 4336 4337 4338 typedef volatile int SpinLockT; 4339 4340 void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4341 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4342 return; // normal fast-path return 4343 } 4344 4345 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4346 TEVENT(SpinAcquire - ctx); 4347 int ctr = 0; 4348 int Yields = 0; 4349 for (;;) { 4350 while (*adr != 0) { 4351 ++ctr; 4352 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4353 if (Yields > 5) { 4354 os::naked_short_sleep(1); 4355 } else { 4356 os::naked_yield(); 4357 ++Yields; 4358 } 4359 } else { 4360 SpinPause(); 4361 } 4362 } 4363 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4364 } 4365 } 4366 4367 void Thread::SpinRelease(volatile int * adr) { 4368 assert(*adr != 0, "invariant"); 4369 OrderAccess::fence(); // guarantee at least release consistency. 4370 // Roach-motel semantics. 4371 // It's safe if subsequent LDs and STs float "up" into the critical section, 4372 // but prior LDs and STs within the critical section can't be allowed 4373 // to reorder or float past the ST that releases the lock. 4374 // Loads and stores in the critical section - which appear in program 4375 // order before the store that releases the lock - must also appear 4376 // before the store that releases the lock in memory visibility order. 4377 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4378 // the ST of 0 into the lock-word which releases the lock, so fence 4379 // more than covers this on all platforms. 4380 *adr = 0; 4381 } 4382 4383 // muxAcquire and muxRelease: 4384 // 4385 // * muxAcquire and muxRelease support a single-word lock-word construct. 4386 // The LSB of the word is set IFF the lock is held. 4387 // The remainder of the word points to the head of a singly-linked list 4388 // of threads blocked on the lock. 4389 // 4390 // * The current implementation of muxAcquire-muxRelease uses its own 4391 // dedicated Thread._MuxEvent instance. If we're interested in 4392 // minimizing the peak number of extant ParkEvent instances then 4393 // we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4394 // as certain invariants were satisfied. Specifically, care would need 4395 // to be taken with regards to consuming unpark() "permits". 4396 // A safe rule of thumb is that a thread would never call muxAcquire() 4397 // if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4398 // park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4399 // consume an unpark() permit intended for monitorenter, for instance. 4400 // One way around this would be to widen the restricted-range semaphore 4401 // implemented in park(). Another alternative would be to provide 4402 // multiple instances of the PlatformEvent() for each thread. One 4403 // instance would be dedicated to muxAcquire-muxRelease, for instance. 4404 // 4405 // * Usage: 4406 // -- Only as leaf locks 4407 // -- for short-term locking only as muxAcquire does not perform 4408 // thread state transitions. 4409 // 4410 // Alternatives: 4411 // * We could implement muxAcquire and muxRelease with MCS or CLH locks 4412 // but with parking or spin-then-park instead of pure spinning. 4413 // * Use Taura-Oyama-Yonenzawa locks. 4414 // * It's possible to construct a 1-0 lock if we encode the lockword as 4415 // (List,LockByte). Acquire will CAS the full lockword while Release 4416 // will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4417 // acquiring threads use timers (ParkTimed) to detect and recover from 4418 // the stranding window. Thread/Node structures must be aligned on 256-byte 4419 // boundaries by using placement-new. 4420 // * Augment MCS with advisory back-link fields maintained with CAS(). 4421 // Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4422 // The validity of the backlinks must be ratified before we trust the value. 4423 // If the backlinks are invalid the exiting thread must back-track through the 4424 // the forward links, which are always trustworthy. 4425 // * Add a successor indication. The LockWord is currently encoded as 4426 // (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4427 // to provide the usual futile-wakeup optimization. 4428 // See RTStt for details. 4429 // * Consider schedctl.sc_nopreempt to cover the critical section. 4430 // 4431 4432 4433 typedef volatile intptr_t MutexT; // Mux Lock-word 4434 enum MuxBits { LOCKBIT = 1 }; 4435 4436 void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4437 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4438 if (w == 0) return; 4439 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4440 return; 4441 } 4442 4443 TEVENT(muxAcquire - Contention); 4444 ParkEvent * const Self = Thread::current()->_MuxEvent; 4445 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4446 for (;;) { 4447 int its = (os::is_MP() ? 100 : 0) + 1; 4448 4449 // Optional spin phase: spin-then-park strategy 4450 while (--its >= 0) { 4451 w = *Lock; 4452 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4453 return; 4454 } 4455 } 4456 4457 Self->reset(); 4458 Self->OnList = intptr_t(Lock); 4459 // The following fence() isn't _strictly necessary as the subsequent 4460 // CAS() both serializes execution and ratifies the fetched *Lock value. 4461 OrderAccess::fence(); 4462 for (;;) { 4463 w = *Lock; 4464 if ((w & LOCKBIT) == 0) { 4465 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4466 Self->OnList = 0; // hygiene - allows stronger asserts 4467 return; 4468 } 4469 continue; // Interference -- *Lock changed -- Just retry 4470 } 4471 assert(w & LOCKBIT, "invariant"); 4472 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4473 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4474 } 4475 4476 while (Self->OnList != 0) { 4477 Self->park(); 4478 } 4479 } 4480 } 4481 4482 void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4483 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4484 if (w == 0) return; 4485 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4486 return; 4487 } 4488 4489 TEVENT(muxAcquire - Contention); 4490 ParkEvent * ReleaseAfter = NULL; 4491 if (ev == NULL) { 4492 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4493 } 4494 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4495 for (;;) { 4496 guarantee(ev->OnList == 0, "invariant"); 4497 int its = (os::is_MP() ? 100 : 0) + 1; 4498 4499 // Optional spin phase: spin-then-park strategy 4500 while (--its >= 0) { 4501 w = *Lock; 4502 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4503 if (ReleaseAfter != NULL) { 4504 ParkEvent::Release(ReleaseAfter); 4505 } 4506 return; 4507 } 4508 } 4509 4510 ev->reset(); 4511 ev->OnList = intptr_t(Lock); 4512 // The following fence() isn't _strictly necessary as the subsequent 4513 // CAS() both serializes execution and ratifies the fetched *Lock value. 4514 OrderAccess::fence(); 4515 for (;;) { 4516 w = *Lock; 4517 if ((w & LOCKBIT) == 0) { 4518 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4519 ev->OnList = 0; 4520 // We call ::Release while holding the outer lock, thus 4521 // artificially lengthening the critical section. 4522 // Consider deferring the ::Release() until the subsequent unlock(), 4523 // after we've dropped the outer lock. 4524 if (ReleaseAfter != NULL) { 4525 ParkEvent::Release(ReleaseAfter); 4526 } 4527 return; 4528 } 4529 continue; // Interference -- *Lock changed -- Just retry 4530 } 4531 assert(w & LOCKBIT, "invariant"); 4532 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4533 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4534 } 4535 4536 while (ev->OnList != 0) { 4537 ev->park(); 4538 } 4539 } 4540 } 4541 4542 // Release() must extract a successor from the list and then wake that thread. 4543 // It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4544 // similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4545 // Release() would : 4546 // (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4547 // (B) Extract a successor from the private list "in-hand" 4548 // (C) attempt to CAS() the residual back into *Lock over null. 4549 // If there were any newly arrived threads and the CAS() would fail. 4550 // In that case Release() would detach the RATs, re-merge the list in-hand 4551 // with the RATs and repeat as needed. Alternately, Release() might 4552 // detach and extract a successor, but then pass the residual list to the wakee. 4553 // The wakee would be responsible for reattaching and remerging before it 4554 // competed for the lock. 4555 // 4556 // Both "pop" and DMR are immune from ABA corruption -- there can be 4557 // multiple concurrent pushers, but only one popper or detacher. 4558 // This implementation pops from the head of the list. This is unfair, 4559 // but tends to provide excellent throughput as hot threads remain hot. 4560 // (We wake recently run threads first). 4561 // 4562 // All paths through muxRelease() will execute a CAS. 4563 // Release consistency -- We depend on the CAS in muxRelease() to provide full 4564 // bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4565 // executed within the critical section are complete and globally visible before the 4566 // store (CAS) to the lock-word that releases the lock becomes globally visible. 4567 void Thread::muxRelease(volatile intptr_t * Lock) { 4568 for (;;) { 4569 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4570 assert(w & LOCKBIT, "invariant"); 4571 if (w == LOCKBIT) return; 4572 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4573 assert(List != NULL, "invariant"); 4574 assert(List->OnList == intptr_t(Lock), "invariant"); 4575 ParkEvent * const nxt = List->ListNext; 4576 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4577 4578 // The following CAS() releases the lock and pops the head element. 4579 // The CAS() also ratifies the previously fetched lock-word value. 4580 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4581 continue; 4582 } 4583 List->OnList = 0; 4584 OrderAccess::fence(); 4585 List->unpark(); 4586 return; 4587 } 4588 } 4589 4590 4591 void Threads::verify() { 4592 ALL_JAVA_THREADS(p) { 4593 p->verify(); 4594 } 4595 VMThread* thread = VMThread::vm_thread(); 4596 if (thread != NULL) thread->verify(); 4597 }