Old src/share/vm/runtime/thread.cpp (original) (raw)

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