thread.cpp revision 6014:8a9bb7821e28
1/* 2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "precompiled.hpp" 26#include "classfile/classLoader.hpp" 27#include "classfile/javaClasses.hpp" 28#include "classfile/systemDictionary.hpp" 29#include "classfile/vmSymbols.hpp" 30#include "code/scopeDesc.hpp" 31#include "compiler/compileBroker.hpp" 32#include "interpreter/interpreter.hpp" 33#include "interpreter/linkResolver.hpp" 34#include "interpreter/oopMapCache.hpp" 35#include "jvmtifiles/jvmtiEnv.hpp" 36#include "memory/gcLocker.inline.hpp" 37#include "memory/metaspaceShared.hpp" 38#include "memory/oopFactory.hpp" 39#include "memory/universe.inline.hpp" 40#include "oops/instanceKlass.hpp" 41#include "oops/objArrayOop.hpp" 42#include "oops/oop.inline.hpp" 43#include "oops/symbol.hpp" 44#include "prims/jvm_misc.hpp" 45#include "prims/jvmtiExport.hpp" 46#include "prims/jvmtiThreadState.hpp" 47#include "prims/privilegedStack.hpp" 48#include "runtime/arguments.hpp" 49#include "runtime/biasedLocking.hpp" 50#include "runtime/deoptimization.hpp" 51#include "runtime/fprofiler.hpp" 52#include "runtime/frame.inline.hpp" 53#include "runtime/init.hpp" 54#include "runtime/interfaceSupport.hpp" 55#include "runtime/java.hpp" 56#include "runtime/javaCalls.hpp" 57#include "runtime/jniPeriodicChecker.hpp" 58#include "runtime/memprofiler.hpp" 59#include "runtime/mutexLocker.hpp" 60#include "runtime/objectMonitor.hpp" 61#include "runtime/osThread.hpp" 62#include "runtime/safepoint.hpp" 63#include "runtime/sharedRuntime.hpp" 64#include "runtime/statSampler.hpp" 65#include "runtime/stubRoutines.hpp" 66#include "runtime/task.hpp" 67#include "runtime/thread.inline.hpp" 68#include "runtime/threadCritical.hpp" 69#include "runtime/threadLocalStorage.hpp" 70#include "runtime/vframe.hpp" 71#include "runtime/vframeArray.hpp" 72#include "runtime/vframe_hp.hpp" 73#include "runtime/vmThread.hpp" 74#include "runtime/vm_operations.hpp" 75#include "services/attachListener.hpp" 76#include "services/management.hpp" 77#include "services/memTracker.hpp" 78#include "services/threadService.hpp" 79#include "trace/tracing.hpp" 80#include "trace/traceMacros.hpp" 81#include "utilities/defaultStream.hpp" 82#include "utilities/dtrace.hpp" 83#include "utilities/events.hpp" 84#include "utilities/preserveException.hpp" 85#include "utilities/macros.hpp" 86#ifdef TARGET_OS_FAMILY_linux 87# include "os_linux.inline.hpp" 88#endif 89#ifdef TARGET_OS_FAMILY_solaris 90# include "os_solaris.inline.hpp" 91#endif 92#ifdef TARGET_OS_FAMILY_windows 93# include "os_windows.inline.hpp" 94#endif 95#ifdef TARGET_OS_FAMILY_bsd 96# include "os_bsd.inline.hpp" 97#endif 98#if INCLUDE_ALL_GCS 99#include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 100#include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 101#include "gc_implementation/parallelScavenge/pcTasks.hpp" 102#endif // INCLUDE_ALL_GCS 103#ifdef COMPILER1 104#include "c1/c1_Compiler.hpp" 105#endif 106#ifdef COMPILER2 107#include "opto/c2compiler.hpp" 108#include "opto/idealGraphPrinter.hpp" 109#endif 110 111#ifdef DTRACE_ENABLED 112 113// Only bother with this argument setup if dtrace is available 114 115#ifndef USDT2 116HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 117HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 118HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 119 intptr_t, intptr_t, bool); 120HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 121 intptr_t, intptr_t, bool); 122 123#define DTRACE_THREAD_PROBE(probe, javathread) \ 124 { \ 125 ResourceMark rm(this); \ 126 int len = 0; \ 127 const char* name = (javathread)->get_thread_name(); \ 128 len = strlen(name); \ 129 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 130 name, len, \ 131 java_lang_Thread::thread_id((javathread)->threadObj()), \ 132 (javathread)->osthread()->thread_id(), \ 133 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 134 } 135 136#else /* USDT2 */ 137 138#define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 139#define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 140 141#define DTRACE_THREAD_PROBE(probe, javathread) \ 142 { \ 143 ResourceMark rm(this); \ 144 int len = 0; \ 145 const char* name = (javathread)->get_thread_name(); \ 146 len = strlen(name); \ 147 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 148 (char *) name, len, \ 149 java_lang_Thread::thread_id((javathread)->threadObj()), \ 150 (uintptr_t) (javathread)->osthread()->thread_id(), \ 151 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 152 } 153 154#endif /* USDT2 */ 155 156#else // ndef DTRACE_ENABLED 157 158#define DTRACE_THREAD_PROBE(probe, javathread) 159 160#endif // ndef DTRACE_ENABLED 161 162 163// Class hierarchy 164// - Thread 165// - VMThread 166// - WatcherThread 167// - ConcurrentMarkSweepThread 168// - JavaThread 169// - CompilerThread 170 171// ======= Thread ======== 172// Support for forcing alignment of thread objects for biased locking 173void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 174 if (UseBiasedLocking) { 175 const int alignment = markOopDesc::biased_lock_alignment; 176 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 178 : AllocateHeap(aligned_size, flags, CURRENT_PC, 179 AllocFailStrategy::RETURN_NULL); 180 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 183 "JavaThread alignment code overflowed allocated storage"); 184 if (TraceBiasedLocking) { 185 if (aligned_addr != real_malloc_addr) 186 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 187 real_malloc_addr, aligned_addr); 188 } 189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 190 return aligned_addr; 191 } else { 192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 194 } 195} 196 197void Thread::operator delete(void* p) { 198 if (UseBiasedLocking) { 199 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 200 FreeHeap(real_malloc_addr, mtThread); 201 } else { 202 FreeHeap(p, mtThread); 203 } 204} 205 206 207// Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 208// JavaThread 209 210 211Thread::Thread() { 212 // stack and get_thread 213 set_stack_base(NULL); 214 set_stack_size(0); 215 set_self_raw_id(0); 216 set_lgrp_id(-1); 217 218 // allocated data structures 219 set_osthread(NULL); 220 set_resource_area(new (mtThread)ResourceArea()); 221 DEBUG_ONLY(_current_resource_mark = NULL;) 222 set_handle_area(new (mtThread) HandleArea(NULL)); 223 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 224 set_active_handles(NULL); 225 set_free_handle_block(NULL); 226 set_last_handle_mark(NULL); 227 228 // This initial value ==> never claimed. 229 _oops_do_parity = 0; 230 231 // the handle mark links itself to last_handle_mark 232 new HandleMark(this); 233 234 // plain initialization 235 debug_only(_owned_locks = NULL;) 236 debug_only(_allow_allocation_count = 0;) 237 NOT_PRODUCT(_allow_safepoint_count = 0;) 238 NOT_PRODUCT(_skip_gcalot = false;) 239 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;) 240 _jvmti_env_iteration_count = 0; 241 set_allocated_bytes(0); 242 _vm_operation_started_count = 0; 243 _vm_operation_completed_count = 0; 244 _current_pending_monitor = NULL; 245 _current_pending_monitor_is_from_java = true; 246 _current_waiting_monitor = NULL; 247 _num_nested_signal = 0; 248 omFreeList = NULL ; 249 omFreeCount = 0 ; 250 omFreeProvision = 32 ; 251 omInUseList = NULL ; 252 omInUseCount = 0 ; 253 254#ifdef ASSERT 255 _visited_for_critical_count = false; 256#endif 257 258 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 259 _suspend_flags = 0; 260 261 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 262 _hashStateX = os::random() ; 263 _hashStateY = 842502087 ; 264 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 265 _hashStateW = 273326509 ; 266 267 _OnTrap = 0 ; 268 _schedctl = NULL ; 269 _Stalled = 0 ; 270 _TypeTag = 0x2BAD ; 271 272 // Many of the following fields are effectively final - immutable 273 // Note that nascent threads can't use the Native Monitor-Mutex 274 // construct until the _MutexEvent is initialized ... 275 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 276 // we might instead use a stack of ParkEvents that we could provision on-demand. 277 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 278 // and ::Release() 279 _ParkEvent = ParkEvent::Allocate (this) ; 280 _SleepEvent = ParkEvent::Allocate (this) ; 281 _MutexEvent = ParkEvent::Allocate (this) ; 282 _MuxEvent = ParkEvent::Allocate (this) ; 283 284#ifdef CHECK_UNHANDLED_OOPS 285 if (CheckUnhandledOops) { 286 _unhandled_oops = new UnhandledOops(this); 287 } 288#endif // CHECK_UNHANDLED_OOPS 289#ifdef ASSERT 290 if (UseBiasedLocking) { 291 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 292 assert(this == _real_malloc_address || 293 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 294 "bug in forced alignment of thread objects"); 295 } 296#endif /* ASSERT */ 297} 298 299void Thread::initialize_thread_local_storage() { 300 // Note: Make sure this method only calls 301 // non-blocking operations. Otherwise, it might not work 302 // with the thread-startup/safepoint interaction. 303 304 // During Java thread startup, safepoint code should allow this 305 // method to complete because it may need to allocate memory to 306 // store information for the new thread. 307 308 // initialize structure dependent on thread local storage 309 ThreadLocalStorage::set_thread(this); 310} 311 312void Thread::record_stack_base_and_size() { 313 set_stack_base(os::current_stack_base()); 314 set_stack_size(os::current_stack_size()); 315 if (is_Java_thread()) { 316 ((JavaThread*) this)->set_stack_overflow_limit(); 317 } 318 // CR 7190089: on Solaris, primordial thread's stack is adjusted 319 // in initialize_thread(). Without the adjustment, stack size is 320 // incorrect if stack is set to unlimited (ulimit -s unlimited). 321 // So far, only Solaris has real implementation of initialize_thread(). 322 // 323 // set up any platform-specific state. 324 os::initialize_thread(this); 325 326#if INCLUDE_NMT 327 // record thread's native stack, stack grows downward 328 address stack_low_addr = stack_base() - stack_size(); 329 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 330 CURRENT_PC); 331#endif // INCLUDE_NMT 332} 333 334 335Thread::~Thread() { 336 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 337 ObjectSynchronizer::omFlush (this) ; 338 339 EVENT_THREAD_DESTRUCT(this); 340 341 // stack_base can be NULL if the thread is never started or exited before 342 // record_stack_base_and_size called. Although, we would like to ensure 343 // that all started threads do call record_stack_base_and_size(), there is 344 // not proper way to enforce that. 345#if INCLUDE_NMT 346 if (_stack_base != NULL) { 347 address low_stack_addr = stack_base() - stack_size(); 348 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); 349#ifdef ASSERT 350 set_stack_base(NULL); 351#endif 352 } 353#endif // INCLUDE_NMT 354 355 // deallocate data structures 356 delete resource_area(); 357 // since the handle marks are using the handle area, we have to deallocated the root 358 // handle mark before deallocating the thread's handle area, 359 assert(last_handle_mark() != NULL, "check we have an element"); 360 delete last_handle_mark(); 361 assert(last_handle_mark() == NULL, "check we have reached the end"); 362 363 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 364 // We NULL out the fields for good hygiene. 365 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 366 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 367 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 368 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 369 370 delete handle_area(); 371 delete metadata_handles(); 372 373 // osthread() can be NULL, if creation of thread failed. 374 if (osthread() != NULL) os::free_thread(osthread()); 375 376 delete _SR_lock; 377 378 // clear thread local storage if the Thread is deleting itself 379 if (this == Thread::current()) { 380 ThreadLocalStorage::set_thread(NULL); 381 } else { 382 // In the case where we're not the current thread, invalidate all the 383 // caches in case some code tries to get the current thread or the 384 // thread that was destroyed, and gets stale information. 385 ThreadLocalStorage::invalidate_all(); 386 } 387 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 388} 389 390// NOTE: dummy function for assertion purpose. 391void Thread::run() { 392 ShouldNotReachHere(); 393} 394 395#ifdef ASSERT 396// Private method to check for dangling thread pointer 397void check_for_dangling_thread_pointer(Thread *thread) { 398 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 399 "possibility of dangling Thread pointer"); 400} 401#endif 402 403 404#ifndef PRODUCT 405// Tracing method for basic thread operations 406void Thread::trace(const char* msg, const Thread* const thread) { 407 if (!TraceThreadEvents) return; 408 ResourceMark rm; 409 ThreadCritical tc; 410 const char *name = "non-Java thread"; 411 int prio = -1; 412 if (thread->is_Java_thread() 413 && !thread->is_Compiler_thread()) { 414 // The Threads_lock must be held to get information about 415 // this thread but may not be in some situations when 416 // tracing thread events. 417 bool release_Threads_lock = false; 418 if (!Threads_lock->owned_by_self()) { 419 Threads_lock->lock(); 420 release_Threads_lock = true; 421 } 422 JavaThread* jt = (JavaThread *)thread; 423 name = (char *)jt->get_thread_name(); 424 oop thread_oop = jt->threadObj(); 425 if (thread_oop != NULL) { 426 prio = java_lang_Thread::priority(thread_oop); 427 } 428 if (release_Threads_lock) { 429 Threads_lock->unlock(); 430 } 431 } 432 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 433} 434#endif 435 436 437ThreadPriority Thread::get_priority(const Thread* const thread) { 438 trace("get priority", thread); 439 ThreadPriority priority; 440 // Can return an error! 441 (void)os::get_priority(thread, priority); 442 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 443 return priority; 444} 445 446void Thread::set_priority(Thread* thread, ThreadPriority priority) { 447 trace("set priority", thread); 448 debug_only(check_for_dangling_thread_pointer(thread);) 449 // Can return an error! 450 (void)os::set_priority(thread, priority); 451} 452 453 454void Thread::start(Thread* thread) { 455 trace("start", thread); 456 // Start is different from resume in that its safety is guaranteed by context or 457 // being called from a Java method synchronized on the Thread object. 458 if (!DisableStartThread) { 459 if (thread->is_Java_thread()) { 460 // Initialize the thread state to RUNNABLE before starting this thread. 461 // Can not set it after the thread started because we do not know the 462 // exact thread state at that time. It could be in MONITOR_WAIT or 463 // in SLEEPING or some other state. 464 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 465 java_lang_Thread::RUNNABLE); 466 } 467 os::start_thread(thread); 468 } 469} 470 471// Enqueue a VM_Operation to do the job for us - sometime later 472void Thread::send_async_exception(oop java_thread, oop java_throwable) { 473 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 474 VMThread::execute(vm_stop); 475} 476 477 478// 479// Check if an external suspend request has completed (or has been 480// cancelled). Returns true if the thread is externally suspended and 481// false otherwise. 482// 483// The bits parameter returns information about the code path through 484// the routine. Useful for debugging: 485// 486// set in is_ext_suspend_completed(): 487// 0x00000001 - routine was entered 488// 0x00000010 - routine return false at end 489// 0x00000100 - thread exited (return false) 490// 0x00000200 - suspend request cancelled (return false) 491// 0x00000400 - thread suspended (return true) 492// 0x00001000 - thread is in a suspend equivalent state (return true) 493// 0x00002000 - thread is native and walkable (return true) 494// 0x00004000 - thread is native_trans and walkable (needed retry) 495// 496// set in wait_for_ext_suspend_completion(): 497// 0x00010000 - routine was entered 498// 0x00020000 - suspend request cancelled before loop (return false) 499// 0x00040000 - thread suspended before loop (return true) 500// 0x00080000 - suspend request cancelled in loop (return false) 501// 0x00100000 - thread suspended in loop (return true) 502// 0x00200000 - suspend not completed during retry loop (return false) 503// 504 505// Helper class for tracing suspend wait debug bits. 506// 507// 0x00000100 indicates that the target thread exited before it could 508// self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 509// 0x00080000 each indicate a cancelled suspend request so they don't 510// count as wait failures either. 511#define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 512 513class TraceSuspendDebugBits : public StackObj { 514 private: 515 JavaThread * jt; 516 bool is_wait; 517 bool called_by_wait; // meaningful when !is_wait 518 uint32_t * bits; 519 520 public: 521 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 522 uint32_t *_bits) { 523 jt = _jt; 524 is_wait = _is_wait; 525 called_by_wait = _called_by_wait; 526 bits = _bits; 527 } 528 529 ~TraceSuspendDebugBits() { 530 if (!is_wait) { 531#if 1 532 // By default, don't trace bits for is_ext_suspend_completed() calls. 533 // That trace is very chatty. 534 return; 535#else 536 if (!called_by_wait) { 537 // If tracing for is_ext_suspend_completed() is enabled, then only 538 // trace calls to it from wait_for_ext_suspend_completion() 539 return; 540 } 541#endif 542 } 543 544 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 545 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 546 MutexLocker ml(Threads_lock); // needed for get_thread_name() 547 ResourceMark rm; 548 549 tty->print_cr( 550 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 551 jt->get_thread_name(), *bits); 552 553 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 554 } 555 } 556 } 557}; 558#undef DEBUG_FALSE_BITS 559 560 561bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 562 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 563 564 bool did_trans_retry = false; // only do thread_in_native_trans retry once 565 bool do_trans_retry; // flag to force the retry 566 567 *bits |= 0x00000001; 568 569 do { 570 do_trans_retry = false; 571 572 if (is_exiting()) { 573 // Thread is in the process of exiting. This is always checked 574 // first to reduce the risk of dereferencing a freed JavaThread. 575 *bits |= 0x00000100; 576 return false; 577 } 578 579 if (!is_external_suspend()) { 580 // Suspend request is cancelled. This is always checked before 581 // is_ext_suspended() to reduce the risk of a rogue resume 582 // confusing the thread that made the suspend request. 583 *bits |= 0x00000200; 584 return false; 585 } 586 587 if (is_ext_suspended()) { 588 // thread is suspended 589 *bits |= 0x00000400; 590 return true; 591 } 592 593 // Now that we no longer do hard suspends of threads running 594 // native code, the target thread can be changing thread state 595 // while we are in this routine: 596 // 597 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 598 // 599 // We save a copy of the thread state as observed at this moment 600 // and make our decision about suspend completeness based on the 601 // copy. This closes the race where the thread state is seen as 602 // _thread_in_native_trans in the if-thread_blocked check, but is 603 // seen as _thread_blocked in if-thread_in_native_trans check. 604 JavaThreadState save_state = thread_state(); 605 606 if (save_state == _thread_blocked && is_suspend_equivalent()) { 607 // If the thread's state is _thread_blocked and this blocking 608 // condition is known to be equivalent to a suspend, then we can 609 // consider the thread to be externally suspended. This means that 610 // the code that sets _thread_blocked has been modified to do 611 // self-suspension if the blocking condition releases. We also 612 // used to check for CONDVAR_WAIT here, but that is now covered by 613 // the _thread_blocked with self-suspension check. 614 // 615 // Return true since we wouldn't be here unless there was still an 616 // external suspend request. 617 *bits |= 0x00001000; 618 return true; 619 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 620 // Threads running native code will self-suspend on native==>VM/Java 621 // transitions. If its stack is walkable (should always be the case 622 // unless this function is called before the actual java_suspend() 623 // call), then the wait is done. 624 *bits |= 0x00002000; 625 return true; 626 } else if (!called_by_wait && !did_trans_retry && 627 save_state == _thread_in_native_trans && 628 frame_anchor()->walkable()) { 629 // The thread is transitioning from thread_in_native to another 630 // thread state. check_safepoint_and_suspend_for_native_trans() 631 // will force the thread to self-suspend. If it hasn't gotten 632 // there yet we may have caught the thread in-between the native 633 // code check above and the self-suspend. Lucky us. If we were 634 // called by wait_for_ext_suspend_completion(), then it 635 // will be doing the retries so we don't have to. 636 // 637 // Since we use the saved thread state in the if-statement above, 638 // there is a chance that the thread has already transitioned to 639 // _thread_blocked by the time we get here. In that case, we will 640 // make a single unnecessary pass through the logic below. This 641 // doesn't hurt anything since we still do the trans retry. 642 643 *bits |= 0x00004000; 644 645 // Once the thread leaves thread_in_native_trans for another 646 // thread state, we break out of this retry loop. We shouldn't 647 // need this flag to prevent us from getting back here, but 648 // sometimes paranoia is good. 649 did_trans_retry = true; 650 651 // We wait for the thread to transition to a more usable state. 652 for (int i = 1; i <= SuspendRetryCount; i++) { 653 // We used to do an "os::yield_all(i)" call here with the intention 654 // that yielding would increase on each retry. However, the parameter 655 // is ignored on Linux which means the yield didn't scale up. Waiting 656 // on the SR_lock below provides a much more predictable scale up for 657 // the delay. It also provides a simple/direct point to check for any 658 // safepoint requests from the VMThread 659 660 // temporarily drops SR_lock while doing wait with safepoint check 661 // (if we're a JavaThread - the WatcherThread can also call this) 662 // and increase delay with each retry 663 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 664 665 // check the actual thread state instead of what we saved above 666 if (thread_state() != _thread_in_native_trans) { 667 // the thread has transitioned to another thread state so 668 // try all the checks (except this one) one more time. 669 do_trans_retry = true; 670 break; 671 } 672 } // end retry loop 673 674 675 } 676 } while (do_trans_retry); 677 678 *bits |= 0x00000010; 679 return false; 680} 681 682// 683// Wait for an external suspend request to complete (or be cancelled). 684// Returns true if the thread is externally suspended and false otherwise. 685// 686bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 687 uint32_t *bits) { 688 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 689 false /* !called_by_wait */, bits); 690 691 // local flag copies to minimize SR_lock hold time 692 bool is_suspended; 693 bool pending; 694 uint32_t reset_bits; 695 696 // set a marker so is_ext_suspend_completed() knows we are the caller 697 *bits |= 0x00010000; 698 699 // We use reset_bits to reinitialize the bits value at the top of 700 // each retry loop. This allows the caller to make use of any 701 // unused bits for their own marking purposes. 702 reset_bits = *bits; 703 704 { 705 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 706 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 707 delay, bits); 708 pending = is_external_suspend(); 709 } 710 // must release SR_lock to allow suspension to complete 711 712 if (!pending) { 713 // A cancelled suspend request is the only false return from 714 // is_ext_suspend_completed() that keeps us from entering the 715 // retry loop. 716 *bits |= 0x00020000; 717 return false; 718 } 719 720 if (is_suspended) { 721 *bits |= 0x00040000; 722 return true; 723 } 724 725 for (int i = 1; i <= retries; i++) { 726 *bits = reset_bits; // reinit to only track last retry 727 728 // We used to do an "os::yield_all(i)" call here with the intention 729 // that yielding would increase on each retry. However, the parameter 730 // is ignored on Linux which means the yield didn't scale up. Waiting 731 // on the SR_lock below provides a much more predictable scale up for 732 // the delay. It also provides a simple/direct point to check for any 733 // safepoint requests from the VMThread 734 735 { 736 MutexLocker ml(SR_lock()); 737 // wait with safepoint check (if we're a JavaThread - the WatcherThread 738 // can also call this) and increase delay with each retry 739 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 740 741 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 742 delay, bits); 743 744 // It is possible for the external suspend request to be cancelled 745 // (by a resume) before the actual suspend operation is completed. 746 // Refresh our local copy to see if we still need to wait. 747 pending = is_external_suspend(); 748 } 749 750 if (!pending) { 751 // A cancelled suspend request is the only false return from 752 // is_ext_suspend_completed() that keeps us from staying in the 753 // retry loop. 754 *bits |= 0x00080000; 755 return false; 756 } 757 758 if (is_suspended) { 759 *bits |= 0x00100000; 760 return true; 761 } 762 } // end retry loop 763 764 // thread did not suspend after all our retries 765 *bits |= 0x00200000; 766 return false; 767} 768 769#ifndef PRODUCT 770void JavaThread::record_jump(address target, address instr, const char* file, int line) { 771 772 // This should not need to be atomic as the only way for simultaneous 773 // updates is via interrupts. Even then this should be rare or non-existent 774 // and we don't care that much anyway. 775 776 int index = _jmp_ring_index; 777 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 778 _jmp_ring[index]._target = (intptr_t) target; 779 _jmp_ring[index]._instruction = (intptr_t) instr; 780 _jmp_ring[index]._file = file; 781 _jmp_ring[index]._line = line; 782} 783#endif /* PRODUCT */ 784 785// Called by flat profiler 786// Callers have already called wait_for_ext_suspend_completion 787// The assertion for that is currently too complex to put here: 788bool JavaThread::profile_last_Java_frame(frame* _fr) { 789 bool gotframe = false; 790 // self suspension saves needed state. 791 if (has_last_Java_frame() && _anchor.walkable()) { 792 *_fr = pd_last_frame(); 793 gotframe = true; 794 } 795 return gotframe; 796} 797 798void Thread::interrupt(Thread* thread) { 799 trace("interrupt", thread); 800 debug_only(check_for_dangling_thread_pointer(thread);) 801 os::interrupt(thread); 802} 803 804bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 805 trace("is_interrupted", thread); 806 debug_only(check_for_dangling_thread_pointer(thread);) 807 // Note: If clear_interrupted==false, this simply fetches and 808 // returns the value of the field osthread()->interrupted(). 809 return os::is_interrupted(thread, clear_interrupted); 810} 811 812 813// GC Support 814bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 815 jint thread_parity = _oops_do_parity; 816 if (thread_parity != strong_roots_parity) { 817 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 818 if (res == thread_parity) { 819 return true; 820 } else { 821 guarantee(res == strong_roots_parity, "Or else what?"); 822 assert(SharedHeap::heap()->workers()->active_workers() > 0, 823 "Should only fail when parallel."); 824 return false; 825 } 826 } 827 assert(SharedHeap::heap()->workers()->active_workers() > 0, 828 "Should only fail when parallel."); 829 return false; 830} 831 832void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 833 active_handles()->oops_do(f); 834 // Do oop for ThreadShadow 835 f->do_oop((oop*)&_pending_exception); 836 handle_area()->oops_do(f); 837} 838 839void Thread::nmethods_do(CodeBlobClosure* cf) { 840 // no nmethods in a generic thread... 841} 842 843void Thread::metadata_do(void f(Metadata*)) { 844 if (metadata_handles() != NULL) { 845 for (int i = 0; i< metadata_handles()->length(); i++) { 846 f(metadata_handles()->at(i)); 847 } 848 } 849} 850 851void Thread::print_on(outputStream* st) const { 852 // get_priority assumes osthread initialized 853 if (osthread() != NULL) { 854 int os_prio; 855 if (os::get_native_priority(this, &os_prio) == OS_OK) { 856 st->print("os_prio=%d ", os_prio); 857 } 858 st->print("tid=" INTPTR_FORMAT " ", this); 859 osthread()->print_on(st); 860 } 861 debug_only(if (WizardMode) print_owned_locks_on(st);) 862} 863 864// Thread::print_on_error() is called by fatal error handler. Don't use 865// any lock or allocate memory. 866void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 867 if (is_VM_thread()) st->print("VMThread"); 868 else if (is_Compiler_thread()) st->print("CompilerThread"); 869 else if (is_Java_thread()) st->print("JavaThread"); 870 else if (is_GC_task_thread()) st->print("GCTaskThread"); 871 else if (is_Watcher_thread()) st->print("WatcherThread"); 872 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 873 else st->print("Thread"); 874 875 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 876 _stack_base - _stack_size, _stack_base); 877 878 if (osthread()) { 879 st->print(" [id=%d]", osthread()->thread_id()); 880 } 881} 882 883#ifdef ASSERT 884void Thread::print_owned_locks_on(outputStream* st) const { 885 Monitor *cur = _owned_locks; 886 if (cur == NULL) { 887 st->print(" (no locks) "); 888 } else { 889 st->print_cr(" Locks owned:"); 890 while(cur) { 891 cur->print_on(st); 892 cur = cur->next(); 893 } 894 } 895} 896 897static int ref_use_count = 0; 898 899bool Thread::owns_locks_but_compiled_lock() const { 900 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 901 if (cur != Compile_lock) return true; 902 } 903 return false; 904} 905 906 907#endif 908 909#ifndef PRODUCT 910 911// The flag: potential_vm_operation notifies if this particular safepoint state could potential 912// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 913// no threads which allow_vm_block's are held 914void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 915 // Check if current thread is allowed to block at a safepoint 916 if (!(_allow_safepoint_count == 0)) 917 fatal("Possible safepoint reached by thread that does not allow it"); 918 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 919 fatal("LEAF method calling lock?"); 920 } 921 922#ifdef ASSERT 923 if (potential_vm_operation && is_Java_thread() 924 && !Universe::is_bootstrapping()) { 925 // Make sure we do not hold any locks that the VM thread also uses. 926 // This could potentially lead to deadlocks 927 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 928 // Threads_lock is special, since the safepoint synchronization will not start before this is 929 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 930 // since it is used to transfer control between JavaThreads and the VMThread 931 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 932 if ( (cur->allow_vm_block() && 933 cur != Threads_lock && 934 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 935 cur != VMOperationRequest_lock && 936 cur != VMOperationQueue_lock) || 937 cur->rank() == Mutex::special) { 938 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 939 } 940 } 941 } 942 943 if (GCALotAtAllSafepoints) { 944 // We could enter a safepoint here and thus have a gc 945 InterfaceSupport::check_gc_alot(); 946 } 947#endif 948} 949#endif 950 951bool Thread::is_in_stack(address adr) const { 952 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 953 address end = os::current_stack_pointer(); 954 // Allow non Java threads to call this without stack_base 955 if (_stack_base == NULL) return true; 956 if (stack_base() >= adr && adr >= end) return true; 957 958 return false; 959} 960 961 962bool Thread::is_in_usable_stack(address adr) const { 963 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 964 size_t usable_stack_size = _stack_size - stack_guard_size; 965 966 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 967} 968 969 970// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 971// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 972// used for compilation in the future. If that change is made, the need for these methods 973// should be revisited, and they should be removed if possible. 974 975bool Thread::is_lock_owned(address adr) const { 976 return on_local_stack(adr); 977} 978 979bool Thread::set_as_starting_thread() { 980 // NOTE: this must be called inside the main thread. 981 return os::create_main_thread((JavaThread*)this); 982} 983 984static void initialize_class(Symbol* class_name, TRAPS) { 985 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 986 InstanceKlass::cast(klass)->initialize(CHECK); 987} 988 989 990// Creates the initial ThreadGroup 991static Handle create_initial_thread_group(TRAPS) { 992 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 993 instanceKlassHandle klass (THREAD, k); 994 995 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 996 { 997 JavaValue result(T_VOID); 998 JavaCalls::call_special(&result, 999 system_instance, 1000 klass, 1001 vmSymbols::object_initializer_name(), 1002 vmSymbols::void_method_signature(), 1003 CHECK_NH); 1004 } 1005 Universe::set_system_thread_group(system_instance()); 1006 1007 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 1008 { 1009 JavaValue result(T_VOID); 1010 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 1011 JavaCalls::call_special(&result, 1012 main_instance, 1013 klass, 1014 vmSymbols::object_initializer_name(), 1015 vmSymbols::threadgroup_string_void_signature(), 1016 system_instance, 1017 string, 1018 CHECK_NH); 1019 } 1020 return main_instance; 1021} 1022 1023// Creates the initial Thread 1024static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1025 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1026 instanceKlassHandle klass (THREAD, k); 1027 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1028 1029 java_lang_Thread::set_thread(thread_oop(), thread); 1030 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1031 thread->set_threadObj(thread_oop()); 1032 1033 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1034 1035 JavaValue result(T_VOID); 1036 JavaCalls::call_special(&result, thread_oop, 1037 klass, 1038 vmSymbols::object_initializer_name(), 1039 vmSymbols::threadgroup_string_void_signature(), 1040 thread_group, 1041 string, 1042 CHECK_NULL); 1043 return thread_oop(); 1044} 1045 1046static void call_initializeSystemClass(TRAPS) { 1047 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1048 instanceKlassHandle klass (THREAD, k); 1049 1050 JavaValue result(T_VOID); 1051 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1052 vmSymbols::void_method_signature(), CHECK); 1053} 1054 1055char java_runtime_name[128] = ""; 1056char java_runtime_version[128] = ""; 1057 1058// extract the JRE name from sun.misc.Version.java_runtime_name 1059static const char* get_java_runtime_name(TRAPS) { 1060 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1061 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1062 fieldDescriptor fd; 1063 bool found = k != NULL && 1064 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1065 vmSymbols::string_signature(), &fd); 1066 if (found) { 1067 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1068 if (name_oop == NULL) 1069 return NULL; 1070 const char* name = java_lang_String::as_utf8_string(name_oop, 1071 java_runtime_name, 1072 sizeof(java_runtime_name)); 1073 return name; 1074 } else { 1075 return NULL; 1076 } 1077} 1078 1079// extract the JRE version from sun.misc.Version.java_runtime_version 1080static const char* get_java_runtime_version(TRAPS) { 1081 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1082 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1083 fieldDescriptor fd; 1084 bool found = k != NULL && 1085 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1086 vmSymbols::string_signature(), &fd); 1087 if (found) { 1088 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1089 if (name_oop == NULL) 1090 return NULL; 1091 const char* name = java_lang_String::as_utf8_string(name_oop, 1092 java_runtime_version, 1093 sizeof(java_runtime_version)); 1094 return name; 1095 } else { 1096 return NULL; 1097 } 1098} 1099 1100// General purpose hook into Java code, run once when the VM is initialized. 1101// The Java library method itself may be changed independently from the VM. 1102static void call_postVMInitHook(TRAPS) { 1103 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1104 instanceKlassHandle klass (THREAD, k); 1105 if (klass.not_null()) { 1106 JavaValue result(T_VOID); 1107 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1108 vmSymbols::void_method_signature(), 1109 CHECK); 1110 } 1111} 1112 1113static void reset_vm_info_property(TRAPS) { 1114 // the vm info string 1115 ResourceMark rm(THREAD); 1116 const char *vm_info = VM_Version::vm_info_string(); 1117 1118 // java.lang.System class 1119 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1120 instanceKlassHandle klass (THREAD, k); 1121 1122 // setProperty arguments 1123 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1124 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1125 1126 // return value 1127 JavaValue r(T_OBJECT); 1128 1129 // public static String setProperty(String key, String value); 1130 JavaCalls::call_static(&r, 1131 klass, 1132 vmSymbols::setProperty_name(), 1133 vmSymbols::string_string_string_signature(), 1134 key_str, 1135 value_str, 1136 CHECK); 1137} 1138 1139 1140void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1141 assert(thread_group.not_null(), "thread group should be specified"); 1142 assert(threadObj() == NULL, "should only create Java thread object once"); 1143 1144 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1145 instanceKlassHandle klass (THREAD, k); 1146 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1147 1148 java_lang_Thread::set_thread(thread_oop(), this); 1149 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1150 set_threadObj(thread_oop()); 1151 1152 JavaValue result(T_VOID); 1153 if (thread_name != NULL) { 1154 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1155 // Thread gets assigned specified name and null target 1156 JavaCalls::call_special(&result, 1157 thread_oop, 1158 klass, 1159 vmSymbols::object_initializer_name(), 1160 vmSymbols::threadgroup_string_void_signature(), 1161 thread_group, // Argument 1 1162 name, // Argument 2 1163 THREAD); 1164 } else { 1165 // Thread gets assigned name "Thread-nnn" and null target 1166 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1167 JavaCalls::call_special(&result, 1168 thread_oop, 1169 klass, 1170 vmSymbols::object_initializer_name(), 1171 vmSymbols::threadgroup_runnable_void_signature(), 1172 thread_group, // Argument 1 1173 Handle(), // Argument 2 1174 THREAD); 1175 } 1176 1177 1178 if (daemon) { 1179 java_lang_Thread::set_daemon(thread_oop()); 1180 } 1181 1182 if (HAS_PENDING_EXCEPTION) { 1183 return; 1184 } 1185 1186 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1187 Handle threadObj(this, this->threadObj()); 1188 1189 JavaCalls::call_special(&result, 1190 thread_group, 1191 group, 1192 vmSymbols::add_method_name(), 1193 vmSymbols::thread_void_signature(), 1194 threadObj, // Arg 1 1195 THREAD); 1196 1197 1198} 1199 1200// NamedThread -- non-JavaThread subclasses with multiple 1201// uniquely named instances should derive from this. 1202NamedThread::NamedThread() : Thread() { 1203 _name = NULL; 1204 _processed_thread = NULL; 1205} 1206 1207NamedThread::~NamedThread() { 1208 if (_name != NULL) { 1209 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1210 _name = NULL; 1211 } 1212} 1213 1214void NamedThread::set_name(const char* format, ...) { 1215 guarantee(_name == NULL, "Only get to set name once."); 1216 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1217 guarantee(_name != NULL, "alloc failure"); 1218 va_list ap; 1219 va_start(ap, format); 1220 jio_vsnprintf(_name, max_name_len, format, ap); 1221 va_end(ap); 1222} 1223 1224// ======= WatcherThread ======== 1225 1226// The watcher thread exists to simulate timer interrupts. It should 1227// be replaced by an abstraction over whatever native support for 1228// timer interrupts exists on the platform. 1229 1230WatcherThread* WatcherThread::_watcher_thread = NULL; 1231bool WatcherThread::_startable = false; 1232volatile bool WatcherThread::_should_terminate = false; 1233 1234WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1235 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1236 if (os::create_thread(this, os::watcher_thread)) { 1237 _watcher_thread = this; 1238 1239 // Set the watcher thread to the highest OS priority which should not be 1240 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1241 // is created. The only normal thread using this priority is the reference 1242 // handler thread, which runs for very short intervals only. 1243 // If the VMThread's priority is not lower than the WatcherThread profiling 1244 // will be inaccurate. 1245 os::set_priority(this, MaxPriority); 1246 if (!DisableStartThread) { 1247 os::start_thread(this); 1248 } 1249 } 1250} 1251 1252int WatcherThread::sleep() const { 1253 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1254 1255 // remaining will be zero if there are no tasks, 1256 // causing the WatcherThread to sleep until a task is 1257 // enrolled 1258 int remaining = PeriodicTask::time_to_wait(); 1259 int time_slept = 0; 1260 1261 // we expect this to timeout - we only ever get unparked when 1262 // we should terminate or when a new task has been enrolled 1263 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1264 1265 jlong time_before_loop = os::javaTimeNanos(); 1266 1267 for (;;) { 1268 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1269 jlong now = os::javaTimeNanos(); 1270 1271 if (remaining == 0) { 1272 // if we didn't have any tasks we could have waited for a long time 1273 // consider the time_slept zero and reset time_before_loop 1274 time_slept = 0; 1275 time_before_loop = now; 1276 } else { 1277 // need to recalculate since we might have new tasks in _tasks 1278 time_slept = (int) ((now - time_before_loop) / 1000000); 1279 } 1280 1281 // Change to task list or spurious wakeup of some kind 1282 if (timedout || _should_terminate) { 1283 break; 1284 } 1285 1286 remaining = PeriodicTask::time_to_wait(); 1287 if (remaining == 0) { 1288 // Last task was just disenrolled so loop around and wait until 1289 // another task gets enrolled 1290 continue; 1291 } 1292 1293 remaining -= time_slept; 1294 if (remaining <= 0) 1295 break; 1296 } 1297 1298 return time_slept; 1299} 1300 1301void WatcherThread::run() { 1302 assert(this == watcher_thread(), "just checking"); 1303 1304 this->record_stack_base_and_size(); 1305 this->initialize_thread_local_storage(); 1306 this->set_active_handles(JNIHandleBlock::allocate_block()); 1307 while(!_should_terminate) { 1308 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1309 assert(watcher_thread() == this, "thread consistency check"); 1310 1311 // Calculate how long it'll be until the next PeriodicTask work 1312 // should be done, and sleep that amount of time. 1313 int time_waited = sleep(); 1314 1315 if (is_error_reported()) { 1316 // A fatal error has happened, the error handler(VMError::report_and_die) 1317 // should abort JVM after creating an error log file. However in some 1318 // rare cases, the error handler itself might deadlock. Here we try to 1319 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1320 // 1321 // This code is in WatcherThread because WatcherThread wakes up 1322 // periodically so the fatal error handler doesn't need to do anything; 1323 // also because the WatcherThread is less likely to crash than other 1324 // threads. 1325 1326 for (;;) { 1327 if (!ShowMessageBoxOnError 1328 && (OnError == NULL || OnError[0] == '\0') 1329 && Arguments::abort_hook() == NULL) { 1330 os::sleep(this, 2 * 60 * 1000, false); 1331 fdStream err(defaultStream::output_fd()); 1332 err.print_raw_cr("# [ timer expired, abort... ]"); 1333 // skip atexit/vm_exit/vm_abort hooks 1334 os::die(); 1335 } 1336 1337 // Wake up 5 seconds later, the fatal handler may reset OnError or 1338 // ShowMessageBoxOnError when it is ready to abort. 1339 os::sleep(this, 5 * 1000, false); 1340 } 1341 } 1342 1343 PeriodicTask::real_time_tick(time_waited); 1344 } 1345 1346 // Signal that it is terminated 1347 { 1348 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1349 _watcher_thread = NULL; 1350 Terminator_lock->notify(); 1351 } 1352 1353 // Thread destructor usually does this.. 1354 ThreadLocalStorage::set_thread(NULL); 1355} 1356 1357void WatcherThread::start() { 1358 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1359 1360 if (watcher_thread() == NULL && _startable) { 1361 _should_terminate = false; 1362 // Create the single instance of WatcherThread 1363 new WatcherThread(); 1364 } 1365} 1366 1367void WatcherThread::make_startable() { 1368 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1369 _startable = true; 1370} 1371 1372void WatcherThread::stop() { 1373 { 1374 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1375 _should_terminate = true; 1376 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1377 1378 WatcherThread* watcher = watcher_thread(); 1379 if (watcher != NULL) 1380 watcher->unpark(); 1381 } 1382 1383 // it is ok to take late safepoints here, if needed 1384 MutexLocker mu(Terminator_lock); 1385 1386 while(watcher_thread() != NULL) { 1387 // This wait should make safepoint checks, wait without a timeout, 1388 // and wait as a suspend-equivalent condition. 1389 // 1390 // Note: If the FlatProfiler is running, then this thread is waiting 1391 // for the WatcherThread to terminate and the WatcherThread, via the 1392 // FlatProfiler task, is waiting for the external suspend request on 1393 // this thread to complete. wait_for_ext_suspend_completion() will 1394 // eventually timeout, but that takes time. Making this wait a 1395 // suspend-equivalent condition solves that timeout problem. 1396 // 1397 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1398 Mutex::_as_suspend_equivalent_flag); 1399 } 1400} 1401 1402void WatcherThread::unpark() { 1403 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1404 PeriodicTask_lock->notify(); 1405} 1406 1407void WatcherThread::print_on(outputStream* st) const { 1408 st->print("\"%s\" ", name()); 1409 Thread::print_on(st); 1410 st->cr(); 1411} 1412 1413// ======= JavaThread ======== 1414 1415// A JavaThread is a normal Java thread 1416 1417void JavaThread::initialize() { 1418 // Initialize fields 1419 1420 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1421 set_claimed_par_id(-1); 1422 1423 set_saved_exception_pc(NULL); 1424 set_threadObj(NULL); 1425 _anchor.clear(); 1426 set_entry_point(NULL); 1427 set_jni_functions(jni_functions()); 1428 set_callee_target(NULL); 1429 set_vm_result(NULL); 1430 set_vm_result_2(NULL); 1431 set_vframe_array_head(NULL); 1432 set_vframe_array_last(NULL); 1433 set_deferred_locals(NULL); 1434 set_deopt_mark(NULL); 1435 set_deopt_nmethod(NULL); 1436 clear_must_deopt_id(); 1437 set_monitor_chunks(NULL); 1438 set_next(NULL); 1439 set_thread_state(_thread_new); 1440#if INCLUDE_NMT 1441 set_recorder(NULL); 1442#endif 1443 _terminated = _not_terminated; 1444 _privileged_stack_top = NULL; 1445 _array_for_gc = NULL; 1446 _suspend_equivalent = false; 1447 _in_deopt_handler = 0; 1448 _doing_unsafe_access = false; 1449 _stack_guard_state = stack_guard_unused; 1450 (void)const_cast<oop&>(_exception_oop = NULL); 1451 _exception_pc = 0; 1452 _exception_handler_pc = 0; 1453 _is_method_handle_return = 0; 1454 _jvmti_thread_state= NULL; 1455 _should_post_on_exceptions_flag = JNI_FALSE; 1456 _jvmti_get_loaded_classes_closure = NULL; 1457 _interp_only_mode = 0; 1458 _special_runtime_exit_condition = _no_async_condition; 1459 _pending_async_exception = NULL; 1460 _thread_stat = NULL; 1461 _thread_stat = new ThreadStatistics(); 1462 _blocked_on_compilation = false; 1463 _jni_active_critical = 0; 1464 _do_not_unlock_if_synchronized = false; 1465 _cached_monitor_info = NULL; 1466 _parker = Parker::Allocate(this) ; 1467 1468#ifndef PRODUCT 1469 _jmp_ring_index = 0; 1470 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1471 record_jump(NULL, NULL, NULL, 0); 1472 } 1473#endif /* PRODUCT */ 1474 1475 set_thread_profiler(NULL); 1476 if (FlatProfiler::is_active()) { 1477 // This is where we would decide to either give each thread it's own profiler 1478 // or use one global one from FlatProfiler, 1479 // or up to some count of the number of profiled threads, etc. 1480 ThreadProfiler* pp = new ThreadProfiler(); 1481 pp->engage(); 1482 set_thread_profiler(pp); 1483 } 1484 1485 // Setup safepoint state info for this thread 1486 ThreadSafepointState::create(this); 1487 1488 debug_only(_java_call_counter = 0); 1489 1490 // JVMTI PopFrame support 1491 _popframe_condition = popframe_inactive; 1492 _popframe_preserved_args = NULL; 1493 _popframe_preserved_args_size = 0; 1494 1495 pd_initialize(); 1496} 1497 1498#if INCLUDE_ALL_GCS 1499SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1500DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1501#endif // INCLUDE_ALL_GCS 1502 1503JavaThread::JavaThread(bool is_attaching_via_jni) : 1504 Thread() 1505#if INCLUDE_ALL_GCS 1506 , _satb_mark_queue(&_satb_mark_queue_set), 1507 _dirty_card_queue(&_dirty_card_queue_set) 1508#endif // INCLUDE_ALL_GCS 1509{ 1510 initialize(); 1511 if (is_attaching_via_jni) { 1512 _jni_attach_state = _attaching_via_jni; 1513 } else { 1514 _jni_attach_state = _not_attaching_via_jni; 1515 } 1516 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1517 _safepoint_visible = false; 1518} 1519 1520bool JavaThread::reguard_stack(address cur_sp) { 1521 if (_stack_guard_state != stack_guard_yellow_disabled) { 1522 return true; // Stack already guarded or guard pages not needed. 1523 } 1524 1525 if (register_stack_overflow()) { 1526 // For those architectures which have separate register and 1527 // memory stacks, we must check the register stack to see if 1528 // it has overflowed. 1529 return false; 1530 } 1531 1532 // Java code never executes within the yellow zone: the latter is only 1533 // there to provoke an exception during stack banging. If java code 1534 // is executing there, either StackShadowPages should be larger, or 1535 // some exception code in c1, c2 or the interpreter isn't unwinding 1536 // when it should. 1537 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1538 1539 enable_stack_yellow_zone(); 1540 return true; 1541} 1542 1543bool JavaThread::reguard_stack(void) { 1544 return reguard_stack(os::current_stack_pointer()); 1545} 1546 1547 1548void JavaThread::block_if_vm_exited() { 1549 if (_terminated == _vm_exited) { 1550 // _vm_exited is set at safepoint, and Threads_lock is never released 1551 // we will block here forever 1552 Threads_lock->lock_without_safepoint_check(); 1553 ShouldNotReachHere(); 1554 } 1555} 1556 1557 1558// Remove this ifdef when C1 is ported to the compiler interface. 1559static void compiler_thread_entry(JavaThread* thread, TRAPS); 1560 1561JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1562 Thread() 1563#if INCLUDE_ALL_GCS 1564 , _satb_mark_queue(&_satb_mark_queue_set), 1565 _dirty_card_queue(&_dirty_card_queue_set) 1566#endif // INCLUDE_ALL_GCS 1567{ 1568 if (TraceThreadEvents) { 1569 tty->print_cr("creating thread %p", this); 1570 } 1571 initialize(); 1572 _jni_attach_state = _not_attaching_via_jni; 1573 set_entry_point(entry_point); 1574 // Create the native thread itself. 1575 // %note runtime_23 1576 os::ThreadType thr_type = os::java_thread; 1577 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1578 os::java_thread; 1579 os::create_thread(this, thr_type, stack_sz); 1580 _safepoint_visible = false; 1581 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1582 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1583 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1584 // the exception consists of creating the exception object & initializing it, initialization 1585 // will leave the VM via a JavaCall and then all locks must be unlocked). 1586 // 1587 // The thread is still suspended when we reach here. Thread must be explicit started 1588 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1589 // by calling Threads:add. The reason why this is not done here, is because the thread 1590 // object must be fully initialized (take a look at JVM_Start) 1591} 1592 1593JavaThread::~JavaThread() { 1594 if (TraceThreadEvents) { 1595 tty->print_cr("terminate thread %p", this); 1596 } 1597 1598 // By now, this thread should already be invisible to safepoint, 1599 // and its per-thread recorder also collected. 1600 assert(!is_safepoint_visible(), "wrong state"); 1601#if INCLUDE_NMT 1602 assert(get_recorder() == NULL, "Already collected"); 1603#endif // INCLUDE_NMT 1604 1605 // JSR166 -- return the parker to the free list 1606 Parker::Release(_parker); 1607 _parker = NULL ; 1608 1609 // Free any remaining previous UnrollBlock 1610 vframeArray* old_array = vframe_array_last(); 1611 1612 if (old_array != NULL) { 1613 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1614 old_array->set_unroll_block(NULL); 1615 delete old_info; 1616 delete old_array; 1617 } 1618 1619 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1620 if (deferred != NULL) { 1621 // This can only happen if thread is destroyed before deoptimization occurs. 1622 assert(deferred->length() != 0, "empty array!"); 1623 do { 1624 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1625 deferred->remove_at(0); 1626 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1627 delete dlv; 1628 } while (deferred->length() != 0); 1629 delete deferred; 1630 } 1631 1632 // All Java related clean up happens in exit 1633 ThreadSafepointState::destroy(this); 1634 if (_thread_profiler != NULL) delete _thread_profiler; 1635 if (_thread_stat != NULL) delete _thread_stat; 1636} 1637 1638 1639// The first routine called by a new Java thread 1640void JavaThread::run() { 1641 // initialize thread-local alloc buffer related fields 1642 this->initialize_tlab(); 1643 1644 // used to test validity of stack trace backs 1645 this->record_base_of_stack_pointer(); 1646 1647 // Record real stack base and size. 1648 this->record_stack_base_and_size(); 1649 1650 // Initialize thread local storage; set before calling MutexLocker 1651 this->initialize_thread_local_storage(); 1652 1653 this->create_stack_guard_pages(); 1654 1655 this->cache_global_variables(); 1656 1657 // Thread is now sufficient initialized to be handled by the safepoint code as being 1658 // in the VM. Change thread state from _thread_new to _thread_in_vm 1659 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1660 1661 assert(JavaThread::current() == this, "sanity check"); 1662 assert(!Thread::current()->owns_locks(), "sanity check"); 1663 1664 DTRACE_THREAD_PROBE(start, this); 1665 1666 // This operation might block. We call that after all safepoint checks for a new thread has 1667 // been completed. 1668 this->set_active_handles(JNIHandleBlock::allocate_block()); 1669 1670 if (JvmtiExport::should_post_thread_life()) { 1671 JvmtiExport::post_thread_start(this); 1672 } 1673 1674 EventThreadStart event; 1675 if (event.should_commit()) { 1676 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1677 event.commit(); 1678 } 1679 1680 // We call another function to do the rest so we are sure that the stack addresses used 1681 // from there will be lower than the stack base just computed 1682 thread_main_inner(); 1683 1684 // Note, thread is no longer valid at this point! 1685} 1686 1687 1688void JavaThread::thread_main_inner() { 1689 assert(JavaThread::current() == this, "sanity check"); 1690 assert(this->threadObj() != NULL, "just checking"); 1691 1692 // Execute thread entry point unless this thread has a pending exception 1693 // or has been stopped before starting. 1694 // Note: Due to JVM_StopThread we can have pending exceptions already! 1695 if (!this->has_pending_exception() && 1696 !java_lang_Thread::is_stillborn(this->threadObj())) { 1697 { 1698 ResourceMark rm(this); 1699 this->set_native_thread_name(this->get_thread_name()); 1700 } 1701 HandleMark hm(this); 1702 this->entry_point()(this, this); 1703 } 1704 1705 DTRACE_THREAD_PROBE(stop, this); 1706 1707 this->exit(false); 1708 delete this; 1709} 1710 1711 1712static void ensure_join(JavaThread* thread) { 1713 // We do not need to grap the Threads_lock, since we are operating on ourself. 1714 Handle threadObj(thread, thread->threadObj()); 1715 assert(threadObj.not_null(), "java thread object must exist"); 1716 ObjectLocker lock(threadObj, thread); 1717 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1718 thread->clear_pending_exception(); 1719 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1720 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1721 // Clear the native thread instance - this makes isAlive return false and allows the join() 1722 // to complete once we've done the notify_all below 1723 java_lang_Thread::set_thread(threadObj(), NULL); 1724 lock.notify_all(thread); 1725 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1726 thread->clear_pending_exception(); 1727} 1728 1729 1730// For any new cleanup additions, please check to see if they need to be applied to 1731// cleanup_failed_attach_current_thread as well. 1732void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1733 assert(this == JavaThread::current(), "thread consistency check"); 1734 1735 HandleMark hm(this); 1736 Handle uncaught_exception(this, this->pending_exception()); 1737 this->clear_pending_exception(); 1738 Handle threadObj(this, this->threadObj()); 1739 assert(threadObj.not_null(), "Java thread object should be created"); 1740 1741 if (get_thread_profiler() != NULL) { 1742 get_thread_profiler()->disengage(); 1743 ResourceMark rm; 1744 get_thread_profiler()->print(get_thread_name()); 1745 } 1746 1747 1748 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1749 { 1750 EXCEPTION_MARK; 1751 1752 CLEAR_PENDING_EXCEPTION; 1753 } 1754 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1755 // has to be fixed by a runtime query method 1756 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1757 // JSR-166: change call from from ThreadGroup.uncaughtException to 1758 // java.lang.Thread.dispatchUncaughtException 1759 if (uncaught_exception.not_null()) { 1760 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1761 { 1762 EXCEPTION_MARK; 1763 // Check if the method Thread.dispatchUncaughtException() exists. If so 1764 // call it. Otherwise we have an older library without the JSR-166 changes, 1765 // so call ThreadGroup.uncaughtException() 1766 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1767 CallInfo callinfo; 1768 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1769 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1770 vmSymbols::dispatchUncaughtException_name(), 1771 vmSymbols::throwable_void_signature(), 1772 KlassHandle(), false, false, THREAD); 1773 CLEAR_PENDING_EXCEPTION; 1774 methodHandle method = callinfo.selected_method(); 1775 if (method.not_null()) { 1776 JavaValue result(T_VOID); 1777 JavaCalls::call_virtual(&result, 1778 threadObj, thread_klass, 1779 vmSymbols::dispatchUncaughtException_name(), 1780 vmSymbols::throwable_void_signature(), 1781 uncaught_exception, 1782 THREAD); 1783 } else { 1784 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1785 JavaValue result(T_VOID); 1786 JavaCalls::call_virtual(&result, 1787 group, thread_group, 1788 vmSymbols::uncaughtException_name(), 1789 vmSymbols::thread_throwable_void_signature(), 1790 threadObj, // Arg 1 1791 uncaught_exception, // Arg 2 1792 THREAD); 1793 } 1794 if (HAS_PENDING_EXCEPTION) { 1795 ResourceMark rm(this); 1796 jio_fprintf(defaultStream::error_stream(), 1797 "\nException: %s thrown from the UncaughtExceptionHandler" 1798 " in thread \"%s\"\n", 1799 pending_exception()->klass()->external_name(), 1800 get_thread_name()); 1801 CLEAR_PENDING_EXCEPTION; 1802 } 1803 } 1804 } 1805 1806 // Called before the java thread exit since we want to read info 1807 // from java_lang_Thread object 1808 EventThreadEnd event; 1809 if (event.should_commit()) { 1810 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1811 event.commit(); 1812 } 1813 1814 // Call after last event on thread 1815 EVENT_THREAD_EXIT(this); 1816 1817 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1818 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1819 // is deprecated anyhow. 1820 if (!is_Compiler_thread()) { 1821 int count = 3; 1822 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1823 EXCEPTION_MARK; 1824 JavaValue result(T_VOID); 1825 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1826 JavaCalls::call_virtual(&result, 1827 threadObj, thread_klass, 1828 vmSymbols::exit_method_name(), 1829 vmSymbols::void_method_signature(), 1830 THREAD); 1831 CLEAR_PENDING_EXCEPTION; 1832 } 1833 } 1834 // notify JVMTI 1835 if (JvmtiExport::should_post_thread_life()) { 1836 JvmtiExport::post_thread_end(this); 1837 } 1838 1839 // We have notified the agents that we are exiting, before we go on, 1840 // we must check for a pending external suspend request and honor it 1841 // in order to not surprise the thread that made the suspend request. 1842 while (true) { 1843 { 1844 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1845 if (!is_external_suspend()) { 1846 set_terminated(_thread_exiting); 1847 ThreadService::current_thread_exiting(this); 1848 break; 1849 } 1850 // Implied else: 1851 // Things get a little tricky here. We have a pending external 1852 // suspend request, but we are holding the SR_lock so we 1853 // can't just self-suspend. So we temporarily drop the lock 1854 // and then self-suspend. 1855 } 1856 1857 ThreadBlockInVM tbivm(this); 1858 java_suspend_self(); 1859 1860 // We're done with this suspend request, but we have to loop around 1861 // and check again. Eventually we will get SR_lock without a pending 1862 // external suspend request and will be able to mark ourselves as 1863 // exiting. 1864 } 1865 // no more external suspends are allowed at this point 1866 } else { 1867 // before_exit() has already posted JVMTI THREAD_END events 1868 } 1869 1870 // Notify waiters on thread object. This has to be done after exit() is called 1871 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1872 // group should have the destroyed bit set before waiters are notified). 1873 ensure_join(this); 1874 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1875 1876 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1877 // held by this thread must be released. A detach operation must only 1878 // get here if there are no Java frames on the stack. Therefore, any 1879 // owned monitors at this point MUST be JNI-acquired monitors which are 1880 // pre-inflated and in the monitor cache. 1881 // 1882 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1883 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1884 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1885 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1886 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1887 } 1888 1889 // These things needs to be done while we are still a Java Thread. Make sure that thread 1890 // is in a consistent state, in case GC happens 1891 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1892 1893 if (active_handles() != NULL) { 1894 JNIHandleBlock* block = active_handles(); 1895 set_active_handles(NULL); 1896 JNIHandleBlock::release_block(block); 1897 } 1898 1899 if (free_handle_block() != NULL) { 1900 JNIHandleBlock* block = free_handle_block(); 1901 set_free_handle_block(NULL); 1902 JNIHandleBlock::release_block(block); 1903 } 1904 1905 // These have to be removed while this is still a valid thread. 1906 remove_stack_guard_pages(); 1907 1908 if (UseTLAB) { 1909 tlab().make_parsable(true); // retire TLAB 1910 } 1911 1912 if (JvmtiEnv::environments_might_exist()) { 1913 JvmtiExport::cleanup_thread(this); 1914 } 1915 1916 // We must flush any deferred card marks before removing a thread from 1917 // the list of active threads. 1918 Universe::heap()->flush_deferred_store_barrier(this); 1919 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1920 1921#if INCLUDE_ALL_GCS 1922 // We must flush the G1-related buffers before removing a thread 1923 // from the list of active threads. We must do this after any deferred 1924 // card marks have been flushed (above) so that any entries that are 1925 // added to the thread's dirty card queue as a result are not lost. 1926 if (UseG1GC) { 1927 flush_barrier_queues(); 1928 } 1929#endif // INCLUDE_ALL_GCS 1930 1931 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1932 Threads::remove(this); 1933} 1934 1935#if INCLUDE_ALL_GCS 1936// Flush G1-related queues. 1937void JavaThread::flush_barrier_queues() { 1938 satb_mark_queue().flush(); 1939 dirty_card_queue().flush(); 1940} 1941 1942void JavaThread::initialize_queues() { 1943 assert(!SafepointSynchronize::is_at_safepoint(), 1944 "we should not be at a safepoint"); 1945 1946 ObjPtrQueue& satb_queue = satb_mark_queue(); 1947 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1948 // The SATB queue should have been constructed with its active 1949 // field set to false. 1950 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1951 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1952 // If we are creating the thread during a marking cycle, we should 1953 // set the active field of the SATB queue to true. 1954 if (satb_queue_set.is_active()) { 1955 satb_queue.set_active(true); 1956 } 1957 1958 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1959 // The dirty card queue should have been constructed with its 1960 // active field set to true. 1961 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1962} 1963#endif // INCLUDE_ALL_GCS 1964 1965void JavaThread::cleanup_failed_attach_current_thread() { 1966 if (get_thread_profiler() != NULL) { 1967 get_thread_profiler()->disengage(); 1968 ResourceMark rm; 1969 get_thread_profiler()->print(get_thread_name()); 1970 } 1971 1972 if (active_handles() != NULL) { 1973 JNIHandleBlock* block = active_handles(); 1974 set_active_handles(NULL); 1975 JNIHandleBlock::release_block(block); 1976 } 1977 1978 if (free_handle_block() != NULL) { 1979 JNIHandleBlock* block = free_handle_block(); 1980 set_free_handle_block(NULL); 1981 JNIHandleBlock::release_block(block); 1982 } 1983 1984 // These have to be removed while this is still a valid thread. 1985 remove_stack_guard_pages(); 1986 1987 if (UseTLAB) { 1988 tlab().make_parsable(true); // retire TLAB, if any 1989 } 1990 1991#if INCLUDE_ALL_GCS 1992 if (UseG1GC) { 1993 flush_barrier_queues(); 1994 } 1995#endif // INCLUDE_ALL_GCS 1996 1997 Threads::remove(this); 1998 delete this; 1999} 2000 2001 2002 2003 2004JavaThread* JavaThread::active() { 2005 Thread* thread = ThreadLocalStorage::thread(); 2006 assert(thread != NULL, "just checking"); 2007 if (thread->is_Java_thread()) { 2008 return (JavaThread*) thread; 2009 } else { 2010 assert(thread->is_VM_thread(), "this must be a vm thread"); 2011 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2012 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2013 assert(ret->is_Java_thread(), "must be a Java thread"); 2014 return ret; 2015 } 2016} 2017 2018bool JavaThread::is_lock_owned(address adr) const { 2019 if (Thread::is_lock_owned(adr)) return true; 2020 2021 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2022 if (chunk->contains(adr)) return true; 2023 } 2024 2025 return false; 2026} 2027 2028 2029void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2030 chunk->set_next(monitor_chunks()); 2031 set_monitor_chunks(chunk); 2032} 2033 2034void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2035 guarantee(monitor_chunks() != NULL, "must be non empty"); 2036 if (monitor_chunks() == chunk) { 2037 set_monitor_chunks(chunk->next()); 2038 } else { 2039 MonitorChunk* prev = monitor_chunks(); 2040 while (prev->next() != chunk) prev = prev->next(); 2041 prev->set_next(chunk->next()); 2042 } 2043} 2044 2045// JVM support. 2046 2047// Note: this function shouldn't block if it's called in 2048// _thread_in_native_trans state (such as from 2049// check_special_condition_for_native_trans()). 2050void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2051 2052 if (has_last_Java_frame() && has_async_condition()) { 2053 // If we are at a polling page safepoint (not a poll return) 2054 // then we must defer async exception because live registers 2055 // will be clobbered by the exception path. Poll return is 2056 // ok because the call we a returning from already collides 2057 // with exception handling registers and so there is no issue. 2058 // (The exception handling path kills call result registers but 2059 // this is ok since the exception kills the result anyway). 2060 2061 if (is_at_poll_safepoint()) { 2062 // if the code we are returning to has deoptimized we must defer 2063 // the exception otherwise live registers get clobbered on the 2064 // exception path before deoptimization is able to retrieve them. 2065 // 2066 RegisterMap map(this, false); 2067 frame caller_fr = last_frame().sender(&map); 2068 assert(caller_fr.is_compiled_frame(), "what?"); 2069 if (caller_fr.is_deoptimized_frame()) { 2070 if (TraceExceptions) { 2071 ResourceMark rm; 2072 tty->print_cr("deferred async exception at compiled safepoint"); 2073 } 2074 return; 2075 } 2076 } 2077 } 2078 2079 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2080 if (condition == _no_async_condition) { 2081 // Conditions have changed since has_special_runtime_exit_condition() 2082 // was called: 2083 // - if we were here only because of an external suspend request, 2084 // then that was taken care of above (or cancelled) so we are done 2085 // - if we were here because of another async request, then it has 2086 // been cleared between the has_special_runtime_exit_condition() 2087 // and now so again we are done 2088 return; 2089 } 2090 2091 // Check for pending async. exception 2092 if (_pending_async_exception != NULL) { 2093 // Only overwrite an already pending exception, if it is not a threadDeath. 2094 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2095 2096 // We cannot call Exceptions::_throw(...) here because we cannot block 2097 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2098 2099 if (TraceExceptions) { 2100 ResourceMark rm; 2101 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2102 if (has_last_Java_frame() ) { 2103 frame f = last_frame(); 2104 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2105 } 2106 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2107 } 2108 _pending_async_exception = NULL; 2109 clear_has_async_exception(); 2110 } 2111 } 2112 2113 if (check_unsafe_error && 2114 condition == _async_unsafe_access_error && !has_pending_exception()) { 2115 condition = _no_async_condition; // done 2116 switch (thread_state()) { 2117 case _thread_in_vm: 2118 { 2119 JavaThread* THREAD = this; 2120 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2121 } 2122 case _thread_in_native: 2123 { 2124 ThreadInVMfromNative tiv(this); 2125 JavaThread* THREAD = this; 2126 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2127 } 2128 case _thread_in_Java: 2129 { 2130 ThreadInVMfromJava tiv(this); 2131 JavaThread* THREAD = this; 2132 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2133 } 2134 default: 2135 ShouldNotReachHere(); 2136 } 2137 } 2138 2139 assert(condition == _no_async_condition || has_pending_exception() || 2140 (!check_unsafe_error && condition == _async_unsafe_access_error), 2141 "must have handled the async condition, if no exception"); 2142} 2143 2144void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2145 // 2146 // Check for pending external suspend. Internal suspend requests do 2147 // not use handle_special_runtime_exit_condition(). 2148 // If JNIEnv proxies are allowed, don't self-suspend if the target 2149 // thread is not the current thread. In older versions of jdbx, jdbx 2150 // threads could call into the VM with another thread's JNIEnv so we 2151 // can be here operating on behalf of a suspended thread (4432884). 2152 bool do_self_suspend = is_external_suspend_with_lock(); 2153 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2154 // 2155 // Because thread is external suspended the safepoint code will count 2156 // thread as at a safepoint. This can be odd because we can be here 2157 // as _thread_in_Java which would normally transition to _thread_blocked 2158 // at a safepoint. We would like to mark the thread as _thread_blocked 2159 // before calling java_suspend_self like all other callers of it but 2160 // we must then observe proper safepoint protocol. (We can't leave 2161 // _thread_blocked with a safepoint in progress). However we can be 2162 // here as _thread_in_native_trans so we can't use a normal transition 2163 // constructor/destructor pair because they assert on that type of 2164 // transition. We could do something like: 2165 // 2166 // JavaThreadState state = thread_state(); 2167 // set_thread_state(_thread_in_vm); 2168 // { 2169 // ThreadBlockInVM tbivm(this); 2170 // java_suspend_self() 2171 // } 2172 // set_thread_state(_thread_in_vm_trans); 2173 // if (safepoint) block; 2174 // set_thread_state(state); 2175 // 2176 // but that is pretty messy. Instead we just go with the way the 2177 // code has worked before and note that this is the only path to 2178 // java_suspend_self that doesn't put the thread in _thread_blocked 2179 // mode. 2180 2181 frame_anchor()->make_walkable(this); 2182 java_suspend_self(); 2183 2184 // We might be here for reasons in addition to the self-suspend request 2185 // so check for other async requests. 2186 } 2187 2188 if (check_asyncs) { 2189 check_and_handle_async_exceptions(); 2190 } 2191} 2192 2193void JavaThread::send_thread_stop(oop java_throwable) { 2194 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2195 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2196 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2197 2198 // Do not throw asynchronous exceptions against the compiler thread 2199 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2200 if (is_Compiler_thread()) return; 2201 2202 { 2203 // Actually throw the Throwable against the target Thread - however 2204 // only if there is no thread death exception installed already. 2205 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2206 // If the topmost frame is a runtime stub, then we are calling into 2207 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2208 // must deoptimize the caller before continuing, as the compiled exception handler table 2209 // may not be valid 2210 if (has_last_Java_frame()) { 2211 frame f = last_frame(); 2212 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2213 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2214 RegisterMap reg_map(this, UseBiasedLocking); 2215 frame compiled_frame = f.sender(®_map); 2216 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2217 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2218 } 2219 } 2220 } 2221 2222 // Set async. pending exception in thread. 2223 set_pending_async_exception(java_throwable); 2224 2225 if (TraceExceptions) { 2226 ResourceMark rm; 2227 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2228 } 2229 // for AbortVMOnException flag 2230 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2231 } 2232 } 2233 2234 2235 // Interrupt thread so it will wake up from a potential wait() 2236 Thread::interrupt(this); 2237} 2238 2239// External suspension mechanism. 2240// 2241// Tell the VM to suspend a thread when ever it knows that it does not hold on 2242// to any VM_locks and it is at a transition 2243// Self-suspension will happen on the transition out of the vm. 2244// Catch "this" coming in from JNIEnv pointers when the thread has been freed 2245// 2246// Guarantees on return: 2247// + Target thread will not execute any new bytecode (that's why we need to 2248// force a safepoint) 2249// + Target thread will not enter any new monitors 2250// 2251void JavaThread::java_suspend() { 2252 { MutexLocker mu(Threads_lock); 2253 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2254 return; 2255 } 2256 } 2257 2258 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2259 if (!is_external_suspend()) { 2260 // a racing resume has cancelled us; bail out now 2261 return; 2262 } 2263 2264 // suspend is done 2265 uint32_t debug_bits = 0; 2266 // Warning: is_ext_suspend_completed() may temporarily drop the 2267 // SR_lock to allow the thread to reach a stable thread state if 2268 // it is currently in a transient thread state. 2269 if (is_ext_suspend_completed(false /* !called_by_wait */, 2270 SuspendRetryDelay, &debug_bits) ) { 2271 return; 2272 } 2273 } 2274 2275 VM_ForceSafepoint vm_suspend; 2276 VMThread::execute(&vm_suspend); 2277} 2278 2279// Part II of external suspension. 2280// A JavaThread self suspends when it detects a pending external suspend 2281// request. This is usually on transitions. It is also done in places 2282// where continuing to the next transition would surprise the caller, 2283// e.g., monitor entry. 2284// 2285// Returns the number of times that the thread self-suspended. 2286// 2287// Note: DO NOT call java_suspend_self() when you just want to block current 2288// thread. java_suspend_self() is the second stage of cooperative 2289// suspension for external suspend requests and should only be used 2290// to complete an external suspend request. 2291// 2292int JavaThread::java_suspend_self() { 2293 int ret = 0; 2294 2295 // we are in the process of exiting so don't suspend 2296 if (is_exiting()) { 2297 clear_external_suspend(); 2298 return ret; 2299 } 2300 2301 assert(_anchor.walkable() || 2302 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2303 "must have walkable stack"); 2304 2305 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2306 2307 assert(!this->is_ext_suspended(), 2308 "a thread trying to self-suspend should not already be suspended"); 2309 2310 if (this->is_suspend_equivalent()) { 2311 // If we are self-suspending as a result of the lifting of a 2312 // suspend equivalent condition, then the suspend_equivalent 2313 // flag is not cleared until we set the ext_suspended flag so 2314 // that wait_for_ext_suspend_completion() returns consistent 2315 // results. 2316 this->clear_suspend_equivalent(); 2317 } 2318 2319 // A racing resume may have cancelled us before we grabbed SR_lock 2320 // above. Or another external suspend request could be waiting for us 2321 // by the time we return from SR_lock()->wait(). The thread 2322 // that requested the suspension may already be trying to walk our 2323 // stack and if we return now, we can change the stack out from under 2324 // it. This would be a "bad thing (TM)" and cause the stack walker 2325 // to crash. We stay self-suspended until there are no more pending 2326 // external suspend requests. 2327 while (is_external_suspend()) { 2328 ret++; 2329 this->set_ext_suspended(); 2330 2331 // _ext_suspended flag is cleared by java_resume() 2332 while (is_ext_suspended()) { 2333 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2334 } 2335 } 2336 2337 return ret; 2338} 2339 2340#ifdef ASSERT 2341// verify the JavaThread has not yet been published in the Threads::list, and 2342// hence doesn't need protection from concurrent access at this stage 2343void JavaThread::verify_not_published() { 2344 if (!Threads_lock->owned_by_self()) { 2345 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2346 assert( !Threads::includes(this), 2347 "java thread shouldn't have been published yet!"); 2348 } 2349 else { 2350 assert( !Threads::includes(this), 2351 "java thread shouldn't have been published yet!"); 2352 } 2353} 2354#endif 2355 2356// Slow path when the native==>VM/Java barriers detect a safepoint is in 2357// progress or when _suspend_flags is non-zero. 2358// Current thread needs to self-suspend if there is a suspend request and/or 2359// block if a safepoint is in progress. 2360// Async exception ISN'T checked. 2361// Note only the ThreadInVMfromNative transition can call this function 2362// directly and when thread state is _thread_in_native_trans 2363void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2364 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2365 2366 JavaThread *curJT = JavaThread::current(); 2367 bool do_self_suspend = thread->is_external_suspend(); 2368 2369 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2370 2371 // If JNIEnv proxies are allowed, don't self-suspend if the target 2372 // thread is not the current thread. In older versions of jdbx, jdbx 2373 // threads could call into the VM with another thread's JNIEnv so we 2374 // can be here operating on behalf of a suspended thread (4432884). 2375 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2376 JavaThreadState state = thread->thread_state(); 2377 2378 // We mark this thread_blocked state as a suspend-equivalent so 2379 // that a caller to is_ext_suspend_completed() won't be confused. 2380 // The suspend-equivalent state is cleared by java_suspend_self(). 2381 thread->set_suspend_equivalent(); 2382 2383 // If the safepoint code sees the _thread_in_native_trans state, it will 2384 // wait until the thread changes to other thread state. There is no 2385 // guarantee on how soon we can obtain the SR_lock and complete the 2386 // self-suspend request. It would be a bad idea to let safepoint wait for 2387 // too long. Temporarily change the state to _thread_blocked to 2388 // let the VM thread know that this thread is ready for GC. The problem 2389 // of changing thread state is that safepoint could happen just after 2390 // java_suspend_self() returns after being resumed, and VM thread will 2391 // see the _thread_blocked state. We must check for safepoint 2392 // after restoring the state and make sure we won't leave while a safepoint 2393 // is in progress. 2394 thread->set_thread_state(_thread_blocked); 2395 thread->java_suspend_self(); 2396 thread->set_thread_state(state); 2397 // Make sure new state is seen by VM thread 2398 if (os::is_MP()) { 2399 if (UseMembar) { 2400 // Force a fence between the write above and read below 2401 OrderAccess::fence(); 2402 } else { 2403 // Must use this rather than serialization page in particular on Windows 2404 InterfaceSupport::serialize_memory(thread); 2405 } 2406 } 2407 } 2408 2409 if (SafepointSynchronize::do_call_back()) { 2410 // If we are safepointing, then block the caller which may not be 2411 // the same as the target thread (see above). 2412 SafepointSynchronize::block(curJT); 2413 } 2414 2415 if (thread->is_deopt_suspend()) { 2416 thread->clear_deopt_suspend(); 2417 RegisterMap map(thread, false); 2418 frame f = thread->last_frame(); 2419 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2420 f = f.sender(&map); 2421 } 2422 if (f.id() == thread->must_deopt_id()) { 2423 thread->clear_must_deopt_id(); 2424 f.deoptimize(thread); 2425 } else { 2426 fatal("missed deoptimization!"); 2427 } 2428 } 2429} 2430 2431// Slow path when the native==>VM/Java barriers detect a safepoint is in 2432// progress or when _suspend_flags is non-zero. 2433// Current thread needs to self-suspend if there is a suspend request and/or 2434// block if a safepoint is in progress. 2435// Also check for pending async exception (not including unsafe access error). 2436// Note only the native==>VM/Java barriers can call this function and when 2437// thread state is _thread_in_native_trans. 2438void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2439 check_safepoint_and_suspend_for_native_trans(thread); 2440 2441 if (thread->has_async_exception()) { 2442 // We are in _thread_in_native_trans state, don't handle unsafe 2443 // access error since that may block. 2444 thread->check_and_handle_async_exceptions(false); 2445 } 2446} 2447 2448// This is a variant of the normal 2449// check_special_condition_for_native_trans with slightly different 2450// semantics for use by critical native wrappers. It does all the 2451// normal checks but also performs the transition back into 2452// thread_in_Java state. This is required so that critical natives 2453// can potentially block and perform a GC if they are the last thread 2454// exiting the GC_locker. 2455void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2456 check_special_condition_for_native_trans(thread); 2457 2458 // Finish the transition 2459 thread->set_thread_state(_thread_in_Java); 2460 2461 if (thread->do_critical_native_unlock()) { 2462 ThreadInVMfromJavaNoAsyncException tiv(thread); 2463 GC_locker::unlock_critical(thread); 2464 thread->clear_critical_native_unlock(); 2465 } 2466} 2467 2468// We need to guarantee the Threads_lock here, since resumes are not 2469// allowed during safepoint synchronization 2470// Can only resume from an external suspension 2471void JavaThread::java_resume() { 2472 assert_locked_or_safepoint(Threads_lock); 2473 2474 // Sanity check: thread is gone, has started exiting or the thread 2475 // was not externally suspended. 2476 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2477 return; 2478 } 2479 2480 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2481 2482 clear_external_suspend(); 2483 2484 if (is_ext_suspended()) { 2485 clear_ext_suspended(); 2486 SR_lock()->notify_all(); 2487 } 2488} 2489 2490void JavaThread::create_stack_guard_pages() { 2491 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2492 address low_addr = stack_base() - stack_size(); 2493 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2494 2495 int allocate = os::allocate_stack_guard_pages(); 2496 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2497 2498 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2499 warning("Attempt to allocate stack guard pages failed."); 2500 return; 2501 } 2502 2503 if (os::guard_memory((char *) low_addr, len)) { 2504 _stack_guard_state = stack_guard_enabled; 2505 } else { 2506 warning("Attempt to protect stack guard pages failed."); 2507 if (os::uncommit_memory((char *) low_addr, len)) { 2508 warning("Attempt to deallocate stack guard pages failed."); 2509 } 2510 } 2511} 2512 2513void JavaThread::remove_stack_guard_pages() { 2514 assert(Thread::current() == this, "from different thread"); 2515 if (_stack_guard_state == stack_guard_unused) return; 2516 address low_addr = stack_base() - stack_size(); 2517 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2518 2519 if (os::allocate_stack_guard_pages()) { 2520 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2521 _stack_guard_state = stack_guard_unused; 2522 } else { 2523 warning("Attempt to deallocate stack guard pages failed."); 2524 } 2525 } else { 2526 if (_stack_guard_state == stack_guard_unused) return; 2527 if (os::unguard_memory((char *) low_addr, len)) { 2528 _stack_guard_state = stack_guard_unused; 2529 } else { 2530 warning("Attempt to unprotect stack guard pages failed."); 2531 } 2532 } 2533} 2534 2535void JavaThread::enable_stack_yellow_zone() { 2536 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2537 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2538 2539 // The base notation is from the stacks point of view, growing downward. 2540 // We need to adjust it to work correctly with guard_memory() 2541 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2542 2543 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2544 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2545 2546 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2547 _stack_guard_state = stack_guard_enabled; 2548 } else { 2549 warning("Attempt to guard stack yellow zone failed."); 2550 } 2551 enable_register_stack_guard(); 2552} 2553 2554void JavaThread::disable_stack_yellow_zone() { 2555 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2556 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2557 2558 // Simply return if called for a thread that does not use guard pages. 2559 if (_stack_guard_state == stack_guard_unused) return; 2560 2561 // The base notation is from the stacks point of view, growing downward. 2562 // We need to adjust it to work correctly with guard_memory() 2563 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2564 2565 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2566 _stack_guard_state = stack_guard_yellow_disabled; 2567 } else { 2568 warning("Attempt to unguard stack yellow zone failed."); 2569 } 2570 disable_register_stack_guard(); 2571} 2572 2573void JavaThread::enable_stack_red_zone() { 2574 // The base notation is from the stacks point of view, growing downward. 2575 // We need to adjust it to work correctly with guard_memory() 2576 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2577 address base = stack_red_zone_base() - stack_red_zone_size(); 2578 2579 guarantee(base < stack_base(),"Error calculating stack red zone"); 2580 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2581 2582 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2583 warning("Attempt to guard stack red zone failed."); 2584 } 2585} 2586 2587void JavaThread::disable_stack_red_zone() { 2588 // The base notation is from the stacks point of view, growing downward. 2589 // We need to adjust it to work correctly with guard_memory() 2590 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2591 address base = stack_red_zone_base() - stack_red_zone_size(); 2592 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2593 warning("Attempt to unguard stack red zone failed."); 2594 } 2595} 2596 2597void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2598 // ignore is there is no stack 2599 if (!has_last_Java_frame()) return; 2600 // traverse the stack frames. Starts from top frame. 2601 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2602 frame* fr = fst.current(); 2603 f(fr, fst.register_map()); 2604 } 2605} 2606 2607 2608#ifndef PRODUCT 2609// Deoptimization 2610// Function for testing deoptimization 2611void JavaThread::deoptimize() { 2612 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2613 StackFrameStream fst(this, UseBiasedLocking); 2614 bool deopt = false; // Dump stack only if a deopt actually happens. 2615 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2616 // Iterate over all frames in the thread and deoptimize 2617 for(; !fst.is_done(); fst.next()) { 2618 if(fst.current()->can_be_deoptimized()) { 2619 2620 if (only_at) { 2621 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2622 // consists of comma or carriage return separated numbers so 2623 // search for the current bci in that string. 2624 address pc = fst.current()->pc(); 2625 nmethod* nm = (nmethod*) fst.current()->cb(); 2626 ScopeDesc* sd = nm->scope_desc_at( pc); 2627 char buffer[8]; 2628 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2629 size_t len = strlen(buffer); 2630 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2631 while (found != NULL) { 2632 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2633 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2634 // Check that the bci found is bracketed by terminators. 2635 break; 2636 } 2637 found = strstr(found + 1, buffer); 2638 } 2639 if (!found) { 2640 continue; 2641 } 2642 } 2643 2644 if (DebugDeoptimization && !deopt) { 2645 deopt = true; // One-time only print before deopt 2646 tty->print_cr("[BEFORE Deoptimization]"); 2647 trace_frames(); 2648 trace_stack(); 2649 } 2650 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2651 } 2652 } 2653 2654 if (DebugDeoptimization && deopt) { 2655 tty->print_cr("[AFTER Deoptimization]"); 2656 trace_frames(); 2657 } 2658} 2659 2660 2661// Make zombies 2662void JavaThread::make_zombies() { 2663 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2664 if (fst.current()->can_be_deoptimized()) { 2665 // it is a Java nmethod 2666 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2667 nm->make_not_entrant(); 2668 } 2669 } 2670} 2671#endif // PRODUCT 2672 2673 2674void JavaThread::deoptimized_wrt_marked_nmethods() { 2675 if (!has_last_Java_frame()) return; 2676 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2677 StackFrameStream fst(this, UseBiasedLocking); 2678 for(; !fst.is_done(); fst.next()) { 2679 if (fst.current()->should_be_deoptimized()) { 2680 if (LogCompilation && xtty != NULL) { 2681 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2682 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2683 this->name(), nm != NULL ? nm->compile_id() : -1); 2684 } 2685 2686 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2687 } 2688 } 2689} 2690 2691 2692// GC support 2693static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2694 2695void JavaThread::gc_epilogue() { 2696 frames_do(frame_gc_epilogue); 2697} 2698 2699 2700static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2701 2702void JavaThread::gc_prologue() { 2703 frames_do(frame_gc_prologue); 2704} 2705 2706// If the caller is a NamedThread, then remember, in the current scope, 2707// the given JavaThread in its _processed_thread field. 2708class RememberProcessedThread: public StackObj { 2709 NamedThread* _cur_thr; 2710public: 2711 RememberProcessedThread(JavaThread* jthr) { 2712 Thread* thread = Thread::current(); 2713 if (thread->is_Named_thread()) { 2714 _cur_thr = (NamedThread *)thread; 2715 _cur_thr->set_processed_thread(jthr); 2716 } else { 2717 _cur_thr = NULL; 2718 } 2719 } 2720 2721 ~RememberProcessedThread() { 2722 if (_cur_thr) { 2723 _cur_thr->set_processed_thread(NULL); 2724 } 2725 } 2726}; 2727 2728void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 2729 // Verify that the deferred card marks have been flushed. 2730 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2731 2732 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2733 // since there may be more than one thread using each ThreadProfiler. 2734 2735 // Traverse the GCHandles 2736 Thread::oops_do(f, cld_f, cf); 2737 2738 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2739 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2740 2741 if (has_last_Java_frame()) { 2742 // Record JavaThread to GC thread 2743 RememberProcessedThread rpt(this); 2744 2745 // Traverse the privileged stack 2746 if (_privileged_stack_top != NULL) { 2747 _privileged_stack_top->oops_do(f); 2748 } 2749 2750 // traverse the registered growable array 2751 if (_array_for_gc != NULL) { 2752 for (int index = 0; index < _array_for_gc->length(); index++) { 2753 f->do_oop(_array_for_gc->adr_at(index)); 2754 } 2755 } 2756 2757 // Traverse the monitor chunks 2758 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2759 chunk->oops_do(f); 2760 } 2761 2762 // Traverse the execution stack 2763 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2764 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2765 } 2766 } 2767 2768 // callee_target is never live across a gc point so NULL it here should 2769 // it still contain a methdOop. 2770 2771 set_callee_target(NULL); 2772 2773 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2774 // If we have deferred set_locals there might be oops waiting to be 2775 // written 2776 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2777 if (list != NULL) { 2778 for (int i = 0; i < list->length(); i++) { 2779 list->at(i)->oops_do(f); 2780 } 2781 } 2782 2783 // Traverse instance variables at the end since the GC may be moving things 2784 // around using this function 2785 f->do_oop((oop*) &_threadObj); 2786 f->do_oop((oop*) &_vm_result); 2787 f->do_oop((oop*) &_exception_oop); 2788 f->do_oop((oop*) &_pending_async_exception); 2789 2790 if (jvmti_thread_state() != NULL) { 2791 jvmti_thread_state()->oops_do(f); 2792 } 2793} 2794 2795void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2796 Thread::nmethods_do(cf); // (super method is a no-op) 2797 2798 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2799 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2800 2801 if (has_last_Java_frame()) { 2802 // Traverse the execution stack 2803 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2804 fst.current()->nmethods_do(cf); 2805 } 2806 } 2807} 2808 2809void JavaThread::metadata_do(void f(Metadata*)) { 2810 Thread::metadata_do(f); 2811 if (has_last_Java_frame()) { 2812 // Traverse the execution stack to call f() on the methods in the stack 2813 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2814 fst.current()->metadata_do(f); 2815 } 2816 } else if (is_Compiler_thread()) { 2817 // need to walk ciMetadata in current compile tasks to keep alive. 2818 CompilerThread* ct = (CompilerThread*)this; 2819 if (ct->env() != NULL) { 2820 ct->env()->metadata_do(f); 2821 } 2822 } 2823} 2824 2825// Printing 2826const char* _get_thread_state_name(JavaThreadState _thread_state) { 2827 switch (_thread_state) { 2828 case _thread_uninitialized: return "_thread_uninitialized"; 2829 case _thread_new: return "_thread_new"; 2830 case _thread_new_trans: return "_thread_new_trans"; 2831 case _thread_in_native: return "_thread_in_native"; 2832 case _thread_in_native_trans: return "_thread_in_native_trans"; 2833 case _thread_in_vm: return "_thread_in_vm"; 2834 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2835 case _thread_in_Java: return "_thread_in_Java"; 2836 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2837 case _thread_blocked: return "_thread_blocked"; 2838 case _thread_blocked_trans: return "_thread_blocked_trans"; 2839 default: return "unknown thread state"; 2840 } 2841} 2842 2843#ifndef PRODUCT 2844void JavaThread::print_thread_state_on(outputStream *st) const { 2845 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2846}; 2847void JavaThread::print_thread_state() const { 2848 print_thread_state_on(tty); 2849}; 2850#endif // PRODUCT 2851 2852// Called by Threads::print() for VM_PrintThreads operation 2853void JavaThread::print_on(outputStream *st) const { 2854 st->print("\"%s\" ", get_thread_name()); 2855 oop thread_oop = threadObj(); 2856 if (thread_oop != NULL) { 2857 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2858 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2859 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2860 } 2861 Thread::print_on(st); 2862 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2863 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2864 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2865 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2866 } 2867#ifndef PRODUCT 2868 print_thread_state_on(st); 2869 _safepoint_state->print_on(st); 2870#endif // PRODUCT 2871} 2872 2873// Called by fatal error handler. The difference between this and 2874// JavaThread::print() is that we can't grab lock or allocate memory. 2875void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2876 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2877 oop thread_obj = threadObj(); 2878 if (thread_obj != NULL) { 2879 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2880 } 2881 st->print(" ["); 2882 st->print("%s", _get_thread_state_name(_thread_state)); 2883 if (osthread()) { 2884 st->print(", id=%d", osthread()->thread_id()); 2885 } 2886 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2887 _stack_base - _stack_size, _stack_base); 2888 st->print("]"); 2889 return; 2890} 2891 2892// Verification 2893 2894static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2895 2896void JavaThread::verify() { 2897 // Verify oops in the thread. 2898 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2899 2900 // Verify the stack frames. 2901 frames_do(frame_verify); 2902} 2903 2904// CR 6300358 (sub-CR 2137150) 2905// Most callers of this method assume that it can't return NULL but a 2906// thread may not have a name whilst it is in the process of attaching to 2907// the VM - see CR 6412693, and there are places where a JavaThread can be 2908// seen prior to having it's threadObj set (eg JNI attaching threads and 2909// if vm exit occurs during initialization). These cases can all be accounted 2910// for such that this method never returns NULL. 2911const char* JavaThread::get_thread_name() const { 2912#ifdef ASSERT 2913 // early safepoints can hit while current thread does not yet have TLS 2914 if (!SafepointSynchronize::is_at_safepoint()) { 2915 Thread *cur = Thread::current(); 2916 if (!(cur->is_Java_thread() && cur == this)) { 2917 // Current JavaThreads are allowed to get their own name without 2918 // the Threads_lock. 2919 assert_locked_or_safepoint(Threads_lock); 2920 } 2921 } 2922#endif // ASSERT 2923 return get_thread_name_string(); 2924} 2925 2926// Returns a non-NULL representation of this thread's name, or a suitable 2927// descriptive string if there is no set name 2928const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2929 const char* name_str; 2930 oop thread_obj = threadObj(); 2931 if (thread_obj != NULL) { 2932 typeArrayOop name = java_lang_Thread::name(thread_obj); 2933 if (name != NULL) { 2934 if (buf == NULL) { 2935 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2936 } 2937 else { 2938 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2939 } 2940 } 2941 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2942 name_str = "<no-name - thread is attaching>"; 2943 } 2944 else { 2945 name_str = Thread::name(); 2946 } 2947 } 2948 else { 2949 name_str = Thread::name(); 2950 } 2951 assert(name_str != NULL, "unexpected NULL thread name"); 2952 return name_str; 2953} 2954 2955 2956const char* JavaThread::get_threadgroup_name() const { 2957 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2958 oop thread_obj = threadObj(); 2959 if (thread_obj != NULL) { 2960 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2961 if (thread_group != NULL) { 2962 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2963 // ThreadGroup.name can be null 2964 if (name != NULL) { 2965 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2966 return str; 2967 } 2968 } 2969 } 2970 return NULL; 2971} 2972 2973const char* JavaThread::get_parent_name() const { 2974 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2975 oop thread_obj = threadObj(); 2976 if (thread_obj != NULL) { 2977 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2978 if (thread_group != NULL) { 2979 oop parent = java_lang_ThreadGroup::parent(thread_group); 2980 if (parent != NULL) { 2981 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2982 // ThreadGroup.name can be null 2983 if (name != NULL) { 2984 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2985 return str; 2986 } 2987 } 2988 } 2989 } 2990 return NULL; 2991} 2992 2993ThreadPriority JavaThread::java_priority() const { 2994 oop thr_oop = threadObj(); 2995 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2996 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2997 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2998 return priority; 2999} 3000 3001void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 3002 3003 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3004 // Link Java Thread object <-> C++ Thread 3005 3006 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3007 // and put it into a new Handle. The Handle "thread_oop" can then 3008 // be used to pass the C++ thread object to other methods. 3009 3010 // Set the Java level thread object (jthread) field of the 3011 // new thread (a JavaThread *) to C++ thread object using the 3012 // "thread_oop" handle. 3013 3014 // Set the thread field (a JavaThread *) of the 3015 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3016 3017 Handle thread_oop(Thread::current(), 3018 JNIHandles::resolve_non_null(jni_thread)); 3019 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3020 "must be initialized"); 3021 set_threadObj(thread_oop()); 3022 java_lang_Thread::set_thread(thread_oop(), this); 3023 3024 if (prio == NoPriority) { 3025 prio = java_lang_Thread::priority(thread_oop()); 3026 assert(prio != NoPriority, "A valid priority should be present"); 3027 } 3028 3029 // Push the Java priority down to the native thread; needs Threads_lock 3030 Thread::set_priority(this, prio); 3031 3032 // Add the new thread to the Threads list and set it in motion. 3033 // We must have threads lock in order to call Threads::add. 3034 // It is crucial that we do not block before the thread is 3035 // added to the Threads list for if a GC happens, then the java_thread oop 3036 // will not be visited by GC. 3037 Threads::add(this); 3038} 3039 3040oop JavaThread::current_park_blocker() { 3041 // Support for JSR-166 locks 3042 oop thread_oop = threadObj(); 3043 if (thread_oop != NULL && 3044 JDK_Version::current().supports_thread_park_blocker()) { 3045 return java_lang_Thread::park_blocker(thread_oop); 3046 } 3047 return NULL; 3048} 3049 3050 3051void JavaThread::print_stack_on(outputStream* st) { 3052 if (!has_last_Java_frame()) return; 3053 ResourceMark rm; 3054 HandleMark hm; 3055 3056 RegisterMap reg_map(this); 3057 vframe* start_vf = last_java_vframe(®_map); 3058 int count = 0; 3059 for (vframe* f = start_vf; f; f = f->sender() ) { 3060 if (f->is_java_frame()) { 3061 javaVFrame* jvf = javaVFrame::cast(f); 3062 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3063 3064 // Print out lock information 3065 if (JavaMonitorsInStackTrace) { 3066 jvf->print_lock_info_on(st, count); 3067 } 3068 } else { 3069 // Ignore non-Java frames 3070 } 3071 3072 // Bail-out case for too deep stacks 3073 count++; 3074 if (MaxJavaStackTraceDepth == count) return; 3075 } 3076} 3077 3078 3079// JVMTI PopFrame support 3080void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3081 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3082 if (in_bytes(size_in_bytes) != 0) { 3083 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3084 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3085 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3086 } 3087} 3088 3089void* JavaThread::popframe_preserved_args() { 3090 return _popframe_preserved_args; 3091} 3092 3093ByteSize JavaThread::popframe_preserved_args_size() { 3094 return in_ByteSize(_popframe_preserved_args_size); 3095} 3096 3097WordSize JavaThread::popframe_preserved_args_size_in_words() { 3098 int sz = in_bytes(popframe_preserved_args_size()); 3099 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3100 return in_WordSize(sz / wordSize); 3101} 3102 3103void JavaThread::popframe_free_preserved_args() { 3104 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3105 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3106 _popframe_preserved_args = NULL; 3107 _popframe_preserved_args_size = 0; 3108} 3109 3110#ifndef PRODUCT 3111 3112void JavaThread::trace_frames() { 3113 tty->print_cr("[Describe stack]"); 3114 int frame_no = 1; 3115 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3116 tty->print(" %d. ", frame_no++); 3117 fst.current()->print_value_on(tty,this); 3118 tty->cr(); 3119 } 3120} 3121 3122class PrintAndVerifyOopClosure: public OopClosure { 3123 protected: 3124 template <class T> inline void do_oop_work(T* p) { 3125 oop obj = oopDesc::load_decode_heap_oop(p); 3126 if (obj == NULL) return; 3127 tty->print(INTPTR_FORMAT ": ", p); 3128 if (obj->is_oop_or_null()) { 3129 if (obj->is_objArray()) { 3130 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3131 } else { 3132 obj->print(); 3133 } 3134 } else { 3135 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3136 } 3137 tty->cr(); 3138 } 3139 public: 3140 virtual void do_oop(oop* p) { do_oop_work(p); } 3141 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3142}; 3143 3144 3145static void oops_print(frame* f, const RegisterMap *map) { 3146 PrintAndVerifyOopClosure print; 3147 f->print_value(); 3148 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3149} 3150 3151// Print our all the locations that contain oops and whether they are 3152// valid or not. This useful when trying to find the oldest frame 3153// where an oop has gone bad since the frame walk is from youngest to 3154// oldest. 3155void JavaThread::trace_oops() { 3156 tty->print_cr("[Trace oops]"); 3157 frames_do(oops_print); 3158} 3159 3160 3161#ifdef ASSERT 3162// Print or validate the layout of stack frames 3163void JavaThread::print_frame_layout(int depth, bool validate_only) { 3164 ResourceMark rm; 3165 PRESERVE_EXCEPTION_MARK; 3166 FrameValues values; 3167 int frame_no = 0; 3168 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3169 fst.current()->describe(values, ++frame_no); 3170 if (depth == frame_no) break; 3171 } 3172 if (validate_only) { 3173 values.validate(); 3174 } else { 3175 tty->print_cr("[Describe stack layout]"); 3176 values.print(this); 3177 } 3178} 3179#endif 3180 3181void JavaThread::trace_stack_from(vframe* start_vf) { 3182 ResourceMark rm; 3183 int vframe_no = 1; 3184 for (vframe* f = start_vf; f; f = f->sender() ) { 3185 if (f->is_java_frame()) { 3186 javaVFrame::cast(f)->print_activation(vframe_no++); 3187 } else { 3188 f->print(); 3189 } 3190 if (vframe_no > StackPrintLimit) { 3191 tty->print_cr("...<more frames>..."); 3192 return; 3193 } 3194 } 3195} 3196 3197 3198void JavaThread::trace_stack() { 3199 if (!has_last_Java_frame()) return; 3200 ResourceMark rm; 3201 HandleMark hm; 3202 RegisterMap reg_map(this); 3203 trace_stack_from(last_java_vframe(®_map)); 3204} 3205 3206 3207#endif // PRODUCT 3208 3209 3210javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3211 assert(reg_map != NULL, "a map must be given"); 3212 frame f = last_frame(); 3213 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3214 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3215 } 3216 return NULL; 3217} 3218 3219 3220Klass* JavaThread::security_get_caller_class(int depth) { 3221 vframeStream vfst(this); 3222 vfst.security_get_caller_frame(depth); 3223 if (!vfst.at_end()) { 3224 return vfst.method()->method_holder(); 3225 } 3226 return NULL; 3227} 3228 3229static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3230 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3231 CompileBroker::compiler_thread_loop(); 3232} 3233 3234// Create a CompilerThread 3235CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3236: JavaThread(&compiler_thread_entry) { 3237 _env = NULL; 3238 _log = NULL; 3239 _task = NULL; 3240 _queue = queue; 3241 _counters = counters; 3242 _buffer_blob = NULL; 3243 _scanned_nmethod = NULL; 3244 _compiler = NULL; 3245 3246#ifndef PRODUCT 3247 _ideal_graph_printer = NULL; 3248#endif 3249} 3250 3251void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 3252 JavaThread::oops_do(f, cld_f, cf); 3253 if (_scanned_nmethod != NULL && cf != NULL) { 3254 // Safepoints can occur when the sweeper is scanning an nmethod so 3255 // process it here to make sure it isn't unloaded in the middle of 3256 // a scan. 3257 cf->do_code_blob(_scanned_nmethod); 3258 } 3259} 3260 3261 3262// ======= Threads ======== 3263 3264// The Threads class links together all active threads, and provides 3265// operations over all threads. It is protected by its own Mutex 3266// lock, which is also used in other contexts to protect thread 3267// operations from having the thread being operated on from exiting 3268// and going away unexpectedly (e.g., safepoint synchronization) 3269 3270JavaThread* Threads::_thread_list = NULL; 3271int Threads::_number_of_threads = 0; 3272int Threads::_number_of_non_daemon_threads = 0; 3273int Threads::_return_code = 0; 3274size_t JavaThread::_stack_size_at_create = 0; 3275#ifdef ASSERT 3276bool Threads::_vm_complete = false; 3277#endif 3278 3279// All JavaThreads 3280#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3281 3282// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3283void Threads::threads_do(ThreadClosure* tc) { 3284 assert_locked_or_safepoint(Threads_lock); 3285 // ALL_JAVA_THREADS iterates through all JavaThreads 3286 ALL_JAVA_THREADS(p) { 3287 tc->do_thread(p); 3288 } 3289 // Someday we could have a table or list of all non-JavaThreads. 3290 // For now, just manually iterate through them. 3291 tc->do_thread(VMThread::vm_thread()); 3292 Universe::heap()->gc_threads_do(tc); 3293 WatcherThread *wt = WatcherThread::watcher_thread(); 3294 // Strictly speaking, the following NULL check isn't sufficient to make sure 3295 // the data for WatcherThread is still valid upon being examined. However, 3296 // considering that WatchThread terminates when the VM is on the way to 3297 // exit at safepoint, the chance of the above is extremely small. The right 3298 // way to prevent termination of WatcherThread would be to acquire 3299 // Terminator_lock, but we can't do that without violating the lock rank 3300 // checking in some cases. 3301 if (wt != NULL) 3302 tc->do_thread(wt); 3303 3304 // If CompilerThreads ever become non-JavaThreads, add them here 3305} 3306 3307 3308void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3309 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3310 3311 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3312 create_vm_init_libraries(); 3313 } 3314 3315 initialize_class(vmSymbols::java_lang_String(), CHECK); 3316 3317 // Initialize java_lang.System (needed before creating the thread) 3318 initialize_class(vmSymbols::java_lang_System(), CHECK); 3319 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3320 Handle thread_group = create_initial_thread_group(CHECK); 3321 Universe::set_main_thread_group(thread_group()); 3322 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3323 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3324 main_thread->set_threadObj(thread_object); 3325 // Set thread status to running since main thread has 3326 // been started and running. 3327 java_lang_Thread::set_thread_status(thread_object, 3328 java_lang_Thread::RUNNABLE); 3329 3330 // The VM creates & returns objects of this class. Make sure it's initialized. 3331 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3332 3333 // The VM preresolves methods to these classes. Make sure that they get initialized 3334 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3335 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3336 call_initializeSystemClass(CHECK); 3337 3338 // get the Java runtime name after java.lang.System is initialized 3339 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3340 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3341 3342 // an instance of OutOfMemory exception has been allocated earlier 3343 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3344 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3345 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3346 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3347 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3348 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3349 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3350 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3351} 3352 3353void Threads::initialize_jsr292_core_classes(TRAPS) { 3354 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3355 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3356 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3357} 3358 3359jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3360 3361 extern void JDK_Version_init(); 3362 3363 // Check version 3364 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3365 3366 // Initialize the output stream module 3367 ostream_init(); 3368 3369 // Process java launcher properties. 3370 Arguments::process_sun_java_launcher_properties(args); 3371 3372 // Initialize the os module before using TLS 3373 os::init(); 3374 3375 // Initialize system properties. 3376 Arguments::init_system_properties(); 3377 3378 // So that JDK version can be used as a discriminator when parsing arguments 3379 JDK_Version_init(); 3380 3381 // Update/Initialize System properties after JDK version number is known 3382 Arguments::init_version_specific_system_properties(); 3383 3384 // Parse arguments 3385 jint parse_result = Arguments::parse(args); 3386 if (parse_result != JNI_OK) return parse_result; 3387 3388 os::init_before_ergo(); 3389 3390 jint ergo_result = Arguments::apply_ergo(); 3391 if (ergo_result != JNI_OK) return ergo_result; 3392 3393 if (PauseAtStartup) { 3394 os::pause(); 3395 } 3396 3397#ifndef USDT2 3398 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3399#else /* USDT2 */ 3400 HOTSPOT_VM_INIT_BEGIN(); 3401#endif /* USDT2 */ 3402 3403 // Record VM creation timing statistics 3404 TraceVmCreationTime create_vm_timer; 3405 create_vm_timer.start(); 3406 3407 // Timing (must come after argument parsing) 3408 TraceTime timer("Create VM", TraceStartupTime); 3409 3410 // Initialize the os module after parsing the args 3411 jint os_init_2_result = os::init_2(); 3412 if (os_init_2_result != JNI_OK) return os_init_2_result; 3413 3414 jint adjust_after_os_result = Arguments::adjust_after_os(); 3415 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3416 3417 // initialize TLS 3418 ThreadLocalStorage::init(); 3419 3420 // Bootstrap native memory tracking, so it can start recording memory 3421 // activities before worker thread is started. This is the first phase 3422 // of bootstrapping, VM is currently running in single-thread mode. 3423 MemTracker::bootstrap_single_thread(); 3424 3425 // Initialize output stream logging 3426 ostream_init_log(); 3427 3428 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3429 // Must be before create_vm_init_agents() 3430 if (Arguments::init_libraries_at_startup()) { 3431 convert_vm_init_libraries_to_agents(); 3432 } 3433 3434 // Launch -agentlib/-agentpath and converted -Xrun agents 3435 if (Arguments::init_agents_at_startup()) { 3436 create_vm_init_agents(); 3437 } 3438 3439 // Initialize Threads state 3440 _thread_list = NULL; 3441 _number_of_threads = 0; 3442 _number_of_non_daemon_threads = 0; 3443 3444 // Initialize global data structures and create system classes in heap 3445 vm_init_globals(); 3446 3447 // Attach the main thread to this os thread 3448 JavaThread* main_thread = new JavaThread(); 3449 main_thread->set_thread_state(_thread_in_vm); 3450 // must do this before set_active_handles and initialize_thread_local_storage 3451 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3452 // change the stack size recorded here to one based on the java thread 3453 // stacksize. This adjusted size is what is used to figure the placement 3454 // of the guard pages. 3455 main_thread->record_stack_base_and_size(); 3456 main_thread->initialize_thread_local_storage(); 3457 3458 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3459 3460 if (!main_thread->set_as_starting_thread()) { 3461 vm_shutdown_during_initialization( 3462 "Failed necessary internal allocation. Out of swap space"); 3463 delete main_thread; 3464 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3465 return JNI_ENOMEM; 3466 } 3467 3468 // Enable guard page *after* os::create_main_thread(), otherwise it would 3469 // crash Linux VM, see notes in os_linux.cpp. 3470 main_thread->create_stack_guard_pages(); 3471 3472 // Initialize Java-Level synchronization subsystem 3473 ObjectMonitor::Initialize() ; 3474 3475 // Second phase of bootstrapping, VM is about entering multi-thread mode 3476 MemTracker::bootstrap_multi_thread(); 3477 3478 // Initialize global modules 3479 jint status = init_globals(); 3480 if (status != JNI_OK) { 3481 delete main_thread; 3482 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3483 return status; 3484 } 3485 3486 // Should be done after the heap is fully created 3487 main_thread->cache_global_variables(); 3488 3489 HandleMark hm; 3490 3491 { MutexLocker mu(Threads_lock); 3492 Threads::add(main_thread); 3493 } 3494 3495 // Any JVMTI raw monitors entered in onload will transition into 3496 // real raw monitor. VM is setup enough here for raw monitor enter. 3497 JvmtiExport::transition_pending_onload_raw_monitors(); 3498 3499 // Fully start NMT 3500 MemTracker::start(); 3501 3502 // Create the VMThread 3503 { TraceTime timer("Start VMThread", TraceStartupTime); 3504 VMThread::create(); 3505 Thread* vmthread = VMThread::vm_thread(); 3506 3507 if (!os::create_thread(vmthread, os::vm_thread)) 3508 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3509 3510 // Wait for the VM thread to become ready, and VMThread::run to initialize 3511 // Monitors can have spurious returns, must always check another state flag 3512 { 3513 MutexLocker ml(Notify_lock); 3514 os::start_thread(vmthread); 3515 while (vmthread->active_handles() == NULL) { 3516 Notify_lock->wait(); 3517 } 3518 } 3519 } 3520 3521 assert (Universe::is_fully_initialized(), "not initialized"); 3522 if (VerifyDuringStartup) { 3523 // Make sure we're starting with a clean slate. 3524 VM_Verify verify_op; 3525 VMThread::execute(&verify_op); 3526 } 3527 3528 Thread* THREAD = Thread::current(); 3529 3530 // At this point, the Universe is initialized, but we have not executed 3531 // any byte code. Now is a good time (the only time) to dump out the 3532 // internal state of the JVM for sharing. 3533 if (DumpSharedSpaces) { 3534 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3535 ShouldNotReachHere(); 3536 } 3537 3538 // Always call even when there are not JVMTI environments yet, since environments 3539 // may be attached late and JVMTI must track phases of VM execution 3540 JvmtiExport::enter_start_phase(); 3541 3542 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3543 JvmtiExport::post_vm_start(); 3544 3545 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3546 3547 // We need this for ClassDataSharing - the initial vm.info property is set 3548 // with the default value of CDS "sharing" which may be reset through 3549 // command line options. 3550 reset_vm_info_property(CHECK_JNI_ERR); 3551 3552 quicken_jni_functions(); 3553 3554 // Must be run after init_ft which initializes ft_enabled 3555 if (TRACE_INITIALIZE() != JNI_OK) { 3556 vm_exit_during_initialization("Failed to initialize tracing backend"); 3557 } 3558 3559 // Set flag that basic initialization has completed. Used by exceptions and various 3560 // debug stuff, that does not work until all basic classes have been initialized. 3561 set_init_completed(); 3562 3563#ifndef USDT2 3564 HS_DTRACE_PROBE(hotspot, vm__init__end); 3565#else /* USDT2 */ 3566 HOTSPOT_VM_INIT_END(); 3567#endif /* USDT2 */ 3568 3569 // record VM initialization completion time 3570#if INCLUDE_MANAGEMENT 3571 Management::record_vm_init_completed(); 3572#endif // INCLUDE_MANAGEMENT 3573 3574 // Compute system loader. Note that this has to occur after set_init_completed, since 3575 // valid exceptions may be thrown in the process. 3576 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3577 // set_init_completed has just been called, causing exceptions not to be shortcut 3578 // anymore. We call vm_exit_during_initialization directly instead. 3579 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR); 3580 3581#if INCLUDE_ALL_GCS 3582 // Support for ConcurrentMarkSweep. This should be cleaned up 3583 // and better encapsulated. The ugly nested if test would go away 3584 // once things are properly refactored. XXX YSR 3585 if (UseConcMarkSweepGC || UseG1GC) { 3586 if (UseConcMarkSweepGC) { 3587 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3588 } else { 3589 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3590 } 3591 } 3592#endif // INCLUDE_ALL_GCS 3593 3594 // Always call even when there are not JVMTI environments yet, since environments 3595 // may be attached late and JVMTI must track phases of VM execution 3596 JvmtiExport::enter_live_phase(); 3597 3598 // Signal Dispatcher needs to be started before VMInit event is posted 3599 os::signal_init(); 3600 3601 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3602 if (!DisableAttachMechanism) { 3603 AttachListener::vm_start(); 3604 if (StartAttachListener || AttachListener::init_at_startup()) { 3605 AttachListener::init(); 3606 } 3607 } 3608 3609 // Launch -Xrun agents 3610 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3611 // back-end can launch with -Xdebug -Xrunjdwp. 3612 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3613 create_vm_init_libraries(); 3614 } 3615 3616 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3617 JvmtiExport::post_vm_initialized(); 3618 3619 if (TRACE_START() != JNI_OK) { 3620 vm_exit_during_initialization("Failed to start tracing backend."); 3621 } 3622 3623 if (CleanChunkPoolAsync) { 3624 Chunk::start_chunk_pool_cleaner_task(); 3625 } 3626 3627 // initialize compiler(s) 3628#if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3629 CompileBroker::compilation_init(); 3630#endif 3631 3632 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3633 // It is done after compilers are initialized, because otherwise compilations of 3634 // signature polymorphic MH intrinsics can be missed 3635 // (see SystemDictionary::find_method_handle_intrinsic). 3636 if (EnableInvokeDynamic) { 3637 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3638 } 3639 3640#if INCLUDE_MANAGEMENT 3641 Management::initialize(THREAD); 3642 3643 if (HAS_PENDING_EXCEPTION) { 3644 // management agent fails to start possibly due to 3645 // configuration problem and is responsible for printing 3646 // stack trace if appropriate. Simply exit VM. 3647 vm_exit(1); 3648 } 3649#endif // INCLUDE_MANAGEMENT 3650 3651 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3652 if (MemProfiling) MemProfiler::engage(); 3653 StatSampler::engage(); 3654 if (CheckJNICalls) JniPeriodicChecker::engage(); 3655 3656 BiasedLocking::init(); 3657 3658 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3659 call_postVMInitHook(THREAD); 3660 // The Java side of PostVMInitHook.run must deal with all 3661 // exceptions and provide means of diagnosis. 3662 if (HAS_PENDING_EXCEPTION) { 3663 CLEAR_PENDING_EXCEPTION; 3664 } 3665 } 3666 3667 { 3668 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3669 // Make sure the watcher thread can be started by WatcherThread::start() 3670 // or by dynamic enrollment. 3671 WatcherThread::make_startable(); 3672 // Start up the WatcherThread if there are any periodic tasks 3673 // NOTE: All PeriodicTasks should be registered by now. If they 3674 // aren't, late joiners might appear to start slowly (we might 3675 // take a while to process their first tick). 3676 if (PeriodicTask::num_tasks() > 0) { 3677 WatcherThread::start(); 3678 } 3679 } 3680 3681 // Give os specific code one last chance to start 3682 os::init_3(); 3683 3684 create_vm_timer.end(); 3685#ifdef ASSERT 3686 _vm_complete = true; 3687#endif 3688 return JNI_OK; 3689} 3690 3691// type for the Agent_OnLoad and JVM_OnLoad entry points 3692extern "C" { 3693 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3694} 3695// Find a command line agent library and return its entry point for 3696// -agentlib: -agentpath: -Xrun 3697// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3698static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3699 OnLoadEntry_t on_load_entry = NULL; 3700 void *library = NULL; 3701 3702 if (!agent->valid()) { 3703 char buffer[JVM_MAXPATHLEN]; 3704 char ebuf[1024]; 3705 const char *name = agent->name(); 3706 const char *msg = "Could not find agent library "; 3707 3708 // First check to see if agent is statically linked into executable 3709 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3710 library = agent->os_lib(); 3711 } else if (agent->is_absolute_path()) { 3712 library = os::dll_load(name, ebuf, sizeof ebuf); 3713 if (library == NULL) { 3714 const char *sub_msg = " in absolute path, with error: "; 3715 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3716 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3717 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3718 // If we can't find the agent, exit. 3719 vm_exit_during_initialization(buf, NULL); 3720 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3721 } 3722 } else { 3723 // Try to load the agent from the standard dll directory 3724 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3725 name)) { 3726 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3727 } 3728 if (library == NULL) { // Try the local directory 3729 char ns[1] = {0}; 3730 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3731 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3732 } 3733 if (library == NULL) { 3734 const char *sub_msg = " on the library path, with error: "; 3735 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3736 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3737 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3738 // If we can't find the agent, exit. 3739 vm_exit_during_initialization(buf, NULL); 3740 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3741 } 3742 } 3743 } 3744 agent->set_os_lib(library); 3745 agent->set_valid(); 3746 } 3747 3748 // Find the OnLoad function. 3749 on_load_entry = 3750 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3751 false, 3752 on_load_symbols, 3753 num_symbol_entries)); 3754 return on_load_entry; 3755} 3756 3757// Find the JVM_OnLoad entry point 3758static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3759 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3760 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3761} 3762 3763// Find the Agent_OnLoad entry point 3764static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3765 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3766 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3767} 3768 3769// For backwards compatibility with -Xrun 3770// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3771// treated like -agentpath: 3772// Must be called before agent libraries are created 3773void Threads::convert_vm_init_libraries_to_agents() { 3774 AgentLibrary* agent; 3775 AgentLibrary* next; 3776 3777 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3778 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3779 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3780 3781 // If there is an JVM_OnLoad function it will get called later, 3782 // otherwise see if there is an Agent_OnLoad 3783 if (on_load_entry == NULL) { 3784 on_load_entry = lookup_agent_on_load(agent); 3785 if (on_load_entry != NULL) { 3786 // switch it to the agent list -- so that Agent_OnLoad will be called, 3787 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3788 Arguments::convert_library_to_agent(agent); 3789 } else { 3790 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3791 } 3792 } 3793 } 3794} 3795 3796// Create agents for -agentlib: -agentpath: and converted -Xrun 3797// Invokes Agent_OnLoad 3798// Called very early -- before JavaThreads exist 3799void Threads::create_vm_init_agents() { 3800 extern struct JavaVM_ main_vm; 3801 AgentLibrary* agent; 3802 3803 JvmtiExport::enter_onload_phase(); 3804 3805 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3806 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3807 3808 if (on_load_entry != NULL) { 3809 // Invoke the Agent_OnLoad function 3810 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3811 if (err != JNI_OK) { 3812 vm_exit_during_initialization("agent library failed to init", agent->name()); 3813 } 3814 } else { 3815 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3816 } 3817 } 3818 JvmtiExport::enter_primordial_phase(); 3819} 3820 3821extern "C" { 3822 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3823} 3824 3825void Threads::shutdown_vm_agents() { 3826 // Send any Agent_OnUnload notifications 3827 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3828 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3829 extern struct JavaVM_ main_vm; 3830 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3831 3832 // Find the Agent_OnUnload function. 3833 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3834 os::find_agent_function(agent, 3835 false, 3836 on_unload_symbols, 3837 num_symbol_entries)); 3838 3839 // Invoke the Agent_OnUnload function 3840 if (unload_entry != NULL) { 3841 JavaThread* thread = JavaThread::current(); 3842 ThreadToNativeFromVM ttn(thread); 3843 HandleMark hm(thread); 3844 (*unload_entry)(&main_vm); 3845 } 3846 } 3847} 3848 3849// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3850// Invokes JVM_OnLoad 3851void Threads::create_vm_init_libraries() { 3852 extern struct JavaVM_ main_vm; 3853 AgentLibrary* agent; 3854 3855 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3856 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3857 3858 if (on_load_entry != NULL) { 3859 // Invoke the JVM_OnLoad function 3860 JavaThread* thread = JavaThread::current(); 3861 ThreadToNativeFromVM ttn(thread); 3862 HandleMark hm(thread); 3863 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3864 if (err != JNI_OK) { 3865 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3866 } 3867 } else { 3868 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3869 } 3870 } 3871} 3872 3873// Last thread running calls java.lang.Shutdown.shutdown() 3874void JavaThread::invoke_shutdown_hooks() { 3875 HandleMark hm(this); 3876 3877 // We could get here with a pending exception, if so clear it now. 3878 if (this->has_pending_exception()) { 3879 this->clear_pending_exception(); 3880 } 3881 3882 EXCEPTION_MARK; 3883 Klass* k = 3884 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3885 THREAD); 3886 if (k != NULL) { 3887 // SystemDictionary::resolve_or_null will return null if there was 3888 // an exception. If we cannot load the Shutdown class, just don't 3889 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3890 // and finalizers (if runFinalizersOnExit is set) won't be run. 3891 // Note that if a shutdown hook was registered or runFinalizersOnExit 3892 // was called, the Shutdown class would have already been loaded 3893 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3894 instanceKlassHandle shutdown_klass (THREAD, k); 3895 JavaValue result(T_VOID); 3896 JavaCalls::call_static(&result, 3897 shutdown_klass, 3898 vmSymbols::shutdown_method_name(), 3899 vmSymbols::void_method_signature(), 3900 THREAD); 3901 } 3902 CLEAR_PENDING_EXCEPTION; 3903} 3904 3905// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3906// the program falls off the end of main(). Another VM exit path is through 3907// vm_exit() when the program calls System.exit() to return a value or when 3908// there is a serious error in VM. The two shutdown paths are not exactly 3909// the same, but they share Shutdown.shutdown() at Java level and before_exit() 3910// and VM_Exit op at VM level. 3911// 3912// Shutdown sequence: 3913// + Shutdown native memory tracking if it is on 3914// + Wait until we are the last non-daemon thread to execute 3915// <-- every thing is still working at this moment --> 3916// + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3917// shutdown hooks, run finalizers if finalization-on-exit 3918// + Call before_exit(), prepare for VM exit 3919// > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3920// currently the only user of this mechanism is File.deleteOnExit()) 3921// > stop flat profiler, StatSampler, watcher thread, CMS threads, 3922// post thread end and vm death events to JVMTI, 3923// stop signal thread 3924// + Call JavaThread::exit(), it will: 3925// > release JNI handle blocks, remove stack guard pages 3926// > remove this thread from Threads list 3927// <-- no more Java code from this thread after this point --> 3928// + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3929// the compiler threads at safepoint 3930// <-- do not use anything that could get blocked by Safepoint --> 3931// + Disable tracing at JNI/JVM barriers 3932// + Set _vm_exited flag for threads that are still running native code 3933// + Delete this thread 3934// + Call exit_globals() 3935// > deletes tty 3936// > deletes PerfMemory resources 3937// + Return to caller 3938 3939bool Threads::destroy_vm() { 3940 JavaThread* thread = JavaThread::current(); 3941 3942#ifdef ASSERT 3943 _vm_complete = false; 3944#endif 3945 // Wait until we are the last non-daemon thread to execute 3946 { MutexLocker nu(Threads_lock); 3947 while (Threads::number_of_non_daemon_threads() > 1 ) 3948 // This wait should make safepoint checks, wait without a timeout, 3949 // and wait as a suspend-equivalent condition. 3950 // 3951 // Note: If the FlatProfiler is running and this thread is waiting 3952 // for another non-daemon thread to finish, then the FlatProfiler 3953 // is waiting for the external suspend request on this thread to 3954 // complete. wait_for_ext_suspend_completion() will eventually 3955 // timeout, but that takes time. Making this wait a suspend- 3956 // equivalent condition solves that timeout problem. 3957 // 3958 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3959 Mutex::_as_suspend_equivalent_flag); 3960 } 3961 3962 // Hang forever on exit if we are reporting an error. 3963 if (ShowMessageBoxOnError && is_error_reported()) { 3964 os::infinite_sleep(); 3965 } 3966 os::wait_for_keypress_at_exit(); 3967 3968 if (JDK_Version::is_jdk12x_version()) { 3969 // We are the last thread running, so check if finalizers should be run. 3970 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3971 HandleMark rm(thread); 3972 Universe::run_finalizers_on_exit(); 3973 } else { 3974 // run Java level shutdown hooks 3975 thread->invoke_shutdown_hooks(); 3976 } 3977 3978 before_exit(thread); 3979 3980 thread->exit(true); 3981 3982 // Stop VM thread. 3983 { 3984 // 4945125 The vm thread comes to a safepoint during exit. 3985 // GC vm_operations can get caught at the safepoint, and the 3986 // heap is unparseable if they are caught. Grab the Heap_lock 3987 // to prevent this. The GC vm_operations will not be able to 3988 // queue until after the vm thread is dead. 3989 // After this point, we'll never emerge out of the safepoint before 3990 // the VM exits, so concurrent GC threads do not need to be explicitly 3991 // stopped; they remain inactive until the process exits. 3992 // Note: some concurrent G1 threads may be running during a safepoint, 3993 // but these will not be accessing the heap, just some G1-specific side 3994 // data structures that are not accessed by any other threads but them 3995 // after this point in a terminal safepoint. 3996 3997 MutexLocker ml(Heap_lock); 3998 3999 VMThread::wait_for_vm_thread_exit(); 4000 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4001 VMThread::destroy(); 4002 } 4003 4004 // clean up ideal graph printers 4005#if defined(COMPILER2) && !defined(PRODUCT) 4006 IdealGraphPrinter::clean_up(); 4007#endif 4008 4009 // Now, all Java threads are gone except daemon threads. Daemon threads 4010 // running Java code or in VM are stopped by the Safepoint. However, 4011 // daemon threads executing native code are still running. But they 4012 // will be stopped at native=>Java/VM barriers. Note that we can't 4013 // simply kill or suspend them, as it is inherently deadlock-prone. 4014 4015#ifndef PRODUCT 4016 // disable function tracing at JNI/JVM barriers 4017 TraceJNICalls = false; 4018 TraceJVMCalls = false; 4019 TraceRuntimeCalls = false; 4020#endif 4021 4022 VM_Exit::set_vm_exited(); 4023 4024 notify_vm_shutdown(); 4025 4026 delete thread; 4027 4028 // exit_globals() will delete tty 4029 exit_globals(); 4030 4031 return true; 4032} 4033 4034 4035jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4036 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4037 return is_supported_jni_version(version); 4038} 4039 4040 4041jboolean Threads::is_supported_jni_version(jint version) { 4042 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4043 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4044 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4045 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4046 return JNI_FALSE; 4047} 4048 4049 4050void Threads::add(JavaThread* p, bool force_daemon) { 4051 // The threads lock must be owned at this point 4052 assert_locked_or_safepoint(Threads_lock); 4053 4054 // See the comment for this method in thread.hpp for its purpose and 4055 // why it is called here. 4056 p->initialize_queues(); 4057 p->set_next(_thread_list); 4058 _thread_list = p; 4059 _number_of_threads++; 4060 oop threadObj = p->threadObj(); 4061 bool daemon = true; 4062 // Bootstrapping problem: threadObj can be null for initial 4063 // JavaThread (or for threads attached via JNI) 4064 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4065 _number_of_non_daemon_threads++; 4066 daemon = false; 4067 } 4068 4069 p->set_safepoint_visible(true); 4070 4071 ThreadService::add_thread(p, daemon); 4072 4073 // Possible GC point. 4074 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4075} 4076 4077void Threads::remove(JavaThread* p) { 4078 // Extra scope needed for Thread_lock, so we can check 4079 // that we do not remove thread without safepoint code notice 4080 { MutexLocker ml(Threads_lock); 4081 4082 assert(includes(p), "p must be present"); 4083 4084 JavaThread* current = _thread_list; 4085 JavaThread* prev = NULL; 4086 4087 while (current != p) { 4088 prev = current; 4089 current = current->next(); 4090 } 4091 4092 if (prev) { 4093 prev->set_next(current->next()); 4094 } else { 4095 _thread_list = p->next(); 4096 } 4097 _number_of_threads--; 4098 oop threadObj = p->threadObj(); 4099 bool daemon = true; 4100 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4101 _number_of_non_daemon_threads--; 4102 daemon = false; 4103 4104 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4105 // on destroy_vm will wake up. 4106 if (number_of_non_daemon_threads() == 1) 4107 Threads_lock->notify_all(); 4108 } 4109 ThreadService::remove_thread(p, daemon); 4110 4111 // Make sure that safepoint code disregard this thread. This is needed since 4112 // the thread might mess around with locks after this point. This can cause it 4113 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4114 // of this thread since it is removed from the queue. 4115 p->set_terminated_value(); 4116 4117 // Now, this thread is not visible to safepoint 4118 p->set_safepoint_visible(false); 4119 // once the thread becomes safepoint invisible, we can not use its per-thread 4120 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4121 // to release its per-thread recorder here. 4122 MemTracker::thread_exiting(p); 4123 } // unlock Threads_lock 4124 4125 // Since Events::log uses a lock, we grab it outside the Threads_lock 4126 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4127} 4128 4129// Threads_lock must be held when this is called (or must be called during a safepoint) 4130bool Threads::includes(JavaThread* p) { 4131 assert(Threads_lock->is_locked(), "sanity check"); 4132 ALL_JAVA_THREADS(q) { 4133 if (q == p ) { 4134 return true; 4135 } 4136 } 4137 return false; 4138} 4139 4140// Operations on the Threads list for GC. These are not explicitly locked, 4141// but the garbage collector must provide a safe context for them to run. 4142// In particular, these things should never be called when the Threads_lock 4143// is held by some other thread. (Note: the Safepoint abstraction also 4144// uses the Threads_lock to guarantee this property. It also makes sure that 4145// all threads gets blocked when exiting or starting). 4146 4147void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4148 ALL_JAVA_THREADS(p) { 4149 p->oops_do(f, cld_f, cf); 4150 } 4151 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4152} 4153 4154void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4155 // Introduce a mechanism allowing parallel threads to claim threads as 4156 // root groups. Overhead should be small enough to use all the time, 4157 // even in sequential code. 4158 SharedHeap* sh = SharedHeap::heap(); 4159 // Cannot yet substitute active_workers for n_par_threads 4160 // because of G1CollectedHeap::verify() use of 4161 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4162 // turn off parallelism in process_strong_roots while active_workers 4163 // is being used for parallelism elsewhere. 4164 bool is_par = sh->n_par_threads() > 0; 4165 assert(!is_par || 4166 (SharedHeap::heap()->n_par_threads() == 4167 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4168 int cp = SharedHeap::heap()->strong_roots_parity(); 4169 ALL_JAVA_THREADS(p) { 4170 if (p->claim_oops_do(is_par, cp)) { 4171 p->oops_do(f, cld_f, cf); 4172 } 4173 } 4174 VMThread* vmt = VMThread::vm_thread(); 4175 if (vmt->claim_oops_do(is_par, cp)) { 4176 vmt->oops_do(f, cld_f, cf); 4177 } 4178} 4179 4180#if INCLUDE_ALL_GCS 4181// Used by ParallelScavenge 4182void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4183 ALL_JAVA_THREADS(p) { 4184 q->enqueue(new ThreadRootsTask(p)); 4185 } 4186 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4187} 4188 4189// Used by Parallel Old 4190void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4191 ALL_JAVA_THREADS(p) { 4192 q->enqueue(new ThreadRootsMarkingTask(p)); 4193 } 4194 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4195} 4196#endif // INCLUDE_ALL_GCS 4197 4198void Threads::nmethods_do(CodeBlobClosure* cf) { 4199 ALL_JAVA_THREADS(p) { 4200 p->nmethods_do(cf); 4201 } 4202 VMThread::vm_thread()->nmethods_do(cf); 4203} 4204 4205void Threads::metadata_do(void f(Metadata*)) { 4206 ALL_JAVA_THREADS(p) { 4207 p->metadata_do(f); 4208 } 4209} 4210 4211void Threads::gc_epilogue() { 4212 ALL_JAVA_THREADS(p) { 4213 p->gc_epilogue(); 4214 } 4215} 4216 4217void Threads::gc_prologue() { 4218 ALL_JAVA_THREADS(p) { 4219 p->gc_prologue(); 4220 } 4221} 4222 4223void Threads::deoptimized_wrt_marked_nmethods() { 4224 ALL_JAVA_THREADS(p) { 4225 p->deoptimized_wrt_marked_nmethods(); 4226 } 4227} 4228 4229 4230// Get count Java threads that are waiting to enter the specified monitor. 4231GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4232 address monitor, bool doLock) { 4233 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4234 "must grab Threads_lock or be at safepoint"); 4235 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4236 4237 int i = 0; 4238 { 4239 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4240 ALL_JAVA_THREADS(p) { 4241 if (p->is_Compiler_thread()) continue; 4242 4243 address pending = (address)p->current_pending_monitor(); 4244 if (pending == monitor) { // found a match 4245 if (i < count) result->append(p); // save the first count matches 4246 i++; 4247 } 4248 } 4249 } 4250 return result; 4251} 4252 4253 4254JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4255 assert(doLock || 4256 Threads_lock->owned_by_self() || 4257 SafepointSynchronize::is_at_safepoint(), 4258 "must grab Threads_lock or be at safepoint"); 4259 4260 // NULL owner means not locked so we can skip the search 4261 if (owner == NULL) return NULL; 4262 4263 { 4264 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4265 ALL_JAVA_THREADS(p) { 4266 // first, see if owner is the address of a Java thread 4267 if (owner == (address)p) return p; 4268 } 4269 } 4270 // Cannot assert on lack of success here since this function may be 4271 // used by code that is trying to report useful problem information 4272 // like deadlock detection. 4273 if (UseHeavyMonitors) return NULL; 4274 4275 // 4276 // If we didn't find a matching Java thread and we didn't force use of 4277 // heavyweight monitors, then the owner is the stack address of the 4278 // Lock Word in the owning Java thread's stack. 4279 // 4280 JavaThread* the_owner = NULL; 4281 { 4282 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4283 ALL_JAVA_THREADS(q) { 4284 if (q->is_lock_owned(owner)) { 4285 the_owner = q; 4286 break; 4287 } 4288 } 4289 } 4290 // cannot assert on lack of success here; see above comment 4291 return the_owner; 4292} 4293 4294// Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4295void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4296 char buf[32]; 4297 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4298 4299 st->print_cr("Full thread dump %s (%s %s):", 4300 Abstract_VM_Version::vm_name(), 4301 Abstract_VM_Version::vm_release(), 4302 Abstract_VM_Version::vm_info_string() 4303 ); 4304 st->cr(); 4305 4306#if INCLUDE_ALL_GCS 4307 // Dump concurrent locks 4308 ConcurrentLocksDump concurrent_locks; 4309 if (print_concurrent_locks) { 4310 concurrent_locks.dump_at_safepoint(); 4311 } 4312#endif // INCLUDE_ALL_GCS 4313 4314 ALL_JAVA_THREADS(p) { 4315 ResourceMark rm; 4316 p->print_on(st); 4317 if (print_stacks) { 4318 if (internal_format) { 4319 p->trace_stack(); 4320 } else { 4321 p->print_stack_on(st); 4322 } 4323 } 4324 st->cr(); 4325#if INCLUDE_ALL_GCS 4326 if (print_concurrent_locks) { 4327 concurrent_locks.print_locks_on(p, st); 4328 } 4329#endif // INCLUDE_ALL_GCS 4330 } 4331 4332 VMThread::vm_thread()->print_on(st); 4333 st->cr(); 4334 Universe::heap()->print_gc_threads_on(st); 4335 WatcherThread* wt = WatcherThread::watcher_thread(); 4336 if (wt != NULL) { 4337 wt->print_on(st); 4338 st->cr(); 4339 } 4340 CompileBroker::print_compiler_threads_on(st); 4341 st->flush(); 4342} 4343 4344// Threads::print_on_error() is called by fatal error handler. It's possible 4345// that VM is not at safepoint and/or current thread is inside signal handler. 4346// Don't print stack trace, as the stack may not be walkable. Don't allocate 4347// memory (even in resource area), it might deadlock the error handler. 4348void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4349 bool found_current = false; 4350 st->print_cr("Java Threads: ( => current thread )"); 4351 ALL_JAVA_THREADS(thread) { 4352 bool is_current = (current == thread); 4353 found_current = found_current || is_current; 4354 4355 st->print("%s", is_current ? "=>" : " "); 4356 4357 st->print(PTR_FORMAT, thread); 4358 st->print(" "); 4359 thread->print_on_error(st, buf, buflen); 4360 st->cr(); 4361 } 4362 st->cr(); 4363 4364 st->print_cr("Other Threads:"); 4365 if (VMThread::vm_thread()) { 4366 bool is_current = (current == VMThread::vm_thread()); 4367 found_current = found_current || is_current; 4368 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4369 4370 st->print(PTR_FORMAT, VMThread::vm_thread()); 4371 st->print(" "); 4372 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4373 st->cr(); 4374 } 4375 WatcherThread* wt = WatcherThread::watcher_thread(); 4376 if (wt != NULL) { 4377 bool is_current = (current == wt); 4378 found_current = found_current || is_current; 4379 st->print("%s", is_current ? "=>" : " "); 4380 4381 st->print(PTR_FORMAT, wt); 4382 st->print(" "); 4383 wt->print_on_error(st, buf, buflen); 4384 st->cr(); 4385 } 4386 if (!found_current) { 4387 st->cr(); 4388 st->print("=>" PTR_FORMAT " (exited) ", current); 4389 current->print_on_error(st, buf, buflen); 4390 st->cr(); 4391 } 4392} 4393 4394// Internal SpinLock and Mutex 4395// Based on ParkEvent 4396 4397// Ad-hoc mutual exclusion primitives: SpinLock and Mux 4398// 4399// We employ SpinLocks _only for low-contention, fixed-length 4400// short-duration critical sections where we're concerned 4401// about native mutex_t or HotSpot Mutex:: latency. 4402// The mux construct provides a spin-then-block mutual exclusion 4403// mechanism. 4404// 4405// Testing has shown that contention on the ListLock guarding gFreeList 4406// is common. If we implement ListLock as a simple SpinLock it's common 4407// for the JVM to devolve to yielding with little progress. This is true 4408// despite the fact that the critical sections protected by ListLock are 4409// extremely short. 4410// 4411// TODO-FIXME: ListLock should be of type SpinLock. 4412// We should make this a 1st-class type, integrated into the lock 4413// hierarchy as leaf-locks. Critically, the SpinLock structure 4414// should have sufficient padding to avoid false-sharing and excessive 4415// cache-coherency traffic. 4416 4417 4418typedef volatile int SpinLockT ; 4419 4420void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4421 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4422 return ; // normal fast-path return 4423 } 4424 4425 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4426 TEVENT (SpinAcquire - ctx) ; 4427 int ctr = 0 ; 4428 int Yields = 0 ; 4429 for (;;) { 4430 while (*adr != 0) { 4431 ++ctr ; 4432 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4433 if (Yields > 5) { 4434 os::naked_short_sleep(1); 4435 } else { 4436 os::NakedYield() ; 4437 ++Yields ; 4438 } 4439 } else { 4440 SpinPause() ; 4441 } 4442 } 4443 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4444 } 4445} 4446 4447void Thread::SpinRelease (volatile int * adr) { 4448 assert (*adr != 0, "invariant") ; 4449 OrderAccess::fence() ; // guarantee at least release consistency. 4450 // Roach-motel semantics. 4451 // It's safe if subsequent LDs and STs float "up" into the critical section, 4452 // but prior LDs and STs within the critical section can't be allowed 4453 // to reorder or float past the ST that releases the lock. 4454 *adr = 0 ; 4455} 4456 4457// muxAcquire and muxRelease: 4458// 4459// * muxAcquire and muxRelease support a single-word lock-word construct. 4460// The LSB of the word is set IFF the lock is held. 4461// The remainder of the word points to the head of a singly-linked list 4462// of threads blocked on the lock. 4463// 4464// * The current implementation of muxAcquire-muxRelease uses its own 4465// dedicated Thread._MuxEvent instance. If we're interested in 4466// minimizing the peak number of extant ParkEvent instances then 4467// we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4468// as certain invariants were satisfied. Specifically, care would need 4469// to be taken with regards to consuming unpark() "permits". 4470// A safe rule of thumb is that a thread would never call muxAcquire() 4471// if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4472// park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4473// consume an unpark() permit intended for monitorenter, for instance. 4474// One way around this would be to widen the restricted-range semaphore 4475// implemented in park(). Another alternative would be to provide 4476// multiple instances of the PlatformEvent() for each thread. One 4477// instance would be dedicated to muxAcquire-muxRelease, for instance. 4478// 4479// * Usage: 4480// -- Only as leaf locks 4481// -- for short-term locking only as muxAcquire does not perform 4482// thread state transitions. 4483// 4484// Alternatives: 4485// * We could implement muxAcquire and muxRelease with MCS or CLH locks 4486// but with parking or spin-then-park instead of pure spinning. 4487// * Use Taura-Oyama-Yonenzawa locks. 4488// * It's possible to construct a 1-0 lock if we encode the lockword as 4489// (List,LockByte). Acquire will CAS the full lockword while Release 4490// will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4491// acquiring threads use timers (ParkTimed) to detect and recover from 4492// the stranding window. Thread/Node structures must be aligned on 256-byte 4493// boundaries by using placement-new. 4494// * Augment MCS with advisory back-link fields maintained with CAS(). 4495// Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4496// The validity of the backlinks must be ratified before we trust the value. 4497// If the backlinks are invalid the exiting thread must back-track through the 4498// the forward links, which are always trustworthy. 4499// * Add a successor indication. The LockWord is currently encoded as 4500// (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4501// to provide the usual futile-wakeup optimization. 4502// See RTStt for details. 4503// * Consider schedctl.sc_nopreempt to cover the critical section. 4504// 4505 4506 4507typedef volatile intptr_t MutexT ; // Mux Lock-word 4508enum MuxBits { LOCKBIT = 1 } ; 4509 4510void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4511 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4512 if (w == 0) return ; 4513 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4514 return ; 4515 } 4516 4517 TEVENT (muxAcquire - Contention) ; 4518 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4519 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4520 for (;;) { 4521 int its = (os::is_MP() ? 100 : 0) + 1 ; 4522 4523 // Optional spin phase: spin-then-park strategy 4524 while (--its >= 0) { 4525 w = *Lock ; 4526 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4527 return ; 4528 } 4529 } 4530 4531 Self->reset() ; 4532 Self->OnList = intptr_t(Lock) ; 4533 // The following fence() isn't _strictly necessary as the subsequent 4534 // CAS() both serializes execution and ratifies the fetched *Lock value. 4535 OrderAccess::fence(); 4536 for (;;) { 4537 w = *Lock ; 4538 if ((w & LOCKBIT) == 0) { 4539 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4540 Self->OnList = 0 ; // hygiene - allows stronger asserts 4541 return ; 4542 } 4543 continue ; // Interference -- *Lock changed -- Just retry 4544 } 4545 assert (w & LOCKBIT, "invariant") ; 4546 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4547 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4548 } 4549 4550 while (Self->OnList != 0) { 4551 Self->park() ; 4552 } 4553 } 4554} 4555 4556void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4557 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4558 if (w == 0) return ; 4559 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4560 return ; 4561 } 4562 4563 TEVENT (muxAcquire - Contention) ; 4564 ParkEvent * ReleaseAfter = NULL ; 4565 if (ev == NULL) { 4566 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4567 } 4568 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4569 for (;;) { 4570 guarantee (ev->OnList == 0, "invariant") ; 4571 int its = (os::is_MP() ? 100 : 0) + 1 ; 4572 4573 // Optional spin phase: spin-then-park strategy 4574 while (--its >= 0) { 4575 w = *Lock ; 4576 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4577 if (ReleaseAfter != NULL) { 4578 ParkEvent::Release (ReleaseAfter) ; 4579 } 4580 return ; 4581 } 4582 } 4583 4584 ev->reset() ; 4585 ev->OnList = intptr_t(Lock) ; 4586 // The following fence() isn't _strictly necessary as the subsequent 4587 // CAS() both serializes execution and ratifies the fetched *Lock value. 4588 OrderAccess::fence(); 4589 for (;;) { 4590 w = *Lock ; 4591 if ((w & LOCKBIT) == 0) { 4592 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4593 ev->OnList = 0 ; 4594 // We call ::Release while holding the outer lock, thus 4595 // artificially lengthening the critical section. 4596 // Consider deferring the ::Release() until the subsequent unlock(), 4597 // after we've dropped the outer lock. 4598 if (ReleaseAfter != NULL) { 4599 ParkEvent::Release (ReleaseAfter) ; 4600 } 4601 return ; 4602 } 4603 continue ; // Interference -- *Lock changed -- Just retry 4604 } 4605 assert (w & LOCKBIT, "invariant") ; 4606 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4607 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4608 } 4609 4610 while (ev->OnList != 0) { 4611 ev->park() ; 4612 } 4613 } 4614} 4615 4616// Release() must extract a successor from the list and then wake that thread. 4617// It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4618// similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4619// Release() would : 4620// (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4621// (B) Extract a successor from the private list "in-hand" 4622// (C) attempt to CAS() the residual back into *Lock over null. 4623// If there were any newly arrived threads and the CAS() would fail. 4624// In that case Release() would detach the RATs, re-merge the list in-hand 4625// with the RATs and repeat as needed. Alternately, Release() might 4626// detach and extract a successor, but then pass the residual list to the wakee. 4627// The wakee would be responsible for reattaching and remerging before it 4628// competed for the lock. 4629// 4630// Both "pop" and DMR are immune from ABA corruption -- there can be 4631// multiple concurrent pushers, but only one popper or detacher. 4632// This implementation pops from the head of the list. This is unfair, 4633// but tends to provide excellent throughput as hot threads remain hot. 4634// (We wake recently run threads first). 4635 4636void Thread::muxRelease (volatile intptr_t * Lock) { 4637 for (;;) { 4638 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4639 assert (w & LOCKBIT, "invariant") ; 4640 if (w == LOCKBIT) return ; 4641 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4642 assert (List != NULL, "invariant") ; 4643 assert (List->OnList == intptr_t(Lock), "invariant") ; 4644 ParkEvent * nxt = List->ListNext ; 4645 4646 // The following CAS() releases the lock and pops the head element. 4647 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4648 continue ; 4649 } 4650 List->OnList = 0 ; 4651 OrderAccess::fence() ; 4652 List->unpark () ; 4653 return ; 4654 } 4655} 4656 4657 4658void Threads::verify() { 4659 ALL_JAVA_THREADS(p) { 4660 p->verify(); 4661 } 4662 VMThread* thread = VMThread::vm_thread(); 4663 if (thread != NULL) thread->verify(); 4664} 4665