thread.cpp revision 6403:97356e139532
1274876Sbapt/* 2274876Sbapt * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. 3274876Sbapt * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4274876Sbapt * 5274876Sbapt * This code is free software; you can redistribute it and/or modify it 6294113Sbapt * under the terms of the GNU General Public License version 2 only, as 7274876Sbapt * 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/orderAccess.inline.hpp" 62#include "runtime/osThread.hpp" 63#include "runtime/safepoint.hpp" 64#include "runtime/sharedRuntime.hpp" 65#include "runtime/statSampler.hpp" 66#include "runtime/stubRoutines.hpp" 67#include "runtime/task.hpp" 68#include "runtime/thread.inline.hpp" 69#include "runtime/threadCritical.hpp" 70#include "runtime/threadLocalStorage.hpp" 71#include "runtime/vframe.hpp" 72#include "runtime/vframeArray.hpp" 73#include "runtime/vframe_hp.hpp" 74#include "runtime/vmThread.hpp" 75#include "runtime/vm_operations.hpp" 76#include "services/attachListener.hpp" 77#include "services/management.hpp" 78#include "services/memTracker.hpp" 79#include "services/threadService.hpp" 80#include "trace/tracing.hpp" 81#include "trace/traceMacros.hpp" 82#include "utilities/defaultStream.hpp" 83#include "utilities/dtrace.hpp" 84#include "utilities/events.hpp" 85#include "utilities/preserveException.hpp" 86#include "utilities/macros.hpp" 87#ifdef TARGET_OS_FAMILY_linux 88# include "os_linux.inline.hpp" 89#endif 90#ifdef TARGET_OS_FAMILY_solaris 91# include "os_solaris.inline.hpp" 92#endif 93#ifdef TARGET_OS_FAMILY_windows 94# include "os_windows.inline.hpp" 95#endif 96#ifdef TARGET_OS_FAMILY_bsd 97# include "os_bsd.inline.hpp" 98#endif 99#if INCLUDE_ALL_GCS 100#include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 101#include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 102#include "gc_implementation/parallelScavenge/pcTasks.hpp" 103#endif // INCLUDE_ALL_GCS 104#ifdef COMPILER1 105#include "c1/c1_Compiler.hpp" 106#endif 107#ifdef COMPILER2 108#include "opto/c2compiler.hpp" 109#include "opto/idealGraphPrinter.hpp" 110#endif 111#if INCLUDE_RTM_OPT 112#include "runtime/rtmLocking.hpp" 113#endif 114 115#ifdef DTRACE_ENABLED 116 117// Only bother with this argument setup if dtrace is available 118 119#define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 120#define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 121 122#define DTRACE_THREAD_PROBE(probe, javathread) \ 123 { \ 124 ResourceMark rm(this); \ 125 int len = 0; \ 126 const char* name = (javathread)->get_thread_name(); \ 127 len = strlen(name); \ 128 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 129 (char *) name, len, \ 130 java_lang_Thread::thread_id((javathread)->threadObj()), \ 131 (uintptr_t) (javathread)->osthread()->thread_id(), \ 132 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 133 } 134 135#else // ndef DTRACE_ENABLED 136 137#define DTRACE_THREAD_PROBE(probe, javathread) 138 139#endif // ndef DTRACE_ENABLED 140 141 142// Class hierarchy 143// - Thread 144// - VMThread 145// - WatcherThread 146// - ConcurrentMarkSweepThread 147// - JavaThread 148// - CompilerThread 149 150// ======= Thread ======== 151// Support for forcing alignment of thread objects for biased locking 152void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 153 if (UseBiasedLocking) { 154 const int alignment = markOopDesc::biased_lock_alignment; 155 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 156 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 157 : AllocateHeap(aligned_size, flags, CURRENT_PC, 158 AllocFailStrategy::RETURN_NULL); 159 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 160 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 161 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 162 "JavaThread alignment code overflowed allocated storage"); 163 if (TraceBiasedLocking) { 164 if (aligned_addr != real_malloc_addr) 165 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 166 real_malloc_addr, aligned_addr); 167 } 168 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 169 return aligned_addr; 170 } else { 171 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 172 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 173 } 174} 175 176void Thread::operator delete(void* p) { 177 if (UseBiasedLocking) { 178 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 179 FreeHeap(real_malloc_addr, mtThread); 180 } else { 181 FreeHeap(p, mtThread); 182 } 183} 184 185 186// Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 187// JavaThread 188 189 190Thread::Thread() { 191 // stack and get_thread 192 set_stack_base(NULL); 193 set_stack_size(0); 194 set_self_raw_id(0); 195 set_lgrp_id(-1); 196 197 // allocated data structures 198 set_osthread(NULL); 199 set_resource_area(new (mtThread)ResourceArea()); 200 DEBUG_ONLY(_current_resource_mark = NULL;) 201 set_handle_area(new (mtThread) HandleArea(NULL)); 202 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 203 set_active_handles(NULL); 204 set_free_handle_block(NULL); 205 set_last_handle_mark(NULL); 206 207 // This initial value ==> never claimed. 208 _oops_do_parity = 0; 209 210 // the handle mark links itself to last_handle_mark 211 new HandleMark(this); 212 213 // plain initialization 214 debug_only(_owned_locks = NULL;) 215 debug_only(_allow_allocation_count = 0;) 216 NOT_PRODUCT(_allow_safepoint_count = 0;) 217 NOT_PRODUCT(_skip_gcalot = false;) 218 _jvmti_env_iteration_count = 0; 219 set_allocated_bytes(0); 220 _vm_operation_started_count = 0; 221 _vm_operation_completed_count = 0; 222 _current_pending_monitor = NULL; 223 _current_pending_monitor_is_from_java = true; 224 _current_waiting_monitor = NULL; 225 _num_nested_signal = 0; 226 omFreeList = NULL ; 227 omFreeCount = 0 ; 228 omFreeProvision = 32 ; 229 omInUseList = NULL ; 230 omInUseCount = 0 ; 231 232#ifdef ASSERT 233 _visited_for_critical_count = false; 234#endif 235 236 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 237 _suspend_flags = 0; 238 239 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 240 _hashStateX = os::random() ; 241 _hashStateY = 842502087 ; 242 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 243 _hashStateW = 273326509 ; 244 245 _OnTrap = 0 ; 246 _schedctl = NULL ; 247 _Stalled = 0 ; 248 _TypeTag = 0x2BAD ; 249 250 // Many of the following fields are effectively final - immutable 251 // Note that nascent threads can't use the Native Monitor-Mutex 252 // construct until the _MutexEvent is initialized ... 253 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 254 // we might instead use a stack of ParkEvents that we could provision on-demand. 255 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 256 // and ::Release() 257 _ParkEvent = ParkEvent::Allocate (this) ; 258 _SleepEvent = ParkEvent::Allocate (this) ; 259 _MutexEvent = ParkEvent::Allocate (this) ; 260 _MuxEvent = ParkEvent::Allocate (this) ; 261 262#ifdef CHECK_UNHANDLED_OOPS 263 if (CheckUnhandledOops) { 264 _unhandled_oops = new UnhandledOops(this); 265 } 266#endif // CHECK_UNHANDLED_OOPS 267#ifdef ASSERT 268 if (UseBiasedLocking) { 269 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 270 assert(this == _real_malloc_address || 271 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 272 "bug in forced alignment of thread objects"); 273 } 274#endif /* ASSERT */ 275} 276 277void Thread::initialize_thread_local_storage() { 278 // Note: Make sure this method only calls 279 // non-blocking operations. Otherwise, it might not work 280 // with the thread-startup/safepoint interaction. 281 282 // During Java thread startup, safepoint code should allow this 283 // method to complete because it may need to allocate memory to 284 // store information for the new thread. 285 286 // initialize structure dependent on thread local storage 287 ThreadLocalStorage::set_thread(this); 288} 289 290void Thread::record_stack_base_and_size() { 291 set_stack_base(os::current_stack_base()); 292 set_stack_size(os::current_stack_size()); 293 if (is_Java_thread()) { 294 ((JavaThread*) this)->set_stack_overflow_limit(); 295 } 296 // CR 7190089: on Solaris, primordial thread's stack is adjusted 297 // in initialize_thread(). Without the adjustment, stack size is 298 // incorrect if stack is set to unlimited (ulimit -s unlimited). 299 // So far, only Solaris has real implementation of initialize_thread(). 300 // 301 // set up any platform-specific state. 302 os::initialize_thread(this); 303 304#if INCLUDE_NMT 305 // record thread's native stack, stack grows downward 306 address stack_low_addr = stack_base() - stack_size(); 307 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 308 CURRENT_PC); 309#endif // INCLUDE_NMT 310} 311 312 313Thread::~Thread() { 314 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 315 ObjectSynchronizer::omFlush (this) ; 316 317 EVENT_THREAD_DESTRUCT(this); 318 319 // stack_base can be NULL if the thread is never started or exited before 320 // record_stack_base_and_size called. Although, we would like to ensure 321 // that all started threads do call record_stack_base_and_size(), there is 322 // not proper way to enforce that. 323#if INCLUDE_NMT 324 if (_stack_base != NULL) { 325 address low_stack_addr = stack_base() - stack_size(); 326 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); 327#ifdef ASSERT 328 set_stack_base(NULL); 329#endif 330 } 331#endif // INCLUDE_NMT 332 333 // deallocate data structures 334 delete resource_area(); 335 // since the handle marks are using the handle area, we have to deallocated the root 336 // handle mark before deallocating the thread's handle area, 337 assert(last_handle_mark() != NULL, "check we have an element"); 338 delete last_handle_mark(); 339 assert(last_handle_mark() == NULL, "check we have reached the end"); 340 341 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 342 // We NULL out the fields for good hygiene. 343 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 344 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 345 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 346 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 347 348 delete handle_area(); 349 delete metadata_handles(); 350 351 // osthread() can be NULL, if creation of thread failed. 352 if (osthread() != NULL) os::free_thread(osthread()); 353 354 delete _SR_lock; 355 356 // clear thread local storage if the Thread is deleting itself 357 if (this == Thread::current()) { 358 ThreadLocalStorage::set_thread(NULL); 359 } else { 360 // In the case where we're not the current thread, invalidate all the 361 // caches in case some code tries to get the current thread or the 362 // thread that was destroyed, and gets stale information. 363 ThreadLocalStorage::invalidate_all(); 364 } 365 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 366} 367 368// NOTE: dummy function for assertion purpose. 369void Thread::run() { 370 ShouldNotReachHere(); 371} 372 373#ifdef ASSERT 374// Private method to check for dangling thread pointer 375void check_for_dangling_thread_pointer(Thread *thread) { 376 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 377 "possibility of dangling Thread pointer"); 378} 379#endif 380 381 382#ifndef PRODUCT 383// Tracing method for basic thread operations 384void Thread::trace(const char* msg, const Thread* const thread) { 385 if (!TraceThreadEvents) return; 386 ResourceMark rm; 387 ThreadCritical tc; 388 const char *name = "non-Java thread"; 389 int prio = -1; 390 if (thread->is_Java_thread() 391 && !thread->is_Compiler_thread()) { 392 // The Threads_lock must be held to get information about 393 // this thread but may not be in some situations when 394 // tracing thread events. 395 bool release_Threads_lock = false; 396 if (!Threads_lock->owned_by_self()) { 397 Threads_lock->lock(); 398 release_Threads_lock = true; 399 } 400 JavaThread* jt = (JavaThread *)thread; 401 name = (char *)jt->get_thread_name(); 402 oop thread_oop = jt->threadObj(); 403 if (thread_oop != NULL) { 404 prio = java_lang_Thread::priority(thread_oop); 405 } 406 if (release_Threads_lock) { 407 Threads_lock->unlock(); 408 } 409 } 410 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 411} 412#endif 413 414 415ThreadPriority Thread::get_priority(const Thread* const thread) { 416 trace("get priority", thread); 417 ThreadPriority priority; 418 // Can return an error! 419 (void)os::get_priority(thread, priority); 420 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 421 return priority; 422} 423 424void Thread::set_priority(Thread* thread, ThreadPriority priority) { 425 trace("set priority", thread); 426 debug_only(check_for_dangling_thread_pointer(thread);) 427 // Can return an error! 428 (void)os::set_priority(thread, priority); 429} 430 431 432void Thread::start(Thread* thread) { 433 trace("start", thread); 434 // Start is different from resume in that its safety is guaranteed by context or 435 // being called from a Java method synchronized on the Thread object. 436 if (!DisableStartThread) { 437 if (thread->is_Java_thread()) { 438 // Initialize the thread state to RUNNABLE before starting this thread. 439 // Can not set it after the thread started because we do not know the 440 // exact thread state at that time. It could be in MONITOR_WAIT or 441 // in SLEEPING or some other state. 442 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 443 java_lang_Thread::RUNNABLE); 444 } 445 os::start_thread(thread); 446 } 447} 448 449// Enqueue a VM_Operation to do the job for us - sometime later 450void Thread::send_async_exception(oop java_thread, oop java_throwable) { 451 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 452 VMThread::execute(vm_stop); 453} 454 455 456// 457// Check if an external suspend request has completed (or has been 458// cancelled). Returns true if the thread is externally suspended and 459// false otherwise. 460// 461// The bits parameter returns information about the code path through 462// the routine. Useful for debugging: 463// 464// set in is_ext_suspend_completed(): 465// 0x00000001 - routine was entered 466// 0x00000010 - routine return false at end 467// 0x00000100 - thread exited (return false) 468// 0x00000200 - suspend request cancelled (return false) 469// 0x00000400 - thread suspended (return true) 470// 0x00001000 - thread is in a suspend equivalent state (return true) 471// 0x00002000 - thread is native and walkable (return true) 472// 0x00004000 - thread is native_trans and walkable (needed retry) 473// 474// set in wait_for_ext_suspend_completion(): 475// 0x00010000 - routine was entered 476// 0x00020000 - suspend request cancelled before loop (return false) 477// 0x00040000 - thread suspended before loop (return true) 478// 0x00080000 - suspend request cancelled in loop (return false) 479// 0x00100000 - thread suspended in loop (return true) 480// 0x00200000 - suspend not completed during retry loop (return false) 481// 482 483// Helper class for tracing suspend wait debug bits. 484// 485// 0x00000100 indicates that the target thread exited before it could 486// self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 487// 0x00080000 each indicate a cancelled suspend request so they don't 488// count as wait failures either. 489#define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 490 491class TraceSuspendDebugBits : public StackObj { 492 private: 493 JavaThread * jt; 494 bool is_wait; 495 bool called_by_wait; // meaningful when !is_wait 496 uint32_t * bits; 497 498 public: 499 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 500 uint32_t *_bits) { 501 jt = _jt; 502 is_wait = _is_wait; 503 called_by_wait = _called_by_wait; 504 bits = _bits; 505 } 506 507 ~TraceSuspendDebugBits() { 508 if (!is_wait) { 509#if 1 510 // By default, don't trace bits for is_ext_suspend_completed() calls. 511 // That trace is very chatty. 512 return; 513#else 514 if (!called_by_wait) { 515 // If tracing for is_ext_suspend_completed() is enabled, then only 516 // trace calls to it from wait_for_ext_suspend_completion() 517 return; 518 } 519#endif 520 } 521 522 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 523 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 524 MutexLocker ml(Threads_lock); // needed for get_thread_name() 525 ResourceMark rm; 526 527 tty->print_cr( 528 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 529 jt->get_thread_name(), *bits); 530 531 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 532 } 533 } 534 } 535}; 536#undef DEBUG_FALSE_BITS 537 538 539bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 540 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 541 542 bool did_trans_retry = false; // only do thread_in_native_trans retry once 543 bool do_trans_retry; // flag to force the retry 544 545 *bits |= 0x00000001; 546 547 do { 548 do_trans_retry = false; 549 550 if (is_exiting()) { 551 // Thread is in the process of exiting. This is always checked 552 // first to reduce the risk of dereferencing a freed JavaThread. 553 *bits |= 0x00000100; 554 return false; 555 } 556 557 if (!is_external_suspend()) { 558 // Suspend request is cancelled. This is always checked before 559 // is_ext_suspended() to reduce the risk of a rogue resume 560 // confusing the thread that made the suspend request. 561 *bits |= 0x00000200; 562 return false; 563 } 564 565 if (is_ext_suspended()) { 566 // thread is suspended 567 *bits |= 0x00000400; 568 return true; 569 } 570 571 // Now that we no longer do hard suspends of threads running 572 // native code, the target thread can be changing thread state 573 // while we are in this routine: 574 // 575 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 576 // 577 // We save a copy of the thread state as observed at this moment 578 // and make our decision about suspend completeness based on the 579 // copy. This closes the race where the thread state is seen as 580 // _thread_in_native_trans in the if-thread_blocked check, but is 581 // seen as _thread_blocked in if-thread_in_native_trans check. 582 JavaThreadState save_state = thread_state(); 583 584 if (save_state == _thread_blocked && is_suspend_equivalent()) { 585 // If the thread's state is _thread_blocked and this blocking 586 // condition is known to be equivalent to a suspend, then we can 587 // consider the thread to be externally suspended. This means that 588 // the code that sets _thread_blocked has been modified to do 589 // self-suspension if the blocking condition releases. We also 590 // used to check for CONDVAR_WAIT here, but that is now covered by 591 // the _thread_blocked with self-suspension check. 592 // 593 // Return true since we wouldn't be here unless there was still an 594 // external suspend request. 595 *bits |= 0x00001000; 596 return true; 597 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 598 // Threads running native code will self-suspend on native==>VM/Java 599 // transitions. If its stack is walkable (should always be the case 600 // unless this function is called before the actual java_suspend() 601 // call), then the wait is done. 602 *bits |= 0x00002000; 603 return true; 604 } else if (!called_by_wait && !did_trans_retry && 605 save_state == _thread_in_native_trans && 606 frame_anchor()->walkable()) { 607 // The thread is transitioning from thread_in_native to another 608 // thread state. check_safepoint_and_suspend_for_native_trans() 609 // will force the thread to self-suspend. If it hasn't gotten 610 // there yet we may have caught the thread in-between the native 611 // code check above and the self-suspend. Lucky us. If we were 612 // called by wait_for_ext_suspend_completion(), then it 613 // will be doing the retries so we don't have to. 614 // 615 // Since we use the saved thread state in the if-statement above, 616 // there is a chance that the thread has already transitioned to 617 // _thread_blocked by the time we get here. In that case, we will 618 // make a single unnecessary pass through the logic below. This 619 // doesn't hurt anything since we still do the trans retry. 620 621 *bits |= 0x00004000; 622 623 // Once the thread leaves thread_in_native_trans for another 624 // thread state, we break out of this retry loop. We shouldn't 625 // need this flag to prevent us from getting back here, but 626 // sometimes paranoia is good. 627 did_trans_retry = true; 628 629 // We wait for the thread to transition to a more usable state. 630 for (int i = 1; i <= SuspendRetryCount; i++) { 631 // We used to do an "os::yield_all(i)" call here with the intention 632 // that yielding would increase on each retry. However, the parameter 633 // is ignored on Linux which means the yield didn't scale up. Waiting 634 // on the SR_lock below provides a much more predictable scale up for 635 // the delay. It also provides a simple/direct point to check for any 636 // safepoint requests from the VMThread 637 638 // temporarily drops SR_lock while doing wait with safepoint check 639 // (if we're a JavaThread - the WatcherThread can also call this) 640 // and increase delay with each retry 641 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 642 643 // check the actual thread state instead of what we saved above 644 if (thread_state() != _thread_in_native_trans) { 645 // the thread has transitioned to another thread state so 646 // try all the checks (except this one) one more time. 647 do_trans_retry = true; 648 break; 649 } 650 } // end retry loop 651 652 653 } 654 } while (do_trans_retry); 655 656 *bits |= 0x00000010; 657 return false; 658} 659 660// 661// Wait for an external suspend request to complete (or be cancelled). 662// Returns true if the thread is externally suspended and false otherwise. 663// 664bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 665 uint32_t *bits) { 666 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 667 false /* !called_by_wait */, bits); 668 669 // local flag copies to minimize SR_lock hold time 670 bool is_suspended; 671 bool pending; 672 uint32_t reset_bits; 673 674 // set a marker so is_ext_suspend_completed() knows we are the caller 675 *bits |= 0x00010000; 676 677 // We use reset_bits to reinitialize the bits value at the top of 678 // each retry loop. This allows the caller to make use of any 679 // unused bits for their own marking purposes. 680 reset_bits = *bits; 681 682 { 683 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 684 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 685 delay, bits); 686 pending = is_external_suspend(); 687 } 688 // must release SR_lock to allow suspension to complete 689 690 if (!pending) { 691 // A cancelled suspend request is the only false return from 692 // is_ext_suspend_completed() that keeps us from entering the 693 // retry loop. 694 *bits |= 0x00020000; 695 return false; 696 } 697 698 if (is_suspended) { 699 *bits |= 0x00040000; 700 return true; 701 } 702 703 for (int i = 1; i <= retries; i++) { 704 *bits = reset_bits; // reinit to only track last retry 705 706 // We used to do an "os::yield_all(i)" call here with the intention 707 // that yielding would increase on each retry. However, the parameter 708 // is ignored on Linux which means the yield didn't scale up. Waiting 709 // on the SR_lock below provides a much more predictable scale up for 710 // the delay. It also provides a simple/direct point to check for any 711 // safepoint requests from the VMThread 712 713 { 714 MutexLocker ml(SR_lock()); 715 // wait with safepoint check (if we're a JavaThread - the WatcherThread 716 // can also call this) and increase delay with each retry 717 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 718 719 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 720 delay, bits); 721 722 // It is possible for the external suspend request to be cancelled 723 // (by a resume) before the actual suspend operation is completed. 724 // Refresh our local copy to see if we still need to wait. 725 pending = is_external_suspend(); 726 } 727 728 if (!pending) { 729 // A cancelled suspend request is the only false return from 730 // is_ext_suspend_completed() that keeps us from staying in the 731 // retry loop. 732 *bits |= 0x00080000; 733 return false; 734 } 735 736 if (is_suspended) { 737 *bits |= 0x00100000; 738 return true; 739 } 740 } // end retry loop 741 742 // thread did not suspend after all our retries 743 *bits |= 0x00200000; 744 return false; 745} 746 747#ifndef PRODUCT 748void JavaThread::record_jump(address target, address instr, const char* file, int line) { 749 750 // This should not need to be atomic as the only way for simultaneous 751 // updates is via interrupts. Even then this should be rare or non-existent 752 // and we don't care that much anyway. 753 754 int index = _jmp_ring_index; 755 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 756 _jmp_ring[index]._target = (intptr_t) target; 757 _jmp_ring[index]._instruction = (intptr_t) instr; 758 _jmp_ring[index]._file = file; 759 _jmp_ring[index]._line = line; 760} 761#endif /* PRODUCT */ 762 763// Called by flat profiler 764// Callers have already called wait_for_ext_suspend_completion 765// The assertion for that is currently too complex to put here: 766bool JavaThread::profile_last_Java_frame(frame* _fr) { 767 bool gotframe = false; 768 // self suspension saves needed state. 769 if (has_last_Java_frame() && _anchor.walkable()) { 770 *_fr = pd_last_frame(); 771 gotframe = true; 772 } 773 return gotframe; 774} 775 776void Thread::interrupt(Thread* thread) { 777 trace("interrupt", thread); 778 debug_only(check_for_dangling_thread_pointer(thread);) 779 os::interrupt(thread); 780} 781 782bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 783 trace("is_interrupted", thread); 784 debug_only(check_for_dangling_thread_pointer(thread);) 785 // Note: If clear_interrupted==false, this simply fetches and 786 // returns the value of the field osthread()->interrupted(). 787 return os::is_interrupted(thread, clear_interrupted); 788} 789 790 791// GC Support 792bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 793 jint thread_parity = _oops_do_parity; 794 if (thread_parity != strong_roots_parity) { 795 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 796 if (res == thread_parity) { 797 return true; 798 } else { 799 guarantee(res == strong_roots_parity, "Or else what?"); 800 assert(SharedHeap::heap()->workers()->active_workers() > 0, 801 "Should only fail when parallel."); 802 return false; 803 } 804 } 805 assert(SharedHeap::heap()->workers()->active_workers() > 0, 806 "Should only fail when parallel."); 807 return false; 808} 809 810void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 811 active_handles()->oops_do(f); 812 // Do oop for ThreadShadow 813 f->do_oop((oop*)&_pending_exception); 814 handle_area()->oops_do(f); 815} 816 817void Thread::nmethods_do(CodeBlobClosure* cf) { 818 // no nmethods in a generic thread... 819} 820 821void Thread::metadata_do(void f(Metadata*)) { 822 if (metadata_handles() != NULL) { 823 for (int i = 0; i< metadata_handles()->length(); i++) { 824 f(metadata_handles()->at(i)); 825 } 826 } 827} 828 829void Thread::print_on(outputStream* st) const { 830 // get_priority assumes osthread initialized 831 if (osthread() != NULL) { 832 int os_prio; 833 if (os::get_native_priority(this, &os_prio) == OS_OK) { 834 st->print("os_prio=%d ", os_prio); 835 } 836 st->print("tid=" INTPTR_FORMAT " ", this); 837 osthread()->print_on(st); 838 } 839 debug_only(if (WizardMode) print_owned_locks_on(st);) 840} 841 842// Thread::print_on_error() is called by fatal error handler. Don't use 843// any lock or allocate memory. 844void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 845 if (is_VM_thread()) st->print("VMThread"); 846 else if (is_Compiler_thread()) st->print("CompilerThread"); 847 else if (is_Java_thread()) st->print("JavaThread"); 848 else if (is_GC_task_thread()) st->print("GCTaskThread"); 849 else if (is_Watcher_thread()) st->print("WatcherThread"); 850 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 851 else st->print("Thread"); 852 853 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 854 _stack_base - _stack_size, _stack_base); 855 856 if (osthread()) { 857 st->print(" [id=%d]", osthread()->thread_id()); 858 } 859} 860 861#ifdef ASSERT 862void Thread::print_owned_locks_on(outputStream* st) const { 863 Monitor *cur = _owned_locks; 864 if (cur == NULL) { 865 st->print(" (no locks) "); 866 } else { 867 st->print_cr(" Locks owned:"); 868 while(cur) { 869 cur->print_on(st); 870 cur = cur->next(); 871 } 872 } 873} 874 875static int ref_use_count = 0; 876 877bool Thread::owns_locks_but_compiled_lock() const { 878 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 879 if (cur != Compile_lock) return true; 880 } 881 return false; 882} 883 884 885#endif 886 887#ifndef PRODUCT 888 889// The flag: potential_vm_operation notifies if this particular safepoint state could potential 890// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 891// no threads which allow_vm_block's are held 892void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 893 // Check if current thread is allowed to block at a safepoint 894 if (!(_allow_safepoint_count == 0)) 895 fatal("Possible safepoint reached by thread that does not allow it"); 896 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 897 fatal("LEAF method calling lock?"); 898 } 899 900#ifdef ASSERT 901 if (potential_vm_operation && is_Java_thread() 902 && !Universe::is_bootstrapping()) { 903 // Make sure we do not hold any locks that the VM thread also uses. 904 // This could potentially lead to deadlocks 905 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 906 // Threads_lock is special, since the safepoint synchronization will not start before this is 907 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 908 // since it is used to transfer control between JavaThreads and the VMThread 909 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 910 if ( (cur->allow_vm_block() && 911 cur != Threads_lock && 912 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 913 cur != VMOperationRequest_lock && 914 cur != VMOperationQueue_lock) || 915 cur->rank() == Mutex::special) { 916 fatal(err_msg("Thread holding lock at safepoint that vm can block on: %s", cur->name())); 917 } 918 } 919 } 920 921 if (GCALotAtAllSafepoints) { 922 // We could enter a safepoint here and thus have a gc 923 InterfaceSupport::check_gc_alot(); 924 } 925#endif 926} 927#endif 928 929bool Thread::is_in_stack(address adr) const { 930 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 931 address end = os::current_stack_pointer(); 932 // Allow non Java threads to call this without stack_base 933 if (_stack_base == NULL) return true; 934 if (stack_base() >= adr && adr >= end) return true; 935 936 return false; 937} 938 939 940bool Thread::is_in_usable_stack(address adr) const { 941 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 942 size_t usable_stack_size = _stack_size - stack_guard_size; 943 944 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 945} 946 947 948// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 949// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 950// used for compilation in the future. If that change is made, the need for these methods 951// should be revisited, and they should be removed if possible. 952 953bool Thread::is_lock_owned(address adr) const { 954 return on_local_stack(adr); 955} 956 957bool Thread::set_as_starting_thread() { 958 // NOTE: this must be called inside the main thread. 959 return os::create_main_thread((JavaThread*)this); 960} 961 962static void initialize_class(Symbol* class_name, TRAPS) { 963 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 964 InstanceKlass::cast(klass)->initialize(CHECK); 965} 966 967 968// Creates the initial ThreadGroup 969static Handle create_initial_thread_group(TRAPS) { 970 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 971 instanceKlassHandle klass (THREAD, k); 972 973 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 974 { 975 JavaValue result(T_VOID); 976 JavaCalls::call_special(&result, 977 system_instance, 978 klass, 979 vmSymbols::object_initializer_name(), 980 vmSymbols::void_method_signature(), 981 CHECK_NH); 982 } 983 Universe::set_system_thread_group(system_instance()); 984 985 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 986 { 987 JavaValue result(T_VOID); 988 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 989 JavaCalls::call_special(&result, 990 main_instance, 991 klass, 992 vmSymbols::object_initializer_name(), 993 vmSymbols::threadgroup_string_void_signature(), 994 system_instance, 995 string, 996 CHECK_NH); 997 } 998 return main_instance; 999} 1000 1001// Creates the initial Thread 1002static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1003 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1004 instanceKlassHandle klass (THREAD, k); 1005 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1006 1007 java_lang_Thread::set_thread(thread_oop(), thread); 1008 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1009 thread->set_threadObj(thread_oop()); 1010 1011 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1012 1013 JavaValue result(T_VOID); 1014 JavaCalls::call_special(&result, thread_oop, 1015 klass, 1016 vmSymbols::object_initializer_name(), 1017 vmSymbols::threadgroup_string_void_signature(), 1018 thread_group, 1019 string, 1020 CHECK_NULL); 1021 return thread_oop(); 1022} 1023 1024static void call_initializeSystemClass(TRAPS) { 1025 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1026 instanceKlassHandle klass (THREAD, k); 1027 1028 JavaValue result(T_VOID); 1029 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1030 vmSymbols::void_method_signature(), CHECK); 1031} 1032 1033char java_runtime_name[128] = ""; 1034char java_runtime_version[128] = ""; 1035 1036// extract the JRE name from sun.misc.Version.java_runtime_name 1037static const char* get_java_runtime_name(TRAPS) { 1038 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1039 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1040 fieldDescriptor fd; 1041 bool found = k != NULL && 1042 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1043 vmSymbols::string_signature(), &fd); 1044 if (found) { 1045 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1046 if (name_oop == NULL) 1047 return NULL; 1048 const char* name = java_lang_String::as_utf8_string(name_oop, 1049 java_runtime_name, 1050 sizeof(java_runtime_name)); 1051 return name; 1052 } else { 1053 return NULL; 1054 } 1055} 1056 1057// extract the JRE version from sun.misc.Version.java_runtime_version 1058static const char* get_java_runtime_version(TRAPS) { 1059 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1060 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1061 fieldDescriptor fd; 1062 bool found = k != NULL && 1063 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1064 vmSymbols::string_signature(), &fd); 1065 if (found) { 1066 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1067 if (name_oop == NULL) 1068 return NULL; 1069 const char* name = java_lang_String::as_utf8_string(name_oop, 1070 java_runtime_version, 1071 sizeof(java_runtime_version)); 1072 return name; 1073 } else { 1074 return NULL; 1075 } 1076} 1077 1078// General purpose hook into Java code, run once when the VM is initialized. 1079// The Java library method itself may be changed independently from the VM. 1080static void call_postVMInitHook(TRAPS) { 1081 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1082 instanceKlassHandle klass (THREAD, k); 1083 if (klass.not_null()) { 1084 JavaValue result(T_VOID); 1085 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1086 vmSymbols::void_method_signature(), 1087 CHECK); 1088 } 1089} 1090 1091static void reset_vm_info_property(TRAPS) { 1092 // the vm info string 1093 ResourceMark rm(THREAD); 1094 const char *vm_info = VM_Version::vm_info_string(); 1095 1096 // java.lang.System class 1097 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1098 instanceKlassHandle klass (THREAD, k); 1099 1100 // setProperty arguments 1101 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1102 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1103 1104 // return value 1105 JavaValue r(T_OBJECT); 1106 1107 // public static String setProperty(String key, String value); 1108 JavaCalls::call_static(&r, 1109 klass, 1110 vmSymbols::setProperty_name(), 1111 vmSymbols::string_string_string_signature(), 1112 key_str, 1113 value_str, 1114 CHECK); 1115} 1116 1117 1118void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1119 assert(thread_group.not_null(), "thread group should be specified"); 1120 assert(threadObj() == NULL, "should only create Java thread object once"); 1121 1122 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1123 instanceKlassHandle klass (THREAD, k); 1124 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1125 1126 java_lang_Thread::set_thread(thread_oop(), this); 1127 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1128 set_threadObj(thread_oop()); 1129 1130 JavaValue result(T_VOID); 1131 if (thread_name != NULL) { 1132 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1133 // Thread gets assigned specified name and null target 1134 JavaCalls::call_special(&result, 1135 thread_oop, 1136 klass, 1137 vmSymbols::object_initializer_name(), 1138 vmSymbols::threadgroup_string_void_signature(), 1139 thread_group, // Argument 1 1140 name, // Argument 2 1141 THREAD); 1142 } else { 1143 // Thread gets assigned name "Thread-nnn" and null target 1144 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1145 JavaCalls::call_special(&result, 1146 thread_oop, 1147 klass, 1148 vmSymbols::object_initializer_name(), 1149 vmSymbols::threadgroup_runnable_void_signature(), 1150 thread_group, // Argument 1 1151 Handle(), // Argument 2 1152 THREAD); 1153 } 1154 1155 1156 if (daemon) { 1157 java_lang_Thread::set_daemon(thread_oop()); 1158 } 1159 1160 if (HAS_PENDING_EXCEPTION) { 1161 return; 1162 } 1163 1164 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1165 Handle threadObj(this, this->threadObj()); 1166 1167 JavaCalls::call_special(&result, 1168 thread_group, 1169 group, 1170 vmSymbols::add_method_name(), 1171 vmSymbols::thread_void_signature(), 1172 threadObj, // Arg 1 1173 THREAD); 1174 1175 1176} 1177 1178// NamedThread -- non-JavaThread subclasses with multiple 1179// uniquely named instances should derive from this. 1180NamedThread::NamedThread() : Thread() { 1181 _name = NULL; 1182 _processed_thread = NULL; 1183} 1184 1185NamedThread::~NamedThread() { 1186 if (_name != NULL) { 1187 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1188 _name = NULL; 1189 } 1190} 1191 1192void NamedThread::set_name(const char* format, ...) { 1193 guarantee(_name == NULL, "Only get to set name once."); 1194 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1195 guarantee(_name != NULL, "alloc failure"); 1196 va_list ap; 1197 va_start(ap, format); 1198 jio_vsnprintf(_name, max_name_len, format, ap); 1199 va_end(ap); 1200} 1201 1202void NamedThread::print_on(outputStream* st) const { 1203 st->print("\"%s\" ", name()); 1204 Thread::print_on(st); 1205 st->cr(); 1206} 1207 1208 1209// ======= WatcherThread ======== 1210 1211// The watcher thread exists to simulate timer interrupts. It should 1212// be replaced by an abstraction over whatever native support for 1213// timer interrupts exists on the platform. 1214 1215WatcherThread* WatcherThread::_watcher_thread = NULL; 1216bool WatcherThread::_startable = false; 1217volatile bool WatcherThread::_should_terminate = false; 1218 1219WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1220 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1221 if (os::create_thread(this, os::watcher_thread)) { 1222 _watcher_thread = this; 1223 1224 // Set the watcher thread to the highest OS priority which should not be 1225 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1226 // is created. The only normal thread using this priority is the reference 1227 // handler thread, which runs for very short intervals only. 1228 // If the VMThread's priority is not lower than the WatcherThread profiling 1229 // will be inaccurate. 1230 os::set_priority(this, MaxPriority); 1231 if (!DisableStartThread) { 1232 os::start_thread(this); 1233 } 1234 } 1235} 1236 1237int WatcherThread::sleep() const { 1238 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1239 1240 // remaining will be zero if there are no tasks, 1241 // causing the WatcherThread to sleep until a task is 1242 // enrolled 1243 int remaining = PeriodicTask::time_to_wait(); 1244 int time_slept = 0; 1245 1246 // we expect this to timeout - we only ever get unparked when 1247 // we should terminate or when a new task has been enrolled 1248 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1249 1250 jlong time_before_loop = os::javaTimeNanos(); 1251 1252 for (;;) { 1253 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1254 jlong now = os::javaTimeNanos(); 1255 1256 if (remaining == 0) { 1257 // if we didn't have any tasks we could have waited for a long time 1258 // consider the time_slept zero and reset time_before_loop 1259 time_slept = 0; 1260 time_before_loop = now; 1261 } else { 1262 // need to recalculate since we might have new tasks in _tasks 1263 time_slept = (int) ((now - time_before_loop) / 1000000); 1264 } 1265 1266 // Change to task list or spurious wakeup of some kind 1267 if (timedout || _should_terminate) { 1268 break; 1269 } 1270 1271 remaining = PeriodicTask::time_to_wait(); 1272 if (remaining == 0) { 1273 // Last task was just disenrolled so loop around and wait until 1274 // another task gets enrolled 1275 continue; 1276 } 1277 1278 remaining -= time_slept; 1279 if (remaining <= 0) 1280 break; 1281 } 1282 1283 return time_slept; 1284} 1285 1286void WatcherThread::run() { 1287 assert(this == watcher_thread(), "just checking"); 1288 1289 this->record_stack_base_and_size(); 1290 this->initialize_thread_local_storage(); 1291 this->set_active_handles(JNIHandleBlock::allocate_block()); 1292 while(!_should_terminate) { 1293 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1294 assert(watcher_thread() == this, "thread consistency check"); 1295 1296 // Calculate how long it'll be until the next PeriodicTask work 1297 // should be done, and sleep that amount of time. 1298 int time_waited = sleep(); 1299 1300 if (is_error_reported()) { 1301 // A fatal error has happened, the error handler(VMError::report_and_die) 1302 // should abort JVM after creating an error log file. However in some 1303 // rare cases, the error handler itself might deadlock. Here we try to 1304 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1305 // 1306 // This code is in WatcherThread because WatcherThread wakes up 1307 // periodically so the fatal error handler doesn't need to do anything; 1308 // also because the WatcherThread is less likely to crash than other 1309 // threads. 1310 1311 for (;;) { 1312 if (!ShowMessageBoxOnError 1313 && (OnError == NULL || OnError[0] == '\0') 1314 && Arguments::abort_hook() == NULL) { 1315 os::sleep(this, 2 * 60 * 1000, false); 1316 fdStream err(defaultStream::output_fd()); 1317 err.print_raw_cr("# [ timer expired, abort... ]"); 1318 // skip atexit/vm_exit/vm_abort hooks 1319 os::die(); 1320 } 1321 1322 // Wake up 5 seconds later, the fatal handler may reset OnError or 1323 // ShowMessageBoxOnError when it is ready to abort. 1324 os::sleep(this, 5 * 1000, false); 1325 } 1326 } 1327 1328 PeriodicTask::real_time_tick(time_waited); 1329 } 1330 1331 // Signal that it is terminated 1332 { 1333 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1334 _watcher_thread = NULL; 1335 Terminator_lock->notify(); 1336 } 1337 1338 // Thread destructor usually does this.. 1339 ThreadLocalStorage::set_thread(NULL); 1340} 1341 1342void WatcherThread::start() { 1343 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1344 1345 if (watcher_thread() == NULL && _startable) { 1346 _should_terminate = false; 1347 // Create the single instance of WatcherThread 1348 new WatcherThread(); 1349 } 1350} 1351 1352void WatcherThread::make_startable() { 1353 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1354 _startable = true; 1355} 1356 1357void WatcherThread::stop() { 1358 { 1359 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1360 _should_terminate = true; 1361 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1362 1363 WatcherThread* watcher = watcher_thread(); 1364 if (watcher != NULL) 1365 watcher->unpark(); 1366 } 1367 1368 // it is ok to take late safepoints here, if needed 1369 MutexLocker mu(Terminator_lock); 1370 1371 while(watcher_thread() != NULL) { 1372 // This wait should make safepoint checks, wait without a timeout, 1373 // and wait as a suspend-equivalent condition. 1374 // 1375 // Note: If the FlatProfiler is running, then this thread is waiting 1376 // for the WatcherThread to terminate and the WatcherThread, via the 1377 // FlatProfiler task, is waiting for the external suspend request on 1378 // this thread to complete. wait_for_ext_suspend_completion() will 1379 // eventually timeout, but that takes time. Making this wait a 1380 // suspend-equivalent condition solves that timeout problem. 1381 // 1382 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1383 Mutex::_as_suspend_equivalent_flag); 1384 } 1385} 1386 1387void WatcherThread::unpark() { 1388 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1389 PeriodicTask_lock->notify(); 1390} 1391 1392void WatcherThread::print_on(outputStream* st) const { 1393 st->print("\"%s\" ", name()); 1394 Thread::print_on(st); 1395 st->cr(); 1396} 1397 1398// ======= JavaThread ======== 1399 1400// A JavaThread is a normal Java thread 1401 1402void JavaThread::initialize() { 1403 // Initialize fields 1404 1405 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1406 set_claimed_par_id(UINT_MAX); 1407 1408 set_saved_exception_pc(NULL); 1409 set_threadObj(NULL); 1410 _anchor.clear(); 1411 set_entry_point(NULL); 1412 set_jni_functions(jni_functions()); 1413 set_callee_target(NULL); 1414 set_vm_result(NULL); 1415 set_vm_result_2(NULL); 1416 set_vframe_array_head(NULL); 1417 set_vframe_array_last(NULL); 1418 set_deferred_locals(NULL); 1419 set_deopt_mark(NULL); 1420 set_deopt_nmethod(NULL); 1421 clear_must_deopt_id(); 1422 set_monitor_chunks(NULL); 1423 set_next(NULL); 1424 set_thread_state(_thread_new); 1425#if INCLUDE_NMT 1426 set_recorder(NULL); 1427#endif 1428 _terminated = _not_terminated; 1429 _privileged_stack_top = NULL; 1430 _array_for_gc = NULL; 1431 _suspend_equivalent = false; 1432 _in_deopt_handler = 0; 1433 _doing_unsafe_access = false; 1434 _stack_guard_state = stack_guard_unused; 1435 (void)const_cast<oop&>(_exception_oop = NULL); 1436 _exception_pc = 0; 1437 _exception_handler_pc = 0; 1438 _is_method_handle_return = 0; 1439 _jvmti_thread_state= NULL; 1440 _should_post_on_exceptions_flag = JNI_FALSE; 1441 _jvmti_get_loaded_classes_closure = NULL; 1442 _interp_only_mode = 0; 1443 _special_runtime_exit_condition = _no_async_condition; 1444 _pending_async_exception = NULL; 1445 _thread_stat = NULL; 1446 _thread_stat = new ThreadStatistics(); 1447 _blocked_on_compilation = false; 1448 _jni_active_critical = 0; 1449 _do_not_unlock_if_synchronized = false; 1450 _cached_monitor_info = NULL; 1451 _parker = Parker::Allocate(this) ; 1452 1453#ifndef PRODUCT 1454 _jmp_ring_index = 0; 1455 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1456 record_jump(NULL, NULL, NULL, 0); 1457 } 1458#endif /* PRODUCT */ 1459 1460 set_thread_profiler(NULL); 1461 if (FlatProfiler::is_active()) { 1462 // This is where we would decide to either give each thread it's own profiler 1463 // or use one global one from FlatProfiler, 1464 // or up to some count of the number of profiled threads, etc. 1465 ThreadProfiler* pp = new ThreadProfiler(); 1466 pp->engage(); 1467 set_thread_profiler(pp); 1468 } 1469 1470 // Setup safepoint state info for this thread 1471 ThreadSafepointState::create(this); 1472 1473 debug_only(_java_call_counter = 0); 1474 1475 // JVMTI PopFrame support 1476 _popframe_condition = popframe_inactive; 1477 _popframe_preserved_args = NULL; 1478 _popframe_preserved_args_size = 0; 1479 1480 pd_initialize(); 1481} 1482 1483#if INCLUDE_ALL_GCS 1484SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1485DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1486#endif // INCLUDE_ALL_GCS 1487 1488JavaThread::JavaThread(bool is_attaching_via_jni) : 1489 Thread() 1490#if INCLUDE_ALL_GCS 1491 , _satb_mark_queue(&_satb_mark_queue_set), 1492 _dirty_card_queue(&_dirty_card_queue_set) 1493#endif // INCLUDE_ALL_GCS 1494{ 1495 initialize(); 1496 if (is_attaching_via_jni) { 1497 _jni_attach_state = _attaching_via_jni; 1498 } else { 1499 _jni_attach_state = _not_attaching_via_jni; 1500 } 1501 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1502 _safepoint_visible = false; 1503} 1504 1505bool JavaThread::reguard_stack(address cur_sp) { 1506 if (_stack_guard_state != stack_guard_yellow_disabled) { 1507 return true; // Stack already guarded or guard pages not needed. 1508 } 1509 1510 if (register_stack_overflow()) { 1511 // For those architectures which have separate register and 1512 // memory stacks, we must check the register stack to see if 1513 // it has overflowed. 1514 return false; 1515 } 1516 1517 // Java code never executes within the yellow zone: the latter is only 1518 // there to provoke an exception during stack banging. If java code 1519 // is executing there, either StackShadowPages should be larger, or 1520 // some exception code in c1, c2 or the interpreter isn't unwinding 1521 // when it should. 1522 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1523 1524 enable_stack_yellow_zone(); 1525 return true; 1526} 1527 1528bool JavaThread::reguard_stack(void) { 1529 return reguard_stack(os::current_stack_pointer()); 1530} 1531 1532 1533void JavaThread::block_if_vm_exited() { 1534 if (_terminated == _vm_exited) { 1535 // _vm_exited is set at safepoint, and Threads_lock is never released 1536 // we will block here forever 1537 Threads_lock->lock_without_safepoint_check(); 1538 ShouldNotReachHere(); 1539 } 1540} 1541 1542 1543// Remove this ifdef when C1 is ported to the compiler interface. 1544static void compiler_thread_entry(JavaThread* thread, TRAPS); 1545 1546JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1547 Thread() 1548#if INCLUDE_ALL_GCS 1549 , _satb_mark_queue(&_satb_mark_queue_set), 1550 _dirty_card_queue(&_dirty_card_queue_set) 1551#endif // INCLUDE_ALL_GCS 1552{ 1553 if (TraceThreadEvents) { 1554 tty->print_cr("creating thread %p", this); 1555 } 1556 initialize(); 1557 _jni_attach_state = _not_attaching_via_jni; 1558 set_entry_point(entry_point); 1559 // Create the native thread itself. 1560 // %note runtime_23 1561 os::ThreadType thr_type = os::java_thread; 1562 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1563 os::java_thread; 1564 os::create_thread(this, thr_type, stack_sz); 1565 _safepoint_visible = false; 1566 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1567 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1568 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1569 // the exception consists of creating the exception object & initializing it, initialization 1570 // will leave the VM via a JavaCall and then all locks must be unlocked). 1571 // 1572 // The thread is still suspended when we reach here. Thread must be explicit started 1573 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1574 // by calling Threads:add. The reason why this is not done here, is because the thread 1575 // object must be fully initialized (take a look at JVM_Start) 1576} 1577 1578JavaThread::~JavaThread() { 1579 if (TraceThreadEvents) { 1580 tty->print_cr("terminate thread %p", this); 1581 } 1582 1583 // By now, this thread should already be invisible to safepoint, 1584 // and its per-thread recorder also collected. 1585 assert(!is_safepoint_visible(), "wrong state"); 1586#if INCLUDE_NMT 1587 assert(get_recorder() == NULL, "Already collected"); 1588#endif // INCLUDE_NMT 1589 1590 // JSR166 -- return the parker to the free list 1591 Parker::Release(_parker); 1592 _parker = NULL ; 1593 1594 // Free any remaining previous UnrollBlock 1595 vframeArray* old_array = vframe_array_last(); 1596 1597 if (old_array != NULL) { 1598 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1599 old_array->set_unroll_block(NULL); 1600 delete old_info; 1601 delete old_array; 1602 } 1603 1604 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1605 if (deferred != NULL) { 1606 // This can only happen if thread is destroyed before deoptimization occurs. 1607 assert(deferred->length() != 0, "empty array!"); 1608 do { 1609 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1610 deferred->remove_at(0); 1611 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1612 delete dlv; 1613 } while (deferred->length() != 0); 1614 delete deferred; 1615 } 1616 1617 // All Java related clean up happens in exit 1618 ThreadSafepointState::destroy(this); 1619 if (_thread_profiler != NULL) delete _thread_profiler; 1620 if (_thread_stat != NULL) delete _thread_stat; 1621} 1622 1623 1624// The first routine called by a new Java thread 1625void JavaThread::run() { 1626 // initialize thread-local alloc buffer related fields 1627 this->initialize_tlab(); 1628 1629 // used to test validity of stack trace backs 1630 this->record_base_of_stack_pointer(); 1631 1632 // Record real stack base and size. 1633 this->record_stack_base_and_size(); 1634 1635 // Initialize thread local storage; set before calling MutexLocker 1636 this->initialize_thread_local_storage(); 1637 1638 this->create_stack_guard_pages(); 1639 1640 this->cache_global_variables(); 1641 1642 // Thread is now sufficient initialized to be handled by the safepoint code as being 1643 // in the VM. Change thread state from _thread_new to _thread_in_vm 1644 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1645 1646 assert(JavaThread::current() == this, "sanity check"); 1647 assert(!Thread::current()->owns_locks(), "sanity check"); 1648 1649 DTRACE_THREAD_PROBE(start, this); 1650 1651 // This operation might block. We call that after all safepoint checks for a new thread has 1652 // been completed. 1653 this->set_active_handles(JNIHandleBlock::allocate_block()); 1654 1655 if (JvmtiExport::should_post_thread_life()) { 1656 JvmtiExport::post_thread_start(this); 1657 } 1658 1659 EventThreadStart event; 1660 if (event.should_commit()) { 1661 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1662 event.commit(); 1663 } 1664 1665 // We call another function to do the rest so we are sure that the stack addresses used 1666 // from there will be lower than the stack base just computed 1667 thread_main_inner(); 1668 1669 // Note, thread is no longer valid at this point! 1670} 1671 1672 1673void JavaThread::thread_main_inner() { 1674 assert(JavaThread::current() == this, "sanity check"); 1675 assert(this->threadObj() != NULL, "just checking"); 1676 1677 // Execute thread entry point unless this thread has a pending exception 1678 // or has been stopped before starting. 1679 // Note: Due to JVM_StopThread we can have pending exceptions already! 1680 if (!this->has_pending_exception() && 1681 !java_lang_Thread::is_stillborn(this->threadObj())) { 1682 { 1683 ResourceMark rm(this); 1684 this->set_native_thread_name(this->get_thread_name()); 1685 } 1686 HandleMark hm(this); 1687 this->entry_point()(this, this); 1688 } 1689 1690 DTRACE_THREAD_PROBE(stop, this); 1691 1692 this->exit(false); 1693 delete this; 1694} 1695 1696 1697static void ensure_join(JavaThread* thread) { 1698 // We do not need to grap the Threads_lock, since we are operating on ourself. 1699 Handle threadObj(thread, thread->threadObj()); 1700 assert(threadObj.not_null(), "java thread object must exist"); 1701 ObjectLocker lock(threadObj, thread); 1702 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1703 thread->clear_pending_exception(); 1704 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1705 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1706 // Clear the native thread instance - this makes isAlive return false and allows the join() 1707 // to complete once we've done the notify_all below 1708 java_lang_Thread::set_thread(threadObj(), NULL); 1709 lock.notify_all(thread); 1710 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1711 thread->clear_pending_exception(); 1712} 1713 1714 1715// For any new cleanup additions, please check to see if they need to be applied to 1716// cleanup_failed_attach_current_thread as well. 1717void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1718 assert(this == JavaThread::current(), "thread consistency check"); 1719 1720 HandleMark hm(this); 1721 Handle uncaught_exception(this, this->pending_exception()); 1722 this->clear_pending_exception(); 1723 Handle threadObj(this, this->threadObj()); 1724 assert(threadObj.not_null(), "Java thread object should be created"); 1725 1726 if (get_thread_profiler() != NULL) { 1727 get_thread_profiler()->disengage(); 1728 ResourceMark rm; 1729 get_thread_profiler()->print(get_thread_name()); 1730 } 1731 1732 1733 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1734 { 1735 EXCEPTION_MARK; 1736 1737 CLEAR_PENDING_EXCEPTION; 1738 } 1739 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1740 // has to be fixed by a runtime query method 1741 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1742 // JSR-166: change call from from ThreadGroup.uncaughtException to 1743 // java.lang.Thread.dispatchUncaughtException 1744 if (uncaught_exception.not_null()) { 1745 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1746 { 1747 EXCEPTION_MARK; 1748 // Check if the method Thread.dispatchUncaughtException() exists. If so 1749 // call it. Otherwise we have an older library without the JSR-166 changes, 1750 // so call ThreadGroup.uncaughtException() 1751 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1752 CallInfo callinfo; 1753 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1754 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1755 vmSymbols::dispatchUncaughtException_name(), 1756 vmSymbols::throwable_void_signature(), 1757 KlassHandle(), false, false, THREAD); 1758 CLEAR_PENDING_EXCEPTION; 1759 methodHandle method = callinfo.selected_method(); 1760 if (method.not_null()) { 1761 JavaValue result(T_VOID); 1762 JavaCalls::call_virtual(&result, 1763 threadObj, thread_klass, 1764 vmSymbols::dispatchUncaughtException_name(), 1765 vmSymbols::throwable_void_signature(), 1766 uncaught_exception, 1767 THREAD); 1768 } else { 1769 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1770 JavaValue result(T_VOID); 1771 JavaCalls::call_virtual(&result, 1772 group, thread_group, 1773 vmSymbols::uncaughtException_name(), 1774 vmSymbols::thread_throwable_void_signature(), 1775 threadObj, // Arg 1 1776 uncaught_exception, // Arg 2 1777 THREAD); 1778 } 1779 if (HAS_PENDING_EXCEPTION) { 1780 ResourceMark rm(this); 1781 jio_fprintf(defaultStream::error_stream(), 1782 "\nException: %s thrown from the UncaughtExceptionHandler" 1783 " in thread \"%s\"\n", 1784 pending_exception()->klass()->external_name(), 1785 get_thread_name()); 1786 CLEAR_PENDING_EXCEPTION; 1787 } 1788 } 1789 } 1790 1791 // Called before the java thread exit since we want to read info 1792 // from java_lang_Thread object 1793 EventThreadEnd event; 1794 if (event.should_commit()) { 1795 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1796 event.commit(); 1797 } 1798 1799 // Call after last event on thread 1800 EVENT_THREAD_EXIT(this); 1801 1802 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1803 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1804 // is deprecated anyhow. 1805 if (!is_Compiler_thread()) { 1806 int count = 3; 1807 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1808 EXCEPTION_MARK; 1809 JavaValue result(T_VOID); 1810 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1811 JavaCalls::call_virtual(&result, 1812 threadObj, thread_klass, 1813 vmSymbols::exit_method_name(), 1814 vmSymbols::void_method_signature(), 1815 THREAD); 1816 CLEAR_PENDING_EXCEPTION; 1817 } 1818 } 1819 // notify JVMTI 1820 if (JvmtiExport::should_post_thread_life()) { 1821 JvmtiExport::post_thread_end(this); 1822 } 1823 1824 // We have notified the agents that we are exiting, before we go on, 1825 // we must check for a pending external suspend request and honor it 1826 // in order to not surprise the thread that made the suspend request. 1827 while (true) { 1828 { 1829 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1830 if (!is_external_suspend()) { 1831 set_terminated(_thread_exiting); 1832 ThreadService::current_thread_exiting(this); 1833 break; 1834 } 1835 // Implied else: 1836 // Things get a little tricky here. We have a pending external 1837 // suspend request, but we are holding the SR_lock so we 1838 // can't just self-suspend. So we temporarily drop the lock 1839 // and then self-suspend. 1840 } 1841 1842 ThreadBlockInVM tbivm(this); 1843 java_suspend_self(); 1844 1845 // We're done with this suspend request, but we have to loop around 1846 // and check again. Eventually we will get SR_lock without a pending 1847 // external suspend request and will be able to mark ourselves as 1848 // exiting. 1849 } 1850 // no more external suspends are allowed at this point 1851 } else { 1852 // before_exit() has already posted JVMTI THREAD_END events 1853 } 1854 1855 // Notify waiters on thread object. This has to be done after exit() is called 1856 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1857 // group should have the destroyed bit set before waiters are notified). 1858 ensure_join(this); 1859 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1860 1861 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1862 // held by this thread must be released. A detach operation must only 1863 // get here if there are no Java frames on the stack. Therefore, any 1864 // owned monitors at this point MUST be JNI-acquired monitors which are 1865 // pre-inflated and in the monitor cache. 1866 // 1867 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1868 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1869 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1870 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1871 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1872 } 1873 1874 // These things needs to be done while we are still a Java Thread. Make sure that thread 1875 // is in a consistent state, in case GC happens 1876 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1877 1878 if (active_handles() != NULL) { 1879 JNIHandleBlock* block = active_handles(); 1880 set_active_handles(NULL); 1881 JNIHandleBlock::release_block(block); 1882 } 1883 1884 if (free_handle_block() != NULL) { 1885 JNIHandleBlock* block = free_handle_block(); 1886 set_free_handle_block(NULL); 1887 JNIHandleBlock::release_block(block); 1888 } 1889 1890 // These have to be removed while this is still a valid thread. 1891 remove_stack_guard_pages(); 1892 1893 if (UseTLAB) { 1894 tlab().make_parsable(true); // retire TLAB 1895 } 1896 1897 if (JvmtiEnv::environments_might_exist()) { 1898 JvmtiExport::cleanup_thread(this); 1899 } 1900 1901 // We must flush any deferred card marks before removing a thread from 1902 // the list of active threads. 1903 Universe::heap()->flush_deferred_store_barrier(this); 1904 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1905 1906#if INCLUDE_ALL_GCS 1907 // We must flush the G1-related buffers before removing a thread 1908 // from the list of active threads. We must do this after any deferred 1909 // card marks have been flushed (above) so that any entries that are 1910 // added to the thread's dirty card queue as a result are not lost. 1911 if (UseG1GC) { 1912 flush_barrier_queues(); 1913 } 1914#endif // INCLUDE_ALL_GCS 1915 1916 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1917 Threads::remove(this); 1918} 1919 1920#if INCLUDE_ALL_GCS 1921// Flush G1-related queues. 1922void JavaThread::flush_barrier_queues() { 1923 satb_mark_queue().flush(); 1924 dirty_card_queue().flush(); 1925} 1926 1927void JavaThread::initialize_queues() { 1928 assert(!SafepointSynchronize::is_at_safepoint(), 1929 "we should not be at a safepoint"); 1930 1931 ObjPtrQueue& satb_queue = satb_mark_queue(); 1932 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1933 // The SATB queue should have been constructed with its active 1934 // field set to false. 1935 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1936 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1937 // If we are creating the thread during a marking cycle, we should 1938 // set the active field of the SATB queue to true. 1939 if (satb_queue_set.is_active()) { 1940 satb_queue.set_active(true); 1941 } 1942 1943 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1944 // The dirty card queue should have been constructed with its 1945 // active field set to true. 1946 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1947} 1948#endif // INCLUDE_ALL_GCS 1949 1950void JavaThread::cleanup_failed_attach_current_thread() { 1951 if (get_thread_profiler() != NULL) { 1952 get_thread_profiler()->disengage(); 1953 ResourceMark rm; 1954 get_thread_profiler()->print(get_thread_name()); 1955 } 1956 1957 if (active_handles() != NULL) { 1958 JNIHandleBlock* block = active_handles(); 1959 set_active_handles(NULL); 1960 JNIHandleBlock::release_block(block); 1961 } 1962 1963 if (free_handle_block() != NULL) { 1964 JNIHandleBlock* block = free_handle_block(); 1965 set_free_handle_block(NULL); 1966 JNIHandleBlock::release_block(block); 1967 } 1968 1969 // These have to be removed while this is still a valid thread. 1970 remove_stack_guard_pages(); 1971 1972 if (UseTLAB) { 1973 tlab().make_parsable(true); // retire TLAB, if any 1974 } 1975 1976#if INCLUDE_ALL_GCS 1977 if (UseG1GC) { 1978 flush_barrier_queues(); 1979 } 1980#endif // INCLUDE_ALL_GCS 1981 1982 Threads::remove(this); 1983 delete this; 1984} 1985 1986 1987 1988 1989JavaThread* JavaThread::active() { 1990 Thread* thread = ThreadLocalStorage::thread(); 1991 assert(thread != NULL, "just checking"); 1992 if (thread->is_Java_thread()) { 1993 return (JavaThread*) thread; 1994 } else { 1995 assert(thread->is_VM_thread(), "this must be a vm thread"); 1996 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1997 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1998 assert(ret->is_Java_thread(), "must be a Java thread"); 1999 return ret; 2000 } 2001} 2002 2003bool JavaThread::is_lock_owned(address adr) const { 2004 if (Thread::is_lock_owned(adr)) return true; 2005 2006 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2007 if (chunk->contains(adr)) return true; 2008 } 2009 2010 return false; 2011} 2012 2013 2014void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2015 chunk->set_next(monitor_chunks()); 2016 set_monitor_chunks(chunk); 2017} 2018 2019void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2020 guarantee(monitor_chunks() != NULL, "must be non empty"); 2021 if (monitor_chunks() == chunk) { 2022 set_monitor_chunks(chunk->next()); 2023 } else { 2024 MonitorChunk* prev = monitor_chunks(); 2025 while (prev->next() != chunk) prev = prev->next(); 2026 prev->set_next(chunk->next()); 2027 } 2028} 2029 2030// JVM support. 2031 2032// Note: this function shouldn't block if it's called in 2033// _thread_in_native_trans state (such as from 2034// check_special_condition_for_native_trans()). 2035void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2036 2037 if (has_last_Java_frame() && has_async_condition()) { 2038 // If we are at a polling page safepoint (not a poll return) 2039 // then we must defer async exception because live registers 2040 // will be clobbered by the exception path. Poll return is 2041 // ok because the call we a returning from already collides 2042 // with exception handling registers and so there is no issue. 2043 // (The exception handling path kills call result registers but 2044 // this is ok since the exception kills the result anyway). 2045 2046 if (is_at_poll_safepoint()) { 2047 // if the code we are returning to has deoptimized we must defer 2048 // the exception otherwise live registers get clobbered on the 2049 // exception path before deoptimization is able to retrieve them. 2050 // 2051 RegisterMap map(this, false); 2052 frame caller_fr = last_frame().sender(&map); 2053 assert(caller_fr.is_compiled_frame(), "what?"); 2054 if (caller_fr.is_deoptimized_frame()) { 2055 if (TraceExceptions) { 2056 ResourceMark rm; 2057 tty->print_cr("deferred async exception at compiled safepoint"); 2058 } 2059 return; 2060 } 2061 } 2062 } 2063 2064 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2065 if (condition == _no_async_condition) { 2066 // Conditions have changed since has_special_runtime_exit_condition() 2067 // was called: 2068 // - if we were here only because of an external suspend request, 2069 // then that was taken care of above (or cancelled) so we are done 2070 // - if we were here because of another async request, then it has 2071 // been cleared between the has_special_runtime_exit_condition() 2072 // and now so again we are done 2073 return; 2074 } 2075 2076 // Check for pending async. exception 2077 if (_pending_async_exception != NULL) { 2078 // Only overwrite an already pending exception, if it is not a threadDeath. 2079 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2080 2081 // We cannot call Exceptions::_throw(...) here because we cannot block 2082 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2083 2084 if (TraceExceptions) { 2085 ResourceMark rm; 2086 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2087 if (has_last_Java_frame() ) { 2088 frame f = last_frame(); 2089 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2090 } 2091 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2092 } 2093 _pending_async_exception = NULL; 2094 clear_has_async_exception(); 2095 } 2096 } 2097 2098 if (check_unsafe_error && 2099 condition == _async_unsafe_access_error && !has_pending_exception()) { 2100 condition = _no_async_condition; // done 2101 switch (thread_state()) { 2102 case _thread_in_vm: 2103 { 2104 JavaThread* THREAD = this; 2105 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2106 } 2107 case _thread_in_native: 2108 { 2109 ThreadInVMfromNative tiv(this); 2110 JavaThread* THREAD = this; 2111 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2112 } 2113 case _thread_in_Java: 2114 { 2115 ThreadInVMfromJava tiv(this); 2116 JavaThread* THREAD = this; 2117 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2118 } 2119 default: 2120 ShouldNotReachHere(); 2121 } 2122 } 2123 2124 assert(condition == _no_async_condition || has_pending_exception() || 2125 (!check_unsafe_error && condition == _async_unsafe_access_error), 2126 "must have handled the async condition, if no exception"); 2127} 2128 2129void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2130 // 2131 // Check for pending external suspend. Internal suspend requests do 2132 // not use handle_special_runtime_exit_condition(). 2133 // If JNIEnv proxies are allowed, don't self-suspend if the target 2134 // thread is not the current thread. In older versions of jdbx, jdbx 2135 // threads could call into the VM with another thread's JNIEnv so we 2136 // can be here operating on behalf of a suspended thread (4432884). 2137 bool do_self_suspend = is_external_suspend_with_lock(); 2138 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2139 // 2140 // Because thread is external suspended the safepoint code will count 2141 // thread as at a safepoint. This can be odd because we can be here 2142 // as _thread_in_Java which would normally transition to _thread_blocked 2143 // at a safepoint. We would like to mark the thread as _thread_blocked 2144 // before calling java_suspend_self like all other callers of it but 2145 // we must then observe proper safepoint protocol. (We can't leave 2146 // _thread_blocked with a safepoint in progress). However we can be 2147 // here as _thread_in_native_trans so we can't use a normal transition 2148 // constructor/destructor pair because they assert on that type of 2149 // transition. We could do something like: 2150 // 2151 // JavaThreadState state = thread_state(); 2152 // set_thread_state(_thread_in_vm); 2153 // { 2154 // ThreadBlockInVM tbivm(this); 2155 // java_suspend_self() 2156 // } 2157 // set_thread_state(_thread_in_vm_trans); 2158 // if (safepoint) block; 2159 // set_thread_state(state); 2160 // 2161 // but that is pretty messy. Instead we just go with the way the 2162 // code has worked before and note that this is the only path to 2163 // java_suspend_self that doesn't put the thread in _thread_blocked 2164 // mode. 2165 2166 frame_anchor()->make_walkable(this); 2167 java_suspend_self(); 2168 2169 // We might be here for reasons in addition to the self-suspend request 2170 // so check for other async requests. 2171 } 2172 2173 if (check_asyncs) { 2174 check_and_handle_async_exceptions(); 2175 } 2176} 2177 2178void JavaThread::send_thread_stop(oop java_throwable) { 2179 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2180 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2181 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2182 2183 // Do not throw asynchronous exceptions against the compiler thread 2184 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2185 if (is_Compiler_thread()) return; 2186 2187 { 2188 // Actually throw the Throwable against the target Thread - however 2189 // only if there is no thread death exception installed already. 2190 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2191 // If the topmost frame is a runtime stub, then we are calling into 2192 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2193 // must deoptimize the caller before continuing, as the compiled exception handler table 2194 // may not be valid 2195 if (has_last_Java_frame()) { 2196 frame f = last_frame(); 2197 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2198 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2199 RegisterMap reg_map(this, UseBiasedLocking); 2200 frame compiled_frame = f.sender(®_map); 2201 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2202 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2203 } 2204 } 2205 } 2206 2207 // Set async. pending exception in thread. 2208 set_pending_async_exception(java_throwable); 2209 2210 if (TraceExceptions) { 2211 ResourceMark rm; 2212 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2213 } 2214 // for AbortVMOnException flag 2215 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2216 } 2217 } 2218 2219 2220 // Interrupt thread so it will wake up from a potential wait() 2221 Thread::interrupt(this); 2222} 2223 2224// External suspension mechanism. 2225// 2226// Tell the VM to suspend a thread when ever it knows that it does not hold on 2227// to any VM_locks and it is at a transition 2228// Self-suspension will happen on the transition out of the vm. 2229// Catch "this" coming in from JNIEnv pointers when the thread has been freed 2230// 2231// Guarantees on return: 2232// + Target thread will not execute any new bytecode (that's why we need to 2233// force a safepoint) 2234// + Target thread will not enter any new monitors 2235// 2236void JavaThread::java_suspend() { 2237 { MutexLocker mu(Threads_lock); 2238 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2239 return; 2240 } 2241 } 2242 2243 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2244 if (!is_external_suspend()) { 2245 // a racing resume has cancelled us; bail out now 2246 return; 2247 } 2248 2249 // suspend is done 2250 uint32_t debug_bits = 0; 2251 // Warning: is_ext_suspend_completed() may temporarily drop the 2252 // SR_lock to allow the thread to reach a stable thread state if 2253 // it is currently in a transient thread state. 2254 if (is_ext_suspend_completed(false /* !called_by_wait */, 2255 SuspendRetryDelay, &debug_bits) ) { 2256 return; 2257 } 2258 } 2259 2260 VM_ForceSafepoint vm_suspend; 2261 VMThread::execute(&vm_suspend); 2262} 2263 2264// Part II of external suspension. 2265// A JavaThread self suspends when it detects a pending external suspend 2266// request. This is usually on transitions. It is also done in places 2267// where continuing to the next transition would surprise the caller, 2268// e.g., monitor entry. 2269// 2270// Returns the number of times that the thread self-suspended. 2271// 2272// Note: DO NOT call java_suspend_self() when you just want to block current 2273// thread. java_suspend_self() is the second stage of cooperative 2274// suspension for external suspend requests and should only be used 2275// to complete an external suspend request. 2276// 2277int JavaThread::java_suspend_self() { 2278 int ret = 0; 2279 2280 // we are in the process of exiting so don't suspend 2281 if (is_exiting()) { 2282 clear_external_suspend(); 2283 return ret; 2284 } 2285 2286 assert(_anchor.walkable() || 2287 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2288 "must have walkable stack"); 2289 2290 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2291 2292 assert(!this->is_ext_suspended(), 2293 "a thread trying to self-suspend should not already be suspended"); 2294 2295 if (this->is_suspend_equivalent()) { 2296 // If we are self-suspending as a result of the lifting of a 2297 // suspend equivalent condition, then the suspend_equivalent 2298 // flag is not cleared until we set the ext_suspended flag so 2299 // that wait_for_ext_suspend_completion() returns consistent 2300 // results. 2301 this->clear_suspend_equivalent(); 2302 } 2303 2304 // A racing resume may have cancelled us before we grabbed SR_lock 2305 // above. Or another external suspend request could be waiting for us 2306 // by the time we return from SR_lock()->wait(). The thread 2307 // that requested the suspension may already be trying to walk our 2308 // stack and if we return now, we can change the stack out from under 2309 // it. This would be a "bad thing (TM)" and cause the stack walker 2310 // to crash. We stay self-suspended until there are no more pending 2311 // external suspend requests. 2312 while (is_external_suspend()) { 2313 ret++; 2314 this->set_ext_suspended(); 2315 2316 // _ext_suspended flag is cleared by java_resume() 2317 while (is_ext_suspended()) { 2318 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2319 } 2320 } 2321 2322 return ret; 2323} 2324 2325#ifdef ASSERT 2326// verify the JavaThread has not yet been published in the Threads::list, and 2327// hence doesn't need protection from concurrent access at this stage 2328void JavaThread::verify_not_published() { 2329 if (!Threads_lock->owned_by_self()) { 2330 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2331 assert( !Threads::includes(this), 2332 "java thread shouldn't have been published yet!"); 2333 } 2334 else { 2335 assert( !Threads::includes(this), 2336 "java thread shouldn't have been published yet!"); 2337 } 2338} 2339#endif 2340 2341// Slow path when the native==>VM/Java barriers detect a safepoint is in 2342// progress or when _suspend_flags is non-zero. 2343// Current thread needs to self-suspend if there is a suspend request and/or 2344// block if a safepoint is in progress. 2345// Async exception ISN'T checked. 2346// Note only the ThreadInVMfromNative transition can call this function 2347// directly and when thread state is _thread_in_native_trans 2348void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2349 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2350 2351 JavaThread *curJT = JavaThread::current(); 2352 bool do_self_suspend = thread->is_external_suspend(); 2353 2354 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2355 2356 // If JNIEnv proxies are allowed, don't self-suspend if the target 2357 // thread is not the current thread. In older versions of jdbx, jdbx 2358 // threads could call into the VM with another thread's JNIEnv so we 2359 // can be here operating on behalf of a suspended thread (4432884). 2360 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2361 JavaThreadState state = thread->thread_state(); 2362 2363 // We mark this thread_blocked state as a suspend-equivalent so 2364 // that a caller to is_ext_suspend_completed() won't be confused. 2365 // The suspend-equivalent state is cleared by java_suspend_self(). 2366 thread->set_suspend_equivalent(); 2367 2368 // If the safepoint code sees the _thread_in_native_trans state, it will 2369 // wait until the thread changes to other thread state. There is no 2370 // guarantee on how soon we can obtain the SR_lock and complete the 2371 // self-suspend request. It would be a bad idea to let safepoint wait for 2372 // too long. Temporarily change the state to _thread_blocked to 2373 // let the VM thread know that this thread is ready for GC. The problem 2374 // of changing thread state is that safepoint could happen just after 2375 // java_suspend_self() returns after being resumed, and VM thread will 2376 // see the _thread_blocked state. We must check for safepoint 2377 // after restoring the state and make sure we won't leave while a safepoint 2378 // is in progress. 2379 thread->set_thread_state(_thread_blocked); 2380 thread->java_suspend_self(); 2381 thread->set_thread_state(state); 2382 // Make sure new state is seen by VM thread 2383 if (os::is_MP()) { 2384 if (UseMembar) { 2385 // Force a fence between the write above and read below 2386 OrderAccess::fence(); 2387 } else { 2388 // Must use this rather than serialization page in particular on Windows 2389 InterfaceSupport::serialize_memory(thread); 2390 } 2391 } 2392 } 2393 2394 if (SafepointSynchronize::do_call_back()) { 2395 // If we are safepointing, then block the caller which may not be 2396 // the same as the target thread (see above). 2397 SafepointSynchronize::block(curJT); 2398 } 2399 2400 if (thread->is_deopt_suspend()) { 2401 thread->clear_deopt_suspend(); 2402 RegisterMap map(thread, false); 2403 frame f = thread->last_frame(); 2404 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2405 f = f.sender(&map); 2406 } 2407 if (f.id() == thread->must_deopt_id()) { 2408 thread->clear_must_deopt_id(); 2409 f.deoptimize(thread); 2410 } else { 2411 fatal("missed deoptimization!"); 2412 } 2413 } 2414} 2415 2416// Slow path when the native==>VM/Java barriers detect a safepoint is in 2417// progress or when _suspend_flags is non-zero. 2418// Current thread needs to self-suspend if there is a suspend request and/or 2419// block if a safepoint is in progress. 2420// Also check for pending async exception (not including unsafe access error). 2421// Note only the native==>VM/Java barriers can call this function and when 2422// thread state is _thread_in_native_trans. 2423void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2424 check_safepoint_and_suspend_for_native_trans(thread); 2425 2426 if (thread->has_async_exception()) { 2427 // We are in _thread_in_native_trans state, don't handle unsafe 2428 // access error since that may block. 2429 thread->check_and_handle_async_exceptions(false); 2430 } 2431} 2432 2433// This is a variant of the normal 2434// check_special_condition_for_native_trans with slightly different 2435// semantics for use by critical native wrappers. It does all the 2436// normal checks but also performs the transition back into 2437// thread_in_Java state. This is required so that critical natives 2438// can potentially block and perform a GC if they are the last thread 2439// exiting the GC_locker. 2440void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2441 check_special_condition_for_native_trans(thread); 2442 2443 // Finish the transition 2444 thread->set_thread_state(_thread_in_Java); 2445 2446 if (thread->do_critical_native_unlock()) { 2447 ThreadInVMfromJavaNoAsyncException tiv(thread); 2448 GC_locker::unlock_critical(thread); 2449 thread->clear_critical_native_unlock(); 2450 } 2451} 2452 2453// We need to guarantee the Threads_lock here, since resumes are not 2454// allowed during safepoint synchronization 2455// Can only resume from an external suspension 2456void JavaThread::java_resume() { 2457 assert_locked_or_safepoint(Threads_lock); 2458 2459 // Sanity check: thread is gone, has started exiting or the thread 2460 // was not externally suspended. 2461 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2462 return; 2463 } 2464 2465 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2466 2467 clear_external_suspend(); 2468 2469 if (is_ext_suspended()) { 2470 clear_ext_suspended(); 2471 SR_lock()->notify_all(); 2472 } 2473} 2474 2475void JavaThread::create_stack_guard_pages() { 2476 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2477 address low_addr = stack_base() - stack_size(); 2478 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2479 2480 int allocate = os::allocate_stack_guard_pages(); 2481 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2482 2483 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2484 warning("Attempt to allocate stack guard pages failed."); 2485 return; 2486 } 2487 2488 if (os::guard_memory((char *) low_addr, len)) { 2489 _stack_guard_state = stack_guard_enabled; 2490 } else { 2491 warning("Attempt to protect stack guard pages failed."); 2492 if (os::uncommit_memory((char *) low_addr, len)) { 2493 warning("Attempt to deallocate stack guard pages failed."); 2494 } 2495 } 2496} 2497 2498void JavaThread::remove_stack_guard_pages() { 2499 assert(Thread::current() == this, "from different thread"); 2500 if (_stack_guard_state == stack_guard_unused) return; 2501 address low_addr = stack_base() - stack_size(); 2502 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2503 2504 if (os::allocate_stack_guard_pages()) { 2505 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2506 _stack_guard_state = stack_guard_unused; 2507 } else { 2508 warning("Attempt to deallocate stack guard pages failed."); 2509 } 2510 } else { 2511 if (_stack_guard_state == stack_guard_unused) return; 2512 if (os::unguard_memory((char *) low_addr, len)) { 2513 _stack_guard_state = stack_guard_unused; 2514 } else { 2515 warning("Attempt to unprotect stack guard pages failed."); 2516 } 2517 } 2518} 2519 2520void JavaThread::enable_stack_yellow_zone() { 2521 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2522 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2523 2524 // The base notation is from the stacks point of view, growing downward. 2525 // We need to adjust it to work correctly with guard_memory() 2526 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2527 2528 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2529 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2530 2531 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2532 _stack_guard_state = stack_guard_enabled; 2533 } else { 2534 warning("Attempt to guard stack yellow zone failed."); 2535 } 2536 enable_register_stack_guard(); 2537} 2538 2539void JavaThread::disable_stack_yellow_zone() { 2540 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2541 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2542 2543 // Simply return if called for a thread that does not use guard pages. 2544 if (_stack_guard_state == stack_guard_unused) return; 2545 2546 // The base notation is from the stacks point of view, growing downward. 2547 // We need to adjust it to work correctly with guard_memory() 2548 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2549 2550 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2551 _stack_guard_state = stack_guard_yellow_disabled; 2552 } else { 2553 warning("Attempt to unguard stack yellow zone failed."); 2554 } 2555 disable_register_stack_guard(); 2556} 2557 2558void JavaThread::enable_stack_red_zone() { 2559 // The base notation is from the stacks point of view, growing downward. 2560 // We need to adjust it to work correctly with guard_memory() 2561 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2562 address base = stack_red_zone_base() - stack_red_zone_size(); 2563 2564 guarantee(base < stack_base(),"Error calculating stack red zone"); 2565 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2566 2567 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2568 warning("Attempt to guard stack red zone failed."); 2569 } 2570} 2571 2572void JavaThread::disable_stack_red_zone() { 2573 // The base notation is from the stacks point of view, growing downward. 2574 // We need to adjust it to work correctly with guard_memory() 2575 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2576 address base = stack_red_zone_base() - stack_red_zone_size(); 2577 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2578 warning("Attempt to unguard stack red zone failed."); 2579 } 2580} 2581 2582void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2583 // ignore is there is no stack 2584 if (!has_last_Java_frame()) return; 2585 // traverse the stack frames. Starts from top frame. 2586 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2587 frame* fr = fst.current(); 2588 f(fr, fst.register_map()); 2589 } 2590} 2591 2592 2593#ifndef PRODUCT 2594// Deoptimization 2595// Function for testing deoptimization 2596void JavaThread::deoptimize() { 2597 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2598 StackFrameStream fst(this, UseBiasedLocking); 2599 bool deopt = false; // Dump stack only if a deopt actually happens. 2600 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2601 // Iterate over all frames in the thread and deoptimize 2602 for(; !fst.is_done(); fst.next()) { 2603 if(fst.current()->can_be_deoptimized()) { 2604 2605 if (only_at) { 2606 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2607 // consists of comma or carriage return separated numbers so 2608 // search for the current bci in that string. 2609 address pc = fst.current()->pc(); 2610 nmethod* nm = (nmethod*) fst.current()->cb(); 2611 ScopeDesc* sd = nm->scope_desc_at( pc); 2612 char buffer[8]; 2613 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2614 size_t len = strlen(buffer); 2615 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2616 while (found != NULL) { 2617 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2618 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2619 // Check that the bci found is bracketed by terminators. 2620 break; 2621 } 2622 found = strstr(found + 1, buffer); 2623 } 2624 if (!found) { 2625 continue; 2626 } 2627 } 2628 2629 if (DebugDeoptimization && !deopt) { 2630 deopt = true; // One-time only print before deopt 2631 tty->print_cr("[BEFORE Deoptimization]"); 2632 trace_frames(); 2633 trace_stack(); 2634 } 2635 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2636 } 2637 } 2638 2639 if (DebugDeoptimization && deopt) { 2640 tty->print_cr("[AFTER Deoptimization]"); 2641 trace_frames(); 2642 } 2643} 2644 2645 2646// Make zombies 2647void JavaThread::make_zombies() { 2648 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2649 if (fst.current()->can_be_deoptimized()) { 2650 // it is a Java nmethod 2651 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2652 nm->make_not_entrant(); 2653 } 2654 } 2655} 2656#endif // PRODUCT 2657 2658 2659void JavaThread::deoptimized_wrt_marked_nmethods() { 2660 if (!has_last_Java_frame()) return; 2661 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2662 StackFrameStream fst(this, UseBiasedLocking); 2663 for(; !fst.is_done(); fst.next()) { 2664 if (fst.current()->should_be_deoptimized()) { 2665 if (LogCompilation && xtty != NULL) { 2666 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2667 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2668 this->name(), nm != NULL ? nm->compile_id() : -1); 2669 } 2670 2671 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2672 } 2673 } 2674} 2675 2676 2677// GC support 2678static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2679 2680void JavaThread::gc_epilogue() { 2681 frames_do(frame_gc_epilogue); 2682} 2683 2684 2685static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2686 2687void JavaThread::gc_prologue() { 2688 frames_do(frame_gc_prologue); 2689} 2690 2691// If the caller is a NamedThread, then remember, in the current scope, 2692// the given JavaThread in its _processed_thread field. 2693class RememberProcessedThread: public StackObj { 2694 NamedThread* _cur_thr; 2695public: 2696 RememberProcessedThread(JavaThread* jthr) { 2697 Thread* thread = Thread::current(); 2698 if (thread->is_Named_thread()) { 2699 _cur_thr = (NamedThread *)thread; 2700 _cur_thr->set_processed_thread(jthr); 2701 } else { 2702 _cur_thr = NULL; 2703 } 2704 } 2705 2706 ~RememberProcessedThread() { 2707 if (_cur_thr) { 2708 _cur_thr->set_processed_thread(NULL); 2709 } 2710 } 2711}; 2712 2713void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2714 // Verify that the deferred card marks have been flushed. 2715 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2716 2717 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2718 // since there may be more than one thread using each ThreadProfiler. 2719 2720 // Traverse the GCHandles 2721 Thread::oops_do(f, cld_f, cf); 2722 2723 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2724 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2725 2726 if (has_last_Java_frame()) { 2727 // Record JavaThread to GC thread 2728 RememberProcessedThread rpt(this); 2729 2730 // Traverse the privileged stack 2731 if (_privileged_stack_top != NULL) { 2732 _privileged_stack_top->oops_do(f); 2733 } 2734 2735 // traverse the registered growable array 2736 if (_array_for_gc != NULL) { 2737 for (int index = 0; index < _array_for_gc->length(); index++) { 2738 f->do_oop(_array_for_gc->adr_at(index)); 2739 } 2740 } 2741 2742 // Traverse the monitor chunks 2743 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2744 chunk->oops_do(f); 2745 } 2746 2747 // Traverse the execution stack 2748 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2749 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2750 } 2751 } 2752 2753 // callee_target is never live across a gc point so NULL it here should 2754 // it still contain a methdOop. 2755 2756 set_callee_target(NULL); 2757 2758 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2759 // If we have deferred set_locals there might be oops waiting to be 2760 // written 2761 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2762 if (list != NULL) { 2763 for (int i = 0; i < list->length(); i++) { 2764 list->at(i)->oops_do(f); 2765 } 2766 } 2767 2768 // Traverse instance variables at the end since the GC may be moving things 2769 // around using this function 2770 f->do_oop((oop*) &_threadObj); 2771 f->do_oop((oop*) &_vm_result); 2772 f->do_oop((oop*) &_exception_oop); 2773 f->do_oop((oop*) &_pending_async_exception); 2774 2775 if (jvmti_thread_state() != NULL) { 2776 jvmti_thread_state()->oops_do(f); 2777 } 2778} 2779 2780void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2781 Thread::nmethods_do(cf); // (super method is a no-op) 2782 2783 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2784 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2785 2786 if (has_last_Java_frame()) { 2787 // Traverse the execution stack 2788 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2789 fst.current()->nmethods_do(cf); 2790 } 2791 } 2792} 2793 2794void JavaThread::metadata_do(void f(Metadata*)) { 2795 Thread::metadata_do(f); 2796 if (has_last_Java_frame()) { 2797 // Traverse the execution stack to call f() on the methods in the stack 2798 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2799 fst.current()->metadata_do(f); 2800 } 2801 } else if (is_Compiler_thread()) { 2802 // need to walk ciMetadata in current compile tasks to keep alive. 2803 CompilerThread* ct = (CompilerThread*)this; 2804 if (ct->env() != NULL) { 2805 ct->env()->metadata_do(f); 2806 } 2807 } 2808} 2809 2810// Printing 2811const char* _get_thread_state_name(JavaThreadState _thread_state) { 2812 switch (_thread_state) { 2813 case _thread_uninitialized: return "_thread_uninitialized"; 2814 case _thread_new: return "_thread_new"; 2815 case _thread_new_trans: return "_thread_new_trans"; 2816 case _thread_in_native: return "_thread_in_native"; 2817 case _thread_in_native_trans: return "_thread_in_native_trans"; 2818 case _thread_in_vm: return "_thread_in_vm"; 2819 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2820 case _thread_in_Java: return "_thread_in_Java"; 2821 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2822 case _thread_blocked: return "_thread_blocked"; 2823 case _thread_blocked_trans: return "_thread_blocked_trans"; 2824 default: return "unknown thread state"; 2825 } 2826} 2827 2828#ifndef PRODUCT 2829void JavaThread::print_thread_state_on(outputStream *st) const { 2830 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2831}; 2832void JavaThread::print_thread_state() const { 2833 print_thread_state_on(tty); 2834}; 2835#endif // PRODUCT 2836 2837// Called by Threads::print() for VM_PrintThreads operation 2838void JavaThread::print_on(outputStream *st) const { 2839 st->print("\"%s\" ", get_thread_name()); 2840 oop thread_oop = threadObj(); 2841 if (thread_oop != NULL) { 2842 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2843 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2844 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2845 } 2846 Thread::print_on(st); 2847 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2848 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2849 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2850 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2851 } 2852#ifndef PRODUCT 2853 print_thread_state_on(st); 2854 _safepoint_state->print_on(st); 2855#endif // PRODUCT 2856} 2857 2858// Called by fatal error handler. The difference between this and 2859// JavaThread::print() is that we can't grab lock or allocate memory. 2860void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2861 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2862 oop thread_obj = threadObj(); 2863 if (thread_obj != NULL) { 2864 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2865 } 2866 st->print(" ["); 2867 st->print("%s", _get_thread_state_name(_thread_state)); 2868 if (osthread()) { 2869 st->print(", id=%d", osthread()->thread_id()); 2870 } 2871 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2872 _stack_base - _stack_size, _stack_base); 2873 st->print("]"); 2874 return; 2875} 2876 2877// Verification 2878 2879static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2880 2881void JavaThread::verify() { 2882 // Verify oops in the thread. 2883 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2884 2885 // Verify the stack frames. 2886 frames_do(frame_verify); 2887} 2888 2889// CR 6300358 (sub-CR 2137150) 2890// Most callers of this method assume that it can't return NULL but a 2891// thread may not have a name whilst it is in the process of attaching to 2892// the VM - see CR 6412693, and there are places where a JavaThread can be 2893// seen prior to having it's threadObj set (eg JNI attaching threads and 2894// if vm exit occurs during initialization). These cases can all be accounted 2895// for such that this method never returns NULL. 2896const char* JavaThread::get_thread_name() const { 2897#ifdef ASSERT 2898 // early safepoints can hit while current thread does not yet have TLS 2899 if (!SafepointSynchronize::is_at_safepoint()) { 2900 Thread *cur = Thread::current(); 2901 if (!(cur->is_Java_thread() && cur == this)) { 2902 // Current JavaThreads are allowed to get their own name without 2903 // the Threads_lock. 2904 assert_locked_or_safepoint(Threads_lock); 2905 } 2906 } 2907#endif // ASSERT 2908 return get_thread_name_string(); 2909} 2910 2911// Returns a non-NULL representation of this thread's name, or a suitable 2912// descriptive string if there is no set name 2913const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2914 const char* name_str; 2915 oop thread_obj = threadObj(); 2916 if (thread_obj != NULL) { 2917 typeArrayOop name = java_lang_Thread::name(thread_obj); 2918 if (name != NULL) { 2919 if (buf == NULL) { 2920 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2921 } 2922 else { 2923 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2924 } 2925 } 2926 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2927 name_str = "<no-name - thread is attaching>"; 2928 } 2929 else { 2930 name_str = Thread::name(); 2931 } 2932 } 2933 else { 2934 name_str = Thread::name(); 2935 } 2936 assert(name_str != NULL, "unexpected NULL thread name"); 2937 return name_str; 2938} 2939 2940 2941const char* JavaThread::get_threadgroup_name() const { 2942 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2943 oop thread_obj = threadObj(); 2944 if (thread_obj != NULL) { 2945 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2946 if (thread_group != NULL) { 2947 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2948 // ThreadGroup.name can be null 2949 if (name != NULL) { 2950 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2951 return str; 2952 } 2953 } 2954 } 2955 return NULL; 2956} 2957 2958const char* JavaThread::get_parent_name() const { 2959 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2960 oop thread_obj = threadObj(); 2961 if (thread_obj != NULL) { 2962 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2963 if (thread_group != NULL) { 2964 oop parent = java_lang_ThreadGroup::parent(thread_group); 2965 if (parent != NULL) { 2966 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2967 // ThreadGroup.name can be null 2968 if (name != NULL) { 2969 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2970 return str; 2971 } 2972 } 2973 } 2974 } 2975 return NULL; 2976} 2977 2978ThreadPriority JavaThread::java_priority() const { 2979 oop thr_oop = threadObj(); 2980 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2981 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2982 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2983 return priority; 2984} 2985 2986void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2987 2988 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2989 // Link Java Thread object <-> C++ Thread 2990 2991 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2992 // and put it into a new Handle. The Handle "thread_oop" can then 2993 // be used to pass the C++ thread object to other methods. 2994 2995 // Set the Java level thread object (jthread) field of the 2996 // new thread (a JavaThread *) to C++ thread object using the 2997 // "thread_oop" handle. 2998 2999 // Set the thread field (a JavaThread *) of the 3000 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3001 3002 Handle thread_oop(Thread::current(), 3003 JNIHandles::resolve_non_null(jni_thread)); 3004 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3005 "must be initialized"); 3006 set_threadObj(thread_oop()); 3007 java_lang_Thread::set_thread(thread_oop(), this); 3008 3009 if (prio == NoPriority) { 3010 prio = java_lang_Thread::priority(thread_oop()); 3011 assert(prio != NoPriority, "A valid priority should be present"); 3012 } 3013 3014 // Push the Java priority down to the native thread; needs Threads_lock 3015 Thread::set_priority(this, prio); 3016 3017 // Add the new thread to the Threads list and set it in motion. 3018 // We must have threads lock in order to call Threads::add. 3019 // It is crucial that we do not block before the thread is 3020 // added to the Threads list for if a GC happens, then the java_thread oop 3021 // will not be visited by GC. 3022 Threads::add(this); 3023} 3024 3025oop JavaThread::current_park_blocker() { 3026 // Support for JSR-166 locks 3027 oop thread_oop = threadObj(); 3028 if (thread_oop != NULL && 3029 JDK_Version::current().supports_thread_park_blocker()) { 3030 return java_lang_Thread::park_blocker(thread_oop); 3031 } 3032 return NULL; 3033} 3034 3035 3036void JavaThread::print_stack_on(outputStream* st) { 3037 if (!has_last_Java_frame()) return; 3038 ResourceMark rm; 3039 HandleMark hm; 3040 3041 RegisterMap reg_map(this); 3042 vframe* start_vf = last_java_vframe(®_map); 3043 int count = 0; 3044 for (vframe* f = start_vf; f; f = f->sender() ) { 3045 if (f->is_java_frame()) { 3046 javaVFrame* jvf = javaVFrame::cast(f); 3047 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3048 3049 // Print out lock information 3050 if (JavaMonitorsInStackTrace) { 3051 jvf->print_lock_info_on(st, count); 3052 } 3053 } else { 3054 // Ignore non-Java frames 3055 } 3056 3057 // Bail-out case for too deep stacks 3058 count++; 3059 if (MaxJavaStackTraceDepth == count) return; 3060 } 3061} 3062 3063 3064// JVMTI PopFrame support 3065void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3066 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3067 if (in_bytes(size_in_bytes) != 0) { 3068 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3069 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3070 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3071 } 3072} 3073 3074void* JavaThread::popframe_preserved_args() { 3075 return _popframe_preserved_args; 3076} 3077 3078ByteSize JavaThread::popframe_preserved_args_size() { 3079 return in_ByteSize(_popframe_preserved_args_size); 3080} 3081 3082WordSize JavaThread::popframe_preserved_args_size_in_words() { 3083 int sz = in_bytes(popframe_preserved_args_size()); 3084 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3085 return in_WordSize(sz / wordSize); 3086} 3087 3088void JavaThread::popframe_free_preserved_args() { 3089 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3090 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3091 _popframe_preserved_args = NULL; 3092 _popframe_preserved_args_size = 0; 3093} 3094 3095#ifndef PRODUCT 3096 3097void JavaThread::trace_frames() { 3098 tty->print_cr("[Describe stack]"); 3099 int frame_no = 1; 3100 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3101 tty->print(" %d. ", frame_no++); 3102 fst.current()->print_value_on(tty,this); 3103 tty->cr(); 3104 } 3105} 3106 3107class PrintAndVerifyOopClosure: public OopClosure { 3108 protected: 3109 template <class T> inline void do_oop_work(T* p) { 3110 oop obj = oopDesc::load_decode_heap_oop(p); 3111 if (obj == NULL) return; 3112 tty->print(INTPTR_FORMAT ": ", p); 3113 if (obj->is_oop_or_null()) { 3114 if (obj->is_objArray()) { 3115 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3116 } else { 3117 obj->print(); 3118 } 3119 } else { 3120 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3121 } 3122 tty->cr(); 3123 } 3124 public: 3125 virtual void do_oop(oop* p) { do_oop_work(p); } 3126 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3127}; 3128 3129 3130static void oops_print(frame* f, const RegisterMap *map) { 3131 PrintAndVerifyOopClosure print; 3132 f->print_value(); 3133 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3134} 3135 3136// Print our all the locations that contain oops and whether they are 3137// valid or not. This useful when trying to find the oldest frame 3138// where an oop has gone bad since the frame walk is from youngest to 3139// oldest. 3140void JavaThread::trace_oops() { 3141 tty->print_cr("[Trace oops]"); 3142 frames_do(oops_print); 3143} 3144 3145 3146#ifdef ASSERT 3147// Print or validate the layout of stack frames 3148void JavaThread::print_frame_layout(int depth, bool validate_only) { 3149 ResourceMark rm; 3150 PRESERVE_EXCEPTION_MARK; 3151 FrameValues values; 3152 int frame_no = 0; 3153 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3154 fst.current()->describe(values, ++frame_no); 3155 if (depth == frame_no) break; 3156 } 3157 if (validate_only) { 3158 values.validate(); 3159 } else { 3160 tty->print_cr("[Describe stack layout]"); 3161 values.print(this); 3162 } 3163} 3164#endif 3165 3166void JavaThread::trace_stack_from(vframe* start_vf) { 3167 ResourceMark rm; 3168 int vframe_no = 1; 3169 for (vframe* f = start_vf; f; f = f->sender() ) { 3170 if (f->is_java_frame()) { 3171 javaVFrame::cast(f)->print_activation(vframe_no++); 3172 } else { 3173 f->print(); 3174 } 3175 if (vframe_no > StackPrintLimit) { 3176 tty->print_cr("...<more frames>..."); 3177 return; 3178 } 3179 } 3180} 3181 3182 3183void JavaThread::trace_stack() { 3184 if (!has_last_Java_frame()) return; 3185 ResourceMark rm; 3186 HandleMark hm; 3187 RegisterMap reg_map(this); 3188 trace_stack_from(last_java_vframe(®_map)); 3189} 3190 3191 3192#endif // PRODUCT 3193 3194 3195javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3196 assert(reg_map != NULL, "a map must be given"); 3197 frame f = last_frame(); 3198 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3199 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3200 } 3201 return NULL; 3202} 3203 3204 3205Klass* JavaThread::security_get_caller_class(int depth) { 3206 vframeStream vfst(this); 3207 vfst.security_get_caller_frame(depth); 3208 if (!vfst.at_end()) { 3209 return vfst.method()->method_holder(); 3210 } 3211 return NULL; 3212} 3213 3214static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3215 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3216 CompileBroker::compiler_thread_loop(); 3217} 3218 3219// Create a CompilerThread 3220CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3221: JavaThread(&compiler_thread_entry) { 3222 _env = NULL; 3223 _log = NULL; 3224 _task = NULL; 3225 _queue = queue; 3226 _counters = counters; 3227 _buffer_blob = NULL; 3228 _scanned_nmethod = NULL; 3229 _compiler = NULL; 3230 3231#ifndef PRODUCT 3232 _ideal_graph_printer = NULL; 3233#endif 3234} 3235 3236void CompilerThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3237 JavaThread::oops_do(f, cld_f, cf); 3238 if (_scanned_nmethod != NULL && cf != NULL) { 3239 // Safepoints can occur when the sweeper is scanning an nmethod so 3240 // process it here to make sure it isn't unloaded in the middle of 3241 // a scan. 3242 cf->do_code_blob(_scanned_nmethod); 3243 } 3244} 3245 3246 3247// ======= Threads ======== 3248 3249// The Threads class links together all active threads, and provides 3250// operations over all threads. It is protected by its own Mutex 3251// lock, which is also used in other contexts to protect thread 3252// operations from having the thread being operated on from exiting 3253// and going away unexpectedly (e.g., safepoint synchronization) 3254 3255JavaThread* Threads::_thread_list = NULL; 3256int Threads::_number_of_threads = 0; 3257int Threads::_number_of_non_daemon_threads = 0; 3258int Threads::_return_code = 0; 3259size_t JavaThread::_stack_size_at_create = 0; 3260#ifdef ASSERT 3261bool Threads::_vm_complete = false; 3262#endif 3263 3264// All JavaThreads 3265#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3266 3267// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3268void Threads::threads_do(ThreadClosure* tc) { 3269 assert_locked_or_safepoint(Threads_lock); 3270 // ALL_JAVA_THREADS iterates through all JavaThreads 3271 ALL_JAVA_THREADS(p) { 3272 tc->do_thread(p); 3273 } 3274 // Someday we could have a table or list of all non-JavaThreads. 3275 // For now, just manually iterate through them. 3276 tc->do_thread(VMThread::vm_thread()); 3277 Universe::heap()->gc_threads_do(tc); 3278 WatcherThread *wt = WatcherThread::watcher_thread(); 3279 // Strictly speaking, the following NULL check isn't sufficient to make sure 3280 // the data for WatcherThread is still valid upon being examined. However, 3281 // considering that WatchThread terminates when the VM is on the way to 3282 // exit at safepoint, the chance of the above is extremely small. The right 3283 // way to prevent termination of WatcherThread would be to acquire 3284 // Terminator_lock, but we can't do that without violating the lock rank 3285 // checking in some cases. 3286 if (wt != NULL) 3287 tc->do_thread(wt); 3288 3289 // If CompilerThreads ever become non-JavaThreads, add them here 3290} 3291 3292 3293void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3294 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3295 3296 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3297 create_vm_init_libraries(); 3298 } 3299 3300 initialize_class(vmSymbols::java_lang_String(), CHECK); 3301 3302 // Initialize java_lang.System (needed before creating the thread) 3303 initialize_class(vmSymbols::java_lang_System(), CHECK); 3304 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3305 Handle thread_group = create_initial_thread_group(CHECK); 3306 Universe::set_main_thread_group(thread_group()); 3307 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3308 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3309 main_thread->set_threadObj(thread_object); 3310 // Set thread status to running since main thread has 3311 // been started and running. 3312 java_lang_Thread::set_thread_status(thread_object, 3313 java_lang_Thread::RUNNABLE); 3314 3315 // The VM creates & returns objects of this class. Make sure it's initialized. 3316 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3317 3318 // The VM preresolves methods to these classes. Make sure that they get initialized 3319 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3320 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3321 call_initializeSystemClass(CHECK); 3322 3323 // get the Java runtime name after java.lang.System is initialized 3324 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3325 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3326 3327 // an instance of OutOfMemory exception has been allocated earlier 3328 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3329 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3330 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3331 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3332 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3333 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3334 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3335 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3336} 3337 3338void Threads::initialize_jsr292_core_classes(TRAPS) { 3339 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3340 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3341 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3342} 3343 3344jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3345 3346 extern void JDK_Version_init(); 3347 3348 // Check version 3349 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3350 3351 // Initialize the output stream module 3352 ostream_init(); 3353 3354 // Process java launcher properties. 3355 Arguments::process_sun_java_launcher_properties(args); 3356 3357 // Initialize the os module before using TLS 3358 os::init(); 3359 3360 // Initialize system properties. 3361 Arguments::init_system_properties(); 3362 3363 // So that JDK version can be used as a discriminator when parsing arguments 3364 JDK_Version_init(); 3365 3366 // Update/Initialize System properties after JDK version number is known 3367 Arguments::init_version_specific_system_properties(); 3368 3369 // Parse arguments 3370 jint parse_result = Arguments::parse(args); 3371 if (parse_result != JNI_OK) return parse_result; 3372 3373 os::init_before_ergo(); 3374 3375 jint ergo_result = Arguments::apply_ergo(); 3376 if (ergo_result != JNI_OK) return ergo_result; 3377 3378 if (PauseAtStartup) { 3379 os::pause(); 3380 } 3381 3382 HOTSPOT_VM_INIT_BEGIN(); 3383 3384 // Record VM creation timing statistics 3385 TraceVmCreationTime create_vm_timer; 3386 create_vm_timer.start(); 3387 3388 // Timing (must come after argument parsing) 3389 TraceTime timer("Create VM", TraceStartupTime); 3390 3391 // Initialize the os module after parsing the args 3392 jint os_init_2_result = os::init_2(); 3393 if (os_init_2_result != JNI_OK) return os_init_2_result; 3394 3395 jint adjust_after_os_result = Arguments::adjust_after_os(); 3396 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3397 3398 // initialize TLS 3399 ThreadLocalStorage::init(); 3400 3401 // Bootstrap native memory tracking, so it can start recording memory 3402 // activities before worker thread is started. This is the first phase 3403 // of bootstrapping, VM is currently running in single-thread mode. 3404 MemTracker::bootstrap_single_thread(); 3405 3406 // Initialize output stream logging 3407 ostream_init_log(); 3408 3409 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3410 // Must be before create_vm_init_agents() 3411 if (Arguments::init_libraries_at_startup()) { 3412 convert_vm_init_libraries_to_agents(); 3413 } 3414 3415 // Launch -agentlib/-agentpath and converted -Xrun agents 3416 if (Arguments::init_agents_at_startup()) { 3417 create_vm_init_agents(); 3418 } 3419 3420 // Initialize Threads state 3421 _thread_list = NULL; 3422 _number_of_threads = 0; 3423 _number_of_non_daemon_threads = 0; 3424 3425 // Initialize global data structures and create system classes in heap 3426 vm_init_globals(); 3427 3428 // Attach the main thread to this os thread 3429 JavaThread* main_thread = new JavaThread(); 3430 main_thread->set_thread_state(_thread_in_vm); 3431 // must do this before set_active_handles and initialize_thread_local_storage 3432 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3433 // change the stack size recorded here to one based on the java thread 3434 // stacksize. This adjusted size is what is used to figure the placement 3435 // of the guard pages. 3436 main_thread->record_stack_base_and_size(); 3437 main_thread->initialize_thread_local_storage(); 3438 3439 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3440 3441 if (!main_thread->set_as_starting_thread()) { 3442 vm_shutdown_during_initialization( 3443 "Failed necessary internal allocation. Out of swap space"); 3444 delete main_thread; 3445 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3446 return JNI_ENOMEM; 3447 } 3448 3449 // Enable guard page *after* os::create_main_thread(), otherwise it would 3450 // crash Linux VM, see notes in os_linux.cpp. 3451 main_thread->create_stack_guard_pages(); 3452 3453 // Initialize Java-Level synchronization subsystem 3454 ObjectMonitor::Initialize() ; 3455 3456 // Second phase of bootstrapping, VM is about entering multi-thread mode 3457 MemTracker::bootstrap_multi_thread(); 3458 3459 // Initialize global modules 3460 jint status = init_globals(); 3461 if (status != JNI_OK) { 3462 delete main_thread; 3463 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3464 return status; 3465 } 3466 3467 // Should be done after the heap is fully created 3468 main_thread->cache_global_variables(); 3469 3470 HandleMark hm; 3471 3472 { MutexLocker mu(Threads_lock); 3473 Threads::add(main_thread); 3474 } 3475 3476 // Any JVMTI raw monitors entered in onload will transition into 3477 // real raw monitor. VM is setup enough here for raw monitor enter. 3478 JvmtiExport::transition_pending_onload_raw_monitors(); 3479 3480 // Fully start NMT 3481 MemTracker::start(); 3482 3483 // Create the VMThread 3484 { TraceTime timer("Start VMThread", TraceStartupTime); 3485 VMThread::create(); 3486 Thread* vmthread = VMThread::vm_thread(); 3487 3488 if (!os::create_thread(vmthread, os::vm_thread)) 3489 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3490 3491 // Wait for the VM thread to become ready, and VMThread::run to initialize 3492 // Monitors can have spurious returns, must always check another state flag 3493 { 3494 MutexLocker ml(Notify_lock); 3495 os::start_thread(vmthread); 3496 while (vmthread->active_handles() == NULL) { 3497 Notify_lock->wait(); 3498 } 3499 } 3500 } 3501 3502 assert (Universe::is_fully_initialized(), "not initialized"); 3503 if (VerifyDuringStartup) { 3504 // Make sure we're starting with a clean slate. 3505 VM_Verify verify_op; 3506 VMThread::execute(&verify_op); 3507 } 3508 3509 Thread* THREAD = Thread::current(); 3510 3511 // At this point, the Universe is initialized, but we have not executed 3512 // any byte code. Now is a good time (the only time) to dump out the 3513 // internal state of the JVM for sharing. 3514 if (DumpSharedSpaces) { 3515 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3516 ShouldNotReachHere(); 3517 } 3518 3519 // Always call even when there are not JVMTI environments yet, since environments 3520 // may be attached late and JVMTI must track phases of VM execution 3521 JvmtiExport::enter_start_phase(); 3522 3523 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3524 JvmtiExport::post_vm_start(); 3525 3526 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3527 3528 // We need this for ClassDataSharing - the initial vm.info property is set 3529 // with the default value of CDS "sharing" which may be reset through 3530 // command line options. 3531 reset_vm_info_property(CHECK_JNI_ERR); 3532 3533 quicken_jni_functions(); 3534 3535 // Must be run after init_ft which initializes ft_enabled 3536 if (TRACE_INITIALIZE() != JNI_OK) { 3537 vm_exit_during_initialization("Failed to initialize tracing backend"); 3538 } 3539 3540 // Set flag that basic initialization has completed. Used by exceptions and various 3541 // debug stuff, that does not work until all basic classes have been initialized. 3542 set_init_completed(); 3543 3544 HOTSPOT_VM_INIT_END(); 3545 3546 // record VM initialization completion time 3547#if INCLUDE_MANAGEMENT 3548 Management::record_vm_init_completed(); 3549#endif // INCLUDE_MANAGEMENT 3550 3551 // Compute system loader. Note that this has to occur after set_init_completed, since 3552 // valid exceptions may be thrown in the process. 3553 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3554 // set_init_completed has just been called, causing exceptions not to be shortcut 3555 // anymore. We call vm_exit_during_initialization directly instead. 3556 SystemDictionary::compute_java_system_loader(CHECK_JNI_ERR); 3557 3558#if INCLUDE_ALL_GCS 3559 // Support for ConcurrentMarkSweep. This should be cleaned up 3560 // and better encapsulated. The ugly nested if test would go away 3561 // once things are properly refactored. XXX YSR 3562 if (UseConcMarkSweepGC || UseG1GC) { 3563 if (UseConcMarkSweepGC) { 3564 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3565 } else { 3566 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3567 } 3568 } 3569#endif // INCLUDE_ALL_GCS 3570 3571 // Always call even when there are not JVMTI environments yet, since environments 3572 // may be attached late and JVMTI must track phases of VM execution 3573 JvmtiExport::enter_live_phase(); 3574 3575 // Signal Dispatcher needs to be started before VMInit event is posted 3576 os::signal_init(); 3577 3578 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3579 if (!DisableAttachMechanism) { 3580 AttachListener::vm_start(); 3581 if (StartAttachListener || AttachListener::init_at_startup()) { 3582 AttachListener::init(); 3583 } 3584 } 3585 3586 // Launch -Xrun agents 3587 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3588 // back-end can launch with -Xdebug -Xrunjdwp. 3589 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3590 create_vm_init_libraries(); 3591 } 3592 3593 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3594 JvmtiExport::post_vm_initialized(); 3595 3596 if (TRACE_START() != JNI_OK) { 3597 vm_exit_during_initialization("Failed to start tracing backend."); 3598 } 3599 3600 if (CleanChunkPoolAsync) { 3601 Chunk::start_chunk_pool_cleaner_task(); 3602 } 3603 3604 // initialize compiler(s) 3605#if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3606 CompileBroker::compilation_init(); 3607#endif 3608 3609 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3610 // It is done after compilers are initialized, because otherwise compilations of 3611 // signature polymorphic MH intrinsics can be missed 3612 // (see SystemDictionary::find_method_handle_intrinsic). 3613 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3614 3615#if INCLUDE_MANAGEMENT 3616 Management::initialize(THREAD); 3617 3618 if (HAS_PENDING_EXCEPTION) { 3619 // management agent fails to start possibly due to 3620 // configuration problem and is responsible for printing 3621 // stack trace if appropriate. Simply exit VM. 3622 vm_exit(1); 3623 } 3624#endif // INCLUDE_MANAGEMENT 3625 3626 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3627 if (MemProfiling) MemProfiler::engage(); 3628 StatSampler::engage(); 3629 if (CheckJNICalls) JniPeriodicChecker::engage(); 3630 3631 BiasedLocking::init(); 3632 3633#if INCLUDE_RTM_OPT 3634 RTMLockingCounters::init(); 3635#endif 3636 3637 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3638 call_postVMInitHook(THREAD); 3639 // The Java side of PostVMInitHook.run must deal with all 3640 // exceptions and provide means of diagnosis. 3641 if (HAS_PENDING_EXCEPTION) { 3642 CLEAR_PENDING_EXCEPTION; 3643 } 3644 } 3645 3646 { 3647 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3648 // Make sure the watcher thread can be started by WatcherThread::start() 3649 // or by dynamic enrollment. 3650 WatcherThread::make_startable(); 3651 // Start up the WatcherThread if there are any periodic tasks 3652 // NOTE: All PeriodicTasks should be registered by now. If they 3653 // aren't, late joiners might appear to start slowly (we might 3654 // take a while to process their first tick). 3655 if (PeriodicTask::num_tasks() > 0) { 3656 WatcherThread::start(); 3657 } 3658 } 3659 3660 // Give os specific code one last chance to start 3661 os::init_3(); 3662 3663 create_vm_timer.end(); 3664#ifdef ASSERT 3665 _vm_complete = true; 3666#endif 3667 return JNI_OK; 3668} 3669 3670// type for the Agent_OnLoad and JVM_OnLoad entry points 3671extern "C" { 3672 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3673} 3674// Find a command line agent library and return its entry point for 3675// -agentlib: -agentpath: -Xrun 3676// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3677static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3678 OnLoadEntry_t on_load_entry = NULL; 3679 void *library = NULL; 3680 3681 if (!agent->valid()) { 3682 char buffer[JVM_MAXPATHLEN]; 3683 char ebuf[1024]; 3684 const char *name = agent->name(); 3685 const char *msg = "Could not find agent library "; 3686 3687 // First check to see if agent is statically linked into executable 3688 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3689 library = agent->os_lib(); 3690 } else if (agent->is_absolute_path()) { 3691 library = os::dll_load(name, ebuf, sizeof ebuf); 3692 if (library == NULL) { 3693 const char *sub_msg = " in absolute path, with error: "; 3694 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3695 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3696 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3697 // If we can't find the agent, exit. 3698 vm_exit_during_initialization(buf, NULL); 3699 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3700 } 3701 } else { 3702 // Try to load the agent from the standard dll directory 3703 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3704 name)) { 3705 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3706 } 3707 if (library == NULL) { // Try the local directory 3708 char ns[1] = {0}; 3709 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3710 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3711 } 3712 if (library == NULL) { 3713 const char *sub_msg = " on the library path, with error: "; 3714 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3715 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3716 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3717 // If we can't find the agent, exit. 3718 vm_exit_during_initialization(buf, NULL); 3719 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3720 } 3721 } 3722 } 3723 agent->set_os_lib(library); 3724 agent->set_valid(); 3725 } 3726 3727 // Find the OnLoad function. 3728 on_load_entry = 3729 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3730 false, 3731 on_load_symbols, 3732 num_symbol_entries)); 3733 return on_load_entry; 3734} 3735 3736// Find the JVM_OnLoad entry point 3737static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3738 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3739 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3740} 3741 3742// Find the Agent_OnLoad entry point 3743static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3744 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3745 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3746} 3747 3748// For backwards compatibility with -Xrun 3749// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3750// treated like -agentpath: 3751// Must be called before agent libraries are created 3752void Threads::convert_vm_init_libraries_to_agents() { 3753 AgentLibrary* agent; 3754 AgentLibrary* next; 3755 3756 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3757 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3758 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3759 3760 // If there is an JVM_OnLoad function it will get called later, 3761 // otherwise see if there is an Agent_OnLoad 3762 if (on_load_entry == NULL) { 3763 on_load_entry = lookup_agent_on_load(agent); 3764 if (on_load_entry != NULL) { 3765 // switch it to the agent list -- so that Agent_OnLoad will be called, 3766 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3767 Arguments::convert_library_to_agent(agent); 3768 } else { 3769 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3770 } 3771 } 3772 } 3773} 3774 3775// Create agents for -agentlib: -agentpath: and converted -Xrun 3776// Invokes Agent_OnLoad 3777// Called very early -- before JavaThreads exist 3778void Threads::create_vm_init_agents() { 3779 extern struct JavaVM_ main_vm; 3780 AgentLibrary* agent; 3781 3782 JvmtiExport::enter_onload_phase(); 3783 3784 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3785 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3786 3787 if (on_load_entry != NULL) { 3788 // Invoke the Agent_OnLoad function 3789 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3790 if (err != JNI_OK) { 3791 vm_exit_during_initialization("agent library failed to init", agent->name()); 3792 } 3793 } else { 3794 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3795 } 3796 } 3797 JvmtiExport::enter_primordial_phase(); 3798} 3799 3800extern "C" { 3801 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3802} 3803 3804void Threads::shutdown_vm_agents() { 3805 // Send any Agent_OnUnload notifications 3806 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3807 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3808 extern struct JavaVM_ main_vm; 3809 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3810 3811 // Find the Agent_OnUnload function. 3812 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3813 os::find_agent_function(agent, 3814 false, 3815 on_unload_symbols, 3816 num_symbol_entries)); 3817 3818 // Invoke the Agent_OnUnload function 3819 if (unload_entry != NULL) { 3820 JavaThread* thread = JavaThread::current(); 3821 ThreadToNativeFromVM ttn(thread); 3822 HandleMark hm(thread); 3823 (*unload_entry)(&main_vm); 3824 } 3825 } 3826} 3827 3828// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3829// Invokes JVM_OnLoad 3830void Threads::create_vm_init_libraries() { 3831 extern struct JavaVM_ main_vm; 3832 AgentLibrary* agent; 3833 3834 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3835 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3836 3837 if (on_load_entry != NULL) { 3838 // Invoke the JVM_OnLoad function 3839 JavaThread* thread = JavaThread::current(); 3840 ThreadToNativeFromVM ttn(thread); 3841 HandleMark hm(thread); 3842 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3843 if (err != JNI_OK) { 3844 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3845 } 3846 } else { 3847 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3848 } 3849 } 3850} 3851 3852// Last thread running calls java.lang.Shutdown.shutdown() 3853void JavaThread::invoke_shutdown_hooks() { 3854 HandleMark hm(this); 3855 3856 // We could get here with a pending exception, if so clear it now. 3857 if (this->has_pending_exception()) { 3858 this->clear_pending_exception(); 3859 } 3860 3861 EXCEPTION_MARK; 3862 Klass* k = 3863 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3864 THREAD); 3865 if (k != NULL) { 3866 // SystemDictionary::resolve_or_null will return null if there was 3867 // an exception. If we cannot load the Shutdown class, just don't 3868 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3869 // and finalizers (if runFinalizersOnExit is set) won't be run. 3870 // Note that if a shutdown hook was registered or runFinalizersOnExit 3871 // was called, the Shutdown class would have already been loaded 3872 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3873 instanceKlassHandle shutdown_klass (THREAD, k); 3874 JavaValue result(T_VOID); 3875 JavaCalls::call_static(&result, 3876 shutdown_klass, 3877 vmSymbols::shutdown_method_name(), 3878 vmSymbols::void_method_signature(), 3879 THREAD); 3880 } 3881 CLEAR_PENDING_EXCEPTION; 3882} 3883 3884// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3885// the program falls off the end of main(). Another VM exit path is through 3886// vm_exit() when the program calls System.exit() to return a value or when 3887// there is a serious error in VM. The two shutdown paths are not exactly 3888// the same, but they share Shutdown.shutdown() at Java level and before_exit() 3889// and VM_Exit op at VM level. 3890// 3891// Shutdown sequence: 3892// + Shutdown native memory tracking if it is on 3893// + Wait until we are the last non-daemon thread to execute 3894// <-- every thing is still working at this moment --> 3895// + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3896// shutdown hooks, run finalizers if finalization-on-exit 3897// + Call before_exit(), prepare for VM exit 3898// > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3899// currently the only user of this mechanism is File.deleteOnExit()) 3900// > stop flat profiler, StatSampler, watcher thread, CMS threads, 3901// post thread end and vm death events to JVMTI, 3902// stop signal thread 3903// + Call JavaThread::exit(), it will: 3904// > release JNI handle blocks, remove stack guard pages 3905// > remove this thread from Threads list 3906// <-- no more Java code from this thread after this point --> 3907// + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3908// the compiler threads at safepoint 3909// <-- do not use anything that could get blocked by Safepoint --> 3910// + Disable tracing at JNI/JVM barriers 3911// + Set _vm_exited flag for threads that are still running native code 3912// + Delete this thread 3913// + Call exit_globals() 3914// > deletes tty 3915// > deletes PerfMemory resources 3916// + Return to caller 3917 3918bool Threads::destroy_vm() { 3919 JavaThread* thread = JavaThread::current(); 3920 3921#ifdef ASSERT 3922 _vm_complete = false; 3923#endif 3924 // Wait until we are the last non-daemon thread to execute 3925 { MutexLocker nu(Threads_lock); 3926 while (Threads::number_of_non_daemon_threads() > 1 ) 3927 // This wait should make safepoint checks, wait without a timeout, 3928 // and wait as a suspend-equivalent condition. 3929 // 3930 // Note: If the FlatProfiler is running and this thread is waiting 3931 // for another non-daemon thread to finish, then the FlatProfiler 3932 // is waiting for the external suspend request on this thread to 3933 // complete. wait_for_ext_suspend_completion() will eventually 3934 // timeout, but that takes time. Making this wait a suspend- 3935 // equivalent condition solves that timeout problem. 3936 // 3937 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3938 Mutex::_as_suspend_equivalent_flag); 3939 } 3940 3941 // Hang forever on exit if we are reporting an error. 3942 if (ShowMessageBoxOnError && is_error_reported()) { 3943 os::infinite_sleep(); 3944 } 3945 os::wait_for_keypress_at_exit(); 3946 3947 if (JDK_Version::is_jdk12x_version()) { 3948 // We are the last thread running, so check if finalizers should be run. 3949 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3950 HandleMark rm(thread); 3951 Universe::run_finalizers_on_exit(); 3952 } else { 3953 // run Java level shutdown hooks 3954 thread->invoke_shutdown_hooks(); 3955 } 3956 3957 before_exit(thread); 3958 3959 thread->exit(true); 3960 3961 // Stop VM thread. 3962 { 3963 // 4945125 The vm thread comes to a safepoint during exit. 3964 // GC vm_operations can get caught at the safepoint, and the 3965 // heap is unparseable if they are caught. Grab the Heap_lock 3966 // to prevent this. The GC vm_operations will not be able to 3967 // queue until after the vm thread is dead. 3968 // After this point, we'll never emerge out of the safepoint before 3969 // the VM exits, so concurrent GC threads do not need to be explicitly 3970 // stopped; they remain inactive until the process exits. 3971 // Note: some concurrent G1 threads may be running during a safepoint, 3972 // but these will not be accessing the heap, just some G1-specific side 3973 // data structures that are not accessed by any other threads but them 3974 // after this point in a terminal safepoint. 3975 3976 MutexLocker ml(Heap_lock); 3977 3978 VMThread::wait_for_vm_thread_exit(); 3979 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3980 VMThread::destroy(); 3981 } 3982 3983 // clean up ideal graph printers 3984#if defined(COMPILER2) && !defined(PRODUCT) 3985 IdealGraphPrinter::clean_up(); 3986#endif 3987 3988 // Now, all Java threads are gone except daemon threads. Daemon threads 3989 // running Java code or in VM are stopped by the Safepoint. However, 3990 // daemon threads executing native code are still running. But they 3991 // will be stopped at native=>Java/VM barriers. Note that we can't 3992 // simply kill or suspend them, as it is inherently deadlock-prone. 3993 3994#ifndef PRODUCT 3995 // disable function tracing at JNI/JVM barriers 3996 TraceJNICalls = false; 3997 TraceJVMCalls = false; 3998 TraceRuntimeCalls = false; 3999#endif 4000 4001 VM_Exit::set_vm_exited(); 4002 4003 notify_vm_shutdown(); 4004 4005 delete thread; 4006 4007 // exit_globals() will delete tty 4008 exit_globals(); 4009 4010 return true; 4011} 4012 4013 4014jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4015 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4016 return is_supported_jni_version(version); 4017} 4018 4019 4020jboolean Threads::is_supported_jni_version(jint version) { 4021 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4022 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4023 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4024 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4025 return JNI_FALSE; 4026} 4027 4028 4029void Threads::add(JavaThread* p, bool force_daemon) { 4030 // The threads lock must be owned at this point 4031 assert_locked_or_safepoint(Threads_lock); 4032 4033 // See the comment for this method in thread.hpp for its purpose and 4034 // why it is called here. 4035 p->initialize_queues(); 4036 p->set_next(_thread_list); 4037 _thread_list = p; 4038 _number_of_threads++; 4039 oop threadObj = p->threadObj(); 4040 bool daemon = true; 4041 // Bootstrapping problem: threadObj can be null for initial 4042 // JavaThread (or for threads attached via JNI) 4043 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4044 _number_of_non_daemon_threads++; 4045 daemon = false; 4046 } 4047 4048 p->set_safepoint_visible(true); 4049 4050 ThreadService::add_thread(p, daemon); 4051 4052 // Possible GC point. 4053 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4054} 4055 4056void Threads::remove(JavaThread* p) { 4057 // Extra scope needed for Thread_lock, so we can check 4058 // that we do not remove thread without safepoint code notice 4059 { MutexLocker ml(Threads_lock); 4060 4061 assert(includes(p), "p must be present"); 4062 4063 JavaThread* current = _thread_list; 4064 JavaThread* prev = NULL; 4065 4066 while (current != p) { 4067 prev = current; 4068 current = current->next(); 4069 } 4070 4071 if (prev) { 4072 prev->set_next(current->next()); 4073 } else { 4074 _thread_list = p->next(); 4075 } 4076 _number_of_threads--; 4077 oop threadObj = p->threadObj(); 4078 bool daemon = true; 4079 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4080 _number_of_non_daemon_threads--; 4081 daemon = false; 4082 4083 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4084 // on destroy_vm will wake up. 4085 if (number_of_non_daemon_threads() == 1) 4086 Threads_lock->notify_all(); 4087 } 4088 ThreadService::remove_thread(p, daemon); 4089 4090 // Make sure that safepoint code disregard this thread. This is needed since 4091 // the thread might mess around with locks after this point. This can cause it 4092 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4093 // of this thread since it is removed from the queue. 4094 p->set_terminated_value(); 4095 4096 // Now, this thread is not visible to safepoint 4097 p->set_safepoint_visible(false); 4098 // once the thread becomes safepoint invisible, we can not use its per-thread 4099 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4100 // to release its per-thread recorder here. 4101 MemTracker::thread_exiting(p); 4102 } // unlock Threads_lock 4103 4104 // Since Events::log uses a lock, we grab it outside the Threads_lock 4105 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4106} 4107 4108// Threads_lock must be held when this is called (or must be called during a safepoint) 4109bool Threads::includes(JavaThread* p) { 4110 assert(Threads_lock->is_locked(), "sanity check"); 4111 ALL_JAVA_THREADS(q) { 4112 if (q == p ) { 4113 return true; 4114 } 4115 } 4116 return false; 4117} 4118 4119// Operations on the Threads list for GC. These are not explicitly locked, 4120// but the garbage collector must provide a safe context for them to run. 4121// In particular, these things should never be called when the Threads_lock 4122// is held by some other thread. (Note: the Safepoint abstraction also 4123// uses the Threads_lock to guarantee this property. It also makes sure that 4124// all threads gets blocked when exiting or starting). 4125 4126void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4127 ALL_JAVA_THREADS(p) { 4128 p->oops_do(f, cld_f, cf); 4129 } 4130 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4131} 4132 4133void Threads::possibly_parallel_oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4134 // Introduce a mechanism allowing parallel threads to claim threads as 4135 // root groups. Overhead should be small enough to use all the time, 4136 // even in sequential code. 4137 SharedHeap* sh = SharedHeap::heap(); 4138 // Cannot yet substitute active_workers for n_par_threads 4139 // because of G1CollectedHeap::verify() use of 4140 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4141 // turn off parallelism in process_strong_roots while active_workers 4142 // is being used for parallelism elsewhere. 4143 bool is_par = sh->n_par_threads() > 0; 4144 assert(!is_par || 4145 (SharedHeap::heap()->n_par_threads() == 4146 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4147 int cp = SharedHeap::heap()->strong_roots_parity(); 4148 ALL_JAVA_THREADS(p) { 4149 if (p->claim_oops_do(is_par, cp)) { 4150 p->oops_do(f, cld_f, cf); 4151 } 4152 } 4153 VMThread* vmt = VMThread::vm_thread(); 4154 if (vmt->claim_oops_do(is_par, cp)) { 4155 vmt->oops_do(f, cld_f, cf); 4156 } 4157} 4158 4159#if INCLUDE_ALL_GCS 4160// Used by ParallelScavenge 4161void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4162 ALL_JAVA_THREADS(p) { 4163 q->enqueue(new ThreadRootsTask(p)); 4164 } 4165 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4166} 4167 4168// Used by Parallel Old 4169void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4170 ALL_JAVA_THREADS(p) { 4171 q->enqueue(new ThreadRootsMarkingTask(p)); 4172 } 4173 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4174} 4175#endif // INCLUDE_ALL_GCS 4176 4177void Threads::nmethods_do(CodeBlobClosure* cf) { 4178 ALL_JAVA_THREADS(p) { 4179 p->nmethods_do(cf); 4180 } 4181 VMThread::vm_thread()->nmethods_do(cf); 4182} 4183 4184void Threads::metadata_do(void f(Metadata*)) { 4185 ALL_JAVA_THREADS(p) { 4186 p->metadata_do(f); 4187 } 4188} 4189 4190void Threads::gc_epilogue() { 4191 ALL_JAVA_THREADS(p) { 4192 p->gc_epilogue(); 4193 } 4194} 4195 4196void Threads::gc_prologue() { 4197 ALL_JAVA_THREADS(p) { 4198 p->gc_prologue(); 4199 } 4200} 4201 4202void Threads::deoptimized_wrt_marked_nmethods() { 4203 ALL_JAVA_THREADS(p) { 4204 p->deoptimized_wrt_marked_nmethods(); 4205 } 4206} 4207 4208 4209// Get count Java threads that are waiting to enter the specified monitor. 4210GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4211 address monitor, bool doLock) { 4212 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4213 "must grab Threads_lock or be at safepoint"); 4214 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4215 4216 int i = 0; 4217 { 4218 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4219 ALL_JAVA_THREADS(p) { 4220 if (p->is_Compiler_thread()) continue; 4221 4222 address pending = (address)p->current_pending_monitor(); 4223 if (pending == monitor) { // found a match 4224 if (i < count) result->append(p); // save the first count matches 4225 i++; 4226 } 4227 } 4228 } 4229 return result; 4230} 4231 4232 4233JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4234 assert(doLock || 4235 Threads_lock->owned_by_self() || 4236 SafepointSynchronize::is_at_safepoint(), 4237 "must grab Threads_lock or be at safepoint"); 4238 4239 // NULL owner means not locked so we can skip the search 4240 if (owner == NULL) return NULL; 4241 4242 { 4243 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4244 ALL_JAVA_THREADS(p) { 4245 // first, see if owner is the address of a Java thread 4246 if (owner == (address)p) return p; 4247 } 4248 } 4249 // Cannot assert on lack of success here since this function may be 4250 // used by code that is trying to report useful problem information 4251 // like deadlock detection. 4252 if (UseHeavyMonitors) return NULL; 4253 4254 // 4255 // If we didn't find a matching Java thread and we didn't force use of 4256 // heavyweight monitors, then the owner is the stack address of the 4257 // Lock Word in the owning Java thread's stack. 4258 // 4259 JavaThread* the_owner = NULL; 4260 { 4261 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4262 ALL_JAVA_THREADS(q) { 4263 if (q->is_lock_owned(owner)) { 4264 the_owner = q; 4265 break; 4266 } 4267 } 4268 } 4269 // cannot assert on lack of success here; see above comment 4270 return the_owner; 4271} 4272 4273// Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4274void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4275 char buf[32]; 4276 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4277 4278 st->print_cr("Full thread dump %s (%s %s):", 4279 Abstract_VM_Version::vm_name(), 4280 Abstract_VM_Version::vm_release(), 4281 Abstract_VM_Version::vm_info_string() 4282 ); 4283 st->cr(); 4284 4285#if INCLUDE_ALL_GCS 4286 // Dump concurrent locks 4287 ConcurrentLocksDump concurrent_locks; 4288 if (print_concurrent_locks) { 4289 concurrent_locks.dump_at_safepoint(); 4290 } 4291#endif // INCLUDE_ALL_GCS 4292 4293 ALL_JAVA_THREADS(p) { 4294 ResourceMark rm; 4295 p->print_on(st); 4296 if (print_stacks) { 4297 if (internal_format) { 4298 p->trace_stack(); 4299 } else { 4300 p->print_stack_on(st); 4301 } 4302 } 4303 st->cr(); 4304#if INCLUDE_ALL_GCS 4305 if (print_concurrent_locks) { 4306 concurrent_locks.print_locks_on(p, st); 4307 } 4308#endif // INCLUDE_ALL_GCS 4309 } 4310 4311 VMThread::vm_thread()->print_on(st); 4312 st->cr(); 4313 Universe::heap()->print_gc_threads_on(st); 4314 WatcherThread* wt = WatcherThread::watcher_thread(); 4315 if (wt != NULL) { 4316 wt->print_on(st); 4317 st->cr(); 4318 } 4319 CompileBroker::print_compiler_threads_on(st); 4320 st->flush(); 4321} 4322 4323// Threads::print_on_error() is called by fatal error handler. It's possible 4324// that VM is not at safepoint and/or current thread is inside signal handler. 4325// Don't print stack trace, as the stack may not be walkable. Don't allocate 4326// memory (even in resource area), it might deadlock the error handler. 4327void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4328 bool found_current = false; 4329 st->print_cr("Java Threads: ( => current thread )"); 4330 ALL_JAVA_THREADS(thread) { 4331 bool is_current = (current == thread); 4332 found_current = found_current || is_current; 4333 4334 st->print("%s", is_current ? "=>" : " "); 4335 4336 st->print(PTR_FORMAT, thread); 4337 st->print(" "); 4338 thread->print_on_error(st, buf, buflen); 4339 st->cr(); 4340 } 4341 st->cr(); 4342 4343 st->print_cr("Other Threads:"); 4344 if (VMThread::vm_thread()) { 4345 bool is_current = (current == VMThread::vm_thread()); 4346 found_current = found_current || is_current; 4347 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4348 4349 st->print(PTR_FORMAT, VMThread::vm_thread()); 4350 st->print(" "); 4351 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4352 st->cr(); 4353 } 4354 WatcherThread* wt = WatcherThread::watcher_thread(); 4355 if (wt != NULL) { 4356 bool is_current = (current == wt); 4357 found_current = found_current || is_current; 4358 st->print("%s", is_current ? "=>" : " "); 4359 4360 st->print(PTR_FORMAT, wt); 4361 st->print(" "); 4362 wt->print_on_error(st, buf, buflen); 4363 st->cr(); 4364 } 4365 if (!found_current) { 4366 st->cr(); 4367 st->print("=>" PTR_FORMAT " (exited) ", current); 4368 current->print_on_error(st, buf, buflen); 4369 st->cr(); 4370 } 4371} 4372 4373// Internal SpinLock and Mutex 4374// Based on ParkEvent 4375 4376// Ad-hoc mutual exclusion primitives: SpinLock and Mux 4377// 4378// We employ SpinLocks _only for low-contention, fixed-length 4379// short-duration critical sections where we're concerned 4380// about native mutex_t or HotSpot Mutex:: latency. 4381// The mux construct provides a spin-then-block mutual exclusion 4382// mechanism. 4383// 4384// Testing has shown that contention on the ListLock guarding gFreeList 4385// is common. If we implement ListLock as a simple SpinLock it's common 4386// for the JVM to devolve to yielding with little progress. This is true 4387// despite the fact that the critical sections protected by ListLock are 4388// extremely short. 4389// 4390// TODO-FIXME: ListLock should be of type SpinLock. 4391// We should make this a 1st-class type, integrated into the lock 4392// hierarchy as leaf-locks. Critically, the SpinLock structure 4393// should have sufficient padding to avoid false-sharing and excessive 4394// cache-coherency traffic. 4395 4396 4397typedef volatile int SpinLockT ; 4398 4399void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4400 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4401 return ; // normal fast-path return 4402 } 4403 4404 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4405 TEVENT (SpinAcquire - ctx) ; 4406 int ctr = 0 ; 4407 int Yields = 0 ; 4408 for (;;) { 4409 while (*adr != 0) { 4410 ++ctr ; 4411 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4412 if (Yields > 5) { 4413 os::naked_short_sleep(1); 4414 } else { 4415 os::NakedYield() ; 4416 ++Yields ; 4417 } 4418 } else { 4419 SpinPause() ; 4420 } 4421 } 4422 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4423 } 4424} 4425 4426void Thread::SpinRelease (volatile int * adr) { 4427 assert (*adr != 0, "invariant") ; 4428 OrderAccess::fence() ; // guarantee at least release consistency. 4429 // Roach-motel semantics. 4430 // It's safe if subsequent LDs and STs float "up" into the critical section, 4431 // but prior LDs and STs within the critical section can't be allowed 4432 // to reorder or float past the ST that releases the lock. 4433 *adr = 0 ; 4434} 4435 4436// muxAcquire and muxRelease: 4437// 4438// * muxAcquire and muxRelease support a single-word lock-word construct. 4439// The LSB of the word is set IFF the lock is held. 4440// The remainder of the word points to the head of a singly-linked list 4441// of threads blocked on the lock. 4442// 4443// * The current implementation of muxAcquire-muxRelease uses its own 4444// dedicated Thread._MuxEvent instance. If we're interested in 4445// minimizing the peak number of extant ParkEvent instances then 4446// we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4447// as certain invariants were satisfied. Specifically, care would need 4448// to be taken with regards to consuming unpark() "permits". 4449// A safe rule of thumb is that a thread would never call muxAcquire() 4450// if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4451// park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4452// consume an unpark() permit intended for monitorenter, for instance. 4453// One way around this would be to widen the restricted-range semaphore 4454// implemented in park(). Another alternative would be to provide 4455// multiple instances of the PlatformEvent() for each thread. One 4456// instance would be dedicated to muxAcquire-muxRelease, for instance. 4457// 4458// * Usage: 4459// -- Only as leaf locks 4460// -- for short-term locking only as muxAcquire does not perform 4461// thread state transitions. 4462// 4463// Alternatives: 4464// * We could implement muxAcquire and muxRelease with MCS or CLH locks 4465// but with parking or spin-then-park instead of pure spinning. 4466// * Use Taura-Oyama-Yonenzawa locks. 4467// * It's possible to construct a 1-0 lock if we encode the lockword as 4468// (List,LockByte). Acquire will CAS the full lockword while Release 4469// will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4470// acquiring threads use timers (ParkTimed) to detect and recover from 4471// the stranding window. Thread/Node structures must be aligned on 256-byte 4472// boundaries by using placement-new. 4473// * Augment MCS with advisory back-link fields maintained with CAS(). 4474// Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4475// The validity of the backlinks must be ratified before we trust the value. 4476// If the backlinks are invalid the exiting thread must back-track through the 4477// the forward links, which are always trustworthy. 4478// * Add a successor indication. The LockWord is currently encoded as 4479// (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4480// to provide the usual futile-wakeup optimization. 4481// See RTStt for details. 4482// * Consider schedctl.sc_nopreempt to cover the critical section. 4483// 4484 4485 4486typedef volatile intptr_t MutexT ; // Mux Lock-word 4487enum MuxBits { LOCKBIT = 1 } ; 4488 4489void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4490 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4491 if (w == 0) return ; 4492 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4493 return ; 4494 } 4495 4496 TEVENT (muxAcquire - Contention) ; 4497 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4498 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4499 for (;;) { 4500 int its = (os::is_MP() ? 100 : 0) + 1 ; 4501 4502 // Optional spin phase: spin-then-park strategy 4503 while (--its >= 0) { 4504 w = *Lock ; 4505 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4506 return ; 4507 } 4508 } 4509 4510 Self->reset() ; 4511 Self->OnList = intptr_t(Lock) ; 4512 // The following fence() isn't _strictly necessary as the subsequent 4513 // CAS() both serializes execution and ratifies the fetched *Lock value. 4514 OrderAccess::fence(); 4515 for (;;) { 4516 w = *Lock ; 4517 if ((w & LOCKBIT) == 0) { 4518 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4519 Self->OnList = 0 ; // hygiene - allows stronger asserts 4520 return ; 4521 } 4522 continue ; // Interference -- *Lock changed -- Just retry 4523 } 4524 assert (w & LOCKBIT, "invariant") ; 4525 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4526 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4527 } 4528 4529 while (Self->OnList != 0) { 4530 Self->park() ; 4531 } 4532 } 4533} 4534 4535void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4536 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4537 if (w == 0) return ; 4538 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4539 return ; 4540 } 4541 4542 TEVENT (muxAcquire - Contention) ; 4543 ParkEvent * ReleaseAfter = NULL ; 4544 if (ev == NULL) { 4545 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4546 } 4547 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4548 for (;;) { 4549 guarantee (ev->OnList == 0, "invariant") ; 4550 int its = (os::is_MP() ? 100 : 0) + 1 ; 4551 4552 // Optional spin phase: spin-then-park strategy 4553 while (--its >= 0) { 4554 w = *Lock ; 4555 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4556 if (ReleaseAfter != NULL) { 4557 ParkEvent::Release (ReleaseAfter) ; 4558 } 4559 return ; 4560 } 4561 } 4562 4563 ev->reset() ; 4564 ev->OnList = intptr_t(Lock) ; 4565 // The following fence() isn't _strictly necessary as the subsequent 4566 // CAS() both serializes execution and ratifies the fetched *Lock value. 4567 OrderAccess::fence(); 4568 for (;;) { 4569 w = *Lock ; 4570 if ((w & LOCKBIT) == 0) { 4571 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4572 ev->OnList = 0 ; 4573 // We call ::Release while holding the outer lock, thus 4574 // artificially lengthening the critical section. 4575 // Consider deferring the ::Release() until the subsequent unlock(), 4576 // after we've dropped the outer lock. 4577 if (ReleaseAfter != NULL) { 4578 ParkEvent::Release (ReleaseAfter) ; 4579 } 4580 return ; 4581 } 4582 continue ; // Interference -- *Lock changed -- Just retry 4583 } 4584 assert (w & LOCKBIT, "invariant") ; 4585 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4586 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4587 } 4588 4589 while (ev->OnList != 0) { 4590 ev->park() ; 4591 } 4592 } 4593} 4594 4595// Release() must extract a successor from the list and then wake that thread. 4596// It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4597// similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4598// Release() would : 4599// (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4600// (B) Extract a successor from the private list "in-hand" 4601// (C) attempt to CAS() the residual back into *Lock over null. 4602// If there were any newly arrived threads and the CAS() would fail. 4603// In that case Release() would detach the RATs, re-merge the list in-hand 4604// with the RATs and repeat as needed. Alternately, Release() might 4605// detach and extract a successor, but then pass the residual list to the wakee. 4606// The wakee would be responsible for reattaching and remerging before it 4607// competed for the lock. 4608// 4609// Both "pop" and DMR are immune from ABA corruption -- there can be 4610// multiple concurrent pushers, but only one popper or detacher. 4611// This implementation pops from the head of the list. This is unfair, 4612// but tends to provide excellent throughput as hot threads remain hot. 4613// (We wake recently run threads first). 4614 4615void Thread::muxRelease (volatile intptr_t * Lock) { 4616 for (;;) { 4617 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4618 assert (w & LOCKBIT, "invariant") ; 4619 if (w == LOCKBIT) return ; 4620 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4621 assert (List != NULL, "invariant") ; 4622 assert (List->OnList == intptr_t(Lock), "invariant") ; 4623 ParkEvent * nxt = List->ListNext ; 4624 4625 // The following CAS() releases the lock and pops the head element. 4626 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4627 continue ; 4628 } 4629 List->OnList = 0 ; 4630 OrderAccess::fence() ; 4631 List->unpark () ; 4632 return ; 4633 } 4634} 4635 4636 4637void Threads::verify() { 4638 ALL_JAVA_THREADS(p) { 4639 p->verify(); 4640 } 4641 VMThread* thread = VMThread::vm_thread(); 4642 if (thread != NULL) thread->verify(); 4643} 4644