thread.cpp revision 4989:5e3b6f79d280
1/* 2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "precompiled.hpp" 26#include "classfile/classLoader.hpp" 27#include "classfile/javaClasses.hpp" 28#include "classfile/systemDictionary.hpp" 29#include "classfile/vmSymbols.hpp" 30#include "code/scopeDesc.hpp" 31#include "compiler/compileBroker.hpp" 32#include "interpreter/interpreter.hpp" 33#include "interpreter/linkResolver.hpp" 34#include "interpreter/oopMapCache.hpp" 35#include "jvmtifiles/jvmtiEnv.hpp" 36#include "memory/gcLocker.inline.hpp" 37#include "memory/metaspaceShared.hpp" 38#include "memory/oopFactory.hpp" 39#include "memory/universe.inline.hpp" 40#include "oops/instanceKlass.hpp" 41#include "oops/objArrayOop.hpp" 42#include "oops/oop.inline.hpp" 43#include "oops/symbol.hpp" 44#include "prims/jvm_misc.hpp" 45#include "prims/jvmtiExport.hpp" 46#include "prims/jvmtiThreadState.hpp" 47#include "prims/privilegedStack.hpp" 48#include "runtime/arguments.hpp" 49#include "runtime/biasedLocking.hpp" 50#include "runtime/deoptimization.hpp" 51#include "runtime/fprofiler.hpp" 52#include "runtime/frame.inline.hpp" 53#include "runtime/init.hpp" 54#include "runtime/interfaceSupport.hpp" 55#include "runtime/java.hpp" 56#include "runtime/javaCalls.hpp" 57#include "runtime/jniPeriodicChecker.hpp" 58#include "runtime/memprofiler.hpp" 59#include "runtime/mutexLocker.hpp" 60#include "runtime/objectMonitor.hpp" 61#include "runtime/osThread.hpp" 62#include "runtime/safepoint.hpp" 63#include "runtime/sharedRuntime.hpp" 64#include "runtime/statSampler.hpp" 65#include "runtime/stubRoutines.hpp" 66#include "runtime/task.hpp" 67#include "runtime/thread.inline.hpp" 68#include "runtime/threadCritical.hpp" 69#include "runtime/threadLocalStorage.hpp" 70#include "runtime/vframe.hpp" 71#include "runtime/vframeArray.hpp" 72#include "runtime/vframe_hp.hpp" 73#include "runtime/vmThread.hpp" 74#include "runtime/vm_operations.hpp" 75#include "services/attachListener.hpp" 76#include "services/management.hpp" 77#include "services/memTracker.hpp" 78#include "services/threadService.hpp" 79#include "trace/tracing.hpp" 80#include "trace/traceMacros.hpp" 81#include "utilities/defaultStream.hpp" 82#include "utilities/dtrace.hpp" 83#include "utilities/events.hpp" 84#include "utilities/preserveException.hpp" 85#include "utilities/macros.hpp" 86#ifdef TARGET_OS_FAMILY_linux 87# include "os_linux.inline.hpp" 88#endif 89#ifdef TARGET_OS_FAMILY_solaris 90# include "os_solaris.inline.hpp" 91#endif 92#ifdef TARGET_OS_FAMILY_windows 93# include "os_windows.inline.hpp" 94#endif 95#ifdef TARGET_OS_FAMILY_bsd 96# include "os_bsd.inline.hpp" 97#endif 98#if INCLUDE_ALL_GCS 99#include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 100#include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 101#include "gc_implementation/parallelScavenge/pcTasks.hpp" 102#endif // INCLUDE_ALL_GCS 103#ifdef COMPILER1 104#include "c1/c1_Compiler.hpp" 105#endif 106#ifdef COMPILER2 107#include "opto/c2compiler.hpp" 108#include "opto/idealGraphPrinter.hpp" 109#endif 110 111#ifdef DTRACE_ENABLED 112 113// Only bother with this argument setup if dtrace is available 114 115#ifndef USDT2 116HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 117HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 118HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 119 intptr_t, intptr_t, bool); 120HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 121 intptr_t, intptr_t, bool); 122 123#define DTRACE_THREAD_PROBE(probe, javathread) \ 124 { \ 125 ResourceMark rm(this); \ 126 int len = 0; \ 127 const char* name = (javathread)->get_thread_name(); \ 128 len = strlen(name); \ 129 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 130 name, len, \ 131 java_lang_Thread::thread_id((javathread)->threadObj()), \ 132 (javathread)->osthread()->thread_id(), \ 133 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 134 } 135 136#else /* USDT2 */ 137 138#define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START 139#define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP 140 141#define DTRACE_THREAD_PROBE(probe, javathread) \ 142 { \ 143 ResourceMark rm(this); \ 144 int len = 0; \ 145 const char* name = (javathread)->get_thread_name(); \ 146 len = strlen(name); \ 147 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 148 (char *) name, len, \ 149 java_lang_Thread::thread_id((javathread)->threadObj()), \ 150 (uintptr_t) (javathread)->osthread()->thread_id(), \ 151 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 152 } 153 154#endif /* USDT2 */ 155 156#else // ndef DTRACE_ENABLED 157 158#define DTRACE_THREAD_PROBE(probe, javathread) 159 160#endif // ndef DTRACE_ENABLED 161 162 163// Class hierarchy 164// - Thread 165// - VMThread 166// - WatcherThread 167// - ConcurrentMarkSweepThread 168// - JavaThread 169// - CompilerThread 170 171// ======= Thread ======== 172// Support for forcing alignment of thread objects for biased locking 173void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 174 if (UseBiasedLocking) { 175 const int alignment = markOopDesc::biased_lock_alignment; 176 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 178 : AllocateHeap(aligned_size, flags, CURRENT_PC, 179 AllocFailStrategy::RETURN_NULL); 180 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 183 "JavaThread alignment code overflowed allocated storage"); 184 if (TraceBiasedLocking) { 185 if (aligned_addr != real_malloc_addr) 186 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 187 real_malloc_addr, aligned_addr); 188 } 189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 190 return aligned_addr; 191 } else { 192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 194 } 195} 196 197void Thread::operator delete(void* p) { 198 if (UseBiasedLocking) { 199 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 200 FreeHeap(real_malloc_addr, mtThread); 201 } else { 202 FreeHeap(p, mtThread); 203 } 204} 205 206 207// Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 208// JavaThread 209 210 211Thread::Thread() { 212 // stack and get_thread 213 set_stack_base(NULL); 214 set_stack_size(0); 215 set_self_raw_id(0); 216 set_lgrp_id(-1); 217 218 // allocated data structures 219 set_osthread(NULL); 220 set_resource_area(new (mtThread)ResourceArea()); 221 DEBUG_ONLY(_current_resource_mark = NULL;) 222 set_handle_area(new (mtThread) HandleArea(NULL)); 223 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 224 set_active_handles(NULL); 225 set_free_handle_block(NULL); 226 set_last_handle_mark(NULL); 227 228 // This initial value ==> never claimed. 229 _oops_do_parity = 0; 230 231 // the handle mark links itself to last_handle_mark 232 new HandleMark(this); 233 234 // plain initialization 235 debug_only(_owned_locks = NULL;) 236 debug_only(_allow_allocation_count = 0;) 237 NOT_PRODUCT(_allow_safepoint_count = 0;) 238 NOT_PRODUCT(_skip_gcalot = false;) 239 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;) 240 _jvmti_env_iteration_count = 0; 241 set_allocated_bytes(0); 242 _vm_operation_started_count = 0; 243 _vm_operation_completed_count = 0; 244 _current_pending_monitor = NULL; 245 _current_pending_monitor_is_from_java = true; 246 _current_waiting_monitor = NULL; 247 _num_nested_signal = 0; 248 omFreeList = NULL ; 249 omFreeCount = 0 ; 250 omFreeProvision = 32 ; 251 omInUseList = NULL ; 252 omInUseCount = 0 ; 253 254#ifdef ASSERT 255 _visited_for_critical_count = false; 256#endif 257 258 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 259 _suspend_flags = 0; 260 261 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 262 _hashStateX = os::random() ; 263 _hashStateY = 842502087 ; 264 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 265 _hashStateW = 273326509 ; 266 267 _OnTrap = 0 ; 268 _schedctl = NULL ; 269 _Stalled = 0 ; 270 _TypeTag = 0x2BAD ; 271 272 // Many of the following fields are effectively final - immutable 273 // Note that nascent threads can't use the Native Monitor-Mutex 274 // construct until the _MutexEvent is initialized ... 275 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 276 // we might instead use a stack of ParkEvents that we could provision on-demand. 277 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 278 // and ::Release() 279 _ParkEvent = ParkEvent::Allocate (this) ; 280 _SleepEvent = ParkEvent::Allocate (this) ; 281 _MutexEvent = ParkEvent::Allocate (this) ; 282 _MuxEvent = ParkEvent::Allocate (this) ; 283 284#ifdef CHECK_UNHANDLED_OOPS 285 if (CheckUnhandledOops) { 286 _unhandled_oops = new UnhandledOops(this); 287 } 288#endif // CHECK_UNHANDLED_OOPS 289#ifdef ASSERT 290 if (UseBiasedLocking) { 291 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 292 assert(this == _real_malloc_address || 293 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 294 "bug in forced alignment of thread objects"); 295 } 296#endif /* ASSERT */ 297} 298 299void Thread::initialize_thread_local_storage() { 300 // Note: Make sure this method only calls 301 // non-blocking operations. Otherwise, it might not work 302 // with the thread-startup/safepoint interaction. 303 304 // During Java thread startup, safepoint code should allow this 305 // method to complete because it may need to allocate memory to 306 // store information for the new thread. 307 308 // initialize structure dependent on thread local storage 309 ThreadLocalStorage::set_thread(this); 310} 311 312void Thread::record_stack_base_and_size() { 313 set_stack_base(os::current_stack_base()); 314 set_stack_size(os::current_stack_size()); 315 // CR 7190089: on Solaris, primordial thread's stack is adjusted 316 // in initialize_thread(). Without the adjustment, stack size is 317 // incorrect if stack is set to unlimited (ulimit -s unlimited). 318 // So far, only Solaris has real implementation of initialize_thread(). 319 // 320 // set up any platform-specific state. 321 os::initialize_thread(this); 322 323#if INCLUDE_NMT 324 // record thread's native stack, stack grows downward 325 address stack_low_addr = stack_base() - stack_size(); 326 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 327 CURRENT_PC); 328#endif // INCLUDE_NMT 329} 330 331 332Thread::~Thread() { 333 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 334 ObjectSynchronizer::omFlush (this) ; 335 336 // stack_base can be NULL if the thread is never started or exited before 337 // record_stack_base_and_size called. Although, we would like to ensure 338 // that all started threads do call record_stack_base_and_size(), there is 339 // not proper way to enforce that. 340#if INCLUDE_NMT 341 if (_stack_base != NULL) { 342 address low_stack_addr = stack_base() - stack_size(); 343 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); 344#ifdef ASSERT 345 set_stack_base(NULL); 346#endif 347 } 348#endif // INCLUDE_NMT 349 350 // deallocate data structures 351 delete resource_area(); 352 // since the handle marks are using the handle area, we have to deallocated the root 353 // handle mark before deallocating the thread's handle area, 354 assert(last_handle_mark() != NULL, "check we have an element"); 355 delete last_handle_mark(); 356 assert(last_handle_mark() == NULL, "check we have reached the end"); 357 358 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 359 // We NULL out the fields for good hygiene. 360 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 361 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 362 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 363 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 364 365 delete handle_area(); 366 delete metadata_handles(); 367 368 // osthread() can be NULL, if creation of thread failed. 369 if (osthread() != NULL) os::free_thread(osthread()); 370 371 delete _SR_lock; 372 373 // clear thread local storage if the Thread is deleting itself 374 if (this == Thread::current()) { 375 ThreadLocalStorage::set_thread(NULL); 376 } else { 377 // In the case where we're not the current thread, invalidate all the 378 // caches in case some code tries to get the current thread or the 379 // thread that was destroyed, and gets stale information. 380 ThreadLocalStorage::invalidate_all(); 381 } 382 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 383} 384 385// NOTE: dummy function for assertion purpose. 386void Thread::run() { 387 ShouldNotReachHere(); 388} 389 390#ifdef ASSERT 391// Private method to check for dangling thread pointer 392void check_for_dangling_thread_pointer(Thread *thread) { 393 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 394 "possibility of dangling Thread pointer"); 395} 396#endif 397 398 399#ifndef PRODUCT 400// Tracing method for basic thread operations 401void Thread::trace(const char* msg, const Thread* const thread) { 402 if (!TraceThreadEvents) return; 403 ResourceMark rm; 404 ThreadCritical tc; 405 const char *name = "non-Java thread"; 406 int prio = -1; 407 if (thread->is_Java_thread() 408 && !thread->is_Compiler_thread()) { 409 // The Threads_lock must be held to get information about 410 // this thread but may not be in some situations when 411 // tracing thread events. 412 bool release_Threads_lock = false; 413 if (!Threads_lock->owned_by_self()) { 414 Threads_lock->lock(); 415 release_Threads_lock = true; 416 } 417 JavaThread* jt = (JavaThread *)thread; 418 name = (char *)jt->get_thread_name(); 419 oop thread_oop = jt->threadObj(); 420 if (thread_oop != NULL) { 421 prio = java_lang_Thread::priority(thread_oop); 422 } 423 if (release_Threads_lock) { 424 Threads_lock->unlock(); 425 } 426 } 427 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 428} 429#endif 430 431 432ThreadPriority Thread::get_priority(const Thread* const thread) { 433 trace("get priority", thread); 434 ThreadPriority priority; 435 // Can return an error! 436 (void)os::get_priority(thread, priority); 437 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 438 return priority; 439} 440 441void Thread::set_priority(Thread* thread, ThreadPriority priority) { 442 trace("set priority", thread); 443 debug_only(check_for_dangling_thread_pointer(thread);) 444 // Can return an error! 445 (void)os::set_priority(thread, priority); 446} 447 448 449void Thread::start(Thread* thread) { 450 trace("start", thread); 451 // Start is different from resume in that its safety is guaranteed by context or 452 // being called from a Java method synchronized on the Thread object. 453 if (!DisableStartThread) { 454 if (thread->is_Java_thread()) { 455 // Initialize the thread state to RUNNABLE before starting this thread. 456 // Can not set it after the thread started because we do not know the 457 // exact thread state at that time. It could be in MONITOR_WAIT or 458 // in SLEEPING or some other state. 459 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 460 java_lang_Thread::RUNNABLE); 461 } 462 os::start_thread(thread); 463 } 464} 465 466// Enqueue a VM_Operation to do the job for us - sometime later 467void Thread::send_async_exception(oop java_thread, oop java_throwable) { 468 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 469 VMThread::execute(vm_stop); 470} 471 472 473// 474// Check if an external suspend request has completed (or has been 475// cancelled). Returns true if the thread is externally suspended and 476// false otherwise. 477// 478// The bits parameter returns information about the code path through 479// the routine. Useful for debugging: 480// 481// set in is_ext_suspend_completed(): 482// 0x00000001 - routine was entered 483// 0x00000010 - routine return false at end 484// 0x00000100 - thread exited (return false) 485// 0x00000200 - suspend request cancelled (return false) 486// 0x00000400 - thread suspended (return true) 487// 0x00001000 - thread is in a suspend equivalent state (return true) 488// 0x00002000 - thread is native and walkable (return true) 489// 0x00004000 - thread is native_trans and walkable (needed retry) 490// 491// set in wait_for_ext_suspend_completion(): 492// 0x00010000 - routine was entered 493// 0x00020000 - suspend request cancelled before loop (return false) 494// 0x00040000 - thread suspended before loop (return true) 495// 0x00080000 - suspend request cancelled in loop (return false) 496// 0x00100000 - thread suspended in loop (return true) 497// 0x00200000 - suspend not completed during retry loop (return false) 498// 499 500// Helper class for tracing suspend wait debug bits. 501// 502// 0x00000100 indicates that the target thread exited before it could 503// self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 504// 0x00080000 each indicate a cancelled suspend request so they don't 505// count as wait failures either. 506#define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 507 508class TraceSuspendDebugBits : public StackObj { 509 private: 510 JavaThread * jt; 511 bool is_wait; 512 bool called_by_wait; // meaningful when !is_wait 513 uint32_t * bits; 514 515 public: 516 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 517 uint32_t *_bits) { 518 jt = _jt; 519 is_wait = _is_wait; 520 called_by_wait = _called_by_wait; 521 bits = _bits; 522 } 523 524 ~TraceSuspendDebugBits() { 525 if (!is_wait) { 526#if 1 527 // By default, don't trace bits for is_ext_suspend_completed() calls. 528 // That trace is very chatty. 529 return; 530#else 531 if (!called_by_wait) { 532 // If tracing for is_ext_suspend_completed() is enabled, then only 533 // trace calls to it from wait_for_ext_suspend_completion() 534 return; 535 } 536#endif 537 } 538 539 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 540 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 541 MutexLocker ml(Threads_lock); // needed for get_thread_name() 542 ResourceMark rm; 543 544 tty->print_cr( 545 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 546 jt->get_thread_name(), *bits); 547 548 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 549 } 550 } 551 } 552}; 553#undef DEBUG_FALSE_BITS 554 555 556bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 557 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 558 559 bool did_trans_retry = false; // only do thread_in_native_trans retry once 560 bool do_trans_retry; // flag to force the retry 561 562 *bits |= 0x00000001; 563 564 do { 565 do_trans_retry = false; 566 567 if (is_exiting()) { 568 // Thread is in the process of exiting. This is always checked 569 // first to reduce the risk of dereferencing a freed JavaThread. 570 *bits |= 0x00000100; 571 return false; 572 } 573 574 if (!is_external_suspend()) { 575 // Suspend request is cancelled. This is always checked before 576 // is_ext_suspended() to reduce the risk of a rogue resume 577 // confusing the thread that made the suspend request. 578 *bits |= 0x00000200; 579 return false; 580 } 581 582 if (is_ext_suspended()) { 583 // thread is suspended 584 *bits |= 0x00000400; 585 return true; 586 } 587 588 // Now that we no longer do hard suspends of threads running 589 // native code, the target thread can be changing thread state 590 // while we are in this routine: 591 // 592 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 593 // 594 // We save a copy of the thread state as observed at this moment 595 // and make our decision about suspend completeness based on the 596 // copy. This closes the race where the thread state is seen as 597 // _thread_in_native_trans in the if-thread_blocked check, but is 598 // seen as _thread_blocked in if-thread_in_native_trans check. 599 JavaThreadState save_state = thread_state(); 600 601 if (save_state == _thread_blocked && is_suspend_equivalent()) { 602 // If the thread's state is _thread_blocked and this blocking 603 // condition is known to be equivalent to a suspend, then we can 604 // consider the thread to be externally suspended. This means that 605 // the code that sets _thread_blocked has been modified to do 606 // self-suspension if the blocking condition releases. We also 607 // used to check for CONDVAR_WAIT here, but that is now covered by 608 // the _thread_blocked with self-suspension check. 609 // 610 // Return true since we wouldn't be here unless there was still an 611 // external suspend request. 612 *bits |= 0x00001000; 613 return true; 614 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 615 // Threads running native code will self-suspend on native==>VM/Java 616 // transitions. If its stack is walkable (should always be the case 617 // unless this function is called before the actual java_suspend() 618 // call), then the wait is done. 619 *bits |= 0x00002000; 620 return true; 621 } else if (!called_by_wait && !did_trans_retry && 622 save_state == _thread_in_native_trans && 623 frame_anchor()->walkable()) { 624 // The thread is transitioning from thread_in_native to another 625 // thread state. check_safepoint_and_suspend_for_native_trans() 626 // will force the thread to self-suspend. If it hasn't gotten 627 // there yet we may have caught the thread in-between the native 628 // code check above and the self-suspend. Lucky us. If we were 629 // called by wait_for_ext_suspend_completion(), then it 630 // will be doing the retries so we don't have to. 631 // 632 // Since we use the saved thread state in the if-statement above, 633 // there is a chance that the thread has already transitioned to 634 // _thread_blocked by the time we get here. In that case, we will 635 // make a single unnecessary pass through the logic below. This 636 // doesn't hurt anything since we still do the trans retry. 637 638 *bits |= 0x00004000; 639 640 // Once the thread leaves thread_in_native_trans for another 641 // thread state, we break out of this retry loop. We shouldn't 642 // need this flag to prevent us from getting back here, but 643 // sometimes paranoia is good. 644 did_trans_retry = true; 645 646 // We wait for the thread to transition to a more usable state. 647 for (int i = 1; i <= SuspendRetryCount; i++) { 648 // We used to do an "os::yield_all(i)" call here with the intention 649 // that yielding would increase on each retry. However, the parameter 650 // is ignored on Linux which means the yield didn't scale up. Waiting 651 // on the SR_lock below provides a much more predictable scale up for 652 // the delay. It also provides a simple/direct point to check for any 653 // safepoint requests from the VMThread 654 655 // temporarily drops SR_lock while doing wait with safepoint check 656 // (if we're a JavaThread - the WatcherThread can also call this) 657 // and increase delay with each retry 658 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 659 660 // check the actual thread state instead of what we saved above 661 if (thread_state() != _thread_in_native_trans) { 662 // the thread has transitioned to another thread state so 663 // try all the checks (except this one) one more time. 664 do_trans_retry = true; 665 break; 666 } 667 } // end retry loop 668 669 670 } 671 } while (do_trans_retry); 672 673 *bits |= 0x00000010; 674 return false; 675} 676 677// 678// Wait for an external suspend request to complete (or be cancelled). 679// Returns true if the thread is externally suspended and false otherwise. 680// 681bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 682 uint32_t *bits) { 683 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 684 false /* !called_by_wait */, bits); 685 686 // local flag copies to minimize SR_lock hold time 687 bool is_suspended; 688 bool pending; 689 uint32_t reset_bits; 690 691 // set a marker so is_ext_suspend_completed() knows we are the caller 692 *bits |= 0x00010000; 693 694 // We use reset_bits to reinitialize the bits value at the top of 695 // each retry loop. This allows the caller to make use of any 696 // unused bits for their own marking purposes. 697 reset_bits = *bits; 698 699 { 700 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 701 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 702 delay, bits); 703 pending = is_external_suspend(); 704 } 705 // must release SR_lock to allow suspension to complete 706 707 if (!pending) { 708 // A cancelled suspend request is the only false return from 709 // is_ext_suspend_completed() that keeps us from entering the 710 // retry loop. 711 *bits |= 0x00020000; 712 return false; 713 } 714 715 if (is_suspended) { 716 *bits |= 0x00040000; 717 return true; 718 } 719 720 for (int i = 1; i <= retries; i++) { 721 *bits = reset_bits; // reinit to only track last retry 722 723 // We used to do an "os::yield_all(i)" call here with the intention 724 // that yielding would increase on each retry. However, the parameter 725 // is ignored on Linux which means the yield didn't scale up. Waiting 726 // on the SR_lock below provides a much more predictable scale up for 727 // the delay. It also provides a simple/direct point to check for any 728 // safepoint requests from the VMThread 729 730 { 731 MutexLocker ml(SR_lock()); 732 // wait with safepoint check (if we're a JavaThread - the WatcherThread 733 // can also call this) and increase delay with each retry 734 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 735 736 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 737 delay, bits); 738 739 // It is possible for the external suspend request to be cancelled 740 // (by a resume) before the actual suspend operation is completed. 741 // Refresh our local copy to see if we still need to wait. 742 pending = is_external_suspend(); 743 } 744 745 if (!pending) { 746 // A cancelled suspend request is the only false return from 747 // is_ext_suspend_completed() that keeps us from staying in the 748 // retry loop. 749 *bits |= 0x00080000; 750 return false; 751 } 752 753 if (is_suspended) { 754 *bits |= 0x00100000; 755 return true; 756 } 757 } // end retry loop 758 759 // thread did not suspend after all our retries 760 *bits |= 0x00200000; 761 return false; 762} 763 764#ifndef PRODUCT 765void JavaThread::record_jump(address target, address instr, const char* file, int line) { 766 767 // This should not need to be atomic as the only way for simultaneous 768 // updates is via interrupts. Even then this should be rare or non-existant 769 // and we don't care that much anyway. 770 771 int index = _jmp_ring_index; 772 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 773 _jmp_ring[index]._target = (intptr_t) target; 774 _jmp_ring[index]._instruction = (intptr_t) instr; 775 _jmp_ring[index]._file = file; 776 _jmp_ring[index]._line = line; 777} 778#endif /* PRODUCT */ 779 780// Called by flat profiler 781// Callers have already called wait_for_ext_suspend_completion 782// The assertion for that is currently too complex to put here: 783bool JavaThread::profile_last_Java_frame(frame* _fr) { 784 bool gotframe = false; 785 // self suspension saves needed state. 786 if (has_last_Java_frame() && _anchor.walkable()) { 787 *_fr = pd_last_frame(); 788 gotframe = true; 789 } 790 return gotframe; 791} 792 793void Thread::interrupt(Thread* thread) { 794 trace("interrupt", thread); 795 debug_only(check_for_dangling_thread_pointer(thread);) 796 os::interrupt(thread); 797} 798 799bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 800 trace("is_interrupted", thread); 801 debug_only(check_for_dangling_thread_pointer(thread);) 802 // Note: If clear_interrupted==false, this simply fetches and 803 // returns the value of the field osthread()->interrupted(). 804 return os::is_interrupted(thread, clear_interrupted); 805} 806 807 808// GC Support 809bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 810 jint thread_parity = _oops_do_parity; 811 if (thread_parity != strong_roots_parity) { 812 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 813 if (res == thread_parity) { 814 return true; 815 } else { 816 guarantee(res == strong_roots_parity, "Or else what?"); 817 assert(SharedHeap::heap()->workers()->active_workers() > 0, 818 "Should only fail when parallel."); 819 return false; 820 } 821 } 822 assert(SharedHeap::heap()->workers()->active_workers() > 0, 823 "Should only fail when parallel."); 824 return false; 825} 826 827void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 828 active_handles()->oops_do(f); 829 // Do oop for ThreadShadow 830 f->do_oop((oop*)&_pending_exception); 831 handle_area()->oops_do(f); 832} 833 834void Thread::nmethods_do(CodeBlobClosure* cf) { 835 // no nmethods in a generic thread... 836} 837 838void Thread::metadata_do(void f(Metadata*)) { 839 if (metadata_handles() != NULL) { 840 for (int i = 0; i< metadata_handles()->length(); i++) { 841 f(metadata_handles()->at(i)); 842 } 843 } 844} 845 846void Thread::print_on(outputStream* st) const { 847 // get_priority assumes osthread initialized 848 if (osthread() != NULL) { 849 int os_prio; 850 if (os::get_native_priority(this, &os_prio) == OS_OK) { 851 st->print("os_prio=%d ", os_prio); 852 } 853 st->print("tid=" INTPTR_FORMAT " ", this); 854 osthread()->print_on(st); 855 } 856 debug_only(if (WizardMode) print_owned_locks_on(st);) 857} 858 859// Thread::print_on_error() is called by fatal error handler. Don't use 860// any lock or allocate memory. 861void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 862 if (is_VM_thread()) st->print("VMThread"); 863 else if (is_Compiler_thread()) st->print("CompilerThread"); 864 else if (is_Java_thread()) st->print("JavaThread"); 865 else if (is_GC_task_thread()) st->print("GCTaskThread"); 866 else if (is_Watcher_thread()) st->print("WatcherThread"); 867 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 868 else st->print("Thread"); 869 870 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 871 _stack_base - _stack_size, _stack_base); 872 873 if (osthread()) { 874 st->print(" [id=%d]", osthread()->thread_id()); 875 } 876} 877 878#ifdef ASSERT 879void Thread::print_owned_locks_on(outputStream* st) const { 880 Monitor *cur = _owned_locks; 881 if (cur == NULL) { 882 st->print(" (no locks) "); 883 } else { 884 st->print_cr(" Locks owned:"); 885 while(cur) { 886 cur->print_on(st); 887 cur = cur->next(); 888 } 889 } 890} 891 892static int ref_use_count = 0; 893 894bool Thread::owns_locks_but_compiled_lock() const { 895 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 896 if (cur != Compile_lock) return true; 897 } 898 return false; 899} 900 901 902#endif 903 904#ifndef PRODUCT 905 906// The flag: potential_vm_operation notifies if this particular safepoint state could potential 907// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 908// no threads which allow_vm_block's are held 909void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 910 // Check if current thread is allowed to block at a safepoint 911 if (!(_allow_safepoint_count == 0)) 912 fatal("Possible safepoint reached by thread that does not allow it"); 913 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 914 fatal("LEAF method calling lock?"); 915 } 916 917#ifdef ASSERT 918 if (potential_vm_operation && is_Java_thread() 919 && !Universe::is_bootstrapping()) { 920 // Make sure we do not hold any locks that the VM thread also uses. 921 // This could potentially lead to deadlocks 922 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 923 // Threads_lock is special, since the safepoint synchronization will not start before this is 924 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 925 // since it is used to transfer control between JavaThreads and the VMThread 926 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first! 927 if ( (cur->allow_vm_block() && 928 cur != Threads_lock && 929 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation 930 cur != VMOperationRequest_lock && 931 cur != VMOperationQueue_lock) || 932 cur->rank() == Mutex::special) { 933 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 934 } 935 } 936 } 937 938 if (GCALotAtAllSafepoints) { 939 // We could enter a safepoint here and thus have a gc 940 InterfaceSupport::check_gc_alot(); 941 } 942#endif 943} 944#endif 945 946bool Thread::is_in_stack(address adr) const { 947 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 948 address end = os::current_stack_pointer(); 949 // Allow non Java threads to call this without stack_base 950 if (_stack_base == NULL) return true; 951 if (stack_base() >= adr && adr >= end) return true; 952 953 return false; 954} 955 956 957bool Thread::is_in_usable_stack(address adr) const { 958 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 959 size_t usable_stack_size = _stack_size - stack_guard_size; 960 961 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 962} 963 964 965// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 966// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 967// used for compilation in the future. If that change is made, the need for these methods 968// should be revisited, and they should be removed if possible. 969 970bool Thread::is_lock_owned(address adr) const { 971 return on_local_stack(adr); 972} 973 974bool Thread::set_as_starting_thread() { 975 // NOTE: this must be called inside the main thread. 976 return os::create_main_thread((JavaThread*)this); 977} 978 979static void initialize_class(Symbol* class_name, TRAPS) { 980 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 981 InstanceKlass::cast(klass)->initialize(CHECK); 982} 983 984 985// Creates the initial ThreadGroup 986static Handle create_initial_thread_group(TRAPS) { 987 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 988 instanceKlassHandle klass (THREAD, k); 989 990 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 991 { 992 JavaValue result(T_VOID); 993 JavaCalls::call_special(&result, 994 system_instance, 995 klass, 996 vmSymbols::object_initializer_name(), 997 vmSymbols::void_method_signature(), 998 CHECK_NH); 999 } 1000 Universe::set_system_thread_group(system_instance()); 1001 1002 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 1003 { 1004 JavaValue result(T_VOID); 1005 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 1006 JavaCalls::call_special(&result, 1007 main_instance, 1008 klass, 1009 vmSymbols::object_initializer_name(), 1010 vmSymbols::threadgroup_string_void_signature(), 1011 system_instance, 1012 string, 1013 CHECK_NH); 1014 } 1015 return main_instance; 1016} 1017 1018// Creates the initial Thread 1019static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1020 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1021 instanceKlassHandle klass (THREAD, k); 1022 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1023 1024 java_lang_Thread::set_thread(thread_oop(), thread); 1025 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1026 thread->set_threadObj(thread_oop()); 1027 1028 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1029 1030 JavaValue result(T_VOID); 1031 JavaCalls::call_special(&result, thread_oop, 1032 klass, 1033 vmSymbols::object_initializer_name(), 1034 vmSymbols::threadgroup_string_void_signature(), 1035 thread_group, 1036 string, 1037 CHECK_NULL); 1038 return thread_oop(); 1039} 1040 1041static void call_initializeSystemClass(TRAPS) { 1042 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1043 instanceKlassHandle klass (THREAD, k); 1044 1045 JavaValue result(T_VOID); 1046 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1047 vmSymbols::void_method_signature(), CHECK); 1048} 1049 1050char java_runtime_name[128] = ""; 1051char java_runtime_version[128] = ""; 1052 1053// extract the JRE name from sun.misc.Version.java_runtime_name 1054static const char* get_java_runtime_name(TRAPS) { 1055 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1056 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1057 fieldDescriptor fd; 1058 bool found = k != NULL && 1059 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1060 vmSymbols::string_signature(), &fd); 1061 if (found) { 1062 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1063 if (name_oop == NULL) 1064 return NULL; 1065 const char* name = java_lang_String::as_utf8_string(name_oop, 1066 java_runtime_name, 1067 sizeof(java_runtime_name)); 1068 return name; 1069 } else { 1070 return NULL; 1071 } 1072} 1073 1074// extract the JRE version from sun.misc.Version.java_runtime_version 1075static const char* get_java_runtime_version(TRAPS) { 1076 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1077 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1078 fieldDescriptor fd; 1079 bool found = k != NULL && 1080 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1081 vmSymbols::string_signature(), &fd); 1082 if (found) { 1083 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1084 if (name_oop == NULL) 1085 return NULL; 1086 const char* name = java_lang_String::as_utf8_string(name_oop, 1087 java_runtime_version, 1088 sizeof(java_runtime_version)); 1089 return name; 1090 } else { 1091 return NULL; 1092 } 1093} 1094 1095// General purpose hook into Java code, run once when the VM is initialized. 1096// The Java library method itself may be changed independently from the VM. 1097static void call_postVMInitHook(TRAPS) { 1098 Klass* k = SystemDictionary::PostVMInitHook_klass(); 1099 instanceKlassHandle klass (THREAD, k); 1100 if (klass.not_null()) { 1101 JavaValue result(T_VOID); 1102 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1103 vmSymbols::void_method_signature(), 1104 CHECK); 1105 } 1106} 1107 1108static void reset_vm_info_property(TRAPS) { 1109 // the vm info string 1110 ResourceMark rm(THREAD); 1111 const char *vm_info = VM_Version::vm_info_string(); 1112 1113 // java.lang.System class 1114 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1115 instanceKlassHandle klass (THREAD, k); 1116 1117 // setProperty arguments 1118 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1119 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1120 1121 // return value 1122 JavaValue r(T_OBJECT); 1123 1124 // public static String setProperty(String key, String value); 1125 JavaCalls::call_static(&r, 1126 klass, 1127 vmSymbols::setProperty_name(), 1128 vmSymbols::string_string_string_signature(), 1129 key_str, 1130 value_str, 1131 CHECK); 1132} 1133 1134 1135void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1136 assert(thread_group.not_null(), "thread group should be specified"); 1137 assert(threadObj() == NULL, "should only create Java thread object once"); 1138 1139 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1140 instanceKlassHandle klass (THREAD, k); 1141 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1142 1143 java_lang_Thread::set_thread(thread_oop(), this); 1144 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1145 set_threadObj(thread_oop()); 1146 1147 JavaValue result(T_VOID); 1148 if (thread_name != NULL) { 1149 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1150 // Thread gets assigned specified name and null target 1151 JavaCalls::call_special(&result, 1152 thread_oop, 1153 klass, 1154 vmSymbols::object_initializer_name(), 1155 vmSymbols::threadgroup_string_void_signature(), 1156 thread_group, // Argument 1 1157 name, // Argument 2 1158 THREAD); 1159 } else { 1160 // Thread gets assigned name "Thread-nnn" and null target 1161 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1162 JavaCalls::call_special(&result, 1163 thread_oop, 1164 klass, 1165 vmSymbols::object_initializer_name(), 1166 vmSymbols::threadgroup_runnable_void_signature(), 1167 thread_group, // Argument 1 1168 Handle(), // Argument 2 1169 THREAD); 1170 } 1171 1172 1173 if (daemon) { 1174 java_lang_Thread::set_daemon(thread_oop()); 1175 } 1176 1177 if (HAS_PENDING_EXCEPTION) { 1178 return; 1179 } 1180 1181 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1182 Handle threadObj(this, this->threadObj()); 1183 1184 JavaCalls::call_special(&result, 1185 thread_group, 1186 group, 1187 vmSymbols::add_method_name(), 1188 vmSymbols::thread_void_signature(), 1189 threadObj, // Arg 1 1190 THREAD); 1191 1192 1193} 1194 1195// NamedThread -- non-JavaThread subclasses with multiple 1196// uniquely named instances should derive from this. 1197NamedThread::NamedThread() : Thread() { 1198 _name = NULL; 1199 _processed_thread = NULL; 1200} 1201 1202NamedThread::~NamedThread() { 1203 if (_name != NULL) { 1204 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1205 _name = NULL; 1206 } 1207} 1208 1209void NamedThread::set_name(const char* format, ...) { 1210 guarantee(_name == NULL, "Only get to set name once."); 1211 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1212 guarantee(_name != NULL, "alloc failure"); 1213 va_list ap; 1214 va_start(ap, format); 1215 jio_vsnprintf(_name, max_name_len, format, ap); 1216 va_end(ap); 1217} 1218 1219// ======= WatcherThread ======== 1220 1221// The watcher thread exists to simulate timer interrupts. It should 1222// be replaced by an abstraction over whatever native support for 1223// timer interrupts exists on the platform. 1224 1225WatcherThread* WatcherThread::_watcher_thread = NULL; 1226bool WatcherThread::_startable = false; 1227volatile bool WatcherThread::_should_terminate = false; 1228 1229WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1230 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1231 if (os::create_thread(this, os::watcher_thread)) { 1232 _watcher_thread = this; 1233 1234 // Set the watcher thread to the highest OS priority which should not be 1235 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1236 // is created. The only normal thread using this priority is the reference 1237 // handler thread, which runs for very short intervals only. 1238 // If the VMThread's priority is not lower than the WatcherThread profiling 1239 // will be inaccurate. 1240 os::set_priority(this, MaxPriority); 1241 if (!DisableStartThread) { 1242 os::start_thread(this); 1243 } 1244 } 1245} 1246 1247int WatcherThread::sleep() const { 1248 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1249 1250 // remaining will be zero if there are no tasks, 1251 // causing the WatcherThread to sleep until a task is 1252 // enrolled 1253 int remaining = PeriodicTask::time_to_wait(); 1254 int time_slept = 0; 1255 1256 // we expect this to timeout - we only ever get unparked when 1257 // we should terminate or when a new task has been enrolled 1258 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1259 1260 jlong time_before_loop = os::javaTimeNanos(); 1261 1262 for (;;) { 1263 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1264 jlong now = os::javaTimeNanos(); 1265 1266 if (remaining == 0) { 1267 // if we didn't have any tasks we could have waited for a long time 1268 // consider the time_slept zero and reset time_before_loop 1269 time_slept = 0; 1270 time_before_loop = now; 1271 } else { 1272 // need to recalulate since we might have new tasks in _tasks 1273 time_slept = (int) ((now - time_before_loop) / 1000000); 1274 } 1275 1276 // Change to task list or spurious wakeup of some kind 1277 if (timedout || _should_terminate) { 1278 break; 1279 } 1280 1281 remaining = PeriodicTask::time_to_wait(); 1282 if (remaining == 0) { 1283 // Last task was just disenrolled so loop around and wait until 1284 // another task gets enrolled 1285 continue; 1286 } 1287 1288 remaining -= time_slept; 1289 if (remaining <= 0) 1290 break; 1291 } 1292 1293 return time_slept; 1294} 1295 1296void WatcherThread::run() { 1297 assert(this == watcher_thread(), "just checking"); 1298 1299 this->record_stack_base_and_size(); 1300 this->initialize_thread_local_storage(); 1301 this->set_active_handles(JNIHandleBlock::allocate_block()); 1302 while(!_should_terminate) { 1303 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1304 assert(watcher_thread() == this, "thread consistency check"); 1305 1306 // Calculate how long it'll be until the next PeriodicTask work 1307 // should be done, and sleep that amount of time. 1308 int time_waited = sleep(); 1309 1310 if (is_error_reported()) { 1311 // A fatal error has happened, the error handler(VMError::report_and_die) 1312 // should abort JVM after creating an error log file. However in some 1313 // rare cases, the error handler itself might deadlock. Here we try to 1314 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1315 // 1316 // This code is in WatcherThread because WatcherThread wakes up 1317 // periodically so the fatal error handler doesn't need to do anything; 1318 // also because the WatcherThread is less likely to crash than other 1319 // threads. 1320 1321 for (;;) { 1322 if (!ShowMessageBoxOnError 1323 && (OnError == NULL || OnError[0] == '\0') 1324 && Arguments::abort_hook() == NULL) { 1325 os::sleep(this, 2 * 60 * 1000, false); 1326 fdStream err(defaultStream::output_fd()); 1327 err.print_raw_cr("# [ timer expired, abort... ]"); 1328 // skip atexit/vm_exit/vm_abort hooks 1329 os::die(); 1330 } 1331 1332 // Wake up 5 seconds later, the fatal handler may reset OnError or 1333 // ShowMessageBoxOnError when it is ready to abort. 1334 os::sleep(this, 5 * 1000, false); 1335 } 1336 } 1337 1338 PeriodicTask::real_time_tick(time_waited); 1339 } 1340 1341 // Signal that it is terminated 1342 { 1343 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1344 _watcher_thread = NULL; 1345 Terminator_lock->notify(); 1346 } 1347 1348 // Thread destructor usually does this.. 1349 ThreadLocalStorage::set_thread(NULL); 1350} 1351 1352void WatcherThread::start() { 1353 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1354 1355 if (watcher_thread() == NULL && _startable) { 1356 _should_terminate = false; 1357 // Create the single instance of WatcherThread 1358 new WatcherThread(); 1359 } 1360} 1361 1362void WatcherThread::make_startable() { 1363 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1364 _startable = true; 1365} 1366 1367void WatcherThread::stop() { 1368 { 1369 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1370 _should_terminate = true; 1371 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1372 1373 WatcherThread* watcher = watcher_thread(); 1374 if (watcher != NULL) 1375 watcher->unpark(); 1376 } 1377 1378 // it is ok to take late safepoints here, if needed 1379 MutexLocker mu(Terminator_lock); 1380 1381 while(watcher_thread() != NULL) { 1382 // This wait should make safepoint checks, wait without a timeout, 1383 // and wait as a suspend-equivalent condition. 1384 // 1385 // Note: If the FlatProfiler is running, then this thread is waiting 1386 // for the WatcherThread to terminate and the WatcherThread, via the 1387 // FlatProfiler task, is waiting for the external suspend request on 1388 // this thread to complete. wait_for_ext_suspend_completion() will 1389 // eventually timeout, but that takes time. Making this wait a 1390 // suspend-equivalent condition solves that timeout problem. 1391 // 1392 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1393 Mutex::_as_suspend_equivalent_flag); 1394 } 1395} 1396 1397void WatcherThread::unpark() { 1398 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1399 PeriodicTask_lock->notify(); 1400} 1401 1402void WatcherThread::print_on(outputStream* st) const { 1403 st->print("\"%s\" ", name()); 1404 Thread::print_on(st); 1405 st->cr(); 1406} 1407 1408// ======= JavaThread ======== 1409 1410// A JavaThread is a normal Java thread 1411 1412void JavaThread::initialize() { 1413 // Initialize fields 1414 1415 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1416 set_claimed_par_id(-1); 1417 1418 set_saved_exception_pc(NULL); 1419 set_threadObj(NULL); 1420 _anchor.clear(); 1421 set_entry_point(NULL); 1422 set_jni_functions(jni_functions()); 1423 set_callee_target(NULL); 1424 set_vm_result(NULL); 1425 set_vm_result_2(NULL); 1426 set_vframe_array_head(NULL); 1427 set_vframe_array_last(NULL); 1428 set_deferred_locals(NULL); 1429 set_deopt_mark(NULL); 1430 set_deopt_nmethod(NULL); 1431 clear_must_deopt_id(); 1432 set_monitor_chunks(NULL); 1433 set_next(NULL); 1434 set_thread_state(_thread_new); 1435#if INCLUDE_NMT 1436 set_recorder(NULL); 1437#endif 1438 _terminated = _not_terminated; 1439 _privileged_stack_top = NULL; 1440 _array_for_gc = NULL; 1441 _suspend_equivalent = false; 1442 _in_deopt_handler = 0; 1443 _doing_unsafe_access = false; 1444 _stack_guard_state = stack_guard_unused; 1445 _exception_oop = NULL; 1446 _exception_pc = 0; 1447 _exception_handler_pc = 0; 1448 _is_method_handle_return = 0; 1449 _jvmti_thread_state= NULL; 1450 _should_post_on_exceptions_flag = JNI_FALSE; 1451 _jvmti_get_loaded_classes_closure = NULL; 1452 _interp_only_mode = 0; 1453 _special_runtime_exit_condition = _no_async_condition; 1454 _pending_async_exception = NULL; 1455 _is_compiling = false; 1456 _thread_stat = NULL; 1457 _thread_stat = new ThreadStatistics(); 1458 _blocked_on_compilation = false; 1459 _jni_active_critical = 0; 1460 _do_not_unlock_if_synchronized = false; 1461 _cached_monitor_info = NULL; 1462 _parker = Parker::Allocate(this) ; 1463 1464#ifndef PRODUCT 1465 _jmp_ring_index = 0; 1466 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1467 record_jump(NULL, NULL, NULL, 0); 1468 } 1469#endif /* PRODUCT */ 1470 1471 set_thread_profiler(NULL); 1472 if (FlatProfiler::is_active()) { 1473 // This is where we would decide to either give each thread it's own profiler 1474 // or use one global one from FlatProfiler, 1475 // or up to some count of the number of profiled threads, etc. 1476 ThreadProfiler* pp = new ThreadProfiler(); 1477 pp->engage(); 1478 set_thread_profiler(pp); 1479 } 1480 1481 // Setup safepoint state info for this thread 1482 ThreadSafepointState::create(this); 1483 1484 debug_only(_java_call_counter = 0); 1485 1486 // JVMTI PopFrame support 1487 _popframe_condition = popframe_inactive; 1488 _popframe_preserved_args = NULL; 1489 _popframe_preserved_args_size = 0; 1490 1491 pd_initialize(); 1492} 1493 1494#if INCLUDE_ALL_GCS 1495SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1496DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1497#endif // INCLUDE_ALL_GCS 1498 1499JavaThread::JavaThread(bool is_attaching_via_jni) : 1500 Thread() 1501#if INCLUDE_ALL_GCS 1502 , _satb_mark_queue(&_satb_mark_queue_set), 1503 _dirty_card_queue(&_dirty_card_queue_set) 1504#endif // INCLUDE_ALL_GCS 1505{ 1506 initialize(); 1507 if (is_attaching_via_jni) { 1508 _jni_attach_state = _attaching_via_jni; 1509 } else { 1510 _jni_attach_state = _not_attaching_via_jni; 1511 } 1512 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1513 _safepoint_visible = false; 1514} 1515 1516bool JavaThread::reguard_stack(address cur_sp) { 1517 if (_stack_guard_state != stack_guard_yellow_disabled) { 1518 return true; // Stack already guarded or guard pages not needed. 1519 } 1520 1521 if (register_stack_overflow()) { 1522 // For those architectures which have separate register and 1523 // memory stacks, we must check the register stack to see if 1524 // it has overflowed. 1525 return false; 1526 } 1527 1528 // Java code never executes within the yellow zone: the latter is only 1529 // there to provoke an exception during stack banging. If java code 1530 // is executing there, either StackShadowPages should be larger, or 1531 // some exception code in c1, c2 or the interpreter isn't unwinding 1532 // when it should. 1533 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1534 1535 enable_stack_yellow_zone(); 1536 return true; 1537} 1538 1539bool JavaThread::reguard_stack(void) { 1540 return reguard_stack(os::current_stack_pointer()); 1541} 1542 1543 1544void JavaThread::block_if_vm_exited() { 1545 if (_terminated == _vm_exited) { 1546 // _vm_exited is set at safepoint, and Threads_lock is never released 1547 // we will block here forever 1548 Threads_lock->lock_without_safepoint_check(); 1549 ShouldNotReachHere(); 1550 } 1551} 1552 1553 1554// Remove this ifdef when C1 is ported to the compiler interface. 1555static void compiler_thread_entry(JavaThread* thread, TRAPS); 1556 1557JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1558 Thread() 1559#if INCLUDE_ALL_GCS 1560 , _satb_mark_queue(&_satb_mark_queue_set), 1561 _dirty_card_queue(&_dirty_card_queue_set) 1562#endif // INCLUDE_ALL_GCS 1563{ 1564 if (TraceThreadEvents) { 1565 tty->print_cr("creating thread %p", this); 1566 } 1567 initialize(); 1568 _jni_attach_state = _not_attaching_via_jni; 1569 set_entry_point(entry_point); 1570 // Create the native thread itself. 1571 // %note runtime_23 1572 os::ThreadType thr_type = os::java_thread; 1573 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1574 os::java_thread; 1575 os::create_thread(this, thr_type, stack_sz); 1576 _safepoint_visible = false; 1577 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1578 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1579 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1580 // the exception consists of creating the exception object & initializing it, initialization 1581 // will leave the VM via a JavaCall and then all locks must be unlocked). 1582 // 1583 // The thread is still suspended when we reach here. Thread must be explicit started 1584 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1585 // by calling Threads:add. The reason why this is not done here, is because the thread 1586 // object must be fully initialized (take a look at JVM_Start) 1587} 1588 1589JavaThread::~JavaThread() { 1590 if (TraceThreadEvents) { 1591 tty->print_cr("terminate thread %p", this); 1592 } 1593 1594 // By now, this thread should already be invisible to safepoint, 1595 // and its per-thread recorder also collected. 1596 assert(!is_safepoint_visible(), "wrong state"); 1597#if INCLUDE_NMT 1598 assert(get_recorder() == NULL, "Already collected"); 1599#endif // INCLUDE_NMT 1600 1601 // JSR166 -- return the parker to the free list 1602 Parker::Release(_parker); 1603 _parker = NULL ; 1604 1605 // Free any remaining previous UnrollBlock 1606 vframeArray* old_array = vframe_array_last(); 1607 1608 if (old_array != NULL) { 1609 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1610 old_array->set_unroll_block(NULL); 1611 delete old_info; 1612 delete old_array; 1613 } 1614 1615 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1616 if (deferred != NULL) { 1617 // This can only happen if thread is destroyed before deoptimization occurs. 1618 assert(deferred->length() != 0, "empty array!"); 1619 do { 1620 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1621 deferred->remove_at(0); 1622 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1623 delete dlv; 1624 } while (deferred->length() != 0); 1625 delete deferred; 1626 } 1627 1628 // All Java related clean up happens in exit 1629 ThreadSafepointState::destroy(this); 1630 if (_thread_profiler != NULL) delete _thread_profiler; 1631 if (_thread_stat != NULL) delete _thread_stat; 1632} 1633 1634 1635// The first routine called by a new Java thread 1636void JavaThread::run() { 1637 // initialize thread-local alloc buffer related fields 1638 this->initialize_tlab(); 1639 1640 // used to test validitity of stack trace backs 1641 this->record_base_of_stack_pointer(); 1642 1643 // Record real stack base and size. 1644 this->record_stack_base_and_size(); 1645 1646 // Initialize thread local storage; set before calling MutexLocker 1647 this->initialize_thread_local_storage(); 1648 1649 this->create_stack_guard_pages(); 1650 1651 this->cache_global_variables(); 1652 1653 // Thread is now sufficient initialized to be handled by the safepoint code as being 1654 // in the VM. Change thread state from _thread_new to _thread_in_vm 1655 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1656 1657 assert(JavaThread::current() == this, "sanity check"); 1658 assert(!Thread::current()->owns_locks(), "sanity check"); 1659 1660 DTRACE_THREAD_PROBE(start, this); 1661 1662 // This operation might block. We call that after all safepoint checks for a new thread has 1663 // been completed. 1664 this->set_active_handles(JNIHandleBlock::allocate_block()); 1665 1666 if (JvmtiExport::should_post_thread_life()) { 1667 JvmtiExport::post_thread_start(this); 1668 } 1669 1670 EventThreadStart event; 1671 if (event.should_commit()) { 1672 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1673 event.commit(); 1674 } 1675 1676 // We call another function to do the rest so we are sure that the stack addresses used 1677 // from there will be lower than the stack base just computed 1678 thread_main_inner(); 1679 1680 // Note, thread is no longer valid at this point! 1681} 1682 1683 1684void JavaThread::thread_main_inner() { 1685 assert(JavaThread::current() == this, "sanity check"); 1686 assert(this->threadObj() != NULL, "just checking"); 1687 1688 // Execute thread entry point unless this thread has a pending exception 1689 // or has been stopped before starting. 1690 // Note: Due to JVM_StopThread we can have pending exceptions already! 1691 if (!this->has_pending_exception() && 1692 !java_lang_Thread::is_stillborn(this->threadObj())) { 1693 { 1694 ResourceMark rm(this); 1695 this->set_native_thread_name(this->get_thread_name()); 1696 } 1697 HandleMark hm(this); 1698 this->entry_point()(this, this); 1699 } 1700 1701 DTRACE_THREAD_PROBE(stop, this); 1702 1703 this->exit(false); 1704 delete this; 1705} 1706 1707 1708static void ensure_join(JavaThread* thread) { 1709 // We do not need to grap the Threads_lock, since we are operating on ourself. 1710 Handle threadObj(thread, thread->threadObj()); 1711 assert(threadObj.not_null(), "java thread object must exist"); 1712 ObjectLocker lock(threadObj, thread); 1713 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1714 thread->clear_pending_exception(); 1715 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1716 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1717 // Clear the native thread instance - this makes isAlive return false and allows the join() 1718 // to complete once we've done the notify_all below 1719 java_lang_Thread::set_thread(threadObj(), NULL); 1720 lock.notify_all(thread); 1721 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1722 thread->clear_pending_exception(); 1723} 1724 1725 1726// For any new cleanup additions, please check to see if they need to be applied to 1727// cleanup_failed_attach_current_thread as well. 1728void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1729 assert(this == JavaThread::current(), "thread consistency check"); 1730 1731 HandleMark hm(this); 1732 Handle uncaught_exception(this, this->pending_exception()); 1733 this->clear_pending_exception(); 1734 Handle threadObj(this, this->threadObj()); 1735 assert(threadObj.not_null(), "Java thread object should be created"); 1736 1737 if (get_thread_profiler() != NULL) { 1738 get_thread_profiler()->disengage(); 1739 ResourceMark rm; 1740 get_thread_profiler()->print(get_thread_name()); 1741 } 1742 1743 1744 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1745 { 1746 EXCEPTION_MARK; 1747 1748 CLEAR_PENDING_EXCEPTION; 1749 } 1750 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1751 // has to be fixed by a runtime query method 1752 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1753 // JSR-166: change call from from ThreadGroup.uncaughtException to 1754 // java.lang.Thread.dispatchUncaughtException 1755 if (uncaught_exception.not_null()) { 1756 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1757 { 1758 EXCEPTION_MARK; 1759 // Check if the method Thread.dispatchUncaughtException() exists. If so 1760 // call it. Otherwise we have an older library without the JSR-166 changes, 1761 // so call ThreadGroup.uncaughtException() 1762 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1763 CallInfo callinfo; 1764 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1765 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1766 vmSymbols::dispatchUncaughtException_name(), 1767 vmSymbols::throwable_void_signature(), 1768 KlassHandle(), false, false, THREAD); 1769 CLEAR_PENDING_EXCEPTION; 1770 methodHandle method = callinfo.selected_method(); 1771 if (method.not_null()) { 1772 JavaValue result(T_VOID); 1773 JavaCalls::call_virtual(&result, 1774 threadObj, thread_klass, 1775 vmSymbols::dispatchUncaughtException_name(), 1776 vmSymbols::throwable_void_signature(), 1777 uncaught_exception, 1778 THREAD); 1779 } else { 1780 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1781 JavaValue result(T_VOID); 1782 JavaCalls::call_virtual(&result, 1783 group, thread_group, 1784 vmSymbols::uncaughtException_name(), 1785 vmSymbols::thread_throwable_void_signature(), 1786 threadObj, // Arg 1 1787 uncaught_exception, // Arg 2 1788 THREAD); 1789 } 1790 if (HAS_PENDING_EXCEPTION) { 1791 ResourceMark rm(this); 1792 jio_fprintf(defaultStream::error_stream(), 1793 "\nException: %s thrown from the UncaughtExceptionHandler" 1794 " in thread \"%s\"\n", 1795 pending_exception()->klass()->external_name(), 1796 get_thread_name()); 1797 CLEAR_PENDING_EXCEPTION; 1798 } 1799 } 1800 } 1801 1802 // Called before the java thread exit since we want to read info 1803 // from java_lang_Thread object 1804 EventThreadEnd event; 1805 if (event.should_commit()) { 1806 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1807 event.commit(); 1808 } 1809 1810 // Call after last event on thread 1811 EVENT_THREAD_EXIT(this); 1812 1813 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1814 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1815 // is deprecated anyhow. 1816 { int count = 3; 1817 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1818 EXCEPTION_MARK; 1819 JavaValue result(T_VOID); 1820 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1821 JavaCalls::call_virtual(&result, 1822 threadObj, thread_klass, 1823 vmSymbols::exit_method_name(), 1824 vmSymbols::void_method_signature(), 1825 THREAD); 1826 CLEAR_PENDING_EXCEPTION; 1827 } 1828 } 1829 1830 // notify JVMTI 1831 if (JvmtiExport::should_post_thread_life()) { 1832 JvmtiExport::post_thread_end(this); 1833 } 1834 1835 // We have notified the agents that we are exiting, before we go on, 1836 // we must check for a pending external suspend request and honor it 1837 // in order to not surprise the thread that made the suspend request. 1838 while (true) { 1839 { 1840 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1841 if (!is_external_suspend()) { 1842 set_terminated(_thread_exiting); 1843 ThreadService::current_thread_exiting(this); 1844 break; 1845 } 1846 // Implied else: 1847 // Things get a little tricky here. We have a pending external 1848 // suspend request, but we are holding the SR_lock so we 1849 // can't just self-suspend. So we temporarily drop the lock 1850 // and then self-suspend. 1851 } 1852 1853 ThreadBlockInVM tbivm(this); 1854 java_suspend_self(); 1855 1856 // We're done with this suspend request, but we have to loop around 1857 // and check again. Eventually we will get SR_lock without a pending 1858 // external suspend request and will be able to mark ourselves as 1859 // exiting. 1860 } 1861 // no more external suspends are allowed at this point 1862 } else { 1863 // before_exit() has already posted JVMTI THREAD_END events 1864 } 1865 1866 // Notify waiters on thread object. This has to be done after exit() is called 1867 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1868 // group should have the destroyed bit set before waiters are notified). 1869 ensure_join(this); 1870 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1871 1872 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1873 // held by this thread must be released. A detach operation must only 1874 // get here if there are no Java frames on the stack. Therefore, any 1875 // owned monitors at this point MUST be JNI-acquired monitors which are 1876 // pre-inflated and in the monitor cache. 1877 // 1878 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1879 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1880 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1881 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1882 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1883 } 1884 1885 // These things needs to be done while we are still a Java Thread. Make sure that thread 1886 // is in a consistent state, in case GC happens 1887 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1888 1889 if (active_handles() != NULL) { 1890 JNIHandleBlock* block = active_handles(); 1891 set_active_handles(NULL); 1892 JNIHandleBlock::release_block(block); 1893 } 1894 1895 if (free_handle_block() != NULL) { 1896 JNIHandleBlock* block = free_handle_block(); 1897 set_free_handle_block(NULL); 1898 JNIHandleBlock::release_block(block); 1899 } 1900 1901 // These have to be removed while this is still a valid thread. 1902 remove_stack_guard_pages(); 1903 1904 if (UseTLAB) { 1905 tlab().make_parsable(true); // retire TLAB 1906 } 1907 1908 if (JvmtiEnv::environments_might_exist()) { 1909 JvmtiExport::cleanup_thread(this); 1910 } 1911 1912 // We must flush any deferred card marks before removing a thread from 1913 // the list of active threads. 1914 Universe::heap()->flush_deferred_store_barrier(this); 1915 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1916 1917#if INCLUDE_ALL_GCS 1918 // We must flush the G1-related buffers before removing a thread 1919 // from the list of active threads. We must do this after any deferred 1920 // card marks have been flushed (above) so that any entries that are 1921 // added to the thread's dirty card queue as a result are not lost. 1922 if (UseG1GC) { 1923 flush_barrier_queues(); 1924 } 1925#endif // INCLUDE_ALL_GCS 1926 1927 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1928 Threads::remove(this); 1929} 1930 1931#if INCLUDE_ALL_GCS 1932// Flush G1-related queues. 1933void JavaThread::flush_barrier_queues() { 1934 satb_mark_queue().flush(); 1935 dirty_card_queue().flush(); 1936} 1937 1938void JavaThread::initialize_queues() { 1939 assert(!SafepointSynchronize::is_at_safepoint(), 1940 "we should not be at a safepoint"); 1941 1942 ObjPtrQueue& satb_queue = satb_mark_queue(); 1943 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1944 // The SATB queue should have been constructed with its active 1945 // field set to false. 1946 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1947 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1948 // If we are creating the thread during a marking cycle, we should 1949 // set the active field of the SATB queue to true. 1950 if (satb_queue_set.is_active()) { 1951 satb_queue.set_active(true); 1952 } 1953 1954 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1955 // The dirty card queue should have been constructed with its 1956 // active field set to true. 1957 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1958} 1959#endif // INCLUDE_ALL_GCS 1960 1961void JavaThread::cleanup_failed_attach_current_thread() { 1962 if (get_thread_profiler() != NULL) { 1963 get_thread_profiler()->disengage(); 1964 ResourceMark rm; 1965 get_thread_profiler()->print(get_thread_name()); 1966 } 1967 1968 if (active_handles() != NULL) { 1969 JNIHandleBlock* block = active_handles(); 1970 set_active_handles(NULL); 1971 JNIHandleBlock::release_block(block); 1972 } 1973 1974 if (free_handle_block() != NULL) { 1975 JNIHandleBlock* block = free_handle_block(); 1976 set_free_handle_block(NULL); 1977 JNIHandleBlock::release_block(block); 1978 } 1979 1980 // These have to be removed while this is still a valid thread. 1981 remove_stack_guard_pages(); 1982 1983 if (UseTLAB) { 1984 tlab().make_parsable(true); // retire TLAB, if any 1985 } 1986 1987#if INCLUDE_ALL_GCS 1988 if (UseG1GC) { 1989 flush_barrier_queues(); 1990 } 1991#endif // INCLUDE_ALL_GCS 1992 1993 Threads::remove(this); 1994 delete this; 1995} 1996 1997 1998 1999 2000JavaThread* JavaThread::active() { 2001 Thread* thread = ThreadLocalStorage::thread(); 2002 assert(thread != NULL, "just checking"); 2003 if (thread->is_Java_thread()) { 2004 return (JavaThread*) thread; 2005 } else { 2006 assert(thread->is_VM_thread(), "this must be a vm thread"); 2007 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2008 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2009 assert(ret->is_Java_thread(), "must be a Java thread"); 2010 return ret; 2011 } 2012} 2013 2014bool JavaThread::is_lock_owned(address adr) const { 2015 if (Thread::is_lock_owned(adr)) return true; 2016 2017 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2018 if (chunk->contains(adr)) return true; 2019 } 2020 2021 return false; 2022} 2023 2024 2025void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2026 chunk->set_next(monitor_chunks()); 2027 set_monitor_chunks(chunk); 2028} 2029 2030void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2031 guarantee(monitor_chunks() != NULL, "must be non empty"); 2032 if (monitor_chunks() == chunk) { 2033 set_monitor_chunks(chunk->next()); 2034 } else { 2035 MonitorChunk* prev = monitor_chunks(); 2036 while (prev->next() != chunk) prev = prev->next(); 2037 prev->set_next(chunk->next()); 2038 } 2039} 2040 2041// JVM support. 2042 2043// Note: this function shouldn't block if it's called in 2044// _thread_in_native_trans state (such as from 2045// check_special_condition_for_native_trans()). 2046void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2047 2048 if (has_last_Java_frame() && has_async_condition()) { 2049 // If we are at a polling page safepoint (not a poll return) 2050 // then we must defer async exception because live registers 2051 // will be clobbered by the exception path. Poll return is 2052 // ok because the call we a returning from already collides 2053 // with exception handling registers and so there is no issue. 2054 // (The exception handling path kills call result registers but 2055 // this is ok since the exception kills the result anyway). 2056 2057 if (is_at_poll_safepoint()) { 2058 // if the code we are returning to has deoptimized we must defer 2059 // the exception otherwise live registers get clobbered on the 2060 // exception path before deoptimization is able to retrieve them. 2061 // 2062 RegisterMap map(this, false); 2063 frame caller_fr = last_frame().sender(&map); 2064 assert(caller_fr.is_compiled_frame(), "what?"); 2065 if (caller_fr.is_deoptimized_frame()) { 2066 if (TraceExceptions) { 2067 ResourceMark rm; 2068 tty->print_cr("deferred async exception at compiled safepoint"); 2069 } 2070 return; 2071 } 2072 } 2073 } 2074 2075 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2076 if (condition == _no_async_condition) { 2077 // Conditions have changed since has_special_runtime_exit_condition() 2078 // was called: 2079 // - if we were here only because of an external suspend request, 2080 // then that was taken care of above (or cancelled) so we are done 2081 // - if we were here because of another async request, then it has 2082 // been cleared between the has_special_runtime_exit_condition() 2083 // and now so again we are done 2084 return; 2085 } 2086 2087 // Check for pending async. exception 2088 if (_pending_async_exception != NULL) { 2089 // Only overwrite an already pending exception, if it is not a threadDeath. 2090 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2091 2092 // We cannot call Exceptions::_throw(...) here because we cannot block 2093 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2094 2095 if (TraceExceptions) { 2096 ResourceMark rm; 2097 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2098 if (has_last_Java_frame() ) { 2099 frame f = last_frame(); 2100 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2101 } 2102 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2103 } 2104 _pending_async_exception = NULL; 2105 clear_has_async_exception(); 2106 } 2107 } 2108 2109 if (check_unsafe_error && 2110 condition == _async_unsafe_access_error && !has_pending_exception()) { 2111 condition = _no_async_condition; // done 2112 switch (thread_state()) { 2113 case _thread_in_vm: 2114 { 2115 JavaThread* THREAD = this; 2116 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2117 } 2118 case _thread_in_native: 2119 { 2120 ThreadInVMfromNative tiv(this); 2121 JavaThread* THREAD = this; 2122 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2123 } 2124 case _thread_in_Java: 2125 { 2126 ThreadInVMfromJava tiv(this); 2127 JavaThread* THREAD = this; 2128 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2129 } 2130 default: 2131 ShouldNotReachHere(); 2132 } 2133 } 2134 2135 assert(condition == _no_async_condition || has_pending_exception() || 2136 (!check_unsafe_error && condition == _async_unsafe_access_error), 2137 "must have handled the async condition, if no exception"); 2138} 2139 2140void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2141 // 2142 // Check for pending external suspend. Internal suspend requests do 2143 // not use handle_special_runtime_exit_condition(). 2144 // If JNIEnv proxies are allowed, don't self-suspend if the target 2145 // thread is not the current thread. In older versions of jdbx, jdbx 2146 // threads could call into the VM with another thread's JNIEnv so we 2147 // can be here operating on behalf of a suspended thread (4432884). 2148 bool do_self_suspend = is_external_suspend_with_lock(); 2149 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2150 // 2151 // Because thread is external suspended the safepoint code will count 2152 // thread as at a safepoint. This can be odd because we can be here 2153 // as _thread_in_Java which would normally transition to _thread_blocked 2154 // at a safepoint. We would like to mark the thread as _thread_blocked 2155 // before calling java_suspend_self like all other callers of it but 2156 // we must then observe proper safepoint protocol. (We can't leave 2157 // _thread_blocked with a safepoint in progress). However we can be 2158 // here as _thread_in_native_trans so we can't use a normal transition 2159 // constructor/destructor pair because they assert on that type of 2160 // transition. We could do something like: 2161 // 2162 // JavaThreadState state = thread_state(); 2163 // set_thread_state(_thread_in_vm); 2164 // { 2165 // ThreadBlockInVM tbivm(this); 2166 // java_suspend_self() 2167 // } 2168 // set_thread_state(_thread_in_vm_trans); 2169 // if (safepoint) block; 2170 // set_thread_state(state); 2171 // 2172 // but that is pretty messy. Instead we just go with the way the 2173 // code has worked before and note that this is the only path to 2174 // java_suspend_self that doesn't put the thread in _thread_blocked 2175 // mode. 2176 2177 frame_anchor()->make_walkable(this); 2178 java_suspend_self(); 2179 2180 // We might be here for reasons in addition to the self-suspend request 2181 // so check for other async requests. 2182 } 2183 2184 if (check_asyncs) { 2185 check_and_handle_async_exceptions(); 2186 } 2187} 2188 2189void JavaThread::send_thread_stop(oop java_throwable) { 2190 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2191 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2192 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2193 2194 // Do not throw asynchronous exceptions against the compiler thread 2195 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2196 if (is_Compiler_thread()) return; 2197 2198 { 2199 // Actually throw the Throwable against the target Thread - however 2200 // only if there is no thread death exception installed already. 2201 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2202 // If the topmost frame is a runtime stub, then we are calling into 2203 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2204 // must deoptimize the caller before continuing, as the compiled exception handler table 2205 // may not be valid 2206 if (has_last_Java_frame()) { 2207 frame f = last_frame(); 2208 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2209 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2210 RegisterMap reg_map(this, UseBiasedLocking); 2211 frame compiled_frame = f.sender(®_map); 2212 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2213 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2214 } 2215 } 2216 } 2217 2218 // Set async. pending exception in thread. 2219 set_pending_async_exception(java_throwable); 2220 2221 if (TraceExceptions) { 2222 ResourceMark rm; 2223 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2224 } 2225 // for AbortVMOnException flag 2226 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2227 } 2228 } 2229 2230 2231 // Interrupt thread so it will wake up from a potential wait() 2232 Thread::interrupt(this); 2233} 2234 2235// External suspension mechanism. 2236// 2237// Tell the VM to suspend a thread when ever it knows that it does not hold on 2238// to any VM_locks and it is at a transition 2239// Self-suspension will happen on the transition out of the vm. 2240// Catch "this" coming in from JNIEnv pointers when the thread has been freed 2241// 2242// Guarantees on return: 2243// + Target thread will not execute any new bytecode (that's why we need to 2244// force a safepoint) 2245// + Target thread will not enter any new monitors 2246// 2247void JavaThread::java_suspend() { 2248 { MutexLocker mu(Threads_lock); 2249 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2250 return; 2251 } 2252 } 2253 2254 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2255 if (!is_external_suspend()) { 2256 // a racing resume has cancelled us; bail out now 2257 return; 2258 } 2259 2260 // suspend is done 2261 uint32_t debug_bits = 0; 2262 // Warning: is_ext_suspend_completed() may temporarily drop the 2263 // SR_lock to allow the thread to reach a stable thread state if 2264 // it is currently in a transient thread state. 2265 if (is_ext_suspend_completed(false /* !called_by_wait */, 2266 SuspendRetryDelay, &debug_bits) ) { 2267 return; 2268 } 2269 } 2270 2271 VM_ForceSafepoint vm_suspend; 2272 VMThread::execute(&vm_suspend); 2273} 2274 2275// Part II of external suspension. 2276// A JavaThread self suspends when it detects a pending external suspend 2277// request. This is usually on transitions. It is also done in places 2278// where continuing to the next transition would surprise the caller, 2279// e.g., monitor entry. 2280// 2281// Returns the number of times that the thread self-suspended. 2282// 2283// Note: DO NOT call java_suspend_self() when you just want to block current 2284// thread. java_suspend_self() is the second stage of cooperative 2285// suspension for external suspend requests and should only be used 2286// to complete an external suspend request. 2287// 2288int JavaThread::java_suspend_self() { 2289 int ret = 0; 2290 2291 // we are in the process of exiting so don't suspend 2292 if (is_exiting()) { 2293 clear_external_suspend(); 2294 return ret; 2295 } 2296 2297 assert(_anchor.walkable() || 2298 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2299 "must have walkable stack"); 2300 2301 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2302 2303 assert(!this->is_ext_suspended(), 2304 "a thread trying to self-suspend should not already be suspended"); 2305 2306 if (this->is_suspend_equivalent()) { 2307 // If we are self-suspending as a result of the lifting of a 2308 // suspend equivalent condition, then the suspend_equivalent 2309 // flag is not cleared until we set the ext_suspended flag so 2310 // that wait_for_ext_suspend_completion() returns consistent 2311 // results. 2312 this->clear_suspend_equivalent(); 2313 } 2314 2315 // A racing resume may have cancelled us before we grabbed SR_lock 2316 // above. Or another external suspend request could be waiting for us 2317 // by the time we return from SR_lock()->wait(). The thread 2318 // that requested the suspension may already be trying to walk our 2319 // stack and if we return now, we can change the stack out from under 2320 // it. This would be a "bad thing (TM)" and cause the stack walker 2321 // to crash. We stay self-suspended until there are no more pending 2322 // external suspend requests. 2323 while (is_external_suspend()) { 2324 ret++; 2325 this->set_ext_suspended(); 2326 2327 // _ext_suspended flag is cleared by java_resume() 2328 while (is_ext_suspended()) { 2329 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2330 } 2331 } 2332 2333 return ret; 2334} 2335 2336#ifdef ASSERT 2337// verify the JavaThread has not yet been published in the Threads::list, and 2338// hence doesn't need protection from concurrent access at this stage 2339void JavaThread::verify_not_published() { 2340 if (!Threads_lock->owned_by_self()) { 2341 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2342 assert( !Threads::includes(this), 2343 "java thread shouldn't have been published yet!"); 2344 } 2345 else { 2346 assert( !Threads::includes(this), 2347 "java thread shouldn't have been published yet!"); 2348 } 2349} 2350#endif 2351 2352// Slow path when the native==>VM/Java barriers detect a safepoint is in 2353// progress or when _suspend_flags is non-zero. 2354// Current thread needs to self-suspend if there is a suspend request and/or 2355// block if a safepoint is in progress. 2356// Async exception ISN'T checked. 2357// Note only the ThreadInVMfromNative transition can call this function 2358// directly and when thread state is _thread_in_native_trans 2359void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2360 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2361 2362 JavaThread *curJT = JavaThread::current(); 2363 bool do_self_suspend = thread->is_external_suspend(); 2364 2365 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2366 2367 // If JNIEnv proxies are allowed, don't self-suspend if the target 2368 // thread is not the current thread. In older versions of jdbx, jdbx 2369 // threads could call into the VM with another thread's JNIEnv so we 2370 // can be here operating on behalf of a suspended thread (4432884). 2371 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2372 JavaThreadState state = thread->thread_state(); 2373 2374 // We mark this thread_blocked state as a suspend-equivalent so 2375 // that a caller to is_ext_suspend_completed() won't be confused. 2376 // The suspend-equivalent state is cleared by java_suspend_self(). 2377 thread->set_suspend_equivalent(); 2378 2379 // If the safepoint code sees the _thread_in_native_trans state, it will 2380 // wait until the thread changes to other thread state. There is no 2381 // guarantee on how soon we can obtain the SR_lock and complete the 2382 // self-suspend request. It would be a bad idea to let safepoint wait for 2383 // too long. Temporarily change the state to _thread_blocked to 2384 // let the VM thread know that this thread is ready for GC. The problem 2385 // of changing thread state is that safepoint could happen just after 2386 // java_suspend_self() returns after being resumed, and VM thread will 2387 // see the _thread_blocked state. We must check for safepoint 2388 // after restoring the state and make sure we won't leave while a safepoint 2389 // is in progress. 2390 thread->set_thread_state(_thread_blocked); 2391 thread->java_suspend_self(); 2392 thread->set_thread_state(state); 2393 // Make sure new state is seen by VM thread 2394 if (os::is_MP()) { 2395 if (UseMembar) { 2396 // Force a fence between the write above and read below 2397 OrderAccess::fence(); 2398 } else { 2399 // Must use this rather than serialization page in particular on Windows 2400 InterfaceSupport::serialize_memory(thread); 2401 } 2402 } 2403 } 2404 2405 if (SafepointSynchronize::do_call_back()) { 2406 // If we are safepointing, then block the caller which may not be 2407 // the same as the target thread (see above). 2408 SafepointSynchronize::block(curJT); 2409 } 2410 2411 if (thread->is_deopt_suspend()) { 2412 thread->clear_deopt_suspend(); 2413 RegisterMap map(thread, false); 2414 frame f = thread->last_frame(); 2415 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2416 f = f.sender(&map); 2417 } 2418 if (f.id() == thread->must_deopt_id()) { 2419 thread->clear_must_deopt_id(); 2420 f.deoptimize(thread); 2421 } else { 2422 fatal("missed deoptimization!"); 2423 } 2424 } 2425} 2426 2427// Slow path when the native==>VM/Java barriers detect a safepoint is in 2428// progress or when _suspend_flags is non-zero. 2429// Current thread needs to self-suspend if there is a suspend request and/or 2430// block if a safepoint is in progress. 2431// Also check for pending async exception (not including unsafe access error). 2432// Note only the native==>VM/Java barriers can call this function and when 2433// thread state is _thread_in_native_trans. 2434void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2435 check_safepoint_and_suspend_for_native_trans(thread); 2436 2437 if (thread->has_async_exception()) { 2438 // We are in _thread_in_native_trans state, don't handle unsafe 2439 // access error since that may block. 2440 thread->check_and_handle_async_exceptions(false); 2441 } 2442} 2443 2444// This is a variant of the normal 2445// check_special_condition_for_native_trans with slightly different 2446// semantics for use by critical native wrappers. It does all the 2447// normal checks but also performs the transition back into 2448// thread_in_Java state. This is required so that critical natives 2449// can potentially block and perform a GC if they are the last thread 2450// exiting the GC_locker. 2451void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2452 check_special_condition_for_native_trans(thread); 2453 2454 // Finish the transition 2455 thread->set_thread_state(_thread_in_Java); 2456 2457 if (thread->do_critical_native_unlock()) { 2458 ThreadInVMfromJavaNoAsyncException tiv(thread); 2459 GC_locker::unlock_critical(thread); 2460 thread->clear_critical_native_unlock(); 2461 } 2462} 2463 2464// We need to guarantee the Threads_lock here, since resumes are not 2465// allowed during safepoint synchronization 2466// Can only resume from an external suspension 2467void JavaThread::java_resume() { 2468 assert_locked_or_safepoint(Threads_lock); 2469 2470 // Sanity check: thread is gone, has started exiting or the thread 2471 // was not externally suspended. 2472 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2473 return; 2474 } 2475 2476 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2477 2478 clear_external_suspend(); 2479 2480 if (is_ext_suspended()) { 2481 clear_ext_suspended(); 2482 SR_lock()->notify_all(); 2483 } 2484} 2485 2486void JavaThread::create_stack_guard_pages() { 2487 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2488 address low_addr = stack_base() - stack_size(); 2489 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2490 2491 int allocate = os::allocate_stack_guard_pages(); 2492 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2493 2494 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2495 warning("Attempt to allocate stack guard pages failed."); 2496 return; 2497 } 2498 2499 if (os::guard_memory((char *) low_addr, len)) { 2500 _stack_guard_state = stack_guard_enabled; 2501 } else { 2502 warning("Attempt to protect stack guard pages failed."); 2503 if (os::uncommit_memory((char *) low_addr, len)) { 2504 warning("Attempt to deallocate stack guard pages failed."); 2505 } 2506 } 2507} 2508 2509void JavaThread::remove_stack_guard_pages() { 2510 assert(Thread::current() == this, "from different thread"); 2511 if (_stack_guard_state == stack_guard_unused) return; 2512 address low_addr = stack_base() - stack_size(); 2513 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2514 2515 if (os::allocate_stack_guard_pages()) { 2516 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2517 _stack_guard_state = stack_guard_unused; 2518 } else { 2519 warning("Attempt to deallocate stack guard pages failed."); 2520 } 2521 } else { 2522 if (_stack_guard_state == stack_guard_unused) return; 2523 if (os::unguard_memory((char *) low_addr, len)) { 2524 _stack_guard_state = stack_guard_unused; 2525 } else { 2526 warning("Attempt to unprotect stack guard pages failed."); 2527 } 2528 } 2529} 2530 2531void JavaThread::enable_stack_yellow_zone() { 2532 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2533 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2534 2535 // The base notation is from the stacks point of view, growing downward. 2536 // We need to adjust it to work correctly with guard_memory() 2537 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2538 2539 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2540 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2541 2542 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2543 _stack_guard_state = stack_guard_enabled; 2544 } else { 2545 warning("Attempt to guard stack yellow zone failed."); 2546 } 2547 enable_register_stack_guard(); 2548} 2549 2550void JavaThread::disable_stack_yellow_zone() { 2551 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2552 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2553 2554 // Simply return if called for a thread that does not use guard pages. 2555 if (_stack_guard_state == stack_guard_unused) return; 2556 2557 // The base notation is from the stacks point of view, growing downward. 2558 // We need to adjust it to work correctly with guard_memory() 2559 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2560 2561 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2562 _stack_guard_state = stack_guard_yellow_disabled; 2563 } else { 2564 warning("Attempt to unguard stack yellow zone failed."); 2565 } 2566 disable_register_stack_guard(); 2567} 2568 2569void JavaThread::enable_stack_red_zone() { 2570 // The base notation is from the stacks point of view, growing downward. 2571 // We need to adjust it to work correctly with guard_memory() 2572 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2573 address base = stack_red_zone_base() - stack_red_zone_size(); 2574 2575 guarantee(base < stack_base(),"Error calculating stack red zone"); 2576 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2577 2578 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2579 warning("Attempt to guard stack red zone failed."); 2580 } 2581} 2582 2583void JavaThread::disable_stack_red_zone() { 2584 // The base notation is from the stacks point of view, growing downward. 2585 // We need to adjust it to work correctly with guard_memory() 2586 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2587 address base = stack_red_zone_base() - stack_red_zone_size(); 2588 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2589 warning("Attempt to unguard stack red zone failed."); 2590 } 2591} 2592 2593void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2594 // ignore is there is no stack 2595 if (!has_last_Java_frame()) return; 2596 // traverse the stack frames. Starts from top frame. 2597 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2598 frame* fr = fst.current(); 2599 f(fr, fst.register_map()); 2600 } 2601} 2602 2603 2604#ifndef PRODUCT 2605// Deoptimization 2606// Function for testing deoptimization 2607void JavaThread::deoptimize() { 2608 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2609 StackFrameStream fst(this, UseBiasedLocking); 2610 bool deopt = false; // Dump stack only if a deopt actually happens. 2611 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2612 // Iterate over all frames in the thread and deoptimize 2613 for(; !fst.is_done(); fst.next()) { 2614 if(fst.current()->can_be_deoptimized()) { 2615 2616 if (only_at) { 2617 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2618 // consists of comma or carriage return separated numbers so 2619 // search for the current bci in that string. 2620 address pc = fst.current()->pc(); 2621 nmethod* nm = (nmethod*) fst.current()->cb(); 2622 ScopeDesc* sd = nm->scope_desc_at( pc); 2623 char buffer[8]; 2624 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2625 size_t len = strlen(buffer); 2626 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2627 while (found != NULL) { 2628 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2629 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2630 // Check that the bci found is bracketed by terminators. 2631 break; 2632 } 2633 found = strstr(found + 1, buffer); 2634 } 2635 if (!found) { 2636 continue; 2637 } 2638 } 2639 2640 if (DebugDeoptimization && !deopt) { 2641 deopt = true; // One-time only print before deopt 2642 tty->print_cr("[BEFORE Deoptimization]"); 2643 trace_frames(); 2644 trace_stack(); 2645 } 2646 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2647 } 2648 } 2649 2650 if (DebugDeoptimization && deopt) { 2651 tty->print_cr("[AFTER Deoptimization]"); 2652 trace_frames(); 2653 } 2654} 2655 2656 2657// Make zombies 2658void JavaThread::make_zombies() { 2659 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2660 if (fst.current()->can_be_deoptimized()) { 2661 // it is a Java nmethod 2662 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2663 nm->make_not_entrant(); 2664 } 2665 } 2666} 2667#endif // PRODUCT 2668 2669 2670void JavaThread::deoptimized_wrt_marked_nmethods() { 2671 if (!has_last_Java_frame()) return; 2672 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2673 StackFrameStream fst(this, UseBiasedLocking); 2674 for(; !fst.is_done(); fst.next()) { 2675 if (fst.current()->should_be_deoptimized()) { 2676 if (LogCompilation && xtty != NULL) { 2677 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2678 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2679 this->name(), nm != NULL ? nm->compile_id() : -1); 2680 } 2681 2682 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2683 } 2684 } 2685} 2686 2687 2688// GC support 2689static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2690 2691void JavaThread::gc_epilogue() { 2692 frames_do(frame_gc_epilogue); 2693} 2694 2695 2696static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2697 2698void JavaThread::gc_prologue() { 2699 frames_do(frame_gc_prologue); 2700} 2701 2702// If the caller is a NamedThread, then remember, in the current scope, 2703// the given JavaThread in its _processed_thread field. 2704class RememberProcessedThread: public StackObj { 2705 NamedThread* _cur_thr; 2706public: 2707 RememberProcessedThread(JavaThread* jthr) { 2708 Thread* thread = Thread::current(); 2709 if (thread->is_Named_thread()) { 2710 _cur_thr = (NamedThread *)thread; 2711 _cur_thr->set_processed_thread(jthr); 2712 } else { 2713 _cur_thr = NULL; 2714 } 2715 } 2716 2717 ~RememberProcessedThread() { 2718 if (_cur_thr) { 2719 _cur_thr->set_processed_thread(NULL); 2720 } 2721 } 2722}; 2723 2724void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 2725 // Verify that the deferred card marks have been flushed. 2726 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2727 2728 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2729 // since there may be more than one thread using each ThreadProfiler. 2730 2731 // Traverse the GCHandles 2732 Thread::oops_do(f, cld_f, cf); 2733 2734 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2735 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2736 2737 if (has_last_Java_frame()) { 2738 // Record JavaThread to GC thread 2739 RememberProcessedThread rpt(this); 2740 2741 // Traverse the privileged stack 2742 if (_privileged_stack_top != NULL) { 2743 _privileged_stack_top->oops_do(f); 2744 } 2745 2746 // traverse the registered growable array 2747 if (_array_for_gc != NULL) { 2748 for (int index = 0; index < _array_for_gc->length(); index++) { 2749 f->do_oop(_array_for_gc->adr_at(index)); 2750 } 2751 } 2752 2753 // Traverse the monitor chunks 2754 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2755 chunk->oops_do(f); 2756 } 2757 2758 // Traverse the execution stack 2759 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2760 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2761 } 2762 } 2763 2764 // callee_target is never live across a gc point so NULL it here should 2765 // it still contain a methdOop. 2766 2767 set_callee_target(NULL); 2768 2769 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2770 // If we have deferred set_locals there might be oops waiting to be 2771 // written 2772 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2773 if (list != NULL) { 2774 for (int i = 0; i < list->length(); i++) { 2775 list->at(i)->oops_do(f); 2776 } 2777 } 2778 2779 // Traverse instance variables at the end since the GC may be moving things 2780 // around using this function 2781 f->do_oop((oop*) &_threadObj); 2782 f->do_oop((oop*) &_vm_result); 2783 f->do_oop((oop*) &_exception_oop); 2784 f->do_oop((oop*) &_pending_async_exception); 2785 2786 if (jvmti_thread_state() != NULL) { 2787 jvmti_thread_state()->oops_do(f); 2788 } 2789} 2790 2791void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2792 Thread::nmethods_do(cf); // (super method is a no-op) 2793 2794 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2795 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2796 2797 if (has_last_Java_frame()) { 2798 // Traverse the execution stack 2799 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2800 fst.current()->nmethods_do(cf); 2801 } 2802 } 2803} 2804 2805void JavaThread::metadata_do(void f(Metadata*)) { 2806 Thread::metadata_do(f); 2807 if (has_last_Java_frame()) { 2808 // Traverse the execution stack to call f() on the methods in the stack 2809 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2810 fst.current()->metadata_do(f); 2811 } 2812 } else if (is_Compiler_thread()) { 2813 // need to walk ciMetadata in current compile tasks to keep alive. 2814 CompilerThread* ct = (CompilerThread*)this; 2815 if (ct->env() != NULL) { 2816 ct->env()->metadata_do(f); 2817 } 2818 } 2819} 2820 2821// Printing 2822const char* _get_thread_state_name(JavaThreadState _thread_state) { 2823 switch (_thread_state) { 2824 case _thread_uninitialized: return "_thread_uninitialized"; 2825 case _thread_new: return "_thread_new"; 2826 case _thread_new_trans: return "_thread_new_trans"; 2827 case _thread_in_native: return "_thread_in_native"; 2828 case _thread_in_native_trans: return "_thread_in_native_trans"; 2829 case _thread_in_vm: return "_thread_in_vm"; 2830 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2831 case _thread_in_Java: return "_thread_in_Java"; 2832 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2833 case _thread_blocked: return "_thread_blocked"; 2834 case _thread_blocked_trans: return "_thread_blocked_trans"; 2835 default: return "unknown thread state"; 2836 } 2837} 2838 2839#ifndef PRODUCT 2840void JavaThread::print_thread_state_on(outputStream *st) const { 2841 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2842}; 2843void JavaThread::print_thread_state() const { 2844 print_thread_state_on(tty); 2845}; 2846#endif // PRODUCT 2847 2848// Called by Threads::print() for VM_PrintThreads operation 2849void JavaThread::print_on(outputStream *st) const { 2850 st->print("\"%s\" ", get_thread_name()); 2851 oop thread_oop = threadObj(); 2852 if (thread_oop != NULL) { 2853 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2854 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2855 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2856 } 2857 Thread::print_on(st); 2858 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2859 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2860 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2861 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2862 } 2863#ifndef PRODUCT 2864 print_thread_state_on(st); 2865 _safepoint_state->print_on(st); 2866#endif // PRODUCT 2867} 2868 2869// Called by fatal error handler. The difference between this and 2870// JavaThread::print() is that we can't grab lock or allocate memory. 2871void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2872 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2873 oop thread_obj = threadObj(); 2874 if (thread_obj != NULL) { 2875 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2876 } 2877 st->print(" ["); 2878 st->print("%s", _get_thread_state_name(_thread_state)); 2879 if (osthread()) { 2880 st->print(", id=%d", osthread()->thread_id()); 2881 } 2882 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2883 _stack_base - _stack_size, _stack_base); 2884 st->print("]"); 2885 return; 2886} 2887 2888// Verification 2889 2890static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2891 2892void JavaThread::verify() { 2893 // Verify oops in the thread. 2894 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2895 2896 // Verify the stack frames. 2897 frames_do(frame_verify); 2898} 2899 2900// CR 6300358 (sub-CR 2137150) 2901// Most callers of this method assume that it can't return NULL but a 2902// thread may not have a name whilst it is in the process of attaching to 2903// the VM - see CR 6412693, and there are places where a JavaThread can be 2904// seen prior to having it's threadObj set (eg JNI attaching threads and 2905// if vm exit occurs during initialization). These cases can all be accounted 2906// for such that this method never returns NULL. 2907const char* JavaThread::get_thread_name() const { 2908#ifdef ASSERT 2909 // early safepoints can hit while current thread does not yet have TLS 2910 if (!SafepointSynchronize::is_at_safepoint()) { 2911 Thread *cur = Thread::current(); 2912 if (!(cur->is_Java_thread() && cur == this)) { 2913 // Current JavaThreads are allowed to get their own name without 2914 // the Threads_lock. 2915 assert_locked_or_safepoint(Threads_lock); 2916 } 2917 } 2918#endif // ASSERT 2919 return get_thread_name_string(); 2920} 2921 2922// Returns a non-NULL representation of this thread's name, or a suitable 2923// descriptive string if there is no set name 2924const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2925 const char* name_str; 2926 oop thread_obj = threadObj(); 2927 if (thread_obj != NULL) { 2928 typeArrayOop name = java_lang_Thread::name(thread_obj); 2929 if (name != NULL) { 2930 if (buf == NULL) { 2931 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2932 } 2933 else { 2934 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2935 } 2936 } 2937 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2938 name_str = "<no-name - thread is attaching>"; 2939 } 2940 else { 2941 name_str = Thread::name(); 2942 } 2943 } 2944 else { 2945 name_str = Thread::name(); 2946 } 2947 assert(name_str != NULL, "unexpected NULL thread name"); 2948 return name_str; 2949} 2950 2951 2952const char* JavaThread::get_threadgroup_name() const { 2953 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2954 oop thread_obj = threadObj(); 2955 if (thread_obj != NULL) { 2956 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2957 if (thread_group != NULL) { 2958 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2959 // ThreadGroup.name can be null 2960 if (name != NULL) { 2961 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2962 return str; 2963 } 2964 } 2965 } 2966 return NULL; 2967} 2968 2969const char* JavaThread::get_parent_name() const { 2970 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2971 oop thread_obj = threadObj(); 2972 if (thread_obj != NULL) { 2973 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2974 if (thread_group != NULL) { 2975 oop parent = java_lang_ThreadGroup::parent(thread_group); 2976 if (parent != NULL) { 2977 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2978 // ThreadGroup.name can be null 2979 if (name != NULL) { 2980 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2981 return str; 2982 } 2983 } 2984 } 2985 } 2986 return NULL; 2987} 2988 2989ThreadPriority JavaThread::java_priority() const { 2990 oop thr_oop = threadObj(); 2991 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2992 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2993 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2994 return priority; 2995} 2996 2997void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2998 2999 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3000 // Link Java Thread object <-> C++ Thread 3001 3002 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3003 // and put it into a new Handle. The Handle "thread_oop" can then 3004 // be used to pass the C++ thread object to other methods. 3005 3006 // Set the Java level thread object (jthread) field of the 3007 // new thread (a JavaThread *) to C++ thread object using the 3008 // "thread_oop" handle. 3009 3010 // Set the thread field (a JavaThread *) of the 3011 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3012 3013 Handle thread_oop(Thread::current(), 3014 JNIHandles::resolve_non_null(jni_thread)); 3015 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3016 "must be initialized"); 3017 set_threadObj(thread_oop()); 3018 java_lang_Thread::set_thread(thread_oop(), this); 3019 3020 if (prio == NoPriority) { 3021 prio = java_lang_Thread::priority(thread_oop()); 3022 assert(prio != NoPriority, "A valid priority should be present"); 3023 } 3024 3025 // Push the Java priority down to the native thread; needs Threads_lock 3026 Thread::set_priority(this, prio); 3027 3028 // Add the new thread to the Threads list and set it in motion. 3029 // We must have threads lock in order to call Threads::add. 3030 // It is crucial that we do not block before the thread is 3031 // added to the Threads list for if a GC happens, then the java_thread oop 3032 // will not be visited by GC. 3033 Threads::add(this); 3034} 3035 3036oop JavaThread::current_park_blocker() { 3037 // Support for JSR-166 locks 3038 oop thread_oop = threadObj(); 3039 if (thread_oop != NULL && 3040 JDK_Version::current().supports_thread_park_blocker()) { 3041 return java_lang_Thread::park_blocker(thread_oop); 3042 } 3043 return NULL; 3044} 3045 3046 3047void JavaThread::print_stack_on(outputStream* st) { 3048 if (!has_last_Java_frame()) return; 3049 ResourceMark rm; 3050 HandleMark hm; 3051 3052 RegisterMap reg_map(this); 3053 vframe* start_vf = last_java_vframe(®_map); 3054 int count = 0; 3055 for (vframe* f = start_vf; f; f = f->sender() ) { 3056 if (f->is_java_frame()) { 3057 javaVFrame* jvf = javaVFrame::cast(f); 3058 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3059 3060 // Print out lock information 3061 if (JavaMonitorsInStackTrace) { 3062 jvf->print_lock_info_on(st, count); 3063 } 3064 } else { 3065 // Ignore non-Java frames 3066 } 3067 3068 // Bail-out case for too deep stacks 3069 count++; 3070 if (MaxJavaStackTraceDepth == count) return; 3071 } 3072} 3073 3074 3075// JVMTI PopFrame support 3076void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3077 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3078 if (in_bytes(size_in_bytes) != 0) { 3079 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3080 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3081 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3082 } 3083} 3084 3085void* JavaThread::popframe_preserved_args() { 3086 return _popframe_preserved_args; 3087} 3088 3089ByteSize JavaThread::popframe_preserved_args_size() { 3090 return in_ByteSize(_popframe_preserved_args_size); 3091} 3092 3093WordSize JavaThread::popframe_preserved_args_size_in_words() { 3094 int sz = in_bytes(popframe_preserved_args_size()); 3095 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3096 return in_WordSize(sz / wordSize); 3097} 3098 3099void JavaThread::popframe_free_preserved_args() { 3100 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3101 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3102 _popframe_preserved_args = NULL; 3103 _popframe_preserved_args_size = 0; 3104} 3105 3106#ifndef PRODUCT 3107 3108void JavaThread::trace_frames() { 3109 tty->print_cr("[Describe stack]"); 3110 int frame_no = 1; 3111 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3112 tty->print(" %d. ", frame_no++); 3113 fst.current()->print_value_on(tty,this); 3114 tty->cr(); 3115 } 3116} 3117 3118class PrintAndVerifyOopClosure: public OopClosure { 3119 protected: 3120 template <class T> inline void do_oop_work(T* p) { 3121 oop obj = oopDesc::load_decode_heap_oop(p); 3122 if (obj == NULL) return; 3123 tty->print(INTPTR_FORMAT ": ", p); 3124 if (obj->is_oop_or_null()) { 3125 if (obj->is_objArray()) { 3126 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3127 } else { 3128 obj->print(); 3129 } 3130 } else { 3131 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3132 } 3133 tty->cr(); 3134 } 3135 public: 3136 virtual void do_oop(oop* p) { do_oop_work(p); } 3137 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3138}; 3139 3140 3141static void oops_print(frame* f, const RegisterMap *map) { 3142 PrintAndVerifyOopClosure print; 3143 f->print_value(); 3144 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3145} 3146 3147// Print our all the locations that contain oops and whether they are 3148// valid or not. This useful when trying to find the oldest frame 3149// where an oop has gone bad since the frame walk is from youngest to 3150// oldest. 3151void JavaThread::trace_oops() { 3152 tty->print_cr("[Trace oops]"); 3153 frames_do(oops_print); 3154} 3155 3156 3157#ifdef ASSERT 3158// Print or validate the layout of stack frames 3159void JavaThread::print_frame_layout(int depth, bool validate_only) { 3160 ResourceMark rm; 3161 PRESERVE_EXCEPTION_MARK; 3162 FrameValues values; 3163 int frame_no = 0; 3164 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3165 fst.current()->describe(values, ++frame_no); 3166 if (depth == frame_no) break; 3167 } 3168 if (validate_only) { 3169 values.validate(); 3170 } else { 3171 tty->print_cr("[Describe stack layout]"); 3172 values.print(this); 3173 } 3174} 3175#endif 3176 3177void JavaThread::trace_stack_from(vframe* start_vf) { 3178 ResourceMark rm; 3179 int vframe_no = 1; 3180 for (vframe* f = start_vf; f; f = f->sender() ) { 3181 if (f->is_java_frame()) { 3182 javaVFrame::cast(f)->print_activation(vframe_no++); 3183 } else { 3184 f->print(); 3185 } 3186 if (vframe_no > StackPrintLimit) { 3187 tty->print_cr("...<more frames>..."); 3188 return; 3189 } 3190 } 3191} 3192 3193 3194void JavaThread::trace_stack() { 3195 if (!has_last_Java_frame()) return; 3196 ResourceMark rm; 3197 HandleMark hm; 3198 RegisterMap reg_map(this); 3199 trace_stack_from(last_java_vframe(®_map)); 3200} 3201 3202 3203#endif // PRODUCT 3204 3205 3206javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3207 assert(reg_map != NULL, "a map must be given"); 3208 frame f = last_frame(); 3209 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3210 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3211 } 3212 return NULL; 3213} 3214 3215 3216Klass* JavaThread::security_get_caller_class(int depth) { 3217 vframeStream vfst(this); 3218 vfst.security_get_caller_frame(depth); 3219 if (!vfst.at_end()) { 3220 return vfst.method()->method_holder(); 3221 } 3222 return NULL; 3223} 3224 3225static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3226 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3227 CompileBroker::compiler_thread_loop(); 3228} 3229 3230// Create a CompilerThread 3231CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3232: JavaThread(&compiler_thread_entry) { 3233 _env = NULL; 3234 _log = NULL; 3235 _task = NULL; 3236 _queue = queue; 3237 _counters = counters; 3238 _buffer_blob = NULL; 3239 _scanned_nmethod = NULL; 3240 3241#ifndef PRODUCT 3242 _ideal_graph_printer = NULL; 3243#endif 3244} 3245 3246void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 3247 JavaThread::oops_do(f, cld_f, cf); 3248 if (_scanned_nmethod != NULL && cf != NULL) { 3249 // Safepoints can occur when the sweeper is scanning an nmethod so 3250 // process it here to make sure it isn't unloaded in the middle of 3251 // a scan. 3252 cf->do_code_blob(_scanned_nmethod); 3253 } 3254} 3255 3256// ======= Threads ======== 3257 3258// The Threads class links together all active threads, and provides 3259// operations over all threads. It is protected by its own Mutex 3260// lock, which is also used in other contexts to protect thread 3261// operations from having the thread being operated on from exiting 3262// and going away unexpectedly (e.g., safepoint synchronization) 3263 3264JavaThread* Threads::_thread_list = NULL; 3265int Threads::_number_of_threads = 0; 3266int Threads::_number_of_non_daemon_threads = 0; 3267int Threads::_return_code = 0; 3268size_t JavaThread::_stack_size_at_create = 0; 3269#ifdef ASSERT 3270bool Threads::_vm_complete = false; 3271#endif 3272 3273// All JavaThreads 3274#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3275 3276void os_stream(); 3277 3278// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3279void Threads::threads_do(ThreadClosure* tc) { 3280 assert_locked_or_safepoint(Threads_lock); 3281 // ALL_JAVA_THREADS iterates through all JavaThreads 3282 ALL_JAVA_THREADS(p) { 3283 tc->do_thread(p); 3284 } 3285 // Someday we could have a table or list of all non-JavaThreads. 3286 // For now, just manually iterate through them. 3287 tc->do_thread(VMThread::vm_thread()); 3288 Universe::heap()->gc_threads_do(tc); 3289 WatcherThread *wt = WatcherThread::watcher_thread(); 3290 // Strictly speaking, the following NULL check isn't sufficient to make sure 3291 // the data for WatcherThread is still valid upon being examined. However, 3292 // considering that WatchThread terminates when the VM is on the way to 3293 // exit at safepoint, the chance of the above is extremely small. The right 3294 // way to prevent termination of WatcherThread would be to acquire 3295 // Terminator_lock, but we can't do that without violating the lock rank 3296 // checking in some cases. 3297 if (wt != NULL) 3298 tc->do_thread(wt); 3299 3300 // If CompilerThreads ever become non-JavaThreads, add them here 3301} 3302 3303jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3304 3305 extern void JDK_Version_init(); 3306 3307 // Check version 3308 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3309 3310 // Initialize the output stream module 3311 ostream_init(); 3312 3313 // Process java launcher properties. 3314 Arguments::process_sun_java_launcher_properties(args); 3315 3316 // Initialize the os module before using TLS 3317 os::init(); 3318 3319 // Initialize system properties. 3320 Arguments::init_system_properties(); 3321 3322 // So that JDK version can be used as a discrimintor when parsing arguments 3323 JDK_Version_init(); 3324 3325 // Update/Initialize System properties after JDK version number is known 3326 Arguments::init_version_specific_system_properties(); 3327 3328 // Parse arguments 3329 jint parse_result = Arguments::parse(args); 3330 if (parse_result != JNI_OK) return parse_result; 3331 3332 if (PauseAtStartup) { 3333 os::pause(); 3334 } 3335 3336#ifndef USDT2 3337 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3338#else /* USDT2 */ 3339 HOTSPOT_VM_INIT_BEGIN(); 3340#endif /* USDT2 */ 3341 3342 // Record VM creation timing statistics 3343 TraceVmCreationTime create_vm_timer; 3344 create_vm_timer.start(); 3345 3346 // Timing (must come after argument parsing) 3347 TraceTime timer("Create VM", TraceStartupTime); 3348 3349 // Initialize the os module after parsing the args 3350 jint os_init_2_result = os::init_2(); 3351 if (os_init_2_result != JNI_OK) return os_init_2_result; 3352 3353 jint adjust_after_os_result = Arguments::adjust_after_os(); 3354 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3355 3356 // intialize TLS 3357 ThreadLocalStorage::init(); 3358 3359 // Bootstrap native memory tracking, so it can start recording memory 3360 // activities before worker thread is started. This is the first phase 3361 // of bootstrapping, VM is currently running in single-thread mode. 3362 MemTracker::bootstrap_single_thread(); 3363 3364 // Initialize output stream logging 3365 ostream_init_log(); 3366 3367 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3368 // Must be before create_vm_init_agents() 3369 if (Arguments::init_libraries_at_startup()) { 3370 convert_vm_init_libraries_to_agents(); 3371 } 3372 3373 // Launch -agentlib/-agentpath and converted -Xrun agents 3374 if (Arguments::init_agents_at_startup()) { 3375 create_vm_init_agents(); 3376 } 3377 3378 // Initialize Threads state 3379 _thread_list = NULL; 3380 _number_of_threads = 0; 3381 _number_of_non_daemon_threads = 0; 3382 3383 // Initialize global data structures and create system classes in heap 3384 vm_init_globals(); 3385 3386 // Attach the main thread to this os thread 3387 JavaThread* main_thread = new JavaThread(); 3388 main_thread->set_thread_state(_thread_in_vm); 3389 // must do this before set_active_handles and initialize_thread_local_storage 3390 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3391 // change the stack size recorded here to one based on the java thread 3392 // stacksize. This adjusted size is what is used to figure the placement 3393 // of the guard pages. 3394 main_thread->record_stack_base_and_size(); 3395 main_thread->initialize_thread_local_storage(); 3396 3397 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3398 3399 if (!main_thread->set_as_starting_thread()) { 3400 vm_shutdown_during_initialization( 3401 "Failed necessary internal allocation. Out of swap space"); 3402 delete main_thread; 3403 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3404 return JNI_ENOMEM; 3405 } 3406 3407 // Enable guard page *after* os::create_main_thread(), otherwise it would 3408 // crash Linux VM, see notes in os_linux.cpp. 3409 main_thread->create_stack_guard_pages(); 3410 3411 // Initialize Java-Level synchronization subsystem 3412 ObjectMonitor::Initialize() ; 3413 3414 // Second phase of bootstrapping, VM is about entering multi-thread mode 3415 MemTracker::bootstrap_multi_thread(); 3416 3417 // Initialize global modules 3418 jint status = init_globals(); 3419 if (status != JNI_OK) { 3420 delete main_thread; 3421 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3422 return status; 3423 } 3424 3425 // Should be done after the heap is fully created 3426 main_thread->cache_global_variables(); 3427 3428 HandleMark hm; 3429 3430 { MutexLocker mu(Threads_lock); 3431 Threads::add(main_thread); 3432 } 3433 3434 // Any JVMTI raw monitors entered in onload will transition into 3435 // real raw monitor. VM is setup enough here for raw monitor enter. 3436 JvmtiExport::transition_pending_onload_raw_monitors(); 3437 3438 // Fully start NMT 3439 MemTracker::start(); 3440 3441 // Create the VMThread 3442 { TraceTime timer("Start VMThread", TraceStartupTime); 3443 VMThread::create(); 3444 Thread* vmthread = VMThread::vm_thread(); 3445 3446 if (!os::create_thread(vmthread, os::vm_thread)) 3447 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3448 3449 // Wait for the VM thread to become ready, and VMThread::run to initialize 3450 // Monitors can have spurious returns, must always check another state flag 3451 { 3452 MutexLocker ml(Notify_lock); 3453 os::start_thread(vmthread); 3454 while (vmthread->active_handles() == NULL) { 3455 Notify_lock->wait(); 3456 } 3457 } 3458 } 3459 3460 assert (Universe::is_fully_initialized(), "not initialized"); 3461 if (VerifyDuringStartup) { 3462 // Make sure we're starting with a clean slate. 3463 VM_Verify verify_op; 3464 VMThread::execute(&verify_op); 3465 } 3466 3467 EXCEPTION_MARK; 3468 3469 // At this point, the Universe is initialized, but we have not executed 3470 // any byte code. Now is a good time (the only time) to dump out the 3471 // internal state of the JVM for sharing. 3472 if (DumpSharedSpaces) { 3473 MetaspaceShared::preload_and_dump(CHECK_0); 3474 ShouldNotReachHere(); 3475 } 3476 3477 // Always call even when there are not JVMTI environments yet, since environments 3478 // may be attached late and JVMTI must track phases of VM execution 3479 JvmtiExport::enter_start_phase(); 3480 3481 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3482 JvmtiExport::post_vm_start(); 3483 3484 { 3485 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3486 3487 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3488 create_vm_init_libraries(); 3489 } 3490 3491 initialize_class(vmSymbols::java_lang_String(), CHECK_0); 3492 3493 if (AggressiveOpts) { 3494 { 3495 // Forcibly initialize java/util/HashMap and mutate the private 3496 // static final "frontCacheEnabled" field before we start creating instances 3497#ifdef ASSERT 3498 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3499 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 3500#endif 3501 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3502 KlassHandle k = KlassHandle(THREAD, k_o); 3503 guarantee(k.not_null(), "Must find java/util/HashMap"); 3504 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3505 ik->initialize(CHECK_0); 3506 fieldDescriptor fd; 3507 // Possible we might not find this field; if so, don't break 3508 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3509 k()->java_mirror()->bool_field_put(fd.offset(), true); 3510 } 3511 } 3512 3513 if (UseStringCache) { 3514 // Forcibly initialize java/lang/StringValue and mutate the private 3515 // static final "stringCacheEnabled" field before we start creating instances 3516 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0); 3517 // Possible that StringValue isn't present: if so, silently don't break 3518 if (k_o != NULL) { 3519 KlassHandle k = KlassHandle(THREAD, k_o); 3520 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3521 ik->initialize(CHECK_0); 3522 fieldDescriptor fd; 3523 // Possible we might not find this field: if so, silently don't break 3524 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3525 k()->java_mirror()->bool_field_put(fd.offset(), true); 3526 } 3527 } 3528 } 3529 } 3530 3531 // Initialize java_lang.System (needed before creating the thread) 3532 initialize_class(vmSymbols::java_lang_System(), CHECK_0); 3533 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0); 3534 Handle thread_group = create_initial_thread_group(CHECK_0); 3535 Universe::set_main_thread_group(thread_group()); 3536 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0); 3537 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 3538 main_thread->set_threadObj(thread_object); 3539 // Set thread status to running since main thread has 3540 // been started and running. 3541 java_lang_Thread::set_thread_status(thread_object, 3542 java_lang_Thread::RUNNABLE); 3543 3544 // The VM creates & returns objects of this class. Make sure it's initialized. 3545 initialize_class(vmSymbols::java_lang_Class(), CHECK_0); 3546 3547 // The VM preresolves methods to these classes. Make sure that they get initialized 3548 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0); 3549 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0); 3550 call_initializeSystemClass(CHECK_0); 3551 3552 // get the Java runtime name after java.lang.System is initialized 3553 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3554 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3555 3556 // an instance of OutOfMemory exception has been allocated earlier 3557 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0); 3558 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0); 3559 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0); 3560 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0); 3561 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0); 3562 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0); 3563 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0); 3564 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0); 3565 } 3566 3567 // See : bugid 4211085. 3568 // Background : the static initializer of java.lang.Compiler tries to read 3569 // property"java.compiler" and read & write property "java.vm.info". 3570 // When a security manager is installed through the command line 3571 // option "-Djava.security.manager", the above properties are not 3572 // readable and the static initializer for java.lang.Compiler fails 3573 // resulting in a NoClassDefFoundError. This can happen in any 3574 // user code which calls methods in java.lang.Compiler. 3575 // Hack : the hack is to pre-load and initialize this class, so that only 3576 // system domains are on the stack when the properties are read. 3577 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3578 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3579 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3580 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3581 // Once that is done, we should remove this hack. 3582 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0); 3583 3584 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3585 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3586 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3587 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3588 // This should also be taken out as soon as 4211383 gets fixed. 3589 reset_vm_info_property(CHECK_0); 3590 3591 quicken_jni_functions(); 3592 3593 // Must be run after init_ft which initializes ft_enabled 3594 if (TRACE_INITIALIZE() != JNI_OK) { 3595 vm_exit_during_initialization("Failed to initialize tracing backend"); 3596 } 3597 3598 // Set flag that basic initialization has completed. Used by exceptions and various 3599 // debug stuff, that does not work until all basic classes have been initialized. 3600 set_init_completed(); 3601 3602#ifndef USDT2 3603 HS_DTRACE_PROBE(hotspot, vm__init__end); 3604#else /* USDT2 */ 3605 HOTSPOT_VM_INIT_END(); 3606#endif /* USDT2 */ 3607 3608 // record VM initialization completion time 3609#if INCLUDE_MANAGEMENT 3610 Management::record_vm_init_completed(); 3611#endif // INCLUDE_MANAGEMENT 3612 3613 // Compute system loader. Note that this has to occur after set_init_completed, since 3614 // valid exceptions may be thrown in the process. 3615 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3616 // set_init_completed has just been called, causing exceptions not to be shortcut 3617 // anymore. We call vm_exit_during_initialization directly instead. 3618 SystemDictionary::compute_java_system_loader(THREAD); 3619 if (HAS_PENDING_EXCEPTION) { 3620 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3621 } 3622 3623#if INCLUDE_ALL_GCS 3624 // Support for ConcurrentMarkSweep. This should be cleaned up 3625 // and better encapsulated. The ugly nested if test would go away 3626 // once things are properly refactored. XXX YSR 3627 if (UseConcMarkSweepGC || UseG1GC) { 3628 if (UseConcMarkSweepGC) { 3629 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3630 } else { 3631 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3632 } 3633 if (HAS_PENDING_EXCEPTION) { 3634 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3635 } 3636 } 3637#endif // INCLUDE_ALL_GCS 3638 3639 // Always call even when there are not JVMTI environments yet, since environments 3640 // may be attached late and JVMTI must track phases of VM execution 3641 JvmtiExport::enter_live_phase(); 3642 3643 // Signal Dispatcher needs to be started before VMInit event is posted 3644 os::signal_init(); 3645 3646 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3647 if (!DisableAttachMechanism) { 3648 AttachListener::vm_start(); 3649 if (StartAttachListener || AttachListener::init_at_startup()) { 3650 AttachListener::init(); 3651 } 3652 } 3653 3654 // Launch -Xrun agents 3655 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3656 // back-end can launch with -Xdebug -Xrunjdwp. 3657 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3658 create_vm_init_libraries(); 3659 } 3660 3661 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3662 JvmtiExport::post_vm_initialized(); 3663 3664 if (TRACE_START() != JNI_OK) { 3665 vm_exit_during_initialization("Failed to start tracing backend."); 3666 } 3667 3668 if (CleanChunkPoolAsync) { 3669 Chunk::start_chunk_pool_cleaner_task(); 3670 } 3671 3672 // initialize compiler(s) 3673#if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3674 CompileBroker::compilation_init(); 3675#endif 3676 3677#if INCLUDE_MANAGEMENT 3678 Management::initialize(THREAD); 3679#endif // INCLUDE_MANAGEMENT 3680 3681 if (HAS_PENDING_EXCEPTION) { 3682 // management agent fails to start possibly due to 3683 // configuration problem and is responsible for printing 3684 // stack trace if appropriate. Simply exit VM. 3685 vm_exit(1); 3686 } 3687 3688 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3689 if (MemProfiling) MemProfiler::engage(); 3690 StatSampler::engage(); 3691 if (CheckJNICalls) JniPeriodicChecker::engage(); 3692 3693 BiasedLocking::init(); 3694 3695 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3696 call_postVMInitHook(THREAD); 3697 // The Java side of PostVMInitHook.run must deal with all 3698 // exceptions and provide means of diagnosis. 3699 if (HAS_PENDING_EXCEPTION) { 3700 CLEAR_PENDING_EXCEPTION; 3701 } 3702 } 3703 3704 { 3705 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3706 // Make sure the watcher thread can be started by WatcherThread::start() 3707 // or by dynamic enrollment. 3708 WatcherThread::make_startable(); 3709 // Start up the WatcherThread if there are any periodic tasks 3710 // NOTE: All PeriodicTasks should be registered by now. If they 3711 // aren't, late joiners might appear to start slowly (we might 3712 // take a while to process their first tick). 3713 if (PeriodicTask::num_tasks() > 0) { 3714 WatcherThread::start(); 3715 } 3716 } 3717 3718 // Give os specific code one last chance to start 3719 os::init_3(); 3720 3721 create_vm_timer.end(); 3722#ifdef ASSERT 3723 _vm_complete = true; 3724#endif 3725 return JNI_OK; 3726} 3727 3728// type for the Agent_OnLoad and JVM_OnLoad entry points 3729extern "C" { 3730 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3731} 3732// Find a command line agent library and return its entry point for 3733// -agentlib: -agentpath: -Xrun 3734// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3735static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3736 OnLoadEntry_t on_load_entry = NULL; 3737 void *library = agent->os_lib(); // check if we have looked it up before 3738 3739 if (library == NULL) { 3740 char buffer[JVM_MAXPATHLEN]; 3741 char ebuf[1024]; 3742 const char *name = agent->name(); 3743 const char *msg = "Could not find agent library "; 3744 3745 if (agent->is_absolute_path()) { 3746 library = os::dll_load(name, ebuf, sizeof ebuf); 3747 if (library == NULL) { 3748 const char *sub_msg = " in absolute path, with error: "; 3749 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3750 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3751 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3752 // If we can't find the agent, exit. 3753 vm_exit_during_initialization(buf, NULL); 3754 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3755 } 3756 } else { 3757 // Try to load the agent from the standard dll directory 3758 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3759 name)) { 3760 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3761 } 3762 if (library == NULL) { // Try the local directory 3763 char ns[1] = {0}; 3764 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3765 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3766 } 3767 if (library == NULL) { 3768 const char *sub_msg = " on the library path, with error: "; 3769 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3770 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3771 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3772 // If we can't find the agent, exit. 3773 vm_exit_during_initialization(buf, NULL); 3774 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3775 } 3776 } 3777 } 3778 agent->set_os_lib(library); 3779 } 3780 3781 // Find the OnLoad function. 3782 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3783 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index])); 3784 if (on_load_entry != NULL) break; 3785 } 3786 return on_load_entry; 3787} 3788 3789// Find the JVM_OnLoad entry point 3790static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3791 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3792 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3793} 3794 3795// Find the Agent_OnLoad entry point 3796static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3797 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3798 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3799} 3800 3801// For backwards compatibility with -Xrun 3802// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3803// treated like -agentpath: 3804// Must be called before agent libraries are created 3805void Threads::convert_vm_init_libraries_to_agents() { 3806 AgentLibrary* agent; 3807 AgentLibrary* next; 3808 3809 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3810 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3811 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3812 3813 // If there is an JVM_OnLoad function it will get called later, 3814 // otherwise see if there is an Agent_OnLoad 3815 if (on_load_entry == NULL) { 3816 on_load_entry = lookup_agent_on_load(agent); 3817 if (on_load_entry != NULL) { 3818 // switch it to the agent list -- so that Agent_OnLoad will be called, 3819 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3820 Arguments::convert_library_to_agent(agent); 3821 } else { 3822 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3823 } 3824 } 3825 } 3826} 3827 3828// Create agents for -agentlib: -agentpath: and converted -Xrun 3829// Invokes Agent_OnLoad 3830// Called very early -- before JavaThreads exist 3831void Threads::create_vm_init_agents() { 3832 extern struct JavaVM_ main_vm; 3833 AgentLibrary* agent; 3834 3835 JvmtiExport::enter_onload_phase(); 3836 3837 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3838 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3839 3840 if (on_load_entry != NULL) { 3841 // Invoke the Agent_OnLoad function 3842 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3843 if (err != JNI_OK) { 3844 vm_exit_during_initialization("agent library failed to init", agent->name()); 3845 } 3846 } else { 3847 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3848 } 3849 } 3850 JvmtiExport::enter_primordial_phase(); 3851} 3852 3853extern "C" { 3854 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3855} 3856 3857void Threads::shutdown_vm_agents() { 3858 // Send any Agent_OnUnload notifications 3859 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3860 extern struct JavaVM_ main_vm; 3861 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3862 3863 // Find the Agent_OnUnload function. 3864 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3865 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3866 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3867 3868 // Invoke the Agent_OnUnload function 3869 if (unload_entry != NULL) { 3870 JavaThread* thread = JavaThread::current(); 3871 ThreadToNativeFromVM ttn(thread); 3872 HandleMark hm(thread); 3873 (*unload_entry)(&main_vm); 3874 break; 3875 } 3876 } 3877 } 3878} 3879 3880// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3881// Invokes JVM_OnLoad 3882void Threads::create_vm_init_libraries() { 3883 extern struct JavaVM_ main_vm; 3884 AgentLibrary* agent; 3885 3886 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3887 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3888 3889 if (on_load_entry != NULL) { 3890 // Invoke the JVM_OnLoad function 3891 JavaThread* thread = JavaThread::current(); 3892 ThreadToNativeFromVM ttn(thread); 3893 HandleMark hm(thread); 3894 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3895 if (err != JNI_OK) { 3896 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3897 } 3898 } else { 3899 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3900 } 3901 } 3902} 3903 3904// Last thread running calls java.lang.Shutdown.shutdown() 3905void JavaThread::invoke_shutdown_hooks() { 3906 HandleMark hm(this); 3907 3908 // We could get here with a pending exception, if so clear it now. 3909 if (this->has_pending_exception()) { 3910 this->clear_pending_exception(); 3911 } 3912 3913 EXCEPTION_MARK; 3914 Klass* k = 3915 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3916 THREAD); 3917 if (k != NULL) { 3918 // SystemDictionary::resolve_or_null will return null if there was 3919 // an exception. If we cannot load the Shutdown class, just don't 3920 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3921 // and finalizers (if runFinalizersOnExit is set) won't be run. 3922 // Note that if a shutdown hook was registered or runFinalizersOnExit 3923 // was called, the Shutdown class would have already been loaded 3924 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3925 instanceKlassHandle shutdown_klass (THREAD, k); 3926 JavaValue result(T_VOID); 3927 JavaCalls::call_static(&result, 3928 shutdown_klass, 3929 vmSymbols::shutdown_method_name(), 3930 vmSymbols::void_method_signature(), 3931 THREAD); 3932 } 3933 CLEAR_PENDING_EXCEPTION; 3934} 3935 3936// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3937// the program falls off the end of main(). Another VM exit path is through 3938// vm_exit() when the program calls System.exit() to return a value or when 3939// there is a serious error in VM. The two shutdown paths are not exactly 3940// the same, but they share Shutdown.shutdown() at Java level and before_exit() 3941// and VM_Exit op at VM level. 3942// 3943// Shutdown sequence: 3944// + Shutdown native memory tracking if it is on 3945// + Wait until we are the last non-daemon thread to execute 3946// <-- every thing is still working at this moment --> 3947// + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3948// shutdown hooks, run finalizers if finalization-on-exit 3949// + Call before_exit(), prepare for VM exit 3950// > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3951// currently the only user of this mechanism is File.deleteOnExit()) 3952// > stop flat profiler, StatSampler, watcher thread, CMS threads, 3953// post thread end and vm death events to JVMTI, 3954// stop signal thread 3955// + Call JavaThread::exit(), it will: 3956// > release JNI handle blocks, remove stack guard pages 3957// > remove this thread from Threads list 3958// <-- no more Java code from this thread after this point --> 3959// + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3960// the compiler threads at safepoint 3961// <-- do not use anything that could get blocked by Safepoint --> 3962// + Disable tracing at JNI/JVM barriers 3963// + Set _vm_exited flag for threads that are still running native code 3964// + Delete this thread 3965// + Call exit_globals() 3966// > deletes tty 3967// > deletes PerfMemory resources 3968// + Return to caller 3969 3970bool Threads::destroy_vm() { 3971 JavaThread* thread = JavaThread::current(); 3972 3973#ifdef ASSERT 3974 _vm_complete = false; 3975#endif 3976 // Wait until we are the last non-daemon thread to execute 3977 { MutexLocker nu(Threads_lock); 3978 while (Threads::number_of_non_daemon_threads() > 1 ) 3979 // This wait should make safepoint checks, wait without a timeout, 3980 // and wait as a suspend-equivalent condition. 3981 // 3982 // Note: If the FlatProfiler is running and this thread is waiting 3983 // for another non-daemon thread to finish, then the FlatProfiler 3984 // is waiting for the external suspend request on this thread to 3985 // complete. wait_for_ext_suspend_completion() will eventually 3986 // timeout, but that takes time. Making this wait a suspend- 3987 // equivalent condition solves that timeout problem. 3988 // 3989 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3990 Mutex::_as_suspend_equivalent_flag); 3991 } 3992 3993 // Hang forever on exit if we are reporting an error. 3994 if (ShowMessageBoxOnError && is_error_reported()) { 3995 os::infinite_sleep(); 3996 } 3997 os::wait_for_keypress_at_exit(); 3998 3999 if (JDK_Version::is_jdk12x_version()) { 4000 // We are the last thread running, so check if finalizers should be run. 4001 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 4002 HandleMark rm(thread); 4003 Universe::run_finalizers_on_exit(); 4004 } else { 4005 // run Java level shutdown hooks 4006 thread->invoke_shutdown_hooks(); 4007 } 4008 4009 before_exit(thread); 4010 4011 thread->exit(true); 4012 4013 // Stop VM thread. 4014 { 4015 // 4945125 The vm thread comes to a safepoint during exit. 4016 // GC vm_operations can get caught at the safepoint, and the 4017 // heap is unparseable if they are caught. Grab the Heap_lock 4018 // to prevent this. The GC vm_operations will not be able to 4019 // queue until after the vm thread is dead. 4020 // After this point, we'll never emerge out of the safepoint before 4021 // the VM exits, so concurrent GC threads do not need to be explicitly 4022 // stopped; they remain inactive until the process exits. 4023 // Note: some concurrent G1 threads may be running during a safepoint, 4024 // but these will not be accessing the heap, just some G1-specific side 4025 // data structures that are not accessed by any other threads but them 4026 // after this point in a terminal safepoint. 4027 4028 MutexLocker ml(Heap_lock); 4029 4030 VMThread::wait_for_vm_thread_exit(); 4031 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4032 VMThread::destroy(); 4033 } 4034 4035 // clean up ideal graph printers 4036#if defined(COMPILER2) && !defined(PRODUCT) 4037 IdealGraphPrinter::clean_up(); 4038#endif 4039 4040 // Now, all Java threads are gone except daemon threads. Daemon threads 4041 // running Java code or in VM are stopped by the Safepoint. However, 4042 // daemon threads executing native code are still running. But they 4043 // will be stopped at native=>Java/VM barriers. Note that we can't 4044 // simply kill or suspend them, as it is inherently deadlock-prone. 4045 4046#ifndef PRODUCT 4047 // disable function tracing at JNI/JVM barriers 4048 TraceJNICalls = false; 4049 TraceJVMCalls = false; 4050 TraceRuntimeCalls = false; 4051#endif 4052 4053 VM_Exit::set_vm_exited(); 4054 4055 notify_vm_shutdown(); 4056 4057 delete thread; 4058 4059 // exit_globals() will delete tty 4060 exit_globals(); 4061 4062 return true; 4063} 4064 4065 4066jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4067 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4068 return is_supported_jni_version(version); 4069} 4070 4071 4072jboolean Threads::is_supported_jni_version(jint version) { 4073 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4074 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4075 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4076 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4077 return JNI_FALSE; 4078} 4079 4080 4081void Threads::add(JavaThread* p, bool force_daemon) { 4082 // The threads lock must be owned at this point 4083 assert_locked_or_safepoint(Threads_lock); 4084 4085 // See the comment for this method in thread.hpp for its purpose and 4086 // why it is called here. 4087 p->initialize_queues(); 4088 p->set_next(_thread_list); 4089 _thread_list = p; 4090 _number_of_threads++; 4091 oop threadObj = p->threadObj(); 4092 bool daemon = true; 4093 // Bootstrapping problem: threadObj can be null for initial 4094 // JavaThread (or for threads attached via JNI) 4095 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4096 _number_of_non_daemon_threads++; 4097 daemon = false; 4098 } 4099 4100 p->set_safepoint_visible(true); 4101 4102 ThreadService::add_thread(p, daemon); 4103 4104 // Possible GC point. 4105 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4106} 4107 4108void Threads::remove(JavaThread* p) { 4109 // Extra scope needed for Thread_lock, so we can check 4110 // that we do not remove thread without safepoint code notice 4111 { MutexLocker ml(Threads_lock); 4112 4113 assert(includes(p), "p must be present"); 4114 4115 JavaThread* current = _thread_list; 4116 JavaThread* prev = NULL; 4117 4118 while (current != p) { 4119 prev = current; 4120 current = current->next(); 4121 } 4122 4123 if (prev) { 4124 prev->set_next(current->next()); 4125 } else { 4126 _thread_list = p->next(); 4127 } 4128 _number_of_threads--; 4129 oop threadObj = p->threadObj(); 4130 bool daemon = true; 4131 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4132 _number_of_non_daemon_threads--; 4133 daemon = false; 4134 4135 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4136 // on destroy_vm will wake up. 4137 if (number_of_non_daemon_threads() == 1) 4138 Threads_lock->notify_all(); 4139 } 4140 ThreadService::remove_thread(p, daemon); 4141 4142 // Make sure that safepoint code disregard this thread. This is needed since 4143 // the thread might mess around with locks after this point. This can cause it 4144 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4145 // of this thread since it is removed from the queue. 4146 p->set_terminated_value(); 4147 4148 // Now, this thread is not visible to safepoint 4149 p->set_safepoint_visible(false); 4150 // once the thread becomes safepoint invisible, we can not use its per-thread 4151 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4152 // to release its per-thread recorder here. 4153 MemTracker::thread_exiting(p); 4154 } // unlock Threads_lock 4155 4156 // Since Events::log uses a lock, we grab it outside the Threads_lock 4157 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4158} 4159 4160// Threads_lock must be held when this is called (or must be called during a safepoint) 4161bool Threads::includes(JavaThread* p) { 4162 assert(Threads_lock->is_locked(), "sanity check"); 4163 ALL_JAVA_THREADS(q) { 4164 if (q == p ) { 4165 return true; 4166 } 4167 } 4168 return false; 4169} 4170 4171// Operations on the Threads list for GC. These are not explicitly locked, 4172// but the garbage collector must provide a safe context for them to run. 4173// In particular, these things should never be called when the Threads_lock 4174// is held by some other thread. (Note: the Safepoint abstraction also 4175// uses the Threads_lock to gurantee this property. It also makes sure that 4176// all threads gets blocked when exiting or starting). 4177 4178void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4179 ALL_JAVA_THREADS(p) { 4180 p->oops_do(f, cld_f, cf); 4181 } 4182 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4183} 4184 4185void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4186 // Introduce a mechanism allowing parallel threads to claim threads as 4187 // root groups. Overhead should be small enough to use all the time, 4188 // even in sequential code. 4189 SharedHeap* sh = SharedHeap::heap(); 4190 // Cannot yet substitute active_workers for n_par_threads 4191 // because of G1CollectedHeap::verify() use of 4192 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4193 // turn off parallelism in process_strong_roots while active_workers 4194 // is being used for parallelism elsewhere. 4195 bool is_par = sh->n_par_threads() > 0; 4196 assert(!is_par || 4197 (SharedHeap::heap()->n_par_threads() == 4198 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4199 int cp = SharedHeap::heap()->strong_roots_parity(); 4200 ALL_JAVA_THREADS(p) { 4201 if (p->claim_oops_do(is_par, cp)) { 4202 p->oops_do(f, cld_f, cf); 4203 } 4204 } 4205 VMThread* vmt = VMThread::vm_thread(); 4206 if (vmt->claim_oops_do(is_par, cp)) { 4207 vmt->oops_do(f, cld_f, cf); 4208 } 4209} 4210 4211#if INCLUDE_ALL_GCS 4212// Used by ParallelScavenge 4213void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4214 ALL_JAVA_THREADS(p) { 4215 q->enqueue(new ThreadRootsTask(p)); 4216 } 4217 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4218} 4219 4220// Used by Parallel Old 4221void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4222 ALL_JAVA_THREADS(p) { 4223 q->enqueue(new ThreadRootsMarkingTask(p)); 4224 } 4225 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4226} 4227#endif // INCLUDE_ALL_GCS 4228 4229void Threads::nmethods_do(CodeBlobClosure* cf) { 4230 ALL_JAVA_THREADS(p) { 4231 p->nmethods_do(cf); 4232 } 4233 VMThread::vm_thread()->nmethods_do(cf); 4234} 4235 4236void Threads::metadata_do(void f(Metadata*)) { 4237 ALL_JAVA_THREADS(p) { 4238 p->metadata_do(f); 4239 } 4240} 4241 4242void Threads::gc_epilogue() { 4243 ALL_JAVA_THREADS(p) { 4244 p->gc_epilogue(); 4245 } 4246} 4247 4248void Threads::gc_prologue() { 4249 ALL_JAVA_THREADS(p) { 4250 p->gc_prologue(); 4251 } 4252} 4253 4254void Threads::deoptimized_wrt_marked_nmethods() { 4255 ALL_JAVA_THREADS(p) { 4256 p->deoptimized_wrt_marked_nmethods(); 4257 } 4258} 4259 4260 4261// Get count Java threads that are waiting to enter the specified monitor. 4262GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4263 address monitor, bool doLock) { 4264 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4265 "must grab Threads_lock or be at safepoint"); 4266 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4267 4268 int i = 0; 4269 { 4270 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4271 ALL_JAVA_THREADS(p) { 4272 if (p->is_Compiler_thread()) continue; 4273 4274 address pending = (address)p->current_pending_monitor(); 4275 if (pending == monitor) { // found a match 4276 if (i < count) result->append(p); // save the first count matches 4277 i++; 4278 } 4279 } 4280 } 4281 return result; 4282} 4283 4284 4285JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4286 assert(doLock || 4287 Threads_lock->owned_by_self() || 4288 SafepointSynchronize::is_at_safepoint(), 4289 "must grab Threads_lock or be at safepoint"); 4290 4291 // NULL owner means not locked so we can skip the search 4292 if (owner == NULL) return NULL; 4293 4294 { 4295 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4296 ALL_JAVA_THREADS(p) { 4297 // first, see if owner is the address of a Java thread 4298 if (owner == (address)p) return p; 4299 } 4300 } 4301 // Cannot assert on lack of success here since this function may be 4302 // used by code that is trying to report useful problem information 4303 // like deadlock detection. 4304 if (UseHeavyMonitors) return NULL; 4305 4306 // 4307 // If we didn't find a matching Java thread and we didn't force use of 4308 // heavyweight monitors, then the owner is the stack address of the 4309 // Lock Word in the owning Java thread's stack. 4310 // 4311 JavaThread* the_owner = NULL; 4312 { 4313 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4314 ALL_JAVA_THREADS(q) { 4315 if (q->is_lock_owned(owner)) { 4316 the_owner = q; 4317 break; 4318 } 4319 } 4320 } 4321 // cannot assert on lack of success here; see above comment 4322 return the_owner; 4323} 4324 4325// Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4326void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4327 char buf[32]; 4328 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4329 4330 st->print_cr("Full thread dump %s (%s %s):", 4331 Abstract_VM_Version::vm_name(), 4332 Abstract_VM_Version::vm_release(), 4333 Abstract_VM_Version::vm_info_string() 4334 ); 4335 st->cr(); 4336 4337#if INCLUDE_ALL_GCS 4338 // Dump concurrent locks 4339 ConcurrentLocksDump concurrent_locks; 4340 if (print_concurrent_locks) { 4341 concurrent_locks.dump_at_safepoint(); 4342 } 4343#endif // INCLUDE_ALL_GCS 4344 4345 ALL_JAVA_THREADS(p) { 4346 ResourceMark rm; 4347 p->print_on(st); 4348 if (print_stacks) { 4349 if (internal_format) { 4350 p->trace_stack(); 4351 } else { 4352 p->print_stack_on(st); 4353 } 4354 } 4355 st->cr(); 4356#if INCLUDE_ALL_GCS 4357 if (print_concurrent_locks) { 4358 concurrent_locks.print_locks_on(p, st); 4359 } 4360#endif // INCLUDE_ALL_GCS 4361 } 4362 4363 VMThread::vm_thread()->print_on(st); 4364 st->cr(); 4365 Universe::heap()->print_gc_threads_on(st); 4366 WatcherThread* wt = WatcherThread::watcher_thread(); 4367 if (wt != NULL) { 4368 wt->print_on(st); 4369 st->cr(); 4370 } 4371 CompileBroker::print_compiler_threads_on(st); 4372 st->flush(); 4373} 4374 4375// Threads::print_on_error() is called by fatal error handler. It's possible 4376// that VM is not at safepoint and/or current thread is inside signal handler. 4377// Don't print stack trace, as the stack may not be walkable. Don't allocate 4378// memory (even in resource area), it might deadlock the error handler. 4379void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4380 bool found_current = false; 4381 st->print_cr("Java Threads: ( => current thread )"); 4382 ALL_JAVA_THREADS(thread) { 4383 bool is_current = (current == thread); 4384 found_current = found_current || is_current; 4385 4386 st->print("%s", is_current ? "=>" : " "); 4387 4388 st->print(PTR_FORMAT, thread); 4389 st->print(" "); 4390 thread->print_on_error(st, buf, buflen); 4391 st->cr(); 4392 } 4393 st->cr(); 4394 4395 st->print_cr("Other Threads:"); 4396 if (VMThread::vm_thread()) { 4397 bool is_current = (current == VMThread::vm_thread()); 4398 found_current = found_current || is_current; 4399 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4400 4401 st->print(PTR_FORMAT, VMThread::vm_thread()); 4402 st->print(" "); 4403 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4404 st->cr(); 4405 } 4406 WatcherThread* wt = WatcherThread::watcher_thread(); 4407 if (wt != NULL) { 4408 bool is_current = (current == wt); 4409 found_current = found_current || is_current; 4410 st->print("%s", is_current ? "=>" : " "); 4411 4412 st->print(PTR_FORMAT, wt); 4413 st->print(" "); 4414 wt->print_on_error(st, buf, buflen); 4415 st->cr(); 4416 } 4417 if (!found_current) { 4418 st->cr(); 4419 st->print("=>" PTR_FORMAT " (exited) ", current); 4420 current->print_on_error(st, buf, buflen); 4421 st->cr(); 4422 } 4423} 4424 4425// Internal SpinLock and Mutex 4426// Based on ParkEvent 4427 4428// Ad-hoc mutual exclusion primitives: SpinLock and Mux 4429// 4430// We employ SpinLocks _only for low-contention, fixed-length 4431// short-duration critical sections where we're concerned 4432// about native mutex_t or HotSpot Mutex:: latency. 4433// The mux construct provides a spin-then-block mutual exclusion 4434// mechanism. 4435// 4436// Testing has shown that contention on the ListLock guarding gFreeList 4437// is common. If we implement ListLock as a simple SpinLock it's common 4438// for the JVM to devolve to yielding with little progress. This is true 4439// despite the fact that the critical sections protected by ListLock are 4440// extremely short. 4441// 4442// TODO-FIXME: ListLock should be of type SpinLock. 4443// We should make this a 1st-class type, integrated into the lock 4444// hierarchy as leaf-locks. Critically, the SpinLock structure 4445// should have sufficient padding to avoid false-sharing and excessive 4446// cache-coherency traffic. 4447 4448 4449typedef volatile int SpinLockT ; 4450 4451void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4452 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4453 return ; // normal fast-path return 4454 } 4455 4456 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4457 TEVENT (SpinAcquire - ctx) ; 4458 int ctr = 0 ; 4459 int Yields = 0 ; 4460 for (;;) { 4461 while (*adr != 0) { 4462 ++ctr ; 4463 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4464 if (Yields > 5) { 4465 // Consider using a simple NakedSleep() instead. 4466 // Then SpinAcquire could be called by non-JVM threads 4467 Thread::current()->_ParkEvent->park(1) ; 4468 } else { 4469 os::NakedYield() ; 4470 ++Yields ; 4471 } 4472 } else { 4473 SpinPause() ; 4474 } 4475 } 4476 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4477 } 4478} 4479 4480void Thread::SpinRelease (volatile int * adr) { 4481 assert (*adr != 0, "invariant") ; 4482 OrderAccess::fence() ; // guarantee at least release consistency. 4483 // Roach-motel semantics. 4484 // It's safe if subsequent LDs and STs float "up" into the critical section, 4485 // but prior LDs and STs within the critical section can't be allowed 4486 // to reorder or float past the ST that releases the lock. 4487 *adr = 0 ; 4488} 4489 4490// muxAcquire and muxRelease: 4491// 4492// * muxAcquire and muxRelease support a single-word lock-word construct. 4493// The LSB of the word is set IFF the lock is held. 4494// The remainder of the word points to the head of a singly-linked list 4495// of threads blocked on the lock. 4496// 4497// * The current implementation of muxAcquire-muxRelease uses its own 4498// dedicated Thread._MuxEvent instance. If we're interested in 4499// minimizing the peak number of extant ParkEvent instances then 4500// we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4501// as certain invariants were satisfied. Specifically, care would need 4502// to be taken with regards to consuming unpark() "permits". 4503// A safe rule of thumb is that a thread would never call muxAcquire() 4504// if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4505// park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4506// consume an unpark() permit intended for monitorenter, for instance. 4507// One way around this would be to widen the restricted-range semaphore 4508// implemented in park(). Another alternative would be to provide 4509// multiple instances of the PlatformEvent() for each thread. One 4510// instance would be dedicated to muxAcquire-muxRelease, for instance. 4511// 4512// * Usage: 4513// -- Only as leaf locks 4514// -- for short-term locking only as muxAcquire does not perform 4515// thread state transitions. 4516// 4517// Alternatives: 4518// * We could implement muxAcquire and muxRelease with MCS or CLH locks 4519// but with parking or spin-then-park instead of pure spinning. 4520// * Use Taura-Oyama-Yonenzawa locks. 4521// * It's possible to construct a 1-0 lock if we encode the lockword as 4522// (List,LockByte). Acquire will CAS the full lockword while Release 4523// will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4524// acquiring threads use timers (ParkTimed) to detect and recover from 4525// the stranding window. Thread/Node structures must be aligned on 256-byte 4526// boundaries by using placement-new. 4527// * Augment MCS with advisory back-link fields maintained with CAS(). 4528// Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4529// The validity of the backlinks must be ratified before we trust the value. 4530// If the backlinks are invalid the exiting thread must back-track through the 4531// the forward links, which are always trustworthy. 4532// * Add a successor indication. The LockWord is currently encoded as 4533// (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4534// to provide the usual futile-wakeup optimization. 4535// See RTStt for details. 4536// * Consider schedctl.sc_nopreempt to cover the critical section. 4537// 4538 4539 4540typedef volatile intptr_t MutexT ; // Mux Lock-word 4541enum MuxBits { LOCKBIT = 1 } ; 4542 4543void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4544 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4545 if (w == 0) return ; 4546 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4547 return ; 4548 } 4549 4550 TEVENT (muxAcquire - Contention) ; 4551 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4552 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4553 for (;;) { 4554 int its = (os::is_MP() ? 100 : 0) + 1 ; 4555 4556 // Optional spin phase: spin-then-park strategy 4557 while (--its >= 0) { 4558 w = *Lock ; 4559 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4560 return ; 4561 } 4562 } 4563 4564 Self->reset() ; 4565 Self->OnList = intptr_t(Lock) ; 4566 // The following fence() isn't _strictly necessary as the subsequent 4567 // CAS() both serializes execution and ratifies the fetched *Lock value. 4568 OrderAccess::fence(); 4569 for (;;) { 4570 w = *Lock ; 4571 if ((w & LOCKBIT) == 0) { 4572 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4573 Self->OnList = 0 ; // hygiene - allows stronger asserts 4574 return ; 4575 } 4576 continue ; // Interference -- *Lock changed -- Just retry 4577 } 4578 assert (w & LOCKBIT, "invariant") ; 4579 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4580 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4581 } 4582 4583 while (Self->OnList != 0) { 4584 Self->park() ; 4585 } 4586 } 4587} 4588 4589void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4590 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4591 if (w == 0) return ; 4592 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4593 return ; 4594 } 4595 4596 TEVENT (muxAcquire - Contention) ; 4597 ParkEvent * ReleaseAfter = NULL ; 4598 if (ev == NULL) { 4599 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4600 } 4601 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4602 for (;;) { 4603 guarantee (ev->OnList == 0, "invariant") ; 4604 int its = (os::is_MP() ? 100 : 0) + 1 ; 4605 4606 // Optional spin phase: spin-then-park strategy 4607 while (--its >= 0) { 4608 w = *Lock ; 4609 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4610 if (ReleaseAfter != NULL) { 4611 ParkEvent::Release (ReleaseAfter) ; 4612 } 4613 return ; 4614 } 4615 } 4616 4617 ev->reset() ; 4618 ev->OnList = intptr_t(Lock) ; 4619 // The following fence() isn't _strictly necessary as the subsequent 4620 // CAS() both serializes execution and ratifies the fetched *Lock value. 4621 OrderAccess::fence(); 4622 for (;;) { 4623 w = *Lock ; 4624 if ((w & LOCKBIT) == 0) { 4625 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4626 ev->OnList = 0 ; 4627 // We call ::Release while holding the outer lock, thus 4628 // artificially lengthening the critical section. 4629 // Consider deferring the ::Release() until the subsequent unlock(), 4630 // after we've dropped the outer lock. 4631 if (ReleaseAfter != NULL) { 4632 ParkEvent::Release (ReleaseAfter) ; 4633 } 4634 return ; 4635 } 4636 continue ; // Interference -- *Lock changed -- Just retry 4637 } 4638 assert (w & LOCKBIT, "invariant") ; 4639 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4640 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4641 } 4642 4643 while (ev->OnList != 0) { 4644 ev->park() ; 4645 } 4646 } 4647} 4648 4649// Release() must extract a successor from the list and then wake that thread. 4650// It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4651// similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4652// Release() would : 4653// (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4654// (B) Extract a successor from the private list "in-hand" 4655// (C) attempt to CAS() the residual back into *Lock over null. 4656// If there were any newly arrived threads and the CAS() would fail. 4657// In that case Release() would detach the RATs, re-merge the list in-hand 4658// with the RATs and repeat as needed. Alternately, Release() might 4659// detach and extract a successor, but then pass the residual list to the wakee. 4660// The wakee would be responsible for reattaching and remerging before it 4661// competed for the lock. 4662// 4663// Both "pop" and DMR are immune from ABA corruption -- there can be 4664// multiple concurrent pushers, but only one popper or detacher. 4665// This implementation pops from the head of the list. This is unfair, 4666// but tends to provide excellent throughput as hot threads remain hot. 4667// (We wake recently run threads first). 4668 4669void Thread::muxRelease (volatile intptr_t * Lock) { 4670 for (;;) { 4671 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4672 assert (w & LOCKBIT, "invariant") ; 4673 if (w == LOCKBIT) return ; 4674 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4675 assert (List != NULL, "invariant") ; 4676 assert (List->OnList == intptr_t(Lock), "invariant") ; 4677 ParkEvent * nxt = List->ListNext ; 4678 4679 // The following CAS() releases the lock and pops the head element. 4680 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4681 continue ; 4682 } 4683 List->OnList = 0 ; 4684 OrderAccess::fence() ; 4685 List->unpark () ; 4686 return ; 4687 } 4688} 4689 4690 4691void Threads::verify() { 4692 ALL_JAVA_THREADS(p) { 4693 p->verify(); 4694 } 4695 VMThread* thread = VMThread::vm_thread(); 4696 if (thread != NULL) thread->verify(); 4697} 4698