thread.cpp revision 3719:c3e799c37717
10SN/A/* 2157SN/A * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved. 30SN/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 40SN/A * 50SN/A * This code is free software; you can redistribute it and/or modify it 60SN/A * under the terms of the GNU General Public License version 2 only, as 7157SN/A * published by the Free Software Foundation. 80SN/A * 9157SN/A * This code is distributed in the hope that it will be useful, but WITHOUT 100SN/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 110SN/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 120SN/A * version 2 for more details (a copy is included in the LICENSE file that 130SN/A * accompanied this code). 140SN/A * 150SN/A * You should have received a copy of the GNU General Public License version 160SN/A * 2 along with this work; if not, write to the Free Software Foundation, 170SN/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 180SN/A * 190SN/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 200SN/A * or visit www.oracle.com if you need additional information or have any 21157SN/A * questions. 22157SN/A * 23157SN/A */ 240SN/A 250SN/A#include "precompiled.hpp" 260SN/A#include "classfile/classLoader.hpp" 270SN/A#include "classfile/javaClasses.hpp" 280SN/A#include "classfile/systemDictionary.hpp" 290SN/A#include "classfile/vmSymbols.hpp" 300SN/A#include "code/scopeDesc.hpp" 310SN/A#include "compiler/compileBroker.hpp" 320SN/A#include "interpreter/interpreter.hpp" 330SN/A#include "interpreter/linkResolver.hpp" 340SN/A#include "interpreter/oopMapCache.hpp" 350SN/A#include "jvmtifiles/jvmtiEnv.hpp" 360SN/A#include "memory/gcLocker.inline.hpp" 370SN/A#include "memory/metaspaceShared.hpp" 380SN/A#include "memory/oopFactory.hpp" 390SN/A#include "memory/universe.inline.hpp" 400SN/A#include "oops/instanceKlass.hpp" 410SN/A#include "oops/objArrayOop.hpp" 420SN/A#include "oops/oop.inline.hpp" 430SN/A#include "oops/symbol.hpp" 440SN/A#include "prims/jvm_misc.hpp" 450SN/A#include "prims/jvmtiExport.hpp" 460SN/A#include "prims/jvmtiThreadState.hpp" 470SN/A#include "prims/privilegedStack.hpp" 480SN/A#include "runtime/aprofiler.hpp" 490SN/A#include "runtime/arguments.hpp" 500SN/A#include "runtime/biasedLocking.hpp" 510SN/A#include "runtime/deoptimization.hpp" 520SN/A#include "runtime/fprofiler.hpp" 530SN/A#include "runtime/frame.inline.hpp" 540SN/A#include "runtime/init.hpp" 550SN/A#include "runtime/interfaceSupport.hpp" 560SN/A#include "runtime/java.hpp" 570SN/A#include "runtime/javaCalls.hpp" 580SN/A#include "runtime/jniPeriodicChecker.hpp" 590SN/A#include "runtime/memprofiler.hpp" 600SN/A#include "runtime/mutexLocker.hpp" 610SN/A#include "runtime/objectMonitor.hpp" 620SN/A#include "runtime/osThread.hpp" 630SN/A#include "runtime/safepoint.hpp" 640SN/A#include "runtime/sharedRuntime.hpp" 650SN/A#include "runtime/statSampler.hpp" 660SN/A#include "runtime/stubRoutines.hpp" 670SN/A#include "runtime/task.hpp" 680SN/A#include "runtime/threadCritical.hpp" 690SN/A#include "runtime/threadLocalStorage.hpp" 700SN/A#include "runtime/vframe.hpp" 710SN/A#include "runtime/vframeArray.hpp" 720SN/A#include "runtime/vframe_hp.hpp" 730SN/A#include "runtime/vmThread.hpp" 740SN/A#include "runtime/vm_operations.hpp" 750SN/A#include "services/attachListener.hpp" 760SN/A#include "services/management.hpp" 770SN/A#include "services/memTracker.hpp" 780SN/A#include "services/threadService.hpp" 790SN/A#include "trace/traceEventTypes.hpp" 800SN/A#include "utilities/defaultStream.hpp" 810SN/A#include "utilities/dtrace.hpp" 82#include "utilities/events.hpp" 83#include "utilities/preserveException.hpp" 84#ifdef TARGET_OS_FAMILY_linux 85# include "os_linux.inline.hpp" 86# include "thread_linux.inline.hpp" 87#endif 88#ifdef TARGET_OS_FAMILY_solaris 89# include "os_solaris.inline.hpp" 90# include "thread_solaris.inline.hpp" 91#endif 92#ifdef TARGET_OS_FAMILY_windows 93# include "os_windows.inline.hpp" 94# include "thread_windows.inline.hpp" 95#endif 96#ifdef TARGET_OS_FAMILY_bsd 97# include "os_bsd.inline.hpp" 98# include "thread_bsd.inline.hpp" 99#endif 100#ifndef SERIALGC 101#include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 102#include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 103#include "gc_implementation/parallelScavenge/pcTasks.hpp" 104#endif 105#ifdef COMPILER1 106#include "c1/c1_Compiler.hpp" 107#endif 108#ifdef COMPILER2 109#include "opto/c2compiler.hpp" 110#include "opto/idealGraphPrinter.hpp" 111#endif 112 113#ifdef DTRACE_ENABLED 114 115// Only bother with this argument setup if dtrace is available 116 117#ifndef USDT2 118HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 119HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 120HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 121 intptr_t, intptr_t, bool); 122HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 123 intptr_t, intptr_t, bool); 124 125#define DTRACE_THREAD_PROBE(probe, javathread) \ 126 { \ 127 ResourceMark rm(this); \ 128 int len = 0; \ 129 const char* name = (javathread)->get_thread_name(); \ 130 len = strlen(name); \ 131 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 132 name, len, \ 133 java_lang_Thread::thread_id((javathread)->threadObj()), \ 134 (javathread)->osthread()->thread_id(), \ 135 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 136 } 137 138#else /* USDT2 */ 139 140#define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START 141#define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP 142 143#define DTRACE_THREAD_PROBE(probe, javathread) \ 144 { \ 145 ResourceMark rm(this); \ 146 int len = 0; \ 147 const char* name = (javathread)->get_thread_name(); \ 148 len = strlen(name); \ 149 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 150 (char *) name, len, \ 151 java_lang_Thread::thread_id((javathread)->threadObj()), \ 152 (uintptr_t) (javathread)->osthread()->thread_id(), \ 153 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 154 } 155 156#endif /* USDT2 */ 157 158#else // ndef DTRACE_ENABLED 159 160#define DTRACE_THREAD_PROBE(probe, javathread) 161 162#endif // ndef DTRACE_ENABLED 163 164 165// Class hierarchy 166// - Thread 167// - VMThread 168// - WatcherThread 169// - ConcurrentMarkSweepThread 170// - JavaThread 171// - CompilerThread 172 173// ======= Thread ======== 174// Support for forcing alignment of thread objects for biased locking 175void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 176 if (UseBiasedLocking) { 177 const int alignment = markOopDesc::biased_lock_alignment; 178 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 179 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 180 : os::malloc(aligned_size, flags, CURRENT_PC); 181 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 182 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 183 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 184 "JavaThread alignment code overflowed allocated storage"); 185 if (TraceBiasedLocking) { 186 if (aligned_addr != real_malloc_addr) 187 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 188 real_malloc_addr, aligned_addr); 189 } 190 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 191 return aligned_addr; 192 } else { 193 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 194 : os::malloc(size, flags, CURRENT_PC); 195 } 196} 197 198void Thread::operator delete(void* p) { 199 if (UseBiasedLocking) { 200 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 201 FreeHeap(real_malloc_addr, mtThread); 202 } else { 203 FreeHeap(p, mtThread); 204 } 205} 206 207 208// Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 209// JavaThread 210 211 212Thread::Thread() { 213 // stack and get_thread 214 set_stack_base(NULL); 215 set_stack_size(0); 216 set_self_raw_id(0); 217 set_lgrp_id(-1); 218 219 // allocated data structures 220 set_osthread(NULL); 221 set_resource_area(new (mtThread)ResourceArea()); 222 set_handle_area(new (mtThread) HandleArea(NULL)); 223 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(300, 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 set_trace_buffer(NULL); 243 _vm_operation_started_count = 0; 244 _vm_operation_completed_count = 0; 245 _current_pending_monitor = NULL; 246 _current_pending_monitor_is_from_java = true; 247 _current_waiting_monitor = NULL; 248 _num_nested_signal = 0; 249 omFreeList = NULL ; 250 omFreeCount = 0 ; 251 omFreeProvision = 32 ; 252 omInUseList = NULL ; 253 omInUseCount = 0 ; 254 255#ifdef ASSERT 256 _visited_for_critical_count = false; 257#endif 258 259 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 260 _suspend_flags = 0; 261 262 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 263 _hashStateX = os::random() ; 264 _hashStateY = 842502087 ; 265 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 266 _hashStateW = 273326509 ; 267 268 _OnTrap = 0 ; 269 _schedctl = NULL ; 270 _Stalled = 0 ; 271 _TypeTag = 0x2BAD ; 272 273 // Many of the following fields are effectively final - immutable 274 // Note that nascent threads can't use the Native Monitor-Mutex 275 // construct until the _MutexEvent is initialized ... 276 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 277 // we might instead use a stack of ParkEvents that we could provision on-demand. 278 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 279 // and ::Release() 280 _ParkEvent = ParkEvent::Allocate (this) ; 281 _SleepEvent = ParkEvent::Allocate (this) ; 282 _MutexEvent = ParkEvent::Allocate (this) ; 283 _MuxEvent = ParkEvent::Allocate (this) ; 284 285#ifdef CHECK_UNHANDLED_OOPS 286 if (CheckUnhandledOops) { 287 _unhandled_oops = new UnhandledOops(this); 288 } 289#endif // CHECK_UNHANDLED_OOPS 290#ifdef ASSERT 291 if (UseBiasedLocking) { 292 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 293 assert(this == _real_malloc_address || 294 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 295 "bug in forced alignment of thread objects"); 296 } 297#endif /* ASSERT */ 298} 299 300void Thread::initialize_thread_local_storage() { 301 // Note: Make sure this method only calls 302 // non-blocking operations. Otherwise, it might not work 303 // with the thread-startup/safepoint interaction. 304 305 // During Java thread startup, safepoint code should allow this 306 // method to complete because it may need to allocate memory to 307 // store information for the new thread. 308 309 // initialize structure dependent on thread local storage 310 ThreadLocalStorage::set_thread(this); 311} 312 313void Thread::record_stack_base_and_size() { 314 set_stack_base(os::current_stack_base()); 315 set_stack_size(os::current_stack_size()); 316 // CR 7190089: on Solaris, primordial thread's stack is adjusted 317 // in initialize_thread(). Without the adjustment, stack size is 318 // incorrect if stack is set to unlimited (ulimit -s unlimited). 319 // So far, only Solaris has real implementation of initialize_thread(). 320 // 321 // set up any platform-specific state. 322 os::initialize_thread(this); 323 324 // record thread's native stack, stack grows downward 325 if (MemTracker::is_on()) { 326 address stack_low_addr = stack_base() - stack_size(); 327 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 328 CURRENT_PC); 329 } 330} 331 332 333Thread::~Thread() { 334 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 335 ObjectSynchronizer::omFlush (this) ; 336 337 // stack_base can be NULL if the thread is never started or exited before 338 // record_stack_base_and_size called. Although, we would like to ensure 339 // that all started threads do call record_stack_base_and_size(), there is 340 // not proper way to enforce that. 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 } 345 346 // deallocate data structures 347 delete resource_area(); 348 // since the handle marks are using the handle area, we have to deallocated the root 349 // handle mark before deallocating the thread's handle area, 350 assert(last_handle_mark() != NULL, "check we have an element"); 351 delete last_handle_mark(); 352 assert(last_handle_mark() == NULL, "check we have reached the end"); 353 354 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 355 // We NULL out the fields for good hygiene. 356 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 357 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 358 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 359 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 360 361 delete handle_area(); 362 delete metadata_handles(); 363 364 // osthread() can be NULL, if creation of thread failed. 365 if (osthread() != NULL) os::free_thread(osthread()); 366 367 delete _SR_lock; 368 369 // clear thread local storage if the Thread is deleting itself 370 if (this == Thread::current()) { 371 ThreadLocalStorage::set_thread(NULL); 372 } else { 373 // In the case where we're not the current thread, invalidate all the 374 // caches in case some code tries to get the current thread or the 375 // thread that was destroyed, and gets stale information. 376 ThreadLocalStorage::invalidate_all(); 377 } 378 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 379} 380 381// NOTE: dummy function for assertion purpose. 382void Thread::run() { 383 ShouldNotReachHere(); 384} 385 386#ifdef ASSERT 387// Private method to check for dangling thread pointer 388void check_for_dangling_thread_pointer(Thread *thread) { 389 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 390 "possibility of dangling Thread pointer"); 391} 392#endif 393 394 395#ifndef PRODUCT 396// Tracing method for basic thread operations 397void Thread::trace(const char* msg, const Thread* const thread) { 398 if (!TraceThreadEvents) return; 399 ResourceMark rm; 400 ThreadCritical tc; 401 const char *name = "non-Java thread"; 402 int prio = -1; 403 if (thread->is_Java_thread() 404 && !thread->is_Compiler_thread()) { 405 // The Threads_lock must be held to get information about 406 // this thread but may not be in some situations when 407 // tracing thread events. 408 bool release_Threads_lock = false; 409 if (!Threads_lock->owned_by_self()) { 410 Threads_lock->lock(); 411 release_Threads_lock = true; 412 } 413 JavaThread* jt = (JavaThread *)thread; 414 name = (char *)jt->get_thread_name(); 415 oop thread_oop = jt->threadObj(); 416 if (thread_oop != NULL) { 417 prio = java_lang_Thread::priority(thread_oop); 418 } 419 if (release_Threads_lock) { 420 Threads_lock->unlock(); 421 } 422 } 423 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 424} 425#endif 426 427 428ThreadPriority Thread::get_priority(const Thread* const thread) { 429 trace("get priority", thread); 430 ThreadPriority priority; 431 // Can return an error! 432 (void)os::get_priority(thread, priority); 433 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 434 return priority; 435} 436 437void Thread::set_priority(Thread* thread, ThreadPriority priority) { 438 trace("set priority", thread); 439 debug_only(check_for_dangling_thread_pointer(thread);) 440 // Can return an error! 441 (void)os::set_priority(thread, priority); 442} 443 444 445void Thread::start(Thread* thread) { 446 trace("start", thread); 447 // Start is different from resume in that its safety is guaranteed by context or 448 // being called from a Java method synchronized on the Thread object. 449 if (!DisableStartThread) { 450 if (thread->is_Java_thread()) { 451 // Initialize the thread state to RUNNABLE before starting this thread. 452 // Can not set it after the thread started because we do not know the 453 // exact thread state at that time. It could be in MONITOR_WAIT or 454 // in SLEEPING or some other state. 455 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 456 java_lang_Thread::RUNNABLE); 457 } 458 os::start_thread(thread); 459 } 460} 461 462// Enqueue a VM_Operation to do the job for us - sometime later 463void Thread::send_async_exception(oop java_thread, oop java_throwable) { 464 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 465 VMThread::execute(vm_stop); 466} 467 468 469// 470// Check if an external suspend request has completed (or has been 471// cancelled). Returns true if the thread is externally suspended and 472// false otherwise. 473// 474// The bits parameter returns information about the code path through 475// the routine. Useful for debugging: 476// 477// set in is_ext_suspend_completed(): 478// 0x00000001 - routine was entered 479// 0x00000010 - routine return false at end 480// 0x00000100 - thread exited (return false) 481// 0x00000200 - suspend request cancelled (return false) 482// 0x00000400 - thread suspended (return true) 483// 0x00001000 - thread is in a suspend equivalent state (return true) 484// 0x00002000 - thread is native and walkable (return true) 485// 0x00004000 - thread is native_trans and walkable (needed retry) 486// 487// set in wait_for_ext_suspend_completion(): 488// 0x00010000 - routine was entered 489// 0x00020000 - suspend request cancelled before loop (return false) 490// 0x00040000 - thread suspended before loop (return true) 491// 0x00080000 - suspend request cancelled in loop (return false) 492// 0x00100000 - thread suspended in loop (return true) 493// 0x00200000 - suspend not completed during retry loop (return false) 494// 495 496// Helper class for tracing suspend wait debug bits. 497// 498// 0x00000100 indicates that the target thread exited before it could 499// self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 500// 0x00080000 each indicate a cancelled suspend request so they don't 501// count as wait failures either. 502#define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 503 504class TraceSuspendDebugBits : public StackObj { 505 private: 506 JavaThread * jt; 507 bool is_wait; 508 bool called_by_wait; // meaningful when !is_wait 509 uint32_t * bits; 510 511 public: 512 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 513 uint32_t *_bits) { 514 jt = _jt; 515 is_wait = _is_wait; 516 called_by_wait = _called_by_wait; 517 bits = _bits; 518 } 519 520 ~TraceSuspendDebugBits() { 521 if (!is_wait) { 522#if 1 523 // By default, don't trace bits for is_ext_suspend_completed() calls. 524 // That trace is very chatty. 525 return; 526#else 527 if (!called_by_wait) { 528 // If tracing for is_ext_suspend_completed() is enabled, then only 529 // trace calls to it from wait_for_ext_suspend_completion() 530 return; 531 } 532#endif 533 } 534 535 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 536 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 537 MutexLocker ml(Threads_lock); // needed for get_thread_name() 538 ResourceMark rm; 539 540 tty->print_cr( 541 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 542 jt->get_thread_name(), *bits); 543 544 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 545 } 546 } 547 } 548}; 549#undef DEBUG_FALSE_BITS 550 551 552bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 553 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 554 555 bool did_trans_retry = false; // only do thread_in_native_trans retry once 556 bool do_trans_retry; // flag to force the retry 557 558 *bits |= 0x00000001; 559 560 do { 561 do_trans_retry = false; 562 563 if (is_exiting()) { 564 // Thread is in the process of exiting. This is always checked 565 // first to reduce the risk of dereferencing a freed JavaThread. 566 *bits |= 0x00000100; 567 return false; 568 } 569 570 if (!is_external_suspend()) { 571 // Suspend request is cancelled. This is always checked before 572 // is_ext_suspended() to reduce the risk of a rogue resume 573 // confusing the thread that made the suspend request. 574 *bits |= 0x00000200; 575 return false; 576 } 577 578 if (is_ext_suspended()) { 579 // thread is suspended 580 *bits |= 0x00000400; 581 return true; 582 } 583 584 // Now that we no longer do hard suspends of threads running 585 // native code, the target thread can be changing thread state 586 // while we are in this routine: 587 // 588 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 589 // 590 // We save a copy of the thread state as observed at this moment 591 // and make our decision about suspend completeness based on the 592 // copy. This closes the race where the thread state is seen as 593 // _thread_in_native_trans in the if-thread_blocked check, but is 594 // seen as _thread_blocked in if-thread_in_native_trans check. 595 JavaThreadState save_state = thread_state(); 596 597 if (save_state == _thread_blocked && is_suspend_equivalent()) { 598 // If the thread's state is _thread_blocked and this blocking 599 // condition is known to be equivalent to a suspend, then we can 600 // consider the thread to be externally suspended. This means that 601 // the code that sets _thread_blocked has been modified to do 602 // self-suspension if the blocking condition releases. We also 603 // used to check for CONDVAR_WAIT here, but that is now covered by 604 // the _thread_blocked with self-suspension check. 605 // 606 // Return true since we wouldn't be here unless there was still an 607 // external suspend request. 608 *bits |= 0x00001000; 609 return true; 610 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 611 // Threads running native code will self-suspend on native==>VM/Java 612 // transitions. If its stack is walkable (should always be the case 613 // unless this function is called before the actual java_suspend() 614 // call), then the wait is done. 615 *bits |= 0x00002000; 616 return true; 617 } else if (!called_by_wait && !did_trans_retry && 618 save_state == _thread_in_native_trans && 619 frame_anchor()->walkable()) { 620 // The thread is transitioning from thread_in_native to another 621 // thread state. check_safepoint_and_suspend_for_native_trans() 622 // will force the thread to self-suspend. If it hasn't gotten 623 // there yet we may have caught the thread in-between the native 624 // code check above and the self-suspend. Lucky us. If we were 625 // called by wait_for_ext_suspend_completion(), then it 626 // will be doing the retries so we don't have to. 627 // 628 // Since we use the saved thread state in the if-statement above, 629 // there is a chance that the thread has already transitioned to 630 // _thread_blocked by the time we get here. In that case, we will 631 // make a single unnecessary pass through the logic below. This 632 // doesn't hurt anything since we still do the trans retry. 633 634 *bits |= 0x00004000; 635 636 // Once the thread leaves thread_in_native_trans for another 637 // thread state, we break out of this retry loop. We shouldn't 638 // need this flag to prevent us from getting back here, but 639 // sometimes paranoia is good. 640 did_trans_retry = true; 641 642 // We wait for the thread to transition to a more usable state. 643 for (int i = 1; i <= SuspendRetryCount; i++) { 644 // We used to do an "os::yield_all(i)" call here with the intention 645 // that yielding would increase on each retry. However, the parameter 646 // is ignored on Linux which means the yield didn't scale up. Waiting 647 // on the SR_lock below provides a much more predictable scale up for 648 // the delay. It also provides a simple/direct point to check for any 649 // safepoint requests from the VMThread 650 651 // temporarily drops SR_lock while doing wait with safepoint check 652 // (if we're a JavaThread - the WatcherThread can also call this) 653 // and increase delay with each retry 654 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 655 656 // check the actual thread state instead of what we saved above 657 if (thread_state() != _thread_in_native_trans) { 658 // the thread has transitioned to another thread state so 659 // try all the checks (except this one) one more time. 660 do_trans_retry = true; 661 break; 662 } 663 } // end retry loop 664 665 666 } 667 } while (do_trans_retry); 668 669 *bits |= 0x00000010; 670 return false; 671} 672 673// 674// Wait for an external suspend request to complete (or be cancelled). 675// Returns true if the thread is externally suspended and false otherwise. 676// 677bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 678 uint32_t *bits) { 679 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 680 false /* !called_by_wait */, bits); 681 682 // local flag copies to minimize SR_lock hold time 683 bool is_suspended; 684 bool pending; 685 uint32_t reset_bits; 686 687 // set a marker so is_ext_suspend_completed() knows we are the caller 688 *bits |= 0x00010000; 689 690 // We use reset_bits to reinitialize the bits value at the top of 691 // each retry loop. This allows the caller to make use of any 692 // unused bits for their own marking purposes. 693 reset_bits = *bits; 694 695 { 696 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 697 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 698 delay, bits); 699 pending = is_external_suspend(); 700 } 701 // must release SR_lock to allow suspension to complete 702 703 if (!pending) { 704 // A cancelled suspend request is the only false return from 705 // is_ext_suspend_completed() that keeps us from entering the 706 // retry loop. 707 *bits |= 0x00020000; 708 return false; 709 } 710 711 if (is_suspended) { 712 *bits |= 0x00040000; 713 return true; 714 } 715 716 for (int i = 1; i <= retries; i++) { 717 *bits = reset_bits; // reinit to only track last retry 718 719 // We used to do an "os::yield_all(i)" call here with the intention 720 // that yielding would increase on each retry. However, the parameter 721 // is ignored on Linux which means the yield didn't scale up. Waiting 722 // on the SR_lock below provides a much more predictable scale up for 723 // the delay. It also provides a simple/direct point to check for any 724 // safepoint requests from the VMThread 725 726 { 727 MutexLocker ml(SR_lock()); 728 // wait with safepoint check (if we're a JavaThread - the WatcherThread 729 // can also call this) and increase delay with each retry 730 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 731 732 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 733 delay, bits); 734 735 // It is possible for the external suspend request to be cancelled 736 // (by a resume) before the actual suspend operation is completed. 737 // Refresh our local copy to see if we still need to wait. 738 pending = is_external_suspend(); 739 } 740 741 if (!pending) { 742 // A cancelled suspend request is the only false return from 743 // is_ext_suspend_completed() that keeps us from staying in the 744 // retry loop. 745 *bits |= 0x00080000; 746 return false; 747 } 748 749 if (is_suspended) { 750 *bits |= 0x00100000; 751 return true; 752 } 753 } // end retry loop 754 755 // thread did not suspend after all our retries 756 *bits |= 0x00200000; 757 return false; 758} 759 760#ifndef PRODUCT 761void JavaThread::record_jump(address target, address instr, const char* file, int line) { 762 763 // This should not need to be atomic as the only way for simultaneous 764 // updates is via interrupts. Even then this should be rare or non-existant 765 // and we don't care that much anyway. 766 767 int index = _jmp_ring_index; 768 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 769 _jmp_ring[index]._target = (intptr_t) target; 770 _jmp_ring[index]._instruction = (intptr_t) instr; 771 _jmp_ring[index]._file = file; 772 _jmp_ring[index]._line = line; 773} 774#endif /* PRODUCT */ 775 776// Called by flat profiler 777// Callers have already called wait_for_ext_suspend_completion 778// The assertion for that is currently too complex to put here: 779bool JavaThread::profile_last_Java_frame(frame* _fr) { 780 bool gotframe = false; 781 // self suspension saves needed state. 782 if (has_last_Java_frame() && _anchor.walkable()) { 783 *_fr = pd_last_frame(); 784 gotframe = true; 785 } 786 return gotframe; 787} 788 789void Thread::interrupt(Thread* thread) { 790 trace("interrupt", thread); 791 debug_only(check_for_dangling_thread_pointer(thread);) 792 os::interrupt(thread); 793} 794 795bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 796 trace("is_interrupted", thread); 797 debug_only(check_for_dangling_thread_pointer(thread);) 798 // Note: If clear_interrupted==false, this simply fetches and 799 // returns the value of the field osthread()->interrupted(). 800 return os::is_interrupted(thread, clear_interrupted); 801} 802 803 804// GC Support 805bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 806 jint thread_parity = _oops_do_parity; 807 if (thread_parity != strong_roots_parity) { 808 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 809 if (res == thread_parity) { 810 return true; 811 } else { 812 guarantee(res == strong_roots_parity, "Or else what?"); 813 assert(SharedHeap::heap()->workers()->active_workers() > 0, 814 "Should only fail when parallel."); 815 return false; 816 } 817 } 818 assert(SharedHeap::heap()->workers()->active_workers() > 0, 819 "Should only fail when parallel."); 820 return false; 821} 822 823void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 824 active_handles()->oops_do(f); 825 // Do oop for ThreadShadow 826 f->do_oop((oop*)&_pending_exception); 827 handle_area()->oops_do(f); 828} 829 830void Thread::nmethods_do(CodeBlobClosure* cf) { 831 // no nmethods in a generic thread... 832} 833 834void Thread::metadata_do(void f(Metadata*)) { 835 if (metadata_handles() != NULL) { 836 for (int i = 0; i< metadata_handles()->length(); i++) { 837 f(metadata_handles()->at(i)); 838 } 839 } 840} 841 842void Thread::print_on(outputStream* st) const { 843 // get_priority assumes osthread initialized 844 if (osthread() != NULL) { 845 int os_prio; 846 if (os::get_native_priority(this, &os_prio) == OS_OK) { 847 st->print("os_prio=%d ", os_prio); 848 } 849 st->print("tid=" INTPTR_FORMAT " ", this); 850 osthread()->print_on(st); 851 } 852 debug_only(if (WizardMode) print_owned_locks_on(st);) 853} 854 855// Thread::print_on_error() is called by fatal error handler. Don't use 856// any lock or allocate memory. 857void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 858 if (is_VM_thread()) st->print("VMThread"); 859 else if (is_Compiler_thread()) st->print("CompilerThread"); 860 else if (is_Java_thread()) st->print("JavaThread"); 861 else if (is_GC_task_thread()) st->print("GCTaskThread"); 862 else if (is_Watcher_thread()) st->print("WatcherThread"); 863 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 864 else st->print("Thread"); 865 866 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 867 _stack_base - _stack_size, _stack_base); 868 869 if (osthread()) { 870 st->print(" [id=%d]", osthread()->thread_id()); 871 } 872} 873 874#ifdef ASSERT 875void Thread::print_owned_locks_on(outputStream* st) const { 876 Monitor *cur = _owned_locks; 877 if (cur == NULL) { 878 st->print(" (no locks) "); 879 } else { 880 st->print_cr(" Locks owned:"); 881 while(cur) { 882 cur->print_on(st); 883 cur = cur->next(); 884 } 885 } 886} 887 888static int ref_use_count = 0; 889 890bool Thread::owns_locks_but_compiled_lock() const { 891 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 892 if (cur != Compile_lock) return true; 893 } 894 return false; 895} 896 897 898#endif 899 900#ifndef PRODUCT 901 902// The flag: potential_vm_operation notifies if this particular safepoint state could potential 903// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 904// no threads which allow_vm_block's are held 905void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 906 // Check if current thread is allowed to block at a safepoint 907 if (!(_allow_safepoint_count == 0)) 908 fatal("Possible safepoint reached by thread that does not allow it"); 909 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 910 fatal("LEAF method calling lock?"); 911 } 912 913#ifdef ASSERT 914 if (potential_vm_operation && is_Java_thread() 915 && !Universe::is_bootstrapping()) { 916 // Make sure we do not hold any locks that the VM thread also uses. 917 // This could potentially lead to deadlocks 918 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 919 // Threads_lock is special, since the safepoint synchronization will not start before this is 920 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 921 // since it is used to transfer control between JavaThreads and the VMThread 922 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first! 923 if ( (cur->allow_vm_block() && 924 cur != Threads_lock && 925 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation 926 cur != VMOperationRequest_lock && 927 cur != VMOperationQueue_lock) || 928 cur->rank() == Mutex::special) { 929 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 930 } 931 } 932 } 933 934 if (GCALotAtAllSafepoints) { 935 // We could enter a safepoint here and thus have a gc 936 InterfaceSupport::check_gc_alot(); 937 } 938#endif 939} 940#endif 941 942bool Thread::is_in_stack(address adr) const { 943 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 944 address end = os::current_stack_pointer(); 945 // Allow non Java threads to call this without stack_base 946 if (_stack_base == NULL) return true; 947 if (stack_base() >= adr && adr >= end) return true; 948 949 return false; 950} 951 952 953// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 954// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 955// used for compilation in the future. If that change is made, the need for these methods 956// should be revisited, and they should be removed if possible. 957 958bool Thread::is_lock_owned(address adr) const { 959 return on_local_stack(adr); 960} 961 962bool Thread::set_as_starting_thread() { 963 // NOTE: this must be called inside the main thread. 964 return os::create_main_thread((JavaThread*)this); 965} 966 967static void initialize_class(Symbol* class_name, TRAPS) { 968 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 969 InstanceKlass::cast(klass)->initialize(CHECK); 970} 971 972 973// Creates the initial ThreadGroup 974static Handle create_initial_thread_group(TRAPS) { 975 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 976 instanceKlassHandle klass (THREAD, k); 977 978 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 979 { 980 JavaValue result(T_VOID); 981 JavaCalls::call_special(&result, 982 system_instance, 983 klass, 984 vmSymbols::object_initializer_name(), 985 vmSymbols::void_method_signature(), 986 CHECK_NH); 987 } 988 Universe::set_system_thread_group(system_instance()); 989 990 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 991 { 992 JavaValue result(T_VOID); 993 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 994 JavaCalls::call_special(&result, 995 main_instance, 996 klass, 997 vmSymbols::object_initializer_name(), 998 vmSymbols::threadgroup_string_void_signature(), 999 system_instance, 1000 string, 1001 CHECK_NH); 1002 } 1003 return main_instance; 1004} 1005 1006// Creates the initial Thread 1007static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1008 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1009 instanceKlassHandle klass (THREAD, k); 1010 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1011 1012 java_lang_Thread::set_thread(thread_oop(), thread); 1013 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1014 thread->set_threadObj(thread_oop()); 1015 1016 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1017 1018 JavaValue result(T_VOID); 1019 JavaCalls::call_special(&result, thread_oop, 1020 klass, 1021 vmSymbols::object_initializer_name(), 1022 vmSymbols::threadgroup_string_void_signature(), 1023 thread_group, 1024 string, 1025 CHECK_NULL); 1026 return thread_oop(); 1027} 1028 1029static void call_initializeSystemClass(TRAPS) { 1030 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1031 instanceKlassHandle klass (THREAD, k); 1032 1033 JavaValue result(T_VOID); 1034 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1035 vmSymbols::void_method_signature(), CHECK); 1036} 1037 1038char java_runtime_name[128] = ""; 1039 1040// extract the JRE name from sun.misc.Version.java_runtime_name 1041static const char* get_java_runtime_name(TRAPS) { 1042 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1043 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1044 fieldDescriptor fd; 1045 bool found = k != NULL && 1046 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1047 vmSymbols::string_signature(), &fd); 1048 if (found) { 1049 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1050 if (name_oop == NULL) 1051 return NULL; 1052 const char* name = java_lang_String::as_utf8_string(name_oop, 1053 java_runtime_name, 1054 sizeof(java_runtime_name)); 1055 return name; 1056 } else { 1057 return NULL; 1058 } 1059} 1060 1061// General purpose hook into Java code, run once when the VM is initialized. 1062// The Java library method itself may be changed independently from the VM. 1063static void call_postVMInitHook(TRAPS) { 1064 Klass* k = SystemDictionary::PostVMInitHook_klass(); 1065 instanceKlassHandle klass (THREAD, k); 1066 if (klass.not_null()) { 1067 JavaValue result(T_VOID); 1068 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1069 vmSymbols::void_method_signature(), 1070 CHECK); 1071 } 1072} 1073 1074static void reset_vm_info_property(TRAPS) { 1075 // the vm info string 1076 ResourceMark rm(THREAD); 1077 const char *vm_info = VM_Version::vm_info_string(); 1078 1079 // java.lang.System class 1080 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1081 instanceKlassHandle klass (THREAD, k); 1082 1083 // setProperty arguments 1084 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1085 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1086 1087 // return value 1088 JavaValue r(T_OBJECT); 1089 1090 // public static String setProperty(String key, String value); 1091 JavaCalls::call_static(&r, 1092 klass, 1093 vmSymbols::setProperty_name(), 1094 vmSymbols::string_string_string_signature(), 1095 key_str, 1096 value_str, 1097 CHECK); 1098} 1099 1100 1101void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1102 assert(thread_group.not_null(), "thread group should be specified"); 1103 assert(threadObj() == NULL, "should only create Java thread object once"); 1104 1105 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1106 instanceKlassHandle klass (THREAD, k); 1107 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1108 1109 java_lang_Thread::set_thread(thread_oop(), this); 1110 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1111 set_threadObj(thread_oop()); 1112 1113 JavaValue result(T_VOID); 1114 if (thread_name != NULL) { 1115 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1116 // Thread gets assigned specified name and null target 1117 JavaCalls::call_special(&result, 1118 thread_oop, 1119 klass, 1120 vmSymbols::object_initializer_name(), 1121 vmSymbols::threadgroup_string_void_signature(), 1122 thread_group, // Argument 1 1123 name, // Argument 2 1124 THREAD); 1125 } else { 1126 // Thread gets assigned name "Thread-nnn" and null target 1127 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1128 JavaCalls::call_special(&result, 1129 thread_oop, 1130 klass, 1131 vmSymbols::object_initializer_name(), 1132 vmSymbols::threadgroup_runnable_void_signature(), 1133 thread_group, // Argument 1 1134 Handle(), // Argument 2 1135 THREAD); 1136 } 1137 1138 1139 if (daemon) { 1140 java_lang_Thread::set_daemon(thread_oop()); 1141 } 1142 1143 if (HAS_PENDING_EXCEPTION) { 1144 return; 1145 } 1146 1147 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1148 Handle threadObj(this, this->threadObj()); 1149 1150 JavaCalls::call_special(&result, 1151 thread_group, 1152 group, 1153 vmSymbols::add_method_name(), 1154 vmSymbols::thread_void_signature(), 1155 threadObj, // Arg 1 1156 THREAD); 1157 1158 1159} 1160 1161// NamedThread -- non-JavaThread subclasses with multiple 1162// uniquely named instances should derive from this. 1163NamedThread::NamedThread() : Thread() { 1164 _name = NULL; 1165 _processed_thread = NULL; 1166} 1167 1168NamedThread::~NamedThread() { 1169 if (_name != NULL) { 1170 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1171 _name = NULL; 1172 } 1173} 1174 1175void NamedThread::set_name(const char* format, ...) { 1176 guarantee(_name == NULL, "Only get to set name once."); 1177 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1178 guarantee(_name != NULL, "alloc failure"); 1179 va_list ap; 1180 va_start(ap, format); 1181 jio_vsnprintf(_name, max_name_len, format, ap); 1182 va_end(ap); 1183} 1184 1185// ======= WatcherThread ======== 1186 1187// The watcher thread exists to simulate timer interrupts. It should 1188// be replaced by an abstraction over whatever native support for 1189// timer interrupts exists on the platform. 1190 1191WatcherThread* WatcherThread::_watcher_thread = NULL; 1192volatile bool WatcherThread::_should_terminate = false; 1193 1194WatcherThread::WatcherThread() : Thread() { 1195 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1196 if (os::create_thread(this, os::watcher_thread)) { 1197 _watcher_thread = this; 1198 1199 // Set the watcher thread to the highest OS priority which should not be 1200 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1201 // is created. The only normal thread using this priority is the reference 1202 // handler thread, which runs for very short intervals only. 1203 // If the VMThread's priority is not lower than the WatcherThread profiling 1204 // will be inaccurate. 1205 os::set_priority(this, MaxPriority); 1206 if (!DisableStartThread) { 1207 os::start_thread(this); 1208 } 1209 } 1210} 1211 1212void WatcherThread::run() { 1213 assert(this == watcher_thread(), "just checking"); 1214 1215 this->record_stack_base_and_size(); 1216 this->initialize_thread_local_storage(); 1217 this->set_active_handles(JNIHandleBlock::allocate_block()); 1218 while(!_should_terminate) { 1219 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1220 assert(watcher_thread() == this, "thread consistency check"); 1221 1222 // Calculate how long it'll be until the next PeriodicTask work 1223 // should be done, and sleep that amount of time. 1224 size_t time_to_wait = PeriodicTask::time_to_wait(); 1225 1226 // we expect this to timeout - we only ever get unparked when 1227 // we should terminate 1228 { 1229 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1230 1231 jlong prev_time = os::javaTimeNanos(); 1232 for (;;) { 1233 int res= _SleepEvent->park(time_to_wait); 1234 if (res == OS_TIMEOUT || _should_terminate) 1235 break; 1236 // spurious wakeup of some kind 1237 jlong now = os::javaTimeNanos(); 1238 time_to_wait -= (now - prev_time) / 1000000; 1239 if (time_to_wait <= 0) 1240 break; 1241 prev_time = now; 1242 } 1243 } 1244 1245 if (is_error_reported()) { 1246 // A fatal error has happened, the error handler(VMError::report_and_die) 1247 // should abort JVM after creating an error log file. However in some 1248 // rare cases, the error handler itself might deadlock. Here we try to 1249 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1250 // 1251 // This code is in WatcherThread because WatcherThread wakes up 1252 // periodically so the fatal error handler doesn't need to do anything; 1253 // also because the WatcherThread is less likely to crash than other 1254 // threads. 1255 1256 for (;;) { 1257 if (!ShowMessageBoxOnError 1258 && (OnError == NULL || OnError[0] == '\0') 1259 && Arguments::abort_hook() == NULL) { 1260 os::sleep(this, 2 * 60 * 1000, false); 1261 fdStream err(defaultStream::output_fd()); 1262 err.print_raw_cr("# [ timer expired, abort... ]"); 1263 // skip atexit/vm_exit/vm_abort hooks 1264 os::die(); 1265 } 1266 1267 // Wake up 5 seconds later, the fatal handler may reset OnError or 1268 // ShowMessageBoxOnError when it is ready to abort. 1269 os::sleep(this, 5 * 1000, false); 1270 } 1271 } 1272 1273 PeriodicTask::real_time_tick(time_to_wait); 1274 1275 // If we have no more tasks left due to dynamic disenrollment, 1276 // shut down the thread since we don't currently support dynamic enrollment 1277 if (PeriodicTask::num_tasks() == 0) { 1278 _should_terminate = true; 1279 } 1280 } 1281 1282 // Signal that it is terminated 1283 { 1284 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1285 _watcher_thread = NULL; 1286 Terminator_lock->notify(); 1287 } 1288 1289 // Thread destructor usually does this.. 1290 ThreadLocalStorage::set_thread(NULL); 1291} 1292 1293void WatcherThread::start() { 1294 if (watcher_thread() == NULL) { 1295 _should_terminate = false; 1296 // Create the single instance of WatcherThread 1297 new WatcherThread(); 1298 } 1299} 1300 1301void WatcherThread::stop() { 1302 // it is ok to take late safepoints here, if needed 1303 MutexLocker mu(Terminator_lock); 1304 _should_terminate = true; 1305 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1306 1307 Thread* watcher = watcher_thread(); 1308 if (watcher != NULL) 1309 watcher->_SleepEvent->unpark(); 1310 1311 while(watcher_thread() != NULL) { 1312 // This wait should make safepoint checks, wait without a timeout, 1313 // and wait as a suspend-equivalent condition. 1314 // 1315 // Note: If the FlatProfiler is running, then this thread is waiting 1316 // for the WatcherThread to terminate and the WatcherThread, via the 1317 // FlatProfiler task, is waiting for the external suspend request on 1318 // this thread to complete. wait_for_ext_suspend_completion() will 1319 // eventually timeout, but that takes time. Making this wait a 1320 // suspend-equivalent condition solves that timeout problem. 1321 // 1322 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1323 Mutex::_as_suspend_equivalent_flag); 1324 } 1325} 1326 1327void WatcherThread::print_on(outputStream* st) const { 1328 st->print("\"%s\" ", name()); 1329 Thread::print_on(st); 1330 st->cr(); 1331} 1332 1333// ======= JavaThread ======== 1334 1335// A JavaThread is a normal Java thread 1336 1337void JavaThread::initialize() { 1338 // Initialize fields 1339 1340 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1341 set_claimed_par_id(-1); 1342 1343 set_saved_exception_pc(NULL); 1344 set_threadObj(NULL); 1345 _anchor.clear(); 1346 set_entry_point(NULL); 1347 set_jni_functions(jni_functions()); 1348 set_callee_target(NULL); 1349 set_vm_result(NULL); 1350 set_vm_result_2(NULL); 1351 set_vframe_array_head(NULL); 1352 set_vframe_array_last(NULL); 1353 set_deferred_locals(NULL); 1354 set_deopt_mark(NULL); 1355 set_deopt_nmethod(NULL); 1356 clear_must_deopt_id(); 1357 set_monitor_chunks(NULL); 1358 set_next(NULL); 1359 set_thread_state(_thread_new); 1360 set_recorder(NULL); 1361 _terminated = _not_terminated; 1362 _privileged_stack_top = NULL; 1363 _array_for_gc = NULL; 1364 _suspend_equivalent = false; 1365 _in_deopt_handler = 0; 1366 _doing_unsafe_access = false; 1367 _stack_guard_state = stack_guard_unused; 1368 _exception_oop = NULL; 1369 _exception_pc = 0; 1370 _exception_handler_pc = 0; 1371 _is_method_handle_return = 0; 1372 _jvmti_thread_state= NULL; 1373 _should_post_on_exceptions_flag = JNI_FALSE; 1374 _jvmti_get_loaded_classes_closure = NULL; 1375 _interp_only_mode = 0; 1376 _special_runtime_exit_condition = _no_async_condition; 1377 _pending_async_exception = NULL; 1378 _is_compiling = false; 1379 _thread_stat = NULL; 1380 _thread_stat = new ThreadStatistics(); 1381 _blocked_on_compilation = false; 1382 _jni_active_critical = 0; 1383 _do_not_unlock_if_synchronized = false; 1384 _cached_monitor_info = NULL; 1385 _parker = Parker::Allocate(this) ; 1386 1387#ifndef PRODUCT 1388 _jmp_ring_index = 0; 1389 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1390 record_jump(NULL, NULL, NULL, 0); 1391 } 1392#endif /* PRODUCT */ 1393 1394 set_thread_profiler(NULL); 1395 if (FlatProfiler::is_active()) { 1396 // This is where we would decide to either give each thread it's own profiler 1397 // or use one global one from FlatProfiler, 1398 // or up to some count of the number of profiled threads, etc. 1399 ThreadProfiler* pp = new ThreadProfiler(); 1400 pp->engage(); 1401 set_thread_profiler(pp); 1402 } 1403 1404 // Setup safepoint state info for this thread 1405 ThreadSafepointState::create(this); 1406 1407 debug_only(_java_call_counter = 0); 1408 1409 // JVMTI PopFrame support 1410 _popframe_condition = popframe_inactive; 1411 _popframe_preserved_args = NULL; 1412 _popframe_preserved_args_size = 0; 1413 1414 pd_initialize(); 1415} 1416 1417#ifndef SERIALGC 1418SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1419DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1420#endif // !SERIALGC 1421 1422JavaThread::JavaThread(bool is_attaching_via_jni) : 1423 Thread() 1424#ifndef SERIALGC 1425 , _satb_mark_queue(&_satb_mark_queue_set), 1426 _dirty_card_queue(&_dirty_card_queue_set) 1427#endif // !SERIALGC 1428{ 1429 initialize(); 1430 if (is_attaching_via_jni) { 1431 _jni_attach_state = _attaching_via_jni; 1432 } else { 1433 _jni_attach_state = _not_attaching_via_jni; 1434 } 1435 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor"); 1436 _safepoint_visible = false; 1437} 1438 1439bool JavaThread::reguard_stack(address cur_sp) { 1440 if (_stack_guard_state != stack_guard_yellow_disabled) { 1441 return true; // Stack already guarded or guard pages not needed. 1442 } 1443 1444 if (register_stack_overflow()) { 1445 // For those architectures which have separate register and 1446 // memory stacks, we must check the register stack to see if 1447 // it has overflowed. 1448 return false; 1449 } 1450 1451 // Java code never executes within the yellow zone: the latter is only 1452 // there to provoke an exception during stack banging. If java code 1453 // is executing there, either StackShadowPages should be larger, or 1454 // some exception code in c1, c2 or the interpreter isn't unwinding 1455 // when it should. 1456 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1457 1458 enable_stack_yellow_zone(); 1459 return true; 1460} 1461 1462bool JavaThread::reguard_stack(void) { 1463 return reguard_stack(os::current_stack_pointer()); 1464} 1465 1466 1467void JavaThread::block_if_vm_exited() { 1468 if (_terminated == _vm_exited) { 1469 // _vm_exited is set at safepoint, and Threads_lock is never released 1470 // we will block here forever 1471 Threads_lock->lock_without_safepoint_check(); 1472 ShouldNotReachHere(); 1473 } 1474} 1475 1476 1477// Remove this ifdef when C1 is ported to the compiler interface. 1478static void compiler_thread_entry(JavaThread* thread, TRAPS); 1479 1480JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1481 Thread() 1482#ifndef SERIALGC 1483 , _satb_mark_queue(&_satb_mark_queue_set), 1484 _dirty_card_queue(&_dirty_card_queue_set) 1485#endif // !SERIALGC 1486{ 1487 if (TraceThreadEvents) { 1488 tty->print_cr("creating thread %p", this); 1489 } 1490 initialize(); 1491 _jni_attach_state = _not_attaching_via_jni; 1492 set_entry_point(entry_point); 1493 // Create the native thread itself. 1494 // %note runtime_23 1495 os::ThreadType thr_type = os::java_thread; 1496 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1497 os::java_thread; 1498 os::create_thread(this, thr_type, stack_sz); 1499 _safepoint_visible = false; 1500 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1501 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1502 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1503 // the exception consists of creating the exception object & initializing it, initialization 1504 // will leave the VM via a JavaCall and then all locks must be unlocked). 1505 // 1506 // The thread is still suspended when we reach here. Thread must be explicit started 1507 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1508 // by calling Threads:add. The reason why this is not done here, is because the thread 1509 // object must be fully initialized (take a look at JVM_Start) 1510} 1511 1512JavaThread::~JavaThread() { 1513 if (TraceThreadEvents) { 1514 tty->print_cr("terminate thread %p", this); 1515 } 1516 1517 // Info NMT that this JavaThread is exiting, its memory 1518 // recorder should be collected 1519 assert(!is_safepoint_visible(), "wrong state"); 1520 MemTracker::thread_exiting(this); 1521 1522 // JSR166 -- return the parker to the free list 1523 Parker::Release(_parker); 1524 _parker = NULL ; 1525 1526 // Free any remaining previous UnrollBlock 1527 vframeArray* old_array = vframe_array_last(); 1528 1529 if (old_array != NULL) { 1530 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1531 old_array->set_unroll_block(NULL); 1532 delete old_info; 1533 delete old_array; 1534 } 1535 1536 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1537 if (deferred != NULL) { 1538 // This can only happen if thread is destroyed before deoptimization occurs. 1539 assert(deferred->length() != 0, "empty array!"); 1540 do { 1541 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1542 deferred->remove_at(0); 1543 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1544 delete dlv; 1545 } while (deferred->length() != 0); 1546 delete deferred; 1547 } 1548 1549 // All Java related clean up happens in exit 1550 ThreadSafepointState::destroy(this); 1551 if (_thread_profiler != NULL) delete _thread_profiler; 1552 if (_thread_stat != NULL) delete _thread_stat; 1553} 1554 1555 1556// The first routine called by a new Java thread 1557void JavaThread::run() { 1558 // initialize thread-local alloc buffer related fields 1559 this->initialize_tlab(); 1560 1561 // used to test validitity of stack trace backs 1562 this->record_base_of_stack_pointer(); 1563 1564 // Record real stack base and size. 1565 this->record_stack_base_and_size(); 1566 1567 // Initialize thread local storage; set before calling MutexLocker 1568 this->initialize_thread_local_storage(); 1569 1570 this->create_stack_guard_pages(); 1571 1572 this->cache_global_variables(); 1573 1574 // Thread is now sufficient initialized to be handled by the safepoint code as being 1575 // in the VM. Change thread state from _thread_new to _thread_in_vm 1576 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1577 1578 assert(JavaThread::current() == this, "sanity check"); 1579 assert(!Thread::current()->owns_locks(), "sanity check"); 1580 1581 DTRACE_THREAD_PROBE(start, this); 1582 1583 // This operation might block. We call that after all safepoint checks for a new thread has 1584 // been completed. 1585 this->set_active_handles(JNIHandleBlock::allocate_block()); 1586 1587 if (JvmtiExport::should_post_thread_life()) { 1588 JvmtiExport::post_thread_start(this); 1589 } 1590 1591 EVENT_BEGIN(TraceEventThreadStart, event); 1592 EVENT_COMMIT(event, 1593 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj()))); 1594 1595 // We call another function to do the rest so we are sure that the stack addresses used 1596 // from there will be lower than the stack base just computed 1597 thread_main_inner(); 1598 1599 // Note, thread is no longer valid at this point! 1600} 1601 1602 1603void JavaThread::thread_main_inner() { 1604 assert(JavaThread::current() == this, "sanity check"); 1605 assert(this->threadObj() != NULL, "just checking"); 1606 1607 // Execute thread entry point unless this thread has a pending exception 1608 // or has been stopped before starting. 1609 // Note: Due to JVM_StopThread we can have pending exceptions already! 1610 if (!this->has_pending_exception() && 1611 !java_lang_Thread::is_stillborn(this->threadObj())) { 1612 { 1613 ResourceMark rm(this); 1614 this->set_native_thread_name(this->get_thread_name()); 1615 } 1616 HandleMark hm(this); 1617 this->entry_point()(this, this); 1618 } 1619 1620 DTRACE_THREAD_PROBE(stop, this); 1621 1622 this->exit(false); 1623 delete this; 1624} 1625 1626 1627static void ensure_join(JavaThread* thread) { 1628 // We do not need to grap the Threads_lock, since we are operating on ourself. 1629 Handle threadObj(thread, thread->threadObj()); 1630 assert(threadObj.not_null(), "java thread object must exist"); 1631 ObjectLocker lock(threadObj, thread); 1632 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1633 thread->clear_pending_exception(); 1634 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1635 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1636 // Clear the native thread instance - this makes isAlive return false and allows the join() 1637 // to complete once we've done the notify_all below 1638 java_lang_Thread::set_thread(threadObj(), NULL); 1639 lock.notify_all(thread); 1640 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1641 thread->clear_pending_exception(); 1642} 1643 1644 1645// For any new cleanup additions, please check to see if they need to be applied to 1646// cleanup_failed_attach_current_thread as well. 1647void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1648 assert(this == JavaThread::current(), "thread consistency check"); 1649 if (!InitializeJavaLangSystem) return; 1650 1651 HandleMark hm(this); 1652 Handle uncaught_exception(this, this->pending_exception()); 1653 this->clear_pending_exception(); 1654 Handle threadObj(this, this->threadObj()); 1655 assert(threadObj.not_null(), "Java thread object should be created"); 1656 1657 if (get_thread_profiler() != NULL) { 1658 get_thread_profiler()->disengage(); 1659 ResourceMark rm; 1660 get_thread_profiler()->print(get_thread_name()); 1661 } 1662 1663 1664 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1665 { 1666 EXCEPTION_MARK; 1667 1668 CLEAR_PENDING_EXCEPTION; 1669 } 1670 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1671 // has to be fixed by a runtime query method 1672 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1673 // JSR-166: change call from from ThreadGroup.uncaughtException to 1674 // java.lang.Thread.dispatchUncaughtException 1675 if (uncaught_exception.not_null()) { 1676 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1677 { 1678 EXCEPTION_MARK; 1679 // Check if the method Thread.dispatchUncaughtException() exists. If so 1680 // call it. Otherwise we have an older library without the JSR-166 changes, 1681 // so call ThreadGroup.uncaughtException() 1682 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1683 CallInfo callinfo; 1684 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1685 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1686 vmSymbols::dispatchUncaughtException_name(), 1687 vmSymbols::throwable_void_signature(), 1688 KlassHandle(), false, false, THREAD); 1689 CLEAR_PENDING_EXCEPTION; 1690 methodHandle method = callinfo.selected_method(); 1691 if (method.not_null()) { 1692 JavaValue result(T_VOID); 1693 JavaCalls::call_virtual(&result, 1694 threadObj, thread_klass, 1695 vmSymbols::dispatchUncaughtException_name(), 1696 vmSymbols::throwable_void_signature(), 1697 uncaught_exception, 1698 THREAD); 1699 } else { 1700 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1701 JavaValue result(T_VOID); 1702 JavaCalls::call_virtual(&result, 1703 group, thread_group, 1704 vmSymbols::uncaughtException_name(), 1705 vmSymbols::thread_throwable_void_signature(), 1706 threadObj, // Arg 1 1707 uncaught_exception, // Arg 2 1708 THREAD); 1709 } 1710 if (HAS_PENDING_EXCEPTION) { 1711 ResourceMark rm(this); 1712 jio_fprintf(defaultStream::error_stream(), 1713 "\nException: %s thrown from the UncaughtExceptionHandler" 1714 " in thread \"%s\"\n", 1715 Klass::cast(pending_exception()->klass())->external_name(), 1716 get_thread_name()); 1717 CLEAR_PENDING_EXCEPTION; 1718 } 1719 } 1720 } 1721 1722 // Called before the java thread exit since we want to read info 1723 // from java_lang_Thread object 1724 EVENT_BEGIN(TraceEventThreadEnd, event); 1725 EVENT_COMMIT(event, 1726 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj()))); 1727 1728 // Call after last event on thread 1729 EVENT_THREAD_EXIT(this); 1730 1731 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1732 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1733 // is deprecated anyhow. 1734 { int count = 3; 1735 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1736 EXCEPTION_MARK; 1737 JavaValue result(T_VOID); 1738 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1739 JavaCalls::call_virtual(&result, 1740 threadObj, thread_klass, 1741 vmSymbols::exit_method_name(), 1742 vmSymbols::void_method_signature(), 1743 THREAD); 1744 CLEAR_PENDING_EXCEPTION; 1745 } 1746 } 1747 1748 // notify JVMTI 1749 if (JvmtiExport::should_post_thread_life()) { 1750 JvmtiExport::post_thread_end(this); 1751 } 1752 1753 // We have notified the agents that we are exiting, before we go on, 1754 // we must check for a pending external suspend request and honor it 1755 // in order to not surprise the thread that made the suspend request. 1756 while (true) { 1757 { 1758 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1759 if (!is_external_suspend()) { 1760 set_terminated(_thread_exiting); 1761 ThreadService::current_thread_exiting(this); 1762 break; 1763 } 1764 // Implied else: 1765 // Things get a little tricky here. We have a pending external 1766 // suspend request, but we are holding the SR_lock so we 1767 // can't just self-suspend. So we temporarily drop the lock 1768 // and then self-suspend. 1769 } 1770 1771 ThreadBlockInVM tbivm(this); 1772 java_suspend_self(); 1773 1774 // We're done with this suspend request, but we have to loop around 1775 // and check again. Eventually we will get SR_lock without a pending 1776 // external suspend request and will be able to mark ourselves as 1777 // exiting. 1778 } 1779 // no more external suspends are allowed at this point 1780 } else { 1781 // before_exit() has already posted JVMTI THREAD_END events 1782 } 1783 1784 // Notify waiters on thread object. This has to be done after exit() is called 1785 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1786 // group should have the destroyed bit set before waiters are notified). 1787 ensure_join(this); 1788 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1789 1790 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1791 // held by this thread must be released. A detach operation must only 1792 // get here if there are no Java frames on the stack. Therefore, any 1793 // owned monitors at this point MUST be JNI-acquired monitors which are 1794 // pre-inflated and in the monitor cache. 1795 // 1796 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1797 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1798 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1799 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1800 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1801 } 1802 1803 // These things needs to be done while we are still a Java Thread. Make sure that thread 1804 // is in a consistent state, in case GC happens 1805 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1806 1807 if (active_handles() != NULL) { 1808 JNIHandleBlock* block = active_handles(); 1809 set_active_handles(NULL); 1810 JNIHandleBlock::release_block(block); 1811 } 1812 1813 if (free_handle_block() != NULL) { 1814 JNIHandleBlock* block = free_handle_block(); 1815 set_free_handle_block(NULL); 1816 JNIHandleBlock::release_block(block); 1817 } 1818 1819 // These have to be removed while this is still a valid thread. 1820 remove_stack_guard_pages(); 1821 1822 if (UseTLAB) { 1823 tlab().make_parsable(true); // retire TLAB 1824 } 1825 1826 if (JvmtiEnv::environments_might_exist()) { 1827 JvmtiExport::cleanup_thread(this); 1828 } 1829 1830#ifndef SERIALGC 1831 // We must flush G1-related buffers before removing a thread from 1832 // the list of active threads. 1833 if (UseG1GC) { 1834 flush_barrier_queues(); 1835 } 1836#endif 1837 1838 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1839 Threads::remove(this); 1840} 1841 1842#ifndef SERIALGC 1843// Flush G1-related queues. 1844void JavaThread::flush_barrier_queues() { 1845 satb_mark_queue().flush(); 1846 dirty_card_queue().flush(); 1847} 1848 1849void JavaThread::initialize_queues() { 1850 assert(!SafepointSynchronize::is_at_safepoint(), 1851 "we should not be at a safepoint"); 1852 1853 ObjPtrQueue& satb_queue = satb_mark_queue(); 1854 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1855 // The SATB queue should have been constructed with its active 1856 // field set to false. 1857 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1858 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1859 // If we are creating the thread during a marking cycle, we should 1860 // set the active field of the SATB queue to true. 1861 if (satb_queue_set.is_active()) { 1862 satb_queue.set_active(true); 1863 } 1864 1865 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1866 // The dirty card queue should have been constructed with its 1867 // active field set to true. 1868 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1869} 1870#endif // !SERIALGC 1871 1872void JavaThread::cleanup_failed_attach_current_thread() { 1873 if (get_thread_profiler() != NULL) { 1874 get_thread_profiler()->disengage(); 1875 ResourceMark rm; 1876 get_thread_profiler()->print(get_thread_name()); 1877 } 1878 1879 if (active_handles() != NULL) { 1880 JNIHandleBlock* block = active_handles(); 1881 set_active_handles(NULL); 1882 JNIHandleBlock::release_block(block); 1883 } 1884 1885 if (free_handle_block() != NULL) { 1886 JNIHandleBlock* block = free_handle_block(); 1887 set_free_handle_block(NULL); 1888 JNIHandleBlock::release_block(block); 1889 } 1890 1891 // These have to be removed while this is still a valid thread. 1892 remove_stack_guard_pages(); 1893 1894 if (UseTLAB) { 1895 tlab().make_parsable(true); // retire TLAB, if any 1896 } 1897 1898#ifndef SERIALGC 1899 if (UseG1GC) { 1900 flush_barrier_queues(); 1901 } 1902#endif 1903 1904 Threads::remove(this); 1905 delete this; 1906} 1907 1908 1909 1910 1911JavaThread* JavaThread::active() { 1912 Thread* thread = ThreadLocalStorage::thread(); 1913 assert(thread != NULL, "just checking"); 1914 if (thread->is_Java_thread()) { 1915 return (JavaThread*) thread; 1916 } else { 1917 assert(thread->is_VM_thread(), "this must be a vm thread"); 1918 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1919 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1920 assert(ret->is_Java_thread(), "must be a Java thread"); 1921 return ret; 1922 } 1923} 1924 1925bool JavaThread::is_lock_owned(address adr) const { 1926 if (Thread::is_lock_owned(adr)) return true; 1927 1928 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1929 if (chunk->contains(adr)) return true; 1930 } 1931 1932 return false; 1933} 1934 1935 1936void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1937 chunk->set_next(monitor_chunks()); 1938 set_monitor_chunks(chunk); 1939} 1940 1941void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1942 guarantee(monitor_chunks() != NULL, "must be non empty"); 1943 if (monitor_chunks() == chunk) { 1944 set_monitor_chunks(chunk->next()); 1945 } else { 1946 MonitorChunk* prev = monitor_chunks(); 1947 while (prev->next() != chunk) prev = prev->next(); 1948 prev->set_next(chunk->next()); 1949 } 1950} 1951 1952// JVM support. 1953 1954// Note: this function shouldn't block if it's called in 1955// _thread_in_native_trans state (such as from 1956// check_special_condition_for_native_trans()). 1957void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 1958 1959 if (has_last_Java_frame() && has_async_condition()) { 1960 // If we are at a polling page safepoint (not a poll return) 1961 // then we must defer async exception because live registers 1962 // will be clobbered by the exception path. Poll return is 1963 // ok because the call we a returning from already collides 1964 // with exception handling registers and so there is no issue. 1965 // (The exception handling path kills call result registers but 1966 // this is ok since the exception kills the result anyway). 1967 1968 if (is_at_poll_safepoint()) { 1969 // if the code we are returning to has deoptimized we must defer 1970 // the exception otherwise live registers get clobbered on the 1971 // exception path before deoptimization is able to retrieve them. 1972 // 1973 RegisterMap map(this, false); 1974 frame caller_fr = last_frame().sender(&map); 1975 assert(caller_fr.is_compiled_frame(), "what?"); 1976 if (caller_fr.is_deoptimized_frame()) { 1977 if (TraceExceptions) { 1978 ResourceMark rm; 1979 tty->print_cr("deferred async exception at compiled safepoint"); 1980 } 1981 return; 1982 } 1983 } 1984 } 1985 1986 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 1987 if (condition == _no_async_condition) { 1988 // Conditions have changed since has_special_runtime_exit_condition() 1989 // was called: 1990 // - if we were here only because of an external suspend request, 1991 // then that was taken care of above (or cancelled) so we are done 1992 // - if we were here because of another async request, then it has 1993 // been cleared between the has_special_runtime_exit_condition() 1994 // and now so again we are done 1995 return; 1996 } 1997 1998 // Check for pending async. exception 1999 if (_pending_async_exception != NULL) { 2000 // Only overwrite an already pending exception, if it is not a threadDeath. 2001 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2002 2003 // We cannot call Exceptions::_throw(...) here because we cannot block 2004 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2005 2006 if (TraceExceptions) { 2007 ResourceMark rm; 2008 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2009 if (has_last_Java_frame() ) { 2010 frame f = last_frame(); 2011 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2012 } 2013 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2014 } 2015 _pending_async_exception = NULL; 2016 clear_has_async_exception(); 2017 } 2018 } 2019 2020 if (check_unsafe_error && 2021 condition == _async_unsafe_access_error && !has_pending_exception()) { 2022 condition = _no_async_condition; // done 2023 switch (thread_state()) { 2024 case _thread_in_vm: 2025 { 2026 JavaThread* THREAD = this; 2027 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2028 } 2029 case _thread_in_native: 2030 { 2031 ThreadInVMfromNative tiv(this); 2032 JavaThread* THREAD = this; 2033 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2034 } 2035 case _thread_in_Java: 2036 { 2037 ThreadInVMfromJava tiv(this); 2038 JavaThread* THREAD = this; 2039 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2040 } 2041 default: 2042 ShouldNotReachHere(); 2043 } 2044 } 2045 2046 assert(condition == _no_async_condition || has_pending_exception() || 2047 (!check_unsafe_error && condition == _async_unsafe_access_error), 2048 "must have handled the async condition, if no exception"); 2049} 2050 2051void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2052 // 2053 // Check for pending external suspend. Internal suspend requests do 2054 // not use handle_special_runtime_exit_condition(). 2055 // If JNIEnv proxies are allowed, don't self-suspend if the target 2056 // thread is not the current thread. In older versions of jdbx, jdbx 2057 // threads could call into the VM with another thread's JNIEnv so we 2058 // can be here operating on behalf of a suspended thread (4432884). 2059 bool do_self_suspend = is_external_suspend_with_lock(); 2060 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2061 // 2062 // Because thread is external suspended the safepoint code will count 2063 // thread as at a safepoint. This can be odd because we can be here 2064 // as _thread_in_Java which would normally transition to _thread_blocked 2065 // at a safepoint. We would like to mark the thread as _thread_blocked 2066 // before calling java_suspend_self like all other callers of it but 2067 // we must then observe proper safepoint protocol. (We can't leave 2068 // _thread_blocked with a safepoint in progress). However we can be 2069 // here as _thread_in_native_trans so we can't use a normal transition 2070 // constructor/destructor pair because they assert on that type of 2071 // transition. We could do something like: 2072 // 2073 // JavaThreadState state = thread_state(); 2074 // set_thread_state(_thread_in_vm); 2075 // { 2076 // ThreadBlockInVM tbivm(this); 2077 // java_suspend_self() 2078 // } 2079 // set_thread_state(_thread_in_vm_trans); 2080 // if (safepoint) block; 2081 // set_thread_state(state); 2082 // 2083 // but that is pretty messy. Instead we just go with the way the 2084 // code has worked before and note that this is the only path to 2085 // java_suspend_self that doesn't put the thread in _thread_blocked 2086 // mode. 2087 2088 frame_anchor()->make_walkable(this); 2089 java_suspend_self(); 2090 2091 // We might be here for reasons in addition to the self-suspend request 2092 // so check for other async requests. 2093 } 2094 2095 if (check_asyncs) { 2096 check_and_handle_async_exceptions(); 2097 } 2098} 2099 2100void JavaThread::send_thread_stop(oop java_throwable) { 2101 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2102 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2103 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2104 2105 // Do not throw asynchronous exceptions against the compiler thread 2106 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2107 if (is_Compiler_thread()) return; 2108 2109 { 2110 // Actually throw the Throwable against the target Thread - however 2111 // only if there is no thread death exception installed already. 2112 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2113 // If the topmost frame is a runtime stub, then we are calling into 2114 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2115 // must deoptimize the caller before continuing, as the compiled exception handler table 2116 // may not be valid 2117 if (has_last_Java_frame()) { 2118 frame f = last_frame(); 2119 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2120 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2121 RegisterMap reg_map(this, UseBiasedLocking); 2122 frame compiled_frame = f.sender(®_map); 2123 if (compiled_frame.can_be_deoptimized()) { 2124 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2125 } 2126 } 2127 } 2128 2129 // Set async. pending exception in thread. 2130 set_pending_async_exception(java_throwable); 2131 2132 if (TraceExceptions) { 2133 ResourceMark rm; 2134 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2135 } 2136 // for AbortVMOnException flag 2137 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2138 } 2139 } 2140 2141 2142 // Interrupt thread so it will wake up from a potential wait() 2143 Thread::interrupt(this); 2144} 2145 2146// External suspension mechanism. 2147// 2148// Tell the VM to suspend a thread when ever it knows that it does not hold on 2149// to any VM_locks and it is at a transition 2150// Self-suspension will happen on the transition out of the vm. 2151// Catch "this" coming in from JNIEnv pointers when the thread has been freed 2152// 2153// Guarantees on return: 2154// + Target thread will not execute any new bytecode (that's why we need to 2155// force a safepoint) 2156// + Target thread will not enter any new monitors 2157// 2158void JavaThread::java_suspend() { 2159 { MutexLocker mu(Threads_lock); 2160 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2161 return; 2162 } 2163 } 2164 2165 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2166 if (!is_external_suspend()) { 2167 // a racing resume has cancelled us; bail out now 2168 return; 2169 } 2170 2171 // suspend is done 2172 uint32_t debug_bits = 0; 2173 // Warning: is_ext_suspend_completed() may temporarily drop the 2174 // SR_lock to allow the thread to reach a stable thread state if 2175 // it is currently in a transient thread state. 2176 if (is_ext_suspend_completed(false /* !called_by_wait */, 2177 SuspendRetryDelay, &debug_bits) ) { 2178 return; 2179 } 2180 } 2181 2182 VM_ForceSafepoint vm_suspend; 2183 VMThread::execute(&vm_suspend); 2184} 2185 2186// Part II of external suspension. 2187// A JavaThread self suspends when it detects a pending external suspend 2188// request. This is usually on transitions. It is also done in places 2189// where continuing to the next transition would surprise the caller, 2190// e.g., monitor entry. 2191// 2192// Returns the number of times that the thread self-suspended. 2193// 2194// Note: DO NOT call java_suspend_self() when you just want to block current 2195// thread. java_suspend_self() is the second stage of cooperative 2196// suspension for external suspend requests and should only be used 2197// to complete an external suspend request. 2198// 2199int JavaThread::java_suspend_self() { 2200 int ret = 0; 2201 2202 // we are in the process of exiting so don't suspend 2203 if (is_exiting()) { 2204 clear_external_suspend(); 2205 return ret; 2206 } 2207 2208 assert(_anchor.walkable() || 2209 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2210 "must have walkable stack"); 2211 2212 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2213 2214 assert(!this->is_ext_suspended(), 2215 "a thread trying to self-suspend should not already be suspended"); 2216 2217 if (this->is_suspend_equivalent()) { 2218 // If we are self-suspending as a result of the lifting of a 2219 // suspend equivalent condition, then the suspend_equivalent 2220 // flag is not cleared until we set the ext_suspended flag so 2221 // that wait_for_ext_suspend_completion() returns consistent 2222 // results. 2223 this->clear_suspend_equivalent(); 2224 } 2225 2226 // A racing resume may have cancelled us before we grabbed SR_lock 2227 // above. Or another external suspend request could be waiting for us 2228 // by the time we return from SR_lock()->wait(). The thread 2229 // that requested the suspension may already be trying to walk our 2230 // stack and if we return now, we can change the stack out from under 2231 // it. This would be a "bad thing (TM)" and cause the stack walker 2232 // to crash. We stay self-suspended until there are no more pending 2233 // external suspend requests. 2234 while (is_external_suspend()) { 2235 ret++; 2236 this->set_ext_suspended(); 2237 2238 // _ext_suspended flag is cleared by java_resume() 2239 while (is_ext_suspended()) { 2240 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2241 } 2242 } 2243 2244 return ret; 2245} 2246 2247#ifdef ASSERT 2248// verify the JavaThread has not yet been published in the Threads::list, and 2249// hence doesn't need protection from concurrent access at this stage 2250void JavaThread::verify_not_published() { 2251 if (!Threads_lock->owned_by_self()) { 2252 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2253 assert( !Threads::includes(this), 2254 "java thread shouldn't have been published yet!"); 2255 } 2256 else { 2257 assert( !Threads::includes(this), 2258 "java thread shouldn't have been published yet!"); 2259 } 2260} 2261#endif 2262 2263// Slow path when the native==>VM/Java barriers detect a safepoint is in 2264// progress or when _suspend_flags is non-zero. 2265// Current thread needs to self-suspend if there is a suspend request and/or 2266// block if a safepoint is in progress. 2267// Async exception ISN'T checked. 2268// Note only the ThreadInVMfromNative transition can call this function 2269// directly and when thread state is _thread_in_native_trans 2270void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2271 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2272 2273 JavaThread *curJT = JavaThread::current(); 2274 bool do_self_suspend = thread->is_external_suspend(); 2275 2276 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2277 2278 // If JNIEnv proxies are allowed, don't self-suspend if the target 2279 // thread is not the current thread. In older versions of jdbx, jdbx 2280 // threads could call into the VM with another thread's JNIEnv so we 2281 // can be here operating on behalf of a suspended thread (4432884). 2282 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2283 JavaThreadState state = thread->thread_state(); 2284 2285 // We mark this thread_blocked state as a suspend-equivalent so 2286 // that a caller to is_ext_suspend_completed() won't be confused. 2287 // The suspend-equivalent state is cleared by java_suspend_self(). 2288 thread->set_suspend_equivalent(); 2289 2290 // If the safepoint code sees the _thread_in_native_trans state, it will 2291 // wait until the thread changes to other thread state. There is no 2292 // guarantee on how soon we can obtain the SR_lock and complete the 2293 // self-suspend request. It would be a bad idea to let safepoint wait for 2294 // too long. Temporarily change the state to _thread_blocked to 2295 // let the VM thread know that this thread is ready for GC. The problem 2296 // of changing thread state is that safepoint could happen just after 2297 // java_suspend_self() returns after being resumed, and VM thread will 2298 // see the _thread_blocked state. We must check for safepoint 2299 // after restoring the state and make sure we won't leave while a safepoint 2300 // is in progress. 2301 thread->set_thread_state(_thread_blocked); 2302 thread->java_suspend_self(); 2303 thread->set_thread_state(state); 2304 // Make sure new state is seen by VM thread 2305 if (os::is_MP()) { 2306 if (UseMembar) { 2307 // Force a fence between the write above and read below 2308 OrderAccess::fence(); 2309 } else { 2310 // Must use this rather than serialization page in particular on Windows 2311 InterfaceSupport::serialize_memory(thread); 2312 } 2313 } 2314 } 2315 2316 if (SafepointSynchronize::do_call_back()) { 2317 // If we are safepointing, then block the caller which may not be 2318 // the same as the target thread (see above). 2319 SafepointSynchronize::block(curJT); 2320 } 2321 2322 if (thread->is_deopt_suspend()) { 2323 thread->clear_deopt_suspend(); 2324 RegisterMap map(thread, false); 2325 frame f = thread->last_frame(); 2326 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2327 f = f.sender(&map); 2328 } 2329 if (f.id() == thread->must_deopt_id()) { 2330 thread->clear_must_deopt_id(); 2331 f.deoptimize(thread); 2332 } else { 2333 fatal("missed deoptimization!"); 2334 } 2335 } 2336} 2337 2338// Slow path when the native==>VM/Java barriers detect a safepoint is in 2339// progress or when _suspend_flags is non-zero. 2340// Current thread needs to self-suspend if there is a suspend request and/or 2341// block if a safepoint is in progress. 2342// Also check for pending async exception (not including unsafe access error). 2343// Note only the native==>VM/Java barriers can call this function and when 2344// thread state is _thread_in_native_trans. 2345void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2346 check_safepoint_and_suspend_for_native_trans(thread); 2347 2348 if (thread->has_async_exception()) { 2349 // We are in _thread_in_native_trans state, don't handle unsafe 2350 // access error since that may block. 2351 thread->check_and_handle_async_exceptions(false); 2352 } 2353} 2354 2355// This is a variant of the normal 2356// check_special_condition_for_native_trans with slightly different 2357// semantics for use by critical native wrappers. It does all the 2358// normal checks but also performs the transition back into 2359// thread_in_Java state. This is required so that critical natives 2360// can potentially block and perform a GC if they are the last thread 2361// exiting the GC_locker. 2362void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2363 check_special_condition_for_native_trans(thread); 2364 2365 // Finish the transition 2366 thread->set_thread_state(_thread_in_Java); 2367 2368 if (thread->do_critical_native_unlock()) { 2369 ThreadInVMfromJavaNoAsyncException tiv(thread); 2370 GC_locker::unlock_critical(thread); 2371 thread->clear_critical_native_unlock(); 2372 } 2373} 2374 2375// We need to guarantee the Threads_lock here, since resumes are not 2376// allowed during safepoint synchronization 2377// Can only resume from an external suspension 2378void JavaThread::java_resume() { 2379 assert_locked_or_safepoint(Threads_lock); 2380 2381 // Sanity check: thread is gone, has started exiting or the thread 2382 // was not externally suspended. 2383 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2384 return; 2385 } 2386 2387 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2388 2389 clear_external_suspend(); 2390 2391 if (is_ext_suspended()) { 2392 clear_ext_suspended(); 2393 SR_lock()->notify_all(); 2394 } 2395} 2396 2397void JavaThread::create_stack_guard_pages() { 2398 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2399 address low_addr = stack_base() - stack_size(); 2400 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2401 2402 int allocate = os::allocate_stack_guard_pages(); 2403 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2404 2405 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2406 warning("Attempt to allocate stack guard pages failed."); 2407 return; 2408 } 2409 2410 if (os::guard_memory((char *) low_addr, len)) { 2411 _stack_guard_state = stack_guard_enabled; 2412 } else { 2413 warning("Attempt to protect stack guard pages failed."); 2414 if (os::uncommit_memory((char *) low_addr, len)) { 2415 warning("Attempt to deallocate stack guard pages failed."); 2416 } 2417 } 2418} 2419 2420void JavaThread::remove_stack_guard_pages() { 2421 if (_stack_guard_state == stack_guard_unused) return; 2422 address low_addr = stack_base() - stack_size(); 2423 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2424 2425 if (os::allocate_stack_guard_pages()) { 2426 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2427 _stack_guard_state = stack_guard_unused; 2428 } else { 2429 warning("Attempt to deallocate stack guard pages failed."); 2430 } 2431 } else { 2432 if (_stack_guard_state == stack_guard_unused) return; 2433 if (os::unguard_memory((char *) low_addr, len)) { 2434 _stack_guard_state = stack_guard_unused; 2435 } else { 2436 warning("Attempt to unprotect stack guard pages failed."); 2437 } 2438 } 2439} 2440 2441void JavaThread::enable_stack_yellow_zone() { 2442 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2443 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2444 2445 // The base notation is from the stacks point of view, growing downward. 2446 // We need to adjust it to work correctly with guard_memory() 2447 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2448 2449 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2450 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2451 2452 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2453 _stack_guard_state = stack_guard_enabled; 2454 } else { 2455 warning("Attempt to guard stack yellow zone failed."); 2456 } 2457 enable_register_stack_guard(); 2458} 2459 2460void JavaThread::disable_stack_yellow_zone() { 2461 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2462 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2463 2464 // Simply return if called for a thread that does not use guard pages. 2465 if (_stack_guard_state == stack_guard_unused) return; 2466 2467 // The base notation is from the stacks point of view, growing downward. 2468 // We need to adjust it to work correctly with guard_memory() 2469 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2470 2471 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2472 _stack_guard_state = stack_guard_yellow_disabled; 2473 } else { 2474 warning("Attempt to unguard stack yellow zone failed."); 2475 } 2476 disable_register_stack_guard(); 2477} 2478 2479void JavaThread::enable_stack_red_zone() { 2480 // The base notation is from the stacks point of view, growing downward. 2481 // We need to adjust it to work correctly with guard_memory() 2482 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2483 address base = stack_red_zone_base() - stack_red_zone_size(); 2484 2485 guarantee(base < stack_base(),"Error calculating stack red zone"); 2486 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2487 2488 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2489 warning("Attempt to guard stack red zone failed."); 2490 } 2491} 2492 2493void JavaThread::disable_stack_red_zone() { 2494 // The base notation is from the stacks point of view, growing downward. 2495 // We need to adjust it to work correctly with guard_memory() 2496 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2497 address base = stack_red_zone_base() - stack_red_zone_size(); 2498 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2499 warning("Attempt to unguard stack red zone failed."); 2500 } 2501} 2502 2503void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2504 // ignore is there is no stack 2505 if (!has_last_Java_frame()) return; 2506 // traverse the stack frames. Starts from top frame. 2507 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2508 frame* fr = fst.current(); 2509 f(fr, fst.register_map()); 2510 } 2511} 2512 2513 2514#ifndef PRODUCT 2515// Deoptimization 2516// Function for testing deoptimization 2517void JavaThread::deoptimize() { 2518 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2519 StackFrameStream fst(this, UseBiasedLocking); 2520 bool deopt = false; // Dump stack only if a deopt actually happens. 2521 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2522 // Iterate over all frames in the thread and deoptimize 2523 for(; !fst.is_done(); fst.next()) { 2524 if(fst.current()->can_be_deoptimized()) { 2525 2526 if (only_at) { 2527 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2528 // consists of comma or carriage return separated numbers so 2529 // search for the current bci in that string. 2530 address pc = fst.current()->pc(); 2531 nmethod* nm = (nmethod*) fst.current()->cb(); 2532 ScopeDesc* sd = nm->scope_desc_at( pc); 2533 char buffer[8]; 2534 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2535 size_t len = strlen(buffer); 2536 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2537 while (found != NULL) { 2538 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2539 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2540 // Check that the bci found is bracketed by terminators. 2541 break; 2542 } 2543 found = strstr(found + 1, buffer); 2544 } 2545 if (!found) { 2546 continue; 2547 } 2548 } 2549 2550 if (DebugDeoptimization && !deopt) { 2551 deopt = true; // One-time only print before deopt 2552 tty->print_cr("[BEFORE Deoptimization]"); 2553 trace_frames(); 2554 trace_stack(); 2555 } 2556 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2557 } 2558 } 2559 2560 if (DebugDeoptimization && deopt) { 2561 tty->print_cr("[AFTER Deoptimization]"); 2562 trace_frames(); 2563 } 2564} 2565 2566 2567// Make zombies 2568void JavaThread::make_zombies() { 2569 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2570 if (fst.current()->can_be_deoptimized()) { 2571 // it is a Java nmethod 2572 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2573 nm->make_not_entrant(); 2574 } 2575 } 2576} 2577#endif // PRODUCT 2578 2579 2580void JavaThread::deoptimized_wrt_marked_nmethods() { 2581 if (!has_last_Java_frame()) return; 2582 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2583 StackFrameStream fst(this, UseBiasedLocking); 2584 for(; !fst.is_done(); fst.next()) { 2585 if (fst.current()->should_be_deoptimized()) { 2586 if (LogCompilation && xtty != NULL) { 2587 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2588 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2589 this->name(), nm != NULL ? nm->compile_id() : -1); 2590 } 2591 2592 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2593 } 2594 } 2595} 2596 2597 2598// GC support 2599static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2600 2601void JavaThread::gc_epilogue() { 2602 frames_do(frame_gc_epilogue); 2603} 2604 2605 2606static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2607 2608void JavaThread::gc_prologue() { 2609 frames_do(frame_gc_prologue); 2610} 2611 2612// If the caller is a NamedThread, then remember, in the current scope, 2613// the given JavaThread in its _processed_thread field. 2614class RememberProcessedThread: public StackObj { 2615 NamedThread* _cur_thr; 2616public: 2617 RememberProcessedThread(JavaThread* jthr) { 2618 Thread* thread = Thread::current(); 2619 if (thread->is_Named_thread()) { 2620 _cur_thr = (NamedThread *)thread; 2621 _cur_thr->set_processed_thread(jthr); 2622 } else { 2623 _cur_thr = NULL; 2624 } 2625 } 2626 2627 ~RememberProcessedThread() { 2628 if (_cur_thr) { 2629 _cur_thr->set_processed_thread(NULL); 2630 } 2631 } 2632}; 2633 2634void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 2635 // Verify that the deferred card marks have been flushed. 2636 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2637 2638 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2639 // since there may be more than one thread using each ThreadProfiler. 2640 2641 // Traverse the GCHandles 2642 Thread::oops_do(f, cf); 2643 2644 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2645 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2646 2647 if (has_last_Java_frame()) { 2648 // Record JavaThread to GC thread 2649 RememberProcessedThread rpt(this); 2650 2651 // Traverse the privileged stack 2652 if (_privileged_stack_top != NULL) { 2653 _privileged_stack_top->oops_do(f); 2654 } 2655 2656 // traverse the registered growable array 2657 if (_array_for_gc != NULL) { 2658 for (int index = 0; index < _array_for_gc->length(); index++) { 2659 f->do_oop(_array_for_gc->adr_at(index)); 2660 } 2661 } 2662 2663 // Traverse the monitor chunks 2664 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2665 chunk->oops_do(f); 2666 } 2667 2668 // Traverse the execution stack 2669 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2670 fst.current()->oops_do(f, cf, fst.register_map()); 2671 } 2672 } 2673 2674 // callee_target is never live across a gc point so NULL it here should 2675 // it still contain a methdOop. 2676 2677 set_callee_target(NULL); 2678 2679 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2680 // If we have deferred set_locals there might be oops waiting to be 2681 // written 2682 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2683 if (list != NULL) { 2684 for (int i = 0; i < list->length(); i++) { 2685 list->at(i)->oops_do(f); 2686 } 2687 } 2688 2689 // Traverse instance variables at the end since the GC may be moving things 2690 // around using this function 2691 f->do_oop((oop*) &_threadObj); 2692 f->do_oop((oop*) &_vm_result); 2693 f->do_oop((oop*) &_exception_oop); 2694 f->do_oop((oop*) &_pending_async_exception); 2695 2696 if (jvmti_thread_state() != NULL) { 2697 jvmti_thread_state()->oops_do(f); 2698 } 2699} 2700 2701void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2702 Thread::nmethods_do(cf); // (super method is a no-op) 2703 2704 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2705 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2706 2707 if (has_last_Java_frame()) { 2708 // Traverse the execution stack 2709 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2710 fst.current()->nmethods_do(cf); 2711 } 2712 } 2713} 2714 2715void JavaThread::metadata_do(void f(Metadata*)) { 2716 Thread::metadata_do(f); 2717 if (has_last_Java_frame()) { 2718 // Traverse the execution stack to call f() on the methods in the stack 2719 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2720 fst.current()->metadata_do(f); 2721 } 2722 } else if (is_Compiler_thread()) { 2723 // need to walk ciMetadata in current compile tasks to keep alive. 2724 CompilerThread* ct = (CompilerThread*)this; 2725 if (ct->env() != NULL) { 2726 ct->env()->metadata_do(f); 2727 } 2728 } 2729} 2730 2731// Printing 2732const char* _get_thread_state_name(JavaThreadState _thread_state) { 2733 switch (_thread_state) { 2734 case _thread_uninitialized: return "_thread_uninitialized"; 2735 case _thread_new: return "_thread_new"; 2736 case _thread_new_trans: return "_thread_new_trans"; 2737 case _thread_in_native: return "_thread_in_native"; 2738 case _thread_in_native_trans: return "_thread_in_native_trans"; 2739 case _thread_in_vm: return "_thread_in_vm"; 2740 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2741 case _thread_in_Java: return "_thread_in_Java"; 2742 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2743 case _thread_blocked: return "_thread_blocked"; 2744 case _thread_blocked_trans: return "_thread_blocked_trans"; 2745 default: return "unknown thread state"; 2746 } 2747} 2748 2749#ifndef PRODUCT 2750void JavaThread::print_thread_state_on(outputStream *st) const { 2751 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2752}; 2753void JavaThread::print_thread_state() const { 2754 print_thread_state_on(tty); 2755}; 2756#endif // PRODUCT 2757 2758// Called by Threads::print() for VM_PrintThreads operation 2759void JavaThread::print_on(outputStream *st) const { 2760 st->print("\"%s\" ", get_thread_name()); 2761 oop thread_oop = threadObj(); 2762 if (thread_oop != NULL) { 2763 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2764 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2765 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2766 } 2767 Thread::print_on(st); 2768 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2769 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2770 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2771 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2772 } 2773#ifndef PRODUCT 2774 print_thread_state_on(st); 2775 _safepoint_state->print_on(st); 2776#endif // PRODUCT 2777} 2778 2779// Called by fatal error handler. The difference between this and 2780// JavaThread::print() is that we can't grab lock or allocate memory. 2781void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2782 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2783 oop thread_obj = threadObj(); 2784 if (thread_obj != NULL) { 2785 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2786 } 2787 st->print(" ["); 2788 st->print("%s", _get_thread_state_name(_thread_state)); 2789 if (osthread()) { 2790 st->print(", id=%d", osthread()->thread_id()); 2791 } 2792 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2793 _stack_base - _stack_size, _stack_base); 2794 st->print("]"); 2795 return; 2796} 2797 2798// Verification 2799 2800static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2801 2802void JavaThread::verify() { 2803 // Verify oops in the thread. 2804 oops_do(&VerifyOopClosure::verify_oop, NULL); 2805 2806 // Verify the stack frames. 2807 frames_do(frame_verify); 2808} 2809 2810// CR 6300358 (sub-CR 2137150) 2811// Most callers of this method assume that it can't return NULL but a 2812// thread may not have a name whilst it is in the process of attaching to 2813// the VM - see CR 6412693, and there are places where a JavaThread can be 2814// seen prior to having it's threadObj set (eg JNI attaching threads and 2815// if vm exit occurs during initialization). These cases can all be accounted 2816// for such that this method never returns NULL. 2817const char* JavaThread::get_thread_name() const { 2818#ifdef ASSERT 2819 // early safepoints can hit while current thread does not yet have TLS 2820 if (!SafepointSynchronize::is_at_safepoint()) { 2821 Thread *cur = Thread::current(); 2822 if (!(cur->is_Java_thread() && cur == this)) { 2823 // Current JavaThreads are allowed to get their own name without 2824 // the Threads_lock. 2825 assert_locked_or_safepoint(Threads_lock); 2826 } 2827 } 2828#endif // ASSERT 2829 return get_thread_name_string(); 2830} 2831 2832// Returns a non-NULL representation of this thread's name, or a suitable 2833// descriptive string if there is no set name 2834const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2835 const char* name_str; 2836 oop thread_obj = threadObj(); 2837 if (thread_obj != NULL) { 2838 typeArrayOop name = java_lang_Thread::name(thread_obj); 2839 if (name != NULL) { 2840 if (buf == NULL) { 2841 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2842 } 2843 else { 2844 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2845 } 2846 } 2847 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2848 name_str = "<no-name - thread is attaching>"; 2849 } 2850 else { 2851 name_str = Thread::name(); 2852 } 2853 } 2854 else { 2855 name_str = Thread::name(); 2856 } 2857 assert(name_str != NULL, "unexpected NULL thread name"); 2858 return name_str; 2859} 2860 2861 2862const char* JavaThread::get_threadgroup_name() const { 2863 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2864 oop thread_obj = threadObj(); 2865 if (thread_obj != NULL) { 2866 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2867 if (thread_group != NULL) { 2868 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2869 // ThreadGroup.name can be null 2870 if (name != NULL) { 2871 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2872 return str; 2873 } 2874 } 2875 } 2876 return NULL; 2877} 2878 2879const char* JavaThread::get_parent_name() const { 2880 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2881 oop thread_obj = threadObj(); 2882 if (thread_obj != NULL) { 2883 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2884 if (thread_group != NULL) { 2885 oop parent = java_lang_ThreadGroup::parent(thread_group); 2886 if (parent != NULL) { 2887 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2888 // ThreadGroup.name can be null 2889 if (name != NULL) { 2890 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2891 return str; 2892 } 2893 } 2894 } 2895 } 2896 return NULL; 2897} 2898 2899ThreadPriority JavaThread::java_priority() const { 2900 oop thr_oop = threadObj(); 2901 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2902 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2903 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2904 return priority; 2905} 2906 2907void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2908 2909 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2910 // Link Java Thread object <-> C++ Thread 2911 2912 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2913 // and put it into a new Handle. The Handle "thread_oop" can then 2914 // be used to pass the C++ thread object to other methods. 2915 2916 // Set the Java level thread object (jthread) field of the 2917 // new thread (a JavaThread *) to C++ thread object using the 2918 // "thread_oop" handle. 2919 2920 // Set the thread field (a JavaThread *) of the 2921 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2922 2923 Handle thread_oop(Thread::current(), 2924 JNIHandles::resolve_non_null(jni_thread)); 2925 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 2926 "must be initialized"); 2927 set_threadObj(thread_oop()); 2928 java_lang_Thread::set_thread(thread_oop(), this); 2929 2930 if (prio == NoPriority) { 2931 prio = java_lang_Thread::priority(thread_oop()); 2932 assert(prio != NoPriority, "A valid priority should be present"); 2933 } 2934 2935 // Push the Java priority down to the native thread; needs Threads_lock 2936 Thread::set_priority(this, prio); 2937 2938 // Add the new thread to the Threads list and set it in motion. 2939 // We must have threads lock in order to call Threads::add. 2940 // It is crucial that we do not block before the thread is 2941 // added to the Threads list for if a GC happens, then the java_thread oop 2942 // will not be visited by GC. 2943 Threads::add(this); 2944} 2945 2946oop JavaThread::current_park_blocker() { 2947 // Support for JSR-166 locks 2948 oop thread_oop = threadObj(); 2949 if (thread_oop != NULL && 2950 JDK_Version::current().supports_thread_park_blocker()) { 2951 return java_lang_Thread::park_blocker(thread_oop); 2952 } 2953 return NULL; 2954} 2955 2956 2957void JavaThread::print_stack_on(outputStream* st) { 2958 if (!has_last_Java_frame()) return; 2959 ResourceMark rm; 2960 HandleMark hm; 2961 2962 RegisterMap reg_map(this); 2963 vframe* start_vf = last_java_vframe(®_map); 2964 int count = 0; 2965 for (vframe* f = start_vf; f; f = f->sender() ) { 2966 if (f->is_java_frame()) { 2967 javaVFrame* jvf = javaVFrame::cast(f); 2968 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 2969 2970 // Print out lock information 2971 if (JavaMonitorsInStackTrace) { 2972 jvf->print_lock_info_on(st, count); 2973 } 2974 } else { 2975 // Ignore non-Java frames 2976 } 2977 2978 // Bail-out case for too deep stacks 2979 count++; 2980 if (MaxJavaStackTraceDepth == count) return; 2981 } 2982} 2983 2984 2985// JVMTI PopFrame support 2986void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 2987 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 2988 if (in_bytes(size_in_bytes) != 0) { 2989 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 2990 _popframe_preserved_args_size = in_bytes(size_in_bytes); 2991 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 2992 } 2993} 2994 2995void* JavaThread::popframe_preserved_args() { 2996 return _popframe_preserved_args; 2997} 2998 2999ByteSize JavaThread::popframe_preserved_args_size() { 3000 return in_ByteSize(_popframe_preserved_args_size); 3001} 3002 3003WordSize JavaThread::popframe_preserved_args_size_in_words() { 3004 int sz = in_bytes(popframe_preserved_args_size()); 3005 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3006 return in_WordSize(sz / wordSize); 3007} 3008 3009void JavaThread::popframe_free_preserved_args() { 3010 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3011 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3012 _popframe_preserved_args = NULL; 3013 _popframe_preserved_args_size = 0; 3014} 3015 3016#ifndef PRODUCT 3017 3018void JavaThread::trace_frames() { 3019 tty->print_cr("[Describe stack]"); 3020 int frame_no = 1; 3021 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3022 tty->print(" %d. ", frame_no++); 3023 fst.current()->print_value_on(tty,this); 3024 tty->cr(); 3025 } 3026} 3027 3028class PrintAndVerifyOopClosure: public OopClosure { 3029 protected: 3030 template <class T> inline void do_oop_work(T* p) { 3031 oop obj = oopDesc::load_decode_heap_oop(p); 3032 if (obj == NULL) return; 3033 tty->print(INTPTR_FORMAT ": ", p); 3034 if (obj->is_oop_or_null()) { 3035 if (obj->is_objArray()) { 3036 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3037 } else { 3038 obj->print(); 3039 } 3040 } else { 3041 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3042 } 3043 tty->cr(); 3044 } 3045 public: 3046 virtual void do_oop(oop* p) { do_oop_work(p); } 3047 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3048}; 3049 3050 3051static void oops_print(frame* f, const RegisterMap *map) { 3052 PrintAndVerifyOopClosure print; 3053 f->print_value(); 3054 f->oops_do(&print, NULL, (RegisterMap*)map); 3055} 3056 3057// Print our all the locations that contain oops and whether they are 3058// valid or not. This useful when trying to find the oldest frame 3059// where an oop has gone bad since the frame walk is from youngest to 3060// oldest. 3061void JavaThread::trace_oops() { 3062 tty->print_cr("[Trace oops]"); 3063 frames_do(oops_print); 3064} 3065 3066 3067#ifdef ASSERT 3068// Print or validate the layout of stack frames 3069void JavaThread::print_frame_layout(int depth, bool validate_only) { 3070 ResourceMark rm; 3071 PRESERVE_EXCEPTION_MARK; 3072 FrameValues values; 3073 int frame_no = 0; 3074 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3075 fst.current()->describe(values, ++frame_no); 3076 if (depth == frame_no) break; 3077 } 3078 if (validate_only) { 3079 values.validate(); 3080 } else { 3081 tty->print_cr("[Describe stack layout]"); 3082 values.print(this); 3083 } 3084} 3085#endif 3086 3087void JavaThread::trace_stack_from(vframe* start_vf) { 3088 ResourceMark rm; 3089 int vframe_no = 1; 3090 for (vframe* f = start_vf; f; f = f->sender() ) { 3091 if (f->is_java_frame()) { 3092 javaVFrame::cast(f)->print_activation(vframe_no++); 3093 } else { 3094 f->print(); 3095 } 3096 if (vframe_no > StackPrintLimit) { 3097 tty->print_cr("...<more frames>..."); 3098 return; 3099 } 3100 } 3101} 3102 3103 3104void JavaThread::trace_stack() { 3105 if (!has_last_Java_frame()) return; 3106 ResourceMark rm; 3107 HandleMark hm; 3108 RegisterMap reg_map(this); 3109 trace_stack_from(last_java_vframe(®_map)); 3110} 3111 3112 3113#endif // PRODUCT 3114 3115 3116javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3117 assert(reg_map != NULL, "a map must be given"); 3118 frame f = last_frame(); 3119 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3120 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3121 } 3122 return NULL; 3123} 3124 3125 3126Klass* JavaThread::security_get_caller_class(int depth) { 3127 vframeStream vfst(this); 3128 vfst.security_get_caller_frame(depth); 3129 if (!vfst.at_end()) { 3130 return vfst.method()->method_holder(); 3131 } 3132 return NULL; 3133} 3134 3135static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3136 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3137 CompileBroker::compiler_thread_loop(); 3138} 3139 3140// Create a CompilerThread 3141CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3142: JavaThread(&compiler_thread_entry) { 3143 _env = NULL; 3144 _log = NULL; 3145 _task = NULL; 3146 _queue = queue; 3147 _counters = counters; 3148 _buffer_blob = NULL; 3149 _scanned_nmethod = NULL; 3150 3151#ifndef PRODUCT 3152 _ideal_graph_printer = NULL; 3153#endif 3154} 3155 3156void CompilerThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 3157 JavaThread::oops_do(f, cf); 3158 if (_scanned_nmethod != NULL && cf != NULL) { 3159 // Safepoints can occur when the sweeper is scanning an nmethod so 3160 // process it here to make sure it isn't unloaded in the middle of 3161 // a scan. 3162 cf->do_code_blob(_scanned_nmethod); 3163 } 3164} 3165 3166// ======= Threads ======== 3167 3168// The Threads class links together all active threads, and provides 3169// operations over all threads. It is protected by its own Mutex 3170// lock, which is also used in other contexts to protect thread 3171// operations from having the thread being operated on from exiting 3172// and going away unexpectedly (e.g., safepoint synchronization) 3173 3174JavaThread* Threads::_thread_list = NULL; 3175int Threads::_number_of_threads = 0; 3176int Threads::_number_of_non_daemon_threads = 0; 3177int Threads::_return_code = 0; 3178size_t JavaThread::_stack_size_at_create = 0; 3179#ifdef ASSERT 3180bool Threads::_vm_complete = false; 3181#endif 3182 3183// All JavaThreads 3184#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3185 3186void os_stream(); 3187 3188// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3189void Threads::threads_do(ThreadClosure* tc) { 3190 assert_locked_or_safepoint(Threads_lock); 3191 // ALL_JAVA_THREADS iterates through all JavaThreads 3192 ALL_JAVA_THREADS(p) { 3193 tc->do_thread(p); 3194 } 3195 // Someday we could have a table or list of all non-JavaThreads. 3196 // For now, just manually iterate through them. 3197 tc->do_thread(VMThread::vm_thread()); 3198 Universe::heap()->gc_threads_do(tc); 3199 WatcherThread *wt = WatcherThread::watcher_thread(); 3200 // Strictly speaking, the following NULL check isn't sufficient to make sure 3201 // the data for WatcherThread is still valid upon being examined. However, 3202 // considering that WatchThread terminates when the VM is on the way to 3203 // exit at safepoint, the chance of the above is extremely small. The right 3204 // way to prevent termination of WatcherThread would be to acquire 3205 // Terminator_lock, but we can't do that without violating the lock rank 3206 // checking in some cases. 3207 if (wt != NULL) 3208 tc->do_thread(wt); 3209 3210 // If CompilerThreads ever become non-JavaThreads, add them here 3211} 3212 3213jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3214 3215 extern void JDK_Version_init(); 3216 3217 // Check version 3218 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3219 3220 // Initialize the output stream module 3221 ostream_init(); 3222 3223 // Process java launcher properties. 3224 Arguments::process_sun_java_launcher_properties(args); 3225 3226 // Initialize the os module before using TLS 3227 os::init(); 3228 3229 // Initialize system properties. 3230 Arguments::init_system_properties(); 3231 3232 // So that JDK version can be used as a discrimintor when parsing arguments 3233 JDK_Version_init(); 3234 3235 // Update/Initialize System properties after JDK version number is known 3236 Arguments::init_version_specific_system_properties(); 3237 3238 // Parse arguments 3239 jint parse_result = Arguments::parse(args); 3240 if (parse_result != JNI_OK) return parse_result; 3241 3242 if (PauseAtStartup) { 3243 os::pause(); 3244 } 3245 3246#ifndef USDT2 3247 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3248#else /* USDT2 */ 3249 HOTSPOT_VM_INIT_BEGIN(); 3250#endif /* USDT2 */ 3251 3252 // Record VM creation timing statistics 3253 TraceVmCreationTime create_vm_timer; 3254 create_vm_timer.start(); 3255 3256 // Timing (must come after argument parsing) 3257 TraceTime timer("Create VM", TraceStartupTime); 3258 3259 // Initialize the os module after parsing the args 3260 jint os_init_2_result = os::init_2(); 3261 if (os_init_2_result != JNI_OK) return os_init_2_result; 3262 3263 // intialize TLS 3264 ThreadLocalStorage::init(); 3265 3266 // Bootstrap native memory tracking, so it can start recording memory 3267 // activities before worker thread is started. This is the first phase 3268 // of bootstrapping, VM is currently running in single-thread mode. 3269 MemTracker::bootstrap_single_thread(); 3270 3271 // Initialize output stream logging 3272 ostream_init_log(); 3273 3274 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3275 // Must be before create_vm_init_agents() 3276 if (Arguments::init_libraries_at_startup()) { 3277 convert_vm_init_libraries_to_agents(); 3278 } 3279 3280 // Launch -agentlib/-agentpath and converted -Xrun agents 3281 if (Arguments::init_agents_at_startup()) { 3282 create_vm_init_agents(); 3283 } 3284 3285 // Initialize Threads state 3286 _thread_list = NULL; 3287 _number_of_threads = 0; 3288 _number_of_non_daemon_threads = 0; 3289 3290 // Initialize global data structures and create system classes in heap 3291 vm_init_globals(); 3292 3293 // Attach the main thread to this os thread 3294 JavaThread* main_thread = new JavaThread(); 3295 main_thread->set_thread_state(_thread_in_vm); 3296 // must do this before set_active_handles and initialize_thread_local_storage 3297 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3298 // change the stack size recorded here to one based on the java thread 3299 // stacksize. This adjusted size is what is used to figure the placement 3300 // of the guard pages. 3301 main_thread->record_stack_base_and_size(); 3302 main_thread->initialize_thread_local_storage(); 3303 3304 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3305 3306 if (!main_thread->set_as_starting_thread()) { 3307 vm_shutdown_during_initialization( 3308 "Failed necessary internal allocation. Out of swap space"); 3309 delete main_thread; 3310 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3311 return JNI_ENOMEM; 3312 } 3313 3314 // Enable guard page *after* os::create_main_thread(), otherwise it would 3315 // crash Linux VM, see notes in os_linux.cpp. 3316 main_thread->create_stack_guard_pages(); 3317 3318 // Initialize Java-Level synchronization subsystem 3319 ObjectMonitor::Initialize() ; 3320 3321 // Second phase of bootstrapping, VM is about entering multi-thread mode 3322 MemTracker::bootstrap_multi_thread(); 3323 3324 // Initialize global modules 3325 jint status = init_globals(); 3326 if (status != JNI_OK) { 3327 delete main_thread; 3328 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3329 return status; 3330 } 3331 3332 // Should be done after the heap is fully created 3333 main_thread->cache_global_variables(); 3334 3335 HandleMark hm; 3336 3337 { MutexLocker mu(Threads_lock); 3338 Threads::add(main_thread); 3339 } 3340 3341 // Any JVMTI raw monitors entered in onload will transition into 3342 // real raw monitor. VM is setup enough here for raw monitor enter. 3343 JvmtiExport::transition_pending_onload_raw_monitors(); 3344 3345 if (VerifyBeforeGC && 3346 Universe::heap()->total_collections() >= VerifyGCStartAt) { 3347 Universe::heap()->prepare_for_verify(); 3348 Universe::verify(); // make sure we're starting with a clean slate 3349 } 3350 3351 // Fully start NMT 3352 MemTracker::start(); 3353 3354 // Create the VMThread 3355 { TraceTime timer("Start VMThread", TraceStartupTime); 3356 VMThread::create(); 3357 Thread* vmthread = VMThread::vm_thread(); 3358 3359 if (!os::create_thread(vmthread, os::vm_thread)) 3360 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3361 3362 // Wait for the VM thread to become ready, and VMThread::run to initialize 3363 // Monitors can have spurious returns, must always check another state flag 3364 { 3365 MutexLocker ml(Notify_lock); 3366 os::start_thread(vmthread); 3367 while (vmthread->active_handles() == NULL) { 3368 Notify_lock->wait(); 3369 } 3370 } 3371 } 3372 3373 assert (Universe::is_fully_initialized(), "not initialized"); 3374 EXCEPTION_MARK; 3375 3376 // At this point, the Universe is initialized, but we have not executed 3377 // any byte code. Now is a good time (the only time) to dump out the 3378 // internal state of the JVM for sharing. 3379 if (DumpSharedSpaces) { 3380 MetaspaceShared::preload_and_dump(CHECK_0); 3381 ShouldNotReachHere(); 3382 } 3383 3384 // Always call even when there are not JVMTI environments yet, since environments 3385 // may be attached late and JVMTI must track phases of VM execution 3386 JvmtiExport::enter_start_phase(); 3387 3388 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3389 JvmtiExport::post_vm_start(); 3390 3391 { 3392 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3393 3394 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3395 create_vm_init_libraries(); 3396 } 3397 3398 if (InitializeJavaLangString) { 3399 initialize_class(vmSymbols::java_lang_String(), CHECK_0); 3400 } else { 3401 warning("java.lang.String not initialized"); 3402 } 3403 3404 if (AggressiveOpts) { 3405 { 3406 // Forcibly initialize java/util/HashMap and mutate the private 3407 // static final "frontCacheEnabled" field before we start creating instances 3408#ifdef ASSERT 3409 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3410 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 3411#endif 3412 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3413 KlassHandle k = KlassHandle(THREAD, k_o); 3414 guarantee(k.not_null(), "Must find java/util/HashMap"); 3415 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3416 ik->initialize(CHECK_0); 3417 fieldDescriptor fd; 3418 // Possible we might not find this field; if so, don't break 3419 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3420 k()->java_mirror()->bool_field_put(fd.offset(), true); 3421 } 3422 } 3423 3424 if (UseStringCache) { 3425 // Forcibly initialize java/lang/StringValue and mutate the private 3426 // static final "stringCacheEnabled" field before we start creating instances 3427 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0); 3428 // Possible that StringValue isn't present: if so, silently don't break 3429 if (k_o != NULL) { 3430 KlassHandle k = KlassHandle(THREAD, k_o); 3431 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3432 ik->initialize(CHECK_0); 3433 fieldDescriptor fd; 3434 // Possible we might not find this field: if so, silently don't break 3435 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3436 k()->java_mirror()->bool_field_put(fd.offset(), true); 3437 } 3438 } 3439 } 3440 } 3441 3442 // Initialize java_lang.System (needed before creating the thread) 3443 if (InitializeJavaLangSystem) { 3444 initialize_class(vmSymbols::java_lang_System(), CHECK_0); 3445 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0); 3446 Handle thread_group = create_initial_thread_group(CHECK_0); 3447 Universe::set_main_thread_group(thread_group()); 3448 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0); 3449 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 3450 main_thread->set_threadObj(thread_object); 3451 // Set thread status to running since main thread has 3452 // been started and running. 3453 java_lang_Thread::set_thread_status(thread_object, 3454 java_lang_Thread::RUNNABLE); 3455 3456 // The VM preresolve methods to these classes. Make sure that get initialized 3457 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0); 3458 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0); 3459 // The VM creates & returns objects of this class. Make sure it's initialized. 3460 initialize_class(vmSymbols::java_lang_Class(), CHECK_0); 3461 call_initializeSystemClass(CHECK_0); 3462 3463 // get the Java runtime name after java.lang.System is initialized 3464 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3465 } else { 3466 warning("java.lang.System not initialized"); 3467 } 3468 3469 // an instance of OutOfMemory exception has been allocated earlier 3470 if (InitializeJavaLangExceptionsErrors) { 3471 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0); 3472 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0); 3473 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0); 3474 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0); 3475 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0); 3476 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0); 3477 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0); 3478 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0); 3479 } else { 3480 warning("java.lang.OutOfMemoryError has not been initialized"); 3481 warning("java.lang.NullPointerException has not been initialized"); 3482 warning("java.lang.ClassCastException has not been initialized"); 3483 warning("java.lang.ArrayStoreException has not been initialized"); 3484 warning("java.lang.ArithmeticException has not been initialized"); 3485 warning("java.lang.StackOverflowError has not been initialized"); 3486 warning("java.lang.IllegalArgumentException has not been initialized"); 3487 } 3488 } 3489 3490 // See : bugid 4211085. 3491 // Background : the static initializer of java.lang.Compiler tries to read 3492 // property"java.compiler" and read & write property "java.vm.info". 3493 // When a security manager is installed through the command line 3494 // option "-Djava.security.manager", the above properties are not 3495 // readable and the static initializer for java.lang.Compiler fails 3496 // resulting in a NoClassDefFoundError. This can happen in any 3497 // user code which calls methods in java.lang.Compiler. 3498 // Hack : the hack is to pre-load and initialize this class, so that only 3499 // system domains are on the stack when the properties are read. 3500 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3501 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3502 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3503 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3504 // Once that is done, we should remove this hack. 3505 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0); 3506 3507 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3508 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3509 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3510 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3511 // This should also be taken out as soon as 4211383 gets fixed. 3512 reset_vm_info_property(CHECK_0); 3513 3514 quicken_jni_functions(); 3515 3516 // Must be run after init_ft which initializes ft_enabled 3517 if (TRACE_INITIALIZE() != JNI_OK) { 3518 vm_exit_during_initialization("Failed to initialize tracing backend"); 3519 } 3520 3521 // Set flag that basic initialization has completed. Used by exceptions and various 3522 // debug stuff, that does not work until all basic classes have been initialized. 3523 set_init_completed(); 3524 3525#ifndef USDT2 3526 HS_DTRACE_PROBE(hotspot, vm__init__end); 3527#else /* USDT2 */ 3528 HOTSPOT_VM_INIT_END(); 3529#endif /* USDT2 */ 3530 3531 // record VM initialization completion time 3532 Management::record_vm_init_completed(); 3533 3534 // Compute system loader. Note that this has to occur after set_init_completed, since 3535 // valid exceptions may be thrown in the process. 3536 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3537 // set_init_completed has just been called, causing exceptions not to be shortcut 3538 // anymore. We call vm_exit_during_initialization directly instead. 3539 SystemDictionary::compute_java_system_loader(THREAD); 3540 if (HAS_PENDING_EXCEPTION) { 3541 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3542 } 3543 3544#ifndef SERIALGC 3545 // Support for ConcurrentMarkSweep. This should be cleaned up 3546 // and better encapsulated. The ugly nested if test would go away 3547 // once things are properly refactored. XXX YSR 3548 if (UseConcMarkSweepGC || UseG1GC) { 3549 if (UseConcMarkSweepGC) { 3550 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3551 } else { 3552 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3553 } 3554 if (HAS_PENDING_EXCEPTION) { 3555 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3556 } 3557 } 3558#endif // SERIALGC 3559 3560 // Always call even when there are not JVMTI environments yet, since environments 3561 // may be attached late and JVMTI must track phases of VM execution 3562 JvmtiExport::enter_live_phase(); 3563 3564 // Signal Dispatcher needs to be started before VMInit event is posted 3565 os::signal_init(); 3566 3567 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3568 if (!DisableAttachMechanism) { 3569 if (StartAttachListener || AttachListener::init_at_startup()) { 3570 AttachListener::init(); 3571 } 3572 } 3573 3574 // Launch -Xrun agents 3575 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3576 // back-end can launch with -Xdebug -Xrunjdwp. 3577 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3578 create_vm_init_libraries(); 3579 } 3580 3581 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3582 JvmtiExport::post_vm_initialized(); 3583 3584 if (!TRACE_START()) { 3585 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3586 } 3587 3588 if (CleanChunkPoolAsync) { 3589 Chunk::start_chunk_pool_cleaner_task(); 3590 } 3591 3592 // initialize compiler(s) 3593 CompileBroker::compilation_init(); 3594 3595 Management::initialize(THREAD); 3596 if (HAS_PENDING_EXCEPTION) { 3597 // management agent fails to start possibly due to 3598 // configuration problem and is responsible for printing 3599 // stack trace if appropriate. Simply exit VM. 3600 vm_exit(1); 3601 } 3602 3603 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3604 if (Arguments::has_alloc_profile()) AllocationProfiler::engage(); 3605 if (MemProfiling) MemProfiler::engage(); 3606 StatSampler::engage(); 3607 if (CheckJNICalls) JniPeriodicChecker::engage(); 3608 3609 BiasedLocking::init(); 3610 3611 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3612 call_postVMInitHook(THREAD); 3613 // The Java side of PostVMInitHook.run must deal with all 3614 // exceptions and provide means of diagnosis. 3615 if (HAS_PENDING_EXCEPTION) { 3616 CLEAR_PENDING_EXCEPTION; 3617 } 3618 } 3619 3620 // Start up the WatcherThread if there are any periodic tasks 3621 // NOTE: All PeriodicTasks should be registered by now. If they 3622 // aren't, late joiners might appear to start slowly (we might 3623 // take a while to process their first tick). 3624 if (PeriodicTask::num_tasks() > 0) { 3625 WatcherThread::start(); 3626 } 3627 3628 // Give os specific code one last chance to start 3629 os::init_3(); 3630 3631 create_vm_timer.end(); 3632#ifdef ASSERT 3633 _vm_complete = true; 3634#endif 3635 return JNI_OK; 3636} 3637 3638// type for the Agent_OnLoad and JVM_OnLoad entry points 3639extern "C" { 3640 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3641} 3642// Find a command line agent library and return its entry point for 3643// -agentlib: -agentpath: -Xrun 3644// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3645static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3646 OnLoadEntry_t on_load_entry = NULL; 3647 void *library = agent->os_lib(); // check if we have looked it up before 3648 3649 if (library == NULL) { 3650 char buffer[JVM_MAXPATHLEN]; 3651 char ebuf[1024]; 3652 const char *name = agent->name(); 3653 const char *msg = "Could not find agent library "; 3654 3655 if (agent->is_absolute_path()) { 3656 library = os::dll_load(name, ebuf, sizeof ebuf); 3657 if (library == NULL) { 3658 const char *sub_msg = " in absolute path, with error: "; 3659 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3660 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3661 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3662 // If we can't find the agent, exit. 3663 vm_exit_during_initialization(buf, NULL); 3664 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3665 } 3666 } else { 3667 // Try to load the agent from the standard dll directory 3668 os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name); 3669 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3670#ifdef KERNEL 3671 // Download instrument dll 3672 if (library == NULL && strcmp(name, "instrument") == 0) { 3673 char *props = Arguments::get_kernel_properties(); 3674 char *home = Arguments::get_java_home(); 3675 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false" 3676 " sun.jkernel.DownloadManager -download client_jvm"; 3677 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1; 3678 char *cmd = NEW_C_HEAP_ARRAY(char, length, mtThread); 3679 jio_snprintf(cmd, length, fmt, home, props); 3680 int status = os::fork_and_exec(cmd); 3681 FreeHeap(props); 3682 if (status == -1) { 3683 warning(cmd); 3684 vm_exit_during_initialization("fork_and_exec failed: %s", 3685 strerror(errno)); 3686 } 3687 FREE_C_HEAP_ARRAY(char, cmd, mtThread); 3688 // when this comes back the instrument.dll should be where it belongs. 3689 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3690 } 3691#endif // KERNEL 3692 if (library == NULL) { // Try the local directory 3693 char ns[1] = {0}; 3694 os::dll_build_name(buffer, sizeof(buffer), ns, name); 3695 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3696 if (library == NULL) { 3697 const char *sub_msg = " on the library path, with error: "; 3698 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3699 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3700 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3701 // If we can't find the agent, exit. 3702 vm_exit_during_initialization(buf, NULL); 3703 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3704 } 3705 } 3706 } 3707 agent->set_os_lib(library); 3708 } 3709 3710 // Find the OnLoad function. 3711 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3712 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index])); 3713 if (on_load_entry != NULL) break; 3714 } 3715 return on_load_entry; 3716} 3717 3718// Find the JVM_OnLoad entry point 3719static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3720 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3721 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3722} 3723 3724// Find the Agent_OnLoad entry point 3725static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3726 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3727 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3728} 3729 3730// For backwards compatibility with -Xrun 3731// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3732// treated like -agentpath: 3733// Must be called before agent libraries are created 3734void Threads::convert_vm_init_libraries_to_agents() { 3735 AgentLibrary* agent; 3736 AgentLibrary* next; 3737 3738 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3739 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3740 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3741 3742 // If there is an JVM_OnLoad function it will get called later, 3743 // otherwise see if there is an Agent_OnLoad 3744 if (on_load_entry == NULL) { 3745 on_load_entry = lookup_agent_on_load(agent); 3746 if (on_load_entry != NULL) { 3747 // switch it to the agent list -- so that Agent_OnLoad will be called, 3748 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3749 Arguments::convert_library_to_agent(agent); 3750 } else { 3751 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3752 } 3753 } 3754 } 3755} 3756 3757// Create agents for -agentlib: -agentpath: and converted -Xrun 3758// Invokes Agent_OnLoad 3759// Called very early -- before JavaThreads exist 3760void Threads::create_vm_init_agents() { 3761 extern struct JavaVM_ main_vm; 3762 AgentLibrary* agent; 3763 3764 JvmtiExport::enter_onload_phase(); 3765 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3766 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3767 3768 if (on_load_entry != NULL) { 3769 // Invoke the Agent_OnLoad function 3770 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3771 if (err != JNI_OK) { 3772 vm_exit_during_initialization("agent library failed to init", agent->name()); 3773 } 3774 } else { 3775 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3776 } 3777 } 3778 JvmtiExport::enter_primordial_phase(); 3779} 3780 3781extern "C" { 3782 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3783} 3784 3785void Threads::shutdown_vm_agents() { 3786 // Send any Agent_OnUnload notifications 3787 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3788 extern struct JavaVM_ main_vm; 3789 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3790 3791 // Find the Agent_OnUnload function. 3792 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3793 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3794 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3795 3796 // Invoke the Agent_OnUnload function 3797 if (unload_entry != NULL) { 3798 JavaThread* thread = JavaThread::current(); 3799 ThreadToNativeFromVM ttn(thread); 3800 HandleMark hm(thread); 3801 (*unload_entry)(&main_vm); 3802 break; 3803 } 3804 } 3805 } 3806} 3807 3808// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3809// Invokes JVM_OnLoad 3810void Threads::create_vm_init_libraries() { 3811 extern struct JavaVM_ main_vm; 3812 AgentLibrary* agent; 3813 3814 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3815 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3816 3817 if (on_load_entry != NULL) { 3818 // Invoke the JVM_OnLoad function 3819 JavaThread* thread = JavaThread::current(); 3820 ThreadToNativeFromVM ttn(thread); 3821 HandleMark hm(thread); 3822 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3823 if (err != JNI_OK) { 3824 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3825 } 3826 } else { 3827 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3828 } 3829 } 3830} 3831 3832// Last thread running calls java.lang.Shutdown.shutdown() 3833void JavaThread::invoke_shutdown_hooks() { 3834 HandleMark hm(this); 3835 3836 // We could get here with a pending exception, if so clear it now. 3837 if (this->has_pending_exception()) { 3838 this->clear_pending_exception(); 3839 } 3840 3841 EXCEPTION_MARK; 3842 Klass* k = 3843 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3844 THREAD); 3845 if (k != NULL) { 3846 // SystemDictionary::resolve_or_null will return null if there was 3847 // an exception. If we cannot load the Shutdown class, just don't 3848 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3849 // and finalizers (if runFinalizersOnExit is set) won't be run. 3850 // Note that if a shutdown hook was registered or runFinalizersOnExit 3851 // was called, the Shutdown class would have already been loaded 3852 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3853 instanceKlassHandle shutdown_klass (THREAD, k); 3854 JavaValue result(T_VOID); 3855 JavaCalls::call_static(&result, 3856 shutdown_klass, 3857 vmSymbols::shutdown_method_name(), 3858 vmSymbols::void_method_signature(), 3859 THREAD); 3860 } 3861 CLEAR_PENDING_EXCEPTION; 3862} 3863 3864// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3865// the program falls off the end of main(). Another VM exit path is through 3866// vm_exit() when the program calls System.exit() to return a value or when 3867// there is a serious error in VM. The two shutdown paths are not exactly 3868// the same, but they share Shutdown.shutdown() at Java level and before_exit() 3869// and VM_Exit op at VM level. 3870// 3871// Shutdown sequence: 3872// + Shutdown native memory tracking if it is on 3873// + Wait until we are the last non-daemon thread to execute 3874// <-- every thing is still working at this moment --> 3875// + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3876// shutdown hooks, run finalizers if finalization-on-exit 3877// + Call before_exit(), prepare for VM exit 3878// > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3879// currently the only user of this mechanism is File.deleteOnExit()) 3880// > stop flat profiler, StatSampler, watcher thread, CMS threads, 3881// post thread end and vm death events to JVMTI, 3882// stop signal thread 3883// + Call JavaThread::exit(), it will: 3884// > release JNI handle blocks, remove stack guard pages 3885// > remove this thread from Threads list 3886// <-- no more Java code from this thread after this point --> 3887// + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3888// the compiler threads at safepoint 3889// <-- do not use anything that could get blocked by Safepoint --> 3890// + Disable tracing at JNI/JVM barriers 3891// + Set _vm_exited flag for threads that are still running native code 3892// + Delete this thread 3893// + Call exit_globals() 3894// > deletes tty 3895// > deletes PerfMemory resources 3896// + Return to caller 3897 3898bool Threads::destroy_vm() { 3899 JavaThread* thread = JavaThread::current(); 3900 3901#ifdef ASSERT 3902 _vm_complete = false; 3903#endif 3904 // Wait until we are the last non-daemon thread to execute 3905 { MutexLocker nu(Threads_lock); 3906 while (Threads::number_of_non_daemon_threads() > 1 ) 3907 // This wait should make safepoint checks, wait without a timeout, 3908 // and wait as a suspend-equivalent condition. 3909 // 3910 // Note: If the FlatProfiler is running and this thread is waiting 3911 // for another non-daemon thread to finish, then the FlatProfiler 3912 // is waiting for the external suspend request on this thread to 3913 // complete. wait_for_ext_suspend_completion() will eventually 3914 // timeout, but that takes time. Making this wait a suspend- 3915 // equivalent condition solves that timeout problem. 3916 // 3917 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3918 Mutex::_as_suspend_equivalent_flag); 3919 } 3920 3921 // Shutdown NMT before exit. Otherwise, 3922 // it will run into trouble when system destroys static variables. 3923 MemTracker::shutdown(MemTracker::NMT_normal); 3924 3925 // Hang forever on exit if we are reporting an error. 3926 if (ShowMessageBoxOnError && is_error_reported()) { 3927 os::infinite_sleep(); 3928 } 3929 os::wait_for_keypress_at_exit(); 3930 3931 if (JDK_Version::is_jdk12x_version()) { 3932 // We are the last thread running, so check if finalizers should be run. 3933 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3934 HandleMark rm(thread); 3935 Universe::run_finalizers_on_exit(); 3936 } else { 3937 // run Java level shutdown hooks 3938 thread->invoke_shutdown_hooks(); 3939 } 3940 3941 before_exit(thread); 3942 3943 thread->exit(true); 3944 3945 // Stop VM thread. 3946 { 3947 // 4945125 The vm thread comes to a safepoint during exit. 3948 // GC vm_operations can get caught at the safepoint, and the 3949 // heap is unparseable if they are caught. Grab the Heap_lock 3950 // to prevent this. The GC vm_operations will not be able to 3951 // queue until after the vm thread is dead. 3952 // After this point, we'll never emerge out of the safepoint before 3953 // the VM exits, so concurrent GC threads do not need to be explicitly 3954 // stopped; they remain inactive until the process exits. 3955 // Note: some concurrent G1 threads may be running during a safepoint, 3956 // but these will not be accessing the heap, just some G1-specific side 3957 // data structures that are not accessed by any other threads but them 3958 // after this point in a terminal safepoint. 3959 3960 MutexLocker ml(Heap_lock); 3961 3962 VMThread::wait_for_vm_thread_exit(); 3963 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3964 VMThread::destroy(); 3965 } 3966 3967 // clean up ideal graph printers 3968#if defined(COMPILER2) && !defined(PRODUCT) 3969 IdealGraphPrinter::clean_up(); 3970#endif 3971 3972 // Now, all Java threads are gone except daemon threads. Daemon threads 3973 // running Java code or in VM are stopped by the Safepoint. However, 3974 // daemon threads executing native code are still running. But they 3975 // will be stopped at native=>Java/VM barriers. Note that we can't 3976 // simply kill or suspend them, as it is inherently deadlock-prone. 3977 3978#ifndef PRODUCT 3979 // disable function tracing at JNI/JVM barriers 3980 TraceJNICalls = false; 3981 TraceJVMCalls = false; 3982 TraceRuntimeCalls = false; 3983#endif 3984 3985 VM_Exit::set_vm_exited(); 3986 3987 notify_vm_shutdown(); 3988 3989 delete thread; 3990 3991 // exit_globals() will delete tty 3992 exit_globals(); 3993 3994 return true; 3995} 3996 3997 3998jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 3999 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4000 return is_supported_jni_version(version); 4001} 4002 4003 4004jboolean Threads::is_supported_jni_version(jint version) { 4005 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4006 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4007 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4008 return JNI_FALSE; 4009} 4010 4011 4012void Threads::add(JavaThread* p, bool force_daemon) { 4013 // The threads lock must be owned at this point 4014 assert_locked_or_safepoint(Threads_lock); 4015 4016 // See the comment for this method in thread.hpp for its purpose and 4017 // why it is called here. 4018 p->initialize_queues(); 4019 p->set_next(_thread_list); 4020 _thread_list = p; 4021 _number_of_threads++; 4022 oop threadObj = p->threadObj(); 4023 bool daemon = true; 4024 // Bootstrapping problem: threadObj can be null for initial 4025 // JavaThread (or for threads attached via JNI) 4026 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4027 _number_of_non_daemon_threads++; 4028 daemon = false; 4029 } 4030 4031 p->set_safepoint_visible(true); 4032 4033 ThreadService::add_thread(p, daemon); 4034 4035 // Possible GC point. 4036 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4037} 4038 4039void Threads::remove(JavaThread* p) { 4040 // Extra scope needed for Thread_lock, so we can check 4041 // that we do not remove thread without safepoint code notice 4042 { MutexLocker ml(Threads_lock); 4043 4044 assert(includes(p), "p must be present"); 4045 4046 JavaThread* current = _thread_list; 4047 JavaThread* prev = NULL; 4048 4049 while (current != p) { 4050 prev = current; 4051 current = current->next(); 4052 } 4053 4054 if (prev) { 4055 prev->set_next(current->next()); 4056 } else { 4057 _thread_list = p->next(); 4058 } 4059 _number_of_threads--; 4060 oop threadObj = p->threadObj(); 4061 bool daemon = true; 4062 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4063 _number_of_non_daemon_threads--; 4064 daemon = false; 4065 4066 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4067 // on destroy_vm will wake up. 4068 if (number_of_non_daemon_threads() == 1) 4069 Threads_lock->notify_all(); 4070 } 4071 ThreadService::remove_thread(p, daemon); 4072 4073 // Make sure that safepoint code disregard this thread. This is needed since 4074 // the thread might mess around with locks after this point. This can cause it 4075 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4076 // of this thread since it is removed from the queue. 4077 p->set_terminated_value(); 4078 4079 // Now, this thread is not visible to safepoint 4080 p->set_safepoint_visible(false); 4081 4082 } // unlock Threads_lock 4083 4084 // Since Events::log uses a lock, we grab it outside the Threads_lock 4085 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4086} 4087 4088// Threads_lock must be held when this is called (or must be called during a safepoint) 4089bool Threads::includes(JavaThread* p) { 4090 assert(Threads_lock->is_locked(), "sanity check"); 4091 ALL_JAVA_THREADS(q) { 4092 if (q == p ) { 4093 return true; 4094 } 4095 } 4096 return false; 4097} 4098 4099// Operations on the Threads list for GC. These are not explicitly locked, 4100// but the garbage collector must provide a safe context for them to run. 4101// In particular, these things should never be called when the Threads_lock 4102// is held by some other thread. (Note: the Safepoint abstraction also 4103// uses the Threads_lock to gurantee this property. It also makes sure that 4104// all threads gets blocked when exiting or starting). 4105 4106void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) { 4107 ALL_JAVA_THREADS(p) { 4108 p->oops_do(f, cf); 4109 } 4110 VMThread::vm_thread()->oops_do(f, cf); 4111} 4112 4113void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) { 4114 // Introduce a mechanism allowing parallel threads to claim threads as 4115 // root groups. Overhead should be small enough to use all the time, 4116 // even in sequential code. 4117 SharedHeap* sh = SharedHeap::heap(); 4118 // Cannot yet substitute active_workers for n_par_threads 4119 // because of G1CollectedHeap::verify() use of 4120 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4121 // turn off parallelism in process_strong_roots while active_workers 4122 // is being used for parallelism elsewhere. 4123 bool is_par = sh->n_par_threads() > 0; 4124 assert(!is_par || 4125 (SharedHeap::heap()->n_par_threads() == 4126 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4127 int cp = SharedHeap::heap()->strong_roots_parity(); 4128 ALL_JAVA_THREADS(p) { 4129 if (p->claim_oops_do(is_par, cp)) { 4130 p->oops_do(f, cf); 4131 } 4132 } 4133 VMThread* vmt = VMThread::vm_thread(); 4134 if (vmt->claim_oops_do(is_par, cp)) { 4135 vmt->oops_do(f, cf); 4136 } 4137} 4138 4139#ifndef SERIALGC 4140// Used by ParallelScavenge 4141void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4142 ALL_JAVA_THREADS(p) { 4143 q->enqueue(new ThreadRootsTask(p)); 4144 } 4145 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4146} 4147 4148// Used by Parallel Old 4149void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4150 ALL_JAVA_THREADS(p) { 4151 q->enqueue(new ThreadRootsMarkingTask(p)); 4152 } 4153 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4154} 4155#endif // SERIALGC 4156 4157void Threads::nmethods_do(CodeBlobClosure* cf) { 4158 ALL_JAVA_THREADS(p) { 4159 p->nmethods_do(cf); 4160 } 4161 VMThread::vm_thread()->nmethods_do(cf); 4162} 4163 4164void Threads::metadata_do(void f(Metadata*)) { 4165 ALL_JAVA_THREADS(p) { 4166 p->metadata_do(f); 4167 } 4168} 4169 4170void Threads::gc_epilogue() { 4171 ALL_JAVA_THREADS(p) { 4172 p->gc_epilogue(); 4173 } 4174} 4175 4176void Threads::gc_prologue() { 4177 ALL_JAVA_THREADS(p) { 4178 p->gc_prologue(); 4179 } 4180} 4181 4182void Threads::deoptimized_wrt_marked_nmethods() { 4183 ALL_JAVA_THREADS(p) { 4184 p->deoptimized_wrt_marked_nmethods(); 4185 } 4186} 4187 4188 4189// Get count Java threads that are waiting to enter the specified monitor. 4190GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4191 address monitor, bool doLock) { 4192 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4193 "must grab Threads_lock or be at safepoint"); 4194 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4195 4196 int i = 0; 4197 { 4198 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4199 ALL_JAVA_THREADS(p) { 4200 if (p->is_Compiler_thread()) continue; 4201 4202 address pending = (address)p->current_pending_monitor(); 4203 if (pending == monitor) { // found a match 4204 if (i < count) result->append(p); // save the first count matches 4205 i++; 4206 } 4207 } 4208 } 4209 return result; 4210} 4211 4212 4213JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4214 assert(doLock || 4215 Threads_lock->owned_by_self() || 4216 SafepointSynchronize::is_at_safepoint(), 4217 "must grab Threads_lock or be at safepoint"); 4218 4219 // NULL owner means not locked so we can skip the search 4220 if (owner == NULL) return NULL; 4221 4222 { 4223 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4224 ALL_JAVA_THREADS(p) { 4225 // first, see if owner is the address of a Java thread 4226 if (owner == (address)p) return p; 4227 } 4228 } 4229 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled"); 4230 if (UseHeavyMonitors) return NULL; 4231 4232 // 4233 // If we didn't find a matching Java thread and we didn't force use of 4234 // heavyweight monitors, then the owner is the stack address of the 4235 // Lock Word in the owning Java thread's stack. 4236 // 4237 JavaThread* the_owner = NULL; 4238 { 4239 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4240 ALL_JAVA_THREADS(q) { 4241 if (q->is_lock_owned(owner)) { 4242 the_owner = q; 4243 break; 4244 } 4245 } 4246 } 4247 assert(the_owner != NULL, "Did not find owning Java thread for lock word address"); 4248 return the_owner; 4249} 4250 4251// Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4252void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4253 char buf[32]; 4254 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4255 4256 st->print_cr("Full thread dump %s (%s %s):", 4257 Abstract_VM_Version::vm_name(), 4258 Abstract_VM_Version::vm_release(), 4259 Abstract_VM_Version::vm_info_string() 4260 ); 4261 st->cr(); 4262 4263#ifndef SERIALGC 4264 // Dump concurrent locks 4265 ConcurrentLocksDump concurrent_locks; 4266 if (print_concurrent_locks) { 4267 concurrent_locks.dump_at_safepoint(); 4268 } 4269#endif // SERIALGC 4270 4271 ALL_JAVA_THREADS(p) { 4272 ResourceMark rm; 4273 p->print_on(st); 4274 if (print_stacks) { 4275 if (internal_format) { 4276 p->trace_stack(); 4277 } else { 4278 p->print_stack_on(st); 4279 } 4280 } 4281 st->cr(); 4282#ifndef SERIALGC 4283 if (print_concurrent_locks) { 4284 concurrent_locks.print_locks_on(p, st); 4285 } 4286#endif // SERIALGC 4287 } 4288 4289 VMThread::vm_thread()->print_on(st); 4290 st->cr(); 4291 Universe::heap()->print_gc_threads_on(st); 4292 WatcherThread* wt = WatcherThread::watcher_thread(); 4293 if (wt != NULL) { 4294 wt->print_on(st); 4295 st->cr(); 4296 } 4297 CompileBroker::print_compiler_threads_on(st); 4298 st->flush(); 4299} 4300 4301// Threads::print_on_error() is called by fatal error handler. It's possible 4302// that VM is not at safepoint and/or current thread is inside signal handler. 4303// Don't print stack trace, as the stack may not be walkable. Don't allocate 4304// memory (even in resource area), it might deadlock the error handler. 4305void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4306 bool found_current = false; 4307 st->print_cr("Java Threads: ( => current thread )"); 4308 ALL_JAVA_THREADS(thread) { 4309 bool is_current = (current == thread); 4310 found_current = found_current || is_current; 4311 4312 st->print("%s", is_current ? "=>" : " "); 4313 4314 st->print(PTR_FORMAT, thread); 4315 st->print(" "); 4316 thread->print_on_error(st, buf, buflen); 4317 st->cr(); 4318 } 4319 st->cr(); 4320 4321 st->print_cr("Other Threads:"); 4322 if (VMThread::vm_thread()) { 4323 bool is_current = (current == VMThread::vm_thread()); 4324 found_current = found_current || is_current; 4325 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4326 4327 st->print(PTR_FORMAT, VMThread::vm_thread()); 4328 st->print(" "); 4329 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4330 st->cr(); 4331 } 4332 WatcherThread* wt = WatcherThread::watcher_thread(); 4333 if (wt != NULL) { 4334 bool is_current = (current == wt); 4335 found_current = found_current || is_current; 4336 st->print("%s", is_current ? "=>" : " "); 4337 4338 st->print(PTR_FORMAT, wt); 4339 st->print(" "); 4340 wt->print_on_error(st, buf, buflen); 4341 st->cr(); 4342 } 4343 if (!found_current) { 4344 st->cr(); 4345 st->print("=>" PTR_FORMAT " (exited) ", current); 4346 current->print_on_error(st, buf, buflen); 4347 st->cr(); 4348 } 4349} 4350 4351// Internal SpinLock and Mutex 4352// Based on ParkEvent 4353 4354// Ad-hoc mutual exclusion primitives: SpinLock and Mux 4355// 4356// We employ SpinLocks _only for low-contention, fixed-length 4357// short-duration critical sections where we're concerned 4358// about native mutex_t or HotSpot Mutex:: latency. 4359// The mux construct provides a spin-then-block mutual exclusion 4360// mechanism. 4361// 4362// Testing has shown that contention on the ListLock guarding gFreeList 4363// is common. If we implement ListLock as a simple SpinLock it's common 4364// for the JVM to devolve to yielding with little progress. This is true 4365// despite the fact that the critical sections protected by ListLock are 4366// extremely short. 4367// 4368// TODO-FIXME: ListLock should be of type SpinLock. 4369// We should make this a 1st-class type, integrated into the lock 4370// hierarchy as leaf-locks. Critically, the SpinLock structure 4371// should have sufficient padding to avoid false-sharing and excessive 4372// cache-coherency traffic. 4373 4374 4375typedef volatile int SpinLockT ; 4376 4377void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4378 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4379 return ; // normal fast-path return 4380 } 4381 4382 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4383 TEVENT (SpinAcquire - ctx) ; 4384 int ctr = 0 ; 4385 int Yields = 0 ; 4386 for (;;) { 4387 while (*adr != 0) { 4388 ++ctr ; 4389 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4390 if (Yields > 5) { 4391 // Consider using a simple NakedSleep() instead. 4392 // Then SpinAcquire could be called by non-JVM threads 4393 Thread::current()->_ParkEvent->park(1) ; 4394 } else { 4395 os::NakedYield() ; 4396 ++Yields ; 4397 } 4398 } else { 4399 SpinPause() ; 4400 } 4401 } 4402 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4403 } 4404} 4405 4406void Thread::SpinRelease (volatile int * adr) { 4407 assert (*adr != 0, "invariant") ; 4408 OrderAccess::fence() ; // guarantee at least release consistency. 4409 // Roach-motel semantics. 4410 // It's safe if subsequent LDs and STs float "up" into the critical section, 4411 // but prior LDs and STs within the critical section can't be allowed 4412 // to reorder or float past the ST that releases the lock. 4413 *adr = 0 ; 4414} 4415 4416// muxAcquire and muxRelease: 4417// 4418// * muxAcquire and muxRelease support a single-word lock-word construct. 4419// The LSB of the word is set IFF the lock is held. 4420// The remainder of the word points to the head of a singly-linked list 4421// of threads blocked on the lock. 4422// 4423// * The current implementation of muxAcquire-muxRelease uses its own 4424// dedicated Thread._MuxEvent instance. If we're interested in 4425// minimizing the peak number of extant ParkEvent instances then 4426// we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4427// as certain invariants were satisfied. Specifically, care would need 4428// to be taken with regards to consuming unpark() "permits". 4429// A safe rule of thumb is that a thread would never call muxAcquire() 4430// if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4431// park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4432// consume an unpark() permit intended for monitorenter, for instance. 4433// One way around this would be to widen the restricted-range semaphore 4434// implemented in park(). Another alternative would be to provide 4435// multiple instances of the PlatformEvent() for each thread. One 4436// instance would be dedicated to muxAcquire-muxRelease, for instance. 4437// 4438// * Usage: 4439// -- Only as leaf locks 4440// -- for short-term locking only as muxAcquire does not perform 4441// thread state transitions. 4442// 4443// Alternatives: 4444// * We could implement muxAcquire and muxRelease with MCS or CLH locks 4445// but with parking or spin-then-park instead of pure spinning. 4446// * Use Taura-Oyama-Yonenzawa locks. 4447// * It's possible to construct a 1-0 lock if we encode the lockword as 4448// (List,LockByte). Acquire will CAS the full lockword while Release 4449// will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4450// acquiring threads use timers (ParkTimed) to detect and recover from 4451// the stranding window. Thread/Node structures must be aligned on 256-byte 4452// boundaries by using placement-new. 4453// * Augment MCS with advisory back-link fields maintained with CAS(). 4454// Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4455// The validity of the backlinks must be ratified before we trust the value. 4456// If the backlinks are invalid the exiting thread must back-track through the 4457// the forward links, which are always trustworthy. 4458// * Add a successor indication. The LockWord is currently encoded as 4459// (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4460// to provide the usual futile-wakeup optimization. 4461// See RTStt for details. 4462// * Consider schedctl.sc_nopreempt to cover the critical section. 4463// 4464 4465 4466typedef volatile intptr_t MutexT ; // Mux Lock-word 4467enum MuxBits { LOCKBIT = 1 } ; 4468 4469void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4470 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4471 if (w == 0) return ; 4472 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4473 return ; 4474 } 4475 4476 TEVENT (muxAcquire - Contention) ; 4477 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4478 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4479 for (;;) { 4480 int its = (os::is_MP() ? 100 : 0) + 1 ; 4481 4482 // Optional spin phase: spin-then-park strategy 4483 while (--its >= 0) { 4484 w = *Lock ; 4485 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4486 return ; 4487 } 4488 } 4489 4490 Self->reset() ; 4491 Self->OnList = intptr_t(Lock) ; 4492 // The following fence() isn't _strictly necessary as the subsequent 4493 // CAS() both serializes execution and ratifies the fetched *Lock value. 4494 OrderAccess::fence(); 4495 for (;;) { 4496 w = *Lock ; 4497 if ((w & LOCKBIT) == 0) { 4498 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4499 Self->OnList = 0 ; // hygiene - allows stronger asserts 4500 return ; 4501 } 4502 continue ; // Interference -- *Lock changed -- Just retry 4503 } 4504 assert (w & LOCKBIT, "invariant") ; 4505 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4506 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4507 } 4508 4509 while (Self->OnList != 0) { 4510 Self->park() ; 4511 } 4512 } 4513} 4514 4515void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4516 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4517 if (w == 0) return ; 4518 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4519 return ; 4520 } 4521 4522 TEVENT (muxAcquire - Contention) ; 4523 ParkEvent * ReleaseAfter = NULL ; 4524 if (ev == NULL) { 4525 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4526 } 4527 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4528 for (;;) { 4529 guarantee (ev->OnList == 0, "invariant") ; 4530 int its = (os::is_MP() ? 100 : 0) + 1 ; 4531 4532 // Optional spin phase: spin-then-park strategy 4533 while (--its >= 0) { 4534 w = *Lock ; 4535 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4536 if (ReleaseAfter != NULL) { 4537 ParkEvent::Release (ReleaseAfter) ; 4538 } 4539 return ; 4540 } 4541 } 4542 4543 ev->reset() ; 4544 ev->OnList = intptr_t(Lock) ; 4545 // The following fence() isn't _strictly necessary as the subsequent 4546 // CAS() both serializes execution and ratifies the fetched *Lock value. 4547 OrderAccess::fence(); 4548 for (;;) { 4549 w = *Lock ; 4550 if ((w & LOCKBIT) == 0) { 4551 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4552 ev->OnList = 0 ; 4553 // We call ::Release while holding the outer lock, thus 4554 // artificially lengthening the critical section. 4555 // Consider deferring the ::Release() until the subsequent unlock(), 4556 // after we've dropped the outer lock. 4557 if (ReleaseAfter != NULL) { 4558 ParkEvent::Release (ReleaseAfter) ; 4559 } 4560 return ; 4561 } 4562 continue ; // Interference -- *Lock changed -- Just retry 4563 } 4564 assert (w & LOCKBIT, "invariant") ; 4565 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4566 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4567 } 4568 4569 while (ev->OnList != 0) { 4570 ev->park() ; 4571 } 4572 } 4573} 4574 4575// Release() must extract a successor from the list and then wake that thread. 4576// It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4577// similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4578// Release() would : 4579// (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4580// (B) Extract a successor from the private list "in-hand" 4581// (C) attempt to CAS() the residual back into *Lock over null. 4582// If there were any newly arrived threads and the CAS() would fail. 4583// In that case Release() would detach the RATs, re-merge the list in-hand 4584// with the RATs and repeat as needed. Alternately, Release() might 4585// detach and extract a successor, but then pass the residual list to the wakee. 4586// The wakee would be responsible for reattaching and remerging before it 4587// competed for the lock. 4588// 4589// Both "pop" and DMR are immune from ABA corruption -- there can be 4590// multiple concurrent pushers, but only one popper or detacher. 4591// This implementation pops from the head of the list. This is unfair, 4592// but tends to provide excellent throughput as hot threads remain hot. 4593// (We wake recently run threads first). 4594 4595void Thread::muxRelease (volatile intptr_t * Lock) { 4596 for (;;) { 4597 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4598 assert (w & LOCKBIT, "invariant") ; 4599 if (w == LOCKBIT) return ; 4600 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4601 assert (List != NULL, "invariant") ; 4602 assert (List->OnList == intptr_t(Lock), "invariant") ; 4603 ParkEvent * nxt = List->ListNext ; 4604 4605 // The following CAS() releases the lock and pops the head element. 4606 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4607 continue ; 4608 } 4609 List->OnList = 0 ; 4610 OrderAccess::fence() ; 4611 List->unpark () ; 4612 return ; 4613 } 4614} 4615 4616 4617void Threads::verify() { 4618 ALL_JAVA_THREADS(p) { 4619 p->verify(); 4620 } 4621 VMThread* thread = VMThread::vm_thread(); 4622 if (thread != NULL) thread->verify(); 4623} 4624