thread.cpp revision 3644:716e6ef4482a
1/* 2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "precompiled.hpp" 26#include "classfile/classLoader.hpp" 27#include "classfile/javaClasses.hpp" 28#include "classfile/systemDictionary.hpp" 29#include "classfile/vmSymbols.hpp" 30#include "code/scopeDesc.hpp" 31#include "compiler/compileBroker.hpp" 32#include "interpreter/interpreter.hpp" 33#include "interpreter/linkResolver.hpp" 34#include "interpreter/oopMapCache.hpp" 35#include "jvmtifiles/jvmtiEnv.hpp" 36#include "memory/gcLocker.inline.hpp" 37#include "memory/metaspaceShared.hpp" 38#include "memory/oopFactory.hpp" 39#include "memory/universe.inline.hpp" 40#include "oops/instanceKlass.hpp" 41#include "oops/objArrayOop.hpp" 42#include "oops/oop.inline.hpp" 43#include "oops/symbol.hpp" 44#include "prims/jvm_misc.hpp" 45#include "prims/jvmtiExport.hpp" 46#include "prims/jvmtiThreadState.hpp" 47#include "prims/privilegedStack.hpp" 48#include "runtime/aprofiler.hpp" 49#include "runtime/arguments.hpp" 50#include "runtime/biasedLocking.hpp" 51#include "runtime/deoptimization.hpp" 52#include "runtime/fprofiler.hpp" 53#include "runtime/frame.inline.hpp" 54#include "runtime/init.hpp" 55#include "runtime/interfaceSupport.hpp" 56#include "runtime/java.hpp" 57#include "runtime/javaCalls.hpp" 58#include "runtime/jniPeriodicChecker.hpp" 59#include "runtime/memprofiler.hpp" 60#include "runtime/mutexLocker.hpp" 61#include "runtime/objectMonitor.hpp" 62#include "runtime/osThread.hpp" 63#include "runtime/safepoint.hpp" 64#include "runtime/sharedRuntime.hpp" 65#include "runtime/statSampler.hpp" 66#include "runtime/stubRoutines.hpp" 67#include "runtime/task.hpp" 68#include "runtime/threadCritical.hpp" 69#include "runtime/threadLocalStorage.hpp" 70#include "runtime/vframe.hpp" 71#include "runtime/vframeArray.hpp" 72#include "runtime/vframe_hp.hpp" 73#include "runtime/vmThread.hpp" 74#include "runtime/vm_operations.hpp" 75#include "services/attachListener.hpp" 76#include "services/management.hpp" 77#include "services/memTracker.hpp" 78#include "services/threadService.hpp" 79#include "trace/traceEventTypes.hpp" 80#include "utilities/defaultStream.hpp" 81#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 st->print("prio=%d tid=" INTPTR_FORMAT " ", get_priority(this), this); 846 osthread()->print_on(st); 847 } 848 debug_only(if (WizardMode) print_owned_locks_on(st);) 849} 850 851// Thread::print_on_error() is called by fatal error handler. Don't use 852// any lock or allocate memory. 853void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 854 if (is_VM_thread()) st->print("VMThread"); 855 else if (is_Compiler_thread()) st->print("CompilerThread"); 856 else if (is_Java_thread()) st->print("JavaThread"); 857 else if (is_GC_task_thread()) st->print("GCTaskThread"); 858 else if (is_Watcher_thread()) st->print("WatcherThread"); 859 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 860 else st->print("Thread"); 861 862 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 863 _stack_base - _stack_size, _stack_base); 864 865 if (osthread()) { 866 st->print(" [id=%d]", osthread()->thread_id()); 867 } 868} 869 870#ifdef ASSERT 871void Thread::print_owned_locks_on(outputStream* st) const { 872 Monitor *cur = _owned_locks; 873 if (cur == NULL) { 874 st->print(" (no locks) "); 875 } else { 876 st->print_cr(" Locks owned:"); 877 while(cur) { 878 cur->print_on(st); 879 cur = cur->next(); 880 } 881 } 882} 883 884static int ref_use_count = 0; 885 886bool Thread::owns_locks_but_compiled_lock() const { 887 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 888 if (cur != Compile_lock) return true; 889 } 890 return false; 891} 892 893 894#endif 895 896#ifndef PRODUCT 897 898// The flag: potential_vm_operation notifies if this particular safepoint state could potential 899// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 900// no threads which allow_vm_block's are held 901void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 902 // Check if current thread is allowed to block at a safepoint 903 if (!(_allow_safepoint_count == 0)) 904 fatal("Possible safepoint reached by thread that does not allow it"); 905 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 906 fatal("LEAF method calling lock?"); 907 } 908 909#ifdef ASSERT 910 if (potential_vm_operation && is_Java_thread() 911 && !Universe::is_bootstrapping()) { 912 // Make sure we do not hold any locks that the VM thread also uses. 913 // This could potentially lead to deadlocks 914 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 915 // Threads_lock is special, since the safepoint synchronization will not start before this is 916 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 917 // since it is used to transfer control between JavaThreads and the VMThread 918 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first! 919 if ( (cur->allow_vm_block() && 920 cur != Threads_lock && 921 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation 922 cur != VMOperationRequest_lock && 923 cur != VMOperationQueue_lock) || 924 cur->rank() == Mutex::special) { 925 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 926 } 927 } 928 } 929 930 if (GCALotAtAllSafepoints) { 931 // We could enter a safepoint here and thus have a gc 932 InterfaceSupport::check_gc_alot(); 933 } 934#endif 935} 936#endif 937 938bool Thread::is_in_stack(address adr) const { 939 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 940 address end = os::current_stack_pointer(); 941 // Allow non Java threads to call this without stack_base 942 if (_stack_base == NULL) return true; 943 if (stack_base() >= adr && adr >= end) return true; 944 945 return false; 946} 947 948 949// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 950// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 951// used for compilation in the future. If that change is made, the need for these methods 952// should be revisited, and they should be removed if possible. 953 954bool Thread::is_lock_owned(address adr) const { 955 return on_local_stack(adr); 956} 957 958bool Thread::set_as_starting_thread() { 959 // NOTE: this must be called inside the main thread. 960 return os::create_main_thread((JavaThread*)this); 961} 962 963static void initialize_class(Symbol* class_name, TRAPS) { 964 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 965 InstanceKlass::cast(klass)->initialize(CHECK); 966} 967 968 969// Creates the initial ThreadGroup 970static Handle create_initial_thread_group(TRAPS) { 971 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 972 instanceKlassHandle klass (THREAD, k); 973 974 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 975 { 976 JavaValue result(T_VOID); 977 JavaCalls::call_special(&result, 978 system_instance, 979 klass, 980 vmSymbols::object_initializer_name(), 981 vmSymbols::void_method_signature(), 982 CHECK_NH); 983 } 984 Universe::set_system_thread_group(system_instance()); 985 986 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 987 { 988 JavaValue result(T_VOID); 989 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 990 JavaCalls::call_special(&result, 991 main_instance, 992 klass, 993 vmSymbols::object_initializer_name(), 994 vmSymbols::threadgroup_string_void_signature(), 995 system_instance, 996 string, 997 CHECK_NH); 998 } 999 return main_instance; 1000} 1001 1002// Creates the initial Thread 1003static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1004 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1005 instanceKlassHandle klass (THREAD, k); 1006 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1007 1008 java_lang_Thread::set_thread(thread_oop(), thread); 1009 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1010 thread->set_threadObj(thread_oop()); 1011 1012 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1013 1014 JavaValue result(T_VOID); 1015 JavaCalls::call_special(&result, thread_oop, 1016 klass, 1017 vmSymbols::object_initializer_name(), 1018 vmSymbols::threadgroup_string_void_signature(), 1019 thread_group, 1020 string, 1021 CHECK_NULL); 1022 return thread_oop(); 1023} 1024 1025static void call_initializeSystemClass(TRAPS) { 1026 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1027 instanceKlassHandle klass (THREAD, k); 1028 1029 JavaValue result(T_VOID); 1030 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1031 vmSymbols::void_method_signature(), CHECK); 1032} 1033 1034char java_runtime_name[128] = ""; 1035 1036// extract the JRE name from sun.misc.Version.java_runtime_name 1037static const char* get_java_runtime_name(TRAPS) { 1038 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1039 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1040 fieldDescriptor fd; 1041 bool found = k != NULL && 1042 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1043 vmSymbols::string_signature(), &fd); 1044 if (found) { 1045 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1046 if (name_oop == NULL) 1047 return NULL; 1048 const char* name = java_lang_String::as_utf8_string(name_oop, 1049 java_runtime_name, 1050 sizeof(java_runtime_name)); 1051 return name; 1052 } else { 1053 return NULL; 1054 } 1055} 1056 1057// General purpose hook into Java code, run once when the VM is initialized. 1058// The Java library method itself may be changed independently from the VM. 1059static void call_postVMInitHook(TRAPS) { 1060 Klass* k = SystemDictionary::PostVMInitHook_klass(); 1061 instanceKlassHandle klass (THREAD, k); 1062 if (klass.not_null()) { 1063 JavaValue result(T_VOID); 1064 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1065 vmSymbols::void_method_signature(), 1066 CHECK); 1067 } 1068} 1069 1070static void reset_vm_info_property(TRAPS) { 1071 // the vm info string 1072 ResourceMark rm(THREAD); 1073 const char *vm_info = VM_Version::vm_info_string(); 1074 1075 // java.lang.System class 1076 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1077 instanceKlassHandle klass (THREAD, k); 1078 1079 // setProperty arguments 1080 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1081 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1082 1083 // return value 1084 JavaValue r(T_OBJECT); 1085 1086 // public static String setProperty(String key, String value); 1087 JavaCalls::call_static(&r, 1088 klass, 1089 vmSymbols::setProperty_name(), 1090 vmSymbols::string_string_string_signature(), 1091 key_str, 1092 value_str, 1093 CHECK); 1094} 1095 1096 1097void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1098 assert(thread_group.not_null(), "thread group should be specified"); 1099 assert(threadObj() == NULL, "should only create Java thread object once"); 1100 1101 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1102 instanceKlassHandle klass (THREAD, k); 1103 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1104 1105 java_lang_Thread::set_thread(thread_oop(), this); 1106 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1107 set_threadObj(thread_oop()); 1108 1109 JavaValue result(T_VOID); 1110 if (thread_name != NULL) { 1111 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1112 // Thread gets assigned specified name and null target 1113 JavaCalls::call_special(&result, 1114 thread_oop, 1115 klass, 1116 vmSymbols::object_initializer_name(), 1117 vmSymbols::threadgroup_string_void_signature(), 1118 thread_group, // Argument 1 1119 name, // Argument 2 1120 THREAD); 1121 } else { 1122 // Thread gets assigned name "Thread-nnn" and null target 1123 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1124 JavaCalls::call_special(&result, 1125 thread_oop, 1126 klass, 1127 vmSymbols::object_initializer_name(), 1128 vmSymbols::threadgroup_runnable_void_signature(), 1129 thread_group, // Argument 1 1130 Handle(), // Argument 2 1131 THREAD); 1132 } 1133 1134 1135 if (daemon) { 1136 java_lang_Thread::set_daemon(thread_oop()); 1137 } 1138 1139 if (HAS_PENDING_EXCEPTION) { 1140 return; 1141 } 1142 1143 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1144 Handle threadObj(this, this->threadObj()); 1145 1146 JavaCalls::call_special(&result, 1147 thread_group, 1148 group, 1149 vmSymbols::add_method_name(), 1150 vmSymbols::thread_void_signature(), 1151 threadObj, // Arg 1 1152 THREAD); 1153 1154 1155} 1156 1157// NamedThread -- non-JavaThread subclasses with multiple 1158// uniquely named instances should derive from this. 1159NamedThread::NamedThread() : Thread() { 1160 _name = NULL; 1161 _processed_thread = NULL; 1162} 1163 1164NamedThread::~NamedThread() { 1165 if (_name != NULL) { 1166 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1167 _name = NULL; 1168 } 1169} 1170 1171void NamedThread::set_name(const char* format, ...) { 1172 guarantee(_name == NULL, "Only get to set name once."); 1173 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1174 guarantee(_name != NULL, "alloc failure"); 1175 va_list ap; 1176 va_start(ap, format); 1177 jio_vsnprintf(_name, max_name_len, format, ap); 1178 va_end(ap); 1179} 1180 1181// ======= WatcherThread ======== 1182 1183// The watcher thread exists to simulate timer interrupts. It should 1184// be replaced by an abstraction over whatever native support for 1185// timer interrupts exists on the platform. 1186 1187WatcherThread* WatcherThread::_watcher_thread = NULL; 1188volatile bool WatcherThread::_should_terminate = false; 1189 1190WatcherThread::WatcherThread() : Thread() { 1191 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1192 if (os::create_thread(this, os::watcher_thread)) { 1193 _watcher_thread = this; 1194 1195 // Set the watcher thread to the highest OS priority which should not be 1196 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1197 // is created. The only normal thread using this priority is the reference 1198 // handler thread, which runs for very short intervals only. 1199 // If the VMThread's priority is not lower than the WatcherThread profiling 1200 // will be inaccurate. 1201 os::set_priority(this, MaxPriority); 1202 if (!DisableStartThread) { 1203 os::start_thread(this); 1204 } 1205 } 1206} 1207 1208void WatcherThread::run() { 1209 assert(this == watcher_thread(), "just checking"); 1210 1211 this->record_stack_base_and_size(); 1212 this->initialize_thread_local_storage(); 1213 this->set_active_handles(JNIHandleBlock::allocate_block()); 1214 while(!_should_terminate) { 1215 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1216 assert(watcher_thread() == this, "thread consistency check"); 1217 1218 // Calculate how long it'll be until the next PeriodicTask work 1219 // should be done, and sleep that amount of time. 1220 size_t time_to_wait = PeriodicTask::time_to_wait(); 1221 1222 // we expect this to timeout - we only ever get unparked when 1223 // we should terminate 1224 { 1225 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1226 1227 jlong prev_time = os::javaTimeNanos(); 1228 for (;;) { 1229 int res= _SleepEvent->park(time_to_wait); 1230 if (res == OS_TIMEOUT || _should_terminate) 1231 break; 1232 // spurious wakeup of some kind 1233 jlong now = os::javaTimeNanos(); 1234 time_to_wait -= (now - prev_time) / 1000000; 1235 if (time_to_wait <= 0) 1236 break; 1237 prev_time = now; 1238 } 1239 } 1240 1241 if (is_error_reported()) { 1242 // A fatal error has happened, the error handler(VMError::report_and_die) 1243 // should abort JVM after creating an error log file. However in some 1244 // rare cases, the error handler itself might deadlock. Here we try to 1245 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1246 // 1247 // This code is in WatcherThread because WatcherThread wakes up 1248 // periodically so the fatal error handler doesn't need to do anything; 1249 // also because the WatcherThread is less likely to crash than other 1250 // threads. 1251 1252 for (;;) { 1253 if (!ShowMessageBoxOnError 1254 && (OnError == NULL || OnError[0] == '\0') 1255 && Arguments::abort_hook() == NULL) { 1256 os::sleep(this, 2 * 60 * 1000, false); 1257 fdStream err(defaultStream::output_fd()); 1258 err.print_raw_cr("# [ timer expired, abort... ]"); 1259 // skip atexit/vm_exit/vm_abort hooks 1260 os::die(); 1261 } 1262 1263 // Wake up 5 seconds later, the fatal handler may reset OnError or 1264 // ShowMessageBoxOnError when it is ready to abort. 1265 os::sleep(this, 5 * 1000, false); 1266 } 1267 } 1268 1269 PeriodicTask::real_time_tick(time_to_wait); 1270 1271 // If we have no more tasks left due to dynamic disenrollment, 1272 // shut down the thread since we don't currently support dynamic enrollment 1273 if (PeriodicTask::num_tasks() == 0) { 1274 _should_terminate = true; 1275 } 1276 } 1277 1278 // Signal that it is terminated 1279 { 1280 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1281 _watcher_thread = NULL; 1282 Terminator_lock->notify(); 1283 } 1284 1285 // Thread destructor usually does this.. 1286 ThreadLocalStorage::set_thread(NULL); 1287} 1288 1289void WatcherThread::start() { 1290 if (watcher_thread() == NULL) { 1291 _should_terminate = false; 1292 // Create the single instance of WatcherThread 1293 new WatcherThread(); 1294 } 1295} 1296 1297void WatcherThread::stop() { 1298 // it is ok to take late safepoints here, if needed 1299 MutexLocker mu(Terminator_lock); 1300 _should_terminate = true; 1301 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1302 1303 Thread* watcher = watcher_thread(); 1304 if (watcher != NULL) 1305 watcher->_SleepEvent->unpark(); 1306 1307 while(watcher_thread() != NULL) { 1308 // This wait should make safepoint checks, wait without a timeout, 1309 // and wait as a suspend-equivalent condition. 1310 // 1311 // Note: If the FlatProfiler is running, then this thread is waiting 1312 // for the WatcherThread to terminate and the WatcherThread, via the 1313 // FlatProfiler task, is waiting for the external suspend request on 1314 // this thread to complete. wait_for_ext_suspend_completion() will 1315 // eventually timeout, but that takes time. Making this wait a 1316 // suspend-equivalent condition solves that timeout problem. 1317 // 1318 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1319 Mutex::_as_suspend_equivalent_flag); 1320 } 1321} 1322 1323void WatcherThread::print_on(outputStream* st) const { 1324 st->print("\"%s\" ", name()); 1325 Thread::print_on(st); 1326 st->cr(); 1327} 1328 1329// ======= JavaThread ======== 1330 1331// A JavaThread is a normal Java thread 1332 1333void JavaThread::initialize() { 1334 // Initialize fields 1335 1336 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1337 set_claimed_par_id(-1); 1338 1339 set_saved_exception_pc(NULL); 1340 set_threadObj(NULL); 1341 _anchor.clear(); 1342 set_entry_point(NULL); 1343 set_jni_functions(jni_functions()); 1344 set_callee_target(NULL); 1345 set_vm_result(NULL); 1346 set_vm_result_2(NULL); 1347 set_vframe_array_head(NULL); 1348 set_vframe_array_last(NULL); 1349 set_deferred_locals(NULL); 1350 set_deopt_mark(NULL); 1351 set_deopt_nmethod(NULL); 1352 clear_must_deopt_id(); 1353 set_monitor_chunks(NULL); 1354 set_next(NULL); 1355 set_thread_state(_thread_new); 1356 set_recorder(NULL); 1357 _terminated = _not_terminated; 1358 _privileged_stack_top = NULL; 1359 _array_for_gc = NULL; 1360 _suspend_equivalent = false; 1361 _in_deopt_handler = 0; 1362 _doing_unsafe_access = false; 1363 _stack_guard_state = stack_guard_unused; 1364 _exception_oop = NULL; 1365 _exception_pc = 0; 1366 _exception_handler_pc = 0; 1367 _is_method_handle_return = 0; 1368 _jvmti_thread_state= NULL; 1369 _should_post_on_exceptions_flag = JNI_FALSE; 1370 _jvmti_get_loaded_classes_closure = NULL; 1371 _interp_only_mode = 0; 1372 _special_runtime_exit_condition = _no_async_condition; 1373 _pending_async_exception = NULL; 1374 _is_compiling = false; 1375 _thread_stat = NULL; 1376 _thread_stat = new ThreadStatistics(); 1377 _blocked_on_compilation = false; 1378 _jni_active_critical = 0; 1379 _do_not_unlock_if_synchronized = false; 1380 _cached_monitor_info = NULL; 1381 _parker = Parker::Allocate(this) ; 1382 1383#ifndef PRODUCT 1384 _jmp_ring_index = 0; 1385 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1386 record_jump(NULL, NULL, NULL, 0); 1387 } 1388#endif /* PRODUCT */ 1389 1390 set_thread_profiler(NULL); 1391 if (FlatProfiler::is_active()) { 1392 // This is where we would decide to either give each thread it's own profiler 1393 // or use one global one from FlatProfiler, 1394 // or up to some count of the number of profiled threads, etc. 1395 ThreadProfiler* pp = new ThreadProfiler(); 1396 pp->engage(); 1397 set_thread_profiler(pp); 1398 } 1399 1400 // Setup safepoint state info for this thread 1401 ThreadSafepointState::create(this); 1402 1403 debug_only(_java_call_counter = 0); 1404 1405 // JVMTI PopFrame support 1406 _popframe_condition = popframe_inactive; 1407 _popframe_preserved_args = NULL; 1408 _popframe_preserved_args_size = 0; 1409 1410 pd_initialize(); 1411} 1412 1413#ifndef SERIALGC 1414SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1415DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1416#endif // !SERIALGC 1417 1418JavaThread::JavaThread(bool is_attaching_via_jni) : 1419 Thread() 1420#ifndef SERIALGC 1421 , _satb_mark_queue(&_satb_mark_queue_set), 1422 _dirty_card_queue(&_dirty_card_queue_set) 1423#endif // !SERIALGC 1424{ 1425 initialize(); 1426 if (is_attaching_via_jni) { 1427 _jni_attach_state = _attaching_via_jni; 1428 } else { 1429 _jni_attach_state = _not_attaching_via_jni; 1430 } 1431 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor"); 1432 _safepoint_visible = false; 1433} 1434 1435bool JavaThread::reguard_stack(address cur_sp) { 1436 if (_stack_guard_state != stack_guard_yellow_disabled) { 1437 return true; // Stack already guarded or guard pages not needed. 1438 } 1439 1440 if (register_stack_overflow()) { 1441 // For those architectures which have separate register and 1442 // memory stacks, we must check the register stack to see if 1443 // it has overflowed. 1444 return false; 1445 } 1446 1447 // Java code never executes within the yellow zone: the latter is only 1448 // there to provoke an exception during stack banging. If java code 1449 // is executing there, either StackShadowPages should be larger, or 1450 // some exception code in c1, c2 or the interpreter isn't unwinding 1451 // when it should. 1452 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1453 1454 enable_stack_yellow_zone(); 1455 return true; 1456} 1457 1458bool JavaThread::reguard_stack(void) { 1459 return reguard_stack(os::current_stack_pointer()); 1460} 1461 1462 1463void JavaThread::block_if_vm_exited() { 1464 if (_terminated == _vm_exited) { 1465 // _vm_exited is set at safepoint, and Threads_lock is never released 1466 // we will block here forever 1467 Threads_lock->lock_without_safepoint_check(); 1468 ShouldNotReachHere(); 1469 } 1470} 1471 1472 1473// Remove this ifdef when C1 is ported to the compiler interface. 1474static void compiler_thread_entry(JavaThread* thread, TRAPS); 1475 1476JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1477 Thread() 1478#ifndef SERIALGC 1479 , _satb_mark_queue(&_satb_mark_queue_set), 1480 _dirty_card_queue(&_dirty_card_queue_set) 1481#endif // !SERIALGC 1482{ 1483 if (TraceThreadEvents) { 1484 tty->print_cr("creating thread %p", this); 1485 } 1486 initialize(); 1487 _jni_attach_state = _not_attaching_via_jni; 1488 set_entry_point(entry_point); 1489 // Create the native thread itself. 1490 // %note runtime_23 1491 os::ThreadType thr_type = os::java_thread; 1492 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1493 os::java_thread; 1494 os::create_thread(this, thr_type, stack_sz); 1495 _safepoint_visible = false; 1496 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1497 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1498 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1499 // the exception consists of creating the exception object & initializing it, initialization 1500 // will leave the VM via a JavaCall and then all locks must be unlocked). 1501 // 1502 // The thread is still suspended when we reach here. Thread must be explicit started 1503 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1504 // by calling Threads:add. The reason why this is not done here, is because the thread 1505 // object must be fully initialized (take a look at JVM_Start) 1506} 1507 1508JavaThread::~JavaThread() { 1509 if (TraceThreadEvents) { 1510 tty->print_cr("terminate thread %p", this); 1511 } 1512 1513 // Info NMT that this JavaThread is exiting, its memory 1514 // recorder should be collected 1515 assert(!is_safepoint_visible(), "wrong state"); 1516 MemTracker::thread_exiting(this); 1517 1518 // JSR166 -- return the parker to the free list 1519 Parker::Release(_parker); 1520 _parker = NULL ; 1521 1522 // Free any remaining previous UnrollBlock 1523 vframeArray* old_array = vframe_array_last(); 1524 1525 if (old_array != NULL) { 1526 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1527 old_array->set_unroll_block(NULL); 1528 delete old_info; 1529 delete old_array; 1530 } 1531 1532 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1533 if (deferred != NULL) { 1534 // This can only happen if thread is destroyed before deoptimization occurs. 1535 assert(deferred->length() != 0, "empty array!"); 1536 do { 1537 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1538 deferred->remove_at(0); 1539 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1540 delete dlv; 1541 } while (deferred->length() != 0); 1542 delete deferred; 1543 } 1544 1545 // All Java related clean up happens in exit 1546 ThreadSafepointState::destroy(this); 1547 if (_thread_profiler != NULL) delete _thread_profiler; 1548 if (_thread_stat != NULL) delete _thread_stat; 1549} 1550 1551 1552// The first routine called by a new Java thread 1553void JavaThread::run() { 1554 // initialize thread-local alloc buffer related fields 1555 this->initialize_tlab(); 1556 1557 // used to test validitity of stack trace backs 1558 this->record_base_of_stack_pointer(); 1559 1560 // Record real stack base and size. 1561 this->record_stack_base_and_size(); 1562 1563 // Initialize thread local storage; set before calling MutexLocker 1564 this->initialize_thread_local_storage(); 1565 1566 this->create_stack_guard_pages(); 1567 1568 this->cache_global_variables(); 1569 1570 // Thread is now sufficient initialized to be handled by the safepoint code as being 1571 // in the VM. Change thread state from _thread_new to _thread_in_vm 1572 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1573 1574 assert(JavaThread::current() == this, "sanity check"); 1575 assert(!Thread::current()->owns_locks(), "sanity check"); 1576 1577 DTRACE_THREAD_PROBE(start, this); 1578 1579 // This operation might block. We call that after all safepoint checks for a new thread has 1580 // been completed. 1581 this->set_active_handles(JNIHandleBlock::allocate_block()); 1582 1583 if (JvmtiExport::should_post_thread_life()) { 1584 JvmtiExport::post_thread_start(this); 1585 } 1586 1587 EVENT_BEGIN(TraceEventThreadStart, event); 1588 EVENT_COMMIT(event, 1589 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj()))); 1590 1591 // We call another function to do the rest so we are sure that the stack addresses used 1592 // from there will be lower than the stack base just computed 1593 thread_main_inner(); 1594 1595 // Note, thread is no longer valid at this point! 1596} 1597 1598 1599void JavaThread::thread_main_inner() { 1600 assert(JavaThread::current() == this, "sanity check"); 1601 assert(this->threadObj() != NULL, "just checking"); 1602 1603 // Execute thread entry point unless this thread has a pending exception 1604 // or has been stopped before starting. 1605 // Note: Due to JVM_StopThread we can have pending exceptions already! 1606 if (!this->has_pending_exception() && 1607 !java_lang_Thread::is_stillborn(this->threadObj())) { 1608 { 1609 ResourceMark rm(this); 1610 this->set_native_thread_name(this->get_thread_name()); 1611 } 1612 HandleMark hm(this); 1613 this->entry_point()(this, this); 1614 } 1615 1616 DTRACE_THREAD_PROBE(stop, this); 1617 1618 this->exit(false); 1619 delete this; 1620} 1621 1622 1623static void ensure_join(JavaThread* thread) { 1624 // We do not need to grap the Threads_lock, since we are operating on ourself. 1625 Handle threadObj(thread, thread->threadObj()); 1626 assert(threadObj.not_null(), "java thread object must exist"); 1627 ObjectLocker lock(threadObj, thread); 1628 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1629 thread->clear_pending_exception(); 1630 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1631 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1632 // Clear the native thread instance - this makes isAlive return false and allows the join() 1633 // to complete once we've done the notify_all below 1634 java_lang_Thread::set_thread(threadObj(), NULL); 1635 lock.notify_all(thread); 1636 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1637 thread->clear_pending_exception(); 1638} 1639 1640 1641// For any new cleanup additions, please check to see if they need to be applied to 1642// cleanup_failed_attach_current_thread as well. 1643void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1644 assert(this == JavaThread::current(), "thread consistency check"); 1645 if (!InitializeJavaLangSystem) return; 1646 1647 HandleMark hm(this); 1648 Handle uncaught_exception(this, this->pending_exception()); 1649 this->clear_pending_exception(); 1650 Handle threadObj(this, this->threadObj()); 1651 assert(threadObj.not_null(), "Java thread object should be created"); 1652 1653 if (get_thread_profiler() != NULL) { 1654 get_thread_profiler()->disengage(); 1655 ResourceMark rm; 1656 get_thread_profiler()->print(get_thread_name()); 1657 } 1658 1659 1660 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1661 { 1662 EXCEPTION_MARK; 1663 1664 CLEAR_PENDING_EXCEPTION; 1665 } 1666 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1667 // has to be fixed by a runtime query method 1668 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1669 // JSR-166: change call from from ThreadGroup.uncaughtException to 1670 // java.lang.Thread.dispatchUncaughtException 1671 if (uncaught_exception.not_null()) { 1672 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1673 { 1674 EXCEPTION_MARK; 1675 // Check if the method Thread.dispatchUncaughtException() exists. If so 1676 // call it. Otherwise we have an older library without the JSR-166 changes, 1677 // so call ThreadGroup.uncaughtException() 1678 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1679 CallInfo callinfo; 1680 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1681 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1682 vmSymbols::dispatchUncaughtException_name(), 1683 vmSymbols::throwable_void_signature(), 1684 KlassHandle(), false, false, THREAD); 1685 CLEAR_PENDING_EXCEPTION; 1686 methodHandle method = callinfo.selected_method(); 1687 if (method.not_null()) { 1688 JavaValue result(T_VOID); 1689 JavaCalls::call_virtual(&result, 1690 threadObj, thread_klass, 1691 vmSymbols::dispatchUncaughtException_name(), 1692 vmSymbols::throwable_void_signature(), 1693 uncaught_exception, 1694 THREAD); 1695 } else { 1696 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1697 JavaValue result(T_VOID); 1698 JavaCalls::call_virtual(&result, 1699 group, thread_group, 1700 vmSymbols::uncaughtException_name(), 1701 vmSymbols::thread_throwable_void_signature(), 1702 threadObj, // Arg 1 1703 uncaught_exception, // Arg 2 1704 THREAD); 1705 } 1706 if (HAS_PENDING_EXCEPTION) { 1707 ResourceMark rm(this); 1708 jio_fprintf(defaultStream::error_stream(), 1709 "\nException: %s thrown from the UncaughtExceptionHandler" 1710 " in thread \"%s\"\n", 1711 Klass::cast(pending_exception()->klass())->external_name(), 1712 get_thread_name()); 1713 CLEAR_PENDING_EXCEPTION; 1714 } 1715 } 1716 } 1717 1718 // Called before the java thread exit since we want to read info 1719 // from java_lang_Thread object 1720 EVENT_BEGIN(TraceEventThreadEnd, event); 1721 EVENT_COMMIT(event, 1722 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj()))); 1723 1724 // Call after last event on thread 1725 EVENT_THREAD_EXIT(this); 1726 1727 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1728 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1729 // is deprecated anyhow. 1730 { int count = 3; 1731 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1732 EXCEPTION_MARK; 1733 JavaValue result(T_VOID); 1734 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1735 JavaCalls::call_virtual(&result, 1736 threadObj, thread_klass, 1737 vmSymbols::exit_method_name(), 1738 vmSymbols::void_method_signature(), 1739 THREAD); 1740 CLEAR_PENDING_EXCEPTION; 1741 } 1742 } 1743 1744 // notify JVMTI 1745 if (JvmtiExport::should_post_thread_life()) { 1746 JvmtiExport::post_thread_end(this); 1747 } 1748 1749 // We have notified the agents that we are exiting, before we go on, 1750 // we must check for a pending external suspend request and honor it 1751 // in order to not surprise the thread that made the suspend request. 1752 while (true) { 1753 { 1754 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1755 if (!is_external_suspend()) { 1756 set_terminated(_thread_exiting); 1757 ThreadService::current_thread_exiting(this); 1758 break; 1759 } 1760 // Implied else: 1761 // Things get a little tricky here. We have a pending external 1762 // suspend request, but we are holding the SR_lock so we 1763 // can't just self-suspend. So we temporarily drop the lock 1764 // and then self-suspend. 1765 } 1766 1767 ThreadBlockInVM tbivm(this); 1768 java_suspend_self(); 1769 1770 // We're done with this suspend request, but we have to loop around 1771 // and check again. Eventually we will get SR_lock without a pending 1772 // external suspend request and will be able to mark ourselves as 1773 // exiting. 1774 } 1775 // no more external suspends are allowed at this point 1776 } else { 1777 // before_exit() has already posted JVMTI THREAD_END events 1778 } 1779 1780 // Notify waiters on thread object. This has to be done after exit() is called 1781 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1782 // group should have the destroyed bit set before waiters are notified). 1783 ensure_join(this); 1784 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1785 1786 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1787 // held by this thread must be released. A detach operation must only 1788 // get here if there are no Java frames on the stack. Therefore, any 1789 // owned monitors at this point MUST be JNI-acquired monitors which are 1790 // pre-inflated and in the monitor cache. 1791 // 1792 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1793 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1794 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1795 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1796 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1797 } 1798 1799 // These things needs to be done while we are still a Java Thread. Make sure that thread 1800 // is in a consistent state, in case GC happens 1801 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1802 1803 if (active_handles() != NULL) { 1804 JNIHandleBlock* block = active_handles(); 1805 set_active_handles(NULL); 1806 JNIHandleBlock::release_block(block); 1807 } 1808 1809 if (free_handle_block() != NULL) { 1810 JNIHandleBlock* block = free_handle_block(); 1811 set_free_handle_block(NULL); 1812 JNIHandleBlock::release_block(block); 1813 } 1814 1815 // These have to be removed while this is still a valid thread. 1816 remove_stack_guard_pages(); 1817 1818 if (UseTLAB) { 1819 tlab().make_parsable(true); // retire TLAB 1820 } 1821 1822 if (JvmtiEnv::environments_might_exist()) { 1823 JvmtiExport::cleanup_thread(this); 1824 } 1825 1826#ifndef SERIALGC 1827 // We must flush G1-related buffers before removing a thread from 1828 // the list of active threads. 1829 if (UseG1GC) { 1830 flush_barrier_queues(); 1831 } 1832#endif 1833 1834 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1835 Threads::remove(this); 1836} 1837 1838#ifndef SERIALGC 1839// Flush G1-related queues. 1840void JavaThread::flush_barrier_queues() { 1841 satb_mark_queue().flush(); 1842 dirty_card_queue().flush(); 1843} 1844 1845void JavaThread::initialize_queues() { 1846 assert(!SafepointSynchronize::is_at_safepoint(), 1847 "we should not be at a safepoint"); 1848 1849 ObjPtrQueue& satb_queue = satb_mark_queue(); 1850 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1851 // The SATB queue should have been constructed with its active 1852 // field set to false. 1853 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1854 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1855 // If we are creating the thread during a marking cycle, we should 1856 // set the active field of the SATB queue to true. 1857 if (satb_queue_set.is_active()) { 1858 satb_queue.set_active(true); 1859 } 1860 1861 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1862 // The dirty card queue should have been constructed with its 1863 // active field set to true. 1864 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1865} 1866#endif // !SERIALGC 1867 1868void JavaThread::cleanup_failed_attach_current_thread() { 1869 if (get_thread_profiler() != NULL) { 1870 get_thread_profiler()->disengage(); 1871 ResourceMark rm; 1872 get_thread_profiler()->print(get_thread_name()); 1873 } 1874 1875 if (active_handles() != NULL) { 1876 JNIHandleBlock* block = active_handles(); 1877 set_active_handles(NULL); 1878 JNIHandleBlock::release_block(block); 1879 } 1880 1881 if (free_handle_block() != NULL) { 1882 JNIHandleBlock* block = free_handle_block(); 1883 set_free_handle_block(NULL); 1884 JNIHandleBlock::release_block(block); 1885 } 1886 1887 // These have to be removed while this is still a valid thread. 1888 remove_stack_guard_pages(); 1889 1890 if (UseTLAB) { 1891 tlab().make_parsable(true); // retire TLAB, if any 1892 } 1893 1894#ifndef SERIALGC 1895 if (UseG1GC) { 1896 flush_barrier_queues(); 1897 } 1898#endif 1899 1900 Threads::remove(this); 1901 delete this; 1902} 1903 1904 1905 1906 1907JavaThread* JavaThread::active() { 1908 Thread* thread = ThreadLocalStorage::thread(); 1909 assert(thread != NULL, "just checking"); 1910 if (thread->is_Java_thread()) { 1911 return (JavaThread*) thread; 1912 } else { 1913 assert(thread->is_VM_thread(), "this must be a vm thread"); 1914 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1915 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1916 assert(ret->is_Java_thread(), "must be a Java thread"); 1917 return ret; 1918 } 1919} 1920 1921bool JavaThread::is_lock_owned(address adr) const { 1922 if (Thread::is_lock_owned(adr)) return true; 1923 1924 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1925 if (chunk->contains(adr)) return true; 1926 } 1927 1928 return false; 1929} 1930 1931 1932void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 1933 chunk->set_next(monitor_chunks()); 1934 set_monitor_chunks(chunk); 1935} 1936 1937void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 1938 guarantee(monitor_chunks() != NULL, "must be non empty"); 1939 if (monitor_chunks() == chunk) { 1940 set_monitor_chunks(chunk->next()); 1941 } else { 1942 MonitorChunk* prev = monitor_chunks(); 1943 while (prev->next() != chunk) prev = prev->next(); 1944 prev->set_next(chunk->next()); 1945 } 1946} 1947 1948// JVM support. 1949 1950// Note: this function shouldn't block if it's called in 1951// _thread_in_native_trans state (such as from 1952// check_special_condition_for_native_trans()). 1953void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 1954 1955 if (has_last_Java_frame() && has_async_condition()) { 1956 // If we are at a polling page safepoint (not a poll return) 1957 // then we must defer async exception because live registers 1958 // will be clobbered by the exception path. Poll return is 1959 // ok because the call we a returning from already collides 1960 // with exception handling registers and so there is no issue. 1961 // (The exception handling path kills call result registers but 1962 // this is ok since the exception kills the result anyway). 1963 1964 if (is_at_poll_safepoint()) { 1965 // if the code we are returning to has deoptimized we must defer 1966 // the exception otherwise live registers get clobbered on the 1967 // exception path before deoptimization is able to retrieve them. 1968 // 1969 RegisterMap map(this, false); 1970 frame caller_fr = last_frame().sender(&map); 1971 assert(caller_fr.is_compiled_frame(), "what?"); 1972 if (caller_fr.is_deoptimized_frame()) { 1973 if (TraceExceptions) { 1974 ResourceMark rm; 1975 tty->print_cr("deferred async exception at compiled safepoint"); 1976 } 1977 return; 1978 } 1979 } 1980 } 1981 1982 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 1983 if (condition == _no_async_condition) { 1984 // Conditions have changed since has_special_runtime_exit_condition() 1985 // was called: 1986 // - if we were here only because of an external suspend request, 1987 // then that was taken care of above (or cancelled) so we are done 1988 // - if we were here because of another async request, then it has 1989 // been cleared between the has_special_runtime_exit_condition() 1990 // and now so again we are done 1991 return; 1992 } 1993 1994 // Check for pending async. exception 1995 if (_pending_async_exception != NULL) { 1996 // Only overwrite an already pending exception, if it is not a threadDeath. 1997 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 1998 1999 // We cannot call Exceptions::_throw(...) here because we cannot block 2000 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2001 2002 if (TraceExceptions) { 2003 ResourceMark rm; 2004 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2005 if (has_last_Java_frame() ) { 2006 frame f = last_frame(); 2007 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2008 } 2009 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2010 } 2011 _pending_async_exception = NULL; 2012 clear_has_async_exception(); 2013 } 2014 } 2015 2016 if (check_unsafe_error && 2017 condition == _async_unsafe_access_error && !has_pending_exception()) { 2018 condition = _no_async_condition; // done 2019 switch (thread_state()) { 2020 case _thread_in_vm: 2021 { 2022 JavaThread* THREAD = this; 2023 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2024 } 2025 case _thread_in_native: 2026 { 2027 ThreadInVMfromNative tiv(this); 2028 JavaThread* THREAD = this; 2029 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2030 } 2031 case _thread_in_Java: 2032 { 2033 ThreadInVMfromJava tiv(this); 2034 JavaThread* THREAD = this; 2035 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2036 } 2037 default: 2038 ShouldNotReachHere(); 2039 } 2040 } 2041 2042 assert(condition == _no_async_condition || has_pending_exception() || 2043 (!check_unsafe_error && condition == _async_unsafe_access_error), 2044 "must have handled the async condition, if no exception"); 2045} 2046 2047void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2048 // 2049 // Check for pending external suspend. Internal suspend requests do 2050 // not use handle_special_runtime_exit_condition(). 2051 // If JNIEnv proxies are allowed, don't self-suspend if the target 2052 // thread is not the current thread. In older versions of jdbx, jdbx 2053 // threads could call into the VM with another thread's JNIEnv so we 2054 // can be here operating on behalf of a suspended thread (4432884). 2055 bool do_self_suspend = is_external_suspend_with_lock(); 2056 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2057 // 2058 // Because thread is external suspended the safepoint code will count 2059 // thread as at a safepoint. This can be odd because we can be here 2060 // as _thread_in_Java which would normally transition to _thread_blocked 2061 // at a safepoint. We would like to mark the thread as _thread_blocked 2062 // before calling java_suspend_self like all other callers of it but 2063 // we must then observe proper safepoint protocol. (We can't leave 2064 // _thread_blocked with a safepoint in progress). However we can be 2065 // here as _thread_in_native_trans so we can't use a normal transition 2066 // constructor/destructor pair because they assert on that type of 2067 // transition. We could do something like: 2068 // 2069 // JavaThreadState state = thread_state(); 2070 // set_thread_state(_thread_in_vm); 2071 // { 2072 // ThreadBlockInVM tbivm(this); 2073 // java_suspend_self() 2074 // } 2075 // set_thread_state(_thread_in_vm_trans); 2076 // if (safepoint) block; 2077 // set_thread_state(state); 2078 // 2079 // but that is pretty messy. Instead we just go with the way the 2080 // code has worked before and note that this is the only path to 2081 // java_suspend_self that doesn't put the thread in _thread_blocked 2082 // mode. 2083 2084 frame_anchor()->make_walkable(this); 2085 java_suspend_self(); 2086 2087 // We might be here for reasons in addition to the self-suspend request 2088 // so check for other async requests. 2089 } 2090 2091 if (check_asyncs) { 2092 check_and_handle_async_exceptions(); 2093 } 2094} 2095 2096void JavaThread::send_thread_stop(oop java_throwable) { 2097 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2098 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2099 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2100 2101 // Do not throw asynchronous exceptions against the compiler thread 2102 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2103 if (is_Compiler_thread()) return; 2104 2105 { 2106 // Actually throw the Throwable against the target Thread - however 2107 // only if there is no thread death exception installed already. 2108 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2109 // If the topmost frame is a runtime stub, then we are calling into 2110 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2111 // must deoptimize the caller before continuing, as the compiled exception handler table 2112 // may not be valid 2113 if (has_last_Java_frame()) { 2114 frame f = last_frame(); 2115 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2116 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2117 RegisterMap reg_map(this, UseBiasedLocking); 2118 frame compiled_frame = f.sender(®_map); 2119 if (compiled_frame.can_be_deoptimized()) { 2120 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2121 } 2122 } 2123 } 2124 2125 // Set async. pending exception in thread. 2126 set_pending_async_exception(java_throwable); 2127 2128 if (TraceExceptions) { 2129 ResourceMark rm; 2130 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2131 } 2132 // for AbortVMOnException flag 2133 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2134 } 2135 } 2136 2137 2138 // Interrupt thread so it will wake up from a potential wait() 2139 Thread::interrupt(this); 2140} 2141 2142// External suspension mechanism. 2143// 2144// Tell the VM to suspend a thread when ever it knows that it does not hold on 2145// to any VM_locks and it is at a transition 2146// Self-suspension will happen on the transition out of the vm. 2147// Catch "this" coming in from JNIEnv pointers when the thread has been freed 2148// 2149// Guarantees on return: 2150// + Target thread will not execute any new bytecode (that's why we need to 2151// force a safepoint) 2152// + Target thread will not enter any new monitors 2153// 2154void JavaThread::java_suspend() { 2155 { MutexLocker mu(Threads_lock); 2156 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2157 return; 2158 } 2159 } 2160 2161 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2162 if (!is_external_suspend()) { 2163 // a racing resume has cancelled us; bail out now 2164 return; 2165 } 2166 2167 // suspend is done 2168 uint32_t debug_bits = 0; 2169 // Warning: is_ext_suspend_completed() may temporarily drop the 2170 // SR_lock to allow the thread to reach a stable thread state if 2171 // it is currently in a transient thread state. 2172 if (is_ext_suspend_completed(false /* !called_by_wait */, 2173 SuspendRetryDelay, &debug_bits) ) { 2174 return; 2175 } 2176 } 2177 2178 VM_ForceSafepoint vm_suspend; 2179 VMThread::execute(&vm_suspend); 2180} 2181 2182// Part II of external suspension. 2183// A JavaThread self suspends when it detects a pending external suspend 2184// request. This is usually on transitions. It is also done in places 2185// where continuing to the next transition would surprise the caller, 2186// e.g., monitor entry. 2187// 2188// Returns the number of times that the thread self-suspended. 2189// 2190// Note: DO NOT call java_suspend_self() when you just want to block current 2191// thread. java_suspend_self() is the second stage of cooperative 2192// suspension for external suspend requests and should only be used 2193// to complete an external suspend request. 2194// 2195int JavaThread::java_suspend_self() { 2196 int ret = 0; 2197 2198 // we are in the process of exiting so don't suspend 2199 if (is_exiting()) { 2200 clear_external_suspend(); 2201 return ret; 2202 } 2203 2204 assert(_anchor.walkable() || 2205 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2206 "must have walkable stack"); 2207 2208 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2209 2210 assert(!this->is_ext_suspended(), 2211 "a thread trying to self-suspend should not already be suspended"); 2212 2213 if (this->is_suspend_equivalent()) { 2214 // If we are self-suspending as a result of the lifting of a 2215 // suspend equivalent condition, then the suspend_equivalent 2216 // flag is not cleared until we set the ext_suspended flag so 2217 // that wait_for_ext_suspend_completion() returns consistent 2218 // results. 2219 this->clear_suspend_equivalent(); 2220 } 2221 2222 // A racing resume may have cancelled us before we grabbed SR_lock 2223 // above. Or another external suspend request could be waiting for us 2224 // by the time we return from SR_lock()->wait(). The thread 2225 // that requested the suspension may already be trying to walk our 2226 // stack and if we return now, we can change the stack out from under 2227 // it. This would be a "bad thing (TM)" and cause the stack walker 2228 // to crash. We stay self-suspended until there are no more pending 2229 // external suspend requests. 2230 while (is_external_suspend()) { 2231 ret++; 2232 this->set_ext_suspended(); 2233 2234 // _ext_suspended flag is cleared by java_resume() 2235 while (is_ext_suspended()) { 2236 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2237 } 2238 } 2239 2240 return ret; 2241} 2242 2243#ifdef ASSERT 2244// verify the JavaThread has not yet been published in the Threads::list, and 2245// hence doesn't need protection from concurrent access at this stage 2246void JavaThread::verify_not_published() { 2247 if (!Threads_lock->owned_by_self()) { 2248 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2249 assert( !Threads::includes(this), 2250 "java thread shouldn't have been published yet!"); 2251 } 2252 else { 2253 assert( !Threads::includes(this), 2254 "java thread shouldn't have been published yet!"); 2255 } 2256} 2257#endif 2258 2259// Slow path when the native==>VM/Java barriers detect a safepoint is in 2260// progress or when _suspend_flags is non-zero. 2261// Current thread needs to self-suspend if there is a suspend request and/or 2262// block if a safepoint is in progress. 2263// Async exception ISN'T checked. 2264// Note only the ThreadInVMfromNative transition can call this function 2265// directly and when thread state is _thread_in_native_trans 2266void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2267 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2268 2269 JavaThread *curJT = JavaThread::current(); 2270 bool do_self_suspend = thread->is_external_suspend(); 2271 2272 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2273 2274 // If JNIEnv proxies are allowed, don't self-suspend if the target 2275 // thread is not the current thread. In older versions of jdbx, jdbx 2276 // threads could call into the VM with another thread's JNIEnv so we 2277 // can be here operating on behalf of a suspended thread (4432884). 2278 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2279 JavaThreadState state = thread->thread_state(); 2280 2281 // We mark this thread_blocked state as a suspend-equivalent so 2282 // that a caller to is_ext_suspend_completed() won't be confused. 2283 // The suspend-equivalent state is cleared by java_suspend_self(). 2284 thread->set_suspend_equivalent(); 2285 2286 // If the safepoint code sees the _thread_in_native_trans state, it will 2287 // wait until the thread changes to other thread state. There is no 2288 // guarantee on how soon we can obtain the SR_lock and complete the 2289 // self-suspend request. It would be a bad idea to let safepoint wait for 2290 // too long. Temporarily change the state to _thread_blocked to 2291 // let the VM thread know that this thread is ready for GC. The problem 2292 // of changing thread state is that safepoint could happen just after 2293 // java_suspend_self() returns after being resumed, and VM thread will 2294 // see the _thread_blocked state. We must check for safepoint 2295 // after restoring the state and make sure we won't leave while a safepoint 2296 // is in progress. 2297 thread->set_thread_state(_thread_blocked); 2298 thread->java_suspend_self(); 2299 thread->set_thread_state(state); 2300 // Make sure new state is seen by VM thread 2301 if (os::is_MP()) { 2302 if (UseMembar) { 2303 // Force a fence between the write above and read below 2304 OrderAccess::fence(); 2305 } else { 2306 // Must use this rather than serialization page in particular on Windows 2307 InterfaceSupport::serialize_memory(thread); 2308 } 2309 } 2310 } 2311 2312 if (SafepointSynchronize::do_call_back()) { 2313 // If we are safepointing, then block the caller which may not be 2314 // the same as the target thread (see above). 2315 SafepointSynchronize::block(curJT); 2316 } 2317 2318 if (thread->is_deopt_suspend()) { 2319 thread->clear_deopt_suspend(); 2320 RegisterMap map(thread, false); 2321 frame f = thread->last_frame(); 2322 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2323 f = f.sender(&map); 2324 } 2325 if (f.id() == thread->must_deopt_id()) { 2326 thread->clear_must_deopt_id(); 2327 f.deoptimize(thread); 2328 } else { 2329 fatal("missed deoptimization!"); 2330 } 2331 } 2332} 2333 2334// Slow path when the native==>VM/Java barriers detect a safepoint is in 2335// progress or when _suspend_flags is non-zero. 2336// Current thread needs to self-suspend if there is a suspend request and/or 2337// block if a safepoint is in progress. 2338// Also check for pending async exception (not including unsafe access error). 2339// Note only the native==>VM/Java barriers can call this function and when 2340// thread state is _thread_in_native_trans. 2341void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2342 check_safepoint_and_suspend_for_native_trans(thread); 2343 2344 if (thread->has_async_exception()) { 2345 // We are in _thread_in_native_trans state, don't handle unsafe 2346 // access error since that may block. 2347 thread->check_and_handle_async_exceptions(false); 2348 } 2349} 2350 2351// This is a variant of the normal 2352// check_special_condition_for_native_trans with slightly different 2353// semantics for use by critical native wrappers. It does all the 2354// normal checks but also performs the transition back into 2355// thread_in_Java state. This is required so that critical natives 2356// can potentially block and perform a GC if they are the last thread 2357// exiting the GC_locker. 2358void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2359 check_special_condition_for_native_trans(thread); 2360 2361 // Finish the transition 2362 thread->set_thread_state(_thread_in_Java); 2363 2364 if (thread->do_critical_native_unlock()) { 2365 ThreadInVMfromJavaNoAsyncException tiv(thread); 2366 GC_locker::unlock_critical(thread); 2367 thread->clear_critical_native_unlock(); 2368 } 2369} 2370 2371// We need to guarantee the Threads_lock here, since resumes are not 2372// allowed during safepoint synchronization 2373// Can only resume from an external suspension 2374void JavaThread::java_resume() { 2375 assert_locked_or_safepoint(Threads_lock); 2376 2377 // Sanity check: thread is gone, has started exiting or the thread 2378 // was not externally suspended. 2379 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2380 return; 2381 } 2382 2383 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2384 2385 clear_external_suspend(); 2386 2387 if (is_ext_suspended()) { 2388 clear_ext_suspended(); 2389 SR_lock()->notify_all(); 2390 } 2391} 2392 2393void JavaThread::create_stack_guard_pages() { 2394 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2395 address low_addr = stack_base() - stack_size(); 2396 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2397 2398 int allocate = os::allocate_stack_guard_pages(); 2399 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2400 2401 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2402 warning("Attempt to allocate stack guard pages failed."); 2403 return; 2404 } 2405 2406 if (os::guard_memory((char *) low_addr, len)) { 2407 _stack_guard_state = stack_guard_enabled; 2408 } else { 2409 warning("Attempt to protect stack guard pages failed."); 2410 if (os::uncommit_memory((char *) low_addr, len)) { 2411 warning("Attempt to deallocate stack guard pages failed."); 2412 } 2413 } 2414} 2415 2416void JavaThread::remove_stack_guard_pages() { 2417 if (_stack_guard_state == stack_guard_unused) return; 2418 address low_addr = stack_base() - stack_size(); 2419 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2420 2421 if (os::allocate_stack_guard_pages()) { 2422 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2423 _stack_guard_state = stack_guard_unused; 2424 } else { 2425 warning("Attempt to deallocate stack guard pages failed."); 2426 } 2427 } else { 2428 if (_stack_guard_state == stack_guard_unused) return; 2429 if (os::unguard_memory((char *) low_addr, len)) { 2430 _stack_guard_state = stack_guard_unused; 2431 } else { 2432 warning("Attempt to unprotect stack guard pages failed."); 2433 } 2434 } 2435} 2436 2437void JavaThread::enable_stack_yellow_zone() { 2438 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2439 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2440 2441 // The base notation is from the stacks point of view, growing downward. 2442 // We need to adjust it to work correctly with guard_memory() 2443 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2444 2445 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2446 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2447 2448 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2449 _stack_guard_state = stack_guard_enabled; 2450 } else { 2451 warning("Attempt to guard stack yellow zone failed."); 2452 } 2453 enable_register_stack_guard(); 2454} 2455 2456void JavaThread::disable_stack_yellow_zone() { 2457 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2458 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2459 2460 // Simply return if called for a thread that does not use guard pages. 2461 if (_stack_guard_state == stack_guard_unused) return; 2462 2463 // The base notation is from the stacks point of view, growing downward. 2464 // We need to adjust it to work correctly with guard_memory() 2465 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2466 2467 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2468 _stack_guard_state = stack_guard_yellow_disabled; 2469 } else { 2470 warning("Attempt to unguard stack yellow zone failed."); 2471 } 2472 disable_register_stack_guard(); 2473} 2474 2475void JavaThread::enable_stack_red_zone() { 2476 // The base notation is from the stacks point of view, growing downward. 2477 // We need to adjust it to work correctly with guard_memory() 2478 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2479 address base = stack_red_zone_base() - stack_red_zone_size(); 2480 2481 guarantee(base < stack_base(),"Error calculating stack red zone"); 2482 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2483 2484 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2485 warning("Attempt to guard stack red zone failed."); 2486 } 2487} 2488 2489void JavaThread::disable_stack_red_zone() { 2490 // The base notation is from the stacks point of view, growing downward. 2491 // We need to adjust it to work correctly with guard_memory() 2492 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2493 address base = stack_red_zone_base() - stack_red_zone_size(); 2494 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2495 warning("Attempt to unguard stack red zone failed."); 2496 } 2497} 2498 2499void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2500 // ignore is there is no stack 2501 if (!has_last_Java_frame()) return; 2502 // traverse the stack frames. Starts from top frame. 2503 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2504 frame* fr = fst.current(); 2505 f(fr, fst.register_map()); 2506 } 2507} 2508 2509 2510#ifndef PRODUCT 2511// Deoptimization 2512// Function for testing deoptimization 2513void JavaThread::deoptimize() { 2514 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2515 StackFrameStream fst(this, UseBiasedLocking); 2516 bool deopt = false; // Dump stack only if a deopt actually happens. 2517 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2518 // Iterate over all frames in the thread and deoptimize 2519 for(; !fst.is_done(); fst.next()) { 2520 if(fst.current()->can_be_deoptimized()) { 2521 2522 if (only_at) { 2523 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2524 // consists of comma or carriage return separated numbers so 2525 // search for the current bci in that string. 2526 address pc = fst.current()->pc(); 2527 nmethod* nm = (nmethod*) fst.current()->cb(); 2528 ScopeDesc* sd = nm->scope_desc_at( pc); 2529 char buffer[8]; 2530 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2531 size_t len = strlen(buffer); 2532 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2533 while (found != NULL) { 2534 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2535 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2536 // Check that the bci found is bracketed by terminators. 2537 break; 2538 } 2539 found = strstr(found + 1, buffer); 2540 } 2541 if (!found) { 2542 continue; 2543 } 2544 } 2545 2546 if (DebugDeoptimization && !deopt) { 2547 deopt = true; // One-time only print before deopt 2548 tty->print_cr("[BEFORE Deoptimization]"); 2549 trace_frames(); 2550 trace_stack(); 2551 } 2552 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2553 } 2554 } 2555 2556 if (DebugDeoptimization && deopt) { 2557 tty->print_cr("[AFTER Deoptimization]"); 2558 trace_frames(); 2559 } 2560} 2561 2562 2563// Make zombies 2564void JavaThread::make_zombies() { 2565 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2566 if (fst.current()->can_be_deoptimized()) { 2567 // it is a Java nmethod 2568 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2569 nm->make_not_entrant(); 2570 } 2571 } 2572} 2573#endif // PRODUCT 2574 2575 2576void JavaThread::deoptimized_wrt_marked_nmethods() { 2577 if (!has_last_Java_frame()) return; 2578 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2579 StackFrameStream fst(this, UseBiasedLocking); 2580 for(; !fst.is_done(); fst.next()) { 2581 if (fst.current()->should_be_deoptimized()) { 2582 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2583 } 2584 } 2585} 2586 2587 2588// GC support 2589static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2590 2591void JavaThread::gc_epilogue() { 2592 frames_do(frame_gc_epilogue); 2593} 2594 2595 2596static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2597 2598void JavaThread::gc_prologue() { 2599 frames_do(frame_gc_prologue); 2600} 2601 2602// If the caller is a NamedThread, then remember, in the current scope, 2603// the given JavaThread in its _processed_thread field. 2604class RememberProcessedThread: public StackObj { 2605 NamedThread* _cur_thr; 2606public: 2607 RememberProcessedThread(JavaThread* jthr) { 2608 Thread* thread = Thread::current(); 2609 if (thread->is_Named_thread()) { 2610 _cur_thr = (NamedThread *)thread; 2611 _cur_thr->set_processed_thread(jthr); 2612 } else { 2613 _cur_thr = NULL; 2614 } 2615 } 2616 2617 ~RememberProcessedThread() { 2618 if (_cur_thr) { 2619 _cur_thr->set_processed_thread(NULL); 2620 } 2621 } 2622}; 2623 2624void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 2625 // Verify that the deferred card marks have been flushed. 2626 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2627 2628 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2629 // since there may be more than one thread using each ThreadProfiler. 2630 2631 // Traverse the GCHandles 2632 Thread::oops_do(f, cf); 2633 2634 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2635 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2636 2637 if (has_last_Java_frame()) { 2638 // Record JavaThread to GC thread 2639 RememberProcessedThread rpt(this); 2640 2641 // Traverse the privileged stack 2642 if (_privileged_stack_top != NULL) { 2643 _privileged_stack_top->oops_do(f); 2644 } 2645 2646 // traverse the registered growable array 2647 if (_array_for_gc != NULL) { 2648 for (int index = 0; index < _array_for_gc->length(); index++) { 2649 f->do_oop(_array_for_gc->adr_at(index)); 2650 } 2651 } 2652 2653 // Traverse the monitor chunks 2654 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2655 chunk->oops_do(f); 2656 } 2657 2658 // Traverse the execution stack 2659 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2660 fst.current()->oops_do(f, cf, fst.register_map()); 2661 } 2662 } 2663 2664 // callee_target is never live across a gc point so NULL it here should 2665 // it still contain a methdOop. 2666 2667 set_callee_target(NULL); 2668 2669 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2670 // If we have deferred set_locals there might be oops waiting to be 2671 // written 2672 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2673 if (list != NULL) { 2674 for (int i = 0; i < list->length(); i++) { 2675 list->at(i)->oops_do(f); 2676 } 2677 } 2678 2679 // Traverse instance variables at the end since the GC may be moving things 2680 // around using this function 2681 f->do_oop((oop*) &_threadObj); 2682 f->do_oop((oop*) &_vm_result); 2683 f->do_oop((oop*) &_exception_oop); 2684 f->do_oop((oop*) &_pending_async_exception); 2685 2686 if (jvmti_thread_state() != NULL) { 2687 jvmti_thread_state()->oops_do(f); 2688 } 2689} 2690 2691void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2692 Thread::nmethods_do(cf); // (super method is a no-op) 2693 2694 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2695 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2696 2697 if (has_last_Java_frame()) { 2698 // Traverse the execution stack 2699 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2700 fst.current()->nmethods_do(cf); 2701 } 2702 } 2703} 2704 2705void JavaThread::metadata_do(void f(Metadata*)) { 2706 Thread::metadata_do(f); 2707 if (has_last_Java_frame()) { 2708 // Traverse the execution stack to call f() on the methods in the stack 2709 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2710 fst.current()->metadata_do(f); 2711 } 2712 } else if (is_Compiler_thread()) { 2713 // need to walk ciMetadata in current compile tasks to keep alive. 2714 CompilerThread* ct = (CompilerThread*)this; 2715 if (ct->env() != NULL) { 2716 ct->env()->metadata_do(f); 2717 } 2718 } 2719} 2720 2721// Printing 2722const char* _get_thread_state_name(JavaThreadState _thread_state) { 2723 switch (_thread_state) { 2724 case _thread_uninitialized: return "_thread_uninitialized"; 2725 case _thread_new: return "_thread_new"; 2726 case _thread_new_trans: return "_thread_new_trans"; 2727 case _thread_in_native: return "_thread_in_native"; 2728 case _thread_in_native_trans: return "_thread_in_native_trans"; 2729 case _thread_in_vm: return "_thread_in_vm"; 2730 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2731 case _thread_in_Java: return "_thread_in_Java"; 2732 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2733 case _thread_blocked: return "_thread_blocked"; 2734 case _thread_blocked_trans: return "_thread_blocked_trans"; 2735 default: return "unknown thread state"; 2736 } 2737} 2738 2739#ifndef PRODUCT 2740void JavaThread::print_thread_state_on(outputStream *st) const { 2741 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2742}; 2743void JavaThread::print_thread_state() const { 2744 print_thread_state_on(tty); 2745}; 2746#endif // PRODUCT 2747 2748// Called by Threads::print() for VM_PrintThreads operation 2749void JavaThread::print_on(outputStream *st) const { 2750 st->print("\"%s\" ", get_thread_name()); 2751 oop thread_oop = threadObj(); 2752 if (thread_oop != NULL && java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2753 Thread::print_on(st); 2754 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2755 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2756 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2757 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2758 } 2759#ifndef PRODUCT 2760 print_thread_state_on(st); 2761 _safepoint_state->print_on(st); 2762#endif // PRODUCT 2763} 2764 2765// Called by fatal error handler. The difference between this and 2766// JavaThread::print() is that we can't grab lock or allocate memory. 2767void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2768 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2769 oop thread_obj = threadObj(); 2770 if (thread_obj != NULL) { 2771 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2772 } 2773 st->print(" ["); 2774 st->print("%s", _get_thread_state_name(_thread_state)); 2775 if (osthread()) { 2776 st->print(", id=%d", osthread()->thread_id()); 2777 } 2778 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2779 _stack_base - _stack_size, _stack_base); 2780 st->print("]"); 2781 return; 2782} 2783 2784// Verification 2785 2786static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2787 2788void JavaThread::verify() { 2789 // Verify oops in the thread. 2790 oops_do(&VerifyOopClosure::verify_oop, NULL); 2791 2792 // Verify the stack frames. 2793 frames_do(frame_verify); 2794} 2795 2796// CR 6300358 (sub-CR 2137150) 2797// Most callers of this method assume that it can't return NULL but a 2798// thread may not have a name whilst it is in the process of attaching to 2799// the VM - see CR 6412693, and there are places where a JavaThread can be 2800// seen prior to having it's threadObj set (eg JNI attaching threads and 2801// if vm exit occurs during initialization). These cases can all be accounted 2802// for such that this method never returns NULL. 2803const char* JavaThread::get_thread_name() const { 2804#ifdef ASSERT 2805 // early safepoints can hit while current thread does not yet have TLS 2806 if (!SafepointSynchronize::is_at_safepoint()) { 2807 Thread *cur = Thread::current(); 2808 if (!(cur->is_Java_thread() && cur == this)) { 2809 // Current JavaThreads are allowed to get their own name without 2810 // the Threads_lock. 2811 assert_locked_or_safepoint(Threads_lock); 2812 } 2813 } 2814#endif // ASSERT 2815 return get_thread_name_string(); 2816} 2817 2818// Returns a non-NULL representation of this thread's name, or a suitable 2819// descriptive string if there is no set name 2820const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2821 const char* name_str; 2822 oop thread_obj = threadObj(); 2823 if (thread_obj != NULL) { 2824 typeArrayOop name = java_lang_Thread::name(thread_obj); 2825 if (name != NULL) { 2826 if (buf == NULL) { 2827 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2828 } 2829 else { 2830 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2831 } 2832 } 2833 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2834 name_str = "<no-name - thread is attaching>"; 2835 } 2836 else { 2837 name_str = Thread::name(); 2838 } 2839 } 2840 else { 2841 name_str = Thread::name(); 2842 } 2843 assert(name_str != NULL, "unexpected NULL thread name"); 2844 return name_str; 2845} 2846 2847 2848const char* JavaThread::get_threadgroup_name() const { 2849 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2850 oop thread_obj = threadObj(); 2851 if (thread_obj != NULL) { 2852 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2853 if (thread_group != NULL) { 2854 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2855 // ThreadGroup.name can be null 2856 if (name != NULL) { 2857 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2858 return str; 2859 } 2860 } 2861 } 2862 return NULL; 2863} 2864 2865const char* JavaThread::get_parent_name() const { 2866 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2867 oop thread_obj = threadObj(); 2868 if (thread_obj != NULL) { 2869 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2870 if (thread_group != NULL) { 2871 oop parent = java_lang_ThreadGroup::parent(thread_group); 2872 if (parent != NULL) { 2873 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2874 // ThreadGroup.name can be null 2875 if (name != NULL) { 2876 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2877 return str; 2878 } 2879 } 2880 } 2881 } 2882 return NULL; 2883} 2884 2885ThreadPriority JavaThread::java_priority() const { 2886 oop thr_oop = threadObj(); 2887 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2888 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2889 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2890 return priority; 2891} 2892 2893void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2894 2895 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2896 // Link Java Thread object <-> C++ Thread 2897 2898 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2899 // and put it into a new Handle. The Handle "thread_oop" can then 2900 // be used to pass the C++ thread object to other methods. 2901 2902 // Set the Java level thread object (jthread) field of the 2903 // new thread (a JavaThread *) to C++ thread object using the 2904 // "thread_oop" handle. 2905 2906 // Set the thread field (a JavaThread *) of the 2907 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2908 2909 Handle thread_oop(Thread::current(), 2910 JNIHandles::resolve_non_null(jni_thread)); 2911 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 2912 "must be initialized"); 2913 set_threadObj(thread_oop()); 2914 java_lang_Thread::set_thread(thread_oop(), this); 2915 2916 if (prio == NoPriority) { 2917 prio = java_lang_Thread::priority(thread_oop()); 2918 assert(prio != NoPriority, "A valid priority should be present"); 2919 } 2920 2921 // Push the Java priority down to the native thread; needs Threads_lock 2922 Thread::set_priority(this, prio); 2923 2924 // Add the new thread to the Threads list and set it in motion. 2925 // We must have threads lock in order to call Threads::add. 2926 // It is crucial that we do not block before the thread is 2927 // added to the Threads list for if a GC happens, then the java_thread oop 2928 // will not be visited by GC. 2929 Threads::add(this); 2930} 2931 2932oop JavaThread::current_park_blocker() { 2933 // Support for JSR-166 locks 2934 oop thread_oop = threadObj(); 2935 if (thread_oop != NULL && 2936 JDK_Version::current().supports_thread_park_blocker()) { 2937 return java_lang_Thread::park_blocker(thread_oop); 2938 } 2939 return NULL; 2940} 2941 2942 2943void JavaThread::print_stack_on(outputStream* st) { 2944 if (!has_last_Java_frame()) return; 2945 ResourceMark rm; 2946 HandleMark hm; 2947 2948 RegisterMap reg_map(this); 2949 vframe* start_vf = last_java_vframe(®_map); 2950 int count = 0; 2951 for (vframe* f = start_vf; f; f = f->sender() ) { 2952 if (f->is_java_frame()) { 2953 javaVFrame* jvf = javaVFrame::cast(f); 2954 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 2955 2956 // Print out lock information 2957 if (JavaMonitorsInStackTrace) { 2958 jvf->print_lock_info_on(st, count); 2959 } 2960 } else { 2961 // Ignore non-Java frames 2962 } 2963 2964 // Bail-out case for too deep stacks 2965 count++; 2966 if (MaxJavaStackTraceDepth == count) return; 2967 } 2968} 2969 2970 2971// JVMTI PopFrame support 2972void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 2973 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 2974 if (in_bytes(size_in_bytes) != 0) { 2975 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 2976 _popframe_preserved_args_size = in_bytes(size_in_bytes); 2977 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 2978 } 2979} 2980 2981void* JavaThread::popframe_preserved_args() { 2982 return _popframe_preserved_args; 2983} 2984 2985ByteSize JavaThread::popframe_preserved_args_size() { 2986 return in_ByteSize(_popframe_preserved_args_size); 2987} 2988 2989WordSize JavaThread::popframe_preserved_args_size_in_words() { 2990 int sz = in_bytes(popframe_preserved_args_size()); 2991 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 2992 return in_WordSize(sz / wordSize); 2993} 2994 2995void JavaThread::popframe_free_preserved_args() { 2996 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 2997 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 2998 _popframe_preserved_args = NULL; 2999 _popframe_preserved_args_size = 0; 3000} 3001 3002#ifndef PRODUCT 3003 3004void JavaThread::trace_frames() { 3005 tty->print_cr("[Describe stack]"); 3006 int frame_no = 1; 3007 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3008 tty->print(" %d. ", frame_no++); 3009 fst.current()->print_value_on(tty,this); 3010 tty->cr(); 3011 } 3012} 3013 3014class PrintAndVerifyOopClosure: public OopClosure { 3015 protected: 3016 template <class T> inline void do_oop_work(T* p) { 3017 oop obj = oopDesc::load_decode_heap_oop(p); 3018 if (obj == NULL) return; 3019 tty->print(INTPTR_FORMAT ": ", p); 3020 if (obj->is_oop_or_null()) { 3021 if (obj->is_objArray()) { 3022 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3023 } else { 3024 obj->print(); 3025 } 3026 } else { 3027 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3028 } 3029 tty->cr(); 3030 } 3031 public: 3032 virtual void do_oop(oop* p) { do_oop_work(p); } 3033 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3034}; 3035 3036 3037static void oops_print(frame* f, const RegisterMap *map) { 3038 PrintAndVerifyOopClosure print; 3039 f->print_value(); 3040 f->oops_do(&print, NULL, (RegisterMap*)map); 3041} 3042 3043// Print our all the locations that contain oops and whether they are 3044// valid or not. This useful when trying to find the oldest frame 3045// where an oop has gone bad since the frame walk is from youngest to 3046// oldest. 3047void JavaThread::trace_oops() { 3048 tty->print_cr("[Trace oops]"); 3049 frames_do(oops_print); 3050} 3051 3052 3053#ifdef ASSERT 3054// Print or validate the layout of stack frames 3055void JavaThread::print_frame_layout(int depth, bool validate_only) { 3056 ResourceMark rm; 3057 PRESERVE_EXCEPTION_MARK; 3058 FrameValues values; 3059 int frame_no = 0; 3060 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3061 fst.current()->describe(values, ++frame_no); 3062 if (depth == frame_no) break; 3063 } 3064 if (validate_only) { 3065 values.validate(); 3066 } else { 3067 tty->print_cr("[Describe stack layout]"); 3068 values.print(this); 3069 } 3070} 3071#endif 3072 3073void JavaThread::trace_stack_from(vframe* start_vf) { 3074 ResourceMark rm; 3075 int vframe_no = 1; 3076 for (vframe* f = start_vf; f; f = f->sender() ) { 3077 if (f->is_java_frame()) { 3078 javaVFrame::cast(f)->print_activation(vframe_no++); 3079 } else { 3080 f->print(); 3081 } 3082 if (vframe_no > StackPrintLimit) { 3083 tty->print_cr("...<more frames>..."); 3084 return; 3085 } 3086 } 3087} 3088 3089 3090void JavaThread::trace_stack() { 3091 if (!has_last_Java_frame()) return; 3092 ResourceMark rm; 3093 HandleMark hm; 3094 RegisterMap reg_map(this); 3095 trace_stack_from(last_java_vframe(®_map)); 3096} 3097 3098 3099#endif // PRODUCT 3100 3101 3102javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3103 assert(reg_map != NULL, "a map must be given"); 3104 frame f = last_frame(); 3105 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3106 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3107 } 3108 return NULL; 3109} 3110 3111 3112Klass* JavaThread::security_get_caller_class(int depth) { 3113 vframeStream vfst(this); 3114 vfst.security_get_caller_frame(depth); 3115 if (!vfst.at_end()) { 3116 return vfst.method()->method_holder(); 3117 } 3118 return NULL; 3119} 3120 3121static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3122 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3123 CompileBroker::compiler_thread_loop(); 3124} 3125 3126// Create a CompilerThread 3127CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3128: JavaThread(&compiler_thread_entry) { 3129 _env = NULL; 3130 _log = NULL; 3131 _task = NULL; 3132 _queue = queue; 3133 _counters = counters; 3134 _buffer_blob = NULL; 3135 _scanned_nmethod = NULL; 3136 3137#ifndef PRODUCT 3138 _ideal_graph_printer = NULL; 3139#endif 3140} 3141 3142void CompilerThread::oops_do(OopClosure* f, CodeBlobClosure* cf) { 3143 JavaThread::oops_do(f, cf); 3144 if (_scanned_nmethod != NULL && cf != NULL) { 3145 // Safepoints can occur when the sweeper is scanning an nmethod so 3146 // process it here to make sure it isn't unloaded in the middle of 3147 // a scan. 3148 cf->do_code_blob(_scanned_nmethod); 3149 } 3150} 3151 3152// ======= Threads ======== 3153 3154// The Threads class links together all active threads, and provides 3155// operations over all threads. It is protected by its own Mutex 3156// lock, which is also used in other contexts to protect thread 3157// operations from having the thread being operated on from exiting 3158// and going away unexpectedly (e.g., safepoint synchronization) 3159 3160JavaThread* Threads::_thread_list = NULL; 3161int Threads::_number_of_threads = 0; 3162int Threads::_number_of_non_daemon_threads = 0; 3163int Threads::_return_code = 0; 3164size_t JavaThread::_stack_size_at_create = 0; 3165#ifdef ASSERT 3166bool Threads::_vm_complete = false; 3167#endif 3168 3169// All JavaThreads 3170#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3171 3172void os_stream(); 3173 3174// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3175void Threads::threads_do(ThreadClosure* tc) { 3176 assert_locked_or_safepoint(Threads_lock); 3177 // ALL_JAVA_THREADS iterates through all JavaThreads 3178 ALL_JAVA_THREADS(p) { 3179 tc->do_thread(p); 3180 } 3181 // Someday we could have a table or list of all non-JavaThreads. 3182 // For now, just manually iterate through them. 3183 tc->do_thread(VMThread::vm_thread()); 3184 Universe::heap()->gc_threads_do(tc); 3185 WatcherThread *wt = WatcherThread::watcher_thread(); 3186 // Strictly speaking, the following NULL check isn't sufficient to make sure 3187 // the data for WatcherThread is still valid upon being examined. However, 3188 // considering that WatchThread terminates when the VM is on the way to 3189 // exit at safepoint, the chance of the above is extremely small. The right 3190 // way to prevent termination of WatcherThread would be to acquire 3191 // Terminator_lock, but we can't do that without violating the lock rank 3192 // checking in some cases. 3193 if (wt != NULL) 3194 tc->do_thread(wt); 3195 3196 // If CompilerThreads ever become non-JavaThreads, add them here 3197} 3198 3199jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3200 3201 extern void JDK_Version_init(); 3202 3203 // Check version 3204 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3205 3206 // Initialize the output stream module 3207 ostream_init(); 3208 3209 // Process java launcher properties. 3210 Arguments::process_sun_java_launcher_properties(args); 3211 3212 // Initialize the os module before using TLS 3213 os::init(); 3214 3215 // Initialize system properties. 3216 Arguments::init_system_properties(); 3217 3218 // So that JDK version can be used as a discrimintor when parsing arguments 3219 JDK_Version_init(); 3220 3221 // Update/Initialize System properties after JDK version number is known 3222 Arguments::init_version_specific_system_properties(); 3223 3224 // Parse arguments 3225 jint parse_result = Arguments::parse(args); 3226 if (parse_result != JNI_OK) return parse_result; 3227 3228 if (PauseAtStartup) { 3229 os::pause(); 3230 } 3231 3232#ifndef USDT2 3233 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3234#else /* USDT2 */ 3235 HOTSPOT_VM_INIT_BEGIN(); 3236#endif /* USDT2 */ 3237 3238 // Record VM creation timing statistics 3239 TraceVmCreationTime create_vm_timer; 3240 create_vm_timer.start(); 3241 3242 // Timing (must come after argument parsing) 3243 TraceTime timer("Create VM", TraceStartupTime); 3244 3245 // Initialize the os module after parsing the args 3246 jint os_init_2_result = os::init_2(); 3247 if (os_init_2_result != JNI_OK) return os_init_2_result; 3248 3249 // intialize TLS 3250 ThreadLocalStorage::init(); 3251 3252 // Bootstrap native memory tracking, so it can start recording memory 3253 // activities before worker thread is started. This is the first phase 3254 // of bootstrapping, VM is currently running in single-thread mode. 3255 MemTracker::bootstrap_single_thread(); 3256 3257 // Initialize output stream logging 3258 ostream_init_log(); 3259 3260 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3261 // Must be before create_vm_init_agents() 3262 if (Arguments::init_libraries_at_startup()) { 3263 convert_vm_init_libraries_to_agents(); 3264 } 3265 3266 // Launch -agentlib/-agentpath and converted -Xrun agents 3267 if (Arguments::init_agents_at_startup()) { 3268 create_vm_init_agents(); 3269 } 3270 3271 // Initialize Threads state 3272 _thread_list = NULL; 3273 _number_of_threads = 0; 3274 _number_of_non_daemon_threads = 0; 3275 3276 // Initialize global data structures and create system classes in heap 3277 vm_init_globals(); 3278 3279 // Attach the main thread to this os thread 3280 JavaThread* main_thread = new JavaThread(); 3281 main_thread->set_thread_state(_thread_in_vm); 3282 // must do this before set_active_handles and initialize_thread_local_storage 3283 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3284 // change the stack size recorded here to one based on the java thread 3285 // stacksize. This adjusted size is what is used to figure the placement 3286 // of the guard pages. 3287 main_thread->record_stack_base_and_size(); 3288 main_thread->initialize_thread_local_storage(); 3289 3290 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3291 3292 if (!main_thread->set_as_starting_thread()) { 3293 vm_shutdown_during_initialization( 3294 "Failed necessary internal allocation. Out of swap space"); 3295 delete main_thread; 3296 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3297 return JNI_ENOMEM; 3298 } 3299 3300 // Enable guard page *after* os::create_main_thread(), otherwise it would 3301 // crash Linux VM, see notes in os_linux.cpp. 3302 main_thread->create_stack_guard_pages(); 3303 3304 // Initialize Java-Level synchronization subsystem 3305 ObjectMonitor::Initialize() ; 3306 3307 // Second phase of bootstrapping, VM is about entering multi-thread mode 3308 MemTracker::bootstrap_multi_thread(); 3309 3310 // Initialize global modules 3311 jint status = init_globals(); 3312 if (status != JNI_OK) { 3313 delete main_thread; 3314 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3315 return status; 3316 } 3317 3318 // Should be done after the heap is fully created 3319 main_thread->cache_global_variables(); 3320 3321 HandleMark hm; 3322 3323 { MutexLocker mu(Threads_lock); 3324 Threads::add(main_thread); 3325 } 3326 3327 // Any JVMTI raw monitors entered in onload will transition into 3328 // real raw monitor. VM is setup enough here for raw monitor enter. 3329 JvmtiExport::transition_pending_onload_raw_monitors(); 3330 3331 if (VerifyBeforeGC && 3332 Universe::heap()->total_collections() >= VerifyGCStartAt) { 3333 Universe::heap()->prepare_for_verify(); 3334 Universe::verify(); // make sure we're starting with a clean slate 3335 } 3336 3337 // Fully start NMT 3338 MemTracker::start(); 3339 3340 // Create the VMThread 3341 { TraceTime timer("Start VMThread", TraceStartupTime); 3342 VMThread::create(); 3343 Thread* vmthread = VMThread::vm_thread(); 3344 3345 if (!os::create_thread(vmthread, os::vm_thread)) 3346 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3347 3348 // Wait for the VM thread to become ready, and VMThread::run to initialize 3349 // Monitors can have spurious returns, must always check another state flag 3350 { 3351 MutexLocker ml(Notify_lock); 3352 os::start_thread(vmthread); 3353 while (vmthread->active_handles() == NULL) { 3354 Notify_lock->wait(); 3355 } 3356 } 3357 } 3358 3359 assert (Universe::is_fully_initialized(), "not initialized"); 3360 EXCEPTION_MARK; 3361 3362 // At this point, the Universe is initialized, but we have not executed 3363 // any byte code. Now is a good time (the only time) to dump out the 3364 // internal state of the JVM for sharing. 3365 if (DumpSharedSpaces) { 3366 MetaspaceShared::preload_and_dump(CHECK_0); 3367 ShouldNotReachHere(); 3368 } 3369 3370 // Always call even when there are not JVMTI environments yet, since environments 3371 // may be attached late and JVMTI must track phases of VM execution 3372 JvmtiExport::enter_start_phase(); 3373 3374 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3375 JvmtiExport::post_vm_start(); 3376 3377 { 3378 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3379 3380 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3381 create_vm_init_libraries(); 3382 } 3383 3384 if (InitializeJavaLangString) { 3385 initialize_class(vmSymbols::java_lang_String(), CHECK_0); 3386 } else { 3387 warning("java.lang.String not initialized"); 3388 } 3389 3390 if (AggressiveOpts) { 3391 { 3392 // Forcibly initialize java/util/HashMap and mutate the private 3393 // static final "frontCacheEnabled" field before we start creating instances 3394#ifdef ASSERT 3395 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3396 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 3397#endif 3398 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3399 KlassHandle k = KlassHandle(THREAD, k_o); 3400 guarantee(k.not_null(), "Must find java/util/HashMap"); 3401 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3402 ik->initialize(CHECK_0); 3403 fieldDescriptor fd; 3404 // Possible we might not find this field; if so, don't break 3405 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3406 k()->java_mirror()->bool_field_put(fd.offset(), true); 3407 } 3408 } 3409 3410 if (UseStringCache) { 3411 // Forcibly initialize java/lang/StringValue and mutate the private 3412 // static final "stringCacheEnabled" field before we start creating instances 3413 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0); 3414 // Possible that StringValue isn't present: if so, silently don't break 3415 if (k_o != NULL) { 3416 KlassHandle k = KlassHandle(THREAD, k_o); 3417 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3418 ik->initialize(CHECK_0); 3419 fieldDescriptor fd; 3420 // Possible we might not find this field: if so, silently don't break 3421 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3422 k()->java_mirror()->bool_field_put(fd.offset(), true); 3423 } 3424 } 3425 } 3426 } 3427 3428 // Initialize java_lang.System (needed before creating the thread) 3429 if (InitializeJavaLangSystem) { 3430 initialize_class(vmSymbols::java_lang_System(), CHECK_0); 3431 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0); 3432 Handle thread_group = create_initial_thread_group(CHECK_0); 3433 Universe::set_main_thread_group(thread_group()); 3434 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0); 3435 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 3436 main_thread->set_threadObj(thread_object); 3437 // Set thread status to running since main thread has 3438 // been started and running. 3439 java_lang_Thread::set_thread_status(thread_object, 3440 java_lang_Thread::RUNNABLE); 3441 3442 // The VM preresolve methods to these classes. Make sure that get initialized 3443 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0); 3444 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0); 3445 // The VM creates & returns objects of this class. Make sure it's initialized. 3446 initialize_class(vmSymbols::java_lang_Class(), CHECK_0); 3447 call_initializeSystemClass(CHECK_0); 3448 3449 // get the Java runtime name after java.lang.System is initialized 3450 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3451 } else { 3452 warning("java.lang.System not initialized"); 3453 } 3454 3455 // an instance of OutOfMemory exception has been allocated earlier 3456 if (InitializeJavaLangExceptionsErrors) { 3457 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0); 3458 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0); 3459 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0); 3460 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0); 3461 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0); 3462 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0); 3463 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0); 3464 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0); 3465 } else { 3466 warning("java.lang.OutOfMemoryError has not been initialized"); 3467 warning("java.lang.NullPointerException has not been initialized"); 3468 warning("java.lang.ClassCastException has not been initialized"); 3469 warning("java.lang.ArrayStoreException has not been initialized"); 3470 warning("java.lang.ArithmeticException has not been initialized"); 3471 warning("java.lang.StackOverflowError has not been initialized"); 3472 warning("java.lang.IllegalArgumentException has not been initialized"); 3473 } 3474 } 3475 3476 // See : bugid 4211085. 3477 // Background : the static initializer of java.lang.Compiler tries to read 3478 // property"java.compiler" and read & write property "java.vm.info". 3479 // When a security manager is installed through the command line 3480 // option "-Djava.security.manager", the above properties are not 3481 // readable and the static initializer for java.lang.Compiler fails 3482 // resulting in a NoClassDefFoundError. This can happen in any 3483 // user code which calls methods in java.lang.Compiler. 3484 // Hack : the hack is to pre-load and initialize this class, so that only 3485 // system domains are on the stack when the properties are read. 3486 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3487 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3488 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3489 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3490 // Once that is done, we should remove this hack. 3491 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0); 3492 3493 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3494 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3495 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3496 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3497 // This should also be taken out as soon as 4211383 gets fixed. 3498 reset_vm_info_property(CHECK_0); 3499 3500 quicken_jni_functions(); 3501 3502 // Must be run after init_ft which initializes ft_enabled 3503 if (TRACE_INITIALIZE() != JNI_OK) { 3504 vm_exit_during_initialization("Failed to initialize tracing backend"); 3505 } 3506 3507 // Set flag that basic initialization has completed. Used by exceptions and various 3508 // debug stuff, that does not work until all basic classes have been initialized. 3509 set_init_completed(); 3510 3511#ifndef USDT2 3512 HS_DTRACE_PROBE(hotspot, vm__init__end); 3513#else /* USDT2 */ 3514 HOTSPOT_VM_INIT_END(); 3515#endif /* USDT2 */ 3516 3517 // record VM initialization completion time 3518 Management::record_vm_init_completed(); 3519 3520 // Compute system loader. Note that this has to occur after set_init_completed, since 3521 // valid exceptions may be thrown in the process. 3522 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3523 // set_init_completed has just been called, causing exceptions not to be shortcut 3524 // anymore. We call vm_exit_during_initialization directly instead. 3525 SystemDictionary::compute_java_system_loader(THREAD); 3526 if (HAS_PENDING_EXCEPTION) { 3527 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3528 } 3529 3530#ifndef SERIALGC 3531 // Support for ConcurrentMarkSweep. This should be cleaned up 3532 // and better encapsulated. The ugly nested if test would go away 3533 // once things are properly refactored. XXX YSR 3534 if (UseConcMarkSweepGC || UseG1GC) { 3535 if (UseConcMarkSweepGC) { 3536 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3537 } else { 3538 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3539 } 3540 if (HAS_PENDING_EXCEPTION) { 3541 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3542 } 3543 } 3544#endif // SERIALGC 3545 3546 // Always call even when there are not JVMTI environments yet, since environments 3547 // may be attached late and JVMTI must track phases of VM execution 3548 JvmtiExport::enter_live_phase(); 3549 3550 // Signal Dispatcher needs to be started before VMInit event is posted 3551 os::signal_init(); 3552 3553 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3554 if (!DisableAttachMechanism) { 3555 if (StartAttachListener || AttachListener::init_at_startup()) { 3556 AttachListener::init(); 3557 } 3558 } 3559 3560 // Launch -Xrun agents 3561 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3562 // back-end can launch with -Xdebug -Xrunjdwp. 3563 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3564 create_vm_init_libraries(); 3565 } 3566 3567 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3568 JvmtiExport::post_vm_initialized(); 3569 3570 if (!TRACE_START()) { 3571 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3572 } 3573 3574 if (CleanChunkPoolAsync) { 3575 Chunk::start_chunk_pool_cleaner_task(); 3576 } 3577 3578 // initialize compiler(s) 3579 CompileBroker::compilation_init(); 3580 3581 Management::initialize(THREAD); 3582 if (HAS_PENDING_EXCEPTION) { 3583 // management agent fails to start possibly due to 3584 // configuration problem and is responsible for printing 3585 // stack trace if appropriate. Simply exit VM. 3586 vm_exit(1); 3587 } 3588 3589 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3590 if (Arguments::has_alloc_profile()) AllocationProfiler::engage(); 3591 if (MemProfiling) MemProfiler::engage(); 3592 StatSampler::engage(); 3593 if (CheckJNICalls) JniPeriodicChecker::engage(); 3594 3595 BiasedLocking::init(); 3596 3597 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3598 call_postVMInitHook(THREAD); 3599 // The Java side of PostVMInitHook.run must deal with all 3600 // exceptions and provide means of diagnosis. 3601 if (HAS_PENDING_EXCEPTION) { 3602 CLEAR_PENDING_EXCEPTION; 3603 } 3604 } 3605 3606 // Start up the WatcherThread if there are any periodic tasks 3607 // NOTE: All PeriodicTasks should be registered by now. If they 3608 // aren't, late joiners might appear to start slowly (we might 3609 // take a while to process their first tick). 3610 if (PeriodicTask::num_tasks() > 0) { 3611 WatcherThread::start(); 3612 } 3613 3614 // Give os specific code one last chance to start 3615 os::init_3(); 3616 3617 create_vm_timer.end(); 3618#ifdef ASSERT 3619 _vm_complete = true; 3620#endif 3621 return JNI_OK; 3622} 3623 3624// type for the Agent_OnLoad and JVM_OnLoad entry points 3625extern "C" { 3626 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3627} 3628// Find a command line agent library and return its entry point for 3629// -agentlib: -agentpath: -Xrun 3630// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3631static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3632 OnLoadEntry_t on_load_entry = NULL; 3633 void *library = agent->os_lib(); // check if we have looked it up before 3634 3635 if (library == NULL) { 3636 char buffer[JVM_MAXPATHLEN]; 3637 char ebuf[1024]; 3638 const char *name = agent->name(); 3639 const char *msg = "Could not find agent library "; 3640 3641 if (agent->is_absolute_path()) { 3642 library = os::dll_load(name, ebuf, sizeof ebuf); 3643 if (library == NULL) { 3644 const char *sub_msg = " in absolute path, with error: "; 3645 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3646 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3647 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3648 // If we can't find the agent, exit. 3649 vm_exit_during_initialization(buf, NULL); 3650 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3651 } 3652 } else { 3653 // Try to load the agent from the standard dll directory 3654 os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), name); 3655 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3656#ifdef KERNEL 3657 // Download instrument dll 3658 if (library == NULL && strcmp(name, "instrument") == 0) { 3659 char *props = Arguments::get_kernel_properties(); 3660 char *home = Arguments::get_java_home(); 3661 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false" 3662 " sun.jkernel.DownloadManager -download client_jvm"; 3663 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1; 3664 char *cmd = NEW_C_HEAP_ARRAY(char, length, mtThread); 3665 jio_snprintf(cmd, length, fmt, home, props); 3666 int status = os::fork_and_exec(cmd); 3667 FreeHeap(props); 3668 if (status == -1) { 3669 warning(cmd); 3670 vm_exit_during_initialization("fork_and_exec failed: %s", 3671 strerror(errno)); 3672 } 3673 FREE_C_HEAP_ARRAY(char, cmd, mtThread); 3674 // when this comes back the instrument.dll should be where it belongs. 3675 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3676 } 3677#endif // KERNEL 3678 if (library == NULL) { // Try the local directory 3679 char ns[1] = {0}; 3680 os::dll_build_name(buffer, sizeof(buffer), ns, name); 3681 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3682 if (library == NULL) { 3683 const char *sub_msg = " on the library path, with error: "; 3684 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3685 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3686 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3687 // If we can't find the agent, exit. 3688 vm_exit_during_initialization(buf, NULL); 3689 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3690 } 3691 } 3692 } 3693 agent->set_os_lib(library); 3694 } 3695 3696 // Find the OnLoad function. 3697 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3698 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index])); 3699 if (on_load_entry != NULL) break; 3700 } 3701 return on_load_entry; 3702} 3703 3704// Find the JVM_OnLoad entry point 3705static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3706 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3707 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3708} 3709 3710// Find the Agent_OnLoad entry point 3711static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3712 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3713 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3714} 3715 3716// For backwards compatibility with -Xrun 3717// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3718// treated like -agentpath: 3719// Must be called before agent libraries are created 3720void Threads::convert_vm_init_libraries_to_agents() { 3721 AgentLibrary* agent; 3722 AgentLibrary* next; 3723 3724 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3725 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3726 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3727 3728 // If there is an JVM_OnLoad function it will get called later, 3729 // otherwise see if there is an Agent_OnLoad 3730 if (on_load_entry == NULL) { 3731 on_load_entry = lookup_agent_on_load(agent); 3732 if (on_load_entry != NULL) { 3733 // switch it to the agent list -- so that Agent_OnLoad will be called, 3734 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3735 Arguments::convert_library_to_agent(agent); 3736 } else { 3737 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3738 } 3739 } 3740 } 3741} 3742 3743// Create agents for -agentlib: -agentpath: and converted -Xrun 3744// Invokes Agent_OnLoad 3745// Called very early -- before JavaThreads exist 3746void Threads::create_vm_init_agents() { 3747 extern struct JavaVM_ main_vm; 3748 AgentLibrary* agent; 3749 3750 JvmtiExport::enter_onload_phase(); 3751 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3752 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3753 3754 if (on_load_entry != NULL) { 3755 // Invoke the Agent_OnLoad function 3756 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3757 if (err != JNI_OK) { 3758 vm_exit_during_initialization("agent library failed to init", agent->name()); 3759 } 3760 } else { 3761 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3762 } 3763 } 3764 JvmtiExport::enter_primordial_phase(); 3765} 3766 3767extern "C" { 3768 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3769} 3770 3771void Threads::shutdown_vm_agents() { 3772 // Send any Agent_OnUnload notifications 3773 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3774 extern struct JavaVM_ main_vm; 3775 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3776 3777 // Find the Agent_OnUnload function. 3778 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3779 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3780 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3781 3782 // Invoke the Agent_OnUnload function 3783 if (unload_entry != NULL) { 3784 JavaThread* thread = JavaThread::current(); 3785 ThreadToNativeFromVM ttn(thread); 3786 HandleMark hm(thread); 3787 (*unload_entry)(&main_vm); 3788 break; 3789 } 3790 } 3791 } 3792} 3793 3794// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3795// Invokes JVM_OnLoad 3796void Threads::create_vm_init_libraries() { 3797 extern struct JavaVM_ main_vm; 3798 AgentLibrary* agent; 3799 3800 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3801 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3802 3803 if (on_load_entry != NULL) { 3804 // Invoke the JVM_OnLoad function 3805 JavaThread* thread = JavaThread::current(); 3806 ThreadToNativeFromVM ttn(thread); 3807 HandleMark hm(thread); 3808 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3809 if (err != JNI_OK) { 3810 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3811 } 3812 } else { 3813 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3814 } 3815 } 3816} 3817 3818// Last thread running calls java.lang.Shutdown.shutdown() 3819void JavaThread::invoke_shutdown_hooks() { 3820 HandleMark hm(this); 3821 3822 // We could get here with a pending exception, if so clear it now. 3823 if (this->has_pending_exception()) { 3824 this->clear_pending_exception(); 3825 } 3826 3827 EXCEPTION_MARK; 3828 Klass* k = 3829 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3830 THREAD); 3831 if (k != NULL) { 3832 // SystemDictionary::resolve_or_null will return null if there was 3833 // an exception. If we cannot load the Shutdown class, just don't 3834 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3835 // and finalizers (if runFinalizersOnExit is set) won't be run. 3836 // Note that if a shutdown hook was registered or runFinalizersOnExit 3837 // was called, the Shutdown class would have already been loaded 3838 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3839 instanceKlassHandle shutdown_klass (THREAD, k); 3840 JavaValue result(T_VOID); 3841 JavaCalls::call_static(&result, 3842 shutdown_klass, 3843 vmSymbols::shutdown_method_name(), 3844 vmSymbols::void_method_signature(), 3845 THREAD); 3846 } 3847 CLEAR_PENDING_EXCEPTION; 3848} 3849 3850// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3851// the program falls off the end of main(). Another VM exit path is through 3852// vm_exit() when the program calls System.exit() to return a value or when 3853// there is a serious error in VM. The two shutdown paths are not exactly 3854// the same, but they share Shutdown.shutdown() at Java level and before_exit() 3855// and VM_Exit op at VM level. 3856// 3857// Shutdown sequence: 3858// + Shutdown native memory tracking if it is on 3859// + Wait until we are the last non-daemon thread to execute 3860// <-- every thing is still working at this moment --> 3861// + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3862// shutdown hooks, run finalizers if finalization-on-exit 3863// + Call before_exit(), prepare for VM exit 3864// > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3865// currently the only user of this mechanism is File.deleteOnExit()) 3866// > stop flat profiler, StatSampler, watcher thread, CMS threads, 3867// post thread end and vm death events to JVMTI, 3868// stop signal thread 3869// + Call JavaThread::exit(), it will: 3870// > release JNI handle blocks, remove stack guard pages 3871// > remove this thread from Threads list 3872// <-- no more Java code from this thread after this point --> 3873// + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3874// the compiler threads at safepoint 3875// <-- do not use anything that could get blocked by Safepoint --> 3876// + Disable tracing at JNI/JVM barriers 3877// + Set _vm_exited flag for threads that are still running native code 3878// + Delete this thread 3879// + Call exit_globals() 3880// > deletes tty 3881// > deletes PerfMemory resources 3882// + Return to caller 3883 3884bool Threads::destroy_vm() { 3885 JavaThread* thread = JavaThread::current(); 3886 3887#ifdef ASSERT 3888 _vm_complete = false; 3889#endif 3890 // Wait until we are the last non-daemon thread to execute 3891 { MutexLocker nu(Threads_lock); 3892 while (Threads::number_of_non_daemon_threads() > 1 ) 3893 // This wait should make safepoint checks, wait without a timeout, 3894 // and wait as a suspend-equivalent condition. 3895 // 3896 // Note: If the FlatProfiler is running and this thread is waiting 3897 // for another non-daemon thread to finish, then the FlatProfiler 3898 // is waiting for the external suspend request on this thread to 3899 // complete. wait_for_ext_suspend_completion() will eventually 3900 // timeout, but that takes time. Making this wait a suspend- 3901 // equivalent condition solves that timeout problem. 3902 // 3903 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3904 Mutex::_as_suspend_equivalent_flag); 3905 } 3906 3907 // Shutdown NMT before exit. Otherwise, 3908 // it will run into trouble when system destroys static variables. 3909 MemTracker::shutdown(MemTracker::NMT_normal); 3910 3911 // Hang forever on exit if we are reporting an error. 3912 if (ShowMessageBoxOnError && is_error_reported()) { 3913 os::infinite_sleep(); 3914 } 3915 os::wait_for_keypress_at_exit(); 3916 3917 if (JDK_Version::is_jdk12x_version()) { 3918 // We are the last thread running, so check if finalizers should be run. 3919 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3920 HandleMark rm(thread); 3921 Universe::run_finalizers_on_exit(); 3922 } else { 3923 // run Java level shutdown hooks 3924 thread->invoke_shutdown_hooks(); 3925 } 3926 3927 before_exit(thread); 3928 3929 thread->exit(true); 3930 3931 // Stop VM thread. 3932 { 3933 // 4945125 The vm thread comes to a safepoint during exit. 3934 // GC vm_operations can get caught at the safepoint, and the 3935 // heap is unparseable if they are caught. Grab the Heap_lock 3936 // to prevent this. The GC vm_operations will not be able to 3937 // queue until after the vm thread is dead. 3938 // After this point, we'll never emerge out of the safepoint before 3939 // the VM exits, so concurrent GC threads do not need to be explicitly 3940 // stopped; they remain inactive until the process exits. 3941 // Note: some concurrent G1 threads may be running during a safepoint, 3942 // but these will not be accessing the heap, just some G1-specific side 3943 // data structures that are not accessed by any other threads but them 3944 // after this point in a terminal safepoint. 3945 3946 MutexLocker ml(Heap_lock); 3947 3948 VMThread::wait_for_vm_thread_exit(); 3949 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 3950 VMThread::destroy(); 3951 } 3952 3953 // clean up ideal graph printers 3954#if defined(COMPILER2) && !defined(PRODUCT) 3955 IdealGraphPrinter::clean_up(); 3956#endif 3957 3958 // Now, all Java threads are gone except daemon threads. Daemon threads 3959 // running Java code or in VM are stopped by the Safepoint. However, 3960 // daemon threads executing native code are still running. But they 3961 // will be stopped at native=>Java/VM barriers. Note that we can't 3962 // simply kill or suspend them, as it is inherently deadlock-prone. 3963 3964#ifndef PRODUCT 3965 // disable function tracing at JNI/JVM barriers 3966 TraceJNICalls = false; 3967 TraceJVMCalls = false; 3968 TraceRuntimeCalls = false; 3969#endif 3970 3971 VM_Exit::set_vm_exited(); 3972 3973 notify_vm_shutdown(); 3974 3975 delete thread; 3976 3977 // exit_globals() will delete tty 3978 exit_globals(); 3979 3980 return true; 3981} 3982 3983 3984jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 3985 if (version == JNI_VERSION_1_1) return JNI_TRUE; 3986 return is_supported_jni_version(version); 3987} 3988 3989 3990jboolean Threads::is_supported_jni_version(jint version) { 3991 if (version == JNI_VERSION_1_2) return JNI_TRUE; 3992 if (version == JNI_VERSION_1_4) return JNI_TRUE; 3993 if (version == JNI_VERSION_1_6) return JNI_TRUE; 3994 return JNI_FALSE; 3995} 3996 3997 3998void Threads::add(JavaThread* p, bool force_daemon) { 3999 // The threads lock must be owned at this point 4000 assert_locked_or_safepoint(Threads_lock); 4001 4002 // See the comment for this method in thread.hpp for its purpose and 4003 // why it is called here. 4004 p->initialize_queues(); 4005 p->set_next(_thread_list); 4006 _thread_list = p; 4007 _number_of_threads++; 4008 oop threadObj = p->threadObj(); 4009 bool daemon = true; 4010 // Bootstrapping problem: threadObj can be null for initial 4011 // JavaThread (or for threads attached via JNI) 4012 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4013 _number_of_non_daemon_threads++; 4014 daemon = false; 4015 } 4016 4017 p->set_safepoint_visible(true); 4018 4019 ThreadService::add_thread(p, daemon); 4020 4021 // Possible GC point. 4022 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4023} 4024 4025void Threads::remove(JavaThread* p) { 4026 // Extra scope needed for Thread_lock, so we can check 4027 // that we do not remove thread without safepoint code notice 4028 { MutexLocker ml(Threads_lock); 4029 4030 assert(includes(p), "p must be present"); 4031 4032 JavaThread* current = _thread_list; 4033 JavaThread* prev = NULL; 4034 4035 while (current != p) { 4036 prev = current; 4037 current = current->next(); 4038 } 4039 4040 if (prev) { 4041 prev->set_next(current->next()); 4042 } else { 4043 _thread_list = p->next(); 4044 } 4045 _number_of_threads--; 4046 oop threadObj = p->threadObj(); 4047 bool daemon = true; 4048 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4049 _number_of_non_daemon_threads--; 4050 daemon = false; 4051 4052 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4053 // on destroy_vm will wake up. 4054 if (number_of_non_daemon_threads() == 1) 4055 Threads_lock->notify_all(); 4056 } 4057 ThreadService::remove_thread(p, daemon); 4058 4059 // Make sure that safepoint code disregard this thread. This is needed since 4060 // the thread might mess around with locks after this point. This can cause it 4061 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4062 // of this thread since it is removed from the queue. 4063 p->set_terminated_value(); 4064 4065 // Now, this thread is not visible to safepoint 4066 p->set_safepoint_visible(false); 4067 4068 } // unlock Threads_lock 4069 4070 // Since Events::log uses a lock, we grab it outside the Threads_lock 4071 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4072} 4073 4074// Threads_lock must be held when this is called (or must be called during a safepoint) 4075bool Threads::includes(JavaThread* p) { 4076 assert(Threads_lock->is_locked(), "sanity check"); 4077 ALL_JAVA_THREADS(q) { 4078 if (q == p ) { 4079 return true; 4080 } 4081 } 4082 return false; 4083} 4084 4085// Operations on the Threads list for GC. These are not explicitly locked, 4086// but the garbage collector must provide a safe context for them to run. 4087// In particular, these things should never be called when the Threads_lock 4088// is held by some other thread. (Note: the Safepoint abstraction also 4089// uses the Threads_lock to gurantee this property. It also makes sure that 4090// all threads gets blocked when exiting or starting). 4091 4092void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) { 4093 ALL_JAVA_THREADS(p) { 4094 p->oops_do(f, cf); 4095 } 4096 VMThread::vm_thread()->oops_do(f, cf); 4097} 4098 4099void Threads::possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf) { 4100 // Introduce a mechanism allowing parallel threads to claim threads as 4101 // root groups. Overhead should be small enough to use all the time, 4102 // even in sequential code. 4103 SharedHeap* sh = SharedHeap::heap(); 4104 // Cannot yet substitute active_workers for n_par_threads 4105 // because of G1CollectedHeap::verify() use of 4106 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4107 // turn off parallelism in process_strong_roots while active_workers 4108 // is being used for parallelism elsewhere. 4109 bool is_par = sh->n_par_threads() > 0; 4110 assert(!is_par || 4111 (SharedHeap::heap()->n_par_threads() == 4112 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4113 int cp = SharedHeap::heap()->strong_roots_parity(); 4114 ALL_JAVA_THREADS(p) { 4115 if (p->claim_oops_do(is_par, cp)) { 4116 p->oops_do(f, cf); 4117 } 4118 } 4119 VMThread* vmt = VMThread::vm_thread(); 4120 if (vmt->claim_oops_do(is_par, cp)) { 4121 vmt->oops_do(f, cf); 4122 } 4123} 4124 4125#ifndef SERIALGC 4126// Used by ParallelScavenge 4127void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4128 ALL_JAVA_THREADS(p) { 4129 q->enqueue(new ThreadRootsTask(p)); 4130 } 4131 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4132} 4133 4134// Used by Parallel Old 4135void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4136 ALL_JAVA_THREADS(p) { 4137 q->enqueue(new ThreadRootsMarkingTask(p)); 4138 } 4139 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4140} 4141#endif // SERIALGC 4142 4143void Threads::nmethods_do(CodeBlobClosure* cf) { 4144 ALL_JAVA_THREADS(p) { 4145 p->nmethods_do(cf); 4146 } 4147 VMThread::vm_thread()->nmethods_do(cf); 4148} 4149 4150void Threads::metadata_do(void f(Metadata*)) { 4151 ALL_JAVA_THREADS(p) { 4152 p->metadata_do(f); 4153 } 4154} 4155 4156void Threads::gc_epilogue() { 4157 ALL_JAVA_THREADS(p) { 4158 p->gc_epilogue(); 4159 } 4160} 4161 4162void Threads::gc_prologue() { 4163 ALL_JAVA_THREADS(p) { 4164 p->gc_prologue(); 4165 } 4166} 4167 4168void Threads::deoptimized_wrt_marked_nmethods() { 4169 ALL_JAVA_THREADS(p) { 4170 p->deoptimized_wrt_marked_nmethods(); 4171 } 4172} 4173 4174 4175// Get count Java threads that are waiting to enter the specified monitor. 4176GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4177 address monitor, bool doLock) { 4178 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4179 "must grab Threads_lock or be at safepoint"); 4180 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4181 4182 int i = 0; 4183 { 4184 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4185 ALL_JAVA_THREADS(p) { 4186 if (p->is_Compiler_thread()) continue; 4187 4188 address pending = (address)p->current_pending_monitor(); 4189 if (pending == monitor) { // found a match 4190 if (i < count) result->append(p); // save the first count matches 4191 i++; 4192 } 4193 } 4194 } 4195 return result; 4196} 4197 4198 4199JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4200 assert(doLock || 4201 Threads_lock->owned_by_self() || 4202 SafepointSynchronize::is_at_safepoint(), 4203 "must grab Threads_lock or be at safepoint"); 4204 4205 // NULL owner means not locked so we can skip the search 4206 if (owner == NULL) return NULL; 4207 4208 { 4209 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4210 ALL_JAVA_THREADS(p) { 4211 // first, see if owner is the address of a Java thread 4212 if (owner == (address)p) return p; 4213 } 4214 } 4215 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled"); 4216 if (UseHeavyMonitors) return NULL; 4217 4218 // 4219 // If we didn't find a matching Java thread and we didn't force use of 4220 // heavyweight monitors, then the owner is the stack address of the 4221 // Lock Word in the owning Java thread's stack. 4222 // 4223 JavaThread* the_owner = NULL; 4224 { 4225 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4226 ALL_JAVA_THREADS(q) { 4227 if (q->is_lock_owned(owner)) { 4228 the_owner = q; 4229 break; 4230 } 4231 } 4232 } 4233 assert(the_owner != NULL, "Did not find owning Java thread for lock word address"); 4234 return the_owner; 4235} 4236 4237// Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4238void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4239 char buf[32]; 4240 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4241 4242 st->print_cr("Full thread dump %s (%s %s):", 4243 Abstract_VM_Version::vm_name(), 4244 Abstract_VM_Version::vm_release(), 4245 Abstract_VM_Version::vm_info_string() 4246 ); 4247 st->cr(); 4248 4249#ifndef SERIALGC 4250 // Dump concurrent locks 4251 ConcurrentLocksDump concurrent_locks; 4252 if (print_concurrent_locks) { 4253 concurrent_locks.dump_at_safepoint(); 4254 } 4255#endif // SERIALGC 4256 4257 ALL_JAVA_THREADS(p) { 4258 ResourceMark rm; 4259 p->print_on(st); 4260 if (print_stacks) { 4261 if (internal_format) { 4262 p->trace_stack(); 4263 } else { 4264 p->print_stack_on(st); 4265 } 4266 } 4267 st->cr(); 4268#ifndef SERIALGC 4269 if (print_concurrent_locks) { 4270 concurrent_locks.print_locks_on(p, st); 4271 } 4272#endif // SERIALGC 4273 } 4274 4275 VMThread::vm_thread()->print_on(st); 4276 st->cr(); 4277 Universe::heap()->print_gc_threads_on(st); 4278 WatcherThread* wt = WatcherThread::watcher_thread(); 4279 if (wt != NULL) wt->print_on(st); 4280 st->cr(); 4281 CompileBroker::print_compiler_threads_on(st); 4282 st->flush(); 4283} 4284 4285// Threads::print_on_error() is called by fatal error handler. It's possible 4286// that VM is not at safepoint and/or current thread is inside signal handler. 4287// Don't print stack trace, as the stack may not be walkable. Don't allocate 4288// memory (even in resource area), it might deadlock the error handler. 4289void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4290 bool found_current = false; 4291 st->print_cr("Java Threads: ( => current thread )"); 4292 ALL_JAVA_THREADS(thread) { 4293 bool is_current = (current == thread); 4294 found_current = found_current || is_current; 4295 4296 st->print("%s", is_current ? "=>" : " "); 4297 4298 st->print(PTR_FORMAT, thread); 4299 st->print(" "); 4300 thread->print_on_error(st, buf, buflen); 4301 st->cr(); 4302 } 4303 st->cr(); 4304 4305 st->print_cr("Other Threads:"); 4306 if (VMThread::vm_thread()) { 4307 bool is_current = (current == VMThread::vm_thread()); 4308 found_current = found_current || is_current; 4309 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4310 4311 st->print(PTR_FORMAT, VMThread::vm_thread()); 4312 st->print(" "); 4313 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4314 st->cr(); 4315 } 4316 WatcherThread* wt = WatcherThread::watcher_thread(); 4317 if (wt != NULL) { 4318 bool is_current = (current == wt); 4319 found_current = found_current || is_current; 4320 st->print("%s", is_current ? "=>" : " "); 4321 4322 st->print(PTR_FORMAT, wt); 4323 st->print(" "); 4324 wt->print_on_error(st, buf, buflen); 4325 st->cr(); 4326 } 4327 if (!found_current) { 4328 st->cr(); 4329 st->print("=>" PTR_FORMAT " (exited) ", current); 4330 current->print_on_error(st, buf, buflen); 4331 st->cr(); 4332 } 4333} 4334 4335// Internal SpinLock and Mutex 4336// Based on ParkEvent 4337 4338// Ad-hoc mutual exclusion primitives: SpinLock and Mux 4339// 4340// We employ SpinLocks _only for low-contention, fixed-length 4341// short-duration critical sections where we're concerned 4342// about native mutex_t or HotSpot Mutex:: latency. 4343// The mux construct provides a spin-then-block mutual exclusion 4344// mechanism. 4345// 4346// Testing has shown that contention on the ListLock guarding gFreeList 4347// is common. If we implement ListLock as a simple SpinLock it's common 4348// for the JVM to devolve to yielding with little progress. This is true 4349// despite the fact that the critical sections protected by ListLock are 4350// extremely short. 4351// 4352// TODO-FIXME: ListLock should be of type SpinLock. 4353// We should make this a 1st-class type, integrated into the lock 4354// hierarchy as leaf-locks. Critically, the SpinLock structure 4355// should have sufficient padding to avoid false-sharing and excessive 4356// cache-coherency traffic. 4357 4358 4359typedef volatile int SpinLockT ; 4360 4361void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4362 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4363 return ; // normal fast-path return 4364 } 4365 4366 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4367 TEVENT (SpinAcquire - ctx) ; 4368 int ctr = 0 ; 4369 int Yields = 0 ; 4370 for (;;) { 4371 while (*adr != 0) { 4372 ++ctr ; 4373 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4374 if (Yields > 5) { 4375 // Consider using a simple NakedSleep() instead. 4376 // Then SpinAcquire could be called by non-JVM threads 4377 Thread::current()->_ParkEvent->park(1) ; 4378 } else { 4379 os::NakedYield() ; 4380 ++Yields ; 4381 } 4382 } else { 4383 SpinPause() ; 4384 } 4385 } 4386 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4387 } 4388} 4389 4390void Thread::SpinRelease (volatile int * adr) { 4391 assert (*adr != 0, "invariant") ; 4392 OrderAccess::fence() ; // guarantee at least release consistency. 4393 // Roach-motel semantics. 4394 // It's safe if subsequent LDs and STs float "up" into the critical section, 4395 // but prior LDs and STs within the critical section can't be allowed 4396 // to reorder or float past the ST that releases the lock. 4397 *adr = 0 ; 4398} 4399 4400// muxAcquire and muxRelease: 4401// 4402// * muxAcquire and muxRelease support a single-word lock-word construct. 4403// The LSB of the word is set IFF the lock is held. 4404// The remainder of the word points to the head of a singly-linked list 4405// of threads blocked on the lock. 4406// 4407// * The current implementation of muxAcquire-muxRelease uses its own 4408// dedicated Thread._MuxEvent instance. If we're interested in 4409// minimizing the peak number of extant ParkEvent instances then 4410// we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4411// as certain invariants were satisfied. Specifically, care would need 4412// to be taken with regards to consuming unpark() "permits". 4413// A safe rule of thumb is that a thread would never call muxAcquire() 4414// if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4415// park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4416// consume an unpark() permit intended for monitorenter, for instance. 4417// One way around this would be to widen the restricted-range semaphore 4418// implemented in park(). Another alternative would be to provide 4419// multiple instances of the PlatformEvent() for each thread. One 4420// instance would be dedicated to muxAcquire-muxRelease, for instance. 4421// 4422// * Usage: 4423// -- Only as leaf locks 4424// -- for short-term locking only as muxAcquire does not perform 4425// thread state transitions. 4426// 4427// Alternatives: 4428// * We could implement muxAcquire and muxRelease with MCS or CLH locks 4429// but with parking or spin-then-park instead of pure spinning. 4430// * Use Taura-Oyama-Yonenzawa locks. 4431// * It's possible to construct a 1-0 lock if we encode the lockword as 4432// (List,LockByte). Acquire will CAS the full lockword while Release 4433// will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4434// acquiring threads use timers (ParkTimed) to detect and recover from 4435// the stranding window. Thread/Node structures must be aligned on 256-byte 4436// boundaries by using placement-new. 4437// * Augment MCS with advisory back-link fields maintained with CAS(). 4438// Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4439// The validity of the backlinks must be ratified before we trust the value. 4440// If the backlinks are invalid the exiting thread must back-track through the 4441// the forward links, which are always trustworthy. 4442// * Add a successor indication. The LockWord is currently encoded as 4443// (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4444// to provide the usual futile-wakeup optimization. 4445// See RTStt for details. 4446// * Consider schedctl.sc_nopreempt to cover the critical section. 4447// 4448 4449 4450typedef volatile intptr_t MutexT ; // Mux Lock-word 4451enum MuxBits { LOCKBIT = 1 } ; 4452 4453void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4454 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4455 if (w == 0) return ; 4456 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4457 return ; 4458 } 4459 4460 TEVENT (muxAcquire - Contention) ; 4461 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4462 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4463 for (;;) { 4464 int its = (os::is_MP() ? 100 : 0) + 1 ; 4465 4466 // Optional spin phase: spin-then-park strategy 4467 while (--its >= 0) { 4468 w = *Lock ; 4469 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4470 return ; 4471 } 4472 } 4473 4474 Self->reset() ; 4475 Self->OnList = intptr_t(Lock) ; 4476 // The following fence() isn't _strictly necessary as the subsequent 4477 // CAS() both serializes execution and ratifies the fetched *Lock value. 4478 OrderAccess::fence(); 4479 for (;;) { 4480 w = *Lock ; 4481 if ((w & LOCKBIT) == 0) { 4482 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4483 Self->OnList = 0 ; // hygiene - allows stronger asserts 4484 return ; 4485 } 4486 continue ; // Interference -- *Lock changed -- Just retry 4487 } 4488 assert (w & LOCKBIT, "invariant") ; 4489 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4490 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4491 } 4492 4493 while (Self->OnList != 0) { 4494 Self->park() ; 4495 } 4496 } 4497} 4498 4499void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4500 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4501 if (w == 0) return ; 4502 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4503 return ; 4504 } 4505 4506 TEVENT (muxAcquire - Contention) ; 4507 ParkEvent * ReleaseAfter = NULL ; 4508 if (ev == NULL) { 4509 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4510 } 4511 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4512 for (;;) { 4513 guarantee (ev->OnList == 0, "invariant") ; 4514 int its = (os::is_MP() ? 100 : 0) + 1 ; 4515 4516 // Optional spin phase: spin-then-park strategy 4517 while (--its >= 0) { 4518 w = *Lock ; 4519 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4520 if (ReleaseAfter != NULL) { 4521 ParkEvent::Release (ReleaseAfter) ; 4522 } 4523 return ; 4524 } 4525 } 4526 4527 ev->reset() ; 4528 ev->OnList = intptr_t(Lock) ; 4529 // The following fence() isn't _strictly necessary as the subsequent 4530 // CAS() both serializes execution and ratifies the fetched *Lock value. 4531 OrderAccess::fence(); 4532 for (;;) { 4533 w = *Lock ; 4534 if ((w & LOCKBIT) == 0) { 4535 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4536 ev->OnList = 0 ; 4537 // We call ::Release while holding the outer lock, thus 4538 // artificially lengthening the critical section. 4539 // Consider deferring the ::Release() until the subsequent unlock(), 4540 // after we've dropped the outer lock. 4541 if (ReleaseAfter != NULL) { 4542 ParkEvent::Release (ReleaseAfter) ; 4543 } 4544 return ; 4545 } 4546 continue ; // Interference -- *Lock changed -- Just retry 4547 } 4548 assert (w & LOCKBIT, "invariant") ; 4549 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4550 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4551 } 4552 4553 while (ev->OnList != 0) { 4554 ev->park() ; 4555 } 4556 } 4557} 4558 4559// Release() must extract a successor from the list and then wake that thread. 4560// It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4561// similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4562// Release() would : 4563// (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4564// (B) Extract a successor from the private list "in-hand" 4565// (C) attempt to CAS() the residual back into *Lock over null. 4566// If there were any newly arrived threads and the CAS() would fail. 4567// In that case Release() would detach the RATs, re-merge the list in-hand 4568// with the RATs and repeat as needed. Alternately, Release() might 4569// detach and extract a successor, but then pass the residual list to the wakee. 4570// The wakee would be responsible for reattaching and remerging before it 4571// competed for the lock. 4572// 4573// Both "pop" and DMR are immune from ABA corruption -- there can be 4574// multiple concurrent pushers, but only one popper or detacher. 4575// This implementation pops from the head of the list. This is unfair, 4576// but tends to provide excellent throughput as hot threads remain hot. 4577// (We wake recently run threads first). 4578 4579void Thread::muxRelease (volatile intptr_t * Lock) { 4580 for (;;) { 4581 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4582 assert (w & LOCKBIT, "invariant") ; 4583 if (w == LOCKBIT) return ; 4584 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4585 assert (List != NULL, "invariant") ; 4586 assert (List->OnList == intptr_t(Lock), "invariant") ; 4587 ParkEvent * nxt = List->ListNext ; 4588 4589 // The following CAS() releases the lock and pops the head element. 4590 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4591 continue ; 4592 } 4593 List->OnList = 0 ; 4594 OrderAccess::fence() ; 4595 List->unpark () ; 4596 return ; 4597 } 4598} 4599 4600 4601void Threads::verify() { 4602 ALL_JAVA_THREADS(p) { 4603 p->verify(); 4604 } 4605 VMThread* thread = VMThread::vm_thread(); 4606 if (thread != NULL) thread->verify(); 4607} 4608