thread.cpp revision 5959:438e13354adf
1/* 2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "precompiled.hpp" 26#include "classfile/classLoader.hpp" 27#include "classfile/javaClasses.hpp" 28#include "classfile/systemDictionary.hpp" 29#include "classfile/vmSymbols.hpp" 30#include "code/scopeDesc.hpp" 31#include "compiler/compileBroker.hpp" 32#include "interpreter/interpreter.hpp" 33#include "interpreter/linkResolver.hpp" 34#include "interpreter/oopMapCache.hpp" 35#include "jvmtifiles/jvmtiEnv.hpp" 36#include "memory/gcLocker.inline.hpp" 37#include "memory/metaspaceShared.hpp" 38#include "memory/oopFactory.hpp" 39#include "memory/universe.inline.hpp" 40#include "oops/instanceKlass.hpp" 41#include "oops/objArrayOop.hpp" 42#include "oops/oop.inline.hpp" 43#include "oops/symbol.hpp" 44#include "prims/jvm_misc.hpp" 45#include "prims/jvmtiExport.hpp" 46#include "prims/jvmtiThreadState.hpp" 47#include "prims/privilegedStack.hpp" 48#include "runtime/arguments.hpp" 49#include "runtime/biasedLocking.hpp" 50#include "runtime/deoptimization.hpp" 51#include "runtime/fprofiler.hpp" 52#include "runtime/frame.inline.hpp" 53#include "runtime/init.hpp" 54#include "runtime/interfaceSupport.hpp" 55#include "runtime/java.hpp" 56#include "runtime/javaCalls.hpp" 57#include "runtime/jniPeriodicChecker.hpp" 58#include "runtime/memprofiler.hpp" 59#include "runtime/mutexLocker.hpp" 60#include "runtime/objectMonitor.hpp" 61#include "runtime/osThread.hpp" 62#include "runtime/safepoint.hpp" 63#include "runtime/sharedRuntime.hpp" 64#include "runtime/statSampler.hpp" 65#include "runtime/stubRoutines.hpp" 66#include "runtime/task.hpp" 67#include "runtime/thread.inline.hpp" 68#include "runtime/threadCritical.hpp" 69#include "runtime/threadLocalStorage.hpp" 70#include "runtime/vframe.hpp" 71#include "runtime/vframeArray.hpp" 72#include "runtime/vframe_hp.hpp" 73#include "runtime/vmThread.hpp" 74#include "runtime/vm_operations.hpp" 75#include "services/attachListener.hpp" 76#include "services/management.hpp" 77#include "services/memTracker.hpp" 78#include "services/threadService.hpp" 79#include "trace/tracing.hpp" 80#include "trace/traceMacros.hpp" 81#include "utilities/defaultStream.hpp" 82#include "utilities/dtrace.hpp" 83#include "utilities/events.hpp" 84#include "utilities/preserveException.hpp" 85#include "utilities/macros.hpp" 86#ifdef TARGET_OS_FAMILY_linux 87# include "os_linux.inline.hpp" 88#endif 89#ifdef TARGET_OS_FAMILY_solaris 90# include "os_solaris.inline.hpp" 91#endif 92#ifdef TARGET_OS_FAMILY_windows 93# include "os_windows.inline.hpp" 94#endif 95#ifdef TARGET_OS_FAMILY_bsd 96# include "os_bsd.inline.hpp" 97#endif 98#if INCLUDE_ALL_GCS 99#include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 100#include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 101#include "gc_implementation/parallelScavenge/pcTasks.hpp" 102#endif // INCLUDE_ALL_GCS 103#ifdef COMPILER1 104#include "c1/c1_Compiler.hpp" 105#endif 106#ifdef COMPILER2 107#include "opto/c2compiler.hpp" 108#include "opto/idealGraphPrinter.hpp" 109#endif 110 111#ifdef DTRACE_ENABLED 112 113// Only bother with this argument setup if dtrace is available 114 115#ifndef USDT2 116HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 117HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 118HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 119 intptr_t, intptr_t, bool); 120HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 121 intptr_t, intptr_t, bool); 122 123#define DTRACE_THREAD_PROBE(probe, javathread) \ 124 { \ 125 ResourceMark rm(this); \ 126 int len = 0; \ 127 const char* name = (javathread)->get_thread_name(); \ 128 len = strlen(name); \ 129 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 130 name, len, \ 131 java_lang_Thread::thread_id((javathread)->threadObj()), \ 132 (javathread)->osthread()->thread_id(), \ 133 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 134 } 135 136#else /* USDT2 */ 137 138#define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START 139#define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP 140 141#define DTRACE_THREAD_PROBE(probe, javathread) \ 142 { \ 143 ResourceMark rm(this); \ 144 int len = 0; \ 145 const char* name = (javathread)->get_thread_name(); \ 146 len = strlen(name); \ 147 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 148 (char *) name, len, \ 149 java_lang_Thread::thread_id((javathread)->threadObj()), \ 150 (uintptr_t) (javathread)->osthread()->thread_id(), \ 151 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 152 } 153 154#endif /* USDT2 */ 155 156#else // ndef DTRACE_ENABLED 157 158#define DTRACE_THREAD_PROBE(probe, javathread) 159 160#endif // ndef DTRACE_ENABLED 161 162 163// Class hierarchy 164// - Thread 165// - VMThread 166// - WatcherThread 167// - ConcurrentMarkSweepThread 168// - JavaThread 169// - CompilerThread 170 171// ======= Thread ======== 172// Support for forcing alignment of thread objects for biased locking 173void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 174 if (UseBiasedLocking) { 175 const int alignment = markOopDesc::biased_lock_alignment; 176 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 177 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 178 : AllocateHeap(aligned_size, flags, CURRENT_PC, 179 AllocFailStrategy::RETURN_NULL); 180 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 181 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 182 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 183 "JavaThread alignment code overflowed allocated storage"); 184 if (TraceBiasedLocking) { 185 if (aligned_addr != real_malloc_addr) 186 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 187 real_malloc_addr, aligned_addr); 188 } 189 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 190 return aligned_addr; 191 } else { 192 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 193 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 194 } 195} 196 197void Thread::operator delete(void* p) { 198 if (UseBiasedLocking) { 199 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 200 FreeHeap(real_malloc_addr, mtThread); 201 } else { 202 FreeHeap(p, mtThread); 203 } 204} 205 206 207// Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 208// JavaThread 209 210 211Thread::Thread() { 212 // stack and get_thread 213 set_stack_base(NULL); 214 set_stack_size(0); 215 set_self_raw_id(0); 216 set_lgrp_id(-1); 217 218 // allocated data structures 219 set_osthread(NULL); 220 set_resource_area(new (mtThread)ResourceArea()); 221 set_handle_area(new (mtThread) HandleArea(NULL)); 222 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 223 set_active_handles(NULL); 224 set_free_handle_block(NULL); 225 set_last_handle_mark(NULL); 226 227 // This initial value ==> never claimed. 228 _oops_do_parity = 0; 229 230 // the handle mark links itself to last_handle_mark 231 new HandleMark(this); 232 233 // plain initialization 234 debug_only(_owned_locks = NULL;) 235 debug_only(_allow_allocation_count = 0;) 236 NOT_PRODUCT(_allow_safepoint_count = 0;) 237 NOT_PRODUCT(_skip_gcalot = false;) 238 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;) 239 _jvmti_env_iteration_count = 0; 240 set_allocated_bytes(0); 241 _vm_operation_started_count = 0; 242 _vm_operation_completed_count = 0; 243 _current_pending_monitor = NULL; 244 _current_pending_monitor_is_from_java = true; 245 _current_waiting_monitor = NULL; 246 _num_nested_signal = 0; 247 omFreeList = NULL ; 248 omFreeCount = 0 ; 249 omFreeProvision = 32 ; 250 omInUseList = NULL ; 251 omInUseCount = 0 ; 252 253#ifdef ASSERT 254 _visited_for_critical_count = false; 255#endif 256 257 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true); 258 _suspend_flags = 0; 259 260 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 261 _hashStateX = os::random() ; 262 _hashStateY = 842502087 ; 263 _hashStateZ = 0x8767 ; // (int)(3579807591LL & 0xffff) ; 264 _hashStateW = 273326509 ; 265 266 _OnTrap = 0 ; 267 _schedctl = NULL ; 268 _Stalled = 0 ; 269 _TypeTag = 0x2BAD ; 270 271 // Many of the following fields are effectively final - immutable 272 // Note that nascent threads can't use the Native Monitor-Mutex 273 // construct until the _MutexEvent is initialized ... 274 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 275 // we might instead use a stack of ParkEvents that we could provision on-demand. 276 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 277 // and ::Release() 278 _ParkEvent = ParkEvent::Allocate (this) ; 279 _SleepEvent = ParkEvent::Allocate (this) ; 280 _MutexEvent = ParkEvent::Allocate (this) ; 281 _MuxEvent = ParkEvent::Allocate (this) ; 282 283#ifdef CHECK_UNHANDLED_OOPS 284 if (CheckUnhandledOops) { 285 _unhandled_oops = new UnhandledOops(this); 286 } 287#endif // CHECK_UNHANDLED_OOPS 288#ifdef ASSERT 289 if (UseBiasedLocking) { 290 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 291 assert(this == _real_malloc_address || 292 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 293 "bug in forced alignment of thread objects"); 294 } 295#endif /* ASSERT */ 296} 297 298void Thread::initialize_thread_local_storage() { 299 // Note: Make sure this method only calls 300 // non-blocking operations. Otherwise, it might not work 301 // with the thread-startup/safepoint interaction. 302 303 // During Java thread startup, safepoint code should allow this 304 // method to complete because it may need to allocate memory to 305 // store information for the new thread. 306 307 // initialize structure dependent on thread local storage 308 ThreadLocalStorage::set_thread(this); 309} 310 311void Thread::record_stack_base_and_size() { 312 set_stack_base(os::current_stack_base()); 313 set_stack_size(os::current_stack_size()); 314 if (is_Java_thread()) { 315 ((JavaThread*) this)->set_stack_overflow_limit(); 316 } 317 // CR 7190089: on Solaris, primordial thread's stack is adjusted 318 // in initialize_thread(). Without the adjustment, stack size is 319 // incorrect if stack is set to unlimited (ulimit -s unlimited). 320 // So far, only Solaris has real implementation of initialize_thread(). 321 // 322 // set up any platform-specific state. 323 os::initialize_thread(this); 324 325#if INCLUDE_NMT 326 // record thread's native stack, stack grows downward 327 address stack_low_addr = stack_base() - stack_size(); 328 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 329 CURRENT_PC); 330#endif // INCLUDE_NMT 331} 332 333 334Thread::~Thread() { 335 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 336 ObjectSynchronizer::omFlush (this) ; 337 338 // stack_base can be NULL if the thread is never started or exited before 339 // record_stack_base_and_size called. Although, we would like to ensure 340 // that all started threads do call record_stack_base_and_size(), there is 341 // not proper way to enforce that. 342#if INCLUDE_NMT 343 if (_stack_base != NULL) { 344 address low_stack_addr = stack_base() - stack_size(); 345 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); 346#ifdef ASSERT 347 set_stack_base(NULL); 348#endif 349 } 350#endif // INCLUDE_NMT 351 352 // deallocate data structures 353 delete resource_area(); 354 // since the handle marks are using the handle area, we have to deallocated the root 355 // handle mark before deallocating the thread's handle area, 356 assert(last_handle_mark() != NULL, "check we have an element"); 357 delete last_handle_mark(); 358 assert(last_handle_mark() == NULL, "check we have reached the end"); 359 360 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 361 // We NULL out the fields for good hygiene. 362 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 363 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 364 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 365 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 366 367 delete handle_area(); 368 delete metadata_handles(); 369 370 // osthread() can be NULL, if creation of thread failed. 371 if (osthread() != NULL) os::free_thread(osthread()); 372 373 delete _SR_lock; 374 375 // clear thread local storage if the Thread is deleting itself 376 if (this == Thread::current()) { 377 ThreadLocalStorage::set_thread(NULL); 378 } else { 379 // In the case where we're not the current thread, invalidate all the 380 // caches in case some code tries to get the current thread or the 381 // thread that was destroyed, and gets stale information. 382 ThreadLocalStorage::invalidate_all(); 383 } 384 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 385} 386 387// NOTE: dummy function for assertion purpose. 388void Thread::run() { 389 ShouldNotReachHere(); 390} 391 392#ifdef ASSERT 393// Private method to check for dangling thread pointer 394void check_for_dangling_thread_pointer(Thread *thread) { 395 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 396 "possibility of dangling Thread pointer"); 397} 398#endif 399 400 401#ifndef PRODUCT 402// Tracing method for basic thread operations 403void Thread::trace(const char* msg, const Thread* const thread) { 404 if (!TraceThreadEvents) return; 405 ResourceMark rm; 406 ThreadCritical tc; 407 const char *name = "non-Java thread"; 408 int prio = -1; 409 if (thread->is_Java_thread() 410 && !thread->is_Compiler_thread()) { 411 // The Threads_lock must be held to get information about 412 // this thread but may not be in some situations when 413 // tracing thread events. 414 bool release_Threads_lock = false; 415 if (!Threads_lock->owned_by_self()) { 416 Threads_lock->lock(); 417 release_Threads_lock = true; 418 } 419 JavaThread* jt = (JavaThread *)thread; 420 name = (char *)jt->get_thread_name(); 421 oop thread_oop = jt->threadObj(); 422 if (thread_oop != NULL) { 423 prio = java_lang_Thread::priority(thread_oop); 424 } 425 if (release_Threads_lock) { 426 Threads_lock->unlock(); 427 } 428 } 429 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 430} 431#endif 432 433 434ThreadPriority Thread::get_priority(const Thread* const thread) { 435 trace("get priority", thread); 436 ThreadPriority priority; 437 // Can return an error! 438 (void)os::get_priority(thread, priority); 439 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 440 return priority; 441} 442 443void Thread::set_priority(Thread* thread, ThreadPriority priority) { 444 trace("set priority", thread); 445 debug_only(check_for_dangling_thread_pointer(thread);) 446 // Can return an error! 447 (void)os::set_priority(thread, priority); 448} 449 450 451void Thread::start(Thread* thread) { 452 trace("start", thread); 453 // Start is different from resume in that its safety is guaranteed by context or 454 // being called from a Java method synchronized on the Thread object. 455 if (!DisableStartThread) { 456 if (thread->is_Java_thread()) { 457 // Initialize the thread state to RUNNABLE before starting this thread. 458 // Can not set it after the thread started because we do not know the 459 // exact thread state at that time. It could be in MONITOR_WAIT or 460 // in SLEEPING or some other state. 461 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 462 java_lang_Thread::RUNNABLE); 463 } 464 os::start_thread(thread); 465 } 466} 467 468// Enqueue a VM_Operation to do the job for us - sometime later 469void Thread::send_async_exception(oop java_thread, oop java_throwable) { 470 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 471 VMThread::execute(vm_stop); 472} 473 474 475// 476// Check if an external suspend request has completed (or has been 477// cancelled). Returns true if the thread is externally suspended and 478// false otherwise. 479// 480// The bits parameter returns information about the code path through 481// the routine. Useful for debugging: 482// 483// set in is_ext_suspend_completed(): 484// 0x00000001 - routine was entered 485// 0x00000010 - routine return false at end 486// 0x00000100 - thread exited (return false) 487// 0x00000200 - suspend request cancelled (return false) 488// 0x00000400 - thread suspended (return true) 489// 0x00001000 - thread is in a suspend equivalent state (return true) 490// 0x00002000 - thread is native and walkable (return true) 491// 0x00004000 - thread is native_trans and walkable (needed retry) 492// 493// set in wait_for_ext_suspend_completion(): 494// 0x00010000 - routine was entered 495// 0x00020000 - suspend request cancelled before loop (return false) 496// 0x00040000 - thread suspended before loop (return true) 497// 0x00080000 - suspend request cancelled in loop (return false) 498// 0x00100000 - thread suspended in loop (return true) 499// 0x00200000 - suspend not completed during retry loop (return false) 500// 501 502// Helper class for tracing suspend wait debug bits. 503// 504// 0x00000100 indicates that the target thread exited before it could 505// self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 506// 0x00080000 each indicate a cancelled suspend request so they don't 507// count as wait failures either. 508#define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 509 510class TraceSuspendDebugBits : public StackObj { 511 private: 512 JavaThread * jt; 513 bool is_wait; 514 bool called_by_wait; // meaningful when !is_wait 515 uint32_t * bits; 516 517 public: 518 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 519 uint32_t *_bits) { 520 jt = _jt; 521 is_wait = _is_wait; 522 called_by_wait = _called_by_wait; 523 bits = _bits; 524 } 525 526 ~TraceSuspendDebugBits() { 527 if (!is_wait) { 528#if 1 529 // By default, don't trace bits for is_ext_suspend_completed() calls. 530 // That trace is very chatty. 531 return; 532#else 533 if (!called_by_wait) { 534 // If tracing for is_ext_suspend_completed() is enabled, then only 535 // trace calls to it from wait_for_ext_suspend_completion() 536 return; 537 } 538#endif 539 } 540 541 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 542 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 543 MutexLocker ml(Threads_lock); // needed for get_thread_name() 544 ResourceMark rm; 545 546 tty->print_cr( 547 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 548 jt->get_thread_name(), *bits); 549 550 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 551 } 552 } 553 } 554}; 555#undef DEBUG_FALSE_BITS 556 557 558bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 559 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 560 561 bool did_trans_retry = false; // only do thread_in_native_trans retry once 562 bool do_trans_retry; // flag to force the retry 563 564 *bits |= 0x00000001; 565 566 do { 567 do_trans_retry = false; 568 569 if (is_exiting()) { 570 // Thread is in the process of exiting. This is always checked 571 // first to reduce the risk of dereferencing a freed JavaThread. 572 *bits |= 0x00000100; 573 return false; 574 } 575 576 if (!is_external_suspend()) { 577 // Suspend request is cancelled. This is always checked before 578 // is_ext_suspended() to reduce the risk of a rogue resume 579 // confusing the thread that made the suspend request. 580 *bits |= 0x00000200; 581 return false; 582 } 583 584 if (is_ext_suspended()) { 585 // thread is suspended 586 *bits |= 0x00000400; 587 return true; 588 } 589 590 // Now that we no longer do hard suspends of threads running 591 // native code, the target thread can be changing thread state 592 // while we are in this routine: 593 // 594 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 595 // 596 // We save a copy of the thread state as observed at this moment 597 // and make our decision about suspend completeness based on the 598 // copy. This closes the race where the thread state is seen as 599 // _thread_in_native_trans in the if-thread_blocked check, but is 600 // seen as _thread_blocked in if-thread_in_native_trans check. 601 JavaThreadState save_state = thread_state(); 602 603 if (save_state == _thread_blocked && is_suspend_equivalent()) { 604 // If the thread's state is _thread_blocked and this blocking 605 // condition is known to be equivalent to a suspend, then we can 606 // consider the thread to be externally suspended. This means that 607 // the code that sets _thread_blocked has been modified to do 608 // self-suspension if the blocking condition releases. We also 609 // used to check for CONDVAR_WAIT here, but that is now covered by 610 // the _thread_blocked with self-suspension check. 611 // 612 // Return true since we wouldn't be here unless there was still an 613 // external suspend request. 614 *bits |= 0x00001000; 615 return true; 616 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 617 // Threads running native code will self-suspend on native==>VM/Java 618 // transitions. If its stack is walkable (should always be the case 619 // unless this function is called before the actual java_suspend() 620 // call), then the wait is done. 621 *bits |= 0x00002000; 622 return true; 623 } else if (!called_by_wait && !did_trans_retry && 624 save_state == _thread_in_native_trans && 625 frame_anchor()->walkable()) { 626 // The thread is transitioning from thread_in_native to another 627 // thread state. check_safepoint_and_suspend_for_native_trans() 628 // will force the thread to self-suspend. If it hasn't gotten 629 // there yet we may have caught the thread in-between the native 630 // code check above and the self-suspend. Lucky us. If we were 631 // called by wait_for_ext_suspend_completion(), then it 632 // will be doing the retries so we don't have to. 633 // 634 // Since we use the saved thread state in the if-statement above, 635 // there is a chance that the thread has already transitioned to 636 // _thread_blocked by the time we get here. In that case, we will 637 // make a single unnecessary pass through the logic below. This 638 // doesn't hurt anything since we still do the trans retry. 639 640 *bits |= 0x00004000; 641 642 // Once the thread leaves thread_in_native_trans for another 643 // thread state, we break out of this retry loop. We shouldn't 644 // need this flag to prevent us from getting back here, but 645 // sometimes paranoia is good. 646 did_trans_retry = true; 647 648 // We wait for the thread to transition to a more usable state. 649 for (int i = 1; i <= SuspendRetryCount; i++) { 650 // We used to do an "os::yield_all(i)" call here with the intention 651 // that yielding would increase on each retry. However, the parameter 652 // is ignored on Linux which means the yield didn't scale up. Waiting 653 // on the SR_lock below provides a much more predictable scale up for 654 // the delay. It also provides a simple/direct point to check for any 655 // safepoint requests from the VMThread 656 657 // temporarily drops SR_lock while doing wait with safepoint check 658 // (if we're a JavaThread - the WatcherThread can also call this) 659 // and increase delay with each retry 660 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 661 662 // check the actual thread state instead of what we saved above 663 if (thread_state() != _thread_in_native_trans) { 664 // the thread has transitioned to another thread state so 665 // try all the checks (except this one) one more time. 666 do_trans_retry = true; 667 break; 668 } 669 } // end retry loop 670 671 672 } 673 } while (do_trans_retry); 674 675 *bits |= 0x00000010; 676 return false; 677} 678 679// 680// Wait for an external suspend request to complete (or be cancelled). 681// Returns true if the thread is externally suspended and false otherwise. 682// 683bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 684 uint32_t *bits) { 685 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 686 false /* !called_by_wait */, bits); 687 688 // local flag copies to minimize SR_lock hold time 689 bool is_suspended; 690 bool pending; 691 uint32_t reset_bits; 692 693 // set a marker so is_ext_suspend_completed() knows we are the caller 694 *bits |= 0x00010000; 695 696 // We use reset_bits to reinitialize the bits value at the top of 697 // each retry loop. This allows the caller to make use of any 698 // unused bits for their own marking purposes. 699 reset_bits = *bits; 700 701 { 702 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 703 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 704 delay, bits); 705 pending = is_external_suspend(); 706 } 707 // must release SR_lock to allow suspension to complete 708 709 if (!pending) { 710 // A cancelled suspend request is the only false return from 711 // is_ext_suspend_completed() that keeps us from entering the 712 // retry loop. 713 *bits |= 0x00020000; 714 return false; 715 } 716 717 if (is_suspended) { 718 *bits |= 0x00040000; 719 return true; 720 } 721 722 for (int i = 1; i <= retries; i++) { 723 *bits = reset_bits; // reinit to only track last retry 724 725 // We used to do an "os::yield_all(i)" call here with the intention 726 // that yielding would increase on each retry. However, the parameter 727 // is ignored on Linux which means the yield didn't scale up. Waiting 728 // on the SR_lock below provides a much more predictable scale up for 729 // the delay. It also provides a simple/direct point to check for any 730 // safepoint requests from the VMThread 731 732 { 733 MutexLocker ml(SR_lock()); 734 // wait with safepoint check (if we're a JavaThread - the WatcherThread 735 // can also call this) and increase delay with each retry 736 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 737 738 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 739 delay, bits); 740 741 // It is possible for the external suspend request to be cancelled 742 // (by a resume) before the actual suspend operation is completed. 743 // Refresh our local copy to see if we still need to wait. 744 pending = is_external_suspend(); 745 } 746 747 if (!pending) { 748 // A cancelled suspend request is the only false return from 749 // is_ext_suspend_completed() that keeps us from staying in the 750 // retry loop. 751 *bits |= 0x00080000; 752 return false; 753 } 754 755 if (is_suspended) { 756 *bits |= 0x00100000; 757 return true; 758 } 759 } // end retry loop 760 761 // thread did not suspend after all our retries 762 *bits |= 0x00200000; 763 return false; 764} 765 766#ifndef PRODUCT 767void JavaThread::record_jump(address target, address instr, const char* file, int line) { 768 769 // This should not need to be atomic as the only way for simultaneous 770 // updates is via interrupts. Even then this should be rare or non-existant 771 // and we don't care that much anyway. 772 773 int index = _jmp_ring_index; 774 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 775 _jmp_ring[index]._target = (intptr_t) target; 776 _jmp_ring[index]._instruction = (intptr_t) instr; 777 _jmp_ring[index]._file = file; 778 _jmp_ring[index]._line = line; 779} 780#endif /* PRODUCT */ 781 782// Called by flat profiler 783// Callers have already called wait_for_ext_suspend_completion 784// The assertion for that is currently too complex to put here: 785bool JavaThread::profile_last_Java_frame(frame* _fr) { 786 bool gotframe = false; 787 // self suspension saves needed state. 788 if (has_last_Java_frame() && _anchor.walkable()) { 789 *_fr = pd_last_frame(); 790 gotframe = true; 791 } 792 return gotframe; 793} 794 795void Thread::interrupt(Thread* thread) { 796 trace("interrupt", thread); 797 debug_only(check_for_dangling_thread_pointer(thread);) 798 os::interrupt(thread); 799} 800 801bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 802 trace("is_interrupted", thread); 803 debug_only(check_for_dangling_thread_pointer(thread);) 804 // Note: If clear_interrupted==false, this simply fetches and 805 // returns the value of the field osthread()->interrupted(). 806 return os::is_interrupted(thread, clear_interrupted); 807} 808 809 810// GC Support 811bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 812 jint thread_parity = _oops_do_parity; 813 if (thread_parity != strong_roots_parity) { 814 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 815 if (res == thread_parity) { 816 return true; 817 } else { 818 guarantee(res == strong_roots_parity, "Or else what?"); 819 assert(SharedHeap::heap()->workers()->active_workers() > 0, 820 "Should only fail when parallel."); 821 return false; 822 } 823 } 824 assert(SharedHeap::heap()->workers()->active_workers() > 0, 825 "Should only fail when parallel."); 826 return false; 827} 828 829void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 830 active_handles()->oops_do(f); 831 // Do oop for ThreadShadow 832 f->do_oop((oop*)&_pending_exception); 833 handle_area()->oops_do(f); 834} 835 836void Thread::nmethods_do(CodeBlobClosure* cf) { 837 // no nmethods in a generic thread... 838} 839 840void Thread::metadata_do(void f(Metadata*)) { 841 if (metadata_handles() != NULL) { 842 for (int i = 0; i< metadata_handles()->length(); i++) { 843 f(metadata_handles()->at(i)); 844 } 845 } 846} 847 848void Thread::print_on(outputStream* st) const { 849 // get_priority assumes osthread initialized 850 if (osthread() != NULL) { 851 int os_prio; 852 if (os::get_native_priority(this, &os_prio) == OS_OK) { 853 st->print("os_prio=%d ", os_prio); 854 } 855 st->print("tid=" INTPTR_FORMAT " ", this); 856 osthread()->print_on(st); 857 } 858 debug_only(if (WizardMode) print_owned_locks_on(st);) 859} 860 861// Thread::print_on_error() is called by fatal error handler. Don't use 862// any lock or allocate memory. 863void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 864 if (is_VM_thread()) st->print("VMThread"); 865 else if (is_Compiler_thread()) st->print("CompilerThread"); 866 else if (is_Java_thread()) st->print("JavaThread"); 867 else if (is_GC_task_thread()) st->print("GCTaskThread"); 868 else if (is_Watcher_thread()) st->print("WatcherThread"); 869 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 870 else st->print("Thread"); 871 872 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 873 _stack_base - _stack_size, _stack_base); 874 875 if (osthread()) { 876 st->print(" [id=%d]", osthread()->thread_id()); 877 } 878} 879 880#ifdef ASSERT 881void Thread::print_owned_locks_on(outputStream* st) const { 882 Monitor *cur = _owned_locks; 883 if (cur == NULL) { 884 st->print(" (no locks) "); 885 } else { 886 st->print_cr(" Locks owned:"); 887 while(cur) { 888 cur->print_on(st); 889 cur = cur->next(); 890 } 891 } 892} 893 894static int ref_use_count = 0; 895 896bool Thread::owns_locks_but_compiled_lock() const { 897 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 898 if (cur != Compile_lock) return true; 899 } 900 return false; 901} 902 903 904#endif 905 906#ifndef PRODUCT 907 908// The flag: potential_vm_operation notifies if this particular safepoint state could potential 909// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 910// no threads which allow_vm_block's are held 911void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 912 // Check if current thread is allowed to block at a safepoint 913 if (!(_allow_safepoint_count == 0)) 914 fatal("Possible safepoint reached by thread that does not allow it"); 915 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 916 fatal("LEAF method calling lock?"); 917 } 918 919#ifdef ASSERT 920 if (potential_vm_operation && is_Java_thread() 921 && !Universe::is_bootstrapping()) { 922 // Make sure we do not hold any locks that the VM thread also uses. 923 // This could potentially lead to deadlocks 924 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 925 // Threads_lock is special, since the safepoint synchronization will not start before this is 926 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 927 // since it is used to transfer control between JavaThreads and the VMThread 928 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first! 929 if ( (cur->allow_vm_block() && 930 cur != Threads_lock && 931 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation 932 cur != VMOperationRequest_lock && 933 cur != VMOperationQueue_lock) || 934 cur->rank() == Mutex::special) { 935 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 936 } 937 } 938 } 939 940 if (GCALotAtAllSafepoints) { 941 // We could enter a safepoint here and thus have a gc 942 InterfaceSupport::check_gc_alot(); 943 } 944#endif 945} 946#endif 947 948bool Thread::is_in_stack(address adr) const { 949 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 950 address end = os::current_stack_pointer(); 951 // Allow non Java threads to call this without stack_base 952 if (_stack_base == NULL) return true; 953 if (stack_base() >= adr && adr >= end) return true; 954 955 return false; 956} 957 958 959// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 960// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 961// used for compilation in the future. If that change is made, the need for these methods 962// should be revisited, and they should be removed if possible. 963 964bool Thread::is_lock_owned(address adr) const { 965 return on_local_stack(adr); 966} 967 968bool Thread::set_as_starting_thread() { 969 // NOTE: this must be called inside the main thread. 970 return os::create_main_thread((JavaThread*)this); 971} 972 973static void initialize_class(Symbol* class_name, TRAPS) { 974 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 975 InstanceKlass::cast(klass)->initialize(CHECK); 976} 977 978 979// Creates the initial ThreadGroup 980static Handle create_initial_thread_group(TRAPS) { 981 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 982 instanceKlassHandle klass (THREAD, k); 983 984 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 985 { 986 JavaValue result(T_VOID); 987 JavaCalls::call_special(&result, 988 system_instance, 989 klass, 990 vmSymbols::object_initializer_name(), 991 vmSymbols::void_method_signature(), 992 CHECK_NH); 993 } 994 Universe::set_system_thread_group(system_instance()); 995 996 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 997 { 998 JavaValue result(T_VOID); 999 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 1000 JavaCalls::call_special(&result, 1001 main_instance, 1002 klass, 1003 vmSymbols::object_initializer_name(), 1004 vmSymbols::threadgroup_string_void_signature(), 1005 system_instance, 1006 string, 1007 CHECK_NH); 1008 } 1009 return main_instance; 1010} 1011 1012// Creates the initial Thread 1013static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1014 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1015 instanceKlassHandle klass (THREAD, k); 1016 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1017 1018 java_lang_Thread::set_thread(thread_oop(), thread); 1019 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1020 thread->set_threadObj(thread_oop()); 1021 1022 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1023 1024 JavaValue result(T_VOID); 1025 JavaCalls::call_special(&result, thread_oop, 1026 klass, 1027 vmSymbols::object_initializer_name(), 1028 vmSymbols::threadgroup_string_void_signature(), 1029 thread_group, 1030 string, 1031 CHECK_NULL); 1032 return thread_oop(); 1033} 1034 1035static void call_initializeSystemClass(TRAPS) { 1036 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1037 instanceKlassHandle klass (THREAD, k); 1038 1039 JavaValue result(T_VOID); 1040 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1041 vmSymbols::void_method_signature(), CHECK); 1042} 1043 1044char java_runtime_name[128] = ""; 1045char java_runtime_version[128] = ""; 1046 1047// extract the JRE name from sun.misc.Version.java_runtime_name 1048static const char* get_java_runtime_name(TRAPS) { 1049 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1050 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1051 fieldDescriptor fd; 1052 bool found = k != NULL && 1053 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1054 vmSymbols::string_signature(), &fd); 1055 if (found) { 1056 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1057 if (name_oop == NULL) 1058 return NULL; 1059 const char* name = java_lang_String::as_utf8_string(name_oop, 1060 java_runtime_name, 1061 sizeof(java_runtime_name)); 1062 return name; 1063 } else { 1064 return NULL; 1065 } 1066} 1067 1068// extract the JRE version from sun.misc.Version.java_runtime_version 1069static const char* get_java_runtime_version(TRAPS) { 1070 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1071 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1072 fieldDescriptor fd; 1073 bool found = k != NULL && 1074 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1075 vmSymbols::string_signature(), &fd); 1076 if (found) { 1077 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1078 if (name_oop == NULL) 1079 return NULL; 1080 const char* name = java_lang_String::as_utf8_string(name_oop, 1081 java_runtime_version, 1082 sizeof(java_runtime_version)); 1083 return name; 1084 } else { 1085 return NULL; 1086 } 1087} 1088 1089// General purpose hook into Java code, run once when the VM is initialized. 1090// The Java library method itself may be changed independently from the VM. 1091static void call_postVMInitHook(TRAPS) { 1092 Klass* k = SystemDictionary::PostVMInitHook_klass(); 1093 instanceKlassHandle klass (THREAD, k); 1094 if (klass.not_null()) { 1095 JavaValue result(T_VOID); 1096 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1097 vmSymbols::void_method_signature(), 1098 CHECK); 1099 } 1100} 1101 1102static void reset_vm_info_property(TRAPS) { 1103 // the vm info string 1104 ResourceMark rm(THREAD); 1105 const char *vm_info = VM_Version::vm_info_string(); 1106 1107 // java.lang.System class 1108 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1109 instanceKlassHandle klass (THREAD, k); 1110 1111 // setProperty arguments 1112 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1113 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1114 1115 // return value 1116 JavaValue r(T_OBJECT); 1117 1118 // public static String setProperty(String key, String value); 1119 JavaCalls::call_static(&r, 1120 klass, 1121 vmSymbols::setProperty_name(), 1122 vmSymbols::string_string_string_signature(), 1123 key_str, 1124 value_str, 1125 CHECK); 1126} 1127 1128 1129void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1130 assert(thread_group.not_null(), "thread group should be specified"); 1131 assert(threadObj() == NULL, "should only create Java thread object once"); 1132 1133 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1134 instanceKlassHandle klass (THREAD, k); 1135 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1136 1137 java_lang_Thread::set_thread(thread_oop(), this); 1138 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1139 set_threadObj(thread_oop()); 1140 1141 JavaValue result(T_VOID); 1142 if (thread_name != NULL) { 1143 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1144 // Thread gets assigned specified name and null target 1145 JavaCalls::call_special(&result, 1146 thread_oop, 1147 klass, 1148 vmSymbols::object_initializer_name(), 1149 vmSymbols::threadgroup_string_void_signature(), 1150 thread_group, // Argument 1 1151 name, // Argument 2 1152 THREAD); 1153 } else { 1154 // Thread gets assigned name "Thread-nnn" and null target 1155 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1156 JavaCalls::call_special(&result, 1157 thread_oop, 1158 klass, 1159 vmSymbols::object_initializer_name(), 1160 vmSymbols::threadgroup_runnable_void_signature(), 1161 thread_group, // Argument 1 1162 Handle(), // Argument 2 1163 THREAD); 1164 } 1165 1166 1167 if (daemon) { 1168 java_lang_Thread::set_daemon(thread_oop()); 1169 } 1170 1171 if (HAS_PENDING_EXCEPTION) { 1172 return; 1173 } 1174 1175 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1176 Handle threadObj(this, this->threadObj()); 1177 1178 JavaCalls::call_special(&result, 1179 thread_group, 1180 group, 1181 vmSymbols::add_method_name(), 1182 vmSymbols::thread_void_signature(), 1183 threadObj, // Arg 1 1184 THREAD); 1185 1186 1187} 1188 1189// NamedThread -- non-JavaThread subclasses with multiple 1190// uniquely named instances should derive from this. 1191NamedThread::NamedThread() : Thread() { 1192 _name = NULL; 1193 _processed_thread = NULL; 1194} 1195 1196NamedThread::~NamedThread() { 1197 if (_name != NULL) { 1198 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1199 _name = NULL; 1200 } 1201} 1202 1203void NamedThread::set_name(const char* format, ...) { 1204 guarantee(_name == NULL, "Only get to set name once."); 1205 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1206 guarantee(_name != NULL, "alloc failure"); 1207 va_list ap; 1208 va_start(ap, format); 1209 jio_vsnprintf(_name, max_name_len, format, ap); 1210 va_end(ap); 1211} 1212 1213// ======= WatcherThread ======== 1214 1215// The watcher thread exists to simulate timer interrupts. It should 1216// be replaced by an abstraction over whatever native support for 1217// timer interrupts exists on the platform. 1218 1219WatcherThread* WatcherThread::_watcher_thread = NULL; 1220bool WatcherThread::_startable = false; 1221volatile bool WatcherThread::_should_terminate = false; 1222 1223WatcherThread::WatcherThread() : Thread() { 1224 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1225 if (os::create_thread(this, os::watcher_thread)) { 1226 _watcher_thread = this; 1227 1228 // Set the watcher thread to the highest OS priority which should not be 1229 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1230 // is created. The only normal thread using this priority is the reference 1231 // handler thread, which runs for very short intervals only. 1232 // If the VMThread's priority is not lower than the WatcherThread profiling 1233 // will be inaccurate. 1234 os::set_priority(this, MaxPriority); 1235 if (!DisableStartThread) { 1236 os::start_thread(this); 1237 } 1238 } 1239} 1240 1241int WatcherThread::sleep() const { 1242 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1243 1244 // remaining will be zero if there are no tasks, 1245 // causing the WatcherThread to sleep until a task is 1246 // enrolled 1247 int remaining = PeriodicTask::time_to_wait(); 1248 int time_slept = 0; 1249 1250 // we expect this to timeout - we only ever get unparked when 1251 // we should terminate or when a new task has been enrolled 1252 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1253 1254 jlong time_before_loop = os::javaTimeNanos(); 1255 1256 for (;;) { 1257 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1258 jlong now = os::javaTimeNanos(); 1259 1260 if (remaining == 0) { 1261 // if we didn't have any tasks we could have waited for a long time 1262 // consider the time_slept zero and reset time_before_loop 1263 time_slept = 0; 1264 time_before_loop = now; 1265 } else { 1266 // need to recalulate since we might have new tasks in _tasks 1267 time_slept = (int) ((now - time_before_loop) / 1000000); 1268 } 1269 1270 // Change to task list or spurious wakeup of some kind 1271 if (timedout || _should_terminate) { 1272 break; 1273 } 1274 1275 remaining = PeriodicTask::time_to_wait(); 1276 if (remaining == 0) { 1277 // Last task was just disenrolled so loop around and wait until 1278 // another task gets enrolled 1279 continue; 1280 } 1281 1282 remaining -= time_slept; 1283 if (remaining <= 0) 1284 break; 1285 } 1286 1287 return time_slept; 1288} 1289 1290void WatcherThread::run() { 1291 assert(this == watcher_thread(), "just checking"); 1292 1293 this->record_stack_base_and_size(); 1294 this->initialize_thread_local_storage(); 1295 this->set_active_handles(JNIHandleBlock::allocate_block()); 1296 while(!_should_terminate) { 1297 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1298 assert(watcher_thread() == this, "thread consistency check"); 1299 1300 // Calculate how long it'll be until the next PeriodicTask work 1301 // should be done, and sleep that amount of time. 1302 int time_waited = sleep(); 1303 1304 if (is_error_reported()) { 1305 // A fatal error has happened, the error handler(VMError::report_and_die) 1306 // should abort JVM after creating an error log file. However in some 1307 // rare cases, the error handler itself might deadlock. Here we try to 1308 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1309 // 1310 // This code is in WatcherThread because WatcherThread wakes up 1311 // periodically so the fatal error handler doesn't need to do anything; 1312 // also because the WatcherThread is less likely to crash than other 1313 // threads. 1314 1315 for (;;) { 1316 if (!ShowMessageBoxOnError 1317 && (OnError == NULL || OnError[0] == '\0') 1318 && Arguments::abort_hook() == NULL) { 1319 os::sleep(this, 2 * 60 * 1000, false); 1320 fdStream err(defaultStream::output_fd()); 1321 err.print_raw_cr("# [ timer expired, abort... ]"); 1322 // skip atexit/vm_exit/vm_abort hooks 1323 os::die(); 1324 } 1325 1326 // Wake up 5 seconds later, the fatal handler may reset OnError or 1327 // ShowMessageBoxOnError when it is ready to abort. 1328 os::sleep(this, 5 * 1000, false); 1329 } 1330 } 1331 1332 PeriodicTask::real_time_tick(time_waited); 1333 } 1334 1335 // Signal that it is terminated 1336 { 1337 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1338 _watcher_thread = NULL; 1339 Terminator_lock->notify(); 1340 } 1341 1342 // Thread destructor usually does this.. 1343 ThreadLocalStorage::set_thread(NULL); 1344} 1345 1346void WatcherThread::start() { 1347 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1348 1349 if (watcher_thread() == NULL && _startable) { 1350 _should_terminate = false; 1351 // Create the single instance of WatcherThread 1352 new WatcherThread(); 1353 } 1354} 1355 1356void WatcherThread::make_startable() { 1357 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1358 _startable = true; 1359} 1360 1361void WatcherThread::stop() { 1362 { 1363 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1364 _should_terminate = true; 1365 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1366 1367 WatcherThread* watcher = watcher_thread(); 1368 if (watcher != NULL) 1369 watcher->unpark(); 1370 } 1371 1372 // it is ok to take late safepoints here, if needed 1373 MutexLocker mu(Terminator_lock); 1374 1375 while(watcher_thread() != NULL) { 1376 // This wait should make safepoint checks, wait without a timeout, 1377 // and wait as a suspend-equivalent condition. 1378 // 1379 // Note: If the FlatProfiler is running, then this thread is waiting 1380 // for the WatcherThread to terminate and the WatcherThread, via the 1381 // FlatProfiler task, is waiting for the external suspend request on 1382 // this thread to complete. wait_for_ext_suspend_completion() will 1383 // eventually timeout, but that takes time. Making this wait a 1384 // suspend-equivalent condition solves that timeout problem. 1385 // 1386 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1387 Mutex::_as_suspend_equivalent_flag); 1388 } 1389} 1390 1391void WatcherThread::unpark() { 1392 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1393 PeriodicTask_lock->notify(); 1394} 1395 1396void WatcherThread::print_on(outputStream* st) const { 1397 st->print("\"%s\" ", name()); 1398 Thread::print_on(st); 1399 st->cr(); 1400} 1401 1402// ======= JavaThread ======== 1403 1404// A JavaThread is a normal Java thread 1405 1406void JavaThread::initialize() { 1407 // Initialize fields 1408 1409 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1410 set_claimed_par_id(-1); 1411 1412 set_saved_exception_pc(NULL); 1413 set_threadObj(NULL); 1414 _anchor.clear(); 1415 set_entry_point(NULL); 1416 set_jni_functions(jni_functions()); 1417 set_callee_target(NULL); 1418 set_vm_result(NULL); 1419 set_vm_result_2(NULL); 1420 set_vframe_array_head(NULL); 1421 set_vframe_array_last(NULL); 1422 set_deferred_locals(NULL); 1423 set_deopt_mark(NULL); 1424 set_deopt_nmethod(NULL); 1425 clear_must_deopt_id(); 1426 set_monitor_chunks(NULL); 1427 set_next(NULL); 1428 set_thread_state(_thread_new); 1429#if INCLUDE_NMT 1430 set_recorder(NULL); 1431#endif 1432 _terminated = _not_terminated; 1433 _privileged_stack_top = NULL; 1434 _array_for_gc = NULL; 1435 _suspend_equivalent = false; 1436 _in_deopt_handler = 0; 1437 _doing_unsafe_access = false; 1438 _stack_guard_state = stack_guard_unused; 1439 _exception_oop = NULL; 1440 _exception_pc = 0; 1441 _exception_handler_pc = 0; 1442 _is_method_handle_return = 0; 1443 _jvmti_thread_state= NULL; 1444 _should_post_on_exceptions_flag = JNI_FALSE; 1445 _jvmti_get_loaded_classes_closure = NULL; 1446 _interp_only_mode = 0; 1447 _special_runtime_exit_condition = _no_async_condition; 1448 _pending_async_exception = NULL; 1449 _is_compiling = false; 1450 _thread_stat = NULL; 1451 _thread_stat = new ThreadStatistics(); 1452 _blocked_on_compilation = false; 1453 _jni_active_critical = 0; 1454 _do_not_unlock_if_synchronized = false; 1455 _cached_monitor_info = NULL; 1456 _parker = Parker::Allocate(this) ; 1457 1458#ifndef PRODUCT 1459 _jmp_ring_index = 0; 1460 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1461 record_jump(NULL, NULL, NULL, 0); 1462 } 1463#endif /* PRODUCT */ 1464 1465 set_thread_profiler(NULL); 1466 if (FlatProfiler::is_active()) { 1467 // This is where we would decide to either give each thread it's own profiler 1468 // or use one global one from FlatProfiler, 1469 // or up to some count of the number of profiled threads, etc. 1470 ThreadProfiler* pp = new ThreadProfiler(); 1471 pp->engage(); 1472 set_thread_profiler(pp); 1473 } 1474 1475 // Setup safepoint state info for this thread 1476 ThreadSafepointState::create(this); 1477 1478 debug_only(_java_call_counter = 0); 1479 1480 // JVMTI PopFrame support 1481 _popframe_condition = popframe_inactive; 1482 _popframe_preserved_args = NULL; 1483 _popframe_preserved_args_size = 0; 1484 1485 pd_initialize(); 1486} 1487 1488#if INCLUDE_ALL_GCS 1489SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1490DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1491#endif // INCLUDE_ALL_GCS 1492 1493JavaThread::JavaThread(bool is_attaching_via_jni) : 1494 Thread() 1495#if INCLUDE_ALL_GCS 1496 , _satb_mark_queue(&_satb_mark_queue_set), 1497 _dirty_card_queue(&_dirty_card_queue_set) 1498#endif // INCLUDE_ALL_GCS 1499{ 1500 initialize(); 1501 if (is_attaching_via_jni) { 1502 _jni_attach_state = _attaching_via_jni; 1503 } else { 1504 _jni_attach_state = _not_attaching_via_jni; 1505 } 1506 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1507 _safepoint_visible = false; 1508} 1509 1510bool JavaThread::reguard_stack(address cur_sp) { 1511 if (_stack_guard_state != stack_guard_yellow_disabled) { 1512 return true; // Stack already guarded or guard pages not needed. 1513 } 1514 1515 if (register_stack_overflow()) { 1516 // For those architectures which have separate register and 1517 // memory stacks, we must check the register stack to see if 1518 // it has overflowed. 1519 return false; 1520 } 1521 1522 // Java code never executes within the yellow zone: the latter is only 1523 // there to provoke an exception during stack banging. If java code 1524 // is executing there, either StackShadowPages should be larger, or 1525 // some exception code in c1, c2 or the interpreter isn't unwinding 1526 // when it should. 1527 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1528 1529 enable_stack_yellow_zone(); 1530 return true; 1531} 1532 1533bool JavaThread::reguard_stack(void) { 1534 return reguard_stack(os::current_stack_pointer()); 1535} 1536 1537 1538void JavaThread::block_if_vm_exited() { 1539 if (_terminated == _vm_exited) { 1540 // _vm_exited is set at safepoint, and Threads_lock is never released 1541 // we will block here forever 1542 Threads_lock->lock_without_safepoint_check(); 1543 ShouldNotReachHere(); 1544 } 1545} 1546 1547 1548// Remove this ifdef when C1 is ported to the compiler interface. 1549static void compiler_thread_entry(JavaThread* thread, TRAPS); 1550 1551JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1552 Thread() 1553#if INCLUDE_ALL_GCS 1554 , _satb_mark_queue(&_satb_mark_queue_set), 1555 _dirty_card_queue(&_dirty_card_queue_set) 1556#endif // INCLUDE_ALL_GCS 1557{ 1558 if (TraceThreadEvents) { 1559 tty->print_cr("creating thread %p", this); 1560 } 1561 initialize(); 1562 _jni_attach_state = _not_attaching_via_jni; 1563 set_entry_point(entry_point); 1564 // Create the native thread itself. 1565 // %note runtime_23 1566 os::ThreadType thr_type = os::java_thread; 1567 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1568 os::java_thread; 1569 os::create_thread(this, thr_type, stack_sz); 1570 _safepoint_visible = false; 1571 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1572 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1573 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1574 // the exception consists of creating the exception object & initializing it, initialization 1575 // will leave the VM via a JavaCall and then all locks must be unlocked). 1576 // 1577 // The thread is still suspended when we reach here. Thread must be explicit started 1578 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1579 // by calling Threads:add. The reason why this is not done here, is because the thread 1580 // object must be fully initialized (take a look at JVM_Start) 1581} 1582 1583JavaThread::~JavaThread() { 1584 if (TraceThreadEvents) { 1585 tty->print_cr("terminate thread %p", this); 1586 } 1587 1588 // By now, this thread should already be invisible to safepoint, 1589 // and its per-thread recorder also collected. 1590 assert(!is_safepoint_visible(), "wrong state"); 1591#if INCLUDE_NMT 1592 assert(get_recorder() == NULL, "Already collected"); 1593#endif // INCLUDE_NMT 1594 1595 // JSR166 -- return the parker to the free list 1596 Parker::Release(_parker); 1597 _parker = NULL ; 1598 1599 // Free any remaining previous UnrollBlock 1600 vframeArray* old_array = vframe_array_last(); 1601 1602 if (old_array != NULL) { 1603 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1604 old_array->set_unroll_block(NULL); 1605 delete old_info; 1606 delete old_array; 1607 } 1608 1609 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1610 if (deferred != NULL) { 1611 // This can only happen if thread is destroyed before deoptimization occurs. 1612 assert(deferred->length() != 0, "empty array!"); 1613 do { 1614 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1615 deferred->remove_at(0); 1616 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1617 delete dlv; 1618 } while (deferred->length() != 0); 1619 delete deferred; 1620 } 1621 1622 // All Java related clean up happens in exit 1623 ThreadSafepointState::destroy(this); 1624 if (_thread_profiler != NULL) delete _thread_profiler; 1625 if (_thread_stat != NULL) delete _thread_stat; 1626} 1627 1628 1629// The first routine called by a new Java thread 1630void JavaThread::run() { 1631 // initialize thread-local alloc buffer related fields 1632 this->initialize_tlab(); 1633 1634 // used to test validitity of stack trace backs 1635 this->record_base_of_stack_pointer(); 1636 1637 // Record real stack base and size. 1638 this->record_stack_base_and_size(); 1639 1640 // Initialize thread local storage; set before calling MutexLocker 1641 this->initialize_thread_local_storage(); 1642 1643 this->create_stack_guard_pages(); 1644 1645 this->cache_global_variables(); 1646 1647 // Thread is now sufficient initialized to be handled by the safepoint code as being 1648 // in the VM. Change thread state from _thread_new to _thread_in_vm 1649 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1650 1651 assert(JavaThread::current() == this, "sanity check"); 1652 assert(!Thread::current()->owns_locks(), "sanity check"); 1653 1654 DTRACE_THREAD_PROBE(start, this); 1655 1656 // This operation might block. We call that after all safepoint checks for a new thread has 1657 // been completed. 1658 this->set_active_handles(JNIHandleBlock::allocate_block()); 1659 1660 if (JvmtiExport::should_post_thread_life()) { 1661 JvmtiExport::post_thread_start(this); 1662 } 1663 1664 EventThreadStart event; 1665 if (event.should_commit()) { 1666 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1667 event.commit(); 1668 } 1669 1670 // We call another function to do the rest so we are sure that the stack addresses used 1671 // from there will be lower than the stack base just computed 1672 thread_main_inner(); 1673 1674 // Note, thread is no longer valid at this point! 1675} 1676 1677 1678void JavaThread::thread_main_inner() { 1679 assert(JavaThread::current() == this, "sanity check"); 1680 assert(this->threadObj() != NULL, "just checking"); 1681 1682 // Execute thread entry point unless this thread has a pending exception 1683 // or has been stopped before starting. 1684 // Note: Due to JVM_StopThread we can have pending exceptions already! 1685 if (!this->has_pending_exception() && 1686 !java_lang_Thread::is_stillborn(this->threadObj())) { 1687 { 1688 ResourceMark rm(this); 1689 this->set_native_thread_name(this->get_thread_name()); 1690 } 1691 HandleMark hm(this); 1692 this->entry_point()(this, this); 1693 } 1694 1695 DTRACE_THREAD_PROBE(stop, this); 1696 1697 this->exit(false); 1698 delete this; 1699} 1700 1701 1702static void ensure_join(JavaThread* thread) { 1703 // We do not need to grap the Threads_lock, since we are operating on ourself. 1704 Handle threadObj(thread, thread->threadObj()); 1705 assert(threadObj.not_null(), "java thread object must exist"); 1706 ObjectLocker lock(threadObj, thread); 1707 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1708 thread->clear_pending_exception(); 1709 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1710 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1711 // Clear the native thread instance - this makes isAlive return false and allows the join() 1712 // to complete once we've done the notify_all below 1713 java_lang_Thread::set_thread(threadObj(), NULL); 1714 lock.notify_all(thread); 1715 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1716 thread->clear_pending_exception(); 1717} 1718 1719 1720// For any new cleanup additions, please check to see if they need to be applied to 1721// cleanup_failed_attach_current_thread as well. 1722void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1723 assert(this == JavaThread::current(), "thread consistency check"); 1724 1725 HandleMark hm(this); 1726 Handle uncaught_exception(this, this->pending_exception()); 1727 this->clear_pending_exception(); 1728 Handle threadObj(this, this->threadObj()); 1729 assert(threadObj.not_null(), "Java thread object should be created"); 1730 1731 if (get_thread_profiler() != NULL) { 1732 get_thread_profiler()->disengage(); 1733 ResourceMark rm; 1734 get_thread_profiler()->print(get_thread_name()); 1735 } 1736 1737 1738 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1739 { 1740 EXCEPTION_MARK; 1741 1742 CLEAR_PENDING_EXCEPTION; 1743 } 1744 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1745 // has to be fixed by a runtime query method 1746 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1747 // JSR-166: change call from from ThreadGroup.uncaughtException to 1748 // java.lang.Thread.dispatchUncaughtException 1749 if (uncaught_exception.not_null()) { 1750 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1751 { 1752 EXCEPTION_MARK; 1753 // Check if the method Thread.dispatchUncaughtException() exists. If so 1754 // call it. Otherwise we have an older library without the JSR-166 changes, 1755 // so call ThreadGroup.uncaughtException() 1756 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1757 CallInfo callinfo; 1758 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1759 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1760 vmSymbols::dispatchUncaughtException_name(), 1761 vmSymbols::throwable_void_signature(), 1762 KlassHandle(), false, false, THREAD); 1763 CLEAR_PENDING_EXCEPTION; 1764 methodHandle method = callinfo.selected_method(); 1765 if (method.not_null()) { 1766 JavaValue result(T_VOID); 1767 JavaCalls::call_virtual(&result, 1768 threadObj, thread_klass, 1769 vmSymbols::dispatchUncaughtException_name(), 1770 vmSymbols::throwable_void_signature(), 1771 uncaught_exception, 1772 THREAD); 1773 } else { 1774 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1775 JavaValue result(T_VOID); 1776 JavaCalls::call_virtual(&result, 1777 group, thread_group, 1778 vmSymbols::uncaughtException_name(), 1779 vmSymbols::thread_throwable_void_signature(), 1780 threadObj, // Arg 1 1781 uncaught_exception, // Arg 2 1782 THREAD); 1783 } 1784 if (HAS_PENDING_EXCEPTION) { 1785 ResourceMark rm(this); 1786 jio_fprintf(defaultStream::error_stream(), 1787 "\nException: %s thrown from the UncaughtExceptionHandler" 1788 " in thread \"%s\"\n", 1789 pending_exception()->klass()->external_name(), 1790 get_thread_name()); 1791 CLEAR_PENDING_EXCEPTION; 1792 } 1793 } 1794 } 1795 1796 // Called before the java thread exit since we want to read info 1797 // from java_lang_Thread object 1798 EventThreadEnd event; 1799 if (event.should_commit()) { 1800 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1801 event.commit(); 1802 } 1803 1804 // Call after last event on thread 1805 EVENT_THREAD_EXIT(this); 1806 1807 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1808 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1809 // is deprecated anyhow. 1810 { int count = 3; 1811 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1812 EXCEPTION_MARK; 1813 JavaValue result(T_VOID); 1814 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1815 JavaCalls::call_virtual(&result, 1816 threadObj, thread_klass, 1817 vmSymbols::exit_method_name(), 1818 vmSymbols::void_method_signature(), 1819 THREAD); 1820 CLEAR_PENDING_EXCEPTION; 1821 } 1822 } 1823 1824 // notify JVMTI 1825 if (JvmtiExport::should_post_thread_life()) { 1826 JvmtiExport::post_thread_end(this); 1827 } 1828 1829 // We have notified the agents that we are exiting, before we go on, 1830 // we must check for a pending external suspend request and honor it 1831 // in order to not surprise the thread that made the suspend request. 1832 while (true) { 1833 { 1834 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1835 if (!is_external_suspend()) { 1836 set_terminated(_thread_exiting); 1837 ThreadService::current_thread_exiting(this); 1838 break; 1839 } 1840 // Implied else: 1841 // Things get a little tricky here. We have a pending external 1842 // suspend request, but we are holding the SR_lock so we 1843 // can't just self-suspend. So we temporarily drop the lock 1844 // and then self-suspend. 1845 } 1846 1847 ThreadBlockInVM tbivm(this); 1848 java_suspend_self(); 1849 1850 // We're done with this suspend request, but we have to loop around 1851 // and check again. Eventually we will get SR_lock without a pending 1852 // external suspend request and will be able to mark ourselves as 1853 // exiting. 1854 } 1855 // no more external suspends are allowed at this point 1856 } else { 1857 // before_exit() has already posted JVMTI THREAD_END events 1858 } 1859 1860 // Notify waiters on thread object. This has to be done after exit() is called 1861 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1862 // group should have the destroyed bit set before waiters are notified). 1863 ensure_join(this); 1864 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1865 1866 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1867 // held by this thread must be released. A detach operation must only 1868 // get here if there are no Java frames on the stack. Therefore, any 1869 // owned monitors at this point MUST be JNI-acquired monitors which are 1870 // pre-inflated and in the monitor cache. 1871 // 1872 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1873 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1874 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1875 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1876 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1877 } 1878 1879 // These things needs to be done while we are still a Java Thread. Make sure that thread 1880 // is in a consistent state, in case GC happens 1881 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1882 1883 if (active_handles() != NULL) { 1884 JNIHandleBlock* block = active_handles(); 1885 set_active_handles(NULL); 1886 JNIHandleBlock::release_block(block); 1887 } 1888 1889 if (free_handle_block() != NULL) { 1890 JNIHandleBlock* block = free_handle_block(); 1891 set_free_handle_block(NULL); 1892 JNIHandleBlock::release_block(block); 1893 } 1894 1895 // These have to be removed while this is still a valid thread. 1896 remove_stack_guard_pages(); 1897 1898 if (UseTLAB) { 1899 tlab().make_parsable(true); // retire TLAB 1900 } 1901 1902 if (JvmtiEnv::environments_might_exist()) { 1903 JvmtiExport::cleanup_thread(this); 1904 } 1905 1906 // We must flush any deferred card marks before removing a thread from 1907 // the list of active threads. 1908 Universe::heap()->flush_deferred_store_barrier(this); 1909 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1910 1911#if INCLUDE_ALL_GCS 1912 // We must flush the G1-related buffers before removing a thread 1913 // from the list of active threads. We must do this after any deferred 1914 // card marks have been flushed (above) so that any entries that are 1915 // added to the thread's dirty card queue as a result are not lost. 1916 if (UseG1GC) { 1917 flush_barrier_queues(); 1918 } 1919#endif // INCLUDE_ALL_GCS 1920 1921 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1922 Threads::remove(this); 1923} 1924 1925#if INCLUDE_ALL_GCS 1926// Flush G1-related queues. 1927void JavaThread::flush_barrier_queues() { 1928 satb_mark_queue().flush(); 1929 dirty_card_queue().flush(); 1930} 1931 1932void JavaThread::initialize_queues() { 1933 assert(!SafepointSynchronize::is_at_safepoint(), 1934 "we should not be at a safepoint"); 1935 1936 ObjPtrQueue& satb_queue = satb_mark_queue(); 1937 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1938 // The SATB queue should have been constructed with its active 1939 // field set to false. 1940 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1941 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1942 // If we are creating the thread during a marking cycle, we should 1943 // set the active field of the SATB queue to true. 1944 if (satb_queue_set.is_active()) { 1945 satb_queue.set_active(true); 1946 } 1947 1948 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1949 // The dirty card queue should have been constructed with its 1950 // active field set to true. 1951 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1952} 1953#endif // INCLUDE_ALL_GCS 1954 1955void JavaThread::cleanup_failed_attach_current_thread() { 1956 if (get_thread_profiler() != NULL) { 1957 get_thread_profiler()->disengage(); 1958 ResourceMark rm; 1959 get_thread_profiler()->print(get_thread_name()); 1960 } 1961 1962 if (active_handles() != NULL) { 1963 JNIHandleBlock* block = active_handles(); 1964 set_active_handles(NULL); 1965 JNIHandleBlock::release_block(block); 1966 } 1967 1968 if (free_handle_block() != NULL) { 1969 JNIHandleBlock* block = free_handle_block(); 1970 set_free_handle_block(NULL); 1971 JNIHandleBlock::release_block(block); 1972 } 1973 1974 // These have to be removed while this is still a valid thread. 1975 remove_stack_guard_pages(); 1976 1977 if (UseTLAB) { 1978 tlab().make_parsable(true); // retire TLAB, if any 1979 } 1980 1981#if INCLUDE_ALL_GCS 1982 if (UseG1GC) { 1983 flush_barrier_queues(); 1984 } 1985#endif // INCLUDE_ALL_GCS 1986 1987 Threads::remove(this); 1988 delete this; 1989} 1990 1991 1992 1993 1994JavaThread* JavaThread::active() { 1995 Thread* thread = ThreadLocalStorage::thread(); 1996 assert(thread != NULL, "just checking"); 1997 if (thread->is_Java_thread()) { 1998 return (JavaThread*) thread; 1999 } else { 2000 assert(thread->is_VM_thread(), "this must be a vm thread"); 2001 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2002 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2003 assert(ret->is_Java_thread(), "must be a Java thread"); 2004 return ret; 2005 } 2006} 2007 2008bool JavaThread::is_lock_owned(address adr) const { 2009 if (Thread::is_lock_owned(adr)) return true; 2010 2011 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2012 if (chunk->contains(adr)) return true; 2013 } 2014 2015 return false; 2016} 2017 2018 2019void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2020 chunk->set_next(monitor_chunks()); 2021 set_monitor_chunks(chunk); 2022} 2023 2024void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2025 guarantee(monitor_chunks() != NULL, "must be non empty"); 2026 if (monitor_chunks() == chunk) { 2027 set_monitor_chunks(chunk->next()); 2028 } else { 2029 MonitorChunk* prev = monitor_chunks(); 2030 while (prev->next() != chunk) prev = prev->next(); 2031 prev->set_next(chunk->next()); 2032 } 2033} 2034 2035// JVM support. 2036 2037// Note: this function shouldn't block if it's called in 2038// _thread_in_native_trans state (such as from 2039// check_special_condition_for_native_trans()). 2040void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2041 2042 if (has_last_Java_frame() && has_async_condition()) { 2043 // If we are at a polling page safepoint (not a poll return) 2044 // then we must defer async exception because live registers 2045 // will be clobbered by the exception path. Poll return is 2046 // ok because the call we a returning from already collides 2047 // with exception handling registers and so there is no issue. 2048 // (The exception handling path kills call result registers but 2049 // this is ok since the exception kills the result anyway). 2050 2051 if (is_at_poll_safepoint()) { 2052 // if the code we are returning to has deoptimized we must defer 2053 // the exception otherwise live registers get clobbered on the 2054 // exception path before deoptimization is able to retrieve them. 2055 // 2056 RegisterMap map(this, false); 2057 frame caller_fr = last_frame().sender(&map); 2058 assert(caller_fr.is_compiled_frame(), "what?"); 2059 if (caller_fr.is_deoptimized_frame()) { 2060 if (TraceExceptions) { 2061 ResourceMark rm; 2062 tty->print_cr("deferred async exception at compiled safepoint"); 2063 } 2064 return; 2065 } 2066 } 2067 } 2068 2069 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2070 if (condition == _no_async_condition) { 2071 // Conditions have changed since has_special_runtime_exit_condition() 2072 // was called: 2073 // - if we were here only because of an external suspend request, 2074 // then that was taken care of above (or cancelled) so we are done 2075 // - if we were here because of another async request, then it has 2076 // been cleared between the has_special_runtime_exit_condition() 2077 // and now so again we are done 2078 return; 2079 } 2080 2081 // Check for pending async. exception 2082 if (_pending_async_exception != NULL) { 2083 // Only overwrite an already pending exception, if it is not a threadDeath. 2084 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2085 2086 // We cannot call Exceptions::_throw(...) here because we cannot block 2087 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2088 2089 if (TraceExceptions) { 2090 ResourceMark rm; 2091 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2092 if (has_last_Java_frame() ) { 2093 frame f = last_frame(); 2094 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2095 } 2096 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2097 } 2098 _pending_async_exception = NULL; 2099 clear_has_async_exception(); 2100 } 2101 } 2102 2103 if (check_unsafe_error && 2104 condition == _async_unsafe_access_error && !has_pending_exception()) { 2105 condition = _no_async_condition; // done 2106 switch (thread_state()) { 2107 case _thread_in_vm: 2108 { 2109 JavaThread* THREAD = this; 2110 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2111 } 2112 case _thread_in_native: 2113 { 2114 ThreadInVMfromNative tiv(this); 2115 JavaThread* THREAD = this; 2116 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2117 } 2118 case _thread_in_Java: 2119 { 2120 ThreadInVMfromJava tiv(this); 2121 JavaThread* THREAD = this; 2122 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2123 } 2124 default: 2125 ShouldNotReachHere(); 2126 } 2127 } 2128 2129 assert(condition == _no_async_condition || has_pending_exception() || 2130 (!check_unsafe_error && condition == _async_unsafe_access_error), 2131 "must have handled the async condition, if no exception"); 2132} 2133 2134void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2135 // 2136 // Check for pending external suspend. Internal suspend requests do 2137 // not use handle_special_runtime_exit_condition(). 2138 // If JNIEnv proxies are allowed, don't self-suspend if the target 2139 // thread is not the current thread. In older versions of jdbx, jdbx 2140 // threads could call into the VM with another thread's JNIEnv so we 2141 // can be here operating on behalf of a suspended thread (4432884). 2142 bool do_self_suspend = is_external_suspend_with_lock(); 2143 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2144 // 2145 // Because thread is external suspended the safepoint code will count 2146 // thread as at a safepoint. This can be odd because we can be here 2147 // as _thread_in_Java which would normally transition to _thread_blocked 2148 // at a safepoint. We would like to mark the thread as _thread_blocked 2149 // before calling java_suspend_self like all other callers of it but 2150 // we must then observe proper safepoint protocol. (We can't leave 2151 // _thread_blocked with a safepoint in progress). However we can be 2152 // here as _thread_in_native_trans so we can't use a normal transition 2153 // constructor/destructor pair because they assert on that type of 2154 // transition. We could do something like: 2155 // 2156 // JavaThreadState state = thread_state(); 2157 // set_thread_state(_thread_in_vm); 2158 // { 2159 // ThreadBlockInVM tbivm(this); 2160 // java_suspend_self() 2161 // } 2162 // set_thread_state(_thread_in_vm_trans); 2163 // if (safepoint) block; 2164 // set_thread_state(state); 2165 // 2166 // but that is pretty messy. Instead we just go with the way the 2167 // code has worked before and note that this is the only path to 2168 // java_suspend_self that doesn't put the thread in _thread_blocked 2169 // mode. 2170 2171 frame_anchor()->make_walkable(this); 2172 java_suspend_self(); 2173 2174 // We might be here for reasons in addition to the self-suspend request 2175 // so check for other async requests. 2176 } 2177 2178 if (check_asyncs) { 2179 check_and_handle_async_exceptions(); 2180 } 2181} 2182 2183void JavaThread::send_thread_stop(oop java_throwable) { 2184 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2185 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2186 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2187 2188 // Do not throw asynchronous exceptions against the compiler thread 2189 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2190 if (is_Compiler_thread()) return; 2191 2192 { 2193 // Actually throw the Throwable against the target Thread - however 2194 // only if there is no thread death exception installed already. 2195 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2196 // If the topmost frame is a runtime stub, then we are calling into 2197 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2198 // must deoptimize the caller before continuing, as the compiled exception handler table 2199 // may not be valid 2200 if (has_last_Java_frame()) { 2201 frame f = last_frame(); 2202 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2203 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2204 RegisterMap reg_map(this, UseBiasedLocking); 2205 frame compiled_frame = f.sender(®_map); 2206 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2207 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2208 } 2209 } 2210 } 2211 2212 // Set async. pending exception in thread. 2213 set_pending_async_exception(java_throwable); 2214 2215 if (TraceExceptions) { 2216 ResourceMark rm; 2217 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2218 } 2219 // for AbortVMOnException flag 2220 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2221 } 2222 } 2223 2224 2225 // Interrupt thread so it will wake up from a potential wait() 2226 Thread::interrupt(this); 2227} 2228 2229// External suspension mechanism. 2230// 2231// Tell the VM to suspend a thread when ever it knows that it does not hold on 2232// to any VM_locks and it is at a transition 2233// Self-suspension will happen on the transition out of the vm. 2234// Catch "this" coming in from JNIEnv pointers when the thread has been freed 2235// 2236// Guarantees on return: 2237// + Target thread will not execute any new bytecode (that's why we need to 2238// force a safepoint) 2239// + Target thread will not enter any new monitors 2240// 2241void JavaThread::java_suspend() { 2242 { MutexLocker mu(Threads_lock); 2243 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2244 return; 2245 } 2246 } 2247 2248 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2249 if (!is_external_suspend()) { 2250 // a racing resume has cancelled us; bail out now 2251 return; 2252 } 2253 2254 // suspend is done 2255 uint32_t debug_bits = 0; 2256 // Warning: is_ext_suspend_completed() may temporarily drop the 2257 // SR_lock to allow the thread to reach a stable thread state if 2258 // it is currently in a transient thread state. 2259 if (is_ext_suspend_completed(false /* !called_by_wait */, 2260 SuspendRetryDelay, &debug_bits) ) { 2261 return; 2262 } 2263 } 2264 2265 VM_ForceSafepoint vm_suspend; 2266 VMThread::execute(&vm_suspend); 2267} 2268 2269// Part II of external suspension. 2270// A JavaThread self suspends when it detects a pending external suspend 2271// request. This is usually on transitions. It is also done in places 2272// where continuing to the next transition would surprise the caller, 2273// e.g., monitor entry. 2274// 2275// Returns the number of times that the thread self-suspended. 2276// 2277// Note: DO NOT call java_suspend_self() when you just want to block current 2278// thread. java_suspend_self() is the second stage of cooperative 2279// suspension for external suspend requests and should only be used 2280// to complete an external suspend request. 2281// 2282int JavaThread::java_suspend_self() { 2283 int ret = 0; 2284 2285 // we are in the process of exiting so don't suspend 2286 if (is_exiting()) { 2287 clear_external_suspend(); 2288 return ret; 2289 } 2290 2291 assert(_anchor.walkable() || 2292 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2293 "must have walkable stack"); 2294 2295 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2296 2297 assert(!this->is_ext_suspended(), 2298 "a thread trying to self-suspend should not already be suspended"); 2299 2300 if (this->is_suspend_equivalent()) { 2301 // If we are self-suspending as a result of the lifting of a 2302 // suspend equivalent condition, then the suspend_equivalent 2303 // flag is not cleared until we set the ext_suspended flag so 2304 // that wait_for_ext_suspend_completion() returns consistent 2305 // results. 2306 this->clear_suspend_equivalent(); 2307 } 2308 2309 // A racing resume may have cancelled us before we grabbed SR_lock 2310 // above. Or another external suspend request could be waiting for us 2311 // by the time we return from SR_lock()->wait(). The thread 2312 // that requested the suspension may already be trying to walk our 2313 // stack and if we return now, we can change the stack out from under 2314 // it. This would be a "bad thing (TM)" and cause the stack walker 2315 // to crash. We stay self-suspended until there are no more pending 2316 // external suspend requests. 2317 while (is_external_suspend()) { 2318 ret++; 2319 this->set_ext_suspended(); 2320 2321 // _ext_suspended flag is cleared by java_resume() 2322 while (is_ext_suspended()) { 2323 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2324 } 2325 } 2326 2327 return ret; 2328} 2329 2330#ifdef ASSERT 2331// verify the JavaThread has not yet been published in the Threads::list, and 2332// hence doesn't need protection from concurrent access at this stage 2333void JavaThread::verify_not_published() { 2334 if (!Threads_lock->owned_by_self()) { 2335 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2336 assert( !Threads::includes(this), 2337 "java thread shouldn't have been published yet!"); 2338 } 2339 else { 2340 assert( !Threads::includes(this), 2341 "java thread shouldn't have been published yet!"); 2342 } 2343} 2344#endif 2345 2346// Slow path when the native==>VM/Java barriers detect a safepoint is in 2347// progress or when _suspend_flags is non-zero. 2348// Current thread needs to self-suspend if there is a suspend request and/or 2349// block if a safepoint is in progress. 2350// Async exception ISN'T checked. 2351// Note only the ThreadInVMfromNative transition can call this function 2352// directly and when thread state is _thread_in_native_trans 2353void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2354 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2355 2356 JavaThread *curJT = JavaThread::current(); 2357 bool do_self_suspend = thread->is_external_suspend(); 2358 2359 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2360 2361 // If JNIEnv proxies are allowed, don't self-suspend if the target 2362 // thread is not the current thread. In older versions of jdbx, jdbx 2363 // threads could call into the VM with another thread's JNIEnv so we 2364 // can be here operating on behalf of a suspended thread (4432884). 2365 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2366 JavaThreadState state = thread->thread_state(); 2367 2368 // We mark this thread_blocked state as a suspend-equivalent so 2369 // that a caller to is_ext_suspend_completed() won't be confused. 2370 // The suspend-equivalent state is cleared by java_suspend_self(). 2371 thread->set_suspend_equivalent(); 2372 2373 // If the safepoint code sees the _thread_in_native_trans state, it will 2374 // wait until the thread changes to other thread state. There is no 2375 // guarantee on how soon we can obtain the SR_lock and complete the 2376 // self-suspend request. It would be a bad idea to let safepoint wait for 2377 // too long. Temporarily change the state to _thread_blocked to 2378 // let the VM thread know that this thread is ready for GC. The problem 2379 // of changing thread state is that safepoint could happen just after 2380 // java_suspend_self() returns after being resumed, and VM thread will 2381 // see the _thread_blocked state. We must check for safepoint 2382 // after restoring the state and make sure we won't leave while a safepoint 2383 // is in progress. 2384 thread->set_thread_state(_thread_blocked); 2385 thread->java_suspend_self(); 2386 thread->set_thread_state(state); 2387 // Make sure new state is seen by VM thread 2388 if (os::is_MP()) { 2389 if (UseMembar) { 2390 // Force a fence between the write above and read below 2391 OrderAccess::fence(); 2392 } else { 2393 // Must use this rather than serialization page in particular on Windows 2394 InterfaceSupport::serialize_memory(thread); 2395 } 2396 } 2397 } 2398 2399 if (SafepointSynchronize::do_call_back()) { 2400 // If we are safepointing, then block the caller which may not be 2401 // the same as the target thread (see above). 2402 SafepointSynchronize::block(curJT); 2403 } 2404 2405 if (thread->is_deopt_suspend()) { 2406 thread->clear_deopt_suspend(); 2407 RegisterMap map(thread, false); 2408 frame f = thread->last_frame(); 2409 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2410 f = f.sender(&map); 2411 } 2412 if (f.id() == thread->must_deopt_id()) { 2413 thread->clear_must_deopt_id(); 2414 f.deoptimize(thread); 2415 } else { 2416 fatal("missed deoptimization!"); 2417 } 2418 } 2419} 2420 2421// Slow path when the native==>VM/Java barriers detect a safepoint is in 2422// progress or when _suspend_flags is non-zero. 2423// Current thread needs to self-suspend if there is a suspend request and/or 2424// block if a safepoint is in progress. 2425// Also check for pending async exception (not including unsafe access error). 2426// Note only the native==>VM/Java barriers can call this function and when 2427// thread state is _thread_in_native_trans. 2428void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2429 check_safepoint_and_suspend_for_native_trans(thread); 2430 2431 if (thread->has_async_exception()) { 2432 // We are in _thread_in_native_trans state, don't handle unsafe 2433 // access error since that may block. 2434 thread->check_and_handle_async_exceptions(false); 2435 } 2436} 2437 2438// This is a variant of the normal 2439// check_special_condition_for_native_trans with slightly different 2440// semantics for use by critical native wrappers. It does all the 2441// normal checks but also performs the transition back into 2442// thread_in_Java state. This is required so that critical natives 2443// can potentially block and perform a GC if they are the last thread 2444// exiting the GC_locker. 2445void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2446 check_special_condition_for_native_trans(thread); 2447 2448 // Finish the transition 2449 thread->set_thread_state(_thread_in_Java); 2450 2451 if (thread->do_critical_native_unlock()) { 2452 ThreadInVMfromJavaNoAsyncException tiv(thread); 2453 GC_locker::unlock_critical(thread); 2454 thread->clear_critical_native_unlock(); 2455 } 2456} 2457 2458// We need to guarantee the Threads_lock here, since resumes are not 2459// allowed during safepoint synchronization 2460// Can only resume from an external suspension 2461void JavaThread::java_resume() { 2462 assert_locked_or_safepoint(Threads_lock); 2463 2464 // Sanity check: thread is gone, has started exiting or the thread 2465 // was not externally suspended. 2466 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2467 return; 2468 } 2469 2470 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2471 2472 clear_external_suspend(); 2473 2474 if (is_ext_suspended()) { 2475 clear_ext_suspended(); 2476 SR_lock()->notify_all(); 2477 } 2478} 2479 2480void JavaThread::create_stack_guard_pages() { 2481 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2482 address low_addr = stack_base() - stack_size(); 2483 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2484 2485 int allocate = os::allocate_stack_guard_pages(); 2486 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2487 2488 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2489 warning("Attempt to allocate stack guard pages failed."); 2490 return; 2491 } 2492 2493 if (os::guard_memory((char *) low_addr, len)) { 2494 _stack_guard_state = stack_guard_enabled; 2495 } else { 2496 warning("Attempt to protect stack guard pages failed."); 2497 if (os::uncommit_memory((char *) low_addr, len)) { 2498 warning("Attempt to deallocate stack guard pages failed."); 2499 } 2500 } 2501} 2502 2503void JavaThread::remove_stack_guard_pages() { 2504 assert(Thread::current() == this, "from different thread"); 2505 if (_stack_guard_state == stack_guard_unused) return; 2506 address low_addr = stack_base() - stack_size(); 2507 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2508 2509 if (os::allocate_stack_guard_pages()) { 2510 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2511 _stack_guard_state = stack_guard_unused; 2512 } else { 2513 warning("Attempt to deallocate stack guard pages failed."); 2514 } 2515 } else { 2516 if (_stack_guard_state == stack_guard_unused) return; 2517 if (os::unguard_memory((char *) low_addr, len)) { 2518 _stack_guard_state = stack_guard_unused; 2519 } else { 2520 warning("Attempt to unprotect stack guard pages failed."); 2521 } 2522 } 2523} 2524 2525void JavaThread::enable_stack_yellow_zone() { 2526 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2527 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2528 2529 // The base notation is from the stacks point of view, growing downward. 2530 // We need to adjust it to work correctly with guard_memory() 2531 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2532 2533 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2534 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2535 2536 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2537 _stack_guard_state = stack_guard_enabled; 2538 } else { 2539 warning("Attempt to guard stack yellow zone failed."); 2540 } 2541 enable_register_stack_guard(); 2542} 2543 2544void JavaThread::disable_stack_yellow_zone() { 2545 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2546 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2547 2548 // Simply return if called for a thread that does not use guard pages. 2549 if (_stack_guard_state == stack_guard_unused) return; 2550 2551 // The base notation is from the stacks point of view, growing downward. 2552 // We need to adjust it to work correctly with guard_memory() 2553 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2554 2555 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2556 _stack_guard_state = stack_guard_yellow_disabled; 2557 } else { 2558 warning("Attempt to unguard stack yellow zone failed."); 2559 } 2560 disable_register_stack_guard(); 2561} 2562 2563void JavaThread::enable_stack_red_zone() { 2564 // The base notation is from the stacks point of view, growing downward. 2565 // We need to adjust it to work correctly with guard_memory() 2566 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2567 address base = stack_red_zone_base() - stack_red_zone_size(); 2568 2569 guarantee(base < stack_base(),"Error calculating stack red zone"); 2570 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2571 2572 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2573 warning("Attempt to guard stack red zone failed."); 2574 } 2575} 2576 2577void JavaThread::disable_stack_red_zone() { 2578 // The base notation is from the stacks point of view, growing downward. 2579 // We need to adjust it to work correctly with guard_memory() 2580 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2581 address base = stack_red_zone_base() - stack_red_zone_size(); 2582 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2583 warning("Attempt to unguard stack red zone failed."); 2584 } 2585} 2586 2587void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2588 // ignore is there is no stack 2589 if (!has_last_Java_frame()) return; 2590 // traverse the stack frames. Starts from top frame. 2591 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2592 frame* fr = fst.current(); 2593 f(fr, fst.register_map()); 2594 } 2595} 2596 2597 2598#ifndef PRODUCT 2599// Deoptimization 2600// Function for testing deoptimization 2601void JavaThread::deoptimize() { 2602 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2603 StackFrameStream fst(this, UseBiasedLocking); 2604 bool deopt = false; // Dump stack only if a deopt actually happens. 2605 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2606 // Iterate over all frames in the thread and deoptimize 2607 for(; !fst.is_done(); fst.next()) { 2608 if(fst.current()->can_be_deoptimized()) { 2609 2610 if (only_at) { 2611 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2612 // consists of comma or carriage return separated numbers so 2613 // search for the current bci in that string. 2614 address pc = fst.current()->pc(); 2615 nmethod* nm = (nmethod*) fst.current()->cb(); 2616 ScopeDesc* sd = nm->scope_desc_at( pc); 2617 char buffer[8]; 2618 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2619 size_t len = strlen(buffer); 2620 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2621 while (found != NULL) { 2622 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2623 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2624 // Check that the bci found is bracketed by terminators. 2625 break; 2626 } 2627 found = strstr(found + 1, buffer); 2628 } 2629 if (!found) { 2630 continue; 2631 } 2632 } 2633 2634 if (DebugDeoptimization && !deopt) { 2635 deopt = true; // One-time only print before deopt 2636 tty->print_cr("[BEFORE Deoptimization]"); 2637 trace_frames(); 2638 trace_stack(); 2639 } 2640 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2641 } 2642 } 2643 2644 if (DebugDeoptimization && deopt) { 2645 tty->print_cr("[AFTER Deoptimization]"); 2646 trace_frames(); 2647 } 2648} 2649 2650 2651// Make zombies 2652void JavaThread::make_zombies() { 2653 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2654 if (fst.current()->can_be_deoptimized()) { 2655 // it is a Java nmethod 2656 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2657 nm->make_not_entrant(); 2658 } 2659 } 2660} 2661#endif // PRODUCT 2662 2663 2664void JavaThread::deoptimized_wrt_marked_nmethods() { 2665 if (!has_last_Java_frame()) return; 2666 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2667 StackFrameStream fst(this, UseBiasedLocking); 2668 for(; !fst.is_done(); fst.next()) { 2669 if (fst.current()->should_be_deoptimized()) { 2670 if (LogCompilation && xtty != NULL) { 2671 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2672 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2673 this->name(), nm != NULL ? nm->compile_id() : -1); 2674 } 2675 2676 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2677 } 2678 } 2679} 2680 2681 2682// GC support 2683static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2684 2685void JavaThread::gc_epilogue() { 2686 frames_do(frame_gc_epilogue); 2687} 2688 2689 2690static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2691 2692void JavaThread::gc_prologue() { 2693 frames_do(frame_gc_prologue); 2694} 2695 2696// If the caller is a NamedThread, then remember, in the current scope, 2697// the given JavaThread in its _processed_thread field. 2698class RememberProcessedThread: public StackObj { 2699 NamedThread* _cur_thr; 2700public: 2701 RememberProcessedThread(JavaThread* jthr) { 2702 Thread* thread = Thread::current(); 2703 if (thread->is_Named_thread()) { 2704 _cur_thr = (NamedThread *)thread; 2705 _cur_thr->set_processed_thread(jthr); 2706 } else { 2707 _cur_thr = NULL; 2708 } 2709 } 2710 2711 ~RememberProcessedThread() { 2712 if (_cur_thr) { 2713 _cur_thr->set_processed_thread(NULL); 2714 } 2715 } 2716}; 2717 2718void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 2719 // Verify that the deferred card marks have been flushed. 2720 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2721 2722 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2723 // since there may be more than one thread using each ThreadProfiler. 2724 2725 // Traverse the GCHandles 2726 Thread::oops_do(f, cld_f, cf); 2727 2728 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2729 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2730 2731 if (has_last_Java_frame()) { 2732 // Record JavaThread to GC thread 2733 RememberProcessedThread rpt(this); 2734 2735 // Traverse the privileged stack 2736 if (_privileged_stack_top != NULL) { 2737 _privileged_stack_top->oops_do(f); 2738 } 2739 2740 // traverse the registered growable array 2741 if (_array_for_gc != NULL) { 2742 for (int index = 0; index < _array_for_gc->length(); index++) { 2743 f->do_oop(_array_for_gc->adr_at(index)); 2744 } 2745 } 2746 2747 // Traverse the monitor chunks 2748 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2749 chunk->oops_do(f); 2750 } 2751 2752 // Traverse the execution stack 2753 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2754 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2755 } 2756 } 2757 2758 // callee_target is never live across a gc point so NULL it here should 2759 // it still contain a methdOop. 2760 2761 set_callee_target(NULL); 2762 2763 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2764 // If we have deferred set_locals there might be oops waiting to be 2765 // written 2766 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2767 if (list != NULL) { 2768 for (int i = 0; i < list->length(); i++) { 2769 list->at(i)->oops_do(f); 2770 } 2771 } 2772 2773 // Traverse instance variables at the end since the GC may be moving things 2774 // around using this function 2775 f->do_oop((oop*) &_threadObj); 2776 f->do_oop((oop*) &_vm_result); 2777 f->do_oop((oop*) &_exception_oop); 2778 f->do_oop((oop*) &_pending_async_exception); 2779 2780 if (jvmti_thread_state() != NULL) { 2781 jvmti_thread_state()->oops_do(f); 2782 } 2783} 2784 2785void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2786 Thread::nmethods_do(cf); // (super method is a no-op) 2787 2788 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2789 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2790 2791 if (has_last_Java_frame()) { 2792 // Traverse the execution stack 2793 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2794 fst.current()->nmethods_do(cf); 2795 } 2796 } 2797} 2798 2799void JavaThread::metadata_do(void f(Metadata*)) { 2800 Thread::metadata_do(f); 2801 if (has_last_Java_frame()) { 2802 // Traverse the execution stack to call f() on the methods in the stack 2803 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2804 fst.current()->metadata_do(f); 2805 } 2806 } else if (is_Compiler_thread()) { 2807 // need to walk ciMetadata in current compile tasks to keep alive. 2808 CompilerThread* ct = (CompilerThread*)this; 2809 if (ct->env() != NULL) { 2810 ct->env()->metadata_do(f); 2811 } 2812 } 2813} 2814 2815// Printing 2816const char* _get_thread_state_name(JavaThreadState _thread_state) { 2817 switch (_thread_state) { 2818 case _thread_uninitialized: return "_thread_uninitialized"; 2819 case _thread_new: return "_thread_new"; 2820 case _thread_new_trans: return "_thread_new_trans"; 2821 case _thread_in_native: return "_thread_in_native"; 2822 case _thread_in_native_trans: return "_thread_in_native_trans"; 2823 case _thread_in_vm: return "_thread_in_vm"; 2824 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2825 case _thread_in_Java: return "_thread_in_Java"; 2826 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2827 case _thread_blocked: return "_thread_blocked"; 2828 case _thread_blocked_trans: return "_thread_blocked_trans"; 2829 default: return "unknown thread state"; 2830 } 2831} 2832 2833#ifndef PRODUCT 2834void JavaThread::print_thread_state_on(outputStream *st) const { 2835 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2836}; 2837void JavaThread::print_thread_state() const { 2838 print_thread_state_on(tty); 2839}; 2840#endif // PRODUCT 2841 2842// Called by Threads::print() for VM_PrintThreads operation 2843void JavaThread::print_on(outputStream *st) const { 2844 st->print("\"%s\" ", get_thread_name()); 2845 oop thread_oop = threadObj(); 2846 if (thread_oop != NULL) { 2847 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2848 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2849 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2850 } 2851 Thread::print_on(st); 2852 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2853 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2854 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2855 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2856 } 2857#ifndef PRODUCT 2858 print_thread_state_on(st); 2859 _safepoint_state->print_on(st); 2860#endif // PRODUCT 2861} 2862 2863// Called by fatal error handler. The difference between this and 2864// JavaThread::print() is that we can't grab lock or allocate memory. 2865void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2866 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2867 oop thread_obj = threadObj(); 2868 if (thread_obj != NULL) { 2869 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2870 } 2871 st->print(" ["); 2872 st->print("%s", _get_thread_state_name(_thread_state)); 2873 if (osthread()) { 2874 st->print(", id=%d", osthread()->thread_id()); 2875 } 2876 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2877 _stack_base - _stack_size, _stack_base); 2878 st->print("]"); 2879 return; 2880} 2881 2882// Verification 2883 2884static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2885 2886void JavaThread::verify() { 2887 // Verify oops in the thread. 2888 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2889 2890 // Verify the stack frames. 2891 frames_do(frame_verify); 2892} 2893 2894// CR 6300358 (sub-CR 2137150) 2895// Most callers of this method assume that it can't return NULL but a 2896// thread may not have a name whilst it is in the process of attaching to 2897// the VM - see CR 6412693, and there are places where a JavaThread can be 2898// seen prior to having it's threadObj set (eg JNI attaching threads and 2899// if vm exit occurs during initialization). These cases can all be accounted 2900// for such that this method never returns NULL. 2901const char* JavaThread::get_thread_name() const { 2902#ifdef ASSERT 2903 // early safepoints can hit while current thread does not yet have TLS 2904 if (!SafepointSynchronize::is_at_safepoint()) { 2905 Thread *cur = Thread::current(); 2906 if (!(cur->is_Java_thread() && cur == this)) { 2907 // Current JavaThreads are allowed to get their own name without 2908 // the Threads_lock. 2909 assert_locked_or_safepoint(Threads_lock); 2910 } 2911 } 2912#endif // ASSERT 2913 return get_thread_name_string(); 2914} 2915 2916// Returns a non-NULL representation of this thread's name, or a suitable 2917// descriptive string if there is no set name 2918const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2919 const char* name_str; 2920 oop thread_obj = threadObj(); 2921 if (thread_obj != NULL) { 2922 typeArrayOop name = java_lang_Thread::name(thread_obj); 2923 if (name != NULL) { 2924 if (buf == NULL) { 2925 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2926 } 2927 else { 2928 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2929 } 2930 } 2931 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2932 name_str = "<no-name - thread is attaching>"; 2933 } 2934 else { 2935 name_str = Thread::name(); 2936 } 2937 } 2938 else { 2939 name_str = Thread::name(); 2940 } 2941 assert(name_str != NULL, "unexpected NULL thread name"); 2942 return name_str; 2943} 2944 2945 2946const char* JavaThread::get_threadgroup_name() const { 2947 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2948 oop thread_obj = threadObj(); 2949 if (thread_obj != NULL) { 2950 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2951 if (thread_group != NULL) { 2952 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2953 // ThreadGroup.name can be null 2954 if (name != NULL) { 2955 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2956 return str; 2957 } 2958 } 2959 } 2960 return NULL; 2961} 2962 2963const char* JavaThread::get_parent_name() const { 2964 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2965 oop thread_obj = threadObj(); 2966 if (thread_obj != NULL) { 2967 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2968 if (thread_group != NULL) { 2969 oop parent = java_lang_ThreadGroup::parent(thread_group); 2970 if (parent != NULL) { 2971 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2972 // ThreadGroup.name can be null 2973 if (name != NULL) { 2974 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2975 return str; 2976 } 2977 } 2978 } 2979 } 2980 return NULL; 2981} 2982 2983ThreadPriority JavaThread::java_priority() const { 2984 oop thr_oop = threadObj(); 2985 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2986 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2987 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2988 return priority; 2989} 2990 2991void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2992 2993 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2994 // Link Java Thread object <-> C++ Thread 2995 2996 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2997 // and put it into a new Handle. The Handle "thread_oop" can then 2998 // be used to pass the C++ thread object to other methods. 2999 3000 // Set the Java level thread object (jthread) field of the 3001 // new thread (a JavaThread *) to C++ thread object using the 3002 // "thread_oop" handle. 3003 3004 // Set the thread field (a JavaThread *) of the 3005 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3006 3007 Handle thread_oop(Thread::current(), 3008 JNIHandles::resolve_non_null(jni_thread)); 3009 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3010 "must be initialized"); 3011 set_threadObj(thread_oop()); 3012 java_lang_Thread::set_thread(thread_oop(), this); 3013 3014 if (prio == NoPriority) { 3015 prio = java_lang_Thread::priority(thread_oop()); 3016 assert(prio != NoPriority, "A valid priority should be present"); 3017 } 3018 3019 // Push the Java priority down to the native thread; needs Threads_lock 3020 Thread::set_priority(this, prio); 3021 3022 // Add the new thread to the Threads list and set it in motion. 3023 // We must have threads lock in order to call Threads::add. 3024 // It is crucial that we do not block before the thread is 3025 // added to the Threads list for if a GC happens, then the java_thread oop 3026 // will not be visited by GC. 3027 Threads::add(this); 3028} 3029 3030oop JavaThread::current_park_blocker() { 3031 // Support for JSR-166 locks 3032 oop thread_oop = threadObj(); 3033 if (thread_oop != NULL && 3034 JDK_Version::current().supports_thread_park_blocker()) { 3035 return java_lang_Thread::park_blocker(thread_oop); 3036 } 3037 return NULL; 3038} 3039 3040 3041void JavaThread::print_stack_on(outputStream* st) { 3042 if (!has_last_Java_frame()) return; 3043 ResourceMark rm; 3044 HandleMark hm; 3045 3046 RegisterMap reg_map(this); 3047 vframe* start_vf = last_java_vframe(®_map); 3048 int count = 0; 3049 for (vframe* f = start_vf; f; f = f->sender() ) { 3050 if (f->is_java_frame()) { 3051 javaVFrame* jvf = javaVFrame::cast(f); 3052 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3053 3054 // Print out lock information 3055 if (JavaMonitorsInStackTrace) { 3056 jvf->print_lock_info_on(st, count); 3057 } 3058 } else { 3059 // Ignore non-Java frames 3060 } 3061 3062 // Bail-out case for too deep stacks 3063 count++; 3064 if (MaxJavaStackTraceDepth == count) return; 3065 } 3066} 3067 3068 3069// JVMTI PopFrame support 3070void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3071 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3072 if (in_bytes(size_in_bytes) != 0) { 3073 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3074 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3075 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3076 } 3077} 3078 3079void* JavaThread::popframe_preserved_args() { 3080 return _popframe_preserved_args; 3081} 3082 3083ByteSize JavaThread::popframe_preserved_args_size() { 3084 return in_ByteSize(_popframe_preserved_args_size); 3085} 3086 3087WordSize JavaThread::popframe_preserved_args_size_in_words() { 3088 int sz = in_bytes(popframe_preserved_args_size()); 3089 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3090 return in_WordSize(sz / wordSize); 3091} 3092 3093void JavaThread::popframe_free_preserved_args() { 3094 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3095 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3096 _popframe_preserved_args = NULL; 3097 _popframe_preserved_args_size = 0; 3098} 3099 3100#ifndef PRODUCT 3101 3102void JavaThread::trace_frames() { 3103 tty->print_cr("[Describe stack]"); 3104 int frame_no = 1; 3105 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3106 tty->print(" %d. ", frame_no++); 3107 fst.current()->print_value_on(tty,this); 3108 tty->cr(); 3109 } 3110} 3111 3112class PrintAndVerifyOopClosure: public OopClosure { 3113 protected: 3114 template <class T> inline void do_oop_work(T* p) { 3115 oop obj = oopDesc::load_decode_heap_oop(p); 3116 if (obj == NULL) return; 3117 tty->print(INTPTR_FORMAT ": ", p); 3118 if (obj->is_oop_or_null()) { 3119 if (obj->is_objArray()) { 3120 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3121 } else { 3122 obj->print(); 3123 } 3124 } else { 3125 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3126 } 3127 tty->cr(); 3128 } 3129 public: 3130 virtual void do_oop(oop* p) { do_oop_work(p); } 3131 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3132}; 3133 3134 3135static void oops_print(frame* f, const RegisterMap *map) { 3136 PrintAndVerifyOopClosure print; 3137 f->print_value(); 3138 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3139} 3140 3141// Print our all the locations that contain oops and whether they are 3142// valid or not. This useful when trying to find the oldest frame 3143// where an oop has gone bad since the frame walk is from youngest to 3144// oldest. 3145void JavaThread::trace_oops() { 3146 tty->print_cr("[Trace oops]"); 3147 frames_do(oops_print); 3148} 3149 3150 3151#ifdef ASSERT 3152// Print or validate the layout of stack frames 3153void JavaThread::print_frame_layout(int depth, bool validate_only) { 3154 ResourceMark rm; 3155 PRESERVE_EXCEPTION_MARK; 3156 FrameValues values; 3157 int frame_no = 0; 3158 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3159 fst.current()->describe(values, ++frame_no); 3160 if (depth == frame_no) break; 3161 } 3162 if (validate_only) { 3163 values.validate(); 3164 } else { 3165 tty->print_cr("[Describe stack layout]"); 3166 values.print(this); 3167 } 3168} 3169#endif 3170 3171void JavaThread::trace_stack_from(vframe* start_vf) { 3172 ResourceMark rm; 3173 int vframe_no = 1; 3174 for (vframe* f = start_vf; f; f = f->sender() ) { 3175 if (f->is_java_frame()) { 3176 javaVFrame::cast(f)->print_activation(vframe_no++); 3177 } else { 3178 f->print(); 3179 } 3180 if (vframe_no > StackPrintLimit) { 3181 tty->print_cr("...<more frames>..."); 3182 return; 3183 } 3184 } 3185} 3186 3187 3188void JavaThread::trace_stack() { 3189 if (!has_last_Java_frame()) return; 3190 ResourceMark rm; 3191 HandleMark hm; 3192 RegisterMap reg_map(this); 3193 trace_stack_from(last_java_vframe(®_map)); 3194} 3195 3196 3197#endif // PRODUCT 3198 3199 3200javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3201 assert(reg_map != NULL, "a map must be given"); 3202 frame f = last_frame(); 3203 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3204 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3205 } 3206 return NULL; 3207} 3208 3209 3210Klass* JavaThread::security_get_caller_class(int depth) { 3211 vframeStream vfst(this); 3212 vfst.security_get_caller_frame(depth); 3213 if (!vfst.at_end()) { 3214 return vfst.method()->method_holder(); 3215 } 3216 return NULL; 3217} 3218 3219static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3220 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3221 CompileBroker::compiler_thread_loop(); 3222} 3223 3224// Create a CompilerThread 3225CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3226: JavaThread(&compiler_thread_entry) { 3227 _env = NULL; 3228 _log = NULL; 3229 _task = NULL; 3230 _queue = queue; 3231 _counters = counters; 3232 _buffer_blob = NULL; 3233 _scanned_nmethod = NULL; 3234 3235#ifndef PRODUCT 3236 _ideal_graph_printer = NULL; 3237#endif 3238} 3239 3240void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 3241 JavaThread::oops_do(f, cld_f, cf); 3242 if (_scanned_nmethod != NULL && cf != NULL) { 3243 // Safepoints can occur when the sweeper is scanning an nmethod so 3244 // process it here to make sure it isn't unloaded in the middle of 3245 // a scan. 3246 cf->do_code_blob(_scanned_nmethod); 3247 } 3248} 3249 3250// ======= Threads ======== 3251 3252// The Threads class links together all active threads, and provides 3253// operations over all threads. It is protected by its own Mutex 3254// lock, which is also used in other contexts to protect thread 3255// operations from having the thread being operated on from exiting 3256// and going away unexpectedly (e.g., safepoint synchronization) 3257 3258JavaThread* Threads::_thread_list = NULL; 3259int Threads::_number_of_threads = 0; 3260int Threads::_number_of_non_daemon_threads = 0; 3261int Threads::_return_code = 0; 3262size_t JavaThread::_stack_size_at_create = 0; 3263#ifdef ASSERT 3264bool Threads::_vm_complete = false; 3265#endif 3266 3267// All JavaThreads 3268#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3269 3270void os_stream(); 3271 3272// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3273void Threads::threads_do(ThreadClosure* tc) { 3274 assert_locked_or_safepoint(Threads_lock); 3275 // ALL_JAVA_THREADS iterates through all JavaThreads 3276 ALL_JAVA_THREADS(p) { 3277 tc->do_thread(p); 3278 } 3279 // Someday we could have a table or list of all non-JavaThreads. 3280 // For now, just manually iterate through them. 3281 tc->do_thread(VMThread::vm_thread()); 3282 Universe::heap()->gc_threads_do(tc); 3283 WatcherThread *wt = WatcherThread::watcher_thread(); 3284 // Strictly speaking, the following NULL check isn't sufficient to make sure 3285 // the data for WatcherThread is still valid upon being examined. However, 3286 // considering that WatchThread terminates when the VM is on the way to 3287 // exit at safepoint, the chance of the above is extremely small. The right 3288 // way to prevent termination of WatcherThread would be to acquire 3289 // Terminator_lock, but we can't do that without violating the lock rank 3290 // checking in some cases. 3291 if (wt != NULL) 3292 tc->do_thread(wt); 3293 3294 // If CompilerThreads ever become non-JavaThreads, add them here 3295} 3296 3297jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3298 3299 extern void JDK_Version_init(); 3300 3301 // Check version 3302 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3303 3304 // Initialize the output stream module 3305 ostream_init(); 3306 3307 // Process java launcher properties. 3308 Arguments::process_sun_java_launcher_properties(args); 3309 3310 // Initialize the os module before using TLS 3311 os::init(); 3312 3313 // Initialize system properties. 3314 Arguments::init_system_properties(); 3315 3316 // So that JDK version can be used as a discrimintor when parsing arguments 3317 JDK_Version_init(); 3318 3319 // Update/Initialize System properties after JDK version number is known 3320 Arguments::init_version_specific_system_properties(); 3321 3322 // Parse arguments 3323 jint parse_result = Arguments::parse(args); 3324 if (parse_result != JNI_OK) return parse_result; 3325 3326 if (PauseAtStartup) { 3327 os::pause(); 3328 } 3329 3330#ifndef USDT2 3331 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3332#else /* USDT2 */ 3333 HOTSPOT_VM_INIT_BEGIN(); 3334#endif /* USDT2 */ 3335 3336 // Record VM creation timing statistics 3337 TraceVmCreationTime create_vm_timer; 3338 create_vm_timer.start(); 3339 3340 // Timing (must come after argument parsing) 3341 TraceTime timer("Create VM", TraceStartupTime); 3342 3343 // Initialize the os module after parsing the args 3344 jint os_init_2_result = os::init_2(); 3345 if (os_init_2_result != JNI_OK) return os_init_2_result; 3346 3347 jint adjust_after_os_result = Arguments::adjust_after_os(); 3348 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3349 3350 // intialize TLS 3351 ThreadLocalStorage::init(); 3352 3353 // Bootstrap native memory tracking, so it can start recording memory 3354 // activities before worker thread is started. This is the first phase 3355 // of bootstrapping, VM is currently running in single-thread mode. 3356 MemTracker::bootstrap_single_thread(); 3357 3358 // Initialize output stream logging 3359 ostream_init_log(); 3360 3361 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3362 // Must be before create_vm_init_agents() 3363 if (Arguments::init_libraries_at_startup()) { 3364 convert_vm_init_libraries_to_agents(); 3365 } 3366 3367 // Launch -agentlib/-agentpath and converted -Xrun agents 3368 if (Arguments::init_agents_at_startup()) { 3369 create_vm_init_agents(); 3370 } 3371 3372 // Initialize Threads state 3373 _thread_list = NULL; 3374 _number_of_threads = 0; 3375 _number_of_non_daemon_threads = 0; 3376 3377 // Initialize global data structures and create system classes in heap 3378 vm_init_globals(); 3379 3380 // Attach the main thread to this os thread 3381 JavaThread* main_thread = new JavaThread(); 3382 main_thread->set_thread_state(_thread_in_vm); 3383 // must do this before set_active_handles and initialize_thread_local_storage 3384 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3385 // change the stack size recorded here to one based on the java thread 3386 // stacksize. This adjusted size is what is used to figure the placement 3387 // of the guard pages. 3388 main_thread->record_stack_base_and_size(); 3389 main_thread->initialize_thread_local_storage(); 3390 3391 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3392 3393 if (!main_thread->set_as_starting_thread()) { 3394 vm_shutdown_during_initialization( 3395 "Failed necessary internal allocation. Out of swap space"); 3396 delete main_thread; 3397 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3398 return JNI_ENOMEM; 3399 } 3400 3401 // Enable guard page *after* os::create_main_thread(), otherwise it would 3402 // crash Linux VM, see notes in os_linux.cpp. 3403 main_thread->create_stack_guard_pages(); 3404 3405 // Initialize Java-Level synchronization subsystem 3406 ObjectMonitor::Initialize() ; 3407 3408 // Second phase of bootstrapping, VM is about entering multi-thread mode 3409 MemTracker::bootstrap_multi_thread(); 3410 3411 // Initialize global modules 3412 jint status = init_globals(); 3413 if (status != JNI_OK) { 3414 delete main_thread; 3415 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3416 return status; 3417 } 3418 3419 // Should be done after the heap is fully created 3420 main_thread->cache_global_variables(); 3421 3422 HandleMark hm; 3423 3424 { MutexLocker mu(Threads_lock); 3425 Threads::add(main_thread); 3426 } 3427 3428 // Any JVMTI raw monitors entered in onload will transition into 3429 // real raw monitor. VM is setup enough here for raw monitor enter. 3430 JvmtiExport::transition_pending_onload_raw_monitors(); 3431 3432 // Fully start NMT 3433 MemTracker::start(); 3434 3435 // Create the VMThread 3436 { TraceTime timer("Start VMThread", TraceStartupTime); 3437 VMThread::create(); 3438 Thread* vmthread = VMThread::vm_thread(); 3439 3440 if (!os::create_thread(vmthread, os::vm_thread)) 3441 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3442 3443 // Wait for the VM thread to become ready, and VMThread::run to initialize 3444 // Monitors can have spurious returns, must always check another state flag 3445 { 3446 MutexLocker ml(Notify_lock); 3447 os::start_thread(vmthread); 3448 while (vmthread->active_handles() == NULL) { 3449 Notify_lock->wait(); 3450 } 3451 } 3452 } 3453 3454 assert (Universe::is_fully_initialized(), "not initialized"); 3455 if (VerifyDuringStartup) { 3456 // Make sure we're starting with a clean slate. 3457 VM_Verify verify_op; 3458 VMThread::execute(&verify_op); 3459 } 3460 3461 EXCEPTION_MARK; 3462 3463 // At this point, the Universe is initialized, but we have not executed 3464 // any byte code. Now is a good time (the only time) to dump out the 3465 // internal state of the JVM for sharing. 3466 if (DumpSharedSpaces) { 3467 MetaspaceShared::preload_and_dump(CHECK_0); 3468 ShouldNotReachHere(); 3469 } 3470 3471 // Always call even when there are not JVMTI environments yet, since environments 3472 // may be attached late and JVMTI must track phases of VM execution 3473 JvmtiExport::enter_start_phase(); 3474 3475 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3476 JvmtiExport::post_vm_start(); 3477 3478 { 3479 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3480 3481 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3482 create_vm_init_libraries(); 3483 } 3484 3485 initialize_class(vmSymbols::java_lang_String(), CHECK_0); 3486 3487 if (AggressiveOpts) { 3488 { 3489 // Forcibly initialize java/util/HashMap and mutate the private 3490 // static final "frontCacheEnabled" field before we start creating instances 3491#ifdef ASSERT 3492 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3493 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 3494#endif 3495 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3496 KlassHandle k = KlassHandle(THREAD, k_o); 3497 guarantee(k.not_null(), "Must find java/util/HashMap"); 3498 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3499 ik->initialize(CHECK_0); 3500 fieldDescriptor fd; 3501 // Possible we might not find this field; if so, don't break 3502 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3503 k()->java_mirror()->bool_field_put(fd.offset(), true); 3504 } 3505 } 3506 3507 if (UseStringCache) { 3508 // Forcibly initialize java/lang/StringValue and mutate the private 3509 // static final "stringCacheEnabled" field before we start creating instances 3510 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0); 3511 // Possible that StringValue isn't present: if so, silently don't break 3512 if (k_o != NULL) { 3513 KlassHandle k = KlassHandle(THREAD, k_o); 3514 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3515 ik->initialize(CHECK_0); 3516 fieldDescriptor fd; 3517 // Possible we might not find this field: if so, silently don't break 3518 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3519 k()->java_mirror()->bool_field_put(fd.offset(), true); 3520 } 3521 } 3522 } 3523 } 3524 3525 // Initialize java_lang.System (needed before creating the thread) 3526 initialize_class(vmSymbols::java_lang_System(), CHECK_0); 3527 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0); 3528 Handle thread_group = create_initial_thread_group(CHECK_0); 3529 Universe::set_main_thread_group(thread_group()); 3530 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0); 3531 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 3532 main_thread->set_threadObj(thread_object); 3533 // Set thread status to running since main thread has 3534 // been started and running. 3535 java_lang_Thread::set_thread_status(thread_object, 3536 java_lang_Thread::RUNNABLE); 3537 3538 // The VM creates & returns objects of this class. Make sure it's initialized. 3539 initialize_class(vmSymbols::java_lang_Class(), CHECK_0); 3540 3541 // The VM preresolves methods to these classes. Make sure that they get initialized 3542 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0); 3543 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0); 3544 call_initializeSystemClass(CHECK_0); 3545 3546 // get the Java runtime name after java.lang.System is initialized 3547 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3548 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3549 3550 // an instance of OutOfMemory exception has been allocated earlier 3551 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0); 3552 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0); 3553 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0); 3554 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0); 3555 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0); 3556 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0); 3557 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0); 3558 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0); 3559 } 3560 3561 // See : bugid 4211085. 3562 // Background : the static initializer of java.lang.Compiler tries to read 3563 // property"java.compiler" and read & write property "java.vm.info". 3564 // When a security manager is installed through the command line 3565 // option "-Djava.security.manager", the above properties are not 3566 // readable and the static initializer for java.lang.Compiler fails 3567 // resulting in a NoClassDefFoundError. This can happen in any 3568 // user code which calls methods in java.lang.Compiler. 3569 // Hack : the hack is to pre-load and initialize this class, so that only 3570 // system domains are on the stack when the properties are read. 3571 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3572 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3573 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3574 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3575 // Once that is done, we should remove this hack. 3576 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0); 3577 3578 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3579 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3580 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3581 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3582 // This should also be taken out as soon as 4211383 gets fixed. 3583 reset_vm_info_property(CHECK_0); 3584 3585 quicken_jni_functions(); 3586 3587 // Must be run after init_ft which initializes ft_enabled 3588 if (TRACE_INITIALIZE() != JNI_OK) { 3589 vm_exit_during_initialization("Failed to initialize tracing backend"); 3590 } 3591 3592 // Set flag that basic initialization has completed. Used by exceptions and various 3593 // debug stuff, that does not work until all basic classes have been initialized. 3594 set_init_completed(); 3595 3596#ifndef USDT2 3597 HS_DTRACE_PROBE(hotspot, vm__init__end); 3598#else /* USDT2 */ 3599 HOTSPOT_VM_INIT_END(); 3600#endif /* USDT2 */ 3601 3602 // record VM initialization completion time 3603#if INCLUDE_MANAGEMENT 3604 Management::record_vm_init_completed(); 3605#endif // INCLUDE_MANAGEMENT 3606 3607 // Compute system loader. Note that this has to occur after set_init_completed, since 3608 // valid exceptions may be thrown in the process. 3609 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3610 // set_init_completed has just been called, causing exceptions not to be shortcut 3611 // anymore. We call vm_exit_during_initialization directly instead. 3612 SystemDictionary::compute_java_system_loader(THREAD); 3613 if (HAS_PENDING_EXCEPTION) { 3614 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3615 } 3616 3617#if INCLUDE_ALL_GCS 3618 // Support for ConcurrentMarkSweep. This should be cleaned up 3619 // and better encapsulated. The ugly nested if test would go away 3620 // once things are properly refactored. XXX YSR 3621 if (UseConcMarkSweepGC || UseG1GC) { 3622 if (UseConcMarkSweepGC) { 3623 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3624 } else { 3625 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3626 } 3627 if (HAS_PENDING_EXCEPTION) { 3628 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3629 } 3630 } 3631#endif // INCLUDE_ALL_GCS 3632 3633 // Always call even when there are not JVMTI environments yet, since environments 3634 // may be attached late and JVMTI must track phases of VM execution 3635 JvmtiExport::enter_live_phase(); 3636 3637 // Signal Dispatcher needs to be started before VMInit event is posted 3638 os::signal_init(); 3639 3640 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3641 if (!DisableAttachMechanism) { 3642 if (StartAttachListener || AttachListener::init_at_startup()) { 3643 AttachListener::init(); 3644 } 3645 } 3646 3647 // Launch -Xrun agents 3648 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3649 // back-end can launch with -Xdebug -Xrunjdwp. 3650 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3651 create_vm_init_libraries(); 3652 } 3653 3654 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3655 JvmtiExport::post_vm_initialized(); 3656 3657 if (TRACE_START() != JNI_OK) { 3658 vm_exit_during_initialization("Failed to start tracing backend."); 3659 } 3660 3661 if (CleanChunkPoolAsync) { 3662 Chunk::start_chunk_pool_cleaner_task(); 3663 } 3664 3665 // initialize compiler(s) 3666#if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3667 CompileBroker::compilation_init(); 3668#endif 3669 3670#if INCLUDE_MANAGEMENT 3671 Management::initialize(THREAD); 3672#endif // INCLUDE_MANAGEMENT 3673 3674 if (HAS_PENDING_EXCEPTION) { 3675 // management agent fails to start possibly due to 3676 // configuration problem and is responsible for printing 3677 // stack trace if appropriate. Simply exit VM. 3678 vm_exit(1); 3679 } 3680 3681 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3682 if (MemProfiling) MemProfiler::engage(); 3683 StatSampler::engage(); 3684 if (CheckJNICalls) JniPeriodicChecker::engage(); 3685 3686 BiasedLocking::init(); 3687 3688 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3689 call_postVMInitHook(THREAD); 3690 // The Java side of PostVMInitHook.run must deal with all 3691 // exceptions and provide means of diagnosis. 3692 if (HAS_PENDING_EXCEPTION) { 3693 CLEAR_PENDING_EXCEPTION; 3694 } 3695 } 3696 3697 { 3698 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3699 // Make sure the watcher thread can be started by WatcherThread::start() 3700 // or by dynamic enrollment. 3701 WatcherThread::make_startable(); 3702 // Start up the WatcherThread if there are any periodic tasks 3703 // NOTE: All PeriodicTasks should be registered by now. If they 3704 // aren't, late joiners might appear to start slowly (we might 3705 // take a while to process their first tick). 3706 if (PeriodicTask::num_tasks() > 0) { 3707 WatcherThread::start(); 3708 } 3709 } 3710 3711 // Give os specific code one last chance to start 3712 os::init_3(); 3713 3714 create_vm_timer.end(); 3715#ifdef ASSERT 3716 _vm_complete = true; 3717#endif 3718 return JNI_OK; 3719} 3720 3721// type for the Agent_OnLoad and JVM_OnLoad entry points 3722extern "C" { 3723 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3724} 3725// Find a command line agent library and return its entry point for 3726// -agentlib: -agentpath: -Xrun 3727// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3728static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3729 OnLoadEntry_t on_load_entry = NULL; 3730 void *library = agent->os_lib(); // check if we have looked it up before 3731 3732 if (library == NULL) { 3733 char buffer[JVM_MAXPATHLEN]; 3734 char ebuf[1024]; 3735 const char *name = agent->name(); 3736 const char *msg = "Could not find agent library "; 3737 3738 if (agent->is_absolute_path()) { 3739 library = os::dll_load(name, ebuf, sizeof ebuf); 3740 if (library == NULL) { 3741 const char *sub_msg = " in absolute path, with error: "; 3742 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3743 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3744 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3745 // If we can't find the agent, exit. 3746 vm_exit_during_initialization(buf, NULL); 3747 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3748 } 3749 } else { 3750 // Try to load the agent from the standard dll directory 3751 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3752 name)) { 3753 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3754 } 3755 if (library == NULL) { // Try the local directory 3756 char ns[1] = {0}; 3757 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3758 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3759 } 3760 if (library == NULL) { 3761 const char *sub_msg = " on the library path, with error: "; 3762 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3763 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3764 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3765 // If we can't find the agent, exit. 3766 vm_exit_during_initialization(buf, NULL); 3767 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3768 } 3769 } 3770 } 3771 agent->set_os_lib(library); 3772 } 3773 3774 // Find the OnLoad function. 3775 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3776 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index])); 3777 if (on_load_entry != NULL) break; 3778 } 3779 return on_load_entry; 3780} 3781 3782// Find the JVM_OnLoad entry point 3783static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3784 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3785 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3786} 3787 3788// Find the Agent_OnLoad entry point 3789static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3790 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3791 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3792} 3793 3794// For backwards compatibility with -Xrun 3795// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3796// treated like -agentpath: 3797// Must be called before agent libraries are created 3798void Threads::convert_vm_init_libraries_to_agents() { 3799 AgentLibrary* agent; 3800 AgentLibrary* next; 3801 3802 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3803 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3804 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3805 3806 // If there is an JVM_OnLoad function it will get called later, 3807 // otherwise see if there is an Agent_OnLoad 3808 if (on_load_entry == NULL) { 3809 on_load_entry = lookup_agent_on_load(agent); 3810 if (on_load_entry != NULL) { 3811 // switch it to the agent list -- so that Agent_OnLoad will be called, 3812 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3813 Arguments::convert_library_to_agent(agent); 3814 } else { 3815 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3816 } 3817 } 3818 } 3819} 3820 3821// Create agents for -agentlib: -agentpath: and converted -Xrun 3822// Invokes Agent_OnLoad 3823// Called very early -- before JavaThreads exist 3824void Threads::create_vm_init_agents() { 3825 extern struct JavaVM_ main_vm; 3826 AgentLibrary* agent; 3827 3828 JvmtiExport::enter_onload_phase(); 3829 3830 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3831 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3832 3833 if (on_load_entry != NULL) { 3834 // Invoke the Agent_OnLoad function 3835 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3836 if (err != JNI_OK) { 3837 vm_exit_during_initialization("agent library failed to init", agent->name()); 3838 } 3839 } else { 3840 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3841 } 3842 } 3843 JvmtiExport::enter_primordial_phase(); 3844} 3845 3846extern "C" { 3847 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3848} 3849 3850void Threads::shutdown_vm_agents() { 3851 // Send any Agent_OnUnload notifications 3852 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3853 extern struct JavaVM_ main_vm; 3854 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3855 3856 // Find the Agent_OnUnload function. 3857 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3858 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3859 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3860 3861 // Invoke the Agent_OnUnload function 3862 if (unload_entry != NULL) { 3863 JavaThread* thread = JavaThread::current(); 3864 ThreadToNativeFromVM ttn(thread); 3865 HandleMark hm(thread); 3866 (*unload_entry)(&main_vm); 3867 break; 3868 } 3869 } 3870 } 3871} 3872 3873// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3874// Invokes JVM_OnLoad 3875void Threads::create_vm_init_libraries() { 3876 extern struct JavaVM_ main_vm; 3877 AgentLibrary* agent; 3878 3879 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3880 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3881 3882 if (on_load_entry != NULL) { 3883 // Invoke the JVM_OnLoad function 3884 JavaThread* thread = JavaThread::current(); 3885 ThreadToNativeFromVM ttn(thread); 3886 HandleMark hm(thread); 3887 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3888 if (err != JNI_OK) { 3889 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3890 } 3891 } else { 3892 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3893 } 3894 } 3895} 3896 3897// Last thread running calls java.lang.Shutdown.shutdown() 3898void JavaThread::invoke_shutdown_hooks() { 3899 HandleMark hm(this); 3900 3901 // We could get here with a pending exception, if so clear it now. 3902 if (this->has_pending_exception()) { 3903 this->clear_pending_exception(); 3904 } 3905 3906 EXCEPTION_MARK; 3907 Klass* k = 3908 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3909 THREAD); 3910 if (k != NULL) { 3911 // SystemDictionary::resolve_or_null will return null if there was 3912 // an exception. If we cannot load the Shutdown class, just don't 3913 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3914 // and finalizers (if runFinalizersOnExit is set) won't be run. 3915 // Note that if a shutdown hook was registered or runFinalizersOnExit 3916 // was called, the Shutdown class would have already been loaded 3917 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3918 instanceKlassHandle shutdown_klass (THREAD, k); 3919 JavaValue result(T_VOID); 3920 JavaCalls::call_static(&result, 3921 shutdown_klass, 3922 vmSymbols::shutdown_method_name(), 3923 vmSymbols::void_method_signature(), 3924 THREAD); 3925 } 3926 CLEAR_PENDING_EXCEPTION; 3927} 3928 3929// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3930// the program falls off the end of main(). Another VM exit path is through 3931// vm_exit() when the program calls System.exit() to return a value or when 3932// there is a serious error in VM. The two shutdown paths are not exactly 3933// the same, but they share Shutdown.shutdown() at Java level and before_exit() 3934// and VM_Exit op at VM level. 3935// 3936// Shutdown sequence: 3937// + Shutdown native memory tracking if it is on 3938// + Wait until we are the last non-daemon thread to execute 3939// <-- every thing is still working at this moment --> 3940// + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3941// shutdown hooks, run finalizers if finalization-on-exit 3942// + Call before_exit(), prepare for VM exit 3943// > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3944// currently the only user of this mechanism is File.deleteOnExit()) 3945// > stop flat profiler, StatSampler, watcher thread, CMS threads, 3946// post thread end and vm death events to JVMTI, 3947// stop signal thread 3948// + Call JavaThread::exit(), it will: 3949// > release JNI handle blocks, remove stack guard pages 3950// > remove this thread from Threads list 3951// <-- no more Java code from this thread after this point --> 3952// + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3953// the compiler threads at safepoint 3954// <-- do not use anything that could get blocked by Safepoint --> 3955// + Disable tracing at JNI/JVM barriers 3956// + Set _vm_exited flag for threads that are still running native code 3957// + Delete this thread 3958// + Call exit_globals() 3959// > deletes tty 3960// > deletes PerfMemory resources 3961// + Return to caller 3962 3963bool Threads::destroy_vm() { 3964 JavaThread* thread = JavaThread::current(); 3965 3966#ifdef ASSERT 3967 _vm_complete = false; 3968#endif 3969 // Wait until we are the last non-daemon thread to execute 3970 { MutexLocker nu(Threads_lock); 3971 while (Threads::number_of_non_daemon_threads() > 1 ) 3972 // This wait should make safepoint checks, wait without a timeout, 3973 // and wait as a suspend-equivalent condition. 3974 // 3975 // Note: If the FlatProfiler is running and this thread is waiting 3976 // for another non-daemon thread to finish, then the FlatProfiler 3977 // is waiting for the external suspend request on this thread to 3978 // complete. wait_for_ext_suspend_completion() will eventually 3979 // timeout, but that takes time. Making this wait a suspend- 3980 // equivalent condition solves that timeout problem. 3981 // 3982 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 3983 Mutex::_as_suspend_equivalent_flag); 3984 } 3985 3986 // Hang forever on exit if we are reporting an error. 3987 if (ShowMessageBoxOnError && is_error_reported()) { 3988 os::infinite_sleep(); 3989 } 3990 os::wait_for_keypress_at_exit(); 3991 3992 if (JDK_Version::is_jdk12x_version()) { 3993 // We are the last thread running, so check if finalizers should be run. 3994 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 3995 HandleMark rm(thread); 3996 Universe::run_finalizers_on_exit(); 3997 } else { 3998 // run Java level shutdown hooks 3999 thread->invoke_shutdown_hooks(); 4000 } 4001 4002 before_exit(thread); 4003 4004 thread->exit(true); 4005 4006 // Stop VM thread. 4007 { 4008 // 4945125 The vm thread comes to a safepoint during exit. 4009 // GC vm_operations can get caught at the safepoint, and the 4010 // heap is unparseable if they are caught. Grab the Heap_lock 4011 // to prevent this. The GC vm_operations will not be able to 4012 // queue until after the vm thread is dead. 4013 // After this point, we'll never emerge out of the safepoint before 4014 // the VM exits, so concurrent GC threads do not need to be explicitly 4015 // stopped; they remain inactive until the process exits. 4016 // Note: some concurrent G1 threads may be running during a safepoint, 4017 // but these will not be accessing the heap, just some G1-specific side 4018 // data structures that are not accessed by any other threads but them 4019 // after this point in a terminal safepoint. 4020 4021 MutexLocker ml(Heap_lock); 4022 4023 VMThread::wait_for_vm_thread_exit(); 4024 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4025 VMThread::destroy(); 4026 } 4027 4028 // clean up ideal graph printers 4029#if defined(COMPILER2) && !defined(PRODUCT) 4030 IdealGraphPrinter::clean_up(); 4031#endif 4032 4033 // Now, all Java threads are gone except daemon threads. Daemon threads 4034 // running Java code or in VM are stopped by the Safepoint. However, 4035 // daemon threads executing native code are still running. But they 4036 // will be stopped at native=>Java/VM barriers. Note that we can't 4037 // simply kill or suspend them, as it is inherently deadlock-prone. 4038 4039#ifndef PRODUCT 4040 // disable function tracing at JNI/JVM barriers 4041 TraceJNICalls = false; 4042 TraceJVMCalls = false; 4043 TraceRuntimeCalls = false; 4044#endif 4045 4046 VM_Exit::set_vm_exited(); 4047 4048 notify_vm_shutdown(); 4049 4050 delete thread; 4051 4052 // exit_globals() will delete tty 4053 exit_globals(); 4054 4055 return true; 4056} 4057 4058 4059jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4060 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4061 return is_supported_jni_version(version); 4062} 4063 4064 4065jboolean Threads::is_supported_jni_version(jint version) { 4066 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4067 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4068 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4069 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4070 return JNI_FALSE; 4071} 4072 4073 4074void Threads::add(JavaThread* p, bool force_daemon) { 4075 // The threads lock must be owned at this point 4076 assert_locked_or_safepoint(Threads_lock); 4077 4078 // See the comment for this method in thread.hpp for its purpose and 4079 // why it is called here. 4080 p->initialize_queues(); 4081 p->set_next(_thread_list); 4082 _thread_list = p; 4083 _number_of_threads++; 4084 oop threadObj = p->threadObj(); 4085 bool daemon = true; 4086 // Bootstrapping problem: threadObj can be null for initial 4087 // JavaThread (or for threads attached via JNI) 4088 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4089 _number_of_non_daemon_threads++; 4090 daemon = false; 4091 } 4092 4093 p->set_safepoint_visible(true); 4094 4095 ThreadService::add_thread(p, daemon); 4096 4097 // Possible GC point. 4098 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4099} 4100 4101void Threads::remove(JavaThread* p) { 4102 // Extra scope needed for Thread_lock, so we can check 4103 // that we do not remove thread without safepoint code notice 4104 { MutexLocker ml(Threads_lock); 4105 4106 assert(includes(p), "p must be present"); 4107 4108 JavaThread* current = _thread_list; 4109 JavaThread* prev = NULL; 4110 4111 while (current != p) { 4112 prev = current; 4113 current = current->next(); 4114 } 4115 4116 if (prev) { 4117 prev->set_next(current->next()); 4118 } else { 4119 _thread_list = p->next(); 4120 } 4121 _number_of_threads--; 4122 oop threadObj = p->threadObj(); 4123 bool daemon = true; 4124 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4125 _number_of_non_daemon_threads--; 4126 daemon = false; 4127 4128 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4129 // on destroy_vm will wake up. 4130 if (number_of_non_daemon_threads() == 1) 4131 Threads_lock->notify_all(); 4132 } 4133 ThreadService::remove_thread(p, daemon); 4134 4135 // Make sure that safepoint code disregard this thread. This is needed since 4136 // the thread might mess around with locks after this point. This can cause it 4137 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4138 // of this thread since it is removed from the queue. 4139 p->set_terminated_value(); 4140 4141 // Now, this thread is not visible to safepoint 4142 p->set_safepoint_visible(false); 4143 // once the thread becomes safepoint invisible, we can not use its per-thread 4144 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4145 // to release its per-thread recorder here. 4146 MemTracker::thread_exiting(p); 4147 } // unlock Threads_lock 4148 4149 // Since Events::log uses a lock, we grab it outside the Threads_lock 4150 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4151} 4152 4153// Threads_lock must be held when this is called (or must be called during a safepoint) 4154bool Threads::includes(JavaThread* p) { 4155 assert(Threads_lock->is_locked(), "sanity check"); 4156 ALL_JAVA_THREADS(q) { 4157 if (q == p ) { 4158 return true; 4159 } 4160 } 4161 return false; 4162} 4163 4164// Operations on the Threads list for GC. These are not explicitly locked, 4165// but the garbage collector must provide a safe context for them to run. 4166// In particular, these things should never be called when the Threads_lock 4167// is held by some other thread. (Note: the Safepoint abstraction also 4168// uses the Threads_lock to gurantee this property. It also makes sure that 4169// all threads gets blocked when exiting or starting). 4170 4171void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4172 ALL_JAVA_THREADS(p) { 4173 p->oops_do(f, cld_f, cf); 4174 } 4175 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4176} 4177 4178void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4179 // Introduce a mechanism allowing parallel threads to claim threads as 4180 // root groups. Overhead should be small enough to use all the time, 4181 // even in sequential code. 4182 SharedHeap* sh = SharedHeap::heap(); 4183 // Cannot yet substitute active_workers for n_par_threads 4184 // because of G1CollectedHeap::verify() use of 4185 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4186 // turn off parallelism in process_strong_roots while active_workers 4187 // is being used for parallelism elsewhere. 4188 bool is_par = sh->n_par_threads() > 0; 4189 assert(!is_par || 4190 (SharedHeap::heap()->n_par_threads() == 4191 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4192 int cp = SharedHeap::heap()->strong_roots_parity(); 4193 ALL_JAVA_THREADS(p) { 4194 if (p->claim_oops_do(is_par, cp)) { 4195 p->oops_do(f, cld_f, cf); 4196 } 4197 } 4198 VMThread* vmt = VMThread::vm_thread(); 4199 if (vmt->claim_oops_do(is_par, cp)) { 4200 vmt->oops_do(f, cld_f, cf); 4201 } 4202} 4203 4204#if INCLUDE_ALL_GCS 4205// Used by ParallelScavenge 4206void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4207 ALL_JAVA_THREADS(p) { 4208 q->enqueue(new ThreadRootsTask(p)); 4209 } 4210 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4211} 4212 4213// Used by Parallel Old 4214void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4215 ALL_JAVA_THREADS(p) { 4216 q->enqueue(new ThreadRootsMarkingTask(p)); 4217 } 4218 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4219} 4220#endif // INCLUDE_ALL_GCS 4221 4222void Threads::nmethods_do(CodeBlobClosure* cf) { 4223 ALL_JAVA_THREADS(p) { 4224 p->nmethods_do(cf); 4225 } 4226 VMThread::vm_thread()->nmethods_do(cf); 4227} 4228 4229void Threads::metadata_do(void f(Metadata*)) { 4230 ALL_JAVA_THREADS(p) { 4231 p->metadata_do(f); 4232 } 4233} 4234 4235void Threads::gc_epilogue() { 4236 ALL_JAVA_THREADS(p) { 4237 p->gc_epilogue(); 4238 } 4239} 4240 4241void Threads::gc_prologue() { 4242 ALL_JAVA_THREADS(p) { 4243 p->gc_prologue(); 4244 } 4245} 4246 4247void Threads::deoptimized_wrt_marked_nmethods() { 4248 ALL_JAVA_THREADS(p) { 4249 p->deoptimized_wrt_marked_nmethods(); 4250 } 4251} 4252 4253 4254// Get count Java threads that are waiting to enter the specified monitor. 4255GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4256 address monitor, bool doLock) { 4257 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4258 "must grab Threads_lock or be at safepoint"); 4259 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4260 4261 int i = 0; 4262 { 4263 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4264 ALL_JAVA_THREADS(p) { 4265 if (p->is_Compiler_thread()) continue; 4266 4267 address pending = (address)p->current_pending_monitor(); 4268 if (pending == monitor) { // found a match 4269 if (i < count) result->append(p); // save the first count matches 4270 i++; 4271 } 4272 } 4273 } 4274 return result; 4275} 4276 4277 4278JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4279 assert(doLock || 4280 Threads_lock->owned_by_self() || 4281 SafepointSynchronize::is_at_safepoint(), 4282 "must grab Threads_lock or be at safepoint"); 4283 4284 // NULL owner means not locked so we can skip the search 4285 if (owner == NULL) return NULL; 4286 4287 { 4288 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4289 ALL_JAVA_THREADS(p) { 4290 // first, see if owner is the address of a Java thread 4291 if (owner == (address)p) return p; 4292 } 4293 } 4294 // Cannot assert on lack of success here since this function may be 4295 // used by code that is trying to report useful problem information 4296 // like deadlock detection. 4297 if (UseHeavyMonitors) return NULL; 4298 4299 // 4300 // If we didn't find a matching Java thread and we didn't force use of 4301 // heavyweight monitors, then the owner is the stack address of the 4302 // Lock Word in the owning Java thread's stack. 4303 // 4304 JavaThread* the_owner = NULL; 4305 { 4306 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4307 ALL_JAVA_THREADS(q) { 4308 if (q->is_lock_owned(owner)) { 4309 the_owner = q; 4310 break; 4311 } 4312 } 4313 } 4314 // cannot assert on lack of success here; see above comment 4315 return the_owner; 4316} 4317 4318// Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4319void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4320 char buf[32]; 4321 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4322 4323 st->print_cr("Full thread dump %s (%s %s):", 4324 Abstract_VM_Version::vm_name(), 4325 Abstract_VM_Version::vm_release(), 4326 Abstract_VM_Version::vm_info_string() 4327 ); 4328 st->cr(); 4329 4330#if INCLUDE_ALL_GCS 4331 // Dump concurrent locks 4332 ConcurrentLocksDump concurrent_locks; 4333 if (print_concurrent_locks) { 4334 concurrent_locks.dump_at_safepoint(); 4335 } 4336#endif // INCLUDE_ALL_GCS 4337 4338 ALL_JAVA_THREADS(p) { 4339 ResourceMark rm; 4340 p->print_on(st); 4341 if (print_stacks) { 4342 if (internal_format) { 4343 p->trace_stack(); 4344 } else { 4345 p->print_stack_on(st); 4346 } 4347 } 4348 st->cr(); 4349#if INCLUDE_ALL_GCS 4350 if (print_concurrent_locks) { 4351 concurrent_locks.print_locks_on(p, st); 4352 } 4353#endif // INCLUDE_ALL_GCS 4354 } 4355 4356 VMThread::vm_thread()->print_on(st); 4357 st->cr(); 4358 Universe::heap()->print_gc_threads_on(st); 4359 WatcherThread* wt = WatcherThread::watcher_thread(); 4360 if (wt != NULL) { 4361 wt->print_on(st); 4362 st->cr(); 4363 } 4364 CompileBroker::print_compiler_threads_on(st); 4365 st->flush(); 4366} 4367 4368// Threads::print_on_error() is called by fatal error handler. It's possible 4369// that VM is not at safepoint and/or current thread is inside signal handler. 4370// Don't print stack trace, as the stack may not be walkable. Don't allocate 4371// memory (even in resource area), it might deadlock the error handler. 4372void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4373 bool found_current = false; 4374 st->print_cr("Java Threads: ( => current thread )"); 4375 ALL_JAVA_THREADS(thread) { 4376 bool is_current = (current == thread); 4377 found_current = found_current || is_current; 4378 4379 st->print("%s", is_current ? "=>" : " "); 4380 4381 st->print(PTR_FORMAT, thread); 4382 st->print(" "); 4383 thread->print_on_error(st, buf, buflen); 4384 st->cr(); 4385 } 4386 st->cr(); 4387 4388 st->print_cr("Other Threads:"); 4389 if (VMThread::vm_thread()) { 4390 bool is_current = (current == VMThread::vm_thread()); 4391 found_current = found_current || is_current; 4392 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4393 4394 st->print(PTR_FORMAT, VMThread::vm_thread()); 4395 st->print(" "); 4396 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4397 st->cr(); 4398 } 4399 WatcherThread* wt = WatcherThread::watcher_thread(); 4400 if (wt != NULL) { 4401 bool is_current = (current == wt); 4402 found_current = found_current || is_current; 4403 st->print("%s", is_current ? "=>" : " "); 4404 4405 st->print(PTR_FORMAT, wt); 4406 st->print(" "); 4407 wt->print_on_error(st, buf, buflen); 4408 st->cr(); 4409 } 4410 if (!found_current) { 4411 st->cr(); 4412 st->print("=>" PTR_FORMAT " (exited) ", current); 4413 current->print_on_error(st, buf, buflen); 4414 st->cr(); 4415 } 4416} 4417 4418// Internal SpinLock and Mutex 4419// Based on ParkEvent 4420 4421// Ad-hoc mutual exclusion primitives: SpinLock and Mux 4422// 4423// We employ SpinLocks _only for low-contention, fixed-length 4424// short-duration critical sections where we're concerned 4425// about native mutex_t or HotSpot Mutex:: latency. 4426// The mux construct provides a spin-then-block mutual exclusion 4427// mechanism. 4428// 4429// Testing has shown that contention on the ListLock guarding gFreeList 4430// is common. If we implement ListLock as a simple SpinLock it's common 4431// for the JVM to devolve to yielding with little progress. This is true 4432// despite the fact that the critical sections protected by ListLock are 4433// extremely short. 4434// 4435// TODO-FIXME: ListLock should be of type SpinLock. 4436// We should make this a 1st-class type, integrated into the lock 4437// hierarchy as leaf-locks. Critically, the SpinLock structure 4438// should have sufficient padding to avoid false-sharing and excessive 4439// cache-coherency traffic. 4440 4441 4442typedef volatile int SpinLockT ; 4443 4444void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4445 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4446 return ; // normal fast-path return 4447 } 4448 4449 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4450 TEVENT (SpinAcquire - ctx) ; 4451 int ctr = 0 ; 4452 int Yields = 0 ; 4453 for (;;) { 4454 while (*adr != 0) { 4455 ++ctr ; 4456 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4457 if (Yields > 5) { 4458 // Consider using a simple NakedSleep() instead. 4459 // Then SpinAcquire could be called by non-JVM threads 4460 Thread::current()->_ParkEvent->park(1) ; 4461 } else { 4462 os::NakedYield() ; 4463 ++Yields ; 4464 } 4465 } else { 4466 SpinPause() ; 4467 } 4468 } 4469 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4470 } 4471} 4472 4473void Thread::SpinRelease (volatile int * adr) { 4474 assert (*adr != 0, "invariant") ; 4475 OrderAccess::fence() ; // guarantee at least release consistency. 4476 // Roach-motel semantics. 4477 // It's safe if subsequent LDs and STs float "up" into the critical section, 4478 // but prior LDs and STs within the critical section can't be allowed 4479 // to reorder or float past the ST that releases the lock. 4480 *adr = 0 ; 4481} 4482 4483// muxAcquire and muxRelease: 4484// 4485// * muxAcquire and muxRelease support a single-word lock-word construct. 4486// The LSB of the word is set IFF the lock is held. 4487// The remainder of the word points to the head of a singly-linked list 4488// of threads blocked on the lock. 4489// 4490// * The current implementation of muxAcquire-muxRelease uses its own 4491// dedicated Thread._MuxEvent instance. If we're interested in 4492// minimizing the peak number of extant ParkEvent instances then 4493// we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4494// as certain invariants were satisfied. Specifically, care would need 4495// to be taken with regards to consuming unpark() "permits". 4496// A safe rule of thumb is that a thread would never call muxAcquire() 4497// if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4498// park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4499// consume an unpark() permit intended for monitorenter, for instance. 4500// One way around this would be to widen the restricted-range semaphore 4501// implemented in park(). Another alternative would be to provide 4502// multiple instances of the PlatformEvent() for each thread. One 4503// instance would be dedicated to muxAcquire-muxRelease, for instance. 4504// 4505// * Usage: 4506// -- Only as leaf locks 4507// -- for short-term locking only as muxAcquire does not perform 4508// thread state transitions. 4509// 4510// Alternatives: 4511// * We could implement muxAcquire and muxRelease with MCS or CLH locks 4512// but with parking or spin-then-park instead of pure spinning. 4513// * Use Taura-Oyama-Yonenzawa locks. 4514// * It's possible to construct a 1-0 lock if we encode the lockword as 4515// (List,LockByte). Acquire will CAS the full lockword while Release 4516// will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4517// acquiring threads use timers (ParkTimed) to detect and recover from 4518// the stranding window. Thread/Node structures must be aligned on 256-byte 4519// boundaries by using placement-new. 4520// * Augment MCS with advisory back-link fields maintained with CAS(). 4521// Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4522// The validity of the backlinks must be ratified before we trust the value. 4523// If the backlinks are invalid the exiting thread must back-track through the 4524// the forward links, which are always trustworthy. 4525// * Add a successor indication. The LockWord is currently encoded as 4526// (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4527// to provide the usual futile-wakeup optimization. 4528// See RTStt for details. 4529// * Consider schedctl.sc_nopreempt to cover the critical section. 4530// 4531 4532 4533typedef volatile intptr_t MutexT ; // Mux Lock-word 4534enum MuxBits { LOCKBIT = 1 } ; 4535 4536void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4537 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4538 if (w == 0) return ; 4539 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4540 return ; 4541 } 4542 4543 TEVENT (muxAcquire - Contention) ; 4544 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4545 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4546 for (;;) { 4547 int its = (os::is_MP() ? 100 : 0) + 1 ; 4548 4549 // Optional spin phase: spin-then-park strategy 4550 while (--its >= 0) { 4551 w = *Lock ; 4552 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4553 return ; 4554 } 4555 } 4556 4557 Self->reset() ; 4558 Self->OnList = intptr_t(Lock) ; 4559 // The following fence() isn't _strictly necessary as the subsequent 4560 // CAS() both serializes execution and ratifies the fetched *Lock value. 4561 OrderAccess::fence(); 4562 for (;;) { 4563 w = *Lock ; 4564 if ((w & LOCKBIT) == 0) { 4565 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4566 Self->OnList = 0 ; // hygiene - allows stronger asserts 4567 return ; 4568 } 4569 continue ; // Interference -- *Lock changed -- Just retry 4570 } 4571 assert (w & LOCKBIT, "invariant") ; 4572 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4573 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4574 } 4575 4576 while (Self->OnList != 0) { 4577 Self->park() ; 4578 } 4579 } 4580} 4581 4582void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4583 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4584 if (w == 0) return ; 4585 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4586 return ; 4587 } 4588 4589 TEVENT (muxAcquire - Contention) ; 4590 ParkEvent * ReleaseAfter = NULL ; 4591 if (ev == NULL) { 4592 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4593 } 4594 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4595 for (;;) { 4596 guarantee (ev->OnList == 0, "invariant") ; 4597 int its = (os::is_MP() ? 100 : 0) + 1 ; 4598 4599 // Optional spin phase: spin-then-park strategy 4600 while (--its >= 0) { 4601 w = *Lock ; 4602 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4603 if (ReleaseAfter != NULL) { 4604 ParkEvent::Release (ReleaseAfter) ; 4605 } 4606 return ; 4607 } 4608 } 4609 4610 ev->reset() ; 4611 ev->OnList = intptr_t(Lock) ; 4612 // The following fence() isn't _strictly necessary as the subsequent 4613 // CAS() both serializes execution and ratifies the fetched *Lock value. 4614 OrderAccess::fence(); 4615 for (;;) { 4616 w = *Lock ; 4617 if ((w & LOCKBIT) == 0) { 4618 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4619 ev->OnList = 0 ; 4620 // We call ::Release while holding the outer lock, thus 4621 // artificially lengthening the critical section. 4622 // Consider deferring the ::Release() until the subsequent unlock(), 4623 // after we've dropped the outer lock. 4624 if (ReleaseAfter != NULL) { 4625 ParkEvent::Release (ReleaseAfter) ; 4626 } 4627 return ; 4628 } 4629 continue ; // Interference -- *Lock changed -- Just retry 4630 } 4631 assert (w & LOCKBIT, "invariant") ; 4632 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4633 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4634 } 4635 4636 while (ev->OnList != 0) { 4637 ev->park() ; 4638 } 4639 } 4640} 4641 4642// Release() must extract a successor from the list and then wake that thread. 4643// It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4644// similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4645// Release() would : 4646// (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4647// (B) Extract a successor from the private list "in-hand" 4648// (C) attempt to CAS() the residual back into *Lock over null. 4649// If there were any newly arrived threads and the CAS() would fail. 4650// In that case Release() would detach the RATs, re-merge the list in-hand 4651// with the RATs and repeat as needed. Alternately, Release() might 4652// detach and extract a successor, but then pass the residual list to the wakee. 4653// The wakee would be responsible for reattaching and remerging before it 4654// competed for the lock. 4655// 4656// Both "pop" and DMR are immune from ABA corruption -- there can be 4657// multiple concurrent pushers, but only one popper or detacher. 4658// This implementation pops from the head of the list. This is unfair, 4659// but tends to provide excellent throughput as hot threads remain hot. 4660// (We wake recently run threads first). 4661 4662void Thread::muxRelease (volatile intptr_t * Lock) { 4663 for (;;) { 4664 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4665 assert (w & LOCKBIT, "invariant") ; 4666 if (w == LOCKBIT) return ; 4667 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4668 assert (List != NULL, "invariant") ; 4669 assert (List->OnList == intptr_t(Lock), "invariant") ; 4670 ParkEvent * nxt = List->ListNext ; 4671 4672 // The following CAS() releases the lock and pops the head element. 4673 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4674 continue ; 4675 } 4676 List->OnList = 0 ; 4677 OrderAccess::fence() ; 4678 List->unpark () ; 4679 return ; 4680 } 4681} 4682 4683 4684void Threads::verify() { 4685 ALL_JAVA_THREADS(p) { 4686 p->verify(); 4687 } 4688 VMThread* thread = VMThread::vm_thread(); 4689 if (thread != NULL) thread->verify(); 4690} 4691