thread.cpp revision 3890:d2f8c38e543d
1/* 2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "precompiled.hpp" 26#include "classfile/classLoader.hpp" 27#include "classfile/javaClasses.hpp" 28#include "classfile/systemDictionary.hpp" 29#include "classfile/vmSymbols.hpp" 30#include "code/scopeDesc.hpp" 31#include "compiler/compileBroker.hpp" 32#include "interpreter/interpreter.hpp" 33#include "interpreter/linkResolver.hpp" 34#include "interpreter/oopMapCache.hpp" 35#include "jvmtifiles/jvmtiEnv.hpp" 36#include "memory/gcLocker.inline.hpp" 37#include "memory/metaspaceShared.hpp" 38#include "memory/oopFactory.hpp" 39#include "memory/universe.inline.hpp" 40#include "oops/instanceKlass.hpp" 41#include "oops/objArrayOop.hpp" 42#include "oops/oop.inline.hpp" 43#include "oops/symbol.hpp" 44#include "prims/jvm_misc.hpp" 45#include "prims/jvmtiExport.hpp" 46#include "prims/jvmtiThreadState.hpp" 47#include "prims/privilegedStack.hpp" 48#include "runtime/aprofiler.hpp" 49#include "runtime/arguments.hpp" 50#include "runtime/biasedLocking.hpp" 51#include "runtime/deoptimization.hpp" 52#include "runtime/fprofiler.hpp" 53#include "runtime/frame.inline.hpp" 54#include "runtime/init.hpp" 55#include "runtime/interfaceSupport.hpp" 56#include "runtime/java.hpp" 57#include "runtime/javaCalls.hpp" 58#include "runtime/jniPeriodicChecker.hpp" 59#include "runtime/memprofiler.hpp" 60#include "runtime/mutexLocker.hpp" 61#include "runtime/objectMonitor.hpp" 62#include "runtime/osThread.hpp" 63#include "runtime/safepoint.hpp" 64#include "runtime/sharedRuntime.hpp" 65#include "runtime/statSampler.hpp" 66#include "runtime/stubRoutines.hpp" 67#include "runtime/task.hpp" 68#include "runtime/thread.inline.hpp" 69#include "runtime/threadCritical.hpp" 70#include "runtime/threadLocalStorage.hpp" 71#include "runtime/vframe.hpp" 72#include "runtime/vframeArray.hpp" 73#include "runtime/vframe_hp.hpp" 74#include "runtime/vmThread.hpp" 75#include "runtime/vm_operations.hpp" 76#include "services/attachListener.hpp" 77#include "services/management.hpp" 78#include "services/memTracker.hpp" 79#include "services/threadService.hpp" 80#include "trace/traceEventTypes.hpp" 81#include "utilities/defaultStream.hpp" 82#include "utilities/dtrace.hpp" 83#include "utilities/events.hpp" 84#include "utilities/preserveException.hpp" 85#ifdef TARGET_OS_FAMILY_linux 86# include "os_linux.inline.hpp" 87#endif 88#ifdef TARGET_OS_FAMILY_solaris 89# include "os_solaris.inline.hpp" 90#endif 91#ifdef TARGET_OS_FAMILY_windows 92# include "os_windows.inline.hpp" 93#endif 94#ifdef TARGET_OS_FAMILY_bsd 95# include "os_bsd.inline.hpp" 96#endif 97#ifndef SERIALGC 98#include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp" 99#include "gc_implementation/g1/concurrentMarkThread.inline.hpp" 100#include "gc_implementation/parallelScavenge/pcTasks.hpp" 101#endif 102#ifdef COMPILER1 103#include "c1/c1_Compiler.hpp" 104#endif 105#ifdef COMPILER2 106#include "opto/c2compiler.hpp" 107#include "opto/idealGraphPrinter.hpp" 108#endif 109 110#ifdef DTRACE_ENABLED 111 112// Only bother with this argument setup if dtrace is available 113 114#ifndef USDT2 115HS_DTRACE_PROBE_DECL(hotspot, vm__init__begin); 116HS_DTRACE_PROBE_DECL(hotspot, vm__init__end); 117HS_DTRACE_PROBE_DECL5(hotspot, thread__start, char*, intptr_t, 118 intptr_t, intptr_t, bool); 119HS_DTRACE_PROBE_DECL5(hotspot, thread__stop, char*, intptr_t, 120 intptr_t, intptr_t, bool); 121 122#define DTRACE_THREAD_PROBE(probe, javathread) \ 123 { \ 124 ResourceMark rm(this); \ 125 int len = 0; \ 126 const char* name = (javathread)->get_thread_name(); \ 127 len = strlen(name); \ 128 HS_DTRACE_PROBE5(hotspot, thread__##probe, \ 129 name, len, \ 130 java_lang_Thread::thread_id((javathread)->threadObj()), \ 131 (javathread)->osthread()->thread_id(), \ 132 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 133 } 134 135#else /* USDT2 */ 136 137#define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_PROBE_START 138#define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_PROBE_STOP 139 140#define DTRACE_THREAD_PROBE(probe, javathread) \ 141 { \ 142 ResourceMark rm(this); \ 143 int len = 0; \ 144 const char* name = (javathread)->get_thread_name(); \ 145 len = strlen(name); \ 146 HOTSPOT_THREAD_PROBE_##probe( /* probe = start, stop */ \ 147 (char *) name, len, \ 148 java_lang_Thread::thread_id((javathread)->threadObj()), \ 149 (uintptr_t) (javathread)->osthread()->thread_id(), \ 150 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 151 } 152 153#endif /* USDT2 */ 154 155#else // ndef DTRACE_ENABLED 156 157#define DTRACE_THREAD_PROBE(probe, javathread) 158 159#endif // ndef DTRACE_ENABLED 160 161 162// Class hierarchy 163// - Thread 164// - VMThread 165// - WatcherThread 166// - ConcurrentMarkSweepThread 167// - JavaThread 168// - CompilerThread 169 170// ======= Thread ======== 171// Support for forcing alignment of thread objects for biased locking 172void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 173 if (UseBiasedLocking) { 174 const int alignment = markOopDesc::biased_lock_alignment; 175 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 176 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 177 : AllocateHeap(aligned_size, flags, CURRENT_PC, 178 AllocFailStrategy::RETURN_NULL); 179 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 180 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 181 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 182 "JavaThread alignment code overflowed allocated storage"); 183 if (TraceBiasedLocking) { 184 if (aligned_addr != real_malloc_addr) 185 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 186 real_malloc_addr, aligned_addr); 187 } 188 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 189 return aligned_addr; 190 } else { 191 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 192 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 193 } 194} 195 196void Thread::operator delete(void* p) { 197 if (UseBiasedLocking) { 198 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 199 FreeHeap(real_malloc_addr, mtThread); 200 } else { 201 FreeHeap(p, mtThread); 202 } 203} 204 205 206// Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 207// JavaThread 208 209 210Thread::Thread() { 211 // stack and get_thread 212 set_stack_base(NULL); 213 set_stack_size(0); 214 set_self_raw_id(0); 215 set_lgrp_id(-1); 216 217 // allocated data structures 218 set_osthread(NULL); 219 set_resource_area(new (mtThread)ResourceArea()); 220 set_handle_area(new (mtThread) HandleArea(NULL)); 221 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(300, true)); 222 set_active_handles(NULL); 223 set_free_handle_block(NULL); 224 set_last_handle_mark(NULL); 225 226 // This initial value ==> never claimed. 227 _oops_do_parity = 0; 228 229 // the handle mark links itself to last_handle_mark 230 new HandleMark(this); 231 232 // plain initialization 233 debug_only(_owned_locks = NULL;) 234 debug_only(_allow_allocation_count = 0;) 235 NOT_PRODUCT(_allow_safepoint_count = 0;) 236 NOT_PRODUCT(_skip_gcalot = false;) 237 CHECK_UNHANDLED_OOPS_ONLY(_gc_locked_out_count = 0;) 238 _jvmti_env_iteration_count = 0; 239 set_allocated_bytes(0); 240 set_trace_buffer(NULL); 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 // CR 7190089: on Solaris, primordial thread's stack is adjusted 315 // in initialize_thread(). Without the adjustment, stack size is 316 // incorrect if stack is set to unlimited (ulimit -s unlimited). 317 // So far, only Solaris has real implementation of initialize_thread(). 318 // 319 // set up any platform-specific state. 320 os::initialize_thread(this); 321 322#if INCLUDE_NMT 323 // record thread's native stack, stack grows downward 324 address stack_low_addr = stack_base() - stack_size(); 325 MemTracker::record_thread_stack(stack_low_addr, stack_size(), this, 326 CURRENT_PC); 327#endif // INCLUDE_NMT 328} 329 330 331Thread::~Thread() { 332 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 333 ObjectSynchronizer::omFlush (this) ; 334 335 // stack_base can be NULL if the thread is never started or exited before 336 // record_stack_base_and_size called. Although, we would like to ensure 337 // that all started threads do call record_stack_base_and_size(), there is 338 // not proper way to enforce that. 339#if INCLUDE_NMT 340 if (_stack_base != NULL) { 341 address low_stack_addr = stack_base() - stack_size(); 342 MemTracker::release_thread_stack(low_stack_addr, stack_size(), this); 343#ifdef ASSERT 344 set_stack_base(NULL); 345#endif 346 } 347#endif // INCLUDE_NMT 348 349 // deallocate data structures 350 delete resource_area(); 351 // since the handle marks are using the handle area, we have to deallocated the root 352 // handle mark before deallocating the thread's handle area, 353 assert(last_handle_mark() != NULL, "check we have an element"); 354 delete last_handle_mark(); 355 assert(last_handle_mark() == NULL, "check we have reached the end"); 356 357 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 358 // We NULL out the fields for good hygiene. 359 ParkEvent::Release (_ParkEvent) ; _ParkEvent = NULL ; 360 ParkEvent::Release (_SleepEvent) ; _SleepEvent = NULL ; 361 ParkEvent::Release (_MutexEvent) ; _MutexEvent = NULL ; 362 ParkEvent::Release (_MuxEvent) ; _MuxEvent = NULL ; 363 364 delete handle_area(); 365 delete metadata_handles(); 366 367 // osthread() can be NULL, if creation of thread failed. 368 if (osthread() != NULL) os::free_thread(osthread()); 369 370 delete _SR_lock; 371 372 // clear thread local storage if the Thread is deleting itself 373 if (this == Thread::current()) { 374 ThreadLocalStorage::set_thread(NULL); 375 } else { 376 // In the case where we're not the current thread, invalidate all the 377 // caches in case some code tries to get the current thread or the 378 // thread that was destroyed, and gets stale information. 379 ThreadLocalStorage::invalidate_all(); 380 } 381 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 382} 383 384// NOTE: dummy function for assertion purpose. 385void Thread::run() { 386 ShouldNotReachHere(); 387} 388 389#ifdef ASSERT 390// Private method to check for dangling thread pointer 391void check_for_dangling_thread_pointer(Thread *thread) { 392 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 393 "possibility of dangling Thread pointer"); 394} 395#endif 396 397 398#ifndef PRODUCT 399// Tracing method for basic thread operations 400void Thread::trace(const char* msg, const Thread* const thread) { 401 if (!TraceThreadEvents) return; 402 ResourceMark rm; 403 ThreadCritical tc; 404 const char *name = "non-Java thread"; 405 int prio = -1; 406 if (thread->is_Java_thread() 407 && !thread->is_Compiler_thread()) { 408 // The Threads_lock must be held to get information about 409 // this thread but may not be in some situations when 410 // tracing thread events. 411 bool release_Threads_lock = false; 412 if (!Threads_lock->owned_by_self()) { 413 Threads_lock->lock(); 414 release_Threads_lock = true; 415 } 416 JavaThread* jt = (JavaThread *)thread; 417 name = (char *)jt->get_thread_name(); 418 oop thread_oop = jt->threadObj(); 419 if (thread_oop != NULL) { 420 prio = java_lang_Thread::priority(thread_oop); 421 } 422 if (release_Threads_lock) { 423 Threads_lock->unlock(); 424 } 425 } 426 tty->print_cr("Thread::%s " INTPTR_FORMAT " [%lx] %s (prio: %d)", msg, thread, thread->osthread()->thread_id(), name, prio); 427} 428#endif 429 430 431ThreadPriority Thread::get_priority(const Thread* const thread) { 432 trace("get priority", thread); 433 ThreadPriority priority; 434 // Can return an error! 435 (void)os::get_priority(thread, priority); 436 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 437 return priority; 438} 439 440void Thread::set_priority(Thread* thread, ThreadPriority priority) { 441 trace("set priority", thread); 442 debug_only(check_for_dangling_thread_pointer(thread);) 443 // Can return an error! 444 (void)os::set_priority(thread, priority); 445} 446 447 448void Thread::start(Thread* thread) { 449 trace("start", thread); 450 // Start is different from resume in that its safety is guaranteed by context or 451 // being called from a Java method synchronized on the Thread object. 452 if (!DisableStartThread) { 453 if (thread->is_Java_thread()) { 454 // Initialize the thread state to RUNNABLE before starting this thread. 455 // Can not set it after the thread started because we do not know the 456 // exact thread state at that time. It could be in MONITOR_WAIT or 457 // in SLEEPING or some other state. 458 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 459 java_lang_Thread::RUNNABLE); 460 } 461 os::start_thread(thread); 462 } 463} 464 465// Enqueue a VM_Operation to do the job for us - sometime later 466void Thread::send_async_exception(oop java_thread, oop java_throwable) { 467 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 468 VMThread::execute(vm_stop); 469} 470 471 472// 473// Check if an external suspend request has completed (or has been 474// cancelled). Returns true if the thread is externally suspended and 475// false otherwise. 476// 477// The bits parameter returns information about the code path through 478// the routine. Useful for debugging: 479// 480// set in is_ext_suspend_completed(): 481// 0x00000001 - routine was entered 482// 0x00000010 - routine return false at end 483// 0x00000100 - thread exited (return false) 484// 0x00000200 - suspend request cancelled (return false) 485// 0x00000400 - thread suspended (return true) 486// 0x00001000 - thread is in a suspend equivalent state (return true) 487// 0x00002000 - thread is native and walkable (return true) 488// 0x00004000 - thread is native_trans and walkable (needed retry) 489// 490// set in wait_for_ext_suspend_completion(): 491// 0x00010000 - routine was entered 492// 0x00020000 - suspend request cancelled before loop (return false) 493// 0x00040000 - thread suspended before loop (return true) 494// 0x00080000 - suspend request cancelled in loop (return false) 495// 0x00100000 - thread suspended in loop (return true) 496// 0x00200000 - suspend not completed during retry loop (return false) 497// 498 499// Helper class for tracing suspend wait debug bits. 500// 501// 0x00000100 indicates that the target thread exited before it could 502// self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 503// 0x00080000 each indicate a cancelled suspend request so they don't 504// count as wait failures either. 505#define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 506 507class TraceSuspendDebugBits : public StackObj { 508 private: 509 JavaThread * jt; 510 bool is_wait; 511 bool called_by_wait; // meaningful when !is_wait 512 uint32_t * bits; 513 514 public: 515 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 516 uint32_t *_bits) { 517 jt = _jt; 518 is_wait = _is_wait; 519 called_by_wait = _called_by_wait; 520 bits = _bits; 521 } 522 523 ~TraceSuspendDebugBits() { 524 if (!is_wait) { 525#if 1 526 // By default, don't trace bits for is_ext_suspend_completed() calls. 527 // That trace is very chatty. 528 return; 529#else 530 if (!called_by_wait) { 531 // If tracing for is_ext_suspend_completed() is enabled, then only 532 // trace calls to it from wait_for_ext_suspend_completion() 533 return; 534 } 535#endif 536 } 537 538 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 539 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 540 MutexLocker ml(Threads_lock); // needed for get_thread_name() 541 ResourceMark rm; 542 543 tty->print_cr( 544 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 545 jt->get_thread_name(), *bits); 546 547 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 548 } 549 } 550 } 551}; 552#undef DEBUG_FALSE_BITS 553 554 555bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits) { 556 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 557 558 bool did_trans_retry = false; // only do thread_in_native_trans retry once 559 bool do_trans_retry; // flag to force the retry 560 561 *bits |= 0x00000001; 562 563 do { 564 do_trans_retry = false; 565 566 if (is_exiting()) { 567 // Thread is in the process of exiting. This is always checked 568 // first to reduce the risk of dereferencing a freed JavaThread. 569 *bits |= 0x00000100; 570 return false; 571 } 572 573 if (!is_external_suspend()) { 574 // Suspend request is cancelled. This is always checked before 575 // is_ext_suspended() to reduce the risk of a rogue resume 576 // confusing the thread that made the suspend request. 577 *bits |= 0x00000200; 578 return false; 579 } 580 581 if (is_ext_suspended()) { 582 // thread is suspended 583 *bits |= 0x00000400; 584 return true; 585 } 586 587 // Now that we no longer do hard suspends of threads running 588 // native code, the target thread can be changing thread state 589 // while we are in this routine: 590 // 591 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 592 // 593 // We save a copy of the thread state as observed at this moment 594 // and make our decision about suspend completeness based on the 595 // copy. This closes the race where the thread state is seen as 596 // _thread_in_native_trans in the if-thread_blocked check, but is 597 // seen as _thread_blocked in if-thread_in_native_trans check. 598 JavaThreadState save_state = thread_state(); 599 600 if (save_state == _thread_blocked && is_suspend_equivalent()) { 601 // If the thread's state is _thread_blocked and this blocking 602 // condition is known to be equivalent to a suspend, then we can 603 // consider the thread to be externally suspended. This means that 604 // the code that sets _thread_blocked has been modified to do 605 // self-suspension if the blocking condition releases. We also 606 // used to check for CONDVAR_WAIT here, but that is now covered by 607 // the _thread_blocked with self-suspension check. 608 // 609 // Return true since we wouldn't be here unless there was still an 610 // external suspend request. 611 *bits |= 0x00001000; 612 return true; 613 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 614 // Threads running native code will self-suspend on native==>VM/Java 615 // transitions. If its stack is walkable (should always be the case 616 // unless this function is called before the actual java_suspend() 617 // call), then the wait is done. 618 *bits |= 0x00002000; 619 return true; 620 } else if (!called_by_wait && !did_trans_retry && 621 save_state == _thread_in_native_trans && 622 frame_anchor()->walkable()) { 623 // The thread is transitioning from thread_in_native to another 624 // thread state. check_safepoint_and_suspend_for_native_trans() 625 // will force the thread to self-suspend. If it hasn't gotten 626 // there yet we may have caught the thread in-between the native 627 // code check above and the self-suspend. Lucky us. If we were 628 // called by wait_for_ext_suspend_completion(), then it 629 // will be doing the retries so we don't have to. 630 // 631 // Since we use the saved thread state in the if-statement above, 632 // there is a chance that the thread has already transitioned to 633 // _thread_blocked by the time we get here. In that case, we will 634 // make a single unnecessary pass through the logic below. This 635 // doesn't hurt anything since we still do the trans retry. 636 637 *bits |= 0x00004000; 638 639 // Once the thread leaves thread_in_native_trans for another 640 // thread state, we break out of this retry loop. We shouldn't 641 // need this flag to prevent us from getting back here, but 642 // sometimes paranoia is good. 643 did_trans_retry = true; 644 645 // We wait for the thread to transition to a more usable state. 646 for (int i = 1; i <= SuspendRetryCount; i++) { 647 // We used to do an "os::yield_all(i)" call here with the intention 648 // that yielding would increase on each retry. However, the parameter 649 // is ignored on Linux which means the yield didn't scale up. Waiting 650 // on the SR_lock below provides a much more predictable scale up for 651 // the delay. It also provides a simple/direct point to check for any 652 // safepoint requests from the VMThread 653 654 // temporarily drops SR_lock while doing wait with safepoint check 655 // (if we're a JavaThread - the WatcherThread can also call this) 656 // and increase delay with each retry 657 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 658 659 // check the actual thread state instead of what we saved above 660 if (thread_state() != _thread_in_native_trans) { 661 // the thread has transitioned to another thread state so 662 // try all the checks (except this one) one more time. 663 do_trans_retry = true; 664 break; 665 } 666 } // end retry loop 667 668 669 } 670 } while (do_trans_retry); 671 672 *bits |= 0x00000010; 673 return false; 674} 675 676// 677// Wait for an external suspend request to complete (or be cancelled). 678// Returns true if the thread is externally suspended and false otherwise. 679// 680bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 681 uint32_t *bits) { 682 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 683 false /* !called_by_wait */, bits); 684 685 // local flag copies to minimize SR_lock hold time 686 bool is_suspended; 687 bool pending; 688 uint32_t reset_bits; 689 690 // set a marker so is_ext_suspend_completed() knows we are the caller 691 *bits |= 0x00010000; 692 693 // We use reset_bits to reinitialize the bits value at the top of 694 // each retry loop. This allows the caller to make use of any 695 // unused bits for their own marking purposes. 696 reset_bits = *bits; 697 698 { 699 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 700 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 701 delay, bits); 702 pending = is_external_suspend(); 703 } 704 // must release SR_lock to allow suspension to complete 705 706 if (!pending) { 707 // A cancelled suspend request is the only false return from 708 // is_ext_suspend_completed() that keeps us from entering the 709 // retry loop. 710 *bits |= 0x00020000; 711 return false; 712 } 713 714 if (is_suspended) { 715 *bits |= 0x00040000; 716 return true; 717 } 718 719 for (int i = 1; i <= retries; i++) { 720 *bits = reset_bits; // reinit to only track last retry 721 722 // We used to do an "os::yield_all(i)" call here with the intention 723 // that yielding would increase on each retry. However, the parameter 724 // is ignored on Linux which means the yield didn't scale up. Waiting 725 // on the SR_lock below provides a much more predictable scale up for 726 // the delay. It also provides a simple/direct point to check for any 727 // safepoint requests from the VMThread 728 729 { 730 MutexLocker ml(SR_lock()); 731 // wait with safepoint check (if we're a JavaThread - the WatcherThread 732 // can also call this) and increase delay with each retry 733 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 734 735 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 736 delay, bits); 737 738 // It is possible for the external suspend request to be cancelled 739 // (by a resume) before the actual suspend operation is completed. 740 // Refresh our local copy to see if we still need to wait. 741 pending = is_external_suspend(); 742 } 743 744 if (!pending) { 745 // A cancelled suspend request is the only false return from 746 // is_ext_suspend_completed() that keeps us from staying in the 747 // retry loop. 748 *bits |= 0x00080000; 749 return false; 750 } 751 752 if (is_suspended) { 753 *bits |= 0x00100000; 754 return true; 755 } 756 } // end retry loop 757 758 // thread did not suspend after all our retries 759 *bits |= 0x00200000; 760 return false; 761} 762 763#ifndef PRODUCT 764void JavaThread::record_jump(address target, address instr, const char* file, int line) { 765 766 // This should not need to be atomic as the only way for simultaneous 767 // updates is via interrupts. Even then this should be rare or non-existant 768 // and we don't care that much anyway. 769 770 int index = _jmp_ring_index; 771 _jmp_ring_index = (index + 1 ) & (jump_ring_buffer_size - 1); 772 _jmp_ring[index]._target = (intptr_t) target; 773 _jmp_ring[index]._instruction = (intptr_t) instr; 774 _jmp_ring[index]._file = file; 775 _jmp_ring[index]._line = line; 776} 777#endif /* PRODUCT */ 778 779// Called by flat profiler 780// Callers have already called wait_for_ext_suspend_completion 781// The assertion for that is currently too complex to put here: 782bool JavaThread::profile_last_Java_frame(frame* _fr) { 783 bool gotframe = false; 784 // self suspension saves needed state. 785 if (has_last_Java_frame() && _anchor.walkable()) { 786 *_fr = pd_last_frame(); 787 gotframe = true; 788 } 789 return gotframe; 790} 791 792void Thread::interrupt(Thread* thread) { 793 trace("interrupt", thread); 794 debug_only(check_for_dangling_thread_pointer(thread);) 795 os::interrupt(thread); 796} 797 798bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 799 trace("is_interrupted", thread); 800 debug_only(check_for_dangling_thread_pointer(thread);) 801 // Note: If clear_interrupted==false, this simply fetches and 802 // returns the value of the field osthread()->interrupted(). 803 return os::is_interrupted(thread, clear_interrupted); 804} 805 806 807// GC Support 808bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 809 jint thread_parity = _oops_do_parity; 810 if (thread_parity != strong_roots_parity) { 811 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 812 if (res == thread_parity) { 813 return true; 814 } else { 815 guarantee(res == strong_roots_parity, "Or else what?"); 816 assert(SharedHeap::heap()->workers()->active_workers() > 0, 817 "Should only fail when parallel."); 818 return false; 819 } 820 } 821 assert(SharedHeap::heap()->workers()->active_workers() > 0, 822 "Should only fail when parallel."); 823 return false; 824} 825 826void Thread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 827 active_handles()->oops_do(f); 828 // Do oop for ThreadShadow 829 f->do_oop((oop*)&_pending_exception); 830 handle_area()->oops_do(f); 831} 832 833void Thread::nmethods_do(CodeBlobClosure* cf) { 834 // no nmethods in a generic thread... 835} 836 837void Thread::metadata_do(void f(Metadata*)) { 838 if (metadata_handles() != NULL) { 839 for (int i = 0; i< metadata_handles()->length(); i++) { 840 f(metadata_handles()->at(i)); 841 } 842 } 843} 844 845void Thread::print_on(outputStream* st) const { 846 // get_priority assumes osthread initialized 847 if (osthread() != NULL) { 848 int os_prio; 849 if (os::get_native_priority(this, &os_prio) == OS_OK) { 850 st->print("os_prio=%d ", os_prio); 851 } 852 st->print("tid=" INTPTR_FORMAT " ", this); 853 osthread()->print_on(st); 854 } 855 debug_only(if (WizardMode) print_owned_locks_on(st);) 856} 857 858// Thread::print_on_error() is called by fatal error handler. Don't use 859// any lock or allocate memory. 860void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 861 if (is_VM_thread()) st->print("VMThread"); 862 else if (is_Compiler_thread()) st->print("CompilerThread"); 863 else if (is_Java_thread()) st->print("JavaThread"); 864 else if (is_GC_task_thread()) st->print("GCTaskThread"); 865 else if (is_Watcher_thread()) st->print("WatcherThread"); 866 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 867 else st->print("Thread"); 868 869 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 870 _stack_base - _stack_size, _stack_base); 871 872 if (osthread()) { 873 st->print(" [id=%d]", osthread()->thread_id()); 874 } 875} 876 877#ifdef ASSERT 878void Thread::print_owned_locks_on(outputStream* st) const { 879 Monitor *cur = _owned_locks; 880 if (cur == NULL) { 881 st->print(" (no locks) "); 882 } else { 883 st->print_cr(" Locks owned:"); 884 while(cur) { 885 cur->print_on(st); 886 cur = cur->next(); 887 } 888 } 889} 890 891static int ref_use_count = 0; 892 893bool Thread::owns_locks_but_compiled_lock() const { 894 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 895 if (cur != Compile_lock) return true; 896 } 897 return false; 898} 899 900 901#endif 902 903#ifndef PRODUCT 904 905// The flag: potential_vm_operation notifies if this particular safepoint state could potential 906// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 907// no threads which allow_vm_block's are held 908void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 909 // Check if current thread is allowed to block at a safepoint 910 if (!(_allow_safepoint_count == 0)) 911 fatal("Possible safepoint reached by thread that does not allow it"); 912 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 913 fatal("LEAF method calling lock?"); 914 } 915 916#ifdef ASSERT 917 if (potential_vm_operation && is_Java_thread() 918 && !Universe::is_bootstrapping()) { 919 // Make sure we do not hold any locks that the VM thread also uses. 920 // This could potentially lead to deadlocks 921 for(Monitor *cur = _owned_locks; cur; cur = cur->next()) { 922 // Threads_lock is special, since the safepoint synchronization will not start before this is 923 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 924 // since it is used to transfer control between JavaThreads and the VMThread 925 // Do not *exclude* any locks unless you are absolutly sure it is correct. Ask someone else first! 926 if ( (cur->allow_vm_block() && 927 cur != Threads_lock && 928 cur != Compile_lock && // Temporary: should not be necessary when we get spearate compilation 929 cur != VMOperationRequest_lock && 930 cur != VMOperationQueue_lock) || 931 cur->rank() == Mutex::special) { 932 warning("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 933 } 934 } 935 } 936 937 if (GCALotAtAllSafepoints) { 938 // We could enter a safepoint here and thus have a gc 939 InterfaceSupport::check_gc_alot(); 940 } 941#endif 942} 943#endif 944 945bool Thread::is_in_stack(address adr) const { 946 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 947 address end = os::current_stack_pointer(); 948 // Allow non Java threads to call this without stack_base 949 if (_stack_base == NULL) return true; 950 if (stack_base() >= adr && adr >= end) return true; 951 952 return false; 953} 954 955 956// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 957// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 958// used for compilation in the future. If that change is made, the need for these methods 959// should be revisited, and they should be removed if possible. 960 961bool Thread::is_lock_owned(address adr) const { 962 return on_local_stack(adr); 963} 964 965bool Thread::set_as_starting_thread() { 966 // NOTE: this must be called inside the main thread. 967 return os::create_main_thread((JavaThread*)this); 968} 969 970static void initialize_class(Symbol* class_name, TRAPS) { 971 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 972 InstanceKlass::cast(klass)->initialize(CHECK); 973} 974 975 976// Creates the initial ThreadGroup 977static Handle create_initial_thread_group(TRAPS) { 978 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 979 instanceKlassHandle klass (THREAD, k); 980 981 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 982 { 983 JavaValue result(T_VOID); 984 JavaCalls::call_special(&result, 985 system_instance, 986 klass, 987 vmSymbols::object_initializer_name(), 988 vmSymbols::void_method_signature(), 989 CHECK_NH); 990 } 991 Universe::set_system_thread_group(system_instance()); 992 993 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 994 { 995 JavaValue result(T_VOID); 996 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 997 JavaCalls::call_special(&result, 998 main_instance, 999 klass, 1000 vmSymbols::object_initializer_name(), 1001 vmSymbols::threadgroup_string_void_signature(), 1002 system_instance, 1003 string, 1004 CHECK_NH); 1005 } 1006 return main_instance; 1007} 1008 1009// Creates the initial Thread 1010static oop create_initial_thread(Handle thread_group, JavaThread* thread, TRAPS) { 1011 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 1012 instanceKlassHandle klass (THREAD, k); 1013 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 1014 1015 java_lang_Thread::set_thread(thread_oop(), thread); 1016 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1017 thread->set_threadObj(thread_oop()); 1018 1019 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 1020 1021 JavaValue result(T_VOID); 1022 JavaCalls::call_special(&result, thread_oop, 1023 klass, 1024 vmSymbols::object_initializer_name(), 1025 vmSymbols::threadgroup_string_void_signature(), 1026 thread_group, 1027 string, 1028 CHECK_NULL); 1029 return thread_oop(); 1030} 1031 1032static void call_initializeSystemClass(TRAPS) { 1033 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1034 instanceKlassHandle klass (THREAD, k); 1035 1036 JavaValue result(T_VOID); 1037 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1038 vmSymbols::void_method_signature(), CHECK); 1039} 1040 1041char java_runtime_name[128] = ""; 1042char java_runtime_version[128] = ""; 1043 1044// extract the JRE name from sun.misc.Version.java_runtime_name 1045static const char* get_java_runtime_name(TRAPS) { 1046 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1047 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1048 fieldDescriptor fd; 1049 bool found = k != NULL && 1050 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1051 vmSymbols::string_signature(), &fd); 1052 if (found) { 1053 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1054 if (name_oop == NULL) 1055 return NULL; 1056 const char* name = java_lang_String::as_utf8_string(name_oop, 1057 java_runtime_name, 1058 sizeof(java_runtime_name)); 1059 return name; 1060 } else { 1061 return NULL; 1062 } 1063} 1064 1065// extract the JRE version from sun.misc.Version.java_runtime_version 1066static const char* get_java_runtime_version(TRAPS) { 1067 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1068 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1069 fieldDescriptor fd; 1070 bool found = k != NULL && 1071 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1072 vmSymbols::string_signature(), &fd); 1073 if (found) { 1074 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1075 if (name_oop == NULL) 1076 return NULL; 1077 const char* name = java_lang_String::as_utf8_string(name_oop, 1078 java_runtime_version, 1079 sizeof(java_runtime_version)); 1080 return name; 1081 } else { 1082 return NULL; 1083 } 1084} 1085 1086// General purpose hook into Java code, run once when the VM is initialized. 1087// The Java library method itself may be changed independently from the VM. 1088static void call_postVMInitHook(TRAPS) { 1089 Klass* k = SystemDictionary::PostVMInitHook_klass(); 1090 instanceKlassHandle klass (THREAD, k); 1091 if (klass.not_null()) { 1092 JavaValue result(T_VOID); 1093 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1094 vmSymbols::void_method_signature(), 1095 CHECK); 1096 } 1097} 1098 1099static void reset_vm_info_property(TRAPS) { 1100 // the vm info string 1101 ResourceMark rm(THREAD); 1102 const char *vm_info = VM_Version::vm_info_string(); 1103 1104 // java.lang.System class 1105 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1106 instanceKlassHandle klass (THREAD, k); 1107 1108 // setProperty arguments 1109 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1110 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1111 1112 // return value 1113 JavaValue r(T_OBJECT); 1114 1115 // public static String setProperty(String key, String value); 1116 JavaCalls::call_static(&r, 1117 klass, 1118 vmSymbols::setProperty_name(), 1119 vmSymbols::string_string_string_signature(), 1120 key_str, 1121 value_str, 1122 CHECK); 1123} 1124 1125 1126void JavaThread::allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS) { 1127 assert(thread_group.not_null(), "thread group should be specified"); 1128 assert(threadObj() == NULL, "should only create Java thread object once"); 1129 1130 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1131 instanceKlassHandle klass (THREAD, k); 1132 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1133 1134 java_lang_Thread::set_thread(thread_oop(), this); 1135 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1136 set_threadObj(thread_oop()); 1137 1138 JavaValue result(T_VOID); 1139 if (thread_name != NULL) { 1140 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1141 // Thread gets assigned specified name and null target 1142 JavaCalls::call_special(&result, 1143 thread_oop, 1144 klass, 1145 vmSymbols::object_initializer_name(), 1146 vmSymbols::threadgroup_string_void_signature(), 1147 thread_group, // Argument 1 1148 name, // Argument 2 1149 THREAD); 1150 } else { 1151 // Thread gets assigned name "Thread-nnn" and null target 1152 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1153 JavaCalls::call_special(&result, 1154 thread_oop, 1155 klass, 1156 vmSymbols::object_initializer_name(), 1157 vmSymbols::threadgroup_runnable_void_signature(), 1158 thread_group, // Argument 1 1159 Handle(), // Argument 2 1160 THREAD); 1161 } 1162 1163 1164 if (daemon) { 1165 java_lang_Thread::set_daemon(thread_oop()); 1166 } 1167 1168 if (HAS_PENDING_EXCEPTION) { 1169 return; 1170 } 1171 1172 KlassHandle group(this, SystemDictionary::ThreadGroup_klass()); 1173 Handle threadObj(this, this->threadObj()); 1174 1175 JavaCalls::call_special(&result, 1176 thread_group, 1177 group, 1178 vmSymbols::add_method_name(), 1179 vmSymbols::thread_void_signature(), 1180 threadObj, // Arg 1 1181 THREAD); 1182 1183 1184} 1185 1186// NamedThread -- non-JavaThread subclasses with multiple 1187// uniquely named instances should derive from this. 1188NamedThread::NamedThread() : Thread() { 1189 _name = NULL; 1190 _processed_thread = NULL; 1191} 1192 1193NamedThread::~NamedThread() { 1194 if (_name != NULL) { 1195 FREE_C_HEAP_ARRAY(char, _name, mtThread); 1196 _name = NULL; 1197 } 1198} 1199 1200void NamedThread::set_name(const char* format, ...) { 1201 guarantee(_name == NULL, "Only get to set name once."); 1202 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1203 guarantee(_name != NULL, "alloc failure"); 1204 va_list ap; 1205 va_start(ap, format); 1206 jio_vsnprintf(_name, max_name_len, format, ap); 1207 va_end(ap); 1208} 1209 1210// ======= WatcherThread ======== 1211 1212// The watcher thread exists to simulate timer interrupts. It should 1213// be replaced by an abstraction over whatever native support for 1214// timer interrupts exists on the platform. 1215 1216WatcherThread* WatcherThread::_watcher_thread = NULL; 1217bool WatcherThread::_startable = false; 1218volatile bool WatcherThread::_should_terminate = false; 1219 1220WatcherThread::WatcherThread() : Thread() { 1221 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1222 if (os::create_thread(this, os::watcher_thread)) { 1223 _watcher_thread = this; 1224 1225 // Set the watcher thread to the highest OS priority which should not be 1226 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1227 // is created. The only normal thread using this priority is the reference 1228 // handler thread, which runs for very short intervals only. 1229 // If the VMThread's priority is not lower than the WatcherThread profiling 1230 // will be inaccurate. 1231 os::set_priority(this, MaxPriority); 1232 if (!DisableStartThread) { 1233 os::start_thread(this); 1234 } 1235 } 1236} 1237 1238int WatcherThread::sleep() const { 1239 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1240 1241 // remaining will be zero if there are no tasks, 1242 // causing the WatcherThread to sleep until a task is 1243 // enrolled 1244 int remaining = PeriodicTask::time_to_wait(); 1245 int time_slept = 0; 1246 1247 // we expect this to timeout - we only ever get unparked when 1248 // we should terminate or when a new task has been enrolled 1249 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1250 1251 jlong time_before_loop = os::javaTimeNanos(); 1252 1253 for (;;) { 1254 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, remaining); 1255 jlong now = os::javaTimeNanos(); 1256 1257 if (remaining == 0) { 1258 // if we didn't have any tasks we could have waited for a long time 1259 // consider the time_slept zero and reset time_before_loop 1260 time_slept = 0; 1261 time_before_loop = now; 1262 } else { 1263 // need to recalulate since we might have new tasks in _tasks 1264 time_slept = (int) ((now - time_before_loop) / 1000000); 1265 } 1266 1267 // Change to task list or spurious wakeup of some kind 1268 if (timedout || _should_terminate) { 1269 break; 1270 } 1271 1272 remaining = PeriodicTask::time_to_wait(); 1273 if (remaining == 0) { 1274 // Last task was just disenrolled so loop around and wait until 1275 // another task gets enrolled 1276 continue; 1277 } 1278 1279 remaining -= time_slept; 1280 if (remaining <= 0) 1281 break; 1282 } 1283 1284 return time_slept; 1285} 1286 1287void WatcherThread::run() { 1288 assert(this == watcher_thread(), "just checking"); 1289 1290 this->record_stack_base_and_size(); 1291 this->initialize_thread_local_storage(); 1292 this->set_active_handles(JNIHandleBlock::allocate_block()); 1293 while(!_should_terminate) { 1294 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1295 assert(watcher_thread() == this, "thread consistency check"); 1296 1297 // Calculate how long it'll be until the next PeriodicTask work 1298 // should be done, and sleep that amount of time. 1299 int time_waited = sleep(); 1300 1301 if (is_error_reported()) { 1302 // A fatal error has happened, the error handler(VMError::report_and_die) 1303 // should abort JVM after creating an error log file. However in some 1304 // rare cases, the error handler itself might deadlock. Here we try to 1305 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1306 // 1307 // This code is in WatcherThread because WatcherThread wakes up 1308 // periodically so the fatal error handler doesn't need to do anything; 1309 // also because the WatcherThread is less likely to crash than other 1310 // threads. 1311 1312 for (;;) { 1313 if (!ShowMessageBoxOnError 1314 && (OnError == NULL || OnError[0] == '\0') 1315 && Arguments::abort_hook() == NULL) { 1316 os::sleep(this, 2 * 60 * 1000, false); 1317 fdStream err(defaultStream::output_fd()); 1318 err.print_raw_cr("# [ timer expired, abort... ]"); 1319 // skip atexit/vm_exit/vm_abort hooks 1320 os::die(); 1321 } 1322 1323 // Wake up 5 seconds later, the fatal handler may reset OnError or 1324 // ShowMessageBoxOnError when it is ready to abort. 1325 os::sleep(this, 5 * 1000, false); 1326 } 1327 } 1328 1329 PeriodicTask::real_time_tick(time_waited); 1330 } 1331 1332 // Signal that it is terminated 1333 { 1334 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1335 _watcher_thread = NULL; 1336 Terminator_lock->notify(); 1337 } 1338 1339 // Thread destructor usually does this.. 1340 ThreadLocalStorage::set_thread(NULL); 1341} 1342 1343void WatcherThread::start() { 1344 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1345 1346 if (watcher_thread() == NULL && _startable) { 1347 _should_terminate = false; 1348 // Create the single instance of WatcherThread 1349 new WatcherThread(); 1350 } 1351} 1352 1353void WatcherThread::make_startable() { 1354 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1355 _startable = true; 1356} 1357 1358void WatcherThread::stop() { 1359 { 1360 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1361 _should_terminate = true; 1362 OrderAccess::fence(); // ensure WatcherThread sees update in main loop 1363 1364 WatcherThread* watcher = watcher_thread(); 1365 if (watcher != NULL) 1366 watcher->unpark(); 1367 } 1368 1369 // it is ok to take late safepoints here, if needed 1370 MutexLocker mu(Terminator_lock); 1371 1372 while(watcher_thread() != NULL) { 1373 // This wait should make safepoint checks, wait without a timeout, 1374 // and wait as a suspend-equivalent condition. 1375 // 1376 // Note: If the FlatProfiler is running, then this thread is waiting 1377 // for the WatcherThread to terminate and the WatcherThread, via the 1378 // FlatProfiler task, is waiting for the external suspend request on 1379 // this thread to complete. wait_for_ext_suspend_completion() will 1380 // eventually timeout, but that takes time. Making this wait a 1381 // suspend-equivalent condition solves that timeout problem. 1382 // 1383 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1384 Mutex::_as_suspend_equivalent_flag); 1385 } 1386} 1387 1388void WatcherThread::unpark() { 1389 MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1390 PeriodicTask_lock->notify(); 1391} 1392 1393void WatcherThread::print_on(outputStream* st) const { 1394 st->print("\"%s\" ", name()); 1395 Thread::print_on(st); 1396 st->cr(); 1397} 1398 1399// ======= JavaThread ======== 1400 1401// A JavaThread is a normal Java thread 1402 1403void JavaThread::initialize() { 1404 // Initialize fields 1405 1406 // Set the claimed par_id to -1 (ie not claiming any par_ids) 1407 set_claimed_par_id(-1); 1408 1409 set_saved_exception_pc(NULL); 1410 set_threadObj(NULL); 1411 _anchor.clear(); 1412 set_entry_point(NULL); 1413 set_jni_functions(jni_functions()); 1414 set_callee_target(NULL); 1415 set_vm_result(NULL); 1416 set_vm_result_2(NULL); 1417 set_vframe_array_head(NULL); 1418 set_vframe_array_last(NULL); 1419 set_deferred_locals(NULL); 1420 set_deopt_mark(NULL); 1421 set_deopt_nmethod(NULL); 1422 clear_must_deopt_id(); 1423 set_monitor_chunks(NULL); 1424 set_next(NULL); 1425 set_thread_state(_thread_new); 1426#if INCLUDE_NMT 1427 set_recorder(NULL); 1428#endif 1429 _terminated = _not_terminated; 1430 _privileged_stack_top = NULL; 1431 _array_for_gc = NULL; 1432 _suspend_equivalent = false; 1433 _in_deopt_handler = 0; 1434 _doing_unsafe_access = false; 1435 _stack_guard_state = stack_guard_unused; 1436 _exception_oop = NULL; 1437 _exception_pc = 0; 1438 _exception_handler_pc = 0; 1439 _is_method_handle_return = 0; 1440 _jvmti_thread_state= NULL; 1441 _should_post_on_exceptions_flag = JNI_FALSE; 1442 _jvmti_get_loaded_classes_closure = NULL; 1443 _interp_only_mode = 0; 1444 _special_runtime_exit_condition = _no_async_condition; 1445 _pending_async_exception = NULL; 1446 _is_compiling = false; 1447 _thread_stat = NULL; 1448 _thread_stat = new ThreadStatistics(); 1449 _blocked_on_compilation = false; 1450 _jni_active_critical = 0; 1451 _do_not_unlock_if_synchronized = false; 1452 _cached_monitor_info = NULL; 1453 _parker = Parker::Allocate(this) ; 1454 1455#ifndef PRODUCT 1456 _jmp_ring_index = 0; 1457 for (int ji = 0 ; ji < jump_ring_buffer_size ; ji++ ) { 1458 record_jump(NULL, NULL, NULL, 0); 1459 } 1460#endif /* PRODUCT */ 1461 1462 set_thread_profiler(NULL); 1463 if (FlatProfiler::is_active()) { 1464 // This is where we would decide to either give each thread it's own profiler 1465 // or use one global one from FlatProfiler, 1466 // or up to some count of the number of profiled threads, etc. 1467 ThreadProfiler* pp = new ThreadProfiler(); 1468 pp->engage(); 1469 set_thread_profiler(pp); 1470 } 1471 1472 // Setup safepoint state info for this thread 1473 ThreadSafepointState::create(this); 1474 1475 debug_only(_java_call_counter = 0); 1476 1477 // JVMTI PopFrame support 1478 _popframe_condition = popframe_inactive; 1479 _popframe_preserved_args = NULL; 1480 _popframe_preserved_args_size = 0; 1481 1482 pd_initialize(); 1483} 1484 1485#ifndef SERIALGC 1486SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1487DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1488#endif // !SERIALGC 1489 1490JavaThread::JavaThread(bool is_attaching_via_jni) : 1491 Thread() 1492#ifndef SERIALGC 1493 , _satb_mark_queue(&_satb_mark_queue_set), 1494 _dirty_card_queue(&_dirty_card_queue_set) 1495#endif // !SERIALGC 1496{ 1497 initialize(); 1498 if (is_attaching_via_jni) { 1499 _jni_attach_state = _attaching_via_jni; 1500 } else { 1501 _jni_attach_state = _not_attaching_via_jni; 1502 } 1503 assert(_deferred_card_mark.is_empty(), "Default MemRegion ctor"); 1504 _safepoint_visible = false; 1505} 1506 1507bool JavaThread::reguard_stack(address cur_sp) { 1508 if (_stack_guard_state != stack_guard_yellow_disabled) { 1509 return true; // Stack already guarded or guard pages not needed. 1510 } 1511 1512 if (register_stack_overflow()) { 1513 // For those architectures which have separate register and 1514 // memory stacks, we must check the register stack to see if 1515 // it has overflowed. 1516 return false; 1517 } 1518 1519 // Java code never executes within the yellow zone: the latter is only 1520 // there to provoke an exception during stack banging. If java code 1521 // is executing there, either StackShadowPages should be larger, or 1522 // some exception code in c1, c2 or the interpreter isn't unwinding 1523 // when it should. 1524 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1525 1526 enable_stack_yellow_zone(); 1527 return true; 1528} 1529 1530bool JavaThread::reguard_stack(void) { 1531 return reguard_stack(os::current_stack_pointer()); 1532} 1533 1534 1535void JavaThread::block_if_vm_exited() { 1536 if (_terminated == _vm_exited) { 1537 // _vm_exited is set at safepoint, and Threads_lock is never released 1538 // we will block here forever 1539 Threads_lock->lock_without_safepoint_check(); 1540 ShouldNotReachHere(); 1541 } 1542} 1543 1544 1545// Remove this ifdef when C1 is ported to the compiler interface. 1546static void compiler_thread_entry(JavaThread* thread, TRAPS); 1547 1548JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1549 Thread() 1550#ifndef SERIALGC 1551 , _satb_mark_queue(&_satb_mark_queue_set), 1552 _dirty_card_queue(&_dirty_card_queue_set) 1553#endif // !SERIALGC 1554{ 1555 if (TraceThreadEvents) { 1556 tty->print_cr("creating thread %p", this); 1557 } 1558 initialize(); 1559 _jni_attach_state = _not_attaching_via_jni; 1560 set_entry_point(entry_point); 1561 // Create the native thread itself. 1562 // %note runtime_23 1563 os::ThreadType thr_type = os::java_thread; 1564 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1565 os::java_thread; 1566 os::create_thread(this, thr_type, stack_sz); 1567 _safepoint_visible = false; 1568 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1569 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1570 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1571 // the exception consists of creating the exception object & initializing it, initialization 1572 // will leave the VM via a JavaCall and then all locks must be unlocked). 1573 // 1574 // The thread is still suspended when we reach here. Thread must be explicit started 1575 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1576 // by calling Threads:add. The reason why this is not done here, is because the thread 1577 // object must be fully initialized (take a look at JVM_Start) 1578} 1579 1580JavaThread::~JavaThread() { 1581 if (TraceThreadEvents) { 1582 tty->print_cr("terminate thread %p", this); 1583 } 1584 1585 // By now, this thread should already be invisible to safepoint, 1586 // and its per-thread recorder also collected. 1587 assert(!is_safepoint_visible(), "wrong state"); 1588#if INCLUDE_NMT 1589 assert(get_recorder() == NULL, "Already collected"); 1590#endif // INCLUDE_NMT 1591 1592 // JSR166 -- return the parker to the free list 1593 Parker::Release(_parker); 1594 _parker = NULL ; 1595 1596 // Free any remaining previous UnrollBlock 1597 vframeArray* old_array = vframe_array_last(); 1598 1599 if (old_array != NULL) { 1600 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1601 old_array->set_unroll_block(NULL); 1602 delete old_info; 1603 delete old_array; 1604 } 1605 1606 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1607 if (deferred != NULL) { 1608 // This can only happen if thread is destroyed before deoptimization occurs. 1609 assert(deferred->length() != 0, "empty array!"); 1610 do { 1611 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1612 deferred->remove_at(0); 1613 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1614 delete dlv; 1615 } while (deferred->length() != 0); 1616 delete deferred; 1617 } 1618 1619 // All Java related clean up happens in exit 1620 ThreadSafepointState::destroy(this); 1621 if (_thread_profiler != NULL) delete _thread_profiler; 1622 if (_thread_stat != NULL) delete _thread_stat; 1623} 1624 1625 1626// The first routine called by a new Java thread 1627void JavaThread::run() { 1628 // initialize thread-local alloc buffer related fields 1629 this->initialize_tlab(); 1630 1631 // used to test validitity of stack trace backs 1632 this->record_base_of_stack_pointer(); 1633 1634 // Record real stack base and size. 1635 this->record_stack_base_and_size(); 1636 1637 // Initialize thread local storage; set before calling MutexLocker 1638 this->initialize_thread_local_storage(); 1639 1640 this->create_stack_guard_pages(); 1641 1642 this->cache_global_variables(); 1643 1644 // Thread is now sufficient initialized to be handled by the safepoint code as being 1645 // in the VM. Change thread state from _thread_new to _thread_in_vm 1646 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1647 1648 assert(JavaThread::current() == this, "sanity check"); 1649 assert(!Thread::current()->owns_locks(), "sanity check"); 1650 1651 DTRACE_THREAD_PROBE(start, this); 1652 1653 // This operation might block. We call that after all safepoint checks for a new thread has 1654 // been completed. 1655 this->set_active_handles(JNIHandleBlock::allocate_block()); 1656 1657 if (JvmtiExport::should_post_thread_life()) { 1658 JvmtiExport::post_thread_start(this); 1659 } 1660 1661 EVENT_BEGIN(TraceEventThreadStart, event); 1662 EVENT_COMMIT(event, 1663 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj()))); 1664 1665 // We call another function to do the rest so we are sure that the stack addresses used 1666 // from there will be lower than the stack base just computed 1667 thread_main_inner(); 1668 1669 // Note, thread is no longer valid at this point! 1670} 1671 1672 1673void JavaThread::thread_main_inner() { 1674 assert(JavaThread::current() == this, "sanity check"); 1675 assert(this->threadObj() != NULL, "just checking"); 1676 1677 // Execute thread entry point unless this thread has a pending exception 1678 // or has been stopped before starting. 1679 // Note: Due to JVM_StopThread we can have pending exceptions already! 1680 if (!this->has_pending_exception() && 1681 !java_lang_Thread::is_stillborn(this->threadObj())) { 1682 { 1683 ResourceMark rm(this); 1684 this->set_native_thread_name(this->get_thread_name()); 1685 } 1686 HandleMark hm(this); 1687 this->entry_point()(this, this); 1688 } 1689 1690 DTRACE_THREAD_PROBE(stop, this); 1691 1692 this->exit(false); 1693 delete this; 1694} 1695 1696 1697static void ensure_join(JavaThread* thread) { 1698 // We do not need to grap the Threads_lock, since we are operating on ourself. 1699 Handle threadObj(thread, thread->threadObj()); 1700 assert(threadObj.not_null(), "java thread object must exist"); 1701 ObjectLocker lock(threadObj, thread); 1702 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1703 thread->clear_pending_exception(); 1704 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1705 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1706 // Clear the native thread instance - this makes isAlive return false and allows the join() 1707 // to complete once we've done the notify_all below 1708 java_lang_Thread::set_thread(threadObj(), NULL); 1709 lock.notify_all(thread); 1710 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1711 thread->clear_pending_exception(); 1712} 1713 1714 1715// For any new cleanup additions, please check to see if they need to be applied to 1716// cleanup_failed_attach_current_thread as well. 1717void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1718 assert(this == JavaThread::current(), "thread consistency check"); 1719 if (!InitializeJavaLangSystem) return; 1720 1721 HandleMark hm(this); 1722 Handle uncaught_exception(this, this->pending_exception()); 1723 this->clear_pending_exception(); 1724 Handle threadObj(this, this->threadObj()); 1725 assert(threadObj.not_null(), "Java thread object should be created"); 1726 1727 if (get_thread_profiler() != NULL) { 1728 get_thread_profiler()->disengage(); 1729 ResourceMark rm; 1730 get_thread_profiler()->print(get_thread_name()); 1731 } 1732 1733 1734 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1735 { 1736 EXCEPTION_MARK; 1737 1738 CLEAR_PENDING_EXCEPTION; 1739 } 1740 // FIXIT: The is_null check is only so it works better on JDK1.2 VM's. This 1741 // has to be fixed by a runtime query method 1742 if (!destroy_vm || JDK_Version::is_jdk12x_version()) { 1743 // JSR-166: change call from from ThreadGroup.uncaughtException to 1744 // java.lang.Thread.dispatchUncaughtException 1745 if (uncaught_exception.not_null()) { 1746 Handle group(this, java_lang_Thread::threadGroup(threadObj())); 1747 { 1748 EXCEPTION_MARK; 1749 // Check if the method Thread.dispatchUncaughtException() exists. If so 1750 // call it. Otherwise we have an older library without the JSR-166 changes, 1751 // so call ThreadGroup.uncaughtException() 1752 KlassHandle recvrKlass(THREAD, threadObj->klass()); 1753 CallInfo callinfo; 1754 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1755 LinkResolver::resolve_virtual_call(callinfo, threadObj, recvrKlass, thread_klass, 1756 vmSymbols::dispatchUncaughtException_name(), 1757 vmSymbols::throwable_void_signature(), 1758 KlassHandle(), false, false, THREAD); 1759 CLEAR_PENDING_EXCEPTION; 1760 methodHandle method = callinfo.selected_method(); 1761 if (method.not_null()) { 1762 JavaValue result(T_VOID); 1763 JavaCalls::call_virtual(&result, 1764 threadObj, thread_klass, 1765 vmSymbols::dispatchUncaughtException_name(), 1766 vmSymbols::throwable_void_signature(), 1767 uncaught_exception, 1768 THREAD); 1769 } else { 1770 KlassHandle thread_group(THREAD, SystemDictionary::ThreadGroup_klass()); 1771 JavaValue result(T_VOID); 1772 JavaCalls::call_virtual(&result, 1773 group, thread_group, 1774 vmSymbols::uncaughtException_name(), 1775 vmSymbols::thread_throwable_void_signature(), 1776 threadObj, // Arg 1 1777 uncaught_exception, // Arg 2 1778 THREAD); 1779 } 1780 if (HAS_PENDING_EXCEPTION) { 1781 ResourceMark rm(this); 1782 jio_fprintf(defaultStream::error_stream(), 1783 "\nException: %s thrown from the UncaughtExceptionHandler" 1784 " in thread \"%s\"\n", 1785 pending_exception()->klass()->external_name(), 1786 get_thread_name()); 1787 CLEAR_PENDING_EXCEPTION; 1788 } 1789 } 1790 } 1791 1792 // Called before the java thread exit since we want to read info 1793 // from java_lang_Thread object 1794 EVENT_BEGIN(TraceEventThreadEnd, event); 1795 EVENT_COMMIT(event, 1796 EVENT_SET(event, javalangthread, java_lang_Thread::thread_id(this->threadObj()))); 1797 1798 // Call after last event on thread 1799 EVENT_THREAD_EXIT(this); 1800 1801 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1802 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1803 // is deprecated anyhow. 1804 { int count = 3; 1805 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1806 EXCEPTION_MARK; 1807 JavaValue result(T_VOID); 1808 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1809 JavaCalls::call_virtual(&result, 1810 threadObj, thread_klass, 1811 vmSymbols::exit_method_name(), 1812 vmSymbols::void_method_signature(), 1813 THREAD); 1814 CLEAR_PENDING_EXCEPTION; 1815 } 1816 } 1817 1818 // notify JVMTI 1819 if (JvmtiExport::should_post_thread_life()) { 1820 JvmtiExport::post_thread_end(this); 1821 } 1822 1823 // We have notified the agents that we are exiting, before we go on, 1824 // we must check for a pending external suspend request and honor it 1825 // in order to not surprise the thread that made the suspend request. 1826 while (true) { 1827 { 1828 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1829 if (!is_external_suspend()) { 1830 set_terminated(_thread_exiting); 1831 ThreadService::current_thread_exiting(this); 1832 break; 1833 } 1834 // Implied else: 1835 // Things get a little tricky here. We have a pending external 1836 // suspend request, but we are holding the SR_lock so we 1837 // can't just self-suspend. So we temporarily drop the lock 1838 // and then self-suspend. 1839 } 1840 1841 ThreadBlockInVM tbivm(this); 1842 java_suspend_self(); 1843 1844 // We're done with this suspend request, but we have to loop around 1845 // and check again. Eventually we will get SR_lock without a pending 1846 // external suspend request and will be able to mark ourselves as 1847 // exiting. 1848 } 1849 // no more external suspends are allowed at this point 1850 } else { 1851 // before_exit() has already posted JVMTI THREAD_END events 1852 } 1853 1854 // Notify waiters on thread object. This has to be done after exit() is called 1855 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1856 // group should have the destroyed bit set before waiters are notified). 1857 ensure_join(this); 1858 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1859 1860 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1861 // held by this thread must be released. A detach operation must only 1862 // get here if there are no Java frames on the stack. Therefore, any 1863 // owned monitors at this point MUST be JNI-acquired monitors which are 1864 // pre-inflated and in the monitor cache. 1865 // 1866 // ensure_join() ignores IllegalThreadStateExceptions, and so does this. 1867 if (exit_type == jni_detach && JNIDetachReleasesMonitors) { 1868 assert(!this->has_last_Java_frame(), "detaching with Java frames?"); 1869 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1870 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1871 } 1872 1873 // These things needs to be done while we are still a Java Thread. Make sure that thread 1874 // is in a consistent state, in case GC happens 1875 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1876 1877 if (active_handles() != NULL) { 1878 JNIHandleBlock* block = active_handles(); 1879 set_active_handles(NULL); 1880 JNIHandleBlock::release_block(block); 1881 } 1882 1883 if (free_handle_block() != NULL) { 1884 JNIHandleBlock* block = free_handle_block(); 1885 set_free_handle_block(NULL); 1886 JNIHandleBlock::release_block(block); 1887 } 1888 1889 // These have to be removed while this is still a valid thread. 1890 remove_stack_guard_pages(); 1891 1892 if (UseTLAB) { 1893 tlab().make_parsable(true); // retire TLAB 1894 } 1895 1896 if (JvmtiEnv::environments_might_exist()) { 1897 JvmtiExport::cleanup_thread(this); 1898 } 1899 1900#ifndef SERIALGC 1901 // We must flush G1-related buffers before removing a thread from 1902 // the list of active threads. 1903 if (UseG1GC) { 1904 flush_barrier_queues(); 1905 } 1906#endif 1907 1908 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1909 Threads::remove(this); 1910} 1911 1912#ifndef SERIALGC 1913// Flush G1-related queues. 1914void JavaThread::flush_barrier_queues() { 1915 satb_mark_queue().flush(); 1916 dirty_card_queue().flush(); 1917} 1918 1919void JavaThread::initialize_queues() { 1920 assert(!SafepointSynchronize::is_at_safepoint(), 1921 "we should not be at a safepoint"); 1922 1923 ObjPtrQueue& satb_queue = satb_mark_queue(); 1924 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1925 // The SATB queue should have been constructed with its active 1926 // field set to false. 1927 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1928 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1929 // If we are creating the thread during a marking cycle, we should 1930 // set the active field of the SATB queue to true. 1931 if (satb_queue_set.is_active()) { 1932 satb_queue.set_active(true); 1933 } 1934 1935 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1936 // The dirty card queue should have been constructed with its 1937 // active field set to true. 1938 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1939} 1940#endif // !SERIALGC 1941 1942void JavaThread::cleanup_failed_attach_current_thread() { 1943 if (get_thread_profiler() != NULL) { 1944 get_thread_profiler()->disengage(); 1945 ResourceMark rm; 1946 get_thread_profiler()->print(get_thread_name()); 1947 } 1948 1949 if (active_handles() != NULL) { 1950 JNIHandleBlock* block = active_handles(); 1951 set_active_handles(NULL); 1952 JNIHandleBlock::release_block(block); 1953 } 1954 1955 if (free_handle_block() != NULL) { 1956 JNIHandleBlock* block = free_handle_block(); 1957 set_free_handle_block(NULL); 1958 JNIHandleBlock::release_block(block); 1959 } 1960 1961 // These have to be removed while this is still a valid thread. 1962 remove_stack_guard_pages(); 1963 1964 if (UseTLAB) { 1965 tlab().make_parsable(true); // retire TLAB, if any 1966 } 1967 1968#ifndef SERIALGC 1969 if (UseG1GC) { 1970 flush_barrier_queues(); 1971 } 1972#endif 1973 1974 Threads::remove(this); 1975 delete this; 1976} 1977 1978 1979 1980 1981JavaThread* JavaThread::active() { 1982 Thread* thread = ThreadLocalStorage::thread(); 1983 assert(thread != NULL, "just checking"); 1984 if (thread->is_Java_thread()) { 1985 return (JavaThread*) thread; 1986 } else { 1987 assert(thread->is_VM_thread(), "this must be a vm thread"); 1988 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 1989 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 1990 assert(ret->is_Java_thread(), "must be a Java thread"); 1991 return ret; 1992 } 1993} 1994 1995bool JavaThread::is_lock_owned(address adr) const { 1996 if (Thread::is_lock_owned(adr)) return true; 1997 1998 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 1999 if (chunk->contains(adr)) return true; 2000 } 2001 2002 return false; 2003} 2004 2005 2006void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2007 chunk->set_next(monitor_chunks()); 2008 set_monitor_chunks(chunk); 2009} 2010 2011void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2012 guarantee(monitor_chunks() != NULL, "must be non empty"); 2013 if (monitor_chunks() == chunk) { 2014 set_monitor_chunks(chunk->next()); 2015 } else { 2016 MonitorChunk* prev = monitor_chunks(); 2017 while (prev->next() != chunk) prev = prev->next(); 2018 prev->set_next(chunk->next()); 2019 } 2020} 2021 2022// JVM support. 2023 2024// Note: this function shouldn't block if it's called in 2025// _thread_in_native_trans state (such as from 2026// check_special_condition_for_native_trans()). 2027void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2028 2029 if (has_last_Java_frame() && has_async_condition()) { 2030 // If we are at a polling page safepoint (not a poll return) 2031 // then we must defer async exception because live registers 2032 // will be clobbered by the exception path. Poll return is 2033 // ok because the call we a returning from already collides 2034 // with exception handling registers and so there is no issue. 2035 // (The exception handling path kills call result registers but 2036 // this is ok since the exception kills the result anyway). 2037 2038 if (is_at_poll_safepoint()) { 2039 // if the code we are returning to has deoptimized we must defer 2040 // the exception otherwise live registers get clobbered on the 2041 // exception path before deoptimization is able to retrieve them. 2042 // 2043 RegisterMap map(this, false); 2044 frame caller_fr = last_frame().sender(&map); 2045 assert(caller_fr.is_compiled_frame(), "what?"); 2046 if (caller_fr.is_deoptimized_frame()) { 2047 if (TraceExceptions) { 2048 ResourceMark rm; 2049 tty->print_cr("deferred async exception at compiled safepoint"); 2050 } 2051 return; 2052 } 2053 } 2054 } 2055 2056 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2057 if (condition == _no_async_condition) { 2058 // Conditions have changed since has_special_runtime_exit_condition() 2059 // was called: 2060 // - if we were here only because of an external suspend request, 2061 // then that was taken care of above (or cancelled) so we are done 2062 // - if we were here because of another async request, then it has 2063 // been cleared between the has_special_runtime_exit_condition() 2064 // and now so again we are done 2065 return; 2066 } 2067 2068 // Check for pending async. exception 2069 if (_pending_async_exception != NULL) { 2070 // Only overwrite an already pending exception, if it is not a threadDeath. 2071 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2072 2073 // We cannot call Exceptions::_throw(...) here because we cannot block 2074 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2075 2076 if (TraceExceptions) { 2077 ResourceMark rm; 2078 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", this); 2079 if (has_last_Java_frame() ) { 2080 frame f = last_frame(); 2081 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", f.pc(), f.sp()); 2082 } 2083 tty->print_cr(" of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2084 } 2085 _pending_async_exception = NULL; 2086 clear_has_async_exception(); 2087 } 2088 } 2089 2090 if (check_unsafe_error && 2091 condition == _async_unsafe_access_error && !has_pending_exception()) { 2092 condition = _no_async_condition; // done 2093 switch (thread_state()) { 2094 case _thread_in_vm: 2095 { 2096 JavaThread* THREAD = this; 2097 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2098 } 2099 case _thread_in_native: 2100 { 2101 ThreadInVMfromNative tiv(this); 2102 JavaThread* THREAD = this; 2103 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2104 } 2105 case _thread_in_Java: 2106 { 2107 ThreadInVMfromJava tiv(this); 2108 JavaThread* THREAD = this; 2109 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2110 } 2111 default: 2112 ShouldNotReachHere(); 2113 } 2114 } 2115 2116 assert(condition == _no_async_condition || has_pending_exception() || 2117 (!check_unsafe_error && condition == _async_unsafe_access_error), 2118 "must have handled the async condition, if no exception"); 2119} 2120 2121void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2122 // 2123 // Check for pending external suspend. Internal suspend requests do 2124 // not use handle_special_runtime_exit_condition(). 2125 // If JNIEnv proxies are allowed, don't self-suspend if the target 2126 // thread is not the current thread. In older versions of jdbx, jdbx 2127 // threads could call into the VM with another thread's JNIEnv so we 2128 // can be here operating on behalf of a suspended thread (4432884). 2129 bool do_self_suspend = is_external_suspend_with_lock(); 2130 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2131 // 2132 // Because thread is external suspended the safepoint code will count 2133 // thread as at a safepoint. This can be odd because we can be here 2134 // as _thread_in_Java which would normally transition to _thread_blocked 2135 // at a safepoint. We would like to mark the thread as _thread_blocked 2136 // before calling java_suspend_self like all other callers of it but 2137 // we must then observe proper safepoint protocol. (We can't leave 2138 // _thread_blocked with a safepoint in progress). However we can be 2139 // here as _thread_in_native_trans so we can't use a normal transition 2140 // constructor/destructor pair because they assert on that type of 2141 // transition. We could do something like: 2142 // 2143 // JavaThreadState state = thread_state(); 2144 // set_thread_state(_thread_in_vm); 2145 // { 2146 // ThreadBlockInVM tbivm(this); 2147 // java_suspend_self() 2148 // } 2149 // set_thread_state(_thread_in_vm_trans); 2150 // if (safepoint) block; 2151 // set_thread_state(state); 2152 // 2153 // but that is pretty messy. Instead we just go with the way the 2154 // code has worked before and note that this is the only path to 2155 // java_suspend_self that doesn't put the thread in _thread_blocked 2156 // mode. 2157 2158 frame_anchor()->make_walkable(this); 2159 java_suspend_self(); 2160 2161 // We might be here for reasons in addition to the self-suspend request 2162 // so check for other async requests. 2163 } 2164 2165 if (check_asyncs) { 2166 check_and_handle_async_exceptions(); 2167 } 2168} 2169 2170void JavaThread::send_thread_stop(oop java_throwable) { 2171 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2172 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2173 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2174 2175 // Do not throw asynchronous exceptions against the compiler thread 2176 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2177 if (is_Compiler_thread()) return; 2178 2179 { 2180 // Actually throw the Throwable against the target Thread - however 2181 // only if there is no thread death exception installed already. 2182 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2183 // If the topmost frame is a runtime stub, then we are calling into 2184 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2185 // must deoptimize the caller before continuing, as the compiled exception handler table 2186 // may not be valid 2187 if (has_last_Java_frame()) { 2188 frame f = last_frame(); 2189 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2190 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2191 RegisterMap reg_map(this, UseBiasedLocking); 2192 frame compiled_frame = f.sender(®_map); 2193 if (compiled_frame.can_be_deoptimized()) { 2194 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2195 } 2196 } 2197 } 2198 2199 // Set async. pending exception in thread. 2200 set_pending_async_exception(java_throwable); 2201 2202 if (TraceExceptions) { 2203 ResourceMark rm; 2204 tty->print_cr("Pending Async. exception installed of type: %s", InstanceKlass::cast(_pending_async_exception->klass())->external_name()); 2205 } 2206 // for AbortVMOnException flag 2207 NOT_PRODUCT(Exceptions::debug_check_abort(InstanceKlass::cast(_pending_async_exception->klass())->external_name())); 2208 } 2209 } 2210 2211 2212 // Interrupt thread so it will wake up from a potential wait() 2213 Thread::interrupt(this); 2214} 2215 2216// External suspension mechanism. 2217// 2218// Tell the VM to suspend a thread when ever it knows that it does not hold on 2219// to any VM_locks and it is at a transition 2220// Self-suspension will happen on the transition out of the vm. 2221// Catch "this" coming in from JNIEnv pointers when the thread has been freed 2222// 2223// Guarantees on return: 2224// + Target thread will not execute any new bytecode (that's why we need to 2225// force a safepoint) 2226// + Target thread will not enter any new monitors 2227// 2228void JavaThread::java_suspend() { 2229 { MutexLocker mu(Threads_lock); 2230 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2231 return; 2232 } 2233 } 2234 2235 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2236 if (!is_external_suspend()) { 2237 // a racing resume has cancelled us; bail out now 2238 return; 2239 } 2240 2241 // suspend is done 2242 uint32_t debug_bits = 0; 2243 // Warning: is_ext_suspend_completed() may temporarily drop the 2244 // SR_lock to allow the thread to reach a stable thread state if 2245 // it is currently in a transient thread state. 2246 if (is_ext_suspend_completed(false /* !called_by_wait */, 2247 SuspendRetryDelay, &debug_bits) ) { 2248 return; 2249 } 2250 } 2251 2252 VM_ForceSafepoint vm_suspend; 2253 VMThread::execute(&vm_suspend); 2254} 2255 2256// Part II of external suspension. 2257// A JavaThread self suspends when it detects a pending external suspend 2258// request. This is usually on transitions. It is also done in places 2259// where continuing to the next transition would surprise the caller, 2260// e.g., monitor entry. 2261// 2262// Returns the number of times that the thread self-suspended. 2263// 2264// Note: DO NOT call java_suspend_self() when you just want to block current 2265// thread. java_suspend_self() is the second stage of cooperative 2266// suspension for external suspend requests and should only be used 2267// to complete an external suspend request. 2268// 2269int JavaThread::java_suspend_self() { 2270 int ret = 0; 2271 2272 // we are in the process of exiting so don't suspend 2273 if (is_exiting()) { 2274 clear_external_suspend(); 2275 return ret; 2276 } 2277 2278 assert(_anchor.walkable() || 2279 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2280 "must have walkable stack"); 2281 2282 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2283 2284 assert(!this->is_ext_suspended(), 2285 "a thread trying to self-suspend should not already be suspended"); 2286 2287 if (this->is_suspend_equivalent()) { 2288 // If we are self-suspending as a result of the lifting of a 2289 // suspend equivalent condition, then the suspend_equivalent 2290 // flag is not cleared until we set the ext_suspended flag so 2291 // that wait_for_ext_suspend_completion() returns consistent 2292 // results. 2293 this->clear_suspend_equivalent(); 2294 } 2295 2296 // A racing resume may have cancelled us before we grabbed SR_lock 2297 // above. Or another external suspend request could be waiting for us 2298 // by the time we return from SR_lock()->wait(). The thread 2299 // that requested the suspension may already be trying to walk our 2300 // stack and if we return now, we can change the stack out from under 2301 // it. This would be a "bad thing (TM)" and cause the stack walker 2302 // to crash. We stay self-suspended until there are no more pending 2303 // external suspend requests. 2304 while (is_external_suspend()) { 2305 ret++; 2306 this->set_ext_suspended(); 2307 2308 // _ext_suspended flag is cleared by java_resume() 2309 while (is_ext_suspended()) { 2310 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2311 } 2312 } 2313 2314 return ret; 2315} 2316 2317#ifdef ASSERT 2318// verify the JavaThread has not yet been published in the Threads::list, and 2319// hence doesn't need protection from concurrent access at this stage 2320void JavaThread::verify_not_published() { 2321 if (!Threads_lock->owned_by_self()) { 2322 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2323 assert( !Threads::includes(this), 2324 "java thread shouldn't have been published yet!"); 2325 } 2326 else { 2327 assert( !Threads::includes(this), 2328 "java thread shouldn't have been published yet!"); 2329 } 2330} 2331#endif 2332 2333// Slow path when the native==>VM/Java barriers detect a safepoint is in 2334// progress or when _suspend_flags is non-zero. 2335// Current thread needs to self-suspend if there is a suspend request and/or 2336// block if a safepoint is in progress. 2337// Async exception ISN'T checked. 2338// Note only the ThreadInVMfromNative transition can call this function 2339// directly and when thread state is _thread_in_native_trans 2340void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2341 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2342 2343 JavaThread *curJT = JavaThread::current(); 2344 bool do_self_suspend = thread->is_external_suspend(); 2345 2346 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2347 2348 // If JNIEnv proxies are allowed, don't self-suspend if the target 2349 // thread is not the current thread. In older versions of jdbx, jdbx 2350 // threads could call into the VM with another thread's JNIEnv so we 2351 // can be here operating on behalf of a suspended thread (4432884). 2352 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2353 JavaThreadState state = thread->thread_state(); 2354 2355 // We mark this thread_blocked state as a suspend-equivalent so 2356 // that a caller to is_ext_suspend_completed() won't be confused. 2357 // The suspend-equivalent state is cleared by java_suspend_self(). 2358 thread->set_suspend_equivalent(); 2359 2360 // If the safepoint code sees the _thread_in_native_trans state, it will 2361 // wait until the thread changes to other thread state. There is no 2362 // guarantee on how soon we can obtain the SR_lock and complete the 2363 // self-suspend request. It would be a bad idea to let safepoint wait for 2364 // too long. Temporarily change the state to _thread_blocked to 2365 // let the VM thread know that this thread is ready for GC. The problem 2366 // of changing thread state is that safepoint could happen just after 2367 // java_suspend_self() returns after being resumed, and VM thread will 2368 // see the _thread_blocked state. We must check for safepoint 2369 // after restoring the state and make sure we won't leave while a safepoint 2370 // is in progress. 2371 thread->set_thread_state(_thread_blocked); 2372 thread->java_suspend_self(); 2373 thread->set_thread_state(state); 2374 // Make sure new state is seen by VM thread 2375 if (os::is_MP()) { 2376 if (UseMembar) { 2377 // Force a fence between the write above and read below 2378 OrderAccess::fence(); 2379 } else { 2380 // Must use this rather than serialization page in particular on Windows 2381 InterfaceSupport::serialize_memory(thread); 2382 } 2383 } 2384 } 2385 2386 if (SafepointSynchronize::do_call_back()) { 2387 // If we are safepointing, then block the caller which may not be 2388 // the same as the target thread (see above). 2389 SafepointSynchronize::block(curJT); 2390 } 2391 2392 if (thread->is_deopt_suspend()) { 2393 thread->clear_deopt_suspend(); 2394 RegisterMap map(thread, false); 2395 frame f = thread->last_frame(); 2396 while ( f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2397 f = f.sender(&map); 2398 } 2399 if (f.id() == thread->must_deopt_id()) { 2400 thread->clear_must_deopt_id(); 2401 f.deoptimize(thread); 2402 } else { 2403 fatal("missed deoptimization!"); 2404 } 2405 } 2406} 2407 2408// Slow path when the native==>VM/Java barriers detect a safepoint is in 2409// progress or when _suspend_flags is non-zero. 2410// Current thread needs to self-suspend if there is a suspend request and/or 2411// block if a safepoint is in progress. 2412// Also check for pending async exception (not including unsafe access error). 2413// Note only the native==>VM/Java barriers can call this function and when 2414// thread state is _thread_in_native_trans. 2415void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2416 check_safepoint_and_suspend_for_native_trans(thread); 2417 2418 if (thread->has_async_exception()) { 2419 // We are in _thread_in_native_trans state, don't handle unsafe 2420 // access error since that may block. 2421 thread->check_and_handle_async_exceptions(false); 2422 } 2423} 2424 2425// This is a variant of the normal 2426// check_special_condition_for_native_trans with slightly different 2427// semantics for use by critical native wrappers. It does all the 2428// normal checks but also performs the transition back into 2429// thread_in_Java state. This is required so that critical natives 2430// can potentially block and perform a GC if they are the last thread 2431// exiting the GC_locker. 2432void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2433 check_special_condition_for_native_trans(thread); 2434 2435 // Finish the transition 2436 thread->set_thread_state(_thread_in_Java); 2437 2438 if (thread->do_critical_native_unlock()) { 2439 ThreadInVMfromJavaNoAsyncException tiv(thread); 2440 GC_locker::unlock_critical(thread); 2441 thread->clear_critical_native_unlock(); 2442 } 2443} 2444 2445// We need to guarantee the Threads_lock here, since resumes are not 2446// allowed during safepoint synchronization 2447// Can only resume from an external suspension 2448void JavaThread::java_resume() { 2449 assert_locked_or_safepoint(Threads_lock); 2450 2451 // Sanity check: thread is gone, has started exiting or the thread 2452 // was not externally suspended. 2453 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2454 return; 2455 } 2456 2457 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2458 2459 clear_external_suspend(); 2460 2461 if (is_ext_suspended()) { 2462 clear_ext_suspended(); 2463 SR_lock()->notify_all(); 2464 } 2465} 2466 2467void JavaThread::create_stack_guard_pages() { 2468 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2469 address low_addr = stack_base() - stack_size(); 2470 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2471 2472 int allocate = os::allocate_stack_guard_pages(); 2473 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2474 2475 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2476 warning("Attempt to allocate stack guard pages failed."); 2477 return; 2478 } 2479 2480 if (os::guard_memory((char *) low_addr, len)) { 2481 _stack_guard_state = stack_guard_enabled; 2482 } else { 2483 warning("Attempt to protect stack guard pages failed."); 2484 if (os::uncommit_memory((char *) low_addr, len)) { 2485 warning("Attempt to deallocate stack guard pages failed."); 2486 } 2487 } 2488} 2489 2490void JavaThread::remove_stack_guard_pages() { 2491 assert(Thread::current() == this, "from different thread"); 2492 if (_stack_guard_state == stack_guard_unused) return; 2493 address low_addr = stack_base() - stack_size(); 2494 size_t len = (StackYellowPages + StackRedPages) * os::vm_page_size(); 2495 2496 if (os::allocate_stack_guard_pages()) { 2497 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2498 _stack_guard_state = stack_guard_unused; 2499 } else { 2500 warning("Attempt to deallocate stack guard pages failed."); 2501 } 2502 } else { 2503 if (_stack_guard_state == stack_guard_unused) return; 2504 if (os::unguard_memory((char *) low_addr, len)) { 2505 _stack_guard_state = stack_guard_unused; 2506 } else { 2507 warning("Attempt to unprotect stack guard pages failed."); 2508 } 2509 } 2510} 2511 2512void JavaThread::enable_stack_yellow_zone() { 2513 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2514 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2515 2516 // The base notation is from the stacks point of view, growing downward. 2517 // We need to adjust it to work correctly with guard_memory() 2518 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2519 2520 guarantee(base < stack_base(),"Error calculating stack yellow zone"); 2521 guarantee(base < os::current_stack_pointer(),"Error calculating stack yellow zone"); 2522 2523 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2524 _stack_guard_state = stack_guard_enabled; 2525 } else { 2526 warning("Attempt to guard stack yellow zone failed."); 2527 } 2528 enable_register_stack_guard(); 2529} 2530 2531void JavaThread::disable_stack_yellow_zone() { 2532 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2533 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2534 2535 // Simply return if called for a thread that does not use guard pages. 2536 if (_stack_guard_state == stack_guard_unused) return; 2537 2538 // The base notation is from the stacks point of view, growing downward. 2539 // We need to adjust it to work correctly with guard_memory() 2540 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2541 2542 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2543 _stack_guard_state = stack_guard_yellow_disabled; 2544 } else { 2545 warning("Attempt to unguard stack yellow zone failed."); 2546 } 2547 disable_register_stack_guard(); 2548} 2549 2550void JavaThread::enable_stack_red_zone() { 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 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2554 address base = stack_red_zone_base() - stack_red_zone_size(); 2555 2556 guarantee(base < stack_base(),"Error calculating stack red zone"); 2557 guarantee(base < os::current_stack_pointer(),"Error calculating stack red zone"); 2558 2559 if(!os::guard_memory((char *) base, stack_red_zone_size())) { 2560 warning("Attempt to guard stack red zone failed."); 2561 } 2562} 2563 2564void JavaThread::disable_stack_red_zone() { 2565 // The base notation is from the stacks point of view, growing downward. 2566 // We need to adjust it to work correctly with guard_memory() 2567 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2568 address base = stack_red_zone_base() - stack_red_zone_size(); 2569 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2570 warning("Attempt to unguard stack red zone failed."); 2571 } 2572} 2573 2574void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2575 // ignore is there is no stack 2576 if (!has_last_Java_frame()) return; 2577 // traverse the stack frames. Starts from top frame. 2578 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2579 frame* fr = fst.current(); 2580 f(fr, fst.register_map()); 2581 } 2582} 2583 2584 2585#ifndef PRODUCT 2586// Deoptimization 2587// Function for testing deoptimization 2588void JavaThread::deoptimize() { 2589 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2590 StackFrameStream fst(this, UseBiasedLocking); 2591 bool deopt = false; // Dump stack only if a deopt actually happens. 2592 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2593 // Iterate over all frames in the thread and deoptimize 2594 for(; !fst.is_done(); fst.next()) { 2595 if(fst.current()->can_be_deoptimized()) { 2596 2597 if (only_at) { 2598 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2599 // consists of comma or carriage return separated numbers so 2600 // search for the current bci in that string. 2601 address pc = fst.current()->pc(); 2602 nmethod* nm = (nmethod*) fst.current()->cb(); 2603 ScopeDesc* sd = nm->scope_desc_at( pc); 2604 char buffer[8]; 2605 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2606 size_t len = strlen(buffer); 2607 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2608 while (found != NULL) { 2609 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2610 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2611 // Check that the bci found is bracketed by terminators. 2612 break; 2613 } 2614 found = strstr(found + 1, buffer); 2615 } 2616 if (!found) { 2617 continue; 2618 } 2619 } 2620 2621 if (DebugDeoptimization && !deopt) { 2622 deopt = true; // One-time only print before deopt 2623 tty->print_cr("[BEFORE Deoptimization]"); 2624 trace_frames(); 2625 trace_stack(); 2626 } 2627 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2628 } 2629 } 2630 2631 if (DebugDeoptimization && deopt) { 2632 tty->print_cr("[AFTER Deoptimization]"); 2633 trace_frames(); 2634 } 2635} 2636 2637 2638// Make zombies 2639void JavaThread::make_zombies() { 2640 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2641 if (fst.current()->can_be_deoptimized()) { 2642 // it is a Java nmethod 2643 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2644 nm->make_not_entrant(); 2645 } 2646 } 2647} 2648#endif // PRODUCT 2649 2650 2651void JavaThread::deoptimized_wrt_marked_nmethods() { 2652 if (!has_last_Java_frame()) return; 2653 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2654 StackFrameStream fst(this, UseBiasedLocking); 2655 for(; !fst.is_done(); fst.next()) { 2656 if (fst.current()->should_be_deoptimized()) { 2657 if (LogCompilation && xtty != NULL) { 2658 nmethod* nm = fst.current()->cb()->as_nmethod_or_null(); 2659 xtty->elem("deoptimized thread='" UINTX_FORMAT "' compile_id='%d'", 2660 this->name(), nm != NULL ? nm->compile_id() : -1); 2661 } 2662 2663 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2664 } 2665 } 2666} 2667 2668 2669// GC support 2670static void frame_gc_epilogue(frame* f, const RegisterMap* map) { f->gc_epilogue(); } 2671 2672void JavaThread::gc_epilogue() { 2673 frames_do(frame_gc_epilogue); 2674} 2675 2676 2677static void frame_gc_prologue(frame* f, const RegisterMap* map) { f->gc_prologue(); } 2678 2679void JavaThread::gc_prologue() { 2680 frames_do(frame_gc_prologue); 2681} 2682 2683// If the caller is a NamedThread, then remember, in the current scope, 2684// the given JavaThread in its _processed_thread field. 2685class RememberProcessedThread: public StackObj { 2686 NamedThread* _cur_thr; 2687public: 2688 RememberProcessedThread(JavaThread* jthr) { 2689 Thread* thread = Thread::current(); 2690 if (thread->is_Named_thread()) { 2691 _cur_thr = (NamedThread *)thread; 2692 _cur_thr->set_processed_thread(jthr); 2693 } else { 2694 _cur_thr = NULL; 2695 } 2696 } 2697 2698 ~RememberProcessedThread() { 2699 if (_cur_thr) { 2700 _cur_thr->set_processed_thread(NULL); 2701 } 2702 } 2703}; 2704 2705void JavaThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 2706 // Verify that the deferred card marks have been flushed. 2707 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2708 2709 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2710 // since there may be more than one thread using each ThreadProfiler. 2711 2712 // Traverse the GCHandles 2713 Thread::oops_do(f, cld_f, cf); 2714 2715 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2716 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2717 2718 if (has_last_Java_frame()) { 2719 // Record JavaThread to GC thread 2720 RememberProcessedThread rpt(this); 2721 2722 // Traverse the privileged stack 2723 if (_privileged_stack_top != NULL) { 2724 _privileged_stack_top->oops_do(f); 2725 } 2726 2727 // traverse the registered growable array 2728 if (_array_for_gc != NULL) { 2729 for (int index = 0; index < _array_for_gc->length(); index++) { 2730 f->do_oop(_array_for_gc->adr_at(index)); 2731 } 2732 } 2733 2734 // Traverse the monitor chunks 2735 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2736 chunk->oops_do(f); 2737 } 2738 2739 // Traverse the execution stack 2740 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2741 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2742 } 2743 } 2744 2745 // callee_target is never live across a gc point so NULL it here should 2746 // it still contain a methdOop. 2747 2748 set_callee_target(NULL); 2749 2750 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2751 // If we have deferred set_locals there might be oops waiting to be 2752 // written 2753 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2754 if (list != NULL) { 2755 for (int i = 0; i < list->length(); i++) { 2756 list->at(i)->oops_do(f); 2757 } 2758 } 2759 2760 // Traverse instance variables at the end since the GC may be moving things 2761 // around using this function 2762 f->do_oop((oop*) &_threadObj); 2763 f->do_oop((oop*) &_vm_result); 2764 f->do_oop((oop*) &_exception_oop); 2765 f->do_oop((oop*) &_pending_async_exception); 2766 2767 if (jvmti_thread_state() != NULL) { 2768 jvmti_thread_state()->oops_do(f); 2769 } 2770} 2771 2772void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2773 Thread::nmethods_do(cf); // (super method is a no-op) 2774 2775 assert( (!has_last_Java_frame() && java_call_counter() == 0) || 2776 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2777 2778 if (has_last_Java_frame()) { 2779 // Traverse the execution stack 2780 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2781 fst.current()->nmethods_do(cf); 2782 } 2783 } 2784} 2785 2786void JavaThread::metadata_do(void f(Metadata*)) { 2787 Thread::metadata_do(f); 2788 if (has_last_Java_frame()) { 2789 // Traverse the execution stack to call f() on the methods in the stack 2790 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2791 fst.current()->metadata_do(f); 2792 } 2793 } else if (is_Compiler_thread()) { 2794 // need to walk ciMetadata in current compile tasks to keep alive. 2795 CompilerThread* ct = (CompilerThread*)this; 2796 if (ct->env() != NULL) { 2797 ct->env()->metadata_do(f); 2798 } 2799 } 2800} 2801 2802// Printing 2803const char* _get_thread_state_name(JavaThreadState _thread_state) { 2804 switch (_thread_state) { 2805 case _thread_uninitialized: return "_thread_uninitialized"; 2806 case _thread_new: return "_thread_new"; 2807 case _thread_new_trans: return "_thread_new_trans"; 2808 case _thread_in_native: return "_thread_in_native"; 2809 case _thread_in_native_trans: return "_thread_in_native_trans"; 2810 case _thread_in_vm: return "_thread_in_vm"; 2811 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2812 case _thread_in_Java: return "_thread_in_Java"; 2813 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2814 case _thread_blocked: return "_thread_blocked"; 2815 case _thread_blocked_trans: return "_thread_blocked_trans"; 2816 default: return "unknown thread state"; 2817 } 2818} 2819 2820#ifndef PRODUCT 2821void JavaThread::print_thread_state_on(outputStream *st) const { 2822 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2823}; 2824void JavaThread::print_thread_state() const { 2825 print_thread_state_on(tty); 2826}; 2827#endif // PRODUCT 2828 2829// Called by Threads::print() for VM_PrintThreads operation 2830void JavaThread::print_on(outputStream *st) const { 2831 st->print("\"%s\" ", get_thread_name()); 2832 oop thread_oop = threadObj(); 2833 if (thread_oop != NULL) { 2834 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2835 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2836 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2837 } 2838 Thread::print_on(st); 2839 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2840 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2841 if (thread_oop != NULL && JDK_Version::is_gte_jdk15x_version()) { 2842 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2843 } 2844#ifndef PRODUCT 2845 print_thread_state_on(st); 2846 _safepoint_state->print_on(st); 2847#endif // PRODUCT 2848} 2849 2850// Called by fatal error handler. The difference between this and 2851// JavaThread::print() is that we can't grab lock or allocate memory. 2852void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2853 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2854 oop thread_obj = threadObj(); 2855 if (thread_obj != NULL) { 2856 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2857 } 2858 st->print(" ["); 2859 st->print("%s", _get_thread_state_name(_thread_state)); 2860 if (osthread()) { 2861 st->print(", id=%d", osthread()->thread_id()); 2862 } 2863 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2864 _stack_base - _stack_size, _stack_base); 2865 st->print("]"); 2866 return; 2867} 2868 2869// Verification 2870 2871static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2872 2873void JavaThread::verify() { 2874 // Verify oops in the thread. 2875 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2876 2877 // Verify the stack frames. 2878 frames_do(frame_verify); 2879} 2880 2881// CR 6300358 (sub-CR 2137150) 2882// Most callers of this method assume that it can't return NULL but a 2883// thread may not have a name whilst it is in the process of attaching to 2884// the VM - see CR 6412693, and there are places where a JavaThread can be 2885// seen prior to having it's threadObj set (eg JNI attaching threads and 2886// if vm exit occurs during initialization). These cases can all be accounted 2887// for such that this method never returns NULL. 2888const char* JavaThread::get_thread_name() const { 2889#ifdef ASSERT 2890 // early safepoints can hit while current thread does not yet have TLS 2891 if (!SafepointSynchronize::is_at_safepoint()) { 2892 Thread *cur = Thread::current(); 2893 if (!(cur->is_Java_thread() && cur == this)) { 2894 // Current JavaThreads are allowed to get their own name without 2895 // the Threads_lock. 2896 assert_locked_or_safepoint(Threads_lock); 2897 } 2898 } 2899#endif // ASSERT 2900 return get_thread_name_string(); 2901} 2902 2903// Returns a non-NULL representation of this thread's name, or a suitable 2904// descriptive string if there is no set name 2905const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2906 const char* name_str; 2907 oop thread_obj = threadObj(); 2908 if (thread_obj != NULL) { 2909 typeArrayOop name = java_lang_Thread::name(thread_obj); 2910 if (name != NULL) { 2911 if (buf == NULL) { 2912 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2913 } 2914 else { 2915 name_str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length(), buf, buflen); 2916 } 2917 } 2918 else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2919 name_str = "<no-name - thread is attaching>"; 2920 } 2921 else { 2922 name_str = Thread::name(); 2923 } 2924 } 2925 else { 2926 name_str = Thread::name(); 2927 } 2928 assert(name_str != NULL, "unexpected NULL thread name"); 2929 return name_str; 2930} 2931 2932 2933const char* JavaThread::get_threadgroup_name() const { 2934 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2935 oop thread_obj = threadObj(); 2936 if (thread_obj != NULL) { 2937 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2938 if (thread_group != NULL) { 2939 typeArrayOop name = java_lang_ThreadGroup::name(thread_group); 2940 // ThreadGroup.name can be null 2941 if (name != NULL) { 2942 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2943 return str; 2944 } 2945 } 2946 } 2947 return NULL; 2948} 2949 2950const char* JavaThread::get_parent_name() const { 2951 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2952 oop thread_obj = threadObj(); 2953 if (thread_obj != NULL) { 2954 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2955 if (thread_group != NULL) { 2956 oop parent = java_lang_ThreadGroup::parent(thread_group); 2957 if (parent != NULL) { 2958 typeArrayOop name = java_lang_ThreadGroup::name(parent); 2959 // ThreadGroup.name can be null 2960 if (name != NULL) { 2961 const char* str = UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length()); 2962 return str; 2963 } 2964 } 2965 } 2966 } 2967 return NULL; 2968} 2969 2970ThreadPriority JavaThread::java_priority() const { 2971 oop thr_oop = threadObj(); 2972 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2973 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 2974 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 2975 return priority; 2976} 2977 2978void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 2979 2980 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 2981 // Link Java Thread object <-> C++ Thread 2982 2983 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 2984 // and put it into a new Handle. The Handle "thread_oop" can then 2985 // be used to pass the C++ thread object to other methods. 2986 2987 // Set the Java level thread object (jthread) field of the 2988 // new thread (a JavaThread *) to C++ thread object using the 2989 // "thread_oop" handle. 2990 2991 // Set the thread field (a JavaThread *) of the 2992 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 2993 2994 Handle thread_oop(Thread::current(), 2995 JNIHandles::resolve_non_null(jni_thread)); 2996 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 2997 "must be initialized"); 2998 set_threadObj(thread_oop()); 2999 java_lang_Thread::set_thread(thread_oop(), this); 3000 3001 if (prio == NoPriority) { 3002 prio = java_lang_Thread::priority(thread_oop()); 3003 assert(prio != NoPriority, "A valid priority should be present"); 3004 } 3005 3006 // Push the Java priority down to the native thread; needs Threads_lock 3007 Thread::set_priority(this, prio); 3008 3009 // Add the new thread to the Threads list and set it in motion. 3010 // We must have threads lock in order to call Threads::add. 3011 // It is crucial that we do not block before the thread is 3012 // added to the Threads list for if a GC happens, then the java_thread oop 3013 // will not be visited by GC. 3014 Threads::add(this); 3015} 3016 3017oop JavaThread::current_park_blocker() { 3018 // Support for JSR-166 locks 3019 oop thread_oop = threadObj(); 3020 if (thread_oop != NULL && 3021 JDK_Version::current().supports_thread_park_blocker()) { 3022 return java_lang_Thread::park_blocker(thread_oop); 3023 } 3024 return NULL; 3025} 3026 3027 3028void JavaThread::print_stack_on(outputStream* st) { 3029 if (!has_last_Java_frame()) return; 3030 ResourceMark rm; 3031 HandleMark hm; 3032 3033 RegisterMap reg_map(this); 3034 vframe* start_vf = last_java_vframe(®_map); 3035 int count = 0; 3036 for (vframe* f = start_vf; f; f = f->sender() ) { 3037 if (f->is_java_frame()) { 3038 javaVFrame* jvf = javaVFrame::cast(f); 3039 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3040 3041 // Print out lock information 3042 if (JavaMonitorsInStackTrace) { 3043 jvf->print_lock_info_on(st, count); 3044 } 3045 } else { 3046 // Ignore non-Java frames 3047 } 3048 3049 // Bail-out case for too deep stacks 3050 count++; 3051 if (MaxJavaStackTraceDepth == count) return; 3052 } 3053} 3054 3055 3056// JVMTI PopFrame support 3057void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3058 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3059 if (in_bytes(size_in_bytes) != 0) { 3060 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3061 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3062 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3063 } 3064} 3065 3066void* JavaThread::popframe_preserved_args() { 3067 return _popframe_preserved_args; 3068} 3069 3070ByteSize JavaThread::popframe_preserved_args_size() { 3071 return in_ByteSize(_popframe_preserved_args_size); 3072} 3073 3074WordSize JavaThread::popframe_preserved_args_size_in_words() { 3075 int sz = in_bytes(popframe_preserved_args_size()); 3076 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3077 return in_WordSize(sz / wordSize); 3078} 3079 3080void JavaThread::popframe_free_preserved_args() { 3081 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3082 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args, mtThread); 3083 _popframe_preserved_args = NULL; 3084 _popframe_preserved_args_size = 0; 3085} 3086 3087#ifndef PRODUCT 3088 3089void JavaThread::trace_frames() { 3090 tty->print_cr("[Describe stack]"); 3091 int frame_no = 1; 3092 for(StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3093 tty->print(" %d. ", frame_no++); 3094 fst.current()->print_value_on(tty,this); 3095 tty->cr(); 3096 } 3097} 3098 3099class PrintAndVerifyOopClosure: public OopClosure { 3100 protected: 3101 template <class T> inline void do_oop_work(T* p) { 3102 oop obj = oopDesc::load_decode_heap_oop(p); 3103 if (obj == NULL) return; 3104 tty->print(INTPTR_FORMAT ": ", p); 3105 if (obj->is_oop_or_null()) { 3106 if (obj->is_objArray()) { 3107 tty->print_cr("valid objArray: " INTPTR_FORMAT, (oopDesc*) obj); 3108 } else { 3109 obj->print(); 3110 } 3111 } else { 3112 tty->print_cr("invalid oop: " INTPTR_FORMAT, (oopDesc*) obj); 3113 } 3114 tty->cr(); 3115 } 3116 public: 3117 virtual void do_oop(oop* p) { do_oop_work(p); } 3118 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3119}; 3120 3121 3122static void oops_print(frame* f, const RegisterMap *map) { 3123 PrintAndVerifyOopClosure print; 3124 f->print_value(); 3125 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3126} 3127 3128// Print our all the locations that contain oops and whether they are 3129// valid or not. This useful when trying to find the oldest frame 3130// where an oop has gone bad since the frame walk is from youngest to 3131// oldest. 3132void JavaThread::trace_oops() { 3133 tty->print_cr("[Trace oops]"); 3134 frames_do(oops_print); 3135} 3136 3137 3138#ifdef ASSERT 3139// Print or validate the layout of stack frames 3140void JavaThread::print_frame_layout(int depth, bool validate_only) { 3141 ResourceMark rm; 3142 PRESERVE_EXCEPTION_MARK; 3143 FrameValues values; 3144 int frame_no = 0; 3145 for(StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3146 fst.current()->describe(values, ++frame_no); 3147 if (depth == frame_no) break; 3148 } 3149 if (validate_only) { 3150 values.validate(); 3151 } else { 3152 tty->print_cr("[Describe stack layout]"); 3153 values.print(this); 3154 } 3155} 3156#endif 3157 3158void JavaThread::trace_stack_from(vframe* start_vf) { 3159 ResourceMark rm; 3160 int vframe_no = 1; 3161 for (vframe* f = start_vf; f; f = f->sender() ) { 3162 if (f->is_java_frame()) { 3163 javaVFrame::cast(f)->print_activation(vframe_no++); 3164 } else { 3165 f->print(); 3166 } 3167 if (vframe_no > StackPrintLimit) { 3168 tty->print_cr("...<more frames>..."); 3169 return; 3170 } 3171 } 3172} 3173 3174 3175void JavaThread::trace_stack() { 3176 if (!has_last_Java_frame()) return; 3177 ResourceMark rm; 3178 HandleMark hm; 3179 RegisterMap reg_map(this); 3180 trace_stack_from(last_java_vframe(®_map)); 3181} 3182 3183 3184#endif // PRODUCT 3185 3186 3187javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3188 assert(reg_map != NULL, "a map must be given"); 3189 frame f = last_frame(); 3190 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender() ) { 3191 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3192 } 3193 return NULL; 3194} 3195 3196 3197Klass* JavaThread::security_get_caller_class(int depth) { 3198 vframeStream vfst(this); 3199 vfst.security_get_caller_frame(depth); 3200 if (!vfst.at_end()) { 3201 return vfst.method()->method_holder(); 3202 } 3203 return NULL; 3204} 3205 3206static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3207 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3208 CompileBroker::compiler_thread_loop(); 3209} 3210 3211// Create a CompilerThread 3212CompilerThread::CompilerThread(CompileQueue* queue, CompilerCounters* counters) 3213: JavaThread(&compiler_thread_entry) { 3214 _env = NULL; 3215 _log = NULL; 3216 _task = NULL; 3217 _queue = queue; 3218 _counters = counters; 3219 _buffer_blob = NULL; 3220 _scanned_nmethod = NULL; 3221 3222#ifndef PRODUCT 3223 _ideal_graph_printer = NULL; 3224#endif 3225} 3226 3227void CompilerThread::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 3228 JavaThread::oops_do(f, cld_f, cf); 3229 if (_scanned_nmethod != NULL && cf != NULL) { 3230 // Safepoints can occur when the sweeper is scanning an nmethod so 3231 // process it here to make sure it isn't unloaded in the middle of 3232 // a scan. 3233 cf->do_code_blob(_scanned_nmethod); 3234 } 3235} 3236 3237// ======= Threads ======== 3238 3239// The Threads class links together all active threads, and provides 3240// operations over all threads. It is protected by its own Mutex 3241// lock, which is also used in other contexts to protect thread 3242// operations from having the thread being operated on from exiting 3243// and going away unexpectedly (e.g., safepoint synchronization) 3244 3245JavaThread* Threads::_thread_list = NULL; 3246int Threads::_number_of_threads = 0; 3247int Threads::_number_of_non_daemon_threads = 0; 3248int Threads::_return_code = 0; 3249size_t JavaThread::_stack_size_at_create = 0; 3250#ifdef ASSERT 3251bool Threads::_vm_complete = false; 3252#endif 3253 3254// All JavaThreads 3255#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3256 3257void os_stream(); 3258 3259// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3260void Threads::threads_do(ThreadClosure* tc) { 3261 assert_locked_or_safepoint(Threads_lock); 3262 // ALL_JAVA_THREADS iterates through all JavaThreads 3263 ALL_JAVA_THREADS(p) { 3264 tc->do_thread(p); 3265 } 3266 // Someday we could have a table or list of all non-JavaThreads. 3267 // For now, just manually iterate through them. 3268 tc->do_thread(VMThread::vm_thread()); 3269 Universe::heap()->gc_threads_do(tc); 3270 WatcherThread *wt = WatcherThread::watcher_thread(); 3271 // Strictly speaking, the following NULL check isn't sufficient to make sure 3272 // the data for WatcherThread is still valid upon being examined. However, 3273 // considering that WatchThread terminates when the VM is on the way to 3274 // exit at safepoint, the chance of the above is extremely small. The right 3275 // way to prevent termination of WatcherThread would be to acquire 3276 // Terminator_lock, but we can't do that without violating the lock rank 3277 // checking in some cases. 3278 if (wt != NULL) 3279 tc->do_thread(wt); 3280 3281 // If CompilerThreads ever become non-JavaThreads, add them here 3282} 3283 3284jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3285 3286 extern void JDK_Version_init(); 3287 3288 // Check version 3289 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3290 3291 // Initialize the output stream module 3292 ostream_init(); 3293 3294 // Process java launcher properties. 3295 Arguments::process_sun_java_launcher_properties(args); 3296 3297 // Initialize the os module before using TLS 3298 os::init(); 3299 3300 // Initialize system properties. 3301 Arguments::init_system_properties(); 3302 3303 // So that JDK version can be used as a discrimintor when parsing arguments 3304 JDK_Version_init(); 3305 3306 // Update/Initialize System properties after JDK version number is known 3307 Arguments::init_version_specific_system_properties(); 3308 3309 // Parse arguments 3310 jint parse_result = Arguments::parse(args); 3311 if (parse_result != JNI_OK) return parse_result; 3312 3313 if (PauseAtStartup) { 3314 os::pause(); 3315 } 3316 3317#ifndef USDT2 3318 HS_DTRACE_PROBE(hotspot, vm__init__begin); 3319#else /* USDT2 */ 3320 HOTSPOT_VM_INIT_BEGIN(); 3321#endif /* USDT2 */ 3322 3323 // Record VM creation timing statistics 3324 TraceVmCreationTime create_vm_timer; 3325 create_vm_timer.start(); 3326 3327 // Timing (must come after argument parsing) 3328 TraceTime timer("Create VM", TraceStartupTime); 3329 3330 // Initialize the os module after parsing the args 3331 jint os_init_2_result = os::init_2(); 3332 if (os_init_2_result != JNI_OK) return os_init_2_result; 3333 3334 jint adjust_after_os_result = Arguments::adjust_after_os(); 3335 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3336 3337 // intialize TLS 3338 ThreadLocalStorage::init(); 3339 3340 // Bootstrap native memory tracking, so it can start recording memory 3341 // activities before worker thread is started. This is the first phase 3342 // of bootstrapping, VM is currently running in single-thread mode. 3343 MemTracker::bootstrap_single_thread(); 3344 3345 // Initialize output stream logging 3346 ostream_init_log(); 3347 3348 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3349 // Must be before create_vm_init_agents() 3350 if (Arguments::init_libraries_at_startup()) { 3351 convert_vm_init_libraries_to_agents(); 3352 } 3353 3354 // Launch -agentlib/-agentpath and converted -Xrun agents 3355 if (Arguments::init_agents_at_startup()) { 3356 create_vm_init_agents(); 3357 } 3358 3359 // Initialize Threads state 3360 _thread_list = NULL; 3361 _number_of_threads = 0; 3362 _number_of_non_daemon_threads = 0; 3363 3364 // Initialize global data structures and create system classes in heap 3365 vm_init_globals(); 3366 3367 // Attach the main thread to this os thread 3368 JavaThread* main_thread = new JavaThread(); 3369 main_thread->set_thread_state(_thread_in_vm); 3370 // must do this before set_active_handles and initialize_thread_local_storage 3371 // Note: on solaris initialize_thread_local_storage() will (indirectly) 3372 // change the stack size recorded here to one based on the java thread 3373 // stacksize. This adjusted size is what is used to figure the placement 3374 // of the guard pages. 3375 main_thread->record_stack_base_and_size(); 3376 main_thread->initialize_thread_local_storage(); 3377 3378 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3379 3380 if (!main_thread->set_as_starting_thread()) { 3381 vm_shutdown_during_initialization( 3382 "Failed necessary internal allocation. Out of swap space"); 3383 delete main_thread; 3384 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3385 return JNI_ENOMEM; 3386 } 3387 3388 // Enable guard page *after* os::create_main_thread(), otherwise it would 3389 // crash Linux VM, see notes in os_linux.cpp. 3390 main_thread->create_stack_guard_pages(); 3391 3392 // Initialize Java-Level synchronization subsystem 3393 ObjectMonitor::Initialize() ; 3394 3395 // Second phase of bootstrapping, VM is about entering multi-thread mode 3396 MemTracker::bootstrap_multi_thread(); 3397 3398 // Initialize global modules 3399 jint status = init_globals(); 3400 if (status != JNI_OK) { 3401 delete main_thread; 3402 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3403 return status; 3404 } 3405 3406 // Should be done after the heap is fully created 3407 main_thread->cache_global_variables(); 3408 3409 HandleMark hm; 3410 3411 { MutexLocker mu(Threads_lock); 3412 Threads::add(main_thread); 3413 } 3414 3415 // Any JVMTI raw monitors entered in onload will transition into 3416 // real raw monitor. VM is setup enough here for raw monitor enter. 3417 JvmtiExport::transition_pending_onload_raw_monitors(); 3418 3419 if (VerifyBeforeGC && 3420 Universe::heap()->total_collections() >= VerifyGCStartAt) { 3421 Universe::heap()->prepare_for_verify(); 3422 Universe::verify(); // make sure we're starting with a clean slate 3423 } 3424 3425 // Fully start NMT 3426 MemTracker::start(); 3427 3428 // Create the VMThread 3429 { TraceTime timer("Start VMThread", TraceStartupTime); 3430 VMThread::create(); 3431 Thread* vmthread = VMThread::vm_thread(); 3432 3433 if (!os::create_thread(vmthread, os::vm_thread)) 3434 vm_exit_during_initialization("Cannot create VM thread. Out of system resources."); 3435 3436 // Wait for the VM thread to become ready, and VMThread::run to initialize 3437 // Monitors can have spurious returns, must always check another state flag 3438 { 3439 MutexLocker ml(Notify_lock); 3440 os::start_thread(vmthread); 3441 while (vmthread->active_handles() == NULL) { 3442 Notify_lock->wait(); 3443 } 3444 } 3445 } 3446 3447 assert (Universe::is_fully_initialized(), "not initialized"); 3448 EXCEPTION_MARK; 3449 3450 // At this point, the Universe is initialized, but we have not executed 3451 // any byte code. Now is a good time (the only time) to dump out the 3452 // internal state of the JVM for sharing. 3453 if (DumpSharedSpaces) { 3454 MetaspaceShared::preload_and_dump(CHECK_0); 3455 ShouldNotReachHere(); 3456 } 3457 3458 // Always call even when there are not JVMTI environments yet, since environments 3459 // may be attached late and JVMTI must track phases of VM execution 3460 JvmtiExport::enter_start_phase(); 3461 3462 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3463 JvmtiExport::post_vm_start(); 3464 3465 { 3466 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3467 3468 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3469 create_vm_init_libraries(); 3470 } 3471 3472 if (InitializeJavaLangString) { 3473 initialize_class(vmSymbols::java_lang_String(), CHECK_0); 3474 } else { 3475 warning("java.lang.String not initialized"); 3476 } 3477 3478 if (AggressiveOpts) { 3479 { 3480 // Forcibly initialize java/util/HashMap and mutate the private 3481 // static final "frontCacheEnabled" field before we start creating instances 3482#ifdef ASSERT 3483 Klass* tmp_k = SystemDictionary::find(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3484 assert(tmp_k == NULL, "java/util/HashMap should not be loaded yet"); 3485#endif 3486 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_util_HashMap(), Handle(), Handle(), CHECK_0); 3487 KlassHandle k = KlassHandle(THREAD, k_o); 3488 guarantee(k.not_null(), "Must find java/util/HashMap"); 3489 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3490 ik->initialize(CHECK_0); 3491 fieldDescriptor fd; 3492 // Possible we might not find this field; if so, don't break 3493 if (ik->find_local_field(vmSymbols::frontCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3494 k()->java_mirror()->bool_field_put(fd.offset(), true); 3495 } 3496 } 3497 3498 if (UseStringCache) { 3499 // Forcibly initialize java/lang/StringValue and mutate the private 3500 // static final "stringCacheEnabled" field before we start creating instances 3501 Klass* k_o = SystemDictionary::resolve_or_null(vmSymbols::java_lang_StringValue(), Handle(), Handle(), CHECK_0); 3502 // Possible that StringValue isn't present: if so, silently don't break 3503 if (k_o != NULL) { 3504 KlassHandle k = KlassHandle(THREAD, k_o); 3505 instanceKlassHandle ik = instanceKlassHandle(THREAD, k()); 3506 ik->initialize(CHECK_0); 3507 fieldDescriptor fd; 3508 // Possible we might not find this field: if so, silently don't break 3509 if (ik->find_local_field(vmSymbols::stringCacheEnabled_name(), vmSymbols::bool_signature(), &fd)) { 3510 k()->java_mirror()->bool_field_put(fd.offset(), true); 3511 } 3512 } 3513 } 3514 } 3515 3516 // Initialize java_lang.System (needed before creating the thread) 3517 if (InitializeJavaLangSystem) { 3518 initialize_class(vmSymbols::java_lang_System(), CHECK_0); 3519 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK_0); 3520 Handle thread_group = create_initial_thread_group(CHECK_0); 3521 Universe::set_main_thread_group(thread_group()); 3522 initialize_class(vmSymbols::java_lang_Thread(), CHECK_0); 3523 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK_0); 3524 main_thread->set_threadObj(thread_object); 3525 // Set thread status to running since main thread has 3526 // been started and running. 3527 java_lang_Thread::set_thread_status(thread_object, 3528 java_lang_Thread::RUNNABLE); 3529 3530 // The VM preresolve methods to these classes. Make sure that get initialized 3531 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK_0); 3532 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK_0); 3533 // The VM creates & returns objects of this class. Make sure it's initialized. 3534 initialize_class(vmSymbols::java_lang_Class(), CHECK_0); 3535 call_initializeSystemClass(CHECK_0); 3536 3537 // get the Java runtime name after java.lang.System is initialized 3538 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3539 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3540 } else { 3541 warning("java.lang.System not initialized"); 3542 } 3543 3544 // an instance of OutOfMemory exception has been allocated earlier 3545 if (InitializeJavaLangExceptionsErrors) { 3546 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK_0); 3547 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK_0); 3548 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK_0); 3549 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK_0); 3550 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK_0); 3551 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK_0); 3552 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK_0); 3553 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK_0); 3554 } else { 3555 warning("java.lang.OutOfMemoryError has not been initialized"); 3556 warning("java.lang.NullPointerException has not been initialized"); 3557 warning("java.lang.ClassCastException has not been initialized"); 3558 warning("java.lang.ArrayStoreException has not been initialized"); 3559 warning("java.lang.ArithmeticException has not been initialized"); 3560 warning("java.lang.StackOverflowError has not been initialized"); 3561 warning("java.lang.IllegalArgumentException has not been initialized"); 3562 } 3563 } 3564 3565 // See : bugid 4211085. 3566 // Background : the static initializer of java.lang.Compiler tries to read 3567 // property"java.compiler" and read & write property "java.vm.info". 3568 // When a security manager is installed through the command line 3569 // option "-Djava.security.manager", the above properties are not 3570 // readable and the static initializer for java.lang.Compiler fails 3571 // resulting in a NoClassDefFoundError. This can happen in any 3572 // user code which calls methods in java.lang.Compiler. 3573 // Hack : the hack is to pre-load and initialize this class, so that only 3574 // system domains are on the stack when the properties are read. 3575 // Currently even the AWT code has calls to methods in java.lang.Compiler. 3576 // On the classic VM, java.lang.Compiler is loaded very early to load the JIT. 3577 // Future Fix : the best fix is to grant everyone permissions to read "java.compiler" and 3578 // read and write"java.vm.info" in the default policy file. See bugid 4211383 3579 // Once that is done, we should remove this hack. 3580 initialize_class(vmSymbols::java_lang_Compiler(), CHECK_0); 3581 3582 // More hackery - the static initializer of java.lang.Compiler adds the string "nojit" to 3583 // the java.vm.info property if no jit gets loaded through java.lang.Compiler (the hotspot 3584 // compiler does not get loaded through java.lang.Compiler). "java -version" with the 3585 // hotspot vm says "nojit" all the time which is confusing. So, we reset it here. 3586 // This should also be taken out as soon as 4211383 gets fixed. 3587 reset_vm_info_property(CHECK_0); 3588 3589 quicken_jni_functions(); 3590 3591 // Must be run after init_ft which initializes ft_enabled 3592 if (TRACE_INITIALIZE() != JNI_OK) { 3593 vm_exit_during_initialization("Failed to initialize tracing backend"); 3594 } 3595 3596 // Set flag that basic initialization has completed. Used by exceptions and various 3597 // debug stuff, that does not work until all basic classes have been initialized. 3598 set_init_completed(); 3599 3600#ifndef USDT2 3601 HS_DTRACE_PROBE(hotspot, vm__init__end); 3602#else /* USDT2 */ 3603 HOTSPOT_VM_INIT_END(); 3604#endif /* USDT2 */ 3605 3606 // record VM initialization completion time 3607#if INCLUDE_MANAGEMENT 3608 Management::record_vm_init_completed(); 3609#endif // INCLUDE_MANAGEMENT 3610 3611 // Compute system loader. Note that this has to occur after set_init_completed, since 3612 // valid exceptions may be thrown in the process. 3613 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3614 // set_init_completed has just been called, causing exceptions not to be shortcut 3615 // anymore. We call vm_exit_during_initialization directly instead. 3616 SystemDictionary::compute_java_system_loader(THREAD); 3617 if (HAS_PENDING_EXCEPTION) { 3618 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3619 } 3620 3621#ifndef SERIALGC 3622 // Support for ConcurrentMarkSweep. This should be cleaned up 3623 // and better encapsulated. The ugly nested if test would go away 3624 // once things are properly refactored. XXX YSR 3625 if (UseConcMarkSweepGC || UseG1GC) { 3626 if (UseConcMarkSweepGC) { 3627 ConcurrentMarkSweepThread::makeSurrogateLockerThread(THREAD); 3628 } else { 3629 ConcurrentMarkThread::makeSurrogateLockerThread(THREAD); 3630 } 3631 if (HAS_PENDING_EXCEPTION) { 3632 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3633 } 3634 } 3635#endif // SERIALGC 3636 3637 // Always call even when there are not JVMTI environments yet, since environments 3638 // may be attached late and JVMTI must track phases of VM execution 3639 JvmtiExport::enter_live_phase(); 3640 3641 // Signal Dispatcher needs to be started before VMInit event is posted 3642 os::signal_init(); 3643 3644 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3645 if (!DisableAttachMechanism) { 3646 if (StartAttachListener || AttachListener::init_at_startup()) { 3647 AttachListener::init(); 3648 } 3649 } 3650 3651 // Launch -Xrun agents 3652 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3653 // back-end can launch with -Xdebug -Xrunjdwp. 3654 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3655 create_vm_init_libraries(); 3656 } 3657 3658 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3659 JvmtiExport::post_vm_initialized(); 3660 3661 if (!TRACE_START()) { 3662 vm_exit_during_initialization(Handle(THREAD, PENDING_EXCEPTION)); 3663 } 3664 3665 if (CleanChunkPoolAsync) { 3666 Chunk::start_chunk_pool_cleaner_task(); 3667 } 3668 3669 // initialize compiler(s) 3670#if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) 3671 CompileBroker::compilation_init(); 3672#endif 3673 3674#if INCLUDE_MANAGEMENT 3675 Management::initialize(THREAD); 3676#endif // INCLUDE_MANAGEMENT 3677 3678 if (HAS_PENDING_EXCEPTION) { 3679 // management agent fails to start possibly due to 3680 // configuration problem and is responsible for printing 3681 // stack trace if appropriate. Simply exit VM. 3682 vm_exit(1); 3683 } 3684 3685 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3686 if (Arguments::has_alloc_profile()) AllocationProfiler::engage(); 3687 if (MemProfiling) MemProfiler::engage(); 3688 StatSampler::engage(); 3689 if (CheckJNICalls) JniPeriodicChecker::engage(); 3690 3691 BiasedLocking::init(); 3692 3693 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3694 call_postVMInitHook(THREAD); 3695 // The Java side of PostVMInitHook.run must deal with all 3696 // exceptions and provide means of diagnosis. 3697 if (HAS_PENDING_EXCEPTION) { 3698 CLEAR_PENDING_EXCEPTION; 3699 } 3700 } 3701 3702 { 3703 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 3704 // Make sure the watcher thread can be started by WatcherThread::start() 3705 // or by dynamic enrollment. 3706 WatcherThread::make_startable(); 3707 // Start up the WatcherThread if there are any periodic tasks 3708 // NOTE: All PeriodicTasks should be registered by now. If they 3709 // aren't, late joiners might appear to start slowly (we might 3710 // take a while to process their first tick). 3711 if (PeriodicTask::num_tasks() > 0) { 3712 WatcherThread::start(); 3713 } 3714 } 3715 3716 // Give os specific code one last chance to start 3717 os::init_3(); 3718 3719 create_vm_timer.end(); 3720#ifdef ASSERT 3721 _vm_complete = true; 3722#endif 3723 return JNI_OK; 3724} 3725 3726// type for the Agent_OnLoad and JVM_OnLoad entry points 3727extern "C" { 3728 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3729} 3730// Find a command line agent library and return its entry point for 3731// -agentlib: -agentpath: -Xrun 3732// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3733static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, const char *on_load_symbols[], size_t num_symbol_entries) { 3734 OnLoadEntry_t on_load_entry = NULL; 3735 void *library = agent->os_lib(); // check if we have looked it up before 3736 3737 if (library == NULL) { 3738 char buffer[JVM_MAXPATHLEN]; 3739 char ebuf[1024]; 3740 const char *name = agent->name(); 3741 const char *msg = "Could not find agent library "; 3742 3743 if (agent->is_absolute_path()) { 3744 library = os::dll_load(name, ebuf, sizeof ebuf); 3745 if (library == NULL) { 3746 const char *sub_msg = " in absolute path, with error: "; 3747 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3748 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3749 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3750 // If we can't find the agent, exit. 3751 vm_exit_during_initialization(buf, NULL); 3752 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3753 } 3754 } else { 3755 // Try to load the agent from the standard dll directory 3756 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3757 name)) { 3758 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3759 } 3760#ifdef KERNEL 3761 // Download instrument dll 3762 if (library == NULL && strcmp(name, "instrument") == 0) { 3763 char *props = Arguments::get_kernel_properties(); 3764 char *home = Arguments::get_java_home(); 3765 const char *fmt = "%s/bin/java %s -Dkernel.background.download=false" 3766 " sun.jkernel.DownloadManager -download client_jvm"; 3767 size_t length = strlen(props) + strlen(home) + strlen(fmt) + 1; 3768 char *cmd = NEW_C_HEAP_ARRAY(char, length, mtThread); 3769 jio_snprintf(cmd, length, fmt, home, props); 3770 int status = os::fork_and_exec(cmd); 3771 FreeHeap(props); 3772 if (status == -1) { 3773 warning(cmd); 3774 vm_exit_during_initialization("fork_and_exec failed: %s", 3775 strerror(errno)); 3776 } 3777 FREE_C_HEAP_ARRAY(char, cmd, mtThread); 3778 // when this comes back the instrument.dll should be where it belongs. 3779 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3780 } 3781#endif // KERNEL 3782 if (library == NULL) { // Try the local directory 3783 char ns[1] = {0}; 3784 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3785 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3786 } 3787 if (library == NULL) { 3788 const char *sub_msg = " on the library path, with error: "; 3789 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3790 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3791 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3792 // If we can't find the agent, exit. 3793 vm_exit_during_initialization(buf, NULL); 3794 FREE_C_HEAP_ARRAY(char, buf, mtThread); 3795 } 3796 } 3797 } 3798 agent->set_os_lib(library); 3799 } 3800 3801 // Find the OnLoad function. 3802 for (size_t symbol_index = 0; symbol_index < num_symbol_entries; symbol_index++) { 3803 on_load_entry = CAST_TO_FN_PTR(OnLoadEntry_t, os::dll_lookup(library, on_load_symbols[symbol_index])); 3804 if (on_load_entry != NULL) break; 3805 } 3806 return on_load_entry; 3807} 3808 3809// Find the JVM_OnLoad entry point 3810static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3811 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3812 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3813} 3814 3815// Find the Agent_OnLoad entry point 3816static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3817 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3818 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3819} 3820 3821// For backwards compatibility with -Xrun 3822// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3823// treated like -agentpath: 3824// Must be called before agent libraries are created 3825void Threads::convert_vm_init_libraries_to_agents() { 3826 AgentLibrary* agent; 3827 AgentLibrary* next; 3828 3829 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3830 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3831 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3832 3833 // If there is an JVM_OnLoad function it will get called later, 3834 // otherwise see if there is an Agent_OnLoad 3835 if (on_load_entry == NULL) { 3836 on_load_entry = lookup_agent_on_load(agent); 3837 if (on_load_entry != NULL) { 3838 // switch it to the agent list -- so that Agent_OnLoad will be called, 3839 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3840 Arguments::convert_library_to_agent(agent); 3841 } else { 3842 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3843 } 3844 } 3845 } 3846} 3847 3848// Create agents for -agentlib: -agentpath: and converted -Xrun 3849// Invokes Agent_OnLoad 3850// Called very early -- before JavaThreads exist 3851void Threads::create_vm_init_agents() { 3852 extern struct JavaVM_ main_vm; 3853 AgentLibrary* agent; 3854 3855 JvmtiExport::enter_onload_phase(); 3856 3857 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3858 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3859 3860 if (on_load_entry != NULL) { 3861 // Invoke the Agent_OnLoad function 3862 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3863 if (err != JNI_OK) { 3864 vm_exit_during_initialization("agent library failed to init", agent->name()); 3865 } 3866 } else { 3867 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3868 } 3869 } 3870 JvmtiExport::enter_primordial_phase(); 3871} 3872 3873extern "C" { 3874 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3875} 3876 3877void Threads::shutdown_vm_agents() { 3878 // Send any Agent_OnUnload notifications 3879 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3880 extern struct JavaVM_ main_vm; 3881 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3882 3883 // Find the Agent_OnUnload function. 3884 for (uint symbol_index = 0; symbol_index < ARRAY_SIZE(on_unload_symbols); symbol_index++) { 3885 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3886 os::dll_lookup(agent->os_lib(), on_unload_symbols[symbol_index])); 3887 3888 // Invoke the Agent_OnUnload function 3889 if (unload_entry != NULL) { 3890 JavaThread* thread = JavaThread::current(); 3891 ThreadToNativeFromVM ttn(thread); 3892 HandleMark hm(thread); 3893 (*unload_entry)(&main_vm); 3894 break; 3895 } 3896 } 3897 } 3898} 3899 3900// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3901// Invokes JVM_OnLoad 3902void Threads::create_vm_init_libraries() { 3903 extern struct JavaVM_ main_vm; 3904 AgentLibrary* agent; 3905 3906 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3907 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3908 3909 if (on_load_entry != NULL) { 3910 // Invoke the JVM_OnLoad function 3911 JavaThread* thread = JavaThread::current(); 3912 ThreadToNativeFromVM ttn(thread); 3913 HandleMark hm(thread); 3914 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3915 if (err != JNI_OK) { 3916 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3917 } 3918 } else { 3919 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3920 } 3921 } 3922} 3923 3924// Last thread running calls java.lang.Shutdown.shutdown() 3925void JavaThread::invoke_shutdown_hooks() { 3926 HandleMark hm(this); 3927 3928 // We could get here with a pending exception, if so clear it now. 3929 if (this->has_pending_exception()) { 3930 this->clear_pending_exception(); 3931 } 3932 3933 EXCEPTION_MARK; 3934 Klass* k = 3935 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3936 THREAD); 3937 if (k != NULL) { 3938 // SystemDictionary::resolve_or_null will return null if there was 3939 // an exception. If we cannot load the Shutdown class, just don't 3940 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3941 // and finalizers (if runFinalizersOnExit is set) won't be run. 3942 // Note that if a shutdown hook was registered or runFinalizersOnExit 3943 // was called, the Shutdown class would have already been loaded 3944 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3945 instanceKlassHandle shutdown_klass (THREAD, k); 3946 JavaValue result(T_VOID); 3947 JavaCalls::call_static(&result, 3948 shutdown_klass, 3949 vmSymbols::shutdown_method_name(), 3950 vmSymbols::void_method_signature(), 3951 THREAD); 3952 } 3953 CLEAR_PENDING_EXCEPTION; 3954} 3955 3956// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3957// the program falls off the end of main(). Another VM exit path is through 3958// vm_exit() when the program calls System.exit() to return a value or when 3959// there is a serious error in VM. The two shutdown paths are not exactly 3960// the same, but they share Shutdown.shutdown() at Java level and before_exit() 3961// and VM_Exit op at VM level. 3962// 3963// Shutdown sequence: 3964// + Shutdown native memory tracking if it is on 3965// + Wait until we are the last non-daemon thread to execute 3966// <-- every thing is still working at this moment --> 3967// + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3968// shutdown hooks, run finalizers if finalization-on-exit 3969// + Call before_exit(), prepare for VM exit 3970// > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3971// currently the only user of this mechanism is File.deleteOnExit()) 3972// > stop flat profiler, StatSampler, watcher thread, CMS threads, 3973// post thread end and vm death events to JVMTI, 3974// stop signal thread 3975// + Call JavaThread::exit(), it will: 3976// > release JNI handle blocks, remove stack guard pages 3977// > remove this thread from Threads list 3978// <-- no more Java code from this thread after this point --> 3979// + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3980// the compiler threads at safepoint 3981// <-- do not use anything that could get blocked by Safepoint --> 3982// + Disable tracing at JNI/JVM barriers 3983// + Set _vm_exited flag for threads that are still running native code 3984// + Delete this thread 3985// + Call exit_globals() 3986// > deletes tty 3987// > deletes PerfMemory resources 3988// + Return to caller 3989 3990bool Threads::destroy_vm() { 3991 JavaThread* thread = JavaThread::current(); 3992 3993#ifdef ASSERT 3994 _vm_complete = false; 3995#endif 3996 // Wait until we are the last non-daemon thread to execute 3997 { MutexLocker nu(Threads_lock); 3998 while (Threads::number_of_non_daemon_threads() > 1 ) 3999 // This wait should make safepoint checks, wait without a timeout, 4000 // and wait as a suspend-equivalent condition. 4001 // 4002 // Note: If the FlatProfiler is running and this thread is waiting 4003 // for another non-daemon thread to finish, then the FlatProfiler 4004 // is waiting for the external suspend request on this thread to 4005 // complete. wait_for_ext_suspend_completion() will eventually 4006 // timeout, but that takes time. Making this wait a suspend- 4007 // equivalent condition solves that timeout problem. 4008 // 4009 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 4010 Mutex::_as_suspend_equivalent_flag); 4011 } 4012 4013 // Shutdown NMT before exit. Otherwise, 4014 // it will run into trouble when system destroys static variables. 4015 MemTracker::shutdown(MemTracker::NMT_normal); 4016 4017 // Hang forever on exit if we are reporting an error. 4018 if (ShowMessageBoxOnError && is_error_reported()) { 4019 os::infinite_sleep(); 4020 } 4021 os::wait_for_keypress_at_exit(); 4022 4023 if (JDK_Version::is_jdk12x_version()) { 4024 // We are the last thread running, so check if finalizers should be run. 4025 // For 1.3 or later this is done in thread->invoke_shutdown_hooks() 4026 HandleMark rm(thread); 4027 Universe::run_finalizers_on_exit(); 4028 } else { 4029 // run Java level shutdown hooks 4030 thread->invoke_shutdown_hooks(); 4031 } 4032 4033 before_exit(thread); 4034 4035 thread->exit(true); 4036 4037 // Stop VM thread. 4038 { 4039 // 4945125 The vm thread comes to a safepoint during exit. 4040 // GC vm_operations can get caught at the safepoint, and the 4041 // heap is unparseable if they are caught. Grab the Heap_lock 4042 // to prevent this. The GC vm_operations will not be able to 4043 // queue until after the vm thread is dead. 4044 // After this point, we'll never emerge out of the safepoint before 4045 // the VM exits, so concurrent GC threads do not need to be explicitly 4046 // stopped; they remain inactive until the process exits. 4047 // Note: some concurrent G1 threads may be running during a safepoint, 4048 // but these will not be accessing the heap, just some G1-specific side 4049 // data structures that are not accessed by any other threads but them 4050 // after this point in a terminal safepoint. 4051 4052 MutexLocker ml(Heap_lock); 4053 4054 VMThread::wait_for_vm_thread_exit(); 4055 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4056 VMThread::destroy(); 4057 } 4058 4059 // clean up ideal graph printers 4060#if defined(COMPILER2) && !defined(PRODUCT) 4061 IdealGraphPrinter::clean_up(); 4062#endif 4063 4064 // Now, all Java threads are gone except daemon threads. Daemon threads 4065 // running Java code or in VM are stopped by the Safepoint. However, 4066 // daemon threads executing native code are still running. But they 4067 // will be stopped at native=>Java/VM barriers. Note that we can't 4068 // simply kill or suspend them, as it is inherently deadlock-prone. 4069 4070#ifndef PRODUCT 4071 // disable function tracing at JNI/JVM barriers 4072 TraceJNICalls = false; 4073 TraceJVMCalls = false; 4074 TraceRuntimeCalls = false; 4075#endif 4076 4077 VM_Exit::set_vm_exited(); 4078 4079 notify_vm_shutdown(); 4080 4081 delete thread; 4082 4083 // exit_globals() will delete tty 4084 exit_globals(); 4085 4086 return true; 4087} 4088 4089 4090jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4091 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4092 return is_supported_jni_version(version); 4093} 4094 4095 4096jboolean Threads::is_supported_jni_version(jint version) { 4097 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4098 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4099 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4100 return JNI_FALSE; 4101} 4102 4103 4104void Threads::add(JavaThread* p, bool force_daemon) { 4105 // The threads lock must be owned at this point 4106 assert_locked_or_safepoint(Threads_lock); 4107 4108 // See the comment for this method in thread.hpp for its purpose and 4109 // why it is called here. 4110 p->initialize_queues(); 4111 p->set_next(_thread_list); 4112 _thread_list = p; 4113 _number_of_threads++; 4114 oop threadObj = p->threadObj(); 4115 bool daemon = true; 4116 // Bootstrapping problem: threadObj can be null for initial 4117 // JavaThread (or for threads attached via JNI) 4118 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4119 _number_of_non_daemon_threads++; 4120 daemon = false; 4121 } 4122 4123 p->set_safepoint_visible(true); 4124 4125 ThreadService::add_thread(p, daemon); 4126 4127 // Possible GC point. 4128 Events::log(p, "Thread added: " INTPTR_FORMAT, p); 4129} 4130 4131void Threads::remove(JavaThread* p) { 4132 // Extra scope needed for Thread_lock, so we can check 4133 // that we do not remove thread without safepoint code notice 4134 { MutexLocker ml(Threads_lock); 4135 4136 assert(includes(p), "p must be present"); 4137 4138 JavaThread* current = _thread_list; 4139 JavaThread* prev = NULL; 4140 4141 while (current != p) { 4142 prev = current; 4143 current = current->next(); 4144 } 4145 4146 if (prev) { 4147 prev->set_next(current->next()); 4148 } else { 4149 _thread_list = p->next(); 4150 } 4151 _number_of_threads--; 4152 oop threadObj = p->threadObj(); 4153 bool daemon = true; 4154 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4155 _number_of_non_daemon_threads--; 4156 daemon = false; 4157 4158 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4159 // on destroy_vm will wake up. 4160 if (number_of_non_daemon_threads() == 1) 4161 Threads_lock->notify_all(); 4162 } 4163 ThreadService::remove_thread(p, daemon); 4164 4165 // Make sure that safepoint code disregard this thread. This is needed since 4166 // the thread might mess around with locks after this point. This can cause it 4167 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4168 // of this thread since it is removed from the queue. 4169 p->set_terminated_value(); 4170 4171 // Now, this thread is not visible to safepoint 4172 p->set_safepoint_visible(false); 4173 // once the thread becomes safepoint invisible, we can not use its per-thread 4174 // recorder. And Threads::do_threads() no longer walks this thread, so we have 4175 // to release its per-thread recorder here. 4176 MemTracker::thread_exiting(p); 4177 } // unlock Threads_lock 4178 4179 // Since Events::log uses a lock, we grab it outside the Threads_lock 4180 Events::log(p, "Thread exited: " INTPTR_FORMAT, p); 4181} 4182 4183// Threads_lock must be held when this is called (or must be called during a safepoint) 4184bool Threads::includes(JavaThread* p) { 4185 assert(Threads_lock->is_locked(), "sanity check"); 4186 ALL_JAVA_THREADS(q) { 4187 if (q == p ) { 4188 return true; 4189 } 4190 } 4191 return false; 4192} 4193 4194// Operations on the Threads list for GC. These are not explicitly locked, 4195// but the garbage collector must provide a safe context for them to run. 4196// In particular, these things should never be called when the Threads_lock 4197// is held by some other thread. (Note: the Safepoint abstraction also 4198// uses the Threads_lock to gurantee this property. It also makes sure that 4199// all threads gets blocked when exiting or starting). 4200 4201void Threads::oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4202 ALL_JAVA_THREADS(p) { 4203 p->oops_do(f, cld_f, cf); 4204 } 4205 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4206} 4207 4208void Threads::possibly_parallel_oops_do(OopClosure* f, CLDToOopClosure* cld_f, CodeBlobClosure* cf) { 4209 // Introduce a mechanism allowing parallel threads to claim threads as 4210 // root groups. Overhead should be small enough to use all the time, 4211 // even in sequential code. 4212 SharedHeap* sh = SharedHeap::heap(); 4213 // Cannot yet substitute active_workers for n_par_threads 4214 // because of G1CollectedHeap::verify() use of 4215 // SharedHeap::process_strong_roots(). n_par_threads == 0 will 4216 // turn off parallelism in process_strong_roots while active_workers 4217 // is being used for parallelism elsewhere. 4218 bool is_par = sh->n_par_threads() > 0; 4219 assert(!is_par || 4220 (SharedHeap::heap()->n_par_threads() == 4221 SharedHeap::heap()->workers()->active_workers()), "Mismatch"); 4222 int cp = SharedHeap::heap()->strong_roots_parity(); 4223 ALL_JAVA_THREADS(p) { 4224 if (p->claim_oops_do(is_par, cp)) { 4225 p->oops_do(f, cld_f, cf); 4226 } 4227 } 4228 VMThread* vmt = VMThread::vm_thread(); 4229 if (vmt->claim_oops_do(is_par, cp)) { 4230 vmt->oops_do(f, cld_f, cf); 4231 } 4232} 4233 4234#ifndef SERIALGC 4235// Used by ParallelScavenge 4236void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4237 ALL_JAVA_THREADS(p) { 4238 q->enqueue(new ThreadRootsTask(p)); 4239 } 4240 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4241} 4242 4243// Used by Parallel Old 4244void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4245 ALL_JAVA_THREADS(p) { 4246 q->enqueue(new ThreadRootsMarkingTask(p)); 4247 } 4248 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4249} 4250#endif // SERIALGC 4251 4252void Threads::nmethods_do(CodeBlobClosure* cf) { 4253 ALL_JAVA_THREADS(p) { 4254 p->nmethods_do(cf); 4255 } 4256 VMThread::vm_thread()->nmethods_do(cf); 4257} 4258 4259void Threads::metadata_do(void f(Metadata*)) { 4260 ALL_JAVA_THREADS(p) { 4261 p->metadata_do(f); 4262 } 4263} 4264 4265void Threads::gc_epilogue() { 4266 ALL_JAVA_THREADS(p) { 4267 p->gc_epilogue(); 4268 } 4269} 4270 4271void Threads::gc_prologue() { 4272 ALL_JAVA_THREADS(p) { 4273 p->gc_prologue(); 4274 } 4275} 4276 4277void Threads::deoptimized_wrt_marked_nmethods() { 4278 ALL_JAVA_THREADS(p) { 4279 p->deoptimized_wrt_marked_nmethods(); 4280 } 4281} 4282 4283 4284// Get count Java threads that are waiting to enter the specified monitor. 4285GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4286 address monitor, bool doLock) { 4287 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4288 "must grab Threads_lock or be at safepoint"); 4289 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4290 4291 int i = 0; 4292 { 4293 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4294 ALL_JAVA_THREADS(p) { 4295 if (p->is_Compiler_thread()) continue; 4296 4297 address pending = (address)p->current_pending_monitor(); 4298 if (pending == monitor) { // found a match 4299 if (i < count) result->append(p); // save the first count matches 4300 i++; 4301 } 4302 } 4303 } 4304 return result; 4305} 4306 4307 4308JavaThread *Threads::owning_thread_from_monitor_owner(address owner, bool doLock) { 4309 assert(doLock || 4310 Threads_lock->owned_by_self() || 4311 SafepointSynchronize::is_at_safepoint(), 4312 "must grab Threads_lock or be at safepoint"); 4313 4314 // NULL owner means not locked so we can skip the search 4315 if (owner == NULL) return NULL; 4316 4317 { 4318 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4319 ALL_JAVA_THREADS(p) { 4320 // first, see if owner is the address of a Java thread 4321 if (owner == (address)p) return p; 4322 } 4323 } 4324 assert(UseHeavyMonitors == false, "Did not find owning Java thread with UseHeavyMonitors enabled"); 4325 if (UseHeavyMonitors) return NULL; 4326 4327 // 4328 // If we didn't find a matching Java thread and we didn't force use of 4329 // heavyweight monitors, then the owner is the stack address of the 4330 // Lock Word in the owning Java thread's stack. 4331 // 4332 JavaThread* the_owner = NULL; 4333 { 4334 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4335 ALL_JAVA_THREADS(q) { 4336 if (q->is_lock_owned(owner)) { 4337 the_owner = q; 4338 break; 4339 } 4340 } 4341 } 4342 assert(the_owner != NULL, "Did not find owning Java thread for lock word address"); 4343 return the_owner; 4344} 4345 4346// Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4347void Threads::print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks) { 4348 char buf[32]; 4349 st->print_cr(os::local_time_string(buf, sizeof(buf))); 4350 4351 st->print_cr("Full thread dump %s (%s %s):", 4352 Abstract_VM_Version::vm_name(), 4353 Abstract_VM_Version::vm_release(), 4354 Abstract_VM_Version::vm_info_string() 4355 ); 4356 st->cr(); 4357 4358#ifndef SERIALGC 4359 // Dump concurrent locks 4360 ConcurrentLocksDump concurrent_locks; 4361 if (print_concurrent_locks) { 4362 concurrent_locks.dump_at_safepoint(); 4363 } 4364#endif // SERIALGC 4365 4366 ALL_JAVA_THREADS(p) { 4367 ResourceMark rm; 4368 p->print_on(st); 4369 if (print_stacks) { 4370 if (internal_format) { 4371 p->trace_stack(); 4372 } else { 4373 p->print_stack_on(st); 4374 } 4375 } 4376 st->cr(); 4377#ifndef SERIALGC 4378 if (print_concurrent_locks) { 4379 concurrent_locks.print_locks_on(p, st); 4380 } 4381#endif // SERIALGC 4382 } 4383 4384 VMThread::vm_thread()->print_on(st); 4385 st->cr(); 4386 Universe::heap()->print_gc_threads_on(st); 4387 WatcherThread* wt = WatcherThread::watcher_thread(); 4388 if (wt != NULL) { 4389 wt->print_on(st); 4390 st->cr(); 4391 } 4392 CompileBroker::print_compiler_threads_on(st); 4393 st->flush(); 4394} 4395 4396// Threads::print_on_error() is called by fatal error handler. It's possible 4397// that VM is not at safepoint and/or current thread is inside signal handler. 4398// Don't print stack trace, as the stack may not be walkable. Don't allocate 4399// memory (even in resource area), it might deadlock the error handler. 4400void Threads::print_on_error(outputStream* st, Thread* current, char* buf, int buflen) { 4401 bool found_current = false; 4402 st->print_cr("Java Threads: ( => current thread )"); 4403 ALL_JAVA_THREADS(thread) { 4404 bool is_current = (current == thread); 4405 found_current = found_current || is_current; 4406 4407 st->print("%s", is_current ? "=>" : " "); 4408 4409 st->print(PTR_FORMAT, thread); 4410 st->print(" "); 4411 thread->print_on_error(st, buf, buflen); 4412 st->cr(); 4413 } 4414 st->cr(); 4415 4416 st->print_cr("Other Threads:"); 4417 if (VMThread::vm_thread()) { 4418 bool is_current = (current == VMThread::vm_thread()); 4419 found_current = found_current || is_current; 4420 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4421 4422 st->print(PTR_FORMAT, VMThread::vm_thread()); 4423 st->print(" "); 4424 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4425 st->cr(); 4426 } 4427 WatcherThread* wt = WatcherThread::watcher_thread(); 4428 if (wt != NULL) { 4429 bool is_current = (current == wt); 4430 found_current = found_current || is_current; 4431 st->print("%s", is_current ? "=>" : " "); 4432 4433 st->print(PTR_FORMAT, wt); 4434 st->print(" "); 4435 wt->print_on_error(st, buf, buflen); 4436 st->cr(); 4437 } 4438 if (!found_current) { 4439 st->cr(); 4440 st->print("=>" PTR_FORMAT " (exited) ", current); 4441 current->print_on_error(st, buf, buflen); 4442 st->cr(); 4443 } 4444} 4445 4446// Internal SpinLock and Mutex 4447// Based on ParkEvent 4448 4449// Ad-hoc mutual exclusion primitives: SpinLock and Mux 4450// 4451// We employ SpinLocks _only for low-contention, fixed-length 4452// short-duration critical sections where we're concerned 4453// about native mutex_t or HotSpot Mutex:: latency. 4454// The mux construct provides a spin-then-block mutual exclusion 4455// mechanism. 4456// 4457// Testing has shown that contention on the ListLock guarding gFreeList 4458// is common. If we implement ListLock as a simple SpinLock it's common 4459// for the JVM to devolve to yielding with little progress. This is true 4460// despite the fact that the critical sections protected by ListLock are 4461// extremely short. 4462// 4463// TODO-FIXME: ListLock should be of type SpinLock. 4464// We should make this a 1st-class type, integrated into the lock 4465// hierarchy as leaf-locks. Critically, the SpinLock structure 4466// should have sufficient padding to avoid false-sharing and excessive 4467// cache-coherency traffic. 4468 4469 4470typedef volatile int SpinLockT ; 4471 4472void Thread::SpinAcquire (volatile int * adr, const char * LockName) { 4473 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4474 return ; // normal fast-path return 4475 } 4476 4477 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4478 TEVENT (SpinAcquire - ctx) ; 4479 int ctr = 0 ; 4480 int Yields = 0 ; 4481 for (;;) { 4482 while (*adr != 0) { 4483 ++ctr ; 4484 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4485 if (Yields > 5) { 4486 // Consider using a simple NakedSleep() instead. 4487 // Then SpinAcquire could be called by non-JVM threads 4488 Thread::current()->_ParkEvent->park(1) ; 4489 } else { 4490 os::NakedYield() ; 4491 ++Yields ; 4492 } 4493 } else { 4494 SpinPause() ; 4495 } 4496 } 4497 if (Atomic::cmpxchg (1, adr, 0) == 0) return ; 4498 } 4499} 4500 4501void Thread::SpinRelease (volatile int * adr) { 4502 assert (*adr != 0, "invariant") ; 4503 OrderAccess::fence() ; // guarantee at least release consistency. 4504 // Roach-motel semantics. 4505 // It's safe if subsequent LDs and STs float "up" into the critical section, 4506 // but prior LDs and STs within the critical section can't be allowed 4507 // to reorder or float past the ST that releases the lock. 4508 *adr = 0 ; 4509} 4510 4511// muxAcquire and muxRelease: 4512// 4513// * muxAcquire and muxRelease support a single-word lock-word construct. 4514// The LSB of the word is set IFF the lock is held. 4515// The remainder of the word points to the head of a singly-linked list 4516// of threads blocked on the lock. 4517// 4518// * The current implementation of muxAcquire-muxRelease uses its own 4519// dedicated Thread._MuxEvent instance. If we're interested in 4520// minimizing the peak number of extant ParkEvent instances then 4521// we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4522// as certain invariants were satisfied. Specifically, care would need 4523// to be taken with regards to consuming unpark() "permits". 4524// A safe rule of thumb is that a thread would never call muxAcquire() 4525// if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4526// park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4527// consume an unpark() permit intended for monitorenter, for instance. 4528// One way around this would be to widen the restricted-range semaphore 4529// implemented in park(). Another alternative would be to provide 4530// multiple instances of the PlatformEvent() for each thread. One 4531// instance would be dedicated to muxAcquire-muxRelease, for instance. 4532// 4533// * Usage: 4534// -- Only as leaf locks 4535// -- for short-term locking only as muxAcquire does not perform 4536// thread state transitions. 4537// 4538// Alternatives: 4539// * We could implement muxAcquire and muxRelease with MCS or CLH locks 4540// but with parking or spin-then-park instead of pure spinning. 4541// * Use Taura-Oyama-Yonenzawa locks. 4542// * It's possible to construct a 1-0 lock if we encode the lockword as 4543// (List,LockByte). Acquire will CAS the full lockword while Release 4544// will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4545// acquiring threads use timers (ParkTimed) to detect and recover from 4546// the stranding window. Thread/Node structures must be aligned on 256-byte 4547// boundaries by using placement-new. 4548// * Augment MCS with advisory back-link fields maintained with CAS(). 4549// Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4550// The validity of the backlinks must be ratified before we trust the value. 4551// If the backlinks are invalid the exiting thread must back-track through the 4552// the forward links, which are always trustworthy. 4553// * Add a successor indication. The LockWord is currently encoded as 4554// (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4555// to provide the usual futile-wakeup optimization. 4556// See RTStt for details. 4557// * Consider schedctl.sc_nopreempt to cover the critical section. 4558// 4559 4560 4561typedef volatile intptr_t MutexT ; // Mux Lock-word 4562enum MuxBits { LOCKBIT = 1 } ; 4563 4564void Thread::muxAcquire (volatile intptr_t * Lock, const char * LockName) { 4565 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4566 if (w == 0) return ; 4567 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4568 return ; 4569 } 4570 4571 TEVENT (muxAcquire - Contention) ; 4572 ParkEvent * const Self = Thread::current()->_MuxEvent ; 4573 assert ((intptr_t(Self) & LOCKBIT) == 0, "invariant") ; 4574 for (;;) { 4575 int its = (os::is_MP() ? 100 : 0) + 1 ; 4576 4577 // Optional spin phase: spin-then-park strategy 4578 while (--its >= 0) { 4579 w = *Lock ; 4580 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4581 return ; 4582 } 4583 } 4584 4585 Self->reset() ; 4586 Self->OnList = intptr_t(Lock) ; 4587 // The following fence() isn't _strictly necessary as the subsequent 4588 // CAS() both serializes execution and ratifies the fetched *Lock value. 4589 OrderAccess::fence(); 4590 for (;;) { 4591 w = *Lock ; 4592 if ((w & LOCKBIT) == 0) { 4593 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4594 Self->OnList = 0 ; // hygiene - allows stronger asserts 4595 return ; 4596 } 4597 continue ; // Interference -- *Lock changed -- Just retry 4598 } 4599 assert (w & LOCKBIT, "invariant") ; 4600 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4601 if (Atomic::cmpxchg_ptr (intptr_t(Self)|LOCKBIT, Lock, w) == w) break ; 4602 } 4603 4604 while (Self->OnList != 0) { 4605 Self->park() ; 4606 } 4607 } 4608} 4609 4610void Thread::muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) { 4611 intptr_t w = Atomic::cmpxchg_ptr (LOCKBIT, Lock, 0) ; 4612 if (w == 0) return ; 4613 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4614 return ; 4615 } 4616 4617 TEVENT (muxAcquire - Contention) ; 4618 ParkEvent * ReleaseAfter = NULL ; 4619 if (ev == NULL) { 4620 ev = ReleaseAfter = ParkEvent::Allocate (NULL) ; 4621 } 4622 assert ((intptr_t(ev) & LOCKBIT) == 0, "invariant") ; 4623 for (;;) { 4624 guarantee (ev->OnList == 0, "invariant") ; 4625 int its = (os::is_MP() ? 100 : 0) + 1 ; 4626 4627 // Optional spin phase: spin-then-park strategy 4628 while (--its >= 0) { 4629 w = *Lock ; 4630 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4631 if (ReleaseAfter != NULL) { 4632 ParkEvent::Release (ReleaseAfter) ; 4633 } 4634 return ; 4635 } 4636 } 4637 4638 ev->reset() ; 4639 ev->OnList = intptr_t(Lock) ; 4640 // The following fence() isn't _strictly necessary as the subsequent 4641 // CAS() both serializes execution and ratifies the fetched *Lock value. 4642 OrderAccess::fence(); 4643 for (;;) { 4644 w = *Lock ; 4645 if ((w & LOCKBIT) == 0) { 4646 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4647 ev->OnList = 0 ; 4648 // We call ::Release while holding the outer lock, thus 4649 // artificially lengthening the critical section. 4650 // Consider deferring the ::Release() until the subsequent unlock(), 4651 // after we've dropped the outer lock. 4652 if (ReleaseAfter != NULL) { 4653 ParkEvent::Release (ReleaseAfter) ; 4654 } 4655 return ; 4656 } 4657 continue ; // Interference -- *Lock changed -- Just retry 4658 } 4659 assert (w & LOCKBIT, "invariant") ; 4660 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT ); 4661 if (Atomic::cmpxchg_ptr (intptr_t(ev)|LOCKBIT, Lock, w) == w) break ; 4662 } 4663 4664 while (ev->OnList != 0) { 4665 ev->park() ; 4666 } 4667 } 4668} 4669 4670// Release() must extract a successor from the list and then wake that thread. 4671// It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4672// similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4673// Release() would : 4674// (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4675// (B) Extract a successor from the private list "in-hand" 4676// (C) attempt to CAS() the residual back into *Lock over null. 4677// If there were any newly arrived threads and the CAS() would fail. 4678// In that case Release() would detach the RATs, re-merge the list in-hand 4679// with the RATs and repeat as needed. Alternately, Release() might 4680// detach and extract a successor, but then pass the residual list to the wakee. 4681// The wakee would be responsible for reattaching and remerging before it 4682// competed for the lock. 4683// 4684// Both "pop" and DMR are immune from ABA corruption -- there can be 4685// multiple concurrent pushers, but only one popper or detacher. 4686// This implementation pops from the head of the list. This is unfair, 4687// but tends to provide excellent throughput as hot threads remain hot. 4688// (We wake recently run threads first). 4689 4690void Thread::muxRelease (volatile intptr_t * Lock) { 4691 for (;;) { 4692 const intptr_t w = Atomic::cmpxchg_ptr (0, Lock, LOCKBIT) ; 4693 assert (w & LOCKBIT, "invariant") ; 4694 if (w == LOCKBIT) return ; 4695 ParkEvent * List = (ParkEvent *) (w & ~LOCKBIT) ; 4696 assert (List != NULL, "invariant") ; 4697 assert (List->OnList == intptr_t(Lock), "invariant") ; 4698 ParkEvent * nxt = List->ListNext ; 4699 4700 // The following CAS() releases the lock and pops the head element. 4701 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4702 continue ; 4703 } 4704 List->OnList = 0 ; 4705 OrderAccess::fence() ; 4706 List->unpark () ; 4707 return ; 4708 } 4709} 4710 4711 4712void Threads::verify() { 4713 ALL_JAVA_THREADS(p) { 4714 p->verify(); 4715 } 4716 VMThread* thread = VMThread::vm_thread(); 4717 if (thread != NULL) thread->verify(); 4718} 4719