thread.cpp revision 9801:80f8be586fae
1/* 2 * Copyright (c) 1997, 2015, 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/codeCache.hpp" 31#include "code/codeCacheExtensions.hpp" 32#include "code/scopeDesc.hpp" 33#include "compiler/compileBroker.hpp" 34#include "gc/shared/gcId.hpp" 35#include "gc/shared/gcLocker.inline.hpp" 36#include "gc/shared/workgroup.hpp" 37#include "interpreter/interpreter.hpp" 38#include "interpreter/linkResolver.hpp" 39#include "interpreter/oopMapCache.hpp" 40#include "jvmtifiles/jvmtiEnv.hpp" 41#include "logging/logConfiguration.hpp" 42#include "memory/metaspaceShared.hpp" 43#include "memory/oopFactory.hpp" 44#include "memory/universe.inline.hpp" 45#include "oops/instanceKlass.hpp" 46#include "oops/objArrayOop.hpp" 47#include "oops/oop.inline.hpp" 48#include "oops/symbol.hpp" 49#include "oops/verifyOopClosure.hpp" 50#include "prims/jvm_misc.hpp" 51#include "prims/jvmtiExport.hpp" 52#include "prims/jvmtiThreadState.hpp" 53#include "prims/privilegedStack.hpp" 54#include "runtime/arguments.hpp" 55#include "runtime/atomic.inline.hpp" 56#include "runtime/biasedLocking.hpp" 57#include "runtime/commandLineFlagConstraintList.hpp" 58#include "runtime/commandLineFlagRangeList.hpp" 59#include "runtime/deoptimization.hpp" 60#include "runtime/fprofiler.hpp" 61#include "runtime/frame.inline.hpp" 62#include "runtime/globals.hpp" 63#include "runtime/init.hpp" 64#include "runtime/interfaceSupport.hpp" 65#include "runtime/java.hpp" 66#include "runtime/javaCalls.hpp" 67#include "runtime/jniPeriodicChecker.hpp" 68#include "runtime/memprofiler.hpp" 69#include "runtime/mutexLocker.hpp" 70#include "runtime/objectMonitor.hpp" 71#include "runtime/orderAccess.inline.hpp" 72#include "runtime/osThread.hpp" 73#include "runtime/safepoint.hpp" 74#include "runtime/sharedRuntime.hpp" 75#include "runtime/statSampler.hpp" 76#include "runtime/stubRoutines.hpp" 77#include "runtime/sweeper.hpp" 78#include "runtime/task.hpp" 79#include "runtime/thread.inline.hpp" 80#include "runtime/threadCritical.hpp" 81#include "runtime/vframe.hpp" 82#include "runtime/vframeArray.hpp" 83#include "runtime/vframe_hp.hpp" 84#include "runtime/vmThread.hpp" 85#include "runtime/vm_operations.hpp" 86#include "runtime/vm_version.hpp" 87#include "services/attachListener.hpp" 88#include "services/management.hpp" 89#include "services/memTracker.hpp" 90#include "services/threadService.hpp" 91#include "trace/traceMacros.hpp" 92#include "trace/tracing.hpp" 93#include "utilities/defaultStream.hpp" 94#include "utilities/dtrace.hpp" 95#include "utilities/events.hpp" 96#include "utilities/macros.hpp" 97#include "utilities/preserveException.hpp" 98#if INCLUDE_ALL_GCS 99#include "gc/cms/concurrentMarkSweepThread.hpp" 100#include "gc/g1/concurrentMarkThread.inline.hpp" 101#include "gc/parallel/pcTasks.hpp" 102#endif // INCLUDE_ALL_GCS 103#if INCLUDE_JVMCI 104#include "jvmci/jvmciCompiler.hpp" 105#include "jvmci/jvmciRuntime.hpp" 106#endif 107#ifdef COMPILER1 108#include "c1/c1_Compiler.hpp" 109#endif 110#ifdef COMPILER2 111#include "opto/c2compiler.hpp" 112#include "opto/idealGraphPrinter.hpp" 113#endif 114#if INCLUDE_RTM_OPT 115#include "runtime/rtmLocking.hpp" 116#endif 117 118#ifdef DTRACE_ENABLED 119 120// Only bother with this argument setup if dtrace is available 121 122 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START 123 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP 124 125 #define DTRACE_THREAD_PROBE(probe, javathread) \ 126 { \ 127 ResourceMark rm(this); \ 128 int len = 0; \ 129 const char* name = (javathread)->get_thread_name(); \ 130 len = strlen(name); \ 131 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \ 132 (char *) name, len, \ 133 java_lang_Thread::thread_id((javathread)->threadObj()), \ 134 (uintptr_t) (javathread)->osthread()->thread_id(), \ 135 java_lang_Thread::is_daemon((javathread)->threadObj())); \ 136 } 137 138#else // ndef DTRACE_ENABLED 139 140 #define DTRACE_THREAD_PROBE(probe, javathread) 141 142#endif // ndef DTRACE_ENABLED 143 144#ifndef USE_LIBRARY_BASED_TLS_ONLY 145// Current thread is maintained as a thread-local variable 146THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL; 147#endif 148 149// Class hierarchy 150// - Thread 151// - VMThread 152// - WatcherThread 153// - ConcurrentMarkSweepThread 154// - JavaThread 155// - CompilerThread 156 157// ======= Thread ======== 158// Support for forcing alignment of thread objects for biased locking 159void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) { 160 if (UseBiasedLocking) { 161 const int alignment = markOopDesc::biased_lock_alignment; 162 size_t aligned_size = size + (alignment - sizeof(intptr_t)); 163 void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC) 164 : AllocateHeap(aligned_size, flags, CURRENT_PC, 165 AllocFailStrategy::RETURN_NULL); 166 void* aligned_addr = (void*) align_size_up((intptr_t) real_malloc_addr, alignment); 167 assert(((uintptr_t) aligned_addr + (uintptr_t) size) <= 168 ((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size), 169 "JavaThread alignment code overflowed allocated storage"); 170 if (TraceBiasedLocking) { 171 if (aligned_addr != real_malloc_addr) { 172 tty->print_cr("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT, 173 p2i(real_malloc_addr), p2i(aligned_addr)); 174 } 175 } 176 ((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr; 177 return aligned_addr; 178 } else { 179 return throw_excpt? AllocateHeap(size, flags, CURRENT_PC) 180 : AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL); 181 } 182} 183 184void Thread::operator delete(void* p) { 185 if (UseBiasedLocking) { 186 void* real_malloc_addr = ((Thread*) p)->_real_malloc_address; 187 FreeHeap(real_malloc_addr); 188 } else { 189 FreeHeap(p); 190 } 191} 192 193 194// Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread, 195// JavaThread 196 197 198Thread::Thread() { 199 // stack and get_thread 200 set_stack_base(NULL); 201 set_stack_size(0); 202 set_self_raw_id(0); 203 set_lgrp_id(-1); 204 DEBUG_ONLY(clear_suspendible_thread();) 205 206 // allocated data structures 207 set_osthread(NULL); 208 set_resource_area(new (mtThread)ResourceArea()); 209 DEBUG_ONLY(_current_resource_mark = NULL;) 210 set_handle_area(new (mtThread) HandleArea(NULL)); 211 set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true)); 212 set_active_handles(NULL); 213 set_free_handle_block(NULL); 214 set_last_handle_mark(NULL); 215 216 // This initial value ==> never claimed. 217 _oops_do_parity = 0; 218 219 // the handle mark links itself to last_handle_mark 220 new HandleMark(this); 221 222 // plain initialization 223 debug_only(_owned_locks = NULL;) 224 debug_only(_allow_allocation_count = 0;) 225 NOT_PRODUCT(_allow_safepoint_count = 0;) 226 NOT_PRODUCT(_skip_gcalot = false;) 227 _jvmti_env_iteration_count = 0; 228 set_allocated_bytes(0); 229 _vm_operation_started_count = 0; 230 _vm_operation_completed_count = 0; 231 _current_pending_monitor = NULL; 232 _current_pending_monitor_is_from_java = true; 233 _current_waiting_monitor = NULL; 234 _num_nested_signal = 0; 235 omFreeList = NULL; 236 omFreeCount = 0; 237 omFreeProvision = 32; 238 omInUseList = NULL; 239 omInUseCount = 0; 240 241#ifdef ASSERT 242 _visited_for_critical_count = false; 243#endif 244 245 _SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true, 246 Monitor::_safepoint_check_sometimes); 247 _suspend_flags = 0; 248 249 // thread-specific hashCode stream generator state - Marsaglia shift-xor form 250 _hashStateX = os::random(); 251 _hashStateY = 842502087; 252 _hashStateZ = 0x8767; // (int)(3579807591LL & 0xffff) ; 253 _hashStateW = 273326509; 254 255 _OnTrap = 0; 256 _schedctl = NULL; 257 _Stalled = 0; 258 _TypeTag = 0x2BAD; 259 260 // Many of the following fields are effectively final - immutable 261 // Note that nascent threads can't use the Native Monitor-Mutex 262 // construct until the _MutexEvent is initialized ... 263 // CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents 264 // we might instead use a stack of ParkEvents that we could provision on-demand. 265 // The stack would act as a cache to avoid calls to ParkEvent::Allocate() 266 // and ::Release() 267 _ParkEvent = ParkEvent::Allocate(this); 268 _SleepEvent = ParkEvent::Allocate(this); 269 _MutexEvent = ParkEvent::Allocate(this); 270 _MuxEvent = ParkEvent::Allocate(this); 271 272#ifdef CHECK_UNHANDLED_OOPS 273 if (CheckUnhandledOops) { 274 _unhandled_oops = new UnhandledOops(this); 275 } 276#endif // CHECK_UNHANDLED_OOPS 277#ifdef ASSERT 278 if (UseBiasedLocking) { 279 assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed"); 280 assert(this == _real_malloc_address || 281 this == (void*) align_size_up((intptr_t) _real_malloc_address, markOopDesc::biased_lock_alignment), 282 "bug in forced alignment of thread objects"); 283 } 284#endif // ASSERT 285} 286 287void Thread::initialize_thread_current() { 288#ifndef USE_LIBRARY_BASED_TLS_ONLY 289 assert(_thr_current == NULL, "Thread::current already initialized"); 290 _thr_current = this; 291#endif 292 assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized"); 293 ThreadLocalStorage::set_thread(this); 294 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 295} 296 297void Thread::clear_thread_current() { 298 assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!"); 299#ifndef USE_LIBRARY_BASED_TLS_ONLY 300 _thr_current = NULL; 301#endif 302 ThreadLocalStorage::set_thread(NULL); 303} 304 305void Thread::record_stack_base_and_size() { 306 set_stack_base(os::current_stack_base()); 307 set_stack_size(os::current_stack_size()); 308 if (is_Java_thread()) { 309 ((JavaThread*) this)->set_stack_overflow_limit(); 310 ((JavaThread*) this)->set_reserved_stack_activation(stack_base()); 311 } 312 // CR 7190089: on Solaris, primordial thread's stack is adjusted 313 // in initialize_thread(). Without the adjustment, stack size is 314 // incorrect if stack is set to unlimited (ulimit -s unlimited). 315 // So far, only Solaris has real implementation of initialize_thread(). 316 // 317 // set up any platform-specific state. 318 os::initialize_thread(this); 319 320#if INCLUDE_NMT 321 // record thread's native stack, stack grows downward 322 address stack_low_addr = stack_base() - stack_size(); 323 MemTracker::record_thread_stack(stack_low_addr, stack_size()); 324#endif // INCLUDE_NMT 325} 326 327 328Thread::~Thread() { 329 // Reclaim the objectmonitors from the omFreeList of the moribund thread. 330 ObjectSynchronizer::omFlush(this); 331 332 EVENT_THREAD_DESTRUCT(this); 333 334 // stack_base can be NULL if the thread is never started or exited before 335 // record_stack_base_and_size called. Although, we would like to ensure 336 // that all started threads do call record_stack_base_and_size(), there is 337 // not proper way to enforce that. 338#if INCLUDE_NMT 339 if (_stack_base != NULL) { 340 address low_stack_addr = stack_base() - stack_size(); 341 MemTracker::release_thread_stack(low_stack_addr, stack_size()); 342#ifdef ASSERT 343 set_stack_base(NULL); 344#endif 345 } 346#endif // INCLUDE_NMT 347 348 // deallocate data structures 349 delete resource_area(); 350 // since the handle marks are using the handle area, we have to deallocated the root 351 // handle mark before deallocating the thread's handle area, 352 assert(last_handle_mark() != NULL, "check we have an element"); 353 delete last_handle_mark(); 354 assert(last_handle_mark() == NULL, "check we have reached the end"); 355 356 // It's possible we can encounter a null _ParkEvent, etc., in stillborn threads. 357 // We NULL out the fields for good hygiene. 358 ParkEvent::Release(_ParkEvent); _ParkEvent = NULL; 359 ParkEvent::Release(_SleepEvent); _SleepEvent = NULL; 360 ParkEvent::Release(_MutexEvent); _MutexEvent = NULL; 361 ParkEvent::Release(_MuxEvent); _MuxEvent = NULL; 362 363 delete handle_area(); 364 delete metadata_handles(); 365 366 // osthread() can be NULL, if creation of thread failed. 367 if (osthread() != NULL) os::free_thread(osthread()); 368 369 delete _SR_lock; 370 371 // clear Thread::current if thread is deleting itself. 372 // Needed to ensure JNI correctly detects non-attached threads. 373 if (this == Thread::current()) { 374 clear_thread_current(); 375 } 376 377 CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();) 378} 379 380// NOTE: dummy function for assertion purpose. 381void Thread::run() { 382 ShouldNotReachHere(); 383} 384 385#ifdef ASSERT 386// Private method to check for dangling thread pointer 387void check_for_dangling_thread_pointer(Thread *thread) { 388 assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(), 389 "possibility of dangling Thread pointer"); 390} 391#endif 392 393ThreadPriority Thread::get_priority(const Thread* const thread) { 394 ThreadPriority priority; 395 // Can return an error! 396 (void)os::get_priority(thread, priority); 397 assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found"); 398 return priority; 399} 400 401void Thread::set_priority(Thread* thread, ThreadPriority priority) { 402 debug_only(check_for_dangling_thread_pointer(thread);) 403 // Can return an error! 404 (void)os::set_priority(thread, priority); 405} 406 407 408void Thread::start(Thread* thread) { 409 // Start is different from resume in that its safety is guaranteed by context or 410 // being called from a Java method synchronized on the Thread object. 411 if (!DisableStartThread) { 412 if (thread->is_Java_thread()) { 413 // Initialize the thread state to RUNNABLE before starting this thread. 414 // Can not set it after the thread started because we do not know the 415 // exact thread state at that time. It could be in MONITOR_WAIT or 416 // in SLEEPING or some other state. 417 java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(), 418 java_lang_Thread::RUNNABLE); 419 } 420 os::start_thread(thread); 421 } 422} 423 424// Enqueue a VM_Operation to do the job for us - sometime later 425void Thread::send_async_exception(oop java_thread, oop java_throwable) { 426 VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable); 427 VMThread::execute(vm_stop); 428} 429 430 431// Check if an external suspend request has completed (or has been 432// cancelled). Returns true if the thread is externally suspended and 433// false otherwise. 434// 435// The bits parameter returns information about the code path through 436// the routine. Useful for debugging: 437// 438// set in is_ext_suspend_completed(): 439// 0x00000001 - routine was entered 440// 0x00000010 - routine return false at end 441// 0x00000100 - thread exited (return false) 442// 0x00000200 - suspend request cancelled (return false) 443// 0x00000400 - thread suspended (return true) 444// 0x00001000 - thread is in a suspend equivalent state (return true) 445// 0x00002000 - thread is native and walkable (return true) 446// 0x00004000 - thread is native_trans and walkable (needed retry) 447// 448// set in wait_for_ext_suspend_completion(): 449// 0x00010000 - routine was entered 450// 0x00020000 - suspend request cancelled before loop (return false) 451// 0x00040000 - thread suspended before loop (return true) 452// 0x00080000 - suspend request cancelled in loop (return false) 453// 0x00100000 - thread suspended in loop (return true) 454// 0x00200000 - suspend not completed during retry loop (return false) 455 456// Helper class for tracing suspend wait debug bits. 457// 458// 0x00000100 indicates that the target thread exited before it could 459// self-suspend which is not a wait failure. 0x00000200, 0x00020000 and 460// 0x00080000 each indicate a cancelled suspend request so they don't 461// count as wait failures either. 462#define DEBUG_FALSE_BITS (0x00000010 | 0x00200000) 463 464class TraceSuspendDebugBits : public StackObj { 465 private: 466 JavaThread * jt; 467 bool is_wait; 468 bool called_by_wait; // meaningful when !is_wait 469 uint32_t * bits; 470 471 public: 472 TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait, 473 uint32_t *_bits) { 474 jt = _jt; 475 is_wait = _is_wait; 476 called_by_wait = _called_by_wait; 477 bits = _bits; 478 } 479 480 ~TraceSuspendDebugBits() { 481 if (!is_wait) { 482#if 1 483 // By default, don't trace bits for is_ext_suspend_completed() calls. 484 // That trace is very chatty. 485 return; 486#else 487 if (!called_by_wait) { 488 // If tracing for is_ext_suspend_completed() is enabled, then only 489 // trace calls to it from wait_for_ext_suspend_completion() 490 return; 491 } 492#endif 493 } 494 495 if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) { 496 if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) { 497 MutexLocker ml(Threads_lock); // needed for get_thread_name() 498 ResourceMark rm; 499 500 tty->print_cr( 501 "Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)", 502 jt->get_thread_name(), *bits); 503 504 guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed"); 505 } 506 } 507 } 508}; 509#undef DEBUG_FALSE_BITS 510 511 512bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay, 513 uint32_t *bits) { 514 TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits); 515 516 bool did_trans_retry = false; // only do thread_in_native_trans retry once 517 bool do_trans_retry; // flag to force the retry 518 519 *bits |= 0x00000001; 520 521 do { 522 do_trans_retry = false; 523 524 if (is_exiting()) { 525 // Thread is in the process of exiting. This is always checked 526 // first to reduce the risk of dereferencing a freed JavaThread. 527 *bits |= 0x00000100; 528 return false; 529 } 530 531 if (!is_external_suspend()) { 532 // Suspend request is cancelled. This is always checked before 533 // is_ext_suspended() to reduce the risk of a rogue resume 534 // confusing the thread that made the suspend request. 535 *bits |= 0x00000200; 536 return false; 537 } 538 539 if (is_ext_suspended()) { 540 // thread is suspended 541 *bits |= 0x00000400; 542 return true; 543 } 544 545 // Now that we no longer do hard suspends of threads running 546 // native code, the target thread can be changing thread state 547 // while we are in this routine: 548 // 549 // _thread_in_native -> _thread_in_native_trans -> _thread_blocked 550 // 551 // We save a copy of the thread state as observed at this moment 552 // and make our decision about suspend completeness based on the 553 // copy. This closes the race where the thread state is seen as 554 // _thread_in_native_trans in the if-thread_blocked check, but is 555 // seen as _thread_blocked in if-thread_in_native_trans check. 556 JavaThreadState save_state = thread_state(); 557 558 if (save_state == _thread_blocked && is_suspend_equivalent()) { 559 // If the thread's state is _thread_blocked and this blocking 560 // condition is known to be equivalent to a suspend, then we can 561 // consider the thread to be externally suspended. This means that 562 // the code that sets _thread_blocked has been modified to do 563 // self-suspension if the blocking condition releases. We also 564 // used to check for CONDVAR_WAIT here, but that is now covered by 565 // the _thread_blocked with self-suspension check. 566 // 567 // Return true since we wouldn't be here unless there was still an 568 // external suspend request. 569 *bits |= 0x00001000; 570 return true; 571 } else if (save_state == _thread_in_native && frame_anchor()->walkable()) { 572 // Threads running native code will self-suspend on native==>VM/Java 573 // transitions. If its stack is walkable (should always be the case 574 // unless this function is called before the actual java_suspend() 575 // call), then the wait is done. 576 *bits |= 0x00002000; 577 return true; 578 } else if (!called_by_wait && !did_trans_retry && 579 save_state == _thread_in_native_trans && 580 frame_anchor()->walkable()) { 581 // The thread is transitioning from thread_in_native to another 582 // thread state. check_safepoint_and_suspend_for_native_trans() 583 // will force the thread to self-suspend. If it hasn't gotten 584 // there yet we may have caught the thread in-between the native 585 // code check above and the self-suspend. Lucky us. If we were 586 // called by wait_for_ext_suspend_completion(), then it 587 // will be doing the retries so we don't have to. 588 // 589 // Since we use the saved thread state in the if-statement above, 590 // there is a chance that the thread has already transitioned to 591 // _thread_blocked by the time we get here. In that case, we will 592 // make a single unnecessary pass through the logic below. This 593 // doesn't hurt anything since we still do the trans retry. 594 595 *bits |= 0x00004000; 596 597 // Once the thread leaves thread_in_native_trans for another 598 // thread state, we break out of this retry loop. We shouldn't 599 // need this flag to prevent us from getting back here, but 600 // sometimes paranoia is good. 601 did_trans_retry = true; 602 603 // We wait for the thread to transition to a more usable state. 604 for (int i = 1; i <= SuspendRetryCount; i++) { 605 // We used to do an "os::yield_all(i)" call here with the intention 606 // that yielding would increase on each retry. However, the parameter 607 // is ignored on Linux which means the yield didn't scale up. Waiting 608 // on the SR_lock below provides a much more predictable scale up for 609 // the delay. It also provides a simple/direct point to check for any 610 // safepoint requests from the VMThread 611 612 // temporarily drops SR_lock while doing wait with safepoint check 613 // (if we're a JavaThread - the WatcherThread can also call this) 614 // and increase delay with each retry 615 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 616 617 // check the actual thread state instead of what we saved above 618 if (thread_state() != _thread_in_native_trans) { 619 // the thread has transitioned to another thread state so 620 // try all the checks (except this one) one more time. 621 do_trans_retry = true; 622 break; 623 } 624 } // end retry loop 625 626 627 } 628 } while (do_trans_retry); 629 630 *bits |= 0x00000010; 631 return false; 632} 633 634// Wait for an external suspend request to complete (or be cancelled). 635// Returns true if the thread is externally suspended and false otherwise. 636// 637bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay, 638 uint32_t *bits) { 639 TraceSuspendDebugBits tsdb(this, true /* is_wait */, 640 false /* !called_by_wait */, bits); 641 642 // local flag copies to minimize SR_lock hold time 643 bool is_suspended; 644 bool pending; 645 uint32_t reset_bits; 646 647 // set a marker so is_ext_suspend_completed() knows we are the caller 648 *bits |= 0x00010000; 649 650 // We use reset_bits to reinitialize the bits value at the top of 651 // each retry loop. This allows the caller to make use of any 652 // unused bits for their own marking purposes. 653 reset_bits = *bits; 654 655 { 656 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 657 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 658 delay, bits); 659 pending = is_external_suspend(); 660 } 661 // must release SR_lock to allow suspension to complete 662 663 if (!pending) { 664 // A cancelled suspend request is the only false return from 665 // is_ext_suspend_completed() that keeps us from entering the 666 // retry loop. 667 *bits |= 0x00020000; 668 return false; 669 } 670 671 if (is_suspended) { 672 *bits |= 0x00040000; 673 return true; 674 } 675 676 for (int i = 1; i <= retries; i++) { 677 *bits = reset_bits; // reinit to only track last retry 678 679 // We used to do an "os::yield_all(i)" call here with the intention 680 // that yielding would increase on each retry. However, the parameter 681 // is ignored on Linux which means the yield didn't scale up. Waiting 682 // on the SR_lock below provides a much more predictable scale up for 683 // the delay. It also provides a simple/direct point to check for any 684 // safepoint requests from the VMThread 685 686 { 687 MutexLocker ml(SR_lock()); 688 // wait with safepoint check (if we're a JavaThread - the WatcherThread 689 // can also call this) and increase delay with each retry 690 SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay); 691 692 is_suspended = is_ext_suspend_completed(true /* called_by_wait */, 693 delay, bits); 694 695 // It is possible for the external suspend request to be cancelled 696 // (by a resume) before the actual suspend operation is completed. 697 // Refresh our local copy to see if we still need to wait. 698 pending = is_external_suspend(); 699 } 700 701 if (!pending) { 702 // A cancelled suspend request is the only false return from 703 // is_ext_suspend_completed() that keeps us from staying in the 704 // retry loop. 705 *bits |= 0x00080000; 706 return false; 707 } 708 709 if (is_suspended) { 710 *bits |= 0x00100000; 711 return true; 712 } 713 } // end retry loop 714 715 // thread did not suspend after all our retries 716 *bits |= 0x00200000; 717 return false; 718} 719 720#ifndef PRODUCT 721void JavaThread::record_jump(address target, address instr, const char* file, 722 int line) { 723 724 // This should not need to be atomic as the only way for simultaneous 725 // updates is via interrupts. Even then this should be rare or non-existent 726 // and we don't care that much anyway. 727 728 int index = _jmp_ring_index; 729 _jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1); 730 _jmp_ring[index]._target = (intptr_t) target; 731 _jmp_ring[index]._instruction = (intptr_t) instr; 732 _jmp_ring[index]._file = file; 733 _jmp_ring[index]._line = line; 734} 735#endif // PRODUCT 736 737// Called by flat profiler 738// Callers have already called wait_for_ext_suspend_completion 739// The assertion for that is currently too complex to put here: 740bool JavaThread::profile_last_Java_frame(frame* _fr) { 741 bool gotframe = false; 742 // self suspension saves needed state. 743 if (has_last_Java_frame() && _anchor.walkable()) { 744 *_fr = pd_last_frame(); 745 gotframe = true; 746 } 747 return gotframe; 748} 749 750void Thread::interrupt(Thread* thread) { 751 debug_only(check_for_dangling_thread_pointer(thread);) 752 os::interrupt(thread); 753} 754 755bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) { 756 debug_only(check_for_dangling_thread_pointer(thread);) 757 // Note: If clear_interrupted==false, this simply fetches and 758 // returns the value of the field osthread()->interrupted(). 759 return os::is_interrupted(thread, clear_interrupted); 760} 761 762 763// GC Support 764bool Thread::claim_oops_do_par_case(int strong_roots_parity) { 765 jint thread_parity = _oops_do_parity; 766 if (thread_parity != strong_roots_parity) { 767 jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity); 768 if (res == thread_parity) { 769 return true; 770 } else { 771 guarantee(res == strong_roots_parity, "Or else what?"); 772 return false; 773 } 774 } 775 return false; 776} 777 778void Thread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 779 active_handles()->oops_do(f); 780 // Do oop for ThreadShadow 781 f->do_oop((oop*)&_pending_exception); 782 handle_area()->oops_do(f); 783} 784 785void Thread::nmethods_do(CodeBlobClosure* cf) { 786 // no nmethods in a generic thread... 787} 788 789void Thread::metadata_handles_do(void f(Metadata*)) { 790 // Only walk the Handles in Thread. 791 if (metadata_handles() != NULL) { 792 for (int i = 0; i< metadata_handles()->length(); i++) { 793 f(metadata_handles()->at(i)); 794 } 795 } 796} 797 798void Thread::print_on(outputStream* st) const { 799 // get_priority assumes osthread initialized 800 if (osthread() != NULL) { 801 int os_prio; 802 if (os::get_native_priority(this, &os_prio) == OS_OK) { 803 st->print("os_prio=%d ", os_prio); 804 } 805 st->print("tid=" INTPTR_FORMAT " ", p2i(this)); 806 ext().print_on(st); 807 osthread()->print_on(st); 808 } 809 debug_only(if (WizardMode) print_owned_locks_on(st);) 810} 811 812// Thread::print_on_error() is called by fatal error handler. Don't use 813// any lock or allocate memory. 814void Thread::print_on_error(outputStream* st, char* buf, int buflen) const { 815 if (is_VM_thread()) st->print("VMThread"); 816 else if (is_Compiler_thread()) st->print("CompilerThread"); 817 else if (is_Java_thread()) st->print("JavaThread"); 818 else if (is_GC_task_thread()) st->print("GCTaskThread"); 819 else if (is_Watcher_thread()) st->print("WatcherThread"); 820 else if (is_ConcurrentGC_thread()) st->print("ConcurrentGCThread"); 821 else st->print("Thread"); 822 823 st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]", 824 p2i(_stack_base - _stack_size), p2i(_stack_base)); 825 826 if (osthread()) { 827 st->print(" [id=%d]", osthread()->thread_id()); 828 } 829} 830 831#ifdef ASSERT 832void Thread::print_owned_locks_on(outputStream* st) const { 833 Monitor *cur = _owned_locks; 834 if (cur == NULL) { 835 st->print(" (no locks) "); 836 } else { 837 st->print_cr(" Locks owned:"); 838 while (cur) { 839 cur->print_on(st); 840 cur = cur->next(); 841 } 842 } 843} 844 845static int ref_use_count = 0; 846 847bool Thread::owns_locks_but_compiled_lock() const { 848 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 849 if (cur != Compile_lock) return true; 850 } 851 return false; 852} 853 854 855#endif 856 857#ifndef PRODUCT 858 859// The flag: potential_vm_operation notifies if this particular safepoint state could potential 860// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that 861// no threads which allow_vm_block's are held 862void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) { 863 // Check if current thread is allowed to block at a safepoint 864 if (!(_allow_safepoint_count == 0)) { 865 fatal("Possible safepoint reached by thread that does not allow it"); 866 } 867 if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) { 868 fatal("LEAF method calling lock?"); 869 } 870 871#ifdef ASSERT 872 if (potential_vm_operation && is_Java_thread() 873 && !Universe::is_bootstrapping()) { 874 // Make sure we do not hold any locks that the VM thread also uses. 875 // This could potentially lead to deadlocks 876 for (Monitor *cur = _owned_locks; cur; cur = cur->next()) { 877 // Threads_lock is special, since the safepoint synchronization will not start before this is 878 // acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock, 879 // since it is used to transfer control between JavaThreads and the VMThread 880 // Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first! 881 if ((cur->allow_vm_block() && 882 cur != Threads_lock && 883 cur != Compile_lock && // Temporary: should not be necessary when we get separate compilation 884 cur != VMOperationRequest_lock && 885 cur != VMOperationQueue_lock) || 886 cur->rank() == Mutex::special) { 887 fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name()); 888 } 889 } 890 } 891 892 if (GCALotAtAllSafepoints) { 893 // We could enter a safepoint here and thus have a gc 894 InterfaceSupport::check_gc_alot(); 895 } 896#endif 897} 898#endif 899 900bool Thread::is_in_stack(address adr) const { 901 assert(Thread::current() == this, "is_in_stack can only be called from current thread"); 902 address end = os::current_stack_pointer(); 903 // Allow non Java threads to call this without stack_base 904 if (_stack_base == NULL) return true; 905 if (stack_base() >= adr && adr >= end) return true; 906 907 return false; 908} 909 910 911bool Thread::is_in_usable_stack(address adr) const { 912 size_t stack_guard_size = os::uses_stack_guard_pages() ? (StackReservedPages + StackYellowPages + StackRedPages) * os::vm_page_size() : 0; 913 size_t usable_stack_size = _stack_size - stack_guard_size; 914 915 return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size)); 916} 917 918 919// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter 920// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being 921// used for compilation in the future. If that change is made, the need for these methods 922// should be revisited, and they should be removed if possible. 923 924bool Thread::is_lock_owned(address adr) const { 925 return on_local_stack(adr); 926} 927 928bool Thread::set_as_starting_thread() { 929 // NOTE: this must be called inside the main thread. 930 return os::create_main_thread((JavaThread*)this); 931} 932 933static void initialize_class(Symbol* class_name, TRAPS) { 934 Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK); 935 InstanceKlass::cast(klass)->initialize(CHECK); 936} 937 938 939// Creates the initial ThreadGroup 940static Handle create_initial_thread_group(TRAPS) { 941 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH); 942 instanceKlassHandle klass (THREAD, k); 943 944 Handle system_instance = klass->allocate_instance_handle(CHECK_NH); 945 { 946 JavaValue result(T_VOID); 947 JavaCalls::call_special(&result, 948 system_instance, 949 klass, 950 vmSymbols::object_initializer_name(), 951 vmSymbols::void_method_signature(), 952 CHECK_NH); 953 } 954 Universe::set_system_thread_group(system_instance()); 955 956 Handle main_instance = klass->allocate_instance_handle(CHECK_NH); 957 { 958 JavaValue result(T_VOID); 959 Handle string = java_lang_String::create_from_str("main", CHECK_NH); 960 JavaCalls::call_special(&result, 961 main_instance, 962 klass, 963 vmSymbols::object_initializer_name(), 964 vmSymbols::threadgroup_string_void_signature(), 965 system_instance, 966 string, 967 CHECK_NH); 968 } 969 return main_instance; 970} 971 972// Creates the initial Thread 973static oop create_initial_thread(Handle thread_group, JavaThread* thread, 974 TRAPS) { 975 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL); 976 instanceKlassHandle klass (THREAD, k); 977 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK_NULL); 978 979 java_lang_Thread::set_thread(thread_oop(), thread); 980 java_lang_Thread::set_priority(thread_oop(), NormPriority); 981 thread->set_threadObj(thread_oop()); 982 983 Handle string = java_lang_String::create_from_str("main", CHECK_NULL); 984 985 JavaValue result(T_VOID); 986 JavaCalls::call_special(&result, thread_oop, 987 klass, 988 vmSymbols::object_initializer_name(), 989 vmSymbols::threadgroup_string_void_signature(), 990 thread_group, 991 string, 992 CHECK_NULL); 993 return thread_oop(); 994} 995 996static void call_initializeSystemClass(TRAPS) { 997 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 998 instanceKlassHandle klass (THREAD, k); 999 1000 JavaValue result(T_VOID); 1001 JavaCalls::call_static(&result, klass, vmSymbols::initializeSystemClass_name(), 1002 vmSymbols::void_method_signature(), CHECK); 1003} 1004 1005char java_runtime_name[128] = ""; 1006char java_runtime_version[128] = ""; 1007 1008// extract the JRE name from sun.misc.Version.java_runtime_name 1009static const char* get_java_runtime_name(TRAPS) { 1010 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1011 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1012 fieldDescriptor fd; 1013 bool found = k != NULL && 1014 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(), 1015 vmSymbols::string_signature(), &fd); 1016 if (found) { 1017 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1018 if (name_oop == NULL) { 1019 return NULL; 1020 } 1021 const char* name = java_lang_String::as_utf8_string(name_oop, 1022 java_runtime_name, 1023 sizeof(java_runtime_name)); 1024 return name; 1025 } else { 1026 return NULL; 1027 } 1028} 1029 1030// extract the JRE version from sun.misc.Version.java_runtime_version 1031static const char* get_java_runtime_version(TRAPS) { 1032 Klass* k = SystemDictionary::find(vmSymbols::sun_misc_Version(), 1033 Handle(), Handle(), CHECK_AND_CLEAR_NULL); 1034 fieldDescriptor fd; 1035 bool found = k != NULL && 1036 InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(), 1037 vmSymbols::string_signature(), &fd); 1038 if (found) { 1039 oop name_oop = k->java_mirror()->obj_field(fd.offset()); 1040 if (name_oop == NULL) { 1041 return NULL; 1042 } 1043 const char* name = java_lang_String::as_utf8_string(name_oop, 1044 java_runtime_version, 1045 sizeof(java_runtime_version)); 1046 return name; 1047 } else { 1048 return NULL; 1049 } 1050} 1051 1052// General purpose hook into Java code, run once when the VM is initialized. 1053// The Java library method itself may be changed independently from the VM. 1054static void call_postVMInitHook(TRAPS) { 1055 Klass* k = SystemDictionary::resolve_or_null(vmSymbols::sun_misc_PostVMInitHook(), THREAD); 1056 instanceKlassHandle klass (THREAD, k); 1057 if (klass.not_null()) { 1058 JavaValue result(T_VOID); 1059 JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(), 1060 vmSymbols::void_method_signature(), 1061 CHECK); 1062 } 1063} 1064 1065static void reset_vm_info_property(TRAPS) { 1066 // the vm info string 1067 ResourceMark rm(THREAD); 1068 const char *vm_info = VM_Version::vm_info_string(); 1069 1070 // java.lang.System class 1071 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK); 1072 instanceKlassHandle klass (THREAD, k); 1073 1074 // setProperty arguments 1075 Handle key_str = java_lang_String::create_from_str("java.vm.info", CHECK); 1076 Handle value_str = java_lang_String::create_from_str(vm_info, CHECK); 1077 1078 // return value 1079 JavaValue r(T_OBJECT); 1080 1081 // public static String setProperty(String key, String value); 1082 JavaCalls::call_static(&r, 1083 klass, 1084 vmSymbols::setProperty_name(), 1085 vmSymbols::string_string_string_signature(), 1086 key_str, 1087 value_str, 1088 CHECK); 1089} 1090 1091 1092void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name, 1093 bool daemon, TRAPS) { 1094 assert(thread_group.not_null(), "thread group should be specified"); 1095 assert(threadObj() == NULL, "should only create Java thread object once"); 1096 1097 Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK); 1098 instanceKlassHandle klass (THREAD, k); 1099 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); 1100 1101 java_lang_Thread::set_thread(thread_oop(), this); 1102 java_lang_Thread::set_priority(thread_oop(), NormPriority); 1103 set_threadObj(thread_oop()); 1104 1105 JavaValue result(T_VOID); 1106 if (thread_name != NULL) { 1107 Handle name = java_lang_String::create_from_str(thread_name, CHECK); 1108 // Thread gets assigned specified name and null target 1109 JavaCalls::call_special(&result, 1110 thread_oop, 1111 klass, 1112 vmSymbols::object_initializer_name(), 1113 vmSymbols::threadgroup_string_void_signature(), 1114 thread_group, // Argument 1 1115 name, // Argument 2 1116 THREAD); 1117 } else { 1118 // Thread gets assigned name "Thread-nnn" and null target 1119 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument) 1120 JavaCalls::call_special(&result, 1121 thread_oop, 1122 klass, 1123 vmSymbols::object_initializer_name(), 1124 vmSymbols::threadgroup_runnable_void_signature(), 1125 thread_group, // Argument 1 1126 Handle(), // Argument 2 1127 THREAD); 1128 } 1129 1130 1131 if (daemon) { 1132 java_lang_Thread::set_daemon(thread_oop()); 1133 } 1134 1135 if (HAS_PENDING_EXCEPTION) { 1136 return; 1137 } 1138 1139 KlassHandle group(THREAD, SystemDictionary::ThreadGroup_klass()); 1140 Handle threadObj(THREAD, this->threadObj()); 1141 1142 JavaCalls::call_special(&result, 1143 thread_group, 1144 group, 1145 vmSymbols::add_method_name(), 1146 vmSymbols::thread_void_signature(), 1147 threadObj, // Arg 1 1148 THREAD); 1149} 1150 1151// NamedThread -- non-JavaThread subclasses with multiple 1152// uniquely named instances should derive from this. 1153NamedThread::NamedThread() : Thread() { 1154 _name = NULL; 1155 _processed_thread = NULL; 1156 _gc_id = GCId::undefined(); 1157} 1158 1159NamedThread::~NamedThread() { 1160 if (_name != NULL) { 1161 FREE_C_HEAP_ARRAY(char, _name); 1162 _name = NULL; 1163 } 1164} 1165 1166void NamedThread::set_name(const char* format, ...) { 1167 guarantee(_name == NULL, "Only get to set name once."); 1168 _name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread); 1169 guarantee(_name != NULL, "alloc failure"); 1170 va_list ap; 1171 va_start(ap, format); 1172 jio_vsnprintf(_name, max_name_len, format, ap); 1173 va_end(ap); 1174} 1175 1176void NamedThread::initialize_named_thread() { 1177 set_native_thread_name(name()); 1178} 1179 1180void NamedThread::print_on(outputStream* st) const { 1181 st->print("\"%s\" ", name()); 1182 Thread::print_on(st); 1183 st->cr(); 1184} 1185 1186 1187// ======= WatcherThread ======== 1188 1189// The watcher thread exists to simulate timer interrupts. It should 1190// be replaced by an abstraction over whatever native support for 1191// timer interrupts exists on the platform. 1192 1193WatcherThread* WatcherThread::_watcher_thread = NULL; 1194bool WatcherThread::_startable = false; 1195volatile bool WatcherThread::_should_terminate = false; 1196 1197WatcherThread::WatcherThread() : Thread(), _crash_protection(NULL) { 1198 assert(watcher_thread() == NULL, "we can only allocate one WatcherThread"); 1199 if (os::create_thread(this, os::watcher_thread)) { 1200 _watcher_thread = this; 1201 1202 // Set the watcher thread to the highest OS priority which should not be 1203 // used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY 1204 // is created. The only normal thread using this priority is the reference 1205 // handler thread, which runs for very short intervals only. 1206 // If the VMThread's priority is not lower than the WatcherThread profiling 1207 // will be inaccurate. 1208 os::set_priority(this, MaxPriority); 1209 if (!DisableStartThread) { 1210 os::start_thread(this); 1211 } 1212 } 1213} 1214 1215int WatcherThread::sleep() const { 1216 // The WatcherThread does not participate in the safepoint protocol 1217 // for the PeriodicTask_lock because it is not a JavaThread. 1218 MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag); 1219 1220 if (_should_terminate) { 1221 // check for termination before we do any housekeeping or wait 1222 return 0; // we did not sleep. 1223 } 1224 1225 // remaining will be zero if there are no tasks, 1226 // causing the WatcherThread to sleep until a task is 1227 // enrolled 1228 int remaining = PeriodicTask::time_to_wait(); 1229 int time_slept = 0; 1230 1231 // we expect this to timeout - we only ever get unparked when 1232 // we should terminate or when a new task has been enrolled 1233 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */); 1234 1235 jlong time_before_loop = os::javaTimeNanos(); 1236 1237 while (true) { 1238 bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag, 1239 remaining); 1240 jlong now = os::javaTimeNanos(); 1241 1242 if (remaining == 0) { 1243 // if we didn't have any tasks we could have waited for a long time 1244 // consider the time_slept zero and reset time_before_loop 1245 time_slept = 0; 1246 time_before_loop = now; 1247 } else { 1248 // need to recalculate since we might have new tasks in _tasks 1249 time_slept = (int) ((now - time_before_loop) / 1000000); 1250 } 1251 1252 // Change to task list or spurious wakeup of some kind 1253 if (timedout || _should_terminate) { 1254 break; 1255 } 1256 1257 remaining = PeriodicTask::time_to_wait(); 1258 if (remaining == 0) { 1259 // Last task was just disenrolled so loop around and wait until 1260 // another task gets enrolled 1261 continue; 1262 } 1263 1264 remaining -= time_slept; 1265 if (remaining <= 0) { 1266 break; 1267 } 1268 } 1269 1270 return time_slept; 1271} 1272 1273void WatcherThread::run() { 1274 assert(this == watcher_thread(), "just checking"); 1275 1276 this->record_stack_base_and_size(); 1277 this->set_native_thread_name(this->name()); 1278 this->set_active_handles(JNIHandleBlock::allocate_block()); 1279 while (true) { 1280 assert(watcher_thread() == Thread::current(), "thread consistency check"); 1281 assert(watcher_thread() == this, "thread consistency check"); 1282 1283 // Calculate how long it'll be until the next PeriodicTask work 1284 // should be done, and sleep that amount of time. 1285 int time_waited = sleep(); 1286 1287 if (is_error_reported()) { 1288 // A fatal error has happened, the error handler(VMError::report_and_die) 1289 // should abort JVM after creating an error log file. However in some 1290 // rare cases, the error handler itself might deadlock. Here we try to 1291 // kill JVM if the fatal error handler fails to abort in 2 minutes. 1292 // 1293 // This code is in WatcherThread because WatcherThread wakes up 1294 // periodically so the fatal error handler doesn't need to do anything; 1295 // also because the WatcherThread is less likely to crash than other 1296 // threads. 1297 1298 for (;;) { 1299 if (!ShowMessageBoxOnError 1300 && (OnError == NULL || OnError[0] == '\0') 1301 && Arguments::abort_hook() == NULL) { 1302 os::sleep(this, (jlong)ErrorLogTimeout * 1000, false); // in seconds 1303 fdStream err(defaultStream::output_fd()); 1304 err.print_raw_cr("# [ timer expired, abort... ]"); 1305 // skip atexit/vm_exit/vm_abort hooks 1306 os::die(); 1307 } 1308 1309 // Wake up 5 seconds later, the fatal handler may reset OnError or 1310 // ShowMessageBoxOnError when it is ready to abort. 1311 os::sleep(this, 5 * 1000, false); 1312 } 1313 } 1314 1315 if (_should_terminate) { 1316 // check for termination before posting the next tick 1317 break; 1318 } 1319 1320 PeriodicTask::real_time_tick(time_waited); 1321 } 1322 1323 // Signal that it is terminated 1324 { 1325 MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag); 1326 _watcher_thread = NULL; 1327 Terminator_lock->notify(); 1328 } 1329} 1330 1331void WatcherThread::start() { 1332 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1333 1334 if (watcher_thread() == NULL && _startable) { 1335 _should_terminate = false; 1336 // Create the single instance of WatcherThread 1337 new WatcherThread(); 1338 } 1339} 1340 1341void WatcherThread::make_startable() { 1342 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1343 _startable = true; 1344} 1345 1346void WatcherThread::stop() { 1347 { 1348 // Follow normal safepoint aware lock enter protocol since the 1349 // WatcherThread is stopped by another JavaThread. 1350 MutexLocker ml(PeriodicTask_lock); 1351 _should_terminate = true; 1352 1353 WatcherThread* watcher = watcher_thread(); 1354 if (watcher != NULL) { 1355 // unpark the WatcherThread so it can see that it should terminate 1356 watcher->unpark(); 1357 } 1358 } 1359 1360 MutexLocker mu(Terminator_lock); 1361 1362 while (watcher_thread() != NULL) { 1363 // This wait should make safepoint checks, wait without a timeout, 1364 // and wait as a suspend-equivalent condition. 1365 // 1366 // Note: If the FlatProfiler is running, then this thread is waiting 1367 // for the WatcherThread to terminate and the WatcherThread, via the 1368 // FlatProfiler task, is waiting for the external suspend request on 1369 // this thread to complete. wait_for_ext_suspend_completion() will 1370 // eventually timeout, but that takes time. Making this wait a 1371 // suspend-equivalent condition solves that timeout problem. 1372 // 1373 Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 1374 Mutex::_as_suspend_equivalent_flag); 1375 } 1376} 1377 1378void WatcherThread::unpark() { 1379 assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required"); 1380 PeriodicTask_lock->notify(); 1381} 1382 1383void WatcherThread::print_on(outputStream* st) const { 1384 st->print("\"%s\" ", name()); 1385 Thread::print_on(st); 1386 st->cr(); 1387} 1388 1389// ======= JavaThread ======== 1390 1391#if INCLUDE_JVMCI 1392 1393jlong* JavaThread::_jvmci_old_thread_counters; 1394 1395bool jvmci_counters_include(JavaThread* thread) { 1396 oop threadObj = thread->threadObj(); 1397 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread(); 1398} 1399 1400void JavaThread::collect_counters(typeArrayOop array) { 1401 if (JVMCICounterSize > 0) { 1402 MutexLocker tl(Threads_lock); 1403 for (int i = 0; i < array->length(); i++) { 1404 array->long_at_put(i, _jvmci_old_thread_counters[i]); 1405 } 1406 for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) { 1407 if (jvmci_counters_include(tp)) { 1408 for (int i = 0; i < array->length(); i++) { 1409 array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]); 1410 } 1411 } 1412 } 1413 } 1414} 1415 1416#endif // INCLUDE_JVMCI 1417 1418// A JavaThread is a normal Java thread 1419 1420void JavaThread::initialize() { 1421 // Initialize fields 1422 1423 // Set the claimed par_id to UINT_MAX (ie not claiming any par_ids) 1424 set_claimed_par_id(UINT_MAX); 1425 1426 set_saved_exception_pc(NULL); 1427 set_threadObj(NULL); 1428 _anchor.clear(); 1429 set_entry_point(NULL); 1430 set_jni_functions(jni_functions()); 1431 set_callee_target(NULL); 1432 set_vm_result(NULL); 1433 set_vm_result_2(NULL); 1434 set_vframe_array_head(NULL); 1435 set_vframe_array_last(NULL); 1436 set_deferred_locals(NULL); 1437 set_deopt_mark(NULL); 1438 set_deopt_nmethod(NULL); 1439 clear_must_deopt_id(); 1440 set_monitor_chunks(NULL); 1441 set_next(NULL); 1442 set_thread_state(_thread_new); 1443 _terminated = _not_terminated; 1444 _privileged_stack_top = NULL; 1445 _array_for_gc = NULL; 1446 _suspend_equivalent = false; 1447 _in_deopt_handler = 0; 1448 _doing_unsafe_access = false; 1449 _stack_guard_state = stack_guard_unused; 1450#if INCLUDE_JVMCI 1451 _pending_monitorenter = false; 1452 _pending_deoptimization = -1; 1453 _pending_failed_speculation = NULL; 1454 _pending_transfer_to_interpreter = false; 1455 _jvmci._alternate_call_target = NULL; 1456 assert(_jvmci._implicit_exception_pc == NULL, "must be"); 1457 if (JVMCICounterSize > 0) { 1458 _jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 1459 memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize); 1460 } else { 1461 _jvmci_counters = NULL; 1462 } 1463#endif // INCLUDE_JVMCI 1464 _reserved_stack_activation = NULL; // stack base not known yet 1465 (void)const_cast<oop&>(_exception_oop = oop(NULL)); 1466 _exception_pc = 0; 1467 _exception_handler_pc = 0; 1468 _is_method_handle_return = 0; 1469 _jvmti_thread_state= NULL; 1470 _should_post_on_exceptions_flag = JNI_FALSE; 1471 _jvmti_get_loaded_classes_closure = NULL; 1472 _interp_only_mode = 0; 1473 _special_runtime_exit_condition = _no_async_condition; 1474 _pending_async_exception = NULL; 1475 _thread_stat = NULL; 1476 _thread_stat = new ThreadStatistics(); 1477 _blocked_on_compilation = false; 1478 _jni_active_critical = 0; 1479 _pending_jni_exception_check_fn = NULL; 1480 _do_not_unlock_if_synchronized = false; 1481 _cached_monitor_info = NULL; 1482 _parker = Parker::Allocate(this); 1483 1484#ifndef PRODUCT 1485 _jmp_ring_index = 0; 1486 for (int ji = 0; ji < jump_ring_buffer_size; ji++) { 1487 record_jump(NULL, NULL, NULL, 0); 1488 } 1489#endif // PRODUCT 1490 1491 set_thread_profiler(NULL); 1492 if (FlatProfiler::is_active()) { 1493 // This is where we would decide to either give each thread it's own profiler 1494 // or use one global one from FlatProfiler, 1495 // or up to some count of the number of profiled threads, etc. 1496 ThreadProfiler* pp = new ThreadProfiler(); 1497 pp->engage(); 1498 set_thread_profiler(pp); 1499 } 1500 1501 // Setup safepoint state info for this thread 1502 ThreadSafepointState::create(this); 1503 1504 debug_only(_java_call_counter = 0); 1505 1506 // JVMTI PopFrame support 1507 _popframe_condition = popframe_inactive; 1508 _popframe_preserved_args = NULL; 1509 _popframe_preserved_args_size = 0; 1510 _frames_to_pop_failed_realloc = 0; 1511 1512 pd_initialize(); 1513} 1514 1515#if INCLUDE_ALL_GCS 1516SATBMarkQueueSet JavaThread::_satb_mark_queue_set; 1517DirtyCardQueueSet JavaThread::_dirty_card_queue_set; 1518#endif // INCLUDE_ALL_GCS 1519 1520JavaThread::JavaThread(bool is_attaching_via_jni) : 1521 Thread() 1522#if INCLUDE_ALL_GCS 1523 , _satb_mark_queue(&_satb_mark_queue_set), 1524 _dirty_card_queue(&_dirty_card_queue_set) 1525#endif // INCLUDE_ALL_GCS 1526{ 1527 initialize(); 1528 if (is_attaching_via_jni) { 1529 _jni_attach_state = _attaching_via_jni; 1530 } else { 1531 _jni_attach_state = _not_attaching_via_jni; 1532 } 1533 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor"); 1534} 1535 1536bool JavaThread::reguard_stack(address cur_sp) { 1537 if (_stack_guard_state != stack_guard_yellow_disabled 1538 && _stack_guard_state != stack_guard_reserved_disabled) { 1539 return true; // Stack already guarded or guard pages not needed. 1540 } 1541 1542 if (register_stack_overflow()) { 1543 // For those architectures which have separate register and 1544 // memory stacks, we must check the register stack to see if 1545 // it has overflowed. 1546 return false; 1547 } 1548 1549 // Java code never executes within the yellow zone: the latter is only 1550 // there to provoke an exception during stack banging. If java code 1551 // is executing there, either StackShadowPages should be larger, or 1552 // some exception code in c1, c2 or the interpreter isn't unwinding 1553 // when it should. 1554 guarantee(cur_sp > stack_yellow_zone_base(), "not enough space to reguard - increase StackShadowPages"); 1555 if (_stack_guard_state == stack_guard_yellow_disabled) { 1556 enable_stack_yellow_zone(); 1557 if (reserved_stack_activation() != stack_base()) { 1558 set_reserved_stack_activation(stack_base()); 1559 } 1560 } else if (_stack_guard_state == stack_guard_reserved_disabled) { 1561 set_reserved_stack_activation(stack_base()); 1562 enable_stack_reserved_zone(); 1563 } 1564 return true; 1565} 1566 1567bool JavaThread::reguard_stack(void) { 1568 return reguard_stack(os::current_stack_pointer()); 1569} 1570 1571 1572void JavaThread::block_if_vm_exited() { 1573 if (_terminated == _vm_exited) { 1574 // _vm_exited is set at safepoint, and Threads_lock is never released 1575 // we will block here forever 1576 Threads_lock->lock_without_safepoint_check(); 1577 ShouldNotReachHere(); 1578 } 1579} 1580 1581 1582// Remove this ifdef when C1 is ported to the compiler interface. 1583static void compiler_thread_entry(JavaThread* thread, TRAPS); 1584static void sweeper_thread_entry(JavaThread* thread, TRAPS); 1585 1586JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : 1587 Thread() 1588#if INCLUDE_ALL_GCS 1589 , _satb_mark_queue(&_satb_mark_queue_set), 1590 _dirty_card_queue(&_dirty_card_queue_set) 1591#endif // INCLUDE_ALL_GCS 1592{ 1593 initialize(); 1594 _jni_attach_state = _not_attaching_via_jni; 1595 set_entry_point(entry_point); 1596 // Create the native thread itself. 1597 // %note runtime_23 1598 os::ThreadType thr_type = os::java_thread; 1599 thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread : 1600 os::java_thread; 1601 os::create_thread(this, thr_type, stack_sz); 1602 // The _osthread may be NULL here because we ran out of memory (too many threads active). 1603 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller 1604 // may hold a lock and all locks must be unlocked before throwing the exception (throwing 1605 // the exception consists of creating the exception object & initializing it, initialization 1606 // will leave the VM via a JavaCall and then all locks must be unlocked). 1607 // 1608 // The thread is still suspended when we reach here. Thread must be explicit started 1609 // by creator! Furthermore, the thread must also explicitly be added to the Threads list 1610 // by calling Threads:add. The reason why this is not done here, is because the thread 1611 // object must be fully initialized (take a look at JVM_Start) 1612} 1613 1614JavaThread::~JavaThread() { 1615 1616 // JSR166 -- return the parker to the free list 1617 Parker::Release(_parker); 1618 _parker = NULL; 1619 1620 // Free any remaining previous UnrollBlock 1621 vframeArray* old_array = vframe_array_last(); 1622 1623 if (old_array != NULL) { 1624 Deoptimization::UnrollBlock* old_info = old_array->unroll_block(); 1625 old_array->set_unroll_block(NULL); 1626 delete old_info; 1627 delete old_array; 1628 } 1629 1630 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals(); 1631 if (deferred != NULL) { 1632 // This can only happen if thread is destroyed before deoptimization occurs. 1633 assert(deferred->length() != 0, "empty array!"); 1634 do { 1635 jvmtiDeferredLocalVariableSet* dlv = deferred->at(0); 1636 deferred->remove_at(0); 1637 // individual jvmtiDeferredLocalVariableSet are CHeapObj's 1638 delete dlv; 1639 } while (deferred->length() != 0); 1640 delete deferred; 1641 } 1642 1643 // All Java related clean up happens in exit 1644 ThreadSafepointState::destroy(this); 1645 if (_thread_profiler != NULL) delete _thread_profiler; 1646 if (_thread_stat != NULL) delete _thread_stat; 1647 1648#if INCLUDE_JVMCI 1649 if (JVMCICounterSize > 0) { 1650 if (jvmci_counters_include(this)) { 1651 for (int i = 0; i < JVMCICounterSize; i++) { 1652 _jvmci_old_thread_counters[i] += _jvmci_counters[i]; 1653 } 1654 } 1655 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters); 1656 } 1657#endif // INCLUDE_JVMCI 1658} 1659 1660 1661// The first routine called by a new Java thread 1662void JavaThread::run() { 1663 // initialize thread-local alloc buffer related fields 1664 this->initialize_tlab(); 1665 1666 // used to test validity of stack trace backs 1667 this->record_base_of_stack_pointer(); 1668 1669 // Record real stack base and size. 1670 this->record_stack_base_and_size(); 1671 1672 this->create_stack_guard_pages(); 1673 1674 this->cache_global_variables(); 1675 1676 // Thread is now sufficient initialized to be handled by the safepoint code as being 1677 // in the VM. Change thread state from _thread_new to _thread_in_vm 1678 ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm); 1679 1680 assert(JavaThread::current() == this, "sanity check"); 1681 assert(!Thread::current()->owns_locks(), "sanity check"); 1682 1683 DTRACE_THREAD_PROBE(start, this); 1684 1685 // This operation might block. We call that after all safepoint checks for a new thread has 1686 // been completed. 1687 this->set_active_handles(JNIHandleBlock::allocate_block()); 1688 1689 if (JvmtiExport::should_post_thread_life()) { 1690 JvmtiExport::post_thread_start(this); 1691 } 1692 1693 EventThreadStart event; 1694 if (event.should_commit()) { 1695 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1696 event.commit(); 1697 } 1698 1699 // We call another function to do the rest so we are sure that the stack addresses used 1700 // from there will be lower than the stack base just computed 1701 thread_main_inner(); 1702 1703 // Note, thread is no longer valid at this point! 1704} 1705 1706 1707void JavaThread::thread_main_inner() { 1708 assert(JavaThread::current() == this, "sanity check"); 1709 assert(this->threadObj() != NULL, "just checking"); 1710 1711 // Execute thread entry point unless this thread has a pending exception 1712 // or has been stopped before starting. 1713 // Note: Due to JVM_StopThread we can have pending exceptions already! 1714 if (!this->has_pending_exception() && 1715 !java_lang_Thread::is_stillborn(this->threadObj())) { 1716 { 1717 ResourceMark rm(this); 1718 this->set_native_thread_name(this->get_thread_name()); 1719 } 1720 HandleMark hm(this); 1721 this->entry_point()(this, this); 1722 } 1723 1724 DTRACE_THREAD_PROBE(stop, this); 1725 1726 this->exit(false); 1727 delete this; 1728} 1729 1730 1731static void ensure_join(JavaThread* thread) { 1732 // We do not need to grap the Threads_lock, since we are operating on ourself. 1733 Handle threadObj(thread, thread->threadObj()); 1734 assert(threadObj.not_null(), "java thread object must exist"); 1735 ObjectLocker lock(threadObj, thread); 1736 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1737 thread->clear_pending_exception(); 1738 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED. 1739 java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED); 1740 // Clear the native thread instance - this makes isAlive return false and allows the join() 1741 // to complete once we've done the notify_all below 1742 java_lang_Thread::set_thread(threadObj(), NULL); 1743 lock.notify_all(thread); 1744 // Ignore pending exception (ThreadDeath), since we are exiting anyway 1745 thread->clear_pending_exception(); 1746} 1747 1748 1749// For any new cleanup additions, please check to see if they need to be applied to 1750// cleanup_failed_attach_current_thread as well. 1751void JavaThread::exit(bool destroy_vm, ExitType exit_type) { 1752 assert(this == JavaThread::current(), "thread consistency check"); 1753 1754 HandleMark hm(this); 1755 Handle uncaught_exception(this, this->pending_exception()); 1756 this->clear_pending_exception(); 1757 Handle threadObj(this, this->threadObj()); 1758 assert(threadObj.not_null(), "Java thread object should be created"); 1759 1760 if (get_thread_profiler() != NULL) { 1761 get_thread_profiler()->disengage(); 1762 ResourceMark rm; 1763 get_thread_profiler()->print(get_thread_name()); 1764 } 1765 1766 1767 // FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place 1768 { 1769 EXCEPTION_MARK; 1770 1771 CLEAR_PENDING_EXCEPTION; 1772 } 1773 if (!destroy_vm) { 1774 if (uncaught_exception.not_null()) { 1775 EXCEPTION_MARK; 1776 // Call method Thread.dispatchUncaughtException(). 1777 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1778 JavaValue result(T_VOID); 1779 JavaCalls::call_virtual(&result, 1780 threadObj, thread_klass, 1781 vmSymbols::dispatchUncaughtException_name(), 1782 vmSymbols::throwable_void_signature(), 1783 uncaught_exception, 1784 THREAD); 1785 if (HAS_PENDING_EXCEPTION) { 1786 ResourceMark rm(this); 1787 jio_fprintf(defaultStream::error_stream(), 1788 "\nException: %s thrown from the UncaughtExceptionHandler" 1789 " in thread \"%s\"\n", 1790 pending_exception()->klass()->external_name(), 1791 get_thread_name()); 1792 CLEAR_PENDING_EXCEPTION; 1793 } 1794 } 1795 1796 // Called before the java thread exit since we want to read info 1797 // from java_lang_Thread object 1798 EventThreadEnd event; 1799 if (event.should_commit()) { 1800 event.set_javalangthread(java_lang_Thread::thread_id(this->threadObj())); 1801 event.commit(); 1802 } 1803 1804 // Call after last event on thread 1805 EVENT_THREAD_EXIT(this); 1806 1807 // Call Thread.exit(). We try 3 times in case we got another Thread.stop during 1808 // the execution of the method. If that is not enough, then we don't really care. Thread.stop 1809 // is deprecated anyhow. 1810 if (!is_Compiler_thread()) { 1811 int count = 3; 1812 while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) { 1813 EXCEPTION_MARK; 1814 JavaValue result(T_VOID); 1815 KlassHandle thread_klass(THREAD, SystemDictionary::Thread_klass()); 1816 JavaCalls::call_virtual(&result, 1817 threadObj, thread_klass, 1818 vmSymbols::exit_method_name(), 1819 vmSymbols::void_method_signature(), 1820 THREAD); 1821 CLEAR_PENDING_EXCEPTION; 1822 } 1823 } 1824 // notify JVMTI 1825 if (JvmtiExport::should_post_thread_life()) { 1826 JvmtiExport::post_thread_end(this); 1827 } 1828 1829 // We have notified the agents that we are exiting, before we go on, 1830 // we must check for a pending external suspend request and honor it 1831 // in order to not surprise the thread that made the suspend request. 1832 while (true) { 1833 { 1834 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1835 if (!is_external_suspend()) { 1836 set_terminated(_thread_exiting); 1837 ThreadService::current_thread_exiting(this); 1838 break; 1839 } 1840 // Implied else: 1841 // Things get a little tricky here. We have a pending external 1842 // suspend request, but we are holding the SR_lock so we 1843 // can't just self-suspend. So we temporarily drop the lock 1844 // and then self-suspend. 1845 } 1846 1847 ThreadBlockInVM tbivm(this); 1848 java_suspend_self(); 1849 1850 // We're done with this suspend request, but we have to loop around 1851 // and check again. Eventually we will get SR_lock without a pending 1852 // external suspend request and will be able to mark ourselves as 1853 // exiting. 1854 } 1855 // no more external suspends are allowed at this point 1856 } else { 1857 // before_exit() has already posted JVMTI THREAD_END events 1858 } 1859 1860 // Notify waiters on thread object. This has to be done after exit() is called 1861 // on the thread (if the thread is the last thread in a daemon ThreadGroup the 1862 // group should have the destroyed bit set before waiters are notified). 1863 ensure_join(this); 1864 assert(!this->has_pending_exception(), "ensure_join should have cleared"); 1865 1866 // 6282335 JNI DetachCurrentThread spec states that all Java monitors 1867 // held by this thread must be released. The spec does not distinguish 1868 // between JNI-acquired and regular Java monitors. We can only see 1869 // regular Java monitors here if monitor enter-exit matching is broken. 1870 // 1871 // Optionally release any monitors for regular JavaThread exits. This 1872 // is provided as a work around for any bugs in monitor enter-exit 1873 // matching. This can be expensive so it is not enabled by default. 1874 // 1875 // ensure_join() ignores IllegalThreadStateExceptions, and so does 1876 // ObjectSynchronizer::release_monitors_owned_by_thread(). 1877 if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) { 1878 // Sanity check even though JNI DetachCurrentThread() would have 1879 // returned JNI_ERR if there was a Java frame. JavaThread exit 1880 // should be done executing Java code by the time we get here. 1881 assert(!this->has_last_Java_frame(), 1882 "should not have a Java frame when detaching or exiting"); 1883 ObjectSynchronizer::release_monitors_owned_by_thread(this); 1884 assert(!this->has_pending_exception(), "release_monitors should have cleared"); 1885 } 1886 1887 // These things needs to be done while we are still a Java Thread. Make sure that thread 1888 // is in a consistent state, in case GC happens 1889 assert(_privileged_stack_top == NULL, "must be NULL when we get here"); 1890 1891 if (active_handles() != NULL) { 1892 JNIHandleBlock* block = active_handles(); 1893 set_active_handles(NULL); 1894 JNIHandleBlock::release_block(block); 1895 } 1896 1897 if (free_handle_block() != NULL) { 1898 JNIHandleBlock* block = free_handle_block(); 1899 set_free_handle_block(NULL); 1900 JNIHandleBlock::release_block(block); 1901 } 1902 1903 // These have to be removed while this is still a valid thread. 1904 remove_stack_guard_pages(); 1905 1906 if (UseTLAB) { 1907 tlab().make_parsable(true); // retire TLAB 1908 } 1909 1910 if (JvmtiEnv::environments_might_exist()) { 1911 JvmtiExport::cleanup_thread(this); 1912 } 1913 1914 // We must flush any deferred card marks before removing a thread from 1915 // the list of active threads. 1916 Universe::heap()->flush_deferred_store_barrier(this); 1917 assert(deferred_card_mark().is_empty(), "Should have been flushed"); 1918 1919#if INCLUDE_ALL_GCS 1920 // We must flush the G1-related buffers before removing a thread 1921 // from the list of active threads. We must do this after any deferred 1922 // card marks have been flushed (above) so that any entries that are 1923 // added to the thread's dirty card queue as a result are not lost. 1924 if (UseG1GC) { 1925 flush_barrier_queues(); 1926 } 1927#endif // INCLUDE_ALL_GCS 1928 1929 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread 1930 Threads::remove(this); 1931} 1932 1933#if INCLUDE_ALL_GCS 1934// Flush G1-related queues. 1935void JavaThread::flush_barrier_queues() { 1936 satb_mark_queue().flush(); 1937 dirty_card_queue().flush(); 1938} 1939 1940void JavaThread::initialize_queues() { 1941 assert(!SafepointSynchronize::is_at_safepoint(), 1942 "we should not be at a safepoint"); 1943 1944 SATBMarkQueue& satb_queue = satb_mark_queue(); 1945 SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set(); 1946 // The SATB queue should have been constructed with its active 1947 // field set to false. 1948 assert(!satb_queue.is_active(), "SATB queue should not be active"); 1949 assert(satb_queue.is_empty(), "SATB queue should be empty"); 1950 // If we are creating the thread during a marking cycle, we should 1951 // set the active field of the SATB queue to true. 1952 if (satb_queue_set.is_active()) { 1953 satb_queue.set_active(true); 1954 } 1955 1956 DirtyCardQueue& dirty_queue = dirty_card_queue(); 1957 // The dirty card queue should have been constructed with its 1958 // active field set to true. 1959 assert(dirty_queue.is_active(), "dirty card queue should be active"); 1960} 1961#endif // INCLUDE_ALL_GCS 1962 1963void JavaThread::cleanup_failed_attach_current_thread() { 1964 if (get_thread_profiler() != NULL) { 1965 get_thread_profiler()->disengage(); 1966 ResourceMark rm; 1967 get_thread_profiler()->print(get_thread_name()); 1968 } 1969 1970 if (active_handles() != NULL) { 1971 JNIHandleBlock* block = active_handles(); 1972 set_active_handles(NULL); 1973 JNIHandleBlock::release_block(block); 1974 } 1975 1976 if (free_handle_block() != NULL) { 1977 JNIHandleBlock* block = free_handle_block(); 1978 set_free_handle_block(NULL); 1979 JNIHandleBlock::release_block(block); 1980 } 1981 1982 // These have to be removed while this is still a valid thread. 1983 remove_stack_guard_pages(); 1984 1985 if (UseTLAB) { 1986 tlab().make_parsable(true); // retire TLAB, if any 1987 } 1988 1989#if INCLUDE_ALL_GCS 1990 if (UseG1GC) { 1991 flush_barrier_queues(); 1992 } 1993#endif // INCLUDE_ALL_GCS 1994 1995 Threads::remove(this); 1996 delete this; 1997} 1998 1999 2000 2001 2002JavaThread* JavaThread::active() { 2003 Thread* thread = Thread::current(); 2004 if (thread->is_Java_thread()) { 2005 return (JavaThread*) thread; 2006 } else { 2007 assert(thread->is_VM_thread(), "this must be a vm thread"); 2008 VM_Operation* op = ((VMThread*) thread)->vm_operation(); 2009 JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread(); 2010 assert(ret->is_Java_thread(), "must be a Java thread"); 2011 return ret; 2012 } 2013} 2014 2015bool JavaThread::is_lock_owned(address adr) const { 2016 if (Thread::is_lock_owned(adr)) return true; 2017 2018 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2019 if (chunk->contains(adr)) return true; 2020 } 2021 2022 return false; 2023} 2024 2025 2026void JavaThread::add_monitor_chunk(MonitorChunk* chunk) { 2027 chunk->set_next(monitor_chunks()); 2028 set_monitor_chunks(chunk); 2029} 2030 2031void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) { 2032 guarantee(monitor_chunks() != NULL, "must be non empty"); 2033 if (monitor_chunks() == chunk) { 2034 set_monitor_chunks(chunk->next()); 2035 } else { 2036 MonitorChunk* prev = monitor_chunks(); 2037 while (prev->next() != chunk) prev = prev->next(); 2038 prev->set_next(chunk->next()); 2039 } 2040} 2041 2042// JVM support. 2043 2044// Note: this function shouldn't block if it's called in 2045// _thread_in_native_trans state (such as from 2046// check_special_condition_for_native_trans()). 2047void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) { 2048 2049 if (has_last_Java_frame() && has_async_condition()) { 2050 // If we are at a polling page safepoint (not a poll return) 2051 // then we must defer async exception because live registers 2052 // will be clobbered by the exception path. Poll return is 2053 // ok because the call we a returning from already collides 2054 // with exception handling registers and so there is no issue. 2055 // (The exception handling path kills call result registers but 2056 // this is ok since the exception kills the result anyway). 2057 2058 if (is_at_poll_safepoint()) { 2059 // if the code we are returning to has deoptimized we must defer 2060 // the exception otherwise live registers get clobbered on the 2061 // exception path before deoptimization is able to retrieve them. 2062 // 2063 RegisterMap map(this, false); 2064 frame caller_fr = last_frame().sender(&map); 2065 assert(caller_fr.is_compiled_frame(), "what?"); 2066 if (caller_fr.is_deoptimized_frame()) { 2067 if (TraceExceptions) { 2068 ResourceMark rm; 2069 tty->print_cr("deferred async exception at compiled safepoint"); 2070 } 2071 return; 2072 } 2073 } 2074 } 2075 2076 JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition(); 2077 if (condition == _no_async_condition) { 2078 // Conditions have changed since has_special_runtime_exit_condition() 2079 // was called: 2080 // - if we were here only because of an external suspend request, 2081 // then that was taken care of above (or cancelled) so we are done 2082 // - if we were here because of another async request, then it has 2083 // been cleared between the has_special_runtime_exit_condition() 2084 // and now so again we are done 2085 return; 2086 } 2087 2088 // Check for pending async. exception 2089 if (_pending_async_exception != NULL) { 2090 // Only overwrite an already pending exception, if it is not a threadDeath. 2091 if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) { 2092 2093 // We cannot call Exceptions::_throw(...) here because we cannot block 2094 set_pending_exception(_pending_async_exception, __FILE__, __LINE__); 2095 2096 if (TraceExceptions) { 2097 ResourceMark rm; 2098 tty->print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this)); 2099 if (has_last_Java_frame()) { 2100 frame f = last_frame(); 2101 tty->print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp())); 2102 } 2103 tty->print_cr(" of type: %s", _pending_async_exception->klass()->external_name()); 2104 } 2105 _pending_async_exception = NULL; 2106 clear_has_async_exception(); 2107 } 2108 } 2109 2110 if (check_unsafe_error && 2111 condition == _async_unsafe_access_error && !has_pending_exception()) { 2112 condition = _no_async_condition; // done 2113 switch (thread_state()) { 2114 case _thread_in_vm: { 2115 JavaThread* THREAD = this; 2116 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2117 } 2118 case _thread_in_native: { 2119 ThreadInVMfromNative tiv(this); 2120 JavaThread* THREAD = this; 2121 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation"); 2122 } 2123 case _thread_in_Java: { 2124 ThreadInVMfromJava tiv(this); 2125 JavaThread* THREAD = this; 2126 THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code"); 2127 } 2128 default: 2129 ShouldNotReachHere(); 2130 } 2131 } 2132 2133 assert(condition == _no_async_condition || has_pending_exception() || 2134 (!check_unsafe_error && condition == _async_unsafe_access_error), 2135 "must have handled the async condition, if no exception"); 2136} 2137 2138void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) { 2139 // 2140 // Check for pending external suspend. Internal suspend requests do 2141 // not use handle_special_runtime_exit_condition(). 2142 // If JNIEnv proxies are allowed, don't self-suspend if the target 2143 // thread is not the current thread. In older versions of jdbx, jdbx 2144 // threads could call into the VM with another thread's JNIEnv so we 2145 // can be here operating on behalf of a suspended thread (4432884). 2146 bool do_self_suspend = is_external_suspend_with_lock(); 2147 if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) { 2148 // 2149 // Because thread is external suspended the safepoint code will count 2150 // thread as at a safepoint. This can be odd because we can be here 2151 // as _thread_in_Java which would normally transition to _thread_blocked 2152 // at a safepoint. We would like to mark the thread as _thread_blocked 2153 // before calling java_suspend_self like all other callers of it but 2154 // we must then observe proper safepoint protocol. (We can't leave 2155 // _thread_blocked with a safepoint in progress). However we can be 2156 // here as _thread_in_native_trans so we can't use a normal transition 2157 // constructor/destructor pair because they assert on that type of 2158 // transition. We could do something like: 2159 // 2160 // JavaThreadState state = thread_state(); 2161 // set_thread_state(_thread_in_vm); 2162 // { 2163 // ThreadBlockInVM tbivm(this); 2164 // java_suspend_self() 2165 // } 2166 // set_thread_state(_thread_in_vm_trans); 2167 // if (safepoint) block; 2168 // set_thread_state(state); 2169 // 2170 // but that is pretty messy. Instead we just go with the way the 2171 // code has worked before and note that this is the only path to 2172 // java_suspend_self that doesn't put the thread in _thread_blocked 2173 // mode. 2174 2175 frame_anchor()->make_walkable(this); 2176 java_suspend_self(); 2177 2178 // We might be here for reasons in addition to the self-suspend request 2179 // so check for other async requests. 2180 } 2181 2182 if (check_asyncs) { 2183 check_and_handle_async_exceptions(); 2184 } 2185} 2186 2187void JavaThread::send_thread_stop(oop java_throwable) { 2188 assert(Thread::current()->is_VM_thread(), "should be in the vm thread"); 2189 assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code"); 2190 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 2191 2192 // Do not throw asynchronous exceptions against the compiler thread 2193 // (the compiler thread should not be a Java thread -- fix in 1.4.2) 2194 if (!can_call_java()) return; 2195 2196 { 2197 // Actually throw the Throwable against the target Thread - however 2198 // only if there is no thread death exception installed already. 2199 if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) { 2200 // If the topmost frame is a runtime stub, then we are calling into 2201 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..) 2202 // must deoptimize the caller before continuing, as the compiled exception handler table 2203 // may not be valid 2204 if (has_last_Java_frame()) { 2205 frame f = last_frame(); 2206 if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) { 2207 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2208 RegisterMap reg_map(this, UseBiasedLocking); 2209 frame compiled_frame = f.sender(®_map); 2210 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) { 2211 Deoptimization::deoptimize(this, compiled_frame, ®_map); 2212 } 2213 } 2214 } 2215 2216 // Set async. pending exception in thread. 2217 set_pending_async_exception(java_throwable); 2218 2219 if (TraceExceptions) { 2220 ResourceMark rm; 2221 tty->print_cr("Pending Async. exception installed of type: %s", _pending_async_exception->klass()->external_name()); 2222 } 2223 // for AbortVMOnException flag 2224 Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name()); 2225 } 2226 } 2227 2228 2229 // Interrupt thread so it will wake up from a potential wait() 2230 Thread::interrupt(this); 2231} 2232 2233// External suspension mechanism. 2234// 2235// Tell the VM to suspend a thread when ever it knows that it does not hold on 2236// to any VM_locks and it is at a transition 2237// Self-suspension will happen on the transition out of the vm. 2238// Catch "this" coming in from JNIEnv pointers when the thread has been freed 2239// 2240// Guarantees on return: 2241// + Target thread will not execute any new bytecode (that's why we need to 2242// force a safepoint) 2243// + Target thread will not enter any new monitors 2244// 2245void JavaThread::java_suspend() { 2246 { MutexLocker mu(Threads_lock); 2247 if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) { 2248 return; 2249 } 2250 } 2251 2252 { MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2253 if (!is_external_suspend()) { 2254 // a racing resume has cancelled us; bail out now 2255 return; 2256 } 2257 2258 // suspend is done 2259 uint32_t debug_bits = 0; 2260 // Warning: is_ext_suspend_completed() may temporarily drop the 2261 // SR_lock to allow the thread to reach a stable thread state if 2262 // it is currently in a transient thread state. 2263 if (is_ext_suspend_completed(false /* !called_by_wait */, 2264 SuspendRetryDelay, &debug_bits)) { 2265 return; 2266 } 2267 } 2268 2269 VM_ForceSafepoint vm_suspend; 2270 VMThread::execute(&vm_suspend); 2271} 2272 2273// Part II of external suspension. 2274// A JavaThread self suspends when it detects a pending external suspend 2275// request. This is usually on transitions. It is also done in places 2276// where continuing to the next transition would surprise the caller, 2277// e.g., monitor entry. 2278// 2279// Returns the number of times that the thread self-suspended. 2280// 2281// Note: DO NOT call java_suspend_self() when you just want to block current 2282// thread. java_suspend_self() is the second stage of cooperative 2283// suspension for external suspend requests and should only be used 2284// to complete an external suspend request. 2285// 2286int JavaThread::java_suspend_self() { 2287 int ret = 0; 2288 2289 // we are in the process of exiting so don't suspend 2290 if (is_exiting()) { 2291 clear_external_suspend(); 2292 return ret; 2293 } 2294 2295 assert(_anchor.walkable() || 2296 (is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()), 2297 "must have walkable stack"); 2298 2299 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2300 2301 assert(!this->is_ext_suspended(), 2302 "a thread trying to self-suspend should not already be suspended"); 2303 2304 if (this->is_suspend_equivalent()) { 2305 // If we are self-suspending as a result of the lifting of a 2306 // suspend equivalent condition, then the suspend_equivalent 2307 // flag is not cleared until we set the ext_suspended flag so 2308 // that wait_for_ext_suspend_completion() returns consistent 2309 // results. 2310 this->clear_suspend_equivalent(); 2311 } 2312 2313 // A racing resume may have cancelled us before we grabbed SR_lock 2314 // above. Or another external suspend request could be waiting for us 2315 // by the time we return from SR_lock()->wait(). The thread 2316 // that requested the suspension may already be trying to walk our 2317 // stack and if we return now, we can change the stack out from under 2318 // it. This would be a "bad thing (TM)" and cause the stack walker 2319 // to crash. We stay self-suspended until there are no more pending 2320 // external suspend requests. 2321 while (is_external_suspend()) { 2322 ret++; 2323 this->set_ext_suspended(); 2324 2325 // _ext_suspended flag is cleared by java_resume() 2326 while (is_ext_suspended()) { 2327 this->SR_lock()->wait(Mutex::_no_safepoint_check_flag); 2328 } 2329 } 2330 2331 return ret; 2332} 2333 2334#ifdef ASSERT 2335// verify the JavaThread has not yet been published in the Threads::list, and 2336// hence doesn't need protection from concurrent access at this stage 2337void JavaThread::verify_not_published() { 2338 if (!Threads_lock->owned_by_self()) { 2339 MutexLockerEx ml(Threads_lock, Mutex::_no_safepoint_check_flag); 2340 assert(!Threads::includes(this), 2341 "java thread shouldn't have been published yet!"); 2342 } else { 2343 assert(!Threads::includes(this), 2344 "java thread shouldn't have been published yet!"); 2345 } 2346} 2347#endif 2348 2349// Slow path when the native==>VM/Java barriers detect a safepoint is in 2350// progress or when _suspend_flags is non-zero. 2351// Current thread needs to self-suspend if there is a suspend request and/or 2352// block if a safepoint is in progress. 2353// Async exception ISN'T checked. 2354// Note only the ThreadInVMfromNative transition can call this function 2355// directly and when thread state is _thread_in_native_trans 2356void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { 2357 assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); 2358 2359 JavaThread *curJT = JavaThread::current(); 2360 bool do_self_suspend = thread->is_external_suspend(); 2361 2362 assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); 2363 2364 // If JNIEnv proxies are allowed, don't self-suspend if the target 2365 // thread is not the current thread. In older versions of jdbx, jdbx 2366 // threads could call into the VM with another thread's JNIEnv so we 2367 // can be here operating on behalf of a suspended thread (4432884). 2368 if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) { 2369 JavaThreadState state = thread->thread_state(); 2370 2371 // We mark this thread_blocked state as a suspend-equivalent so 2372 // that a caller to is_ext_suspend_completed() won't be confused. 2373 // The suspend-equivalent state is cleared by java_suspend_self(). 2374 thread->set_suspend_equivalent(); 2375 2376 // If the safepoint code sees the _thread_in_native_trans state, it will 2377 // wait until the thread changes to other thread state. There is no 2378 // guarantee on how soon we can obtain the SR_lock and complete the 2379 // self-suspend request. It would be a bad idea to let safepoint wait for 2380 // too long. Temporarily change the state to _thread_blocked to 2381 // let the VM thread know that this thread is ready for GC. The problem 2382 // of changing thread state is that safepoint could happen just after 2383 // java_suspend_self() returns after being resumed, and VM thread will 2384 // see the _thread_blocked state. We must check for safepoint 2385 // after restoring the state and make sure we won't leave while a safepoint 2386 // is in progress. 2387 thread->set_thread_state(_thread_blocked); 2388 thread->java_suspend_self(); 2389 thread->set_thread_state(state); 2390 // Make sure new state is seen by VM thread 2391 if (os::is_MP()) { 2392 if (UseMembar) { 2393 // Force a fence between the write above and read below 2394 OrderAccess::fence(); 2395 } else { 2396 // Must use this rather than serialization page in particular on Windows 2397 InterfaceSupport::serialize_memory(thread); 2398 } 2399 } 2400 } 2401 2402 if (SafepointSynchronize::do_call_back()) { 2403 // If we are safepointing, then block the caller which may not be 2404 // the same as the target thread (see above). 2405 SafepointSynchronize::block(curJT); 2406 } 2407 2408 if (thread->is_deopt_suspend()) { 2409 thread->clear_deopt_suspend(); 2410 RegisterMap map(thread, false); 2411 frame f = thread->last_frame(); 2412 while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) { 2413 f = f.sender(&map); 2414 } 2415 if (f.id() == thread->must_deopt_id()) { 2416 thread->clear_must_deopt_id(); 2417 f.deoptimize(thread); 2418 } else { 2419 fatal("missed deoptimization!"); 2420 } 2421 } 2422} 2423 2424// Slow path when the native==>VM/Java barriers detect a safepoint is in 2425// progress or when _suspend_flags is non-zero. 2426// Current thread needs to self-suspend if there is a suspend request and/or 2427// block if a safepoint is in progress. 2428// Also check for pending async exception (not including unsafe access error). 2429// Note only the native==>VM/Java barriers can call this function and when 2430// thread state is _thread_in_native_trans. 2431void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) { 2432 check_safepoint_and_suspend_for_native_trans(thread); 2433 2434 if (thread->has_async_exception()) { 2435 // We are in _thread_in_native_trans state, don't handle unsafe 2436 // access error since that may block. 2437 thread->check_and_handle_async_exceptions(false); 2438 } 2439} 2440 2441// This is a variant of the normal 2442// check_special_condition_for_native_trans with slightly different 2443// semantics for use by critical native wrappers. It does all the 2444// normal checks but also performs the transition back into 2445// thread_in_Java state. This is required so that critical natives 2446// can potentially block and perform a GC if they are the last thread 2447// exiting the GC_locker. 2448void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) { 2449 check_special_condition_for_native_trans(thread); 2450 2451 // Finish the transition 2452 thread->set_thread_state(_thread_in_Java); 2453 2454 if (thread->do_critical_native_unlock()) { 2455 ThreadInVMfromJavaNoAsyncException tiv(thread); 2456 GC_locker::unlock_critical(thread); 2457 thread->clear_critical_native_unlock(); 2458 } 2459} 2460 2461// We need to guarantee the Threads_lock here, since resumes are not 2462// allowed during safepoint synchronization 2463// Can only resume from an external suspension 2464void JavaThread::java_resume() { 2465 assert_locked_or_safepoint(Threads_lock); 2466 2467 // Sanity check: thread is gone, has started exiting or the thread 2468 // was not externally suspended. 2469 if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) { 2470 return; 2471 } 2472 2473 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 2474 2475 clear_external_suspend(); 2476 2477 if (is_ext_suspended()) { 2478 clear_ext_suspended(); 2479 SR_lock()->notify_all(); 2480 } 2481} 2482 2483void JavaThread::create_stack_guard_pages() { 2484 if (! os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) return; 2485 address low_addr = stack_base() - stack_size(); 2486 size_t len = (StackReservedPages + StackYellowPages + StackRedPages) * os::vm_page_size(); 2487 2488 int allocate = os::allocate_stack_guard_pages(); 2489 // warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len); 2490 2491 if (allocate && !os::create_stack_guard_pages((char *) low_addr, len)) { 2492 warning("Attempt to allocate stack guard pages failed."); 2493 return; 2494 } 2495 2496 if (os::guard_memory((char *) low_addr, len)) { 2497 _stack_guard_state = stack_guard_enabled; 2498 } else { 2499 warning("Attempt to protect stack guard pages failed."); 2500 if (os::uncommit_memory((char *) low_addr, len)) { 2501 warning("Attempt to deallocate stack guard pages failed."); 2502 } 2503 } 2504} 2505 2506void JavaThread::remove_stack_guard_pages() { 2507 assert(Thread::current() == this, "from different thread"); 2508 if (_stack_guard_state == stack_guard_unused) return; 2509 address low_addr = stack_base() - stack_size(); 2510 size_t len = (StackReservedPages + StackYellowPages + StackRedPages) * os::vm_page_size(); 2511 2512 if (os::allocate_stack_guard_pages()) { 2513 if (os::remove_stack_guard_pages((char *) low_addr, len)) { 2514 _stack_guard_state = stack_guard_unused; 2515 } else { 2516 warning("Attempt to deallocate stack guard pages failed."); 2517 } 2518 } else { 2519 if (_stack_guard_state == stack_guard_unused) return; 2520 if (os::unguard_memory((char *) low_addr, len)) { 2521 _stack_guard_state = stack_guard_unused; 2522 } else { 2523 warning("Attempt to unprotect stack guard pages failed."); 2524 } 2525 } 2526} 2527 2528void JavaThread::enable_stack_reserved_zone() { 2529 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2530 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2531 2532 // The base notation is from the stack's point of view, growing downward. 2533 // We need to adjust it to work correctly with guard_memory() 2534 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2535 2536 guarantee(base < stack_base(),"Error calculating stack reserved zone"); 2537 guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone"); 2538 2539 if (os::guard_memory((char *) base, stack_reserved_zone_size())) { 2540 _stack_guard_state = stack_guard_enabled; 2541 } else { 2542 warning("Attempt to guard stack reserved zone failed."); 2543 } 2544 enable_register_stack_guard(); 2545} 2546 2547void JavaThread::disable_stack_reserved_zone() { 2548 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2549 assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled"); 2550 2551 // Simply return if called for a thread that does not use guard pages. 2552 if (_stack_guard_state == stack_guard_unused) return; 2553 2554 // The base notation is from the stack's point of view, growing downward. 2555 // We need to adjust it to work correctly with guard_memory() 2556 address base = stack_reserved_zone_base() - stack_reserved_zone_size(); 2557 2558 if (os::unguard_memory((char *)base, stack_reserved_zone_size())) { 2559 _stack_guard_state = stack_guard_reserved_disabled; 2560 } else { 2561 warning("Attempt to unguard stack reserved zone failed."); 2562 } 2563 disable_register_stack_guard(); 2564} 2565 2566void JavaThread::enable_stack_yellow_zone() { 2567 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2568 assert(_stack_guard_state != stack_guard_enabled, "already enabled"); 2569 2570 // The base notation is from the stacks point of view, growing downward. 2571 // We need to adjust it to work correctly with guard_memory() 2572 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2573 2574 guarantee(base < stack_base(), "Error calculating stack yellow zone"); 2575 guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone"); 2576 2577 if (os::guard_memory((char *) base, stack_yellow_zone_size())) { 2578 _stack_guard_state = stack_guard_enabled; 2579 } else { 2580 warning("Attempt to guard stack yellow zone failed."); 2581 } 2582 enable_register_stack_guard(); 2583} 2584 2585void JavaThread::disable_stack_yellow_zone() { 2586 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2587 assert(_stack_guard_state != stack_guard_yellow_disabled, "already disabled"); 2588 2589 // Simply return if called for a thread that does not use guard pages. 2590 if (_stack_guard_state == stack_guard_unused) return; 2591 2592 // The base notation is from the stacks point of view, growing downward. 2593 // We need to adjust it to work correctly with guard_memory() 2594 address base = stack_yellow_zone_base() - stack_yellow_zone_size(); 2595 2596 if (os::unguard_memory((char *)base, stack_yellow_zone_size())) { 2597 _stack_guard_state = stack_guard_yellow_disabled; 2598 } else { 2599 warning("Attempt to unguard stack yellow zone failed."); 2600 } 2601 disable_register_stack_guard(); 2602} 2603 2604void JavaThread::enable_stack_red_zone() { 2605 // The base notation is from the stacks point of view, growing downward. 2606 // We need to adjust it to work correctly with guard_memory() 2607 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2608 address base = stack_red_zone_base() - stack_red_zone_size(); 2609 2610 guarantee(base < stack_base(), "Error calculating stack red zone"); 2611 guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone"); 2612 2613 if (!os::guard_memory((char *) base, stack_red_zone_size())) { 2614 warning("Attempt to guard stack red zone failed."); 2615 } 2616} 2617 2618void JavaThread::disable_stack_red_zone() { 2619 // The base notation is from the stacks point of view, growing downward. 2620 // We need to adjust it to work correctly with guard_memory() 2621 assert(_stack_guard_state != stack_guard_unused, "must be using guard pages."); 2622 address base = stack_red_zone_base() - stack_red_zone_size(); 2623 if (!os::unguard_memory((char *)base, stack_red_zone_size())) { 2624 warning("Attempt to unguard stack red zone failed."); 2625 } 2626} 2627 2628void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) { 2629 // ignore is there is no stack 2630 if (!has_last_Java_frame()) return; 2631 // traverse the stack frames. Starts from top frame. 2632 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2633 frame* fr = fst.current(); 2634 f(fr, fst.register_map()); 2635 } 2636} 2637 2638 2639#ifndef PRODUCT 2640// Deoptimization 2641// Function for testing deoptimization 2642void JavaThread::deoptimize() { 2643 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2644 StackFrameStream fst(this, UseBiasedLocking); 2645 bool deopt = false; // Dump stack only if a deopt actually happens. 2646 bool only_at = strlen(DeoptimizeOnlyAt) > 0; 2647 // Iterate over all frames in the thread and deoptimize 2648 for (; !fst.is_done(); fst.next()) { 2649 if (fst.current()->can_be_deoptimized()) { 2650 2651 if (only_at) { 2652 // Deoptimize only at particular bcis. DeoptimizeOnlyAt 2653 // consists of comma or carriage return separated numbers so 2654 // search for the current bci in that string. 2655 address pc = fst.current()->pc(); 2656 nmethod* nm = (nmethod*) fst.current()->cb(); 2657 ScopeDesc* sd = nm->scope_desc_at(pc); 2658 char buffer[8]; 2659 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci()); 2660 size_t len = strlen(buffer); 2661 const char * found = strstr(DeoptimizeOnlyAt, buffer); 2662 while (found != NULL) { 2663 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') && 2664 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) { 2665 // Check that the bci found is bracketed by terminators. 2666 break; 2667 } 2668 found = strstr(found + 1, buffer); 2669 } 2670 if (!found) { 2671 continue; 2672 } 2673 } 2674 2675 if (DebugDeoptimization && !deopt) { 2676 deopt = true; // One-time only print before deopt 2677 tty->print_cr("[BEFORE Deoptimization]"); 2678 trace_frames(); 2679 trace_stack(); 2680 } 2681 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2682 } 2683 } 2684 2685 if (DebugDeoptimization && deopt) { 2686 tty->print_cr("[AFTER Deoptimization]"); 2687 trace_frames(); 2688 } 2689} 2690 2691 2692// Make zombies 2693void JavaThread::make_zombies() { 2694 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2695 if (fst.current()->can_be_deoptimized()) { 2696 // it is a Java nmethod 2697 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc()); 2698 nm->make_not_entrant(); 2699 } 2700 } 2701} 2702#endif // PRODUCT 2703 2704 2705void JavaThread::deoptimized_wrt_marked_nmethods() { 2706 if (!has_last_Java_frame()) return; 2707 // BiasedLocking needs an updated RegisterMap for the revoke monitors pass 2708 StackFrameStream fst(this, UseBiasedLocking); 2709 for (; !fst.is_done(); fst.next()) { 2710 if (fst.current()->should_be_deoptimized()) { 2711 Deoptimization::deoptimize(this, *fst.current(), fst.register_map()); 2712 } 2713 } 2714} 2715 2716 2717// If the caller is a NamedThread, then remember, in the current scope, 2718// the given JavaThread in its _processed_thread field. 2719class RememberProcessedThread: public StackObj { 2720 NamedThread* _cur_thr; 2721 public: 2722 RememberProcessedThread(JavaThread* jthr) { 2723 Thread* thread = Thread::current(); 2724 if (thread->is_Named_thread()) { 2725 _cur_thr = (NamedThread *)thread; 2726 _cur_thr->set_processed_thread(jthr); 2727 } else { 2728 _cur_thr = NULL; 2729 } 2730 } 2731 2732 ~RememberProcessedThread() { 2733 if (_cur_thr) { 2734 _cur_thr->set_processed_thread(NULL); 2735 } 2736 } 2737}; 2738 2739void JavaThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 2740 // Verify that the deferred card marks have been flushed. 2741 assert(deferred_card_mark().is_empty(), "Should be empty during GC"); 2742 2743 // The ThreadProfiler oops_do is done from FlatProfiler::oops_do 2744 // since there may be more than one thread using each ThreadProfiler. 2745 2746 // Traverse the GCHandles 2747 Thread::oops_do(f, cld_f, cf); 2748 2749 JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);) 2750 2751 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2752 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2753 2754 if (has_last_Java_frame()) { 2755 // Record JavaThread to GC thread 2756 RememberProcessedThread rpt(this); 2757 2758 // Traverse the privileged stack 2759 if (_privileged_stack_top != NULL) { 2760 _privileged_stack_top->oops_do(f); 2761 } 2762 2763 // traverse the registered growable array 2764 if (_array_for_gc != NULL) { 2765 for (int index = 0; index < _array_for_gc->length(); index++) { 2766 f->do_oop(_array_for_gc->adr_at(index)); 2767 } 2768 } 2769 2770 // Traverse the monitor chunks 2771 for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) { 2772 chunk->oops_do(f); 2773 } 2774 2775 // Traverse the execution stack 2776 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2777 fst.current()->oops_do(f, cld_f, cf, fst.register_map()); 2778 } 2779 } 2780 2781 // callee_target is never live across a gc point so NULL it here should 2782 // it still contain a methdOop. 2783 2784 set_callee_target(NULL); 2785 2786 assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!"); 2787 // If we have deferred set_locals there might be oops waiting to be 2788 // written 2789 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals(); 2790 if (list != NULL) { 2791 for (int i = 0; i < list->length(); i++) { 2792 list->at(i)->oops_do(f); 2793 } 2794 } 2795 2796 // Traverse instance variables at the end since the GC may be moving things 2797 // around using this function 2798 f->do_oop((oop*) &_threadObj); 2799 f->do_oop((oop*) &_vm_result); 2800 f->do_oop((oop*) &_exception_oop); 2801 f->do_oop((oop*) &_pending_async_exception); 2802 2803 if (jvmti_thread_state() != NULL) { 2804 jvmti_thread_state()->oops_do(f); 2805 } 2806} 2807 2808void JavaThread::nmethods_do(CodeBlobClosure* cf) { 2809 Thread::nmethods_do(cf); // (super method is a no-op) 2810 2811 assert((!has_last_Java_frame() && java_call_counter() == 0) || 2812 (has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!"); 2813 2814 if (has_last_Java_frame()) { 2815 // Traverse the execution stack 2816 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2817 fst.current()->nmethods_do(cf); 2818 } 2819 } 2820} 2821 2822void JavaThread::metadata_do(void f(Metadata*)) { 2823 if (has_last_Java_frame()) { 2824 // Traverse the execution stack to call f() on the methods in the stack 2825 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 2826 fst.current()->metadata_do(f); 2827 } 2828 } else if (is_Compiler_thread()) { 2829 // need to walk ciMetadata in current compile tasks to keep alive. 2830 CompilerThread* ct = (CompilerThread*)this; 2831 if (ct->env() != NULL) { 2832 ct->env()->metadata_do(f); 2833 } 2834 if (ct->task() != NULL) { 2835 ct->task()->metadata_do(f); 2836 } 2837 } 2838} 2839 2840// Printing 2841const char* _get_thread_state_name(JavaThreadState _thread_state) { 2842 switch (_thread_state) { 2843 case _thread_uninitialized: return "_thread_uninitialized"; 2844 case _thread_new: return "_thread_new"; 2845 case _thread_new_trans: return "_thread_new_trans"; 2846 case _thread_in_native: return "_thread_in_native"; 2847 case _thread_in_native_trans: return "_thread_in_native_trans"; 2848 case _thread_in_vm: return "_thread_in_vm"; 2849 case _thread_in_vm_trans: return "_thread_in_vm_trans"; 2850 case _thread_in_Java: return "_thread_in_Java"; 2851 case _thread_in_Java_trans: return "_thread_in_Java_trans"; 2852 case _thread_blocked: return "_thread_blocked"; 2853 case _thread_blocked_trans: return "_thread_blocked_trans"; 2854 default: return "unknown thread state"; 2855 } 2856} 2857 2858#ifndef PRODUCT 2859void JavaThread::print_thread_state_on(outputStream *st) const { 2860 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state)); 2861}; 2862void JavaThread::print_thread_state() const { 2863 print_thread_state_on(tty); 2864} 2865#endif // PRODUCT 2866 2867// Called by Threads::print() for VM_PrintThreads operation 2868void JavaThread::print_on(outputStream *st) const { 2869 st->print("\"%s\" ", get_thread_name()); 2870 oop thread_oop = threadObj(); 2871 if (thread_oop != NULL) { 2872 st->print("#" INT64_FORMAT " ", java_lang_Thread::thread_id(thread_oop)); 2873 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon "); 2874 st->print("prio=%d ", java_lang_Thread::priority(thread_oop)); 2875 } 2876 Thread::print_on(st); 2877 // print guess for valid stack memory region (assume 4K pages); helps lock debugging 2878 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12)); 2879 if (thread_oop != NULL) { 2880 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop)); 2881 } 2882#ifndef PRODUCT 2883 print_thread_state_on(st); 2884 _safepoint_state->print_on(st); 2885#endif // PRODUCT 2886} 2887 2888// Called by fatal error handler. The difference between this and 2889// JavaThread::print() is that we can't grab lock or allocate memory. 2890void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const { 2891 st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen)); 2892 oop thread_obj = threadObj(); 2893 if (thread_obj != NULL) { 2894 if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon"); 2895 } 2896 st->print(" ["); 2897 st->print("%s", _get_thread_state_name(_thread_state)); 2898 if (osthread()) { 2899 st->print(", id=%d", osthread()->thread_id()); 2900 } 2901 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")", 2902 p2i(_stack_base - _stack_size), p2i(_stack_base)); 2903 st->print("]"); 2904 return; 2905} 2906 2907// Verification 2908 2909static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); } 2910 2911void JavaThread::verify() { 2912 // Verify oops in the thread. 2913 oops_do(&VerifyOopClosure::verify_oop, NULL, NULL); 2914 2915 // Verify the stack frames. 2916 frames_do(frame_verify); 2917} 2918 2919// CR 6300358 (sub-CR 2137150) 2920// Most callers of this method assume that it can't return NULL but a 2921// thread may not have a name whilst it is in the process of attaching to 2922// the VM - see CR 6412693, and there are places where a JavaThread can be 2923// seen prior to having it's threadObj set (eg JNI attaching threads and 2924// if vm exit occurs during initialization). These cases can all be accounted 2925// for such that this method never returns NULL. 2926const char* JavaThread::get_thread_name() const { 2927#ifdef ASSERT 2928 // early safepoints can hit while current thread does not yet have TLS 2929 if (!SafepointSynchronize::is_at_safepoint()) { 2930 Thread *cur = Thread::current(); 2931 if (!(cur->is_Java_thread() && cur == this)) { 2932 // Current JavaThreads are allowed to get their own name without 2933 // the Threads_lock. 2934 assert_locked_or_safepoint(Threads_lock); 2935 } 2936 } 2937#endif // ASSERT 2938 return get_thread_name_string(); 2939} 2940 2941// Returns a non-NULL representation of this thread's name, or a suitable 2942// descriptive string if there is no set name 2943const char* JavaThread::get_thread_name_string(char* buf, int buflen) const { 2944 const char* name_str; 2945 oop thread_obj = threadObj(); 2946 if (thread_obj != NULL) { 2947 oop name = java_lang_Thread::name(thread_obj); 2948 if (name != NULL) { 2949 if (buf == NULL) { 2950 name_str = java_lang_String::as_utf8_string(name); 2951 } else { 2952 name_str = java_lang_String::as_utf8_string(name, buf, buflen); 2953 } 2954 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306 2955 name_str = "<no-name - thread is attaching>"; 2956 } else { 2957 name_str = Thread::name(); 2958 } 2959 } else { 2960 name_str = Thread::name(); 2961 } 2962 assert(name_str != NULL, "unexpected NULL thread name"); 2963 return name_str; 2964} 2965 2966 2967const char* JavaThread::get_threadgroup_name() const { 2968 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2969 oop thread_obj = threadObj(); 2970 if (thread_obj != NULL) { 2971 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2972 if (thread_group != NULL) { 2973 // ThreadGroup.name can be null 2974 return java_lang_ThreadGroup::name(thread_group); 2975 } 2976 } 2977 return NULL; 2978} 2979 2980const char* JavaThread::get_parent_name() const { 2981 debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);) 2982 oop thread_obj = threadObj(); 2983 if (thread_obj != NULL) { 2984 oop thread_group = java_lang_Thread::threadGroup(thread_obj); 2985 if (thread_group != NULL) { 2986 oop parent = java_lang_ThreadGroup::parent(thread_group); 2987 if (parent != NULL) { 2988 // ThreadGroup.name can be null 2989 return java_lang_ThreadGroup::name(parent); 2990 } 2991 } 2992 } 2993 return NULL; 2994} 2995 2996ThreadPriority JavaThread::java_priority() const { 2997 oop thr_oop = threadObj(); 2998 if (thr_oop == NULL) return NormPriority; // Bootstrapping 2999 ThreadPriority priority = java_lang_Thread::priority(thr_oop); 3000 assert(MinPriority <= priority && priority <= MaxPriority, "sanity check"); 3001 return priority; 3002} 3003 3004void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) { 3005 3006 assert(Threads_lock->owner() == Thread::current(), "must have threads lock"); 3007 // Link Java Thread object <-> C++ Thread 3008 3009 // Get the C++ thread object (an oop) from the JNI handle (a jthread) 3010 // and put it into a new Handle. The Handle "thread_oop" can then 3011 // be used to pass the C++ thread object to other methods. 3012 3013 // Set the Java level thread object (jthread) field of the 3014 // new thread (a JavaThread *) to C++ thread object using the 3015 // "thread_oop" handle. 3016 3017 // Set the thread field (a JavaThread *) of the 3018 // oop representing the java_lang_Thread to the new thread (a JavaThread *). 3019 3020 Handle thread_oop(Thread::current(), 3021 JNIHandles::resolve_non_null(jni_thread)); 3022 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(), 3023 "must be initialized"); 3024 set_threadObj(thread_oop()); 3025 java_lang_Thread::set_thread(thread_oop(), this); 3026 3027 if (prio == NoPriority) { 3028 prio = java_lang_Thread::priority(thread_oop()); 3029 assert(prio != NoPriority, "A valid priority should be present"); 3030 } 3031 3032 // Push the Java priority down to the native thread; needs Threads_lock 3033 Thread::set_priority(this, prio); 3034 3035 prepare_ext(); 3036 3037 // Add the new thread to the Threads list and set it in motion. 3038 // We must have threads lock in order to call Threads::add. 3039 // It is crucial that we do not block before the thread is 3040 // added to the Threads list for if a GC happens, then the java_thread oop 3041 // will not be visited by GC. 3042 Threads::add(this); 3043} 3044 3045oop JavaThread::current_park_blocker() { 3046 // Support for JSR-166 locks 3047 oop thread_oop = threadObj(); 3048 if (thread_oop != NULL && 3049 JDK_Version::current().supports_thread_park_blocker()) { 3050 return java_lang_Thread::park_blocker(thread_oop); 3051 } 3052 return NULL; 3053} 3054 3055 3056void JavaThread::print_stack_on(outputStream* st) { 3057 if (!has_last_Java_frame()) return; 3058 ResourceMark rm; 3059 HandleMark hm; 3060 3061 RegisterMap reg_map(this); 3062 vframe* start_vf = last_java_vframe(®_map); 3063 int count = 0; 3064 for (vframe* f = start_vf; f; f = f->sender()) { 3065 if (f->is_java_frame()) { 3066 javaVFrame* jvf = javaVFrame::cast(f); 3067 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci()); 3068 3069 // Print out lock information 3070 if (JavaMonitorsInStackTrace) { 3071 jvf->print_lock_info_on(st, count); 3072 } 3073 } else { 3074 // Ignore non-Java frames 3075 } 3076 3077 // Bail-out case for too deep stacks 3078 count++; 3079 if (MaxJavaStackTraceDepth == count) return; 3080 } 3081} 3082 3083 3084// JVMTI PopFrame support 3085void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) { 3086 assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments"); 3087 if (in_bytes(size_in_bytes) != 0) { 3088 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread); 3089 _popframe_preserved_args_size = in_bytes(size_in_bytes); 3090 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size); 3091 } 3092} 3093 3094void* JavaThread::popframe_preserved_args() { 3095 return _popframe_preserved_args; 3096} 3097 3098ByteSize JavaThread::popframe_preserved_args_size() { 3099 return in_ByteSize(_popframe_preserved_args_size); 3100} 3101 3102WordSize JavaThread::popframe_preserved_args_size_in_words() { 3103 int sz = in_bytes(popframe_preserved_args_size()); 3104 assert(sz % wordSize == 0, "argument size must be multiple of wordSize"); 3105 return in_WordSize(sz / wordSize); 3106} 3107 3108void JavaThread::popframe_free_preserved_args() { 3109 assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice"); 3110 FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args); 3111 _popframe_preserved_args = NULL; 3112 _popframe_preserved_args_size = 0; 3113} 3114 3115#ifndef PRODUCT 3116 3117void JavaThread::trace_frames() { 3118 tty->print_cr("[Describe stack]"); 3119 int frame_no = 1; 3120 for (StackFrameStream fst(this); !fst.is_done(); fst.next()) { 3121 tty->print(" %d. ", frame_no++); 3122 fst.current()->print_value_on(tty, this); 3123 tty->cr(); 3124 } 3125} 3126 3127class PrintAndVerifyOopClosure: public OopClosure { 3128 protected: 3129 template <class T> inline void do_oop_work(T* p) { 3130 oop obj = oopDesc::load_decode_heap_oop(p); 3131 if (obj == NULL) return; 3132 tty->print(INTPTR_FORMAT ": ", p2i(p)); 3133 if (obj->is_oop_or_null()) { 3134 if (obj->is_objArray()) { 3135 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj)); 3136 } else { 3137 obj->print(); 3138 } 3139 } else { 3140 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj)); 3141 } 3142 tty->cr(); 3143 } 3144 public: 3145 virtual void do_oop(oop* p) { do_oop_work(p); } 3146 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 3147}; 3148 3149 3150static void oops_print(frame* f, const RegisterMap *map) { 3151 PrintAndVerifyOopClosure print; 3152 f->print_value(); 3153 f->oops_do(&print, NULL, NULL, (RegisterMap*)map); 3154} 3155 3156// Print our all the locations that contain oops and whether they are 3157// valid or not. This useful when trying to find the oldest frame 3158// where an oop has gone bad since the frame walk is from youngest to 3159// oldest. 3160void JavaThread::trace_oops() { 3161 tty->print_cr("[Trace oops]"); 3162 frames_do(oops_print); 3163} 3164 3165 3166#ifdef ASSERT 3167// Print or validate the layout of stack frames 3168void JavaThread::print_frame_layout(int depth, bool validate_only) { 3169 ResourceMark rm; 3170 PRESERVE_EXCEPTION_MARK; 3171 FrameValues values; 3172 int frame_no = 0; 3173 for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) { 3174 fst.current()->describe(values, ++frame_no); 3175 if (depth == frame_no) break; 3176 } 3177 if (validate_only) { 3178 values.validate(); 3179 } else { 3180 tty->print_cr("[Describe stack layout]"); 3181 values.print(this); 3182 } 3183} 3184#endif 3185 3186void JavaThread::trace_stack_from(vframe* start_vf) { 3187 ResourceMark rm; 3188 int vframe_no = 1; 3189 for (vframe* f = start_vf; f; f = f->sender()) { 3190 if (f->is_java_frame()) { 3191 javaVFrame::cast(f)->print_activation(vframe_no++); 3192 } else { 3193 f->print(); 3194 } 3195 if (vframe_no > StackPrintLimit) { 3196 tty->print_cr("...<more frames>..."); 3197 return; 3198 } 3199 } 3200} 3201 3202 3203void JavaThread::trace_stack() { 3204 if (!has_last_Java_frame()) return; 3205 ResourceMark rm; 3206 HandleMark hm; 3207 RegisterMap reg_map(this); 3208 trace_stack_from(last_java_vframe(®_map)); 3209} 3210 3211 3212#endif // PRODUCT 3213 3214 3215javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) { 3216 assert(reg_map != NULL, "a map must be given"); 3217 frame f = last_frame(); 3218 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) { 3219 if (vf->is_java_frame()) return javaVFrame::cast(vf); 3220 } 3221 return NULL; 3222} 3223 3224 3225Klass* JavaThread::security_get_caller_class(int depth) { 3226 vframeStream vfst(this); 3227 vfst.security_get_caller_frame(depth); 3228 if (!vfst.at_end()) { 3229 return vfst.method()->method_holder(); 3230 } 3231 return NULL; 3232} 3233 3234static void compiler_thread_entry(JavaThread* thread, TRAPS) { 3235 assert(thread->is_Compiler_thread(), "must be compiler thread"); 3236 CompileBroker::compiler_thread_loop(); 3237} 3238 3239static void sweeper_thread_entry(JavaThread* thread, TRAPS) { 3240 NMethodSweeper::sweeper_loop(); 3241} 3242 3243// Create a CompilerThread 3244CompilerThread::CompilerThread(CompileQueue* queue, 3245 CompilerCounters* counters) 3246 : JavaThread(&compiler_thread_entry) { 3247 _env = NULL; 3248 _log = NULL; 3249 _task = NULL; 3250 _queue = queue; 3251 _counters = counters; 3252 _buffer_blob = NULL; 3253 _compiler = NULL; 3254 3255#ifndef PRODUCT 3256 _ideal_graph_printer = NULL; 3257#endif 3258} 3259 3260bool CompilerThread::can_call_java() const { 3261 return _compiler != NULL && _compiler->is_jvmci(); 3262} 3263 3264// Create sweeper thread 3265CodeCacheSweeperThread::CodeCacheSweeperThread() 3266: JavaThread(&sweeper_thread_entry) { 3267 _scanned_nmethod = NULL; 3268} 3269void CodeCacheSweeperThread::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 3270 JavaThread::oops_do(f, cld_f, cf); 3271 if (_scanned_nmethod != NULL && cf != NULL) { 3272 // Safepoints can occur when the sweeper is scanning an nmethod so 3273 // process it here to make sure it isn't unloaded in the middle of 3274 // a scan. 3275 cf->do_code_blob(_scanned_nmethod); 3276 } 3277} 3278 3279 3280// ======= Threads ======== 3281 3282// The Threads class links together all active threads, and provides 3283// operations over all threads. It is protected by its own Mutex 3284// lock, which is also used in other contexts to protect thread 3285// operations from having the thread being operated on from exiting 3286// and going away unexpectedly (e.g., safepoint synchronization) 3287 3288JavaThread* Threads::_thread_list = NULL; 3289int Threads::_number_of_threads = 0; 3290int Threads::_number_of_non_daemon_threads = 0; 3291int Threads::_return_code = 0; 3292int Threads::_thread_claim_parity = 0; 3293size_t JavaThread::_stack_size_at_create = 0; 3294#ifdef ASSERT 3295bool Threads::_vm_complete = false; 3296#endif 3297 3298// All JavaThreads 3299#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next()) 3300 3301// All JavaThreads + all non-JavaThreads (i.e., every thread in the system) 3302void Threads::threads_do(ThreadClosure* tc) { 3303 assert_locked_or_safepoint(Threads_lock); 3304 // ALL_JAVA_THREADS iterates through all JavaThreads 3305 ALL_JAVA_THREADS(p) { 3306 tc->do_thread(p); 3307 } 3308 // Someday we could have a table or list of all non-JavaThreads. 3309 // For now, just manually iterate through them. 3310 tc->do_thread(VMThread::vm_thread()); 3311 Universe::heap()->gc_threads_do(tc); 3312 WatcherThread *wt = WatcherThread::watcher_thread(); 3313 // Strictly speaking, the following NULL check isn't sufficient to make sure 3314 // the data for WatcherThread is still valid upon being examined. However, 3315 // considering that WatchThread terminates when the VM is on the way to 3316 // exit at safepoint, the chance of the above is extremely small. The right 3317 // way to prevent termination of WatcherThread would be to acquire 3318 // Terminator_lock, but we can't do that without violating the lock rank 3319 // checking in some cases. 3320 if (wt != NULL) { 3321 tc->do_thread(wt); 3322 } 3323 3324 // If CompilerThreads ever become non-JavaThreads, add them here 3325} 3326 3327void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) { 3328 TraceTime timer("Initialize java.lang classes", TraceStartupTime); 3329 3330 if (EagerXrunInit && Arguments::init_libraries_at_startup()) { 3331 create_vm_init_libraries(); 3332 } 3333 3334 initialize_class(vmSymbols::java_lang_String(), CHECK); 3335 3336 // Inject CompactStrings value after the static initializers for String ran. 3337 java_lang_String::set_compact_strings(CompactStrings); 3338 3339 // Initialize java_lang.System (needed before creating the thread) 3340 initialize_class(vmSymbols::java_lang_System(), CHECK); 3341 // The VM creates & returns objects of this class. Make sure it's initialized. 3342 initialize_class(vmSymbols::java_lang_Class(), CHECK); 3343 initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK); 3344 Handle thread_group = create_initial_thread_group(CHECK); 3345 Universe::set_main_thread_group(thread_group()); 3346 initialize_class(vmSymbols::java_lang_Thread(), CHECK); 3347 oop thread_object = create_initial_thread(thread_group, main_thread, CHECK); 3348 main_thread->set_threadObj(thread_object); 3349 // Set thread status to running since main thread has 3350 // been started and running. 3351 java_lang_Thread::set_thread_status(thread_object, 3352 java_lang_Thread::RUNNABLE); 3353 3354 // The VM preresolves methods to these classes. Make sure that they get initialized 3355 initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK); 3356 initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK); 3357 call_initializeSystemClass(CHECK); 3358 3359 // get the Java runtime name after java.lang.System is initialized 3360 JDK_Version::set_runtime_name(get_java_runtime_name(THREAD)); 3361 JDK_Version::set_runtime_version(get_java_runtime_version(THREAD)); 3362 3363 // an instance of OutOfMemory exception has been allocated earlier 3364 initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK); 3365 initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK); 3366 initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK); 3367 initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK); 3368 initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK); 3369 initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK); 3370 initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK); 3371 initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK); 3372} 3373 3374void Threads::initialize_jsr292_core_classes(TRAPS) { 3375 initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK); 3376 initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK); 3377 initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK); 3378} 3379 3380jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) { 3381 extern void JDK_Version_init(); 3382 3383 // Preinitialize version info. 3384 VM_Version::early_initialize(); 3385 3386 // Check version 3387 if (!is_supported_jni_version(args->version)) return JNI_EVERSION; 3388 3389 // Initialize the output stream module 3390 ostream_init(); 3391 3392 // Process java launcher properties. 3393 Arguments::process_sun_java_launcher_properties(args); 3394 3395 // Initialize the os module before using TLS 3396 os::init(); 3397 3398 // Record VM creation timing statistics 3399 TraceVmCreationTime create_vm_timer; 3400 create_vm_timer.start(); 3401 3402 // Initialize system properties. 3403 Arguments::init_system_properties(); 3404 3405 // So that JDK version can be used as a discriminator when parsing arguments 3406 JDK_Version_init(); 3407 3408 // Update/Initialize System properties after JDK version number is known 3409 Arguments::init_version_specific_system_properties(); 3410 3411 // Make sure to initialize log configuration *before* parsing arguments 3412 LogConfiguration::initialize(create_vm_timer.begin_time()); 3413 3414 // Parse arguments 3415 jint parse_result = Arguments::parse(args); 3416 if (parse_result != JNI_OK) return parse_result; 3417 3418 os::init_before_ergo(); 3419 3420 jint ergo_result = Arguments::apply_ergo(); 3421 if (ergo_result != JNI_OK) return ergo_result; 3422 3423 // Final check of all ranges after ergonomics which may change values. 3424 if (!CommandLineFlagRangeList::check_ranges()) { 3425 return JNI_EINVAL; 3426 } 3427 3428 // Final check of all 'AfterErgo' constraints after ergonomics which may change values. 3429 bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo); 3430 if (!constraint_result) { 3431 return JNI_EINVAL; 3432 } 3433 3434 if (PauseAtStartup) { 3435 os::pause(); 3436 } 3437 3438 HOTSPOT_VM_INIT_BEGIN(); 3439 3440 // Timing (must come after argument parsing) 3441 TraceTime timer("Create VM", TraceStartupTime); 3442 3443 // Initialize the os module after parsing the args 3444 jint os_init_2_result = os::init_2(); 3445 if (os_init_2_result != JNI_OK) return os_init_2_result; 3446 3447 jint adjust_after_os_result = Arguments::adjust_after_os(); 3448 if (adjust_after_os_result != JNI_OK) return adjust_after_os_result; 3449 3450 // Initialize library-based TLS 3451 ThreadLocalStorage::init(); 3452 3453 // Initialize output stream logging 3454 ostream_init_log(); 3455 3456 // Convert -Xrun to -agentlib: if there is no JVM_OnLoad 3457 // Must be before create_vm_init_agents() 3458 if (Arguments::init_libraries_at_startup()) { 3459 convert_vm_init_libraries_to_agents(); 3460 } 3461 3462 // Launch -agentlib/-agentpath and converted -Xrun agents 3463 if (Arguments::init_agents_at_startup()) { 3464 create_vm_init_agents(); 3465 } 3466 3467 // Initialize Threads state 3468 _thread_list = NULL; 3469 _number_of_threads = 0; 3470 _number_of_non_daemon_threads = 0; 3471 3472 // Initialize global data structures and create system classes in heap 3473 vm_init_globals(); 3474 3475#if INCLUDE_JVMCI 3476 if (JVMCICounterSize > 0) { 3477 JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal); 3478 memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize); 3479 } else { 3480 JavaThread::_jvmci_old_thread_counters = NULL; 3481 } 3482#endif // INCLUDE_JVMCI 3483 3484 // Attach the main thread to this os thread 3485 JavaThread* main_thread = new JavaThread(); 3486 main_thread->set_thread_state(_thread_in_vm); 3487 main_thread->initialize_thread_current(); 3488 // must do this before set_active_handles 3489 main_thread->record_stack_base_and_size(); 3490 main_thread->set_active_handles(JNIHandleBlock::allocate_block()); 3491 3492 if (!main_thread->set_as_starting_thread()) { 3493 vm_shutdown_during_initialization( 3494 "Failed necessary internal allocation. Out of swap space"); 3495 delete main_thread; 3496 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3497 return JNI_ENOMEM; 3498 } 3499 3500 // Enable guard page *after* os::create_main_thread(), otherwise it would 3501 // crash Linux VM, see notes in os_linux.cpp. 3502 main_thread->create_stack_guard_pages(); 3503 3504 // Initialize Java-Level synchronization subsystem 3505 ObjectMonitor::Initialize(); 3506 3507 // Initialize global modules 3508 jint status = init_globals(); 3509 if (status != JNI_OK) { 3510 delete main_thread; 3511 *canTryAgain = false; // don't let caller call JNI_CreateJavaVM again 3512 return status; 3513 } 3514 3515 // Should be done after the heap is fully created 3516 main_thread->cache_global_variables(); 3517 3518 HandleMark hm; 3519 3520 { MutexLocker mu(Threads_lock); 3521 Threads::add(main_thread); 3522 } 3523 3524 // Any JVMTI raw monitors entered in onload will transition into 3525 // real raw monitor. VM is setup enough here for raw monitor enter. 3526 JvmtiExport::transition_pending_onload_raw_monitors(); 3527 3528 // Create the VMThread 3529 { TraceTime timer("Start VMThread", TraceStartupTime); 3530 VMThread::create(); 3531 Thread* vmthread = VMThread::vm_thread(); 3532 3533 if (!os::create_thread(vmthread, os::vm_thread)) { 3534 vm_exit_during_initialization("Cannot create VM thread. " 3535 "Out of system resources."); 3536 } 3537 3538 // Wait for the VM thread to become ready, and VMThread::run to initialize 3539 // Monitors can have spurious returns, must always check another state flag 3540 { 3541 MutexLocker ml(Notify_lock); 3542 os::start_thread(vmthread); 3543 while (vmthread->active_handles() == NULL) { 3544 Notify_lock->wait(); 3545 } 3546 } 3547 } 3548 3549 assert(Universe::is_fully_initialized(), "not initialized"); 3550 if (VerifyDuringStartup) { 3551 // Make sure we're starting with a clean slate. 3552 VM_Verify verify_op; 3553 VMThread::execute(&verify_op); 3554 } 3555 3556 Thread* THREAD = Thread::current(); 3557 3558 // At this point, the Universe is initialized, but we have not executed 3559 // any byte code. Now is a good time (the only time) to dump out the 3560 // internal state of the JVM for sharing. 3561 if (DumpSharedSpaces) { 3562 MetaspaceShared::preload_and_dump(CHECK_JNI_ERR); 3563 ShouldNotReachHere(); 3564 } 3565 3566 // Always call even when there are not JVMTI environments yet, since environments 3567 // may be attached late and JVMTI must track phases of VM execution 3568 JvmtiExport::enter_start_phase(); 3569 3570 // Notify JVMTI agents that VM has started (JNI is up) - nop if no agents. 3571 JvmtiExport::post_vm_start(); 3572 3573 initialize_java_lang_classes(main_thread, CHECK_JNI_ERR); 3574 3575 // We need this for ClassDataSharing - the initial vm.info property is set 3576 // with the default value of CDS "sharing" which may be reset through 3577 // command line options. 3578 reset_vm_info_property(CHECK_JNI_ERR); 3579 3580 quicken_jni_functions(); 3581 3582 // Must be run after init_ft which initializes ft_enabled 3583 if (TRACE_INITIALIZE() != JNI_OK) { 3584 vm_exit_during_initialization("Failed to initialize tracing backend"); 3585 } 3586 3587 // Set flag that basic initialization has completed. Used by exceptions and various 3588 // debug stuff, that does not work until all basic classes have been initialized. 3589 set_init_completed(); 3590 3591 LogConfiguration::post_initialize(); 3592 Metaspace::post_initialize(); 3593 3594 HOTSPOT_VM_INIT_END(); 3595 3596 // record VM initialization completion time 3597#if INCLUDE_MANAGEMENT 3598 Management::record_vm_init_completed(); 3599#endif // INCLUDE_MANAGEMENT 3600 3601 // Compute system loader. Note that this has to occur after set_init_completed, since 3602 // valid exceptions may be thrown in the process. 3603 // Note that we do not use CHECK_0 here since we are inside an EXCEPTION_MARK and 3604 // set_init_completed has just been called, causing exceptions not to be shortcut 3605 // anymore. We call vm_exit_during_initialization directly instead. 3606 SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR)); 3607 3608#if INCLUDE_ALL_GCS 3609 // Support for ConcurrentMarkSweep. This should be cleaned up 3610 // and better encapsulated. The ugly nested if test would go away 3611 // once things are properly refactored. XXX YSR 3612 if (UseConcMarkSweepGC || UseG1GC) { 3613 if (UseConcMarkSweepGC) { 3614 ConcurrentMarkSweepThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3615 } else { 3616 ConcurrentMarkThread::makeSurrogateLockerThread(CHECK_JNI_ERR); 3617 } 3618 } 3619#endif // INCLUDE_ALL_GCS 3620 3621 // Always call even when there are not JVMTI environments yet, since environments 3622 // may be attached late and JVMTI must track phases of VM execution 3623 JvmtiExport::enter_live_phase(); 3624 3625 // Signal Dispatcher needs to be started before VMInit event is posted 3626 os::signal_init(); 3627 3628 // Start Attach Listener if +StartAttachListener or it can't be started lazily 3629 if (!DisableAttachMechanism) { 3630 AttachListener::vm_start(); 3631 if (StartAttachListener || AttachListener::init_at_startup()) { 3632 AttachListener::init(); 3633 } 3634 } 3635 3636 // Launch -Xrun agents 3637 // Must be done in the JVMTI live phase so that for backward compatibility the JDWP 3638 // back-end can launch with -Xdebug -Xrunjdwp. 3639 if (!EagerXrunInit && Arguments::init_libraries_at_startup()) { 3640 create_vm_init_libraries(); 3641 } 3642 3643 // Notify JVMTI agents that VM initialization is complete - nop if no agents. 3644 JvmtiExport::post_vm_initialized(); 3645 3646 if (TRACE_START() != JNI_OK) { 3647 vm_exit_during_initialization("Failed to start tracing backend."); 3648 } 3649 3650 if (CleanChunkPoolAsync) { 3651 Chunk::start_chunk_pool_cleaner_task(); 3652 } 3653 3654#if INCLUDE_JVMCI 3655 if (EnableJVMCI) { 3656 const char* jvmciCompiler = Arguments::PropertyList_get_value(Arguments::system_properties(), "jvmci.compiler"); 3657 if (jvmciCompiler != NULL) { 3658 JVMCIRuntime::save_compiler(jvmciCompiler); 3659 } 3660 JVMCIRuntime::maybe_print_flags(CHECK_JNI_ERR); 3661 } 3662#endif // INCLUDE_JVMCI 3663 3664 // initialize compiler(s) 3665#if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI 3666 CompileBroker::compilation_init(CHECK_JNI_ERR); 3667#endif 3668 3669 // Pre-initialize some JSR292 core classes to avoid deadlock during class loading. 3670 // It is done after compilers are initialized, because otherwise compilations of 3671 // signature polymorphic MH intrinsics can be missed 3672 // (see SystemDictionary::find_method_handle_intrinsic). 3673 initialize_jsr292_core_classes(CHECK_JNI_ERR); 3674 3675#if INCLUDE_MANAGEMENT 3676 Management::initialize(THREAD); 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#endif // INCLUDE_MANAGEMENT 3685 3686 if (Arguments::has_profile()) FlatProfiler::engage(main_thread, true); 3687 if (MemProfiling) MemProfiler::engage(); 3688 StatSampler::engage(); 3689 if (CheckJNICalls) JniPeriodicChecker::engage(); 3690 3691 BiasedLocking::init(); 3692 3693#if INCLUDE_RTM_OPT 3694 RTMLockingCounters::init(); 3695#endif 3696 3697 if (JDK_Version::current().post_vm_init_hook_enabled()) { 3698 call_postVMInitHook(THREAD); 3699 // The Java side of PostVMInitHook.run must deal with all 3700 // exceptions and provide means of diagnosis. 3701 if (HAS_PENDING_EXCEPTION) { 3702 CLEAR_PENDING_EXCEPTION; 3703 } 3704 } 3705 3706 { 3707 MutexLocker ml(PeriodicTask_lock); 3708 // Make sure the WatcherThread can be started by WatcherThread::start() 3709 // or by dynamic enrollment. 3710 WatcherThread::make_startable(); 3711 // Start up the WatcherThread if there are any periodic tasks 3712 // NOTE: All PeriodicTasks should be registered by now. If they 3713 // aren't, late joiners might appear to start slowly (we might 3714 // take a while to process their first tick). 3715 if (PeriodicTask::num_tasks() > 0) { 3716 WatcherThread::start(); 3717 } 3718 } 3719 3720 CodeCacheExtensions::complete_step(CodeCacheExtensionsSteps::CreateVM); 3721 3722 create_vm_timer.end(); 3723#ifdef ASSERT 3724 _vm_complete = true; 3725#endif 3726 return JNI_OK; 3727} 3728 3729// type for the Agent_OnLoad and JVM_OnLoad entry points 3730extern "C" { 3731 typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *); 3732} 3733// Find a command line agent library and return its entry point for 3734// -agentlib: -agentpath: -Xrun 3735// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array. 3736static OnLoadEntry_t lookup_on_load(AgentLibrary* agent, 3737 const char *on_load_symbols[], 3738 size_t num_symbol_entries) { 3739 OnLoadEntry_t on_load_entry = NULL; 3740 void *library = NULL; 3741 3742 if (!agent->valid()) { 3743 char buffer[JVM_MAXPATHLEN]; 3744 char ebuf[1024] = ""; 3745 const char *name = agent->name(); 3746 const char *msg = "Could not find agent library "; 3747 3748 // First check to see if agent is statically linked into executable 3749 if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) { 3750 library = agent->os_lib(); 3751 } else if (agent->is_absolute_path()) { 3752 library = os::dll_load(name, ebuf, sizeof ebuf); 3753 if (library == NULL) { 3754 const char *sub_msg = " in absolute path, with error: "; 3755 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3756 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3757 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3758 // If we can't find the agent, exit. 3759 vm_exit_during_initialization(buf, NULL); 3760 FREE_C_HEAP_ARRAY(char, buf); 3761 } 3762 } else { 3763 // Try to load the agent from the standard dll directory 3764 if (os::dll_build_name(buffer, sizeof(buffer), Arguments::get_dll_dir(), 3765 name)) { 3766 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3767 } 3768 if (library == NULL) { // Try the local directory 3769 char ns[1] = {0}; 3770 if (os::dll_build_name(buffer, sizeof(buffer), ns, name)) { 3771 library = os::dll_load(buffer, ebuf, sizeof ebuf); 3772 } 3773 if (library == NULL) { 3774 const char *sub_msg = " on the library path, with error: "; 3775 size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1; 3776 char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread); 3777 jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf); 3778 // If we can't find the agent, exit. 3779 vm_exit_during_initialization(buf, NULL); 3780 FREE_C_HEAP_ARRAY(char, buf); 3781 } 3782 } 3783 } 3784 agent->set_os_lib(library); 3785 agent->set_valid(); 3786 } 3787 3788 // Find the OnLoad function. 3789 on_load_entry = 3790 CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent, 3791 false, 3792 on_load_symbols, 3793 num_symbol_entries)); 3794 return on_load_entry; 3795} 3796 3797// Find the JVM_OnLoad entry point 3798static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) { 3799 const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS; 3800 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3801} 3802 3803// Find the Agent_OnLoad entry point 3804static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) { 3805 const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS; 3806 return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*)); 3807} 3808 3809// For backwards compatibility with -Xrun 3810// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be 3811// treated like -agentpath: 3812// Must be called before agent libraries are created 3813void Threads::convert_vm_init_libraries_to_agents() { 3814 AgentLibrary* agent; 3815 AgentLibrary* next; 3816 3817 for (agent = Arguments::libraries(); agent != NULL; agent = next) { 3818 next = agent->next(); // cache the next agent now as this agent may get moved off this list 3819 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3820 3821 // If there is an JVM_OnLoad function it will get called later, 3822 // otherwise see if there is an Agent_OnLoad 3823 if (on_load_entry == NULL) { 3824 on_load_entry = lookup_agent_on_load(agent); 3825 if (on_load_entry != NULL) { 3826 // switch it to the agent list -- so that Agent_OnLoad will be called, 3827 // JVM_OnLoad won't be attempted and Agent_OnUnload will 3828 Arguments::convert_library_to_agent(agent); 3829 } else { 3830 vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name()); 3831 } 3832 } 3833 } 3834} 3835 3836// Create agents for -agentlib: -agentpath: and converted -Xrun 3837// Invokes Agent_OnLoad 3838// Called very early -- before JavaThreads exist 3839void Threads::create_vm_init_agents() { 3840 extern struct JavaVM_ main_vm; 3841 AgentLibrary* agent; 3842 3843 JvmtiExport::enter_onload_phase(); 3844 3845 for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3846 OnLoadEntry_t on_load_entry = lookup_agent_on_load(agent); 3847 3848 if (on_load_entry != NULL) { 3849 // Invoke the Agent_OnLoad function 3850 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3851 if (err != JNI_OK) { 3852 vm_exit_during_initialization("agent library failed to init", agent->name()); 3853 } 3854 } else { 3855 vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name()); 3856 } 3857 } 3858 JvmtiExport::enter_primordial_phase(); 3859} 3860 3861extern "C" { 3862 typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *); 3863} 3864 3865void Threads::shutdown_vm_agents() { 3866 // Send any Agent_OnUnload notifications 3867 const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS; 3868 size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols); 3869 extern struct JavaVM_ main_vm; 3870 for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) { 3871 3872 // Find the Agent_OnUnload function. 3873 Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t, 3874 os::find_agent_function(agent, 3875 false, 3876 on_unload_symbols, 3877 num_symbol_entries)); 3878 3879 // Invoke the Agent_OnUnload function 3880 if (unload_entry != NULL) { 3881 JavaThread* thread = JavaThread::current(); 3882 ThreadToNativeFromVM ttn(thread); 3883 HandleMark hm(thread); 3884 (*unload_entry)(&main_vm); 3885 } 3886 } 3887} 3888 3889// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries 3890// Invokes JVM_OnLoad 3891void Threads::create_vm_init_libraries() { 3892 extern struct JavaVM_ main_vm; 3893 AgentLibrary* agent; 3894 3895 for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) { 3896 OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent); 3897 3898 if (on_load_entry != NULL) { 3899 // Invoke the JVM_OnLoad function 3900 JavaThread* thread = JavaThread::current(); 3901 ThreadToNativeFromVM ttn(thread); 3902 HandleMark hm(thread); 3903 jint err = (*on_load_entry)(&main_vm, agent->options(), NULL); 3904 if (err != JNI_OK) { 3905 vm_exit_during_initialization("-Xrun library failed to init", agent->name()); 3906 } 3907 } else { 3908 vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name()); 3909 } 3910 } 3911} 3912 3913JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) { 3914 assert(Threads_lock->owned_by_self(), "Must hold Threads_lock"); 3915 3916 JavaThread* java_thread = NULL; 3917 // Sequential search for now. Need to do better optimization later. 3918 for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) { 3919 oop tobj = thread->threadObj(); 3920 if (!thread->is_exiting() && 3921 tobj != NULL && 3922 java_tid == java_lang_Thread::thread_id(tobj)) { 3923 java_thread = thread; 3924 break; 3925 } 3926 } 3927 return java_thread; 3928} 3929 3930 3931// Last thread running calls java.lang.Shutdown.shutdown() 3932void JavaThread::invoke_shutdown_hooks() { 3933 HandleMark hm(this); 3934 3935 // We could get here with a pending exception, if so clear it now. 3936 if (this->has_pending_exception()) { 3937 this->clear_pending_exception(); 3938 } 3939 3940 EXCEPTION_MARK; 3941 Klass* k = 3942 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(), 3943 THREAD); 3944 if (k != NULL) { 3945 // SystemDictionary::resolve_or_null will return null if there was 3946 // an exception. If we cannot load the Shutdown class, just don't 3947 // call Shutdown.shutdown() at all. This will mean the shutdown hooks 3948 // and finalizers (if runFinalizersOnExit is set) won't be run. 3949 // Note that if a shutdown hook was registered or runFinalizersOnExit 3950 // was called, the Shutdown class would have already been loaded 3951 // (Runtime.addShutdownHook and runFinalizersOnExit will load it). 3952 instanceKlassHandle shutdown_klass (THREAD, k); 3953 JavaValue result(T_VOID); 3954 JavaCalls::call_static(&result, 3955 shutdown_klass, 3956 vmSymbols::shutdown_method_name(), 3957 vmSymbols::void_method_signature(), 3958 THREAD); 3959 } 3960 CLEAR_PENDING_EXCEPTION; 3961} 3962 3963// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when 3964// the program falls off the end of main(). Another VM exit path is through 3965// vm_exit() when the program calls System.exit() to return a value or when 3966// there is a serious error in VM. The two shutdown paths are not exactly 3967// the same, but they share Shutdown.shutdown() at Java level and before_exit() 3968// and VM_Exit op at VM level. 3969// 3970// Shutdown sequence: 3971// + Shutdown native memory tracking if it is on 3972// + Wait until we are the last non-daemon thread to execute 3973// <-- every thing is still working at this moment --> 3974// + Call java.lang.Shutdown.shutdown(), which will invoke Java level 3975// shutdown hooks, run finalizers if finalization-on-exit 3976// + Call before_exit(), prepare for VM exit 3977// > run VM level shutdown hooks (they are registered through JVM_OnExit(), 3978// currently the only user of this mechanism is File.deleteOnExit()) 3979// > stop flat profiler, StatSampler, watcher thread, CMS threads, 3980// post thread end and vm death events to JVMTI, 3981// stop signal thread 3982// + Call JavaThread::exit(), it will: 3983// > release JNI handle blocks, remove stack guard pages 3984// > remove this thread from Threads list 3985// <-- no more Java code from this thread after this point --> 3986// + Stop VM thread, it will bring the remaining VM to a safepoint and stop 3987// the compiler threads at safepoint 3988// <-- do not use anything that could get blocked by Safepoint --> 3989// + Disable tracing at JNI/JVM barriers 3990// + Set _vm_exited flag for threads that are still running native code 3991// + Delete this thread 3992// + Call exit_globals() 3993// > deletes tty 3994// > deletes PerfMemory resources 3995// + Return to caller 3996 3997bool Threads::destroy_vm() { 3998 JavaThread* thread = JavaThread::current(); 3999 4000#ifdef ASSERT 4001 _vm_complete = false; 4002#endif 4003 // Wait until we are the last non-daemon thread to execute 4004 { MutexLocker nu(Threads_lock); 4005 while (Threads::number_of_non_daemon_threads() > 1) 4006 // This wait should make safepoint checks, wait without a timeout, 4007 // and wait as a suspend-equivalent condition. 4008 // 4009 // Note: If the FlatProfiler is running and this thread is waiting 4010 // for another non-daemon thread to finish, then the FlatProfiler 4011 // is waiting for the external suspend request on this thread to 4012 // complete. wait_for_ext_suspend_completion() will eventually 4013 // timeout, but that takes time. Making this wait a suspend- 4014 // equivalent condition solves that timeout problem. 4015 // 4016 Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0, 4017 Mutex::_as_suspend_equivalent_flag); 4018 } 4019 4020 // Hang forever on exit if we are reporting an error. 4021 if (ShowMessageBoxOnError && is_error_reported()) { 4022 os::infinite_sleep(); 4023 } 4024 os::wait_for_keypress_at_exit(); 4025 4026 // run Java level shutdown hooks 4027 thread->invoke_shutdown_hooks(); 4028 4029 before_exit(thread); 4030 4031 thread->exit(true); 4032 4033 // Stop VM thread. 4034 { 4035 // 4945125 The vm thread comes to a safepoint during exit. 4036 // GC vm_operations can get caught at the safepoint, and the 4037 // heap is unparseable if they are caught. Grab the Heap_lock 4038 // to prevent this. The GC vm_operations will not be able to 4039 // queue until after the vm thread is dead. After this point, 4040 // we'll never emerge out of the safepoint before the VM exits. 4041 4042 MutexLocker ml(Heap_lock); 4043 4044 VMThread::wait_for_vm_thread_exit(); 4045 assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint"); 4046 VMThread::destroy(); 4047 } 4048 4049 // clean up ideal graph printers 4050#if defined(COMPILER2) && !defined(PRODUCT) 4051 IdealGraphPrinter::clean_up(); 4052#endif 4053 4054 // Now, all Java threads are gone except daemon threads. Daemon threads 4055 // running Java code or in VM are stopped by the Safepoint. However, 4056 // daemon threads executing native code are still running. But they 4057 // will be stopped at native=>Java/VM barriers. Note that we can't 4058 // simply kill or suspend them, as it is inherently deadlock-prone. 4059 4060 VM_Exit::set_vm_exited(); 4061 4062 notify_vm_shutdown(); 4063 4064 delete thread; 4065 4066#if INCLUDE_JVMCI 4067 if (JVMCICounterSize > 0) { 4068 FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters); 4069 } 4070#endif 4071 4072 // exit_globals() will delete tty 4073 exit_globals(); 4074 4075 LogConfiguration::finalize(); 4076 4077 return true; 4078} 4079 4080 4081jboolean Threads::is_supported_jni_version_including_1_1(jint version) { 4082 if (version == JNI_VERSION_1_1) return JNI_TRUE; 4083 return is_supported_jni_version(version); 4084} 4085 4086 4087jboolean Threads::is_supported_jni_version(jint version) { 4088 if (version == JNI_VERSION_1_2) return JNI_TRUE; 4089 if (version == JNI_VERSION_1_4) return JNI_TRUE; 4090 if (version == JNI_VERSION_1_6) return JNI_TRUE; 4091 if (version == JNI_VERSION_1_8) return JNI_TRUE; 4092 return JNI_FALSE; 4093} 4094 4095 4096void Threads::add(JavaThread* p, bool force_daemon) { 4097 // The threads lock must be owned at this point 4098 assert_locked_or_safepoint(Threads_lock); 4099 4100 // See the comment for this method in thread.hpp for its purpose and 4101 // why it is called here. 4102 p->initialize_queues(); 4103 p->set_next(_thread_list); 4104 _thread_list = p; 4105 _number_of_threads++; 4106 oop threadObj = p->threadObj(); 4107 bool daemon = true; 4108 // Bootstrapping problem: threadObj can be null for initial 4109 // JavaThread (or for threads attached via JNI) 4110 if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) { 4111 _number_of_non_daemon_threads++; 4112 daemon = false; 4113 } 4114 4115 ThreadService::add_thread(p, daemon); 4116 4117 // Possible GC point. 4118 Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p)); 4119} 4120 4121void Threads::remove(JavaThread* p) { 4122 // Extra scope needed for Thread_lock, so we can check 4123 // that we do not remove thread without safepoint code notice 4124 { MutexLocker ml(Threads_lock); 4125 4126 assert(includes(p), "p must be present"); 4127 4128 JavaThread* current = _thread_list; 4129 JavaThread* prev = NULL; 4130 4131 while (current != p) { 4132 prev = current; 4133 current = current->next(); 4134 } 4135 4136 if (prev) { 4137 prev->set_next(current->next()); 4138 } else { 4139 _thread_list = p->next(); 4140 } 4141 _number_of_threads--; 4142 oop threadObj = p->threadObj(); 4143 bool daemon = true; 4144 if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) { 4145 _number_of_non_daemon_threads--; 4146 daemon = false; 4147 4148 // Only one thread left, do a notify on the Threads_lock so a thread waiting 4149 // on destroy_vm will wake up. 4150 if (number_of_non_daemon_threads() == 1) { 4151 Threads_lock->notify_all(); 4152 } 4153 } 4154 ThreadService::remove_thread(p, daemon); 4155 4156 // Make sure that safepoint code disregard this thread. This is needed since 4157 // the thread might mess around with locks after this point. This can cause it 4158 // to do callbacks into the safepoint code. However, the safepoint code is not aware 4159 // of this thread since it is removed from the queue. 4160 p->set_terminated_value(); 4161 } // unlock Threads_lock 4162 4163 // Since Events::log uses a lock, we grab it outside the Threads_lock 4164 Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p)); 4165} 4166 4167// Threads_lock must be held when this is called (or must be called during a safepoint) 4168bool Threads::includes(JavaThread* p) { 4169 assert(Threads_lock->is_locked(), "sanity check"); 4170 ALL_JAVA_THREADS(q) { 4171 if (q == p) { 4172 return true; 4173 } 4174 } 4175 return false; 4176} 4177 4178// Operations on the Threads list for GC. These are not explicitly locked, 4179// but the garbage collector must provide a safe context for them to run. 4180// In particular, these things should never be called when the Threads_lock 4181// is held by some other thread. (Note: the Safepoint abstraction also 4182// uses the Threads_lock to guarantee this property. It also makes sure that 4183// all threads gets blocked when exiting or starting). 4184 4185void Threads::oops_do(OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4186 ALL_JAVA_THREADS(p) { 4187 p->oops_do(f, cld_f, cf); 4188 } 4189 VMThread::vm_thread()->oops_do(f, cld_f, cf); 4190} 4191 4192void Threads::change_thread_claim_parity() { 4193 // Set the new claim parity. 4194 assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2, 4195 "Not in range."); 4196 _thread_claim_parity++; 4197 if (_thread_claim_parity == 3) _thread_claim_parity = 1; 4198 assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2, 4199 "Not in range."); 4200} 4201 4202#ifdef ASSERT 4203void Threads::assert_all_threads_claimed() { 4204 ALL_JAVA_THREADS(p) { 4205 const int thread_parity = p->oops_do_parity(); 4206 assert((thread_parity == _thread_claim_parity), 4207 "Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity); 4208 } 4209} 4210#endif // ASSERT 4211 4212void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CLDClosure* cld_f, CodeBlobClosure* cf) { 4213 int cp = Threads::thread_claim_parity(); 4214 ALL_JAVA_THREADS(p) { 4215 if (p->claim_oops_do(is_par, cp)) { 4216 p->oops_do(f, cld_f, cf); 4217 } 4218 } 4219 VMThread* vmt = VMThread::vm_thread(); 4220 if (vmt->claim_oops_do(is_par, cp)) { 4221 vmt->oops_do(f, cld_f, cf); 4222 } 4223} 4224 4225#if INCLUDE_ALL_GCS 4226// Used by ParallelScavenge 4227void Threads::create_thread_roots_tasks(GCTaskQueue* q) { 4228 ALL_JAVA_THREADS(p) { 4229 q->enqueue(new ThreadRootsTask(p)); 4230 } 4231 q->enqueue(new ThreadRootsTask(VMThread::vm_thread())); 4232} 4233 4234// Used by Parallel Old 4235void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) { 4236 ALL_JAVA_THREADS(p) { 4237 q->enqueue(new ThreadRootsMarkingTask(p)); 4238 } 4239 q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread())); 4240} 4241#endif // INCLUDE_ALL_GCS 4242 4243void Threads::nmethods_do(CodeBlobClosure* cf) { 4244 ALL_JAVA_THREADS(p) { 4245 p->nmethods_do(cf); 4246 } 4247 VMThread::vm_thread()->nmethods_do(cf); 4248} 4249 4250void Threads::metadata_do(void f(Metadata*)) { 4251 ALL_JAVA_THREADS(p) { 4252 p->metadata_do(f); 4253 } 4254} 4255 4256class ThreadHandlesClosure : public ThreadClosure { 4257 void (*_f)(Metadata*); 4258 public: 4259 ThreadHandlesClosure(void f(Metadata*)) : _f(f) {} 4260 virtual void do_thread(Thread* thread) { 4261 thread->metadata_handles_do(_f); 4262 } 4263}; 4264 4265void Threads::metadata_handles_do(void f(Metadata*)) { 4266 // Only walk the Handles in Thread. 4267 ThreadHandlesClosure handles_closure(f); 4268 threads_do(&handles_closure); 4269} 4270 4271void Threads::deoptimized_wrt_marked_nmethods() { 4272 ALL_JAVA_THREADS(p) { 4273 p->deoptimized_wrt_marked_nmethods(); 4274 } 4275} 4276 4277 4278// Get count Java threads that are waiting to enter the specified monitor. 4279GrowableArray<JavaThread*>* Threads::get_pending_threads(int count, 4280 address monitor, 4281 bool doLock) { 4282 assert(doLock || SafepointSynchronize::is_at_safepoint(), 4283 "must grab Threads_lock or be at safepoint"); 4284 GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count); 4285 4286 int i = 0; 4287 { 4288 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4289 ALL_JAVA_THREADS(p) { 4290 if (!p->can_call_java()) continue; 4291 4292 address pending = (address)p->current_pending_monitor(); 4293 if (pending == monitor) { // found a match 4294 if (i < count) result->append(p); // save the first count matches 4295 i++; 4296 } 4297 } 4298 } 4299 return result; 4300} 4301 4302 4303JavaThread *Threads::owning_thread_from_monitor_owner(address owner, 4304 bool doLock) { 4305 assert(doLock || 4306 Threads_lock->owned_by_self() || 4307 SafepointSynchronize::is_at_safepoint(), 4308 "must grab Threads_lock or be at safepoint"); 4309 4310 // NULL owner means not locked so we can skip the search 4311 if (owner == NULL) return NULL; 4312 4313 { 4314 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4315 ALL_JAVA_THREADS(p) { 4316 // first, see if owner is the address of a Java thread 4317 if (owner == (address)p) return p; 4318 } 4319 } 4320 // Cannot assert on lack of success here since this function may be 4321 // used by code that is trying to report useful problem information 4322 // like deadlock detection. 4323 if (UseHeavyMonitors) return NULL; 4324 4325 // If we didn't find a matching Java thread and we didn't force use of 4326 // heavyweight monitors, then the owner is the stack address of the 4327 // Lock Word in the owning Java thread's stack. 4328 // 4329 JavaThread* the_owner = NULL; 4330 { 4331 MutexLockerEx ml(doLock ? Threads_lock : NULL); 4332 ALL_JAVA_THREADS(q) { 4333 if (q->is_lock_owned(owner)) { 4334 the_owner = q; 4335 break; 4336 } 4337 } 4338 } 4339 // cannot assert on lack of success here; see above comment 4340 return the_owner; 4341} 4342 4343// Threads::print_on() is called at safepoint by VM_PrintThreads operation. 4344void Threads::print_on(outputStream* st, bool print_stacks, 4345 bool internal_format, bool print_concurrent_locks) { 4346 char buf[32]; 4347 st->print_raw_cr(os::local_time_string(buf, sizeof(buf))); 4348 4349 st->print_cr("Full thread dump %s (%s %s):", 4350 Abstract_VM_Version::vm_name(), 4351 Abstract_VM_Version::vm_release(), 4352 Abstract_VM_Version::vm_info_string()); 4353 st->cr(); 4354 4355#if INCLUDE_SERVICES 4356 // Dump concurrent locks 4357 ConcurrentLocksDump concurrent_locks; 4358 if (print_concurrent_locks) { 4359 concurrent_locks.dump_at_safepoint(); 4360 } 4361#endif // INCLUDE_SERVICES 4362 4363 ALL_JAVA_THREADS(p) { 4364 ResourceMark rm; 4365 p->print_on(st); 4366 if (print_stacks) { 4367 if (internal_format) { 4368 p->trace_stack(); 4369 } else { 4370 p->print_stack_on(st); 4371 } 4372 } 4373 st->cr(); 4374#if INCLUDE_SERVICES 4375 if (print_concurrent_locks) { 4376 concurrent_locks.print_locks_on(p, st); 4377 } 4378#endif // INCLUDE_SERVICES 4379 } 4380 4381 VMThread::vm_thread()->print_on(st); 4382 st->cr(); 4383 Universe::heap()->print_gc_threads_on(st); 4384 WatcherThread* wt = WatcherThread::watcher_thread(); 4385 if (wt != NULL) { 4386 wt->print_on(st); 4387 st->cr(); 4388 } 4389 CompileBroker::print_compiler_threads_on(st); 4390 st->flush(); 4391} 4392 4393// Threads::print_on_error() is called by fatal error handler. It's possible 4394// that VM is not at safepoint and/or current thread is inside signal handler. 4395// Don't print stack trace, as the stack may not be walkable. Don't allocate 4396// memory (even in resource area), it might deadlock the error handler. 4397void Threads::print_on_error(outputStream* st, Thread* current, char* buf, 4398 int buflen) { 4399 bool found_current = false; 4400 st->print_cr("Java Threads: ( => current thread )"); 4401 ALL_JAVA_THREADS(thread) { 4402 bool is_current = (current == thread); 4403 found_current = found_current || is_current; 4404 4405 st->print("%s", is_current ? "=>" : " "); 4406 4407 st->print(PTR_FORMAT, p2i(thread)); 4408 st->print(" "); 4409 thread->print_on_error(st, buf, buflen); 4410 st->cr(); 4411 } 4412 st->cr(); 4413 4414 st->print_cr("Other Threads:"); 4415 if (VMThread::vm_thread()) { 4416 bool is_current = (current == VMThread::vm_thread()); 4417 found_current = found_current || is_current; 4418 st->print("%s", current == VMThread::vm_thread() ? "=>" : " "); 4419 4420 st->print(PTR_FORMAT, p2i(VMThread::vm_thread())); 4421 st->print(" "); 4422 VMThread::vm_thread()->print_on_error(st, buf, buflen); 4423 st->cr(); 4424 } 4425 WatcherThread* wt = WatcherThread::watcher_thread(); 4426 if (wt != NULL) { 4427 bool is_current = (current == wt); 4428 found_current = found_current || is_current; 4429 st->print("%s", is_current ? "=>" : " "); 4430 4431 st->print(PTR_FORMAT, p2i(wt)); 4432 st->print(" "); 4433 wt->print_on_error(st, buf, buflen); 4434 st->cr(); 4435 } 4436 if (!found_current) { 4437 st->cr(); 4438 st->print("=>" PTR_FORMAT " (exited) ", p2i(current)); 4439 current->print_on_error(st, buf, buflen); 4440 st->cr(); 4441 } 4442} 4443 4444// Internal SpinLock and Mutex 4445// Based on ParkEvent 4446 4447// Ad-hoc mutual exclusion primitives: SpinLock and Mux 4448// 4449// We employ SpinLocks _only for low-contention, fixed-length 4450// short-duration critical sections where we're concerned 4451// about native mutex_t or HotSpot Mutex:: latency. 4452// The mux construct provides a spin-then-block mutual exclusion 4453// mechanism. 4454// 4455// Testing has shown that contention on the ListLock guarding gFreeList 4456// is common. If we implement ListLock as a simple SpinLock it's common 4457// for the JVM to devolve to yielding with little progress. This is true 4458// despite the fact that the critical sections protected by ListLock are 4459// extremely short. 4460// 4461// TODO-FIXME: ListLock should be of type SpinLock. 4462// We should make this a 1st-class type, integrated into the lock 4463// hierarchy as leaf-locks. Critically, the SpinLock structure 4464// should have sufficient padding to avoid false-sharing and excessive 4465// cache-coherency traffic. 4466 4467 4468typedef volatile int SpinLockT; 4469 4470void Thread::SpinAcquire(volatile int * adr, const char * LockName) { 4471 if (Atomic::cmpxchg (1, adr, 0) == 0) { 4472 return; // normal fast-path return 4473 } 4474 4475 // Slow-path : We've encountered contention -- Spin/Yield/Block strategy. 4476 TEVENT(SpinAcquire - ctx); 4477 int ctr = 0; 4478 int Yields = 0; 4479 for (;;) { 4480 while (*adr != 0) { 4481 ++ctr; 4482 if ((ctr & 0xFFF) == 0 || !os::is_MP()) { 4483 if (Yields > 5) { 4484 os::naked_short_sleep(1); 4485 } else { 4486 os::naked_yield(); 4487 ++Yields; 4488 } 4489 } else { 4490 SpinPause(); 4491 } 4492 } 4493 if (Atomic::cmpxchg(1, adr, 0) == 0) return; 4494 } 4495} 4496 4497void Thread::SpinRelease(volatile int * adr) { 4498 assert(*adr != 0, "invariant"); 4499 OrderAccess::fence(); // guarantee at least release consistency. 4500 // Roach-motel semantics. 4501 // It's safe if subsequent LDs and STs float "up" into the critical section, 4502 // but prior LDs and STs within the critical section can't be allowed 4503 // to reorder or float past the ST that releases the lock. 4504 // Loads and stores in the critical section - which appear in program 4505 // order before the store that releases the lock - must also appear 4506 // before the store that releases the lock in memory visibility order. 4507 // Conceptually we need a #loadstore|#storestore "release" MEMBAR before 4508 // the ST of 0 into the lock-word which releases the lock, so fence 4509 // more than covers this on all platforms. 4510 *adr = 0; 4511} 4512 4513// muxAcquire and muxRelease: 4514// 4515// * muxAcquire and muxRelease support a single-word lock-word construct. 4516// The LSB of the word is set IFF the lock is held. 4517// The remainder of the word points to the head of a singly-linked list 4518// of threads blocked on the lock. 4519// 4520// * The current implementation of muxAcquire-muxRelease uses its own 4521// dedicated Thread._MuxEvent instance. If we're interested in 4522// minimizing the peak number of extant ParkEvent instances then 4523// we could eliminate _MuxEvent and "borrow" _ParkEvent as long 4524// as certain invariants were satisfied. Specifically, care would need 4525// to be taken with regards to consuming unpark() "permits". 4526// A safe rule of thumb is that a thread would never call muxAcquire() 4527// if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently 4528// park(). Otherwise the _ParkEvent park() operation in muxAcquire() could 4529// consume an unpark() permit intended for monitorenter, for instance. 4530// One way around this would be to widen the restricted-range semaphore 4531// implemented in park(). Another alternative would be to provide 4532// multiple instances of the PlatformEvent() for each thread. One 4533// instance would be dedicated to muxAcquire-muxRelease, for instance. 4534// 4535// * Usage: 4536// -- Only as leaf locks 4537// -- for short-term locking only as muxAcquire does not perform 4538// thread state transitions. 4539// 4540// Alternatives: 4541// * We could implement muxAcquire and muxRelease with MCS or CLH locks 4542// but with parking or spin-then-park instead of pure spinning. 4543// * Use Taura-Oyama-Yonenzawa locks. 4544// * It's possible to construct a 1-0 lock if we encode the lockword as 4545// (List,LockByte). Acquire will CAS the full lockword while Release 4546// will STB 0 into the LockByte. The 1-0 scheme admits stranding, so 4547// acquiring threads use timers (ParkTimed) to detect and recover from 4548// the stranding window. Thread/Node structures must be aligned on 256-byte 4549// boundaries by using placement-new. 4550// * Augment MCS with advisory back-link fields maintained with CAS(). 4551// Pictorially: LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner. 4552// The validity of the backlinks must be ratified before we trust the value. 4553// If the backlinks are invalid the exiting thread must back-track through the 4554// the forward links, which are always trustworthy. 4555// * Add a successor indication. The LockWord is currently encoded as 4556// (List, LOCKBIT:1). We could also add a SUCCBIT or an explicit _succ variable 4557// to provide the usual futile-wakeup optimization. 4558// See RTStt for details. 4559// * Consider schedctl.sc_nopreempt to cover the critical section. 4560// 4561 4562 4563typedef volatile intptr_t MutexT; // Mux Lock-word 4564enum MuxBits { LOCKBIT = 1 }; 4565 4566void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) { 4567 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4568 if (w == 0) return; 4569 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4570 return; 4571 } 4572 4573 TEVENT(muxAcquire - Contention); 4574 ParkEvent * const Self = Thread::current()->_MuxEvent; 4575 assert((intptr_t(Self) & LOCKBIT) == 0, "invariant"); 4576 for (;;) { 4577 int its = (os::is_MP() ? 100 : 0) + 1; 4578 4579 // Optional spin phase: spin-then-park strategy 4580 while (--its >= 0) { 4581 w = *Lock; 4582 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4583 return; 4584 } 4585 } 4586 4587 Self->reset(); 4588 Self->OnList = intptr_t(Lock); 4589 // The following fence() isn't _strictly necessary as the subsequent 4590 // CAS() both serializes execution and ratifies the fetched *Lock value. 4591 OrderAccess::fence(); 4592 for (;;) { 4593 w = *Lock; 4594 if ((w & LOCKBIT) == 0) { 4595 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4596 Self->OnList = 0; // hygiene - allows stronger asserts 4597 return; 4598 } 4599 continue; // Interference -- *Lock changed -- Just retry 4600 } 4601 assert(w & LOCKBIT, "invariant"); 4602 Self->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4603 if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break; 4604 } 4605 4606 while (Self->OnList != 0) { 4607 Self->park(); 4608 } 4609 } 4610} 4611 4612void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) { 4613 intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0); 4614 if (w == 0) return; 4615 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4616 return; 4617 } 4618 4619 TEVENT(muxAcquire - Contention); 4620 ParkEvent * ReleaseAfter = NULL; 4621 if (ev == NULL) { 4622 ev = ReleaseAfter = ParkEvent::Allocate(NULL); 4623 } 4624 assert((intptr_t(ev) & LOCKBIT) == 0, "invariant"); 4625 for (;;) { 4626 guarantee(ev->OnList == 0, "invariant"); 4627 int its = (os::is_MP() ? 100 : 0) + 1; 4628 4629 // Optional spin phase: spin-then-park strategy 4630 while (--its >= 0) { 4631 w = *Lock; 4632 if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4633 if (ReleaseAfter != NULL) { 4634 ParkEvent::Release(ReleaseAfter); 4635 } 4636 return; 4637 } 4638 } 4639 4640 ev->reset(); 4641 ev->OnList = intptr_t(Lock); 4642 // The following fence() isn't _strictly necessary as the subsequent 4643 // CAS() both serializes execution and ratifies the fetched *Lock value. 4644 OrderAccess::fence(); 4645 for (;;) { 4646 w = *Lock; 4647 if ((w & LOCKBIT) == 0) { 4648 if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) { 4649 ev->OnList = 0; 4650 // We call ::Release while holding the outer lock, thus 4651 // artificially lengthening the critical section. 4652 // Consider deferring the ::Release() until the subsequent unlock(), 4653 // after we've dropped the outer lock. 4654 if (ReleaseAfter != NULL) { 4655 ParkEvent::Release(ReleaseAfter); 4656 } 4657 return; 4658 } 4659 continue; // Interference -- *Lock changed -- Just retry 4660 } 4661 assert(w & LOCKBIT, "invariant"); 4662 ev->ListNext = (ParkEvent *) (w & ~LOCKBIT); 4663 if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break; 4664 } 4665 4666 while (ev->OnList != 0) { 4667 ev->park(); 4668 } 4669 } 4670} 4671 4672// Release() must extract a successor from the list and then wake that thread. 4673// It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme 4674// similar to that used by ParkEvent::Allocate() and ::Release(). DMR-based 4675// Release() would : 4676// (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list. 4677// (B) Extract a successor from the private list "in-hand" 4678// (C) attempt to CAS() the residual back into *Lock over null. 4679// If there were any newly arrived threads and the CAS() would fail. 4680// In that case Release() would detach the RATs, re-merge the list in-hand 4681// with the RATs and repeat as needed. Alternately, Release() might 4682// detach and extract a successor, but then pass the residual list to the wakee. 4683// The wakee would be responsible for reattaching and remerging before it 4684// competed for the lock. 4685// 4686// Both "pop" and DMR are immune from ABA corruption -- there can be 4687// multiple concurrent pushers, but only one popper or detacher. 4688// This implementation pops from the head of the list. This is unfair, 4689// but tends to provide excellent throughput as hot threads remain hot. 4690// (We wake recently run threads first). 4691// 4692// All paths through muxRelease() will execute a CAS. 4693// Release consistency -- We depend on the CAS in muxRelease() to provide full 4694// bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations 4695// executed within the critical section are complete and globally visible before the 4696// store (CAS) to the lock-word that releases the lock becomes globally visible. 4697void Thread::muxRelease(volatile intptr_t * Lock) { 4698 for (;;) { 4699 const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT); 4700 assert(w & LOCKBIT, "invariant"); 4701 if (w == LOCKBIT) return; 4702 ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT); 4703 assert(List != NULL, "invariant"); 4704 assert(List->OnList == intptr_t(Lock), "invariant"); 4705 ParkEvent * const nxt = List->ListNext; 4706 guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant"); 4707 4708 // The following CAS() releases the lock and pops the head element. 4709 // The CAS() also ratifies the previously fetched lock-word value. 4710 if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) { 4711 continue; 4712 } 4713 List->OnList = 0; 4714 OrderAccess::fence(); 4715 List->unpark(); 4716 return; 4717 } 4718} 4719 4720 4721void Threads::verify() { 4722 ALL_JAVA_THREADS(p) { 4723 p->verify(); 4724 } 4725 VMThread* thread = VMThread::vm_thread(); 4726 if (thread != NULL) thread->verify(); 4727} 4728