threadService.cpp revision 3465:d2a62e0f25eb
1/* 2 * Copyright (c) 2003, 2011, 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/systemDictionary.hpp" 27#include "memory/allocation.hpp" 28#include "memory/heapInspection.hpp" 29#include "memory/oopFactory.hpp" 30#include "oops/instanceKlass.hpp" 31#include "oops/oop.inline.hpp" 32#include "runtime/handles.inline.hpp" 33#include "runtime/init.hpp" 34#include "runtime/thread.hpp" 35#include "runtime/vframe.hpp" 36#include "runtime/vmThread.hpp" 37#include "runtime/vm_operations.hpp" 38#include "services/threadService.hpp" 39 40// TODO: we need to define a naming convention for perf counters 41// to distinguish counters for: 42// - standard JSR174 use 43// - Hotspot extension (public and committed) 44// - Hotspot extension (private/internal and uncommitted) 45 46// Default is disabled. 47bool ThreadService::_thread_monitoring_contention_enabled = false; 48bool ThreadService::_thread_cpu_time_enabled = false; 49bool ThreadService::_thread_allocated_memory_enabled = false; 50 51PerfCounter* ThreadService::_total_threads_count = NULL; 52PerfVariable* ThreadService::_live_threads_count = NULL; 53PerfVariable* ThreadService::_peak_threads_count = NULL; 54PerfVariable* ThreadService::_daemon_threads_count = NULL; 55volatile int ThreadService::_exiting_threads_count = 0; 56volatile int ThreadService::_exiting_daemon_threads_count = 0; 57 58ThreadDumpResult* ThreadService::_threaddump_list = NULL; 59 60static const int INITIAL_ARRAY_SIZE = 10; 61 62void ThreadService::init() { 63 EXCEPTION_MARK; 64 65 // These counters are for java.lang.management API support. 66 // They are created even if -XX:-UsePerfData is set and in 67 // that case, they will be allocated on C heap. 68 69 _total_threads_count = 70 PerfDataManager::create_counter(JAVA_THREADS, "started", 71 PerfData::U_Events, CHECK); 72 73 _live_threads_count = 74 PerfDataManager::create_variable(JAVA_THREADS, "live", 75 PerfData::U_None, CHECK); 76 77 _peak_threads_count = 78 PerfDataManager::create_variable(JAVA_THREADS, "livePeak", 79 PerfData::U_None, CHECK); 80 81 _daemon_threads_count = 82 PerfDataManager::create_variable(JAVA_THREADS, "daemon", 83 PerfData::U_None, CHECK); 84 85 if (os::is_thread_cpu_time_supported()) { 86 _thread_cpu_time_enabled = true; 87 } 88 89 _thread_allocated_memory_enabled = true; // Always on, so enable it 90} 91 92void ThreadService::reset_peak_thread_count() { 93 // Acquire the lock to update the peak thread count 94 // to synchronize with thread addition and removal. 95 MutexLockerEx mu(Threads_lock); 96 _peak_threads_count->set_value(get_live_thread_count()); 97} 98 99void ThreadService::add_thread(JavaThread* thread, bool daemon) { 100 // Do not count VM internal or JVMTI agent threads 101 if (thread->is_hidden_from_external_view() || 102 thread->is_jvmti_agent_thread()) { 103 return; 104 } 105 106 _total_threads_count->inc(); 107 _live_threads_count->inc(); 108 109 if (_live_threads_count->get_value() > _peak_threads_count->get_value()) { 110 _peak_threads_count->set_value(_live_threads_count->get_value()); 111 } 112 113 if (daemon) { 114 _daemon_threads_count->inc(); 115 } 116} 117 118void ThreadService::remove_thread(JavaThread* thread, bool daemon) { 119 Atomic::dec((jint*) &_exiting_threads_count); 120 121 if (thread->is_hidden_from_external_view() || 122 thread->is_jvmti_agent_thread()) { 123 return; 124 } 125 126 _live_threads_count->set_value(_live_threads_count->get_value() - 1); 127 128 if (daemon) { 129 _daemon_threads_count->set_value(_daemon_threads_count->get_value() - 1); 130 Atomic::dec((jint*) &_exiting_daemon_threads_count); 131 } 132} 133 134void ThreadService::current_thread_exiting(JavaThread* jt) { 135 assert(jt == JavaThread::current(), "Called by current thread"); 136 Atomic::inc((jint*) &_exiting_threads_count); 137 138 oop threadObj = jt->threadObj(); 139 if (threadObj != NULL && java_lang_Thread::is_daemon(threadObj)) { 140 Atomic::inc((jint*) &_exiting_daemon_threads_count); 141 } 142} 143 144// FIXME: JVMTI should call this function 145Handle ThreadService::get_current_contended_monitor(JavaThread* thread) { 146 assert(thread != NULL, "should be non-NULL"); 147 assert(Threads_lock->owned_by_self(), "must grab Threads_lock or be at safepoint"); 148 149 ObjectMonitor *wait_obj = thread->current_waiting_monitor(); 150 151 oop obj = NULL; 152 if (wait_obj != NULL) { 153 // thread is doing an Object.wait() call 154 obj = (oop) wait_obj->object(); 155 assert(obj != NULL, "Object.wait() should have an object"); 156 } else { 157 ObjectMonitor *enter_obj = thread->current_pending_monitor(); 158 if (enter_obj != NULL) { 159 // thread is trying to enter() or raw_enter() an ObjectMonitor. 160 obj = (oop) enter_obj->object(); 161 } 162 // If obj == NULL, then ObjectMonitor is raw which doesn't count. 163 } 164 165 Handle h(obj); 166 return h; 167} 168 169bool ThreadService::set_thread_monitoring_contention(bool flag) { 170 MutexLocker m(Management_lock); 171 172 bool prev = _thread_monitoring_contention_enabled; 173 _thread_monitoring_contention_enabled = flag; 174 175 return prev; 176} 177 178bool ThreadService::set_thread_cpu_time_enabled(bool flag) { 179 MutexLocker m(Management_lock); 180 181 bool prev = _thread_cpu_time_enabled; 182 _thread_cpu_time_enabled = flag; 183 184 return prev; 185} 186 187bool ThreadService::set_thread_allocated_memory_enabled(bool flag) { 188 MutexLocker m(Management_lock); 189 190 bool prev = _thread_allocated_memory_enabled; 191 _thread_allocated_memory_enabled = flag; 192 193 return prev; 194} 195 196// GC support 197void ThreadService::oops_do(OopClosure* f) { 198 for (ThreadDumpResult* dump = _threaddump_list; dump != NULL; dump = dump->next()) { 199 dump->oops_do(f); 200 } 201} 202 203void ThreadService::add_thread_dump(ThreadDumpResult* dump) { 204 MutexLocker ml(Management_lock); 205 if (_threaddump_list == NULL) { 206 _threaddump_list = dump; 207 } else { 208 dump->set_next(_threaddump_list); 209 _threaddump_list = dump; 210 } 211} 212 213void ThreadService::remove_thread_dump(ThreadDumpResult* dump) { 214 MutexLocker ml(Management_lock); 215 216 ThreadDumpResult* prev = NULL; 217 bool found = false; 218 for (ThreadDumpResult* d = _threaddump_list; d != NULL; prev = d, d = d->next()) { 219 if (d == dump) { 220 if (prev == NULL) { 221 _threaddump_list = dump->next(); 222 } else { 223 prev->set_next(dump->next()); 224 } 225 found = true; 226 break; 227 } 228 } 229 assert(found, "The threaddump result to be removed must exist."); 230} 231 232// Dump stack trace of threads specified in the given threads array. 233// Returns StackTraceElement[][] each element is the stack trace of a thread in 234// the corresponding entry in the given threads array 235Handle ThreadService::dump_stack_traces(GrowableArray<instanceHandle>* threads, 236 int num_threads, 237 TRAPS) { 238 assert(num_threads > 0, "just checking"); 239 240 ThreadDumpResult dump_result; 241 VM_ThreadDump op(&dump_result, 242 threads, 243 num_threads, 244 -1, /* entire stack */ 245 false, /* with locked monitors */ 246 false /* with locked synchronizers */); 247 VMThread::execute(&op); 248 249 // Allocate the resulting StackTraceElement[][] object 250 251 ResourceMark rm(THREAD); 252 klassOop k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_StackTraceElement_array(), true, CHECK_NH); 253 objArrayKlassHandle ik (THREAD, k); 254 objArrayOop r = oopFactory::new_objArray(ik(), num_threads, CHECK_NH); 255 objArrayHandle result_obj(THREAD, r); 256 257 int num_snapshots = dump_result.num_snapshots(); 258 assert(num_snapshots == num_threads, "Must have num_threads thread snapshots"); 259 int i = 0; 260 for (ThreadSnapshot* ts = dump_result.snapshots(); ts != NULL; i++, ts = ts->next()) { 261 ThreadStackTrace* stacktrace = ts->get_stack_trace(); 262 if (stacktrace == NULL) { 263 // No stack trace 264 result_obj->obj_at_put(i, NULL); 265 } else { 266 // Construct an array of java/lang/StackTraceElement object 267 Handle backtrace_h = stacktrace->allocate_fill_stack_trace_element_array(CHECK_NH); 268 result_obj->obj_at_put(i, backtrace_h()); 269 } 270 } 271 272 return result_obj; 273} 274 275void ThreadService::reset_contention_count_stat(JavaThread* thread) { 276 ThreadStatistics* stat = thread->get_thread_stat(); 277 if (stat != NULL) { 278 stat->reset_count_stat(); 279 } 280} 281 282void ThreadService::reset_contention_time_stat(JavaThread* thread) { 283 ThreadStatistics* stat = thread->get_thread_stat(); 284 if (stat != NULL) { 285 stat->reset_time_stat(); 286 } 287} 288 289// Find deadlocks involving object monitors and concurrent locks if concurrent_locks is true 290DeadlockCycle* ThreadService::find_deadlocks_at_safepoint(bool concurrent_locks) { 291 // This code was modified from the original Threads::find_deadlocks code. 292 int globalDfn = 0, thisDfn; 293 ObjectMonitor* waitingToLockMonitor = NULL; 294 oop waitingToLockBlocker = NULL; 295 bool blocked_on_monitor = false; 296 JavaThread *currentThread, *previousThread; 297 int num_deadlocks = 0; 298 299 for (JavaThread* p = Threads::first(); p != NULL; p = p->next()) { 300 // Initialize the depth-first-number 301 p->set_depth_first_number(-1); 302 } 303 304 DeadlockCycle* deadlocks = NULL; 305 DeadlockCycle* last = NULL; 306 DeadlockCycle* cycle = new DeadlockCycle(); 307 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) { 308 if (jt->depth_first_number() >= 0) { 309 // this thread was already visited 310 continue; 311 } 312 313 thisDfn = globalDfn; 314 jt->set_depth_first_number(globalDfn++); 315 previousThread = jt; 316 currentThread = jt; 317 318 cycle->reset(); 319 320 // When there is a deadlock, all the monitors involved in the dependency 321 // cycle must be contended and heavyweight. So we only care about the 322 // heavyweight monitor a thread is waiting to lock. 323 waitingToLockMonitor = (ObjectMonitor*)jt->current_pending_monitor(); 324 if (concurrent_locks) { 325 waitingToLockBlocker = jt->current_park_blocker(); 326 } 327 while (waitingToLockMonitor != NULL || waitingToLockBlocker != NULL) { 328 cycle->add_thread(currentThread); 329 if (waitingToLockMonitor != NULL) { 330 currentThread = Threads::owning_thread_from_monitor_owner((address)waitingToLockMonitor->owner(), 331 false /* no locking needed */); 332 } else { 333 if (concurrent_locks) { 334 if (waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) { 335 oop threadObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker); 336 currentThread = threadObj != NULL ? java_lang_Thread::thread(threadObj) : NULL; 337 } else { 338 currentThread = NULL; 339 } 340 } 341 } 342 343 if (currentThread == NULL) { 344 // No dependency on another thread 345 break; 346 } 347 if (currentThread->depth_first_number() < 0) { 348 // First visit to this thread 349 currentThread->set_depth_first_number(globalDfn++); 350 } else if (currentThread->depth_first_number() < thisDfn) { 351 // Thread already visited, and not on a (new) cycle 352 break; 353 } else if (currentThread == previousThread) { 354 // Self-loop, ignore 355 break; 356 } else { 357 // We have a (new) cycle 358 num_deadlocks++; 359 360 cycle->set_deadlock(true); 361 362 // add this cycle to the deadlocks list 363 if (deadlocks == NULL) { 364 deadlocks = cycle; 365 } else { 366 last->set_next(cycle); 367 } 368 last = cycle; 369 cycle = new DeadlockCycle(); 370 break; 371 } 372 previousThread = currentThread; 373 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor(); 374 if (concurrent_locks) { 375 waitingToLockBlocker = currentThread->current_park_blocker(); 376 } 377 } 378 379 } 380 delete cycle; 381 return deadlocks; 382} 383 384ThreadDumpResult::ThreadDumpResult() : _num_threads(0), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) { 385 386 // Create a new ThreadDumpResult object and append to the list. 387 // If GC happens before this function returns, methodOop 388 // in the stack trace will be visited. 389 ThreadService::add_thread_dump(this); 390} 391 392ThreadDumpResult::ThreadDumpResult(int num_threads) : _num_threads(num_threads), _num_snapshots(0), _snapshots(NULL), _next(NULL), _last(NULL) { 393 // Create a new ThreadDumpResult object and append to the list. 394 // If GC happens before this function returns, oops 395 // will be visited. 396 ThreadService::add_thread_dump(this); 397} 398 399ThreadDumpResult::~ThreadDumpResult() { 400 ThreadService::remove_thread_dump(this); 401 402 // free all the ThreadSnapshot objects created during 403 // the VM_ThreadDump operation 404 ThreadSnapshot* ts = _snapshots; 405 while (ts != NULL) { 406 ThreadSnapshot* p = ts; 407 ts = ts->next(); 408 delete p; 409 } 410} 411 412 413void ThreadDumpResult::add_thread_snapshot(ThreadSnapshot* ts) { 414 assert(_num_threads == 0 || _num_snapshots < _num_threads, 415 "_num_snapshots must be less than _num_threads"); 416 _num_snapshots++; 417 if (_snapshots == NULL) { 418 _snapshots = ts; 419 } else { 420 _last->set_next(ts); 421 } 422 _last = ts; 423} 424 425void ThreadDumpResult::oops_do(OopClosure* f) { 426 for (ThreadSnapshot* ts = _snapshots; ts != NULL; ts = ts->next()) { 427 ts->oops_do(f); 428 } 429} 430 431StackFrameInfo::StackFrameInfo(javaVFrame* jvf, bool with_lock_info) { 432 _method = jvf->method(); 433 _bci = jvf->bci(); 434 _locked_monitors = NULL; 435 if (with_lock_info) { 436 ResourceMark rm; 437 GrowableArray<MonitorInfo*>* list = jvf->locked_monitors(); 438 int length = list->length(); 439 if (length > 0) { 440 _locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(length, true); 441 for (int i = 0; i < length; i++) { 442 MonitorInfo* monitor = list->at(i); 443 assert(monitor->owner(), "This monitor must have an owning object"); 444 _locked_monitors->append(monitor->owner()); 445 } 446 } 447 } 448} 449 450void StackFrameInfo::oops_do(OopClosure* f) { 451 f->do_oop((oop*) &_method); 452 if (_locked_monitors != NULL) { 453 int length = _locked_monitors->length(); 454 for (int i = 0; i < length; i++) { 455 f->do_oop((oop*) _locked_monitors->adr_at(i)); 456 } 457 } 458} 459 460void StackFrameInfo::print_on(outputStream* st) const { 461 ResourceMark rm; 462 java_lang_Throwable::print_stack_element(st, method(), bci()); 463 int len = (_locked_monitors != NULL ? _locked_monitors->length() : 0); 464 for (int i = 0; i < len; i++) { 465 oop o = _locked_monitors->at(i); 466 instanceKlass* ik = instanceKlass::cast(o->klass()); 467 st->print_cr("\t- locked <" INTPTR_FORMAT "> (a %s)", (address)o, ik->external_name()); 468 } 469 470} 471 472// Iterate through monitor cache to find JNI locked monitors 473class InflatedMonitorsClosure: public MonitorClosure { 474private: 475 ThreadStackTrace* _stack_trace; 476 Thread* _thread; 477public: 478 InflatedMonitorsClosure(Thread* t, ThreadStackTrace* st) { 479 _thread = t; 480 _stack_trace = st; 481 } 482 void do_monitor(ObjectMonitor* mid) { 483 if (mid->owner() == _thread) { 484 oop object = (oop) mid->object(); 485 if (!_stack_trace->is_owned_monitor_on_stack(object)) { 486 _stack_trace->add_jni_locked_monitor(object); 487 } 488 } 489 } 490}; 491 492ThreadStackTrace::ThreadStackTrace(JavaThread* t, bool with_locked_monitors) { 493 _thread = t; 494 _frames = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<StackFrameInfo*>(INITIAL_ARRAY_SIZE, true); 495 _depth = 0; 496 _with_locked_monitors = with_locked_monitors; 497 if (_with_locked_monitors) { 498 _jni_locked_monitors = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(INITIAL_ARRAY_SIZE, true); 499 } else { 500 _jni_locked_monitors = NULL; 501 } 502} 503 504ThreadStackTrace::~ThreadStackTrace() { 505 for (int i = 0; i < _frames->length(); i++) { 506 delete _frames->at(i); 507 } 508 delete _frames; 509 if (_jni_locked_monitors != NULL) { 510 delete _jni_locked_monitors; 511 } 512} 513 514void ThreadStackTrace::dump_stack_at_safepoint(int maxDepth) { 515 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 516 517 if (_thread->has_last_Java_frame()) { 518 RegisterMap reg_map(_thread); 519 vframe* start_vf = _thread->last_java_vframe(®_map); 520 int count = 0; 521 for (vframe* f = start_vf; f; f = f->sender() ) { 522 if (f->is_java_frame()) { 523 javaVFrame* jvf = javaVFrame::cast(f); 524 add_stack_frame(jvf); 525 count++; 526 } else { 527 // Ignore non-Java frames 528 } 529 if (maxDepth > 0 && count == maxDepth) { 530 // Skip frames if more than maxDepth 531 break; 532 } 533 } 534 } 535 536 if (_with_locked_monitors) { 537 // Iterate inflated monitors and find monitors locked by this thread 538 // not found in the stack 539 InflatedMonitorsClosure imc(_thread, this); 540 ObjectSynchronizer::monitors_iterate(&imc); 541 } 542} 543 544 545bool ThreadStackTrace::is_owned_monitor_on_stack(oop object) { 546 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 547 548 bool found = false; 549 int num_frames = get_stack_depth(); 550 for (int depth = 0; depth < num_frames; depth++) { 551 StackFrameInfo* frame = stack_frame_at(depth); 552 int len = frame->num_locked_monitors(); 553 GrowableArray<oop>* locked_monitors = frame->locked_monitors(); 554 for (int j = 0; j < len; j++) { 555 oop monitor = locked_monitors->at(j); 556 assert(monitor != NULL && monitor->is_instance(), "must be a Java object"); 557 if (monitor == object) { 558 found = true; 559 break; 560 } 561 } 562 } 563 return found; 564} 565 566Handle ThreadStackTrace::allocate_fill_stack_trace_element_array(TRAPS) { 567 klassOop k = SystemDictionary::StackTraceElement_klass(); 568 assert(k != NULL, "must be loaded in 1.4+"); 569 instanceKlassHandle ik(THREAD, k); 570 571 // Allocate an array of java/lang/StackTraceElement object 572 objArrayOop ste = oopFactory::new_objArray(ik(), _depth, CHECK_NH); 573 objArrayHandle backtrace(THREAD, ste); 574 for (int j = 0; j < _depth; j++) { 575 StackFrameInfo* frame = _frames->at(j); 576 methodHandle mh(THREAD, frame->method()); 577 oop element = java_lang_StackTraceElement::create(mh, frame->bci(), CHECK_NH); 578 backtrace->obj_at_put(j, element); 579 } 580 return backtrace; 581} 582 583void ThreadStackTrace::add_stack_frame(javaVFrame* jvf) { 584 StackFrameInfo* frame = new StackFrameInfo(jvf, _with_locked_monitors); 585 _frames->append(frame); 586 _depth++; 587} 588 589void ThreadStackTrace::oops_do(OopClosure* f) { 590 int length = _frames->length(); 591 for (int i = 0; i < length; i++) { 592 _frames->at(i)->oops_do(f); 593 } 594 595 length = (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0); 596 for (int j = 0; j < length; j++) { 597 f->do_oop((oop*) _jni_locked_monitors->adr_at(j)); 598 } 599} 600 601ConcurrentLocksDump::~ConcurrentLocksDump() { 602 if (_retain_map_on_free) { 603 return; 604 } 605 606 for (ThreadConcurrentLocks* t = _map; t != NULL;) { 607 ThreadConcurrentLocks* tcl = t; 608 t = t->next(); 609 delete tcl; 610 } 611} 612 613void ConcurrentLocksDump::dump_at_safepoint() { 614 // dump all locked concurrent locks 615 assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped"); 616 617 if (JDK_Version::is_gte_jdk16x_version()) { 618 ResourceMark rm; 619 620 GrowableArray<oop>* aos_objects = new GrowableArray<oop>(INITIAL_ARRAY_SIZE); 621 622 // Find all instances of AbstractOwnableSynchronizer 623 HeapInspection::find_instances_at_safepoint(SystemDictionary::abstract_ownable_synchronizer_klass(), 624 aos_objects); 625 // Build a map of thread to its owned AQS locks 626 build_map(aos_objects); 627 } 628} 629 630 631// build a map of JavaThread to all its owned AbstractOwnableSynchronizer 632void ConcurrentLocksDump::build_map(GrowableArray<oop>* aos_objects) { 633 int length = aos_objects->length(); 634 for (int i = 0; i < length; i++) { 635 oop o = aos_objects->at(i); 636 oop owner_thread_obj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(o); 637 if (owner_thread_obj != NULL) { 638 JavaThread* thread = java_lang_Thread::thread(owner_thread_obj); 639 assert(o->is_instance(), "Must be an instanceOop"); 640 add_lock(thread, (instanceOop) o); 641 } 642 } 643} 644 645void ConcurrentLocksDump::add_lock(JavaThread* thread, instanceOop o) { 646 ThreadConcurrentLocks* tcl = thread_concurrent_locks(thread); 647 if (tcl != NULL) { 648 tcl->add_lock(o); 649 return; 650 } 651 652 // First owned lock found for this thread 653 tcl = new ThreadConcurrentLocks(thread); 654 tcl->add_lock(o); 655 if (_map == NULL) { 656 _map = tcl; 657 } else { 658 _last->set_next(tcl); 659 } 660 _last = tcl; 661} 662 663ThreadConcurrentLocks* ConcurrentLocksDump::thread_concurrent_locks(JavaThread* thread) { 664 for (ThreadConcurrentLocks* tcl = _map; tcl != NULL; tcl = tcl->next()) { 665 if (tcl->java_thread() == thread) { 666 return tcl; 667 } 668 } 669 return NULL; 670} 671 672void ConcurrentLocksDump::print_locks_on(JavaThread* t, outputStream* st) { 673 st->print_cr(" Locked ownable synchronizers:"); 674 ThreadConcurrentLocks* tcl = thread_concurrent_locks(t); 675 GrowableArray<instanceOop>* locks = (tcl != NULL ? tcl->owned_locks() : NULL); 676 if (locks == NULL || locks->is_empty()) { 677 st->print_cr("\t- None"); 678 st->cr(); 679 return; 680 } 681 682 for (int i = 0; i < locks->length(); i++) { 683 instanceOop obj = locks->at(i); 684 instanceKlass* ik = instanceKlass::cast(obj->klass()); 685 st->print_cr("\t- <" INTPTR_FORMAT "> (a %s)", (address)obj, ik->external_name()); 686 } 687 st->cr(); 688} 689 690ThreadConcurrentLocks::ThreadConcurrentLocks(JavaThread* thread) { 691 _thread = thread; 692 _owned_locks = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<instanceOop>(INITIAL_ARRAY_SIZE, true); 693 _next = NULL; 694} 695 696ThreadConcurrentLocks::~ThreadConcurrentLocks() { 697 delete _owned_locks; 698} 699 700void ThreadConcurrentLocks::add_lock(instanceOop o) { 701 _owned_locks->append(o); 702} 703 704void ThreadConcurrentLocks::oops_do(OopClosure* f) { 705 int length = _owned_locks->length(); 706 for (int i = 0; i < length; i++) { 707 f->do_oop((oop*) _owned_locks->adr_at(i)); 708 } 709} 710 711ThreadStatistics::ThreadStatistics() { 712 _contended_enter_count = 0; 713 _monitor_wait_count = 0; 714 _sleep_count = 0; 715 _count_pending_reset = false; 716 _timer_pending_reset = false; 717 memset((void*) _perf_recursion_counts, 0, sizeof(_perf_recursion_counts)); 718} 719 720ThreadSnapshot::ThreadSnapshot(JavaThread* thread) { 721 _thread = thread; 722 _threadObj = thread->threadObj(); 723 _stack_trace = NULL; 724 _concurrent_locks = NULL; 725 _next = NULL; 726 727 ThreadStatistics* stat = thread->get_thread_stat(); 728 _contended_enter_ticks = stat->contended_enter_ticks(); 729 _contended_enter_count = stat->contended_enter_count(); 730 _monitor_wait_ticks = stat->monitor_wait_ticks(); 731 _monitor_wait_count = stat->monitor_wait_count(); 732 _sleep_ticks = stat->sleep_ticks(); 733 _sleep_count = stat->sleep_count(); 734 735 _blocker_object = NULL; 736 _blocker_object_owner = NULL; 737 738 _thread_status = java_lang_Thread::get_thread_status(_threadObj); 739 _is_ext_suspended = thread->is_being_ext_suspended(); 740 _is_in_native = (thread->thread_state() == _thread_in_native); 741 742 if (_thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER || 743 _thread_status == java_lang_Thread::IN_OBJECT_WAIT || 744 _thread_status == java_lang_Thread::IN_OBJECT_WAIT_TIMED) { 745 746 Handle obj = ThreadService::get_current_contended_monitor(thread); 747 if (obj() == NULL) { 748 // monitor no longer exists; thread is not blocked 749 _thread_status = java_lang_Thread::RUNNABLE; 750 } else { 751 _blocker_object = obj(); 752 JavaThread* owner = ObjectSynchronizer::get_lock_owner(obj, false); 753 if ((owner == NULL && _thread_status == java_lang_Thread::BLOCKED_ON_MONITOR_ENTER) 754 || (owner != NULL && owner->is_attaching_via_jni())) { 755 // ownership information of the monitor is not available 756 // (may no longer be owned or releasing to some other thread) 757 // make this thread in RUNNABLE state. 758 // And when the owner thread is in attaching state, the java thread 759 // is not completely initialized. For example thread name and id 760 // and may not be set, so hide the attaching thread. 761 _thread_status = java_lang_Thread::RUNNABLE; 762 _blocker_object = NULL; 763 } else if (owner != NULL) { 764 _blocker_object_owner = owner->threadObj(); 765 } 766 } 767 } 768 769 // Support for JSR-166 locks 770 if (JDK_Version::current().supports_thread_park_blocker() && 771 (_thread_status == java_lang_Thread::PARKED || 772 _thread_status == java_lang_Thread::PARKED_TIMED)) { 773 774 _blocker_object = thread->current_park_blocker(); 775 if (_blocker_object != NULL && _blocker_object->is_a(SystemDictionary::abstract_ownable_synchronizer_klass())) { 776 _blocker_object_owner = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(_blocker_object); 777 } 778 } 779} 780 781ThreadSnapshot::~ThreadSnapshot() { 782 delete _stack_trace; 783 delete _concurrent_locks; 784} 785 786void ThreadSnapshot::dump_stack_at_safepoint(int max_depth, bool with_locked_monitors) { 787 _stack_trace = new ThreadStackTrace(_thread, with_locked_monitors); 788 _stack_trace->dump_stack_at_safepoint(max_depth); 789} 790 791 792void ThreadSnapshot::oops_do(OopClosure* f) { 793 f->do_oop(&_threadObj); 794 f->do_oop(&_blocker_object); 795 f->do_oop(&_blocker_object_owner); 796 if (_stack_trace != NULL) { 797 _stack_trace->oops_do(f); 798 } 799 if (_concurrent_locks != NULL) { 800 _concurrent_locks->oops_do(f); 801 } 802} 803 804DeadlockCycle::DeadlockCycle() { 805 _is_deadlock = false; 806 _threads = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<JavaThread*>(INITIAL_ARRAY_SIZE, true); 807 _next = NULL; 808} 809 810DeadlockCycle::~DeadlockCycle() { 811 delete _threads; 812} 813 814void DeadlockCycle::print_on(outputStream* st) const { 815 st->cr(); 816 st->print_cr("Found one Java-level deadlock:"); 817 st->print("============================="); 818 819 JavaThread* currentThread; 820 ObjectMonitor* waitingToLockMonitor; 821 oop waitingToLockBlocker; 822 int len = _threads->length(); 823 for (int i = 0; i < len; i++) { 824 currentThread = _threads->at(i); 825 waitingToLockMonitor = (ObjectMonitor*)currentThread->current_pending_monitor(); 826 waitingToLockBlocker = currentThread->current_park_blocker(); 827 st->cr(); 828 st->print_cr("\"%s\":", currentThread->get_thread_name()); 829 const char* owner_desc = ",\n which is held by"; 830 if (waitingToLockMonitor != NULL) { 831 st->print(" waiting to lock monitor " INTPTR_FORMAT, waitingToLockMonitor); 832 oop obj = (oop)waitingToLockMonitor->object(); 833 if (obj != NULL) { 834 st->print(" (object "INTPTR_FORMAT ", a %s)", (address)obj, 835 (instanceKlass::cast(obj->klass()))->external_name()); 836 837 if (!currentThread->current_pending_monitor_is_from_java()) { 838 owner_desc = "\n in JNI, which is held by"; 839 } 840 } else { 841 // No Java object associated - a JVMTI raw monitor 842 owner_desc = " (JVMTI raw monitor),\n which is held by"; 843 } 844 currentThread = Threads::owning_thread_from_monitor_owner( 845 (address)waitingToLockMonitor->owner(), false /* no locking needed */); 846 } else { 847 st->print(" waiting for ownable synchronizer " INTPTR_FORMAT ", (a %s)", 848 (address)waitingToLockBlocker, 849 (instanceKlass::cast(waitingToLockBlocker->klass()))->external_name()); 850 assert(waitingToLockBlocker->is_a(SystemDictionary::abstract_ownable_synchronizer_klass()), 851 "Must be an AbstractOwnableSynchronizer"); 852 oop ownerObj = java_util_concurrent_locks_AbstractOwnableSynchronizer::get_owner_threadObj(waitingToLockBlocker); 853 currentThread = java_lang_Thread::thread(ownerObj); 854 } 855 st->print("%s \"%s\"", owner_desc, currentThread->get_thread_name()); 856 } 857 858 st->cr(); 859 st->cr(); 860 861 // Print stack traces 862 bool oldJavaMonitorsInStackTrace = JavaMonitorsInStackTrace; 863 JavaMonitorsInStackTrace = true; 864 st->print_cr("Java stack information for the threads listed above:"); 865 st->print_cr("==================================================="); 866 for (int j = 0; j < len; j++) { 867 currentThread = _threads->at(j); 868 st->print_cr("\"%s\":", currentThread->get_thread_name()); 869 currentThread->print_stack_on(st); 870 } 871 JavaMonitorsInStackTrace = oldJavaMonitorsInStackTrace; 872} 873 874ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread, 875 bool include_jvmti_agent_threads, 876 bool include_jni_attaching_threads) { 877 assert(cur_thread == Thread::current(), "Check current thread"); 878 879 int init_size = ThreadService::get_live_thread_count(); 880 _threads_array = new GrowableArray<instanceHandle>(init_size); 881 882 MutexLockerEx ml(Threads_lock); 883 884 for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) { 885 // skips JavaThreads in the process of exiting 886 // and also skips VM internal JavaThreads 887 // Threads in _thread_new or _thread_new_trans state are included. 888 // i.e. threads have been started but not yet running. 889 if (jt->threadObj() == NULL || 890 jt->is_exiting() || 891 !java_lang_Thread::is_alive(jt->threadObj()) || 892 jt->is_hidden_from_external_view()) { 893 continue; 894 } 895 896 // skip agent threads 897 if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) { 898 continue; 899 } 900 901 // skip jni threads in the process of attaching 902 if (!include_jni_attaching_threads && jt->is_attaching_via_jni()) { 903 continue; 904 } 905 906 instanceHandle h(cur_thread, (instanceOop) jt->threadObj()); 907 _threads_array->append(h); 908 } 909} 910