safepoint.cpp revision 605:98cb887364d3
1/* 2 * Copyright 1997-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25# include "incls/_precompiled.incl" 26# include "incls/_safepoint.cpp.incl" 27 28// -------------------------------------------------------------------------------------------------- 29// Implementation of Safepoint begin/end 30 31SafepointSynchronize::SynchronizeState volatile SafepointSynchronize::_state = SafepointSynchronize::_not_synchronized; 32volatile int SafepointSynchronize::_waiting_to_block = 0; 33jlong SafepointSynchronize::_last_safepoint = 0; 34volatile int SafepointSynchronize::_safepoint_counter = 0; 35static volatile int PageArmed = 0 ; // safepoint polling page is RO|RW vs PROT_NONE 36static volatile int TryingToBlock = 0 ; // proximate value -- for advisory use only 37static bool timeout_error_printed = false; 38 39// Roll all threads forward to a safepoint and suspend them all 40void SafepointSynchronize::begin() { 41 42 Thread* myThread = Thread::current(); 43 assert(myThread->is_VM_thread(), "Only VM thread may execute a safepoint"); 44 45 _last_safepoint = os::javaTimeNanos(); 46 47#ifndef SERIALGC 48 if (UseConcMarkSweepGC) { 49 // In the future we should investigate whether CMS can use the 50 // more-general mechanism below. DLD (01/05). 51 ConcurrentMarkSweepThread::synchronize(false); 52 } else { 53 ConcurrentGCThread::safepoint_synchronize(); 54 } 55#endif // SERIALGC 56 57 // By getting the Threads_lock, we assure that no threads are about to start or 58 // exit. It is released again in SafepointSynchronize::end(). 59 Threads_lock->lock(); 60 61 assert( _state == _not_synchronized, "trying to safepoint synchronize with wrong state"); 62 63 int nof_threads = Threads::number_of_threads(); 64 65 if (TraceSafepoint) { 66 tty->print_cr("Safepoint synchronization initiated. (%d)", nof_threads); 67 } 68 69 RuntimeService::record_safepoint_begin(); 70 71 { 72 MutexLocker mu(Safepoint_lock); 73 74 // Set number of threads to wait for, before we initiate the callbacks 75 _waiting_to_block = nof_threads; 76 TryingToBlock = 0 ; 77 int still_running = nof_threads; 78 79 // Save the starting time, so that it can be compared to see if this has taken 80 // too long to complete. 81 jlong safepoint_limit_time; 82 timeout_error_printed = false; 83 84 // Begin the process of bringing the system to a safepoint. 85 // Java threads can be in several different states and are 86 // stopped by different mechanisms: 87 // 88 // 1. Running interpreted 89 // The interpeter dispatch table is changed to force it to 90 // check for a safepoint condition between bytecodes. 91 // 2. Running in native code 92 // When returning from the native code, a Java thread must check 93 // the safepoint _state to see if we must block. If the 94 // VM thread sees a Java thread in native, it does 95 // not wait for this thread to block. The order of the memory 96 // writes and reads of both the safepoint state and the Java 97 // threads state is critical. In order to guarantee that the 98 // memory writes are serialized with respect to each other, 99 // the VM thread issues a memory barrier instruction 100 // (on MP systems). In order to avoid the overhead of issuing 101 // a memory barrier for each Java thread making native calls, each Java 102 // thread performs a write to a single memory page after changing 103 // the thread state. The VM thread performs a sequence of 104 // mprotect OS calls which forces all previous writes from all 105 // Java threads to be serialized. This is done in the 106 // os::serialize_thread_states() call. This has proven to be 107 // much more efficient than executing a membar instruction 108 // on every call to native code. 109 // 3. Running compiled Code 110 // Compiled code reads a global (Safepoint Polling) page that 111 // is set to fault if we are trying to get to a safepoint. 112 // 4. Blocked 113 // A thread which is blocked will not be allowed to return from the 114 // block condition until the safepoint operation is complete. 115 // 5. In VM or Transitioning between states 116 // If a Java thread is currently running in the VM or transitioning 117 // between states, the safepointing code will wait for the thread to 118 // block itself when it attempts transitions to a new state. 119 // 120 _state = _synchronizing; 121 OrderAccess::fence(); 122 123 // Flush all thread states to memory 124 if (!UseMembar) { 125 os::serialize_thread_states(); 126 } 127 128 // Make interpreter safepoint aware 129 Interpreter::notice_safepoints(); 130 131 if (UseCompilerSafepoints && DeferPollingPageLoopCount < 0) { 132 // Make polling safepoint aware 133 guarantee (PageArmed == 0, "invariant") ; 134 PageArmed = 1 ; 135 os::make_polling_page_unreadable(); 136 } 137 138 // Consider using active_processor_count() ... but that call is expensive. 139 int ncpus = os::processor_count() ; 140 141#ifdef ASSERT 142 for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) { 143 assert(cur->safepoint_state()->is_running(), "Illegal initial state"); 144 } 145#endif // ASSERT 146 147 if (SafepointTimeout) 148 safepoint_limit_time = os::javaTimeNanos() + (jlong)SafepointTimeoutDelay * MICROUNITS; 149 150 // Iterate through all threads until it have been determined how to stop them all at a safepoint 151 unsigned int iterations = 0; 152 int steps = 0 ; 153 while(still_running > 0) { 154 for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) { 155 assert(!cur->is_ConcurrentGC_thread(), "A concurrent GC thread is unexpectly being suspended"); 156 ThreadSafepointState *cur_state = cur->safepoint_state(); 157 if (cur_state->is_running()) { 158 cur_state->examine_state_of_thread(); 159 if (!cur_state->is_running()) { 160 still_running--; 161 // consider adjusting steps downward: 162 // steps = 0 163 // steps -= NNN 164 // steps >>= 1 165 // steps = MIN(steps, 2000-100) 166 // if (iterations != 0) steps -= NNN 167 } 168 if (TraceSafepoint && Verbose) cur_state->print(); 169 } 170 } 171 172 if ( (PrintSafepointStatistics || (PrintSafepointStatisticsTimeout > 0)) 173 && iterations == 0) { 174 begin_statistics(nof_threads, still_running); 175 } 176 177 if (still_running > 0) { 178 // Check for if it takes to long 179 if (SafepointTimeout && safepoint_limit_time < os::javaTimeNanos()) { 180 print_safepoint_timeout(_spinning_timeout); 181 } 182 183 // Spin to avoid context switching. 184 // There's a tension between allowing the mutators to run (and rendezvous) 185 // vs spinning. As the VM thread spins, wasting cycles, it consumes CPU that 186 // a mutator might otherwise use profitably to reach a safepoint. Excessive 187 // spinning by the VM thread on a saturated system can increase rendezvous latency. 188 // Blocking or yielding incur their own penalties in the form of context switching 189 // and the resultant loss of $ residency. 190 // 191 // Further complicating matters is that yield() does not work as naively expected 192 // on many platforms -- yield() does not guarantee that any other ready threads 193 // will run. As such we revert yield_all() after some number of iterations. 194 // Yield_all() is implemented as a short unconditional sleep on some platforms. 195 // Typical operating systems round a "short" sleep period up to 10 msecs, so sleeping 196 // can actually increase the time it takes the VM thread to detect that a system-wide 197 // stop-the-world safepoint has been reached. In a pathological scenario such as that 198 // described in CR6415670 the VMthread may sleep just before the mutator(s) become safe. 199 // In that case the mutators will be stalled waiting for the safepoint to complete and the 200 // the VMthread will be sleeping, waiting for the mutators to rendezvous. The VMthread 201 // will eventually wake up and detect that all mutators are safe, at which point 202 // we'll again make progress. 203 // 204 // Beware too that that the VMThread typically runs at elevated priority. 205 // Its default priority is higher than the default mutator priority. 206 // Obviously, this complicates spinning. 207 // 208 // Note too that on Windows XP SwitchThreadTo() has quite different behavior than Sleep(0). 209 // Sleep(0) will _not yield to lower priority threads, while SwitchThreadTo() will. 210 // 211 // See the comments in synchronizer.cpp for additional remarks on spinning. 212 // 213 // In the future we might: 214 // 1. Modify the safepoint scheme to avoid potentally unbounded spinning. 215 // This is tricky as the path used by a thread exiting the JVM (say on 216 // on JNI call-out) simply stores into its state field. The burden 217 // is placed on the VM thread, which must poll (spin). 218 // 2. Find something useful to do while spinning. If the safepoint is GC-related 219 // we might aggressively scan the stacks of threads that are already safe. 220 // 3. Use Solaris schedctl to examine the state of the still-running mutators. 221 // If all the mutators are ONPROC there's no reason to sleep or yield. 222 // 4. YieldTo() any still-running mutators that are ready but OFFPROC. 223 // 5. Check system saturation. If the system is not fully saturated then 224 // simply spin and avoid sleep/yield. 225 // 6. As still-running mutators rendezvous they could unpark the sleeping 226 // VMthread. This works well for still-running mutators that become 227 // safe. The VMthread must still poll for mutators that call-out. 228 // 7. Drive the policy on time-since-begin instead of iterations. 229 // 8. Consider making the spin duration a function of the # of CPUs: 230 // Spin = (((ncpus-1) * M) + K) + F(still_running) 231 // Alternately, instead of counting iterations of the outer loop 232 // we could count the # of threads visited in the inner loop, above. 233 // 9. On windows consider using the return value from SwitchThreadTo() 234 // to drive subsequent spin/SwitchThreadTo()/Sleep(N) decisions. 235 236 if (UseCompilerSafepoints && int(iterations) == DeferPollingPageLoopCount) { 237 guarantee (PageArmed == 0, "invariant") ; 238 PageArmed = 1 ; 239 os::make_polling_page_unreadable(); 240 } 241 242 // Instead of (ncpus > 1) consider either (still_running < (ncpus + EPSILON)) or 243 // ((still_running + _waiting_to_block - TryingToBlock)) < ncpus) 244 ++steps ; 245 if (ncpus > 1 && steps < SafepointSpinBeforeYield) { 246 SpinPause() ; // MP-Polite spin 247 } else 248 if (steps < DeferThrSuspendLoopCount) { 249 os::NakedYield() ; 250 } else { 251 os::yield_all(steps) ; 252 // Alternately, the VM thread could transiently depress its scheduling priority or 253 // transiently increase the priority of the tardy mutator(s). 254 } 255 256 iterations ++ ; 257 } 258 assert(iterations < (uint)max_jint, "We have been iterating in the safepoint loop too long"); 259 } 260 assert(still_running == 0, "sanity check"); 261 262 if (PrintSafepointStatistics) { 263 update_statistics_on_spin_end(); 264 } 265 266 // wait until all threads are stopped 267 while (_waiting_to_block > 0) { 268 if (TraceSafepoint) tty->print_cr("Waiting for %d thread(s) to block", _waiting_to_block); 269 if (!SafepointTimeout || timeout_error_printed) { 270 Safepoint_lock->wait(true); // true, means with no safepoint checks 271 } else { 272 // Compute remaining time 273 jlong remaining_time = safepoint_limit_time - os::javaTimeNanos(); 274 275 // If there is no remaining time, then there is an error 276 if (remaining_time < 0 || Safepoint_lock->wait(true, remaining_time / MICROUNITS)) { 277 print_safepoint_timeout(_blocking_timeout); 278 } 279 } 280 } 281 assert(_waiting_to_block == 0, "sanity check"); 282 283#ifndef PRODUCT 284 if (SafepointTimeout) { 285 jlong current_time = os::javaTimeNanos(); 286 if (safepoint_limit_time < current_time) { 287 tty->print_cr("# SafepointSynchronize: Finished after " 288 INT64_FORMAT_W(6) " ms", 289 ((current_time - safepoint_limit_time) / MICROUNITS + 290 SafepointTimeoutDelay)); 291 } 292 } 293#endif 294 295 assert((_safepoint_counter & 0x1) == 0, "must be even"); 296 assert(Threads_lock->owned_by_self(), "must hold Threads_lock"); 297 _safepoint_counter ++; 298 299 // Record state 300 _state = _synchronized; 301 302 OrderAccess::fence(); 303 304 if (TraceSafepoint) { 305 VM_Operation *op = VMThread::vm_operation(); 306 tty->print_cr("Entering safepoint region: %s", (op != NULL) ? op->name() : "no vm operation"); 307 } 308 309 RuntimeService::record_safepoint_synchronized(); 310 if (PrintSafepointStatistics) { 311 update_statistics_on_sync_end(os::javaTimeNanos()); 312 } 313 314 // Call stuff that needs to be run when a safepoint is just about to be completed 315 do_cleanup_tasks(); 316 } 317} 318 319// Wake up all threads, so they are ready to resume execution after the safepoint 320// operation has been carried out 321void SafepointSynchronize::end() { 322 323 assert(Threads_lock->owned_by_self(), "must hold Threads_lock"); 324 assert((_safepoint_counter & 0x1) == 1, "must be odd"); 325 _safepoint_counter ++; 326 // memory fence isn't required here since an odd _safepoint_counter 327 // value can do no harm and a fence is issued below anyway. 328 329 DEBUG_ONLY(Thread* myThread = Thread::current();) 330 assert(myThread->is_VM_thread(), "Only VM thread can execute a safepoint"); 331 332 if (PrintSafepointStatistics) { 333 end_statistics(os::javaTimeNanos()); 334 } 335 336#ifdef ASSERT 337 // A pending_exception cannot be installed during a safepoint. The threads 338 // may install an async exception after they come back from a safepoint into 339 // pending_exception after they unblock. But that should happen later. 340 for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) { 341 assert (!(cur->has_pending_exception() && 342 cur->safepoint_state()->is_at_poll_safepoint()), 343 "safepoint installed a pending exception"); 344 } 345#endif // ASSERT 346 347 if (PageArmed) { 348 // Make polling safepoint aware 349 os::make_polling_page_readable(); 350 PageArmed = 0 ; 351 } 352 353 // Remove safepoint check from interpreter 354 Interpreter::ignore_safepoints(); 355 356 { 357 MutexLocker mu(Safepoint_lock); 358 359 assert(_state == _synchronized, "must be synchronized before ending safepoint synchronization"); 360 361 // Set to not synchronized, so the threads will not go into the signal_thread_blocked method 362 // when they get restarted. 363 _state = _not_synchronized; 364 OrderAccess::fence(); 365 366 if (TraceSafepoint) { 367 tty->print_cr("Leaving safepoint region"); 368 } 369 370 // Start suspended threads 371 for(JavaThread *current = Threads::first(); current; current = current->next()) { 372 // A problem occurring on Solaris is when attempting to restart threads 373 // the first #cpus - 1 go well, but then the VMThread is preempted when we get 374 // to the next one (since it has been running the longest). We then have 375 // to wait for a cpu to become available before we can continue restarting 376 // threads. 377 // FIXME: This causes the performance of the VM to degrade when active and with 378 // large numbers of threads. Apparently this is due to the synchronous nature 379 // of suspending threads. 380 // 381 // TODO-FIXME: the comments above are vestigial and no longer apply. 382 // Furthermore, using solaris' schedctl in this particular context confers no benefit 383 if (VMThreadHintNoPreempt) { 384 os::hint_no_preempt(); 385 } 386 ThreadSafepointState* cur_state = current->safepoint_state(); 387 assert(cur_state->type() != ThreadSafepointState::_running, "Thread not suspended at safepoint"); 388 cur_state->restart(); 389 assert(cur_state->is_running(), "safepoint state has not been reset"); 390 } 391 392 RuntimeService::record_safepoint_end(); 393 394 // Release threads lock, so threads can be created/destroyed again. It will also starts all threads 395 // blocked in signal_thread_blocked 396 Threads_lock->unlock(); 397 398 } 399#ifndef SERIALGC 400 // If there are any concurrent GC threads resume them. 401 if (UseConcMarkSweepGC) { 402 ConcurrentMarkSweepThread::desynchronize(false); 403 } else { 404 ConcurrentGCThread::safepoint_desynchronize(); 405 } 406#endif // SERIALGC 407} 408 409bool SafepointSynchronize::is_cleanup_needed() { 410 // Need a safepoint if some inline cache buffers is non-empty 411 if (!InlineCacheBuffer::is_empty()) return true; 412 return false; 413} 414 415jlong CounterDecay::_last_timestamp = 0; 416 417static void do_method(methodOop m) { 418 m->invocation_counter()->decay(); 419} 420 421void CounterDecay::decay() { 422 _last_timestamp = os::javaTimeMillis(); 423 424 // This operation is going to be performed only at the end of a safepoint 425 // and hence GC's will not be going on, all Java mutators are suspended 426 // at this point and hence SystemDictionary_lock is also not needed. 427 assert(SafepointSynchronize::is_at_safepoint(), "can only be executed at a safepoint"); 428 int nclasses = SystemDictionary::number_of_classes(); 429 double classes_per_tick = nclasses * (CounterDecayMinIntervalLength * 1e-3 / 430 CounterHalfLifeTime); 431 for (int i = 0; i < classes_per_tick; i++) { 432 klassOop k = SystemDictionary::try_get_next_class(); 433 if (k != NULL && k->klass_part()->oop_is_instance()) { 434 instanceKlass::cast(k)->methods_do(do_method); 435 } 436 } 437} 438 439// Various cleaning tasks that should be done periodically at safepoints 440void SafepointSynchronize::do_cleanup_tasks() { 441 jlong cleanup_time; 442 443 // Update fat-monitor pool, since this is a safepoint. 444 if (TraceSafepoint) { 445 cleanup_time = os::javaTimeNanos(); 446 } 447 448 ObjectSynchronizer::deflate_idle_monitors(); 449 InlineCacheBuffer::update_inline_caches(); 450 if(UseCounterDecay && CounterDecay::is_decay_needed()) { 451 CounterDecay::decay(); 452 } 453 NMethodSweeper::sweep(); 454 455 if (TraceSafepoint) { 456 tty->print_cr("do_cleanup_tasks takes "INT64_FORMAT_W(6) "ms", 457 (os::javaTimeNanos() - cleanup_time) / MICROUNITS); 458 } 459} 460 461 462bool SafepointSynchronize::safepoint_safe(JavaThread *thread, JavaThreadState state) { 463 switch(state) { 464 case _thread_in_native: 465 // native threads are safe if they have no java stack or have walkable stack 466 return !thread->has_last_Java_frame() || thread->frame_anchor()->walkable(); 467 468 // blocked threads should have already have walkable stack 469 case _thread_blocked: 470 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "blocked and not walkable"); 471 return true; 472 473 default: 474 return false; 475 } 476} 477 478 479// ------------------------------------------------------------------------------------------------------- 480// Implementation of Safepoint callback point 481 482void SafepointSynchronize::block(JavaThread *thread) { 483 assert(thread != NULL, "thread must be set"); 484 assert(thread->is_Java_thread(), "not a Java thread"); 485 486 // Threads shouldn't block if they are in the middle of printing, but... 487 ttyLocker::break_tty_lock_for_safepoint(os::current_thread_id()); 488 489 // Only bail from the block() call if the thread is gone from the 490 // thread list; starting to exit should still block. 491 if (thread->is_terminated()) { 492 // block current thread if we come here from native code when VM is gone 493 thread->block_if_vm_exited(); 494 495 // otherwise do nothing 496 return; 497 } 498 499 JavaThreadState state = thread->thread_state(); 500 thread->frame_anchor()->make_walkable(thread); 501 502 // Check that we have a valid thread_state at this point 503 switch(state) { 504 case _thread_in_vm_trans: 505 case _thread_in_Java: // From compiled code 506 507 // We are highly likely to block on the Safepoint_lock. In order to avoid blocking in this case, 508 // we pretend we are still in the VM. 509 thread->set_thread_state(_thread_in_vm); 510 511 if (is_synchronizing()) { 512 Atomic::inc (&TryingToBlock) ; 513 } 514 515 // We will always be holding the Safepoint_lock when we are examine the state 516 // of a thread. Hence, the instructions between the Safepoint_lock->lock() and 517 // Safepoint_lock->unlock() are happening atomic with regards to the safepoint code 518 Safepoint_lock->lock_without_safepoint_check(); 519 if (is_synchronizing()) { 520 // Decrement the number of threads to wait for and signal vm thread 521 assert(_waiting_to_block > 0, "sanity check"); 522 _waiting_to_block--; 523 thread->safepoint_state()->set_has_called_back(true); 524 525 // Consider (_waiting_to_block < 2) to pipeline the wakeup of the VM thread 526 if (_waiting_to_block == 0) { 527 Safepoint_lock->notify_all(); 528 } 529 } 530 531 // We transition the thread to state _thread_blocked here, but 532 // we can't do our usual check for external suspension and then 533 // self-suspend after the lock_without_safepoint_check() call 534 // below because we are often called during transitions while 535 // we hold different locks. That would leave us suspended while 536 // holding a resource which results in deadlocks. 537 thread->set_thread_state(_thread_blocked); 538 Safepoint_lock->unlock(); 539 540 // We now try to acquire the threads lock. Since this lock is hold by the VM thread during 541 // the entire safepoint, the threads will all line up here during the safepoint. 542 Threads_lock->lock_without_safepoint_check(); 543 // restore original state. This is important if the thread comes from compiled code, so it 544 // will continue to execute with the _thread_in_Java state. 545 thread->set_thread_state(state); 546 Threads_lock->unlock(); 547 break; 548 549 case _thread_in_native_trans: 550 case _thread_blocked_trans: 551 case _thread_new_trans: 552 if (thread->safepoint_state()->type() == ThreadSafepointState::_call_back) { 553 thread->print_thread_state(); 554 fatal("Deadlock in safepoint code. " 555 "Should have called back to the VM before blocking."); 556 } 557 558 // We transition the thread to state _thread_blocked here, but 559 // we can't do our usual check for external suspension and then 560 // self-suspend after the lock_without_safepoint_check() call 561 // below because we are often called during transitions while 562 // we hold different locks. That would leave us suspended while 563 // holding a resource which results in deadlocks. 564 thread->set_thread_state(_thread_blocked); 565 566 // It is not safe to suspend a thread if we discover it is in _thread_in_native_trans. Hence, 567 // the safepoint code might still be waiting for it to block. We need to change the state here, 568 // so it can see that it is at a safepoint. 569 570 // Block until the safepoint operation is completed. 571 Threads_lock->lock_without_safepoint_check(); 572 573 // Restore state 574 thread->set_thread_state(state); 575 576 Threads_lock->unlock(); 577 break; 578 579 default: 580 fatal1("Illegal threadstate encountered: %d", state); 581 } 582 583 // Check for pending. async. exceptions or suspends - except if the 584 // thread was blocked inside the VM. has_special_runtime_exit_condition() 585 // is called last since it grabs a lock and we only want to do that when 586 // we must. 587 // 588 // Note: we never deliver an async exception at a polling point as the 589 // compiler may not have an exception handler for it. The polling 590 // code will notice the async and deoptimize and the exception will 591 // be delivered. (Polling at a return point is ok though). Sure is 592 // a lot of bother for a deprecated feature... 593 // 594 // We don't deliver an async exception if the thread state is 595 // _thread_in_native_trans so JNI functions won't be called with 596 // a surprising pending exception. If the thread state is going back to java, 597 // async exception is checked in check_special_condition_for_native_trans(). 598 599 if (state != _thread_blocked_trans && 600 state != _thread_in_vm_trans && 601 thread->has_special_runtime_exit_condition()) { 602 thread->handle_special_runtime_exit_condition( 603 !thread->is_at_poll_safepoint() && (state != _thread_in_native_trans)); 604 } 605} 606 607// ------------------------------------------------------------------------------------------------------ 608// Exception handlers 609 610#ifndef PRODUCT 611#ifdef _LP64 612#define PTR_PAD "" 613#else 614#define PTR_PAD " " 615#endif 616 617static void print_ptrs(intptr_t oldptr, intptr_t newptr, bool wasoop) { 618 bool is_oop = newptr ? ((oop)newptr)->is_oop() : false; 619 tty->print_cr(PTR_FORMAT PTR_PAD " %s %c " PTR_FORMAT PTR_PAD " %s %s", 620 oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!', 621 newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" ")); 622} 623 624static void print_longs(jlong oldptr, jlong newptr, bool wasoop) { 625 bool is_oop = newptr ? ((oop)(intptr_t)newptr)->is_oop() : false; 626 tty->print_cr(PTR64_FORMAT " %s %c " PTR64_FORMAT " %s %s", 627 oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!', 628 newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" ")); 629} 630 631#ifdef SPARC 632static void print_me(intptr_t *new_sp, intptr_t *old_sp, bool *was_oops) { 633#ifdef _LP64 634 tty->print_cr("--------+------address-----+------before-----------+-------after----------+"); 635 const int incr = 1; // Increment to skip a long, in units of intptr_t 636#else 637 tty->print_cr("--------+--address-+------before-----------+-------after----------+"); 638 const int incr = 2; // Increment to skip a long, in units of intptr_t 639#endif 640 tty->print_cr("---SP---|"); 641 for( int i=0; i<16; i++ ) { 642 tty->print("blob %c%d |"PTR_FORMAT" ","LO"[i>>3],i&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); } 643 tty->print_cr("--------|"); 644 for( int i1=0; i1<frame::memory_parameter_word_sp_offset-16; i1++ ) { 645 tty->print("argv pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); } 646 tty->print(" pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); 647 tty->print_cr("--------|"); 648 tty->print(" G1 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr; 649 tty->print(" G3 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr; 650 tty->print(" G4 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr; 651 tty->print(" G5 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr; 652 tty->print_cr(" FSR |"PTR_FORMAT" "PTR64_FORMAT" "PTR64_FORMAT,new_sp,*(jlong*)old_sp,*(jlong*)new_sp); 653 old_sp += incr; new_sp += incr; was_oops += incr; 654 // Skip the floats 655 tty->print_cr("--Float-|"PTR_FORMAT,new_sp); 656 tty->print_cr("---FP---|"); 657 old_sp += incr*32; new_sp += incr*32; was_oops += incr*32; 658 for( int i2=0; i2<16; i2++ ) { 659 tty->print("call %c%d |"PTR_FORMAT" ","LI"[i2>>3],i2&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); } 660 tty->print_cr(""); 661} 662#endif // SPARC 663#endif // PRODUCT 664 665 666void SafepointSynchronize::handle_polling_page_exception(JavaThread *thread) { 667 assert(thread->is_Java_thread(), "polling reference encountered by VM thread"); 668 assert(thread->thread_state() == _thread_in_Java, "should come from Java code"); 669 assert(SafepointSynchronize::is_synchronizing(), "polling encountered outside safepoint synchronization"); 670 671 // Uncomment this to get some serious before/after printing of the 672 // Sparc safepoint-blob frame structure. 673 /* 674 intptr_t* sp = thread->last_Java_sp(); 675 intptr_t stack_copy[150]; 676 for( int i=0; i<150; i++ ) stack_copy[i] = sp[i]; 677 bool was_oops[150]; 678 for( int i=0; i<150; i++ ) 679 was_oops[i] = stack_copy[i] ? ((oop)stack_copy[i])->is_oop() : false; 680 */ 681 682 if (ShowSafepointMsgs) { 683 tty->print("handle_polling_page_exception: "); 684 } 685 686 if (PrintSafepointStatistics) { 687 inc_page_trap_count(); 688 } 689 690 ThreadSafepointState* state = thread->safepoint_state(); 691 692 state->handle_polling_page_exception(); 693 // print_me(sp,stack_copy,was_oops); 694} 695 696 697void SafepointSynchronize::print_safepoint_timeout(SafepointTimeoutReason reason) { 698 if (!timeout_error_printed) { 699 timeout_error_printed = true; 700 // Print out the thread infor which didn't reach the safepoint for debugging 701 // purposes (useful when there are lots of threads in the debugger). 702 tty->print_cr(""); 703 tty->print_cr("# SafepointSynchronize::begin: Timeout detected:"); 704 if (reason == _spinning_timeout) { 705 tty->print_cr("# SafepointSynchronize::begin: Timed out while spinning to reach a safepoint."); 706 } else if (reason == _blocking_timeout) { 707 tty->print_cr("# SafepointSynchronize::begin: Timed out while waiting for threads to stop."); 708 } 709 710 tty->print_cr("# SafepointSynchronize::begin: Threads which did not reach the safepoint:"); 711 ThreadSafepointState *cur_state; 712 ResourceMark rm; 713 for(JavaThread *cur_thread = Threads::first(); cur_thread; 714 cur_thread = cur_thread->next()) { 715 cur_state = cur_thread->safepoint_state(); 716 717 if (cur_thread->thread_state() != _thread_blocked && 718 ((reason == _spinning_timeout && cur_state->is_running()) || 719 (reason == _blocking_timeout && !cur_state->has_called_back()))) { 720 tty->print("# "); 721 cur_thread->print(); 722 tty->print_cr(""); 723 } 724 } 725 tty->print_cr("# SafepointSynchronize::begin: (End of list)"); 726 } 727 728 // To debug the long safepoint, specify both DieOnSafepointTimeout & 729 // ShowMessageBoxOnError. 730 if (DieOnSafepointTimeout) { 731 char msg[1024]; 732 VM_Operation *op = VMThread::vm_operation(); 733 sprintf(msg, "Safepoint sync time longer than " INTX_FORMAT "ms detected when executing %s.", 734 SafepointTimeoutDelay, 735 op != NULL ? op->name() : "no vm operation"); 736 fatal(msg); 737 } 738} 739 740 741// ------------------------------------------------------------------------------------------------------- 742// Implementation of ThreadSafepointState 743 744ThreadSafepointState::ThreadSafepointState(JavaThread *thread) { 745 _thread = thread; 746 _type = _running; 747 _has_called_back = false; 748 _at_poll_safepoint = false; 749} 750 751void ThreadSafepointState::create(JavaThread *thread) { 752 ThreadSafepointState *state = new ThreadSafepointState(thread); 753 thread->set_safepoint_state(state); 754} 755 756void ThreadSafepointState::destroy(JavaThread *thread) { 757 if (thread->safepoint_state()) { 758 delete(thread->safepoint_state()); 759 thread->set_safepoint_state(NULL); 760 } 761} 762 763void ThreadSafepointState::examine_state_of_thread() { 764 assert(is_running(), "better be running or just have hit safepoint poll"); 765 766 JavaThreadState state = _thread->thread_state(); 767 768 // Check for a thread that is suspended. Note that thread resume tries 769 // to grab the Threads_lock which we own here, so a thread cannot be 770 // resumed during safepoint synchronization. 771 772 // We check with locking because another thread that has not yet 773 // synchronized may be trying to suspend this one. 774 bool is_suspended = _thread->is_any_suspended_with_lock(); 775 if (is_suspended) { 776 roll_forward(_at_safepoint); 777 return; 778 } 779 780 // Some JavaThread states have an initial safepoint state of 781 // running, but are actually at a safepoint. We will happily 782 // agree and update the safepoint state here. 783 if (SafepointSynchronize::safepoint_safe(_thread, state)) { 784 roll_forward(_at_safepoint); 785 return; 786 } 787 788 if (state == _thread_in_vm) { 789 roll_forward(_call_back); 790 return; 791 } 792 793 // All other thread states will continue to run until they 794 // transition and self-block in state _blocked 795 // Safepoint polling in compiled code causes the Java threads to do the same. 796 // Note: new threads may require a malloc so they must be allowed to finish 797 798 assert(is_running(), "examine_state_of_thread on non-running thread"); 799 return; 800} 801 802// Returns true is thread could not be rolled forward at present position. 803void ThreadSafepointState::roll_forward(suspend_type type) { 804 _type = type; 805 806 switch(_type) { 807 case _at_safepoint: 808 SafepointSynchronize::signal_thread_at_safepoint(); 809 break; 810 811 case _call_back: 812 set_has_called_back(false); 813 break; 814 815 case _running: 816 default: 817 ShouldNotReachHere(); 818 } 819} 820 821void ThreadSafepointState::restart() { 822 switch(type()) { 823 case _at_safepoint: 824 case _call_back: 825 break; 826 827 case _running: 828 default: 829 tty->print_cr("restart thread "INTPTR_FORMAT" with state %d", 830 _thread, _type); 831 _thread->print(); 832 ShouldNotReachHere(); 833 } 834 _type = _running; 835 set_has_called_back(false); 836} 837 838 839void ThreadSafepointState::print_on(outputStream *st) const { 840 const char *s; 841 842 switch(_type) { 843 case _running : s = "_running"; break; 844 case _at_safepoint : s = "_at_safepoint"; break; 845 case _call_back : s = "_call_back"; break; 846 default: 847 ShouldNotReachHere(); 848 } 849 850 st->print_cr("Thread: " INTPTR_FORMAT 851 " [0x%2x] State: %s _has_called_back %d _at_poll_safepoint %d", 852 _thread, _thread->osthread()->thread_id(), s, _has_called_back, 853 _at_poll_safepoint); 854 855 _thread->print_thread_state_on(st); 856} 857 858 859// --------------------------------------------------------------------------------------------------------------------- 860 861// Block the thread at the safepoint poll or poll return. 862void ThreadSafepointState::handle_polling_page_exception() { 863 864 // Check state. block() will set thread state to thread_in_vm which will 865 // cause the safepoint state _type to become _call_back. 866 assert(type() == ThreadSafepointState::_running, 867 "polling page exception on thread not running state"); 868 869 // Step 1: Find the nmethod from the return address 870 if (ShowSafepointMsgs && Verbose) { 871 tty->print_cr("Polling page exception at " INTPTR_FORMAT, thread()->saved_exception_pc()); 872 } 873 address real_return_addr = thread()->saved_exception_pc(); 874 875 CodeBlob *cb = CodeCache::find_blob(real_return_addr); 876 assert(cb != NULL && cb->is_nmethod(), "return address should be in nmethod"); 877 nmethod* nm = (nmethod*)cb; 878 879 // Find frame of caller 880 frame stub_fr = thread()->last_frame(); 881 CodeBlob* stub_cb = stub_fr.cb(); 882 assert(stub_cb->is_safepoint_stub(), "must be a safepoint stub"); 883 RegisterMap map(thread(), true); 884 frame caller_fr = stub_fr.sender(&map); 885 886 // Should only be poll_return or poll 887 assert( nm->is_at_poll_or_poll_return(real_return_addr), "should not be at call" ); 888 889 // This is a poll immediately before a return. The exception handling code 890 // has already had the effect of causing the return to occur, so the execution 891 // will continue immediately after the call. In addition, the oopmap at the 892 // return point does not mark the return value as an oop (if it is), so 893 // it needs a handle here to be updated. 894 if( nm->is_at_poll_return(real_return_addr) ) { 895 // See if return type is an oop. 896 bool return_oop = nm->method()->is_returning_oop(); 897 Handle return_value; 898 if (return_oop) { 899 // The oop result has been saved on the stack together with all 900 // the other registers. In order to preserve it over GCs we need 901 // to keep it in a handle. 902 oop result = caller_fr.saved_oop_result(&map); 903 assert(result == NULL || result->is_oop(), "must be oop"); 904 return_value = Handle(thread(), result); 905 assert(Universe::heap()->is_in_or_null(result), "must be heap pointer"); 906 } 907 908 // Block the thread 909 SafepointSynchronize::block(thread()); 910 911 // restore oop result, if any 912 if (return_oop) { 913 caller_fr.set_saved_oop_result(&map, return_value()); 914 } 915 } 916 917 // This is a safepoint poll. Verify the return address and block. 918 else { 919 set_at_poll_safepoint(true); 920 921 // verify the blob built the "return address" correctly 922 assert(real_return_addr == caller_fr.pc(), "must match"); 923 924 // Block the thread 925 SafepointSynchronize::block(thread()); 926 set_at_poll_safepoint(false); 927 928 // If we have a pending async exception deoptimize the frame 929 // as otherwise we may never deliver it. 930 if (thread()->has_async_condition()) { 931 ThreadInVMfromJavaNoAsyncException __tiv(thread()); 932 VM_DeoptimizeFrame deopt(thread(), caller_fr.id()); 933 VMThread::execute(&deopt); 934 } 935 936 // If an exception has been installed we must check for a pending deoptimization 937 // Deoptimize frame if exception has been thrown. 938 939 if (thread()->has_pending_exception() ) { 940 RegisterMap map(thread(), true); 941 frame caller_fr = stub_fr.sender(&map); 942 if (caller_fr.is_deoptimized_frame()) { 943 // The exception patch will destroy registers that are still 944 // live and will be needed during deoptimization. Defer the 945 // Async exception should have defered the exception until the 946 // next safepoint which will be detected when we get into 947 // the interpreter so if we have an exception now things 948 // are messed up. 949 950 fatal("Exception installed and deoptimization is pending"); 951 } 952 } 953 } 954} 955 956 957// 958// Statistics & Instrumentations 959// 960SafepointSynchronize::SafepointStats* SafepointSynchronize::_safepoint_stats = NULL; 961int SafepointSynchronize::_cur_stat_index = 0; 962julong SafepointSynchronize::_safepoint_reasons[VM_Operation::VMOp_Terminating]; 963julong SafepointSynchronize::_coalesced_vmop_count = 0; 964jlong SafepointSynchronize::_max_sync_time = 0; 965 966// last_safepoint_start_time records the start time of last safepoint. 967static jlong last_safepoint_start_time = 0; 968static jlong sync_end_time = 0; 969static bool need_to_track_page_armed_status = false; 970static bool init_done = false; 971 972void SafepointSynchronize::deferred_initialize_stat() { 973 if (init_done) return; 974 975 if (PrintSafepointStatisticsCount <= 0) { 976 fatal("Wrong PrintSafepointStatisticsCount"); 977 } 978 979 // If PrintSafepointStatisticsTimeout is specified, the statistics data will 980 // be printed right away, in which case, _safepoint_stats will regress to 981 // a single element array. Otherwise, it is a circular ring buffer with default 982 // size of PrintSafepointStatisticsCount. 983 int stats_array_size; 984 if (PrintSafepointStatisticsTimeout > 0) { 985 stats_array_size = 1; 986 PrintSafepointStatistics = true; 987 } else { 988 stats_array_size = PrintSafepointStatisticsCount; 989 } 990 _safepoint_stats = (SafepointStats*)os::malloc(stats_array_size 991 * sizeof(SafepointStats)); 992 guarantee(_safepoint_stats != NULL, 993 "not enough memory for safepoint instrumentation data"); 994 995 if (UseCompilerSafepoints && DeferPollingPageLoopCount >= 0) { 996 need_to_track_page_armed_status = true; 997 } 998 999 tty->print(" vmop_name " 1000 "[threads: total initially_running wait_to_block] "); 1001 tty->print("[time: spin block sync] " 1002 "[vmop_time time_elapsed] "); 1003 1004 // no page armed status printed out if it is always armed. 1005 if (need_to_track_page_armed_status) { 1006 tty->print("page_armed "); 1007 } 1008 1009 tty->print_cr("page_trap_count"); 1010 1011 init_done = true; 1012} 1013 1014void SafepointSynchronize::begin_statistics(int nof_threads, int nof_running) { 1015 deferred_initialize_stat(); 1016 1017 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; 1018 1019 VM_Operation *op = VMThread::vm_operation(); 1020 spstat->_vmop_type = (op != NULL ? op->type() : -1); 1021 if (op != NULL) { 1022 _safepoint_reasons[spstat->_vmop_type]++; 1023 } 1024 1025 spstat->_nof_total_threads = nof_threads; 1026 spstat->_nof_initial_running_threads = nof_running; 1027 spstat->_nof_threads_hit_page_trap = 0; 1028 1029 // Records the start time of spinning. The real time spent on spinning 1030 // will be adjusted when spin is done. Same trick is applied for time 1031 // spent on waiting for threads to block. 1032 if (nof_running != 0) { 1033 spstat->_time_to_spin = os::javaTimeNanos(); 1034 } else { 1035 spstat->_time_to_spin = 0; 1036 } 1037 1038 if (last_safepoint_start_time == 0) { 1039 spstat->_time_elapsed_since_last_safepoint = 0; 1040 } else { 1041 spstat->_time_elapsed_since_last_safepoint = _last_safepoint - 1042 last_safepoint_start_time; 1043 } 1044 last_safepoint_start_time = _last_safepoint; 1045} 1046 1047void SafepointSynchronize::update_statistics_on_spin_end() { 1048 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; 1049 1050 jlong cur_time = os::javaTimeNanos(); 1051 1052 spstat->_nof_threads_wait_to_block = _waiting_to_block; 1053 if (spstat->_nof_initial_running_threads != 0) { 1054 spstat->_time_to_spin = cur_time - spstat->_time_to_spin; 1055 } 1056 1057 if (need_to_track_page_armed_status) { 1058 spstat->_page_armed = (PageArmed == 1); 1059 } 1060 1061 // Records the start time of waiting for to block. Updated when block is done. 1062 if (_waiting_to_block != 0) { 1063 spstat->_time_to_wait_to_block = cur_time; 1064 } else { 1065 spstat->_time_to_wait_to_block = 0; 1066 } 1067} 1068 1069void SafepointSynchronize::update_statistics_on_sync_end(jlong end_time) { 1070 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; 1071 1072 if (spstat->_nof_threads_wait_to_block != 0) { 1073 spstat->_time_to_wait_to_block = end_time - 1074 spstat->_time_to_wait_to_block; 1075 } 1076 1077 // Records the end time of sync which will be used to calculate the total 1078 // vm operation time. Again, the real time spending in syncing will be deducted 1079 // from the start of the sync time later when end_statistics is called. 1080 spstat->_time_to_sync = end_time - _last_safepoint; 1081 if (spstat->_time_to_sync > _max_sync_time) { 1082 _max_sync_time = spstat->_time_to_sync; 1083 } 1084 sync_end_time = end_time; 1085} 1086 1087void SafepointSynchronize::end_statistics(jlong vmop_end_time) { 1088 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; 1089 1090 // Update the vm operation time. 1091 spstat->_time_to_exec_vmop = vmop_end_time - sync_end_time; 1092 // Only the sync time longer than the specified 1093 // PrintSafepointStatisticsTimeout will be printed out right away. 1094 // By default, it is -1 meaning all samples will be put into the list. 1095 if ( PrintSafepointStatisticsTimeout > 0) { 1096 if (spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) { 1097 print_statistics(); 1098 } 1099 } else { 1100 // The safepoint statistics will be printed out when the _safepoin_stats 1101 // array fills up. 1102 if (_cur_stat_index != PrintSafepointStatisticsCount - 1) { 1103 _cur_stat_index ++; 1104 } else { 1105 print_statistics(); 1106 _cur_stat_index = 0; 1107 tty->print_cr(""); 1108 } 1109 } 1110} 1111 1112void SafepointSynchronize::print_statistics() { 1113 int index; 1114 SafepointStats* sstats = _safepoint_stats; 1115 1116 for (index = 0; index <= _cur_stat_index; index++) { 1117 sstats = &_safepoint_stats[index]; 1118 tty->print("%-28s [" 1119 INT32_FORMAT_W(8)INT32_FORMAT_W(11)INT32_FORMAT_W(15) 1120 "] ", 1121 sstats->_vmop_type == -1 ? "no vm operation" : 1122 VM_Operation::name(sstats->_vmop_type), 1123 sstats->_nof_total_threads, 1124 sstats->_nof_initial_running_threads, 1125 sstats->_nof_threads_wait_to_block); 1126 // "/ MICROUNITS " is to convert the unit from nanos to millis. 1127 tty->print(" [" 1128 INT64_FORMAT_W(6)INT64_FORMAT_W(6)INT64_FORMAT_W(6) 1129 "] " 1130 "["INT64_FORMAT_W(6)INT64_FORMAT_W(9) "] ", 1131 sstats->_time_to_spin / MICROUNITS, 1132 sstats->_time_to_wait_to_block / MICROUNITS, 1133 sstats->_time_to_sync / MICROUNITS, 1134 sstats->_time_to_exec_vmop / MICROUNITS, 1135 sstats->_time_elapsed_since_last_safepoint / MICROUNITS); 1136 1137 if (need_to_track_page_armed_status) { 1138 tty->print(INT32_FORMAT" ", sstats->_page_armed); 1139 } 1140 tty->print_cr(INT32_FORMAT" ", sstats->_nof_threads_hit_page_trap); 1141 } 1142} 1143 1144// This method will be called when VM exits. It will first call 1145// print_statistics to print out the rest of the sampling. Then 1146// it tries to summarize the sampling. 1147void SafepointSynchronize::print_stat_on_exit() { 1148 if (_safepoint_stats == NULL) return; 1149 1150 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; 1151 1152 // During VM exit, end_statistics may not get called and in that 1153 // case, if the sync time is less than PrintSafepointStatisticsTimeout, 1154 // don't print it out. 1155 // Approximate the vm op time. 1156 _safepoint_stats[_cur_stat_index]._time_to_exec_vmop = 1157 os::javaTimeNanos() - sync_end_time; 1158 1159 if ( PrintSafepointStatisticsTimeout < 0 || 1160 spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) { 1161 print_statistics(); 1162 } 1163 tty->print_cr(""); 1164 1165 // Print out polling page sampling status. 1166 if (!need_to_track_page_armed_status) { 1167 if (UseCompilerSafepoints) { 1168 tty->print_cr("Polling page always armed"); 1169 } 1170 } else { 1171 tty->print_cr("Defer polling page loop count = %d\n", 1172 DeferPollingPageLoopCount); 1173 } 1174 1175 for (int index = 0; index < VM_Operation::VMOp_Terminating; index++) { 1176 if (_safepoint_reasons[index] != 0) { 1177 tty->print_cr("%-26s"UINT64_FORMAT_W(10), VM_Operation::name(index), 1178 _safepoint_reasons[index]); 1179 } 1180 } 1181 1182 tty->print_cr(UINT64_FORMAT_W(5)" VM operations coalesced during safepoint", 1183 _coalesced_vmop_count); 1184 tty->print_cr("Maximum sync time "INT64_FORMAT_W(5)" ms", 1185 _max_sync_time / MICROUNITS); 1186} 1187 1188// ------------------------------------------------------------------------------------------------ 1189// Non-product code 1190 1191#ifndef PRODUCT 1192 1193void SafepointSynchronize::print_state() { 1194 if (_state == _not_synchronized) { 1195 tty->print_cr("not synchronized"); 1196 } else if (_state == _synchronizing || _state == _synchronized) { 1197 tty->print_cr("State: %s", (_state == _synchronizing) ? "synchronizing" : 1198 "synchronized"); 1199 1200 for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) { 1201 cur->safepoint_state()->print(); 1202 } 1203 } 1204} 1205 1206void SafepointSynchronize::safepoint_msg(const char* format, ...) { 1207 if (ShowSafepointMsgs) { 1208 va_list ap; 1209 va_start(ap, format); 1210 tty->vprint_cr(format, ap); 1211 va_end(ap); 1212 } 1213} 1214 1215#endif // !PRODUCT 1216