annotate hotspot/src/share/vm/runtime/safepoint.cpp @ 22551:9bf46d16dcc6

8025856: Fix typos in the GC code Summary: Fix about 440 typos in comments in the VM code Reviewed-by: mgerdin, tschatzl, coleenp, kmo, jcoomes
author jwilhelm
date Thu, 23 Jan 2014 14:47:23 +0100
parents fe4818444117
children 27c4307d6cda
rev   line source
duke@1 1 /*
hseigel@20282 2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
duke@1 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1 4 *
duke@1 5 * This code is free software; you can redistribute it and/or modify it
duke@1 6 * under the terms of the GNU General Public License version 2 only, as
duke@1 7 * published by the Free Software Foundation.
duke@1 8 *
duke@1 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@1 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@1 13 * accompanied this code).
duke@1 14 *
duke@1 15 * You should have received a copy of the GNU General Public License version
duke@1 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@1 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1 18 *
trims@5547 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@5547 20 * or visit www.oracle.com if you need additional information or have any
trims@5547 21 * questions.
duke@1 22 *
duke@1 23 */
duke@1 24
stefank@7397 25 #include "precompiled.hpp"
coleenp@13087 26 #include "classfile/symbolTable.hpp"
stefank@7397 27 #include "classfile/systemDictionary.hpp"
stefank@7397 28 #include "code/codeCache.hpp"
stefank@7397 29 #include "code/icBuffer.hpp"
stefank@7397 30 #include "code/nmethod.hpp"
stefank@7397 31 #include "code/pcDesc.hpp"
stefank@7397 32 #include "code/scopeDesc.hpp"
stefank@7397 33 #include "gc_interface/collectedHeap.hpp"
stefank@7397 34 #include "interpreter/interpreter.hpp"
stefank@7397 35 #include "memory/resourceArea.hpp"
stefank@7397 36 #include "memory/universe.inline.hpp"
stefank@7397 37 #include "oops/oop.inline.hpp"
coleenp@8076 38 #include "oops/symbol.hpp"
stefank@7397 39 #include "runtime/compilationPolicy.hpp"
stefank@7397 40 #include "runtime/deoptimization.hpp"
stefank@7397 41 #include "runtime/frame.inline.hpp"
stefank@7397 42 #include "runtime/interfaceSupport.hpp"
stefank@7397 43 #include "runtime/mutexLocker.hpp"
stefank@7397 44 #include "runtime/osThread.hpp"
stefank@7397 45 #include "runtime/safepoint.hpp"
stefank@7397 46 #include "runtime/signature.hpp"
stefank@7397 47 #include "runtime/stubCodeGenerator.hpp"
stefank@7397 48 #include "runtime/stubRoutines.hpp"
stefank@7397 49 #include "runtime/sweeper.hpp"
stefank@7397 50 #include "runtime/synchronizer.hpp"
stefank@14583 51 #include "runtime/thread.inline.hpp"
zgu@13195 52 #include "services/memTracker.hpp"
stefank@7397 53 #include "services/runtimeService.hpp"
stefank@7397 54 #include "utilities/events.hpp"
jprovino@15482 55 #include "utilities/macros.hpp"
stefank@7397 56 #ifdef TARGET_ARCH_x86
stefank@7397 57 # include "nativeInst_x86.hpp"
stefank@7397 58 # include "vmreg_x86.inline.hpp"
stefank@7397 59 #endif
stefank@7397 60 #ifdef TARGET_ARCH_sparc
stefank@7397 61 # include "nativeInst_sparc.hpp"
stefank@7397 62 # include "vmreg_sparc.inline.hpp"
stefank@7397 63 #endif
stefank@7397 64 #ifdef TARGET_ARCH_zero
stefank@7397 65 # include "nativeInst_zero.hpp"
stefank@7397 66 # include "vmreg_zero.inline.hpp"
stefank@7397 67 #endif
bobv@8107 68 #ifdef TARGET_ARCH_arm
bobv@8107 69 # include "nativeInst_arm.hpp"
bobv@8107 70 # include "vmreg_arm.inline.hpp"
bobv@8107 71 #endif
bobv@8107 72 #ifdef TARGET_ARCH_ppc
bobv@8107 73 # include "nativeInst_ppc.hpp"
bobv@8107 74 # include "vmreg_ppc.inline.hpp"
bobv@8107 75 #endif
jprovino@15482 76 #if INCLUDE_ALL_GCS
stefank@7397 77 #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
stefank@7397 78 #include "gc_implementation/shared/concurrentGCThread.hpp"
jprovino@15482 79 #endif // INCLUDE_ALL_GCS
stefank@7397 80 #ifdef COMPILER1
stefank@7397 81 #include "c1/c1_globals.hpp"
stefank@7397 82 #endif
duke@1 83
duke@1 84 // --------------------------------------------------------------------------------------------------
duke@1 85 // Implementation of Safepoint begin/end
duke@1 86
duke@1 87 SafepointSynchronize::SynchronizeState volatile SafepointSynchronize::_state = SafepointSynchronize::_not_synchronized;
duke@1 88 volatile int SafepointSynchronize::_waiting_to_block = 0;
duke@1 89 volatile int SafepointSynchronize::_safepoint_counter = 0;
never@11631 90 int SafepointSynchronize::_current_jni_active_count = 0;
xlu@5042 91 long SafepointSynchronize::_end_of_last_safepoint = 0;
duke@1 92 static volatile int PageArmed = 0 ; // safepoint polling page is RO|RW vs PROT_NONE
duke@1 93 static volatile int TryingToBlock = 0 ; // proximate value -- for advisory use only
duke@1 94 static bool timeout_error_printed = false;
duke@1 95
duke@1 96 // Roll all threads forward to a safepoint and suspend them all
duke@1 97 void SafepointSynchronize::begin() {
duke@1 98
duke@1 99 Thread* myThread = Thread::current();
duke@1 100 assert(myThread->is_VM_thread(), "Only VM thread may execute a safepoint");
duke@1 101
xlu@5042 102 if (PrintSafepointStatistics || PrintSafepointStatisticsTimeout > 0) {
xlu@5042 103 _safepoint_begin_time = os::javaTimeNanos();
xlu@5042 104 _ts_of_current_safepoint = tty->time_stamp().seconds();
xlu@5042 105 }
duke@1 106
jprovino@15482 107 #if INCLUDE_ALL_GCS
duke@1 108 if (UseConcMarkSweepGC) {
duke@1 109 // In the future we should investigate whether CMS can use the
duke@1 110 // more-general mechanism below. DLD (01/05).
duke@1 111 ConcurrentMarkSweepThread::synchronize(false);
ysr@3262 112 } else if (UseG1GC) {
duke@1 113 ConcurrentGCThread::safepoint_synchronize();
duke@1 114 }
jprovino@15482 115 #endif // INCLUDE_ALL_GCS
duke@1 116
duke@1 117 // By getting the Threads_lock, we assure that no threads are about to start or
duke@1 118 // exit. It is released again in SafepointSynchronize::end().
duke@1 119 Threads_lock->lock();
duke@1 120
duke@1 121 assert( _state == _not_synchronized, "trying to safepoint synchronize with wrong state");
duke@1 122
duke@1 123 int nof_threads = Threads::number_of_threads();
duke@1 124
duke@1 125 if (TraceSafepoint) {
duke@1 126 tty->print_cr("Safepoint synchronization initiated. (%d)", nof_threads);
duke@1 127 }
duke@1 128
duke@1 129 RuntimeService::record_safepoint_begin();
duke@1 130
duke@1 131 MutexLocker mu(Safepoint_lock);
duke@1 132
never@11631 133 // Reset the count of active JNI critical threads
never@11631 134 _current_jni_active_count = 0;
never@11631 135
duke@1 136 // Set number of threads to wait for, before we initiate the callbacks
duke@1 137 _waiting_to_block = nof_threads;
duke@1 138 TryingToBlock = 0 ;
duke@1 139 int still_running = nof_threads;
duke@1 140
duke@1 141 // Save the starting time, so that it can be compared to see if this has taken
duke@1 142 // too long to complete.
duke@1 143 jlong safepoint_limit_time;
duke@1 144 timeout_error_printed = false;
duke@1 145
xlu@4006 146 // PrintSafepointStatisticsTimeout can be specified separately. When
xlu@4006 147 // specified, PrintSafepointStatistics will be set to true in
xlu@4006 148 // deferred_initialize_stat method. The initialization has to be done
xlu@4006 149 // early enough to avoid any races. See bug 6880029 for details.
xlu@4006 150 if (PrintSafepointStatistics || PrintSafepointStatisticsTimeout > 0) {
xlu@4006 151 deferred_initialize_stat();
xlu@4006 152 }
xlu@4006 153
duke@1 154 // Begin the process of bringing the system to a safepoint.
duke@1 155 // Java threads can be in several different states and are
duke@1 156 // stopped by different mechanisms:
duke@1 157 //
duke@1 158 // 1. Running interpreted
jwilhelm@22551 159 // The interpreter dispatch table is changed to force it to
duke@1 160 // check for a safepoint condition between bytecodes.
duke@1 161 // 2. Running in native code
duke@1 162 // When returning from the native code, a Java thread must check
duke@1 163 // the safepoint _state to see if we must block. If the
duke@1 164 // VM thread sees a Java thread in native, it does
duke@1 165 // not wait for this thread to block. The order of the memory
duke@1 166 // writes and reads of both the safepoint state and the Java
duke@1 167 // threads state is critical. In order to guarantee that the
duke@1 168 // memory writes are serialized with respect to each other,
duke@1 169 // the VM thread issues a memory barrier instruction
duke@1 170 // (on MP systems). In order to avoid the overhead of issuing
duke@1 171 // a memory barrier for each Java thread making native calls, each Java
duke@1 172 // thread performs a write to a single memory page after changing
duke@1 173 // the thread state. The VM thread performs a sequence of
duke@1 174 // mprotect OS calls which forces all previous writes from all
duke@1 175 // Java threads to be serialized. This is done in the
duke@1 176 // os::serialize_thread_states() call. This has proven to be
duke@1 177 // much more efficient than executing a membar instruction
duke@1 178 // on every call to native code.
duke@1 179 // 3. Running compiled Code
duke@1 180 // Compiled code reads a global (Safepoint Polling) page that
duke@1 181 // is set to fault if we are trying to get to a safepoint.
duke@1 182 // 4. Blocked
duke@1 183 // A thread which is blocked will not be allowed to return from the
duke@1 184 // block condition until the safepoint operation is complete.
duke@1 185 // 5. In VM or Transitioning between states
duke@1 186 // If a Java thread is currently running in the VM or transitioning
duke@1 187 // between states, the safepointing code will wait for the thread to
duke@1 188 // block itself when it attempts transitions to a new state.
duke@1 189 //
duke@1 190 _state = _synchronizing;
duke@1 191 OrderAccess::fence();
duke@1 192
duke@1 193 // Flush all thread states to memory
duke@1 194 if (!UseMembar) {
duke@1 195 os::serialize_thread_states();
duke@1 196 }
duke@1 197
duke@1 198 // Make interpreter safepoint aware
duke@1 199 Interpreter::notice_safepoints();
duke@1 200
duke@1 201 if (UseCompilerSafepoints && DeferPollingPageLoopCount < 0) {
duke@1 202 // Make polling safepoint aware
duke@1 203 guarantee (PageArmed == 0, "invariant") ;
duke@1 204 PageArmed = 1 ;
duke@1 205 os::make_polling_page_unreadable();
duke@1 206 }
duke@1 207
duke@1 208 // Consider using active_processor_count() ... but that call is expensive.
duke@1 209 int ncpus = os::processor_count() ;
duke@1 210
duke@1 211 #ifdef ASSERT
duke@1 212 for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {
duke@1 213 assert(cur->safepoint_state()->is_running(), "Illegal initial state");
never@12108 214 // Clear the visited flag to ensure that the critical counts are collected properly.
never@12108 215 cur->set_visited_for_critical_count(false);
duke@1 216 }
duke@1 217 #endif // ASSERT
duke@1 218
duke@1 219 if (SafepointTimeout)
duke@1 220 safepoint_limit_time = os::javaTimeNanos() + (jlong)SafepointTimeoutDelay * MICROUNITS;
duke@1 221
duke@1 222 // Iterate through all threads until it have been determined how to stop them all at a safepoint
duke@1 223 unsigned int iterations = 0;
duke@1 224 int steps = 0 ;
duke@1 225 while(still_running > 0) {
duke@1 226 for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {
duke@1 227 assert(!cur->is_ConcurrentGC_thread(), "A concurrent GC thread is unexpectly being suspended");
duke@1 228 ThreadSafepointState *cur_state = cur->safepoint_state();
duke@1 229 if (cur_state->is_running()) {
duke@1 230 cur_state->examine_state_of_thread();
duke@1 231 if (!cur_state->is_running()) {
duke@1 232 still_running--;
duke@1 233 // consider adjusting steps downward:
duke@1 234 // steps = 0
duke@1 235 // steps -= NNN
duke@1 236 // steps >>= 1
duke@1 237 // steps = MIN(steps, 2000-100)
duke@1 238 // if (iterations != 0) steps -= NNN
duke@1 239 }
duke@1 240 if (TraceSafepoint && Verbose) cur_state->print();
duke@1 241 }
duke@1 242 }
duke@1 243
xlu@4006 244 if (PrintSafepointStatistics && iterations == 0) {
duke@1 245 begin_statistics(nof_threads, still_running);
duke@1 246 }
duke@1 247
duke@1 248 if (still_running > 0) {
duke@1 249 // Check for if it takes to long
duke@1 250 if (SafepointTimeout && safepoint_limit_time < os::javaTimeNanos()) {
duke@1 251 print_safepoint_timeout(_spinning_timeout);
duke@1 252 }
duke@1 253
duke@1 254 // Spin to avoid context switching.
duke@1 255 // There's a tension between allowing the mutators to run (and rendezvous)
duke@1 256 // vs spinning. As the VM thread spins, wasting cycles, it consumes CPU that
duke@1 257 // a mutator might otherwise use profitably to reach a safepoint. Excessive
duke@1 258 // spinning by the VM thread on a saturated system can increase rendezvous latency.
duke@1 259 // Blocking or yielding incur their own penalties in the form of context switching
duke@1 260 // and the resultant loss of $ residency.
duke@1 261 //
duke@1 262 // Further complicating matters is that yield() does not work as naively expected
duke@1 263 // on many platforms -- yield() does not guarantee that any other ready threads
duke@1 264 // will run. As such we revert yield_all() after some number of iterations.
duke@1 265 // Yield_all() is implemented as a short unconditional sleep on some platforms.
duke@1 266 // Typical operating systems round a "short" sleep period up to 10 msecs, so sleeping
duke@1 267 // can actually increase the time it takes the VM thread to detect that a system-wide
duke@1 268 // stop-the-world safepoint has been reached. In a pathological scenario such as that
duke@1 269 // described in CR6415670 the VMthread may sleep just before the mutator(s) become safe.
duke@1 270 // In that case the mutators will be stalled waiting for the safepoint to complete and the
duke@1 271 // the VMthread will be sleeping, waiting for the mutators to rendezvous. The VMthread
duke@1 272 // will eventually wake up and detect that all mutators are safe, at which point
duke@1 273 // we'll again make progress.
duke@1 274 //
duke@1 275 // Beware too that that the VMThread typically runs at elevated priority.
duke@1 276 // Its default priority is higher than the default mutator priority.
duke@1 277 // Obviously, this complicates spinning.
duke@1 278 //
duke@1 279 // Note too that on Windows XP SwitchThreadTo() has quite different behavior than Sleep(0).
duke@1 280 // Sleep(0) will _not yield to lower priority threads, while SwitchThreadTo() will.
duke@1 281 //
duke@1 282 // See the comments in synchronizer.cpp for additional remarks on spinning.
duke@1 283 //
duke@1 284 // In the future we might:
jwilhelm@22551 285 // 1. Modify the safepoint scheme to avoid potentially unbounded spinning.
duke@1 286 // This is tricky as the path used by a thread exiting the JVM (say on
duke@1 287 // on JNI call-out) simply stores into its state field. The burden
duke@1 288 // is placed on the VM thread, which must poll (spin).
duke@1 289 // 2. Find something useful to do while spinning. If the safepoint is GC-related
duke@1 290 // we might aggressively scan the stacks of threads that are already safe.
duke@1 291 // 3. Use Solaris schedctl to examine the state of the still-running mutators.
duke@1 292 // If all the mutators are ONPROC there's no reason to sleep or yield.
duke@1 293 // 4. YieldTo() any still-running mutators that are ready but OFFPROC.
duke@1 294 // 5. Check system saturation. If the system is not fully saturated then
duke@1 295 // simply spin and avoid sleep/yield.
duke@1 296 // 6. As still-running mutators rendezvous they could unpark the sleeping
duke@1 297 // VMthread. This works well for still-running mutators that become
duke@1 298 // safe. The VMthread must still poll for mutators that call-out.
duke@1 299 // 7. Drive the policy on time-since-begin instead of iterations.
duke@1 300 // 8. Consider making the spin duration a function of the # of CPUs:
duke@1 301 // Spin = (((ncpus-1) * M) + K) + F(still_running)
duke@1 302 // Alternately, instead of counting iterations of the outer loop
duke@1 303 // we could count the # of threads visited in the inner loop, above.
duke@1 304 // 9. On windows consider using the return value from SwitchThreadTo()
duke@1 305 // to drive subsequent spin/SwitchThreadTo()/Sleep(N) decisions.
duke@1 306
duke@1 307 if (UseCompilerSafepoints && int(iterations) == DeferPollingPageLoopCount) {
duke@1 308 guarantee (PageArmed == 0, "invariant") ;
duke@1 309 PageArmed = 1 ;
duke@1 310 os::make_polling_page_unreadable();
duke@1 311 }
duke@1 312
duke@1 313 // Instead of (ncpus > 1) consider either (still_running < (ncpus + EPSILON)) or
duke@1 314 // ((still_running + _waiting_to_block - TryingToBlock)) < ncpus)
duke@1 315 ++steps ;
duke@1 316 if (ncpus > 1 && steps < SafepointSpinBeforeYield) {
duke@1 317 SpinPause() ; // MP-Polite spin
duke@1 318 } else
duke@1 319 if (steps < DeferThrSuspendLoopCount) {
duke@1 320 os::NakedYield() ;
duke@1 321 } else {
duke@1 322 os::yield_all(steps) ;
duke@1 323 // Alternately, the VM thread could transiently depress its scheduling priority or
duke@1 324 // transiently increase the priority of the tardy mutator(s).
duke@1 325 }
duke@1 326
duke@1 327 iterations ++ ;
duke@1 328 }
duke@1 329 assert(iterations < (uint)max_jint, "We have been iterating in the safepoint loop too long");
duke@1 330 }
duke@1 331 assert(still_running == 0, "sanity check");
duke@1 332
duke@1 333 if (PrintSafepointStatistics) {
duke@1 334 update_statistics_on_spin_end();
duke@1 335 }
duke@1 336
duke@1 337 // wait until all threads are stopped
duke@1 338 while (_waiting_to_block > 0) {
duke@1 339 if (TraceSafepoint) tty->print_cr("Waiting for %d thread(s) to block", _waiting_to_block);
duke@1 340 if (!SafepointTimeout || timeout_error_printed) {
duke@1 341 Safepoint_lock->wait(true); // true, means with no safepoint checks
duke@1 342 } else {
duke@1 343 // Compute remaining time
duke@1 344 jlong remaining_time = safepoint_limit_time - os::javaTimeNanos();
duke@1 345
duke@1 346 // If there is no remaining time, then there is an error
duke@1 347 if (remaining_time < 0 || Safepoint_lock->wait(true, remaining_time / MICROUNITS)) {
duke@1 348 print_safepoint_timeout(_blocking_timeout);
duke@1 349 }
duke@1 350 }
duke@1 351 }
duke@1 352 assert(_waiting_to_block == 0, "sanity check");
duke@1 353
duke@1 354 #ifndef PRODUCT
duke@1 355 if (SafepointTimeout) {
duke@1 356 jlong current_time = os::javaTimeNanos();
duke@1 357 if (safepoint_limit_time < current_time) {
duke@1 358 tty->print_cr("# SafepointSynchronize: Finished after "
duke@1 359 INT64_FORMAT_W(6) " ms",
duke@1 360 ((current_time - safepoint_limit_time) / MICROUNITS +
duke@1 361 SafepointTimeoutDelay));
duke@1 362 }
duke@1 363 }
duke@1 364 #endif
duke@1 365
duke@1 366 assert((_safepoint_counter & 0x1) == 0, "must be even");
duke@1 367 assert(Threads_lock->owned_by_self(), "must hold Threads_lock");
duke@1 368 _safepoint_counter ++;
duke@1 369
duke@1 370 // Record state
duke@1 371 _state = _synchronized;
duke@1 372
duke@1 373 OrderAccess::fence();
duke@1 374
never@12108 375 #ifdef ASSERT
never@12108 376 for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {
never@12108 377 // make sure all the threads were visited
never@12108 378 assert(cur->was_visited_for_critical_count(), "missed a thread");
never@12108 379 }
never@12108 380 #endif // ASSERT
never@12108 381
never@11631 382 // Update the count of active JNI critical regions
never@11631 383 GC_locker::set_jni_lock_count(_current_jni_active_count);
never@11631 384
duke@1 385 if (TraceSafepoint) {
duke@1 386 VM_Operation *op = VMThread::vm_operation();
duke@1 387 tty->print_cr("Entering safepoint region: %s", (op != NULL) ? op->name() : "no vm operation");
duke@1 388 }
duke@1 389
duke@1 390 RuntimeService::record_safepoint_synchronized();
duke@1 391 if (PrintSafepointStatistics) {
duke@1 392 update_statistics_on_sync_end(os::javaTimeNanos());
duke@1 393 }
duke@1 394
duke@1 395 // Call stuff that needs to be run when a safepoint is just about to be completed
duke@1 396 do_cleanup_tasks();
xlu@5042 397
xlu@5042 398 if (PrintSafepointStatistics) {
xlu@5042 399 // Record how much time spend on the above cleanup tasks
xlu@5042 400 update_statistics_on_cleanup_end(os::javaTimeNanos());
xlu@5042 401 }
duke@1 402 }
duke@1 403
duke@1 404 // Wake up all threads, so they are ready to resume execution after the safepoint
duke@1 405 // operation has been carried out
duke@1 406 void SafepointSynchronize::end() {
duke@1 407
duke@1 408 assert(Threads_lock->owned_by_self(), "must hold Threads_lock");
duke@1 409 assert((_safepoint_counter & 0x1) == 1, "must be odd");
duke@1 410 _safepoint_counter ++;
duke@1 411 // memory fence isn't required here since an odd _safepoint_counter
duke@1 412 // value can do no harm and a fence is issued below anyway.
duke@1 413
duke@1 414 DEBUG_ONLY(Thread* myThread = Thread::current();)
duke@1 415 assert(myThread->is_VM_thread(), "Only VM thread can execute a safepoint");
duke@1 416
duke@1 417 if (PrintSafepointStatistics) {
duke@1 418 end_statistics(os::javaTimeNanos());
duke@1 419 }
duke@1 420
duke@1 421 #ifdef ASSERT
duke@1 422 // A pending_exception cannot be installed during a safepoint. The threads
duke@1 423 // may install an async exception after they come back from a safepoint into
duke@1 424 // pending_exception after they unblock. But that should happen later.
duke@1 425 for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) {
duke@1 426 assert (!(cur->has_pending_exception() &&
duke@1 427 cur->safepoint_state()->is_at_poll_safepoint()),
duke@1 428 "safepoint installed a pending exception");
duke@1 429 }
duke@1 430 #endif // ASSERT
duke@1 431
duke@1 432 if (PageArmed) {
duke@1 433 // Make polling safepoint aware
duke@1 434 os::make_polling_page_readable();
duke@1 435 PageArmed = 0 ;
duke@1 436 }
duke@1 437
duke@1 438 // Remove safepoint check from interpreter
duke@1 439 Interpreter::ignore_safepoints();
duke@1 440
duke@1 441 {
duke@1 442 MutexLocker mu(Safepoint_lock);
duke@1 443
duke@1 444 assert(_state == _synchronized, "must be synchronized before ending safepoint synchronization");
duke@1 445
duke@1 446 // Set to not synchronized, so the threads will not go into the signal_thread_blocked method
duke@1 447 // when they get restarted.
duke@1 448 _state = _not_synchronized;
duke@1 449 OrderAccess::fence();
duke@1 450
duke@1 451 if (TraceSafepoint) {
duke@1 452 tty->print_cr("Leaving safepoint region");
duke@1 453 }
duke@1 454
duke@1 455 // Start suspended threads
duke@1 456 for(JavaThread *current = Threads::first(); current; current = current->next()) {
twisti@2131 457 // A problem occurring on Solaris is when attempting to restart threads
duke@1 458 // the first #cpus - 1 go well, but then the VMThread is preempted when we get
duke@1 459 // to the next one (since it has been running the longest). We then have
duke@1 460 // to wait for a cpu to become available before we can continue restarting
duke@1 461 // threads.
duke@1 462 // FIXME: This causes the performance of the VM to degrade when active and with
duke@1 463 // large numbers of threads. Apparently this is due to the synchronous nature
duke@1 464 // of suspending threads.
duke@1 465 //
duke@1 466 // TODO-FIXME: the comments above are vestigial and no longer apply.
duke@1 467 // Furthermore, using solaris' schedctl in this particular context confers no benefit
duke@1 468 if (VMThreadHintNoPreempt) {
duke@1 469 os::hint_no_preempt();
duke@1 470 }
duke@1 471 ThreadSafepointState* cur_state = current->safepoint_state();
duke@1 472 assert(cur_state->type() != ThreadSafepointState::_running, "Thread not suspended at safepoint");
duke@1 473 cur_state->restart();
duke@1 474 assert(cur_state->is_running(), "safepoint state has not been reset");
duke@1 475 }
duke@1 476
duke@1 477 RuntimeService::record_safepoint_end();
duke@1 478
duke@1 479 // Release threads lock, so threads can be created/destroyed again. It will also starts all threads
duke@1 480 // blocked in signal_thread_blocked
duke@1 481 Threads_lock->unlock();
duke@1 482
duke@1 483 }
jprovino@15482 484 #if INCLUDE_ALL_GCS
duke@1 485 // If there are any concurrent GC threads resume them.
duke@1 486 if (UseConcMarkSweepGC) {
duke@1 487 ConcurrentMarkSweepThread::desynchronize(false);
ysr@3262 488 } else if (UseG1GC) {
duke@1 489 ConcurrentGCThread::safepoint_desynchronize();
duke@1 490 }
jprovino@15482 491 #endif // INCLUDE_ALL_GCS
jwilhelm@22551 492 // record this time so VMThread can keep track how much time has elapsed
xlu@5042 493 // since last safepoint.
xlu@5042 494 _end_of_last_safepoint = os::javaTimeMillis();
duke@1 495 }
duke@1 496
duke@1 497 bool SafepointSynchronize::is_cleanup_needed() {
duke@1 498 // Need a safepoint if some inline cache buffers is non-empty
duke@1 499 if (!InlineCacheBuffer::is_empty()) return true;
duke@1 500 return false;
duke@1 501 }
duke@1 502
duke@1 503
duke@1 504
duke@1 505 // Various cleaning tasks that should be done periodically at safepoints
duke@1 506 void SafepointSynchronize::do_cleanup_tasks() {
xlu@5042 507 {
xlu@5086 508 TraceTime t1("deflating idle monitors", TraceSafepointCleanupTime);
xlu@5042 509 ObjectSynchronizer::deflate_idle_monitors();
duke@1 510 }
duke@1 511
xlu@5042 512 {
xlu@5086 513 TraceTime t2("updating inline caches", TraceSafepointCleanupTime);
xlu@5042 514 InlineCacheBuffer::update_inline_caches();
xlu@5042 515 }
iveresov@6453 516 {
iveresov@6453 517 TraceTime t3("compilation policy safepoint handler", TraceSafepointCleanupTime);
iveresov@6453 518 CompilationPolicy::policy()->do_safepoint_work();
duke@1 519 }
xlu@5042 520
coleenp@13087 521 {
anoll@20290 522 TraceTime t4("mark nmethods", TraceSafepointCleanupTime);
anoll@20290 523 NMethodSweeper::mark_active_nmethods();
coleenp@13087 524 }
coleenp@13087 525
coleenp@13087 526 if (SymbolTable::needs_rehashing()) {
coleenp@13087 527 TraceTime t5("rehashing symbol table", TraceSafepointCleanupTime);
coleenp@13087 528 SymbolTable::rehash_table();
coleenp@13087 529 }
coleenp@13087 530
coleenp@13087 531 if (StringTable::needs_rehashing()) {
coleenp@13087 532 TraceTime t6("rehashing string table", TraceSafepointCleanupTime);
coleenp@13087 533 StringTable::rehash_table();
coleenp@13087 534 }
minqi@9990 535
minqi@9990 536 // rotate log files?
minqi@9990 537 if (UseGCLogFileRotation) {
minqi@9990 538 gclog_or_tty->rotate_log();
minqi@9990 539 }
zgu@13195 540
zgu@13195 541 if (MemTracker::is_on()) {
zgu@13195 542 MemTracker::sync();
zgu@13195 543 }
duke@1 544 }
duke@1 545
duke@1 546
duke@1 547 bool SafepointSynchronize::safepoint_safe(JavaThread *thread, JavaThreadState state) {
duke@1 548 switch(state) {
duke@1 549 case _thread_in_native:
duke@1 550 // native threads are safe if they have no java stack or have walkable stack
duke@1 551 return !thread->has_last_Java_frame() || thread->frame_anchor()->walkable();
duke@1 552
duke@1 553 // blocked threads should have already have walkable stack
duke@1 554 case _thread_blocked:
duke@1 555 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "blocked and not walkable");
duke@1 556 return true;
duke@1 557
duke@1 558 default:
duke@1 559 return false;
duke@1 560 }
duke@1 561 }
duke@1 562
duke@1 563
never@11637 564 // See if the thread is running inside a lazy critical native and
never@11637 565 // update the thread critical count if so. Also set a suspend flag to
never@11637 566 // cause the native wrapper to return into the JVM to do the unlock
never@11637 567 // once the native finishes.
never@11637 568 void SafepointSynchronize::check_for_lazy_critical_native(JavaThread *thread, JavaThreadState state) {
never@11637 569 if (state == _thread_in_native &&
never@11637 570 thread->has_last_Java_frame() &&
never@11637 571 thread->frame_anchor()->walkable()) {
never@11637 572 // This thread might be in a critical native nmethod so look at
never@11637 573 // the top of the stack and increment the critical count if it
never@11637 574 // is.
never@11637 575 frame wrapper_frame = thread->last_frame();
never@11637 576 CodeBlob* stub_cb = wrapper_frame.cb();
never@11637 577 if (stub_cb != NULL &&
never@11637 578 stub_cb->is_nmethod() &&
never@11637 579 stub_cb->as_nmethod_or_null()->is_lazy_critical_native()) {
never@11637 580 // A thread could potentially be in a critical native across
never@11637 581 // more than one safepoint, so only update the critical state on
never@11637 582 // the first one. When it returns it will perform the unlock.
never@11637 583 if (!thread->do_critical_native_unlock()) {
never@11637 584 #ifdef ASSERT
never@11637 585 if (!thread->in_critical()) {
never@11637 586 GC_locker::increment_debug_jni_lock_count();
never@11637 587 }
never@11637 588 #endif
never@11637 589 thread->enter_critical();
never@11637 590 // Make sure the native wrapper calls back on return to
never@11637 591 // perform the needed critical unlock.
never@11637 592 thread->set_critical_native_unlock();
never@11637 593 }
never@11637 594 }
never@11637 595 }
never@11637 596 }
never@11637 597
never@11637 598
never@11637 599
duke@1 600 // -------------------------------------------------------------------------------------------------------
duke@1 601 // Implementation of Safepoint callback point
duke@1 602
duke@1 603 void SafepointSynchronize::block(JavaThread *thread) {
duke@1 604 assert(thread != NULL, "thread must be set");
duke@1 605 assert(thread->is_Java_thread(), "not a Java thread");
duke@1 606
duke@1 607 // Threads shouldn't block if they are in the middle of printing, but...
duke@1 608 ttyLocker::break_tty_lock_for_safepoint(os::current_thread_id());
duke@1 609
duke@1 610 // Only bail from the block() call if the thread is gone from the
duke@1 611 // thread list; starting to exit should still block.
duke@1 612 if (thread->is_terminated()) {
duke@1 613 // block current thread if we come here from native code when VM is gone
duke@1 614 thread->block_if_vm_exited();
duke@1 615
duke@1 616 // otherwise do nothing
duke@1 617 return;
duke@1 618 }
duke@1 619
duke@1 620 JavaThreadState state = thread->thread_state();
duke@1 621 thread->frame_anchor()->make_walkable(thread);
duke@1 622
duke@1 623 // Check that we have a valid thread_state at this point
duke@1 624 switch(state) {
duke@1 625 case _thread_in_vm_trans:
duke@1 626 case _thread_in_Java: // From compiled code
duke@1 627
duke@1 628 // We are highly likely to block on the Safepoint_lock. In order to avoid blocking in this case,
duke@1 629 // we pretend we are still in the VM.
duke@1 630 thread->set_thread_state(_thread_in_vm);
duke@1 631
duke@1 632 if (is_synchronizing()) {
duke@1 633 Atomic::inc (&TryingToBlock) ;
duke@1 634 }
duke@1 635
duke@1 636 // We will always be holding the Safepoint_lock when we are examine the state
duke@1 637 // of a thread. Hence, the instructions between the Safepoint_lock->lock() and
duke@1 638 // Safepoint_lock->unlock() are happening atomic with regards to the safepoint code
duke@1 639 Safepoint_lock->lock_without_safepoint_check();
duke@1 640 if (is_synchronizing()) {
duke@1 641 // Decrement the number of threads to wait for and signal vm thread
duke@1 642 assert(_waiting_to_block > 0, "sanity check");
duke@1 643 _waiting_to_block--;
duke@1 644 thread->safepoint_state()->set_has_called_back(true);
duke@1 645
never@12108 646 DEBUG_ONLY(thread->set_visited_for_critical_count(true));
never@11631 647 if (thread->in_critical()) {
never@11631 648 // Notice that this thread is in a critical section
never@11631 649 increment_jni_active_count();
never@11631 650 }
never@11631 651
duke@1 652 // Consider (_waiting_to_block < 2) to pipeline the wakeup of the VM thread
duke@1 653 if (_waiting_to_block == 0) {
duke@1 654 Safepoint_lock->notify_all();
duke@1 655 }
duke@1 656 }
duke@1 657
duke@1 658 // We transition the thread to state _thread_blocked here, but
duke@1 659 // we can't do our usual check for external suspension and then
duke@1 660 // self-suspend after the lock_without_safepoint_check() call
duke@1 661 // below because we are often called during transitions while
duke@1 662 // we hold different locks. That would leave us suspended while
duke@1 663 // holding a resource which results in deadlocks.
duke@1 664 thread->set_thread_state(_thread_blocked);
duke@1 665 Safepoint_lock->unlock();
duke@1 666
duke@1 667 // We now try to acquire the threads lock. Since this lock is hold by the VM thread during
duke@1 668 // the entire safepoint, the threads will all line up here during the safepoint.
duke@1 669 Threads_lock->lock_without_safepoint_check();
duke@1 670 // restore original state. This is important if the thread comes from compiled code, so it
duke@1 671 // will continue to execute with the _thread_in_Java state.
duke@1 672 thread->set_thread_state(state);
duke@1 673 Threads_lock->unlock();
duke@1 674 break;
duke@1 675
duke@1 676 case _thread_in_native_trans:
duke@1 677 case _thread_blocked_trans:
duke@1 678 case _thread_new_trans:
duke@1 679 if (thread->safepoint_state()->type() == ThreadSafepointState::_call_back) {
duke@1 680 thread->print_thread_state();
duke@1 681 fatal("Deadlock in safepoint code. "
duke@1 682 "Should have called back to the VM before blocking.");
duke@1 683 }
duke@1 684
duke@1 685 // We transition the thread to state _thread_blocked here, but
duke@1 686 // we can't do our usual check for external suspension and then
duke@1 687 // self-suspend after the lock_without_safepoint_check() call
duke@1 688 // below because we are often called during transitions while
duke@1 689 // we hold different locks. That would leave us suspended while
duke@1 690 // holding a resource which results in deadlocks.
duke@1 691 thread->set_thread_state(_thread_blocked);
duke@1 692
duke@1 693 // It is not safe to suspend a thread if we discover it is in _thread_in_native_trans. Hence,
duke@1 694 // the safepoint code might still be waiting for it to block. We need to change the state here,
duke@1 695 // so it can see that it is at a safepoint.
duke@1 696
duke@1 697 // Block until the safepoint operation is completed.
duke@1 698 Threads_lock->lock_without_safepoint_check();
duke@1 699
duke@1 700 // Restore state
duke@1 701 thread->set_thread_state(state);
duke@1 702
duke@1 703 Threads_lock->unlock();
duke@1 704 break;
duke@1 705
duke@1 706 default:
jcoomes@5403 707 fatal(err_msg("Illegal threadstate encountered: %d", state));
duke@1 708 }
duke@1 709
duke@1 710 // Check for pending. async. exceptions or suspends - except if the
duke@1 711 // thread was blocked inside the VM. has_special_runtime_exit_condition()
duke@1 712 // is called last since it grabs a lock and we only want to do that when
duke@1 713 // we must.
duke@1 714 //
duke@1 715 // Note: we never deliver an async exception at a polling point as the
duke@1 716 // compiler may not have an exception handler for it. The polling
duke@1 717 // code will notice the async and deoptimize and the exception will
duke@1 718 // be delivered. (Polling at a return point is ok though). Sure is
duke@1 719 // a lot of bother for a deprecated feature...
duke@1 720 //
duke@1 721 // We don't deliver an async exception if the thread state is
duke@1 722 // _thread_in_native_trans so JNI functions won't be called with
duke@1 723 // a surprising pending exception. If the thread state is going back to java,
duke@1 724 // async exception is checked in check_special_condition_for_native_trans().
duke@1 725
duke@1 726 if (state != _thread_blocked_trans &&
duke@1 727 state != _thread_in_vm_trans &&
duke@1 728 thread->has_special_runtime_exit_condition()) {
duke@1 729 thread->handle_special_runtime_exit_condition(
duke@1 730 !thread->is_at_poll_safepoint() && (state != _thread_in_native_trans));
duke@1 731 }
duke@1 732 }
duke@1 733
duke@1 734 // ------------------------------------------------------------------------------------------------------
duke@1 735 // Exception handlers
duke@1 736
duke@1 737 #ifndef PRODUCT
mikael@16670 738
mikael@16670 739 #ifdef SPARC
mikael@16670 740
duke@1 741 #ifdef _LP64
duke@1 742 #define PTR_PAD ""
duke@1 743 #else
duke@1 744 #define PTR_PAD " "
duke@1 745 #endif
duke@1 746
duke@1 747 static void print_ptrs(intptr_t oldptr, intptr_t newptr, bool wasoop) {
hseigel@20282 748 bool is_oop = newptr ? (cast_to_oop(newptr))->is_oop() : false;
duke@1 749 tty->print_cr(PTR_FORMAT PTR_PAD " %s %c " PTR_FORMAT PTR_PAD " %s %s",
duke@1 750 oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!',
duke@1 751 newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" "));
duke@1 752 }
duke@1 753
duke@1 754 static void print_longs(jlong oldptr, jlong newptr, bool wasoop) {
hseigel@20282 755 bool is_oop = newptr ? (cast_to_oop(newptr))->is_oop() : false;
duke@1 756 tty->print_cr(PTR64_FORMAT " %s %c " PTR64_FORMAT " %s %s",
duke@1 757 oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!',
duke@1 758 newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" "));
duke@1 759 }
duke@1 760
duke@1 761 static void print_me(intptr_t *new_sp, intptr_t *old_sp, bool *was_oops) {
duke@1 762 #ifdef _LP64
duke@1 763 tty->print_cr("--------+------address-----+------before-----------+-------after----------+");
duke@1 764 const int incr = 1; // Increment to skip a long, in units of intptr_t
duke@1 765 #else
duke@1 766 tty->print_cr("--------+--address-+------before-----------+-------after----------+");
duke@1 767 const int incr = 2; // Increment to skip a long, in units of intptr_t
duke@1 768 #endif
duke@1 769 tty->print_cr("---SP---|");
duke@1 770 for( int i=0; i<16; i++ ) {
duke@1 771 tty->print("blob %c%d |"PTR_FORMAT" ","LO"[i>>3],i&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); }
duke@1 772 tty->print_cr("--------|");
duke@1 773 for( int i1=0; i1<frame::memory_parameter_word_sp_offset-16; i1++ ) {
duke@1 774 tty->print("argv pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); }
duke@1 775 tty->print(" pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++);
duke@1 776 tty->print_cr("--------|");
duke@1 777 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;
duke@1 778 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;
duke@1 779 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;
duke@1 780 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;
duke@1 781 tty->print_cr(" FSR |"PTR_FORMAT" "PTR64_FORMAT" "PTR64_FORMAT,new_sp,*(jlong*)old_sp,*(jlong*)new_sp);
duke@1 782 old_sp += incr; new_sp += incr; was_oops += incr;
duke@1 783 // Skip the floats
duke@1 784 tty->print_cr("--Float-|"PTR_FORMAT,new_sp);
duke@1 785 tty->print_cr("---FP---|");
duke@1 786 old_sp += incr*32; new_sp += incr*32; was_oops += incr*32;
duke@1 787 for( int i2=0; i2<16; i2++ ) {
duke@1 788 tty->print("call %c%d |"PTR_FORMAT" ","LI"[i2>>3],i2&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); }
duke@1 789 tty->print_cr("");
duke@1 790 }
duke@1 791 #endif // SPARC
duke@1 792 #endif // PRODUCT
duke@1 793
duke@1 794
duke@1 795 void SafepointSynchronize::handle_polling_page_exception(JavaThread *thread) {
duke@1 796 assert(thread->is_Java_thread(), "polling reference encountered by VM thread");
duke@1 797 assert(thread->thread_state() == _thread_in_Java, "should come from Java code");
duke@1 798 assert(SafepointSynchronize::is_synchronizing(), "polling encountered outside safepoint synchronization");
duke@1 799
duke@1 800 // Uncomment this to get some serious before/after printing of the
duke@1 801 // Sparc safepoint-blob frame structure.
duke@1 802 /*
duke@1 803 intptr_t* sp = thread->last_Java_sp();
duke@1 804 intptr_t stack_copy[150];
duke@1 805 for( int i=0; i<150; i++ ) stack_copy[i] = sp[i];
duke@1 806 bool was_oops[150];
duke@1 807 for( int i=0; i<150; i++ )
duke@1 808 was_oops[i] = stack_copy[i] ? ((oop)stack_copy[i])->is_oop() : false;
duke@1 809 */
duke@1 810
duke@1 811 if (ShowSafepointMsgs) {
duke@1 812 tty->print("handle_polling_page_exception: ");
duke@1 813 }
duke@1 814
duke@1 815 if (PrintSafepointStatistics) {
duke@1 816 inc_page_trap_count();
duke@1 817 }
duke@1 818
duke@1 819 ThreadSafepointState* state = thread->safepoint_state();
duke@1 820
duke@1 821 state->handle_polling_page_exception();
duke@1 822 // print_me(sp,stack_copy,was_oops);
duke@1 823 }
duke@1 824
duke@1 825
duke@1 826 void SafepointSynchronize::print_safepoint_timeout(SafepointTimeoutReason reason) {
duke@1 827 if (!timeout_error_printed) {
duke@1 828 timeout_error_printed = true;
jwilhelm@22551 829 // Print out the thread info which didn't reach the safepoint for debugging
duke@1 830 // purposes (useful when there are lots of threads in the debugger).
duke@1 831 tty->print_cr("");
duke@1 832 tty->print_cr("# SafepointSynchronize::begin: Timeout detected:");
duke@1 833 if (reason == _spinning_timeout) {
duke@1 834 tty->print_cr("# SafepointSynchronize::begin: Timed out while spinning to reach a safepoint.");
duke@1 835 } else if (reason == _blocking_timeout) {
duke@1 836 tty->print_cr("# SafepointSynchronize::begin: Timed out while waiting for threads to stop.");
duke@1 837 }
duke@1 838
duke@1 839 tty->print_cr("# SafepointSynchronize::begin: Threads which did not reach the safepoint:");
duke@1 840 ThreadSafepointState *cur_state;
duke@1 841 ResourceMark rm;
duke@1 842 for(JavaThread *cur_thread = Threads::first(); cur_thread;
duke@1 843 cur_thread = cur_thread->next()) {
duke@1 844 cur_state = cur_thread->safepoint_state();
duke@1 845
duke@1 846 if (cur_thread->thread_state() != _thread_blocked &&
duke@1 847 ((reason == _spinning_timeout && cur_state->is_running()) ||
duke@1 848 (reason == _blocking_timeout && !cur_state->has_called_back()))) {
duke@1 849 tty->print("# ");
duke@1 850 cur_thread->print();
duke@1 851 tty->print_cr("");
duke@1 852 }
duke@1 853 }
duke@1 854 tty->print_cr("# SafepointSynchronize::begin: (End of list)");
duke@1 855 }
duke@1 856
duke@1 857 // To debug the long safepoint, specify both DieOnSafepointTimeout &
duke@1 858 // ShowMessageBoxOnError.
duke@1 859 if (DieOnSafepointTimeout) {
duke@1 860 char msg[1024];
duke@1 861 VM_Operation *op = VMThread::vm_operation();
xlu@1889 862 sprintf(msg, "Safepoint sync time longer than " INTX_FORMAT "ms detected when executing %s.",
duke@1 863 SafepointTimeoutDelay,
duke@1 864 op != NULL ? op->name() : "no vm operation");
duke@1 865 fatal(msg);
duke@1 866 }
duke@1 867 }
duke@1 868
duke@1 869
duke@1 870 // -------------------------------------------------------------------------------------------------------
duke@1 871 // Implementation of ThreadSafepointState
duke@1 872
duke@1 873 ThreadSafepointState::ThreadSafepointState(JavaThread *thread) {
duke@1 874 _thread = thread;
duke@1 875 _type = _running;
duke@1 876 _has_called_back = false;
duke@1 877 _at_poll_safepoint = false;
duke@1 878 }
duke@1 879
duke@1 880 void ThreadSafepointState::create(JavaThread *thread) {
duke@1 881 ThreadSafepointState *state = new ThreadSafepointState(thread);
duke@1 882 thread->set_safepoint_state(state);
duke@1 883 }
duke@1 884
duke@1 885 void ThreadSafepointState::destroy(JavaThread *thread) {
duke@1 886 if (thread->safepoint_state()) {
duke@1 887 delete(thread->safepoint_state());
duke@1 888 thread->set_safepoint_state(NULL);
duke@1 889 }
duke@1 890 }
duke@1 891
duke@1 892 void ThreadSafepointState::examine_state_of_thread() {
duke@1 893 assert(is_running(), "better be running or just have hit safepoint poll");
duke@1 894
duke@1 895 JavaThreadState state = _thread->thread_state();
duke@1 896
never@6269 897 // Save the state at the start of safepoint processing.
never@6269 898 _orig_thread_state = state;
never@6269 899
duke@1 900 // Check for a thread that is suspended. Note that thread resume tries
duke@1 901 // to grab the Threads_lock which we own here, so a thread cannot be
duke@1 902 // resumed during safepoint synchronization.
duke@1 903
dcubed@3826 904 // We check to see if this thread is suspended without locking to
dcubed@3826 905 // avoid deadlocking with a third thread that is waiting for this
dcubed@3826 906 // thread to be suspended. The third thread can notice the safepoint
dcubed@3826 907 // that we're trying to start at the beginning of its SR_lock->wait()
dcubed@3826 908 // call. If that happens, then the third thread will block on the
dcubed@3826 909 // safepoint while still holding the underlying SR_lock. We won't be
dcubed@3826 910 // able to get the SR_lock and we'll deadlock.
dcubed@3826 911 //
dcubed@3826 912 // We don't need to grab the SR_lock here for two reasons:
dcubed@3826 913 // 1) The suspend flags are both volatile and are set with an
dcubed@3826 914 // Atomic::cmpxchg() call so we should see the suspended
dcubed@3826 915 // state right away.
dcubed@3826 916 // 2) We're being called from the safepoint polling loop; if
dcubed@3826 917 // we don't see the suspended state on this iteration, then
dcubed@3826 918 // we'll come around again.
dcubed@3826 919 //
dcubed@3826 920 bool is_suspended = _thread->is_ext_suspended();
duke@1 921 if (is_suspended) {
duke@1 922 roll_forward(_at_safepoint);
duke@1 923 return;
duke@1 924 }
duke@1 925
duke@1 926 // Some JavaThread states have an initial safepoint state of
duke@1 927 // running, but are actually at a safepoint. We will happily
duke@1 928 // agree and update the safepoint state here.
duke@1 929 if (SafepointSynchronize::safepoint_safe(_thread, state)) {
never@12108 930 SafepointSynchronize::check_for_lazy_critical_native(_thread, state);
never@11631 931 roll_forward(_at_safepoint);
never@11631 932 return;
duke@1 933 }
duke@1 934
duke@1 935 if (state == _thread_in_vm) {
duke@1 936 roll_forward(_call_back);
duke@1 937 return;
duke@1 938 }
duke@1 939
duke@1 940 // All other thread states will continue to run until they
duke@1 941 // transition and self-block in state _blocked
duke@1 942 // Safepoint polling in compiled code causes the Java threads to do the same.
duke@1 943 // Note: new threads may require a malloc so they must be allowed to finish
duke@1 944
duke@1 945 assert(is_running(), "examine_state_of_thread on non-running thread");
duke@1 946 return;
duke@1 947 }
duke@1 948
duke@1 949 // Returns true is thread could not be rolled forward at present position.
duke@1 950 void ThreadSafepointState::roll_forward(suspend_type type) {
duke@1 951 _type = type;
duke@1 952
duke@1 953 switch(_type) {
duke@1 954 case _at_safepoint:
duke@1 955 SafepointSynchronize::signal_thread_at_safepoint();
never@12108 956 DEBUG_ONLY(_thread->set_visited_for_critical_count(true));
never@12108 957 if (_thread->in_critical()) {
never@12108 958 // Notice that this thread is in a critical section
never@12108 959 SafepointSynchronize::increment_jni_active_count();
never@12108 960 }
duke@1 961 break;
duke@1 962
duke@1 963 case _call_back:
duke@1 964 set_has_called_back(false);
duke@1 965 break;
duke@1 966
duke@1 967 case _running:
duke@1 968 default:
duke@1 969 ShouldNotReachHere();
duke@1 970 }
duke@1 971 }
duke@1 972
duke@1 973 void ThreadSafepointState::restart() {
duke@1 974 switch(type()) {
duke@1 975 case _at_safepoint:
duke@1 976 case _call_back:
duke@1 977 break;
duke@1 978
duke@1 979 case _running:
duke@1 980 default:
duke@1 981 tty->print_cr("restart thread "INTPTR_FORMAT" with state %d",
duke@1 982 _thread, _type);
duke@1 983 _thread->print();
duke@1 984 ShouldNotReachHere();
duke@1 985 }
duke@1 986 _type = _running;
duke@1 987 set_has_called_back(false);
duke@1 988 }
duke@1 989
duke@1 990
duke@1 991 void ThreadSafepointState::print_on(outputStream *st) const {
duke@1 992 const char *s;
duke@1 993
duke@1 994 switch(_type) {
duke@1 995 case _running : s = "_running"; break;
duke@1 996 case _at_safepoint : s = "_at_safepoint"; break;
duke@1 997 case _call_back : s = "_call_back"; break;
duke@1 998 default:
duke@1 999 ShouldNotReachHere();
duke@1 1000 }
duke@1 1001
duke@1 1002 st->print_cr("Thread: " INTPTR_FORMAT
duke@1 1003 " [0x%2x] State: %s _has_called_back %d _at_poll_safepoint %d",
duke@1 1004 _thread, _thread->osthread()->thread_id(), s, _has_called_back,
duke@1 1005 _at_poll_safepoint);
duke@1 1006
duke@1 1007 _thread->print_thread_state_on(st);
duke@1 1008 }
duke@1 1009
duke@1 1010
duke@1 1011 // ---------------------------------------------------------------------------------------------------------------------
duke@1 1012
duke@1 1013 // Block the thread at the safepoint poll or poll return.
duke@1 1014 void ThreadSafepointState::handle_polling_page_exception() {
duke@1 1015
duke@1 1016 // Check state. block() will set thread state to thread_in_vm which will
duke@1 1017 // cause the safepoint state _type to become _call_back.
duke@1 1018 assert(type() == ThreadSafepointState::_running,
duke@1 1019 "polling page exception on thread not running state");
duke@1 1020
duke@1 1021 // Step 1: Find the nmethod from the return address
duke@1 1022 if (ShowSafepointMsgs && Verbose) {
duke@1 1023 tty->print_cr("Polling page exception at " INTPTR_FORMAT, thread()->saved_exception_pc());
duke@1 1024 }
duke@1 1025 address real_return_addr = thread()->saved_exception_pc();
duke@1 1026
duke@1 1027 CodeBlob *cb = CodeCache::find_blob(real_return_addr);
duke@1 1028 assert(cb != NULL && cb->is_nmethod(), "return address should be in nmethod");
duke@1 1029 nmethod* nm = (nmethod*)cb;
duke@1 1030
duke@1 1031 // Find frame of caller
duke@1 1032 frame stub_fr = thread()->last_frame();
duke@1 1033 CodeBlob* stub_cb = stub_fr.cb();
duke@1 1034 assert(stub_cb->is_safepoint_stub(), "must be a safepoint stub");
duke@1 1035 RegisterMap map(thread(), true);
duke@1 1036 frame caller_fr = stub_fr.sender(&map);
duke@1 1037
duke@1 1038 // Should only be poll_return or poll
duke@1 1039 assert( nm->is_at_poll_or_poll_return(real_return_addr), "should not be at call" );
duke@1 1040
duke@1 1041 // This is a poll immediately before a return. The exception handling code
duke@1 1042 // has already had the effect of causing the return to occur, so the execution
duke@1 1043 // will continue immediately after the call. In addition, the oopmap at the
duke@1 1044 // return point does not mark the return value as an oop (if it is), so
duke@1 1045 // it needs a handle here to be updated.
duke@1 1046 if( nm->is_at_poll_return(real_return_addr) ) {
duke@1 1047 // See if return type is an oop.
duke@1 1048 bool return_oop = nm->method()->is_returning_oop();
duke@1 1049 Handle return_value;
duke@1 1050 if (return_oop) {
duke@1 1051 // The oop result has been saved on the stack together with all
duke@1 1052 // the other registers. In order to preserve it over GCs we need
duke@1 1053 // to keep it in a handle.
duke@1 1054 oop result = caller_fr.saved_oop_result(&map);
duke@1 1055 assert(result == NULL || result->is_oop(), "must be oop");
duke@1 1056 return_value = Handle(thread(), result);
duke@1 1057 assert(Universe::heap()->is_in_or_null(result), "must be heap pointer");
duke@1 1058 }
duke@1 1059
duke@1 1060 // Block the thread
duke@1 1061 SafepointSynchronize::block(thread());
duke@1 1062
duke@1 1063 // restore oop result, if any
duke@1 1064 if (return_oop) {
duke@1 1065 caller_fr.set_saved_oop_result(&map, return_value());
duke@1 1066 }
duke@1 1067 }
duke@1 1068
duke@1 1069 // This is a safepoint poll. Verify the return address and block.
duke@1 1070 else {
duke@1 1071 set_at_poll_safepoint(true);
duke@1 1072
duke@1 1073 // verify the blob built the "return address" correctly
duke@1 1074 assert(real_return_addr == caller_fr.pc(), "must match");
duke@1 1075
duke@1 1076 // Block the thread
duke@1 1077 SafepointSynchronize::block(thread());
duke@1 1078 set_at_poll_safepoint(false);
duke@1 1079
duke@1 1080 // If we have a pending async exception deoptimize the frame
duke@1 1081 // as otherwise we may never deliver it.
duke@1 1082 if (thread()->has_async_condition()) {
duke@1 1083 ThreadInVMfromJavaNoAsyncException __tiv(thread());
never@7106 1084 Deoptimization::deoptimize_frame(thread(), caller_fr.id());
duke@1 1085 }
duke@1 1086
duke@1 1087 // If an exception has been installed we must check for a pending deoptimization
duke@1 1088 // Deoptimize frame if exception has been thrown.
duke@1 1089
duke@1 1090 if (thread()->has_pending_exception() ) {
duke@1 1091 RegisterMap map(thread(), true);
duke@1 1092 frame caller_fr = stub_fr.sender(&map);
duke@1 1093 if (caller_fr.is_deoptimized_frame()) {
duke@1 1094 // The exception patch will destroy registers that are still
duke@1 1095 // live and will be needed during deoptimization. Defer the
jwilhelm@22551 1096 // Async exception should have deferred the exception until the
duke@1 1097 // next safepoint which will be detected when we get into
duke@1 1098 // the interpreter so if we have an exception now things
duke@1 1099 // are messed up.
duke@1 1100
duke@1 1101 fatal("Exception installed and deoptimization is pending");
duke@1 1102 }
duke@1 1103 }
duke@1 1104 }
duke@1 1105 }
duke@1 1106
duke@1 1107
duke@1 1108 //
duke@1 1109 // Statistics & Instrumentations
duke@1 1110 //
duke@1 1111 SafepointSynchronize::SafepointStats* SafepointSynchronize::_safepoint_stats = NULL;
xlu@5042 1112 jlong SafepointSynchronize::_safepoint_begin_time = 0;
duke@1 1113 int SafepointSynchronize::_cur_stat_index = 0;
duke@1 1114 julong SafepointSynchronize::_safepoint_reasons[VM_Operation::VMOp_Terminating];
duke@1 1115 julong SafepointSynchronize::_coalesced_vmop_count = 0;
duke@1 1116 jlong SafepointSynchronize::_max_sync_time = 0;
xlu@5042 1117 jlong SafepointSynchronize::_max_vmop_time = 0;
xlu@5042 1118 float SafepointSynchronize::_ts_of_current_safepoint = 0.0f;
duke@1 1119
xlu@5042 1120 static jlong cleanup_end_time = 0;
duke@1 1121 static bool need_to_track_page_armed_status = false;
duke@1 1122 static bool init_done = false;
duke@1 1123
xlu@5042 1124 // Helper method to print the header.
xlu@5042 1125 static void print_header() {
xlu@5042 1126 tty->print(" vmop "
xlu@5042 1127 "[threads: total initially_running wait_to_block] ");
xlu@5042 1128 tty->print("[time: spin block sync cleanup vmop] ");
xlu@5042 1129
xlu@5042 1130 // no page armed status printed out if it is always armed.
xlu@5042 1131 if (need_to_track_page_armed_status) {
xlu@5042 1132 tty->print("page_armed ");
xlu@5042 1133 }
xlu@5042 1134
xlu@5042 1135 tty->print_cr("page_trap_count");
xlu@5042 1136 }
xlu@5042 1137
duke@1 1138 void SafepointSynchronize::deferred_initialize_stat() {
duke@1 1139 if (init_done) return;
duke@1 1140
duke@1 1141 if (PrintSafepointStatisticsCount <= 0) {
duke@1 1142 fatal("Wrong PrintSafepointStatisticsCount");
duke@1 1143 }
duke@1 1144
duke@1 1145 // If PrintSafepointStatisticsTimeout is specified, the statistics data will
duke@1 1146 // be printed right away, in which case, _safepoint_stats will regress to
duke@1 1147 // a single element array. Otherwise, it is a circular ring buffer with default
duke@1 1148 // size of PrintSafepointStatisticsCount.
duke@1 1149 int stats_array_size;
duke@1 1150 if (PrintSafepointStatisticsTimeout > 0) {
duke@1 1151 stats_array_size = 1;
duke@1 1152 PrintSafepointStatistics = true;
duke@1 1153 } else {
duke@1 1154 stats_array_size = PrintSafepointStatisticsCount;
duke@1 1155 }
duke@1 1156 _safepoint_stats = (SafepointStats*)os::malloc(stats_array_size
zgu@13195 1157 * sizeof(SafepointStats), mtInternal);
duke@1 1158 guarantee(_safepoint_stats != NULL,
duke@1 1159 "not enough memory for safepoint instrumentation data");
duke@1 1160
duke@1 1161 if (UseCompilerSafepoints && DeferPollingPageLoopCount >= 0) {
duke@1 1162 need_to_track_page_armed_status = true;
duke@1 1163 }
duke@1 1164 init_done = true;
duke@1 1165 }
duke@1 1166
duke@1 1167 void SafepointSynchronize::begin_statistics(int nof_threads, int nof_running) {
xlu@4006 1168 assert(init_done, "safepoint statistics array hasn't been initialized");
duke@1 1169 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
duke@1 1170
xlu@5042 1171 spstat->_time_stamp = _ts_of_current_safepoint;
xlu@5042 1172
duke@1 1173 VM_Operation *op = VMThread::vm_operation();
duke@1 1174 spstat->_vmop_type = (op != NULL ? op->type() : -1);
duke@1 1175 if (op != NULL) {
duke@1 1176 _safepoint_reasons[spstat->_vmop_type]++;
duke@1 1177 }
duke@1 1178
duke@1 1179 spstat->_nof_total_threads = nof_threads;
duke@1 1180 spstat->_nof_initial_running_threads = nof_running;
duke@1 1181 spstat->_nof_threads_hit_page_trap = 0;
duke@1 1182
duke@1 1183 // Records the start time of spinning. The real time spent on spinning
duke@1 1184 // will be adjusted when spin is done. Same trick is applied for time
duke@1 1185 // spent on waiting for threads to block.
duke@1 1186 if (nof_running != 0) {
duke@1 1187 spstat->_time_to_spin = os::javaTimeNanos();
duke@1 1188 } else {
duke@1 1189 spstat->_time_to_spin = 0;
duke@1 1190 }
duke@1 1191 }
duke@1 1192
duke@1 1193 void SafepointSynchronize::update_statistics_on_spin_end() {
duke@1 1194 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
duke@1 1195
duke@1 1196 jlong cur_time = os::javaTimeNanos();
duke@1 1197
duke@1 1198 spstat->_nof_threads_wait_to_block = _waiting_to_block;
duke@1 1199 if (spstat->_nof_initial_running_threads != 0) {
duke@1 1200 spstat->_time_to_spin = cur_time - spstat->_time_to_spin;
duke@1 1201 }
duke@1 1202
duke@1 1203 if (need_to_track_page_armed_status) {
duke@1 1204 spstat->_page_armed = (PageArmed == 1);
duke@1 1205 }
duke@1 1206
duke@1 1207 // Records the start time of waiting for to block. Updated when block is done.
duke@1 1208 if (_waiting_to_block != 0) {
duke@1 1209 spstat->_time_to_wait_to_block = cur_time;
duke@1 1210 } else {
duke@1 1211 spstat->_time_to_wait_to_block = 0;
duke@1 1212 }
duke@1 1213 }
duke@1 1214
duke@1 1215 void SafepointSynchronize::update_statistics_on_sync_end(jlong end_time) {
duke@1 1216 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
duke@1 1217
duke@1 1218 if (spstat->_nof_threads_wait_to_block != 0) {
duke@1 1219 spstat->_time_to_wait_to_block = end_time -
duke@1 1220 spstat->_time_to_wait_to_block;
duke@1 1221 }
duke@1 1222
duke@1 1223 // Records the end time of sync which will be used to calculate the total
duke@1 1224 // vm operation time. Again, the real time spending in syncing will be deducted
duke@1 1225 // from the start of the sync time later when end_statistics is called.
xlu@5042 1226 spstat->_time_to_sync = end_time - _safepoint_begin_time;
duke@1 1227 if (spstat->_time_to_sync > _max_sync_time) {
duke@1 1228 _max_sync_time = spstat->_time_to_sync;
duke@1 1229 }
xlu@5042 1230
xlu@5042 1231 spstat->_time_to_do_cleanups = end_time;
xlu@5042 1232 }
xlu@5042 1233
xlu@5042 1234 void SafepointSynchronize::update_statistics_on_cleanup_end(jlong end_time) {
xlu@5042 1235 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
xlu@5042 1236
xlu@5042 1237 // Record how long spent in cleanup tasks.
xlu@5042 1238 spstat->_time_to_do_cleanups = end_time - spstat->_time_to_do_cleanups;
xlu@5042 1239
xlu@5042 1240 cleanup_end_time = end_time;
duke@1 1241 }
duke@1 1242
duke@1 1243 void SafepointSynchronize::end_statistics(jlong vmop_end_time) {
duke@1 1244 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
duke@1 1245
duke@1 1246 // Update the vm operation time.
xlu@5042 1247 spstat->_time_to_exec_vmop = vmop_end_time - cleanup_end_time;
xlu@5042 1248 if (spstat->_time_to_exec_vmop > _max_vmop_time) {
xlu@5042 1249 _max_vmop_time = spstat->_time_to_exec_vmop;
xlu@5042 1250 }
duke@1 1251 // Only the sync time longer than the specified
duke@1 1252 // PrintSafepointStatisticsTimeout will be printed out right away.
duke@1 1253 // By default, it is -1 meaning all samples will be put into the list.
duke@1 1254 if ( PrintSafepointStatisticsTimeout > 0) {
duke@1 1255 if (spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) {
duke@1 1256 print_statistics();
duke@1 1257 }
duke@1 1258 } else {
duke@1 1259 // The safepoint statistics will be printed out when the _safepoin_stats
duke@1 1260 // array fills up.
xlu@5042 1261 if (_cur_stat_index == PrintSafepointStatisticsCount - 1) {
duke@1 1262 print_statistics();
duke@1 1263 _cur_stat_index = 0;
xlu@5042 1264 } else {
xlu@5042 1265 _cur_stat_index++;
duke@1 1266 }
duke@1 1267 }
duke@1 1268 }
duke@1 1269
duke@1 1270 void SafepointSynchronize::print_statistics() {
duke@1 1271 SafepointStats* sstats = _safepoint_stats;
duke@1 1272
xlu@5042 1273 for (int index = 0; index <= _cur_stat_index; index++) {
xlu@5042 1274 if (index % 30 == 0) {
xlu@5042 1275 print_header();
xlu@5042 1276 }
duke@1 1277 sstats = &_safepoint_stats[index];
xlu@5042 1278 tty->print("%.3f: ", sstats->_time_stamp);
xlu@5042 1279 tty->print("%-26s ["
duke@1 1280 INT32_FORMAT_W(8)INT32_FORMAT_W(11)INT32_FORMAT_W(15)
xlu@5042 1281 " ] ",
duke@1 1282 sstats->_vmop_type == -1 ? "no vm operation" :
duke@1 1283 VM_Operation::name(sstats->_vmop_type),
duke@1 1284 sstats->_nof_total_threads,
duke@1 1285 sstats->_nof_initial_running_threads,
duke@1 1286 sstats->_nof_threads_wait_to_block);
duke@1 1287 // "/ MICROUNITS " is to convert the unit from nanos to millis.
xlu@5042 1288 tty->print(" ["
xlu@5042 1289 INT64_FORMAT_W(6)INT64_FORMAT_W(6)
xlu@5042 1290 INT64_FORMAT_W(6)INT64_FORMAT_W(6)
xlu@5042 1291 INT64_FORMAT_W(6)" ] ",
duke@1 1292 sstats->_time_to_spin / MICROUNITS,
duke@1 1293 sstats->_time_to_wait_to_block / MICROUNITS,
duke@1 1294 sstats->_time_to_sync / MICROUNITS,
xlu@5042 1295 sstats->_time_to_do_cleanups / MICROUNITS,
xlu@5042 1296 sstats->_time_to_exec_vmop / MICROUNITS);
duke@1 1297
duke@1 1298 if (need_to_track_page_armed_status) {
duke@1 1299 tty->print(INT32_FORMAT" ", sstats->_page_armed);
duke@1 1300 }
duke@1 1301 tty->print_cr(INT32_FORMAT" ", sstats->_nof_threads_hit_page_trap);
duke@1 1302 }
duke@1 1303 }
duke@1 1304
duke@1 1305 // This method will be called when VM exits. It will first call
duke@1 1306 // print_statistics to print out the rest of the sampling. Then
duke@1 1307 // it tries to summarize the sampling.
duke@1 1308 void SafepointSynchronize::print_stat_on_exit() {
duke@1 1309 if (_safepoint_stats == NULL) return;
duke@1 1310
duke@1 1311 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
duke@1 1312
duke@1 1313 // During VM exit, end_statistics may not get called and in that
duke@1 1314 // case, if the sync time is less than PrintSafepointStatisticsTimeout,
duke@1 1315 // don't print it out.
duke@1 1316 // Approximate the vm op time.
duke@1 1317 _safepoint_stats[_cur_stat_index]._time_to_exec_vmop =
xlu@5042 1318 os::javaTimeNanos() - cleanup_end_time;
duke@1 1319
duke@1 1320 if ( PrintSafepointStatisticsTimeout < 0 ||
duke@1 1321 spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) {
duke@1 1322 print_statistics();
duke@1 1323 }
duke@1 1324 tty->print_cr("");
duke@1 1325
duke@1 1326 // Print out polling page sampling status.
duke@1 1327 if (!need_to_track_page_armed_status) {
duke@1 1328 if (UseCompilerSafepoints) {
duke@1 1329 tty->print_cr("Polling page always armed");
duke@1 1330 }
duke@1 1331 } else {
duke@1 1332 tty->print_cr("Defer polling page loop count = %d\n",
duke@1 1333 DeferPollingPageLoopCount);
duke@1 1334 }
duke@1 1335
duke@1 1336 for (int index = 0; index < VM_Operation::VMOp_Terminating; index++) {
duke@1 1337 if (_safepoint_reasons[index] != 0) {
duke@1 1338 tty->print_cr("%-26s"UINT64_FORMAT_W(10), VM_Operation::name(index),
duke@1 1339 _safepoint_reasons[index]);
duke@1 1340 }
duke@1 1341 }
duke@1 1342
duke@1 1343 tty->print_cr(UINT64_FORMAT_W(5)" VM operations coalesced during safepoint",
duke@1 1344 _coalesced_vmop_count);
duke@1 1345 tty->print_cr("Maximum sync time "INT64_FORMAT_W(5)" ms",
duke@1 1346 _max_sync_time / MICROUNITS);
xlu@5042 1347 tty->print_cr("Maximum vm operation time (except for Exit VM operation) "
xlu@5042 1348 INT64_FORMAT_W(5)" ms",
xlu@5042 1349 _max_vmop_time / MICROUNITS);
duke@1 1350 }
duke@1 1351
duke@1 1352 // ------------------------------------------------------------------------------------------------
duke@1 1353 // Non-product code
duke@1 1354
duke@1 1355 #ifndef PRODUCT
duke@1 1356
duke@1 1357 void SafepointSynchronize::print_state() {
duke@1 1358 if (_state == _not_synchronized) {
duke@1 1359 tty->print_cr("not synchronized");
duke@1 1360 } else if (_state == _synchronizing || _state == _synchronized) {
duke@1 1361 tty->print_cr("State: %s", (_state == _synchronizing) ? "synchronizing" :
duke@1 1362 "synchronized");
duke@1 1363
duke@1 1364 for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) {
duke@1 1365 cur->safepoint_state()->print();
duke@1 1366 }
duke@1 1367 }
duke@1 1368 }
duke@1 1369
duke@1 1370 void SafepointSynchronize::safepoint_msg(const char* format, ...) {
duke@1 1371 if (ShowSafepointMsgs) {
duke@1 1372 va_list ap;
duke@1 1373 va_start(ap, format);
duke@1 1374 tty->vprint_cr(format, ap);
duke@1 1375 va_end(ap);
duke@1 1376 }
duke@1 1377 }
duke@1 1378
duke@1 1379 #endif // !PRODUCT