e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder# include "incls/_precompiled.incl"

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder# include "incls/_safepoint.cpp.incl"

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian MaederSafepointSynchronize::SynchronizeState volatile SafepointSynchronize::_state = SafepointSynchronize::_not_synchronized;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maedervolatile int SafepointSynchronize::_waiting_to_block = 0;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maedervolatile int SafepointSynchronize::_safepoint_counter = 0;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maederlong SafepointSynchronize::_end_of_last_safepoint = 0;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maederstatic volatile int PageArmed = 0 ; // safepoint polling page is RO|RW vs PROT_NONE

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maederstatic volatile int TryingToBlock = 0 ; // proximate value -- for advisory use only

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maederstatic bool timeout_error_printed = false;

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maedervoid SafepointSynchronize::begin() {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder Thread* myThread = Thread::current();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder assert(myThread->is_VM_thread(), "Only VM thread may execute a safepoint");

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (PrintSafepointStatistics || PrintSafepointStatisticsTimeout > 0) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder _safepoint_begin_time = os::javaTimeNanos();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder _ts_of_current_safepoint = tty->time_stamp().seconds();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder#ifndef SERIALGC

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (UseConcMarkSweepGC) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // In the future we should investigate whether CMS can use the

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // more-general mechanism below. DLD (01/05).

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder ConcurrentMarkSweepThread::synchronize(false);

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder } else if (UseG1GC) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder ConcurrentGCThread::safepoint_synchronize();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

02cbf7551685bc3b33f15f4cebfe9e9da1cae33eChristian Maeder#endif // SERIALGC

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // By getting the Threads_lock, we assure that no threads are about to start or

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // exit. It is released again in SafepointSynchronize::end().

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder Threads_lock->lock();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder assert( _state == _not_synchronized, "trying to safepoint synchronize with wrong state");

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder int nof_threads = Threads::number_of_threads();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (TraceSafepoint) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder tty->print_cr("Safepoint synchronization initiated. (%d)", nof_threads);

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder RuntimeService::record_safepoint_begin();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder MutexLocker mu(Safepoint_lock);

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Set number of threads to wait for, before we initiate the callbacks

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder _waiting_to_block = nof_threads;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder TryingToBlock = 0 ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder int still_running = nof_threads;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Save the starting time, so that it can be compared to see if this has taken

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // too long to complete.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder jlong safepoint_limit_time;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder timeout_error_printed = false;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // PrintSafepointStatisticsTimeout can be specified separately. When

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // specified, PrintSafepointStatistics will be set to true in

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // deferred_initialize_stat method. The initialization has to be done

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // early enough to avoid any races. See bug 6880029 for details.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (PrintSafepointStatistics || PrintSafepointStatisticsTimeout > 0) {

02cbf7551685bc3b33f15f4cebfe9e9da1cae33eChristian Maeder deferred_initialize_stat();

02cbf7551685bc3b33f15f4cebfe9e9da1cae33eChristian Maeder }

02cbf7551685bc3b33f15f4cebfe9e9da1cae33eChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // Begin the process of bringing the system to a safepoint.

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // Java threads can be in several different states and are

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // stopped by different mechanisms:

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder //

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // 1. Running interpreted

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // The interpeter dispatch table is changed to force it to

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // check for a safepoint condition between bytecodes.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // 2. Running in native code

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // When returning from the native code, a Java thread must check

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // the safepoint _state to see if we must block. If the

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // VM thread sees a Java thread in native, it does

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // not wait for this thread to block. The order of the memory

02cbf7551685bc3b33f15f4cebfe9e9da1cae33eChristian Maeder // writes and reads of both the safepoint state and the Java

02cbf7551685bc3b33f15f4cebfe9e9da1cae33eChristian Maeder // threads state is critical. In order to guarantee that the

02cbf7551685bc3b33f15f4cebfe9e9da1cae33eChristian Maeder // memory writes are serialized with respect to each other,

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // the VM thread issues a memory barrier instruction

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder // (on MP systems). In order to avoid the overhead of issuing

4561227a776bdf0ab679b19fb92f1eaaed8786f7Christian Maeder // a memory barrier for each Java thread making native calls, each Java

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder // thread performs a write to a single memory page after changing

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder // the thread state. The VM thread performs a sequence of

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder // mprotect OS calls which forces all previous writes from all

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Java threads to be serialized. This is done in the

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // os::serialize_thread_states() call. This has proven to be

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // much more efficient than executing a membar instruction

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // on every call to native code.

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // 3. Running compiled Code

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // Compiled code reads a global (Safepoint Polling) page that

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // is set to fault if we are trying to get to a safepoint.

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder // 4. Blocked

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder // A thread which is blocked will not be allowed to return from the

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // block condition until the safepoint operation is complete.

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder // 5. In VM or Transitioning between states

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder // If a Java thread is currently running in the VM or transitioning

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // between states, the safepointing code will wait for the thread to

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // block itself when it attempts transitions to a new state.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder //

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder _state = _synchronizing;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder OrderAccess::fence();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Flush all thread states to memory

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder if (!UseMembar) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder os::serialize_thread_states();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Make interpreter safepoint aware

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder Interpreter::notice_safepoints();

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (UseCompilerSafepoints && DeferPollingPageLoopCount < 0) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Make polling safepoint aware

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder guarantee (PageArmed == 0, "invariant") ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder PageArmed = 1 ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder os::make_polling_page_unreadable();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Consider using active_processor_count() ... but that call is expensive.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder int ncpus = os::processor_count() ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder#ifdef ASSERT

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder assert(cur->safepoint_state()->is_running(), "Illegal initial state");

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder#endif // ASSERT

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (SafepointTimeout)

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder safepoint_limit_time = os::javaTimeNanos() + (jlong)SafepointTimeoutDelay * MICROUNITS;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Iterate through all threads until it have been determined how to stop them all at a safepoint

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder unsigned int iterations = 0;

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder int steps = 0 ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder while(still_running > 0) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder assert(!cur->is_ConcurrentGC_thread(), "A concurrent GC thread is unexpectly being suspended");

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder ThreadSafepointState *cur_state = cur->safepoint_state();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (cur_state->is_running()) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder cur_state->examine_state_of_thread();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (!cur_state->is_running()) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder still_running--;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // consider adjusting steps downward:

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // steps = 0

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // steps -= NNN

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // steps >>= 1

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // steps = MIN(steps, 2000-100)

710aac293d45bd34d3690944701a879828ee5dc6Christian Maeder // if (iterations != 0) steps -= NNN

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder if (TraceSafepoint && Verbose) cur_state->print();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (PrintSafepointStatistics && iterations == 0) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder begin_statistics(nof_threads, still_running);

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder if (still_running > 0) {

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder // Check for if it takes to long

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder if (SafepointTimeout && safepoint_limit_time < os::javaTimeNanos()) {

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder print_safepoint_timeout(_spinning_timeout);

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder }

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // Spin to avoid context switching.

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder // There's a tension between allowing the mutators to run (and rendezvous)

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // vs spinning. As the VM thread spins, wasting cycles, it consumes CPU that

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // a mutator might otherwise use profitably to reach a safepoint. Excessive

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // spinning by the VM thread on a saturated system can increase rendezvous latency.

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder // Blocking or yielding incur their own penalties in the form of context switching

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder // and the resultant loss of $ residency.

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder //

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder // Further complicating matters is that yield() does not work as naively expected

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // on many platforms -- yield() does not guarantee that any other ready threads

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // will run. As such we revert yield_all() after some number of iterations.

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // Yield_all() is implemented as a short unconditional sleep on some platforms.

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // Typical operating systems round a "short" sleep period up to 10 msecs, so sleeping

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // can actually increase the time it takes the VM thread to detect that a system-wide

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // stop-the-world safepoint has been reached. In a pathological scenario such as that

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder // described in CR6415670 the VMthread may sleep just before the mutator(s) become safe.

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder // In that case the mutators will be stalled waiting for the safepoint to complete and the

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // the VMthread will be sleeping, waiting for the mutators to rendezvous. The VMthread

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // will eventually wake up and detect that all mutators are safe, at which point

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // we'll again make progress.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder //

b1ddd2f41ea1dfac428a366c5c3d413470dcbcfaChristian Maeder // Beware too that that the VMThread typically runs at elevated priority.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Its default priority is higher than the default mutator priority.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Obviously, this complicates spinning.

b1ddd2f41ea1dfac428a366c5c3d413470dcbcfaChristian Maeder //

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Note too that on Windows XP SwitchThreadTo() has quite different behavior than Sleep(0).

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Sleep(0) will _not yield to lower priority threads, while SwitchThreadTo() will.

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder //

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // See the comments in synchronizer.cpp for additional remarks on spinning.

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder //

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // In the future we might:

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // 1. Modify the safepoint scheme to avoid potentally unbounded spinning.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // This is tricky as the path used by a thread exiting the JVM (say on

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // on JNI call-out) simply stores into its state field. The burden

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // is placed on the VM thread, which must poll (spin).

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // 2. Find something useful to do while spinning. If the safepoint is GC-related

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // we might aggressively scan the stacks of threads that are already safe.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // 3. Use Solaris schedctl to examine the state of the still-running mutators.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // If all the mutators are ONPROC there's no reason to sleep or yield.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // 4. YieldTo() any still-running mutators that are ready but OFFPROC.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // 5. Check system saturation. If the system is not fully saturated then

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // simply spin and avoid sleep/yield.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // 6. As still-running mutators rendezvous they could unpark the sleeping

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // VMthread. This works well for still-running mutators that become

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // safe. The VMthread must still poll for mutators that call-out.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // 7. Drive the policy on time-since-begin instead of iterations.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // 8. Consider making the spin duration a function of the # of CPUs:

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Spin = (((ncpus-1) * M) + K) + F(still_running)

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Alternately, instead of counting iterations of the outer loop

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // we could count the # of threads visited in the inner loop, above.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // 9. On windows consider using the return value from SwitchThreadTo()

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // to drive subsequent spin/SwitchThreadTo()/Sleep(N) decisions.

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (UseCompilerSafepoints && int(iterations) == DeferPollingPageLoopCount) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder guarantee (PageArmed == 0, "invariant") ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder PageArmed = 1 ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder os::make_polling_page_unreadable();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Instead of (ncpus > 1) consider either (still_running < (ncpus + EPSILON)) or

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // ((still_running + _waiting_to_block - TryingToBlock)) < ncpus)

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder ++steps ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (ncpus > 1 && steps < SafepointSpinBeforeYield) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder SpinPause() ; // MP-Polite spin

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder } else

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (steps < DeferThrSuspendLoopCount) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder os::NakedYield() ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder } else {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder os::yield_all(steps) ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Alternately, the VM thread could transiently depress its scheduling priority or

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // transiently increase the priority of the tardy mutator(s).

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder iterations ++ ;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder assert(iterations < (uint)max_jint, "We have been iterating in the safepoint loop too long");

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder assert(still_running == 0, "sanity check");

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (PrintSafepointStatistics) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder update_statistics_on_spin_end();

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // wait until all threads are stopped

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder while (_waiting_to_block > 0) {

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder if (TraceSafepoint) tty->print_cr("Waiting for %d thread(s) to block", _waiting_to_block);

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder if (!SafepointTimeout || timeout_error_printed) {

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder Safepoint_lock->wait(true); // true, means with no safepoint checks

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder } else {

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // Compute remaining time

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder jlong remaining_time = safepoint_limit_time - os::javaTimeNanos();

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // If there is no remaining time, then there is an error

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder if (remaining_time < 0 || Safepoint_lock->wait(true, remaining_time / MICROUNITS)) {

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder print_safepoint_timeout(_blocking_timeout);

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder }

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder }

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder }

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder assert(_waiting_to_block == 0, "sanity check");

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder#ifndef PRODUCT

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder if (SafepointTimeout) {

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder jlong current_time = os::javaTimeNanos();

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder if (safepoint_limit_time < current_time) {

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder tty->print_cr("# SafepointSynchronize: Finished after "

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder INT64_FORMAT_W(6) " ms",

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder ((current_time - safepoint_limit_time) / MICROUNITS +

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder SafepointTimeoutDelay));

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder#endif

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder assert((_safepoint_counter & 0x1) == 0, "must be even");

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder assert(Threads_lock->owned_by_self(), "must hold Threads_lock");

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder _safepoint_counter ++;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Record state

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder _state = _synchronized;

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder OrderAccess::fence();

02cbf7551685bc3b33f15f4cebfe9e9da1cae33eChristian Maeder

02cbf7551685bc3b33f15f4cebfe9e9da1cae33eChristian Maeder if (TraceSafepoint) {

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder VM_Operation *op = VMThread::vm_operation();

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder tty->print_cr("Entering safepoint region: %s", (op != NULL) ? op->name() : "no vm operation");

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder }

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder

02cbf7551685bc3b33f15f4cebfe9e9da1cae33eChristian Maeder RuntimeService::record_safepoint_synchronized();

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder if (PrintSafepointStatistics) {

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder update_statistics_on_sync_end(os::javaTimeNanos());

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder }

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder

e6d733e9ab4fb48cb611637528e5694d1e092de0Christian Maeder // Call stuff that needs to be run when a safepoint is just about to be completed

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder do_cleanup_tasks();

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder if (PrintSafepointStatistics) {

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder // Record how much time spend on the above cleanup tasks

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder update_statistics_on_cleanup_end(os::javaTimeNanos());

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder }

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder }

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder}

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maedervoid SafepointSynchronize::end() {

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder assert(Threads_lock->owned_by_self(), "must hold Threads_lock");

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder assert((_safepoint_counter & 0x1) == 1, "must be odd");

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder _safepoint_counter ++;

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // memory fence isn't required here since an odd _safepoint_counter

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // value can do no harm and a fence is issued below anyway.

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder DEBUG_ONLY(Thread* myThread = Thread::current();)

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder assert(myThread->is_VM_thread(), "Only VM thread can execute a safepoint");

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder if (PrintSafepointStatistics) {

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder end_statistics(os::javaTimeNanos());

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder }

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder#ifdef ASSERT

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder // A pending_exception cannot be installed during a safepoint. The threads

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder // may install an async exception after they come back from a safepoint into

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder // pending_exception after they unblock. But that should happen later.

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) {

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder assert (!(cur->has_pending_exception() &&

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder cur->safepoint_state()->is_at_poll_safepoint()),

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder "safepoint installed a pending exception");

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder }

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder#endif // ASSERT

4542eacf3e35ca3b52de55effecd2ffb3aef96b6Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder if (PageArmed) {

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // Make polling safepoint aware

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder os::make_polling_page_readable();

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder PageArmed = 0 ;

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder }

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // Remove safepoint check from interpreter

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder Interpreter::ignore_safepoints();

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder {

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder MutexLocker mu(Safepoint_lock);

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder assert(_state == _synchronized, "must be synchronized before ending safepoint synchronization");

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder // Set to not synchronized, so the threads will not go into the signal_thread_blocked method

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // when they get restarted.

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder _state = _not_synchronized;

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder OrderAccess::fence();

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder if (TraceSafepoint) {

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder tty->print_cr("Leaving safepoint region");

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder }

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // Start suspended threads

f82f141a6b1639a50064a6e66b14f7823220b5d5Christian Maeder for(JavaThread *current = Threads::first(); current; current = current->next()) {

f82f141a6b1639a50064a6e66b14f7823220b5d5Christian Maeder // A problem occurring on Solaris is when attempting to restart threads

f82f141a6b1639a50064a6e66b14f7823220b5d5Christian Maeder // the first #cpus - 1 go well, but then the VMThread is preempted when we get

f82f141a6b1639a50064a6e66b14f7823220b5d5Christian Maeder // to the next one (since it has been running the longest). We then have

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // to wait for a cpu to become available before we can continue restarting

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // threads.

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder // FIXME: This causes the performance of the VM to degrade when active and with

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // large numbers of threads. Apparently this is due to the synchronous nature

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // of suspending threads.

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder //

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // TODO-FIXME: the comments above are vestigial and no longer apply.

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // Furthermore, using solaris' schedctl in this particular context confers no benefit

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder if (VMThreadHintNoPreempt) {

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder os::hint_no_preempt();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder }

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder ThreadSafepointState* cur_state = current->safepoint_state();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder assert(cur_state->type() != ThreadSafepointState::_running, "Thread not suspended at safepoint");

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder cur_state->restart();

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder assert(cur_state->is_running(), "safepoint state has not been reset");

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder }

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder RuntimeService::record_safepoint_end();

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder // Release threads lock, so threads can be created/destroyed again. It will also starts all threads

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // blocked in signal_thread_blocked

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder Threads_lock->unlock();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder }

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder#ifndef SERIALGC

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // If there are any concurrent GC threads resume them.

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder if (UseConcMarkSweepGC) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder ConcurrentMarkSweepThread::desynchronize(false);

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder } else if (UseG1GC) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder ConcurrentGCThread::safepoint_desynchronize();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder }

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder#endif // SERIALGC

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // record this time so VMThread can keep track how much time has elasped

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder // since last safepoint.

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder _end_of_last_safepoint = os::javaTimeMillis();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder}

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maederbool SafepointSynchronize::is_cleanup_needed() {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // Need a safepoint if some inline cache buffers is non-empty

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder if (!InlineCacheBuffer::is_empty()) return true;

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder return false;

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder}

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maederjlong CounterDecay::_last_timestamp = 0;

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maederstatic void do_method(methodOop m) {

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder m->invocation_counter()->decay();

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder}

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maedervoid CounterDecay::decay() {

a326c4a2e1bb141ada3b3072f5c7be86700005f2Christian Maeder _last_timestamp = os::javaTimeMillis();

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // This operation is going to be performed only at the end of a safepoint

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // and hence GC's will not be going on, all Java mutators are suspended

a326c4a2e1bb141ada3b3072f5c7be86700005f2Christian Maeder // at this point and hence SystemDictionary_lock is also not needed.

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder assert(SafepointSynchronize::is_at_safepoint(), "can only be executed at a safepoint");

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder int nclasses = SystemDictionary::number_of_classes();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder double classes_per_tick = nclasses * (CounterDecayMinIntervalLength * 1e-3 /

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder CounterHalfLifeTime);

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder for (int i = 0; i < classes_per_tick; i++) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder klassOop k = SystemDictionary::try_get_next_class();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder if (k != NULL && k->klass_part()->oop_is_instance()) {

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder instanceKlass::cast(k)->methods_do(do_method);

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder }

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder }

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder}

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maedervoid SafepointSynchronize::do_cleanup_tasks() {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder TraceTime t1("deflating idle monitors", TraceSafepointCleanupTime);

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder ObjectSynchronizer::deflate_idle_monitors();

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder }

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder {

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder TraceTime t2("updating inline caches", TraceSafepointCleanupTime);

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder InlineCacheBuffer::update_inline_caches();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder }

a326c4a2e1bb141ada3b3072f5c7be86700005f2Christian Maeder

a326c4a2e1bb141ada3b3072f5c7be86700005f2Christian Maeder if(UseCounterDecay && CounterDecay::is_decay_needed()) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder TraceTime t3("decaying counter", TraceSafepointCleanupTime);

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder CounterDecay::decay();

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder }

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder TraceTime t4("sweeping nmethods", TraceSafepointCleanupTime);

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder NMethodSweeper::scan_stacks();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder}

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maederbool SafepointSynchronize::safepoint_safe(JavaThread *thread, JavaThreadState state) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder switch(state) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder case _thread_in_native:

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder // native threads are safe if they have no java stack or have walkable stack

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder return !thread->has_last_Java_frame() || thread->frame_anchor()->walkable();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder // blocked threads should have already have walkable stack

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder case _thread_blocked:

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "blocked and not walkable");

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder return true;

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder default:

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder return false;

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder }

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder}

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maedervoid SafepointSynchronize::block(JavaThread *thread) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder assert(thread != NULL, "thread must be set");

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder assert(thread->is_Java_thread(), "not a Java thread");

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // Threads shouldn't block if they are in the middle of printing, but...

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder ttyLocker::break_tty_lock_for_safepoint(os::current_thread_id());

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // Only bail from the block() call if the thread is gone from the

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // thread list; starting to exit should still block.

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder if (thread->is_terminated()) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // block current thread if we come here from native code when VM is gone

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder thread->block_if_vm_exited();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // otherwise do nothing

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder return;

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder }

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder JavaThreadState state = thread->thread_state();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder thread->frame_anchor()->make_walkable(thread);

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // Check that we have a valid thread_state at this point

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder switch(state) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder case _thread_in_vm_trans:

a326c4a2e1bb141ada3b3072f5c7be86700005f2Christian Maeder case _thread_in_Java: // From compiled code

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // We are highly likely to block on the Safepoint_lock. In order to avoid blocking in this case,

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder // we pretend we are still in the VM.

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder thread->set_thread_state(_thread_in_vm);

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder if (is_synchronizing()) {

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder Atomic::inc (&TryingToBlock) ;

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder }

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // We will always be holding the Safepoint_lock when we are examine the state

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // of a thread. Hence, the instructions between the Safepoint_lock->lock() and

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // Safepoint_lock->unlock() are happening atomic with regards to the safepoint code

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder Safepoint_lock->lock_without_safepoint_check();

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder if (is_synchronizing()) {

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // Decrement the number of threads to wait for and signal vm thread

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder assert(_waiting_to_block > 0, "sanity check");

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder _waiting_to_block--;

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder thread->safepoint_state()->set_has_called_back(true);

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // Consider (_waiting_to_block < 2) to pipeline the wakeup of the VM thread

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder if (_waiting_to_block == 0) {

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder Safepoint_lock->notify_all();

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder }

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder }

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // We transition the thread to state _thread_blocked here, but

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // we can't do our usual check for external suspension and then

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // self-suspend after the lock_without_safepoint_check() call

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // below because we are often called during transitions while

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // we hold different locks. That would leave us suspended while

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // holding a resource which results in deadlocks.

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder thread->set_thread_state(_thread_blocked);

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder Safepoint_lock->unlock();

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // We now try to acquire the threads lock. Since this lock is hold by the VM thread during

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // the entire safepoint, the threads will all line up here during the safepoint.

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder Threads_lock->lock_without_safepoint_check();

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // restore original state. This is important if the thread comes from compiled code, so it

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // will continue to execute with the _thread_in_Java state.

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder thread->set_thread_state(state);

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder Threads_lock->unlock();

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder break;

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder case _thread_in_native_trans:

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder case _thread_blocked_trans:

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder case _thread_new_trans:

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder if (thread->safepoint_state()->type() == ThreadSafepointState::_call_back) {

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder thread->print_thread_state();

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder fatal("Deadlock in safepoint code. "

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder "Should have called back to the VM before blocking.");

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder }

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder // We transition the thread to state _thread_blocked here, but

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder // we can't do our usual check for external suspension and then

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // self-suspend after the lock_without_safepoint_check() call

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder // below because we are often called during transitions while

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // we hold different locks. That would leave us suspended while

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // holding a resource which results in deadlocks.

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder thread->set_thread_state(_thread_blocked);

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // It is not safe to suspend a thread if we discover it is in _thread_in_native_trans. Hence,

a326c4a2e1bb141ada3b3072f5c7be86700005f2Christian Maeder // the safepoint code might still be waiting for it to block. We need to change the state here,

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder // so it can see that it is at a safepoint.

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder // Block until the safepoint operation is completed.

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder Threads_lock->lock_without_safepoint_check();

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder // Restore state

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder thread->set_thread_state(state);

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder Threads_lock->unlock();

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder break;

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder default:

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder fatal(err_msg("Illegal threadstate encountered: %d", state));

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder }

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder // Check for pending. async. exceptions or suspends - except if the

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder // thread was blocked inside the VM. has_special_runtime_exit_condition()

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder // is called last since it grabs a lock and we only want to do that when

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder // we must.

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder //

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder // Note: we never deliver an async exception at a polling point as the

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // compiler may not have an exception handler for it. The polling

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder // code will notice the async and deoptimize and the exception will

4eef141c429d6ac5127ebcc4cd37367a5c70b0aaChristian Maeder // be delivered. (Polling at a return point is ok though). Sure is

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder // a lot of bother for a deprecated feature...

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder //

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder // We don't deliver an async exception if the thread state is

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder // _thread_in_native_trans so JNI functions won't be called with

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder // a surprising pending exception. If the thread state is going back to java,

4eef141c429d6ac5127ebcc4cd37367a5c70b0aaChristian Maeder // async exception is checked in check_special_condition_for_native_trans().

641e694a165a5f08c26c4b708ae549224f2e5beeChristian Maeder

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder if (state != _thread_blocked_trans &&

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder state != _thread_in_vm_trans &&

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder thread->has_special_runtime_exit_condition()) {

4eef141c429d6ac5127ebcc4cd37367a5c70b0aaChristian Maeder thread->handle_special_runtime_exit_condition(

4eef141c429d6ac5127ebcc4cd37367a5c70b0aaChristian Maeder !thread->is_at_poll_safepoint() && (state != _thread_in_native_trans));

710aac293d45bd34d3690944701a879828ee5dc6Christian Maeder }

4eef141c429d6ac5127ebcc4cd37367a5c70b0aaChristian Maeder}

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder#ifndef PRODUCT

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder#ifdef _LP64

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder#define PTR_PAD ""

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder#else

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder#define PTR_PAD " "

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder#endif

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maederstatic void print_ptrs(intptr_t oldptr, intptr_t newptr, bool wasoop) {

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder bool is_oop = newptr ? ((oop)newptr)->is_oop() : false;

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder tty->print_cr(PTR_FORMAT PTR_PAD " %s %c " PTR_FORMAT PTR_PAD " %s %s",

4eef141c429d6ac5127ebcc4cd37367a5c70b0aaChristian Maeder oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!',

4eef141c429d6ac5127ebcc4cd37367a5c70b0aaChristian Maeder newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" "));

9818ec2fd12dd08c36cedfb75473ccb970a5eb62Christian Maeder}

39366a8c5aa917040fcc6360841277e33da0d605Christian Maeder

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maederstatic void print_longs(jlong oldptr, jlong newptr, bool wasoop) {

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder bool is_oop = newptr ? ((oop)(intptr_t)newptr)->is_oop() : false;

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder tty->print_cr(PTR64_FORMAT " %s %c " PTR64_FORMAT " %s %s",

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!',

710aac293d45bd34d3690944701a879828ee5dc6Christian Maeder newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" "));

615ef723f845e48d74cd88934738ac9ba76de0b3Christian Maeder}

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder#ifdef SPARC

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maederstatic void print_me(intptr_t *new_sp, intptr_t *old_sp, bool *was_oops) {

710aac293d45bd34d3690944701a879828ee5dc6Christian Maeder#ifdef _LP64

710aac293d45bd34d3690944701a879828ee5dc6Christian Maeder tty->print_cr("--------+------address-----+------before-----------+-------after----------+");

710aac293d45bd34d3690944701a879828ee5dc6Christian Maeder const int incr = 1; // Increment to skip a long, in units of intptr_t

710aac293d45bd34d3690944701a879828ee5dc6Christian Maeder#else

710aac293d45bd34d3690944701a879828ee5dc6Christian Maeder tty->print_cr("--------+--address-+------before-----------+-------after----------+");

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder const int incr = 2; // Increment to skip a long, in units of intptr_t

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder#endif

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder tty->print_cr("---SP---|");

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder for( int i=0; i<16; i++ ) {

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder tty->print("blob %c%d |"PTR_FORMAT" ","LO"[i>>3],i&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); }

6e557a0d5e166ce87867876444a793bc9296b14aChristian Maeder tty->print_cr("--------|");

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder for( int i1=0; i1<frame::memory_parameter_word_sp_offset-16; i1++ ) {

4c20d89b174474beb5f38cc4d47b1ff983c676a9Christian Maeder tty->print("argv pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); }

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder tty->print(" pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++);

710aac293d45bd34d3690944701a879828ee5dc6Christian Maeder tty->print_cr("--------|");

710aac293d45bd34d3690944701a879828ee5dc6Christian Maeder 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;

76647324ed70f33b95a881b536d883daccf9568dChristian Maeder 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;

a86b847d6ea0bc06d90cb01db0ac4e654d13ee98Christian Maeder 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;

d049e21661c3d0a2cf6339d3b94e4cd188b0188cChristian Maeder 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;

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder tty->print_cr(" FSR |"PTR_FORMAT" "PTR64_FORMAT" "PTR64_FORMAT,new_sp,*(jlong*)old_sp,*(jlong*)new_sp);

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder old_sp += incr; new_sp += incr; was_oops += incr;

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder // Skip the floats

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder tty->print_cr("--Float-|"PTR_FORMAT,new_sp);

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder tty->print_cr("---FP---|");

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder old_sp += incr*32; new_sp += incr*32; was_oops += incr*32;

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder for( int i2=0; i2<16; i2++ ) {

4561227a776bdf0ab679b19fb92f1eaaed8786f7Christian Maeder tty->print("call %c%d |"PTR_FORMAT" ","LI"[i2>>3],i2&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); }

4561227a776bdf0ab679b19fb92f1eaaed8786f7Christian Maeder tty->print_cr("");

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder}

f82f141a6b1639a50064a6e66b14f7823220b5d5Christian Maeder#endif // SPARC

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder#endif // PRODUCT

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder

af48251d509031fd4ee846da43cab43844751cf7Christian Maedervoid SafepointSynchronize::handle_polling_page_exception(JavaThread *thread) {

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder assert(thread->is_Java_thread(), "polling reference encountered by VM thread");

11a8f0b56c43688f967c4f592db6807d9f279f42Christian Maeder assert(thread->thread_state() == _thread_in_Java, "should come from Java code");

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder assert(SafepointSynchronize::is_synchronizing(), "polling encountered outside safepoint synchronization");

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder // Uncomment this to get some serious before/after printing of the

f82f141a6b1639a50064a6e66b14f7823220b5d5Christian Maeder // Sparc safepoint-blob frame structure.

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder /*

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder if (ShowSafepointMsgs) {

f4a4521a8d3f171834ab351d1ac336c1898ece25Christian Maeder tty->print("handle_polling_page_exception: ");

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder }

4561227a776bdf0ab679b19fb92f1eaaed8786f7Christian Maeder

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder if (PrintSafepointStatistics) {

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder inc_page_trap_count();

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder }

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder ThreadSafepointState* state = thread->safepoint_state();

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder state->handle_polling_page_exception();

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder // print_me(sp,stack_copy,was_oops);

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder}

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder

af48251d509031fd4ee846da43cab43844751cf7Christian Maedervoid SafepointSynchronize::print_safepoint_timeout(SafepointTimeoutReason reason) {

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder if (!timeout_error_printed) {

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder timeout_error_printed = true;

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder // Print out the thread infor which didn't reach the safepoint for debugging

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder // purposes (useful when there are lots of threads in the debugger).

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder tty->print_cr("");

a326c4a2e1bb141ada3b3072f5c7be86700005f2Christian Maeder tty->print_cr("# SafepointSynchronize::begin: Timeout detected:");

a326c4a2e1bb141ada3b3072f5c7be86700005f2Christian Maeder if (reason == _spinning_timeout) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder tty->print_cr("# SafepointSynchronize::begin: Timed out while spinning to reach a safepoint.");

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder } else if (reason == _blocking_timeout) {

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder tty->print_cr("# SafepointSynchronize::begin: Timed out while waiting for threads to stop.");

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder }

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder tty->print_cr("# SafepointSynchronize::begin: Threads which did not reach the safepoint:");

b1ddd2f41ea1dfac428a366c5c3d413470dcbcfaChristian Maeder ThreadSafepointState *cur_state;

a326c4a2e1bb141ada3b3072f5c7be86700005f2Christian Maeder ResourceMark rm;

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder for(JavaThread *cur_thread = Threads::first(); cur_thread;

4561227a776bdf0ab679b19fb92f1eaaed8786f7Christian Maeder cur_thread = cur_thread->next()) {

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder cur_state = cur_thread->safepoint_state();

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder if (cur_thread->thread_state() != _thread_blocked &&

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder ((reason == _spinning_timeout && cur_state->is_running()) ||

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder (reason == _blocking_timeout && !cur_state->has_called_back()))) {

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder tty->print("# ");

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder cur_thread->print();

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder tty->print_cr("");

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder }

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder }

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder tty->print_cr("# SafepointSynchronize::begin: (End of list)");

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder }

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder // To debug the long safepoint, specify both DieOnSafepointTimeout &

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder // ShowMessageBoxOnError.

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder if (DieOnSafepointTimeout) {

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder char msg[1024];

af48251d509031fd4ee846da43cab43844751cf7Christian Maeder VM_Operation *op = VMThread::vm_operation();

11a8f0b56c43688f967c4f592db6807d9f279f42Christian Maeder sprintf(msg, "Safepoint sync time longer than " INTX_FORMAT "ms detected when executing %s.",

11a8f0b56c43688f967c4f592db6807d9f279f42Christian Maeder SafepointTimeoutDelay,

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder op != NULL ? op->name() : "no vm operation");

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder fatal(msg);

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder }

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder}

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian MaederThreadSafepointState::ThreadSafepointState(JavaThread *thread) {

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder _thread = thread;

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder _type = _running;

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder _has_called_back = false;

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder _at_poll_safepoint = false;

dd1f6a9c4c7860e85e5499dad5965e8cc4ae3814Christian Maeder}

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maedervoid ThreadSafepointState::create(JavaThread *thread) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder ThreadSafepointState *state = new ThreadSafepointState(thread);

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder thread->set_safepoint_state(state);

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder}

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maedervoid ThreadSafepointState::destroy(JavaThread *thread) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder if (thread->safepoint_state()) {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder delete(thread->safepoint_state());

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder thread->set_safepoint_state(NULL);

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder }

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder}

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maedervoid ThreadSafepointState::examine_state_of_thread() {

c26ff5708c4a855bf9503b3001bcc19e5fd6286fChristian Maeder assert(is_running(), "better be running or just have hit safepoint poll");

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder JavaThreadState state = _thread->thread_state();

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // Save the state at the start of safepoint processing.

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder _orig_thread_state = state;

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // Check for a thread that is suspended. Note that thread resume tries

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // to grab the Threads_lock which we own here, so a thread cannot be

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // resumed during safepoint synchronization.

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // We check to see if this thread is suspended without locking to

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // avoid deadlocking with a third thread that is waiting for this

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // thread to be suspended. The third thread can notice the safepoint

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // that we're trying to start at the beginning of its SR_lock->wait()

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // call. If that happens, then the third thread will block on the

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // safepoint while still holding the underlying SR_lock. We won't be

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // able to get the SR_lock and we'll deadlock.

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder //

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // We don't need to grab the SR_lock here for two reasons:

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // 1) The suspend flags are both volatile and are set with an

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // Atomic::cmpxchg() call so we should see the suspended

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // state right away.

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // 2) We're being called from the safepoint polling loop; if

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // we don't see the suspended state on this iteration, then

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // we'll come around again.

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder //

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder bool is_suspended = _thread->is_ext_suspended();

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder if (is_suspended) {

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder roll_forward(_at_safepoint);

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder return;

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder }

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // Some JavaThread states have an initial safepoint state of

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // running, but are actually at a safepoint. We will happily

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // agree and update the safepoint state here.

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder if (SafepointSynchronize::safepoint_safe(_thread, state)) {

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder roll_forward(_at_safepoint);

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder return;

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder }

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder if (state == _thread_in_vm) {

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder roll_forward(_call_back);

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder return;

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder }

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // All other thread states will continue to run until they

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // transition and self-block in state _blocked

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // Safepoint polling in compiled code causes the Java threads to do the same.

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder // Note: new threads may require a malloc so they must be allowed to finish

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder assert(is_running(), "examine_state_of_thread on non-running thread");

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder return;

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder}

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maedervoid ThreadSafepointState::roll_forward(suspend_type type) {

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder _type = type;

f76ecb66e7bc7b8b89384943f151465effc47942Christian Maeder

switch(_type) {

case _at_safepoint:

SafepointSynchronize::signal_thread_at_safepoint();

break;

case _call_back:

set_has_called_back(false);

break;

case _running:

default:

ShouldNotReachHere();

}

}

void ThreadSafepointState::restart() {

switch(type()) {

case _at_safepoint:

case _call_back:

break;

case _running:

default:

tty->print_cr("restart thread "INTPTR_FORMAT" with state %d",

_thread, _type);

_thread->print();

ShouldNotReachHere();

}

_type = _running;

set_has_called_back(false);

}

void ThreadSafepointState::print_on(outputStream *st) const {

const char *s;

switch(_type) {

case _running : s = "_running"; break;

case _at_safepoint : s = "_at_safepoint"; break;

case _call_back : s = "_call_back"; break;

default:

ShouldNotReachHere();

}

st->print_cr("Thread: " INTPTR_FORMAT

" [0x%2x] State: %s _has_called_back %d _at_poll_safepoint %d",

_thread, _thread->osthread()->thread_id(), s, _has_called_back,

_at_poll_safepoint);

_thread->print_thread_state_on(st);

}

void ThreadSafepointState::handle_polling_page_exception() {

// Check state. block() will set thread state to thread_in_vm which will

// cause the safepoint state _type to become _call_back.

assert(type() == ThreadSafepointState::_running,

"polling page exception on thread not running state");

// Step 1: Find the nmethod from the return address

if (ShowSafepointMsgs && Verbose) {

tty->print_cr("Polling page exception at " INTPTR_FORMAT, thread()->saved_exception_pc());

}

address real_return_addr = thread()->saved_exception_pc();

CodeBlob *cb = CodeCache::find_blob(real_return_addr);

assert(cb != NULL && cb->is_nmethod(), "return address should be in nmethod");

nmethod* nm = (nmethod*)cb;

// Find frame of caller

frame stub_fr = thread()->last_frame();

CodeBlob* stub_cb = stub_fr.cb();

assert(stub_cb->is_safepoint_stub(), "must be a safepoint stub");

RegisterMap map(thread(), true);

frame caller_fr = stub_fr.sender(&map);

// Should only be poll_return or poll

assert( nm->is_at_poll_or_poll_return(real_return_addr), "should not be at call" );

// This is a poll immediately before a return. The exception handling code

// has already had the effect of causing the return to occur, so the execution

// will continue immediately after the call. In addition, the oopmap at the

// return point does not mark the return value as an oop (if it is), so

// it needs a handle here to be updated.

if( nm->is_at_poll_return(real_return_addr) ) {

// See if return type is an oop.

bool return_oop = nm->method()->is_returning_oop();

Handle return_value;

if (return_oop) {

// The oop result has been saved on the stack together with all

// the other registers. In order to preserve it over GCs we need

// to keep it in a handle.

oop result = caller_fr.saved_oop_result(&map);

assert(result == NULL || result->is_oop(), "must be oop");

return_value = Handle(thread(), result);

assert(Universe::heap()->is_in_or_null(result), "must be heap pointer");

}

// Block the thread

SafepointSynchronize::block(thread());

// restore oop result, if any

if (return_oop) {

caller_fr.set_saved_oop_result(&map, return_value());

}

}

// This is a safepoint poll. Verify the return address and block.

else {

set_at_poll_safepoint(true);

// verify the blob built the "return address" correctly

assert(real_return_addr == caller_fr.pc(), "must match");

// Block the thread

SafepointSynchronize::block(thread());

set_at_poll_safepoint(false);

// If we have a pending async exception deoptimize the frame

// as otherwise we may never deliver it.

if (thread()->has_async_condition()) {

ThreadInVMfromJavaNoAsyncException __tiv(thread());

VM_DeoptimizeFrame deopt(thread(), caller_fr.id());

VMThread::execute(&deopt);

}

// If an exception has been installed we must check for a pending deoptimization

// Deoptimize frame if exception has been thrown.

if (thread()->has_pending_exception() ) {

RegisterMap map(thread(), true);

frame caller_fr = stub_fr.sender(&map);

if (caller_fr.is_deoptimized_frame()) {

// The exception patch will destroy registers that are still

// live and will be needed during deoptimization. Defer the

// Async exception should have defered the exception until the

// next safepoint which will be detected when we get into

// the interpreter so if we have an exception now things

// are messed up.

fatal("Exception installed and deoptimization is pending");

}

}

}

}

SafepointSynchronize::SafepointStats* SafepointSynchronize::_safepoint_stats = NULL;

jlong SafepointSynchronize::_safepoint_begin_time = 0;

int SafepointSynchronize::_cur_stat_index = 0;

julong SafepointSynchronize::_safepoint_reasons[VM_Operation::VMOp_Terminating];

julong SafepointSynchronize::_coalesced_vmop_count = 0;

jlong SafepointSynchronize::_max_sync_time = 0;

jlong SafepointSynchronize::_max_vmop_time = 0;

float SafepointSynchronize::_ts_of_current_safepoint = 0.0f;

static jlong cleanup_end_time = 0;

static bool need_to_track_page_armed_status = false;

static bool init_done = false;

static void print_header() {

tty->print(" vmop "

"[threads: total initially_running wait_to_block] ");

tty->print("[time: spin block sync cleanup vmop] ");

// no page armed status printed out if it is always armed.

if (need_to_track_page_armed_status) {

tty->print("page_armed ");

}

tty->print_cr("page_trap_count");

}

void SafepointSynchronize::deferred_initialize_stat() {

if (init_done) return;

if (PrintSafepointStatisticsCount <= 0) {

fatal("Wrong PrintSafepointStatisticsCount");

}

// If PrintSafepointStatisticsTimeout is specified, the statistics data will

// be printed right away, in which case, _safepoint_stats will regress to

// a single element array. Otherwise, it is a circular ring buffer with default

// size of PrintSafepointStatisticsCount.

int stats_array_size;

if (PrintSafepointStatisticsTimeout > 0) {

stats_array_size = 1;

PrintSafepointStatistics = true;

} else {

stats_array_size = PrintSafepointStatisticsCount;

}

_safepoint_stats = (SafepointStats*)os::malloc(stats_array_size

* sizeof(SafepointStats));

guarantee(_safepoint_stats != NULL,

"not enough memory for safepoint instrumentation data");

if (UseCompilerSafepoints && DeferPollingPageLoopCount >= 0) {

need_to_track_page_armed_status = true;

}

init_done = true;

}

void SafepointSynchronize::begin_statistics(int nof_threads, int nof_running) {

assert(init_done, "safepoint statistics array hasn't been initialized");

SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];

spstat->_time_stamp = _ts_of_current_safepoint;

VM_Operation *op = VMThread::vm_operation();

spstat->_vmop_type = (op != NULL ? op->type() : -1);

if (op != NULL) {

_safepoint_reasons[spstat->_vmop_type]++;

}

spstat->_nof_total_threads = nof_threads;

spstat->_nof_initial_running_threads = nof_running;

spstat->_nof_threads_hit_page_trap = 0;

// Records the start time of spinning. The real time spent on spinning

// will be adjusted when spin is done. Same trick is applied for time

// spent on waiting for threads to block.

if (nof_running != 0) {

spstat->_time_to_spin = os::javaTimeNanos();

} else {

spstat->_time_to_spin = 0;

}

}

void SafepointSynchronize::update_statistics_on_spin_end() {

SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];

jlong cur_time = os::javaTimeNanos();

spstat->_nof_threads_wait_to_block = _waiting_to_block;

if (spstat->_nof_initial_running_threads != 0) {

spstat->_time_to_spin = cur_time - spstat->_time_to_spin;

}

if (need_to_track_page_armed_status) {

spstat->_page_armed = (PageArmed == 1);

}

// Records the start time of waiting for to block. Updated when block is done.

if (_waiting_to_block != 0) {

spstat->_time_to_wait_to_block = cur_time;

} else {

spstat->_time_to_wait_to_block = 0;

}

}

void SafepointSynchronize::update_statistics_on_sync_end(jlong end_time) {

SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];

if (spstat->_nof_threads_wait_to_block != 0) {

spstat->_time_to_wait_to_block = end_time -

spstat->_time_to_wait_to_block;

}

// Records the end time of sync which will be used to calculate the total

// vm operation time. Again, the real time spending in syncing will be deducted

// from the start of the sync time later when end_statistics is called.

spstat->_time_to_sync = end_time - _safepoint_begin_time;

if (spstat->_time_to_sync > _max_sync_time) {

_max_sync_time = spstat->_time_to_sync;

}

spstat->_time_to_do_cleanups = end_time;

}

void SafepointSynchronize::update_statistics_on_cleanup_end(jlong end_time) {

SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];

// Record how long spent in cleanup tasks.

spstat->_time_to_do_cleanups = end_time - spstat->_time_to_do_cleanups;

cleanup_end_time = end_time;

}

void SafepointSynchronize::end_statistics(jlong vmop_end_time) {

SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];

// Update the vm operation time.

spstat->_time_to_exec_vmop = vmop_end_time - cleanup_end_time;

if (spstat->_time_to_exec_vmop > _max_vmop_time) {

_max_vmop_time = spstat->_time_to_exec_vmop;

}

// Only the sync time longer than the specified

// PrintSafepointStatisticsTimeout will be printed out right away.

// By default, it is -1 meaning all samples will be put into the list.

if ( PrintSafepointStatisticsTimeout > 0) {

if (spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) {

print_statistics();

}

} else {

// The safepoint statistics will be printed out when the _safepoin_stats

// array fills up.

if (_cur_stat_index == PrintSafepointStatisticsCount - 1) {

print_statistics();

_cur_stat_index = 0;

} else {

_cur_stat_index++;

}

}

}

void SafepointSynchronize::print_statistics() {

SafepointStats* sstats = _safepoint_stats;

for (int index = 0; index <= _cur_stat_index; index++) {

if (index % 30 == 0) {

print_header();

}

sstats = &_safepoint_stats[index];

tty->print("%.3f: ", sstats->_time_stamp);

tty->print("%-26s ["

INT32_FORMAT_W(8)INT32_FORMAT_W(11)INT32_FORMAT_W(15)

" ] ",

sstats->_vmop_type == -1 ? "no vm operation" :

VM_Operation::name(sstats->_vmop_type),

sstats->_nof_total_threads,

sstats->_nof_initial_running_threads,

sstats->_nof_threads_wait_to_block);

// "/ MICROUNITS " is to convert the unit from nanos to millis.

tty->print(" ["

INT64_FORMAT_W(6)INT64_FORMAT_W(6)

INT64_FORMAT_W(6)INT64_FORMAT_W(6)

INT64_FORMAT_W(6)" ] ",

sstats->_time_to_spin / MICROUNITS,

sstats->_time_to_wait_to_block / MICROUNITS,

sstats->_time_to_sync / MICROUNITS,

sstats->_time_to_do_cleanups / MICROUNITS,

sstats->_time_to_exec_vmop / MICROUNITS);

if (need_to_track_page_armed_status) {

tty->print(INT32_FORMAT" ", sstats->_page_armed);

}

tty->print_cr(INT32_FORMAT" ", sstats->_nof_threads_hit_page_trap);

}

}

void SafepointSynchronize::print_stat_on_exit() {

if (_safepoint_stats == NULL) return;

SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];

// During VM exit, end_statistics may not get called and in that

// case, if the sync time is less than PrintSafepointStatisticsTimeout,

// don't print it out.

// Approximate the vm op time.

_safepoint_stats[_cur_stat_index]._time_to_exec_vmop =

os::javaTimeNanos() - cleanup_end_time;

if ( PrintSafepointStatisticsTimeout < 0 ||

spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) {

print_statistics();

}

tty->print_cr("");

// Print out polling page sampling status.

if (!need_to_track_page_armed_status) {

if (UseCompilerSafepoints) {

tty->print_cr("Polling page always armed");

}

} else {

tty->print_cr("Defer polling page loop count = %d\n",

DeferPollingPageLoopCount);

}

for (int index = 0; index < VM_Operation::VMOp_Terminating; index++) {

if (_safepoint_reasons[index] != 0) {

tty->print_cr("%-26s"UINT64_FORMAT_W(10), VM_Operation::name(index),

_safepoint_reasons[index]);

}

}

tty->print_cr(UINT64_FORMAT_W(5)" VM operations coalesced during safepoint",

_coalesced_vmop_count);

tty->print_cr("Maximum sync time "INT64_FORMAT_W(5)" ms",

_max_sync_time / MICROUNITS);

tty->print_cr("Maximum vm operation time (except for Exit VM operation) "

INT64_FORMAT_W(5)" ms",

_max_vmop_time / MICROUNITS);

}

#ifndef PRODUCT

void SafepointSynchronize::print_state() {

if (_state == _not_synchronized) {

tty->print_cr("not synchronized");

} else if (_state == _synchronizing || _state == _synchronized) {

tty->print_cr("State: %s", (_state == _synchronizing) ? "synchronizing" :

"synchronized");

for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) {

cur->safepoint_state()->print();

}

}

}

void SafepointSynchronize::safepoint_msg(const char* format, ...) {

if (ShowSafepointMsgs) {

va_list ap;

va_start(ap, format);

tty->vprint_cr(format, ap);

va_end(ap);

}

}

#endif // !PRODUCT