Beispiel #1
0
void VM_ThreadDump::doit() {
  ResourceMark rm;

  ConcurrentLocksDump concurrent_locks(true);
  if (_with_locked_synchronizers) {
    concurrent_locks.dump_at_safepoint();
  }

  if (_num_threads == 0) {
    // Snapshot all live threads
    for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
      if (jt->is_exiting() ||
          jt->is_hidden_from_external_view())  {
        // skip terminating threads and hidden threads
        continue;
      }
      ThreadConcurrentLocks* tcl = NULL;
      if (_with_locked_synchronizers) {
        tcl = concurrent_locks.thread_concurrent_locks(jt);
      }
      ThreadSnapshot* ts = snapshot_thread(jt, tcl);
      _result->add_thread_snapshot(ts);
    }
  } else {
    // Snapshot threads in the given _threads array
    // A dummy snapshot is created if a thread doesn't exist
    for (int i = 0; i < _num_threads; i++) {
      instanceHandle th = _threads->at(i);
      if (th() == NULL) {
        // skip if the thread doesn't exist
        // Add a dummy snapshot
        _result->add_thread_snapshot(new ThreadSnapshot());
        continue;
      }

      // Dump thread stack only if the thread is alive and not exiting
      // and not VM internal thread.
      JavaThread* jt = java_lang_Thread::thread(th());
      if (jt == NULL || /* thread not alive */
          jt->is_exiting() ||
          jt->is_hidden_from_external_view())  {
        // add a NULL snapshot if skipped
        _result->add_thread_snapshot(new ThreadSnapshot());
        continue;
      }
      ThreadConcurrentLocks* tcl = NULL;
      if (_with_locked_synchronizers) {
        tcl = concurrent_locks.thread_concurrent_locks(jt);
      }
      ThreadSnapshot* ts = snapshot_thread(jt, tcl);
      _result->add_thread_snapshot(ts);
    }
  }
}
 void doit() {
   ResourceMark rmark; // _thread != Thread::current()
   RegisterMap rm(_thread, false);
   // There can be a race condition between a VM_Operation reaching a safepoint
   // and the target thread exiting from Java execution.
   // We must recheck the last Java frame still exists.
   if (!_thread->is_exiting() && _thread->has_last_Java_frame()) {
     javaVFrame* vf = _thread->last_java_vframe(&rm);
     assert(vf != NULL, "must have last java frame");
     Method* method = vf->method();
     _method_id = method->jmethod_id();
     _bci = vf->bci();
   } else {
     // Clear current location as the target thread has no Java frames anymore.
     _method_id = (jmethodID)NULL;
     _bci = 0;
   }
 }
void FlatProfiler::record_thread_ticks() {

  int maxthreads, suspendedthreadcount;
  JavaThread** threadsList;
  bool interval_expired = false;

  if (ProfileIntervals &&
      (FlatProfiler::received_ticks >= interval_ticks_previous + ProfileIntervalsTicks)) {
    interval_expired = true;
    interval_ticks_previous = FlatProfiler::received_ticks;
  }

  // Try not to wait for the Threads_lock
  if (Threads_lock->try_lock()) {
    {  // Threads_lock scope
      maxthreads = Threads::number_of_threads();
      threadsList = NEW_C_HEAP_ARRAY(JavaThread *, maxthreads, mtInternal);
      suspendedthreadcount = 0;
      for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) {
        if (tp->is_Compiler_thread()) {
          // Only record ticks for active compiler threads
          CompilerThread* cthread = (CompilerThread*)tp;
          if (cthread->task() != NULL) {
            // The compiler is active.  If we need to access any of the fields
            // of the compiler task we should suspend the CompilerThread first.
            FlatProfiler::compiler_ticks += 1;
            continue;
          }
        }

        // First externally suspend all threads by marking each for
        // external suspension - so it will stop at its next transition
        // Then do a safepoint
        ThreadProfiler* pp = tp->get_thread_profiler();
        if (pp != NULL && pp->engaged) {
          MutexLockerEx ml(tp->SR_lock(), Mutex::_no_safepoint_check_flag);
          if (!tp->is_external_suspend() && !tp->is_exiting()) {
            tp->set_external_suspend();
            threadsList[suspendedthreadcount++] = tp;
          }
        }
      }
      Threads_lock->unlock();
    }
Beispiel #4
0
ThreadsListEnumerator::ThreadsListEnumerator(Thread* cur_thread,
                                             bool include_jvmti_agent_threads,
                                             bool include_jni_attaching_threads) {
  assert(cur_thread == Thread::current(), "Check current thread");

  int init_size = ThreadService::get_live_thread_count();
  _threads_array = new GrowableArray<instanceHandle>(init_size);

  MutexLockerEx ml(Threads_lock);

  for (JavaThread* jt = Threads::first(); jt != NULL; jt = jt->next()) {
    // skips JavaThreads in the process of exiting
    // and also skips VM internal JavaThreads
    // Threads in _thread_new or _thread_new_trans state are included.
    // i.e. threads have been started but not yet running.
    if (jt->threadObj() == NULL   ||
        jt->is_exiting() ||
        !java_lang_Thread::is_alive(jt->threadObj())   ||
        jt->is_hidden_from_external_view()) {
      continue;
    }

    // skip agent threads
    if (!include_jvmti_agent_threads && jt->is_jvmti_agent_thread()) {
      continue;
    }

    // skip jni threads in the process of attaching
    if (!include_jni_attaching_threads && jt->is_attaching_via_jni()) {
      continue;
    }

    instanceHandle h(cur_thread, (instanceOop) jt->threadObj());
    _threads_array->append(h);
  }
}
Beispiel #5
0
void AsyncGetCallTrace(ASGCT_CallTrace *trace, jint depth, void* ucontext) {

// This is if'd out because we no longer use thread suspension.
// However if someone wanted to backport this to a 5.0 jvm then this
// code would be important.
#if 0
  if (SafepointSynchronize::is_synchronizing()) {
    // The safepoint mechanism is trying to synchronize all the threads.
    // Since this can involve thread suspension, it is not safe for us
    // to be here. We can reduce the deadlock risk window by quickly
    // returning to the SIGPROF handler. However, it is still possible
    // for VMThread to catch us here or in the SIGPROF handler. If we
    // are suspended while holding a resource and another thread blocks
    // on that resource in the SIGPROF handler, then we will have a
    // three-thread deadlock (VMThread, this thread, the other thread).
    trace->num_frames = ticks_safepoint; // -10
    return;
  }
#endif

  JavaThread* thread;

  if (trace->env_id == NULL ||
    (thread = JavaThread::thread_from_jni_environment(trace->env_id)) == NULL ||
    thread->is_exiting()) {

    // bad env_id, thread has exited or thread is exiting
    trace->num_frames = ticks_thread_exit; // -8
    return;
  }

  if (thread->in_deopt_handler()) {
    // thread is in the deoptimization handler so return no frames
    trace->num_frames = ticks_deopt; // -9
    return;
  }

  assert(JavaThread::current() == thread,
         "AsyncGetCallTrace must be called by the current interrupted thread");

  if (!JvmtiExport::should_post_class_load()) {
    trace->num_frames = ticks_no_class_load; // -1
    return;
  }

  if (Universe::heap()->is_gc_active()) {
    trace->num_frames = ticks_GC_active; // -2
    return;
  }

  switch (thread->thread_state()) {
  case _thread_new:
  case _thread_uninitialized:
  case _thread_new_trans:
    // We found the thread on the threads list above, but it is too
    // young to be useful so return that there are no Java frames.
    trace->num_frames = 0;
    break;
  case _thread_in_native:
  case _thread_in_native_trans:
  case _thread_blocked:
  case _thread_blocked_trans:
  case _thread_in_vm:
  case _thread_in_vm_trans:
    {
      frame fr;

      // param isInJava == false - indicate we aren't in Java code
      if (!thread->pd_get_top_frame_for_signal_handler(&fr, ucontext, false)) {
        trace->num_frames = ticks_unknown_not_Java;  // -3 unknown frame
      } else {
        if (!thread->has_last_Java_frame()) {
          trace->num_frames = 0; // No Java frames
        } else {
          trace->num_frames = ticks_not_walkable_not_Java;    // -4 non walkable frame by default
          forte_fill_call_trace_given_top(thread, trace, depth, fr);

          // This assert would seem to be valid but it is not.
          // It would be valid if we weren't possibly racing a gc
          // thread. A gc thread can make a valid interpreted frame
          // look invalid. It's a small window but it does happen.
          // The assert is left here commented out as a reminder.
          // assert(trace->num_frames != ticks_not_walkable_not_Java, "should always be walkable");

        }
      }
    }
    break;
  case _thread_in_Java:
  case _thread_in_Java_trans:
    {
      frame fr;

      // param isInJava == true - indicate we are in Java code
      if (!thread->pd_get_top_frame_for_signal_handler(&fr, ucontext, true)) {
        trace->num_frames = ticks_unknown_Java;  // -5 unknown frame
      } else {
        trace->num_frames = ticks_not_walkable_Java;  // -6, non walkable frame by default
        forte_fill_call_trace_given_top(thread, trace, depth, fr);
      }
    }
    break;
  default:
    // Unknown thread state
    trace->num_frames = ticks_unknown_state; // -7
    break;
  }
}
Beispiel #6
0
JNIEXPORT
void AsyncGetCallTrace(ASGCT_CallTrace *trace, jint depth, void* ucontext) {
  JavaThread* thread;

  if (trace->env_id == NULL ||
    (thread = JavaThread::thread_from_jni_environment(trace->env_id)) == NULL ||
    thread->is_exiting()) {

    // bad env_id, thread has exited or thread is exiting
    trace->num_frames = ticks_thread_exit; // -8
    return;
  }

  if (thread->in_deopt_handler()) {
    // thread is in the deoptimization handler so return no frames
    trace->num_frames = ticks_deopt; // -9
    return;
  }

  assert(JavaThread::current() == thread,
         "AsyncGetCallTrace must be called by the current interrupted thread");

  if (!JvmtiExport::should_post_class_load()) {
    trace->num_frames = ticks_no_class_load; // -1
    return;
  }

  if (Universe::heap()->is_gc_active()) {
    trace->num_frames = ticks_GC_active; // -2
    return;
  }

  switch (thread->thread_state()) {
  case _thread_new:
  case _thread_uninitialized:
  case _thread_new_trans:
    // We found the thread on the threads list above, but it is too
    // young to be useful so return that there are no Java frames.
    trace->num_frames = 0;
    break;
  case _thread_in_native:
  case _thread_in_native_trans:
  case _thread_blocked:
  case _thread_blocked_trans:
  case _thread_in_vm:
  case _thread_in_vm_trans:
    {
      frame fr;

      // param isInJava == false - indicate we aren't in Java code
      if (!thread->pd_get_top_frame_for_signal_handler(&fr, ucontext, false)) {
        trace->num_frames = ticks_unknown_not_Java;  // -3 unknown frame
      } else {
        if (!thread->has_last_Java_frame()) {
          trace->num_frames = 0; // No Java frames
        } else {
          trace->num_frames = ticks_not_walkable_not_Java;    // -4 non walkable frame by default
          forte_fill_call_trace_given_top(thread, trace, depth, fr);

          // This assert would seem to be valid but it is not.
          // It would be valid if we weren't possibly racing a gc
          // thread. A gc thread can make a valid interpreted frame
          // look invalid. It's a small window but it does happen.
          // The assert is left here commented out as a reminder.
          // assert(trace->num_frames != ticks_not_walkable_not_Java, "should always be walkable");

        }
      }
    }
    break;
  case _thread_in_Java:
  case _thread_in_Java_trans:
    {
      frame fr;

      // param isInJava == true - indicate we are in Java code
      if (!thread->pd_get_top_frame_for_signal_handler(&fr, ucontext, true)) {
        trace->num_frames = ticks_unknown_Java;  // -5 unknown frame
      } else {
        trace->num_frames = ticks_not_walkable_Java;  // -6, non walkable frame by default
        forte_fill_call_trace_given_top(thread, trace, depth, fr);
      }
    }
    break;
  default:
    // Unknown thread state
    trace->num_frames = ticks_unknown_state; // -7
    break;
  }
}