src/hotspot/share/runtime/interfaceSupport.hpp

rev 47413 : Introduce SafepointMechanism
rev 47415 : Add Thread Local handshakes and thread local polling

*** 185,195 ****
      InterfaceSupport::serialize_thread_state_with_handler(thread);
  
      // We never install asynchronous exceptions when coming (back) in
      // to the runtime from native code because the runtime is not set
      // up to handle exceptions floating around at arbitrary points.
!     if (SafepointMechanism::poll() || thread->is_suspend_after_native()) {
        JavaThread::check_safepoint_and_suspend_for_native_trans(thread);
  
        // Clear unhandled oops anywhere where we could block, even if we don't.
        CHECK_UNHANDLED_OOPS_ONLY(thread->clear_unhandled_oops();)
      }
--- 185,195 ----
      InterfaceSupport::serialize_thread_state_with_handler(thread);
  
      // We never install asynchronous exceptions when coming (back) in
      // to the runtime from native code because the runtime is not set
      // up to handle exceptions floating around at arbitrary points.
!     if (SafepointMechanism::poll(thread) || thread->is_suspend_after_native()) {
        JavaThread::check_safepoint_and_suspend_for_native_trans(thread);
  
        // Clear unhandled oops anywhere where we could block, even if we don't.
        CHECK_UNHANDLED_OOPS_ONLY(thread->clear_unhandled_oops();)
      }
*** 201,210 ****
--- 201,242 ----
     void trans_from_java(JavaThreadState to)              { transition_from_java(_thread, to); }
     void trans_from_native(JavaThreadState to)            { transition_from_native(_thread, to); }
     void trans_and_fence(JavaThreadState from, JavaThreadState to) { transition_and_fence(_thread, from, to); }
  };
  
+ class ThreadInVMForHandshake : public ThreadStateTransition {
+   const JavaThreadState _original_state;
+ 
+   void transition_back() {
+     // This can be invoked from transition states and must return to the original state properly
+     assert(_thread->thread_state() == _thread_in_vm, "should only call when leaving VM after handshake");
+     _thread->set_thread_state(_thread_in_vm_trans);
+ 
+     InterfaceSupport::serialize_thread_state(_thread);
+ 
+     SafepointMechanism::block_if_requested(_thread);
+ 
+     _thread->set_thread_state(_original_state);
+   }
+ 
+  public:
+ 
+   ThreadInVMForHandshake(JavaThread* thread) : ThreadStateTransition(thread),
+       _original_state(thread->thread_state()) {
+ 
+     if (thread->has_last_Java_frame()) {
+       thread->frame_anchor()->make_walkable(thread);
+     }
+ 
+     thread->set_thread_state(_thread_in_vm);
+   }
+ 
+   ~ThreadInVMForHandshake() {
+     transition_back();
+   }
+ 
+ };
  
  class ThreadInVMfromJava : public ThreadStateTransition {
   public:
    ThreadInVMfromJava(JavaThread* thread) : ThreadStateTransition(thread) {
      trans_from_java(_thread_in_vm);