src/hotspot/share/prims/unsafe.cpp

rev 47287 : Port 09.17.Thread_SMR_logging_update from JDK9 to JDK10
rev 47288 : sspitsyn, dcubed, eosterlund CR - minor changes prior to OpenJDK review.
rev 47289 : eosterlund, stefank CR - refactor code into threadSMR.cpp and threadSMR.hpp

*** 36,45 ****
--- 36,47 ----
  #include "runtime/atomic.hpp"
  #include "runtime/globals.hpp"
  #include "runtime/interfaceSupport.hpp"
  #include "runtime/orderAccess.inline.hpp"
  #include "runtime/reflection.hpp"
+ #include "runtime/thread.hpp"
+ #include "runtime/threadSMR.hpp"
  #include "runtime/vm_version.hpp"
  #include "services/threadService.hpp"
  #include "trace/tracing.hpp"
  #include "utilities/align.hpp"
  #include "utilities/copy.hpp"
*** 1102,1136 ****
  
  UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
    Parker* p = NULL;
  
    if (jthread != NULL) {
!     oop java_thread = JNIHandles::resolve_non_null(jthread);
      if (java_thread != NULL) {
        jlong lp = java_lang_Thread::park_event(java_thread);
        if (lp != 0) {
          // This cast is OK even though the jlong might have been read
          // non-atomically on 32bit systems, since there, one word will
          // always be zero anyway and the value set is always the same
          p = (Parker*)addr_from_java(lp);
        } else {
!         // Grab lock if apparently null or using older version of library
!         MutexLocker mu(Threads_lock);
!         java_thread = JNIHandles::resolve_non_null(jthread);
! 
!         if (java_thread != NULL) {
!           JavaThread* thr = java_lang_Thread::thread(java_thread);
            if (thr != NULL) {
              p = thr->parker();
!             if (p != NULL) { // Bind to Java thread for next time.
                java_lang_Thread::set_park_event(java_thread, addr_to_java(p));
              }
            }
          }
        }
!     }
!   }
  
    if (p != NULL) {
      HOTSPOT_THREAD_UNPARK((uintptr_t) p);
      p->unpark();
    }
--- 1104,1139 ----
  
  UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
    Parker* p = NULL;
  
    if (jthread != NULL) {
!     ThreadsListHandle tlh;
!     JavaThread* thr = NULL;
!     oop java_thread = NULL;
!     (void) tlh.cv_internal_thread_to_JavaThread(jthread, &thr, &java_thread);
      if (java_thread != NULL) {
+       // This is a valid oop.
        jlong lp = java_lang_Thread::park_event(java_thread);
        if (lp != 0) {
          // This cast is OK even though the jlong might have been read
          // non-atomically on 32bit systems, since there, one word will
          // always be zero anyway and the value set is always the same
          p = (Parker*)addr_from_java(lp);
        } else {
!         // Not cached in the java.lang.Thread oop yet (could be an
!         // older version of library).
          if (thr != NULL) {
+           // The JavaThread is alive.
            p = thr->parker();
!           if (p != NULL) {
!             // Cache the Parker in the java.lang.Thread oop for next time.
              java_lang_Thread::set_park_event(java_thread, addr_to_java(p));
            }
          }
        }
      }
!   } // ThreadsListHandle is destroyed here.
  
    if (p != NULL) {
      HOTSPOT_THREAD_UNPARK((uintptr_t) p);
      p->unpark();
    }