Exemple #1
0
 /**
  * Complete the task of acquiring the heavy lock, assuming that the mutex is already acquired
  * (locked).
  */
 @Unpreemptible
 public boolean lockHeavyLocked(Object o) {
   if (lockedObject != o) { // lock disappeared before we got here
     mutex.unlock(); // thread switching benign
     return false;
   }
   if (STATS) lockOperations++;
   RVMThread me = RVMThread.getCurrentThread();
   int threadId = me.getLockingId();
   if (ownerId == threadId) {
     recursionCount++;
   } else if (ownerId == 0) {
     ownerId = threadId;
     recursionCount = 1;
   } else {
     entering.enqueue(me);
     mutex.unlock();
     me.monitor().lockNoHandshake();
     while (entering.isQueued(me)) {
       me.monitor().waitWithHandshake(); // this may spuriously return
     }
     me.monitor().unlock();
     return false;
   }
   mutex.unlock(); // thread-switching benign
   return true;
 }
Exemple #2
0
 /**
  * Releases this heavy-weight lock on the indicated object.
  *
  * @param o the object to be unlocked
  */
 @Unpreemptible
 public void unlockHeavy(Object o) {
   boolean deflated = false;
   mutex.lock(); // Note: thread switching is not allowed while mutex is held.
   RVMThread me = RVMThread.getCurrentThread();
   if (ownerId != me.getLockingId()) {
     mutex.unlock(); // thread-switching benign
     raiseIllegalMonitorStateException("heavy unlocking", o);
   }
   recursionCount--;
   if (0 < recursionCount) {
     mutex.unlock(); // thread-switching benign
     return;
   }
   if (STATS) unlockOperations++;
   ownerId = 0;
   RVMThread toAwaken = entering.dequeue();
   if (toAwaken == null && entering.isEmpty() && waiting.isEmpty()) { // heavy lock can be deflated
     // Possible project: decide on a heuristic to control when lock should be deflated
     Offset lockOffset = Magic.getObjectType(o).getThinLockOffset();
     if (!lockOffset.isMax()) { // deflate heavy lock
       deflate(o, lockOffset);
       deflated = true;
     }
   }
   mutex.unlock(); // does a Magic.sync();  (thread-switching benign)
   if (toAwaken != null) {
     toAwaken.monitor().lockedBroadcastNoHandshake();
   }
 }