/**
* Promotes a light-weight lock to a heavy-weight lock and locks it. Note: the object in question
* will normally be locked by another thread, or it may be unlocked. If there is already a
* heavy-weight lock on this object, that lock is returned.
*
* @param o the object to get a heavy-weight lock
* @param lockOffset the offset of the thin lock word in the object.
* @return whether the object was successfully locked
*/
@Unpreemptible
private static boolean inflateAndLock(Object o, Offset lockOffset) {
Lock l = Lock.allocate();
if (l == null) return false; // can't allocate locks during GC
Lock rtn = attemptToInflate(o, lockOffset, l);
if (l != rtn) {
l = rtn;
l.mutex.lock();
}
return l.lockHeavyLocked(o);
}
/**
* Promotes a light-weight lock to a heavy-weight lock. Note: the object is question will normally
* be locked by another thread, or it may be unlocked. If there is already a heavy-weight lock on
* this object, that lock is returned.
*
* @param o the object to get a heavy-weight lock
* @param lockOffset the offset of the thin lock word in the object.
* @return the heavy-weight lock on this object
*/
@Unpreemptible
private static Lock inflate(Object o, Offset lockOffset) {
Lock l = Lock.allocate();
if (VM.VerifyAssertions) {
VM._assert(
l != null); // inflate called by wait (or notify) which shouldn't be called during GC
}
Lock rtn = attemptToInflate(o, lockOffset, l);
if (rtn == l) l.mutex.unlock();
return rtn;
}