TASK CONTROL INFORMATION SCALABILITY

```
Description: Task control information is retained in simple lists. This
is completely appropriate for small embedded systems where
the number of tasks, N, is relatively small. Most list
operations are O(N). This could become an issue if N gets
very large.

In that case, these simple lists should be replaced with
something more performant such as a balanced tree in the
case of ordered lists. Fortunately, most internal lists are
hidden behind simple accessor functions and so the internal
data structures can be changed if need with very little impact.

Explicitly reference to the list structure are hidden behind
the macro this_task().

Status: Open
Priority: Low. Things are just the way that we want them for the way
that NuttX is used today.
```