Swapped out procs not brought in immediately after child exits

[David Xu]

Sam Lawrance wrote:

>>How-To-Repeat:
>>    
>>
>
>Run a shell somewhere (first). Su or run another shell or similar (second).
>Wait until the first shell has swapped out (might require running some other
>memory hogs). Exit the second shell. Notice that the second shell takes a
>long time to exit.
>
>  
>
This reminds me that it is another swappable kernel stack problem, if we 
don't have
it, we even needn't TDP_WAKEPROC0  hack, interesting. :)

David Xu