Tasklet usage?

[Pierre Ossman <drzeus-list@drzeus.cx>]

My driver needs to spend a lot of time inside the interrupt handler 
(draining a FIFO). I suspect this might cause problems blocking other 
interrupt handlers so I was thinking about moving this into a tasklet.
Not being to familiar with tasklets, a few questions pop up.

* Will a tasklet scheduled from the interrupt handler be executed as 
soon as interrupt handling is done?
* Can tasklets be preempted?
* If a tasklet gets scheduled while running, will it be executed once 
more? (Needed if I get another FIFO interrupt while the tasklet is just 
exiting).

The FIFO is a bit small so time is of the essence. That's why this 
routine is in the interrupt handler to begin with.

Rgds
Pierre Ossman