[Cbe-oss-dev] [PATCH 3/3] spufs context switch - fix interrupt routing

[Benjamin Herrenschmidt]

On Wed, 2008-04-23 at 22:42 -0300, Luke Browning wrote:
> I assume back to back interrupts happen all the time.

Yes.

>   The difference in
> this case is that we are re-routing interrupts within a few hundred
> instructions of issuing the dma restart.

Yup.

>   I assume we context switched
> the spu context while it was segment faulting which caused the dma
> restart to be deferred to context restore code within a few instructions
> of the spu interrupt rerouting.  I assume that the SLB was not reloaded
> by the context switch code, so the two faults were regenerated.  

Depends, there are other scenario, but yeah, basically.

> > There should never be two hash misses unless there is a restart in
> > between.
> > 
> 
> Can you have a class 0 exception and a class 1 hash miss occur at the
> same time?  If so, we still have the same issue.

A different one (issue) as these are separate handlers altogether and
don't muck up with CSA fields etc...

But yes, it would be possible.

Ben.