[ofa-general] Questions about IPOIB handle last WQE event

[Shirley Ma]

On Fri, 2008-07-25 at 10:25 -0700, Roland Dreier wrote:
> The current code at least tries to do this: it decrements the recv_count
> on every receive completion with unsuccessful status, and moves an rx
> countext to the reap list when its last receive completes.  I don't see
> any obvious bug here; is it not working in your tests?

Right, it doesn't work.

>  > To use post_send last WR is much simple, just wait for this CQE to be
>  > generated in CQ then release the resource. The wait time here might be
>  > much smaller than above approach.
> 
> But when do you post the send work request?  This only works if you
> already know the last receive has completed, because there is no
> synchronization required between the receive queue and the send queue,
> and so the completion of the send work request doesn't tell you anything
> you didn't already know.
> 
>  - R.

Do the post send work request whenever receiving DREQ, which meant the
remote TX QP has already teared down, there is no new post recv
completions any more after DREQ.

Thanks
Shirley