[openib-general] [PATCH] IB/ipoib: NAPI

[Roland Dreier]

 > What were your thoughts on how to handle this part of Eli's proposed
 > code:
 > 	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
 > 	/* TODO we need peek_cq here for hw devices that
 > 	   could would not generate interrupts for completions
 > 	   arriving between end of polling till request notify */
 > 
 > 	return 0;
 > 
 > On a non-Mellanox HCA, if the CQ is not empty here, isn't this required
 > to poll it til empty and process all the CQEs (otherwise we may not get
 > another interrupt).  If instead we return 1 from the dev->poll routine
 > here, we could be scheduled for a future poll and a future interrupt
 > (which might be bad).

That's exactly where we need peek CQ.  We can't repoll the CQ, because
netif_rx_complete() has already been called, so the poll routine might
already be running on another CPU.  The only thing I can see to do is
peek in the CQ, and if it's not empty, then go through the whole
netif_rx_reschedule() song and dance.

 - R.