Re: [PATCH net-next 16/16] sfc: Don't receive packets when the napi budget == 0

Eric Dumazet [off-list ref] writes:

On Sat, 2014-03-15 at 17:23 +0000, Ben Hutchings wrote:

quoted

The Solarflare hardware provides generic event queues for RX and TX
completions, link changes, errors, etc.  The driver can't process TX
completions without going through all the other events mixed in with
them.

ndo_poll_controller() could process all events, and queue incoming
packets through netif_rx().

Nobody cares about performance in this path.

I made this change so that we don't process rx packets in hard irq
context and cause things to break, and I made the most minimal most
obvious change I could.

queueing incoming packets with trough netif_rx sounds elegant.

The practical challenge is that there might be napi bottom halves
already scheduled to run before ndo_poll_controller is called so even
if ndo_poll_controller processes all of the events and calls netif_rx
to deal with the incoming packets the napi bottom halves will have to
still not process the queues when they are called.

Eric