Network card interrupt handling

[Adrian Chadd]

[snip]

Well, the other big reason for doing it deferred like this is to avoid
network based deadlocks because you're being fed packets faster than
you can handle them. If you never yield, you stop other NIC
processing.

People used to do run-to-completion and then complained when this
happened, so polling was a thing.

So - I'm all for doing it with a fast interrupt handler and a fast
taskqueue. As long as we don't run things to completion and
re-schedule the taskqueue (so other things on that core get network
processing) then I'm okay.

(I kinda want us to have NAPI at some point...)



-adrian