From: Edward Cree <ec...@solarflare.com> Date: Thu, 12 Apr 2018 15:02:50 +0100
> A misconfigured system (e.g. with all interrupts affinitised to all CPUs) > may produce a storm of ARFS steering events. With the existing sfc ARFS > implementation, that could create a backlog of workitems that grinds the > system to a halt. To prevent this, limit the number of workitems that > may be in flight for a given SFC device to 8 (EFX_RPS_MAX_IN_FLIGHT), and > return EBUSY from our ndo_rx_flow_steer method if the limit is reached. > Given this limit, also store the workitems in an array of slots within the > struct efx_nic, rather than dynamically allocating for each request. > > Signed-off-by: Edward Cree <ec...@solarflare.com> I don't think this behavior is all that great. If you really have to queue up these operations because they take a long time, I think it is better to enter a synchronous mode and sleep once you hit this in-flight limit of 8. Either that or make the expiration work smarter when it has lots of events to process.
