On Wed, 2 Feb 2022 13:28:48 +0100 Sebastian Andrzej Siewior wrote:
> /* Schedule NAPI for backlog device
> * We can use non atomic operation since we own the queue lock
> + * PREEMPT_RT needs to disable interrupts here for
> + * synchronisation needed in napi_schedule.
> */
> + if (IS_ENABLED(CONFIG_PREEMPT_RT))
> + local_irq_disable();
> +
> if (!__test_and_set_bit(NAPI_STATE_SCHED, &sd->backlog.state)) {
> if (!rps_ipi_queued(sd))
> ____napi_schedule(sd, &sd->backlog);
> }
> + if (IS_ENABLED(CONFIG_PREEMPT_RT))
> + local_irq_enable();
> goto enqueue;
I think you can re-jig this a little more - rps_ipi_queued() only return
0 if sd is "local" so maybe we can call __napi_schedule_irqoff()
instead which already has the if () for PREEMPT_RT?
Maybe moving the ____napi_schedule() into rps_ipi_queued() and
renaming it to napi_schedule_backlog() or napi_schedule_rps()
would make the code easier to follow in that case?
