Re: [RT] Question about i40e threaded irq

[Thomas Gleixner]

On Tue, May 11 2021 at 08:09, Juri Lelli wrote:
> My understanding is that rps_trigger_softirq() sneaked in while
> i40e_msix_clean_rings() threaded irq was running and, since the latter is
> using napi_schedule_irqoff(), the softnet_data poll_list got eventually
> corrupted.
>
> Now, doing s/napi_schedule_irqoff/napi_schedule/ in the i40e driver seem
> to cure the problem. I'm not sure that there isn't a more general
> solution, though. Is it expected that napi_schedule_irqoff users in RT
> know what they are doing or do we want/need to fix this in a more
> general way?

The straight forward fix it to map napi_schedule_irqoff() to
napi_schedule() on RT. Fixing this at the driver level is a whack-a-mole
game.

Thanks,

        tglx