Re: [PATCH v2 2/6] genirq: Allow an interrupt to be marked as 'raw'

Peter Zijlstra
2020-12-03T13:04:12Z

On Thu, Nov 26, 2020 at 06:18:33PM +0000, Valentin Schneider wrote:
> If I got the RCU bits right from what Thomas mentioned in
>
> https://lore.kernel.org/r/87ft5q18qs.fsf@nanos.tec.linutronix.de
> https://lore.kernel.org/r/87lfewnmdz.fsf@nanos.tec.linutronix.de
>
> then we're still missing something to notify RCU in the case the IRQ hits
> the idle task. All I see on our entry path is
>
> trace_hardirqs_off();
> ...
> irq_handler()
> handle_domain_irq();
> ...
> trace_hardirqs_on();
>
> so we do currently rely on handle_domain_irq()'s irq_enter() + irq_exit()
> for that. rcu_irq_enter() says CONFIG_RCU_EQS_DEBUG=y can detect missing
> bits, but I don't get any warnings with your series on my Juno.

The scheduler IPI really doesn't need RCU either ;-)