Re: [PATCH] genirq: reduce irqdebug bouncing cachelines

From: Cédric Le Goater
Date: Tue Apr 13 2021 - 08:17:01 EST


Thomas,

>> We could test irq_settings_no_debug() directly under handle_nested_irq()
>> and handle_irq_event_percpu() to avoid calling note_interrupt(), just
>> like we do for noirqdebug.
>
> We can do that, but then we should not just make it:
>
> if (!irqnodebug && !irq_settings_no_debug(desc))
> note_interrupt(...);
>
> Instead have only one condition:
>
> if (!irq_settings_no_debug(desc))
> note_interrupt(...);
>
> See the uncompiled delta patch below.

I merged this second part with the first and gave IRQF_NO_DEBUG a try
on P8 and P9 systems and all looked fine. I should send both patches
after IRQF_NO_AUTOEN is merged in mainline.

Thanks,

C.