Re: [PATCH v4] genirq: add support for warning on long-running IRQ handlers

[Jiri Slaby]

On 24. 07. 25, 17:50, Wladislav Wiebe wrote:
> Introduce a mechanism to detect and warn about prolonged IRQ handlers.
> With a new command-line parameter (irqhandler.duration_warn_us=),
> users can configure the duration threshold in microseconds when a warning
> in such format should be emitted:
>
> "[CPU14] long duration of IRQ[159:bad_irq_handler [long_irq]], took: 1330 us"
>
> The implementation uses local_clock() to measure the execution duration of the
> generic IRQ per-CPU event handler.


This version LGTM

Reviewed-by: Jiri Slaby <jirislaby@xxxxxxxxxx>

> --- a/kernel/irq/handle.c
> +++ b/kernel/irq/handle.c
...
> +static inline void irqhandler_duration_check(u64 ts_start, unsigned int irq,
> +					     const struct irqaction *action)
> +{
> +	u64 delta_ns = local_clock() - ts_start;
> +
> +	if (unlikely(delta_ns > irqhandler_duration_threshold_ns)) {
> +		pr_warn_ratelimited("[CPU%u] long duration of IRQ[%u:%ps], took: %llu us\n",
> +				    smp_processor_id(), irq, action->handler,
> +				    delta_ns >> 10);

Only that: would the division matter in here? Or print ns? But feel free 
to ignore this.

thanks,
--
js
suse labs