Re: [PATCHv9 2/3] irq: use a struct for the kstat_irqs in the interrupt descriptor

Thomas Gleixner
2024-02-23T07:29:39Z

On Fri, Feb 23 2024 at 15:18, Bitao Hu wrote:
> On 2024/2/22 21:22, Thomas Gleixner wrote:
>>> - if (desc->kstat_irqs) {
>>> - for_each_online_cpu(j)
>>> - any_count |= data_race(*per_cpu_ptr(desc->kstat_irqs, j));
>>> - }
>>> + if (desc->kstat_irqs)
>>> + any_count = data_race(desc->tot_count);
>>
>> This is an unrelated change and needs to be split out into a separate
>> patch with a proper changelog which explains why this is equivalent.
>>
>
> Alright, I will remove this change witch is not related to the purpose
> of this patch.
>
> I guess that the purpose of suggesting this change in your V1 response
> was to speedup the 'show_interrupts'. However, after reviewing the
> usage of 'desc->tot_count' in 'unsigned int kstat_irqs(unsigned int
> irq)', I think the change might be as follows:
>
> diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
> index 623b8136e9af..53b8d6edd7ac 100644
> --- a/kernel/irq/proc.c
> +++ b/kernel/irq/proc.c
> @@ -489,8 +489,13 @@ int show_interrupts(struct seq_file *p, void *v)
> goto outsparse;
>
> if (desc->kstat_irqs) {
> - for_each_online_cpu(j)
> - any_count |=
> data_race(per_cpu(desc->kstat_irqs->cnt, j));
> + if (!irq_settings_is_per_cpu_devid(desc) &&
> + !irq_settings_is_per_cpu(desc) &&
> + !irq_is_nmi(desc))
> + any_count = data_race(desc->tot_count);
> + else
> + for_each_online_cpu(j)
> + any_count |=
> data_race(per_cpu(desc->kstat_irqs->cnt, j));
> }
>
> if ((!desc->action || irq_desc_is_chained(desc)) && !any_count)
>
> Is my idea correct?

Yes.