Re: [PATCH v1 1/1] wq: Avoid using isolated cpus' timers on unbounded queue_delayed_work

Tejun Heo
2024-01-29T18:18:17Z

Hello,

On Fri, Jan 26, 2024 at 07:05:35PM -0300, Leonardo Bras wrote:
> > if (housekeeping_enabled(HK_TYPE_TIMER)) {
> > cpu = smp_processor_id();
> > if (!housekeeping_test_cpu(cpu, HK_TYPE_TIMER))
> > cpu = housekeeping_any_cpu(HK_TYPE_TIMER);
> > add_timer_on(timer, cpu);
> > } else {
> > if (likely(cpu == WORK_CPU_UNBOUND))
> > add_timer(timer, cpu);
> > else
> > add_timer_on(timer, cpu);
> > }
> >
> > Thanks.
>
> I am not really against it, but for me it's kind of weird to have that many
> calls to add_timer_on() if we can avoid it.
>
> I would rather go with:
>
> ###
> if (unlikely(cpu != WORK_CPU_UNBOUND)) {
> add_timer_on(timer, cpu);
> return;
> }
>
> if (!housekeeping_enabled(HK_TYPE_TIMER)) {
> add_timer(timer);
> return;
> }
>
> cpu = smp_processor_id();
> if (!housekeeping_test_cpu(cpu, HK_TYPE_TIMER))
> cpu = housekeeping_any_cpu(HK_TYPE_TIMER);
>
> add_timer_on(timer, cpu);
> ###
>
> What do you think?

Isn't that still the same number of add_timer[_on]() calls?

Thanks.

--
tejun