On Wed, 9 Aug 2017, Vikas Shivappa wrote:

> @@ -426,6 +426,9 @@ static int domain_setup_mon_state(struct rdt_resource *r, 
> struct rdt_domain *d)
>                                          GFP_KERNEL);
>               if (!d->rmid_busy_llc)
>                       return -ENOMEM;
> +             INIT_DELAYED_WORK(&d->cqm_limbo, cqm_handle_limbo);
> +             if (has_busy_rmid(r, d))
> +                     cqm_setup_limbo_handler(d);

This is beyond silly. d->rmid_busy_llc is allocated a few lines above. How
would a bit be set here?

>       }
>       if (is_mbm_total_enabled()) {
>               tsize = sizeof(*d->mbm_total);
> @@ -536,11 +539,25 @@ static void domain_remove_cpu(int cpu, struct 
> rdt_resource *r)
>               list_del(&d->list);
>               if (is_mbm_enabled())
>                       cancel_delayed_work(&d->mbm_over);
> +
> +             if (is_llc_occupancy_enabled() &&
> +                 has_busy_rmid(r, d))

What is that line break helping here and why can't you just unconditionally
cancel the work?

> +                     cancel_delayed_work(&d->cqm_limbo);
> +
>               kfree(d);
> -     } else if (r == &rdt_resources_all[RDT_RESOURCE_L3] &&
> -                cpu == d->mbm_work_cpu && is_mbm_enabled()) {
> -             cancel_delayed_work(&d->mbm_over);
> -             mbm_setup_overflow_handler(d);
> +             return;
> +     }
> +
> +     if (r == &rdt_resources_all[RDT_RESOURCE_L3]) {
> +             if (is_mbm_enabled() && cpu == d->mbm_work_cpu) {
> +                     cancel_delayed_work(&d->mbm_over);
> +                     mbm_setup_overflow_handler(d);

I think this is the wrong approach. If the timer is about to fire you
essentially double the interval. So you better flush the work, which will
reschedule it if needed.

> +             }
> +             if (is_llc_occupancy_enabled() && cpu == d->mbm_work_cpu &&

That want's to be d->cbm_work_cpu, right?

> +                 has_busy_rmid(r, d)) {
> +                     cancel_delayed_work(&d->cqm_limbo);
> +                     cqm_setup_limbo_handler(d);

See above.

Thanks,

        tglx

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