Re: [PATCH v8 17/25] x86/resctrl: Add the interface to assign/update counter assignment

[Moger, Babu]

Hi Reinette,

On 10/21/2024 10:31 AM, Reinette Chatre wrote:
> Hi Babu,
>
> On 10/21/24 7:40 AM, Moger, Babu wrote:
> > On 10/18/24 10:59, Reinette Chatre wrote:
> > > On 10/17/24 3:56 PM, Moger, Babu wrote:
> > > > On 10/15/2024 10:25 PM, Reinette Chatre wrote:
> > > > > On 10/9/24 10:39 AM, Babu Moger wrote:
> > >
> > > > > > + */
> > > > > > +int rdtgroup_assign_cntr_event(struct rdt_resource *r, struct rdtgroup *rdtgrp,
> > > > > > +                   struct rdt_mon_domain *d, enum resctrl_event_id evtid)
> > > > > > +{
> > > > > > +    int index = MBM_EVENT_ARRAY_INDEX(evtid);
> > > > > > +    int cntr_id = rdtgrp->mon.cntr_id[index];
> > > > > > +    int ret;
> > > > > > +
> > > > > > +    /*
> > > > > > +     * Allocate a new counter id to the event if the counter is not
> > > > > > +     * assigned already.
> > > > > > +     */
> > > > > > +    if (cntr_id == MON_CNTR_UNSET) {
> > > > > > +        cntr_id = mbm_cntr_alloc(r);
> > > > > > +        if (cntr_id < 0) {
> > > > > > +            rdt_last_cmd_puts("Out of MBM assignable counters\n");
> > > > > > +            return -ENOSPC;
> > > > > > +        }
> > > > > > +        rdtgrp->mon.cntr_id[index] = cntr_id;
> > > > > > +    }
> > > > > > +
> > > > > > +    if (!d) {
> > > > > > +        list_for_each_entry(d, &r->mon_domains, hdr.list) {
> > > > > > +            ret = resctrl_arch_config_cntr(r, d, evtid, rdtgrp->mon.rmid,
> > > > > > +                               rdtgrp->closid, cntr_id, true);
> > > > > > +            if (ret)
> > > > > > +                goto out_done_assign;
> > > > > > +
> > > > > > +            set_bit(cntr_id, d->mbm_cntr_map);
> > > > >
> > > > > The code pattern above is repeated four times in this work, twice in
> > > > > rdtgroup_assign_cntr_event() and twice in rdtgroup_unassign_cntr_event(). This
> > > > > duplication should be avoided. It can be done in a function that also resets
> > > > > the architectural state.
> > > >
> > > > Are you suggesting to combine rdtgroup_assign_cntr_event() and rdtgroup_unassign_cntr_event()?
> > >
> > > No. My comment was about the following pattern that is repeated four times:
> > > 	...
> > > 	ret = resctrl_arch_config_cntr(...)
> > > 	if (ret)
> > > 		...
> > > 	set_bit()/clear_bit()
> > > 	...
> >
> > ok.
> >
> >
> > > > It can be done. We need a flag to tell if it is a assign or unassign.
> > >
> > > There is already a flag that is used by resctrl_arch_config_cntr(), the same parameters
> > > as resctrl_arch_config_cntr() can be used for a wrapper that just calls
> > > resctrl_arch_config_cntr() directly and uses that same flag to
> > > select between set_bit() and clear_bit(). This wrapper can then also include
> > > the reset of architectural state.
> >
> > ok. Got it, It will look like this.
> >
> >
> > +/*
> > + * Wrapper to configure the counter in a domain.
> > + */
>
> Please replace comment with a description of what the function does.

sure.

> > +static int rdtgroup_config_cntr(struct rdt_resource *r,struct
>
> While it keeps being a challenge to get naming right I do think this
> can start by replacing "rdtgroup" with "resctrl" (specifically,
> "rdtgroup_config_cntr() -> resctrl_config_cntr()") because, as seen
> with the parameters passed, this has nothing to do with rdtgroup.

Sure.

> > rdt_mon_domain *d,
> > +                               enum resctrl_event_id evtid, u32 rmid, u32
> > closid,
> > +                               u32 cntr_id, bool assign)
> > +{
> > +       int ret;
> > +
> > +       ret = resctrl_arch_config_cntr(r, d, evtid, rmid, closid, cntr_id,
> > assign);
> > +       if (ret)
> > +               return ret;
> > +
> > +       if (assign)
> > +               __set_bit(cntr_id, d->mbm_cntr_map);
> > +       else
> > +               __clear_bit(cntr_id, d->mbm_cntr_map);
> > +
> > +       /*
> > +        * Reset the architectural state so that reading of hardware
> > +        * counter is not considered as an overflow in next update.
> > +        */
> > +       resctrl_arch_reset_rmid(r, d, closid, rmid, evtid);
> > +
> > +       return ret;
> > +}
> > +
>
> Yes, this looks good. Thank you.

Thanks-
- Babu Moger