Re: [RFC PATCH mpam mpam/snapshot/v6.12-rc1 v3 4/5] arm_mpam: Automatically synchronize the configuration of all sub-monitoring groups

[Zeng Heng]

On 2024/12/13 0:18, Dave Martin wrote:
> Hi,
>
> > @@ -3072,9 +3080,20 @@ struct mpam_write_config_arg {
> >   
> >   static int __write_config(void *arg)
> >   {
> > +	int closid_num = resctrl_arch_get_num_closid(NULL);
> >   	struct mpam_write_config_arg *c = arg;
> > +	u32 reqpartid, req_idx;
> > +
> > +	WARN_ON(c->partid >= closid_num);
> >   
> > -	mpam_reprogram_ris_partid(c->ris, c->partid, &c->comp->cfg[c->partid]);
> > +	/* Synchronize the configuration to each sub-monitoring group. */
> > +	for (req_idx = 0; req_idx < get_num_reqpartid_per_closid();
> > +	     req_idx++) {
> > +		reqpartid = req_idx * closid_num + c->partid;
> > +
> > +		mpam_reprogram_ris_partid(c->ris, reqpartid,
> > +					 &c->comp->cfg[c->partid]);
> > +	}
> >   
> >   	return 0;
> >   }
>
> I haven't decided whether this iteration belongs here or in
> mpam_resctrl.c.
>
> Your approach looks like it should work; I do it in
> resctrl_arch_update_one() instead [1], but I think the approaches are
> pretty much equivalent -- but let me know if you have any thoughts on
> it.

Yes, the actual functions of these two locations are essentially the
same. However, at the __write_config position, we can reduce the
repeated judgments of cfg[partid] in mpam_update_config() and also
decrease the times of smp_call remote invocations.

What about your option towards it?

Best regards,
Zeng Heng