RE: RE: [PATCH 1/2] x86/resctrl: Add io_alloc_min_cbm_all interface for CBM reset

[Luck, Tony]

> > # echo "L2:*=fff" > schemata
> >
> > would work,. But
> >
> > # echo "L2:*=ffff" > schemata
> >
> > would try to set unimplemented bits on some cores and would fail.
>
>
> I would consider this a user error, as the user is expected to know the
> supported value for the domain.
> This situation can occur even now — we simply report the error and exit.

Babu

Maybe it was a poor explanation on my part.

On a hybrid P-core/E-core system with different L2 cache topology schemata
may look like this (8 L2 domains of one type, 4 L2 domains of other type.

$ cat schemata
L2:0=ffff;1=ffff;2=ffff;3=ffff;4=ffff;5=ffff;6=ffff;7=ffff;8=7f;9=7f;10=7f;11=7f

The proposed wildcard syntax is only useful to set all domains to a value
that is legal for all domains. It cannot be used for the "reset back to defaults"
case because different domains have different defaults.

-Tony