Re: [PATCH v5 RESEND 7/7] fs/resctrl: Add info/moveable_mon_group

[Reinette Chatre]

Hi Jinjie and Ben,

On 11/10/26 5:39 AM, Jinjie Ruan wrote:
> Moving a MON group into the mon_groups directory of another CTRL_MON
> group changes the CLOSID of the group while its RMID stays the same.
> Where the RMID is only meaningful together with the CLOSID, as on arm64
> MPAM, the move changes the RMID index of the group and is rejected with
> -EOPNOTSUPP.
> 
> Userspace cannot tell whether the move is supported without trying it.
> Add "info/moveable_mon_group", which reads 1 when a MON group can be
> moved to another CTRL_MON group and 0 when the move is rejected, and
> refer to it where resctrl.rst describes the move.
> 
> Suggested-by: Ben Horgan <ben.horgan@xxxxxxx>
> Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>

Do you find that this binary "supported/unsupported" accurately captures
everything that MPAM may ever want to do in this area? Could it be that, for
example, one day MPAM may be asked to support the move of a monitor group to
support scenarios where the reset of monitor counts is acceptable to the customer
and availability of PMG will be managed as part of the scenario needing support?

When adding a new interface it helps to consider future possible changes and
aim to create an interface that solves the immediate problem while leaving room
for future enhancements. If we do not do that the interface becomes a maze due
to new files just being added to address the problem of the day.

I would like to propose that this patch be submitted separately with the goal
to obtain more feedback on the new interface. 

Reinette