Re: [PATCH v6 08/22] x86/resctrl: Introduce interface to display number of monitoring counters

[Reinette Chatre]

Hi Babu,

On 8/20/24 8:56 AM, Moger, Babu wrote:
> On 8/16/24 16:34, Reinette Chatre wrote:
> > On 8/6/24 3:00 PM, Babu Moger wrote:

> > > diff --git a/Documentation/arch/x86/resctrl.rst
> > > b/Documentation/arch/x86/resctrl.rst
> > > index d4ec605b200a..fe9f10766c4f 100644
> > > --- a/Documentation/arch/x86/resctrl.rst
> > > +++ b/Documentation/arch/x86/resctrl.rst
> > > @@ -291,6 +291,9 @@ with the following files:
> > >            as long as there are enough RMID counters available to support
> > > number
> > >            of monitoring groups.
> > >    +"num_mbm_cntrs":
> > > +    The number of monitoring counters available for assignment.
> > > +
> > >    "max_threshold_occupancy":
> > >            Read/write file provides the largest value (in
> > >            bytes) at which a previously used LLC_occupancy
> > > diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c
> > > b/arch/x86/kernel/cpu/resctrl/monitor.c
> > > index 5e8706ab6361..83329cefebf7 100644
> > > --- a/arch/x86/kernel/cpu/resctrl/monitor.c
> > > +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
> > > @@ -1242,6 +1242,8 @@ int __init rdt_get_mon_l3_config(struct
> > > rdt_resource *r)
> > >                r->mon.num_mbm_cntrs = (ebx & 0xFFFF) + 1;
> > >                if (WARN_ON(r->mon.num_mbm_cntrs > 64))
> > >                    r->mon.num_mbm_cntrs = 64;
> > > +
> > > +            resctrl_file_fflags_init("num_mbm_cntrs", RFTYPE_MON_INFO);
> >
> > The arch code should not access the resctrl file flags. This should be
> > moved to make
> > the MPAM support easier. With the arch code setting
> > r->mon.mbm_cntr_assignable the
> > fs code can use that to set the flags. Something similar to below patch is
> > needed:
> > https://lore.kernel.org/lkml/20240802172853.22529-27-james.morse@xxxxxxx/
>
> It is just moving the calls resctrl_file_fflags_init() to resctrl_init().
> The  rdt_resource fields are already setup here. Something like
> https://lore.kernel.org/lkml/20240802172853.22529-20-james.morse@xxxxxxx/
>
> I feel it is better done when MBAM fs/arch separation.

Indeed, it belongs with the rest of the mon state setup that is organized
as part of the MPAM work.

Reinette