Re: [PATCH v5 2/2] x86,fs/resctrl: Keep mbm_assign_mode in default mode at boot

[Babu Moger]

Hi Reinette,

On 10/27/26 11:36, Reinette Chatre wrote:
> Hi Babu,
>
> On 10/27/26 7:48 AM, Babu Moger wrote:
> > On 10/26/26 19:15, Reinette Chatre wrote:
> > > On 10/21/26 4:58 PM, Babu Moger wrote:
>
> ...
>
> > > > +  # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
> > > > +  [default]
> > > > +  mbm_event
> > > > +
> > > > +The "default" mode is enabled. "mbm_event" is supported but not enabled.
> > > >    +b. Enable "mbm_event" mode. Switching the mbm_assign_mode may
> > > > +reset all the MBM counters (and thus all MBM events) of all the resctrl groups.
> > > > +::
> > > > +
> > > > +  # echo "mbm_event" > /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
> > > >      # cat /sys/fs/resctrl/info/L3_MON/mbm_assign_mode
> > > >      [mbm_event]
> > > >      default
> > > >    
> > >
> > > The above changes could be merged together under a single step "a" that
> > > will significantly reduce the churn when considering this is a stable patch.
> >
> > Yes. We can. But because of auto assign is not enabled on mode switch, we still have to touch few steps. Your choice.
>
> Understood. The benefit here is that the patch will only change actual information.
>
> Specifically, changes like the two below that just updates the letter
> associated with the step:
>
> > > > -b. Check how many assignable counters are supported.
> > > > +c. Check how many assignable counters are supported.
> > > >    ::
> > > >        # cat /sys/fs/resctrl/info/L3_MON/num_mbm_cntrs
> > > >      0=32;1=32

Yea. This will be dropped.>
> and
>
> > > >    -c. Check how many assignable counters are available for assignment in each domain.
> > > > +d. Check how many assignable counters are available for assignment in each domain.
> > > >    ::
>
> will be dropped from the patch. They distract from the core change and do not
> seem appropriate for a patch headed to stable.

Actually, the step (d) will be partially dropped as assignable counters 
changed from 30 to 32 without auto-assignment.

  # cat /sys/fs/resctrl/info/L3_MON/available_mbm_cntrs
-  0=30;1=30
+  0=32;1=32


Will send the updated series later this week.

Also, noticed a minor typo:

-  # cat /sys/fs/resctrl/mbm_L3_assignment
+  # cat /sys/fs/resctrl/mbm_L3_assignments


Thanks
Babu