linux-kernel - Re: [PATCH v15 24/34] fs/resctrl: Report 'Unassigned' for MBM events in mbm

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Message-ID: <2c107793-1258-4276-8b29-03359fa605f2@amd.com>
Date: Wed, 23 Jul 2025 08:14:44 -0500
From: "Moger, Babu" <bmoger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, babu.moger@....com,
 corbet@....net, tony.luck@...el.com, james.morse@....com,
 tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
 dave.hansen@...ux.intel.com
Cc: Dave.Martin@....com, x86@...nel.org, hpa@...or.com,
 akpm@...ux-foundation.org, paulmck@...nel.org, rostedt@...dmis.org,
 Neeraj.Upadhyay@....com, david@...hat.com, arnd@...db.de, fvdl@...gle.com,
 seanjc@...gle.com, jpoimboe@...nel.org, pawan.kumar.gupta@...ux.intel.com,
 xin@...or.com, manali.shukla@....com, tao1.su@...ux.intel.com,
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 peterz@...radead.org, xin3.li@...el.com, kan.liang@...ux.intel.com,
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Subject: Re: [PATCH v15 24/34] fs/resctrl: Report 'Unassigned' for MBM events
 in mbm_event mode

Hi Reinette,

On 7/22/2025 9:05 PM, Reinette Chatre wrote:
> Hi Babu,
> 
> On 7/22/25 5:26 PM, Moger, Babu wrote:
>>
>> There is no redundant text now. . Users can look up about "mbm_event" from "mbm_assign_mode". Here is the complete diff.
>>
>> diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
>> index 446736dbd97f..01c33f62ce74 100644
>> --- a/Documentation/filesystems/resctrl.rst
>> +++ b/Documentation/filesystems/resctrl.rst
>> @@ -434,6 +434,12 @@ When monitoring is enabled all MON groups will also contain:
>>          for the L3 cache they occupy). These are named "mon_sub_L3_YY"
>>          where "YY" is the node number.
>>
>> +       When the 'mbm_event' counter assignment mode is enabled, reading
>> +       an MBM event of a MON group returns 'Unassigned' if no hardware
>> +       counter is assigned to it. For CTRL_MON groups, 'Unassigned' is
>> +       returned if none of the events in the CTRL_MON group or its
>> +       associated MON groups have assigned counters.
> 
> The "none of the events" could be interpreted wrongly with only one MBM event
> being read. How about the last sentence as:
> 	For CTRL_MON groups, 'Unassigned' is returned if the MBM event does not
> 	have an assigned counter in the CTRL_MON group nor in any of its associated
> 	MON groups.
> 

Yes. Looks good.
Thanks
Babu