Re: [PATCH v4 00/41] arm_mpam: Add KVM/arm64 and resctrl glue code

Ben Horgan
2026-02-24T15:27:41Z

Hi Zeng,

On 2/24/26 14:19, Ben Horgan wrote:
> Hi Zeng,
>
> On 2/24/26 11:03, Zeng Heng wrote:
>> Hi Ben,
>>
>> On 2026/2/16 20:22, Ben Horgan wrote:
>>> Hi Zeng,
>>>
>>> On 2/14/26 09:40, Zeng Heng wrote:
>>>> Hi Ben,
>>>>
>>>> On 2026/2/4 5:43, Ben Horgan wrote:
>>> [...]
>>>>>
>>>>> Based on:
>>>>> [1] git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/cache
>>>>> (To include telemetry code which changes the resctrl arch interface)
>>>>>
>>>>> The series can be retrieved from:
>>>>> https://gitlab.arm.com/linux-arm/linux-bh.git mpam_resctrl_glue_v4
>>>>> (Final commit is a fix already in 6.19-rc8)
[...]
>>>> [   10.978497] mpam:mpam_resctrl_pick_caches: class 255 is not a cache
>>>> [   10.980470] mpam:mpam_resctrl_pick_mba: class 2 is before L3

This debug message was removed in v4 of the series.
v3 has it: https://lore.kernel.org/linux-arm-kernel/20260112165914.4086692-28-ben.horgan@arm.com/
v4 doesn't: https://lore.kernel.org/linux-arm-kernel/20260203214342.584712-27-ben.horgan@arm.com/

Do you know which version of the series you were running?

>>>> [   10.980472] mpam:mpam_resctrl_pick_mba: class 3 has no bandwidth
>>>> control
>>>> [   10.997406] mpam:topology_matches_l3: class 255 component 0 has
>>>> Mismatched CPU mask with L3 equivalent
>>>> [   10.997411] mpam:mpam_resctrl_pick_mba: class 255 topology doesn't
>>>> match L3
>>>> [   10.997415] mpam:mpam_resctrl_pick_counters: class 2 is before L3
>>>> [   11.024109] mpam:topology_matches_l3: class 3 component 276 has
>>>> Mismatched CPU mask with L3 equivalent
>>>> [   11.024114] mpam:class_has_usable_mbwu: monitors usable in free-
>>>> running mode
>>>
>>> mbwu enabled?
>>
>> The fact that the number of monitors merely satisfies the conditions for
>> free-running mode does not imply that the MBWU functionality can be
>> successfully mounted. The specific reasons are explained above.
>
> True
>
>>
>>>
>>>> [   11.063882] mpam:topology_matches_l3: class 255 component 0 has
>>>> Mismatched CPU mask with L3 equivalent
>>>> [   11.113183] mpam:mpam_resctrl_alloc_domain: Skipped monitor domain
>>>> online - no monitors
>>>> [   11.113189] MPAM enabled with 32 PARTIDs and 4 PMGs
>>>>
>>>>
>>
>> Sorry for the late reply. And this is my first day back from a long
>> vacation.
>
> No problem. Hope you had a good holiday.
>
>>
>>
>> Best regards,
>> Zeng Heng
>
> Thanks,
>
> Ben
>
>

Thanks,

Ben