linux-kernel - Re: [PATCH v2 18/45] arm_mpam: resctrl: Implement resctrl_arch_reset_all

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Message-ID: <4152d2bb-098c-48db-94f0-a90306700266@arm.com>
Date: Tue, 6 Jan 2026 11:19:32 +0000
From: Ben Horgan <ben.horgan@....com>
To: Jonathan Cameron <jonathan.cameron@...wei.com>
Cc: amitsinght@...vell.com, baisheng.gao@...soc.com,
 baolin.wang@...ux.alibaba.com, carl@...amperecomputing.com,
 dave.martin@....com, david@...nel.org, dfustini@...libre.com,
 fenghuay@...dia.com, gshan@...hat.com, james.morse@....com,
 kobak@...dia.com, lcherian@...vell.com,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
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 quic_jiles@...cinc.com, reinette.chatre@...el.com, rohit.mathew@....com,
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 joey.gouly@....com, suzuki.poulose@....com, kvmarm@...ts.linux.dev
Subject: Re: [PATCH v2 18/45] arm_mpam: resctrl: Implement
 resctrl_arch_reset_all_ctrls()

Hi Jonathan,

On 1/5/26 17:51, Jonathan Cameron wrote:
> On Fri, 19 Dec 2025 18:11:20 +0000
> Ben Horgan <ben.horgan@....com> wrote:
> 
>> From: James Morse <james.morse@....com>
>>
>> We already have a helper for resetting an mpam class and component.  Hook
>> it up to resctrl_arch_reset_all_ctrls() and the domain offline path.
>>
>> Signed-off-by: James Morse <james.morse@....com>
>> Signed-off-by: Ben Horgan <ben.horgan@....com>
> I left all the context as my one comment on this is I don't see a reason
> to expose mpam_reset_class()  Only the _locked() variant ever seems to be
> used outside of mpam_devices.c
> 
>> ---

>> diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
>> index 554e4887ba81..b9a739abb101 100644
>> --- a/drivers/resctrl/mpam_internal.h
>> +++ b/drivers/resctrl/mpam_internal.h
>> @@ -389,6 +389,13 @@ extern u8 mpam_pmg_max;
>>  void mpam_enable(struct work_struct *work);
>>  void mpam_disable(struct work_struct *work);
>>  
>> +/* Reset all the RIS in a class, optionally while holding cpus_read_lock() */
>> +void mpam_reset_class_locked(struct mpam_class *class);
>> +void mpam_reset_class(struct mpam_class *class);
> 
> Not clear from this patch why we need to expose mpam_reset_class()

Good spot. That's not required in this series, so I will stop exposing it.


Thanks,

Ben