linux-kernel - Re: [PATCH v1] fs/resctrl: Add missing kconfig entry for CONFIG_RESCTRL_ASSIGN

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Message-ID: <050fcf3b-d390-4692-b944-2d59a71888e4@arm.com>
Date: Thu, 15 Jan 2026 15:46:27 +0000
From: Ben Horgan <ben.horgan@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, linux-kernel@...r.kernel.org
Cc: tony.luck@...el.com, Dave.Martin@....com, james.morse@....com,
 babu.moger@....com, bp@...en8.de
Subject: Re: [PATCH v1] fs/resctrl: Add missing kconfig entry for
 CONFIG_RESCTRL_ASSIGN_FIXED

Hi Reinette,

On 1/15/26 15:37, Reinette Chatre wrote:
> Hi Ben,
> 
> On 1/15/26 2:32 AM, Ben Horgan wrote:
>> On 1/14/26 19:09, Reinette Chatre wrote:
>>> On 1/13/26 6:49 AM, Ben Horgan wrote:
>>>> The commit 3b497c3f4f04 ("fs/resctrl: Introduce the interface to display
>>>> monitoring modes") introduced CONFIG_RESCTRL_ASSIGN_FIXED but did not add
>>>> the kconfig entry. Add this.
>>>>
>>>> Also, take the opportunity ensure that any user attempt to change the
>>>> assign mode fails from the resctrl code rather than delegating to the arch
>>>> specific code and let the user know by adding a message in last_cmd_status.
>>>
>>> Why *any* attempt? Avoiding delegating to arch seems ok as a goal but this change
>>> additionally changes interface with user space. Current behavior when user writes
>>> existing mode to the file is to just return success. For example, if current mode
>>> is "default" and user writes "default". This patch changes this behavior to fail
>>> instead. Is this intended?
>>
>> Intended but as you point out, it would be best to accept the current
>> value without error for maximum compatibility between architectures.
>> I'll update the config option help text to reflect this. Was the help
>> text also discussed previously?
> 
> It is not clear to me which help text you are referring to. Could you
> please point me to it?

I just mean the description in Kconfig. Maybe I'm using the wrong
terminology?

>From this patch:
    help
     Enabled by the architecture when the counter assignment mode is not
     configurable. This ensures that counter assignment is not
advertised as
     configurable and configuration attempts fail.

> 
> Reinette

Thanks,

Ben