linux-kernel - Re: [PATCH v2 17/35] x86/resctrl: Move mbm_cfg_mask to struct rdt

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Message-ID: <6b863124-d1ce-429f-b1b6-73fc48978a6d@arm.com>
Date: Fri, 14 Jun 2024 14:57:58 +0100
From: James Morse <james.morse@....com>
To: Dave Martin <Dave.Martin@....com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Cc: Fenghua Yu <fenghua.yu@...el.com>,
 Reinette Chatre <reinette.chatre@...el.com>,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Borislav Petkov <bp@...en8.de>, H Peter Anvin <hpa@...or.com>,
 Babu Moger <Babu.Moger@....com>, shameerali.kolothum.thodi@...wei.com,
 D Scott Phillips OS <scott@...amperecomputing.com>,
 carl@...amperecomputing.com, lcherian@...vell.com,
 bobo.shaobowang@...wei.com, "Shaopeng Tan (Fujitsu)"
 <tan.shaopeng@...itsu.com>, baolin.wang@...ux.alibaba.com,
 Jamie Iles <quic_jiles@...cinc.com>, Xin Hao <xhao@...ux.alibaba.com>,
 Peter Newman <peternewman@...gle.com>, dfustini@...libre.com,
 amitsinght@...vell.com, David Hildenbrand <david@...hat.com>,
 Rex Nie <rex.nie@...uarmicro.com>
Subject: Re: [PATCH v2 17/35] x86/resctrl: Move mbm_cfg_mask to struct
 rdt_resource

Hi Dave,

On 26/04/2024 16:08, Dave Martin wrote:
> From: James Morse <james.morse@....com>
> 
> The mbm_cfg_mask field lists the bits that user-space can set when
> configuring an event. This value is output via the last_cmd_status
> file.
> 
> Once the filesystem parts of resctrl are moved to live in /fs/, the
> struct rdt_hw_resource is inaccessible to the filesystem code. Because
> this value is output to user-space, it has to be accessible to the
> filesystem code.
> 
> Move it to struct rdt_resource.


>  * Reword comments to avoid being overly arch-specific.
> 
>    Is the _content_ of mbm_cfg_mask arch-independent?

This comes from the mbm_total_bytes_config, nothing in Documentation/arch/x86/resctrl.rst
says this is AMD specific, so it can be assumed to be defined by resctrl, but depending on
some hardware feature.

I'm not sure we can make this retroactively platform specific.


Thanks,

James