linux-kernel - Re: [PATCH v2 10/23] x86/resctrl: Remove architecture copy of mbps

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Message-ID: <81977073-3b1b-b8e1-6aec-828225e3a531@intel.com>
Date:   Fri, 15 Oct 2021 15:27:45 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     James Morse <james.morse@....com>, <x86@...nel.org>,
        <linux-kernel@...r.kernel.org>
CC:     Fenghua Yu <fenghua.yu@...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>,
        Jamie Iles <jamie@...iainc.com>,
        "D Scott Phillips OS" <scott@...amperecomputing.com>,
        <lcherian@...vell.com>, <bobo.shaobowang@...wei.com>,
        <tan.shaopeng@...itsu.com>
Subject: Re: [PATCH v2 10/23] x86/resctrl: Remove architecture copy of
 mbps_val

Hi James,

On 10/1/2021 9:02 AM, James Morse wrote:
> The resctrl arch code provides a second configuration array mbps_val[]
> for the MBA software controller.
> 
> Since resctrl switched over to allocating and freeing its own array
> when needed, nothing uses the arch code version.

With the previous changes this is true, that this array is no longer 
used. Even so, the code removed in this patch is not just the usage of 
the array but also its management ... especially how and when it is 
reset. While the array is no longer used I think it is still important 
to ensure that all the array management is handled in the new mpbs_val 
array. Perhaps just help the reader by stating that the values of the 
new array never needs to be reset since it is always recreated while the 
previous array stuck around during umount/mount.

Reinette