linux-kernel - Re: [PATCH v5 00/21] x86/resctrl: Make resctrl_arch_rmid

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Message-ID: <4ca8b7c8-0b67-d3a0-73c9-a2c4974cdcac@arm.com>
Date:   Fri, 2 Sep 2022 16:47:58 +0100
From:   James Morse <james.morse@....com>
To:     Reinette Chatre <reinette.chatre@...el.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,
        D Scott Phillips OS <scott@...amperecomputing.com>,
        lcherian@...vell.com, bobo.shaobowang@...wei.com,
        tan.shaopeng@...itsu.com, Jamie Iles <quic_jiles@...cinc.com>,
        Cristian Marussi <cristian.marussi@....com>,
        Xin Hao <xhao@...ux.alibaba.com>, xingxin.hx@...nanolis.org,
        baolin.wang@...ux.alibaba.com
Subject: Re: [PATCH v5 00/21] x86/resctrl: Make resctrl_arch_rmid_read()
 return values in bytes

Hi Reinette,

On 23/08/2022 18:20, Reinette Chatre wrote:
> On 6/22/2022 9:46 AM, James Morse wrote:
>> The aim of this series is to insert a split between the parts of the monitor
>> code that the architecture must implement, and those that are part of the
>> resctrl filesystem. The eventual aim is to move all filesystem parts out
>> to live in /fs/resctrl, so that resctrl can be wired up for MPAM.
>>
>> What's MPAM? See the cover letter of a previous series. [1]
>>
>> The series adds domain online/offline callbacks to allow the filesystem to
>> manage some of its structures itself, then moves all the 'mba_sc' behaviour
>> to be part of the filesystem.
>> This means another architecture doesn't need to provide an mbps_val array.
>> As its all software, the resctrl filesystem should be able to do this without
>> any help from the architecture code.
>>
>> Finally __rmid_read() is refactored to be the API call that the architecture
>> provides to read a counter value. All the hardware specific overflow detection,
>> scaling and value correction should occur behind this helper.
>>
> 
> Thank you for your patience as I was offline for a while. 

No problem,


> This series looks good to me. I have one remaining comment that I provided
> in reply to "[07/21] x86/resctrl: Abstract and use supports_mba_mbps()" where
> it seems to me that an existing issue could easily be addressed in the new
> function. 

Yup, that made sense to me.


> I do not have tests for the software controller and only did basic sanity
> checks. It would be great if the folks using this feature could test this
> series.
> 
> Thank you very much. From my side it looks good:
> 
> Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>


Thanks!

James