linux-kernel - Re: [PATCH v8 10/13] x86/resctrl: Add sysfs interface to write mbm_total_bytes

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Message-ID: <20221107102134.255757-1-peternewman@google.com>
Date:   Mon,  7 Nov 2022 11:21:34 +0100
From:   Peter Newman <peternewman@...gle.com>
To:     babu.moger@....com
Cc:     akpm@...ux-foundation.org, bagasdotme@...il.com, bp@...en8.de,
        chang.seok.bae@...el.com, corbet@....net,
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        mingo@...hat.com, paulmck@...nel.org,
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Subject: Re: [PATCH v8 10/13] x86/resctrl: Add sysfs interface to write mbm_total_bytes_config

Hi Babu,

On Fri, Nov 04, 2022 at 03:01:09PM -0500, Babu Moger wrote:
> +	/*
> +	 * When an Event Configuration is changed, the bandwidth counters
> +	 * for all RMIDs and Events will be cleared by the hardware. The
> +	 * hardware also sets MSR_IA32_QM_CTR.Unavailable (bit 62) for
> +	 * every RMID on the next read to any event for every RMID.
> +	 * Subsequent reads will have MSR_IA32_QM_CTR.Unavailable (bit 62)
> +	 * cleared while it is tracked by the hardware. Clear the
> +	 * mbm_local and mbm_total counts for all the RMIDs.
> +	 */
> +	memset(d->mbm_local, 0, sizeof(struct mbm_state) * r->num_rmid);
> +	memset(d->mbm_total, 0, sizeof(struct mbm_state) * r->num_rmid);

Looking around, I can't find a reader for mbm_total anymore. It looks
like the last place it was used went away in James's recent change:

https://lore.kernel.org/all/20220902154829.30399-19-james.morse@arm.com

Are we supposed to be clearing arch_mbm_total now?

Thanks!
-Peter