linux-kernel - Re: [PATCH 04/33] ACPI / PPTT: Find cache level by cache-id

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Message-ID: <2d1bc3de-8d4d-47e4-8f3b-618881128b1d@nvidia.com>
Date: Wed, 12 Nov 2025 12:23:49 -0800
From: Fenghua Yu <fenghuay@...dia.com>
To: Ben Horgan <ben.horgan@....com>, james.morse@....com
Cc: amitsinght@...vell.com, baisheng.gao@...soc.com,
 baolin.wang@...ux.alibaba.com, bobo.shaobowang@...wei.com,
 carl@...amperecomputing.com, catalin.marinas@....com, dakr@...nel.org,
 dave.martin@....com, david@...hat.com, dfustini@...libre.com,
 gregkh@...uxfoundation.org, gshan@...hat.com, guohanjun@...wei.com,
 jeremy.linton@....com, jonathan.cameron@...wei.com, kobak@...dia.com,
 lcherian@...vell.com, lenb@...nel.org, linux-acpi@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 lpieralisi@...nel.org, peternewman@...gle.com, quic_jiles@...cinc.com,
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 tan.shaopeng@...itsu.com, will@...nel.org, xhao@...ux.alibaba.com
Subject: Re: [PATCH 04/33] ACPI / PPTT: Find cache level by cache-id



On 11/7/25 04:34, Ben Horgan wrote:
> From: James Morse <james.morse@....com>
> 
> The MPAM table identifies caches by id. The MPAM driver also wants to know
> the cache level to determine if the platform is of the shape that can be
> managed via resctrl. Cacheinfo has this information, but only for CPUs that
> are online.
> 
> Waiting for all CPUs to come online is a problem for platforms where
> CPUs are brought online late by user-space.
> 
> Add a helper that walks every possible cache, until it finds the one
> identified by cache-id, then return the level.
> 
> Signed-off-by: James Morse <james.morse@....com>
> Signed-off-by: Ben Horgan <ben.horgan@....com>

Reviewed-by: Fenghua Yu <fenghuay@...dia.com>
Tested-by: Fenghua Yu <fenghuay@...dia.com>

Thanks.

-Fenghua