Re: [PATCH v2 27/45] arm_mpam: resctrl: Add support for csu counters

Jonathan Cameron
2026-01-06T12:41:02Z

On Fri, 19 Dec 2025 18:11:29 +0000
Ben Horgan <ben.horgan@arm.com> wrote:

> From: James Morse <james.morse@arm.com>
>
> resctrl exposes a counter via a file named llc_occupancy. This isn't really
> a counter as its value goes up and down, this is a snapshot of the cache
> storage usage monitor.
>
> Add some picking code to find a cache as close as possible to the L3 that
> supports the CSU monitor.
>
> If there is an L3, but it doesn't have any controls, force the L3 resource
> to exist. The existing topology_matches_l3() and
> mpam_resctrl_domain_hdr_init() code will ensure this looks like the L3,
> even if the class belongs to a later cache.
>
> Signed-off-by: James Morse <james.morse@arm.com>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>