Re: [PATCH v11 11/23] fs/resctrl: Add interface to disable a monitor event

[Reinette Chatre]

Hi Tony,

On 8/31/26 10:44 AM, Tony Luck wrote:
> resctrl currently assumes all monitor events are enabled before any domain
> is created, because per-domain state is allocated by the architecture's CPU
> hotplug callbacks. There is no way to disable an event once registered.
> 
> AET events are enumerated by the INTEL_PMT_TELEMETRY driver. To allow that
> driver to be a loadable module, resctrl must tolerate AET events appearing
> and disappearing, which requires the ability to disable an event when the
> driver is unloaded.
> 
> Add resctrl_disable_mon_event(). The architecture owns domain lifetime
> and knows mount state, so it is responsible for calling this only while
> resctrl is unmounted and for cleaning up any per-domain state. Document
> those requirements in the kerneldoc since they are not enforced in code.
> 
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
> ---
> v11:
> 	Add Reinette RB tag.

This is missing.

...

> +/**
> + * resctrl_disable_mon_event() - Disable monitoring event
> + * @eventid:	ID of the event
> + *
> + * The file system must not be mounted when disabling an event.

There are a bit more sharp corners with disabling of events since events
may be used while filesystem is unmounted. How about adding something like:

	"Never disable an event that may be accessed while the file system is unmounted."

Reinette