Hi Babu,
On 7/8/25 3:17 PM, Babu Moger wrote:
> The "mbm_event" counter assignment mode offers "num_mbm_cntrs" number of
> counters that can be assigned to RMID, event pairs and monitor bandwidth
> usage as long as it is assigned. If all the counters are in use, the
> kernel logs the error message "Unable to allocate counter in domain" in
> /sys/fs/resctrl/info/last_cmd_status when a new assignment is requested.
>
> To make space for a new assignment, users must unassign an already
> assigned counter and retry the assignment again.
>
> Add the functionality to unassign and free the counters in the domain.
>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
...
> diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
> index bb074773420d..6c0410cf0195 100644
> --- a/fs/resctrl/monitor.c
> +++ b/fs/resctrl/monitor.c
> @@ -1022,6 +1022,14 @@ static int mbm_cntr_alloc(struct rdt_resource *r, struct rdt_mon_domain *d,
> return -ENOSPC;
> }
>
> +/*
> + * mbm_cntr_free() - Clear the counter ID configuration details in the domain @d.
> + */
> +static void mbm_cntr_free(struct rdt_mon_domain *d, int cntr_id)
> +{
> + memset(&d->cntr_cfg[cntr_id], 0, sizeof(*d->cntr_cfg));
> +}
> +
> /*
> * rdtgroup_alloc_config_cntr() - Allocate a counter ID and configure it for the
> * event pointed to by @mevt and the resctrl group @rdtgrp within the domain @d.
> @@ -1083,3 +1091,42 @@ int rdtgroup_assign_cntr_event(struct rdt_mon_domain *d, struct rdtgroup *rdtgrp
>
> return ret;
> }
> +
> +/*
> + * rdtgroup_free_config_cntr() - Unassign and reset the counter ID configuration
rdtgroup_free_config_cntr() -> rdtgroup_free_unassign_cntr() ?
> + * for the event pointed to by @mevt within the domain @d and resctrl group @rdtgrp.
@mevt -> @evtid
> + */
> +static void rdtgroup_free_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
> + struct rdtgroup *rdtgrp, enum resctrl_event_id evtid)
> +{
> + int cntr_id;
> +
> + cntr_id = mbm_cntr_get(r, d, rdtgrp, evtid);
> +
> + /* If there is no cntr_id assigned, nothing to do */
> + if (cntr_id < 0)
> + return;
> +
> + resctrl_config_cntr(r, d, evtid, rdtgrp->mon.rmid, rdtgrp->closid,
> + cntr_id, false);
> +
> + mbm_cntr_free(d, cntr_id);
> +}
> +
> +/*
> + * rdtgroup_unassign_cntr_event() - Unassign a hardware counter associated with
> + * the event structure @mevt from the domain @d and the group @rdtgrp. Unassign
> + * the counters from all the domains if @d is NULL else unassign from @d.
> + */
> +void rdtgroup_unassign_cntr_event(struct rdt_mon_domain *d, struct rdtgroup *rdtgrp,
> + struct mon_evt *mevt)
> +{
> + struct rdt_resource *r = resctrl_arch_get_resource(mevt->rid);
> +
> + if (!d) {
> + list_for_each_entry(d, &r->mon_domains, hdr.list)
> + rdtgroup_free_config_cntr(r, d, rdtgrp, mevt->evtid);
> + } else {
> + rdtgroup_free_config_cntr(r, d, rdtgrp, mevt->evtid);
> + }
> +}
Reinette
