Hi Babu,
On 10/9/24 10:39 AM, Babu Moger wrote:
> The mbm_cntr_assign mode provides a limited number of hardware counters
> that can be assigned to an RMID-event pair to monitor bandwidth while
> assigned. If all counters are in use, the kernel will show an error
> message: "Out of MBM assignable counters" when a new assignment is
> requested. To make space for a new assignment, users must unassign an
> already assigned counter.
>
> Introduce an interface that allows for the unassignment of counter IDs
> from both the group and the domain. Additionally, ensure that the global
> counter is released if it is no longer assigned to any domains.
Needs imperative tone ... "Release the global counter ..."
>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
...
> ---
> arch/x86/kernel/cpu/resctrl/internal.h | 2 +
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 56 ++++++++++++++++++++++++++
> 2 files changed, 58 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index 900e18aea2c4..6f388d20fb22 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -717,6 +717,8 @@ int resctrl_arch_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
> u32 cntr_id, bool assign);
> int rdtgroup_assign_cntr_event(struct rdt_resource *r, struct rdtgroup *rdtgrp,
> struct rdt_mon_domain *d, enum resctrl_event_id evtid);
> +int rdtgroup_unassign_cntr_event(struct rdt_resource *r, struct rdtgroup *rdtgrp,
> + struct rdt_mon_domain *d, enum resctrl_event_id evtid);
> void rdt_staged_configs_clear(void);
> bool closid_allocated(unsigned int closid);
> int resctrl_find_cleanest_closid(void);
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index e4f628e6fe65..791258adcbda 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -1945,6 +1945,62 @@ int rdtgroup_assign_cntr_event(struct rdt_resource *r, struct rdtgroup *rdtgrp,
> return ret;
> }
>
> +static bool mbm_cntr_assigned_to_domain(struct rdt_resource *r, u32 cntr_id)
> +{
> + struct rdt_mon_domain *d;
> +
> + list_for_each_entry(d, &r->mon_domains, hdr.list)
> + if (test_bit(cntr_id, d->mbm_cntr_map))
> + return 1;
> +
> + return 0;
> +}
> +
> +/*
> + * Unassign a hardware counter from the domain and the group.
Not sure ... maybe "Unassign a hardware counter associated with @evtid from
the domain and the group."?
> + * Counter will be unassigned in all the domains if rdt_mon_domain is NULL
Please use imperative tone: "Unassign the counter from all the domains ...."
> + * else the counter will be assigned to specific domain.
copy&paste error?
"assigned to specific domain" -> "unassign from specific domain"?
> + * Global counter will be freed once it is unassigned from all the domains.
Needs imperative tone.
> + */
> +int rdtgroup_unassign_cntr_event(struct rdt_resource *r, struct rdtgroup *rdtgrp,
> + struct rdt_mon_domain *d, enum resctrl_event_id evtid)
> +{
> + int index = MBM_EVENT_ARRAY_INDEX(evtid);
> + int cntr_id = rdtgrp->mon.cntr_id[index];
> + int ret;
> +
> + /* Return early if the counter is unassigned already */
> + if (cntr_id == MON_CNTR_UNSET)
> + return 0;
> +
> + if (!d) {
> + list_for_each_entry(d, &r->mon_domains, hdr.list) {
> + ret = resctrl_arch_config_cntr(r, d, evtid, rdtgrp->mon.rmid,
> + rdtgrp->closid, cntr_id, false);
> + if (ret)
> + goto out_done_unassign;
> +
> + clear_bit(cntr_id, d->mbm_cntr_map);
> + }
> + } else {
> + ret = resctrl_arch_config_cntr(r, d, evtid, rdtgrp->mon.rmid,
> + rdtgrp->closid, cntr_id, false);
> + if (ret)
> + goto out_done_unassign;
> +
> + clear_bit(cntr_id, d->mbm_cntr_map);
Please see comment to previous patch about the duplicate snippets. Snippets can be
replaced with single function that also resets architectural state.
> + }
> +
> + /* Update the counter bitmap */
What is the update?
> + if (!mbm_cntr_assigned_to_domain(r, cntr_id)) {
> + mbm_cntr_free(r, cntr_id);
> + rdtgrp->mon.cntr_id[index] = MON_CNTR_UNSET;
> + }
> +
> +out_done_unassign:
> + return ret;
> +}
> +
> /* rdtgroup information files for one cache resource. */
> static struct rftype res_common_files[] = {
> {
Reinette
