Hi Babu,
On 1/22/25 12:20 PM, Babu Moger wrote:
> In mbm_cntr_assign mode hardware counters are assigned/unassigned to an
> MBM event of a monitor group. Hardware counters are assigned/unassigned
> at monitoring domain level.
>
> Manage a monitoring domain's hardware counters using a per monitoring
> domain array of struct mbm_cntr_cfg that is indexed by the hardware
> counter ID. A hardware counter's configuration contains the MBM event
Something strange in this changelog with a few random \t in the text.
> ID and points to the monitoring group that it is assigned to, with a
> NULL pointer meaning that the hardware counter is available for assignment.
>
> There is no direct way to determine which hardware counters are assigned
... another \t above
> to a particular monitoring group. Check every entry of every hardware
> counter configuration array in every monitoring domain to query which
... one more \t above
> MBM events of a monitoring group is tracked by hardware. Such queries
> are acceptable because of a very small number of assignable counters.
It is not obvious what "very small number" means. Is it possible to give
a range to help reader understand the motivation?
>
> Suggested-by: Peter Newman <peternewman@xxxxxxxxxx>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
> ---
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 11 +++++++++++
> include/linux/resctrl.h | 14 ++++++++++++++
> 2 files changed, 25 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 18110a1afb6d..75a3b56996ca 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -4009,6 +4009,7 @@ static void __init rdtgroup_setup_default(void)
>
> static void domain_destroy_mon_state(struct rdt_mon_domain *d)
> {
> + kfree(d->cntr_cfg);
> bitmap_free(d->rmid_busy_llc);
> kfree(d->mbm_total);
> kfree(d->mbm_local);
> @@ -4082,6 +4083,16 @@ static int domain_setup_mon_state(struct rdt_resource *r, struct rdt_mon_domain
> return -ENOMEM;
> }
> }
> + if (is_mbm_enabled() && r->mon.mbm_cntr_assignable) {
> + tsize = sizeof(*d->cntr_cfg);
> + d->cntr_cfg = kcalloc(r->mon.num_mbm_cntrs, tsize, GFP_KERNEL);
> + if (!d->cntr_cfg) {
> + bitmap_free(d->rmid_busy_llc);
> + kfree(d->mbm_total);
> + kfree(d->mbm_local);
> + return -ENOMEM;
> + }
> + }
>
> return 0;
> }
> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
> index 511cfce8fc21..9a54e307d340 100644
> --- a/include/linux/resctrl.h
> +++ b/include/linux/resctrl.h
> @@ -94,6 +94,18 @@ struct rdt_ctrl_domain {
> u32 *mbps_val;
> };
>
> +/**
> + * struct mbm_cntr_cfg - assignable counter configuration
> + * @evtid: MBM event to which the counter is assigned. Only valid
> + * if @rdtgroup is not NULL.
> + * @rdtgroup: resctrl group assigned to the counter. NULL if the
> + * counter is free.
> + */
> +struct mbm_cntr_cfg {
> + enum resctrl_event_id evtid;
> + struct rdtgroup *rdtgrp;
> +};
> +
$ scripts/kernel-doc -v -none include/linux/resctrl.h
...
include/linux/resctrl.h:107: warning: Function parameter or struct member 'rdtgrp' not described in 'mbm_cntr_cfg'
include/linux/resctrl.h:107: warning: Excess struct member 'rdtgroup' description in 'mbm_cntr_cfg'
...
> /**
> * struct rdt_mon_domain - group of CPUs sharing a resctrl monitor resource
> * @hdr: common header for different domain types
> @@ -105,6 +117,7 @@ struct rdt_ctrl_domain {
> * @cqm_limbo: worker to periodically read CQM h/w counters
> * @mbm_work_cpu: worker CPU for MBM h/w counters
> * @cqm_work_cpu: worker CPU for CQM h/w counters
> + * @cntr_cfg: assignable counters configuration
> */
> struct rdt_mon_domain {
> struct rdt_domain_hdr hdr;
> @@ -116,6 +129,7 @@ struct rdt_mon_domain {
> struct delayed_work cqm_limbo;
> int mbm_work_cpu;
> int cqm_work_cpu;
> + struct mbm_cntr_cfg *cntr_cfg;
> };
>
> /**
Reinette
