Hi Reinette,
On 5/22/25 17:49, Reinette Chatre wrote:
> Hi Babu,
>
> On 5/15/25 3:51 PM, Babu Moger wrote:
>> The mbm_cntr_assign mode offers "num_mbm_cntrs" number of counters that
>> can be assigned to an RMID, event pair and monitor the bandwidth as long
>> as it is assigned. If all the counters are in use, the kernel will log 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>
>> ---
> ...
>
>> ---
>> fs/resctrl/internal.h | 2 ++
>> fs/resctrl/monitor.c | 60 +++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 62 insertions(+)
>>
>> diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
>> index ce4fcac91937..64ddc107fcab 100644
>> --- a/fs/resctrl/internal.h
>> +++ b/fs/resctrl/internal.h
>> @@ -379,6 +379,8 @@ int resctrl_find_cleanest_closid(void);
>>
>> int resctrl_assign_cntr_event(struct rdt_resource *r, struct rdt_mon_domain *d,
>> struct rdtgroup *rdtgrp, enum resctrl_event_id evtid);
>> +int resctrl_unassign_cntr_event(struct rdt_resource *r, struct rdt_mon_domain *d,
>> + struct rdtgroup *rdtgrp, enum resctrl_event_id evtid);
>>
>> #ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK
>> int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);
>> diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
>> index d76fd0840946..fbc938bd3b23 100644
>> --- a/fs/resctrl/monitor.c
>> +++ b/fs/resctrl/monitor.c
>> @@ -989,6 +989,14 @@ static int mbm_cntr_alloc(struct rdt_resource *r, struct rdt_mon_domain *d,
>> return -ENOSPC;
>> }
>>
>> +/*
>> + * mbm_cntr_free() - Reset cntr_id to zero.
>
> "Reset cntr_id to zero"? cntr_id is an index to an array.
> Please provide accurate and useful descriptions.
Yes. My bad. Will correct it.
>
>> + */
>> +static void mbm_cntr_free(struct rdt_mon_domain *d, int cntr_id)
>> +{
>> + memset(&d->cntr_cfg[cntr_id], 0, sizeof(struct mbm_cntr_cfg));
>> +}
>> +
>> /*
>> * mbm_get_mon_event() - Return the mon_evt entry for the matching evtid.
>> */
>> @@ -1068,3 +1076,55 @@ int resctrl_assign_cntr_event(struct rdt_resource *r, struct rdt_mon_domain *d,
>>
>> return ret;
>> }
>> +
>> +/*
>> + * Unassign and free the counter if assigned.
>> + */
>> +static int resctrl_free_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d,
>> + struct rdtgroup *rdtgrp, enum resctrl_event_id evtid)
>> +{
>> + struct mon_evt *mevt;
>> + 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 0;
>> +
>> + mevt = mbm_get_mon_event(r, evtid);
>> + if (!mevt) {
>> + rdt_last_cmd_printf("Invalid event id %d\n", evtid);
>
> Similar to previous comment this is in kernel bug territory and could be simplified
> by passing mon_evt instead. Although this is the unassign portion where
> evt_cfg seems unnecessary.
Sure. The call mbm_get_mon_event() is not required anymore in this path.
>
>> + return -EINVAL;
>> + }
>> +
>> + resctrl_config_cntr(r, d, evtid, rdtgrp->mon.rmid, rdtgrp->closid,
>> + cntr_id, mevt->evt_cfg, false);
>> +
>> + mbm_cntr_free(d, cntr_id);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * Unassign a hardware counter associated with @evtid from the domain and
>> + * the group. Unassign the counters from all the domains if @d is NULL else
>> + * unassign from @d.
>> + */
>> +int resctrl_unassign_cntr_event(struct rdt_resource *r, struct rdt_mon_domain *d,
>> + struct rdtgroup *rdtgrp, enum resctrl_event_id evtid)
>> +{
>> + int ret;
>> +
>> + if (!d) {
>> + list_for_each_entry(d, &r->mon_domains, hdr.list) {
>> + ret = resctrl_free_config_cntr(r, d, rdtgrp, evtid);
>> + if (ret)
>> + return ret;
>> + }
>> + } else {
>> + ret = resctrl_free_config_cntr(r, d, rdtgrp, evtid);
>> + }
>> +
>> + return ret;
>> +}
>
> Reinette
>
--
Thanks
Babu Moger
