Hi Tony,
On 10/11/24 16:33, Luck, Tony wrote:
>>>> +static int rdtgroup_assign_cntrs(struct rdtgroup *rdtgrp)
>>>> +{
>>>> + struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
>>>> + int ret = 0;
>>>> +
>>>> + if (!resctrl_arch_mbm_cntr_assign_enabled(r))
>>>> + return 0;
>>>> +
>>>> + if (is_mbm_total_enabled())
>>>> + ret = rdtgroup_assign_cntr_event(r, rdtgrp, NULL, QOS_L3_MBM_TOTAL_EVENT_ID);
>
> Consider that this call fails. "ret" indicates failure to allocate.
Look at this call
if (is_mbm_total_enabled())
ret = rdtgroup_assign_cntr_event(r, rdtgrp, NULL,
QOS_L3_MBM_TOTAL_EVENT_ID);
If this call fails, it will return immediately.
Lets say ret = 1; (1 if for failure. 0 for success)
>
>>>> +
>>>> + if (!ret && is_mbm_local_enabled())
>>>> + ret = rdtgroup_assign_cntr_event(r, rdtgrp, NULL, QOS_L3_MBM_LOCAL_EVENT_ID);
>
> Now this call succeeds. The failure of the previous call is forgotten as "ret" is
> overwritten with the success code.
It will not make this call if the first call fails because of this check.
if (!ret && is_mbm_local_enabled())
ret = rdtgroup_assign_cntr_event(r, rdtgrp, NULL,
QOS_L3_MBM_LOCAL_EVENT_ID);
return ret;
Here if (!1) evaluates to false.
Did I miss something?
>
>>>
>>> This overwrites the value from allocating the counter for total event.
>>
>> Total event and local events have two different indexes.
>> Can you please elaborate?
>
> See comments above. If you want a return code you need
>
> int ret_local = 0, ret_total = 0;
>
> if (is_mbm_total_enabled())
> ret_total = rdtgroup_assign_cntr_event(r, rdtgrp, NULL, QOS_L3_MBM_TOTAL_EVENT_ID);
> if (!ret && is_mbm_local_enabled())
> ret_local = rdtgroup_assign_cntr_event(r, rdtgrp, NULL, QOS_L3_MBM_LOCAL_EVENT_ID);
>
>
> return some_function of ret_local and ret_total;
>
> Not sure if you want to say success only if both of these calls succeeded. Or maybe if either worked?
>
> But it all seems complicated since callers don't have to take any different action depending on whether allocation of a counter succeeds or fails.
>
> -Tony
>
>
>
--
Thanks
Babu Moger
