Hi Babu,
On 8/26/2022 9:07 AM, Moger, Babu wrote:
> On 8/24/22 16:15, Reinette Chatre wrote:
>> On 8/22/2022 6:43 AM, Babu Moger wrote:
...
>>> static int mkdir_mondata_subdir(struct kernfs_node *parent_kn,
>>> struct rdt_domain *d,
>>> struct rdt_resource *r, struct rdtgroup *prgrp)
>>> @@ -2568,6 +2591,15 @@ static int mkdir_mondata_subdir(struct kernfs_node *parent_kn,
>>> if (ret)
>>> goto out_destroy;
>>>
>>> + /* Create the sysfs event configuration files */
>>> + if (r->mon_configurable &&
>>> + (mevt->evtid == QOS_L3_MBM_TOTAL_EVENT_ID ||
>>> + mevt->evtid == QOS_L3_MBM_LOCAL_EVENT_ID)) {
>>> + ret = mon_config_addfile(kn, mevt->config, priv.priv);
>>> + if (ret)
>>> + goto out_destroy;
>>> + }
>>> +
>> This seems complex to have event features embedded in the code in this way. Could
>> the events not be configured during system enumeration? For example, instead
>> of hardcoding the config like above to always set:
>>
>> static struct mon_evt mbm_local_event = {
>> .name = "mbm_local_bytes",
>> .evtid = QOS_L3_MBM_LOCAL_EVENT_ID,
>> + .config = "mbm_local_config",
>>
>>
>> What if instead this information is dynamically set in rdt_get_mon_l3_config()? To
>> make things simpler struct mon_evt could get a new member "configurable" and the
>> events that actually support configuration will have this set only
>> if system has X86_FEATURE_BMEC (struct rdt_resource->configurable then
>> becomes unnecessary?). Being configurable thus becomes an event property, not
>> a resource property. The "config" member introduced here could then be "config_name".
>>
>> I think doing so will also make this file creation simpler with a single
>> mon_config_addfile() (possibly with more parameters) used to add both files to
>> avoid the code duplication introduced by mon_config_addfile() above.
>>
>> What do you think?
>
> Yes. We could do that. Something like this.
>
> struct mon_evt {
> u32 evtid;
> char *name;
>
> + bool configurable;
>
> char *config;
> struct list_head list;
> };
>
> Set the configurable if the system has X86_FEATURE_BMEC feature in
> rdt_get_mon_l3_config.
This would work (using bool in struct is something resctrl already do
in many places). I also think that "config" should rather be named to
"config_name" to make clear that it is not the actual configuration of
the event.
Remember to update struct mon_evt's kerneldoc (I just noticed it is
missing from this series).
>
> Create both files mbm_local_bytes and mbm_local_config in mon_addfile.
>
> Change the mon_addfile to pass mon_evt structure, so it have all
> information to create both the files.
Providing the structure to the function would make all the information
available but I am not sure that doing so would make it easy to eliminate the
duplicate code needed to create the other file. Giving more parameters
to mon_addfile() is another option but it should be more clear to
you as you write this code.
>
> Then we can remove rdt_resource->configurable.
>
> Does that make sense?
>
Yes.
Reinette
