Re: [PATCH v7 06/12] x86/resctrl: Introduce data structure to support monitor configuration

Moger, Babu
2022-10-26T19:26:08Z

Hi Reinette,

On 10/25/22 18:45, Reinette Chatre wrote:
> Hi Babu,
>
> On 10/17/2022 3:26 PM, Babu Moger wrote:
>> Add a new field in mon_evt to support Bandwidth Monitoring Event
>> Configuration(BMEC) and also update the "mon_features" display.
>>
>> The sysfs file "mon_features" will display the monitor configuration
>> if supported.
>>
>> Before the change.
>> $cat /sys/fs/resctrl/info/L3_MON/mon_features
>> llc_occupancy
>> mbm_total_bytes
>> mbm_local_bytes
>>
>> After the change if BMEC is supported.
>> $cat /sys/fs/resctrl/info/L3_MON/mon_features
>> llc_occupancy
>> mbm_total_bytes
>> mbm_total_config
>> mbm_local_bytes
>> mbm_local_config
> This does not seem to be what the code in this patch does.

You are right. it is

# cat /sys/fs/resctrl/info/L3_MON/mon_features
llc_occupancy
mbm_total_bytes
mbm_total_bytes_config
mbm_local_bytes
mbm_local_bytes_config

>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>> arch/x86/kernel/cpu/resctrl/core.c | 3 ++-
>> arch/x86/kernel/cpu/resctrl/internal.h | 4 +++-
>> arch/x86/kernel/cpu/resctrl/monitor.c | 7 ++++++-
>> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 5 ++++-
>> 4 files changed, 15 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
>> index d79f494a4e91..46813b1c50c2 100644
>> --- a/arch/x86/kernel/cpu/resctrl/core.c
>> +++ b/arch/x86/kernel/cpu/resctrl/core.c
>> @@ -814,6 +814,7 @@ static __init bool get_rdt_alloc_resources(void)
>> static __init bool get_rdt_mon_resources(void)
>> {
>> struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
>> + bool mon_configurable = rdt_cpu_has(X86_FEATURE_BMEC);
>>
>> if (rdt_cpu_has(X86_FEATURE_CQM_OCCUP_LLC))
>> rdt_mon_features |= (1 << QOS_L3_OCCUP_EVENT_ID);
>> @@ -825,7 +826,7 @@ static __init bool get_rdt_mon_resources(void)
>> if (!rdt_mon_features)
>> return false;
>>
>> - return !rdt_get_mon_l3_config(r);
>> + return !rdt_get_mon_l3_config(r, mon_configurable);
>> }
> This seems to do a portion of configuration in the calling function, pass the
> results of to the actual configuration function where the rest of the configuration is
> done. Determining "mon_configurable" really looks like it belongs in
> rdt_get_mon_l3_config(). Is it availability of rdt_cpu_has() that prevented
> that change? Why not make it available internally to all resctrl code?

Yes. It is because of rdt_cpu_has availability. Also, it is __init routine.

Yes. I can make it available.

>
> Patch 7's mbm_config_rftype_init() can also be moved to rdt_get_mon_l3_config()
> to match how other related configs (thread_throttle_mode_init()) are done.
Sure. Will do.
>
>>
>> static __init void __check_quirks_intel(void)
>> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
>> index 16e3c6e03c79..b458f768f30c 100644
>> --- a/arch/x86/kernel/cpu/resctrl/internal.h
>> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
>> @@ -63,11 +63,13 @@ DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
>> * struct mon_evt - Entry in the event list of a resource
>> * @evtid: event id
>> * @name: name of the event
>> + * @configurable: true if the event is configurable
>> * @list: entry in &rdt_resource->evt_list
>> */
>> struct mon_evt {
>> enum resctrl_event_id evtid;
>> char *name;
>> + bool configurable;
>> struct list_head list;
>> };
>>
>> @@ -522,7 +524,7 @@ int closids_supported(void);
>> void closid_free(int closid);
>> int alloc_rmid(void);
>> void free_rmid(u32 rmid);
>> -int rdt_get_mon_l3_config(struct rdt_resource *r);
>> +int rdt_get_mon_l3_config(struct rdt_resource *r, bool configurable);
>> void mon_event_count(void *info);
>> int rdtgroup_mondata_show(struct seq_file *m, void *arg);
>> void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
>> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
>> index efe0c30d3a12..4b8adb7f1c5c 100644
>> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
>> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
>> @@ -746,7 +746,7 @@ static void l3_mon_evt_init(struct rdt_resource *r)
>> list_add_tail(&mbm_local_event.list, &r->evt_list);
>> }
>>
>> -int rdt_get_mon_l3_config(struct rdt_resource *r)
>> +int rdt_get_mon_l3_config(struct rdt_resource *r, bool configurable)
>> {
>> unsigned int mbm_offset = boot_cpu_data.x86_cache_mbm_width_offset;
>> struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
>> @@ -783,6 +783,11 @@ int rdt_get_mon_l3_config(struct rdt_resource *r)
>> if (ret)
>> return ret;
>>
>> + if (configurable) {
>> + mbm_total_event.configurable = true;
>> + mbm_local_event.configurable = true;
>> + }
>> +
>> l3_mon_evt_init(r);
>>
>> r->mon_capable = true;
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 1271fd1ae2f3..5f0ef1bf4c78 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -1001,8 +1001,11 @@ static int rdt_mon_features_show(struct kernfs_open_file *of,
>> struct rdt_resource *r = of->kn->parent->priv;
>> struct mon_evt *mevt;
>>
>> - list_for_each_entry(mevt, &r->evt_list, list)
>> + list_for_each_entry(mevt, &r->evt_list, list) {
>> seq_printf(seq, "%s\n", mevt->name);
>> + if (mevt->configurable)
>> + seq_printf(seq, "%s_config\n", mevt->name);
>> + }
>>
>> return 0;
>> }
>>
> If mevt->name is "mbm_total_bytes", then would this not
> print "mbm_total_bytes_config"? This is different from "mbm_total_config"
> in the changelog and does not match the actual files created in later
> patches..

Sure. Will update the changelog,

Thanks

Babu