Hi Babu,
On 1/22/25 12:20 PM, Babu Moger wrote:
> The event configuration is domain specific and initialized during domain
> initialization. The values are stored in struct rdt_hw_mon_domain.
>
> It is not required to read the configuration register every time user asks
> for it. Use the value stored in struct rdt_hw_mon_domain instead.
>
> Introduce resctrl_arch_mon_event_config_get() and
> resctrl_arch_mon_event_config_set() to get/set architecture domain specific
> mbm_total_cfg/mbm_local_cfg values.
>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
> ---
> arch/x86/kernel/cpu/resctrl/internal.h | 15 +++++++
> arch/x86/kernel/cpu/resctrl/monitor.c | 46 +++++++++++++++++++
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 61 +++++---------------------
> 3 files changed, 72 insertions(+), 50 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index ab28b9340ee7..cfaea20145d0 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -605,6 +605,18 @@ union cpuid_0x10_x_edx {
> unsigned int full;
> };
>
> +/**
> + * struct mon_config_info - Monitoring event configuratiin details
Same typo as previous version.
> + * @d: Domain for the event
> + * @evtid: Event type
> + * @mon_config: Event configuration value
> + */
> +struct mon_config_info {
> + struct rdt_mon_domain *d;
> + enum resctrl_event_id evtid;
> + u32 mon_config;
> +};
> +
> void rdt_last_cmd_clear(void);
> void rdt_last_cmd_puts(const char *s);
> __printf(1, 2)
> @@ -674,4 +686,7 @@ int resctrl_arch_mbm_cntr_assign_set(struct rdt_resource *r, bool enable);
> bool resctrl_arch_mbm_cntr_assign_enabled(struct rdt_resource *r);
> void arch_mbm_evt_config_init(struct rdt_hw_mon_domain *hw_dom);
> unsigned int mon_event_config_index_get(u32 evtid);
> +void resctrl_arch_mon_event_config_set(void *info);
> +u32 resctrl_arch_mon_event_config_get(struct rdt_mon_domain *d,
> + enum resctrl_event_id eventid);
> #endif /* _ASM_X86_RESCTRL_INTERNAL_H */
> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
> index 8917c7261680..6fe9e610e9a0 100644
> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
> @@ -1324,3 +1324,49 @@ int resctrl_arch_mbm_cntr_assign_set(struct rdt_resource *r, bool enable)
>
> return 0;
> }
> +
> +u32 resctrl_arch_mon_event_config_get(struct rdt_mon_domain *d,
> + enum resctrl_event_id eventid)
> +{
> + struct rdt_hw_mon_domain *hw_dom = resctrl_to_arch_mon_dom(d);
> +
> + switch (eventid) {
> + case QOS_L3_OCCUP_EVENT_ID:
> + break;
> + case QOS_L3_MBM_TOTAL_EVENT_ID:
> + return hw_dom->mbm_total_cfg;
> + case QOS_L3_MBM_LOCAL_EVENT_ID:
> + return hw_dom->mbm_local_cfg;
> + }
> +
> + /* Never expect to get here */
> + WARN_ON_ONCE(1);
> +
> + return INVALID_CONFIG_VALUE;
> +}
> +
> +void resctrl_arch_mon_event_config_set(void *info)
> +{
> + struct mon_config_info *mon_info = info;
> + struct rdt_hw_mon_domain *hw_dom;
> + unsigned int index;
> +
> + index = mon_event_config_index_get(mon_info->evtid);
> + if (index == INVALID_CONFIG_INDEX)
> + return;
> +
> + wrmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, 0);
> +
> + hw_dom = resctrl_to_arch_mon_dom(mon_info->d);
> +
> + switch (mon_info->evtid) {
> + case QOS_L3_MBM_TOTAL_EVENT_ID:
> + hw_dom->mbm_total_cfg = mon_info->mon_config;
> + break;
> + case QOS_L3_MBM_LOCAL_EVENT_ID:
> + hw_dom->mbm_local_cfg = mon_info->mon_config;
> + break;
> + default:
> + break;
> + }
> +}
This new arch API has sharp corners because of asymmetry of where resctrl
runs the arch function. I do not think it is required to change this since we
can only speculate about how this may be used in the future but I do think
it will be helpful to add comments that highlight:
resctrl_arch_mon_event_config_get() -> May run on CPU that does not belong to domain.
resctrl_arch_mon_event_config_set() -> Runs on CPU that belongs to domain.
...
> @@ -1683,33 +1653,23 @@ static int mbm_local_bytes_config_show(struct kernfs_open_file *of,
> return 0;
> }
>
> -static void mon_event_config_write(void *info)
> -{
> - struct mon_config_info *mon_info = info;
> - unsigned int index;
> -
> - index = mon_event_config_index_get(mon_info->evtid);
> - if (index == INVALID_CONFIG_INDEX) {
> - pr_warn_once("Invalid event id %d\n", mon_info->evtid);
> - return;
> - }
> - wrmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, 0);
> -}
>
> static void mbm_config_write_domain(struct rdt_resource *r,
> struct rdt_mon_domain *d, u32 evtid, u32 val)
> {
> struct mon_config_info mon_info = {0};
As discussed in previous version it is unnecessary to explicitly initialize
the structure if it is fully initialized in the code. This avoids need for
future cleanups like commit 29eaa7958367 ("x86/resctrl: Slightly clean-up mbm_config_show()")
Reinette
