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SubjectRe: [PATCH v8 10/13] x86/resctrl: Add sysfs interface to write mbm_total_bytes_config
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Hi Peter,

On 11/7/22 04:21, Peter Newman wrote:
> Hi Babu,
>
> On Fri, Nov 04, 2022 at 03:01:09PM -0500, Babu Moger wrote:
>> + /*
>> + * When an Event Configuration is changed, the bandwidth counters
>> + * for all RMIDs and Events will be cleared by the hardware. The
>> + * hardware also sets MSR_IA32_QM_CTR.Unavailable (bit 62) for
>> + * every RMID on the next read to any event for every RMID.
>> + * Subsequent reads will have MSR_IA32_QM_CTR.Unavailable (bit 62)
>> + * cleared while it is tracked by the hardware. Clear the
>> + * mbm_local and mbm_total counts for all the RMIDs.
>> + */
>> + memset(d->mbm_local, 0, sizeof(struct mbm_state) * r->num_rmid);
>> + memset(d->mbm_total, 0, sizeof(struct mbm_state) * r->num_rmid);
> Looking around, I can't find a reader for mbm_total anymore. It looks
> like the last place it was used went away in James's recent change:
>
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fall%2F20220902154829.30399-19-james.morse%40arm.com&data=05%7C01%7Cbabu.moger%40amd.com%7C84a9d0f934894a3031a608dac0a9db33%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638034133003350939%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=i3isjCzxnBp4b2VblC7ZpH3hShUEe7unKiKfngG1kzE%3D&reserved=0
>
> Are we supposed to be clearing arch_mbm_total now?

Yes. You are right. We should be using resctrl_arch_reset_rmid to reset
the rmids here.

This patch should work. Will fix it in next revision after the other comments.

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
b/arch/x86/kernel/cpu/resctrl/rdtgroup.c             │
index 6b222f8e58ae..28d9d99a639e
100644                                                                  │
---
a/arch/x86/kernel/cpu/resctrl/rdtgroup.c                                                            

+++
b/arch/x86/kernel/cpu/resctrl/rdtgroup.c                                                            

@@ -1517,7 +1517,7 @@ static int mbm_config_write(struct rdt_resource *r,
struct rdt_domain *d,          │
                            u32 evtid, u32
val)                                                          │
 {                                                                                                      

        struct mon_config_info mon_info =
{0};                                                           │
-       int ret =
0;                                                                                    

+       int ret = 0,
i;                                                                                 

                                                                                                        

       
rdt_last_cmd_clear();                                                                           

                                                                                                        

@@ -1557,8 +1557,10 @@ static int mbm_config_write(struct rdt_resource *r,
struct rdt_domain *d,         │
         * cleared while it is tracked by the hardware. Clear
the                                        │
         * mbm_local and mbm_total counts for all the
RMIDs.                                             │
        
*/                                                                                             

-       memset(d->mbm_local, 0, sizeof(struct mbm_state) *
r->num_rmid);                                 │
-       memset(d->mbm_total, 0, sizeof(struct mbm_state) *
r->num_rmid);                                 │
+       for (i = 0; i < r->num_rmid; i++)
{                                                              │
+               resctrl_arch_reset_rmid(r, d, i,
QOS_L3_MBM_TOTAL_EVENT_ID);                             │
+               resctrl_arch_reset_rmid(r, d, i,
QOS_L3_MBM_LOCAL_EVENT_ID);                             │
+      
}                                                                                               

                                                                                                        

 write_exit:                                                                                            

        return ret;                                   


Thanks

Babu

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