[PATCH] powerpc/mce: Remove per cpu variables from MCE handlers

[Mahesh Jagannath Salgaonkar]

On 12/8/20 4:16 PM, Ganesh wrote:
> 
> On 12/8/20 4:01 PM, Michael Ellerman wrote:
>> Ganesh Goudar <ganeshgr at linux.ibm.com> writes:
>>> diff --git a/arch/powerpc/include/asm/paca.h
>>> b/arch/powerpc/include/asm/paca.h
>>> index 9454d29ff4b4..4769954efa7d 100644
>>> --- a/arch/powerpc/include/asm/paca.h
>>> +++ b/arch/powerpc/include/asm/paca.h
>>> @@ -273,6 +274,17 @@ struct paca_struct {
>>>   #ifdef CONFIG_MMIOWB
>>>       struct mmiowb_state mmiowb_state;
>>>   #endif
>>> +#ifdef CONFIG_PPC_BOOK3S_64
>>> +    int mce_nest_count;
>>> +    struct machine_check_event mce_event[MAX_MC_EVT];
>>> +    /* Queue for delayed MCE events. */
>>> +    int mce_queue_count;
>>> +    struct machine_check_event mce_event_queue[MAX_MC_EVT];
>>> +
>>> +    /* Queue for delayed MCE UE events. */
>>> +    int mce_ue_count;
>>> +    struct machine_check_event  mce_ue_event_queue[MAX_MC_EVT];
>>> +#endif /* CONFIG_PPC_BOOK3S_64 */
>>>   } ____cacheline_aligned;
>> How much does this expand the paca by?
> 
> Size of paca is 4480 bytes, these add up another 2160 bytes, so expands
> it by 48%.
> 

Should we dynamically allocate the array sizes early as similar to that
of paca->mce_faulty_slbs so that we don't bump up paca size ?

Thanks,
-Mahesh.