Re: [PATCH v4 4/4] mm: huge_memory: use folio_needs_prot_numa() for pmd folio

[David Hildenbrand <david@redhat.com>]

>>   		/*
>>   		 * Avoid trapping faults against the zero page. The read-only
>>   		 * data is likely to be read-cached on the local CPU and
>> @@ -2490,19 +2490,13 @@ int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
>>   		if (pmd_protnone(*pmd))
>>   			goto unlock;
>>
>> -		folio = pmd_folio(*pmd);
>> -		toptier = node_is_toptier(folio_nid(folio));
>> -		/*
>> -		 * Skip scanning top tier node if normal numa
>> -		 * balancing is disabled
>> -		 */
>> -		if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) &&
>> -		    toptier)
>> -			goto unlock;
>> +		/* Get target node for single threaded private VMAs */
>> +		if (!(vma->vm_flags & VM_SHARED) &&
>> +		    atomic_read(&vma->vm_mm->mm_users) == 1)
>> +			target_node = numa_node_id();
> 
> This is duplicated in both callers, and only used by folio_needs_prot_numa(),
> why not abstract this to the function also?

There was a discussion on that in v3 I think where I asked the same 
question.

-- 
Cheers

David / dhildenb