Re: [PATCH 11/45] fs/proc: Enable smaps_pte_entry to handle cont-pte mapped hugetlb vmas

[David Hildenbrand <david@redhat.com>]

>   
>   #ifdef CONFIG_PGTABLE_HAS_HUGE_LEAVES
> @@ -952,6 +956,7 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
>   	struct vm_area_struct *vma = walk->vma;
>   	pte_t *pte;
>   	spinlock_t *ptl;
> +	unsigned long size, cont_ptes;
>   
>   	ptl = pmd_huge_lock(pmd, vma);
>   	if (ptl) {
> @@ -965,7 +970,9 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
>   		walk->action = ACTION_AGAIN;
>   		return 0;
>   	}
> -	for (; addr != end; pte++, addr += PAGE_SIZE)
> +	size = pte_cont(ptep_get(pte)) ? PAGE_SIZE * CONT_PTES : PAGE_SIZE;
> +	cont_ptes = pte_cont(ptep_get(pte)) ? CONT_PTES : 1;
> +	for (; addr != end; pte += cont_ptes, addr += size)

The better way to do this is to actually batch PTEs also when cont-pte 
is not around (e.g., x86). folio_pte_batch() does that and optimized 
automatically for the cont-pte bit -- which should only apply if we have 
a present folio.

So this code might need some slight reshuffling (lookup the folio first, 
if it's large use folio_pte_batch(), otherwise (small/no normal folio) 
process individual PTEs).

-- 
Cheers,

David / dhildenb