Re: [RFC PATCH 05/12] khugepaged: Generalize __collapse_huge_page_isolate()

[Matthew Wilcox]

On Mon, Dec 16, 2024 at 10:20:58PM +0530, Dev Jain wrote:
>  {
> -	struct page *page = NULL;
> -	struct folio *folio = NULL;
> -	pte_t *_pte;
> +	unsigned int max_ptes_shared = khugepaged_max_ptes_shared >> (HPAGE_PMD_ORDER - order);
> +	unsigned int max_ptes_none = khugepaged_max_ptes_none >> (HPAGE_PMD_ORDER - order);
>  	int none_or_zero = 0, shared = 0, result = SCAN_FAIL, referenced = 0;
> +	struct folio *folio = NULL;
> +	struct page *page = NULL;

why are you moving variables around unnecessarily?

>  	bool writable = false;
> +	pte_t *_pte;
>  
> -	for (_pte = pte; _pte < pte + HPAGE_PMD_NR;
> +
> +	for (_pte = pte; _pte < pte + (1UL << order);

spurious blank line


also you might first want to finish off the page->folio conversion in
this function first; we have a vm_normal_folio() now.