Re: [PATCH 3/3] mm: don't remap clean subpages when splitting isolated thp

[Kirill A. Shutemov]

On Sat, Jul 31, 2021 at 12:39:38AM -0600, Yu Zhao wrote:
> @@ -267,13 +308,19 @@ static bool remove_migration_pte(struct page *page, struct vm_area_struct *vma,
>   * Get rid of all migration entries and replace them by
>   * references to the indicated page.
>   */
> -void remove_migration_ptes(struct page *old, struct page *new, bool locked)
> +void remove_migration_ptes(struct page *old, struct page *new, bool locked, bool unmap_clean)
>  {
> +	struct rmap_walk_arg rmap_walk_arg = {
> +		.page = old,
> +		.unmap_clean = unmap_clean,
> +	};
>  	struct rmap_walk_control rwc = {
>  		.rmap_one = remove_migration_pte,
> -		.arg = old,
> +		.arg = &rmap_walk_arg,
>  	};

'old' pointer has few low always-zero bit :P

-- 
 Kirill A. Shutemov