Re: [PATCH] mm: update comments for struct page.mapping

[Andrew Morton]

On Tue, 26 Sep 2017 15:14:17 +0800 changbin.du@xxxxxxxxx wrote:

> From: Changbin Du <changbin.du@xxxxxxxxx>
> 
> The struct page.mapping can NULL or points to one object of type
> address_space, anon_vma or KSM private structure.
> 
> ...
>
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -47,8 +47,8 @@ struct page {
>  						 * inode address_space, or NULL.
>  						 * If page mapped as anonymous
>  						 * memory, low bit is set, and
> -						 * it points to anon_vma object:
> -						 * see PAGE_MAPPING_ANON below.
> +						 * it points to anon_vma object
> +						 * or KSM private structure.
>  						 */
>  		void *s_mem;			/* slab first object */
>  		atomic_t compound_mapcount;	/* first tail page */

Why did you remove the (useful) reference to PAGE_MAPPING_ANON?