Re: [RFC PATCH v2 03/30] mm: thp: use single linked list for THP page table page deposit.

[Matthew Wilcox]

On Mon, Sep 28, 2020 at 01:54:01PM -0400, Zi Yan wrote:
>  		struct {	/* Page table pages */
> -			unsigned long _pt_pad_1;	/* compound_head */
> -			pgtable_t pmd_huge_pte; /* protected by page->ptl */
> +			struct llist_head deposit_head; /* pgtable deposit list head */
> +			struct llist_node deposit_node; /* pgtable deposit list node */

If you're going to use two pointers anyway, you might as well use a
list_head.  But I don't think you need to; you could either use a union
of these or you could use the page_address() of the page to store as
much information as you like!