On Tue, 14 Jun 2016 17:17:37 +0800 <[email protected]> wrote:
> From: z00281421 <[email protected]>
>
> more mapcount page as kpage could reduce total replacement
> times than fewer mapcount one when ksmd scan and replace
> among forked pages later.
>
Hopefully Hugh will be able to have a think about this.
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -1094,6 +1094,21 @@ static struct page *try_to_merge_two_pages(struct
> rmap_item *rmap_item,
> {
> int err;
>
> + /*
> + * select more mapcount page as kpage
> + */
> + if (page_mapcount(page) < page_mapcount(tree_page)) {
> + struct page *tmp_page;
> + struct rmap_item *tmp_rmap_item;
> +
> + tmp_page = page;
> + page = tree_page;
> + tree_page = tmp_page;
> + tmp_rmap_item = rmap_item;
> + rmap_item = tree_rmap_item;
> + tree_rmap_item = tmp_rmap_item;
> + }
kernel.h provides a swap() macro.
> err = try_to_merge_with_ksm_page(rmap_item, page, NULL);
> if (!err) {
> err = try_to_merge_with_ksm_page(tree_rmap_item,
