Commit 9d5cc140 authored by Alex Shi (tencent)'s avatar Alex Shi (tencent) Committed by Andrew Morton
Browse files

mm/ksm: use folio in remove_stable_node 

Pages in stable tree are all single normal page, so uses ksm_get_folio()
and folio_set_stable_node(), also saves 3 calls to compound_head().

Link: https://lkml.kernel.org/r/20240411061713.1847574-5-alexs@kernel.org


Signed-off-by: default avatarAlex Shi (tencent) <alexs@kernel.org>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Izik Eidus <izik.eidus@ravellosystems.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b8b0ff24

mm/ksm.c

+12 −12
Original line number Diff line number Diff line
@@ -1121,13 +1121,13 @@ static inline void folio_set_stable_node(struct folio *folio, 
 */

static int remove_stable_node(struct ksm_stable_node *stable_node)

{

	struct page *page;

	struct folio *folio;

	int err;



	page = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK);

	if (!page) {

	folio = ksm_get_folio(stable_node, GET_KSM_PAGE_LOCK);

	if (!folio) {

		/*

		 * get_ksm_page did remove_node_from_stable_tree itself.

		 * ksm_get_folio did remove_node_from_stable_tree itself.

		 */

		return 0;

	}
@@ -1138,22 +1138,22 @@ static int remove_stable_node(struct ksm_stable_node *stable_node) 
	 * merge_across_nodes/max_page_sharing be switched.

	 */

	err = -EBUSY;

	if (!page_mapped(page)) {

	if (!folio_mapped(folio)) {

		/*

		 * The stable node did not yet appear stale to get_ksm_page(),

		 * since that allows for an unmapped ksm page to be recognized

		 * The stable node did not yet appear stale to ksm_get_folio(),

		 * since that allows for an unmapped ksm folio to be recognized

		 * right up until it is freed; but the node is safe to remove.

		 * This page might be in an LRU cache waiting to be freed,

		 * or it might be PageSwapCache (perhaps under writeback),

		 * This folio might be in an LRU cache waiting to be freed,

		 * or it might be in the swapcache (perhaps under writeback),

		 * or it might have been removed from swapcache a moment ago.

		 */

		set_page_stable_node(page, NULL);

		folio_set_stable_node(folio, NULL);

		remove_node_from_stable_tree(stable_node);

		err = 0;

	}



	unlock_page(page);

	put_page(page);

	folio_unlock(folio);

	folio_put(folio);

	return err;

}