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: Alex Shi (tencent) <alexs@kernel.org>
Reviewed-by: David 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: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/ksm.c b/mm/ksm.c
index 3c52bf9df84c8de099abc5d05f9f90373083e070..1a7b130045898d448b7b8bc952529148c56c3572 100644 (file)
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -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;
 }