[PATCH v2 09/14] mm/ksm: Convert stable_tree_insert to use folio

[alexs@xxxxxxxxxx]

From: "Alex Shi (tencent)" <alexs@xxxxxxxxxx>

KSM stable tree only store single page, so convert the func users to use
folio and save few compound_head calls.

Signed-off-by: Alex Shi (tencent) <alexs@xxxxxxxxxx>
Cc: Izik Eidus <izik.eidus@xxxxxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Chris Wright <chrisw@xxxxxxxxxxxx>
---
 mm/ksm.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 30570e1f68ec..e6837e615ef0 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -2078,7 +2078,7 @@ static struct page *stable_tree_search(struct page *page)
  * This function returns the stable tree node just allocated on success,
  * NULL otherwise.
  */
-static struct ksm_stable_node *stable_tree_insert(struct page *kpage)
+static struct ksm_stable_node *stable_tree_insert(struct folio *kfolio)
 {
 	int nid;
 	unsigned long kpfn;
@@ -2088,7 +2088,7 @@ static struct ksm_stable_node *stable_tree_insert(struct page *kpage)
 	struct ksm_stable_node *stable_node, *stable_node_dup, *stable_node_any;
 	bool need_chain = false;
 
-	kpfn = page_to_pfn(kpage);
+	kpfn = folio_pfn(kfolio);
 	nid = get_kpfn_nid(kpfn);
 	root = root_stable_tree + nid;
 again:
@@ -2096,13 +2096,13 @@ static struct ksm_stable_node *stable_tree_insert(struct page *kpage)
 	new = &root->rb_node;
 
 	while (*new) {
-		struct page *tree_page;
+		struct folio *tree_folio;
 		int ret;
 
 		cond_resched();
 		stable_node = rb_entry(*new, struct ksm_stable_node, node);
 		stable_node_any = NULL;
-		tree_page = chain(&stable_node_dup, stable_node, root);
+		tree_folio = chain(&stable_node_dup, stable_node, root);
 		if (!stable_node_dup) {
 			/*
 			 * Either all stable_node dups were full in
@@ -2124,11 +2124,11 @@ static struct ksm_stable_node *stable_tree_insert(struct page *kpage)
 			 * write protected at all times. Any will work
 			 * fine to continue the walk.
 			 */
-			tree_page = get_ksm_page(stable_node_any,
-						 GET_KSM_PAGE_NOLOCK);
+			tree_folio = ksm_get_folio(stable_node_any,
+						   GET_KSM_PAGE_NOLOCK);
 		}
 		VM_BUG_ON(!stable_node_dup ^ !!stable_node_any);
-		if (!tree_page) {
+		if (!tree_folio) {
 			/*
 			 * If we walked over a stale stable_node,
 			 * get_ksm_page() will call rb_erase() and it
@@ -2141,8 +2141,8 @@ static struct ksm_stable_node *stable_tree_insert(struct page *kpage)
 			goto again;
 		}
 
-		ret = memcmp_pages(kpage, tree_page);
-		put_page(tree_page);
+		ret = memcmp_pages(&kfolio->page, &tree_folio->page);
+		folio_put(tree_folio);
 
 		parent = *new;
 		if (ret < 0)
@@ -2161,7 +2161,7 @@ static struct ksm_stable_node *stable_tree_insert(struct page *kpage)
 
 	INIT_HLIST_HEAD(&stable_node_dup->hlist);
 	stable_node_dup->kpfn = kpfn;
-	set_page_stable_node(kpage, stable_node_dup);
+	folio_set_stable_node(kfolio, stable_node_dup);
 	stable_node_dup->rmap_hlist_len = 0;
 	DO_NUMA(stable_node_dup->nid = nid);
 	if (!need_chain) {
@@ -2439,7 +2439,7 @@ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_ite
 			 * node in the stable tree and add both rmap_items.
 			 */
 			lock_page(kpage);
-			stable_node = stable_tree_insert(kpage);
+			stable_node = stable_tree_insert(page_folio(kpage));
 			if (stable_node) {
 				stable_tree_append(tree_rmap_item, stable_node,
 						   false);
-- 
2.43.0