mm/workingset: Convert workingset_refault() to take a folio

This nets us 178 bytes of savings from removing calls to compound_head.
The three callers all grow a little, but each of them will be converted
to use folios soon, so that's fine.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
diff --git a/mm/workingset.c b/mm/workingset.c
index 1c96ed5..109ab97 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -273,17 +273,17 @@ void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg)
 }
 
 /**
- * workingset_refault - evaluate the refault of a previously evicted page
- * @page: the freshly allocated replacement page
- * @shadow: shadow entry of the evicted page
+ * workingset_refault - Evaluate the refault of a previously evicted folio.
+ * @folio: The freshly allocated replacement folio.
+ * @shadow: Shadow entry of the evicted folio.
  *
  * Calculates and evaluates the refault distance of the previously
- * evicted page in the context of the node and the memcg whose memory
+ * evicted folio in the context of the node and the memcg whose memory
  * pressure caused the eviction.
  */
-void workingset_refault(struct page *page, void *shadow)
+void workingset_refault(struct folio *folio, void *shadow)
 {
-	bool file = page_is_file_lru(page);
+	bool file = folio_is_file_lru(folio);
 	struct mem_cgroup *eviction_memcg;
 	struct lruvec *eviction_lruvec;
 	unsigned long refault_distance;
@@ -295,16 +295,17 @@ void workingset_refault(struct page *page, void *shadow)
 	unsigned long refault;
 	bool workingset;
 	int memcgid;
+	long nr;
 
 	unpack_shadow(shadow, &memcgid, &pgdat, &eviction, &workingset);
 
 	rcu_read_lock();
 	/*
 	 * Look up the memcg associated with the stored ID. It might
-	 * have been deleted since the page's eviction.
+	 * have been deleted since the folio's eviction.
 	 *
 	 * Note that in rare events the ID could have been recycled
-	 * for a new cgroup that refaults a shared page. This is
+	 * for a new cgroup that refaults a shared folio. This is
 	 * impossible to tell from the available data. However, this
 	 * should be a rare and limited disturbance, and activations
 	 * are always speculative anyway. Ultimately, it's the aging
@@ -340,17 +341,18 @@ void workingset_refault(struct page *page, void *shadow)
 	refault_distance = (refault - eviction) & EVICTION_MASK;
 
 	/*
-	 * The activation decision for this page is made at the level
+	 * The activation decision for this folio is made at the level
 	 * where the eviction occurred, as that is where the LRU order
-	 * during page reclaim is being determined.
+	 * during folio reclaim is being determined.
 	 *
-	 * However, the cgroup that will own the page is the one that
+	 * However, the cgroup that will own the folio is the one that
 	 * is actually experiencing the refault event.
 	 */
-	memcg = page_memcg(page);
+	nr = folio_nr_pages(folio);
+	memcg = folio_memcg(folio);
 	lruvec = mem_cgroup_lruvec(memcg, pgdat);
 
-	inc_lruvec_state(lruvec, WORKINGSET_REFAULT_BASE + file);
+	mod_lruvec_state(lruvec, WORKINGSET_REFAULT_BASE + file, nr);
 
 	mem_cgroup_flush_stats();
 	/*
@@ -376,16 +378,16 @@ void workingset_refault(struct page *page, void *shadow)
 	if (refault_distance > workingset_size)
 		goto out;
 
-	SetPageActive(page);
-	workingset_age_nonresident(lruvec, thp_nr_pages(page));
-	inc_lruvec_state(lruvec, WORKINGSET_ACTIVATE_BASE + file);
+	folio_set_active(folio);
+	workingset_age_nonresident(lruvec, nr);
+	mod_lruvec_state(lruvec, WORKINGSET_ACTIVATE_BASE + file, nr);
 
-	/* Page was active prior to eviction */
+	/* Folio was active prior to eviction */
 	if (workingset) {
-		SetPageWorkingset(page);
+		folio_set_workingset(folio);
 		/* XXX: Move to lru_cache_add() when it supports new vs putback */
-		lru_note_cost_page(page);
-		inc_lruvec_state(lruvec, WORKINGSET_RESTORE_BASE + file);
+		lru_note_cost_folio(folio);
+		mod_lruvec_state(lruvec, WORKINGSET_RESTORE_BASE + file, nr);
 	}
 out:
 	rcu_read_unlock();