mm/swap: Add folio_activate()

This replaces activate_page() and eliminates lots of calls to
compound_head().  Saves net 118 bytes of kernel text.  There are still
some redundant calls to page_folio() here which will be removed when
pagevec_lru_move_fn() is converted to use folios.
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>

include/trace/events/pagemap.h

@@ -60,23 +60,21 @@ TRACE_EVENT(mm_lru_insertion,
 
 TRACE_EVENT(mm_lru_activate,
 
-	TP_PROTO(struct page *page),
+	TP_PROTO(struct folio *folio),
 
-	TP_ARGS(page),
+	TP_ARGS(folio),
 
 	TP_STRUCT__entry(
-		__field(struct page *,	page	)
+		__field(struct folio *,	folio	)
 		__field(unsigned long,	pfn	)
 	),
 
 	TP_fast_assign(
-		__entry->page	= page;
-		__entry->pfn	= page_to_pfn(page);
+		__entry->folio	= folio;
+		__entry->pfn	= folio_pfn(folio);
 	),
 
-	/* Flag format is based on page-types.c formatting for pagemap */
-	TP_printk("page=%p pfn=0x%lx", __entry->page, __entry->pfn)
-
+	TP_printk("folio=%p pfn=0x%lx", __entry->folio, __entry->pfn)
 );
 
 #endif /* _TRACE_PAGEMAP_H */

mm/swap.c

@@ -300,15 +300,15 @@ void lru_note_cost_page(struct page *page)
 		      page_is_file_lru(page), thp_nr_pages(page));
 }
 
-static void __activate_page(struct page *page, struct lruvec *lruvec)
+static void __folio_activate(struct folio *folio, struct lruvec *lruvec)
 {
-	if (!PageActive(page) && !PageUnevictable(page)) {
-		int nr_pages = thp_nr_pages(page);
+	if (!folio_test_active(folio) && !folio_test_unevictable(folio)) {
+		long nr_pages = folio_nr_pages(folio);
 
-		del_page_from_lru_list(page, lruvec);
-		SetPageActive(page);
-		add_page_to_lru_list(page, lruvec);
-		trace_mm_lru_activate(page);
+		lruvec_del_folio(lruvec, folio);
+		folio_set_active(folio);
+		lruvec_add_folio(lruvec, folio);
+		trace_mm_lru_activate(folio);
 
 		__count_vm_events(PGACTIVATE, nr_pages);
 		__count_memcg_events(lruvec_memcg(lruvec), PGACTIVATE,
@@ -317,6 +317,11 @@ static void __activate_page(struct page *page, struct lruvec *lruvec)
 }
 
 #ifdef CONFIG_SMP
+static void __activate_page(struct page *page, struct lruvec *lruvec)
+{
+	return __folio_activate(page_folio(page), lruvec);
+}
+
 static void activate_page_drain(int cpu)
 {
 	struct pagevec *pvec = &per_cpu(lru_pvecs.activate_page, cpu);
@@ -330,16 +335,16 @@ static bool need_activate_page_drain(int cpu)
 	return pagevec_count(&per_cpu(lru_pvecs.activate_page, cpu)) != 0;
 }
 
-static void activate_page(struct page *page)
+static void folio_activate(struct folio *folio)
 {
-	page = compound_head(page);
-	if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
+	if (folio_test_lru(folio) && !folio_test_active(folio) &&
+	    !folio_test_unevictable(folio)) {
 		struct pagevec *pvec;
 
+		folio_get(folio);
 		local_lock(&lru_pvecs.lock);
 		pvec = this_cpu_ptr(&lru_pvecs.activate_page);
-		get_page(page);
-		if (pagevec_add_and_need_flush(pvec, page))
+		if (pagevec_add_and_need_flush(pvec, &folio->page))
 			pagevec_lru_move_fn(pvec, __activate_page);
 		local_unlock(&lru_pvecs.lock);
 	}
@@ -350,17 +355,15 @@ static inline void activate_page_drain(int cpu)
 {
 }
 
-static void activate_page(struct page *page)
+static void folio_activate(struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
 	struct lruvec *lruvec;
 
-	page = &folio->page;
-	if (TestClearPageLRU(page)) {
+	if (folio_test_clear_lru(folio)) {
 		lruvec = folio_lruvec_lock_irq(folio);
-		__activate_page(page, lruvec);
+		__folio_activate(folio, lruvec);
 		unlock_page_lruvec_irq(lruvec);
-		SetPageLRU(page);
+		folio_set_lru(folio);
 	}
 }
 #endif
@@ -425,7 +428,7 @@ void mark_page_accessed(struct page *page)
 		 * LRU on the next drain.
 		 */
 		if (PageLRU(page))
-			activate_page(page);
+			folio_activate(page_folio(page));
 		else
 			__lru_cache_activate_page(page);
 		ClearPageReferenced(page);