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

This removes an assumption that THPs are the only kind of compound
pages and removes a few hidden calls to compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

include/linux/swap.h

@@ -328,7 +328,7 @@ static inline swp_entry_t folio_swap_entry(struct folio *folio)
 
 /* linux/mm/workingset.c */
 void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages);
-void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg);
+void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg);
 void workingset_refault(struct folio *folio, void *shadow);
 void workingset_activation(struct folio *folio);
 

mm/vmscan.c

@@ -1242,6 +1242,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping)
 static int __remove_mapping(struct address_space *mapping, struct page *page,
 			    bool reclaimed, struct mem_cgroup *target_memcg)
 {
+	struct folio *folio = page_folio(page);
 	int refcount;
 	void *shadow = NULL;
 
@@ -1289,7 +1290,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
 		swp_entry_t swap = { .val = page_private(page) };
 		mem_cgroup_swapout(page, swap);
 		if (reclaimed && !mapping_exiting(mapping))
-			shadow = workingset_eviction(page, target_memcg);
+			shadow = workingset_eviction(folio, target_memcg);
 		__delete_from_swap_cache(page, swap, shadow);
 		xa_unlock_irq(&mapping->i_pages);
 		put_swap_page(page, swap);
@@ -1315,8 +1316,8 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
 		 */
 		if (reclaimed && page_is_file_lru(page) &&
 		    !mapping_exiting(mapping) && !dax_mapping(mapping))
-			shadow = workingset_eviction(page, target_memcg);
-		__delete_from_page_cache(page, shadow);
+			shadow = workingset_eviction(folio, target_memcg);
+		__filemap_remove_folio(folio, shadow);
 		xa_unlock_irq(&mapping->i_pages);
 		if (mapping_shrinkable(mapping))
 			inode_add_lru(mapping->host);

mm/workingset.c

@@ -245,31 +245,32 @@ void workingset_age_nonresident(struct lruvec *lruvec, unsigned long nr_pages)
 }
 
 /**
- * workingset_eviction - note the eviction of a page from memory
+ * workingset_eviction - note the eviction of a folio from memory
  * @target_memcg: the cgroup that is causing the reclaim
- * @page: the page being evicted
+ * @folio: the folio being evicted
  *
- * Return: a shadow entry to be stored in @page->mapping->i_pages in place
- * of the evicted @page so that a later refault can be detected.
+ * Return: a shadow entry to be stored in @folio->mapping->i_pages in place
+ * of the evicted @folio so that a later refault can be detected.
  */
-void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg)
+void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg)
 {
-	struct pglist_data *pgdat = page_pgdat(page);
+	struct pglist_data *pgdat = folio_pgdat(folio);
 	unsigned long eviction;
 	struct lruvec *lruvec;
 	int memcgid;
 
-	/* Page is fully exclusive and pins page's memory cgroup pointer */
-	VM_BUG_ON_PAGE(PageLRU(page), page);
-	VM_BUG_ON_PAGE(page_count(page), page);
-	VM_BUG_ON_PAGE(!PageLocked(page), page);
+	/* Folio is fully exclusive and pins folio's memory cgroup pointer */
+	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
+	VM_BUG_ON_FOLIO(folio_ref_count(folio), folio);
+	VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
 
 	lruvec = mem_cgroup_lruvec(target_memcg, pgdat);
 	/* XXX: target_memcg can be NULL, go through lruvec */
 	memcgid = mem_cgroup_id(lruvec_memcg(lruvec));
 	eviction = atomic_long_read(&lruvec->nonresident_age);
-	workingset_age_nonresident(lruvec, thp_nr_pages(page));
-	return pack_shadow(memcgid, pgdat, eviction, PageWorkingset(page));
+	workingset_age_nonresident(lruvec, folio_nr_pages(folio));
+	return pack_shadow(memcgid, pgdat, eviction,
+				folio_test_workingset(folio));
 }
 
 /**