mm: make per-memcg LRU lists exclusive

Now that all code that operated on global per-zone LRU lists is
converted to operate on per-memory cgroup LRU lists instead, there is no
reason to keep the double-LRU scheme around any longer.

The pc->lru member is removed and page->lru is linked directly to the
per-memory cgroup LRU lists, which removes two pointers from a
descriptor that exists for every page frame in the system.

Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Ying Han <yinghan@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/memcontrol.h

@@ -32,14 +32,6 @@ enum mem_cgroup_page_stat_item {
 	MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
 };
 
-extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
-					struct list_head *dst,
-					unsigned long *scanned, int order,
-					isolate_mode_t mode,
-					struct zone *z,
-					struct mem_cgroup *mem_cont,
-					int active, int file);
-
 struct mem_cgroup_reclaim_cookie {
 	struct zone *zone;
 	int priority;
@@ -69,13 +61,14 @@ extern void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *ptr);
 
 extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
 					gfp_t gfp_mask);
-extern void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru);
-extern void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru);
-extern void mem_cgroup_rotate_reclaimable_page(struct page *page);
-extern void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru);
-extern void mem_cgroup_del_lru(struct page *page);
-extern void mem_cgroup_move_lists(struct page *page,
-				  enum lru_list from, enum lru_list to);
+
+struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *);
+struct lruvec *mem_cgroup_lru_add_list(struct zone *, struct page *,
+				       enum lru_list);
+void mem_cgroup_lru_del_list(struct page *, enum lru_list);
+void mem_cgroup_lru_del(struct page *);
+struct lruvec *mem_cgroup_lru_move_lists(struct zone *, struct page *,
+					 enum lru_list, enum lru_list);
 
 /* For coalescing uncharge for reducing memcg' overhead*/
 extern void mem_cgroup_uncharge_start(void);
@@ -223,33 +216,33 @@ static inline void mem_cgroup_uncharge_cache_page(struct page *page)
 {
 }
 
-static inline void mem_cgroup_add_lru_list(struct page *page, int lru)
-{
-}
-
-static inline void mem_cgroup_del_lru_list(struct page *page, int lru)
+static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
+						    struct mem_cgroup *memcg)
 {
-	return ;
+	return &zone->lruvec;
 }
 
-static inline void mem_cgroup_rotate_reclaimable_page(struct page *page)
+static inline struct lruvec *mem_cgroup_lru_add_list(struct zone *zone,
+						     struct page *page,
+						     enum lru_list lru)
 {
-	return ;
+	return &zone->lruvec;
 }
 
-static inline void mem_cgroup_rotate_lru_list(struct page *page, int lru)
+static inline void mem_cgroup_lru_del_list(struct page *page, enum lru_list lru)
 {
-	return ;
 }
 
-static inline void mem_cgroup_del_lru(struct page *page)
+static inline void mem_cgroup_lru_del(struct page *page)
 {
-	return ;
 }
 
-static inline void
-mem_cgroup_move_lists(struct page *page, enum lru_list from, enum lru_list to)
+static inline struct lruvec *mem_cgroup_lru_move_lists(struct zone *zone,
+						       struct page *page,
+						       enum lru_list from,
+						       enum lru_list to)
 {
+	return &zone->lruvec;
 }
 
 static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)

include/linux/mm_inline.h

@@ -21,27 +21,22 @@ static inline int page_is_file_cache(struct page *page)
 	return !PageSwapBacked(page);
 }
 
-static inline void
-__add_page_to_lru_list(struct zone *zone, struct page *page, enum lru_list l,
-		       struct list_head *head)
-{
-	list_add(&page->lru, head);
-	__mod_zone_page_state(zone, NR_LRU_BASE + l, hpage_nr_pages(page));
-	mem_cgroup_add_lru_list(page, l);
-}
-
 static inline void
 add_page_to_lru_list(struct zone *zone, struct page *page, enum lru_list l)
 {
-	__add_page_to_lru_list(zone, page, l, &zone->lruvec.lists[l]);
+	struct lruvec *lruvec;
+
+	lruvec = mem_cgroup_lru_add_list(zone, page, l);
+	list_add(&page->lru, &lruvec->lists[l]);
+	__mod_zone_page_state(zone, NR_LRU_BASE + l, hpage_nr_pages(page));
 }
 
 static inline void
 del_page_from_lru_list(struct zone *zone, struct page *page, enum lru_list l)
 {
+	mem_cgroup_lru_del_list(page, l);
 	list_del(&page->lru);
 	__mod_zone_page_state(zone, NR_LRU_BASE + l, -hpage_nr_pages(page));
-	mem_cgroup_del_lru_list(page, l);
 }
 
 /**
@@ -64,7 +59,6 @@ del_page_from_lru(struct zone *zone, struct page *page)
 {
 	enum lru_list l;
 
-	list_del(&page->lru);
 	if (PageUnevictable(page)) {
 		__ClearPageUnevictable(page);
 		l = LRU_UNEVICTABLE;
@@ -75,8 +69,9 @@ del_page_from_lru(struct zone *zone, struct page *page)
 			l += LRU_ACTIVE;
 		}
 	}
+	mem_cgroup_lru_del_list(page, l);
+	list_del(&page->lru);
 	__mod_zone_page_state(zone, NR_LRU_BASE + l, -hpage_nr_pages(page));
-	mem_cgroup_del_lru_list(page, l);
 }
 
 /**

include/linux/page_cgroup.h

@@ -31,7 +31,6 @@ enum {
 struct page_cgroup {
 	unsigned long flags;
 	struct mem_cgroup *mem_cgroup;
-	struct list_head lru;		/* per cgroup LRU list */
 };
 
 void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat);