mm: collect LRU list heads into struct lruvec

Having a unified structure with a LRU list set for both global zones and
per-memcg zones allows to keep that code simple which deals with LRU
lists and does not care about the container itself.

Once the per-memcg LRU lists directly link struct pages, the isolation
function and all other list manipulations are shared between the memcg
case and the global LRU case.

Signed-off-by: Johannes Weiner <jweiner@redhat.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: Ying Han <yinghan@google.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>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index ca6ca92418a6..42e544cd4c9f 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -159,6 +159,10 @@ static inline int is_unevictable_lru(enum lru_list l)
         return (l == LRU_UNEVICTABLE);
 }
 
+struct lruvec {
+        struct list_head lists[NR_LRU_LISTS];
+};
+
 /* Mask used at gathering information at once (see memcontrol.c) */
 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
@@ -364,10 +368,8 @@ struct zone {
         ZONE_PADDING(_pad1_)
 
         /* Fields commonly accessed by the page reclaim scanner */
-        spinlock_t              lru_lock;       
-        struct zone_lru {
-                struct list_head list;
-        } lru[NR_LRU_LISTS];
+        spinlock_t              lru_lock;
+        struct lruvec           lruvec;
 
         struct zone_reclaim_stat reclaim_stat;