mm: add link from struct lruvec to struct zone

This is the first stage of struct mem_cgroup_zone removal.  Further
patches replace struct mem_cgroup_zone with a pointer to struct lruvec.

If CONFIG_CGROUP_MEM_RES_CTLR=n lruvec_zone() is just container_of().

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: 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, 14 insertions, 0 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 5c4880bc027a..2427706f78b4 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -201,6 +201,9 @@ struct zone_reclaim_stat {
 struct lruvec {
         struct list_head lists[NR_LRU_LISTS];
         struct zone_reclaim_stat reclaim_stat;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+        struct zone *zone;
+#endif
 };
 
 /* Mask used at gathering information at once (see memcontrol.c) */
@@ -729,6 +732,17 @@ extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
                                      unsigned long size,
                                      enum memmap_context context);
 
+extern void lruvec_init(struct lruvec *lruvec, struct zone *zone);
+
+static inline struct zone *lruvec_zone(struct lruvec *lruvec)
+{
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+        return lruvec->zone;
+#else
+        return container_of(lruvec, struct zone, lruvec);
+#endif
+}
+
 #ifdef CONFIG_HAVE_MEMORY_PRESENT
 void memory_present(int nid, unsigned long start, unsigned long end);
 #else