mm, vmscan: make shrink_node decisions more node-centric

Earlier patches focused on having direct reclaim and kswapd use data
that is node-centric for reclaiming but shrink_node() itself still uses
too much zone information.  This patch removes unnecessary zone-based
information with the most important decision being whether to continue
reclaim or not.  Some memcg APIs are adjusted as a result even though
memcg itself still uses some zone information.

[mgorman@techsingularity.net: optimization]
  Link: http://lkml.kernel.org/r/1468588165-12461-2-git-send-email-mgorman@techsingularity.net
Link: http://lkml.kernel.org/r/1467970510-21195-14-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 13 insertions, 12 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 6d2321c148cd..f4963ee4fdbc 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -324,22 +324,23 @@ mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone)
 }
 
 /**
- * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
+ * mem_cgroup_lruvec - get the lru list vector for a node or a memcg zone
+ * @node: node of the wanted lruvec
  * @zone: zone of the wanted lruvec
  * @memcg: memcg of the wanted lruvec
  *
- * Returns the lru list vector holding pages for the given @zone and
- * @mem.  This can be the global zone lruvec, if the memory controller
+ * Returns the lru list vector holding pages for a given @node or a given
+ * @memcg and @zone. This can be the node lruvec, if the memory controller
  * is disabled.
  */
-static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
-						    struct mem_cgroup *memcg)
+static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
+				struct zone *zone, struct mem_cgroup *memcg)
 {
 	struct mem_cgroup_per_zone *mz;
 	struct lruvec *lruvec;
 
 	if (mem_cgroup_disabled()) {
-		lruvec = zone_lruvec(zone);
+		lruvec = node_lruvec(pgdat);
 		goto out;
 	}
 
@@ -609,10 +610,10 @@ static inline void mem_cgroup_migrate(struct page *old, struct page *new)
 {
 }
 
-static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
-						    struct mem_cgroup *memcg)
+static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
+				struct zone *zone, struct mem_cgroup *memcg)
 {
-	return zone_lruvec(zone);
+	return node_lruvec(pgdat);
 }
 
 static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 4062fa74526f..895c365e3259 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -739,9 +739,9 @@ static inline spinlock_t *zone_lru_lock(struct zone *zone)
 	return &zone->zone_pgdat->lru_lock;
 }
 
-static inline struct lruvec *zone_lruvec(struct zone *zone)
+static inline struct lruvec *node_lruvec(struct pglist_data *pgdat)
 {
-	return &zone->zone_pgdat->lruvec;
+	return &pgdat->lruvec;
 }
 
 static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 916e2eddecd6..0ad616d7c381 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -316,7 +316,7 @@ extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 						  unsigned long nr_pages,
 						  gfp_t gfp_mask,
 						  bool may_swap);
-extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
+extern unsigned long mem_cgroup_shrink_node(struct mem_cgroup *mem,
 						gfp_t gfp_mask, bool noswap,
 						struct zone *zone,
 						unsigned long *nr_scanned);