memcg: rename MEM_CGROUP_STAT_SWAPOUT as MEM_CGROUP_STAT_SWAP

MEM_CGROUP_STAT_SWAPOUT represents the usage of swap rather than
the number of swap-out events. Rename it to be MEM_CGROUP_STAT_SWAP.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memcontrol.c

@@ -87,7 +87,7 @@ enum mem_cgroup_stat_index {
 	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
 	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as anon rss */
 	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
-	MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
+	MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */
 	MEM_CGROUP_STAT_NSTATS,
 };
 
@@ -703,7 +703,7 @@ static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
 					 bool charge)
 {
 	int val = (charge) ? 1 : -1;
-	this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
+	this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
 }
 
 static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
@@ -3831,7 +3831,7 @@ static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
 	val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
 
 	if (swap)
-		val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAPOUT);
+		val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP);
 
 	return val << PAGE_SHIFT;
 }
@@ -4082,7 +4082,7 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
 	unsigned int i;
 
 	for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
-		if (i == MEM_CGROUP_STAT_SWAPOUT && !do_swap_account)
+		if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
 			continue;
 		seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
 			   mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
@@ -4109,7 +4109,7 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
 	for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
 		long long val = 0;
 
-		if (i == MEM_CGROUP_STAT_SWAPOUT && !do_swap_account)
+		if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
 			continue;
 		for_each_mem_cgroup_tree(mi, memcg)
 			val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;