mm/vmstat.c: fix/cleanup ifdefs

CONFIG_COMPACTION=y, CONFIG_DEBUG_FS=n:

  mm/vmstat.c:690: warning: 'frag_start' defined but not used
  mm/vmstat.c:702: warning: 'frag_next' defined but not used
  mm/vmstat.c:710: warning: 'frag_stop' defined but not used
  mm/vmstat.c:715: warning: 'walk_zones_in_node' defined but not used

It's all a bit of a tangly mess and it's unclear why CONFIG_COMPACTION
figures in there at all.  Move frag_start/frag_next/frag_stop and
migratetype_names[] into the existing CONFIG_PROC_FS block.

walk_zones_in_node() gets a special ifdef.

Also move the #include lines up to where #include lines live.

[axel.lin@ingics.com: fix build error when !CONFIG_PROC_FS]
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Tested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmstat.c

@@ -17,6 +17,9 @@
 #include <linux/cpu.h>
 #include <linux/cpumask.h>
 #include <linux/vmstat.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
 #include <linux/sched.h>
 #include <linux/math64.h>
 #include <linux/writeback.h>
@@ -670,66 +673,6 @@ int fragmentation_index(struct zone *zone, unsigned int order)
 }
 #endif
 
-#if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-
-static char * const migratetype_names[MIGRATE_TYPES] = {
-	"Unmovable",
-	"Reclaimable",
-	"Movable",
-	"Reserve",
-#ifdef CONFIG_CMA
-	"CMA",
-#endif
-#ifdef CONFIG_MEMORY_ISOLATION
-	"Isolate",
-#endif
-};
-
-static void *frag_start(struct seq_file *m, loff_t *pos)
-{
-	pg_data_t *pgdat;
-	loff_t node = *pos;
-	for (pgdat = first_online_pgdat();
-	     pgdat && node;
-	     pgdat = next_online_pgdat(pgdat))
-		--node;
-
-	return pgdat;
-}
-
-static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
-{
-	pg_data_t *pgdat = (pg_data_t *)arg;
-
-	(*pos)++;
-	return next_online_pgdat(pgdat);
-}
-
-static void frag_stop(struct seq_file *m, void *arg)
-{
-}
-
-/* Walk all the zones in a node and print using a callback */
-static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
-		void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
-{
-	struct zone *zone;
-	struct zone *node_zones = pgdat->node_zones;
-	unsigned long flags;
-
-	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
-		if (!populated_zone(zone))
-			continue;
-
-		spin_lock_irqsave(&zone->lock, flags);
-		print(m, pgdat, zone);
-		spin_unlock_irqrestore(&zone->lock, flags);
-	}
-}
-#endif
-
 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
 #ifdef CONFIG_ZONE_DMA
 #define TEXT_FOR_DMA(xx) xx "_dma",
@@ -907,7 +850,66 @@ const char * const vmstat_text[] = {
 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
 
 
+#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
+     defined(CONFIG_PROC_FS)
+static void *frag_start(struct seq_file *m, loff_t *pos)
+{
+	pg_data_t *pgdat;
+	loff_t node = *pos;
+
+	for (pgdat = first_online_pgdat();
+	     pgdat && node;
+	     pgdat = next_online_pgdat(pgdat))
+		--node;
+
+	return pgdat;
+}
+
+static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
+{
+	pg_data_t *pgdat = (pg_data_t *)arg;
+
+	(*pos)++;
+	return next_online_pgdat(pgdat);
+}
+
+static void frag_stop(struct seq_file *m, void *arg)
+{
+}
+
+/* Walk all the zones in a node and print using a callback */
+static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
+		void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
+{
+	struct zone *zone;
+	struct zone *node_zones = pgdat->node_zones;
+	unsigned long flags;
+
+	for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
+		if (!populated_zone(zone))
+			continue;
+
+		spin_lock_irqsave(&zone->lock, flags);
+		print(m, pgdat, zone);
+		spin_unlock_irqrestore(&zone->lock, flags);
+	}
+}
+#endif
+
 #ifdef CONFIG_PROC_FS
+static char * const migratetype_names[MIGRATE_TYPES] = {
+	"Unmovable",
+	"Reclaimable",
+	"Movable",
+	"Reserve",
+#ifdef CONFIG_CMA
+	"CMA",
+#endif
+#ifdef CONFIG_MEMORY_ISOLATION
+	"Isolate",
+#endif
+};
+
 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 						struct zone *zone)
 {
@@ -1536,8 +1538,6 @@ static int __init setup_vmstat(void)
 module_init(setup_vmstat)
 
 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
-#include <linux/debugfs.h>
-
 
 /*
  * Return an index indicating how much of the available free memory is