mm: zone_reclaim: compaction: export compact_zone_order()

Needed by zone_reclaim_mode compaction-awareness.

include/linux/compaction.h

@@ -40,6 +40,9 @@ extern int fragmentation_index(struct zone *zone, unsigned int order);
 extern unsigned long try_to_compact_pages(gfp_t gfp_mask, unsigned int order,
 			int alloc_flags, const struct alloc_context *ac,
 			enum migrate_mode mode, int *contended);
+extern unsigned long compact_zone_order(struct zone *zone, int order,
+		gfp_t gfp_mask, enum migrate_mode mode, int *contended,
+		int alloc_flags, int classzone_idx);
 extern void compact_pgdat(pg_data_t *pgdat, int order);
 extern unsigned long compaction_suitable(struct zone *zone, int order,
 					int alloc_flags, int classzone_idx);
@@ -59,6 +62,13 @@ static inline unsigned long try_to_compact_pages(gfp_t gfp_mask,
 	return COMPACT_CONTINUE;
 }
 
+static inline unsigned long compact_zone_order(struct zone *zone, int order,
+		gfp_t gfp_mask, enum migrate_mode mode, int *contended,
+		int alloc_flags, int classzone_idx)
+{
+	return COMPACT_CONTINUE;
+}
+
 static inline void compact_pgdat(pg_data_t *pgdat, int order)
 {
 }

mm/compaction.c

@@ -1440,7 +1440,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
 	return ret;
 }
 
-static unsigned long compact_zone_order(struct zone *zone, int order,
+unsigned long compact_zone_order(struct zone *zone, int order,
 		gfp_t gfp_mask, enum migrate_mode mode, int *contended,
 		int alloc_flags, int classzone_idx)
 {