mm: use is_migrate_highatomic() to simplify the code

Introduce two helpers, is_migrate_highatomic() and is_migrate_highatomic_page().

Simplify the code, no functional changes.

[akpm@linux-foundation.org: use static inlines rather than macros, per mhocko]
Link: http://lkml.kernel.org/r/58B94F15.6060606@huawei.com
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mmzone.h

@@ -35,7 +35,7 @@
  */
 #define PAGE_ALLOC_COSTLY_ORDER 3
 
-enum {
+enum migratetype {
 	MIGRATE_UNMOVABLE,
 	MIGRATE_MOVABLE,
 	MIGRATE_RECLAIMABLE,

mm/internal.h

@@ -510,4 +510,14 @@ extern const struct trace_print_flags pageflag_names[];
 extern const struct trace_print_flags vmaflag_names[];
 extern const struct trace_print_flags gfpflag_names[];
 
+static inline bool is_migrate_highatomic(enum migratetype migratetype)
+{
+	return migratetype == MIGRATE_HIGHATOMIC;
+}
+
+static inline bool is_migrate_highatomic_page(struct page *page)
+{
+	return get_pageblock_migratetype(page) == MIGRATE_HIGHATOMIC;
+}
+
 #endif	/* __MM_INTERNAL_H */

mm/page_alloc.c

@@ -2036,8 +2036,8 @@ static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
 
 	/* Yoink! */
 	mt = get_pageblock_migratetype(page);
-	if (mt != MIGRATE_HIGHATOMIC &&
-			!is_migrate_isolate(mt) && !is_migrate_cma(mt)) {
+	if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt)
+	    && !is_migrate_cma(mt)) {
 		zone->nr_reserved_highatomic += pageblock_nr_pages;
 		set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
 		move_freepages_block(zone, page, MIGRATE_HIGHATOMIC);
@@ -2094,8 +2094,7 @@ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
 			 * from highatomic to ac->migratetype. So we should
 			 * adjust the count once.
 			 */
-			if (get_pageblock_migratetype(page) ==
-							MIGRATE_HIGHATOMIC) {
+			if (is_migrate_highatomic_page(page)) {
 				/*
 				 * It should never happen but changes to
 				 * locking could inadvertently allow a per-cpu
@@ -2152,8 +2151,7 @@ __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype)
 
 		page = list_first_entry(&area->free_list[fallback_mt],
 						struct page, lru);
-		if (can_steal &&
-			get_pageblock_migratetype(page) != MIGRATE_HIGHATOMIC)
+		if (can_steal && !is_migrate_highatomic_page(page))
 			steal_suitable_fallback(zone, page, start_migratetype);
 
 		/* Remove the page from the freelists */
@@ -2493,7 +2491,7 @@ void free_hot_cold_page(struct page *page, bool cold)
 	/*
 	 * We only track unmovable, reclaimable and movable on pcp lists.
 	 * Free ISOLATE pages back to the allocator because they are being
-	 * offlined but treat RESERVE as movable pages so we can get those
+	 * offlined but treat HIGHATOMIC as movable pages so we can get those
 	 * areas back if necessary. Otherwise, we may have to free
 	 * excessively into the page allocator
 	 */
@@ -2603,7 +2601,7 @@ int __isolate_free_page(struct page *page, unsigned int order)
 		for (; page < endpage; page += pageblock_nr_pages) {
 			int mt = get_pageblock_migratetype(page);
 			if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
-				&& mt != MIGRATE_HIGHATOMIC)
+			    && !is_migrate_highatomic(mt))
 				set_pageblock_migratetype(page,
 							  MIGRATE_MOVABLE);
 		}