page allocator: inline __rmqueue_smallest()

Inline __rmqueue_smallest by altering flow very slightly so that there is
only one call site.  Because there is only one call-site, this function
can then be inlined without causing text bloat.  On an x86-based config,
this patch reduces text by 16 bytes.
Signed-off-by: NMel Gorman <mel@csn.ul.ie>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -661,7 +661,8 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
  * Go through the free lists for the given migratetype and remove
  * the smallest available page from the freelists
  */
-static struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
+static inline
+struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
 						int migratetype)
 {
 	unsigned int current_order;
@@ -831,8 +832,7 @@ static struct page *__rmqueue_fallback(struct zone *zone, int order,
 		}
 	}
 
-	/* Use MIGRATE_RESERVE rather than fail an allocation */
-	return __rmqueue_smallest(zone, order, MIGRATE_RESERVE);
+	return NULL;
 }
 
 /*
@@ -844,11 +844,23 @@ static struct page *__rmqueue(struct zone *zone, unsigned int order,
 {
 	struct page *page;
 
+retry_reserve:
 	page = __rmqueue_smallest(zone, order, migratetype);
 
-	if (unlikely(!page))
+	if (unlikely(!page) && migratetype != MIGRATE_RESERVE) {
 		page = __rmqueue_fallback(zone, order, migratetype);
 
+		/*
+		 * Use MIGRATE_RESERVE rather than fail an allocation. goto
+		 * is used because __rmqueue_smallest is an inline function
+		 * and we want just one call site
+		 */
+		if (!page) {
+			migratetype = MIGRATE_RESERVE;
+			goto retry_reserve;
+		}
+	}
+
 	return page;
 }