[PATCH] mm/slub: calculate start order with reserved in consideration

[Wei Yang <weiyang@linux.vnet.ibm.com>]

In function slub_order(), the order starts from max(min_order,
get_order(min_objects * size)). When (min_objects * size) has different
order with (min_objects * size + reserved), it will skip this order by the
check in the loop.

This patch optimizes this a little by calculating the start order with
reserved in consideration and remove the check in loop.

Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>

---
This patch is based on the previous one "mm/slub: use get_order() instead of
fls()", so may not apply on current tree.

---
 mm/slub.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index e309ed1..e1bb147 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2912,19 +2912,15 @@ static inline int slab_order(int size, int min_objects,
 	if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
 		return get_order(size * MAX_OBJS_PER_PAGE) - 1;
 
-	for (order = max(min_order, get_order(min_objects * size));
+	for (order = max(min_order, get_order(min_objects * size + reserved));
 			order <= max_order; order++) {
 
 		unsigned long slab_size = PAGE_SIZE << order;
 
-		if (slab_size < min_objects * size + reserved)
-			continue;
-
 		rem = (slab_size - reserved) % size;
 
 		if (rem <= slab_size / fract_leftover)
 			break;
-
 	}
 
 	return order;
-- 
2.5.0

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