[PATCH 4/5] mm:swap: respect page_cluster for readahead

[Minchan Kim]

page_cluster 0 means "we don't want readahead" so in the case,
let's skip the readahead detection logic.

Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
 include/linux/swap.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 0f54b491e118..739d94397c47 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -427,7 +427,8 @@ extern bool has_usable_swap(void);
 
 static inline bool swap_use_vma_readahead(void)
 {
-	return READ_ONCE(swap_vma_readahead) && !atomic_read(&nr_rotate_swap);
+	return page_cluster > 0 && READ_ONCE(swap_vma_readahead)
+				&& !atomic_read(&nr_rotate_swap);
 }
 
 /* Swap 50% full? Release swapcache more aggressively.. */
-- 
2.7.4