f2fs: readahead multi pages of directory for performance

We have no so such readahead mechanism in ->iterate() path as the one in
->read() path, it cause low performance when we read large directory.
This patch add readahead in f2fs_readdir() for better performance.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index e77be7cb1e60..2b67679f88b6 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -182,6 +182,8 @@ enum {
 
 #define F2FS_LINK_MAX           32000   /* maximum link count per file */
 
+#define MAX_DIR_RA_PAGES        4       /* maximum ra pages of dir */
+
 /* for in-memory extent cache entry */
 #define F2FS_MIN_EXTENT_LEN     16      /* minimum extent length */