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@xxxxxxxxxxx>
---
fs/f2fs/dir.c | 6 ++++++
fs/f2fs/f2fs.h | 2 ++
2 files changed, 8 insertions(+)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 972fd0e..3581c2b 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -637,11 +637,17 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx)
struct f2fs_dentry_block *dentry_blk = NULL;
struct f2fs_dir_entry *de = NULL;
struct page *dentry_page = NULL;
+ struct file_ra_state *ra = &file->f_ra;
unsigned int n = ((unsigned long)ctx->pos / NR_DENTRY_IN_BLOCK);
unsigned char d_type = DT_UNKNOWN;
bit_pos = ((unsigned long)ctx->pos % NR_DENTRY_IN_BLOCK);
+ /* readahead for multi pages of dir */
+ if (npages - n > 1 && !ra_has_index(ra, n))
+ page_cache_sync_readahead(inode->i_mapping, ra, file, n,
+ min(npages - n, (pgoff_t)MAX_DIR_RA_PAGES));
+
for (; n < npages; n++) {
dentry_page = get_lock_data_page(inode, n);
if (IS_ERR(dentry_page))
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index e77be7c..2b67679 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 */
--
1.7.9.5
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