f2fs: introduce sysfs readdir_ra to readahead inode block in readdir

This patch introduces a sysfs interface readdir_ra to enable/disable
readaheading inode block in f2fs_readdir. When readdir_ra is enabled,
it improves the performance of "readdir + stat".

For 300,000 files:
	time find /data/test > /dev/null
disable readdir_ra: 1m25.69s real  0m01.94s user  0m50.80s system
enable  readdir_ra: 0m18.55s real  0m00.44s user  0m15.39s system

Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index a7799c2fca2855eced4740cb6a82e5f26a448287..d870b5514d15a23de66d34f226f870ed0d94dd67 100644 (file)
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -186,3 +186,9 @@ Date:               August 2017
 Contact:       "Jaegeuk Kim" <jaegeuk@kernel.org>
 Description:
                 Controls sleep time of GC urgent mode
+
+What:          /sys/fs/f2fs/<disk>/readdir_ra
+Date:          November 2017
+Contact:       "Sheng Yong" <shengyong1@huawei.com>
+Description:
+                Controls readahead inode block in readdir.

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 2d98d877c09dada99dfae36b45f85b3da75af095..724304dc6143cbfec3d50de353dbfd6dc87e9983 100644 (file)
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -798,6 +798,7 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
        unsigned int bit_pos;
        struct f2fs_dir_entry *de = NULL;
        struct fscrypt_str de_name = FSTR_INIT(NULL, 0);
+       struct f2fs_sb_info *sbi = F2FS_I_SB(d->inode);
 
        bit_pos = ((unsigned long)ctx->pos % d->max);
 
@@ -836,6 +837,9 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
                                        le32_to_cpu(de->ino), d_type))
                        return 1;
 
+               if (sbi->readdir_ra == 1)
+                       ra_node_page(sbi, le32_to_cpu(de->ino));
+
                bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
                ctx->pos = start_pos + bit_pos;
        }

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index ef68433a236336130649d625e0f259fe712e2f33..7cb79fbebb63bf1d2b51db2c18918d4fa748d5c3 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1093,6 +1093,7 @@ struct f2fs_sb_info {
        int dir_level;                          /* directory level */
        int inline_xattr_size;                  /* inline xattr size */
        unsigned int trigger_ssr_threshold;     /* threshold to trigger ssr */
+       int readdir_ra;                         /* readahead inode in readdir */
 
        block_t user_block_count;               /* # of user blocks */
        block_t total_valid_block_count;        /* # of valid blocks */

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 9835348b6e5d200b71112c2eb65ad101d5bd3be0..93c3364250dd05e1774a1188380eee7c1787dd6b 100644 (file)
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -299,6 +299,7 @@ F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, dir_level, dir_level);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, cp_interval, interval_time[CP_TIME]);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, idle_interval, interval_time[REQ_TIME]);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, iostat_enable, iostat_enable);
+F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, readdir_ra, readdir_ra);
 #ifdef CONFIG_F2FS_FAULT_INJECTION
 F2FS_RW_ATTR(FAULT_INFO_RATE, f2fs_fault_info, inject_rate, inject_rate);
 F2FS_RW_ATTR(FAULT_INFO_TYPE, f2fs_fault_info, inject_type, inject_type);
@@ -346,6 +347,7 @@ static struct attribute *f2fs_attrs[] = {
        ATTR_LIST(cp_interval),
        ATTR_LIST(idle_interval),
        ATTR_LIST(iostat_enable),
+       ATTR_LIST(readdir_ra),
 #ifdef CONFIG_F2FS_FAULT_INJECTION
        ATTR_LIST(inject_rate),
        ATTR_LIST(inject_type),