f2fs: add a tracepoint for sync_dirty_inodes

This patch adds a tracepoint for sync_dirty_inodes.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 53044ea..fdd43f7 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -803,6 +803,11 @@
 	struct list_head *head;
 	struct inode *inode;
 	struct f2fs_inode_info *fi;
+	bool is_dir = (type == DIR_INODE);
+
+	trace_f2fs_sync_dirty_inodes_enter(sbi->sb, is_dir,
+				get_pages(sbi, is_dir ?
+				F2FS_DIRTY_DENTS : F2FS_DIRTY_DATA));
 retry:
 	if (unlikely(f2fs_cp_error(sbi)))
 		return;
@@ -812,6 +817,9 @@
 	head = &sbi->inode_list[type];
 	if (list_empty(head)) {
 		spin_unlock(&sbi->inode_lock[type]);
+		trace_f2fs_sync_dirty_inodes_exit(sbi->sb, is_dir,
+				get_pages(sbi, is_dir ?
+				F2FS_DIRTY_DENTS : F2FS_DIRTY_DATA));
 		return;
 	}
 	fi = list_entry(head->next, struct f2fs_inode_info, dirty_list);