+
+What: /sys/fs/f2fs/<disk>/gc_reclaimed_segments
+Date: July 2021
+Contact: "Daeho Jeong" <daehojeong@google.com>
+Description: Show how many segments have been reclaimed by GC during a specific
+ GC mode (0: GC normal, 1: GC idle CB, 2: GC idle greedy,
+ 3: GC idle AT, 4: GC urgent high, 5: GC urgent low)
+ You can re-initialize this value to "0".
+
+What: /sys/fs/f2fs/<disk>/gc_segment_mode
+Date: July 2021
+Contact: "Daeho Jeong" <daehojeong@google.com>
+Description: You can control for which gc mode the "gc_reclaimed_segments" node shows.
+ Refer to the description of the modes in "gc_reclaimed_segments".
+
+What: /sys/fs/f2fs/<disk>/seq_file_ra_mul
+Date: July 2021
+Contact: "Daeho Jeong" <daehojeong@google.com>
+Description: You can control the multiplier value of bdi device readahead window size
+ between 2 (default) and 256 for POSIX_FADV_SEQUENTIAL advise option.