ext4: count hits/misses of extent cache and expose in sysfs
The number of hits and misses for each filesystem is exposed in
/sys/fs/ext4/<dev>/extent_cache_{hits, misses}.
Tested: fsstress, manual checks.
Signed-off-by: Vivek Haldar <haldar@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 6ce3c7c..65fe1dc0 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1144,6 +1144,9 @@
unsigned long s_ext_blocks;
unsigned long s_ext_extents;
#endif
+ /* ext4 extent cache stats */
+ unsigned long extent_cache_hits;
+ unsigned long extent_cache_misses;
/* for buddy allocator */
struct ext4_group_info ***s_group_info;
