ext4: Use struct flex_groups to calculate get_orlov_stats()

Instead of looping over all of the block groups in a flex group
summing their summary statistics, start tracking used_dirs in struct
flex_groups, and use struct flex_groups instead.  This should save a
bit of CPU for mkdir-heavy workloads.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index e52b48f86ed..46aaaa2ed4c 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -172,6 +172,7 @@ struct ext4_group_desc
 struct flex_groups {
 	atomic_t free_inodes;
 	atomic_t free_blocks;
+	atomic_t used_dirs;
 };
 
 #define EXT4_BG_INODE_UNINIT	0x0001 /* Inode table/bitmap not in use */