ext4: Use atomic_t's in struct flex_groups

Reduce pressure on the sb_bgl_lock family of locks by using atomic_t's
to track the number of free blocks and inodes in each flex_group.

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

1 files changed, 4 insertions, 4 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 1ec554cc107..6b5d5c6399f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1630,10 +1630,10 @@ static int ext4_fill_flex_info(struct super_block *sb)
                 gdp = ext4_get_group_desc(sb, i, &bh);
 
                 flex_group = ext4_flex_group(sbi, i);
-                sbi->s_flex_groups[flex_group].free_inodes +=
-                        ext4_free_inodes_count(sb, gdp);
-                sbi->s_flex_groups[flex_group].free_blocks +=
-                        ext4_free_blks_count(sb, gdp);
+                atomic_set(&sbi->s_flex_groups[flex_group].free_inodes,
+                           ext4_free_inodes_count(sb, gdp));
+                atomic_set(&sbi->s_flex_groups[flex_group].free_blocks,
+                           ext4_free_blks_count(sb, gdp));
         }
 
         return 1;