ext4: address scalability issue by removing extent cache statistics

Andi Kleen and Tim Chen have reported that under certain circumstances
the extent cache statistics are causing scalability problems due to
cache line bounces.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

1 files changed, 0 insertions, 16 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ceebaf853beb..ef7db5044262 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2366,18 +2366,6 @@ static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
                           EXT4_SB(sb)->s_sectors_written_start) >> 1)));
 }
 
-static ssize_t extent_cache_hits_show(struct ext4_attr *a,
-                                      struct ext4_sb_info *sbi, char *buf)
-{
-        return snprintf(buf, PAGE_SIZE, "%lu\n", sbi->extent_cache_hits);
-}
-
-static ssize_t extent_cache_misses_show(struct ext4_attr *a,
-                                        struct ext4_sb_info *sbi, char *buf)
-{
-        return snprintf(buf, PAGE_SIZE, "%lu\n", sbi->extent_cache_misses);
-}
-
 static ssize_t inode_readahead_blks_store(struct ext4_attr *a,
                                           struct ext4_sb_info *sbi,
                                           const char *buf, size_t count)
@@ -2435,8 +2423,6 @@ static struct ext4_attr ext4_attr_##name = __ATTR(name, mode, show, store)
 EXT4_RO_ATTR(delayed_allocation_blocks);
 EXT4_RO_ATTR(session_write_kbytes);
 EXT4_RO_ATTR(lifetime_write_kbytes);
-EXT4_RO_ATTR(extent_cache_hits);
-EXT4_RO_ATTR(extent_cache_misses);
 EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, sbi_ui_show,
                  inode_readahead_blks_store, s_inode_readahead_blks);
 EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal);
@@ -2452,8 +2438,6 @@ static struct attribute *ext4_attrs[] = {
         ATTR_LIST(delayed_allocation_blocks),
         ATTR_LIST(session_write_kbytes),
         ATTR_LIST(lifetime_write_kbytes),
-        ATTR_LIST(extent_cache_hits),
-        ATTR_LIST(extent_cache_misses),
         ATTR_LIST(inode_readahead_blks),
         ATTR_LIST(inode_goal),
         ATTR_LIST(mb_stats),