[PATCH] fast ext3_statfs
Under I/O load it may take up to a dozen seconds to read all group
descriptors. This is what ext3_statfs() does. At the same time, we already
maintain global numbers of free inodes/blocks. Why don't we use them instead
of group reading and summing?
Cc: Ravikiran G Thirumalai <kiran@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index a3e2a8e..86e4431 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -2326,7 +2326,8 @@
static int ext3_statfs (struct super_block * sb, struct kstatfs * buf)
{
- struct ext3_super_block *es = EXT3_SB(sb)->s_es;
+ struct ext3_sb_info *sbi = EXT3_SB(sb);
+ struct ext3_super_block *es = sbi->s_es;
unsigned long overhead;
int i;
@@ -2368,12 +2369,12 @@
buf->f_type = EXT3_SUPER_MAGIC;
buf->f_bsize = sb->s_blocksize;
buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
- buf->f_bfree = ext3_count_free_blocks (sb);
+ buf->f_bfree = percpu_counter_sum(&sbi->s_freeblocks_counter);
buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
buf->f_bavail = 0;
buf->f_files = le32_to_cpu(es->s_inodes_count);
- buf->f_ffree = ext3_count_free_inodes (sb);
+ buf->f_ffree = percpu_counter_sum(&sbi->s_freeinodes_counter);
buf->f_namelen = EXT3_NAME_LEN;
return 0;
}