Andrew Morton wrote:
On Fri, 13 Jul 2007 18:36:54 -0700
Badari Pulavarty <pbadari@xxxxxxxxxx> wrote:
More statfs() improvements for ext2. ext2 already maintains
percpu counters for free blocks and inodes. Derive free
block count and inode count by summing up percpu counters,
instead of counting up all the groups in the filesystem
each time.
Signed-off-by: Badari Pulavarty <pbadari@xxxxxxxxxx>
Acked-by: Andreas Dilger <adilger@xxxxxxxxxxxxx>
fs/ext2/super.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Index: linux-2.6.22/fs/ext2/super.c
===================================================================
--- linux-2.6.22.orig/fs/ext2/super.c 2007-07-13 20:06:38.000000000 -0700
+++ linux-2.6.22/fs/ext2/super.c 2007-07-13 20:06:51.000000000 -0700
@@ -1136,12 +1136,12 @@ static int ext2_statfs (struct dentry *
buf->f_type = EXT2_SUPER_MAGIC;
buf->f_bsize = sb->s_blocksize;
buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
- buf->f_bfree = ext2_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 = ext2_count_free_inodes(sb);
+ buf->f_ffree = percpu_counter_sum(&sbi->s_freeinodes_counter);
buf->f_namelen = EXT2_NAME_LEN;
fsid = le64_to_cpup((void *)es->s_uuid) ^
le64_to_cpup((void *)es->s_uuid + sizeof(u64));
Guys, I have this patch in a stalled state pending some convincing
demonstration/argument that it's actually a worthwhile change.
How much hurt will it cause on large-numa, and how much benefit do we get
for that hurt?
Unfortunately, I couldn't find any noticeable significant improvements
with or without this patch.
May be none of my filesystems are large enough on a large enough NUMA
box to verify.
Lets drop it for now and re-visit it if needed.
Thanks,
Badari
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