Re: [PATCH 4/4] xfs: remove nr_to_write writeback windup.

Jan Kara
2010-04-22T19:07:36Z

On Tue 20-04-10 12:41:54, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Now that the background flush code has been fixed, we shouldn't need to
> silently multiply the wbc->nr_to_write to get good writeback. Remove
> that code.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
> fs/xfs/linux-2.6/xfs_aops.c | 8 --------
> 1 files changed, 0 insertions(+), 8 deletions(-)
>
> diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
> index 9962850..2b2225d 100644
> --- a/fs/xfs/linux-2.6/xfs_aops.c
> +++ b/fs/xfs/linux-2.6/xfs_aops.c
> @@ -1336,14 +1336,6 @@ xfs_vm_writepage(
> if (!page_has_buffers(page))
> create_empty_buffers(page, 1 << inode->i_blkbits, 0);
>
> -
> - /*
> - * VM calculation for nr_to_write seems off. Bump it way
> - * up, this gets simple streaming writes zippy again.
> - * To be reviewed again after Jens' writeback changes.
> - */
> - wbc->nr_to_write *= 4;
> -
Hum, are you sure about this? I thought it's there because VM passes at
most 1024 pages to write from background writeback and you wanted to write
more in one go (at least ext4 wants to do this).

Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR