[PATCH 15/18] xfs; pack xfs_buf structure more tightly

[Alex Elder]

On Tue, 2010-09-14 at 20:56 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner at redhat.com>
> 
> pahole reports the struct xfs_buf has quite a few holes in it, so
> packing the structure better will reduce the size of it by 16 bytes.
> Also, move all the fields used in cache lookups into the first
> cacheline.
> 
> Before on x86_64:
> 
>         /* size: 320, cachelines: 5 */
> 	/* sum members: 298, holes: 6, sum holes: 22 */
> 
> After on x86_64:
> 
>         /* size: 304, cachelines: 5 */
> 	/* padding: 6 */
> 	/* last cacheline: 48 bytes */

Looks good.

Reviewed-by: Alex Elder <aelder at sgi.com>

> Signed-off-by: Dave Chinner <dchinner at redhat.com>
> ---
>  fs/xfs/linux-2.6/xfs_buf.h |   30 +++++++++++++++++++-----------
>  1 files changed, 19 insertions(+), 11 deletions(-)