On Thu, Feb 06, 2020 at 06:09:41PM -0700, Andreas Dilger wrote:
> Pack struct dx_dir_info and dx_dirblock_info properly in memory, to
> avoid holes, and fields are not larger than necessary. This reduces
> the memory needed for each hashed dir, according to pahole(1) from:
>
> struct dx_dir_info {
> /* size: 32, cachelines: 1, members: 6 */
> /* sum members: 26, holes: 1, sum holes: 2 */
> /* padding: 4 */
> };
> struct dx_dirblock_info {
> /* size: 56, cachelines: 1, members: 9 */
> /* sum members: 48, holes: 2, sum holes: 8 */
> /* last cacheline: 56 bytes */
> };
>
> to 8 bytes less for each directory and directory block, and leaves
> space for future use if needed (e.g. larger numblocks):
>
> struct dx_dir_info {
> /* size: 24, cachelines: 1, members: 6 */
> /* sum members: 20, holes: 1, sum holes: 4 */
> /* bit holes: 1, sum bit holes: 7 bits */
> };
> struct dx_dirblock_info {
> /* size: 48, cachelines: 1, members: 9 */
> };
>
> Signed-off-by: Andreas Dilger <adilger@xxxxxxxxxxxxx>
> Lustre-bug-id: https://jira.whamcloud.com/browse/LU-13197
Applied, thanks.
- Ted
