e2fsck: reduce memory usage for many directories
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@whamcloud.com>
Lustre-bug-id: https://jira.whamcloud.com/browse/LU-13197
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
3 files changed
