Commit
966a967116e6 randomly added alignment to this structure, but
it's actually detrimental to performance of null_blk. Test case:
Running on both the home and remote node shows a ~5% degradation
in performance.
While in there, move blk_status_t to the hole after the integer tag
in the nullb_cmd structure. After this patch, we shrink the size
from 192 to 152 bytes.
Fixes:
966a967116e69 ("smp: Avoid using two cache lines for struct call_single_data")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
struct nullb_cmd {
struct list_head list;
struct llist_node ll_list;
- call_single_data_t csd;
+ struct __call_single_data csd;
struct request *rq;
struct bio *bio;
unsigned int tag;
+ blk_status_t error;
struct nullb_queue *nq;
struct hrtimer timer;
- blk_status_t error;
};
struct nullb_queue {