With the latest patchset from Tejun, we grew the request structure a little bit. It's been quite a while since I've taken a look at the layout of the structure, this patchset is a first attempt at doing that.
One advantage of Tejun's patchset is that we no longer rely on the atomic complete flag on blk-mq. We can use that to shuffle some bits, and reclaim the full atomic_flags field. Cache optimize the layout of struct request a bit, to group things a little more logically. Not a huge shuffle, just a few select members. We end up doing better in synthetic testing after this, details in the last patch. -- Jens Axboe
