Commit b000ae0e authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring/rsrc: optimise single entry advance 



Iterating within the first bvec entry should be essentially free, but we
use iov_iter_advance() for that, which shows up in benchmark profiles
taking up to 0.5% of CPU. Replace it with a hand coded version.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent edd47826

io_uring/rsrc.c

+4 −1
Original line number Diff line number Diff line
@@ -1364,7 +1364,10 @@ int io_import_fixed(int ddir, struct iov_iter *iter, 
		const struct bio_vec *bvec = imu->bvec;



		if (offset <= bvec->bv_len) {

			iov_iter_advance(iter, offset);

			iter->bvec = bvec;

			iter->nr_segs = bvec->bv_len;

			iter->count -= offset;

			iter->iov_offset = offset;

		} else {

			unsigned long seg_skip;