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

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
......@@ -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;
......
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