Commit bbcbbd56 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe

block: optimize blk_bio_segment_split for single-page bvec

Introduce a fast path for single-page bvec IO, then we can avoid
to call bvec_split_segs() unnecessarily.
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 48d7727c
...@@ -286,10 +286,16 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, ...@@ -286,10 +286,16 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
bvprv = bv; bvprv = bv;
bvprvp = &bvprv; bvprvp = &bvprv;
if (bvec_split_segs(q, &bv, &nsegs, &seg_size, if (bv.bv_offset + bv.bv_len <= PAGE_SIZE) {
&front_seg_size, &sectors)) nsegs++;
seg_size = bv.bv_len;
sectors += bv.bv_len >> 9;
if (nsegs == 1 && seg_size > front_seg_size)
front_seg_size = seg_size;
} else if (bvec_split_segs(q, &bv, &nsegs, &seg_size,
&front_seg_size, &sectors)) {
goto split; goto split;
}
} }
do_split = false; do_split = false;
......
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