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authorMing Lei <ming.lei@redhat.com>2019-02-27 20:40:12 +0800
committerJens Axboe <axboe@kernel.dk>2019-02-27 06:18:55 -0700
commitbbcbbd567cc15823a6e9d4e2c5899ea3defa7b6d (patch)
tree22cd9755657f63bd596496b2e59b866d3833f0d1 /block
parent48d7727cae1209235700ed90f8f11426027b333b (diff)
downloadlinux-stericsson-bbcbbd567cc15823a6e9d4e2c5899ea3defa7b6d.tar.gz
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: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-merge.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c
index c1ad8abbd9d6..9402a7c3ba22 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -286,10 +286,16 @@ new_segment:
bvprv = bv;
bvprvp = &bvprv;
- if (bvec_split_segs(q, &bv, &nsegs, &seg_size,
- &front_seg_size, &sectors))
+ if (bv.bv_offset + bv.bv_len <= PAGE_SIZE) {
+ 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;
-
+ }
}
do_split = false;