Messages in this thread | | | Date | Thu, 10 Mar 2016 11:41:49 +0800 | Subject | Re: [PATCH] blk-merge: compute bio->bi_seg_front_size efficiently | From | Ming Lei <> |
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On Tue, Mar 1, 2016 at 8:51 PM, Ming Lei <ming.lei@canonical.com> wrote: > It is enough to check and compute bio->bi_seg_front_size just > after the 1st segment is found, but current code checks that > for each bvec, which is inefficient. > > This patch follows the way in __blk_recalc_rq_segments() > for computing bio->bi_seg_front_size, and it is more efficient > and code becomes more readable too.
Gentle ping, :-)
IMO, it is nice to follow the logic in __blk_recalc_rq_segments(), so hope this one can be merged in for-next soon.
Thanks, Ming
> > Signed-off-by: Ming Lei <ming.lei@canonical.com> > --- > block/blk-merge.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/block/blk-merge.c b/block/blk-merge.c > index 2613531..e4c74a0 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -131,22 +131,21 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, > bvprvp = &bvprv; > sectors += bv.bv_len >> 9; > > - if (nsegs == 1 && seg_size > front_seg_size) > - front_seg_size = seg_size; > continue; > } > new_segment: > if (nsegs == queue_max_segments(q)) > goto split; > > + if (nsegs == 1 && seg_size > front_seg_size) > + front_seg_size = seg_size; > + > nsegs++; > bvprv = bv; > bvprvp = &bvprv; > seg_size = bv.bv_len; > sectors += bv.bv_len >> 9; > > - if (nsegs == 1 && seg_size > front_seg_size) > - front_seg_size = seg_size; > } > > do_split = false; > @@ -159,6 +158,8 @@ split: > bio = new; > } > > + if (nsegs == 1 && seg_size > front_seg_size) > + front_seg_size = seg_size; > bio->bi_seg_front_size = front_seg_size; > if (seg_size > bio->bi_seg_back_size) > bio->bi_seg_back_size = seg_size; > -- > 1.9.1 >
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