From: Ming Lei <tom.leiming@gmail.com>
To: Jens Axboe <axboe@fb.com>, linux-kernel@vger.kernel.org
Cc: linux-block@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
Ming Lei <tom.leiming@gmail.com>, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH v1 24/54] blk-merge: compute bio->bi_seg_front_size efficiently
Date: Tue, 27 Dec 2016 23:56:13 +0800 [thread overview]
Message-ID: <1482854250-13481-25-git-send-email-tom.leiming@gmail.com> (raw)
In-Reply-To: <1482854250-13481-1-git-send-email-tom.leiming@gmail.com>
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.
Signed-off-by: Ming Lei <tom.leiming@gmail.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 182398cb1524..e3abc835e4b7 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -153,22 +153,21 @@ 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;
@@ -181,6 +180,8 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
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;
--
2.7.4
next prev parent reply other threads:[~2016-12-27 16:03 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1482854250-13481-1-git-send-email-tom.leiming@gmail.com>
2016-12-27 15:55 ` [PATCH v1 01/54] block: drbd: comment on direct access bvec table Ming Lei
2016-12-27 15:55 ` [PATCH v1 02/54] block: loop: comment on direct access to " Ming Lei
2016-12-27 15:55 ` [PATCH v1 03/54] kernel/power/swap.c: " Ming Lei
2016-12-27 15:55 ` [PATCH v1 04/54] mm: page_io.c: " Ming Lei
2016-12-27 15:55 ` [PATCH v1 05/54] fs/buffer: " Ming Lei
2016-12-27 15:55 ` [PATCH v1 06/54] f2fs: f2fs_read_end_io: " Ming Lei
2016-12-27 15:55 ` [PATCH v1 07/54] bcache: " Ming Lei
2016-12-30 16:56 ` Coly Li
2016-12-27 15:55 ` [PATCH v1 08/54] block: comment on bio_alloc_pages() Ming Lei
2016-12-30 10:40 ` Coly Li
2016-12-30 11:06 ` Coly Li
2016-12-27 15:55 ` [PATCH v1 09/54] block: comment on bio_iov_iter_get_pages() Ming Lei
2016-12-27 15:55 ` [PATCH v1 10/54] block: introduce flag QUEUE_FLAG_NO_MP Ming Lei
2016-12-27 15:56 ` [PATCH v1 11/54] md: set NO_MP for request queue of md Ming Lei
2016-12-27 15:56 ` [PATCH v1 12/54] dm: limit the max bio size as BIO_MAX_PAGES * PAGE_SIZE Ming Lei
2017-01-03 16:43 ` Mike Snitzer
2017-01-06 3:30 ` Ming Lei
2016-12-27 15:56 ` [PATCH v1 13/54] block: comments on bio_for_each_segment[_all] Ming Lei
2016-12-27 15:56 ` [PATCH v1 14/54] block: introduce multipage/single page bvec helpers Ming Lei
2016-12-27 15:56 ` [PATCH v1 15/54] block: implement sp version of bvec iterator helpers Ming Lei
2016-12-27 15:56 ` [PATCH v1 16/54] block: introduce bio_for_each_segment_mp() Ming Lei
2016-12-27 15:56 ` [PATCH v1 17/54] block: introduce bio_clone_sp() Ming Lei
2016-12-27 15:56 ` [PATCH v1 18/54] bvec_iter: introduce BVEC_ITER_ALL_INIT Ming Lei
2016-12-27 15:56 ` [PATCH v1 19/54] block: bounce: avoid direct access to bvec table Ming Lei
2016-12-27 15:56 ` [PATCH v1 20/54] block: bounce: don't access bio->bi_io_vec in copy_to_high_bio_irq Ming Lei
2016-12-27 15:56 ` [PATCH v1 21/54] block: introduce bio_can_convert_to_sp() Ming Lei
2016-12-27 15:56 ` [PATCH v1 22/54] block: bounce: convert multipage bvecs into singlepage Ming Lei
2016-12-27 15:56 ` [PATCH v1 23/54] bcache: handle bio_clone() & bvec updating for multipage bvecs Ming Lei
2016-12-30 11:01 ` Coly Li
2016-12-31 10:29 ` Ming Lei
2016-12-27 15:56 ` Ming Lei [this message]
2016-12-27 15:56 ` [PATCH v1 25/54] block: blk-merge: try to make front segments in full size Ming Lei
2016-12-27 15:56 ` [PATCH v1 26/54] block: blk-merge: remove unnecessary check Ming Lei
2016-12-27 15:56 ` [PATCH v1 27/54] block: use bio_for_each_segment_mp() to compute segments count Ming Lei
2016-12-27 15:56 ` [PATCH v1 28/54] block: use bio_for_each_segment_mp() to map sg Ming Lei
2016-12-27 15:56 ` [PATCH v1 29/54] block: introduce bvec_for_each_sp_bvec() Ming Lei
2016-12-27 15:56 ` [PATCH v1 30/54] block: bio: introduce single/multi page version of bio_for_each_segment_all() Ming Lei
2016-12-27 15:56 ` [PATCH v1 31/54] block: introduce bio_segments_all() Ming Lei
2017-01-16 3:19 ` [PATCH v1 00/54] block: support multipage bvec Ming Lei
2017-01-16 15:18 ` Christoph Hellwig
2017-01-17 2:40 ` Ming Lei
2017-01-17 7:50 ` Christoph Hellwig
2017-01-17 8:13 ` Ming Lei
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