From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Theodore Ts'o <tytso@mit.edu>,
Omar Sandoval <osandov@fb.com>, Sagi Grimberg <sagi@grimberg.me>,
Dave Chinner <dchinner@redhat.com>,
Kent Overstreet <kent.overstreet@gmail.com>,
Mike Snitzer <snitzer@redhat.com>,
dm-devel@redhat.com, Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-raid@vger.kernel.org,
David Sterba <dsterba@suse.com>,
linux-btrfs@vger.kernel.org,
"Darrick J . Wong" <darrick.wong@oracle.com>,
linux-xfs@vger.kernel.org, Gao Xiang <gaoxiang25@huawei.com>,
Christoph Hellwig <hch@lst.de>,
linux-ext4@vger.kernel.org, Coly Li <colyli@suse.de>,
linux-bcache@vger.kernel.org, Boaz Harrosh <ooo@electrozaur.com>,
Bob Peterson <rpeterso@redhat.com>,
cluster-devel@redhat.com, Ming Lei <ming.lei@redhat.com>
Subject: [PATCH V15 17/18] block: kill QUEUE_FLAG_NO_SG_MERGE
Date: Fri, 15 Feb 2019 19:13:23 +0800 [thread overview]
Message-ID: <20190215111324.30129-18-ming.lei@redhat.com> (raw)
In-Reply-To: <20190215111324.30129-1-ming.lei@redhat.com>
Since bdced438acd83ad83a6c ("block: setup bi_phys_segments after splitting"),
physical segment number is mainly figured out in blk_queue_split() for
fast path, and the flag of BIO_SEG_VALID is set there too.
Now only blk_recount_segments() and blk_recalc_rq_segments() use this
flag.
Basically blk_recount_segments() is bypassed in fast path given BIO_SEG_VALID
is set in blk_queue_split().
For another user of blk_recalc_rq_segments():
- run in partial completion branch of blk_update_request, which is an unusual case
- run in blk_cloned_rq_check_limits(), still not a big problem if the flag is killed
since dm-rq is the only user.
Multi-page bvec is enabled now, not doing S/G merging is rather pointless with the
current setup of the I/O path, as it isn't going to save you a significant amount
of cycles.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/blk-merge.c | 31 ++++++-------------------------
block/blk-mq-debugfs.c | 1 -
block/blk-mq.c | 3 ---
drivers/md/dm-table.c | 13 -------------
include/linux/blkdev.h | 1 -
5 files changed, 6 insertions(+), 43 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 1912499b08b7..bed065904677 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -358,8 +358,7 @@ void blk_queue_split(struct request_queue *q, struct bio **bio)
EXPORT_SYMBOL(blk_queue_split);
static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
- struct bio *bio,
- bool no_sg_merge)
+ struct bio *bio)
{
struct bio_vec bv, bvprv = { NULL };
int prev = 0;
@@ -385,13 +384,6 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
nr_phys_segs = 0;
for_each_bio(bio) {
bio_for_each_bvec(bv, bio, iter) {
- /*
- * If SG merging is disabled, each bio vector is
- * a segment
- */
- if (no_sg_merge)
- goto new_segment;
-
if (prev) {
if (seg_size + bv.bv_len
> queue_max_segment_size(q))
@@ -421,27 +413,16 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
void blk_recalc_rq_segments(struct request *rq)
{
- bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE,
- &rq->q->queue_flags);
-
- rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio,
- no_sg_merge);
+ rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio);
}
void blk_recount_segments(struct request_queue *q, struct bio *bio)
{
- unsigned short seg_cnt = bio_segments(bio);
-
- if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags) &&
- (seg_cnt < queue_max_segments(q)))
- bio->bi_phys_segments = seg_cnt;
- else {
- struct bio *nxt = bio->bi_next;
+ struct bio *nxt = bio->bi_next;
- bio->bi_next = NULL;
- bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, false);
- bio->bi_next = nxt;
- }
+ bio->bi_next = NULL;
+ bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio);
+ bio->bi_next = nxt;
bio_set_flag(bio, BIO_SEG_VALID);
}
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index c782e81db627..697d6213c82b 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -128,7 +128,6 @@ static const char *const blk_queue_flag_name[] = {
QUEUE_FLAG_NAME(SAME_FORCE),
QUEUE_FLAG_NAME(DEAD),
QUEUE_FLAG_NAME(INIT_DONE),
- QUEUE_FLAG_NAME(NO_SG_MERGE),
QUEUE_FLAG_NAME(POLL),
QUEUE_FLAG_NAME(WC),
QUEUE_FLAG_NAME(FUA),
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 44d471ff8754..fa508ee31742 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2837,9 +2837,6 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
set->map[HCTX_TYPE_POLL].nr_queues)
blk_queue_flag_set(QUEUE_FLAG_POLL, q);
- if (!(set->flags & BLK_MQ_F_SG_MERGE))
- blk_queue_flag_set(QUEUE_FLAG_NO_SG_MERGE, q);
-
q->sg_reserved_size = INT_MAX;
INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 4b1be754cc41..ba9481f1bf3c 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1698,14 +1698,6 @@ static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
return q && !blk_queue_add_random(q);
}
-static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
- sector_t start, sector_t len, void *data)
-{
- struct request_queue *q = bdev_get_queue(dev->bdev);
-
- return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
-}
-
static bool dm_table_all_devices_attribute(struct dm_table *t,
iterate_devices_callout_fn func)
{
@@ -1902,11 +1894,6 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
if (!dm_table_supports_write_zeroes(t))
q->limits.max_write_zeroes_sectors = 0;
- if (dm_table_all_devices_attribute(t, queue_supports_sg_merge))
- blk_queue_flag_clear(QUEUE_FLAG_NO_SG_MERGE, q);
- else
- blk_queue_flag_set(QUEUE_FLAG_NO_SG_MERGE, q);
-
dm_table_verify_integrity(t);
/*
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index b6292d469ea4..faed9d9eb84c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -588,7 +588,6 @@ struct request_queue {
#define QUEUE_FLAG_SAME_FORCE 12 /* force complete on same CPU */
#define QUEUE_FLAG_DEAD 13 /* queue tear-down finished */
#define QUEUE_FLAG_INIT_DONE 14 /* queue is initialized */
-#define QUEUE_FLAG_NO_SG_MERGE 15 /* don't attempt to merge SG segments*/
#define QUEUE_FLAG_POLL 16 /* IO polling enabled if set */
#define QUEUE_FLAG_WC 17 /* Write back caching */
#define QUEUE_FLAG_FUA 18 /* device supports FUA writes */
--
2.9.5
next prev parent reply other threads:[~2019-02-15 11:18 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-15 11:13 [PATCH V15 00/18] block: support multi-page bvec Ming Lei
2019-02-15 11:13 ` [PATCH V15 01/18] btrfs: look at bi_size for repair decisions Ming Lei
2019-02-15 11:13 ` [PATCH V15 02/18] block: don't use bio->bi_vcnt to figure out segment number Ming Lei
2019-02-15 11:13 ` [PATCH V15 03/18] block: remove bvec_iter_rewind() Ming Lei
2019-02-15 11:13 ` [PATCH V15 04/18] block: introduce multi-page bvec helpers Ming Lei
2019-02-15 11:13 ` [PATCH V15 05/18] block: introduce bio_for_each_bvec() and rq_for_each_bvec() Ming Lei
2019-02-15 11:13 ` [PATCH V15 06/18] block: use bio_for_each_bvec() to compute multi-page bvec count Ming Lei
2019-02-15 11:13 ` [PATCH V15 07/18] block: use bio_for_each_bvec() to map sg Ming Lei
2019-02-15 11:13 ` [PATCH V15 08/18] block: introduce mp_bvec_last_segment() Ming Lei
2019-02-15 11:13 ` [PATCH V15 09/18] fs/buffer.c: use bvec iterator to truncate the bio Ming Lei
2019-02-15 11:13 ` [PATCH V15 10/18] btrfs: use mp_bvec_last_segment to get bio's last page Ming Lei
2019-02-15 11:13 ` [PATCH V15 11/18] block: loop: pass multi-page bvec to iov_iter Ming Lei
2019-02-15 11:13 ` [PATCH V15 12/18] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages() Ming Lei
2019-02-15 11:13 ` [PATCH V15 13/18] block: allow bio_for_each_segment_all() to iterate over multi-page bvec Ming Lei
2019-02-15 11:13 ` [PATCH V15 14/18] block: enable multipage bvecs Ming Lei
[not found] ` <CGME20190221084301eucas1p11e8841a62b4b1da3cccca661b6f4c29d@eucas1p1.samsung.com>
2019-02-21 8:42 ` Marek Szyprowski
2019-02-21 9:57 ` Ming Lei
2019-02-21 10:08 ` Marek Szyprowski
2019-02-21 10:16 ` Ming Lei
2019-02-21 10:22 ` Marek Szyprowski
2019-02-21 10:38 ` Ming Lei
2019-02-21 11:42 ` Marek Szyprowski
2019-02-27 20:47 ` Jon Hunter
2019-02-27 23:29 ` Ming Lei
2019-02-28 7:51 ` Marek Szyprowski
2019-02-28 12:39 ` Jon Hunter
2019-02-15 11:13 ` [PATCH V15 15/18] block: always define BIO_MAX_PAGES as 256 Ming Lei
2019-02-15 11:13 ` [PATCH V15 16/18] block: document usage of bio iterator helpers Ming Lei
2019-02-15 11:13 ` Ming Lei [this message]
2019-02-15 11:13 ` [PATCH V15 18/18] block: kill BLK_MQ_F_SG_MERGE Ming Lei
2019-02-15 14:51 ` [PATCH V15 00/18] block: support multi-page bvec Christoph Hellwig
2019-02-17 13:10 ` Ming Lei
2019-02-15 15:49 ` Jens Axboe
2019-02-15 17:14 ` [dm-devel] " Bart Van Assche
2019-02-15 17:59 ` Jens Axboe
2019-02-17 13:13 ` Ming Lei
2019-02-18 7:49 ` Ming Lei
2019-02-17 13:11 ` Ming Lei
2019-02-19 16:28 ` Bart Van Assche
2019-02-20 1:17 ` Ming Lei
2019-02-20 2:37 ` Bart Van Assche
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190215111324.30129-18-ming.lei@redhat.com \
--to=ming.lei@redhat.com \
--cc=axboe@kernel.dk \
--cc=cluster-devel@redhat.com \
--cc=colyli@suse.de \
--cc=darrick.wong@oracle.com \
--cc=dchinner@redhat.com \
--cc=dm-devel@redhat.com \
--cc=dsterba@suse.com \
--cc=gaoxiang25@huawei.com \
--cc=hch@lst.de \
--cc=kent.overstreet@gmail.com \
--cc=linux-bcache@vger.kernel.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-raid@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=ooo@electrozaur.com \
--cc=osandov@fb.com \
--cc=rpeterso@redhat.com \
--cc=sagi@grimberg.me \
--cc=snitzer@redhat.com \
--cc=tytso@mit.edu \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).