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Date: Mon, 04 May 2020 16:31:04 +0300
From: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
To: linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
Jens Axboe <axboe@...nel.dk>
Subject: [PATCH 4/4] block/part_stat: add helper blk_account_io_merge_bio()
Move non-"new_io" branch of blk_account_io_start() into separate function.
Fix merge accounting for discards (they were counted as write merges).
Also blk_account_io_merge_bio() doesn't call update_io_ticks() unlike to
blk_account_io_start(), there is no reason for that.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
---
block/blk-core.c | 39 ++++++++++++++++++++++-----------------
block/blk-exec.c | 2 +-
block/blk-mq.c | 2 +-
block/blk.h | 2 +-
4 files changed, 25 insertions(+), 20 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 45ddf7238c06..18fb42eb2f18 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -622,6 +622,17 @@ void blk_put_request(struct request *req)
}
EXPORT_SYMBOL(blk_put_request);
+static void blk_account_io_merge_bio(struct request *req)
+{
+ if (blk_do_io_stat(req)) {
+ const int sgrp = op_stat_group(req_op(req));
+
+ part_stat_lock();
+ part_stat_inc(req->part, merges[sgrp]);
+ part_stat_unlock();
+ }
+}
+
bool bio_attempt_back_merge(struct request *req, struct bio *bio,
unsigned int nr_segs)
{
@@ -640,7 +651,7 @@ bool bio_attempt_back_merge(struct request *req, struct bio *bio,
req->biotail = bio;
req->__data_len += bio->bi_iter.bi_size;
- blk_account_io_start(req, false);
+ blk_account_io_merge_bio(req);
return true;
}
@@ -664,7 +675,7 @@ bool bio_attempt_front_merge(struct request *req, struct bio *bio,
req->__sector = bio->bi_iter.bi_sector;
req->__data_len += bio->bi_iter.bi_size;
- blk_account_io_start(req, false);
+ blk_account_io_merge_bio(req);
return true;
}
@@ -686,7 +697,7 @@ bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
req->__data_len += bio->bi_iter.bi_size;
req->nr_phys_segments = segments + 1;
- blk_account_io_start(req, false);
+ blk_account_io_merge_bio(req);
return true;
no_merge:
req_set_nomerge(q, req);
@@ -1258,7 +1269,7 @@ blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *
return BLK_STS_IOERR;
if (blk_queue_io_stat(q))
- blk_account_io_start(rq, true);
+ blk_account_io_start(rq);
/*
* Since we have a scheduler attached on the top device,
@@ -1348,20 +1359,14 @@ void blk_account_io_done(struct request *req, u64 now)
}
}
-void blk_account_io_start(struct request *rq, bool new_io)
+void blk_account_io_start(struct request *rq)
{
struct hd_struct *part;
int rw = rq_data_dir(rq);
- if (!blk_do_io_stat(rq))
- return;
-
- part_stat_lock();
+ if (blk_do_io_stat(rq)) {
+ part_stat_lock();
- if (!new_io) {
- part = rq->part;
- part_stat_inc(part, merges[rw]);
- } else {
rcu_read_lock();
part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
if (!hd_struct_try_get(part)) {
@@ -1378,13 +1383,13 @@ void blk_account_io_start(struct request *rq, bool new_io)
}
rcu_read_unlock();
- part_inc_in_flight(rq->q, part, rw);
rq->part = part;
- }
- update_io_ticks(part, jiffies, false);
+ part_inc_in_flight(rq->q, part, rw);
+ update_io_ticks(part, jiffies, false);
- part_stat_unlock();
+ part_stat_unlock();
+ }
}
/*
diff --git a/block/blk-exec.c b/block/blk-exec.c
index e20a852ae432..85324d53d072 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -55,7 +55,7 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
rq->rq_disk = bd_disk;
rq->end_io = done;
- blk_account_io_start(rq, true);
+ blk_account_io_start(rq);
/*
* don't check dying flag for MQ because the request won't
diff --git a/block/blk-mq.c b/block/blk-mq.c
index bcc3a2397d4a..049c4f9417c3 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1794,7 +1794,7 @@ static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
rq->write_hint = bio->bi_write_hint;
blk_rq_bio_prep(rq, bio, nr_segs);
- blk_account_io_start(rq, true);
+ blk_account_io_start(rq);
}
static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
diff --git a/block/blk.h b/block/blk.h
index 73bd3b1c6938..06cd57cc10fb 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -195,7 +195,7 @@ bool bio_attempt_discard_merge(struct request_queue *q, struct request *req,
bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
unsigned int nr_segs, struct request **same_queue_rq);
-void blk_account_io_start(struct request *req, bool new_io);
+void blk_account_io_start(struct request *req);
void blk_account_io_completion(struct request *req, unsigned int bytes);
void blk_account_io_done(struct request *req, u64 now);
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