[PATCH 4/4] blk-mq: enable checking two part inflight counts at the same time

Jens Axboe
2017-08-03T20:01:56Z

We only need to iterate the queues and tags once, we if just pass
in both partition structs. Add part_in_flight_double() for
returning this value.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
block/blk-core.c | 34 +++++++++++++++++++++++-----------
block/blk-mq.c | 25 +++++++++++++++++--------
block/blk-mq.h | 3 ++-
block/genhd.c | 23 +++++++++++++++++++++--
include/linux/genhd.h | 2 ++
5 files changed, 65 insertions(+), 22 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index ba88d71b442f..d111a8f5bdf1 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1470,14 +1470,9 @@ static void add_acct_request(struct request_queue *q, struct request *rq,
}

static void part_round_stats_single(struct request_queue *q, int cpu,
- struct hd_struct *part, unsigned long now)
+ struct hd_struct *part, unsigned long now,
+ unsigned int inflight)
{
- int inflight;
-
- if (now == part->stamp)
- return;
-
- inflight = part_in_flight(q, part);
if (inflight) {
__part_stat_add(cpu, part, time_in_queue,
inflight * (now - part->stamp));
@@ -1505,12 +1500,29 @@ static void part_round_stats_single(struct request_queue *q, int cpu,
*/
void part_round_stats(struct request_queue *q, int cpu, struct hd_struct *part)
{
+ struct hd_struct *part2 = NULL;
unsigned long now = jiffies;
+ unsigned int inflight[2];
+ int stats = 0;
+
+ if (part->stamp != now)
+ stats |= 1;
+
+ if (part->partno) {
+ part2 = &part_to_disk(part)->part0;
+ if (part2->stamp != now)
+ stats |= 2;
+ }
+
+ if (!stats)
+ return;
+
+ part_in_flight_double(q, part, part2, inflight);

- if (part->partno)
- part_round_stats_single(q, cpu, &part_to_disk(part)->part0,
- now);
- part_round_stats_single(q, cpu, part, now);
+ if (stats & 2)
+ part_round_stats_single(q, cpu, part2, now, inflight[1]);
+ if (stats & 1)
+ part_round_stats_single(q, cpu, part, now, inflight[0]);
}
EXPORT_SYMBOL_GPL(part_round_stats);

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 37035891e120..03d164917160 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -87,8 +87,9 @@ static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
}

struct mq_inflight {
- struct hd_struct *part;
- unsigned int inflight;
+ struct hd_struct *part1;
+ struct hd_struct *part2;
+ unsigned int *inflight;
};

static void blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx,
@@ -97,17 +98,25 @@ static void blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx,
{
struct mq_inflight *mi = priv;

- if (rq->part == mi->part)
- mi->inflight++;
+ if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
+ return;
+ if (rq->part == mi->part1) {
+ mi->inflight[0]++;
+ if (mi->part1->partno &&
+ &part_to_disk(mi->part1)->part0 == mi->part2)
+ mi->inflight[1]++;
+ } else if (rq->part == mi->part2)
+ mi->inflight[1]++;
}

-unsigned int blk_mq_in_flight(struct request_queue *q,
- struct hd_struct *part)
+void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part1,
+ struct hd_struct *part2, unsigned int *inflight)
{
- struct mq_inflight mi = { .part = part, .inflight = 0 };
+ struct mq_inflight mi = { .part1 = part1, .part2 = part2,
+ .inflight = inflight };

+ inflight[0] = inflight[1] = 0;
blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
- return mi.inflight;
}

void blk_freeze_queue_start(struct request_queue *q)
diff --git a/block/blk-mq.h b/block/blk-mq.h
index cade1a512a01..c5264a64fb7c 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -138,6 +138,7 @@ static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx)
return hctx->nr_ctx && hctx->tags;
}

-unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part);
+void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part1,
+ struct hd_struct *part2, unsigned int *inflight);

#endif
diff --git a/block/genhd.c b/block/genhd.c
index ad5dc567d57f..6faacccd8453 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -67,13 +67,32 @@ void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, int rw)

int part_in_flight(struct request_queue *q, struct hd_struct *part)
{
- if (q->mq_ops)
- return blk_mq_in_flight(q, part);
+ if (q->mq_ops) {
+ unsigned int inflight[2];
+
+ blk_mq_in_flight(q, part, NULL, inflight);
+ return inflight[0];
+ }

return atomic_read(&part->in_flight[0]) +
atomic_read(&part->in_flight[1]);
}

+void part_in_flight_double(struct request_queue *q, struct hd_struct *part1,
+ struct hd_struct *part2, unsigned int *inflight)
+{
+ if (q->mq_ops) {
+ blk_mq_in_flight(q, part1, part2, inflight);
+ return;
+ }
+
+ inflight[0] = atomic_read(&part1->in_flight[0]) +
+ atomic_read(&part1->in_flight[1]);
+ if (part2) {
+ inflight[1] = atomic_read(&part2->in_flight[0]) +
+ atomic_read(&part2->in_flight[1]);
+ }
+}
/**
* disk_get_part - get partition
* @disk: disk to look partition from
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index f2c5096b3a7e..408690079143 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -363,6 +363,8 @@ static inline void free_part_stats(struct hd_struct *part)
part_stat_add(cpu, gendiskp, field, -subnd)

int part_in_flight(struct request_queue *q, struct hd_struct *part);
+void part_in_flight_double(struct request_queue *q, struct hd_struct *part1,
+ struct hd_struct *part2, unsigned int *inflight);
void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, int rw);
void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw);

--
2.7.4