On Fri, Aug 04, 2017 at 09:04:20AM -0600, Jens Axboe wrote:
> We don't have to inc/dec some counter, since we can just
> iterate the tags. That makes inc/dec a noop, but means we
> have to iterate busy tags to get an in-flight count.
>
> Reviewed-by: Bart Van Assche <bart.vanassche@xxxxxxx>
Barring performance numbers that show that percpu is much better (which
I doubt),
Reviewed-by: Omar Sandoval <osandov@xxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
> block/blk-mq.c | 31 +++++++++++++++++++++++++++++++
> block/blk-mq.h | 3 +++
> block/genhd.c | 37 +++++++++++++++++++++++++++++++++++++
> include/linux/genhd.h | 34 ++++++----------------------------
> 4 files changed, 77 insertions(+), 28 deletions(-)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index a5d369dc7622..fe1aa1f5f069 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -83,6 +83,37 @@ static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
> sbitmap_clear_bit(&hctx->ctx_map, ctx->index_hw);
> }
>
> +struct mq_inflight {
> + struct hd_struct *part;
> + unsigned int *inflight;
> +};
> +
> +static void blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx,
> + struct request *rq, void *priv,
> + bool reserved)
> +{
> + struct mq_inflight *mi = priv;
> +
> + if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
> + return;
> +
> + /*
> + * Count as inflight if it either matches the partition we asked
> + * for, or if it's the root
> + */
> + if (rq->part == mi->part || mi->part->partno)
> + mi->inflight[0]++;
> +}
> +
> +void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part,
> + unsigned int inflight[2])
> +{
> + struct mq_inflight mi = { .part = part, .inflight = inflight, };
> +
> + inflight[0] = 0;
> + blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
> +}
> +
> void blk_freeze_queue_start(struct request_queue *q)
> {
> int freeze_depth;
> diff --git a/block/blk-mq.h b/block/blk-mq.h
> index 60b01c0309bc..98252b79b80b 100644
> --- a/block/blk-mq.h
> +++ b/block/blk-mq.h
> @@ -133,4 +133,7 @@ static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx)
> return hctx->nr_ctx && hctx->tags;
> }
>
> +void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part,
> + unsigned int inflight[2]);
> +
> #endif
> diff --git a/block/genhd.c b/block/genhd.c
> index 822f65f95e2a..3dc4d115480f 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -45,6 +45,43 @@ static void disk_add_events(struct gendisk *disk);
> static void disk_del_events(struct gendisk *disk);
> static void disk_release_events(struct gendisk *disk);
>
> +void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
> +{
> + if (q->mq_ops)
> + return;
> +
> + atomic_inc(&part->in_flight[rw]);
> + if (part->partno)
> + atomic_inc(&part_to_disk(part)->part0.in_flight[rw]);
> +}
> +
> +void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
> +{
> + if (q->mq_ops)
> + return;
> +
> + atomic_dec(&part->in_flight[rw]);
> + if (part->partno)
> + atomic_dec(&part_to_disk(part)->part0.in_flight[rw]);
> +}
> +
> +void part_in_flight(struct request_queue *q, struct hd_struct *part,
> + unsigned int inflight[2])
> +{
> + if (q->mq_ops) {
> + blk_mq_in_flight(q, part, inflight);
> + return;
> + }
> +
> + inflight[0] = atomic_read(&part->in_flight[0]) +
> + atomic_read(&part->in_flight[1]);
> + if (part->partno) {
> + part = &part_to_disk(part)->part0;
> + inflight[1] = atomic_read(&part->in_flight[0]) +
> + atomic_read(&part->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 a9c8ea632fdc..ea652bfcd675 100644
> --- a/include/linux/genhd.h
> +++ b/include/linux/genhd.h
> @@ -362,34 +362,12 @@ static inline void free_part_stats(struct hd_struct *part)
> #define part_stat_sub(cpu, gendiskp, field, subnd) \
> part_stat_add(cpu, gendiskp, field, -subnd)
>
> -static inline void part_inc_in_flight(struct request_queue *q,
> - struct hd_struct *part, int rw)
> -{
> - atomic_inc(&part->in_flight[rw]);
> - if (part->partno)
> - atomic_inc(&part_to_disk(part)->part0.in_flight[rw]);
> -}
> -
> -static inline void part_dec_in_flight(struct request_queue *q,
> - struct hd_struct *part, int rw)
> -{
> - atomic_dec(&part->in_flight[rw]);
> - if (part->partno)
> - atomic_dec(&part_to_disk(part)->part0.in_flight[rw]);
> -}
> -
> -static inline void part_in_flight(struct request_queue *q,
> - struct hd_struct *part,
> - unsigned int inflight[2])
> -{
> - inflight[0] = atomic_read(&part->in_flight[0]) +
> - atomic_read(&part->in_flight[1]);
> - if (part->partno) {
> - part = &part_to_disk(part)->part0;
> - inflight[1] = atomic_read(&part->in_flight[0]) +
> - atomic_read(&part->in_flight[1]);
> - }
> -}
> +void part_in_flight(struct request_queue *q, struct hd_struct *part,
> + unsigned int inflight[2]);
> +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);
>
> static inline struct partition_meta_info *alloc_part_info(struct gendisk *disk)
> {
> --
> 2.7.4
>
