> Il giorno 23 mag 2022, alle ore 15:18, Yu Kuai <yukuai3@xxxxxxxxxx> ha scritto:
>
> Prepare to refactor the counting of 'num_groups_with_pending_reqs'.
>
> Add a counter 'busy_queues' in bfq_group, and update it in
> bfq_add/del_bfqq_busy().
>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> Reviewed-by: Jan Kara <jack@xxxxxxx>
> ---
> block/bfq-cgroup.c | 1 +
> block/bfq-iosched.h | 2 ++
> block/bfq-wf2q.c | 20 ++++++++++++++++++++
> 3 files changed, 23 insertions(+)
>
> diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
> index 09574af83566..4d516879d9fa 100644
> --- a/block/bfq-cgroup.c
> +++ b/block/bfq-cgroup.c
> @@ -557,6 +557,7 @@ static void bfq_pd_init(struct blkg_policy_data *pd)
> */
> bfqg->bfqd = bfqd;
> bfqg->active_entities = 0;
> + bfqg->busy_queues = 0;
> bfqg->online = true;
> bfqg->rq_pos_tree = RB_ROOT;
> }
> diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
> index 978ef5d6fe6a..3847f4ab77ac 100644
> --- a/block/bfq-iosched.h
> +++ b/block/bfq-iosched.h
> @@ -906,6 +906,7 @@ struct bfq_group_data {
> * are groups with more than one active @bfq_entity
> * (see the comments to the function
> * bfq_bfqq_may_idle()).
> + * @busy_queues: number of busy bfqqs.
> * @rq_pos_tree: rbtree sorted by next_request position, used when
> * determining if two or more queues have interleaving
> * requests (see bfq_find_close_cooperator()).
> @@ -942,6 +943,7 @@ struct bfq_group {
> struct bfq_entity *my_entity;
>
> int active_entities;
> + int busy_queues;
>
> struct rb_root rq_pos_tree;
>
> diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
> index f8eb340381cf..d9ff33e0be38 100644
> --- a/block/bfq-wf2q.c
> +++ b/block/bfq-wf2q.c
> @@ -218,6 +218,16 @@ static bool bfq_no_longer_next_in_service(struct bfq_entity *entity)
> return false;
> }
>
> +static void bfq_inc_busy_queues(struct bfq_queue *bfqq)
> +{
> + bfqq_group(bfqq)->busy_queues++;
> +}
> +
> +static void bfq_dec_busy_queues(struct bfq_queue *bfqq)
> +{
> + bfqq_group(bfqq)->busy_queues--;
> +}
> +
> #else /* CONFIG_BFQ_GROUP_IOSCHED */
>
> static bool bfq_update_parent_budget(struct bfq_entity *next_in_service)
> @@ -230,6 +240,14 @@ static bool bfq_no_longer_next_in_service(struct bfq_entity *entity)
> return true;
> }
>
> +static void bfq_inc_busy_queues(struct bfq_queue *bfqq)
> +{
> +}
> +
> +static void bfq_dec_busy_queues(struct bfq_queue *bfqq)
> +{
> +}
> +
> #endif /* CONFIG_BFQ_GROUP_IOSCHED */
>
> /*
> @@ -1660,6 +1678,7 @@ void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq,
> bfq_clear_bfqq_busy(bfqq);
>
> bfqd->busy_queues[bfqq->ioprio_class - 1]--;
> + bfq_inc_busy_queues(bfqq);
>
Why do you increment the number of busy queues for the group on a
del_bfqq_busy, instead of an add_bfqq_busy?
Besides, the name of the function bfq_inc_busy_queues does not mention
the target of the update, namely the group. This creates a little
confusion at a first sight, as one sees this function invoked right
after the update of a field with the same name: bfqd->busy_queues.
> if (bfqq->wr_coeff > 1)
> bfqd->wr_busy_queues--;
> @@ -1683,6 +1702,7 @@ void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq)
>
> bfq_mark_bfqq_busy(bfqq);
> bfqd->busy_queues[bfqq->ioprio_class - 1]++;
> + bfq_dec_busy_queues(bfqq);
Same pair of comments as above.
Thanks,
Paolo
>
> if (!bfqq->dispatched)
> if (bfqq->wr_coeff == 1)
> --
> 2.31.1
>
