On Sat 16-04-22 17:37:50, Yu Kuai wrote:
> Weight-raised queue is not inserted to weights_tree, which makes it
> impossible to track how many queues have pending requests through
> weights_tree insertion and removel. This patch add fake weight_counter
> for weight-raised queue to do that.
>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
This is a bit hacky. I was looking into a better place where to hook to
count entities in a bfq_group with requests and I think bfq_add_bfqq_busy()
and bfq_del_bfqq_busy() are ideal for this. It also makes better sense
conceptually than hooking into weights tree handling.
Other than this the rest of the series looks fine to me.
Honza
> ---
> block/bfq-iosched.c | 11 +++++++++++
> block/bfq-wf2q.c | 5 ++---
> 2 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
> index 2deea2d07a1f..a2977c938c70 100644
> --- a/block/bfq-iosched.c
> +++ b/block/bfq-iosched.c
> @@ -134,6 +134,8 @@
> #include "bfq-iosched.h"
> #include "blk-wbt.h"
>
> +#define BFQ_FAKE_WEIGHT_COUNTER ((void *) POISON_INUSE)
> +
> #define BFQ_BFQQ_FNS(name) \
> void bfq_mark_bfqq_##name(struct bfq_queue *bfqq) \
> { \
> @@ -884,6 +886,12 @@ void bfq_weights_tree_add(struct bfq_data *bfqd, struct bfq_queue *bfqq)
> if (bfqq->weight_counter)
> return;
>
> + if (bfqq->wr_coeff != 1) {
> + bfqq->weight_counter = BFQ_FAKE_WEIGHT_COUNTER;
> + bfqq->ref++;
> + return;
> + }
> +
> while (*new) {
> struct bfq_weight_counter *__counter = container_of(*new,
> struct bfq_weight_counter,
> @@ -943,6 +951,9 @@ void __bfq_weights_tree_remove(struct bfq_data *bfqd, struct bfq_queue *bfqq)
> if (!bfqq->weight_counter)
> return;
>
> + if (bfqq->weight_counter == BFQ_FAKE_WEIGHT_COUNTER)
> + goto reset_entity_pointer;
> +
> root = &bfqd->queue_weights_tree;
> bfqq->weight_counter->num_active--;
> if (bfqq->weight_counter->num_active > 0)
> diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
> index a1296058c1ec..ae12c6b2c525 100644
> --- a/block/bfq-wf2q.c
> +++ b/block/bfq-wf2q.c
> @@ -776,7 +776,7 @@ __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st,
> * Add the entity, if it is not a weight-raised queue,
> * to the counter associated with its new weight.
> */
> - if (prev_weight != new_weight && bfqq && bfqq->wr_coeff == 1)
> + if (prev_weight != new_weight && bfqq)
> bfq_weights_tree_add(bfqd, bfqq);
>
> new_st->wsum += entity->weight;
> @@ -1680,8 +1680,7 @@ void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq)
> bfqd->busy_queues[bfqq->ioprio_class - 1]++;
>
> if (!bfqq->dispatched)
> - if (bfqq->wr_coeff == 1)
> - bfq_weights_tree_add(bfqd, bfqq);
> + bfq_weights_tree_add(bfqd, bfqq);
>
> if (bfqq->wr_coeff > 1)
> bfqd->wr_busy_queues++;
> --
> 2.31.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
