From: Jan Kara <jack@suse.cz>
To: Yu Kuai <yukuai3@huawei.com>
Cc: jack@suse.cz, paolo.valente@linaro.org, axboe@kernel.dk,
tj@kernel.org, linux-block@vger.kernel.org,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
yi.zhang@huawei.com
Subject: Re: [PATCH -next v2 2/5] block, bfq: add fake weight_counter for weight-raised queue
Date: Mon, 25 Apr 2022 11:48:56 +0200 [thread overview]
Message-ID: <20220425094856.qgkhba2klguduxot@quack3.lan> (raw)
In-Reply-To: <20220416093753.3054696-3-yukuai3@huawei.com>
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@huawei.com>
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@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2022-04-25 9:50 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-16 9:37 [PATCH -next v2 0/5] support concurrent sync io for bfq on a specail occasion Yu Kuai
2022-04-16 9:37 ` [PATCH -next v2 1/5] block, bfq: cleanup bfq_weights_tree add/remove apis Yu Kuai
2022-04-25 9:37 ` Jan Kara
2022-04-16 9:37 ` [PATCH -next v2 2/5] block, bfq: add fake weight_counter for weight-raised queue Yu Kuai
2022-04-25 9:48 ` Jan Kara [this message]
2022-04-25 13:34 ` yukuai (C)
2022-04-25 13:55 ` yukuai (C)
2022-04-25 16:26 ` Jan Kara
2022-04-25 16:16 ` Jan Kara
2022-04-26 1:49 ` yukuai (C)
2022-04-26 7:40 ` Jan Kara
2022-04-26 8:27 ` yukuai (C)
2022-04-26 9:15 ` Jan Kara
2022-04-26 11:27 ` yukuai (C)
2022-04-26 14:04 ` Paolo Valente
2022-04-16 9:37 ` [PATCH -next v2 3/5] bfq, block: record how many queues have pending requests in bfq_group Yu Kuai
2022-04-16 9:37 ` [PATCH -next v2 4/5] block, bfq: refactor the counting of 'num_groups_with_pending_reqs' Yu Kuai
2022-04-16 9:37 ` [PATCH -next v2 5/5] block, bfq: do not idle if only one cgroup is activated Yu Kuai
2022-04-24 2:44 ` [PATCH -next v2 0/5] support concurrent sync io for bfq on a specail occasion yukuai (C)
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