From: Jens Axboe <axboe@kernel.dk>
To: Paolo Valente <paolo.valente@linaro.org>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
bfq-iosched@googlegroups.com, oleksandr@natalenko.name,
patdung100@gmail.com, cevich@redhat.com
Subject: Re: [PATCH BUGFIX 5/6] block, bfq: get a ref to a group when adding it to a service tree
Date: Fri, 31 Jan 2020 21:44:21 -0700 [thread overview]
Message-ID: <0572f01d-ab0a-b89e-a5d4-6ddf2d3db18e@kernel.dk> (raw)
In-Reply-To: <20200131092409.10867-6-paolo.valente@linaro.org>
On 1/31/20 2:24 AM, Paolo Valente wrote:
> BFQ schedules generic entities, which may represent either bfq_queues
> or groups of bfq_queues. When an entity is inserted into a service
> tree, a reference must be taken, to make sure that the entity does not
> disappear while still referred in the tree. Unfortunately, such a
> reference is mistakenly taken only if the entity represents a
> bfq_queue. This commit takes a reference also in case the entity
> represents a group.
>
> Tested-by: Chris Evich <cevich@redhat.com>
> Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
> ---
> block/bfq-cgroup.c | 2 +-
> block/bfq-iosched.h | 1 +
> block/bfq-wf2q.c | 16 +++++++++++++++-
> 3 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
> index c818c64766e5..f85b25fd06f2 100644
> --- a/block/bfq-cgroup.c
> +++ b/block/bfq-cgroup.c
> @@ -332,7 +332,7 @@ static void bfqg_put(struct bfq_group *bfqg)
> kfree(bfqg);
> }
>
> -static void bfqg_and_blkg_get(struct bfq_group *bfqg)
> +void bfqg_and_blkg_get(struct bfq_group *bfqg)
> {
> /* see comments in bfq_bic_update_cgroup for why refcounting bfqg */
> bfqg_get(bfqg);
> diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
> index f1cb89def7f8..b9627ec7007b 100644
> --- a/block/bfq-iosched.h
> +++ b/block/bfq-iosched.h
> @@ -984,6 +984,7 @@ struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd,
> struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg);
> struct bfq_group *bfqq_group(struct bfq_queue *bfqq);
> struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node);
> +void bfqg_and_blkg_get(struct bfq_group *bfqg);
> void bfqg_and_blkg_put(struct bfq_group *bfqg);
>
> #ifdef CONFIG_BFQ_GROUP_IOSCHED
> diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c
> index 26776bdbdf36..ef06e0d34b5b 100644
> --- a/block/bfq-wf2q.c
> +++ b/block/bfq-wf2q.c
> @@ -533,7 +533,13 @@ static void bfq_get_entity(struct bfq_entity *entity)
> bfqq->ref++;
> bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d",
> bfqq, bfqq->ref);
> +#ifdef CONFIG_BFQ_GROUP_IOSCHED
> + } else
> + bfqg_and_blkg_get(container_of(entity, struct bfq_group,
> + entity));
> +#else
> }
> +#endif
These are really an eyesore and needs improving. Surely that can be done
in a cleaner way?
--
Jens Axboe
next prev parent reply other threads:[~2020-02-01 4:44 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-31 9:24 [PATCH BUGFIX 0/6] block, bfq: series of fixes, and not only, for some recently reported issues Paolo Valente
2020-01-31 9:24 ` [PATCH BUGFIX 1/6] block, bfq: do not plug I/O for bfq_queues with no proc refs Paolo Valente
2020-01-31 9:24 ` [PATCH BUGFIX 2/6] block, bfq: do not insert oom queue into position tree Paolo Valente
2020-01-31 9:24 ` [PATCH BUGFIX 3/6] block, bfq: get extra ref to prevent a queue from being freed during a group move Paolo Valente
2020-01-31 10:20 ` Oleksandr Natalenko
2020-01-31 10:41 ` Paolo Valente
2020-01-31 9:24 ` [PATCH BUGFIX 4/6] block, bfq: extend incomplete name of field on_st Paolo Valente
2020-01-31 9:24 ` [PATCH BUGFIX 5/6] block, bfq: get a ref to a group when adding it to a service tree Paolo Valente
2020-02-01 4:44 ` Jens Axboe [this message]
2020-01-31 9:24 ` [PATCH BUGFIX 6/6] block, bfq: clarify the goal of bfq_split_bfqq() Paolo Valente
2020-02-01 4:48 ` [PATCH BUGFIX 0/6] block, bfq: series of fixes, and not only, for some recently reported issues Jens Axboe
2020-02-03 8:50 ` Paolo Valente
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