On Thu 02-02-23 21:49:13, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
>
> After commit dfd6200a0954 ("blk-cgroup: support to track if policy is
> online"), there is no need to do this again in bfq.
>
> However, 'pd->online' is not protected by 'bfqd->lock', in order to make
> sure bfq won't see that 'pd->online' is still set after bfq_pd_offline(),
> clear it before bfq_pd_offline() is called. This is fine because other
> polices doesn't use 'pd->online' and bfq_pd_offline() will move active
> bfqq to root cgroup anyway.
>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
The patch looks good to me now. Thanks! Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> Changes in v3:
> - in commit message: protected -> not protected, bfq_pd_offline_() ->
> bfq_pd_offline().
> Changes in v2:
> - clear 'pd->online' before calling bfq_pd_offline()
>
> block/bfq-cgroup.c | 4 +---
> block/bfq-iosched.h | 2 --
> block/blk-cgroup.c | 2 +-
> 3 files changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
> index b42956ab5550..a35136dae713 100644
> --- a/block/bfq-cgroup.c
> +++ b/block/bfq-cgroup.c
> @@ -551,7 +551,6 @@ static void bfq_pd_init(struct blkg_policy_data *pd)
> bfqg->bfqd = bfqd;
> bfqg->active_entities = 0;
> bfqg->num_queues_with_pending_reqs = 0;
> - bfqg->online = true;
> bfqg->rq_pos_tree = RB_ROOT;
> }
>
> @@ -614,7 +613,7 @@ struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio)
> continue;
> }
> bfqg = blkg_to_bfqg(blkg);
> - if (bfqg->online) {
> + if (bfqg->pd.online) {
> bio_associate_blkg_from_css(bio, &blkg->blkcg->css);
> return bfqg;
> }
> @@ -985,7 +984,6 @@ static void bfq_pd_offline(struct blkg_policy_data *pd)
>
> put_async_queues:
> bfq_put_async_queues(bfqd, bfqg);
> - bfqg->online = false;
>
> spin_unlock_irqrestore(&bfqd->lock, flags);
> /*
> diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
> index 75cc6a324267..69aaee52285a 100644
> --- a/block/bfq-iosched.h
> +++ b/block/bfq-iosched.h
> @@ -1009,8 +1009,6 @@ struct bfq_group {
>
> /* reference counter (see comments in bfq_bic_update_cgroup) */
> refcount_t ref;
> - /* Is bfq_group still online? */
> - bool online;
>
> struct bfq_entity entity;
> struct bfq_sched_data sched_data;
> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> index cb110fc51940..a228dfe65253 100644
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -491,9 +491,9 @@ static void blkg_destroy(struct blkcg_gq *blkg)
> struct blkcg_policy *pol = blkcg_policy[i];
>
> if (blkg->pd[i] && blkg->pd[i]->online) {
> + blkg->pd[i]->online = false;
> if (pol->pd_offline_fn)
> pol->pd_offline_fn(blkg->pd[i]);
> - blkg->pd[i]->online = false;
> }
> }
>
> --
> 2.31.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
