Messages in this thread | | | Subject | Re: [PATCH v2 1/4] block, bfq: add support to track if root_group have any pending requests | From | "yukuai (C)" <> | Date | Thu, 2 Sep 2021 21:23:07 +0800 |
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On 2021/08/27 1:00, Paolo Valente wrote: > > >> Il giorno 6 ago 2021, alle ore 04:08, Yu Kuai <yukuai3@huawei.com> ha scritto: >> >> Add a new member in bfq_data to track number of queues that are in >> root_group with any pending requests. > > maybe modify the last part of the sentence as: ... and that have some pending request > >> This will be used in next patch >> to optmize queue idle judgment when root_group doesn't have any >> pending requests. >> >> Signed-off-by: Yu Kuai <yukuai3@huawei.com> >> --- >> block/bfq-iosched.c | 8 +++++++- >> block/bfq-iosched.h | 13 +++++++++++-- >> block/bfq-wf2q.c | 37 ++++++++++++++++++++++++------------- >> 3 files changed, 42 insertions(+), 16 deletions(-) >> >> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c >> index 727955918563..7c6b412f9a9c 100644 >> --- a/block/bfq-iosched.c >> +++ b/block/bfq-iosched.c >> @@ -859,8 +859,14 @@ void __bfq_weights_tree_remove(struct bfq_data *bfqd, >> void bfq_weights_tree_remove(struct bfq_data *bfqd, >> struct bfq_queue *bfqq) >> { >> - struct bfq_entity *entity = bfqq->entity.parent; >> + struct bfq_entity *entity = &bfqq->entity; >> + >> + if (entity->in_groups_with_pending_reqs) { >> + entity->in_groups_with_pending_reqs = false; >> + bfqd->num_queues_with_pending_reqs_in_root--; > > Here you cross the comment "The decrement of > num_groups_with_pending_reqs is not performed immediately upon ...". > > Find a way to > - move that comment up, and to make it correct for this slightly > different decrement > - leave a correct comment (probably shorter) in the original position > >> + } >> >> + entity = entity->parent; >> for_each_entity(entity) { >> struct bfq_sched_data *sd = entity->my_sched_data; >> >> diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h >> index 99c2a3cb081e..610769214f72 100644 >> --- a/block/bfq-iosched.h >> +++ b/block/bfq-iosched.h >> @@ -195,7 +195,12 @@ struct bfq_entity { >> /* flag, set to request a weight, ioprio or ioprio_class change */ >> int prio_changed; >> >> - /* flag, set if the entity is counted in groups_with_pending_reqs */ >> + /* >> + * If entity represents bfq_group, this flag will set > > will be set? > >> if the group is >> + * not root_group and have > > has > >> any pending requests; If entity represents > > one more nit: use lowercase after semicolon > >> + * bfq_queue, this flag will set > > will be set > >> if the queue is in root_group and have >> + * any pending requests. >> + */ >> bool in_groups_with_pending_reqs; >> > > The name of the above field follows from the fact that entity is > counted in groups_with_pending_reqs. You change this fact, because, > in your patch, a queue is not counted in groups_with_pending_reqs. > But you leave the same name. This creates confusion. > > >> /* last child queue of entity created (for non-leaf entities) */ >> @@ -539,7 +544,11 @@ struct bfq_data { >> * with no request waiting for completion. >> */ >> unsigned int num_groups_with_pending_reqs; >> - >> + /* >> + * number of queues that are in root_group with at least one request >> + * waiting for completion. > > please link somehow this comment to the long comment that comes before it > >> + */ >> + unsigned int num_queues_with_pending_reqs_in_root; > > Why using two counters? I mean, couldn't you simply count also the > root group in num_groups_with_pending_reqs?
Hi, Paolo
Thanks for taking time reviewing these patches
I was doing this too complicated, while counting root group into num_groups_with_pending_reqs is much easier. I'll do this in next iteration.
Thanks Yu Kuai
> >> /* >> * Per-class (RT, BE, IDLE) number of bfq_queues containing >> * requests (including the queue in service, even if it is >> diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c >> index 7a462df71f68..188c8f907219 100644 >> --- a/block/bfq-wf2q.c >> +++ b/block/bfq-wf2q.c >> @@ -946,6 +946,29 @@ static void bfq_update_fin_time_enqueue(struct bfq_entity *entity, >> bfq_active_insert(st, entity); >> } >> >> +static void bfq_update_groups_with_pending_reqs(struct bfq_entity *entity) >> +{ >> +#ifdef CONFIG_BFQ_GROUP_IOSCHED >> + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); >> + > > why do you introduce an extra variable bfqq, instead of doing as in > the original version of the code? In addition, you remove the comment > /* bfq_group */ > > Thanks, > Paolo > >> + if (bfqq) { >> + if (!entity->parent && !entity->in_groups_with_pending_reqs) { >> + entity->in_groups_with_pending_reqs = true; >> + bfqq->bfqd->num_queues_with_pending_reqs_in_root++; >> + } >> + } else { >> + if (!entity->in_groups_with_pending_reqs) { >> + struct bfq_group *bfqg = >> + container_of(entity, struct bfq_group, entity); >> + struct bfq_data *bfqd = bfqg->bfqd; >> + >> + entity->in_groups_with_pending_reqs = true; >> + bfqd->num_groups_with_pending_reqs++; >> + } >> + } >> +#endif >> +} >> + >> /** >> * __bfq_activate_entity - handle activation of entity. >> * @entity: the entity being activated. >> @@ -999,19 +1022,7 @@ static void __bfq_activate_entity(struct bfq_entity *entity, >> entity->on_st_or_in_serv = true; >> } >> >> -#ifdef CONFIG_BFQ_GROUP_IOSCHED >> - if (!bfq_entity_to_bfqq(entity)) { /* bfq_group */ >> - struct bfq_group *bfqg = >> - container_of(entity, struct bfq_group, entity); >> - struct bfq_data *bfqd = bfqg->bfqd; >> - >> - if (!entity->in_groups_with_pending_reqs) { >> - entity->in_groups_with_pending_reqs = true; >> - bfqd->num_groups_with_pending_reqs++; >> - } >> - } >> -#endif >> - >> + bfq_update_groups_with_pending_reqs(entity); >> bfq_update_fin_time_enqueue(entity, st, backshifted); >> } >> >> -- >> 2.31.1 >> > > . >
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