diff options
Diffstat (limited to 'block/bfq-cgroup.c')
-rw-r--r-- | block/bfq-cgroup.c | 115 |
1 files changed, 71 insertions, 44 deletions
diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index c17eb794f0ae..59fd1b10b5f3 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -536,6 +536,7 @@ static void bfq_pd_init(struct blkg_policy_data *pd) */ bfqg->bfqd = bfqd; bfqg->active_entities = 0; + bfqg->online = true; bfqg->rq_pos_tree = RB_ROOT; } @@ -564,28 +565,11 @@ static void bfq_group_set_parent(struct bfq_group *bfqg, entity->sched_data = &parent->sched_data; } -static struct bfq_group *bfq_lookup_bfqg(struct bfq_data *bfqd, - struct blkcg *blkcg) +static void bfq_link_bfqg(struct bfq_data *bfqd, struct bfq_group *bfqg) { - struct blkcg_gq *blkg; - - blkg = blkg_lookup(blkcg, bfqd->queue); - if (likely(blkg)) - return blkg_to_bfqg(blkg); - return NULL; -} - -struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, - struct blkcg *blkcg) -{ - struct bfq_group *bfqg, *parent; + struct bfq_group *parent; struct bfq_entity *entity; - bfqg = bfq_lookup_bfqg(bfqd, blkcg); - - if (unlikely(!bfqg)) - return NULL; - /* * Update chain of bfq_groups as we might be handling a leaf group * which, along with some of its relatives, has not been hooked yet @@ -602,8 +586,28 @@ struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, bfq_group_set_parent(curr_bfqg, parent); } } +} - return bfqg; +struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio) +{ + struct blkcg_gq *blkg = bio->bi_blkg; + struct bfq_group *bfqg; + + while (blkg) { + if (!blkg->online) { + blkg = blkg->parent; + continue; + } + bfqg = blkg_to_bfqg(blkg); + if (bfqg->online) { + bio_associate_blkg_from_css(bio, &blkg->blkcg->css); + return bfqg; + } + blkg = blkg->parent; + } + bio_associate_blkg_from_css(bio, + &bfqg_to_blkg(bfqd->root_group)->blkcg->css); + return bfqd->root_group; } /** @@ -679,25 +683,15 @@ void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, * Move bic to blkcg, assuming that bfqd->lock is held; which makes * sure that the reference to cgroup is valid across the call (see * comments in bfq_bic_update_cgroup on this issue) - * - * NOTE: an alternative approach might have been to store the current - * cgroup in bfqq and getting a reference to it, reducing the lookup - * time here, at the price of slightly more complex code. */ -static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd, - struct bfq_io_cq *bic, - struct blkcg *blkcg) +static void *__bfq_bic_change_cgroup(struct bfq_data *bfqd, + struct bfq_io_cq *bic, + struct bfq_group *bfqg) { struct bfq_queue *async_bfqq = bic_to_bfqq(bic, 0); struct bfq_queue *sync_bfqq = bic_to_bfqq(bic, 1); - struct bfq_group *bfqg; struct bfq_entity *entity; - bfqg = bfq_find_set_group(bfqd, blkcg); - - if (unlikely(!bfqg)) - bfqg = bfqd->root_group; - if (async_bfqq) { entity = &async_bfqq->entity; @@ -708,9 +702,39 @@ static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd, } if (sync_bfqq) { - entity = &sync_bfqq->entity; - if (entity->sched_data != &bfqg->sched_data) - bfq_bfqq_move(bfqd, sync_bfqq, bfqg); + if (!sync_bfqq->new_bfqq && !bfq_bfqq_coop(sync_bfqq)) { + /* We are the only user of this bfqq, just move it */ + if (sync_bfqq->entity.sched_data != &bfqg->sched_data) + bfq_bfqq_move(bfqd, sync_bfqq, bfqg); + } else { + struct bfq_queue *bfqq; + + /* + * The queue was merged to a different queue. Check + * that the merge chain still belongs to the same + * cgroup. + */ + for (bfqq = sync_bfqq; bfqq; bfqq = bfqq->new_bfqq) + if (bfqq->entity.sched_data != + &bfqg->sched_data) + break; + if (bfqq) { + /* + * Some queue changed cgroup so the merge is + * not valid anymore. We cannot easily just + * cancel the merge (by clearing new_bfqq) as + * there may be other processes using this + * queue and holding refs to all queues below + * sync_bfqq->new_bfqq. Similarly if the merge + * already happened, we need to detach from + * bfqq now so that we cannot merge bio to a + * request from the old cgroup. + */ + bfq_put_cooperator(sync_bfqq); + bfq_release_process_ref(bfqd, sync_bfqq); + bic_set_bfqq(bic, NULL, 1); + } + } } return bfqg; @@ -719,20 +743,24 @@ static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd, void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) { struct bfq_data *bfqd = bic_to_bfqd(bic); - struct bfq_group *bfqg = NULL; + struct bfq_group *bfqg = bfq_bio_bfqg(bfqd, bio); uint64_t serial_nr; - rcu_read_lock(); - serial_nr = __bio_blkcg(bio)->css.serial_nr; + serial_nr = bfqg_to_blkg(bfqg)->blkcg->css.serial_nr; /* * Check whether blkcg has changed. The condition may trigger * spuriously on a newly created cic but there's no harm. */ if (unlikely(!bfqd) || likely(bic->blkcg_serial_nr == serial_nr)) - goto out; + return; - bfqg = __bfq_bic_change_cgroup(bfqd, bic, __bio_blkcg(bio)); + /* + * New cgroup for this process. Make sure it is linked to bfq internal + * cgroup hierarchy. + */ + bfq_link_bfqg(bfqd, bfqg); + __bfq_bic_change_cgroup(bfqd, bic, bfqg); /* * Update blkg_path for bfq_log_* functions. We cache this * path, and update it here, for the following @@ -785,8 +813,6 @@ void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) */ blkg_path(bfqg_to_blkg(bfqg), bfqg->blkg_path, sizeof(bfqg->blkg_path)); bic->blkcg_serial_nr = serial_nr; -out: - rcu_read_unlock(); } /** @@ -914,6 +940,7 @@ 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); /* @@ -1402,7 +1429,7 @@ void bfq_end_wr_async(struct bfq_data *bfqd) bfq_end_wr_async_queues(bfqd, bfqd->root_group); } -struct bfq_group *bfq_find_set_group(struct bfq_data *bfqd, struct blkcg *blkcg) +struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio) { return bfqd->root_group; } |