diff options
Diffstat (limited to 'block/bfq-iosched.c')
-rw-r--r-- | block/bfq-iosched.c | 56 |
1 files changed, 41 insertions, 15 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index b528710364e9..a4d558acc48b 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -613,6 +613,10 @@ bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq) bfqq->pos_root = NULL; } + /* oom_bfqq does not participate in queue merging */ + if (bfqq == &bfqd->oom_bfqq) + return; + /* * bfqq cannot be merged any longer (see comments in * bfq_setup_cooperator): no point in adding bfqq into the @@ -2532,6 +2536,26 @@ static void bfq_bfqq_save_state(struct bfq_queue *bfqq) } } +void bfq_release_process_ref(struct bfq_data *bfqd, struct bfq_queue *bfqq) +{ + /* + * To prevent bfqq's service guarantees from being violated, + * bfqq may be left busy, i.e., queued for service, even if + * empty (see comments in __bfq_bfqq_expire() for + * details). But, if no process will send requests to bfqq any + * longer, then there is no point in keeping bfqq queued for + * service. In addition, keeping bfqq queued for service, but + * with no process ref any longer, may have caused bfqq to be + * freed when dequeued from service. But this is assumed to + * never happen. + */ + if (bfq_bfqq_busy(bfqq) && RB_EMPTY_ROOT(&bfqq->sort_list) && + bfqq != bfqd->in_service_queue) + bfq_del_bfqq_busy(bfqd, bfqq, false); + + bfq_put_queue(bfqq); +} + static void bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) @@ -2602,8 +2626,7 @@ bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, */ new_bfqq->pid = -1; bfqq->bic = NULL; - /* release process reference to bfqq */ - bfq_put_queue(bfqq); + bfq_release_process_ref(bfqd, bfqq); } static bool bfq_allow_bio_merge(struct request_queue *q, struct request *rq, @@ -4497,9 +4520,7 @@ static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) */ void bfq_put_queue(struct bfq_queue *bfqq) { -#ifdef CONFIG_BFQ_GROUP_IOSCHED struct bfq_group *bfqg = bfqq_group(bfqq); -#endif if (bfqq->bfqd) bfq_log_bfqq(bfqq->bfqd, bfqq, "put_queue: %p %d", @@ -4542,9 +4563,7 @@ void bfq_put_queue(struct bfq_queue *bfqq) } kmem_cache_free(bfq_pool, bfqq); -#ifdef CONFIG_BFQ_GROUP_IOSCHED bfqg_and_blkg_put(bfqg); -#endif } static void bfq_put_cooperator(struct bfq_queue *bfqq) @@ -4577,7 +4596,7 @@ static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) bfq_put_cooperator(bfqq); - bfq_put_queue(bfqq); /* release process reference */ + bfq_release_process_ref(bfqd, bfqq); } static void bfq_exit_icq_bfqq(struct bfq_io_cq *bic, bool is_sync) @@ -4679,8 +4698,7 @@ static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio) bfqq = bic_to_bfqq(bic, false); if (bfqq) { - /* release process reference on this queue */ - bfq_put_queue(bfqq); + bfq_release_process_ref(bfqd, bfqq); bfqq = bfq_get_queue(bfqd, bio, BLK_RW_ASYNC, bic); bic_set_bfqq(bic, bfqq, false); } @@ -5541,7 +5559,7 @@ bfq_split_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq) bfq_put_cooperator(bfqq); - bfq_put_queue(bfqq); + bfq_release_process_ref(bfqq->bfqd, bfqq); return NULL; } @@ -5756,20 +5774,28 @@ static struct bfq_queue *bfq_init_rq(struct request *rq) return bfqq; } -static void bfq_idle_slice_timer_body(struct bfq_queue *bfqq) +static void +bfq_idle_slice_timer_body(struct bfq_data *bfqd, struct bfq_queue *bfqq) { - struct bfq_data *bfqd = bfqq->bfqd; enum bfqq_expiration reason; unsigned long flags; spin_lock_irqsave(&bfqd->lock, flags); - bfq_clear_bfqq_wait_request(bfqq); + /* + * Considering that bfqq may be in race, we should firstly check + * whether bfqq is in service before doing something on it. If + * the bfqq in race is not in service, it has already been expired + * through __bfq_bfqq_expire func and its wait_request flags has + * been cleared in __bfq_bfqd_reset_in_service func. + */ if (bfqq != bfqd->in_service_queue) { spin_unlock_irqrestore(&bfqd->lock, flags); return; } + bfq_clear_bfqq_wait_request(bfqq); + if (bfq_bfqq_budget_timeout(bfqq)) /* * Also here the queue can be safely expired @@ -5814,7 +5840,7 @@ static enum hrtimer_restart bfq_idle_slice_timer(struct hrtimer *timer) * early. */ if (bfqq) - bfq_idle_slice_timer_body(bfqq); + bfq_idle_slice_timer_body(bfqd, bfqq); return HRTIMER_NORESTART; } @@ -5929,10 +5955,10 @@ static void bfq_exit_queue(struct elevator_queue *e) hrtimer_cancel(&bfqd->idle_slice_timer); -#ifdef CONFIG_BFQ_GROUP_IOSCHED /* release oom-queue reference to root group */ bfqg_and_blkg_put(bfqd->root_group); +#ifdef CONFIG_BFQ_GROUP_IOSCHED blkcg_deactivate_policy(bfqd->queue, &blkcg_policy_bfq); #else spin_lock_irq(&bfqd->lock); |