diff options
Diffstat (limited to 'block/bfq-iosched.c')
| -rw-r--r-- | block/bfq-iosched.c | 68 |
1 files changed, 47 insertions, 21 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 586fcfe227ea..b33be928d164 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -1924,12 +1924,13 @@ static void bfq_add_request(struct request *rq) * confirmed no later than during the next * I/O-plugging interval for bfqq. */ - if (!bfq_bfqq_has_short_ttime(bfqq) && + if (bfqd->last_completed_rq_bfqq && + !bfq_bfqq_has_short_ttime(bfqq) && ktime_get_ns() - bfqd->last_completion < 200 * NSEC_PER_USEC) { if (bfqd->last_completed_rq_bfqq != bfqq && - bfqd->last_completed_rq_bfqq != - bfqq->waker_bfqq) { + bfqd->last_completed_rq_bfqq != + bfqq->waker_bfqq) { /* * First synchronization detected with * a candidate waker queue, or with a @@ -2250,9 +2251,14 @@ static void bfq_request_merged(struct request_queue *q, struct request *req, blk_rq_pos(container_of(rb_prev(&req->rb_node), struct request, rb_node))) { struct bfq_queue *bfqq = bfq_init_rq(req); - struct bfq_data *bfqd = bfqq->bfqd; + struct bfq_data *bfqd; struct request *prev, *next_rq; + if (!bfqq) + return; + + bfqd = bfqq->bfqd; + /* Reposition request in its sort_list */ elv_rb_del(&bfqq->sort_list, req); elv_rb_add(&bfqq->sort_list, req); @@ -2299,6 +2305,9 @@ static void bfq_requests_merged(struct request_queue *q, struct request *rq, struct bfq_queue *bfqq = bfq_init_rq(rq), *next_bfqq = bfq_init_rq(next); + if (!bfqq) + return; + /* * If next and rq belong to the same bfq_queue and next is older * than rq, then reposition rq in the fifo (by substituting next @@ -4764,6 +4773,8 @@ static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) */ void bfq_put_queue(struct bfq_queue *bfqq) { + struct bfq_queue *item; + struct hlist_node *n; #ifdef CONFIG_BFQ_GROUP_IOSCHED struct bfq_group *bfqg = bfqq_group(bfqq); #endif @@ -4808,6 +4819,36 @@ void bfq_put_queue(struct bfq_queue *bfqq) bfqq->bfqd->burst_size--; } + /* + * bfqq does not exist any longer, so it cannot be woken by + * any other queue, and cannot wake any other queue. Then bfqq + * must be removed from the woken list of its possible waker + * queue, and all queues in the woken list of bfqq must stop + * having a waker queue. Strictly speaking, these updates + * should be performed when bfqq remains with no I/O source + * attached to it, which happens before bfqq gets freed. In + * particular, this happens when the last process associated + * with bfqq exits or gets associated with a different + * queue. However, both events lead to bfqq being freed soon, + * and dangling references would come out only after bfqq gets + * freed. So these updates are done here, as a simple and safe + * way to handle all cases. + */ + /* remove bfqq from woken list */ + if (!hlist_unhashed(&bfqq->woken_list_node)) + hlist_del_init(&bfqq->woken_list_node); + + /* reset waker for all queues in woken list */ + hlist_for_each_entry_safe(item, n, &bfqq->woken_list, + woken_list_node) { + item->waker_bfqq = NULL; + bfq_clear_bfqq_has_waker(item); + hlist_del_init(&item->woken_list_node); + } + + if (bfqq->bfqd && bfqq->bfqd->last_completed_rq_bfqq == bfqq) + bfqq->bfqd->last_completed_rq_bfqq = NULL; + kmem_cache_free(bfq_pool, bfqq); #ifdef CONFIG_BFQ_GROUP_IOSCHED bfqg_and_blkg_put(bfqg); @@ -4835,9 +4876,6 @@ static void bfq_put_cooperator(struct bfq_queue *bfqq) static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) { - struct bfq_queue *item; - struct hlist_node *n; - if (bfqq == bfqd->in_service_queue) { __bfq_bfqq_expire(bfqd, bfqq, BFQQE_BUDGET_TIMEOUT); bfq_schedule_dispatch(bfqd); @@ -4847,18 +4885,6 @@ static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) bfq_put_cooperator(bfqq); - /* remove bfqq from woken list */ - if (!hlist_unhashed(&bfqq->woken_list_node)) - hlist_del_init(&bfqq->woken_list_node); - - /* reset waker for all queues in woken list */ - hlist_for_each_entry_safe(item, n, &bfqq->woken_list, - woken_list_node) { - item->waker_bfqq = NULL; - bfq_clear_bfqq_has_waker(item); - hlist_del_init(&item->woken_list_node); - } - bfq_put_queue(bfqq); /* release process reference */ } @@ -5436,12 +5462,12 @@ static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, spin_lock_irq(&bfqd->lock); bfqq = bfq_init_rq(rq); - if (at_head || blk_rq_is_passthrough(rq)) { + if (!bfqq || at_head || blk_rq_is_passthrough(rq)) { if (at_head) list_add(&rq->queuelist, &bfqd->dispatch); else list_add_tail(&rq->queuelist, &bfqd->dispatch); - } else { /* bfqq is assumed to be non null here */ + } else { idle_timer_disabled = __bfq_insert_request(bfqd, rq); /* * Update bfqq, because, if a queue merge has occurred |