diff options
Diffstat (limited to 'block/bfq-iosched.c')
| -rw-r--r-- | block/bfq-iosched.c | 44 |
1 files changed, 1 insertions, 43 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 69144003a694..85554b800970 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -6132,48 +6132,7 @@ static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, spin_lock_irq(&bfqd->lock); bfqq = bfq_init_rq(rq); - - /* - * Reqs with at_head or passthrough flags set are to be put - * directly into dispatch list. Additional case for putting rq - * directly into the dispatch queue: the only active - * bfq_queues are bfqq and either its waker bfq_queue or one - * of its woken bfq_queues. The rationale behind this - * additional condition is as follows: - * - consider a bfq_queue, say Q1, detected as a waker of - * another bfq_queue, say Q2 - * - by definition of a waker, Q1 blocks the I/O of Q2, i.e., - * some I/O of Q1 needs to be completed for new I/O of Q2 - * to arrive. A notable example of waker is journald - * - so, Q1 and Q2 are in any respect the queues of two - * cooperating processes (or of two cooperating sets of - * processes): the goal of Q1's I/O is doing what needs to - * be done so that new Q2's I/O can finally be - * issued. Therefore, if the service of Q1's I/O is delayed, - * then Q2's I/O is delayed too. Conversely, if Q2's I/O is - * delayed, the goal of Q1's I/O is hindered. - * - as a consequence, if some I/O of Q1/Q2 arrives while - * Q2/Q1 is the only queue in service, there is absolutely - * no point in delaying the service of such an I/O. The - * only possible result is a throughput loss - * - so, when the above condition holds, the best option is to - * have the new I/O dispatched as soon as possible - * - the most effective and efficient way to attain the above - * goal is to put the new I/O directly in the dispatch - * list - * - as an additional restriction, Q1 and Q2 must be the only - * busy queues for this commit to put the I/O of Q2/Q1 in - * the dispatch list. This is necessary, because, if also - * other queues are waiting for service, then putting new - * I/O directly in the dispatch list may evidently cause a - * violation of service guarantees for the other queues - */ - if (!bfqq || - (bfqq != bfqd->in_service_queue && - bfqd->in_service_queue != NULL && - bfq_tot_busy_queues(bfqd) == 1 + bfq_bfqq_busy(bfqq) && - (bfqq->waker_bfqq == bfqd->in_service_queue || - bfqd->in_service_queue->waker_bfqq == bfqq)) || at_head) { + if (!bfqq || at_head) { if (at_head) list_add(&rq->queuelist, &bfqd->dispatch); else @@ -6200,7 +6159,6 @@ static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, * merge). */ cmd_flags = rq->cmd_flags; - spin_unlock_irq(&bfqd->lock); bfq_update_insert_stats(q, bfqq, idle_timer_disabled, |