diff options
Diffstat (limited to 'block/cfq-iosched.c')
| -rw-r--r-- | block/cfq-iosched.c | 52 |
1 files changed, 41 insertions, 11 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 11ce6aaf1bd02..8e9d84825e1c5 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -133,6 +133,7 @@ struct cfq_data { mempool_t *crq_pool; int rq_in_driver; + int hw_tag; /* * schedule slice state info @@ -500,10 +501,13 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) /* * if queue was preempted, just add to front to be fair. busy_rr - * isn't sorted. + * isn't sorted, but insert at the back for fairness. */ if (preempted || list == &cfqd->busy_rr) { - list_add(&cfqq->cfq_list, list); + if (preempted) + list = list->prev; + + list_add_tail(&cfqq->cfq_list, list); return; } @@ -664,6 +668,15 @@ static void cfq_activate_request(request_queue_t *q, struct request *rq) struct cfq_data *cfqd = q->elevator->elevator_data; cfqd->rq_in_driver++; + + /* + * If the depth is larger 1, it really could be queueing. But lets + * make the mark a little higher - idling could still be good for + * low queueing, and a low queueing number could also just indicate + * a SCSI mid layer like behaviour where limit+1 is often seen. + */ + if (!cfqd->hw_tag && cfqd->rq_in_driver > 4) + cfqd->hw_tag = 1; } static void cfq_deactivate_request(request_queue_t *q, struct request *rq) @@ -879,6 +892,13 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) cfqq = list_entry_cfqq(cfqd->cur_rr.next); /* + * If no new queues are available, check if the busy list has some + * before falling back to idle io. + */ + if (!cfqq && !list_empty(&cfqd->busy_rr)) + cfqq = list_entry_cfqq(cfqd->busy_rr.next); + + /* * if we have idle queues and no rt or be queues had pending * requests, either allow immediate service if the grace period * has passed or arm the idle grace timer @@ -1458,7 +1478,8 @@ retry: * set ->slice_left to allow preemption for a new process */ cfqq->slice_left = 2 * cfqd->cfq_slice_idle; - cfq_mark_cfqq_idle_window(cfqq); + if (!cfqd->hw_tag) + cfq_mark_cfqq_idle_window(cfqq); cfq_mark_cfqq_prio_changed(cfqq); cfq_init_prio_data(cfqq); } @@ -1649,7 +1670,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, { int enable_idle = cfq_cfqq_idle_window(cfqq); - if (!cic->ioc->task || !cfqd->cfq_slice_idle) + if (!cic->ioc->task || !cfqd->cfq_slice_idle || cfqd->hw_tag) enable_idle = 0; else if (sample_valid(cic->ttime_samples)) { if (cic->ttime_mean > cfqd->cfq_slice_idle) @@ -1740,14 +1761,24 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); + cic = crq->io_context; + /* * we never wait for an async request and we don't allow preemption * of an async request. so just return early */ - if (!cfq_crq_is_sync(crq)) + if (!cfq_crq_is_sync(crq)) { + /* + * sync process issued an async request, if it's waiting + * then expire it and kick rq handling. + */ + if (cic == cfqd->active_cic && + del_timer(&cfqd->idle_slice_timer)) { + cfq_slice_expired(cfqd, 0); + cfq_start_queueing(cfqd, cfqq); + } return; - - cic = crq->io_context; + } cfq_update_io_thinktime(cfqd, cic); cfq_update_io_seektime(cfqd, cic, crq); @@ -2165,10 +2196,9 @@ static void cfq_idle_class_timer(unsigned long data) * race with a non-idle queue, reset timer */ end = cfqd->last_end_request + CFQ_IDLE_GRACE; - if (!time_after_eq(jiffies, end)) { - cfqd->idle_class_timer.expires = end; - add_timer(&cfqd->idle_class_timer); - } else + if (!time_after_eq(jiffies, end)) + mod_timer(&cfqd->idle_class_timer, end); + else cfq_schedule_dispatch(cfqd); spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); |