diff options
Diffstat (limited to 'block/cfq-iosched.c')
| -rw-r--r-- | block/cfq-iosched.c | 70 |
1 files changed, 49 insertions, 21 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index fab2be0fa21..7f5646ac9f5 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -393,7 +393,7 @@ static int cfq_queue_empty(struct request_queue *q) { struct cfq_data *cfqd = q->elevator->elevator_data; - return !cfqd->busy_queues; + return !cfqd->rq_queued; } /* @@ -842,7 +842,6 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) static void cfq_del_rq_rb(struct request *rq) { struct cfq_queue *cfqq = RQ_CFQQ(rq); - struct cfq_data *cfqd = cfqq->cfqd; const int sync = rq_is_sync(rq); BUG_ON(!cfqq->queued[sync]); @@ -850,8 +849,17 @@ static void cfq_del_rq_rb(struct request *rq) elv_rb_del(&cfqq->sort_list, rq); - if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) - cfq_del_cfqq_rr(cfqd, cfqq); + if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) { + /* + * Queue will be deleted from service tree when we actually + * expire it later. Right now just remove it from prio tree + * as it is empty. + */ + if (cfqq->p_root) { + rb_erase(&cfqq->p_node, cfqq->p_root); + cfqq->p_root = NULL; + } + } } static void cfq_add_rq_rb(struct request *rq) @@ -1065,6 +1073,9 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); } + if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) + cfq_del_cfqq_rr(cfqd, cfqq); + cfq_resort_rr_list(cfqd, cfqq); if (cfqq == cfqd->active_queue) @@ -1094,11 +1105,30 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) service_tree_for(cfqd->serving_group, cfqd->serving_prio, cfqd->serving_type, cfqd); + if (!cfqd->rq_queued) + return NULL; + if (RB_EMPTY_ROOT(&service_tree->rb)) return NULL; return cfq_rb_first(service_tree); } +static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd) +{ + struct cfq_group *cfqg = &cfqd->root_group; + struct cfq_queue *cfqq; + int i, j; + struct cfq_rb_root *st; + + if (!cfqd->rq_queued) + return NULL; + + for_each_cfqg_st(cfqg, i, j, st) + if ((cfqq = cfq_rb_first(st)) != NULL) + return cfqq; + return NULL; +} + /* * Get and set a new active queue for service. */ @@ -1231,6 +1261,9 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) enum wl_prio_t prio = cfqq_prio(cfqq); struct cfq_rb_root *service_tree = cfqq->service_tree; + BUG_ON(!service_tree); + BUG_ON(!service_tree->count); + /* We never do for idle class queues. */ if (prio == IDLE_WORKLOAD) return false; @@ -1243,14 +1276,7 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) * Otherwise, we do only if they are the last ones * in their service tree. */ - if (!service_tree) - service_tree = service_tree_for(cfqq->cfqg, prio, - cfqq_type(cfqq), cfqd); - - if (service_tree->count == 0) - return true; - - return (service_tree->count == 1 && cfq_rb_first(service_tree) == cfqq); + return service_tree->count == 1; } static void cfq_arm_slice_timer(struct cfq_data *cfqd) @@ -1527,6 +1553,8 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) if (!cfqq) goto new_queue; + if (!cfqd->rq_queued) + return NULL; /* * The active queue has run out of time, expire it and select new. */ @@ -1589,6 +1617,9 @@ static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) } BUG_ON(!list_empty(&cfqq->fifo)); + + /* By default cfqq is not expired if it is empty. Do it explicitly */ + __cfq_slice_expired(cfqq->cfqd, cfqq, 0); return dispatched; } @@ -1600,14 +1631,9 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd) { struct cfq_queue *cfqq; int dispatched = 0; - int i, j; - struct cfq_group *cfqg = &cfqd->root_group; - struct cfq_rb_root *st; - for_each_cfqg_st(cfqg, i, j, st) { - while ((cfqq = cfq_rb_first(st)) != NULL) - dispatched += __cfq_forced_dispatch_cfqq(cfqq); - } + while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) + dispatched += __cfq_forced_dispatch_cfqq(cfqq); cfq_slice_expired(cfqd, 0); BUG_ON(cfqd->busy_queues); @@ -1776,13 +1802,13 @@ static void cfq_put_queue(struct cfq_queue *cfqq) cfq_log_cfqq(cfqd, cfqq, "put_queue"); BUG_ON(rb_first(&cfqq->sort_list)); BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); - BUG_ON(cfq_cfqq_on_rr(cfqq)); if (unlikely(cfqd->active_queue == cfqq)) { __cfq_slice_expired(cfqd, cfqq, 0); cfq_schedule_dispatch(cfqd); } + BUG_ON(cfq_cfqq_on_rr(cfqq)); kmem_cache_free(cfq_pool, cfqq); } @@ -2444,9 +2470,11 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, if (cfq_class_idle(cfqq)) return true; + /* Allow preemption only if we are idling on sync-noidle tree */ if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD && cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD && - new_cfqq->service_tree->count == 1) + new_cfqq->service_tree->count == 2 && + RB_EMPTY_ROOT(&cfqq->sort_list)) return true; /* |