diff options
Diffstat (limited to 'block/cfq-iosched.c')
| -rw-r--r-- | block/cfq-iosched.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 1f96ad6254f..16ace89613b 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -130,6 +130,8 @@ struct cfq_queue { unsigned long slice_end; long slice_resid; + /* pending priority requests */ + int prio_pending; /* number of requests that are on the dispatch list or inside driver */ int dispatched; @@ -682,6 +684,9 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, if (rq_is_sync(rq1) != rq_is_sync(rq2)) return rq_is_sync(rq1) ? rq1 : rq2; + if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO) + return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2; + s1 = blk_rq_pos(rq1); s2 = blk_rq_pos(rq2); @@ -1209,6 +1214,9 @@ static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg) hlist_del_init(&cfqg->cfqd_node); + BUG_ON(cfqd->nr_blkcg_linked_grps <= 0); + cfqd->nr_blkcg_linked_grps--; + /* * Put the reference taken at the time of creation so that when all * queues are gone, group can be destroyed. @@ -1604,6 +1612,10 @@ static void cfq_remove_request(struct request *rq) cfqq->cfqd->rq_queued--; cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, rq_data_dir(rq), rq_is_sync(rq)); + if (rq->cmd_flags & REQ_PRIO) { + WARN_ON(!cfqq->prio_pending); + cfqq->prio_pending--; + } } static int cfq_merge(struct request_queue *q, struct request **req, @@ -3357,6 +3369,13 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, return true; /* + * So both queues are sync. Let the new request get disk time if + * it's a metadata request and the current queue is doing regular IO. + */ + if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending) + return true; + + /* * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. */ if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) @@ -3420,6 +3439,8 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, struct cfq_io_context *cic = RQ_CIC(rq); cfqd->rq_queued++; + if (rq->cmd_flags & REQ_PRIO) + cfqq->prio_pending++; cfq_update_io_thinktime(cfqd, cfqq, cic); cfq_update_io_seektime(cfqd, cfqq, rq); |