| Message ID | 20171009112424.30524-2-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Mon, Oct 09, 2017 at 07:24:20PM +0800, Ming Lei wrote: > When hw queue is busy, we shouldn't take requests from > scheduler queue any more, otherwise it is difficult to do > IO merge. > > This patch fixes the awful IO performance on some > SCSI devices(lpfc, qla2xxx, ...) when mq-deadline/kyber > is used by not taking requests if hw queue is busy. > > Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> > Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Omar Sandoval <osandov@fb.com> > Signed-off-by: Ming Lei <ming.lei@redhat.com> > --- > block/blk-mq-sched.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c > index 4ab69435708c..eca011fdfa0e 100644 > --- a/block/blk-mq-sched.c > +++ b/block/blk-mq-sched.c > @@ -94,7 +94,7 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) > struct request_queue *q = hctx->queue; > struct elevator_queue *e = q->elevator; > const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request; > - bool did_work = false; > + bool do_sched_dispatch = true; > LIST_HEAD(rq_list); > > /* RCU or SRCU read lock is needed before checking quiesced flag */ > @@ -125,18 +125,18 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) > */ > if (!list_empty(&rq_list)) { > blk_mq_sched_mark_restart_hctx(hctx); > - did_work = blk_mq_dispatch_rq_list(q, &rq_list); > + do_sched_dispatch = blk_mq_dispatch_rq_list(q, &rq_list); > } else if (!has_sched_dispatch) { > blk_mq_flush_busy_ctxs(hctx, &rq_list); > blk_mq_dispatch_rq_list(q, &rq_list); > } > > /* > - * We want to dispatch from the scheduler if we had no work left > - * on the dispatch list, OR if we did have work but weren't able > - * to make progress. > + * We want to dispatch from the scheduler if there was nothing > + * on the dispatch list or we were able to dispatch from the > + * dispatch list. > */ > - if (!did_work && has_sched_dispatch) { > + if (do_sched_dispatch && has_sched_dispatch) { > do { > struct request *rq; > > -- > 2.9.5 >
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 4ab69435708c..eca011fdfa0e 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -94,7 +94,7 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) struct request_queue *q = hctx->queue; struct elevator_queue *e = q->elevator; const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request; - bool did_work = false; + bool do_sched_dispatch = true; LIST_HEAD(rq_list); /* RCU or SRCU read lock is needed before checking quiesced flag */ @@ -125,18 +125,18 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) */ if (!list_empty(&rq_list)) { blk_mq_sched_mark_restart_hctx(hctx); - did_work = blk_mq_dispatch_rq_list(q, &rq_list); + do_sched_dispatch = blk_mq_dispatch_rq_list(q, &rq_list); } else if (!has_sched_dispatch) { blk_mq_flush_busy_ctxs(hctx, &rq_list); blk_mq_dispatch_rq_list(q, &rq_list); } /* - * We want to dispatch from the scheduler if we had no work left - * on the dispatch list, OR if we did have work but weren't able - * to make progress. + * We want to dispatch from the scheduler if there was nothing + * on the dispatch list or we were able to dispatch from the + * dispatch list. */ - if (!did_work && has_sched_dispatch) { + if (do_sched_dispatch && has_sched_dispatch) { do { struct request *rq;