From: Ming Lei <ming.lei@redhat.com>
To: Hannes Reinecke <hare@suse.de>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>,
John Garry <john.garry@huawei.com>,
axboe@kernel.dk, jejb@linux.ibm.com, martin.petersen@oracle.com,
don.brace@microsemi.com, Sumit Saxena <sumit.saxena@broadcom.com>,
bvanassche@acm.org, hare@suse.com, hch@lst.de,
Shivasharan Srikanteshwara
<shivasharan.srikanteshwara@broadcom.com>,
linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
esc.storagedev@microsemi.com, chenxiang66@hisilicon.com,
"PDL,MEGARAIDLINUX" <megaraidlinux.pdl@broadcom.com>
Subject: Re: [PATCH RFC v7 00/12] blk-mq/scsi: Provide hostwide shared tags for SCSI HBAs
Date: Tue, 23 Jun 2020 08:55:18 +0800 [thread overview]
Message-ID: <20200623005518.GA843366@T590> (raw)
In-Reply-To: <67d626a6-1b7c-fbc8-24b6-8d6b6df8a7b8@suse.de>
On Mon, Jun 22, 2020 at 08:24:39AM +0200, Hannes Reinecke wrote:
> On 6/17/20 1:26 PM, Kashyap Desai wrote:
> > >
> > > ->queued is increased only and not decreased just for debug purpose so
> > > ->far, so
> > > it can't be relied for this purpose.
> >
> > Thanks. I overlooked that that it is only incremental counter.
> >
> > >
> > > One approach is to add one similar counter, and maintain it by
> > scheduler's
> > > insert/dispatch callback.
> >
> > I tried below and I see performance is on expected range.
> >
> > diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
> > index fdcc2c1..ea201d0 100644
> > --- a/block/blk-mq-sched.c
> > +++ b/block/blk-mq-sched.c
> > @@ -485,6 +485,7 @@ void blk_mq_sched_insert_request(struct request *rq,
> > bool at_head,
> >
> > list_add(&rq->queuelist, &list);
> > e->type->ops.insert_requests(hctx, &list, at_head);
> > + atomic_inc(&hctx->elevator_queued);
> > } else {
> > spin_lock(&ctx->lock);
> > __blk_mq_insert_request(hctx, rq, at_head);
> > @@ -511,8 +512,10 @@ void blk_mq_sched_insert_requests(struct
> > blk_mq_hw_ctx *hctx,
> > percpu_ref_get(&q->q_usage_counter);
> >
> > e = hctx->queue->elevator;
> > - if (e && e->type->ops.insert_requests)
> > + if (e && e->type->ops.insert_requests) {
> > e->type->ops.insert_requests(hctx, list, false);
> > + atomic_inc(&hctx->elevator_queued);
> > + }
> > else {
> > /*
> > * try to issue requests directly if the hw queue isn't
> > diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
> > index 126021f..946b47a 100644
> > --- a/block/blk-mq-sched.h
> > +++ b/block/blk-mq-sched.h
> > @@ -74,6 +74,13 @@ static inline bool blk_mq_sched_has_work(struct
> > blk_mq_hw_ctx *hctx)
> > {
> > struct elevator_queue *e = hctx->queue->elevator;
> >
> > + /* If current hctx has not queued any request, there is no need to
> > run.
> > + * blk_mq_run_hw_queue() on hctx which has queued IO will handle
> > + * running specific hctx.
> > + */
> > + if (!atomic_read(&hctx->elevator_queued))
> > + return false;
> > +
> > if (e && e->type->ops.has_work)
> > return e->type->ops.has_work(hctx);
> >
> > diff --git a/block/blk-mq.c b/block/blk-mq.c
> > index f73a2f9..48f1824 100644
> > --- a/block/blk-mq.c
> > +++ b/block/blk-mq.c
> > @@ -517,8 +517,10 @@ void blk_mq_free_request(struct request *rq)
> > struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
> >
> > if (rq->rq_flags & RQF_ELVPRIV) {
> > - if (e && e->type->ops.finish_request)
> > + if (e && e->type->ops.finish_request) {
> > e->type->ops.finish_request(rq);
> > + atomic_dec(&hctx->elevator_queued);
> > + }
> > if (rq->elv.icq) {
> > put_io_context(rq->elv.icq->ioc);
> > rq->elv.icq = NULL;
> > @@ -2571,6 +2573,7 @@ blk_mq_alloc_hctx(struct request_queue *q, struct
> > blk_mq_tag_set *set,
> > goto free_hctx;
> >
> > atomic_set(&hctx->nr_active, 0);
> > + atomic_set(&hctx->elevator_queued, 0);
> > if (node == NUMA_NO_NODE)
> > node = set->numa_node;
> > hctx->numa_node = node;
> > diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
> > index 66711c7..ea1ddb1 100644
> > --- a/include/linux/blk-mq.h
> > +++ b/include/linux/blk-mq.h
> > @@ -139,6 +139,10 @@ struct blk_mq_hw_ctx {
> > * shared across request queues.
> > */
> > atomic_t nr_active;
> > + /**
> > + * @elevator_queued: Number of queued requests on hctx.
> > + */
> > + atomic_t elevator_queued;
> >
> > /** @cpuhp_online: List to store request if CPU is going to die */
> > struct hlist_node cpuhp_online;
> >
> >
> >
> Would it make sense to move it into the elevator itself?
That is my initial suggestion, and the counter is just done for bfq &
mq-deadline, then we needn't to pay the cost for others.
Thanks,
Ming
next prev parent reply other threads:[~2020-06-23 0:56 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 17:29 [PATCH RFC v7 00/12] blk-mq/scsi: Provide hostwide shared tags for SCSI HBAs John Garry
2020-06-10 17:29 ` [PATCH RFC v7 01/12] blk-mq: rename BLK_MQ_F_TAG_SHARED as BLK_MQ_F_TAG_QUEUE_SHARED John Garry
2020-06-10 17:29 ` [PATCH RFC v7 02/12] blk-mq: rename blk_mq_update_tag_set_depth() John Garry
2020-06-11 2:57 ` Ming Lei
2020-06-11 8:26 ` John Garry
2020-06-23 11:25 ` John Garry
2020-06-23 14:23 ` Hannes Reinecke
2020-06-24 8:13 ` Kashyap Desai
2020-06-29 16:18 ` John Garry
2020-08-10 16:51 ` Kashyap Desai
2020-08-11 8:01 ` John Garry
2020-08-11 16:34 ` Kashyap Desai
2020-06-10 17:29 ` [PATCH RFC v7 03/12] blk-mq: Use pointers for blk_mq_tags bitmap tags John Garry
2020-06-10 17:29 ` [PATCH RFC v7 04/12] blk-mq: Facilitate a shared sbitmap per tagset John Garry
2020-06-11 3:37 ` Ming Lei
2020-06-11 10:09 ` John Garry
2020-06-10 17:29 ` [PATCH RFC v7 05/12] blk-mq: Record nr_active_requests per queue for when using shared sbitmap John Garry
2020-06-11 4:04 ` Ming Lei
2020-06-11 10:22 ` John Garry
2020-06-10 17:29 ` [PATCH RFC v7 06/12] blk-mq: Record active_queues_shared_sbitmap per tag_set " John Garry
2020-06-11 13:16 ` Hannes Reinecke
2020-06-11 14:22 ` John Garry
2020-06-10 17:29 ` [PATCH RFC v7 07/12] blk-mq: Add support in hctx_tags_bitmap_show() for a " John Garry
2020-06-11 13:19 ` Hannes Reinecke
2020-06-11 14:33 ` John Garry
2020-06-12 6:06 ` Hannes Reinecke
2020-06-29 15:32 ` About sbitmap_bitmap_show() and cleared bits (was Re: [PATCH RFC v7 07/12] blk-mq: Add support in hctx_tags_bitmap_show() for a shared sbitmap) John Garry
2020-06-30 6:33 ` Hannes Reinecke
2020-06-30 7:30 ` John Garry
2020-06-30 11:36 ` John Garry
2020-06-30 14:55 ` Bart Van Assche
2020-07-13 9:41 ` [PATCH RFC v7 07/12] blk-mq: Add support in hctx_tags_bitmap_show() for a shared sbitmap John Garry
2020-07-13 12:20 ` Hannes Reinecke
2020-06-10 17:29 ` [PATCH RFC v7 08/12] scsi: Add template flag 'host_tagset' John Garry
2020-06-10 17:29 ` [PATCH RFC v7 09/12] scsi: hisi_sas: Switch v3 hw to MQ John Garry
2020-06-10 17:29 ` [PATCH RFC v7 10/12] megaraid_sas: switch fusion adapters " John Garry
2020-07-02 10:23 ` Kashyap Desai
2020-07-06 8:23 ` John Garry
2020-07-06 8:45 ` Hannes Reinecke
2020-07-06 9:26 ` John Garry
2020-07-06 9:40 ` Hannes Reinecke
2020-07-06 19:19 ` Kashyap Desai
2020-07-07 7:58 ` John Garry
2020-07-07 14:45 ` Kashyap Desai
2020-07-07 16:17 ` John Garry
2020-07-09 19:01 ` Kashyap Desai
2020-07-10 8:10 ` John Garry
2020-07-13 7:55 ` Kashyap Desai
2020-07-13 8:42 ` John Garry
2020-07-19 19:07 ` Kashyap Desai
2020-07-20 7:23 ` Kashyap Desai
2020-07-20 9:18 ` John Garry
2020-07-21 1:13 ` Ming Lei
2020-07-21 6:53 ` Kashyap Desai
2020-07-22 4:12 ` Ming Lei
2020-07-22 5:30 ` Kashyap Desai
2020-07-22 8:04 ` Ming Lei
2020-07-22 9:32 ` John Garry
2020-07-23 14:07 ` Ming Lei
2020-07-23 17:29 ` John Garry
2020-07-24 2:47 ` Ming Lei
2020-07-28 7:54 ` John Garry
2020-07-28 8:45 ` Ming Lei
2020-07-29 5:25 ` Kashyap Desai
2020-07-29 15:36 ` Ming Lei
2020-07-29 18:31 ` Kashyap Desai
2020-08-04 8:36 ` Ming Lei
2020-08-04 9:27 ` Kashyap Desai
2020-08-05 8:40 ` Ming Lei
2020-08-06 10:25 ` Kashyap Desai
2020-08-06 13:38 ` Ming Lei
2020-08-06 14:37 ` Kashyap Desai
2020-08-06 15:29 ` Ming Lei
2020-08-08 19:05 ` Kashyap Desai
2020-08-09 2:16 ` Ming Lei
2020-08-10 16:38 ` Kashyap Desai
2020-08-11 8:09 ` John Garry
2020-08-04 17:00 ` John Garry
2020-08-05 2:56 ` Ming Lei
2020-07-28 8:01 ` Kashyap Desai
2020-07-08 11:31 ` John Garry
2020-06-10 17:29 ` [PATCH RFC v7 11/12] smartpqi: enable host tagset John Garry
2020-07-14 13:16 ` John Garry
2020-07-14 13:31 ` John Garry
2020-07-14 18:16 ` Don.Brace
2020-07-15 7:28 ` John Garry
2020-07-14 14:02 ` Hannes Reinecke
2020-08-18 8:33 ` John Garry
2020-06-10 17:29 ` [PATCH RFC v7 12/12] hpsa: enable host_tagset and switch to MQ John Garry
2020-07-14 7:37 ` John Garry
2020-07-14 7:41 ` Hannes Reinecke
2020-07-14 7:52 ` John Garry
2020-07-14 8:06 ` Ming Lei
2020-07-14 9:53 ` John Garry
2020-07-14 10:14 ` Ming Lei
2020-07-14 10:43 ` Hannes Reinecke
2020-07-14 10:19 ` Hannes Reinecke
2020-07-14 10:35 ` John Garry
2020-07-14 10:44 ` Ming Lei
2020-07-14 10:52 ` John Garry
2020-07-14 12:04 ` Ming Lei
2020-08-03 20:39 ` Don.Brace
2020-08-04 9:27 ` John Garry
2020-08-04 15:18 ` Don.Brace
2020-08-05 11:21 ` John Garry
2020-08-14 21:04 ` Don.Brace
2020-08-17 8:00 ` John Garry
2020-08-17 18:39 ` Don.Brace
2020-08-18 7:14 ` Hannes Reinecke
2020-07-16 16:14 ` Don.Brace
2020-07-16 19:45 ` Don.Brace
2020-07-17 10:11 ` John Garry
2020-06-11 3:07 ` [PATCH RFC v7 00/12] blk-mq/scsi: Provide hostwide shared tags for SCSI HBAs Ming Lei
2020-06-11 9:35 ` John Garry
2020-06-12 18:47 ` Kashyap Desai
2020-06-15 2:13 ` Ming Lei
2020-06-15 6:57 ` Kashyap Desai
2020-06-16 1:00 ` Ming Lei
2020-06-17 11:26 ` Kashyap Desai
2020-06-22 6:24 ` Hannes Reinecke
2020-06-23 0:55 ` Ming Lei [this message]
2020-06-23 11:50 ` Kashyap Desai
2020-06-23 12:11 ` Kashyap Desai
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