diff options
| author |   Jan Kara <jack@suse.cz> | 2021-01-11 17:47:16 +0100 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2021-01-24 18:19:46 -0700 |
| commit | 5ac83c644f5fb924f0b2c09102ab82fc788f8411 (patch) | |
| tree | 44ecf60a95b280219d2872c1dec05a3f6f9a7e72 /block | |
| parent | block, bfq: do not expire a queue when it is the only busy one (diff) | |
| download | linux-dev-5ac83c644f5fb924f0b2c09102ab82fc788f8411.tar.xz linux-dev-5ac83c644f5fb924f0b2c09102ab82fc788f8411.zip | |
Revert "blk-mq, elevator: Count requests per hctx to improve performance"
This reverts commit b445547ec1bbd3e7bf4b1c142550942f70527d95.
Since both mq-deadline and BFQ completely ignore hctx they are passed to
their dispatch function and dispatch whatever request they deem fit
checking whether any request for a particular hctx is queued is just
pointless since we'll very likely get a request from a different hctx
anyway. In the following commit we'll deal with lock contention in these
IO schedulers in presence of multiple HW queues in a different way.
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/bfq-iosched.c | 5 | ||||
| -rw-r--r-- | block/blk-mq.c | 1 | ||||
| -rw-r--r-- | block/mq-deadline.c | 6 |
3 files changed, 0 insertions, 12 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index c045613ce927..b12a416b51d7 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -4677,9 +4677,6 @@ static bool bfq_has_work(struct blk_mq_hw_ctx *hctx) { struct bfq_data *bfqd = hctx->queue->elevator->elevator_data; - if (!atomic_read(&hctx->elevator_queued)) - return false; - /* * Avoiding lock: a race on bfqd->busy_queues should cause at * most a call to dispatch for nothing @@ -5597,7 +5594,6 @@ static void bfq_insert_requests(struct blk_mq_hw_ctx *hctx, rq = list_first_entry(list, struct request, queuelist); list_del_init(&rq->queuelist); bfq_insert_request(hctx, rq, at_head); - atomic_inc(&hctx->elevator_queued); } } @@ -5965,7 +5961,6 @@ static void bfq_finish_requeue_request(struct request *rq) bfq_completed_request(bfqq, bfqd); bfq_finish_requeue_request_body(bfqq); - atomic_dec(&rq->mq_hctx->elevator_queued); spin_unlock_irqrestore(&bfqd->lock, flags); } else { diff --git a/block/blk-mq.c b/block/blk-mq.c index 74b17b396f4c..1af6b8a9da5a 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2653,7 +2653,6 @@ 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/block/mq-deadline.c b/block/mq-deadline.c index 800ac902809b..b57470e154c8 100644 --- a/block/mq-deadline.c +++ b/block/mq-deadline.c @@ -386,8 +386,6 @@ static struct request *dd_dispatch_request(struct blk_mq_hw_ctx *hctx) spin_lock(&dd->lock); rq = __dd_dispatch_request(dd); spin_unlock(&dd->lock); - if (rq) - atomic_dec(&rq->mq_hctx->elevator_queued); return rq; } @@ -535,7 +533,6 @@ static void dd_insert_requests(struct blk_mq_hw_ctx *hctx, rq = list_first_entry(list, struct request, queuelist); list_del_init(&rq->queuelist); dd_insert_request(hctx, rq, at_head); - atomic_inc(&hctx->elevator_queued); } spin_unlock(&dd->lock); } @@ -582,9 +579,6 @@ static bool dd_has_work(struct blk_mq_hw_ctx *hctx) { struct deadline_data *dd = hctx->queue->elevator->elevator_data; - if (!atomic_read(&hctx->elevator_queued)) - return false; - return !list_empty_careful(&dd->dispatch) || !list_empty_careful(&dd->fifo_list[0]) || !list_empty_careful(&dd->fifo_list[1]); |