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@xxxxxxx>
---
block/bfq-iosched.c | 5 -----
block/blk-mq.c | 1 -
block/mq-deadline.c | 6 ------
include/linux/blk-mq.h | 4 ----
4 files changed, 16 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 9e81d1052091..a99dfaa75a8c 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -4640,9 +4640,6 @@ 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
@@ -5557,7 +5554,6 @@ 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);
}
}
@@ -5925,7 +5921,6 @@ 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 b09ce00cc6af..57d0461f2be5 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2670,7 +2670,6 @@ 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]);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 47b021952ac7..8296811a031e 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -140,10 +140,6 @@ 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;
--
2.16.4
