Commit bccf5e26 authored by John Garry's avatar John Garry Committed by Jens Axboe
Browse files

blk-mq: Record nr_active_requests per queue for when using shared sbitmap 



The per-hctx nr_active value can no longer be used to fairly assign a share
of tag depth per request queue for when using a shared sbitmap, as it does
not consider that the tags are shared tags over all hctx's.

For this case, record the nr_active_requests per request_queue, and make
the judgement based on that value.

Co-developed-with: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: default avatarJohn Garry <john.garry@huawei.com>
Tested-by: Don Brace<don.brace@microsemi.com> #SCSI resv cmds patches used
Tested-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a0235d23

block/blk-core.c

+2 −0
Original line number Diff line number Diff line
@@ -543,6 +543,8 @@ struct request_queue *blk_alloc_queue(int node_id) 
	q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;

	q->node = node_id;



	atomic_set(&q->nr_active_requests_shared_sbitmap, 0);



	timer_setup(&q->backing_dev_info->laptop_mode_wb_timer,

		    laptop_mode_timer_fn, 0);

	timer_setup(&q->timeout, blk_rq_timed_out_timer, 0);

block/blk-mq.c

+2 −2
Original line number Diff line number Diff line
@@ -519,7 +519,7 @@ void blk_mq_free_request(struct request *rq) 


	ctx->rq_completed[rq_is_sync(rq)]++;

	if (rq->rq_flags & RQF_MQ_INFLIGHT)

		atomic_dec(&hctx->nr_active);

		__blk_mq_dec_active_requests(hctx);



	if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))

		laptop_io_completion(q->backing_dev_info);
@@ -1127,7 +1127,7 @@ static bool blk_mq_get_driver_tag(struct request *rq) 
	if ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&

			!(rq->rq_flags & RQF_MQ_INFLIGHT)) {

		rq->rq_flags |= RQF_MQ_INFLIGHT;

		atomic_inc(&hctx->nr_active);

		__blk_mq_inc_active_requests(hctx);

	}

	hctx->tags->rqs[rq->tag] = rq;

	return true;

block/blk-mq.h

+24 −2
Original line number Diff line number Diff line
@@ -199,6 +199,28 @@ static inline bool blk_mq_get_dispatch_budget(struct request_queue *q) 
	return true;

}



static inline void __blk_mq_inc_active_requests(struct blk_mq_hw_ctx *hctx)

{

	if (blk_mq_is_sbitmap_shared(hctx->flags))

		atomic_inc(&hctx->queue->nr_active_requests_shared_sbitmap);

	else

		atomic_inc(&hctx->nr_active);

}



static inline void __blk_mq_dec_active_requests(struct blk_mq_hw_ctx *hctx)

{

	if (blk_mq_is_sbitmap_shared(hctx->flags))

		atomic_dec(&hctx->queue->nr_active_requests_shared_sbitmap);

	else

		atomic_dec(&hctx->nr_active);

}



static inline int __blk_mq_active_requests(struct blk_mq_hw_ctx *hctx)

{

	if (blk_mq_is_sbitmap_shared(hctx->flags))

		return atomic_read(&hctx->queue->nr_active_requests_shared_sbitmap);

	return atomic_read(&hctx->nr_active);

}

static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,

					   struct request *rq)

{
@@ -207,7 +229,7 @@ static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx, 


	if (rq->rq_flags & RQF_MQ_INFLIGHT) {

		rq->rq_flags &= ~RQF_MQ_INFLIGHT;

		atomic_dec(&hctx->nr_active);

		__blk_mq_dec_active_requests(hctx);

	}

}
@@ -287,7 +309,7 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx, 
	 * Allow at least some tags

	 */

	depth = max((bt->sb.depth + users - 1) / users, 4U);

	return atomic_read(&hctx->nr_active) < depth;

	return __blk_mq_active_requests(hctx) < depth;

}

include/linux/blkdev.h

+2 −0
Original line number Diff line number Diff line
@@ -485,6 +485,8 @@ struct request_queue { 
	struct timer_list	timeout;

	struct work_struct	timeout_work;



	atomic_t		nr_active_requests_shared_sbitmap;



	struct list_head	icq_list;

#ifdef CONFIG_BLK_CGROUP

	DECLARE_BITMAP		(blkcg_pols, BLKCG_MAX_POLS);