Commit bb94aea1 authored by Jianchao Wang's avatar Jianchao Wang Committed by Jens Axboe
Browse files

blk-mq: save default hctx into ctx->hctxs for not-supported type 



Currently, we check whether the hctx type is supported every time
in hot path. Actually, this is not necessary, we could save the
default hctx into ctx->hctxs if the type is not supported when
map swqueues and use it directly with ctx->hctxs[type].

We also needn't check whether the poll is enabled or not, because
the caller would clear the REQ_HIPRI in that case.

Signed-off-by: default avatarJianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8ccdf4a3

block/blk-mq.c

+8 −1
Original line number Diff line number Diff line
@@ -2431,8 +2431,11 @@ static void blk_mq_map_swqueue(struct request_queue *q) 


		ctx = per_cpu_ptr(q->queue_ctx, i);

		for (j = 0; j < set->nr_maps; j++) {

			if (!set->map[j].nr_queues)

			if (!set->map[j].nr_queues) {

				ctx->hctxs[j] = blk_mq_map_queue_type(q,

						HCTX_TYPE_DEFAULT, i);

				continue;

			}



			hctx = blk_mq_map_queue_type(q, j, i);

			ctx->hctxs[j] = hctx;
@@ -2455,6 +2458,10 @@ static void blk_mq_map_swqueue(struct request_queue *q) 
			 */

			BUG_ON(!hctx->nr_ctx);

		}



		for (; j < HCTX_MAX_TYPES; j++)

			ctx->hctxs[j] = blk_mq_map_queue_type(q,

					HCTX_TYPE_DEFAULT, i);

	}



	mutex_unlock(&q->sysfs_lock);

block/blk-mq.h

+5 −8
Original line number Diff line number Diff line
@@ -106,15 +106,12 @@ static inline struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q, 
{

	enum hctx_type type = HCTX_TYPE_DEFAULT;



	if ((flags & REQ_HIPRI) &&

	    q->tag_set->nr_maps > HCTX_TYPE_POLL && 

	    q->tag_set->map[HCTX_TYPE_POLL].nr_queues &&

	    test_bit(QUEUE_FLAG_POLL, &q->queue_flags))

	/*

	 * The caller ensure that if REQ_HIPRI, poll must be enabled.

	 */

	if (flags & REQ_HIPRI)

		type = HCTX_TYPE_POLL;



	else if (((flags & REQ_OP_MASK) == REQ_OP_READ) &&

	         q->tag_set->nr_maps > HCTX_TYPE_READ &&

		 q->tag_set->map[HCTX_TYPE_READ].nr_queues)

	else if ((flags & REQ_OP_MASK) == REQ_OP_READ)

		type = HCTX_TYPE_READ;

	

	return ctx->hctxs[type];

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