Commit 86f767e6 authored by Lang Cheng's avatar Lang Cheng Committed by Jason Gunthorpe
Browse files

RDMA/hns: Replace wmb&__raw_writeq with writeq 

Currently, the driver updates doorbell looks like this:

post()
{
	wqe.field = 0x111;
	wmb();
	update_wq_db();
}

update_wq_db()
{
	db.field = 0x222;
	__raw_writeq(db, db_reg);
}

writeq() is a better choice than __raw_writeq() because it calls dma_wmb()
to barrier in ARM64, and dma_wmb() is better than wmb() for ROCEE device.

This patch removes all wmb() before updating doorbell of SQ/RQ/CQ/SRQ by
replacing __raw_writeq() with writeq() to improve performence.  The new
process looks like this:

post()
{
	wqe.field = 0x111;
	update_wq_db();
}

update_wq_db()
{
	db.field = 0x222;
	writeq(db, db_reg);
}

Link: https://lore.kernel.org/r/1612517974-31867-8-git-send-email-liweihang@huawei.com


Signed-off-by: default avatarLang Cheng <chenglang@huawei.com>
Signed-off-by: default avatarWeihang Li <liweihang@huawei.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 3fe07a00

drivers/infiniband/hw/hns/hns_roce_device.h

+1 −1
Original line number Diff line number Diff line
@@ -1077,7 +1077,7 @@ static inline struct hns_roce_srq *to_hr_srq(struct ib_srq *ibsrq) 


static inline void hns_roce_write64_k(__le32 val[2], void __iomem *dest)

{

	__raw_writeq(*(u64 *) val, dest);

	writeq(*(u64 *)val, dest);

}



static inline struct hns_roce_qp

drivers/infiniband/hw/hns/hns_roce_hw_v1.c

+0 −15
Original line number Diff line number Diff line
@@ -330,8 +330,6 @@ static int hns_roce_v1_post_send(struct ib_qp *ibqp, 
	/* Set DB return */

	if (likely(nreq)) {

		qp->sq.head += nreq;

		/* Memory barrier */

		wmb();



		roce_set_field(sq_db.u32_4, SQ_DOORBELL_U32_4_SQ_HEAD_M,

			       SQ_DOORBELL_U32_4_SQ_HEAD_S,
@@ -411,8 +409,6 @@ static int hns_roce_v1_post_recv(struct ib_qp *ibqp, 
out:

	if (likely(nreq)) {

		hr_qp->rq.head += nreq;

		/* Memory barrier */

		wmb();



		if (ibqp->qp_type == IB_QPT_GSI) {

			__le32 tmp;
@@ -1984,12 +1980,6 @@ static void __hns_roce_v1_cq_clean(struct hns_roce_cq *hr_cq, u32 qpn, 


	if (nfreed) {

		hr_cq->cons_index += nfreed;

		/*

		 * Make sure update of buffer contents is done before

		 * updating consumer index.

		 */

		wmb();



		hns_roce_v1_cq_set_ci(hr_cq, hr_cq->cons_index);

	}

}
@@ -2330,8 +2320,6 @@ int hns_roce_v1_poll_cq(struct ib_cq *ibcq, int num_entries, struct ib_wc *wc) 
		*hr_cq->tptr_addr = hr_cq->cons_index &

			((hr_cq->cq_depth << 1) - 1);



		/* Memroy barrier */

		wmb();

		hns_roce_v1_cq_set_ci(hr_cq, hr_cq->cons_index);

	}
@@ -3220,9 +3208,6 @@ static int hns_roce_v1_m_qp(struct ib_qp *ibqp, const struct ib_qp_attr *attr, 
	 * need to hw to flash RQ HEAD by DB again

	 */

	if (cur_state == IB_QPS_INIT && new_state == IB_QPS_INIT) {

		/* Memory barrier */

		wmb();



		roce_set_field(doorbell[0], RQ_DOORBELL_U32_4_RQ_HEAD_M,

			       RQ_DOORBELL_U32_4_RQ_HEAD_S, hr_qp->rq.head);

		roce_set_field(doorbell[1], RQ_DOORBELL_U32_8_QPN_M,

drivers/infiniband/hw/hns/hns_roce_hw_v2.c

+1 −19
Original line number Diff line number Diff line
@@ -744,8 +744,6 @@ static int hns_roce_v2_post_send(struct ib_qp *ibqp, 
	if (likely(nreq)) {

		qp->sq.head += nreq;

		qp->next_sge = sge_idx;

		/* Memory barrier */

		wmb();



		if (nreq == 1 && qp->sq.head == qp->sq.tail + 1 &&

		    (qp->en_flags & HNS_ROCE_QP_CAP_DIRECT_WQE))
@@ -875,8 +873,6 @@ static int hns_roce_v2_post_recv(struct ib_qp *ibqp, 
out:

	if (likely(nreq)) {

		hr_qp->rq.head += nreq;

		/* Memory barrier */

		wmb();



		/*

		 * Hip08 hardware cannot flush the WQEs in RQ if the QP state
@@ -1015,12 +1011,6 @@ static int hns_roce_v2_post_srq_recv(struct ib_srq *ibsrq, 
	}



	if (likely(nreq)) {

		/*

		 * Make sure that descriptors are written before

		 * doorbell record.

		 */

		wmb();



		srq_db.byte_4 =

			cpu_to_le32(HNS_ROCE_V2_SRQ_DB << V2_DB_BYTE_4_CMD_S |

				    (srq->srqn & V2_DB_BYTE_4_TAG_M));
@@ -3198,11 +3188,6 @@ static void __hns_roce_v2_cq_clean(struct hns_roce_cq *hr_cq, u32 qpn, 


	if (nfreed) {

		hr_cq->cons_index += nfreed;

		/*

		 * Make sure update of buffer contents is done before

		 * updating consumer index.

		 */

		wmb();

		hns_roce_v2_cq_set_ci(hr_cq, hr_cq->cons_index);

	}

}
@@ -3711,11 +3696,8 @@ static int hns_roce_v2_poll_cq(struct ib_cq *ibcq, int num_entries, 
			break;

	}



	if (npolled) {

		/* Memory barrier */

		wmb();

	if (npolled)

		hns_roce_v2_cq_set_ci(hr_cq, hr_cq->cons_index);

	}



out:

	spin_unlock_irqrestore(&hr_cq->lock, flags);