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Commit 4b7dfc99 authored by Tariq Toukan's avatar Tariq Toukan Committed by Saeed Mahameed
Browse files

net/mlx5e: Early-return on empty completion queues 



NAPI context handles different kinds of completion queues
(RX, TX, and others). Hence, upon a poll trial, some of them
might be empty.
Here we early-return upon empty completion queues, as well as
full rx buffer, and save unnecessary logic and memory barriers.

Signed-off-by: default avatarTariq Toukan <tariqt@mellanox.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
parent 4cbb7558

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

+23 −17
Original line number Diff line number Diff line
@@ -459,16 +459,19 @@ void mlx5e_dealloc_rx_mpwqe(struct mlx5e_rq *rq, u16 ix) 
bool mlx5e_post_rx_wqes(struct mlx5e_rq *rq)

{

	struct mlx5_wq_ll *wq = &rq->wq;

	int err;



	if (unlikely(!test_bit(MLX5E_RQ_STATE_ENABLED, &rq->state)))

		return false;



	if (mlx5_wq_ll_is_full(wq))

		return false;



	if (test_bit(MLX5E_RQ_STATE_UMR_WQE_IN_PROGRESS, &rq->state))

		return true;



	while (!mlx5_wq_ll_is_full(wq)) {

	do {

		struct mlx5e_rx_wqe *wqe = mlx5_wq_ll_get_wqe(wq, wq->head);

		int err;



		err = rq->alloc_wqe(rq, wqe, wq->head);

		if (err == -EBUSY)
@@ -479,14 +482,14 @@ bool mlx5e_post_rx_wqes(struct mlx5e_rq *rq) 
		}



		mlx5_wq_ll_push(wq, be16_to_cpu(wqe->next.next_wqe_index));

	}

	} while (!mlx5_wq_ll_is_full(wq));



	/* ensure wqes are visible to device before updating doorbell record */

	dma_wmb();



	mlx5_wq_ll_update_db_record(wq);



	return !mlx5_wq_ll_is_full(wq);

	return !!err;

}



static void mlx5e_lro_update_hdr(struct sk_buff *skb, struct mlx5_cqe64 *cqe,
@@ -981,7 +984,8 @@ void mlx5e_handle_rx_cqe_mpwrq(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe) 
int mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget)

{

	struct mlx5e_rq *rq = container_of(cq, struct mlx5e_rq, cq);

	struct mlx5e_xdpsq *xdpsq = &rq->xdpsq;

	struct mlx5e_xdpsq *xdpsq;

	struct mlx5_cqe64 *cqe;

	int work_done = 0;



	if (unlikely(!test_bit(MLX5E_RQ_STATE_ENABLED, &rq->state)))
@@ -990,12 +994,13 @@ int mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget) 
	if (cq->decmprs_left)

		work_done += mlx5e_decompress_cqes_cont(rq, cq, 0, budget);



	for (; work_done < budget; work_done++) {

		struct mlx5_cqe64 *cqe = mlx5_cqwq_get_cqe(&cq->wq);



	cqe = mlx5_cqwq_get_cqe(&cq->wq);

	if (!cqe)

			break;

		return 0;



	xdpsq = &rq->xdpsq;



	do {

		if (mlx5_get_cqe_format(cqe) == MLX5_COMPRESSED) {

			work_done +=

				mlx5e_decompress_cqes_start(rq, cq,
@@ -1006,7 +1011,7 @@ int mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget) 
		mlx5_cqwq_pop(&cq->wq);



		rq->handle_rx_cqe(rq, cqe);

	}

	} while ((++work_done < budget) && (cqe = mlx5_cqwq_get_cqe(&cq->wq)));



	if (xdpsq->db.doorbell) {

		mlx5e_xmit_xdp_doorbell(xdpsq);
@@ -1024,6 +1029,7 @@ int mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget) 
bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq)

{

	struct mlx5e_xdpsq *sq;

	struct mlx5_cqe64 *cqe;

	struct mlx5e_rq *rq;

	u16 sqcc;

	int i;
@@ -1033,6 +1039,10 @@ bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq) 
	if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &sq->state)))

		return false;



	cqe = mlx5_cqwq_get_cqe(&cq->wq);

	if (!cqe)

		return false;



	rq = container_of(sq, struct mlx5e_rq, xdpsq);



	/* sq->cc must be updated only after mlx5_cqwq_update_db_record(),
@@ -1040,15 +1050,11 @@ bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq) 
	 */

	sqcc = sq->cc;



	for (i = 0; i < MLX5E_TX_CQ_POLL_BUDGET; i++) {

		struct mlx5_cqe64 *cqe;

	i = 0;

	do {

		u16 wqe_counter;

		bool last_wqe;



		cqe = mlx5_cqwq_get_cqe(&cq->wq);

		if (!cqe)

			break;



		mlx5_cqwq_pop(&cq->wq);



		wqe_counter = be16_to_cpu(cqe->wqe_counter);
@@ -1066,7 +1072,7 @@ bool mlx5e_poll_xdpsq_cq(struct mlx5e_cq *cq) 
			/* Recycle RX page */

			mlx5e_page_release(rq, di, true);

		} while (!last_wqe);

	}

	} while ((++i < MLX5E_TX_CQ_POLL_BUDGET) && (cqe = mlx5_cqwq_get_cqe(&cq->wq)));



	mlx5_cqwq_update_db_record(&cq->wq);

drivers/net/ethernet/mellanox/mlx5/core/en_tx.c

+9 −7
Original line number Diff line number Diff line
@@ -394,6 +394,7 @@ netdev_tx_t mlx5e_xmit(struct sk_buff *skb, struct net_device *dev) 
bool mlx5e_poll_tx_cq(struct mlx5e_cq *cq, int napi_budget)

{

	struct mlx5e_txqsq *sq;

	struct mlx5_cqe64 *cqe;

	u32 dma_fifo_cc;

	u32 nbytes;

	u16 npkts;
@@ -405,6 +406,10 @@ bool mlx5e_poll_tx_cq(struct mlx5e_cq *cq, int napi_budget) 
	if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &sq->state)))

		return false;



	cqe = mlx5_cqwq_get_cqe(&cq->wq);

	if (!cqe)

		return false;



	npkts = 0;

	nbytes = 0;
@@ -416,15 +421,11 @@ bool mlx5e_poll_tx_cq(struct mlx5e_cq *cq, int napi_budget) 
	/* avoid dirtying sq cache line every cqe */

	dma_fifo_cc = sq->dma_fifo_cc;



	for (i = 0; i < MLX5E_TX_CQ_POLL_BUDGET; i++) {

		struct mlx5_cqe64 *cqe;

	i = 0;

	do {

		u16 wqe_counter;

		bool last_wqe;



		cqe = mlx5_cqwq_get_cqe(&cq->wq);

		if (!cqe)

			break;



		mlx5_cqwq_pop(&cq->wq);



		wqe_counter = be16_to_cpu(cqe->wqe_counter);
@@ -467,7 +468,8 @@ bool mlx5e_poll_tx_cq(struct mlx5e_cq *cq, int napi_budget) 
			sqcc += wi->num_wqebbs;

			napi_consume_skb(skb, napi_budget);

		} while (!last_wqe);

	}



	} while ((++i < MLX5E_TX_CQ_POLL_BUDGET) && (cqe = mlx5_cqwq_get_cqe(&cq->wq)));



	mlx5_cqwq_update_db_record(&cq->wq);