Commit e7e0004a authored by Maxim Mikityanskiy's avatar Maxim Mikityanskiy Committed by Saeed Mahameed
Browse files

net/mlx5e: Don't trigger IRQ multiple times on XSK wakeup to avoid WQ overruns 



XSK wakeup function triggers NAPI by posting a NOP WQE to a special XSK
ICOSQ. When the application floods the driver with wakeup requests by
calling sendto() in a certain pattern that ends up in mlx5e_trigger_irq,
the XSK ICOSQ may overflow.

Multiple NOPs are not required and won't accelerate the process, so
avoid posting a second NOP if there is one already on the way. This way
we also avoid increasing the queue size (which might not help anyway).

Fixes: db05815b ("net/mlx5e: Add XSK zero-copy support")
Signed-off-by: default avatarMaxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: default avatarTariq Toukan <tariqt@mellanox.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
parent 70840b66

drivers/net/ethernet/mellanox/mlx5/core/en.h

+2 −1
Original line number Diff line number Diff line
@@ -367,6 +367,7 @@ enum { 
	MLX5E_SQ_STATE_AM,

	MLX5E_SQ_STATE_TLS,

	MLX5E_SQ_STATE_VLAN_NEED_L2_INLINE,

	MLX5E_SQ_STATE_PENDING_XSK_TX,

};



struct mlx5e_sq_wqe_info {
@@ -960,7 +961,7 @@ void mlx5e_page_release_dynamic(struct mlx5e_rq *rq, 
void mlx5e_handle_rx_cqe(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe);

void mlx5e_handle_rx_cqe_mpwrq(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe);

bool mlx5e_post_rx_wqes(struct mlx5e_rq *rq);

void mlx5e_poll_ico_cq(struct mlx5e_cq *cq);

int mlx5e_poll_ico_cq(struct mlx5e_cq *cq);

bool mlx5e_post_rx_mpwqes(struct mlx5e_rq *rq);

void mlx5e_dealloc_rx_wqe(struct mlx5e_rq *rq, u16 ix);

void mlx5e_dealloc_rx_mpwqe(struct mlx5e_rq *rq, u16 ix);

drivers/net/ethernet/mellanox/mlx5/core/en/xsk/tx.c

+3 −0
Original line number Diff line number Diff line
@@ -33,6 +33,9 @@ int mlx5e_xsk_wakeup(struct net_device *dev, u32 qid, u32 flags) 
		if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &c->xskicosq.state)))

			return 0;



		if (test_and_set_bit(MLX5E_SQ_STATE_PENDING_XSK_TX, &c->xskicosq.state))

			return 0;



		spin_lock(&c->xskicosq_lock);

		mlx5e_trigger_irq(&c->xskicosq);

		spin_unlock(&c->xskicosq_lock);

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

+5 −3
Original line number Diff line number Diff line
@@ -589,7 +589,7 @@ bool mlx5e_post_rx_wqes(struct mlx5e_rq *rq) 
	return !!err;

}



void mlx5e_poll_ico_cq(struct mlx5e_cq *cq)

int mlx5e_poll_ico_cq(struct mlx5e_cq *cq)

{

	struct mlx5e_icosq *sq = container_of(cq, struct mlx5e_icosq, cq);

	struct mlx5_cqe64 *cqe;
@@ -597,11 +597,11 @@ void mlx5e_poll_ico_cq(struct mlx5e_cq *cq) 
	int i;



	if (unlikely(!test_bit(MLX5E_SQ_STATE_ENABLED, &sq->state)))

		return;

		return 0;



	cqe = mlx5_cqwq_get_cqe(&cq->wq);

	if (likely(!cqe))

		return;

		return 0;



	/* sq->cc must be updated only after mlx5_cqwq_update_db_record(),

	 * otherwise a cq overrun may occur
@@ -650,6 +650,8 @@ void mlx5e_poll_ico_cq(struct mlx5e_cq *cq) 
	sq->cc = sqcc;



	mlx5_cqwq_update_db_record(&cq->wq);



	return i;

}



bool mlx5e_post_rx_mpwqes(struct mlx5e_rq *rq)

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

+5 −1
Original line number Diff line number Diff line
@@ -152,7 +152,11 @@ int mlx5e_napi_poll(struct napi_struct *napi, int budget) 
				mlx5e_post_rx_wqes,

				rq);

	if (xsk_open) {

		mlx5e_poll_ico_cq(&c->xskicosq.cq);

		if (mlx5e_poll_ico_cq(&c->xskicosq.cq))

			/* Don't clear the flag if nothing was polled to prevent

			 * queueing more WQEs and overflowing XSKICOSQ.

			 */

			clear_bit(MLX5E_SQ_STATE_PENDING_XSK_TX, &c->xskicosq.state);

		busy |= mlx5e_poll_xdpsq_cq(&xsksq->cq);

		busy_xsk |= mlx5e_napi_xsk_post(xsksq, xskrq);

	}

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