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Commit dac0d15f authored by Tariq Toukan's avatar Tariq Toukan Committed by Saeed Mahameed
Browse files

net/mlx5e: Re-order fields of struct mlx5e_xdpsq 



In the downstream patch that adds support to XDP_REDIRECT-out,
the XDP xmit frame function doesn't share the same run context as
the NAPI that polls the XDP-SQ completion queue.

Hence, need to re-order the XDP-SQ fields to avoid cacheline
false-sharing.

Take redirect_flush and doorbell out of DB, into separated
cachelines.

Add a cacheline breaker within the stats struct.

Signed-off-by: default avatarTariq Toukan <tariqt@mellanox.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@mellanox.com>
parent 890388ad

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

+9 −9
Original line number Diff line number Diff line
@@ -409,22 +409,22 @@ struct mlx5e_xdp_info { 
struct mlx5e_xdpsq {

	/* data path */



	/* dirtied @rx completion */

	/* dirtied @completion */

	u16                        cc;

	u16                        pc;



	struct mlx5e_cq            cq;

	bool                       redirect_flush;



	/* write@xmit, read@completion */

	struct {

		struct mlx5e_xdp_info     *xdpi;

	/* dirtied @xmit */

	u16                        pc ____cacheline_aligned_in_smp;

	bool                       doorbell;

		bool                       redirect_flush;

	} db;



	struct mlx5e_cq            cq;



	/* read only */

	struct mlx5_wq_cyc         wq;

	struct mlx5e_xdpsq_stats  *stats;

	struct {

		struct mlx5e_xdp_info     *xdpi;

	} db;

	void __iomem              *uar_map;

	u32                        sqn;

	struct device             *pdev;

drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c

+4 −4
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ bool mlx5e_xdp_handle(struct mlx5e_rq *rq, struct mlx5e_dma_info *di, 
		if (unlikely(err))

			goto xdp_abort;

		__set_bit(MLX5E_RQ_FLAG_XDP_XMIT, rq->flags);

		rq->xdpsq.db.redirect_flush = true;

		rq->xdpsq.redirect_flush = true;

		mlx5e_page_dma_unmap(rq, di);

		rq->stats->xdp_redirect++;

		return true;
@@ -124,10 +124,10 @@ bool mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xdp_info *xdpi) 
	}



	if (unlikely(!mlx5e_wqc_has_room_for(wq, sq->cc, sq->pc, 1))) {

		if (sq->db.doorbell) {

		if (sq->doorbell) {

			/* SQ is full, ring doorbell */

			mlx5e_xmit_xdp_doorbell(sq);

			sq->db.doorbell = false;

			sq->doorbell = false;

		}

		stats->full++;

		return false;
@@ -156,7 +156,7 @@ bool mlx5e_xmit_xdp_frame(struct mlx5e_xdpsq *sq, struct mlx5e_xdp_info *xdpi) 
	sq->db.xdpi[pi] = *xdpi;

	sq->pc++;



	sq->db.doorbell = true;

	sq->doorbell = true;



	stats->xmit++;

	return true;

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

+4 −4
Original line number Diff line number Diff line
@@ -1201,14 +1201,14 @@ int mlx5e_poll_rx_cq(struct mlx5e_cq *cq, int budget) 
		rq->handle_rx_cqe(rq, cqe);

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



	if (xdpsq->db.doorbell) {

	if (xdpsq->doorbell) {

		mlx5e_xmit_xdp_doorbell(xdpsq);

		xdpsq->db.doorbell = false;

		xdpsq->doorbell = false;

	}



	if (xdpsq->db.redirect_flush) {

	if (xdpsq->redirect_flush) {

		xdp_do_flush_map();

		xdpsq->db.redirect_flush = false;

		xdpsq->redirect_flush = false;

	}



	mlx5_cqwq_update_db_record(&cq->wq);

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

+2 −1
Original line number Diff line number Diff line
@@ -230,7 +230,8 @@ struct mlx5e_xdpsq_stats { 
	u64 xmit;

	u64 full;

	u64 err;

	u64 cqes;

	/* dirtied @completion */

	u64 cqes ____cacheline_aligned_in_smp;

};



struct mlx5e_ch_stats {