mlx5: Rx queue setup time determine frame_sz for XDP (d628ee4f) · Commits · 戴 / test

The mlx5 driver have multiple memory models, which are also changed according to whether a XDP bpf_prog is attached. The 'rx_striding_rq' setting is adjusted via ethtool priv-flags e.g.: # ethtool --set-priv-flags mlx5p2 rx_striding_rq off On the general case with 4K page_size and regular MTU packet, then the frame_sz is 2048 and 4096 when XDP is enabled, in both modes. The info on the given frame size is stored differently depending on the RQ-mode and encoded in a union in struct mlx5e_rq union wqe/mpwqe. In rx striding mode rq->mpwqe.log_stride_sz is either 11 or 12, which corresponds to 2048 or 4096 (MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ). In non-striding mode (MLX5_WQ_TYPE_CYCLIC) the frag_stride is stored in rq->wqe.info.arr[0].frag_stride, for the first fragment, which is what the XDP case cares about. To reduce effect on fast-path, this patch determine the frame_sz at setup time, to avoid determining the memory model runtime. Variable is named frame0_sz to make it clear that this is only the frame size of the first fragment. This mlx5 driver does a DMA-sync on XDP_TX action, but grow is safe as it have done a DMA-map on the entire PAGE_SIZE. The driver also already does a XDP length check against sq->hw_mtu on the possible XDP xmit paths mlx5e_xmit_xdp_frame() + mlx5e_xmit_xdp_frame_mpwqe(). V3+4: Change variable name first_frame_sz to frame0_sz V2: Fix that frag_size need to be recalc before creating SKB. Signed-off-by:

Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by:

Alexei Starovoitov <ast@kernel.org> Acked-by:

Tariq Toukan <tariqt@mellanox.com> Cc: Saeed Mahameed <saeedm@mellanox.com> Link: https://lore.kernel.org/bpf/158945348021.97035.12295039384250022883.stgit@firesoul

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

+1 −0

Original line number	Diff line number	Diff line
		@@ -625,6 +625,7 @@ struct mlx5e_rq {
		struct {
		u16 umem_headroom;
		u16 headroom;
		u32 frame0_sz;
		u8 map_dir; /* dma map direction */
		} buff;

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

+1 −0

Original line number	Diff line number	Diff line
		@@ -137,6 +137,7 @@ bool mlx5e_xdp_handle(struct mlx5e_rq rq, struct mlx5e_dma_info di,
		if (xsk)
		xdp.handle = di->xsk.handle;
		xdp.rxq = &rq->xdp_rxq;
		xdp.frame_sz = rq->buff.frame0_sz;

		act = bpf_prog_run_xdp(prog, &xdp);
		if (xsk) {

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

+6 −0

Original line number	Diff line number	Diff line
		@@ -462,6 +462,8 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
		rq->mpwqe.num_strides =
		BIT(mlx5e_mpwqe_get_log_num_strides(mdev, params, xsk));

		rq->buff.frame0_sz = (1 << rq->mpwqe.log_stride_sz);

		err = mlx5e_create_rq_umr_mkey(mdev, rq);
		if (err)
		goto err_rq_wq_destroy;
		@@ -485,6 +487,8 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
		num_xsk_frames = wq_sz << rq->wqe.info.log_num_frags;

		rq->wqe.info = rqp->frags_info;
		rq->buff.frame0_sz = rq->wqe.info.arr[0].frag_stride;

		rq->wqe.frags =
		kvzalloc_node(array_size(sizeof(*rq->wqe.frags),
		(wq_sz << rq->wqe.info.log_num_frags)),
		@@ -522,6 +526,8 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
		}

		if (xsk) {
		rq->buff.frame0_sz = xsk_umem_xdp_frame_sz(umem);

		err = mlx5e_xsk_resize_reuseq(umem, num_xsk_frames);
		if (unlikely(err)) {
		mlx5_core_err(mdev, "Unable to allocate the Reuse Ring for %u frames\n",

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

+2 −0

Original line number	Diff line number	Diff line
		@@ -1070,6 +1070,7 @@ mlx5e_skb_from_cqe_linear(struct mlx5e_rq rq, struct mlx5_cqe64 cqe,
		if (consumed)
		return NULL; /* page/packet was consumed by XDP */

		frag_size = MLX5_SKB_FRAG_SZ(rx_headroom + cqe_bcnt);
		skb = mlx5e_build_linear_skb(rq, va, frag_size, rx_headroom, cqe_bcnt);
		if (unlikely(!skb))
		return NULL;
		@@ -1371,6 +1372,7 @@ mlx5e_skb_from_cqe_mpwrq_linear(struct mlx5e_rq rq, struct mlx5e_mpw_info wi,
		return NULL; /* page/packet was consumed by XDP */
		}

		frag_size = MLX5_SKB_FRAG_SZ(rx_headroom + cqe_bcnt32);
		skb = mlx5e_build_linear_skb(rq, va, frag_size, rx_headroom, cqe_bcnt32);
		if (unlikely(!skb))
		return NULL;

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