Message ID | 158757178332.1370371.3518949026344543513.stgit@firesoul |
---|---|
State | Changes Requested |
Delegated to: | BPF Maintainers |
Headers | show |
Series | [net-next,01/33] xdp: add frame size to xdp_buff | expand |
On Wed, Apr 22, 2020 at 9:09 AM Jesper Dangaard Brouer <brouer@redhat.com> wrote: > > 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 first_frame_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(). > > Cc: Tariq Toukan <tariqt@mellanox.com> > Cc: Saeed Mahameed <saeedm@mellanox.com> > Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> > --- > drivers/net/ethernet/mellanox/mlx5/core/en.h | 1 + > drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 1 + > drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 6 ++++++ > 3 files changed, 8 insertions(+) Hey mellanox folks, you had an active discussion regarding mlx5 changes earlier. Were your concerns resolved ? If so, could you please ack.
On Wed, 22 Apr 2020 18:09:43 +0200 Jesper Dangaard Brouer <brouer@redhat.com> wrote: > 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 first_frame_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(). > > Cc: Tariq Toukan <tariqt@mellanox.com> > Cc: Saeed Mahameed <saeedm@mellanox.com> > Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> > --- > drivers/net/ethernet/mellanox/mlx5/core/en.h | 1 + > drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 1 + > drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 6 ++++++ > 3 files changed, 8 insertions(+) I found a bug in this patch, that can lead to BUG in skb_panic() in XDP_PASS case when growing the tail. (Hint why I fixed output in [1]). I already have a fix, but this implies I will send a V2 tomorrow. I'll pickup all the ACKs manually tomorrow, before I resubmit. [1] https://lore.kernel.org/netdev/158800546361.1962096.4535216438507756179.stgit@firesoul/
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h index 12a61bf82c14..5fa5fa891856 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h @@ -651,6 +651,7 @@ struct mlx5e_rq { struct { u16 umem_headroom; u16 headroom; + u32 first_frame_sz; u8 map_dir; /* dma map direction */ } buff; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c index f049e0ac308a..b63abaf51253 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c @@ -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.first_frame_sz; act = bpf_prog_run_xdp(prog, &xdp); if (xsk) { diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index e057822898f8..200cfd61cc54 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -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.first_frame_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.first_frame_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.first_frame_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",
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 first_frame_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(). Cc: Tariq Toukan <tariqt@mellanox.com> Cc: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> --- drivers/net/ethernet/mellanox/mlx5/core/en.h | 1 + drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 1 + drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 6 ++++++ 3 files changed, 8 insertions(+)