From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Lorenzo Bianconi <lorenzo@kernel.org>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net,
kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net,
toke@redhat.com, freysteinn.alfredsson@kau.se,
lorenzo.bianconi@redhat.com, john.fastabend@gmail.com,
jasowang@redhat.com, mst@redhat.com,
thomas.petazzoni@bootlin.com, mw@semihalf.com,
linux@armlinux.org.uk, ilias.apalodimas@linaro.org,
netanel@amazon.com, akiyano@amazon.com,
michael.chan@broadcom.com, madalin.bucur@nxp.com,
ioana.ciornei@nxp.com, jesse.brandeburg@intel.com,
anthony.l.nguyen@intel.com, saeedm@nvidia.com,
grygorii.strashko@ti.com, ecree.xilinx@gmail.com,
maciej.fijalkowski@intel.com, brouer@redhat.com
Subject: Re: [PATCH v3 bpf-next] bpf: devmap: move drop error path to devmap for XDP_REDIRECT
Date: Mon, 8 Mar 2021 15:02:11 +0100 [thread overview]
Message-ID: <20210308150211.1fffca3f@carbon> (raw)
In-Reply-To: <ed670de24f951cfd77590decf0229a0ad7fd12f6.1615201152.git.lorenzo@kernel.org>
On Mon, 8 Mar 2021 12:06:58 +0100
Lorenzo Bianconi <lorenzo@kernel.org> wrote:
> We want to change the current ndo_xdp_xmit drop semantics because
> it will allow us to implement better queue overflow handling.
> This is working towards the larger goal of a XDP TX queue-hook.
> Move XDP_REDIRECT error path handling from each XDP ethernet driver to
> devmap code. According to the new APIs, the driver running the
> ndo_xdp_xmit pointer, will break tx loop whenever the hw reports a tx
> error and it will just return to devmap caller the number of successfully
> transmitted frames. It will be devmap responsability to free dropped
> frames.
> Move each XDP ndo_xdp_xmit capable driver to the new APIs:
> - veth
> - virtio-net
> - mvneta
> - mvpp2
> - socionext
> - amazon ena
> - bnxt
> - freescale (dpaa2, dpaa)
> - xen-frontend
> - qede
> - ice
> - igb
> - ixgbe
> - i40e
> - mlx5
> - ti (cpsw, cpsw-new)
> - tun
> - sfc
>
> Acked-by: Edward Cree <ecree.xilinx@gmail.com>
> Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
> More details about the new ndo_xdp_xmit design can be found here [0].
>
> [0] https://github.com/xdp-project/xdp-project/blob/master/areas/core/redesign01_ndo_xdp_xmit.org
>
> Changes since v2:
> - drop wrong comment in ena driver
> - simplify drop condition using unlikey in the for condition of devmap code
> - rebase on top of bpf-next
> - collect acked-by/reviewed-by
>
> Changes since v1:
> - rebase on top of bpf-next
> - add driver maintainers in cc
> - add Edward's ack
> ---
> drivers/net/ethernet/amazon/ena/ena_netdev.c | 21 ++++++-------
> drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 20 +++++--------
> .../net/ethernet/freescale/dpaa/dpaa_eth.c | 12 ++++----
> .../net/ethernet/freescale/dpaa2/dpaa2-eth.c | 2 --
> drivers/net/ethernet/intel/i40e/i40e_txrx.c | 15 +++++-----
> drivers/net/ethernet/intel/ice/ice_txrx.c | 15 +++++-----
> drivers/net/ethernet/intel/igb/igb_main.c | 11 ++++---
> drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 11 ++++---
> drivers/net/ethernet/marvell/mvneta.c | 13 ++++----
> .../net/ethernet/marvell/mvpp2/mvpp2_main.c | 13 ++++----
> .../net/ethernet/mellanox/mlx5/core/en/xdp.c | 15 ++++------
> drivers/net/ethernet/qlogic/qede/qede_fp.c | 19 +++++-------
> drivers/net/ethernet/sfc/tx.c | 15 +---------
> drivers/net/ethernet/socionext/netsec.c | 16 +++++-----
> drivers/net/ethernet/ti/cpsw.c | 14 ++++-----
> drivers/net/ethernet/ti/cpsw_new.c | 14 ++++-----
> drivers/net/ethernet/ti/cpsw_priv.c | 11 +++----
> drivers/net/tun.c | 15 ++++++----
> drivers/net/veth.c | 28 +++++++++--------
> drivers/net/virtio_net.c | 25 ++++++++--------
> drivers/net/xen-netfront.c | 18 +++++------
> kernel/bpf/devmap.c | 30 ++++++++-----------
> 22 files changed, 153 insertions(+), 200 deletions(-)
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acking core changes to bpf/devmap.c (kept below).
I've only skimmed the driver changes.
> diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
> index 85d9d1b72a33..d6330bbe1209 100644
> --- a/kernel/bpf/devmap.c
> +++ b/kernel/bpf/devmap.c
> @@ -330,7 +330,7 @@ bool dev_map_can_have_prog(struct bpf_map *map)
> static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags)
> {
> struct net_device *dev = bq->dev;
> - int sent = 0, drops = 0, err = 0;
> + int sent = 0, err = 0;
> int i;
>
> if (unlikely(!bq->count))
> @@ -344,29 +344,23 @@ static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags)
>
> sent = dev->netdev_ops->ndo_xdp_xmit(dev, bq->count, bq->q, flags);
> if (sent < 0) {
> + /* If ndo_xdp_xmit fails with an errno, no frames have
> + * been xmit'ed.
> + */
> err = sent;
> sent = 0;
> - goto error;
> }
> - drops = bq->count - sent;
> -out:
> - bq->count = 0;
>
> - trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, drops, err);
> - bq->dev_rx = NULL;
> - __list_del_clearprev(&bq->flush_node);
> - return;
> -error:
> - /* If ndo_xdp_xmit fails with an errno, no frames have been
> - * xmit'ed and it's our responsibility to them free all.
> + /* If not all frames have been transmitted, it is our
> + * responsibility to free them
> */
> - for (i = 0; i < bq->count; i++) {
> - struct xdp_frame *xdpf = bq->q[i];
> + for (i = sent; unlikely(i < bq->count); i++)
> + xdp_return_frame_rx_napi(bq->q[i]);
>
> - xdp_return_frame_rx_napi(xdpf);
> - drops++;
> - }
> - goto out;
> + trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, bq->count - sent, err);
> + bq->dev_rx = NULL;
> + bq->count = 0;
> + __list_del_clearprev(&bq->flush_node);
> }
>
> /* __dev_flush is called from xdp_do_flush() which _must_ be signaled
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2021-03-08 14:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-08 11:06 [PATCH v3 bpf-next] bpf: devmap: move drop error path to devmap for XDP_REDIRECT Lorenzo Bianconi
2021-03-08 13:46 ` Camelia Alexandra Groza
2021-03-08 14:02 ` Jesper Dangaard Brouer [this message]
2021-03-08 16:15 ` Shay Agroskin
2021-03-18 15:47 ` Daniel Borkmann
2021-03-18 15:50 ` patchwork-bot+netdevbpf
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