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Message-Id: <20200928.125508.458441817113961397.davem@davemloft.net>
Date: Mon, 28 Sep 2020 12:55:08 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: anthony.l.nguyen@...el.com
Cc: sven.auhagen@...eatech.de, netdev@...r.kernel.org,
nhorman@...hat.com, sassmann@...hat.com,
sandeep.penigalapati@...el.com
Subject: Re: [net-next 01/15] igb: add XDP support
From: Tony Nguyen <anthony.l.nguyen@...el.com>
Date: Mon, 28 Sep 2020 10:58:54 -0700
> From: Sven Auhagen <sven.auhagen@...eatech.de>
>
> Add XDP support to the IGB driver.
> The implementation follows the IXGBE XDP implementation
> closely and I used the following patches as basis:
>
> 1. commit 924708081629 ("ixgbe: add XDP support for pass and drop actions")
> 2. commit 33fdc82f0883 ("ixgbe: add support for XDP_TX action")
> 3. commit ed93a3987128 ("ixgbe: tweak page counting for XDP_REDIRECT")
>
> Due to the hardware constraints of the devices using the
> IGB driver we must share the TX queues with XDP which
> means locking the TX queue for XDP.
>
> I ran tests on an older device to get better numbers.
> Test machine:
>
> Intel(R) Atom(TM) CPU C2338 @ 1.74GHz (2 Cores)
> 2x Intel I211
>
> Routing Original Driver Network Stack: 382 Kpps
>
> Routing XDP Redirect (xdp_fwd_kern): 1.48 Mpps
> XDP Drop: 1.48 Mpps
>
> Using XDP we can achieve line rate forwarding even on
> an older Intel Atom CPU.
>
> Signed-off-by: Sven Auhagen <sven.auhagen@...eatech.de>
> Tested-by: Sandeep Penigalapati <sandeep.penigalapati@...el.com>
> Signed-off-by: Tony Nguyen <anthony.l.nguyen@...el.com>
> ---
> drivers/net/ethernet/intel/igb/igb.h | 80 +++-
> drivers/net/ethernet/intel/igb/igb_ethtool.c | 4 +
> drivers/net/ethernet/intel/igb/igb_main.c | 433 +++++++++++++++++--
> 3 files changed, 481 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
> index 2f015b60a995..0286d2fceee4 100644
> --- a/drivers/net/ethernet/intel/igb/igb.h
> +++ b/drivers/net/ethernet/intel/igb/igb.h
> @@ -19,6 +19,8 @@
> #include <linux/pci.h>
> #include <linux/mdio.h>
>
> +#include <net/xdp.h>
> +
> struct igb_adapter;
>
> #define E1000_PCS_CFG_IGN_SD 1
> @@ -79,6 +81,12 @@ struct igb_adapter;
> #define IGB_I210_RX_LATENCY_100 2213
> #define IGB_I210_RX_LATENCY_1000 448
>
> +/* XDP */
> +#define IGB_XDP_PASS 0
> +#define IGB_XDP_CONSUMED BIT(0)
> +#define IGB_XDP_TX BIT(1)
> +#define IGB_XDP_REDIR BIT(2)
> +
> struct vf_data_storage {
> unsigned char vf_mac_addresses[ETH_ALEN];
> u16 vf_mc_hashes[IGB_MAX_VF_MC_ENTRIES];
> @@ -132,17 +140,62 @@ struct vf_mac_filter {
>
> /* Supported Rx Buffer Sizes */
> #define IGB_RXBUFFER_256 256
> +#define IGB_RXBUFFER_1536 1536
> #define IGB_RXBUFFER_2048 2048
> #define IGB_RXBUFFER_3072 3072
> #define IGB_RX_HDR_LEN IGB_RXBUFFER_256
> #define IGB_TS_HDR_LEN 16
>
> -#define IGB_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
> +/* Attempt to maximize the headroom available for incoming frames. We
> + * use a 2K buffer for receives and need 1536/1534 to store the data for
> + * the frame. This leaves us with 512 bytes of room. From that we need
> + * to deduct the space needed for the shared info and the padding needed
> + * to IP align the frame.
> + *
> + * Note: For cache line sizes 256 or larger this value is going to end
> + * up negative. In these cases we should fall back to the 3K
> + * buffers.
> + */
> #if (PAGE_SIZE < 8192)
> -#define IGB_MAX_FRAME_BUILD_SKB \
> - (SKB_WITH_OVERHEAD(IGB_RXBUFFER_2048) - IGB_SKB_PAD - IGB_TS_HDR_LEN)
> +#define IGB_MAX_FRAME_BUILD_SKB (IGB_RXBUFFER_1536 - NET_IP_ALIGN)
> +#define IGB_2K_TOO_SMALL_WITH_PADDING \
> +((NET_SKB_PAD + IGB_TS_HDR_LEN + IGB_RXBUFFER_1536) > SKB_WITH_OVERHEAD(IGB_RXBUFFER_2048))
> +
> +static inline int igb_compute_pad(int rx_buf_len)
> +{
> + int page_size, pad_size;
> +
> + page_size = ALIGN(rx_buf_len, PAGE_SIZE / 2);
> + pad_size = SKB_WITH_OVERHEAD(page_size) - rx_buf_len;
> +
> + return pad_size;
> +}
> +
> +static inline int igb_skb_pad(void)
> +{
> + int rx_buf_len;
> +
> + /* If a 2K buffer cannot handle a standard Ethernet frame then
> + * optimize padding for a 3K buffer instead of a 1.5K buffer.
> + *
> + * For a 3K buffer we need to add enough padding to allow for
> + * tailroom due to NET_IP_ALIGN possibly shifting us out of
> + * cache-line alignment.
> + */
> + if (IGB_2K_TOO_SMALL_WITH_PADDING)
> + rx_buf_len = IGB_RXBUFFER_3072 + SKB_DATA_ALIGN(NET_IP_ALIGN);
> + else
> + rx_buf_len = IGB_RXBUFFER_1536;
> +
> + /* if needed make room for NET_IP_ALIGN */
> + rx_buf_len -= NET_IP_ALIGN;
> +
> + return igb_compute_pad(rx_buf_len);
> +}
> +
> +#define IGB_SKB_PAD igb_skb_pad()
> #else
> -#define IGB_MAX_FRAME_BUILD_SKB (IGB_RXBUFFER_2048 - IGB_TS_HDR_LEN)
> +#define IGB_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
> #endif
>
> /* How many Rx Buffers do we bundle into one write to the hardware ? */
> @@ -194,13 +247,22 @@ enum igb_tx_flags {
> #define IGB_SFF_ADDRESSING_MODE 0x4
> #define IGB_SFF_8472_UNSUP 0x00
>
> +enum igb_tx_buf_type {
> + IGB_TYPE_SKB = 0,
> + IGB_TYPE_XDP,
> +};
> +
> /* wrapper around a pointer to a socket buffer,
> * so a DMA handle can be stored along with the buffer
> */
> struct igb_tx_buffer {
> union e1000_adv_tx_desc *next_to_watch;
> unsigned long time_stamp;
> - struct sk_buff *skb;
> + enum igb_tx_buf_type type;
> + union {
> + struct sk_buff *skb;
> + struct xdp_frame *xdpf;
> + };
> unsigned int bytecount;
> u16 gso_segs;
> __be16 protocol;
> @@ -248,6 +310,7 @@ struct igb_ring_container {
> struct igb_ring {
> struct igb_q_vector *q_vector; /* backlink to q_vector */
> struct net_device *netdev; /* back pointer to net_device */
> + struct bpf_prog *xdp_prog;
> struct device *dev; /* device pointer for dma mapping */
> union { /* array of buffer info structs */
> struct igb_tx_buffer *tx_buffer_info;
> @@ -288,6 +351,7 @@ struct igb_ring {
> struct u64_stats_sync rx_syncp;
> };
> };
> + struct xdp_rxq_info xdp_rxq;
> } ____cacheline_internodealigned_in_smp;
>
> struct igb_q_vector {
> @@ -339,7 +403,7 @@ static inline unsigned int igb_rx_bufsz(struct igb_ring *ring)
> return IGB_RXBUFFER_3072;
>
> if (ring_uses_build_skb(ring))
> - return IGB_MAX_FRAME_BUILD_SKB + IGB_TS_HDR_LEN;
> + return IGB_MAX_FRAME_BUILD_SKB;
> #endif
> return IGB_RXBUFFER_2048;
> }
> @@ -467,6 +531,7 @@ struct igb_adapter {
> unsigned long active_vlans[BITS_TO_LONGS(VLAN_N_VID)];
>
> struct net_device *netdev;
> + struct bpf_prog *xdp_prog;
>
> unsigned long state;
> unsigned int flags;
> @@ -643,6 +708,9 @@ enum igb_boards {
>
> extern char igb_driver_name[];
>
> +int igb_xmit_xdp_ring(struct igb_adapter *adapter,
> + struct igb_ring *ring,
> + struct xdp_frame *xdpf);
> int igb_open(struct net_device *netdev);
> int igb_close(struct net_device *netdev);
> int igb_up(struct igb_adapter *);
> diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> index 6e8231c1ddf0..28baf203459a 100644
> --- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
> +++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> @@ -961,6 +961,10 @@ static int igb_set_ringparam(struct net_device *netdev,
> memcpy(&temp_ring[i], adapter->rx_ring[i],
> sizeof(struct igb_ring));
>
> + /* Clear copied XDP RX-queue info */
> + memset(&temp_ring[i].xdp_rxq, 0,
> + sizeof(temp_ring[i].xdp_rxq));
> +
> temp_ring[i].count = new_rx_count;
> err = igb_setup_rx_resources(&temp_ring[i]);
> if (err) {
> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> index 44157fcd3cf7..73125d11460f 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
...
> +static inline struct igb_ring *igb_xdp_tx_queue_mapping(struct igb_adapter *adapter)
> +{
Please do not use inline in foo.c files, let the compiler decide.
> @@ -8282,6 +8610,11 @@ static void igb_process_skb_fields(struct igb_ring *rx_ring,
> skb->protocol = eth_type_trans(skb, rx_ring->netdev);
> }
>
> +static inline unsigned int igb_rx_offset(struct igb_ring *rx_ring)
Likewise.
I know this function is just being moved, but nevertheless the inline tag should
be removed.
Thanks.
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