From: Jesper Dangaard Brouer <brouer@redhat.com>
To: sameehj@amazon.com
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org, zorik@amazon.com,
akiyano@amazon.com, gtzalik@amazon.com,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Daniel Borkmann" <borkmann@iogearbox.net>,
"Alexei Starovoitov" <alexei.starovoitov@gmail.com>,
"John Fastabend" <john.fastabend@gmail.com>,
"Alexander Duyck" <alexander.duyck@gmail.com>,
"Jeff Kirsher" <jeffrey.t.kirsher@intel.com>,
"David Ahern" <dsahern@gmail.com>,
"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Lorenzo Bianconi" <lorenzo@kernel.org>,
"Saeed Mahameed" <saeedm@mellanox.com>,
steffen.klassert@secunet.com
Subject: [PATCH net-next v2 08/33] xdp: cpumap redirect use frame_sz and increase skb_tailroom
Date: Thu, 30 Apr 2020 13:21:02 +0200 [thread overview]
Message-ID: <158824566208.2172139.12480344277742138090.stgit@firesoul> (raw)
In-Reply-To: <158824557985.2172139.4173570969543904434.stgit@firesoul>
Knowing the memory size backing the packet/xdp_frame data area, and
knowing it already have reserved room for skb_shared_info, simplifies
using build_skb significantly.
With this change we no-longer lie about the SKB truesize, but more
importantly a significant larger skb_tailroom is now provided, e.g. when
drivers uses a full PAGE_SIZE. This extra tailroom (in linear area) can be
used by the network stack when coalescing SKBs (e.g. in skb_try_coalesce,
see TCP cases where tcp_queue_rcv() can 'eat' skb).
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
kernel/bpf/cpumap.c | 21 +++------------------
1 file changed, 3 insertions(+), 18 deletions(-)
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index 3fe0b006d2d2..a71790dab12d 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -162,25 +162,10 @@ static struct sk_buff *cpu_map_build_skb(struct bpf_cpu_map_entry *rcpu,
/* Part of headroom was reserved to xdpf */
hard_start_headroom = sizeof(struct xdp_frame) + xdpf->headroom;
- /* build_skb need to place skb_shared_info after SKB end, and
- * also want to know the memory "truesize". Thus, need to
- * know the memory frame size backing xdp_buff.
- *
- * XDP was designed to have PAGE_SIZE frames, but this
- * assumption is not longer true with ixgbe and i40e. It
- * would be preferred to set frame_size to 2048 or 4096
- * depending on the driver.
- * frame_size = 2048;
- * frame_len = frame_size - sizeof(*xdp_frame);
- *
- * Instead, with info avail, skb_shared_info in placed after
- * packet len. This, unfortunately fakes the truesize.
- * Another disadvantage of this approach, the skb_shared_info
- * is not at a fixed memory location, with mixed length
- * packets, which is bad for cache-line hotness.
+ /* Memory size backing xdp_frame data already have reserved
+ * room for build_skb to place skb_shared_info in tailroom.
*/
- frame_size = SKB_DATA_ALIGN(xdpf->len + hard_start_headroom) +
- SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+ frame_size = xdpf->frame_sz;
pkt_data_start = xdpf->data - hard_start_headroom;
skb = build_skb_around(skb, pkt_data_start, frame_size);
next prev parent reply other threads:[~2020-04-30 11:21 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <158824557985.2172139.4173570969543904434.stgit@firesoul>
2020-04-30 11:20 ` [PATCH net-next v2 01/33] xdp: add frame size to xdp_buff Jesper Dangaard Brouer
2020-04-30 11:20 ` [PATCH net-next v2 02/33] bnxt: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-30 11:20 ` [PATCH net-next v2 03/33] sfc: add XDP frame size Jesper Dangaard Brouer
2020-04-30 11:20 ` [PATCH net-next v2 04/33] mvneta: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-30 11:20 ` [PATCH net-next v2 05/33] net: netsec: Add support for XDP frame size Jesper Dangaard Brouer
2020-04-30 11:20 ` [PATCH net-next v2 06/33] net: XDP-generic determining " Jesper Dangaard Brouer
2020-04-30 11:20 ` [PATCH net-next v2 07/33] xdp: xdp_frame add member frame_sz and handle in convert_to_xdp_frame Jesper Dangaard Brouer
2020-04-30 11:21 ` Jesper Dangaard Brouer [this message]
2020-04-30 11:21 ` [PATCH net-next v2 09/33] veth: adjust hard_start offset on redirect XDP frames Jesper Dangaard Brouer
2020-04-30 11:21 ` [PATCH net-next v2 10/33] veth: xdp using frame_sz in veth driver Jesper Dangaard Brouer
2020-04-30 11:21 ` [PATCH net-next v2 11/33] dpaa2-eth: add XDP frame size Jesper Dangaard Brouer
2020-04-30 11:21 ` [PATCH net-next v2 12/33] hv_netvsc: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-30 14:20 ` Haiyang Zhang
2020-05-01 14:47 ` Jesper Dangaard Brouer
2020-04-30 11:21 ` [PATCH net-next v2 13/33] qlogic/qede: " Jesper Dangaard Brouer
2020-04-30 11:21 ` [PATCH net-next v2 14/33] net: ethernet: ti: add XDP frame size to driver cpsw Jesper Dangaard Brouer
2020-04-30 11:21 ` [PATCH net-next v2 15/33] ena: add XDP frame size to amazon NIC driver Jesper Dangaard Brouer
2020-04-30 11:21 ` [PATCH net-next v2 16/33] mlx4: add XDP frame size and adjust max XDP MTU Jesper Dangaard Brouer
2020-04-30 11:21 ` [PATCH net-next v2 17/33] net: thunderx: add XDP frame size Jesper Dangaard Brouer
2020-04-30 11:21 ` [PATCH net-next v2 18/33] nfp: add XDP frame size to netronome driver Jesper Dangaard Brouer
2020-04-30 11:21 ` [PATCH net-next v2 19/33] tun: add XDP frame size Jesper Dangaard Brouer
2020-05-06 20:32 ` Michael S. Tsirkin
2020-04-30 11:22 ` [PATCH net-next v2 20/33] vhost_net: also populate " Jesper Dangaard Brouer
2020-05-06 6:41 ` Jason Wang
2020-05-06 6:49 ` Jason Wang
2020-05-06 20:33 ` Michael S. Tsirkin
2020-04-30 11:22 ` [PATCH net-next v2 21/33] virtio_net: add XDP frame size in two code paths Jesper Dangaard Brouer
2020-05-06 20:34 ` Michael S. Tsirkin
2020-05-08 2:05 ` Jason Wang
2020-05-08 7:21 ` Jesper Dangaard Brouer
2020-04-30 11:22 ` [PATCH net-next v2 22/33] ixgbe: fix XDP redirect on archs with PAGE_SIZE above 4K Jesper Dangaard Brouer
2020-04-30 11:22 ` [PATCH net-next v2 23/33] ixgbe: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-30 11:22 ` [PATCH net-next v2 24/33] ixgbevf: add XDP frame size to VF driver Jesper Dangaard Brouer
2020-04-30 11:22 ` [PATCH net-next v2 25/33] i40e: add XDP frame size to driver Jesper Dangaard Brouer
2020-04-30 11:22 ` [PATCH net-next v2 26/33] ice: " Jesper Dangaard Brouer
2020-04-30 11:22 ` [PATCH net-next v2 27/33] xdp: for Intel AF_XDP drivers add XDP frame_sz Jesper Dangaard Brouer
2020-04-30 11:22 ` [PATCH net-next v2 28/33] mlx5: rx queue setup time determine frame_sz for XDP Jesper Dangaard Brouer
2020-04-30 17:07 ` Tariq Toukan
2020-04-30 17:12 ` Tariq Toukan
2020-05-01 12:32 ` Jesper Dangaard Brouer
2020-05-08 10:49 ` Jesper Dangaard Brouer
2020-05-01 13:01 ` Jesper Dangaard Brouer
2020-04-30 11:22 ` [PATCH net-next v2 29/33] xdp: allow bpf_xdp_adjust_tail() to grow packet size Jesper Dangaard Brouer
2020-04-30 11:22 ` [PATCH net-next v2 30/33] xdp: clear grow memory in bpf_xdp_adjust_tail() Jesper Dangaard Brouer
2020-04-30 11:22 ` [PATCH net-next v2 31/33] bpf: add xdp.frame_sz in bpf_prog_test_run_xdp() Jesper Dangaard Brouer
2020-04-30 11:23 ` [PATCH net-next v2 32/33] selftests/bpf: adjust BPF selftest for xdp_adjust_tail Jesper Dangaard Brouer
2020-04-30 11:23 ` [PATCH net-next v2 33/33] selftests/bpf: xdp_adjust_tail add grow tail tests Jesper Dangaard Brouer
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