From: Lorenzo Bianconi <lorenzo@kernel.org>
To: bpf@vger.kernel.org, netdev@vger.kernel.org
Cc: lorenzo.bianconi@redhat.com, davem@davemloft.net,
kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net,
shayagr@amazon.com, john.fastabend@gmail.com, dsahern@kernel.org,
brouer@redhat.com, echaudro@redhat.com, jasowang@redhat.com,
alexander.duyck@gmail.com, saeed@kernel.org,
maciej.fijalkowski@intel.com, magnus.karlsson@intel.com,
tirthendu.sarkar@intel.com, toke@redhat.com
Subject: [PATCH v12 bpf-next 00/18] mvneta: introduce XDP multi-buffer support
Date: Fri, 20 Aug 2021 17:40:13 +0200 [thread overview]
Message-ID: <cover.1629473233.git.lorenzo@kernel.org> (raw)
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This series introduce XDP multi-buffer support. The mvneta driver is
the first to support these new "non-linear" xdp_{buff,frame}. Reviewers
please focus on how these new types of xdp_{buff,frame} packets
traverse the different layers and the layout design. It is on purpose
that BPF-helpers are kept simple, as we don't want to expose the
internal layout to allow later changes.
The main idea for the new multi-buffer layout is to reuse the same
structure used for non-linear SKB. This rely on the "skb_shared_info"
struct at the end of the first buffer to link together subsequent
buffers. Keeping the layout compatible with SKBs is also done to ease
and speedup creating a SKB from an xdp_{buff,frame}.
Converting xdp_frame to SKB and deliver it to the network stack is shown
in patch 05/18 (e.g. cpumaps).
A multi-buffer bit (mb) has been introduced in the flags field of xdp_{buff,frame}
structure to notify the bpf/network layer if this is a xdp multi-buffer frame
(mb = 1) or not (mb = 0).
The mb bit will be set by a xdp multi-buffer capable driver only for
non-linear frames maintaining the capability to receive linear frames
without any extra cost since the skb_shared_info structure at the end
of the first buffer will be initialized only if mb is set.
Moreover the flags field in xdp_{buff,frame} will be reused even for
xdp rx csum offloading in future series.
Typical use cases for this series are:
- Jumbo-frames
- Packet header split (please see Google’s use-case @ NetDevConf 0x14, [0])
- TSO/GRO
The two following ebpf helpers (and related selftests) has been introduced:
- bpf_xdp_adjust_data:
Move xdp_md->data and xdp_md->data_end pointers in subsequent fragments
according to the offset provided by the ebpf program. This helper can be
used to read/write values in frame payload.
- bpf_xdp_get_buff_len:
Return the total frame size (linear + paged parts)
bpf_xdp_adjust_tail and bpf_xdp_copy helpers have been modified to take into
account xdp multi-buff frames.
More info about the main idea behind this approach can be found here [1][2].
Changes since v11:
- add missing static to bpf_xdp_get_buff_len_proto structure
- fix bpf_xdp_adjust_data helper when offset is smaller than linear area length.
Changes since v10:
- move xdp->data to the requested payload offset instead of to the beginning of
the fragment in bpf_xdp_adjust_data()
Changes since v9:
- introduce bpf_xdp_adjust_data helper and related selftest
- add xdp_frags_size and xdp_frags_tsize fields in skb_shared_info
- introduce xdp_update_skb_shared_info utility routine in ordere to not reset
frags array in skb_shared_info converting from a xdp_buff/xdp_frame to a skb
- simplify bpf_xdp_copy routine
Changes since v8:
- add proper dma unmapping if XDP_TX fails on mvneta for a xdp multi-buff
- switch back to skb_shared_info implementation from previous xdp_shared_info
one
- avoid using a bietfield in xdp_buff/xdp_frame since it introduces performance
regressions. Tested now on 10G NIC (ixgbe) to verify there are no performance
penalties for regular codebase
- add bpf_xdp_get_buff_len helper and remove frame_length field in xdp ctx
- add data_len field in skb_shared_info struct
- introduce XDP_FLAGS_FRAGS_PF_MEMALLOC flag
Changes since v7:
- rebase on top of bpf-next
- fix sparse warnings
- improve comments for frame_length in include/net/xdp.h
Changes since v6:
- the main difference respect to previous versions is the new approach proposed
by Eelco to pass full length of the packet to eBPF layer in XDP context
- reintroduce multi-buff support to eBPF kself-tests
- reintroduce multi-buff support to bpf_xdp_adjust_tail helper
- introduce multi-buffer support to bpf_xdp_copy helper
- rebase on top of bpf-next
Changes since v5:
- rebase on top of bpf-next
- initialize mb bit in xdp_init_buff() and drop per-driver initialization
- drop xdp->mb initialization in xdp_convert_zc_to_xdp_frame()
- postpone introduction of frame_length field in XDP ctx to another series
- minor changes
Changes since v4:
- rebase ontop of bpf-next
- introduce xdp_shared_info to build xdp multi-buff instead of using the
skb_shared_info struct
- introduce frame_length in xdp ctx
- drop previous bpf helpers
- fix bpf_xdp_adjust_tail for xdp multi-buff
- introduce xdp multi-buff self-tests for bpf_xdp_adjust_tail
- fix xdp_return_frame_bulk for xdp multi-buff
Changes since v3:
- rebase ontop of bpf-next
- add patch 10/13 to copy back paged data from a xdp multi-buff frame to
userspace buffer for xdp multi-buff selftests
Changes since v2:
- add throughput measurements
- drop bpf_xdp_adjust_mb_header bpf helper
- introduce selftest for xdp multibuffer
- addressed comments on bpf_xdp_get_frags_count
- introduce xdp multi-buff support to cpumaps
Changes since v1:
- Fix use-after-free in xdp_return_{buff/frame}
- Introduce bpf helpers
- Introduce xdp_mb sample program
- access skb_shared_info->nr_frags only on the last fragment
Changes since RFC:
- squash multi-buffer bit initialization in a single patch
- add mvneta non-linear XDP buff support for tx side
[0] https://netdevconf.info/0x14/session.html?talk-the-path-to-tcp-4k-mtu-and-rx-zerocopy
[1] https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org
[2] https://netdevconf.info/0x14/session.html?tutorial-add-XDP-support-to-a-NIC-driver (XDPmulti-buffers section)
Eelco Chaudron (3):
bpf: add multi-buff support to the bpf_xdp_adjust_tail() API
bpf: add multi-buffer support to xdp copy helpers
bpf: update xdp_adjust_tail selftest to include multi-buffer
Lorenzo Bianconi (15):
net: skbuff: add size metadata to skb_shared_info for xdp
xdp: introduce flags field in xdp_buff/xdp_frame
net: mvneta: update mb bit before passing the xdp buffer to eBPF layer
net: mvneta: simplify mvneta_swbm_add_rx_fragment management
net: xdp: add xdp_update_skb_shared_info utility routine
net: marvell: rely on xdp_update_skb_shared_info utility routine
xdp: add multi-buff support to xdp_return_{buff/frame}
net: mvneta: add multi buffer support to XDP_TX
net: mvneta: enable jumbo frames for XDP
bpf: introduce bpf_xdp_get_buff_len helper
bpf: move user_size out of bpf_test_init
bpf: introduce multibuff support to bpf_prog_test_run_xdp()
bpf: test_run: add xdp_shared_info pointer in bpf_test_finish
signature
net: xdp: introduce bpf_xdp_adjust_data helper
bpf: add bpf_xdp_adjust_data selftest
drivers/net/ethernet/marvell/mvneta.c | 204 ++++++++++-------
include/linux/skbuff.h | 6 +-
include/net/xdp.h | 95 +++++++-
include/uapi/linux/bpf.h | 39 ++++
kernel/trace/bpf_trace.c | 3 +
net/bpf/test_run.c | 117 ++++++++--
net/core/filter.c | 213 +++++++++++++++++-
net/core/xdp.c | 76 ++++++-
tools/include/uapi/linux/bpf.h | 39 ++++
.../bpf/prog_tests/xdp_adjust_data.c | 55 +++++
.../bpf/prog_tests/xdp_adjust_tail.c | 118 ++++++++++
.../selftests/bpf/prog_tests/xdp_bpf2bpf.c | 151 +++++++++----
.../bpf/progs/test_xdp_adjust_tail_grow.c | 10 +-
.../bpf/progs/test_xdp_adjust_tail_shrink.c | 32 ++-
.../selftests/bpf/progs/test_xdp_bpf2bpf.c | 2 +-
.../bpf/progs/test_xdp_update_frags.c | 41 ++++
16 files changed, 1036 insertions(+), 165 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_adjust_data.c
create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_update_frags.c
--
2.31.1
next reply other threads:[~2021-08-20 15:41 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-20 15:40 Lorenzo Bianconi [this message]
2021-08-20 15:40 ` [PATCH v12 bpf-next 01/18] net: skbuff: add size metadata to skb_shared_info for xdp Lorenzo Bianconi
2021-08-31 23:13 ` John Fastabend
2021-09-03 17:13 ` Lorenzo Bianconi
2021-08-20 15:40 ` [PATCH v12 bpf-next 02/18] xdp: introduce flags field in xdp_buff/xdp_frame Lorenzo Bianconi
2021-08-31 23:15 ` John Fastabend
2021-08-20 15:40 ` [PATCH v12 bpf-next 03/18] net: mvneta: update mb bit before passing the xdp buffer to eBPF layer Lorenzo Bianconi
2021-08-31 23:23 ` John Fastabend
2021-09-03 17:23 ` Lorenzo Bianconi
2021-08-20 15:40 ` [PATCH v12 bpf-next 04/18] net: mvneta: simplify mvneta_swbm_add_rx_fragment management Lorenzo Bianconi
2021-08-31 23:34 ` John Fastabend
2021-08-20 15:40 ` [PATCH v12 bpf-next 05/18] net: xdp: add xdp_update_skb_shared_info utility routine Lorenzo Bianconi
2021-08-31 23:38 ` John Fastabend
2021-08-20 15:40 ` [PATCH v12 bpf-next 06/18] net: marvell: rely on " Lorenzo Bianconi
2021-08-31 23:41 ` John Fastabend
2021-09-03 17:27 ` Lorenzo Bianconi
2021-08-20 15:40 ` [PATCH v12 bpf-next 07/18] xdp: add multi-buff support to xdp_return_{buff/frame} Lorenzo Bianconi
2021-08-31 23:43 ` John Fastabend
2021-08-20 15:40 ` [PATCH v12 bpf-next 08/18] net: mvneta: add multi buffer support to XDP_TX Lorenzo Bianconi
2021-08-31 23:44 ` John Fastabend
2021-08-20 15:40 ` [PATCH v12 bpf-next 09/18] net: mvneta: enable jumbo frames for XDP Lorenzo Bianconi
2021-08-31 23:45 ` John Fastabend
2021-08-20 15:40 ` [PATCH v12 bpf-next 10/18] bpf: add multi-buff support to the bpf_xdp_adjust_tail() API Lorenzo Bianconi
2021-09-01 0:10 ` John Fastabend
2021-08-20 15:40 ` [PATCH v12 bpf-next 11/18] bpf: introduce bpf_xdp_get_buff_len helper Lorenzo Bianconi
2021-09-01 0:12 ` John Fastabend
2021-08-20 15:40 ` [PATCH v12 bpf-next 12/18] bpf: add multi-buffer support to xdp copy helpers Lorenzo Bianconi
2021-09-01 0:19 ` John Fastabend
2021-08-20 15:40 ` [PATCH v12 bpf-next 13/18] bpf: move user_size out of bpf_test_init Lorenzo Bianconi
2021-08-20 15:40 ` [PATCH v12 bpf-next 14/18] bpf: introduce multibuff support to bpf_prog_test_run_xdp() Lorenzo Bianconi
2021-08-20 15:40 ` [PATCH v12 bpf-next 15/18] bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature Lorenzo Bianconi
2021-08-20 15:40 ` [PATCH v12 bpf-next 16/18] bpf: update xdp_adjust_tail selftest to include multi-buffer Lorenzo Bianconi
2021-08-20 15:40 ` [PATCH v12 bpf-next 17/18] net: xdp: introduce bpf_xdp_adjust_data helper Lorenzo Bianconi
2021-09-01 0:36 ` John Fastabend
2021-09-03 17:57 ` Lorenzo Bianconi
2021-08-20 15:40 ` [PATCH v12 bpf-next 18/18] bpf: add bpf_xdp_adjust_data selftest Lorenzo Bianconi
2021-09-01 0:45 ` [PATCH v12 bpf-next 00/18] mvneta: introduce XDP multi-buffer support John Fastabend
2021-09-07 8:35 ` Lorenzo Bianconi
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