[bpf-next,0/6] AF_XDP Packet Drop Tracing

Message

Ciara Loftus Jan. 25, 2021, 9:07 a.m. UTC

This series introduces tracing infrastructure for AF_XDP sockets (xsks).
A trace event 'xsk_packet_drop' is created which can be enabled by toggling

/sys/kernel/debug/tracing/events/xsk/xsk_packet_drop/enable

When enabled and packets are dropped in the kernel, traces are generated
which describe the reason for the packet drop as well as the netdev and
qid information of the xsk which encountered the drop.

Example traces:

507.588563: xsk_packet_drop: netdev: eth0 qid 0 reason: rxq full
507.588567: xsk_packet_drop: netdev: eth0 qid 0 reason: packet too big
507.588568: xsk_packet_drop: netdev: eth0 qid 0 reason: fq empty

The event can also be monitored using perf:

perf stat -a -e xsk:xsk_packet_drop

Three selftests are added which each ensure the appropriate traces are
generated for the following scenarios:
* rx queue full
* packet too big
* fill queue empty

Ciara Loftus (6):
  xsk: add tracepoints for packet drops
  selftests/bpf: restructure setting the packet count
  selftests/bpf: add framework for xsk selftests
  selftests/bpf: XSK_TRACE_DROP_RXQ_FULL test
  selftests/bpf: XSK_TRACE_DROP_PKT_TOO_BIG test
  selftests/bpf: XSK_TRACE_DROP_FQ_EMPTY test

 MAINTAINERS                                |   1 +
 include/linux/bpf_trace.h                  |   1 +
 include/trace/events/xsk.h                 |  45 +++++
 include/uapi/linux/if_xdp.h                |   8 +
 kernel/bpf/core.c                          |   1 +
 net/xdp/xsk.c                              |   5 +
 net/xdp/xsk_buff_pool.c                    |   8 +-
 tools/include/uapi/linux/if_xdp.h          |   8 +
 tools/testing/selftests/bpf/test_xsk.sh    |  90 +++++++++-
 tools/testing/selftests/bpf/xdpxceiver.c   | 186 +++++++++++++++++++--
 tools/testing/selftests/bpf/xdpxceiver.h   |  10 ++
 tools/testing/selftests/bpf/xsk_prereqs.sh |   3 +-
 12 files changed, 344 insertions(+), 22 deletions(-)
 create mode 100644 include/trace/events/xsk.h