[PATCH v4 bpf-next 0/4] libbpf: add perf buffer abstraction and API

[Andrii Nakryiko <andriin@fb.com>]

This patchset adds a high-level API for setting up and polling perf buffers
associated with BPF_MAP_TYPE_PERF_EVENT_ARRAY map. Details of APIs are
described in corresponding commit.

Patch #1 adds a set of APIs to set up and work with perf buffer.
Patch #2 enhances libbpf to support auto-setting PERF_EVENT_ARRAY map size.
Patch #3 adds test.
Patch #4 converts bpftool map event_pipe to new API.

v3->v4:
- fixed bpftool event_pipe cmd error handling (Jakub);

v2->v3:
- added perf_buffer__new_raw for more low-level control;
- converted bpftool map event_pipe to new API (Daniel);
- fixed bug with error handling in create_maps (Song);

v1->v2:
- add auto-sizing of PERF_EVENT_ARRAY maps;

Andrii Nakryiko (4):
  libbpf: add perf buffer API
  libbpf: auto-set PERF_EVENT_ARRAY size to number of CPUs
  selftests/bpf: test perf buffer API
  tools/bpftool: switch map event_pipe to libbpf's perf_buffer

 tools/bpf/bpftool/map_perf_ring.c             | 201 +++------
 tools/lib/bpf/libbpf.c                        | 397 +++++++++++++++++-
 tools/lib/bpf/libbpf.h                        |  49 +++
 tools/lib/bpf/libbpf.map                      |   4 +
 .../selftests/bpf/prog_tests/perf_buffer.c    |  94 +++++
 .../selftests/bpf/progs/test_perf_buffer.c    |  29 ++
 6 files changed, 630 insertions(+), 144 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_buffer.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_perf_buffer.c

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2.17.1