[PATCHv2 RFC bpf-next 0/7] bpf: Add support for ftrace probe

[Jiri Olsa <jolsa@kernel.org>]

hi,
sending another attempt on speeding up load of multiple probes
for bpftrace and possibly other tools (first post in [1]).

This patchset adds support to attach bpf program directly to
ftrace probe as suggested by Steven and it speeds up loading
for bpftrace commands like:

   # bpftrace -e 'kfunc:_raw_spin* { @[probe] = count(); }'
   # bpftrace -e 'kfunc:ksys_* { @[probe] = count(); }'

Using ftrace with single bpf program for attachment to multiple
functions is much faster than current approach, where we need to
load and attach program for each probe function.

Also available in
  git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
  bpf/ftrace

thanks,
jirka


[1] https://lore.kernel.org/bpf/20201022082138.2322434-1-jolsa@kernel.org/
---
Jiri Olsa (7):
      bpf: Move bpf_prog_start/end functions to generic place
      bpf: Add bpf_functions object
      bpf: Add support to attach program to ftrace probe
      libbpf: Add btf__find_by_pattern_kind function
      libbpf: Add support to load and attach ftrace probe
      selftests/bpf: Add ftrace probe to fentry test
      selftests/bpf: Add ftrace probe test

 include/uapi/linux/bpf.h                             |   8 ++++
 kernel/bpf/syscall.c                                 | 381 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 kernel/bpf/trampoline.c                              |  97 ---------------------------------------
 kernel/bpf/verifier.c                                |  27 +++++++++++
 net/bpf/test_run.c                                   |   1 +
 tools/include/uapi/linux/bpf.h                       |   8 ++++
 tools/lib/bpf/bpf.c                                  |  12 +++++
 tools/lib/bpf/bpf.h                                  |   5 +-
 tools/lib/bpf/btf.c                                  |  67 +++++++++++++++++++++++++++
 tools/lib/bpf/btf.h                                  |   3 ++
 tools/lib/bpf/libbpf.c                               |  74 ++++++++++++++++++++++++++++++
 tools/lib/bpf/libbpf.map                             |   1 +
 tools/testing/selftests/bpf/prog_tests/fentry_test.c |   5 +-
 tools/testing/selftests/bpf/prog_tests/ftrace_test.c |  48 +++++++++++++++++++
 tools/testing/selftests/bpf/progs/fentry_test.c      |  16 +++++++
 tools/testing/selftests/bpf/progs/ftrace_test.c      |  17 +++++++
 16 files changed, 671 insertions(+), 99 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/ftrace_test.c
 create mode 100644 tools/testing/selftests/bpf/progs/ftrace_test.c