Currently, some samples are using ioctl for enabling perf_event and
attaching BPF programs to this event. However, the bpf_program__attach
of libbpf(using bpf_link) is much more intuitive than the previous
method using ioctl.
bpf_program__attach_perf_event manages the enable of perf_event and
attach of BPF programs to it, so there's no neeed to do this
directly with ioctl.
In addition, bpf_link provides consistency in the use of API because it
allows disable (detach, destroy) for multiple events to be treated as
one bpf_link__destroy.
To refactor samples with using this libbpf API, the bpf_load in the
samples were removed and migrated to libbbpf. Because read_trace_pipe
is used in bpf_load, multiple samples cannot be migrated to libbpf,
this function was moved to trace_helpers.
Changes in v2:
- check memory allocation is successful
- clean up allocated memory on error
Changes in v3:
- Improve pointer error check (IS_ERR())
- change to calloc for easier destroy of bpf_link
- remove perf_event fd list since bpf_link handles fd
- use newer bpf_object__{open/load} API instead of bpf_prog_load
- perf_event for _SC_NPROCESSORS_ONLN instead of _SC_NPROCESSORS_CONF
- sample specific chagnes...
Changes in v4:
- bpf_link *, bpf_object * set NULL on init & err for easier destroy
- close bpf object with bpf_object__close()
Changes in v5:
- on error, return error code with exit
Daniel T. Lee (2):
samples: bpf: move read_trace_pipe to trace_helpers
samples: bpf: refactor perf_event user program with libbpf bpf_link
samples/bpf/Makefile | 8 +-
samples/bpf/bpf_load.c | 20 ---
samples/bpf/bpf_load.h | 1 -
samples/bpf/sampleip_user.c | 98 +++++++++-----
samples/bpf/trace_event_user.c | 139 +++++++++++++-------
samples/bpf/tracex1_user.c | 1 +
samples/bpf/tracex5_user.c | 1 +
tools/testing/selftests/bpf/trace_helpers.c | 23 ++++
tools/testing/selftests/bpf/trace_helpers.h | 1 +
9 files changed, 187 insertions(+), 105 deletions(-)
--
2.25.1
