On Sat, Mar 21, 2020 at 3:04 AM Daniel T. Lee <danieltimlee@xxxxxxxxx> wrote:
>
> 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. Also, bpf_link__destroy manages the close() of
> perf_event fd.
>
> This commit refactors samples that attach the bpf program to perf_event
> by using libbbpf instead of ioctl. Also the bpf_load in the samples were
> removed and migrated to use libbbpf API.
>
> Signed-off-by: Daniel T. Lee <danieltimlee@xxxxxxxxx>
>
> ---
LGTM.
Acked-by: Andrii Nakryiko <andriin@xxxxxx>
> 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
> - find program with name explicitly instead of bpf_program__next
> - unconditional bpf_link__destroy() on cleanup
>
> 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
>
> samples/bpf/Makefile | 4 +-
> samples/bpf/sampleip_user.c | 98 +++++++++++++++--------
> samples/bpf/trace_event_user.c | 139 ++++++++++++++++++++++-----------
> 3 files changed, 159 insertions(+), 82 deletions(-)
>
[...]
