Hi Yonghong, Really sorry for the long delay. Now I am restarting this work.
On Mon, Dec 16, 2024 at 09:21:15AM -0800, Yonghong Song wrote: > On 12/15/24 11:34 AM, Leo Yan wrote: > > The bpf_perf_event_aux_pause kfunc will be used to control the Perf AUX > > area to pause or resume. > > > > An example use-case is attaching eBPF to Ftrace tracepoints. When a > > tracepoint is hit, the associated eBPF program will be executed. The > > eBPF program can invoke bpf_perf_event_aux_pause() to pause or resume > > AUX trace. This is useful for fine-grained tracing by combining > > Perf and eBPF. > > > > This commit implements the bpf_perf_event_aux_pause kfunc, and make it > > pass the eBPF verifier. > > The subject and commit message mentions to implement a kfunc, > but actually you implemented a uapi helper. Please implement a kfunc > instead (searching __bpf_kfunc in kernel/bpf directory). After some research, my understanding is that kfunc is flexible for exposing APIs via BTF, whereas BPF_CALL is typically used for core BPF features - such as accessing BPF maps. Coming back to this patch: it exposes a function with the following definition: int bpf_perf_event_aux_pause(struct bpf_map *map, u64 flags, u32 pause); I'm not certain whether using __bpf_kfunc is appropriate here, or if I should stick to BPF_CALL to ensure support for accessing bpf_map pointers? Thanks, Leo
