On Thu, Jul 7, 2022 at 12:14 AM Jon Doron <arilou@xxxxxxxxx> wrote:
Please prefix the patch with the target tree (bpf or bpf-next). For example,
this patch should go via bpf-next.
>
> From: Jon Doron <jond@xxxxxx>
>
> Add API for perfbuf to support writing a custom event reader.
This is too brief for such change. It is ok to duplicate text from the cover
letter.
Please also update libbpf.map.
Also, we should add a selftest to use these new APIs.
>
> Signed-off-by: Jon Doron <jond@xxxxxx>
> ---
> tools/lib/bpf/libbpf.c | 40 ++++++++++++++++++++++++++++++++++++++++
> tools/lib/bpf/libbpf.h | 6 ++++++
> 2 files changed, 46 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index e89cc9c885b3..37299aa05185 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -12433,6 +12433,46 @@ static int perf_buffer__process_records(struct perf_buffer *pb,
> return 0;
> }
>
> +int perf_buffer__raw_ring_buf(const struct perf_buffer *pb, size_t buf_idx,
> + void **base, size_t *buf_size, __u64 *head,
> + __u64 *tail)
Please add comments to each API function.
> +{
> + struct perf_cpu_buf *cpu_buf;
> + struct perf_event_mmap_page *header;
> +
> + if (buf_idx >= pb->cpu_cnt)
> + return libbpf_err(-EINVAL);
> +
> + cpu_buf = pb->cpu_bufs[buf_idx];
> + if (!cpu_buf)
> + return libbpf_err(-ENOENT);
> +
> + header = cpu_buf->base;
> + *head = ring_buffer_read_head(header);
> + *tail = header->data_tail;
> + *base = ((__u8 *)header) + pb->page_size;
> + *buf_size = pb->mmap_size;
> + return 0;
> +}
> +
> +int perf_buffer__set_ring_buf_tail(const struct perf_buffer *pb, size_t buf_idx,
> + __u64 tail)
> +{
> + struct perf_cpu_buf *cpu_buf;
> + struct perf_event_mmap_page *header;
> +
> + if (buf_idx >= pb->cpu_cnt)
> + return libbpf_err(-EINVAL);
> +
> + cpu_buf = pb->cpu_bufs[buf_idx];
> + if (!cpu_buf)
> + return libbpf_err(-ENOENT);
> +
> + header = cpu_buf->base;
> + ring_buffer_write_tail(header, tail);
> + return 0;
> +}
> +
> int perf_buffer__epoll_fd(const struct perf_buffer *pb)
> {
> return pb->epoll_fd;
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index 9e9a3fd3edd8..b6f6b6a12d70 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -1381,6 +1381,12 @@ LIBBPF_API int perf_buffer__consume(struct perf_buffer *pb);
> LIBBPF_API int perf_buffer__consume_buffer(struct perf_buffer *pb, size_t buf_idx);
> LIBBPF_API size_t perf_buffer__buffer_cnt(const struct perf_buffer *pb);
> LIBBPF_API int perf_buffer__buffer_fd(const struct perf_buffer *pb, size_t buf_idx);
> +LIBBPF_API int perf_buffer__raw_ring_buf(const struct perf_buffer *pb,
> + size_t buf_idx, void **base,
> + size_t *buf_size, __u64 *head,
> + __u64 *tail);
> +LIBBPF_API int perf_buffer__set_ring_buf_tail(const struct perf_buffer *pb,
> + size_t buf_idx, __u64 tail);
>
> typedef enum bpf_perf_event_ret
> (*bpf_perf_event_print_t)(struct perf_event_header *hdr,
> --
> 2.36.1
>
