Re: [PATCH 2/8] perf bpf filter: Implement event sample filtering

Jiri Olsa
2023-02-21T11:54:58Z

On Sat, Feb 18, 2023 at 10:13:23PM -0800, Namhyung Kim wrote:

SNIP

> +#define FD(e, x, y) (*(int *)xyarray__entry(e->core.fd, x, y))
> +
> +int perf_bpf_filter__prepare(struct evsel *evsel)
> +{
> + int i, x, y, fd;
> + struct sample_filter_bpf *skel;
> + struct bpf_program *prog;
> + struct bpf_link *link;
> + struct perf_bpf_filter_expr *expr;
> +
> + skel = sample_filter_bpf__open();
> + if (!skel) {
> + pr_err("Failed to open perf sample-filter BPF skeleton\n");
> + return -1;
> + }
> +
> + bpf_map__set_max_entries(skel->maps.filters, MAX_FILTERS);

is this needed? max_entries is defined in the bpf object

jirka

> +
> + if (sample_filter_bpf__load(skel) < 0) {
> + pr_err("Failed to load perf sample-filter BPF skeleton\n");
> + return -1;
> + }
> +
> + i = 0;
> + fd = bpf_map__fd(skel->maps.filters);
> + list_for_each_entry(expr, &evsel->bpf_filters, list) {
> + struct perf_bpf_filter_entry entry = {
> + .op = expr->op,
> + .flags = expr->sample_flags,
> + .value = expr->val,
> + };
> + bpf_map_update_elem(fd, &i, &entry, BPF_ANY);
> + i++;
> + }
> +
> + prog = skel->progs.perf_sample_filter;
> + for (x = 0; x < xyarray__max_x(evsel->core.fd); x++) {
> + for (y = 0; y < xyarray__max_y(evsel->core.fd); y++) {
> + link = bpf_program__attach_perf_event(prog, FD(evsel, x, y));
> + if (IS_ERR(link)) {
> + pr_err("Failed to attach perf sample-filter program\n");
> + return PTR_ERR(link);
> + }
> + }
> + }
> + evsel->bpf_skel = skel;
> + return 0;
> +}
> +

SNIP