Re: [PATCH v6 15/26] perf trace: Filter the target's tasks in BPF

[Arnaldo Carvalho de Melo]

On Mon, Sep 28, 2026 at 11:25:54AM -0700, Ian Rogers wrote:
> +static bool task_traced(void)
> +{
> +	u64 pid_tgid = bpf_get_current_pid_tgid();
> +	pid_t pid = uses_tgid ? pid_tgid >> 32 : (pid_t)pid_tgid;
> +	bool *traced;
> +
> +	if (!has_pids_to_trace)
> +		return true;
> +

I didn't look at the generated code, some optimization may well make the
bpf_get_current_pif_tgid() to be executed only if has_pids_to_trace is
!NULL, otherwise it would be better to move that to after the test.

I'm applying it anyway, just caught my attention while applying.

- Arnaldo

> +	traced = bpf_map_lookup_elem(&pids_to_trace, &pid);
> +	return traced && *traced;
> +}