On Tue, Sep 05, 2023 at 02:15:49PM +0800, Hou Tao wrote:
> Hi,
>
> On 8/28/2023 3:55 PM, Jiri Olsa wrote:
> > Adding support to gather stats for kprobe_multi programs.
> >
> > We now count:
> > - missed stats due to bpf_prog_active protection (always)
> > - cnt/nsec of the bpf program execution (if kernel.bpf_stats_enabled=1)
> >
> > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > ---
> > kernel/trace/bpf_trace.c | 8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> > index a7264b2c17ad..0a8685fc1eee 100644
> > --- a/kernel/trace/bpf_trace.c
> > +++ b/kernel/trace/bpf_trace.c
> > @@ -2706,18 +2706,24 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link,
> > .link = link,
> > .entry_ip = entry_ip,
> > };
> > + struct bpf_prog *prog = link->link.prog;
> > struct bpf_run_ctx *old_run_ctx;
> > + u64 start;
> > int err;
> >
> > if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
> > + bpf_prog_inc_misses_counter(prog);
> > err = 0;
> > goto out;
> > }
> >
> > +
> > migrate_disable();
> > rcu_read_lock();
> > old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
> > - err = bpf_prog_run(link->link.prog, regs);
> > + start = bpf_prog_start_time();
> > + err = bpf_prog_run(prog, regs);
> > + bpf_prog_update_prog_stats(prog, start);
>
> Oops, I missed the bpf_prog_run() here. It seems that bpf_prog_run() has
> already done the accounting thing, so there is no need for double
> accounting.
right, same as the other change, thanks
jirka
> > bpf_reset_run_ctx(old_run_ctx);
> > rcu_read_unlock();
> > migrate_enable();
>
