On Thu, Sep 01, 2016 at 10:12:51AM +0200, Peter Zijlstra wrote:
> On Wed, Aug 31, 2016 at 02:50:41PM -0700, Alexei Starovoitov wrote:
> > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> > index 97bfe62f30d7..dcaaaf3ec8e6 100644
> > --- a/include/linux/perf_event.h
> > +++ b/include/linux/perf_event.h
> > @@ -679,6 +679,8 @@ struct perf_event {
> > u64 (*clock)(void);
> > perf_overflow_handler_t overflow_handler;
> > void *overflow_handler_context;
>
> > + perf_overflow_handler_t orig_overflow_handler;
> > + struct bpf_prog *prog;
>
> Should we put that under CONFIG_BPF_SYSCALL too?
sure. will do.
> > diff --git a/kernel/events/core.c b/kernel/events/core.c
> > index 3cfabdf7b942..305433ab2447 100644
> > --- a/kernel/events/core.c
> > +++ b/kernel/events/core.c
>
> > @@ -7637,11 +7637,75 @@ static void perf_event_free_filter(struct
> > perf_event *event)
> > ftrace_profile_free_filter(event);
> > }
> >
> > +static void bpf_overflow_handler(struct perf_event *event,
> > + struct perf_sample_data *data,
> > + struct pt_regs *regs)
> > +{
> > + struct bpf_perf_event_data_kern ctx = {
> > + .data = data,
> > + .regs = regs,
> > + };
> > + int ret = 0;
> > +
> > +#ifdef CONFIG_BPF_SYSCALL
> > + preempt_disable();
> > + if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
> > + goto out;
> > + rcu_read_lock();
> > + ret = BPF_PROG_RUN(event->prog, (void *)&ctx);
> > + rcu_read_unlock();
> > + out:
>
> Please, no leading space before labels. Use something like:
good catch.
sadly checkpatch didn't complain.
> [diff "default"]
> xfuncname = "^[[:alpha:]$_].*[^:]$"
>
> In your .gitconfig if you want to keep diff output 'sane'.
interesting trick. don't remember being bitten by it.
This extra space was a typo.
> > + __this_cpu_dec(bpf_prog_active);
> > + preempt_enable();
> > +#endif
> > + if (!ret)
> > + return;
> > +
> > + event->orig_overflow_handler(event, data, regs);
> > +}
>
> Other than that, ACK.
Thanks!
