RE: [RFC PATCH v2 4/7] libperf: Introduce perf_{evsel, evlist}__open_opt with extensible struct opts

[nakamura.shun@xxxxxxxxxxx]

Hi jirka

> On Fri, Mar 25, 2022 at 01:38:26PM +0900, Shunsuke Nakamura wrote:
> > Introduce perf_{evsel, evlist}__open_opt with extensible structure opts.
> > The mechanism of the extensible structure opts imitates
> > tools/lib/bpf/libbpf.h. This allows the user to set the open_flags
> > specified in perf_event_open and a signal handler to receive overflow
> > notifications for sampling events.
> >
> > Signed-off-by: Shunsuke Nakamura <nakamura.shun@xxxxxxxxxxx>
> > ---
> >  tools/lib/perf/Documentation/libperf.txt |  14 +++
> >  tools/lib/perf/evlist.c                  |  20 +++++
> >  tools/lib/perf/evsel.c                   | 105
> +++++++++++++++++++++++
> >  tools/lib/perf/include/perf/evlist.h     |   3 +
> >  tools/lib/perf/include/perf/evsel.h      |  26 ++++++
> >  tools/lib/perf/internal.h                |  44 ++++++++++
> >  tools/lib/perf/libperf.map               |   2 +
> >  7 files changed, 214 insertions(+)
> >
> > diff --git a/tools/lib/perf/Documentation/libperf.txt
> > b/tools/lib/perf/Documentation/libperf.txt
> > index ae55e62fc4ce..700c1ce15159 100644
> > --- a/tools/lib/perf/Documentation/libperf.txt
> > +++ b/tools/lib/perf/Documentation/libperf.txt
> > @@ -131,6 +131,20 @@ SYNOPSIS
> >            };
> >    };
> >
> > +  struct perf_evsel_open_opts {
> > +          /* size of this struct, for forward/backward compatibility */
> > +          size_t sz;
> > +
> > +          unsigned long open_flags;       /* perf_event_open flags */
> > +          int flags;                      /* fcntl flags */
> > +          unsigned int signal;
> > +          int owner_type;
> > +          struct sigaction *sig;
> > +  };
> > +  #define perf_evsel_open_opts__last_field sig
> > +
> > +  #define LIBPERF_OPTS(TYPE, NAME, ...)
> > +
> 
> SNIP
> 
> > +
> > +int perf_evsel__open_opts(struct perf_evsel *evsel, struct perf_cpu_map
> *cpus,
> > +			  struct perf_thread_map *threads,
> > +			  struct perf_evsel_open_opts *opts) {
> > +	int err = 0;
> > +
> > +	if (!OPTS_VALID(opts, perf_evsel_open_opts)) {
> > +		err = -EINVAL;
> > +		return err;
> > +	}
> > +
> > +	evsel->open_flags = OPTS_GET(opts, open_flags, 0);
> > +
> > +	err = perf_evsel__open(evsel, cpus, threads);
> > +	if (err)
> > +		return err;
> > +
> > +	err = perf_evsel__set_signal_handler(evsel, opts);
> > +	if (err)
> > +		return err;
> 
> please move the signal stuff handling into separate patch together with the
> related fields in opts struct
> 
I'll fix it.


Best Regards
Shunsuke