Messages in this thread | | | From | Ian Rogers <> | Date | Thu, 2 Mar 2023 17:40:30 -0800 | Subject | Re: [PATCH v2 05/10] perf evsel: Allow const evsel for certain accesses |
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On Thu, Mar 2, 2023 at 4:14 PM Namhyung Kim <namhyung@kernel.org> wrote: > > Hi Ian, > > On Thu, Mar 2, 2023 at 1:26 PM Ian Rogers <irogers@google.com> wrote: > > > > List sorting, added later to evlist, passes const elements requiring > > helper functions to also be const. Make the argument to > > evsel__find_pmu, evsel__is_aux_event and evsel__leader const. > > > > Signed-off-by: Ian Rogers <irogers@google.com> > > --- > > tools/perf/util/evsel.c | 2 +- > > tools/perf/util/evsel.h | 6 +++--- > > tools/perf/util/pmu.c | 6 +++--- > > tools/perf/util/python.c | 2 +- > > 4 files changed, 8 insertions(+), 8 deletions(-) > > > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c > > index 51e8ce6edddc..2dc2c24252bb 100644 > > --- a/tools/perf/util/evsel.c > > +++ b/tools/perf/util/evsel.c > > @@ -3139,7 +3139,7 @@ bool evsel__is_hybrid(const struct evsel *evsel) > > return evsel->pmu_name && perf_pmu__is_hybrid(evsel->pmu_name); > > } > > > > -struct evsel *evsel__leader(struct evsel *evsel) > > +struct evsel *evsel__leader(const struct evsel *evsel) > > It seems like it should return const struct evsel *, right?
Yes, but that breaks things :-)
> > { > > return container_of(evsel->core.leader, struct evsel, core); > > } > > diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h > > index 814a49ebb7e3..676c499323e9 100644 > > --- a/tools/perf/util/evsel.h > > +++ b/tools/perf/util/evsel.h > > @@ -212,8 +212,8 @@ int evsel__object_config(size_t object_size, > > int (*init)(struct evsel *evsel), > > void (*fini)(struct evsel *evsel)); > > > > -struct perf_pmu *evsel__find_pmu(struct evsel *evsel); > > -bool evsel__is_aux_event(struct evsel *evsel); > > +struct perf_pmu *evsel__find_pmu(const struct evsel *evsel); > > +bool evsel__is_aux_event(const struct evsel *evsel); > > > > struct evsel *evsel__new_idx(struct perf_event_attr *attr, int idx); > > > > @@ -505,7 +505,7 @@ int evsel__store_ids(struct evsel *evsel, struct evlist *evlist); > > > > void evsel__zero_per_pkg(struct evsel *evsel); > > bool evsel__is_hybrid(const struct evsel *evsel); > > -struct evsel *evsel__leader(struct evsel *evsel); > > +struct evsel *evsel__leader(const struct evsel *evsel); > > bool evsel__has_leader(struct evsel *evsel, struct evsel *leader); > > bool evsel__is_leader(struct evsel *evsel); > > void evsel__set_leader(struct evsel *evsel, struct evsel *leader); > > diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c > > index 43b6182d96b7..45d9b8e28e16 100644 > > --- a/tools/perf/util/pmu.c > > +++ b/tools/perf/util/pmu.c > > @@ -988,7 +988,7 @@ struct perf_pmu *perf_pmu__scan(struct perf_pmu *pmu) > > return NULL; > > } > > > > -struct perf_pmu *evsel__find_pmu(struct evsel *evsel) > > +struct perf_pmu *evsel__find_pmu(const struct evsel *evsel) > > { > > struct perf_pmu *pmu = NULL; > > > > @@ -1000,11 +1000,11 @@ struct perf_pmu *evsel__find_pmu(struct evsel *evsel) > > break; > > } > > > > - evsel->pmu = pmu; > > + ((struct evsel *)evsel)->pmu = pmu; > > Maybe we can move it out of the function and make callers set it.
Right, I considered this a case where in C++ we'd use mutable so casting away the const wasn't the worst offense.
Thanks, Ian
> Thanks, > Namhyung > > > > return pmu; > > } > > > > -bool evsel__is_aux_event(struct evsel *evsel) > > +bool evsel__is_aux_event(const struct evsel *evsel) > > { > > struct perf_pmu *pmu = evsel__find_pmu(evsel); > > > > diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c > > index 42e8b813d010..ab48ffbb6448 100644 > > --- a/tools/perf/util/python.c > > +++ b/tools/perf/util/python.c > > @@ -83,7 +83,7 @@ const char *perf_env__arch(struct perf_env *env __maybe_unused) > > * far, for the perf python binding known usecases, revisit if this become > > * necessary. > > */ > > -struct perf_pmu *evsel__find_pmu(struct evsel *evsel __maybe_unused) > > +struct perf_pmu *evsel__find_pmu(const struct evsel *evsel __maybe_unused) > > { > > return NULL; > > } > > -- > > 2.40.0.rc0.216.gc4246ad0f0-goog > >
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