On Fri, Feb 05, 2021 at 07:35:22PM +0900, Namhyung Kim wrote: > Hello, > > On Fri, Feb 5, 2021 at 3:50 PM Yang Jihong <yangjiho...@huawei.com> wrote: > > > > commit da231338ec9c098707c8a1e4d8a50e2400e2fe17 uses eventfd to solve rare > > race > > where the setting and checking of 'done' which add done_fd to pollfd. > > When draining buffer, revents of done_fd is 0 and evlist__filter_pollfd > > function returns a non-zero value. > > As a result, perf record does not stop profiling. > > > > The following simple scenarios can trigger this condition: > > > > sleep 10 & > > perf record -p $! > > > > After the sleep process exits, perf record should stop profiling and exit. > > However, perf record keeps running. > > > > If pollfd revents contains only POLLERR or POLLHUP, > > perf record indicates that buffer is draining and need to stop profiling. > > Use fdarray_flag__nonfilterable to set done eventfd to nonfilterable > > objects, > > so that evlist__filter_pollfd does not filter and check done eventfd. > > > > Fixes: da231338ec9c (perf record: Use an eventfd to wakeup when done) > > Signed-off-by: Yang Jihong <yangjiho...@huawei.com> > > --- > > tools/perf/builtin-record.c | 2 +- > > tools/perf/util/evlist.c | 8 ++++++++ > > tools/perf/util/evlist.h | 4 ++++ > > 3 files changed, 13 insertions(+), 1 deletion(-) > > > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > > index fd3911650612..51e593e896ea 100644 > > --- a/tools/perf/builtin-record.c > > +++ b/tools/perf/builtin-record.c > > @@ -1663,7 +1663,7 @@ static int __cmd_record(struct record *rec, int argc, > > const char **argv) > > status = -1; > > goto out_delete_session; > > } > > - err = evlist__add_pollfd(rec->evlist, done_fd); > > + err = evlist__add_wakeup_eventfd(rec->evlist, done_fd); > > if (err < 0) { > > pr_err("Failed to add wakeup eventfd to poll list\n"); > > status = err; > > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c > > index 05363a7247c4..fea4c1e8010d 100644 > > --- a/tools/perf/util/evlist.c > > +++ b/tools/perf/util/evlist.c > > @@ -572,6 +572,14 @@ int evlist__filter_pollfd(struct evlist *evlist, short > > revents_and_mask) > > return perf_evlist__filter_pollfd(&evlist->core, revents_and_mask); > > } > > > > +#ifdef HAVE_EVENTFD_SUPPORT > > +int evlist__add_wakeup_eventfd(struct evlist *evlist, int fd) > > +{ > > + return perf_evlist__add_pollfd(&evlist->core, fd, NULL, POLLIN, > > + fdarray_flag__nonfilterable); > > +} > > +#endif > > Does it build when HAVE_EVENTFD_SUPPORT is not defined?
yea, I was wondering the same.. but it's called only from code within HAVE_EVENTFD_SUPPORT ifdef jirka > > Thanks, > Namhyung > > > > + > > int evlist__poll(struct evlist *evlist, int timeout) > > { > > return perf_evlist__poll(&evlist->core, timeout); > > diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h > > index 1aae75895dea..6d4d62151bc8 100644 > > --- a/tools/perf/util/evlist.h > > +++ b/tools/perf/util/evlist.h > > @@ -142,6 +142,10 @@ struct evsel *evlist__find_tracepoint_by_name(struct > > evlist *evlist, const char > > int evlist__add_pollfd(struct evlist *evlist, int fd); > > int evlist__filter_pollfd(struct evlist *evlist, short revents_and_mask); > > > > +#ifdef HAVE_EVENTFD_SUPPORT > > +int evlist__add_wakeup_eventfd(struct evlist *evlist, int fd); > > +#endif > > + > > int evlist__poll(struct evlist *evlist, int timeout); > > > > struct evsel *evlist__id2evsel(struct evlist *evlist, u64 id); > > -- > > 2.17.1 > > >