Messages in this thread Patch in this message | | | Date | Mon, 25 Aug 2014 09:57:53 +0300 | From | Adrian Hunter <> | Subject | Re: [PATCH 01/10] perf evlist: Introduce perf_evlist__filter_pollfd method |
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On 08/22/2014 11:59 PM, Arnaldo Carvalho de Melo wrote: > From: Arnaldo Carvalho de Melo <acme@redhat.com> > > To remove all entries in evlist->pollfd[] that have revents matching at > least one of the bits in the specified mask. > > It'll adjust evlist->nr_fds to the number of unfiltered fds and will > return this value, as a convenience and to avoid requiring direct access > to internal state of perf_evlist objects. > > This will be used after polling the evlist fds so that we remove fds > that were closed by the kernel. > > Cc: Adrian Hunter <adrian.hunter@intel.com> > Cc: David Ahern <dsahern@gmail.com> > Cc: Don Zickus <dzickus@redhat.com> > Cc: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Jiri Olsa <jolsa@redhat.com> > Cc: Mike Galbraith <efault@gmx.de> > Cc: Namhyung Kim <namhyung@kernel.org> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Stephane Eranian <eranian@google.com> > Link: http://lkml.kernel.org/n/tip-ki3oqbfjg84si3f9amhyqvzb@git.kernel.org > Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> > --- > tools/perf/util/evlist.c | 16 ++++++++++++++++ > tools/perf/util/evlist.h | 2 ++ > 2 files changed, 18 insertions(+) > > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c > index a3e28b49128a..bd7896073d10 100644 > --- a/tools/perf/util/evlist.c > +++ b/tools/perf/util/evlist.c > @@ -428,6 +428,22 @@ void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd) > evlist->nr_fds++; > } > > +int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask) > +{ > + int fd = 0, nr_fds = 0; > + > + while (fd < evlist->nr_fds) {
A for loop is clearer e.g.
for (fd = 0; fd < evlist->nr_fds; fd++) {
> + if ((evlist->pollfd[fd].revents & revents_and_mask) == 0) > + ++nr_fds; > + > + if (++fd != nr_fds) > + evlist->pollfd[nr_fds] = evlist->pollfd[fd];
That looks like it will go off the end of the array. Shouldn't it be:
if ((evlist->pollfd[fd].revents & revents_and_mask) == 0) { if (fd != nr_fds) evlist->pollfd[nr_fds] = evlist->pollfd[fd]; nr_fds += 1; }
> + } > + > + evlist->nr_fds = nr_fds; > + return nr_fds; > +} > + > static void perf_evlist__id_hash(struct perf_evlist *evlist, > struct perf_evsel *evsel, > int cpu, int thread, u64 id) > diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h > index 106de53a6a74..1082420951f9 100644 > --- a/tools/perf/util/evlist.h > +++ b/tools/perf/util/evlist.h > @@ -84,6 +84,8 @@ void perf_evlist__id_add(struct perf_evlist *evlist, struct perf_evsel *evsel, > > void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd); > > +int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask); > + > struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id); > > struct perf_sample_id *perf_evlist__id2sid(struct perf_evlist *evlist, u64 id); >
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