[PATCH 11/28] perf trace: Fill in BPF "filtered_pids" map when present

Arnaldo Carvalho de Melo
2018-11-22T03:36:59Z

This makes the augmented_syscalls support the --filter-pids and
auto-filtered feedback loop pids just like when working without BPF,
i.e. with just raw_syscalls:sys_{enter,exit} and tracepoint filters.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-zc5n453sxxm0tz1zfwwelyti@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-trace.c | 61 ++++++++++++++++++++++++++++++++++++----------
1 file changed, 48 insertions(+), 13 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index c423a78b5ecd..8e3c3f74a3a4 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2567,9 +2567,27 @@ static int trace__set_ev_qualifier_filter(struct trace *trace)
goto out;
}

+static int bpf_map__set_filter_pids(struct bpf_map *map __maybe_unused,
+ size_t npids __maybe_unused, pid_t *pids __maybe_unused)
+{
+ int err = 0;
+#ifdef HAVE_LIBBPF_SUPPORT
+ bool value = true;
+ int map_fd = bpf_map__fd(map);
+ size_t i;
+
+ for (i = 0; i < npids; ++i) {
+ err = bpf_map_update_elem(map_fd, &pids[i], &value, BPF_ANY);
+ if (err)
+ break;
+ }
+#endif
+ return err;
+}
+
static int trace__set_filter_loop_pids(struct trace *trace)
{
- unsigned int nr = 1;
+ unsigned int nr = 1, err;
pid_t pids[32] = {
getpid(),
};
@@ -2588,7 +2606,34 @@ static int trace__set_filter_loop_pids(struct trace *trace)
thread = parent;
}

- return perf_evlist__set_tp_filter_pids(trace->evlist, nr, pids);
+ err = perf_evlist__set_tp_filter_pids(trace->evlist, nr, pids);
+ if (!err && trace->filter_pids.map)
+ err = bpf_map__set_filter_pids(trace->filter_pids.map, nr, pids);
+
+ return err;
+}
+
+static int trace__set_filter_pids(struct trace *trace)
+{
+ int err = 0;
+ /*
+ * Better not use !target__has_task() here because we need to cover the
+ * case where no threads were specified in the command line, but a
+ * workload was, and in that case we will fill in the thread_map when
+ * we fork the workload in perf_evlist__prepare_workload.
+ */
+ if (trace->filter_pids.nr > 0) {
+ err = perf_evlist__set_tp_filter_pids(trace->evlist, trace->filter_pids.nr,
+ trace->filter_pids.entries);
+ if (!err && trace->filter_pids.map) {
+ err = bpf_map__set_filter_pids(trace->filter_pids.map, trace->filter_pids.nr,
+ trace->filter_pids.entries);
+ }
+ } else if (thread_map__pid(trace->evlist->threads, 0) == -1) {
+ err = trace__set_filter_loop_pids(trace);
+ }
+
+ return err;
}

static int trace__run(struct trace *trace, int argc, const char **argv)
@@ -2697,17 +2742,7 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
goto out_error_open;
}

- /*
- * Better not use !target__has_task() here because we need to cover the
- * case where no threads were specified in the command line, but a
- * workload was, and in that case we will fill in the thread_map when
- * we fork the workload in perf_evlist__prepare_workload.
- */
- if (trace->filter_pids.nr > 0)
- err = perf_evlist__set_tp_filter_pids(evlist, trace->filter_pids.nr, trace->filter_pids.entries);
- else if (thread_map__pid(evlist->threads, 0) == -1)
- err = trace__set_filter_loop_pids(trace);
-
+ err = trace__set_filter_pids(trace);
if (err < 0)
goto out_error_mem;

--
2.14.5