perf evlist: Introduce set_filter_pids method

We need to filter multiple pids in trace, i.e. trace itself,
gnome-terminal, X.org, etc.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-frtpkg7qapqwf7asa35wf8am@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evlist.c

@@ -1085,19 +1085,38 @@ int perf_evlist__set_filter(struct perf_evlist *evlist, const char *filter)
 	return err;
 }
 
-int perf_evlist__set_filter_pid(struct perf_evlist *evlist, pid_t pid)
+int perf_evlist__set_filter_pids(struct perf_evlist *evlist, size_t npids, pid_t *pids)
 {
 	char *filter;
-	int ret;
+	int ret = -1;
+	size_t i;
 
-	if (asprintf(&filter, "common_pid != %d", pid) < 0)
-		return -1;
+	for (i = 0; i < npids; ++i) {
+		if (i == 0) {
+			if (asprintf(&filter, "common_pid != %d", pids[i]) < 0)
+				return -1;
+		} else {
+			char *tmp;
+
+			if (asprintf(&tmp, "%s && common_pid != %d", filter, pids[i]) < 0)
+				goto out_free;
+
+			free(filter);
+			filter = tmp;
+		}
+	}
 
 	ret = perf_evlist__set_filter(evlist, filter);
+out_free:
 	free(filter);
 	return ret;
 }
 
+int perf_evlist__set_filter_pid(struct perf_evlist *evlist, pid_t pid)
+{
+	return perf_evlist__set_filter_pids(evlist, 1, &pid);
+}
+
 bool perf_evlist__valid_sample_type(struct perf_evlist *evlist)
 {
 	struct perf_evsel *pos;

tools/perf/util/evlist.h

@@ -78,6 +78,7 @@ int perf_evlist__add_newtp(struct perf_evlist *evlist,
 
 int perf_evlist__set_filter(struct perf_evlist *evlist, const char *filter);
 int perf_evlist__set_filter_pid(struct perf_evlist *evlist, pid_t pid);
+int perf_evlist__set_filter_pids(struct perf_evlist *evlist, size_t npids, pid_t *pids);
 
 struct perf_evsel *
 perf_evlist__find_tracepoint_by_id(struct perf_evlist *evlist, int id);