perf tools: Allow creation of cgroup without open

This is a preparation for a test case of expanding events for multiple
cgroups.  Instead of using real system cgroup, the test will use fake
cgroups so it needs a way to have them without a open file descriptor.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200924124455.336326-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 2751699..b01af17 100644 (file)
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2235,7 +2235,7 @@ int cmd_stat(int argc, const char **argv)
                }
 
                if (evlist__expand_cgroup(evsel_list, stat_config.cgroup_list,
-                                         &stat_config.metric_events) < 0)
+                                         &stat_config.metric_events, true) < 0)
                        goto out;
        }
 

diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
index 6e64c90..b81324a 100644 (file)
--- a/tools/perf/util/cgroup.c
+++ b/tools/perf/util/cgroup.c
@@ -51,7 +51,7 @@ static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str
        return NULL;
 }
 
-static struct cgroup *cgroup__new(const char *name)
+static struct cgroup *cgroup__new(const char *name, bool do_open)
 {
        struct cgroup *cgroup = zalloc(sizeof(*cgroup));
 
@@ -61,9 +61,14 @@ static struct cgroup *cgroup__new(const char *name)
                cgroup->name = strdup(name);
                if (!cgroup->name)
                        goto out_err;
-               cgroup->fd = open_cgroup(name);
-               if (cgroup->fd == -1)
-                       goto out_free_name;
+
+               if (do_open) {
+                       cgroup->fd = open_cgroup(name);
+                       if (cgroup->fd == -1)
+                               goto out_free_name;
+               } else {
+                       cgroup->fd = -1;
+               }
        }
 
        return cgroup;
@@ -79,7 +84,7 @@ struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
 {
        struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
 
-       return cgroup ?: cgroup__new(name);
+       return cgroup ?: cgroup__new(name, true);
 }
 
 static int add_cgroup(struct evlist *evlist, const char *str)
@@ -197,7 +202,7 @@ int parse_cgroups(const struct option *opt, const char *str,
 }
 
 int evlist__expand_cgroup(struct evlist *evlist, const char *str,
-                         struct rblist *metric_events)
+                         struct rblist *metric_events, bool open_cgroup)
 {
        struct evlist *orig_list, *tmp_list;
        struct evsel *pos, *evsel, *leader;
@@ -240,7 +245,7 @@ int evlist__expand_cgroup(struct evlist *evlist, const char *str,
                        if (!name)
                                goto out_err;
 
-                       cgrp = cgroup__new(name);
+                       cgrp = cgroup__new(name, open_cgroup);
                        free(name);
                        if (cgrp == NULL)
                                goto out_err;

diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h
index eea6df8..162906f 100644 (file)
--- a/tools/perf/util/cgroup.h
+++ b/tools/perf/util/cgroup.h
@@ -26,7 +26,7 @@ struct rblist;
 
 struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name);
 int evlist__expand_cgroup(struct evlist *evlist, const char *cgroups,
-                         struct rblist *metric_events);
+                         struct rblist *metric_events, bool open_cgroup);
 
 void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup);