[PATCH 4/5] perf tools: Allow creation of cgroup without open

Namhyung Kim
2020-09-23T02:00:14Z

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>
---
tools/perf/builtin-stat.c | 2 +-
tools/perf/util/cgroup.c | 19 ++++++++++++-------
tools/perf/util/cgroup.h | 2 +-
3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 66a33d97192d..d9d5de6f3108 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2256,7 +2256,7 @@ 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 dcd18ef268a1..d82f4cad762c 100644
--- 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;
@@ -235,7 +240,7 @@ 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 eea6df8ee373..162906f3412a 100644
--- 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);

--
2.28.0.681.g6f77f65b4e-goog