The control knobs set before loading BPF programs should be declared as
'const volatile' so that it can be optimized by the BPF core.
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/util/bpf_counter_cgroup.c | 6 +++---
tools/perf/util/bpf_skel/bperf_cgroup.bpf.c | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/bpf_counter_cgroup.c b/tools/perf/util/bpf_counter_cgroup.c
index ea29c372f339705d..6ff42619de12bddf 100644
--- a/tools/perf/util/bpf_counter_cgroup.c
+++ b/tools/perf/util/bpf_counter_cgroup.c
@@ -61,6 +61,9 @@ static int bperf_load_program(struct evlist *evlist)
skel->rodata->num_cpus = total_cpus;
skel->rodata->num_events = evlist->core.nr_entries / nr_cgroups;
+ if (cgroup_is_v2("perf_event") > 0)
+ skel->rodata->use_cgroup_v2 = 1;
+
BUG_ON(evlist->core.nr_entries % nr_cgroups != 0);
/* we need one copy of events per cpu for reading */
@@ -82,9 +85,6 @@ static int bperf_load_program(struct evlist *evlist)
goto out;
}
- if (cgroup_is_v2("perf_event") > 0)
- skel->bss->use_cgroup_v2 = 1;
-
err = -1;
cgrp_switch = evsel__new(&cgrp_switch_attr);
diff --git a/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c b/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
index 6a438e0102c5a2cb..57cab7647a9ad766 100644
--- a/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
+++ b/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
@@ -57,9 +57,9 @@ struct cgroup___old {
const volatile __u32 num_events = 1;
const volatile __u32 num_cpus = 1;
+const volatile int use_cgroup_v2 = 0;
int enabled = 0;
-int use_cgroup_v2 = 0;
int perf_subsys_id = -1;
static inline __u64 get_cgroup_v1_ancestor_id(struct cgroup *cgrp, int level)
--
2.46.0.469.g59c65b2a67-goog
