[PATCH v3 bpf-next 08/10] selftests/bpf: extend the storage test to test per-cpu cgroup storage

From: Roman Gushchin
Date: Wed Sep 26 2018 - 07:34:28 EST


This test extends the cgroup storage test to use per-cpu flavor
of the cgroup storage as well.

The test initializes a per-cpu cgroup storage to some non-zero initial
value (1000), and then simple bumps a per-cpu counter each time
the shared counter is atomically incremented. Then it reads all
per-cpu areas from the userspace side, and checks that the sum
of values adds to the expected sum.

Expected output:
$ ./test_cgroup_storage
test_cgroup_storage:PASS

Signed-off-by: Roman Gushchin <guro@xxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
---
.../selftests/bpf/test_cgroup_storage.c | 60 ++++++++++++++++++-
1 file changed, 57 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_cgroup_storage.c b/tools/testing/selftests/bpf/test_cgroup_storage.c
index 4e196e3bfecf..f44834155f25 100644
--- a/tools/testing/selftests/bpf/test_cgroup_storage.c
+++ b/tools/testing/selftests/bpf/test_cgroup_storage.c
@@ -4,6 +4,7 @@
#include <linux/filter.h>
#include <stdio.h>
#include <stdlib.h>
+#include <sys/sysinfo.h>

#include "bpf_rlimit.h"
#include "cgroup_helpers.h"
@@ -15,6 +16,14 @@ char bpf_log_buf[BPF_LOG_BUF_SIZE];
int main(int argc, char **argv)
{
struct bpf_insn prog[] = {
+ BPF_LD_MAP_FD(BPF_REG_1, 0), /* percpu map fd */
+ BPF_MOV64_IMM(BPF_REG_2, 0), /* flags, not used */
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+ BPF_FUNC_get_local_storage),
+ BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_0, 0),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 0x1),
+ BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_3, 0),
+
BPF_LD_MAP_FD(BPF_REG_1, 0), /* map fd */
BPF_MOV64_IMM(BPF_REG_2, 0), /* flags, not used */
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
@@ -28,9 +37,18 @@ int main(int argc, char **argv)
};
size_t insns_cnt = sizeof(prog) / sizeof(struct bpf_insn);
int error = EXIT_FAILURE;
- int map_fd, prog_fd, cgroup_fd;
+ int map_fd, percpu_map_fd, prog_fd, cgroup_fd;
struct bpf_cgroup_storage_key key;
unsigned long long value;
+ unsigned long long *percpu_value;
+ int cpu, nproc;
+
+ nproc = get_nprocs_conf();
+ percpu_value = malloc(sizeof(*percpu_value) * nproc);
+ if (!percpu_value) {
+ printf("Not enough memory for per-cpu area (%d cpus)\n", nproc);
+ goto err;
+ }

map_fd = bpf_create_map(BPF_MAP_TYPE_CGROUP_STORAGE, sizeof(key),
sizeof(value), 0, 0);
@@ -39,7 +57,15 @@ int main(int argc, char **argv)
goto out;
}

- prog[0].imm = map_fd;
+ percpu_map_fd = bpf_create_map(BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
+ sizeof(key), sizeof(value), 0, 0);
+ if (percpu_map_fd < 0) {
+ printf("Failed to create map: %s\n", strerror(errno));
+ goto out;
+ }
+
+ prog[0].imm = percpu_map_fd;
+ prog[7].imm = map_fd;
prog_fd = bpf_load_program(BPF_PROG_TYPE_CGROUP_SKB,
prog, insns_cnt, "GPL", 0,
bpf_log_buf, BPF_LOG_BUF_SIZE);
@@ -77,7 +103,15 @@ int main(int argc, char **argv)
}

if (bpf_map_lookup_elem(map_fd, &key, &value)) {
- printf("Failed to lookup cgroup storage\n");
+ printf("Failed to lookup cgroup storage 0\n");
+ goto err;
+ }
+
+ for (cpu = 0; cpu < nproc; cpu++)
+ percpu_value[cpu] = 1000;
+
+ if (bpf_map_update_elem(percpu_map_fd, &key, percpu_value, 0)) {
+ printf("Failed to update the data in the cgroup storage\n");
goto err;
}

@@ -120,11 +154,31 @@ int main(int argc, char **argv)
goto err;
}

+ /* Check the final value of the counter in the percpu local storage */
+
+ for (cpu = 0; cpu < nproc; cpu++)
+ percpu_value[cpu] = 0;
+
+ if (bpf_map_lookup_elem(percpu_map_fd, &key, percpu_value)) {
+ printf("Failed to lookup the per-cpu cgroup storage\n");
+ goto err;
+ }
+
+ value = 0;
+ for (cpu = 0; cpu < nproc; cpu++)
+ value += percpu_value[cpu];
+
+ if (value != nproc * 1000 + 6) {
+ printf("Unexpected data in the per-cpu cgroup storage\n");
+ goto err;
+ }
+
error = 0;
printf("test_cgroup_storage:PASS\n");

err:
cleanup_cgroup_environment();
+ free(percpu_value);

out:
return error;
--
2.17.1