在 2022/5/12 上午11:34, Andrii Nakryiko 写道:
On Wed, May 11, 2022 at 2:39 AM Feng zhou <zhoufeng.zf@xxxxxxxxxxxxx> wrote:
From: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>
test_progs:
Tests new ebpf helpers bpf_map_lookup_percpu_elem.
Signed-off-by: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>
---
.../bpf/prog_tests/map_lookup_percpu_elem.c | 46 ++++++++++++++++
.../bpf/progs/test_map_lookup_percpu_elem.c | 54 +++++++++++++++++++
2 files changed, 100 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c
create mode 100644 tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c
diff --git a/tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c b/tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c
new file mode 100644
index 000000000000..58b24c2112b0
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2022 Bytedance
/* */ instead of //
Ok, I will do. Thanks.
+
+#include <test_progs.h>
+
+#include "test_map_lookup_percpu_elem.skel.h"
+
+#define TEST_VALUE 1
+
+void test_map_lookup_percpu_elem(void)
+{
+ struct test_map_lookup_percpu_elem *skel;
+ int key = 0, ret;
+ int nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
I think this is actually wrong and will break selftests on systems
with offline CPUs. Please use libbpf_num_possible_cpus() instead.
Ok, I will do. Thanks.
+ int *buf;
+
+ buf = (int *)malloc(nr_cpus*sizeof(int));
+ if (!ASSERT_OK_PTR(buf, "malloc"))
+ return;
+ memset(buf, 0, nr_cpus*sizeof(int));
this is wrong, kernel expects to have roundup(sz, 8) per each CPU,
while you have just 4 bytes per each element
please also have spaces around multiplication operator here and above
Ok, I will use 8 bytes for key and val. Thanks.
+ buf[0] = TEST_VALUE;
+
+ skel = test_map_lookup_percpu_elem__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "test_map_lookup_percpu_elem__open_and_load"))
+ return;
buf leaking here
Yes, sorry for my negligence.
+ ret = test_map_lookup_percpu_elem__attach(skel);
+ ASSERT_OK(ret, "test_map_lookup_percpu_elem__attach");
+
+ ret = bpf_map_update_elem(bpf_map__fd(skel->maps.percpu_array_map), &key, buf, 0);
+ ASSERT_OK(ret, "percpu_array_map update");
+
+ ret = bpf_map_update_elem(bpf_map__fd(skel->maps.percpu_hash_map), &key, buf, 0);
+ ASSERT_OK(ret, "percpu_hash_map update");
+
+ ret = bpf_map_update_elem(bpf_map__fd(skel->maps.percpu_lru_hash_map), &key, buf, 0);
+ ASSERT_OK(ret, "percpu_lru_hash_map update");
+
+ syscall(__NR_getuid);
+
+ ret = skel->bss->percpu_array_elem_val == TEST_VALUE &&
+ skel->bss->percpu_hash_elem_val == TEST_VALUE &&
+ skel->bss->percpu_lru_hash_elem_val == TEST_VALUE;
+ ASSERT_OK(!ret, "bpf_map_lookup_percpu_elem success");
this would be better done as three separate ASSERT_EQ(), combining
into opaque true/false isn't helpful if something breaks
Good suggestion.
+
+ test_map_lookup_percpu_elem__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c b/tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c
new file mode 100644
index 000000000000..5d4ef86cbf48
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2022 Bytedance
/* */ instead of //
Ok, I will do. Thanks.
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+int percpu_array_elem_val = 0;
+int percpu_hash_elem_val = 0;
+int percpu_lru_hash_elem_val = 0;
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u32);
+} percpu_array_map SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u32);
+} percpu_hash_map SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_LRU_PERCPU_HASH);
+ __uint(max_entries, 1);
+ __type(key, __u32);
+ __type(value, __u32);
+} percpu_lru_hash_map SEC(".maps");
+
+SEC("tp/syscalls/sys_enter_getuid")
+int sysenter_getuid(const void *ctx)
+{
+ __u32 key = 0;
+ __u32 cpu = 0;
+ __u32 *value;
+
+ value = bpf_map_lookup_percpu_elem(&percpu_array_map, &key, cpu);
+ if (value)
+ percpu_array_elem_val = *value;
+
+ value = bpf_map_lookup_percpu_elem(&percpu_hash_map, &key, cpu);
+ if (value)
+ percpu_hash_elem_val = *value;
+
+ value = bpf_map_lookup_percpu_elem(&percpu_lru_hash_map, &key, cpu);
+ if (value)
+ percpu_lru_hash_elem_val = *value;
+
if the test happens to run on CPU 0 then the test doesn't really test
much. It would be more interesting to have a bpf_loop() iteration that
would fetch values on each possible CPU instead and do something with
it.
Good suggestion. I check the code and find no bpf helper function to get
possible CPU nums.
I think for the test function, read cpu0 elem value correctly should be
considered to be no problem.
Or is it necessary to add a new helper function to get num_possible_cpus ?
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.20.1
