From: Feng Zhou zhoufeng.zf@bytedance.com

comments from Andrii Nakryiko, details in here: https://lore.kernel.org/lkml/20220511093854.411-1-zhoufeng.zf@bytedance.com/...

use /* */ instead of // use libbpf_num_possible_cpus() instead of sysconf(_SC_NPROCESSORS_ONLN) use 8 bytes for value size fix memory leak use ASSERT_EQ instead of ASSERT_OK add bpf_loop to fetch values on each possible CPU

Fixes: ed7c13776e20c74486b0939a3c1de984c5efb6aa ("selftests/bpf: add test case for bpf_map_lookup_percpu_elem") Signed-off-by: Feng Zhou zhoufeng.zf@bytedance.com --- v1->v2: Addressed comments from Yonghong Song. - Adjust the code format more details can be seen from here: https://lore.kernel.org/lkml/80ab09cf-6072-a75a-082d-2721f6f907ef@fb.com/T/

.../bpf/prog_tests/map_lookup_percpu_elem.c | 50 +++++++++------ .../bpf/progs/test_map_lookup_percpu_elem.c | 62 ++++++++++++------- 2 files changed, 71 insertions(+), 41 deletions(-)

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 index 58b24c2112b0..f987c9278912 100644 --- a/tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c +++ b/tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c @@ -1,30 +1,38 @@ -// SPDX-License-Identifier: GPL-2.0 -// Copyright (c) 2022 Bytedance +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (c) 2022 Bytedance */

#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); - int *buf; + __u64 key = 0, sum; + int ret, i; + int nr_cpus = libbpf_num_possible_cpus(); + __u64 *buf;

- buf = (int *)malloc(nr_cpus*sizeof(int)); + buf = (__u64 *)malloc(nr_cpus*sizeof(__u64)); if (!ASSERT_OK_PTR(buf, "malloc")) return; - memset(buf, 0, nr_cpus*sizeof(int)); - 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; + for (i = 0; i < nr_cpus; i++) + buf[i] = i; + sum = (nr_cpus-1)*nr_cpus/2; + + skel = test_map_lookup_percpu_elem__open(); + if (!ASSERT_OK_PTR(skel, "test_map_lookup_percpu_elem__open")) + goto exit; + + skel->rodata->nr_cpus = nr_cpus; + + ret = test_map_lookup_percpu_elem__load(skel); + if (!ASSERT_OK(ret, "test_map_lookup_percpu_elem__load")) + goto cleanup; + ret = test_map_lookup_percpu_elem__attach(skel); - ASSERT_OK(ret, "test_map_lookup_percpu_elem__attach"); + if (!ASSERT_OK(ret, "test_map_lookup_percpu_elem__attach")) + goto cleanup;

ret = bpf_map_update_elem(bpf_map__fd(skel->maps.percpu_array_map), &key, buf, 0); ASSERT_OK(ret, "percpu_array_map update"); @@ -37,10 +45,14 @@ void test_map_lookup_percpu_elem(void)

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"); + test_map_lookup_percpu_elem__detach(skel); + + ASSERT_EQ(skel->bss->percpu_array_elem_sum, sum, "percpu_array lookup percpu elem"); + ASSERT_EQ(skel->bss->percpu_hash_elem_sum, sum, "percpu_hash lookup percpu elem"); + ASSERT_EQ(skel->bss->percpu_lru_hash_elem_sum, sum, "percpu_lru_hash lookup percpu elem");

+cleanup: test_map_lookup_percpu_elem__destroy(skel); +exit: + free(buf); } 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 index 5d4ef86cbf48..57e875d6e6e0 100644 --- a/tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c +++ b/tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c @@ -1,52 +1,70 @@ -// SPDX-License-Identifier: GPL-2.0 -// Copyright (c) 2022 Bytedance +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (c) 2022 Bytedance */

#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; +__u64 percpu_array_elem_sum = 0; +__u64 percpu_hash_elem_sum = 0; +__u64 percpu_lru_hash_elem_sum = 0; +const volatile int nr_cpus;

struct { __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY); __uint(max_entries, 1); __type(key, __u32); - __type(value, __u32); + __type(value, __u64); } percpu_array_map SEC(".maps");

struct { __uint(type, BPF_MAP_TYPE_PERCPU_HASH); __uint(max_entries, 1); - __type(key, __u32); - __type(value, __u32); + __type(key, __u64); + __type(value, __u64); } percpu_hash_map SEC(".maps");

struct { __uint(type, BPF_MAP_TYPE_LRU_PERCPU_HASH); __uint(max_entries, 1); - __type(key, __u32); - __type(value, __u32); + __type(key, __u64); + __type(value, __u64); } percpu_lru_hash_map SEC(".maps");

+struct read_percpu_elem_ctx { + void *map; + __u64 sum; +}; + +static int read_percpu_elem_callback(__u32 index, struct read_percpu_elem_ctx *ctx) +{ + __u64 key = 0; + __u64 *value; + + value = bpf_map_lookup_percpu_elem(ctx->map, &key, index); + if (value) + ctx->sum += *value; + return 0; +} + SEC("tp/syscalls/sys_enter_getuid") int sysenter_getuid(const void *ctx) { - __u32 key = 0; - __u32 cpu = 0; - __u32 *value; + struct read_percpu_elem_ctx map_ctx;

- value = bpf_map_lookup_percpu_elem(&percpu_array_map, &key, cpu); - if (value) - percpu_array_elem_val = *value; + map_ctx.map = &percpu_array_map; + map_ctx.sum = 0; + bpf_loop(nr_cpus, read_percpu_elem_callback, &map_ctx, 0); + percpu_array_elem_sum = map_ctx.sum;

- value = bpf_map_lookup_percpu_elem(&percpu_hash_map, &key, cpu); - if (value) - percpu_hash_elem_val = *value; + map_ctx.map = &percpu_hash_map; + map_ctx.sum = 0; + bpf_loop(nr_cpus, read_percpu_elem_callback, &map_ctx, 0); + percpu_hash_elem_sum = map_ctx.sum;

- value = bpf_map_lookup_percpu_elem(&percpu_lru_hash_map, &key, cpu); - if (value) - percpu_lru_hash_elem_val = *value; + map_ctx.map = &percpu_lru_hash_map; + map_ctx.sum = 0; + bpf_loop(nr_cpus, read_percpu_elem_callback, &map_ctx, 0); + percpu_lru_hash_elem_sum = map_ctx.sum;

return 0; }