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kernel
os
linux
selftests/bpf: extend existing map resize tests for per-cpu use case
Add a per-cpu array resizing use case and demonstrate how
bpf_get_smp_processor_id() can be used to directly access proper data
with no extra checks.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230711232400.1658562-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
authored by
Andrii Nakryiko
and committed by
Alexei Starovoitov
c21de5fc
f42bcd16
+17
-5
+11
-3
tools/testing/selftests/bpf/prog_tests/global_map_resize.c
+11
-3
tools/testing/selftests/bpf/prog_tests/global_map_resize.c
···
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struct test_global_map_resize *skel;
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struct bpf_map *map;
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const __u32 desired_sz = sizeof(skel->bss->sum) + sysconf(_SC_PAGE_SIZE) * 2;
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-
size_t array_len, actual_sz;
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size_t array_len, actual_sz, new_sz;
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skel = test_global_map_resize__open();
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if (!ASSERT_OK_PTR(skel, "test_global_map_resize__open"))
···
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goto teardown;
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if (!ASSERT_EQ(bpf_map__value_size(map), desired_sz, "resize"))
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goto teardown;
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+
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new_sz = sizeof(skel->data_percpu_arr->percpu_arr[0]) * libbpf_num_possible_cpus();
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err = bpf_map__set_value_size(skel->maps.data_percpu_arr, new_sz);
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ASSERT_OK(err, "percpu_arr_resize");
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/* set the expected number of elements based on the resized array */
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array_len = (desired_sz - sizeof(skel->bss->sum)) / sizeof(skel->bss->array[0]);
···
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static void global_map_resize_data_subtest(void)
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{
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-
int err;
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struct test_global_map_resize *skel;
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struct bpf_map *map;
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const __u32 desired_sz = sysconf(_SC_PAGE_SIZE) * 2;
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size_t array_len, actual_sz;
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size_t array_len, actual_sz, new_sz;
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int err;
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skel = test_global_map_resize__open();
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if (!ASSERT_OK_PTR(skel, "test_global_map_resize__open"))
···
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goto teardown;
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if (!ASSERT_EQ(bpf_map__value_size(map), desired_sz, "resize"))
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goto teardown;
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new_sz = sizeof(skel->data_percpu_arr->percpu_arr[0]) * libbpf_num_possible_cpus();
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err = bpf_map__set_value_size(skel->maps.data_percpu_arr, new_sz);
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ASSERT_OK(err, "percpu_arr_resize");
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/* set the expected number of elements based on the resized array */
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array_len = (desired_sz - sizeof(skel->bss->sum)) / sizeof(skel->data_custom->my_array[0]);
+6
-2
tools/testing/selftests/bpf/progs/test_global_map_resize.c
+6
-2
tools/testing/selftests/bpf/progs/test_global_map_resize.c
···
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int my_array_first[1] SEC(".data.array_not_last");
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int my_int_last SEC(".data.array_not_last");
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int percpu_arr[1] SEC(".data.percpu_arr");
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+
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SEC("tp/syscalls/sys_enter_getpid")
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int bss_array_sum(void *ctx)
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{
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if (pid != (bpf_get_current_pid_tgid() >> 32))
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return 0;
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-
sum = 0;
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/* this will be zero, we just rely on verifier not rejecting this */
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sum = percpu_arr[bpf_get_smp_processor_id()];
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for (size_t i = 0; i < bss_array_len; ++i)
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sum += array[i];
···
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if (pid != (bpf_get_current_pid_tgid() >> 32))
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return 0;
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-
sum = 0;
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/* this will be zero, we just rely on verifier not rejecting this */
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sum = percpu_arr[bpf_get_smp_processor_id()];
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for (size_t i = 0; i < data_array_len; ++i)
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sum += my_array[i];