Re: [External] Re: [PATCH bpf-next] selftests/bpf: fix some bugs in map_lookup_percpu_elem testcase

[Feng Zhou]

在 2022/5/17 上午11:09, Yonghong Song 写道:
> On 5/15/22 7:24 PM, Feng zhou wrote:
> > From: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>
> >
> > comments from Andrii Nakryiko, details in here:
> > https://lore.kernel.org/lkml/20220511093854.411-1-zhoufeng.zf@xxxxxxxxxxxxx/T/ 
> >
> >
> > 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@xxxxxxxxxxxxx>
>
> LGTM with a few nits below.
> Acked-by: Yonghong Song <yhs@xxxxxx>
Ok, will do. Thanks.

> > ---
> >   .../bpf/prog_tests/map_lookup_percpu_elem.c   | 49 +++++++++------
> >   .../bpf/progs/test_map_lookup_percpu_elem.c   | 61 ++++++++++++-------
> >   2 files changed, 70 insertions(+), 40 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..89ca170f1c25 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 +1,39 @@
> > -// SPDX-License-Identifier: GPL-2.0
> > -// Copyright (c) 2022 Bytedance
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/* Copyright (c) 2022 Bytedance */
> >     #include <test_progs.h>
>
> The above empty line is unnecessary.
>
> >   #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 +46,14 @@ 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);
> >   }
> [...]
> > +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;
>
> Please add an empty line here.
>
> > +    value = bpf_map_lookup_percpu_elem(ctx->map, &key, index);
> > +    if (value)
> > +        ctx->sum += *value;
> > +    return 0;
> > +}
> > +
> [...]