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| author | Hou Tao <houtao1@huawei.com> | 2023-11-01 06:24:55 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2023-11-10 05:58:40 +0300 |
| commit | 2f553b032cad4993969cab356b3b0e306fcd1cd1 (patch) | |
| tree | 989e0be5c06e56cf68317fbd3614ed9e2423d5b2 | |
| parent | b9b79553163788d3fc42e25c2662c0a46dc9a3c5 (diff) | |
| download | linux-2f553b032cad4993969cab356b3b0e306fcd1cd1.tar.xz | |
selftsets/bpf: Retry map update for non-preallocated per-cpu map
BPF CI failed due to map_percpu_stats_percpu_hash from time to time [1].
It seems that the failure reason is per-cpu bpf memory allocator may not
be able to allocate per-cpu pointer successfully and it can not refill
free llist timely, and bpf_map_update_elem() will return -ENOMEM.
So mitigate the problem by retrying the update operation for
non-preallocated per-cpu map.
[1]: https://github.com/kernel-patches/bpf/actions/runs/6713177520/job/18244865326?pr=5909
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20231101032455.3808547-4-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | tools/testing/selftests/bpf/map_tests/map_percpu_stats.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/tools/testing/selftests/bpf/map_tests/map_percpu_stats.c b/tools/testing/selftests/bpf/map_tests/map_percpu_stats.c index a98d6b94dd02..2ea36408816b 100644 --- a/tools/testing/selftests/bpf/map_tests/map_percpu_stats.c +++ b/tools/testing/selftests/bpf/map_tests/map_percpu_stats.c @@ -141,6 +141,7 @@ struct upsert_opts { __u32 map_type; int map_fd; __u32 n; + bool retry_for_nomem; }; static int create_small_hash(void) @@ -154,6 +155,11 @@ static int create_small_hash(void) return map_fd; } +static bool retry_for_nomem_fn(int err) +{ + return err == ENOMEM; +} + static void *patch_map_thread(void *arg) { /* 8KB is enough for 1024 CPUs. And it is shared between N_THREADS. */ @@ -175,7 +181,12 @@ static void *patch_map_thread(void *arg) val_ptr = &val; } - ret = bpf_map_update_elem(opts->map_fd, &i, val_ptr, 0); + /* 2 seconds may be enough ? */ + if (opts->retry_for_nomem) + ret = map_update_retriable(opts->map_fd, &i, val_ptr, 0, + 40, retry_for_nomem_fn); + else + ret = bpf_map_update_elem(opts->map_fd, &i, val_ptr, 0); CHECK(ret < 0, "bpf_map_update_elem", "key=%d error: %s\n", i, strerror(errno)); if (opts->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) @@ -296,6 +307,13 @@ static void __test(int map_fd) else opts.n /= 2; + /* per-cpu bpf memory allocator may not be able to allocate per-cpu + * pointer successfully and it can not refill free llist timely, and + * bpf_map_update_elem() will return -ENOMEM. so just retry to mitigate + * the problem temporarily. + */ + opts.retry_for_nomem = is_percpu(opts.map_type) && (info.map_flags & BPF_F_NO_PREALLOC); + /* * Upsert keys [0, n) under some competition: with random values from * N_THREADS threads. Check values, then delete all elements and check |