helper_fill_hashmap() is used also on parallel and stress map tests. Those are consistently failing with ENOMEM on kernels built with PREEMPT_RT if preallocation is disabled. The failure is transient and only called by the memory cache refill running in a preemptible irq_work, which can easily stall in case of contention.
Use a retriable update in those cases to handle transient ENOMEM and make the test more stable also on PREEMPT_RT. Also fix the sign of the value printed in case of error (strerror() expects a positive errno while updates return it negative). Signed-off-by: Gabriele Monaco <[email protected]> --- tools/testing/selftests/bpf/test_maps.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/bpf/test_maps.c b/tools/testing/selftests/bpf/test_maps.c index ccc5acd55f..c32da7bd8b 100644 --- a/tools/testing/selftests/bpf/test_maps.c +++ b/tools/testing/selftests/bpf/test_maps.c @@ -260,6 +260,16 @@ static void test_hashmap_percpu(unsigned int task, void *data) close(fd); } +#define MAP_RETRIES 20 + +static bool can_retry(int err) +{ + return (err == EAGAIN || err == EBUSY || + ((err == ENOMEM || err == E2BIG) && + map_opts.map_flags == BPF_F_NO_PREALLOC)); +} + + #define VALUE_SIZE 3 static int helper_fill_hashmap(int max_entries) { @@ -274,10 +284,11 @@ static int helper_fill_hashmap(int max_entries) for (i = 0; i < max_entries; i++) { key = i; value[0] = key; - ret = bpf_map_update_elem(fd, &key, value, BPF_NOEXIST); + ret = map_update_retriable(fd, &key, value, BPF_NOEXIST, + MAP_RETRIES, can_retry); CHECK(ret != 0, "can't update hashmap", - "err: %s\n", strerror(ret)); + "err: %s\n", strerror(-ret)); } return fd; @@ -1392,17 +1403,9 @@ static void test_map_stress(void) #define DO_UPDATE 1 #define DO_DELETE 0 -#define MAP_RETRIES 20 #define MAX_DELAY_US 50000 #define MIN_DELAY_RANGE_US 5000 -static bool can_retry(int err) -{ - return (err == EAGAIN || err == EBUSY || - ((err == ENOMEM || err == E2BIG) && - map_opts.map_flags == BPF_F_NO_PREALLOC)); -} - int map_update_retriable(int map_fd, const void *key, const void *value, int flags, int attempts, retry_for_error_fn need_retry) { base-commit: 2d3090a8aeb596a26935db0955d46c9a5db5c6ce -- 2.54.0
