On Tue, 10 Sept 2024 at 14:41, Maciej Fijalkowski
<maciej.fijalkowski@xxxxxxxxx> wrote:
>
> Currently, xskxceiver assumes that MAX_SKB_FRAGS value is always 17
> which is not true - since the introduction of BIG TCP this can now take
> any value between 17 to 45 via CONFIG_MAX_SKB_FRAGS.
>
> Adjust the TOO_MANY_FRAGS test case to read the currently configured
> MAX_SKB_FRAGS value by reading it from /proc/sys/net/core/max_skb_frags.
> If running system does not provide that sysctl file then let us try
> running the test with a default value.
Acked-by: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
> Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
> ---
>
> v2: instead of failing the test case when reading frag value from sysctl
> file did not succeed, use a default count and proceed with test [Magnus]
>
> tools/testing/selftests/bpf/xskxceiver.c | 43 +++++++++++++++++++++---
> tools/testing/selftests/bpf/xskxceiver.h | 1 -
> 2 files changed, 38 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/xskxceiver.c b/tools/testing/selftests/bpf/xskxceiver.c
> index 92af633faea8..11f047b8af75 100644
> --- a/tools/testing/selftests/bpf/xskxceiver.c
> +++ b/tools/testing/selftests/bpf/xskxceiver.c
> @@ -325,6 +325,25 @@ static bool ifobj_zc_avail(struct ifobject *ifobject)
> return zc_avail;
> }
>
> +#define MAX_SKB_FRAGS_PATH "/proc/sys/net/core/max_skb_frags"
> +static unsigned int get_max_skb_frags(void)
> +{
> + unsigned int max_skb_frags = 0;
> + FILE *file;
> +
> + file = fopen(MAX_SKB_FRAGS_PATH, "r");
> + if (!file) {
> + ksft_print_msg("Error opening %s\n", MAX_SKB_FRAGS_PATH);
> + return 0;
> + }
> +
> + if (fscanf(file, "%u", &max_skb_frags) != 1)
> + ksft_print_msg("Error reading %s\n", MAX_SKB_FRAGS_PATH);
> +
> + fclose(file);
> + return max_skb_frags;
> +}
> +
> static struct option long_options[] = {
> {"interface", required_argument, 0, 'i'},
> {"busy-poll", no_argument, 0, 'b'},
> @@ -2245,13 +2264,24 @@ static int testapp_poll_rxq_tmout(struct test_spec *test)
>
> static int testapp_too_many_frags(struct test_spec *test)
> {
> - struct pkt pkts[2 * XSK_DESC__MAX_SKB_FRAGS + 2] = {};
> + struct pkt *pkts;
> u32 max_frags, i;
> + int ret;
>
> - if (test->mode == TEST_MODE_ZC)
> + if (test->mode == TEST_MODE_ZC) {
> max_frags = test->ifobj_tx->xdp_zc_max_segs;
> - else
> - max_frags = XSK_DESC__MAX_SKB_FRAGS;
> + } else {
> + max_frags = get_max_skb_frags();
> + if (!max_frags) {
> + ksft_print_msg("Couldn't retrieve MAX_SKB_FRAGS from system, using default (17) value\n");
> + max_frags = 17;
> + }
> + max_frags += 1;
> + }
> +
> + pkts = calloc(2 * max_frags + 2, sizeof(struct pkt));
> + if (!pkts)
> + return TEST_FAILURE;
>
> test->mtu = MAX_ETH_JUMBO_SIZE;
>
> @@ -2281,7 +2311,10 @@ static int testapp_too_many_frags(struct test_spec *test)
> pkts[2 * max_frags + 1].valid = true;
>
> pkt_stream_generate_custom(test, pkts, 2 * max_frags + 2);
> - return testapp_validate_traffic(test);
> + ret = testapp_validate_traffic(test);
> +
> + free(pkts);
> + return ret;
> }
>
> static int xsk_load_xdp_programs(struct ifobject *ifobj)
> diff --git a/tools/testing/selftests/bpf/xskxceiver.h b/tools/testing/selftests/bpf/xskxceiver.h
> index 885c948c5d83..e46e823f6a1a 100644
> --- a/tools/testing/selftests/bpf/xskxceiver.h
> +++ b/tools/testing/selftests/bpf/xskxceiver.h
> @@ -55,7 +55,6 @@
> #define XSK_UMEM__LARGE_FRAME_SIZE (3 * 1024)
> #define XSK_UMEM__MAX_FRAME_SIZE (4 * 1024)
> #define XSK_DESC__INVALID_OPTION (0xffff)
> -#define XSK_DESC__MAX_SKB_FRAGS 18
> #define HUGEPAGE_SIZE (2 * 1024 * 1024)
> #define PKT_DUMP_NB_TO_PRINT 16
> #define RUN_ALL_TESTS UINT_MAX
> --
> 2.34.1
>
>
