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selftests/xsk: Read current MAX_SKB_FRAGS from sysctl knob

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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.

Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20240910124129.289874-1-maciej.fijalkowski@intel.com
This commit is contained in:
Maciej Fijalkowski 2024-09-10 14:41:29 +02:00 committed by Daniel Borkmann
parent 6b083650a3
commit d41905b3bb
2 changed files with 38 additions and 6 deletions
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43
tools/testing/selftests/bpf/xskxceiver.c
View File

@ -324,6 +324,25 @@ out:
return zc_avail; 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[] = { static struct option long_options[] = {
{"interface", required_argument, 0, 'i'}, {"interface", required_argument, 0, 'i'},
{"busy-poll", no_argument, 0, 'b'}, {"busy-poll", no_argument, 0, 'b'},
@ -2244,13 +2263,24 @@ static int testapp_poll_rxq_tmout(struct test_spec *test)
static int testapp_too_many_frags(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; 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; max_frags = test->ifobj_tx->xdp_zc_max_segs;
else } else {
max_frags = XSK_DESC__MAX_SKB_FRAGS; 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; test->mtu = MAX_ETH_JUMBO_SIZE;
@ -2280,7 +2310,10 @@ static int testapp_too_many_frags(struct test_spec *test)
pkts[2 * max_frags + 1].valid = true; pkts[2 * max_frags + 1].valid = true;
pkt_stream_generate_custom(test, pkts, 2 * max_frags + 2); 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) static int xsk_load_xdp_programs(struct ifobject *ifobj)

1
tools/testing/selftests/bpf/xskxceiver.h
View File

@ -55,7 +55,6 @@
#define XSK_UMEM__LARGE_FRAME_SIZE (3 * 1024) #define XSK_UMEM__LARGE_FRAME_SIZE (3 * 1024)
#define XSK_UMEM__MAX_FRAME_SIZE (4 * 1024) #define XSK_UMEM__MAX_FRAME_SIZE (4 * 1024)
#define XSK_DESC__INVALID_OPTION (0xffff) #define XSK_DESC__INVALID_OPTION (0xffff)
#define XSK_DESC__MAX_SKB_FRAGS 18
#define HUGEPAGE_SIZE (2 * 1024 * 1024) #define HUGEPAGE_SIZE (2 * 1024 * 1024)
#define PKT_DUMP_NB_TO_PRINT 16 #define PKT_DUMP_NB_TO_PRINT 16
#define RUN_ALL_TESTS UINT_MAX #define RUN_ALL_TESTS UINT_MAX