Re: [PATCH bpf-next] samples: bpf: refactor xdp_sample_pkts_kern with BTF-defined map

On Wed, Sep 9, 2020 at 8:24 AM Andrii Nakryiko
[off-list ref] wrote:

On Sat, Sep 5, 2020 at 8:41 AM Daniel T. Lee [off-list ref] wrote:

quoted

Most of the samples were converted to use the new BTF-defined MAP as
they moved to libbbpf, but some of the samples were missing.

Instead of using the previous BPF MAP definition, this commit refactors
xdp_sample_pkts_kern MAP definition with the new BTF-defined MAP format.

Signed-off-by: Daniel T. Lee <redacted>
---
 samples/bpf/xdp_sample_pkts_kern.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/samples/bpf/xdp_sample_pkts_kern.c b/samples/bpf/xdp_sample_pkts_kern.c
index 33377289e2a8..b15172b7d455 100644
--- a/samples/bpf/xdp_sample_pkts_kern.c
+++ b/samples/bpf/xdp_sample_pkts_kern.c

@@ -7,12 +7,12 @@
 #define SAMPLE_SIZE 64ul
 #define MAX_CPUS 128

-struct bpf_map_def SEC("maps") my_map = {
-       .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
-       .key_size = sizeof(int),
-       .value_size = sizeof(u32),
-       .max_entries = MAX_CPUS,
-};
+struct {
+       __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+       __uint(key_size, sizeof(int));
+       __uint(value_size, sizeof(u32));
+       __uint(max_entries, MAX_CPUS);

if you drop max_entries property, libbpf will set it to the maximum
configured number of CPUs on the host, which is what you probably
want. Do you might sending v2 without MAX_CPUS (check if macro is
still used anywhere else). Thanks!

Thanks for your time and effort for the review.

I'll check and send the next version of patch.

quoted

+} my_map SEC(".maps");

 SEC("xdp_sample")
 int xdp_sample_prog(struct xdp_md *ctx)
--
2.25.1

-- 
Best,
Daniel T. Lee