On Sun, Oct 20, 2019 at 7:25 PM Alexei Starovoitov
[off-list ref] wrote:

On Sun, Oct 20, 2019 at 10:13:49AM +0200, Magnus Karlsson wrote:

quoted

On Sat, Oct 19, 2019 at 11:48 AM Alexei Starovoitov
[off-list ref] wrote:

quoted

On Fri, Oct 18, 2019 at 11:33:40AM +0200, Magnus Karlsson wrote:

quoted

+
+   #include <linux/bpf.h>
+   #include "bpf_helpers.h"
+
+   #define MAX_SOCKS 16
+
+   struct {
+        __uint(type, BPF_MAP_TYPE_XSKMAP);
+        __uint(max_entries, MAX_SOCKS);
+        __uint(key_size, sizeof(int));
+        __uint(value_size, sizeof(int));
+   } xsks_map SEC(".maps");
+
+   struct {
+        __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+        __uint(max_entries, 1);
+        __type(key, int);
+        __type(value, unsigned int);
+   } rr_map SEC(".maps");

hmm. does xsks_map compile?

Yes. Actually, I wrote a new sample to demonstrate this feature and to
test the code above. I will send that patch set (contains some small
additions to libbpf also to be able to support this) to bpf-next.
Though, if I used the __type declarations of the rr_map PERCPU_ARRAY I
got this warning: "pr_warning("Error in
bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n")", so I had
to change it to the type above that is also used for SOCKMAP. Some
enablement that is missing for XSKMAP? Have not dug into it.

Ahh. Right. xskmap explicitly prohibits BTF for key/value.
const struct bpf_map_ops xsk_map_ops = {
        ...
        .map_check_btf = map_check_no_btf,
};
I guess it's time to add support for it.

Agreed. I will implement that in a separate patch set for bpf-next and
include a patch to update the documentation too in that patch set.