Re: [PATCH bpf-next v7 07/11] bpftool: Generate skeleton for global percpu data

[Leon Hwang <leon.hwang@linux.dev>]

On 24/6/26 06:46, Andrii Nakryiko wrote:
> On Mon, Jun 22, 2026 at 7:37 AM Leon Hwang <leon.hwang@linux.dev> wrote:
[...]
>> @@ -263,13 +268,12 @@ static bool is_mmapable_map(const struct bpf_map *map, char *buf, size_t sz)
>>                 return true;
>>         }
>>
>> -       if (!bpf_map__is_internal(map) || !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
>> -               return false;
>> -
>> -       if (!get_map_ident(map, buf, sz))
>> -               return false;
>> +       if (bpf_map__is_internal(map) &&
>> +           ((bpf_map__map_flags(map) & BPF_F_MMAPABLE) || bpf_map_is_percpu_data(map)) &&
>> +           get_map_ident(map, buf, sz))
>> +               return true;
>>
> 
> just add `if (bpf_map_is_percpu_data(map) return true;`? maybe also
> move get_map_ident check a bit earlier. I think that will be a bit
> cleaner, this condition is quite hard to follow
> 

Makes sense.

With adding the helper bpf_map_is_skel_data(), will this change looks
more readable?


+static bool bpf_map_is_skel_data(const struct bpf_map *map)
+{
+       return bpf_map__is_internal(map) &&
+               ((bpf_map__map_flags(map) & BPF_F_MMAPABLE) ||
+                bpf_map__type(map) == BPF_MAP_TYPE_PERCPU_ARRAY);
+}
+
 static bool is_mmapable_map(const struct bpf_map *map, char *buf,
size_t sz)
 {
        size_t tmp_sz;
@@ -263,7 +274,7 @@ static bool is_mmapable_map(const struct bpf_map
*map, char *buf, size_t sz)
                return true;
        }

-       if (!bpf_map__is_internal(map) || !(bpf_map__map_flags(map) &
BPF_F_MMAPABLE))
+       if (!bpf_map_is_skel_data(map))
                return false;

        if (!get_map_ident(map, buf, sz))


>> -       return true;
>> +       return false;
>>  }
>>
>>  static int codegen_datasecs(struct bpf_object *obj, const char *obj_name)
>> @@ -343,6 +347,9 @@ static int codegen_subskel_datasecs(struct bpf_object *obj, const char *obj_name
>>                 if (!is_mmapable_map(map, map_ident, sizeof(map_ident)))
>>                         continue;
>>
>> +               if (bpf_map_is_percpu_data(map))
>> +                       continue;
>> +
>>                 sec = find_type_for_map(btf, map_ident);
>>                 if (!sec)
>>                         continue;
>> @@ -669,7 +676,7 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
>>                 if (!get_map_ident(map, ident, sizeof(ident)))
>>                         continue;
>>                 if (bpf_map__is_internal(map) &&
>> -                   (bpf_map__map_flags(map) & BPF_F_MMAPABLE))
>> +                   ((bpf_map__map_flags(map) & BPF_F_MMAPABLE) || bpf_map_is_percpu_data(map)))
> 
> also we can add a helper to check if it's an internal map with a
> dedicated data section in the skeleton (too lazy to think of a good
> name right now.. ;)
> 

How about bpf_map_is_skel_data()?

Then, this 'if' will be updated as 'if (bpf_map_is_skel_data(map))'.

Thanks,
Leon

>>                         printf("\tskel_free_map_data(skel->%1$s, skel->maps.%1$s.initial_value, %2$zu);\n",
>>                                ident, bpf_map_mmap_sz(map));
>>                 codegen("\
> 
> [...]