[PATCH bpf-next] bpf: show in bpftool map overview whether btf is available

[PATCH bpf-next] bpf: show in bpftool map overview whether btf is available

[Daniel Borkmann]

For a quick overview in 'bpftool map' display 'btf' if it's
available for the dump for a specific map:

  # bpftool map list
  11: array  flags 0x0  btf
          key 4B  value 20B  max_entries 40  memlock 4096B

  # bpftool --json --pretty map list
  [{
          "id": 11,
          "type": "array",
          "flags": 0,
          "btf_available": true,
          "bytes_key": 4,
          "bytes_value": 20,
          "max_entries": 40,
          "bytes_memlock": 4096
      }
  ]

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
---
 tools/bpf/bpftool/map.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
index 9c81918..2cc4741 100644
--- a/tools/bpf/bpftool/map.c
+++ b/tools/bpf/bpftool/map.c
@@ -490,6 +490,8 @@ static int show_map_close_json(int fd, struct bpf_map_info *info)
 
 	jsonw_name(json_wtr, "flags");
 	jsonw_printf(json_wtr, "%d", info->map_flags);
+	jsonw_name(json_wtr, "btf_available");
+	jsonw_bool(json_wtr, info->btf_key_type_id && info->btf_value_type_id);
 
 	print_dev_json(info->ifindex, info->netns_dev, info->netns_ino);
 
@@ -535,6 +537,8 @@ static int show_map_close_plain(int fd, struct bpf_map_info *info)
 		printf("name %s  ", info->name);
 
 	printf("flags 0x%x", info->map_flags);
+	if (info->btf_key_type_id && info->btf_value_type_id)
+		printf("  btf");
 	print_dev_plain(info->ifindex, info->netns_dev, info->netns_ino);
 	printf("\n");
 	printf("\tkey %uB  value %uB  max_entries %u",
-- 
2.9.5

Re: [PATCH bpf-next] bpf: show in bpftool map overview whether btf is available

[Martin KaFai Lau]

On Wed, Jul 18, 2018 at 11:19:42AM +0200, Daniel Borkmann wrote:
> For a quick overview in 'bpftool map' display 'btf' if it's
> available for the dump for a specific map:
> 
>   # bpftool map list
>   11: array  flags 0x0  btf
>           key 4B  value 20B  max_entries 40  memlock 4096B
> 
>   # bpftool --json --pretty map list
>   [{
>           "id": 11,
>           "type": "array",
>           "flags": 0,
>           "btf_available": true,
>           "bytes_key": 4,
>           "bytes_value": 20,
>           "max_entries": 40,
>           "bytes_memlock": 4096
>       }
>   ]
> 
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>

Re: [PATCH bpf-next] bpf: show in bpftool map overview whether btf is available

[Jakub Kicinski]

On Wed, 18 Jul 2018 11:19:42 +0200, Daniel Borkmann wrote:
> For a quick overview in 'bpftool map' display 'btf' if it's
> available for the dump for a specific map:
> 
>   # bpftool map list
>   11: array  flags 0x0  btf
>           key 4B  value 20B  max_entries 40  memlock 4096B
> 
>   # bpftool --json --pretty map list
>   [{
>           "id": 11,
>           "type": "array",
>           "flags": 0,
>           "btf_available": true,
>           "bytes_key": 4,
>           "bytes_value": 20,
>           "max_entries": 40,
>           "bytes_memlock": 4096
>       }
>   ]
> 
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

Hmm.. would it make sense to provide the actual BTF IDs instead of just
yes/no?  At least in JSON?

Re: [PATCH bpf-next] bpf: show in bpftool map overview whether btf is available

[Daniel Borkmann]

On 07/18/2018 08:08 PM, Jakub Kicinski wrote:
> On Wed, 18 Jul 2018 11:19:42 +0200, Daniel Borkmann wrote:
>> For a quick overview in 'bpftool map' display 'btf' if it's
>> available for the dump for a specific map:
>>
>>   # bpftool map list
>>   11: array  flags 0x0  btf
>>           key 4B  value 20B  max_entries 40  memlock 4096B
>>
>>   # bpftool --json --pretty map list
>>   [{
>>           "id": 11,
>>           "type": "array",
>>           "flags": 0,
>>           "btf_available": true,
>>           "bytes_key": 4,
>>           "bytes_value": 20,
>>           "max_entries": 40,
>>           "bytes_memlock": 4096
>>       }
>>   ]
>>
>> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> 
> Hmm.. would it make sense to provide the actual BTF IDs instead of just
> yes/no?  At least in JSON?

Yeah that sounds reasonable to me. I think in that case it needs to be
BTF id as well as key and value id inside that BTF object to make some
sense out of it (BTF id alone would not be enough).

Probably makes sense to show the same information in plain text output
then.