Re: libbpf: pinning multiple progs from the same section

["Toke Høiland-Jørgensen" <toke@redhat.com>]

Gilad Reti <gilad.reti@gmail.com> writes:

> On Mon, Feb 8, 2021 at 1:42 PM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>>
>> Gilad Reti <gilad.reti@gmail.com> writes:
>>
>> > Also, is there a way to set the pin path to all maps/programs at once?
>> > For example, bpf_object__pin_maps pins all maps at a specific path,
>> > but as far as I was able to find there is no similar function to set
>> > the pin path for all maps only (without pinning) so that at loading
>> > time libbpf will try to reuse all maps. The only way to achieve a
>> > complete reuse of all maps that I could find is to "reverse engineer"
>> > libbpf's pin path generation algorithm (i.e. <path>/<map_name>) and
>> > set the pin path on each map before load.
>>
>> You can set the 'pinning' attribute in the map definition - add
>> '__uint(pinning, LIBBPF_PIN_BY_NAME);' to the map struct. By default
>> this will pin beneath /sys/fs/bpf, but you can customise that by setting
>> the pin_root_path attribute in bpf_object_open_opts.
>
> Yes, I am familiar with that feature, but it has some downsides:
> 1. I need to set it manually on every map (and in cases that I have
> only the compiled object file that would be hard).
> 2. It only works for bpf maps and not bpf programs.
> 3. It only works for bpf maps that are defined explicitly in the bpf
> code and not for implicit (inner) bpf maps (bss, rodata, etc).

Ah, right. Well, other than that I don't think there's a way to set pin
paths in bulk, other than by manually iterating and setting them one at
a time. But, erm, can't you just do that? :)

-Toke