On Mon, Feb 8, 2021 at 4:28 PM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote: > > Gilad Reti <gilad.reti@xxxxxxxxx> writes: > > > On Mon, Feb 8, 2021 at 1:42 PM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote: > >> > >> Gilad Reti <gilad.reti@xxxxxxxxx> 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? :) > Sure, I can, but I think we should avoid that. As I said this forces the user to know libbpf's pin path naming algorithm, which is not part of the libbpf api afaik. I think that if we have a method to pin all maps at a specific path there should also be a method for reusing them all from this path, either by exposing the function that builds the pin path, or a function that sets all the paths from a root path. > -Toke >
