On Wed, Oct 20, 2021 at 10:59 AM Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> wrote: > > On Tue, Oct 12, 2021 at 8:29 AM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote: > > > > On Mon, Oct 11, 2021 at 8:45 PM Andrii Nakryiko > > <andrii.nakryiko@xxxxxxxxx> wrote: > > > > > > On Mon, Oct 11, 2021 at 11:24 PM Alexei Starovoitov <ast@xxxxxx> wrote: > > > > > > > > On 10/8/21 2:44 PM, Toke Høiland-Jørgensen wrote: > > > > > > > > > > Hmm, so introduce a new 'map_name_long' field, and on query the kernel > > > > > will fill in the old map_name with a truncated version, and put the full > > > > > name in the new field? Yeah, I guess that would work too! > > > > > > > > Let's start storing full map names in BTF instead. > > > > Like we do already for progs. > > > > Some tools already fetch full prog names this way. > > > > > > We do have those names in BTF. Each map has either corresponding VAR > > > or DATASEC. The problem is that we don't know which. > > > > > > Are you proposing to add some extra "btf_def_type_id" field to specify > > > BTF type ID of what "defines" the map (VAR or DATASEC)? That would > > > work. Would still require UAPI and kernel changes, of course. > > > > > > The reason Toke and others were asking to preserve that object name > > > prefix for .rodata/.data maps was different though, and won't be > > > addressed by the above. Even if you know the BTF VAR/DATASEC, you > > > don't know the "object name" associated with the map. And the kernel > > > doesn't know because it's purely libbpf's abstraction. And sometimes > > > that abstraction doesn't make sense (e.g., if we create a map that's > > > pinned and reused from multiple BPF apps/objects). > > > > [..] > > > > > We do have BPF metadata that Stanislav added a while ago, so maybe we > > > should just punt that problem to that? I'd love to have clean > > > ".rodata" and ".data" names, of course. > > > > Are you suggesting we add some option to associate the metadata with > > the maps (might be an option)? IIRC, the metadata can only be > > associated with the progs right now. > > Well, maps have associated BTF fd, when they are created, no? So you > can find all the same metadata for the map, no? I guess that's true, we can store this metadata in the map itself using something like existing bpf_metadata_ prefix.
