On Tue, 2024-02-13 at 15:17 -0800, Andrii Nakryiko wrote: [...] > > So, at first I thought that having two maps is a bit of a hack. > > yep, that was my instinct as well > > > However, after trying to make it work with only one map I don't really > > like that either :) > > Can you elaborate? see my reply to Alexei, I wonder how did you think > about doing this? Relocations in the ELF file are against a new section: ".arena.1". This works nicely with logic in bpf_program__record_reloc(). If single map is used, we effectively need to track two indexes for the map section: - one used for relocations against map variables themselves (named "generic map reference relocation" in the function code); - one used for relocations against ".arena.1" (named "global data map relocation" in the function code). This spooked me off: - either bpf_object__init_internal_map() would have a specialized branch for arenas, as with current approach; - or bpf_program__record_reloc() would have a specialized branch for arenas, as with one map approach. Additionally, skel generation logic currently assumes that mmapable bindings would be generated only for internal maps, but that is probably not a big deal.
