Alan Maguire wrote on Thu, Jun 15, 2023 at 03:31:49PM +0100: > However the problem I suspect is this: > > 51 .debug_info 0a488b55 0000000000000000 0000000000000000 026f8d20 > 2**0 > CONTENTS, READONLY, DEBUGGING > [...] > > The debug info hasn't been stripped, so I suspect the packaging spec > file or equivalent - in perhaps trying to preserve the .BTF section - > is preserving debug info too. DWARF needs to be there at BTF > generation time in vmlinux but is usually stripped for non-debug > packages. Thanks Alan and Eduard! I guess I should have checked that first, it helps. We're not stripping anything in vmlinuz for other archs -- the linker script already should be including only the bare minimum to decompress itself (+compressed useful bits), so I guess it's a Kbuild issue for the arch. We can add a strip but I unfortunately have no way of testing ppc build, I'll ask around the build linux-kbuild and linuxppc-dev lists if that's expected; it shouldn't be that bad now that's figured out. > FYI we're aiming to make BTF module-loadable via CONFIG_DEBUG_INFO_BTF=m > in the future, I'm hoping to get an RFC patch out for that soon once > other BTF-related issues are sorted. Hope this helps Oh, that's interesting -- I assume that'll only change the 'built-in' BTF info? Or will that also split BTF info in other modules as e.g. modfoo_btf.ko? For x86_64 the size increase of vmlinuz itself is rather acceptable (<2MB), but the sheer amount of modules (the -lts package has over 3k modules...) means that even a small size increase for each module ends up taking proportionally a high amount of space (+20MB from 90MB), so being able to package separately would be appreciated (alpine likes splitting optional features in subpackages) Packaging-wise I'm not sure it'd make sense to keep the overhead in other modules and just split the 'main' btf infos. Otoh even if it doesn't help with packaging, having a smaller vmlinuz means faster boot and lower kernel memory footprint (I think *2?) for people who don't need it, so I think it's a good idea and we'll probably enable it once it becomes available. Thanks for the heads up! -- Dominique Martinet | Asmadeus
