On 2/21/25 6:47 AM, Alan Maguire wrote: > On 19/02/2025 21:05, Ihor Solodrai wrote: >> This patch series implements emitting appropriate BTF type tags for >> argument and return types of kfuncs marked with KF_ARENA_* flags. >> >> For additional context see the description of BPF patch >> "bpf: define KF_ARENA_* flags for bpf_arena kfuncs" [1]. >> >> The feature depends on recent changes in libbpf [2]. >> >> [1] https://lore.kernel.org/bpf/20250206003148.2308659-1-ihor.solodrai@xxxxxxxxx/ >> [2] https://lore.kernel.org/bpf/20250130201239.1429648-1-ihor.solodrai@xxxxxxxxx/ >> > > hi Ihor, just realized that given that this change depends on recent > libbpf changes, we should look at updating the series to include a patch > updating our libbpf subproject checkpoint commit for libbpf to get those > changes for the case where the libbpf submodule is built (the default > these days). We should probably have a patch (pahole: sync with > libbpf-1.6) to cover this. An example of a subproject commit patch can > be found at > > https://lore.kernel.org/dwarves/20240729111317.140816-2-alan.maguire@xxxxxxxxxx/ > > However I don't think those bpf-next libbpf changes have been synced > with the github libbpf repo yet. If the next libbf sync won't be for a > while, I don't think this has to block this work - we could just note > that it needs to explicitly be built with latest v1.6 via shared library > for testing purposes in the interim - but if there's a sync planned soon > it'd be great to roll that in too. Hi Alan. I've just submitted a PR to sync libbpf with upstream. https://github.com/libbpf/libbpf/pull/886 Will add a subproject commit patch. Andrii suggested pahole could use __weak declarations of libbpf API and detect if they are linked at runtime. This way it's not necessary to check for libbpf version. There are just a few places where we currently do that. What do you think if I add patches for that too? Thanks. > > Thanks! > > Alan > > > v2->v3: >> * Nits in patch #1 >> >> v1->v2: >> * Rewrite patch #1 refactoring btf_encoder__tag_kfuncs(): now the >> post-processing step is removed entirely, and kfuncs are tagged in >> btf_encoder__add_func(). >> * Nits and renames in patch #2 >> * Add patch #4 editing man pages >> >> v2: https://lore.kernel.org/dwarves/20250212201552.1431219-1-ihor.solodrai@xxxxxxxxx/ >> v1: https://lore.kernel.org/dwarves/20250207021442.155703-1-ihor.solodrai@xxxxxxxxx/ >> >> Ihor Solodrai (4): >> btf_encoder: refactor btf_encoder__tag_kfuncs() >> btf_encoder: emit type tags for bpf_arena pointers >> pahole: introduce --btf_feature=attributes >> man-pages: describe attributes and remove reproducible_build >> >> btf_encoder.c | 279 +++++++++++++++++++++++---------------------- >> dwarves.h | 1 + >> man-pages/pahole.1 | 7 +- >> pahole.c | 11 ++ >> 4 files changed, 158 insertions(+), 140 deletions(-) >> >
