On Mon, Jul 14, 2025 at 9:41 PM Menglong Dong <menglong.dong@xxxxxxxxx> wrote: > > > On 7/15/25 06:07, Andrii Nakryiko wrote: > > On Thu, Jul 3, 2025 at 5:22 AM Menglong Dong <menglong8.dong@xxxxxxxxx> wrote: > >> For now, the libbpf find the btf type id by loop all the btf types and > >> compare its name, which is inefficient if we have many functions to > >> lookup. > >> > >> We add the "use_hash" to the function args of find_kernel_btf_id() to > >> indicate if we should lookup the btf type id by hash. The hash table will > >> be initialized if it has not yet. > > Or we could build hashtable-based index outside of struct btf for a > > specific use case, because there is no one perfect hashtable-based > > indexing that can be done generically (e.g., just by name, or > > name+kind, or kind+name, or some more complicated lookup key) and > > cover all potential use cases. I'd prefer not to get into a problem of > > defining and building indexes and leave it to callers (even if the > > caller is other part of libbpf itself). > > > I think that works. We can define a global hash table in libbpf.c, > and add all the btf type to it. I'll redesign this part, and make it > separate with the btf. No global things, please. It can be held per-bpf_object, or even constructed on demand during attachment and then freed. No need for anything global. > > Thanks! > Menglong Dong > > >> Signed-off-by: Menglong Dong <dongml2@xxxxxxxxxxxxxxx> > >> --- > >> tools/lib/bpf/btf.c | 102 +++++++++++++++++++++++++++++++++++++++ > >> tools/lib/bpf/btf.h | 6 +++ > >> tools/lib/bpf/libbpf.c | 37 +++++++++++--- > >> tools/lib/bpf/libbpf.map | 3 ++ > >> 4 files changed, 140 insertions(+), 8 deletions(-) > >> > > [...] > >
