Andrii raised a concern that current uapi for bpf iterator map element is a little restrictive and not suitable for future potential complex customization. This is a valid suggestion, considering people may indeed add more complex custimization to the iterator, e.g., cgroup_id + user_id, etc. for task or task_file. Another example might be map_id plus additional control so that the bpf iterator may bail out a bucket earlier if a bucket has too many elements which may hold lock too long and impact other parts of systems.
Patch #1 modified uapi with kernel changes. Patch #2 adjusted libbpf api accordingly. Yonghong Song (2): bpf: change uapi for bpf iterator map elements libbpf: support new uapi for map element bpf iterator include/linux/bpf.h | 10 ++++--- include/uapi/linux/bpf.h | 15 +++++----- kernel/bpf/bpf_iter.c | 52 +++++++++++++++------------------- kernel/bpf/map_iter.c | 37 ++++++++++++++++++------ kernel/bpf/syscall.c | 2 +- net/core/bpf_sk_storage.c | 37 ++++++++++++++++++------ tools/include/uapi/linux/bpf.h | 15 +++++----- tools/lib/bpf/bpf.c | 4 ++- tools/lib/bpf/bpf.h | 5 ++-- tools/lib/bpf/libbpf.c | 7 +++-- 10 files changed, 115 insertions(+), 69 deletions(-) -- 2.24.1
