On Mon, 1 Oct 2018 at 20:12, Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote: > > On 10/01/2018 12:45 PM, Lorenz Bauer wrote: > > This patch set adds a new flag BPF_F_ZERO_SEED, which allows > > forcing the seed used by hash maps to zero. This makes > > it possible to write deterministic tests. > > > > Based on an off-list conversation with Alexei Starovoitov and > > Daniel Borkmann. > > > > Lorenz Bauer (3): > > bpf: allow zero-initializing hash map seed > > tools: sync linux/bpf.h > > tools: add selftest for BPF_F_ZERO_SEED > > > > include/uapi/linux/bpf.h | 2 + > > kernel/bpf/hashtab.c | 8 ++- > > tools/include/uapi/linux/bpf.h | 2 + > > tools/testing/selftests/bpf/test_maps.c | 67 +++++++++++++++++++++---- > > 4 files changed, 66 insertions(+), 13 deletions(-) > > > > Please respin with proper SoB for each patch and non-empty commit > description. What does SoB mean? Point taken about the empty commit message. > I think patch 1 should also have a more elaborate > commit description on the use case for BPF_F_ZERO_SEED, and I This came out of the off-list discussion we had about map hash functions, where Alexei expressed concern that your change to randomise the seed might catch users off-guard. I personally don't have a use case, but decided to tackle it since it seemed a simple-ish fix to get acquainted with the code base. Maybe this isn't needed after all? > think also a better comment in the uapi header that this is only > meant for testing and not production use. Will do, if you decide that this is worth having in the first place. > > Thanks, > Daniel Lorenz -- Lorenz Bauer | Systems Engineer 25 Lavington St., London SE1 0NZ www.cloudflare.com
