When the bpf ring buffer is full, new events can not be recorded util the consumer consumes some events to free space. This may cause critical events to be discarded, such as in fault diagnostic, where recent events are more critical than older ones. So add ovewrite mode for bpf ring buffer. In this mode, the new event overwrites the oldest event when the buffer is full. v2: - remove libbpf changes (Andrii) - update overwrite benchmark v1: https://lore.kernel.org/bpf/20250804022101.2171981-1-xukuohai@xxxxxxxxxxxxxxx/ Xu Kuohai (3): bpf: Add overwrite mode for bpf ring buffer selftests/bpf: Add test for overwrite ring buffer selftests/bpf/benchs: Add producer and overwrite bench for ring buffer include/uapi/linux/bpf.h | 4 + kernel/bpf/ringbuf.c | 159 +++++++++++++++--- tools/include/uapi/linux/bpf.h | 4 + tools/testing/selftests/bpf/Makefile | 3 +- tools/testing/selftests/bpf/bench.c | 2 + .../selftests/bpf/benchs/bench_ringbufs.c | 95 ++++++++++- .../bpf/benchs/run_bench_ringbufs.sh | 4 + .../selftests/bpf/prog_tests/ringbuf.c | 74 ++++++++ .../selftests/bpf/progs/ringbuf_bench.c | 10 ++ .../bpf/progs/test_ringbuf_overwrite.c | 98 +++++++++++ 10 files changed, 418 insertions(+), 35 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/test_ringbuf_overwrite.c -- 2.43.0
