github.com/cilium/ebpf runs integration tests with libbpf in a vm on CI. I recently did some work to increase the code coverage from that, and started experiencing OOM-kills in the VM. That led me down a rabbit hole looking at verifier memory allocation patterns. I didn't figure out what triggered the OOM-kills but refactored some often called memory allocation code. The key insight is that often times we don't need to do a full kfree / kmalloc, but can instead just reallocate. The first patch adds two helpers which do just that for the use cases in the verifier, which are sufficiently different that they can't use stock krealloc_array and friends. The series makes bpf_verif_scale about 10% faster in my VM set up, which is especially noticeable when running with KASAN enabled. Lorenz Bauer (3): bpf: verifier: improve function state reallocation bpf: verifier: use copy_array for jmp_history bpf: verifier: allocate idmap scratch in verifier env include/linux/bpf_verifier.h | 8 ++ kernel/bpf/verifier.c | 254 +++++++++++++++++------------------ 2 files changed, 128 insertions(+), 134 deletions(-) -- 2.27.0
