| // SPDX-License-Identifier: GPL-2.0 |
| #include <vmlinux.h> |
| #include <bpf/bpf_helpers.h> |
| |
| struct { |
| __uint(type, BPF_MAP_TYPE_LRU_HASH); |
| __uint(max_entries, 64); |
| __type(key, __u32); |
| __type(value, __u64); |
| } lru_map SEC(".maps"); |
| |
| int hits; |
| |
| SEC("perf_event") |
| int oncpu(void *ctx) |
| { |
| /* |
| * Key range deliberately wider than max_entries to force LRU |
| * eviction on every other update. |
| */ |
| __u32 key = bpf_get_prandom_u32() % 128; |
| bool do_update = bpf_get_prandom_u32() & 1; |
| __u64 val = 1; |
| |
| if (do_update) |
| bpf_map_update_elem(&lru_map, &key, &val, BPF_ANY); |
| else |
| bpf_map_delete_elem(&lru_map, &key); |
| __sync_fetch_and_add(&hits, 1); |
| return 0; |
| } |
| |
| char _license[] SEC("license") = "GPL"; |
