// SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2019 Facebook #include <linux/bpf.h> #include <linux/version.h> #include <bpf/bpf_helpers.h> struct hmap_elem { volatile int cnt; struct bpf_spin_lock lock; int test_padding; }; struct { __uint(type, BPF_MAP_TYPE_HASH); __uint(max_entries, 1); __type(key, int); __type(value, struct hmap_elem); } hmap SEC(".maps"); struct cls_elem { struct bpf_spin_lock lock; volatile int cnt; }; struct { __uint(type, BPF_MAP_TYPE_CGROUP_STORAGE); __type(key, struct bpf_cgroup_storage_key); __type(value, struct cls_elem); } cls_map SEC(".maps"); struct bpf_vqueue { struct bpf_spin_lock lock; /* 4 byte hole */ unsigned long long lasttime; int credit; unsigned int rate; }; struct { __uint(type, BPF_MAP_TYPE_ARRAY); __uint(max_entries, 1); __type(key, int); __type(value, struct bpf_vqueue); } vqueue SEC(".maps"); #define CREDIT_PER_NS(delta, rate) (((delta) * rate) >> 20) SEC("spin_lock_demo") int bpf_sping_lock_test(struct __sk_buff *skb) { volatile int credit = 0, max_credit = 100, pkt_len = 64; struct hmap_elem zero = {}, *val; unsigned long long curtime; struct bpf_vqueue *q; struct cls_elem *cls; int key = 0; int err = 0; val = bpf_map_lookup_elem(&hmap, &key); if (!val) { bpf_map_update_elem(&hmap, &key, &zero, 0); val = bpf_map_lookup_elem(&hmap, &key); if (!val) { err = 1; goto err; } } /* spin_lock in hash map run time test */ bpf_spin_lock(&val->lock); if (val->cnt) val->cnt--; else val->cnt++; if (val->cnt != 0 && val->cnt != 1) err = 1; bpf_spin_unlock(&val->lock); /* spin_lock in array. virtual queue demo */ q = bpf_map_lookup_elem(&vqueue, &key); if (!q) goto err; curtime = bpf_ktime_get_ns(); bpf_spin_lock(&q->lock); q->credit += CREDIT_PER_NS(curtime - q->lasttime, q->rate); q->lasttime = curtime; if (q->credit > max_credit) q->credit = max_credit; q->credit -= pkt_len; credit = q->credit; bpf_spin_unlock(&q->lock); /* spin_lock in cgroup local storage */ cls = bpf_get_local_storage(&cls_map, 0); bpf_spin_lock(&cls->lock); cls->cnt++; bpf_spin_unlock(&cls->lock); err: return err; } char _license[] SEC("license") = "GPL";