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