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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Facebook
#include <linux/bpf.h>
#include <linux/version.h>
#include "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";
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