1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
// 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 {
__u32 type;
__u32 max_entries;
int *key;
struct hmap_elem *value;
} hmap SEC(".maps") = {
.type = BPF_MAP_TYPE_HASH,
.max_entries = 1,
};
struct cls_elem {
struct bpf_spin_lock lock;
volatile int cnt;
};
struct {
__u32 type;
struct bpf_cgroup_storage_key *key;
struct cls_elem *value;
} cls_map SEC(".maps") = {
.type = BPF_MAP_TYPE_CGROUP_STORAGE,
};
struct bpf_vqueue {
struct bpf_spin_lock lock;
/* 4 byte hole */
unsigned long long lasttime;
int credit;
unsigned int rate;
};
struct {
__u32 type;
__u32 max_entries;
int *key;
struct bpf_vqueue *value;
} vqueue SEC(".maps") = {
.type = BPF_MAP_TYPE_ARRAY,
.max_entries = 1,
};
#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";
|