1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
3
4#include "vmlinux.h"
5#include <bpf/bpf_helpers.h>
6#include "bpf_misc.h"
7
8#define HASHMAP_SZ 4194304
9
10struct {
11	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
12	__uint(max_entries, 1000);
13	__type(key, int);
14	__type(value, int);
15	__array(values, struct {
16		__uint(type, BPF_MAP_TYPE_TASK_STORAGE);
17		__uint(map_flags, BPF_F_NO_PREALLOC);
18		__type(key, int);
19		__type(value, int);
20	});
21} array_of_local_storage_maps SEC(".maps");
22
23struct {
24	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
25	__uint(max_entries, 1000);
26	__type(key, int);
27	__type(value, int);
28	__array(values, struct {
29		__uint(type, BPF_MAP_TYPE_HASH);
30		__uint(max_entries, HASHMAP_SZ);
31		__type(key, int);
32		__type(value, int);
33	});
34} array_of_hash_maps SEC(".maps");
35
36long important_hits;
37long hits;
38
39/* set from user-space */
40const volatile unsigned int use_hashmap;
41const volatile unsigned int hashmap_num_keys;
42const volatile unsigned int num_maps;
43const volatile unsigned int interleave;
44
45struct loop_ctx {
46	struct task_struct *task;
47	long loop_hits;
48	long loop_important_hits;
49};
50
51static int do_lookup(unsigned int elem, struct loop_ctx *lctx)
52{
53	void *map, *inner_map;
54	int idx = 0;
55
56	if (use_hashmap)
57		map = &array_of_hash_maps;
58	else
59		map = &array_of_local_storage_maps;
60
61	inner_map = bpf_map_lookup_elem(map, &elem);
62	if (!inner_map)
63		return -1;
64
65	if (use_hashmap) {
66		idx = bpf_get_prandom_u32() % hashmap_num_keys;
67		bpf_map_lookup_elem(inner_map, &idx);
68	} else {
69		bpf_task_storage_get(inner_map, lctx->task, &idx,
70				     BPF_LOCAL_STORAGE_GET_F_CREATE);
71	}
72
73	lctx->loop_hits++;
74	if (!elem)
75		lctx->loop_important_hits++;
76	return 0;
77}
78
79static long loop(u32 index, void *ctx)
80{
81	struct loop_ctx *lctx = (struct loop_ctx *)ctx;
82	unsigned int map_idx = index % num_maps;
83
84	do_lookup(map_idx, lctx);
85	if (interleave && map_idx % 3 == 0)
86		do_lookup(0, lctx);
87	return 0;
88}
89
90SEC("fentry/" SYS_PREFIX "sys_getpgid")
91int get_local(void *ctx)
92{
93	struct loop_ctx lctx;
94
95	lctx.task = bpf_get_current_task_btf();
96	lctx.loop_hits = 0;
97	lctx.loop_important_hits = 0;
98	bpf_loop(10000, &loop, &lctx, 0);
99	__sync_add_and_fetch(&hits, lctx.loop_hits);
100	__sync_add_and_fetch(&important_hits, lctx.loop_important_hits);
101	return 0;
102}
103
104char _license[] SEC("license") = "GPL";
105