1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
3
4 #include <vmlinux.h>
5 #include <string.h>
6 #include <stdbool.h>
7 #include <bpf/bpf_helpers.h>
8 #include <bpf/bpf_tracing.h>
9 #include "bpf_misc.h"
10
11 #define ENTRIES 128
12
13 char _license[] SEC("license") = "GPL";
14
15 __u64 callback_scheduled = 0;
16 __u64 callback_success = 0;
17 __u64 schedule_error = 0;
18 __u64 delete_success = 0;
19
20 struct elem {
21 __u32 count;
22 struct bpf_task_work tw;
23 };
24
25 struct {
26 __uint(type, BPF_MAP_TYPE_HASH);
27 __uint(map_flags, BPF_F_NO_PREALLOC);
28 __uint(max_entries, ENTRIES);
29 __type(key, int);
30 __type(value, struct elem);
31 } hmap SEC(".maps");
32
process_work(struct bpf_map * map,void * key,void * value)33 static int process_work(struct bpf_map *map, void *key, void *value)
34 {
35 __sync_fetch_and_add(&callback_success, 1);
36 return 0;
37 }
38
39 SEC("syscall")
schedule_task_work(void * ctx)40 int schedule_task_work(void *ctx)
41 {
42 struct elem empty_work = {.count = 0};
43 struct elem *work;
44 int key = 0, err;
45
46 key = bpf_ktime_get_ns() % ENTRIES;
47 work = bpf_map_lookup_elem(&hmap, &key);
48 if (!work) {
49 bpf_map_update_elem(&hmap, &key, &empty_work, BPF_NOEXIST);
50 work = bpf_map_lookup_elem(&hmap, &key);
51 if (!work)
52 return 0;
53 }
54 err = bpf_task_work_schedule_signal_impl(bpf_get_current_task_btf(), &work->tw, &hmap,
55 process_work, NULL);
56 if (err)
57 __sync_fetch_and_add(&schedule_error, 1);
58 else
59 __sync_fetch_and_add(&callback_scheduled, 1);
60 return 0;
61 }
62
63 SEC("syscall")
delete_task_work(void * ctx)64 int delete_task_work(void *ctx)
65 {
66 int key = 0, err;
67
68 key = bpf_get_prandom_u32() % ENTRIES;
69 err = bpf_map_delete_elem(&hmap, &key);
70 if (!err)
71 __sync_fetch_and_add(&delete_success, 1);
72 return 0;
73 }
74