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 | struct { |
9 | __uint(type, BPF_MAP_TYPE_TASK_STORAGE); |
10 | __uint(map_flags, BPF_F_NO_PREALLOC); |
11 | __type(key, int); |
12 | __type(value, int); |
13 | } task_storage SEC(".maps" ); |
14 | |
15 | long hits; |
16 | long gp_hits; |
17 | long gp_times; |
18 | long current_gp_start; |
19 | long unexpected; |
20 | bool postgp_seen; |
21 | |
22 | SEC("fentry/" SYS_PREFIX "sys_getpgid" ) |
23 | int get_local(void *ctx) |
24 | { |
25 | struct task_struct *task; |
26 | int idx; |
27 | int *s; |
28 | |
29 | idx = 0; |
30 | task = bpf_get_current_task_btf(); |
31 | s = bpf_task_storage_get(&task_storage, task, &idx, |
32 | BPF_LOCAL_STORAGE_GET_F_CREATE); |
33 | if (!s) |
34 | return 0; |
35 | |
36 | *s = 3; |
37 | bpf_task_storage_delete(&task_storage, task); |
38 | __sync_add_and_fetch(&hits, 1); |
39 | return 0; |
40 | } |
41 | |
42 | SEC("fentry/rcu_tasks_trace_pregp_step" ) |
43 | int pregp_step(struct pt_regs *ctx) |
44 | { |
45 | current_gp_start = bpf_ktime_get_ns(); |
46 | return 0; |
47 | } |
48 | |
49 | SEC("fentry/rcu_tasks_trace_postgp" ) |
50 | int postgp(struct pt_regs *ctx) |
51 | { |
52 | if (!current_gp_start && postgp_seen) { |
53 | /* Will only happen if prog tracing rcu_tasks_trace_pregp_step doesn't |
54 | * execute before this prog |
55 | */ |
56 | __sync_add_and_fetch(&unexpected, 1); |
57 | return 0; |
58 | } |
59 | |
60 | __sync_add_and_fetch(&gp_times, bpf_ktime_get_ns() - current_gp_start); |
61 | __sync_add_and_fetch(&gp_hits, 1); |
62 | current_gp_start = 0; |
63 | postgp_seen = true; |
64 | return 0; |
65 | } |
66 | |
67 | char _license[] SEC("license" ) = "GPL" ; |
68 | |