Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2018 Facebook
3
4#include <linux/bpf.h>
5#include "bpf_helpers.h"
6
7#ifndef PERF_MAX_STACK_DEPTH
8#define PERF_MAX_STACK_DEPTH 127
9#endif
10
11struct bpf_map_def SEC("maps") control_map = {
12 .type = BPF_MAP_TYPE_ARRAY,
13 .key_size = sizeof(__u32),
14 .value_size = sizeof(__u32),
15 .max_entries = 1,
16};
17
18struct bpf_map_def SEC("maps") stackid_hmap = {
19 .type = BPF_MAP_TYPE_HASH,
20 .key_size = sizeof(__u32),
21 .value_size = sizeof(__u32),
22 .max_entries = 10000,
23};
24
25struct bpf_map_def SEC("maps") stackmap = {
26 .type = BPF_MAP_TYPE_STACK_TRACE,
27 .key_size = sizeof(__u32),
28 .value_size = sizeof(__u64) * PERF_MAX_STACK_DEPTH,
29 .max_entries = 10000,
30};
31
32/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */
33struct sched_switch_args {
34 unsigned long long pad;
35 char prev_comm[16];
36 int prev_pid;
37 int prev_prio;
38 long long prev_state;
39 char next_comm[16];
40 int next_pid;
41 int next_prio;
42};
43
44SEC("tracepoint/sched/sched_switch")
45int oncpu(struct sched_switch_args *ctx)
46{
47 __u32 key = 0, val = 0, *value_p;
48
49 value_p = bpf_map_lookup_elem(&control_map, &key);
50 if (value_p && *value_p)
51 return 0; /* skip if non-zero *value_p */
52
53 /* The size of stackmap and stackid_hmap should be the same */
54 key = bpf_get_stackid(ctx, &stackmap, 0);
55 if ((int)key >= 0)
56 bpf_map_update_elem(&stackid_hmap, &key, &val, 0);
57
58 return 0;
59}
60
61char _license[] SEC("license") = "GPL";
62__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */