1bd4aed0eSJiong Wang // SPDX-License-Identifier: GPL-2.0
2bd4aed0eSJiong Wang // Copyright (c) 2018 Facebook
3bd4aed0eSJiong Wang
43087c61eSYafang Shao #include <vmlinux.h>
53e689141SToke Høiland-Jørgensen #include <bpf/bpf_helpers.h>
6bd4aed0eSJiong Wang
7bd4aed0eSJiong Wang #ifndef PERF_MAX_STACK_DEPTH
8bd4aed0eSJiong Wang #define PERF_MAX_STACK_DEPTH 127
9bd4aed0eSJiong Wang #endif
10bd4aed0eSJiong Wang
11df0b7792SAndrii Nakryiko struct {
12bc7430ccSAndrii Nakryiko __uint(type, BPF_MAP_TYPE_ARRAY);
13bc7430ccSAndrii Nakryiko __uint(max_entries, 1);
14bc7430ccSAndrii Nakryiko __type(key, __u32);
15bc7430ccSAndrii Nakryiko __type(value, __u32);
16bc7430ccSAndrii Nakryiko } control_map SEC(".maps");
17bd4aed0eSJiong Wang
18df0b7792SAndrii Nakryiko struct {
19bc7430ccSAndrii Nakryiko __uint(type, BPF_MAP_TYPE_HASH);
20bc7430ccSAndrii Nakryiko __uint(max_entries, 16384);
21bc7430ccSAndrii Nakryiko __type(key, __u32);
22bc7430ccSAndrii Nakryiko __type(value, __u32);
23bc7430ccSAndrii Nakryiko } stackid_hmap SEC(".maps");
24bd4aed0eSJiong Wang
25df0b7792SAndrii Nakryiko typedef __u64 stack_trace_t[PERF_MAX_STACK_DEPTH];
26df0b7792SAndrii Nakryiko
27df0b7792SAndrii Nakryiko struct {
28bc7430ccSAndrii Nakryiko __uint(type, BPF_MAP_TYPE_STACK_TRACE);
29bc7430ccSAndrii Nakryiko __uint(max_entries, 16384);
30bd368cb5SHengqi Chen __type(key, __u32);
31bd368cb5SHengqi Chen __type(value, stack_trace_t);
32bc7430ccSAndrii Nakryiko } stackmap SEC(".maps");
33bd4aed0eSJiong Wang
34df0b7792SAndrii Nakryiko struct {
35bc7430ccSAndrii Nakryiko __uint(type, BPF_MAP_TYPE_ARRAY);
36bc7430ccSAndrii Nakryiko __uint(max_entries, 16384);
37bc7430ccSAndrii Nakryiko __type(key, __u32);
388981e56fSAndrii Nakryiko __type(value, stack_trace_t);
39bc7430ccSAndrii Nakryiko } stack_amap SEC(".maps");
40bd4aed0eSJiong Wang
41*ab4c15feSRoss Zwisler /* taken from /sys/kernel/tracing/events/sched/sched_switch/format */
42bd4aed0eSJiong Wang struct sched_switch_args {
43bd4aed0eSJiong Wang unsigned long long pad;
443087c61eSYafang Shao char prev_comm[TASK_COMM_LEN];
45bd4aed0eSJiong Wang int prev_pid;
46bd4aed0eSJiong Wang int prev_prio;
47bd4aed0eSJiong Wang long long prev_state;
483087c61eSYafang Shao char next_comm[TASK_COMM_LEN];
49bd4aed0eSJiong Wang int next_pid;
50bd4aed0eSJiong Wang int next_prio;
51bd4aed0eSJiong Wang };
52bd4aed0eSJiong Wang
53bd4aed0eSJiong Wang SEC("tracepoint/sched/sched_switch")
oncpu(struct sched_switch_args * ctx)54bd4aed0eSJiong Wang int oncpu(struct sched_switch_args *ctx)
55bd4aed0eSJiong Wang {
56bd4aed0eSJiong Wang __u32 max_len = PERF_MAX_STACK_DEPTH * sizeof(__u64);
57bd4aed0eSJiong Wang __u32 key = 0, val = 0, *value_p;
58bd4aed0eSJiong Wang void *stack_p;
59bd4aed0eSJiong Wang
60bd4aed0eSJiong Wang value_p = bpf_map_lookup_elem(&control_map, &key);
61bd4aed0eSJiong Wang if (value_p && *value_p)
62bd4aed0eSJiong Wang return 0; /* skip if non-zero *value_p */
63bd4aed0eSJiong Wang
64bd4aed0eSJiong Wang /* The size of stackmap and stackid_hmap should be the same */
65bd4aed0eSJiong Wang key = bpf_get_stackid(ctx, &stackmap, 0);
66bd4aed0eSJiong Wang if ((int)key >= 0) {
67bd4aed0eSJiong Wang bpf_map_update_elem(&stackid_hmap, &key, &val, 0);
68bd4aed0eSJiong Wang stack_p = bpf_map_lookup_elem(&stack_amap, &key);
69bd4aed0eSJiong Wang if (stack_p)
70bd4aed0eSJiong Wang bpf_get_stack(ctx, stack_p, max_len, 0);
71bd4aed0eSJiong Wang }
72bd4aed0eSJiong Wang
73bd4aed0eSJiong Wang return 0;
74bd4aed0eSJiong Wang }
75bd4aed0eSJiong Wang
76bd4aed0eSJiong Wang char _license[] SEC("license") = "GPL";
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