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a6ffe7b9 AS |
1 | /* Copyright (c) 2016 Facebook |
2 | * | |
3 | * This program is free software; you can redistribute it and/or | |
4 | * modify it under the terms of version 2 of the GNU General Public | |
5 | * License as published by the Free Software Foundation. | |
6 | */ | |
7 | #include <uapi/linux/bpf.h> | |
a6ffe7b9 AS |
8 | #include <uapi/linux/ptrace.h> |
9 | #include <uapi/linux/perf_event.h> | |
10 | #include <linux/version.h> | |
11 | #include <linux/sched.h> | |
03421a92 YS |
12 | #include <bpf/bpf_helpers.h> |
13 | #include <bpf/bpf_tracing.h> | |
a6ffe7b9 | 14 | |
e4d9c232 IL |
15 | #define _(P) \ |
16 | ({ \ | |
17 | typeof(P) val; \ | |
18 | bpf_probe_read_kernel(&val, sizeof(val), &(P)); \ | |
19 | val; \ | |
20 | }) | |
a6ffe7b9 AS |
21 | |
22 | #define MINBLOCK_US 1 | |
d1bf7c4d | 23 | #define MAX_ENTRIES 10000 |
a6ffe7b9 AS |
24 | |
25 | struct key_t { | |
26 | char waker[TASK_COMM_LEN]; | |
27 | char target[TASK_COMM_LEN]; | |
28 | u32 wret; | |
29 | u32 tret; | |
30 | }; | |
31 | ||
f0c328f8 DL |
32 | struct { |
33 | __uint(type, BPF_MAP_TYPE_HASH); | |
34 | __type(key, struct key_t); | |
35 | __type(value, u64); | |
d1bf7c4d | 36 | __uint(max_entries, MAX_ENTRIES); |
f0c328f8 | 37 | } counts SEC(".maps"); |
a6ffe7b9 | 38 | |
f0c328f8 DL |
39 | struct { |
40 | __uint(type, BPF_MAP_TYPE_HASH); | |
41 | __type(key, u32); | |
42 | __type(value, u64); | |
d1bf7c4d | 43 | __uint(max_entries, MAX_ENTRIES); |
f0c328f8 | 44 | } start SEC(".maps"); |
a6ffe7b9 AS |
45 | |
46 | struct wokeby_t { | |
47 | char name[TASK_COMM_LEN]; | |
48 | u32 ret; | |
49 | }; | |
50 | ||
f0c328f8 DL |
51 | struct { |
52 | __uint(type, BPF_MAP_TYPE_HASH); | |
53 | __type(key, u32); | |
54 | __type(value, struct wokeby_t); | |
d1bf7c4d | 55 | __uint(max_entries, MAX_ENTRIES); |
f0c328f8 | 56 | } wokeby SEC(".maps"); |
a6ffe7b9 | 57 | |
f0c328f8 DL |
58 | struct { |
59 | __uint(type, BPF_MAP_TYPE_STACK_TRACE); | |
60 | __uint(key_size, sizeof(u32)); | |
61 | __uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64)); | |
d1bf7c4d | 62 | __uint(max_entries, MAX_ENTRIES); |
f0c328f8 | 63 | } stackmap SEC(".maps"); |
a6ffe7b9 AS |
64 | |
65 | #define STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP) | |
66 | ||
67 | SEC("kprobe/try_to_wake_up") | |
68 | int waker(struct pt_regs *ctx) | |
69 | { | |
70 | struct task_struct *p = (void *) PT_REGS_PARM1(ctx); | |
02413cab | 71 | struct wokeby_t woke; |
a6ffe7b9 AS |
72 | u32 pid; |
73 | ||
74 | pid = _(p->pid); | |
75 | ||
76 | bpf_get_current_comm(&woke.name, sizeof(woke.name)); | |
77 | woke.ret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS); | |
78 | ||
79 | bpf_map_update_elem(&wokeby, &pid, &woke, BPF_ANY); | |
80 | return 0; | |
81 | } | |
82 | ||
3c9b1644 | 83 | static inline int update_counts(void *ctx, u32 pid, u64 delta) |
a6ffe7b9 | 84 | { |
a6ffe7b9 AS |
85 | struct wokeby_t *woke; |
86 | u64 zero = 0, *val; | |
02413cab | 87 | struct key_t key; |
a6ffe7b9 | 88 | |
02413cab | 89 | __builtin_memset(&key.waker, 0, sizeof(key.waker)); |
a6ffe7b9 AS |
90 | bpf_get_current_comm(&key.target, sizeof(key.target)); |
91 | key.tret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS); | |
02413cab | 92 | key.wret = 0; |
a6ffe7b9 AS |
93 | |
94 | woke = bpf_map_lookup_elem(&wokeby, &pid); | |
95 | if (woke) { | |
96 | key.wret = woke->ret; | |
02413cab | 97 | __builtin_memcpy(&key.waker, woke->name, sizeof(key.waker)); |
a6ffe7b9 AS |
98 | bpf_map_delete_elem(&wokeby, &pid); |
99 | } | |
100 | ||
101 | val = bpf_map_lookup_elem(&counts, &key); | |
102 | if (!val) { | |
103 | bpf_map_update_elem(&counts, &key, &zero, BPF_NOEXIST); | |
104 | val = bpf_map_lookup_elem(&counts, &key); | |
105 | if (!val) | |
106 | return 0; | |
107 | } | |
108 | (*val) += delta; | |
109 | return 0; | |
110 | } | |
111 | ||
3c9b1644 AS |
112 | #if 1 |
113 | /* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */ | |
114 | struct sched_switch_args { | |
115 | unsigned long long pad; | |
d068144d | 116 | char prev_comm[TASK_COMM_LEN]; |
3c9b1644 AS |
117 | int prev_pid; |
118 | int prev_prio; | |
119 | long long prev_state; | |
d068144d | 120 | char next_comm[TASK_COMM_LEN]; |
3c9b1644 AS |
121 | int next_pid; |
122 | int next_prio; | |
123 | }; | |
124 | SEC("tracepoint/sched/sched_switch") | |
125 | int oncpu(struct sched_switch_args *ctx) | |
126 | { | |
127 | /* record previous thread sleep time */ | |
128 | u32 pid = ctx->prev_pid; | |
129 | #else | |
a6ffe7b9 AS |
130 | SEC("kprobe/finish_task_switch") |
131 | int oncpu(struct pt_regs *ctx) | |
132 | { | |
133 | struct task_struct *p = (void *) PT_REGS_PARM1(ctx); | |
3c9b1644 AS |
134 | /* record previous thread sleep time */ |
135 | u32 pid = _(p->pid); | |
136 | #endif | |
a6ffe7b9 | 137 | u64 delta, ts, *tsp; |
a6ffe7b9 | 138 | |
a6ffe7b9 AS |
139 | ts = bpf_ktime_get_ns(); |
140 | bpf_map_update_elem(&start, &pid, &ts, BPF_ANY); | |
141 | ||
142 | /* calculate current thread's delta time */ | |
143 | pid = bpf_get_current_pid_tgid(); | |
144 | tsp = bpf_map_lookup_elem(&start, &pid); | |
145 | if (!tsp) | |
146 | /* missed start or filtered */ | |
147 | return 0; | |
148 | ||
149 | delta = bpf_ktime_get_ns() - *tsp; | |
150 | bpf_map_delete_elem(&start, &pid); | |
151 | delta = delta / 1000; | |
152 | if (delta < MINBLOCK_US) | |
153 | return 0; | |
154 | ||
155 | return update_counts(ctx, pid, delta); | |
156 | } | |
157 | char _license[] SEC("license") = "GPL"; | |
158 | u32 _version SEC("version") = LINUX_VERSION_CODE; |