1 // SPDX-License-Identifier: GPL-2.0
2
3 /* Copyright (c) 2021 Facebook */
4 /* Copyright (c) 2021 Google */
5
6 #include <assert.h>
7 #include <limits.h>
8 #include <unistd.h>
9 #include <sys/file.h>
10 #include <sys/time.h>
11 #include <sys/resource.h>
12 #include <linux/err.h>
13 #include <linux/zalloc.h>
14 #include <linux/perf_event.h>
15 #include <api/fs/fs.h>
16 #include <perf/bpf_perf.h>
17
18 #include "affinity.h"
19 #include "bpf_counter.h"
20 #include "cgroup.h"
21 #include "counts.h"
22 #include "debug.h"
23 #include "evsel.h"
24 #include "evlist.h"
25 #include "target.h"
26 #include "cpumap.h"
27 #include "thread_map.h"
28
29 #include "bpf_skel/bperf_cgroup.skel.h"
30
31 static struct perf_event_attr cgrp_switch_attr = {
32 .type = PERF_TYPE_SOFTWARE,
33 .config = PERF_COUNT_SW_CGROUP_SWITCHES,
34 .size = sizeof(cgrp_switch_attr),
35 .sample_period = 1,
36 .disabled = 1,
37 };
38
39 static struct evsel *cgrp_switch;
40 static struct bperf_cgroup_bpf *skel;
41
42 #define FD(evt, cpu) (*(int *)xyarray__entry(evt->core.fd, cpu, 0))
43
bperf_load_program(struct evlist * evlist)44 static int bperf_load_program(struct evlist *evlist)
45 {
46 struct bpf_link *link;
47 struct evsel *evsel;
48 struct cgroup *cgrp, *leader_cgrp;
49 int i, j;
50 struct perf_cpu cpu;
51 int total_cpus = cpu__max_cpu().cpu;
52 int map_size, map_fd;
53 int prog_fd, err;
54
55 skel = bperf_cgroup_bpf__open();
56 if (!skel) {
57 pr_err("Failed to open cgroup skeleton\n");
58 return -1;
59 }
60
61 skel->rodata->num_cpus = total_cpus;
62 skel->rodata->num_events = evlist->core.nr_entries / nr_cgroups;
63
64 BUG_ON(evlist->core.nr_entries % nr_cgroups != 0);
65
66 /* we need one copy of events per cpu for reading */
67 map_size = total_cpus * evlist->core.nr_entries / nr_cgroups;
68 bpf_map__set_max_entries(skel->maps.events, map_size);
69 bpf_map__set_max_entries(skel->maps.cgrp_idx, nr_cgroups);
70 /* previous result is saved in a per-cpu array */
71 map_size = evlist->core.nr_entries / nr_cgroups;
72 bpf_map__set_max_entries(skel->maps.prev_readings, map_size);
73 /* cgroup result needs all events (per-cpu) */
74 map_size = evlist->core.nr_entries;
75 bpf_map__set_max_entries(skel->maps.cgrp_readings, map_size);
76
77 set_max_rlimit();
78
79 err = bperf_cgroup_bpf__load(skel);
80 if (err) {
81 pr_err("Failed to load cgroup skeleton\n");
82 goto out;
83 }
84
85 if (cgroup_is_v2("perf_event") > 0)
86 skel->bss->use_cgroup_v2 = 1;
87
88 err = -1;
89
90 cgrp_switch = evsel__new(&cgrp_switch_attr);
91 if (evsel__open_per_cpu(cgrp_switch, evlist->core.all_cpus, -1) < 0) {
92 pr_err("Failed to open cgroup switches event\n");
93 goto out;
94 }
95
96 perf_cpu_map__for_each_cpu(cpu, i, evlist->core.all_cpus) {
97 link = bpf_program__attach_perf_event(skel->progs.on_cgrp_switch,
98 FD(cgrp_switch, i));
99 if (IS_ERR(link)) {
100 pr_err("Failed to attach cgroup program\n");
101 err = PTR_ERR(link);
102 goto out;
103 }
104 }
105
106 /*
107 * Update cgrp_idx map from cgroup-id to event index.
108 */
109 cgrp = NULL;
110 i = 0;
111
112 evlist__for_each_entry(evlist, evsel) {
113 if (cgrp == NULL || evsel->cgrp == leader_cgrp) {
114 leader_cgrp = evsel->cgrp;
115 evsel->cgrp = NULL;
116
117 /* open single copy of the events w/o cgroup */
118 err = evsel__open_per_cpu(evsel, evsel->core.cpus, -1);
119 if (err) {
120 pr_err("Failed to open first cgroup events\n");
121 goto out;
122 }
123
124 map_fd = bpf_map__fd(skel->maps.events);
125 perf_cpu_map__for_each_cpu(cpu, j, evsel->core.cpus) {
126 int fd = FD(evsel, j);
127 __u32 idx = evsel->core.idx * total_cpus + cpu.cpu;
128
129 err = bpf_map_update_elem(map_fd, &idx, &fd,
130 BPF_ANY);
131 if (err < 0) {
132 pr_err("Failed to update perf_event fd\n");
133 goto out;
134 }
135 }
136
137 evsel->cgrp = leader_cgrp;
138 }
139 evsel->supported = true;
140
141 if (evsel->cgrp == cgrp)
142 continue;
143
144 cgrp = evsel->cgrp;
145
146 if (read_cgroup_id(cgrp) < 0) {
147 pr_err("Failed to get cgroup id\n");
148 err = -1;
149 goto out;
150 }
151
152 map_fd = bpf_map__fd(skel->maps.cgrp_idx);
153 err = bpf_map_update_elem(map_fd, &cgrp->id, &i, BPF_ANY);
154 if (err < 0) {
155 pr_err("Failed to update cgroup index map\n");
156 goto out;
157 }
158
159 i++;
160 }
161
162 /*
163 * bperf uses BPF_PROG_TEST_RUN to get accurate reading. Check
164 * whether the kernel support it
165 */
166 prog_fd = bpf_program__fd(skel->progs.trigger_read);
167 err = bperf_trigger_reading(prog_fd, 0);
168 if (err) {
169 pr_warning("The kernel does not support test_run for raw_tp BPF programs.\n"
170 "Therefore, --for-each-cgroup might show inaccurate readings\n");
171 err = 0;
172 }
173
174 out:
175 return err;
176 }
177
bperf_cgrp__load(struct evsel * evsel,struct target * target __maybe_unused)178 static int bperf_cgrp__load(struct evsel *evsel,
179 struct target *target __maybe_unused)
180 {
181 static bool bperf_loaded = false;
182
183 evsel->bperf_leader_prog_fd = -1;
184 evsel->bperf_leader_link_fd = -1;
185
186 if (!bperf_loaded && bperf_load_program(evsel->evlist))
187 return -1;
188
189 bperf_loaded = true;
190 /* just to bypass bpf_counter_skip() */
191 evsel->follower_skel = (struct bperf_follower_bpf *)skel;
192
193 return 0;
194 }
195
bperf_cgrp__install_pe(struct evsel * evsel __maybe_unused,int cpu __maybe_unused,int fd __maybe_unused)196 static int bperf_cgrp__install_pe(struct evsel *evsel __maybe_unused,
197 int cpu __maybe_unused, int fd __maybe_unused)
198 {
199 /* nothing to do */
200 return 0;
201 }
202
203 /*
204 * trigger the leader prog on each cpu, so the cgrp_reading map could get
205 * the latest results.
206 */
bperf_cgrp__sync_counters(struct evlist * evlist)207 static int bperf_cgrp__sync_counters(struct evlist *evlist)
208 {
209 struct perf_cpu cpu;
210 int idx;
211 int prog_fd = bpf_program__fd(skel->progs.trigger_read);
212
213 perf_cpu_map__for_each_cpu(cpu, idx, evlist->core.all_cpus)
214 bperf_trigger_reading(prog_fd, cpu.cpu);
215
216 return 0;
217 }
218
bperf_cgrp__enable(struct evsel * evsel)219 static int bperf_cgrp__enable(struct evsel *evsel)
220 {
221 if (evsel->core.idx)
222 return 0;
223
224 bperf_cgrp__sync_counters(evsel->evlist);
225
226 skel->bss->enabled = 1;
227 return 0;
228 }
229
bperf_cgrp__disable(struct evsel * evsel)230 static int bperf_cgrp__disable(struct evsel *evsel)
231 {
232 if (evsel->core.idx)
233 return 0;
234
235 bperf_cgrp__sync_counters(evsel->evlist);
236
237 skel->bss->enabled = 0;
238 return 0;
239 }
240
bperf_cgrp__read(struct evsel * evsel)241 static int bperf_cgrp__read(struct evsel *evsel)
242 {
243 struct evlist *evlist = evsel->evlist;
244 int total_cpus = cpu__max_cpu().cpu;
245 struct perf_counts_values *counts;
246 struct bpf_perf_event_value *values;
247 int reading_map_fd, err = 0;
248
249 if (evsel->core.idx)
250 return 0;
251
252 bperf_cgrp__sync_counters(evsel->evlist);
253
254 values = calloc(total_cpus, sizeof(*values));
255 if (values == NULL)
256 return -ENOMEM;
257
258 reading_map_fd = bpf_map__fd(skel->maps.cgrp_readings);
259
260 evlist__for_each_entry(evlist, evsel) {
261 __u32 idx = evsel->core.idx;
262 int i;
263 struct perf_cpu cpu;
264
265 err = bpf_map_lookup_elem(reading_map_fd, &idx, values);
266 if (err) {
267 pr_err("bpf map lookup failed: idx=%u, event=%s, cgrp=%s\n",
268 idx, evsel__name(evsel), evsel->cgrp->name);
269 goto out;
270 }
271
272 perf_cpu_map__for_each_cpu(cpu, i, evsel->core.cpus) {
273 counts = perf_counts(evsel->counts, i, 0);
274 counts->val = values[cpu.cpu].counter;
275 counts->ena = values[cpu.cpu].enabled;
276 counts->run = values[cpu.cpu].running;
277 }
278 }
279
280 out:
281 free(values);
282 return err;
283 }
284
bperf_cgrp__destroy(struct evsel * evsel)285 static int bperf_cgrp__destroy(struct evsel *evsel)
286 {
287 if (evsel->core.idx)
288 return 0;
289
290 bperf_cgroup_bpf__destroy(skel);
291 evsel__delete(cgrp_switch); // it'll destroy on_switch progs too
292
293 return 0;
294 }
295
296 struct bpf_counter_ops bperf_cgrp_ops = {
297 .load = bperf_cgrp__load,
298 .enable = bperf_cgrp__enable,
299 .disable = bperf_cgrp__disable,
300 .read = bperf_cgrp__read,
301 .install_pe = bperf_cgrp__install_pe,
302 .destroy = bperf_cgrp__destroy,
303 };
304
