1
2#include "util.h"
3#include "../perf.h"
4#include <subcmd/parse-options.h>
5#include "evsel.h"
6#include "cgroup.h"
7#include "evlist.h"
8#include <linux/stringify.h>
9#include <sys/types.h>
10#include <sys/stat.h>
11#include <fcntl.h>
12
13int nr_cgroups;
14
15static int
16cgroupfs_find_mountpoint(char *buf, size_t maxlen)
17{
18 FILE *fp;
19 char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
20 char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
21 char *token, *saved_ptr = NULL;
22
23 fp = fopen("/proc/mounts", "r");
24 if (!fp)
25 return -1;
26
27
28
29
30
31
32 path_v1[0] = '\0';
33 path_v2[0] = '\0';
34
35 while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
36 __stringify(PATH_MAX)"s %*d %*d\n",
37 mountpoint, type, tokens) == 3) {
38
39 if (!path_v1[0] && !strcmp(type, "cgroup")) {
40
41 token = strtok_r(tokens, ",", &saved_ptr);
42
43 while (token != NULL) {
44 if (!strcmp(token, "perf_event")) {
45 strcpy(path_v1, mountpoint);
46 break;
47 }
48 token = strtok_r(NULL, ",", &saved_ptr);
49 }
50 }
51
52 if (!path_v2[0] && !strcmp(type, "cgroup2"))
53 strcpy(path_v2, mountpoint);
54
55 if (path_v1[0] && path_v2[0])
56 break;
57 }
58 fclose(fp);
59
60 if (path_v1[0])
61 path = path_v1;
62 else if (path_v2[0])
63 path = path_v2;
64 else
65 return -1;
66
67 if (strlen(path) < maxlen) {
68 strcpy(buf, path);
69 return 0;
70 }
71 return -1;
72}
73
74static int open_cgroup(const char *name)
75{
76 char path[PATH_MAX + 1];
77 char mnt[PATH_MAX + 1];
78 int fd;
79
80
81 if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
82 return -1;
83
84 scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
85
86 fd = open(path, O_RDONLY);
87 if (fd == -1)
88 fprintf(stderr, "no access to cgroup %s\n", path);
89
90 return fd;
91}
92
93static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, const char *str)
94{
95 struct perf_evsel *counter;
96
97
98
99 evlist__for_each_entry(evlist, counter) {
100 if (!counter->cgrp)
101 continue;
102 if (!strcmp(counter->cgrp->name, str))
103 return cgroup__get(counter->cgrp);
104 }
105
106 return NULL;
107}
108
109static struct cgroup *cgroup__new(const char *name)
110{
111 struct cgroup *cgroup = zalloc(sizeof(*cgroup));
112
113 if (cgroup != NULL) {
114 refcount_set(&cgroup->refcnt, 1);
115
116 cgroup->name = strdup(name);
117 if (!cgroup->name)
118 goto out_err;
119 cgroup->fd = open_cgroup(name);
120 if (cgroup->fd == -1)
121 goto out_free_name;
122 }
123
124 return cgroup;
125
126out_free_name:
127 free(cgroup->name);
128out_err:
129 free(cgroup);
130 return NULL;
131}
132
133struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, const char *name)
134{
135 struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
136
137 return cgroup ?: cgroup__new(name);
138}
139
140static int add_cgroup(struct perf_evlist *evlist, const char *str)
141{
142 struct perf_evsel *counter;
143 struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
144 int n;
145
146 if (!cgrp)
147 return -1;
148
149
150
151
152 n = 0;
153 evlist__for_each_entry(evlist, counter) {
154 if (n == nr_cgroups)
155 goto found;
156 n++;
157 }
158
159 cgroup__put(cgrp);
160 return -1;
161found:
162 counter->cgrp = cgrp;
163 return 0;
164}
165
166static void cgroup__delete(struct cgroup *cgroup)
167{
168 close(cgroup->fd);
169 zfree(&cgroup->name);
170 free(cgroup);
171}
172
173void cgroup__put(struct cgroup *cgrp)
174{
175 if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
176 cgroup__delete(cgrp);
177 }
178}
179
180struct cgroup *cgroup__get(struct cgroup *cgroup)
181{
182 if (cgroup)
183 refcount_inc(&cgroup->refcnt);
184 return cgroup;
185}
186
187static void evsel__set_default_cgroup(struct perf_evsel *evsel, struct cgroup *cgroup)
188{
189 if (evsel->cgrp == NULL)
190 evsel->cgrp = cgroup__get(cgroup);
191}
192
193void evlist__set_default_cgroup(struct perf_evlist *evlist, struct cgroup *cgroup)
194{
195 struct perf_evsel *evsel;
196
197 evlist__for_each_entry(evlist, evsel)
198 evsel__set_default_cgroup(evsel, cgroup);
199}
200
201int parse_cgroups(const struct option *opt, const char *str,
202 int unset __maybe_unused)
203{
204 struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
205 struct perf_evsel *counter;
206 struct cgroup *cgrp = NULL;
207 const char *p, *e, *eos = str + strlen(str);
208 char *s;
209 int ret, i;
210
211 if (list_empty(&evlist->entries)) {
212 fprintf(stderr, "must define events before cgroups\n");
213 return -1;
214 }
215
216 for (;;) {
217 p = strchr(str, ',');
218 e = p ? p : eos;
219
220
221 if (e - str) {
222
223 s = strndup(str, e - str);
224 if (!s)
225 return -1;
226 ret = add_cgroup(evlist, s);
227 free(s);
228 if (ret)
229 return -1;
230 }
231
232 nr_cgroups++;
233 if (!p)
234 break;
235 str = p+1;
236 }
237
238 i = 0;
239 if (nr_cgroups == 1) {
240 evlist__for_each_entry(evlist, counter) {
241 if (i == 0)
242 cgrp = counter->cgrp;
243 else {
244 counter->cgrp = cgrp;
245 refcount_inc(&cgrp->refcnt);
246 }
247 i++;
248 }
249 }
250 return 0;
251}
252