1 // SPDX-License-Identifier: GPL-2.0
2 #include <subcmd/parse-options.h>
6 #include <linux/stringify.h>
7 #include <linux/zalloc.h>
17 cgroupfs_find_mountpoint(char *buf, size_t maxlen)
20 char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
21 char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
22 char *token, *saved_ptr = NULL;
24 fp = fopen("/proc/mounts", "r");
29 * in order to handle split hierarchy, we need to scan /proc/mounts
30 * and inspect every cgroupfs mount point to find one that has
31 * perf_event subsystem
36 while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
37 __stringify(PATH_MAX)"s %*d %*d\n",
38 mountpoint, type, tokens) == 3) {
40 if (!path_v1[0] && !strcmp(type, "cgroup")) {
42 token = strtok_r(tokens, ",", &saved_ptr);
44 while (token != NULL) {
45 if (!strcmp(token, "perf_event")) {
46 strcpy(path_v1, mountpoint);
49 token = strtok_r(NULL, ",", &saved_ptr);
53 if (!path_v2[0] && !strcmp(type, "cgroup2"))
54 strcpy(path_v2, mountpoint);
56 if (path_v1[0] && path_v2[0])
68 if (strlen(path) < maxlen) {
75 static int open_cgroup(const char *name)
77 char path[PATH_MAX + 1];
78 char mnt[PATH_MAX + 1];
82 if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
85 scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
87 fd = open(path, O_RDONLY);
89 fprintf(stderr, "no access to cgroup %s\n", path);
94 static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str)
96 struct evsel *counter;
98 * check if cgrp is already defined, if so we reuse it
100 evlist__for_each_entry(evlist, counter) {
103 if (!strcmp(counter->cgrp->name, str))
104 return cgroup__get(counter->cgrp);
110 static struct cgroup *cgroup__new(const char *name)
112 struct cgroup *cgroup = zalloc(sizeof(*cgroup));
114 if (cgroup != NULL) {
115 refcount_set(&cgroup->refcnt, 1);
117 cgroup->name = strdup(name);
120 cgroup->fd = open_cgroup(name);
121 if (cgroup->fd == -1)
128 zfree(&cgroup->name);
134 struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
136 struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
138 return cgroup ?: cgroup__new(name);
141 static int add_cgroup(struct evlist *evlist, const char *str)
143 struct evsel *counter;
144 struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
150 * find corresponding event
151 * if add cgroup N, then need to find event N
154 evlist__for_each_entry(evlist, counter) {
163 counter->cgrp = cgrp;
167 static void cgroup__delete(struct cgroup *cgroup)
170 zfree(&cgroup->name);
174 void cgroup__put(struct cgroup *cgrp)
176 if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
177 cgroup__delete(cgrp);
181 struct cgroup *cgroup__get(struct cgroup *cgroup)
184 refcount_inc(&cgroup->refcnt);
188 static void evsel__set_default_cgroup(struct evsel *evsel, struct cgroup *cgroup)
190 if (evsel->cgrp == NULL)
191 evsel->cgrp = cgroup__get(cgroup);
194 void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
198 evlist__for_each_entry(evlist, evsel)
199 evsel__set_default_cgroup(evsel, cgroup);
202 int parse_cgroups(const struct option *opt, const char *str,
203 int unset __maybe_unused)
205 struct evlist *evlist = *(struct evlist **)opt->value;
206 struct evsel *counter;
207 struct cgroup *cgrp = NULL;
208 const char *p, *e, *eos = str + strlen(str);
212 if (list_empty(&evlist->core.entries)) {
213 fprintf(stderr, "must define events before cgroups\n");
218 p = strchr(str, ',');
221 /* allow empty cgroups, i.e., skip */
223 /* termination added */
224 s = strndup(str, e - str);
227 ret = add_cgroup(evlist, s);
232 /* nr_cgroups is increased een for empty cgroups */
238 /* for the case one cgroup combine to multiple events */
240 if (nr_cgroups == 1) {
241 evlist__for_each_entry(evlist, counter) {
243 cgrp = counter->cgrp;
245 counter->cgrp = cgrp;
246 refcount_inc(&cgrp->refcnt);