1 // SPDX-License-Identifier: GPL-2.0
4 #include <subcmd/parse-options.h>
8 #include <linux/stringify.h>
16 cgroupfs_find_mountpoint(char *buf, size_t maxlen)
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;
23 fp = fopen("/proc/mounts", "r");
28 * in order to handle split hierarchy, we need to scan /proc/mounts
29 * and inspect every cgroupfs mount point to find one that has
30 * perf_event subsystem
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) {
39 if (!path_v1[0] && !strcmp(type, "cgroup")) {
41 token = strtok_r(tokens, ",", &saved_ptr);
43 while (token != NULL) {
44 if (!strcmp(token, "perf_event")) {
45 strcpy(path_v1, mountpoint);
48 token = strtok_r(NULL, ",", &saved_ptr);
52 if (!path_v2[0] && !strcmp(type, "cgroup2"))
53 strcpy(path_v2, mountpoint);
55 if (path_v1[0] && path_v2[0])
67 if (strlen(path) < maxlen) {
74 static int open_cgroup(const char *name)
76 char path[PATH_MAX + 1];
77 char mnt[PATH_MAX + 1];
81 if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
84 scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
86 fd = open(path, O_RDONLY);
88 fprintf(stderr, "no access to cgroup %s\n", path);
93 static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, const char *str)
95 struct perf_evsel *counter;
97 * check if cgrp is already defined, if so we reuse it
99 evlist__for_each_entry(evlist, counter) {
102 if (!strcmp(counter->cgrp->name, str))
103 return cgroup__get(counter->cgrp);
109 static struct cgroup *cgroup__new(const char *name)
111 struct cgroup *cgroup = zalloc(sizeof(*cgroup));
113 if (cgroup != NULL) {
114 refcount_set(&cgroup->refcnt, 1);
116 cgroup->name = strdup(name);
119 cgroup->fd = open_cgroup(name);
120 if (cgroup->fd == -1)
133 struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, const char *name)
135 struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
137 return cgroup ?: cgroup__new(name);
140 static int add_cgroup(struct perf_evlist *evlist, const char *str)
142 struct perf_evsel *counter;
143 struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
149 * find corresponding event
150 * if add cgroup N, then need to find event N
153 evlist__for_each_entry(evlist, counter) {
162 counter->cgrp = cgrp;
166 static void cgroup__delete(struct cgroup *cgroup)
169 zfree(&cgroup->name);
173 void cgroup__put(struct cgroup *cgrp)
175 if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
176 cgroup__delete(cgrp);
180 struct cgroup *cgroup__get(struct cgroup *cgroup)
183 refcount_inc(&cgroup->refcnt);
187 static void evsel__set_default_cgroup(struct perf_evsel *evsel, struct cgroup *cgroup)
189 if (evsel->cgrp == NULL)
190 evsel->cgrp = cgroup__get(cgroup);
193 void evlist__set_default_cgroup(struct perf_evlist *evlist, struct cgroup *cgroup)
195 struct perf_evsel *evsel;
197 evlist__for_each_entry(evlist, evsel)
198 evsel__set_default_cgroup(evsel, cgroup);
201 int parse_cgroups(const struct option *opt, const char *str,
202 int unset __maybe_unused)
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);
211 if (list_empty(&evlist->entries)) {
212 fprintf(stderr, "must define events before cgroups\n");
217 p = strchr(str, ',');
220 /* allow empty cgroups, i.e., skip */
222 /* termination added */
223 s = strndup(str, e - str);
226 ret = add_cgroup(evlist, s);
231 /* nr_cgroups is increased een for empty cgroups */
237 /* for the case one cgroup combine to multiple events */
239 if (nr_cgroups == 1) {
240 evlist__for_each_entry(evlist, counter) {
242 cgrp = counter->cgrp;
244 counter->cgrp = cgrp;
245 refcount_inc(&cgrp->refcnt);