1 #include "util.h"
2 #include "../perf.h"
3 #include <subcmd/parse-options.h>
4 #include "evsel.h"
5 #include "cgroup.h"
6 #include "evlist.h"
7
8 int nr_cgroups;
9
10 static int
cgroupfs_find_mountpoint(char * buf,size_t maxlen)11 cgroupfs_find_mountpoint(char *buf, size_t maxlen)
12 {
13 FILE *fp;
14 char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
15 char *token, *saved_ptr = NULL;
16 int found = 0;
17
18 fp = fopen("/proc/mounts", "r");
19 if (!fp)
20 return -1;
21
22 /*
23 * in order to handle split hierarchy, we need to scan /proc/mounts
24 * and inspect every cgroupfs mount point to find one that has
25 * perf_event subsystem
26 */
27 while (fscanf(fp, "%*s %"STR(PATH_MAX)"s %"STR(PATH_MAX)"s %"
28 STR(PATH_MAX)"s %*d %*d\n",
29 mountpoint, type, tokens) == 3) {
30
31 if (!strcmp(type, "cgroup")) {
32
33 token = strtok_r(tokens, ",", &saved_ptr);
34
35 while (token != NULL) {
36 if (!strcmp(token, "perf_event")) {
37 found = 1;
38 break;
39 }
40 token = strtok_r(NULL, ",", &saved_ptr);
41 }
42 }
43 if (found)
44 break;
45 }
46 fclose(fp);
47 if (!found)
48 return -1;
49
50 if (strlen(mountpoint) < maxlen) {
51 strcpy(buf, mountpoint);
52 return 0;
53 }
54 return -1;
55 }
56
open_cgroup(char * name)57 static int open_cgroup(char *name)
58 {
59 char path[PATH_MAX + 1];
60 char mnt[PATH_MAX + 1];
61 int fd;
62
63
64 if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
65 return -1;
66
67 snprintf(path, PATH_MAX, "%s/%s", mnt, name);
68
69 fd = open(path, O_RDONLY);
70 if (fd == -1)
71 fprintf(stderr, "no access to cgroup %s\n", path);
72
73 return fd;
74 }
75
add_cgroup(struct perf_evlist * evlist,char * str)76 static int add_cgroup(struct perf_evlist *evlist, char *str)
77 {
78 struct perf_evsel *counter;
79 struct cgroup_sel *cgrp = NULL;
80 int n;
81 /*
82 * check if cgrp is already defined, if so we reuse it
83 */
84 evlist__for_each_entry(evlist, counter) {
85 cgrp = counter->cgrp;
86 if (!cgrp)
87 continue;
88 if (!strcmp(cgrp->name, str))
89 break;
90
91 cgrp = NULL;
92 }
93
94 if (!cgrp) {
95 cgrp = zalloc(sizeof(*cgrp));
96 if (!cgrp)
97 return -1;
98
99 cgrp->name = str;
100
101 cgrp->fd = open_cgroup(str);
102 if (cgrp->fd == -1) {
103 free(cgrp);
104 return -1;
105 }
106 }
107
108 /*
109 * find corresponding event
110 * if add cgroup N, then need to find event N
111 */
112 n = 0;
113 evlist__for_each_entry(evlist, counter) {
114 if (n == nr_cgroups)
115 goto found;
116 n++;
117 }
118 if (atomic_read(&cgrp->refcnt) == 0)
119 free(cgrp);
120
121 return -1;
122 found:
123 atomic_inc(&cgrp->refcnt);
124 counter->cgrp = cgrp;
125 return 0;
126 }
127
close_cgroup(struct cgroup_sel * cgrp)128 void close_cgroup(struct cgroup_sel *cgrp)
129 {
130 if (cgrp && atomic_dec_and_test(&cgrp->refcnt)) {
131 close(cgrp->fd);
132 zfree(&cgrp->name);
133 free(cgrp);
134 }
135 }
136
parse_cgroups(const struct option * opt __maybe_unused,const char * str,int unset __maybe_unused)137 int parse_cgroups(const struct option *opt __maybe_unused, const char *str,
138 int unset __maybe_unused)
139 {
140 struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
141 const char *p, *e, *eos = str + strlen(str);
142 char *s;
143 int ret;
144
145 if (list_empty(&evlist->entries)) {
146 fprintf(stderr, "must define events before cgroups\n");
147 return -1;
148 }
149
150 for (;;) {
151 p = strchr(str, ',');
152 e = p ? p : eos;
153
154 /* allow empty cgroups, i.e., skip */
155 if (e - str) {
156 /* termination added */
157 s = strndup(str, e - str);
158 if (!s)
159 return -1;
160 ret = add_cgroup(evlist, s);
161 if (ret) {
162 free(s);
163 return -1;
164 }
165 }
166 /* nr_cgroups is increased een for empty cgroups */
167 nr_cgroups++;
168 if (!p)
169 break;
170 str = p+1;
171 }
172 return 0;
173 }
174