1 #include "util.h"
2 #include "../perf.h"
3 #include "parse-options.h"
4 #include "evsel.h"
5 #include "cgroup.h"
6 #include "debugfs.h" /* MAX_PATH, STR() */
7 #include "evlist.h"
8
9 int nr_cgroups;
10
11 static int
cgroupfs_find_mountpoint(char * buf,size_t maxlen)12 cgroupfs_find_mountpoint(char *buf, size_t maxlen)
13 {
14 FILE *fp;
15 char mountpoint[MAX_PATH+1], tokens[MAX_PATH+1], type[MAX_PATH+1];
16 char *token, *saved_ptr = NULL;
17 int found = 0;
18
19 fp = fopen("/proc/mounts", "r");
20 if (!fp)
21 return -1;
22
23 /*
24 * in order to handle split hierarchy, we need to scan /proc/mounts
25 * and inspect every cgroupfs mount point to find one that has
26 * perf_event subsystem
27 */
28 while (fscanf(fp, "%*s %"STR(MAX_PATH)"s %"STR(MAX_PATH)"s %"
29 STR(MAX_PATH)"s %*d %*d\n",
30 mountpoint, type, tokens) == 3) {
31
32 if (!strcmp(type, "cgroup")) {
33
34 token = strtok_r(tokens, ",", &saved_ptr);
35
36 while (token != NULL) {
37 if (!strcmp(token, "perf_event")) {
38 found = 1;
39 break;
40 }
41 token = strtok_r(NULL, ",", &saved_ptr);
42 }
43 }
44 if (found)
45 break;
46 }
47 fclose(fp);
48 if (!found)
49 return -1;
50
51 if (strlen(mountpoint) < maxlen) {
52 strcpy(buf, mountpoint);
53 return 0;
54 }
55 return -1;
56 }
57
open_cgroup(char * name)58 static int open_cgroup(char *name)
59 {
60 char path[MAX_PATH+1];
61 char mnt[MAX_PATH+1];
62 int fd;
63
64
65 if (cgroupfs_find_mountpoint(mnt, MAX_PATH+1))
66 return -1;
67
68 snprintf(path, MAX_PATH, "%s/%s", mnt, name);
69
70 fd = open(path, O_RDONLY);
71 if (fd == -1)
72 fprintf(stderr, "no access to cgroup %s\n", path);
73
74 return fd;
75 }
76
add_cgroup(struct perf_evlist * evlist,char * str)77 static int add_cgroup(struct perf_evlist *evlist, char *str)
78 {
79 struct perf_evsel *counter;
80 struct cgroup_sel *cgrp = NULL;
81 int n;
82 /*
83 * check if cgrp is already defined, if so we reuse it
84 */
85 list_for_each_entry(counter, &evlist->entries, node) {
86 cgrp = counter->cgrp;
87 if (!cgrp)
88 continue;
89 if (!strcmp(cgrp->name, str))
90 break;
91
92 cgrp = NULL;
93 }
94
95 if (!cgrp) {
96 cgrp = zalloc(sizeof(*cgrp));
97 if (!cgrp)
98 return -1;
99
100 cgrp->name = str;
101
102 cgrp->fd = open_cgroup(str);
103 if (cgrp->fd == -1) {
104 free(cgrp);
105 return -1;
106 }
107 }
108
109 /*
110 * find corresponding event
111 * if add cgroup N, then need to find event N
112 */
113 n = 0;
114 list_for_each_entry(counter, &evlist->entries, node) {
115 if (n == nr_cgroups)
116 goto found;
117 n++;
118 }
119 if (cgrp->refcnt == 0)
120 free(cgrp);
121
122 return -1;
123 found:
124 cgrp->refcnt++;
125 counter->cgrp = cgrp;
126 return 0;
127 }
128
close_cgroup(struct cgroup_sel * cgrp)129 void close_cgroup(struct cgroup_sel *cgrp)
130 {
131 if (!cgrp)
132 return;
133
134 /* XXX: not reentrant */
135 if (--cgrp->refcnt == 0) {
136 close(cgrp->fd);
137 free(cgrp->name);
138 free(cgrp);
139 }
140 }
141
parse_cgroups(const struct option * opt __used,const char * str,int unset __used)142 int parse_cgroups(const struct option *opt __used, const char *str,
143 int unset __used)
144 {
145 struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
146 const char *p, *e, *eos = str + strlen(str);
147 char *s;
148 int ret;
149
150 if (list_empty(&evlist->entries)) {
151 fprintf(stderr, "must define events before cgroups\n");
152 return -1;
153 }
154
155 for (;;) {
156 p = strchr(str, ',');
157 e = p ? p : eos;
158
159 /* allow empty cgroups, i.e., skip */
160 if (e - str) {
161 /* termination added */
162 s = strndup(str, e - str);
163 if (!s)
164 return -1;
165 ret = add_cgroup(evlist, s);
166 if (ret) {
167 free(s);
168 return -1;
169 }
170 }
171 /* nr_cgroups is increased een for empty cgroups */
172 nr_cgroups++;
173 if (!p)
174 break;
175 str = p+1;
176 }
177 return 0;
178 }
179