1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
|
// SPDX-License-Identifier: GPL-2.0
#include "util.h"
#include "../perf.h"
#include <subcmd/parse-options.h>
#include "evsel.h"
#include "cgroup.h"
#include "evlist.h"
#include <linux/stringify.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
int nr_cgroups;
static int
cgroupfs_find_mountpoint(char *buf, size_t maxlen)
{
FILE *fp;
char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
char *token, *saved_ptr = NULL;
fp = fopen("/proc/mounts", "r");
if (!fp)
return -1;
/*
* in order to handle split hierarchy, we need to scan /proc/mounts
* and inspect every cgroupfs mount point to find one that has
* perf_event subsystem
*/
path_v1[0] = '\0';
path_v2[0] = '\0';
while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
__stringify(PATH_MAX)"s %*d %*d\n",
mountpoint, type, tokens) == 3) {
if (!path_v1[0] && !strcmp(type, "cgroup")) {
token = strtok_r(tokens, ",", &saved_ptr);
while (token != NULL) {
if (!strcmp(token, "perf_event")) {
strcpy(path_v1, mountpoint);
break;
}
token = strtok_r(NULL, ",", &saved_ptr);
}
}
if (!path_v2[0] && !strcmp(type, "cgroup2"))
strcpy(path_v2, mountpoint);
if (path_v1[0] && path_v2[0])
break;
}
fclose(fp);
if (path_v1[0])
path = path_v1;
else if (path_v2[0])
path = path_v2;
else
return -1;
if (strlen(path) < maxlen) {
strcpy(buf, path);
return 0;
}
return -1;
}
static int open_cgroup(const char *name)
{
char path[PATH_MAX + 1];
char mnt[PATH_MAX + 1];
int fd;
if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1))
return -1;
scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
fd = open(path, O_RDONLY);
if (fd == -1)
fprintf(stderr, "no access to cgroup %s\n", path);
return fd;
}
static struct cgroup *evlist__find_cgroup(struct perf_evlist *evlist, const char *str)
{
struct perf_evsel *counter;
/*
* check if cgrp is already defined, if so we reuse it
*/
evlist__for_each_entry(evlist, counter) {
if (!counter->cgrp)
continue;
if (!strcmp(counter->cgrp->name, str))
return cgroup__get(counter->cgrp);
}
return NULL;
}
static struct cgroup *cgroup__new(const char *name)
{
struct cgroup *cgroup = zalloc(sizeof(*cgroup));
if (cgroup != NULL) {
refcount_set(&cgroup->refcnt, 1);
cgroup->name = strdup(name);
if (!cgroup->name)
goto out_err;
cgroup->fd = open_cgroup(name);
if (cgroup->fd == -1)
goto out_free_name;
}
return cgroup;
out_free_name:
free(cgroup->name);
out_err:
free(cgroup);
return NULL;
}
struct cgroup *evlist__findnew_cgroup(struct perf_evlist *evlist, const char *name)
{
struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
return cgroup ?: cgroup__new(name);
}
static int add_cgroup(struct perf_evlist *evlist, const char *str)
{
struct perf_evsel *counter;
struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
int n;
if (!cgrp)
return -1;
/*
* find corresponding event
* if add cgroup N, then need to find event N
*/
n = 0;
evlist__for_each_entry(evlist, counter) {
if (n == nr_cgroups)
goto found;
n++;
}
cgroup__put(cgrp);
return -1;
found:
counter->cgrp = cgrp;
return 0;
}
static void cgroup__delete(struct cgroup *cgroup)
{
close(cgroup->fd);
zfree(&cgroup->name);
free(cgroup);
}
void cgroup__put(struct cgroup *cgrp)
{
if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
cgroup__delete(cgrp);
}
}
struct cgroup *cgroup__get(struct cgroup *cgroup)
{
if (cgroup)
refcount_inc(&cgroup->refcnt);
return cgroup;
}
static void evsel__set_default_cgroup(struct perf_evsel *evsel, struct cgroup *cgroup)
{
if (evsel->cgrp == NULL)
evsel->cgrp = cgroup__get(cgroup);
}
void evlist__set_default_cgroup(struct perf_evlist *evlist, struct cgroup *cgroup)
{
struct perf_evsel *evsel;
evlist__for_each_entry(evlist, evsel)
evsel__set_default_cgroup(evsel, cgroup);
}
int parse_cgroups(const struct option *opt, const char *str,
int unset __maybe_unused)
{
struct perf_evlist *evlist = *(struct perf_evlist **)opt->value;
struct perf_evsel *counter;
struct cgroup *cgrp = NULL;
const char *p, *e, *eos = str + strlen(str);
char *s;
int ret, i;
if (list_empty(&evlist->entries)) {
fprintf(stderr, "must define events before cgroups\n");
return -1;
}
for (;;) {
p = strchr(str, ',');
e = p ? p : eos;
/* allow empty cgroups, i.e., skip */
if (e - str) {
/* termination added */
s = strndup(str, e - str);
if (!s)
return -1;
ret = add_cgroup(evlist, s);
free(s);
if (ret)
return -1;
}
/* nr_cgroups is increased een for empty cgroups */
nr_cgroups++;
if (!p)
break;
str = p+1;
}
/* for the case one cgroup combine to multiple events */
i = 0;
if (nr_cgroups == 1) {
evlist__for_each_entry(evlist, counter) {
if (i == 0)
cgrp = counter->cgrp;
else {
counter->cgrp = cgrp;
refcount_inc(&cgrp->refcnt);
}
i++;
}
}
return 0;
}
|
