summaryrefslogtreecommitdiffstats
path: root/tools/perf/util/cgroup.c
blob: 5bc9d3b01bd9200ab84349d27924598ae64f453b (plain)
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
// SPDX-License-Identifier: GPL-2.0
#include <subcmd/parse-options.h>
#include "evsel.h"
#include "cgroup.h"
#include "evlist.h"
#include <linux/zalloc.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <api/fs/fs.h>

int nr_cgroups;

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, "perf_event"))
		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 evlist *evlist, const char *str)
{
	struct 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:
	zfree(&cgroup->name);
out_err:
	free(cgroup);
	return NULL;
}

struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
{
	struct cgroup *cgroup = evlist__find_cgroup(evlist, name);

	return cgroup ?: cgroup__new(name);
}

static int add_cgroup(struct evlist *evlist, const char *str)
{
	struct 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 evsel *evsel, struct cgroup *cgroup)
{
	if (evsel->cgrp == NULL)
		evsel->cgrp = cgroup__get(cgroup);
}

void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
{
	struct 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 evlist *evlist = *(struct evlist **)opt->value;
	struct evsel *counter;
	struct cgroup *cgrp = NULL;
	const char *p, *e, *eos = str + strlen(str);
	char *s;
	int ret, i;

	if (list_empty(&evlist->core.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;
}