1// SPDX-License-Identifier: GPL-2.0
  2#include <subcmd/parse-options.h>
  3#include "evsel.h"
  4#include "cgroup.h"
  5#include "evlist.h"
  6#include "rblist.h"
  7#include "metricgroup.h"
  8#include "stat.h"
  9#include <linux/zalloc.h>
 10#include <sys/types.h>
 11#include <sys/stat.h>
 12#include <sys/statfs.h>
 13#include <fcntl.h>
 14#include <stdlib.h>
 15#include <string.h>
 16#include <api/fs/fs.h>
 17#include <ftw.h>
 18#include <regex.h>
 19
 20int nr_cgroups;
 21bool cgrp_event_expanded;
 22
 23/* used to match cgroup name with patterns */
 24struct cgroup_name {
 25	struct list_head list;
 26	bool used;
 27	char name[];
 28};
 29static LIST_HEAD(cgroup_list);
 30
 31static int open_cgroup(const char *name)
 32{
 33	char path[PATH_MAX + 1];
 34	char mnt[PATH_MAX + 1];
 35	int fd;
 36
 37
 38	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event"))
 39		return -1;
 40
 41	scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
 42
 43	fd = open(path, O_RDONLY);
 44	if (fd == -1)
 45		fprintf(stderr, "no access to cgroup %s\n", path);
 46
 47	return fd;
 48}
 49
 50#ifdef HAVE_FILE_HANDLE
 51int read_cgroup_id(struct cgroup *cgrp)
 52{
 53	char path[PATH_MAX + 1];
 54	char mnt[PATH_MAX + 1];
 55	struct {
 56		struct file_handle fh;
 57		uint64_t cgroup_id;
 58	} handle;
 59	int mount_id;
 60
 61	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event"))
 62		return -1;
 63
 64	scnprintf(path, PATH_MAX, "%s/%s", mnt, cgrp->name);
 65
 66	handle.fh.handle_bytes = sizeof(handle.cgroup_id);
 67	if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0)
 68		return -1;
 69
 70	cgrp->id = handle.cgroup_id;
 71	return 0;
 72}
 73#endif  /* HAVE_FILE_HANDLE */
 74
 75#ifndef CGROUP2_SUPER_MAGIC
 76#define CGROUP2_SUPER_MAGIC  0x63677270
 77#endif
 78
 79int cgroup_is_v2(const char *subsys)
 80{
 81	char mnt[PATH_MAX + 1];
 82	struct statfs stbuf;
 83
 84	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, subsys))
 85		return -1;
 86
 87	if (statfs(mnt, &stbuf) < 0)
 88		return -1;
 89
 90	return (stbuf.f_type == CGROUP2_SUPER_MAGIC);
 91}
 92
 93static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str)
 94{
 95	struct evsel *counter;
 96	/*
 97	 * check if cgrp is already defined, if so we reuse it
 98	 */
 99	evlist__for_each_entry(evlist, counter) {
100		if (!counter->cgrp)
101			continue;
102		if (!strcmp(counter->cgrp->name, str))
103			return cgroup__get(counter->cgrp);
104	}
105
106	return NULL;
107}
108
109static struct cgroup *cgroup__new(const char *name, bool do_open)
110{
111	struct cgroup *cgroup = zalloc(sizeof(*cgroup));
112
113	if (cgroup != NULL) {
114		refcount_set(&cgroup->refcnt, 1);
115
116		cgroup->name = strdup(name);
117		if (!cgroup->name)
118			goto out_err;
119
120		if (do_open) {
121			cgroup->fd = open_cgroup(name);
122			if (cgroup->fd == -1)
123				goto out_free_name;
124		} else {
125			cgroup->fd = -1;
126		}
127	}
128
129	return cgroup;
130
131out_free_name:
132	zfree(&cgroup->name);
133out_err:
134	free(cgroup);
135	return NULL;
136}
137
138struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
139{
140	struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
141
142	return cgroup ?: cgroup__new(name, true);
143}
144
145static int add_cgroup(struct evlist *evlist, const char *str)
146{
147	struct evsel *counter;
148	struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
149	int n;
150
151	if (!cgrp)
152		return -1;
153	/*
154	 * find corresponding event
155	 * if add cgroup N, then need to find event N
156	 */
157	n = 0;
158	evlist__for_each_entry(evlist, counter) {
159		if (n == nr_cgroups)
160			goto found;
161		n++;
162	}
163
164	cgroup__put(cgrp);
165	return -1;
166found:
167	counter->cgrp = cgrp;
168	return 0;
169}
170
171static void cgroup__delete(struct cgroup *cgroup)
172{
173	if (cgroup->fd >= 0)
174		close(cgroup->fd);
175	zfree(&cgroup->name);
176	free(cgroup);
177}
178
179void cgroup__put(struct cgroup *cgrp)
180{
181	if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
182		cgroup__delete(cgrp);
183	}
184}
185
186struct cgroup *cgroup__get(struct cgroup *cgroup)
187{
188       if (cgroup)
189		refcount_inc(&cgroup->refcnt);
190       return cgroup;
191}
192
193static void evsel__set_default_cgroup(struct evsel *evsel, struct cgroup *cgroup)
194{
195	if (evsel->cgrp == NULL)
196		evsel->cgrp = cgroup__get(cgroup);
197}
198
199void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
200{
201	struct evsel *evsel;
202
203	evlist__for_each_entry(evlist, evsel)
204		evsel__set_default_cgroup(evsel, cgroup);
205}
206
207/* helper function for ftw() in match_cgroups and list_cgroups */
208static int add_cgroup_name(const char *fpath, const struct stat *sb __maybe_unused,
209			   int typeflag, struct FTW *ftwbuf __maybe_unused)
210{
211	struct cgroup_name *cn;
212
213	if (typeflag != FTW_D)
214		return 0;
215
216	cn = malloc(sizeof(*cn) + strlen(fpath) + 1);
217	if (cn == NULL)
218		return -1;
219
220	cn->used = false;
221	strcpy(cn->name, fpath);
222
223	list_add_tail(&cn->list, &cgroup_list);
224	return 0;
225}
226
227static int check_and_add_cgroup_name(const char *fpath)
228{
229	struct cgroup_name *cn;
230
231	list_for_each_entry(cn, &cgroup_list, list) {
232		if (!strcmp(cn->name, fpath))
233			return 0;
234	}
235
236	/* pretend if it's added by ftw() */
237	return add_cgroup_name(fpath, NULL, FTW_D, NULL);
238}
239
240static void release_cgroup_list(void)
241{
242	struct cgroup_name *cn;
243
244	while (!list_empty(&cgroup_list)) {
245		cn = list_first_entry(&cgroup_list, struct cgroup_name, list);
246		list_del(&cn->list);
247		free(cn);
248	}
249}
250
251/* collect given cgroups only */
252static int list_cgroups(const char *str)
253{
254	const char *p, *e, *eos = str + strlen(str);
255	struct cgroup_name *cn;
256	char *s;
257
258	/* use given name as is when no regex is given */
259	for (;;) {
260		p = strchr(str, ',');
261		e = p ? p : eos;
262
263		if (e - str) {
264			int ret;
265
266			s = strndup(str, e - str);
267			if (!s)
268				return -1;
269
270			ret = check_and_add_cgroup_name(s);
271			free(s);
272			if (ret < 0)
273				return -1;
274		} else {
275			if (check_and_add_cgroup_name("/") < 0)
276				return -1;
277		}
278
279		if (!p)
280			break;
281		str = p+1;
282	}
283
284	/* these groups will be used */
285	list_for_each_entry(cn, &cgroup_list, list)
286		cn->used = true;
287
288	return 0;
289}
290
291/* collect all cgroups first and then match with the pattern */
292static int match_cgroups(const char *str)
293{
294	char mnt[PATH_MAX];
295	const char *p, *e, *eos = str + strlen(str);
296	struct cgroup_name *cn;
297	regex_t reg;
298	int prefix_len;
299	char *s;
300
301	if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event"))
302		return -1;
303
304	/* cgroup_name will have a full path, skip the root directory */
305	prefix_len = strlen(mnt);
306
307	/* collect all cgroups in the cgroup_list */
308	if (nftw(mnt, add_cgroup_name, 20, 0) < 0)
309		return -1;
310
311	for (;;) {
312		p = strchr(str, ',');
313		e = p ? p : eos;
314
315		/* allow empty cgroups, i.e., skip */
316		if (e - str) {
317			/* termination added */
318			s = strndup(str, e - str);
319			if (!s)
320				return -1;
321			if (regcomp(&reg, s, REG_NOSUB)) {
322				free(s);
323				return -1;
324			}
325
326			/* check cgroup name with the pattern */
327			list_for_each_entry(cn, &cgroup_list, list) {
328				char *name = cn->name + prefix_len;
329
330				if (name[0] == '/' && name[1])
331					name++;
332				if (!regexec(&reg, name, 0, NULL, 0))
333					cn->used = true;
334			}
335			regfree(&reg);
336			free(s);
337		} else {
338			/* first entry to root cgroup */
339			cn = list_first_entry(&cgroup_list, struct cgroup_name,
340					      list);
341			cn->used = true;
342		}
343
344		if (!p)
345			break;
346		str = p+1;
347	}
348	return prefix_len;
349}
350
351int parse_cgroups(const struct option *opt, const char *str,
352		  int unset __maybe_unused)
353{
354	struct evlist *evlist = *(struct evlist **)opt->value;
355	struct evsel *counter;
356	struct cgroup *cgrp = NULL;
357	const char *p, *e, *eos = str + strlen(str);
358	char *s;
359	int ret, i;
360
361	if (list_empty(&evlist->core.entries)) {
362		fprintf(stderr, "must define events before cgroups\n");
363		return -1;
364	}
365
366	for (;;) {
367		p = strchr(str, ',');
368		e = p ? p : eos;
369
370		/* allow empty cgroups, i.e., skip */
371		if (e - str) {
372			/* termination added */
373			s = strndup(str, e - str);
374			if (!s)
375				return -1;
376			ret = add_cgroup(evlist, s);
377			free(s);
378			if (ret)
379				return -1;
380		}
381		/* nr_cgroups is increased een for empty cgroups */
382		nr_cgroups++;
383		if (!p)
384			break;
385		str = p+1;
386	}
387	/* for the case one cgroup combine to multiple events */
388	i = 0;
389	if (nr_cgroups == 1) {
390		evlist__for_each_entry(evlist, counter) {
391			if (i == 0)
392				cgrp = counter->cgrp;
393			else {
394				counter->cgrp = cgrp;
395				refcount_inc(&cgrp->refcnt);
396			}
397			i++;
398		}
399	}
400	return 0;
401}
402
403static bool has_pattern_string(const char *str)
404{
405	return !!strpbrk(str, "{}[]()|*+?^$");
406}
407
408int evlist__expand_cgroup(struct evlist *evlist, const char *str,
409			  struct rblist *metric_events, bool open_cgroup)
410{
411	struct evlist *orig_list, *tmp_list;
412	struct evsel *pos, *evsel, *leader;
413	struct rblist orig_metric_events;
414	struct cgroup *cgrp = NULL;
415	struct cgroup_name *cn;
416	int ret = -1;
417	int prefix_len;
418
419	if (evlist->core.nr_entries == 0) {
420		fprintf(stderr, "must define events before cgroups\n");
421		return -EINVAL;
422	}
423
424	orig_list = evlist__new();
425	tmp_list = evlist__new();
426	if (orig_list == NULL || tmp_list == NULL) {
427		fprintf(stderr, "memory allocation failed\n");
428		return -ENOMEM;
429	}
430
431	/* save original events and init evlist */
432	evlist__splice_list_tail(orig_list, &evlist->core.entries);
433	evlist->core.nr_entries = 0;
434
435	if (metric_events) {
436		orig_metric_events = *metric_events;
437		rblist__init(metric_events);
438	} else {
439		rblist__init(&orig_metric_events);
440	}
441
442	if (has_pattern_string(str))
443		prefix_len = match_cgroups(str);
444	else
445		prefix_len = list_cgroups(str);
446
447	if (prefix_len < 0)
448		goto out_err;
449
450	list_for_each_entry(cn, &cgroup_list, list) {
451		char *name;
452
453		if (!cn->used)
454			continue;
455
456		/* cgroup_name might have a full path, skip the prefix */
457		name = cn->name + prefix_len;
458		if (name[0] == '/' && name[1])
459			name++;
460		cgrp = cgroup__new(name, open_cgroup);
461		if (cgrp == NULL)
462			goto out_err;
463
464		leader = NULL;
465		evlist__for_each_entry(orig_list, pos) {
466			evsel = evsel__clone(pos);
467			if (evsel == NULL)
468				goto out_err;
469
470			cgroup__put(evsel->cgrp);
471			evsel->cgrp = cgroup__get(cgrp);
472
473			if (evsel__is_group_leader(pos))
474				leader = evsel;
475			evsel__set_leader(evsel, leader);
476
477			evlist__add(tmp_list, evsel);
478		}
479		/* cgroup__new() has a refcount, release it here */
480		cgroup__put(cgrp);
481		nr_cgroups++;
482
483		if (metric_events) {
484			perf_stat__collect_metric_expr(tmp_list);
485			if (metricgroup__copy_metric_events(tmp_list, cgrp,
486							    metric_events,
487							    &orig_metric_events) < 0)
488				goto out_err;
489		}
490
491		evlist__splice_list_tail(evlist, &tmp_list->core.entries);
492		tmp_list->core.nr_entries = 0;
493	}
494
495	if (list_empty(&evlist->core.entries)) {
496		fprintf(stderr, "no cgroup matched: %s\n", str);
497		goto out_err;
498	}
499
500	ret = 0;
501	cgrp_event_expanded = true;
502
503out_err:
504	evlist__delete(orig_list);
505	evlist__delete(tmp_list);
506	rblist__exit(&orig_metric_events);
507	release_cgroup_list();
508
509	return ret;
510}
511
512static struct cgroup *__cgroup__findnew(struct rb_root *root, uint64_t id,
513					bool create, const char *path)
514{
515	struct rb_node **p = &root->rb_node;
516	struct rb_node *parent = NULL;
517	struct cgroup *cgrp;
518
519	while (*p != NULL) {
520		parent = *p;
521		cgrp = rb_entry(parent, struct cgroup, node);
522
523		if (cgrp->id == id)
524			return cgrp;
525
526		if (cgrp->id < id)
527			p = &(*p)->rb_left;
528		else
529			p = &(*p)->rb_right;
530	}
531
532	if (!create)
533		return NULL;
534
535	cgrp = malloc(sizeof(*cgrp));
536	if (cgrp == NULL)
537		return NULL;
538
539	cgrp->name = strdup(path);
540	if (cgrp->name == NULL) {
541		free(cgrp);
542		return NULL;
543	}
544
545	cgrp->fd = -1;
546	cgrp->id = id;
547	refcount_set(&cgrp->refcnt, 1);
548
549	rb_link_node(&cgrp->node, parent, p);
550	rb_insert_color(&cgrp->node, root);
551
552	return cgrp;
553}
554
555struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id,
556			       const char *path)
557{
558	struct cgroup *cgrp;
559
560	down_write(&env->cgroups.lock);
561	cgrp = __cgroup__findnew(&env->cgroups.tree, id, true, path);
562	up_write(&env->cgroups.lock);
563	return cgrp;
564}
565
566struct cgroup *cgroup__find(struct perf_env *env, uint64_t id)
567{
568	struct cgroup *cgrp;
569
570	down_read(&env->cgroups.lock);
571	cgrp = __cgroup__findnew(&env->cgroups.tree, id, false, NULL);
572	up_read(&env->cgroups.lock);
573	return cgrp;
574}
575
576void perf_env__purge_cgroups(struct perf_env *env)
577{
578	struct rb_node *node;
579	struct cgroup *cgrp;
580
581	down_write(&env->cgroups.lock);
582	while (!RB_EMPTY_ROOT(&env->cgroups.tree)) {
583		node = rb_first(&env->cgroups.tree);
584		cgrp = rb_entry(node, struct cgroup, node);
585
586		rb_erase(node, &env->cgroups.tree);
587		cgroup__put(cgrp);
588	}
589	up_write(&env->cgroups.lock);
590}

  1// SPDX-License-Identifier: GPL-2.0
  2#include <subcmd/parse-options.h>
  3#include "evsel.h"
  4#include "cgroup.h"
  5#include "evlist.h"
 
 
 
  6#include <linux/zalloc.h>
  7#include <sys/types.h>
  8#include <sys/stat.h>
 
  9#include <fcntl.h>
 10#include <stdlib.h>
 11#include <string.h>
 12#include <api/fs/fs.h>
 
 
 13
 14int nr_cgroups;
 
 
 
 
 
 
 
 
 
 15
 16static int open_cgroup(const char *name)
 17{
 18	char path[PATH_MAX + 1];
 19	char mnt[PATH_MAX + 1];
 20	int fd;
 21
 22
 23	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event"))
 24		return -1;
 25
 26	scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
 27
 28	fd = open(path, O_RDONLY);
 29	if (fd == -1)
 30		fprintf(stderr, "no access to cgroup %s\n", path);
 31
 32	return fd;
 33}
 34
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 35static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str)
 36{
 37	struct evsel *counter;
 38	/*
 39	 * check if cgrp is already defined, if so we reuse it
 40	 */
 41	evlist__for_each_entry(evlist, counter) {
 42		if (!counter->cgrp)
 43			continue;
 44		if (!strcmp(counter->cgrp->name, str))
 45			return cgroup__get(counter->cgrp);
 46	}
 47
 48	return NULL;
 49}
 50
 51static struct cgroup *cgroup__new(const char *name)
 52{
 53	struct cgroup *cgroup = zalloc(sizeof(*cgroup));
 54
 55	if (cgroup != NULL) {
 56		refcount_set(&cgroup->refcnt, 1);
 57
 58		cgroup->name = strdup(name);
 59		if (!cgroup->name)
 60			goto out_err;
 61		cgroup->fd = open_cgroup(name);
 62		if (cgroup->fd == -1)
 63			goto out_free_name;
 
 
 
 
 
 64	}
 65
 66	return cgroup;
 67
 68out_free_name:
 69	zfree(&cgroup->name);
 70out_err:
 71	free(cgroup);
 72	return NULL;
 73}
 74
 75struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
 76{
 77	struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
 78
 79	return cgroup ?: cgroup__new(name);
 80}
 81
 82static int add_cgroup(struct evlist *evlist, const char *str)
 83{
 84	struct evsel *counter;
 85	struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
 86	int n;
 87
 88	if (!cgrp)
 89		return -1;
 90	/*
 91	 * find corresponding event
 92	 * if add cgroup N, then need to find event N
 93	 */
 94	n = 0;
 95	evlist__for_each_entry(evlist, counter) {
 96		if (n == nr_cgroups)
 97			goto found;
 98		n++;
 99	}
100
101	cgroup__put(cgrp);
102	return -1;
103found:
104	counter->cgrp = cgrp;
105	return 0;
106}
107
108static void cgroup__delete(struct cgroup *cgroup)
109{
110	if (cgroup->fd >= 0)
111		close(cgroup->fd);
112	zfree(&cgroup->name);
113	free(cgroup);
114}
115
116void cgroup__put(struct cgroup *cgrp)
117{
118	if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
119		cgroup__delete(cgrp);
120	}
121}
122
123struct cgroup *cgroup__get(struct cgroup *cgroup)
124{
125       if (cgroup)
126		refcount_inc(&cgroup->refcnt);
127       return cgroup;
128}
129
130static void evsel__set_default_cgroup(struct evsel *evsel, struct cgroup *cgroup)
131{
132	if (evsel->cgrp == NULL)
133		evsel->cgrp = cgroup__get(cgroup);
134}
135
136void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
137{
138	struct evsel *evsel;
139
140	evlist__for_each_entry(evlist, evsel)
141		evsel__set_default_cgroup(evsel, cgroup);
142}
143
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
144int parse_cgroups(const struct option *opt, const char *str,
145		  int unset __maybe_unused)
146{
147	struct evlist *evlist = *(struct evlist **)opt->value;
148	struct evsel *counter;
149	struct cgroup *cgrp = NULL;
150	const char *p, *e, *eos = str + strlen(str);
151	char *s;
152	int ret, i;
153
154	if (list_empty(&evlist->core.entries)) {
155		fprintf(stderr, "must define events before cgroups\n");
156		return -1;
157	}
158
159	for (;;) {
160		p = strchr(str, ',');
161		e = p ? p : eos;
162
163		/* allow empty cgroups, i.e., skip */
164		if (e - str) {
165			/* termination added */
166			s = strndup(str, e - str);
167			if (!s)
168				return -1;
169			ret = add_cgroup(evlist, s);
170			free(s);
171			if (ret)
172				return -1;
173		}
174		/* nr_cgroups is increased een for empty cgroups */
175		nr_cgroups++;
176		if (!p)
177			break;
178		str = p+1;
179	}
180	/* for the case one cgroup combine to multiple events */
181	i = 0;
182	if (nr_cgroups == 1) {
183		evlist__for_each_entry(evlist, counter) {
184			if (i == 0)
185				cgrp = counter->cgrp;
186			else {
187				counter->cgrp = cgrp;
188				refcount_inc(&cgrp->refcnt);
189			}
190			i++;
191		}
192	}
193	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
194}
195
196static struct cgroup *__cgroup__findnew(struct rb_root *root, uint64_t id,
197					bool create, const char *path)
198{
199	struct rb_node **p = &root->rb_node;
200	struct rb_node *parent = NULL;
201	struct cgroup *cgrp;
202
203	while (*p != NULL) {
204		parent = *p;
205		cgrp = rb_entry(parent, struct cgroup, node);
206
207		if (cgrp->id == id)
208			return cgrp;
209
210		if (cgrp->id < id)
211			p = &(*p)->rb_left;
212		else
213			p = &(*p)->rb_right;
214	}
215
216	if (!create)
217		return NULL;
218
219	cgrp = malloc(sizeof(*cgrp));
220	if (cgrp == NULL)
221		return NULL;
222
223	cgrp->name = strdup(path);
224	if (cgrp->name == NULL) {
225		free(cgrp);
226		return NULL;
227	}
228
229	cgrp->fd = -1;
230	cgrp->id = id;
231	refcount_set(&cgrp->refcnt, 1);
232
233	rb_link_node(&cgrp->node, parent, p);
234	rb_insert_color(&cgrp->node, root);
235
236	return cgrp;
237}
238
239struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id,
240			       const char *path)
241{
242	struct cgroup *cgrp;
243
244	down_write(&env->cgroups.lock);
245	cgrp = __cgroup__findnew(&env->cgroups.tree, id, true, path);
246	up_write(&env->cgroups.lock);
247	return cgrp;
248}
249
250struct cgroup *cgroup__find(struct perf_env *env, uint64_t id)
251{
252	struct cgroup *cgrp;
253
254	down_read(&env->cgroups.lock);
255	cgrp = __cgroup__findnew(&env->cgroups.tree, id, false, NULL);
256	up_read(&env->cgroups.lock);
257	return cgrp;
258}
259
260void perf_env__purge_cgroups(struct perf_env *env)
261{
262	struct rb_node *node;
263	struct cgroup *cgrp;
264
265	down_write(&env->cgroups.lock);
266	while (!RB_EMPTY_ROOT(&env->cgroups.tree)) {
267		node = rb_first(&env->cgroups.tree);
268		cgrp = rb_entry(node, struct cgroup, node);
269
270		rb_erase(node, &env->cgroups.tree);
271		cgroup__put(cgrp);
272	}
273	up_write(&env->cgroups.lock);
274}