cgroup.c

  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 <errno.h>
 14#include <fcntl.h>
 15#include <stdlib.h>
 16#include <string.h>
 17#include <api/fs/fs.h>
 18#include <ftw.h>
 19#include <regex.h>
 20
 21int nr_cgroups;
 22bool cgrp_event_expanded;
 23
 24/* used to match cgroup name with patterns */
 25struct cgroup_name {
 26	struct list_head list;
 27	bool used;
 28	char name[];
 29};
 30static LIST_HEAD(cgroup_list);
 31
 32static int open_cgroup(const char *name)
 33{
 34	char path[PATH_MAX + 1];
 35	char mnt[PATH_MAX + 1];
 36	int fd;
 37
 38
 39	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event"))
 40		return -1;
 41
 42	scnprintf(path, PATH_MAX, "%s/%s", mnt, name);
 43
 44	fd = open(path, O_RDONLY);
 45	if (fd == -1)
 46		fprintf(stderr, "no access to cgroup %s\n", path);
 47
 48	return fd;
 49}
 50
 51#ifdef HAVE_FILE_HANDLE
 52static u64 __read_cgroup_id(const char *path)
 53{
 54	struct {
 55		struct file_handle fh;
 56		uint64_t cgroup_id;
 57	} handle;
 58	int mount_id;
 59
 60	handle.fh.handle_bytes = sizeof(handle.cgroup_id);
 61	if (name_to_handle_at(AT_FDCWD, path, &handle.fh, &mount_id, 0) < 0)
 62		return -1ULL;
 63
 64	return handle.cgroup_id;
 65}
 66
 67int read_cgroup_id(struct cgroup *cgrp)
 68{
 69	char path[PATH_MAX + 1];
 70	char mnt[PATH_MAX + 1];
 71
 72	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, "perf_event"))
 73		return -1;
 74
 75	scnprintf(path, PATH_MAX, "%s/%s", mnt, cgrp->name);
 76
 77	cgrp->id = __read_cgroup_id(path);
 78	return 0;
 79}
 80#else
 81static inline u64 __read_cgroup_id(const char *path __maybe_unused) { return -1ULL; }
 82#endif  /* HAVE_FILE_HANDLE */
 83
 84#ifndef CGROUP2_SUPER_MAGIC
 85#define CGROUP2_SUPER_MAGIC  0x63677270
 86#endif
 87
 88int cgroup_is_v2(const char *subsys)
 89{
 90	char mnt[PATH_MAX + 1];
 91	struct statfs stbuf;
 92
 93	if (cgroupfs_find_mountpoint(mnt, PATH_MAX + 1, subsys))
 94		return -1;
 95
 96	if (statfs(mnt, &stbuf) < 0)
 97		return -1;
 98
 99	return (stbuf.f_type == CGROUP2_SUPER_MAGIC);
100}
101
102static struct cgroup *evlist__find_cgroup(struct evlist *evlist, const char *str)
103{
104	struct evsel *counter;
105	/*
106	 * check if cgrp is already defined, if so we reuse it
107	 */
108	evlist__for_each_entry(evlist, counter) {
109		if (!counter->cgrp)
110			continue;
111		if (!strcmp(counter->cgrp->name, str))
112			return cgroup__get(counter->cgrp);
113	}
114
115	return NULL;
116}
117
118struct cgroup *cgroup__new(const char *name, bool do_open)
119{
120	struct cgroup *cgroup = zalloc(sizeof(*cgroup));
121
122	if (cgroup != NULL) {
123		refcount_set(&cgroup->refcnt, 1);
124
125		cgroup->name = strdup(name);
126		if (!cgroup->name)
127			goto out_err;
128
129		if (do_open) {
130			cgroup->fd = open_cgroup(name);
131			if (cgroup->fd == -1)
132				goto out_free_name;
133		} else {
134			cgroup->fd = -1;
135		}
136	}
137
138	return cgroup;
139
140out_free_name:
141	zfree(&cgroup->name);
142out_err:
143	free(cgroup);
144	return NULL;
145}
146
147struct cgroup *evlist__findnew_cgroup(struct evlist *evlist, const char *name)
148{
149	struct cgroup *cgroup = evlist__find_cgroup(evlist, name);
150
151	return cgroup ?: cgroup__new(name, true);
152}
153
154static int add_cgroup(struct evlist *evlist, const char *str)
155{
156	struct evsel *counter;
157	struct cgroup *cgrp = evlist__findnew_cgroup(evlist, str);
158	int n;
159
160	if (!cgrp)
161		return -1;
162	/*
163	 * find corresponding event
164	 * if add cgroup N, then need to find event N
165	 */
166	n = 0;
167	evlist__for_each_entry(evlist, counter) {
168		if (n == nr_cgroups)
169			goto found;
170		n++;
171	}
172
173	cgroup__put(cgrp);
174	return -1;
175found:
176	counter->cgrp = cgrp;
177	return 0;
178}
179
180static void cgroup__delete(struct cgroup *cgroup)
181{
182	if (cgroup->fd >= 0)
183		close(cgroup->fd);
184	zfree(&cgroup->name);
185	free(cgroup);
186}
187
188void cgroup__put(struct cgroup *cgrp)
189{
190	if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
191		cgroup__delete(cgrp);
192	}
193}
194
195struct cgroup *cgroup__get(struct cgroup *cgroup)
196{
197       if (cgroup)
198		refcount_inc(&cgroup->refcnt);
199       return cgroup;
200}
201
202static void evsel__set_default_cgroup(struct evsel *evsel, struct cgroup *cgroup)
203{
204	if (evsel->cgrp == NULL)
205		evsel->cgrp = cgroup__get(cgroup);
206}
207
208void evlist__set_default_cgroup(struct evlist *evlist, struct cgroup *cgroup)
209{
210	struct evsel *evsel;
211
212	evlist__for_each_entry(evlist, evsel)
213		evsel__set_default_cgroup(evsel, cgroup);
214}
215
216/* helper function for ftw() in match_cgroups and list_cgroups */
217static int add_cgroup_name(const char *fpath, const struct stat *sb __maybe_unused,
218			   int typeflag, struct FTW *ftwbuf __maybe_unused)
219{
220	struct cgroup_name *cn;
221
222	if (typeflag != FTW_D)
223		return 0;
224
225	cn = malloc(sizeof(*cn) + strlen(fpath) + 1);
226	if (cn == NULL)
227		return -1;
228
229	cn->used = false;
230	strcpy(cn->name, fpath);
231
232	list_add_tail(&cn->list, &cgroup_list);
233	return 0;
234}
235
236static int check_and_add_cgroup_name(const char *fpath)
237{
238	struct cgroup_name *cn;
239
240	list_for_each_entry(cn, &cgroup_list, list) {
241		if (!strcmp(cn->name, fpath))
242			return 0;
243	}
244
245	/* pretend if it's added by ftw() */
246	return add_cgroup_name(fpath, NULL, FTW_D, NULL);
247}
248
249static void release_cgroup_list(void)
250{
251	struct cgroup_name *cn;
252
253	while (!list_empty(&cgroup_list)) {
254		cn = list_first_entry(&cgroup_list, struct cgroup_name, list);
255		list_del(&cn->list);
256		free(cn);
257	}
258}
259
260/* collect given cgroups only */
261static int list_cgroups(const char *str)
262{
263	const char *p, *e, *eos = str + strlen(str);
264	struct cgroup_name *cn;
265	char *s;
266
267	/* use given name as is when no regex is given */
268	for (;;) {
269		p = strchr(str, ',');
270		e = p ? p : eos;
271
272		if (e - str) {
273			int ret;
274
275			s = strndup(str, e - str);
276			if (!s)
277				return -1;
278
279			ret = check_and_add_cgroup_name(s);
280			free(s);
281			if (ret < 0)
282				return -1;
283		} else {
284			if (check_and_add_cgroup_name("/") < 0)
285				return -1;
286		}
287
288		if (!p)
289			break;
290		str = p+1;
291	}
292
293	/* these groups will be used */
294	list_for_each_entry(cn, &cgroup_list, list)
295		cn->used = true;
296
297	return 0;
298}
299
300/* collect all cgroups first and then match with the pattern */
301static int match_cgroups(const char *str)
302{
303	char mnt[PATH_MAX];
304	const char *p, *e, *eos = str + strlen(str);
305	struct cgroup_name *cn;
306	regex_t reg;
307	int prefix_len;
308	char *s;
309
310	if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event"))
311		return -1;
312
313	/* cgroup_name will have a full path, skip the root directory */
314	prefix_len = strlen(mnt);
315
316	/* collect all cgroups in the cgroup_list */
317	if (nftw(mnt, add_cgroup_name, 20, 0) < 0)
318		return -1;
319
320	for (;;) {
321		p = strchr(str, ',');
322		e = p ? p : eos;
323
324		/* allow empty cgroups, i.e., skip */
325		if (e - str) {
326			/* termination added */
327			s = strndup(str, e - str);
328			if (!s)
329				return -1;
330			if (regcomp(&reg, s, REG_NOSUB)) {
331				free(s);
332				return -1;
333			}
334
335			/* check cgroup name with the pattern */
336			list_for_each_entry(cn, &cgroup_list, list) {
337				char *name = cn->name + prefix_len;
338
339				if (name[0] == '/' && name[1])
340					name++;
341				if (!regexec(&reg, name, 0, NULL, 0))
342					cn->used = true;
343			}
344			regfree(&reg);
345			free(s);
346		} else {
347			/* first entry to root cgroup */
348			cn = list_first_entry(&cgroup_list, struct cgroup_name,
349					      list);
350			cn->used = true;
351		}
352
353		if (!p)
354			break;
355		str = p+1;
356	}
357	return prefix_len;
358}
359
360int parse_cgroups(const struct option *opt, const char *str,
361		  int unset __maybe_unused)
362{
363	struct evlist *evlist = *(struct evlist **)opt->value;
364	struct evsel *counter;
365	struct cgroup *cgrp = NULL;
366	const char *p, *e, *eos = str + strlen(str);
367	char *s;
368	int ret, i;
369
370	if (list_empty(&evlist->core.entries)) {
371		fprintf(stderr, "must define events before cgroups\n");
372		return -1;
373	}
374
375	for (;;) {
376		p = strchr(str, ',');
377		e = p ? p : eos;
378
379		/* allow empty cgroups, i.e., skip */
380		if (e - str) {
381			/* termination added */
382			s = strndup(str, e - str);
383			if (!s)
384				return -1;
385			ret = add_cgroup(evlist, s);
386			free(s);
387			if (ret)
388				return -1;
389		}
390		/* nr_cgroups is increased een for empty cgroups */
391		nr_cgroups++;
392		if (!p)
393			break;
394		str = p+1;
395	}
396	/* for the case one cgroup combine to multiple events */
397	i = 0;
398	if (nr_cgroups == 1) {
399		evlist__for_each_entry(evlist, counter) {
400			if (i == 0)
401				cgrp = counter->cgrp;
402			else {
403				counter->cgrp = cgrp;
404				refcount_inc(&cgrp->refcnt);
405			}
406			i++;
407		}
408	}
409	return 0;
410}
411
412static bool has_pattern_string(const char *str)
413{
414	return !!strpbrk(str, "{}[]()|*+?^$");
415}
416
417int evlist__expand_cgroup(struct evlist *evlist, const char *str, bool open_cgroup)
418{
419	struct evlist *orig_list, *tmp_list;
420	struct evsel *pos, *evsel, *leader;
421	struct rblist orig_metric_events;
422	struct cgroup *cgrp = NULL;
423	struct cgroup_name *cn;
424	int ret = -1;
425	int prefix_len;
426
427	if (evlist->core.nr_entries == 0) {
428		fprintf(stderr, "must define events before cgroups\n");
429		return -EINVAL;
430	}
431
432	orig_list = evlist__new();
433	tmp_list = evlist__new();
434	if (orig_list == NULL || tmp_list == NULL) {
435		fprintf(stderr, "memory allocation failed\n");
436		return -ENOMEM;
437	}
438
439	/* save original events and init evlist */
440	evlist__splice_list_tail(orig_list, &evlist->core.entries);
441	evlist->core.nr_entries = 0;
442
443	orig_metric_events = evlist->metric_events;
444	metricgroup__rblist_init(&evlist->metric_events);
445
446	if (has_pattern_string(str))
447		prefix_len = match_cgroups(str);
448	else
449		prefix_len = list_cgroups(str);
450
451	if (prefix_len < 0)
452		goto out_err;
453
454	list_for_each_entry(cn, &cgroup_list, list) {
455		char *name;
456
457		if (!cn->used)
458			continue;
459
460		/* cgroup_name might have a full path, skip the prefix */
461		name = cn->name + prefix_len;
462		if (name[0] == '/' && name[1])
463			name++;
464
465		/* the cgroup can go away in the meantime */
466		cgrp = cgroup__new(name, open_cgroup);
467		if (cgrp == NULL)
468			continue;
469
470		leader = NULL;
471		evlist__for_each_entry(orig_list, pos) {
472			evsel = evsel__clone(/*dest=*/NULL, pos);
473			if (evsel == NULL)
474				goto out_err;
475
476			cgroup__put(evsel->cgrp);
477			evsel->cgrp = cgroup__get(cgrp);
478
479			if (evsel__is_group_leader(pos))
480				leader = evsel;
481			evsel__set_leader(evsel, leader);
482
483			evlist__add(tmp_list, evsel);
484		}
485		/* cgroup__new() has a refcount, release it here */
486		cgroup__put(cgrp);
487		nr_cgroups++;
488
489		if (metricgroup__copy_metric_events(tmp_list, cgrp,
490						    &evlist->metric_events,
491						    &orig_metric_events) < 0)
492			goto out_err;
493
494		evlist__splice_list_tail(evlist, &tmp_list->core.entries);
495		tmp_list->core.nr_entries = 0;
496	}
497
498	if (list_empty(&evlist->core.entries)) {
499		fprintf(stderr, "no cgroup matched: %s\n", str);
500		goto out_err;
501	}
502
503	ret = 0;
504	cgrp_event_expanded = true;
505
506out_err:
507	evlist__delete(orig_list);
508	evlist__delete(tmp_list);
509	metricgroup__rblist_exit(&orig_metric_events);
510	release_cgroup_list();
511
512	return ret;
513}
514
515static struct cgroup *__cgroup__findnew(struct rb_root *root, uint64_t id,
516					bool create, const char *path)
517{
518	struct rb_node **p = &root->rb_node;
519	struct rb_node *parent = NULL;
520	struct cgroup *cgrp;
521
522	while (*p != NULL) {
523		parent = *p;
524		cgrp = rb_entry(parent, struct cgroup, node);
525
526		if (cgrp->id == id)
527			return cgrp;
528
529		if (cgrp->id < id)
530			p = &(*p)->rb_left;
531		else
532			p = &(*p)->rb_right;
533	}
534
535	if (!create)
536		return NULL;
537
538	cgrp = malloc(sizeof(*cgrp));
539	if (cgrp == NULL)
540		return NULL;
541
542	cgrp->name = strdup(path);
543	if (cgrp->name == NULL) {
544		free(cgrp);
545		return NULL;
546	}
547
548	cgrp->fd = -1;
549	cgrp->id = id;
550	refcount_set(&cgrp->refcnt, 1);
551
552	rb_link_node(&cgrp->node, parent, p);
553	rb_insert_color(&cgrp->node, root);
554
555	return cgrp;
556}
557
558struct cgroup *cgroup__findnew(struct perf_env *env, uint64_t id,
559			       const char *path)
560{
561	struct cgroup *cgrp;
562
563	down_write(&env->cgroups.lock);
564	cgrp = __cgroup__findnew(&env->cgroups.tree, id, true, path);
565	up_write(&env->cgroups.lock);
566	return cgrp;
567}
568
569struct cgroup *__cgroup__find(struct rb_root *root, uint64_t id)
570{
571	return __cgroup__findnew(root, id, /*create=*/false, /*path=*/NULL);
572}
573
574struct cgroup *cgroup__find(struct perf_env *env, uint64_t id)
575{
576	struct cgroup *cgrp;
577
578	down_read(&env->cgroups.lock);
579	cgrp = __cgroup__findnew(&env->cgroups.tree, id, false, NULL);
580	up_read(&env->cgroups.lock);
581	return cgrp;
582}
583
584void perf_env__purge_cgroups(struct perf_env *env)
585{
586	struct rb_node *node;
587	struct cgroup *cgrp;
588
589	down_write(&env->cgroups.lock);
590	while (!RB_EMPTY_ROOT(&env->cgroups.tree)) {
591		node = rb_first(&env->cgroups.tree);
592		cgrp = rb_entry(node, struct cgroup, node);
593
594		rb_erase(node, &env->cgroups.tree);
595		cgroup__put(cgrp);
596	}
597	up_write(&env->cgroups.lock);
598}
599
600void read_all_cgroups(struct rb_root *root)
601{
602	char mnt[PATH_MAX];
603	struct cgroup_name *cn;
604	int prefix_len;
605
606	if (cgroupfs_find_mountpoint(mnt, sizeof(mnt), "perf_event"))
607		return;
608
609	/* cgroup_name will have a full path, skip the root directory */
610	prefix_len = strlen(mnt);
611
612	/* collect all cgroups in the cgroup_list */
613	if (nftw(mnt, add_cgroup_name, 20, 0) < 0)
614		return;
615
616	list_for_each_entry(cn, &cgroup_list, list) {
617		const char *name;
618		u64 cgrp_id;
619
620		/* cgroup_name might have a full path, skip the prefix */
621		name = cn->name + prefix_len;
622		if (name[0] == '\0')
623			name = "/";
624
625		cgrp_id = __read_cgroup_id(cn->name);
626		__cgroup__findnew(root, cgrp_id, /*create=*/true, name);
627	}
628
629	release_cgroup_list();
630}