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