tools/lib/perf/evlist.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <perf/evlist.h>
   3 #include <perf/evsel.h>
   4 #include <linux/bitops.h>
   5 #include <linux/list.h>
   6 #include <linux/hash.h>
   7 #include <sys/ioctl.h>
   8 #include <internal/evlist.h>
   9 #include <internal/evsel.h>
  10 #include <internal/xyarray.h>
  11 #include <internal/mmap.h>
  12 #include <internal/cpumap.h>
  13 #include <internal/threadmap.h>
  14 #include <internal/lib.h>
  15 #include <linux/zalloc.h>
  16 #include <stdlib.h>
  17 #include <errno.h>
  18 #include <unistd.h>
  19 #include <fcntl.h>
  20 #include <signal.h>
  21 #include <poll.h>
  22 #include <sys/mman.h>
  23 #include <perf/cpumap.h>
  24 #include <perf/threadmap.h>
  25 #include <api/fd/array.h>
  26 #include "internal.h"
  27
  28 void perf_evlist__init(struct perf_evlist *evlist)
  29 {
  30         INIT_LIST_HEAD(&evlist->entries);
  31         evlist->nr_entries = 0;
  32         fdarray__init(&evlist->pollfd, 64);
  33         perf_evlist__reset_id_hash(evlist);
  34 }
  35
  36 static void __perf_evlist__propagate_maps(struct perf_evlist *evlist,
  37                                           struct perf_evsel *evsel)
  38 {
  39         if (evsel->system_wide) {
  40                 /* System wide: set the cpu map of the evsel to all online CPUs. */
  41                 perf_cpu_map__put(evsel->cpus);
  42                 evsel->cpus = perf_cpu_map__new(NULL);
  43         } else if (evlist->has_user_cpus && evsel->is_pmu_core) {
  44                 /*
  45                  * User requested CPUs on a core PMU, ensure the requested CPUs
  46                  * are valid by intersecting with those of the PMU.
  47                  */
  48                 perf_cpu_map__put(evsel->cpus);
  49                 evsel->cpus = perf_cpu_map__intersect(evlist->user_requested_cpus, evsel->own_cpus);
  50         } else if (!evsel->own_cpus || evlist->has_user_cpus ||
  51                 (!evsel->requires_cpu && perf_cpu_map__has_any_cpu(evlist->user_requested_cpus))) {
  52                 /*
  53                  * The PMU didn't specify a default cpu map, this isn't a core
  54                  * event and the user requested CPUs or the evlist user
  55                  * requested CPUs have the "any CPU" (aka dummy) CPU value. In
  56                  * which case use the user requested CPUs rather than the PMU
  57                  * ones.
  58                  */
  59                 perf_cpu_map__put(evsel->cpus);
  60                 evsel->cpus = perf_cpu_map__get(evlist->user_requested_cpus);
  61         } else if (evsel->cpus != evsel->own_cpus) {
  62                 /*
  63                  * No user requested cpu map but the PMU cpu map doesn't match
  64                  * the evsel's. Reset it back to the PMU cpu map.
  65                  */
  66                 perf_cpu_map__put(evsel->cpus);
  67                 evsel->cpus = perf_cpu_map__get(evsel->own_cpus);
  68         }
  69
  70         if (evsel->system_wide) {
  71                 perf_thread_map__put(evsel->threads);
  72                 evsel->threads = perf_thread_map__new_dummy();
  73         } else {
  74                 perf_thread_map__put(evsel->threads);
  75                 evsel->threads = perf_thread_map__get(evlist->threads);
  76         }
  77
  78         evlist->all_cpus = perf_cpu_map__merge(evlist->all_cpus, evsel->cpus);
  79 }
  80
  81 static void perf_evlist__propagate_maps(struct perf_evlist *evlist)
  82 {
  83         struct perf_evsel *evsel;
  84
  85         evlist->needs_map_propagation = true;
  86
  87         perf_evlist__for_each_evsel(evlist, evsel)
  88                 __perf_evlist__propagate_maps(evlist, evsel);
  89 }
  90
  91 void perf_evlist__add(struct perf_evlist *evlist,
  92                       struct perf_evsel *evsel)
  93 {
  94         evsel->idx = evlist->nr_entries;
  95         list_add_tail(&evsel->node, &evlist->entries);
  96         evlist->nr_entries += 1;
  97
  98         if (evlist->needs_map_propagation)
  99                 __perf_evlist__propagate_maps(evlist, evsel);
 100 }
 101
 102 void perf_evlist__remove(struct perf_evlist *evlist,
 103                          struct perf_evsel *evsel)
 104 {
 105         list_del_init(&evsel->node);
 106         evlist->nr_entries -= 1;
 107 }
 108
 109 struct perf_evlist *perf_evlist__new(void)
 110 {
 111         struct perf_evlist *evlist = zalloc(sizeof(*evlist));
 112
 113         if (evlist != NULL)
 114                 perf_evlist__init(evlist);
 115
 116         return evlist;
 117 }
 118
 119 struct perf_evsel *
 120 perf_evlist__next(struct perf_evlist *evlist, struct perf_evsel *prev)
 121 {
 122         struct perf_evsel *next;
 123
 124         if (!prev) {
 125                 next = list_first_entry(&evlist->entries,
 126                                         struct perf_evsel,
 127                                         node);
 128         } else {
 129                 next = list_next_entry(prev, node);
 130         }
 131
 132         /* Empty list is noticed here so don't need checking on entry. */
 133         if (&next->node == &evlist->entries)
 134                 return NULL;
 135
 136         return next;
 137 }
 138
 139 static void perf_evlist__purge(struct perf_evlist *evlist)
 140 {
 141         struct perf_evsel *pos, *n;
 142
 143         perf_evlist__for_each_entry_safe(evlist, n, pos) {
 144                 list_del_init(&pos->node);
 145                 perf_evsel__delete(pos);
 146         }
 147
 148         evlist->nr_entries = 0;
 149 }
 150
 151 void perf_evlist__exit(struct perf_evlist *evlist)
 152 {
 153         perf_cpu_map__put(evlist->user_requested_cpus);
 154         perf_cpu_map__put(evlist->all_cpus);
 155         perf_thread_map__put(evlist->threads);
 156         evlist->user_requested_cpus = NULL;
 157         evlist->all_cpus = NULL;
 158         evlist->threads = NULL;
 159         fdarray__exit(&evlist->pollfd);
 160 }
 161
 162 void perf_evlist__delete(struct perf_evlist *evlist)
 163 {
 164         if (evlist == NULL)
 165                 return;
 166
 167         perf_evlist__munmap(evlist);
 168         perf_evlist__close(evlist);
 169         perf_evlist__purge(evlist);
 170         perf_evlist__exit(evlist);
 171         free(evlist);
 172 }
 173
 174 void perf_evlist__set_maps(struct perf_evlist *evlist,
 175                            struct perf_cpu_map *cpus,
 176                            struct perf_thread_map *threads)
 177 {
 178         /*
 179          * Allow for the possibility that one or another of the maps isn't being
 180          * changed i.e. don't put it.  Note we are assuming the maps that are
 181          * being applied are brand new and evlist is taking ownership of the
 182          * original reference count of 1.  If that is not the case it is up to
 183          * the caller to increase the reference count.
 184          */
 185         if (cpus != evlist->user_requested_cpus) {
 186                 perf_cpu_map__put(evlist->user_requested_cpus);
 187                 evlist->user_requested_cpus = perf_cpu_map__get(cpus);
 188         }
 189
 190         if (threads != evlist->threads) {
 191                 perf_thread_map__put(evlist->threads);
 192                 evlist->threads = perf_thread_map__get(threads);
 193         }
 194
 195         perf_evlist__propagate_maps(evlist);
 196 }
 197
 198 int perf_evlist__open(struct perf_evlist *evlist)
 199 {
 200         struct perf_evsel *evsel;
 201         int err;
 202
 203         perf_evlist__for_each_entry(evlist, evsel) {
 204                 err = perf_evsel__open(evsel, evsel->cpus, evsel->threads);
 205                 if (err < 0)
 206                         goto out_err;
 207         }
 208
 209         return 0;
 210
 211 out_err:
 212         perf_evlist__close(evlist);
 213         return err;
 214 }
 215
 216 void perf_evlist__close(struct perf_evlist *evlist)
 217 {
 218         struct perf_evsel *evsel;
 219
 220         perf_evlist__for_each_entry_reverse(evlist, evsel)
 221                 perf_evsel__close(evsel);
 222 }
 223
 224 void perf_evlist__enable(struct perf_evlist *evlist)
 225 {
 226         struct perf_evsel *evsel;
 227
 228         perf_evlist__for_each_entry(evlist, evsel)
 229                 perf_evsel__enable(evsel);
 230 }
 231
 232 void perf_evlist__disable(struct perf_evlist *evlist)
 233 {
 234         struct perf_evsel *evsel;
 235
 236         perf_evlist__for_each_entry(evlist, evsel)
 237                 perf_evsel__disable(evsel);
 238 }
 239
 240 u64 perf_evlist__read_format(struct perf_evlist *evlist)
 241 {
 242         struct perf_evsel *first = perf_evlist__first(evlist);
 243
 244         return first->attr.read_format;
 245 }
 246
 247 #define SID(e, x, y) xyarray__entry(e->sample_id, x, y)
 248
 249 static void perf_evlist__id_hash(struct perf_evlist *evlist,
 250                                  struct perf_evsel *evsel,
 251                                  int cpu, int thread, u64 id)
 252 {
 253         int hash;
 254         struct perf_sample_id *sid = SID(evsel, cpu, thread);
 255
 256         sid->id = id;
 257         sid->evsel = evsel;
 258         hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
 259         hlist_add_head(&sid->node, &evlist->heads[hash]);
 260 }
 261
 262 void perf_evlist__reset_id_hash(struct perf_evlist *evlist)
 263 {
 264         int i;
 265
 266         for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
 267                 INIT_HLIST_HEAD(&evlist->heads[i]);
 268 }
 269
 270 void perf_evlist__id_add(struct perf_evlist *evlist,
 271                          struct perf_evsel *evsel,
 272                          int cpu, int thread, u64 id)
 273 {
 274         perf_evlist__id_hash(evlist, evsel, cpu, thread, id);
 275         evsel->id[evsel->ids++] = id;
 276 }
 277
 278 int perf_evlist__id_add_fd(struct perf_evlist *evlist,
 279                            struct perf_evsel *evsel,
 280                            int cpu, int thread, int fd)
 281 {
 282         u64 read_data[4] = { 0, };
 283         int id_idx = 1; /* The first entry is the counter value */
 284         u64 id;
 285         int ret;
 286
 287         ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
 288         if (!ret)
 289                 goto add;
 290
 291         if (errno != ENOTTY)
 292                 return -1;
 293
 294         /* Legacy way to get event id.. All hail to old kernels! */
 295
 296         /*
 297          * This way does not work with group format read, so bail
 298          * out in that case.
 299          */
 300         if (perf_evlist__read_format(evlist) & PERF_FORMAT_GROUP)
 301                 return -1;
 302
 303         if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
 304             read(fd, &read_data, sizeof(read_data)) == -1)
 305                 return -1;
 306
 307         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
 308                 ++id_idx;
 309         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
 310                 ++id_idx;
 311
 312         id = read_data[id_idx];
 313
 314 add:
 315         perf_evlist__id_add(evlist, evsel, cpu, thread, id);
 316         return 0;
 317 }
 318
 319 int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
 320 {
 321         int nr_cpus = perf_cpu_map__nr(evlist->all_cpus);
 322         int nr_threads = perf_thread_map__nr(evlist->threads);
 323         int nfds = 0;
 324         struct perf_evsel *evsel;
 325
 326         perf_evlist__for_each_entry(evlist, evsel) {
 327                 if (evsel->system_wide)
 328                         nfds += nr_cpus;
 329                 else
 330                         nfds += nr_cpus * nr_threads;
 331         }
 332
 333         if (fdarray__available_entries(&evlist->pollfd) < nfds &&
 334             fdarray__grow(&evlist->pollfd, nfds) < 0)
 335                 return -ENOMEM;
 336
 337         return 0;
 338 }
 339
 340 int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd,
 341                             void *ptr, short revent, enum fdarray_flags flags)
 342 {
 343         int pos = fdarray__add(&evlist->pollfd, fd, revent | POLLERR | POLLHUP, flags);
 344
 345         if (pos >= 0) {
 346                 evlist->pollfd.priv[pos].ptr = ptr;
 347                 fcntl(fd, F_SETFL, O_NONBLOCK);
 348         }
 349
 350         return pos;
 351 }
 352
 353 static void perf_evlist__munmap_filtered(struct fdarray *fda, int fd,
 354                                          void *arg __maybe_unused)
 355 {
 356         struct perf_mmap *map = fda->priv[fd].ptr;
 357
 358         if (map)
 359                 perf_mmap__put(map);
 360 }
 361
 362 int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask)
 363 {
 364         return fdarray__filter(&evlist->pollfd, revents_and_mask,
 365                                perf_evlist__munmap_filtered, NULL);
 366 }
 367
 368 int perf_evlist__poll(struct perf_evlist *evlist, int timeout)
 369 {
 370         return fdarray__poll(&evlist->pollfd, timeout);
 371 }
 372
 373 static struct perf_mmap* perf_evlist__alloc_mmap(struct perf_evlist *evlist, bool overwrite)
 374 {
 375         int i;
 376         struct perf_mmap *map;
 377
 378         map = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
 379         if (!map)
 380                 return NULL;
 381
 382         for (i = 0; i < evlist->nr_mmaps; i++) {
 383                 struct perf_mmap *prev = i ? &map[i - 1] : NULL;
 384
 385                 /*
 386                  * When the perf_mmap() call is made we grab one refcount, plus
 387                  * one extra to let perf_mmap__consume() get the last
 388                  * events after all real references (perf_mmap__get()) are
 389                  * dropped.
 390                  *
 391                  * Each PERF_EVENT_IOC_SET_OUTPUT points to this mmap and
 392                  * thus does perf_mmap__get() on it.
 393                  */
 394                 perf_mmap__init(&map[i], prev, overwrite, NULL);
 395         }
 396
 397         return map;
 398 }
 399
 400 static void perf_evsel__set_sid_idx(struct perf_evsel *evsel, int idx, int cpu, int thread)
 401 {
 402         struct perf_sample_id *sid = SID(evsel, cpu, thread);
 403
 404         sid->idx = idx;
 405         sid->cpu = perf_cpu_map__cpu(evsel->cpus, cpu);
 406         sid->tid = perf_thread_map__pid(evsel->threads, thread);
 407 }
 408
 409 static struct perf_mmap*
 410 perf_evlist__mmap_cb_get(struct perf_evlist *evlist, bool overwrite, int idx)
 411 {
 412         struct perf_mmap *maps;
 413
 414         maps = overwrite ? evlist->mmap_ovw : evlist->mmap;
 415
 416         if (!maps) {
 417                 maps = perf_evlist__alloc_mmap(evlist, overwrite);
 418                 if (!maps)
 419                         return NULL;
 420
 421                 if (overwrite)
 422                         evlist->mmap_ovw = maps;
 423                 else
 424                         evlist->mmap = maps;
 425         }
 426
 427         return &maps[idx];
 428 }
 429
 430 #define FD(e, x, y) (*(int *) xyarray__entry(e->fd, x, y))
 431
 432 static int
 433 perf_evlist__mmap_cb_mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
 434                           int output, struct perf_cpu cpu)
 435 {
 436         return perf_mmap__mmap(map, mp, output, cpu);
 437 }
 438
 439 static void perf_evlist__set_mmap_first(struct perf_evlist *evlist, struct perf_mmap *map,
 440                                         bool overwrite)
 441 {
 442         if (overwrite)
 443                 evlist->mmap_ovw_first = map;
 444         else
 445                 evlist->mmap_first = map;
 446 }
 447
 448 static int
 449 mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
 450                int idx, struct perf_mmap_param *mp, int cpu_idx,
 451                int thread, int *_output, int *_output_overwrite, int *nr_mmaps)
 452 {
 453         struct perf_cpu evlist_cpu = perf_cpu_map__cpu(evlist->all_cpus, cpu_idx);
 454         struct perf_evsel *evsel;
 455         int revent;
 456
 457         perf_evlist__for_each_entry(evlist, evsel) {
 458                 bool overwrite = evsel->attr.write_backward;
 459                 enum fdarray_flags flgs;
 460                 struct perf_mmap *map;
 461                 int *output, fd, cpu;
 462
 463                 if (evsel->system_wide && thread)
 464                         continue;
 465
 466                 cpu = perf_cpu_map__idx(evsel->cpus, evlist_cpu);
 467                 if (cpu == -1)
 468                         continue;
 469
 470                 map = ops->get(evlist, overwrite, idx);
 471                 if (map == NULL)
 472                         return -ENOMEM;
 473
 474                 if (overwrite) {
 475                         mp->prot = PROT_READ;
 476                         output   = _output_overwrite;
 477                 } else {
 478                         mp->prot = PROT_READ | PROT_WRITE;
 479                         output   = _output;
 480                 }
 481
 482                 fd = FD(evsel, cpu, thread);
 483
 484                 if (*output == -1) {
 485                         *output = fd;
 486
 487                         /*
 488                          * The last one will be done at perf_mmap__consume(), so that we
 489                          * make sure we don't prevent tools from consuming every last event in
 490                          * the ring buffer.
 491                          *
 492                          * I.e. we can get the POLLHUP meaning that the fd doesn't exist
 493                          * anymore, but the last events for it are still in the ring buffer,
 494                          * waiting to be consumed.
 495                          *
 496                          * Tools can chose to ignore this at their own discretion, but the
 497                          * evlist layer can't just drop it when filtering events in
 498                          * perf_evlist__filter_pollfd().
 499                          */
 500                         refcount_set(&map->refcnt, 2);
 501
 502                         if (ops->idx)
 503                                 ops->idx(evlist, evsel, mp, idx);
 504
 505                         /* Debug message used by test scripts */
 506                         pr_debug("idx %d: mmapping fd %d\n", idx, *output);
 507                         if (ops->mmap(map, mp, *output, evlist_cpu) < 0)
 508                                 return -1;
 509
 510                         *nr_mmaps += 1;
 511
 512                         if (!idx)
 513                                 perf_evlist__set_mmap_first(evlist, map, overwrite);
 514                 } else {
 515                         /* Debug message used by test scripts */
 516                         pr_debug("idx %d: set output fd %d -> %d\n", idx, fd, *output);
 517                         if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
 518                                 return -1;
 519
 520                         perf_mmap__get(map);
 521                 }
 522
 523                 revent = !overwrite ? POLLIN : 0;
 524
 525                 flgs = evsel->system_wide ? fdarray_flag__nonfilterable : fdarray_flag__default;
 526                 if (perf_evlist__add_pollfd(evlist, fd, map, revent, flgs) < 0) {
 527                         perf_mmap__put(map);
 528                         return -1;
 529                 }
 530
 531                 if (evsel->attr.read_format & PERF_FORMAT_ID) {
 532                         if (perf_evlist__id_add_fd(evlist, evsel, cpu, thread,
 533                                                    fd) < 0)
 534                                 return -1;
 535                         perf_evsel__set_sid_idx(evsel, idx, cpu, thread);
 536                 }
 537         }
 538
 539         return 0;
 540 }
 541
 542 static int
 543 mmap_per_thread(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
 544                 struct perf_mmap_param *mp)
 545 {
 546         int nr_threads = perf_thread_map__nr(evlist->threads);
 547         int nr_cpus    = perf_cpu_map__nr(evlist->all_cpus);
 548         int cpu, thread, idx = 0;
 549         int nr_mmaps = 0;
 550
 551         pr_debug("%s: nr cpu values (may include -1) %d nr threads %d\n",
 552                  __func__, nr_cpus, nr_threads);
 553
 554         /* per-thread mmaps */
 555         for (thread = 0; thread < nr_threads; thread++, idx++) {
 556                 int output = -1;
 557                 int output_overwrite = -1;
 558
 559                 if (mmap_per_evsel(evlist, ops, idx, mp, 0, thread, &output,
 560                                    &output_overwrite, &nr_mmaps))
 561                         goto out_unmap;
 562         }
 563
 564         /* system-wide mmaps i.e. per-cpu */
 565         for (cpu = 1; cpu < nr_cpus; cpu++, idx++) {
 566                 int output = -1;
 567                 int output_overwrite = -1;
 568
 569                 if (mmap_per_evsel(evlist, ops, idx, mp, cpu, 0, &output,
 570                                    &output_overwrite, &nr_mmaps))
 571                         goto out_unmap;
 572         }
 573
 574         if (nr_mmaps != evlist->nr_mmaps)
 575                 pr_err("Miscounted nr_mmaps %d vs %d\n", nr_mmaps, evlist->nr_mmaps);
 576
 577         return 0;
 578
 579 out_unmap:
 580         perf_evlist__munmap(evlist);
 581         return -1;
 582 }
 583
 584 static int
 585 mmap_per_cpu(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
 586              struct perf_mmap_param *mp)
 587 {
 588         int nr_threads = perf_thread_map__nr(evlist->threads);
 589         int nr_cpus    = perf_cpu_map__nr(evlist->all_cpus);
 590         int nr_mmaps = 0;
 591         int cpu, thread;
 592
 593         pr_debug("%s: nr cpu values %d nr threads %d\n", __func__, nr_cpus, nr_threads);
 594
 595         for (cpu = 0; cpu < nr_cpus; cpu++) {
 596                 int output = -1;
 597                 int output_overwrite = -1;
 598
 599                 for (thread = 0; thread < nr_threads; thread++) {
 600                         if (mmap_per_evsel(evlist, ops, cpu, mp, cpu,
 601                                            thread, &output, &output_overwrite, &nr_mmaps))
 602                                 goto out_unmap;
 603                 }
 604         }
 605
 606         if (nr_mmaps != evlist->nr_mmaps)
 607                 pr_err("Miscounted nr_mmaps %d vs %d\n", nr_mmaps, evlist->nr_mmaps);
 608
 609         return 0;
 610
 611 out_unmap:
 612         perf_evlist__munmap(evlist);
 613         return -1;
 614 }
 615
 616 static int perf_evlist__nr_mmaps(struct perf_evlist *evlist)
 617 {
 618         int nr_mmaps;
 619
 620         /* One for each CPU */
 621         nr_mmaps = perf_cpu_map__nr(evlist->all_cpus);
 622         if (perf_cpu_map__empty(evlist->all_cpus)) {
 623                 /* Plus one for each thread */
 624                 nr_mmaps += perf_thread_map__nr(evlist->threads);
 625                 /* Minus the per-thread CPU (-1) */
 626                 nr_mmaps -= 1;
 627         }
 628
 629         return nr_mmaps;
 630 }
 631
 632 int perf_evlist__mmap_ops(struct perf_evlist *evlist,
 633                           struct perf_evlist_mmap_ops *ops,
 634                           struct perf_mmap_param *mp)
 635 {
 636         const struct perf_cpu_map *cpus = evlist->all_cpus;
 637         struct perf_evsel *evsel;
 638
 639         if (!ops || !ops->get || !ops->mmap)
 640                 return -EINVAL;
 641
 642         mp->mask = evlist->mmap_len - page_size - 1;
 643
 644         evlist->nr_mmaps = perf_evlist__nr_mmaps(evlist);
 645
 646         perf_evlist__for_each_entry(evlist, evsel) {
 647                 if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
 648                     evsel->sample_id == NULL &&
 649                     perf_evsel__alloc_id(evsel, evsel->fd->max_x, evsel->fd->max_y) < 0)
 650                         return -ENOMEM;
 651         }
 652
 653         if (evlist->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
 654                 return -ENOMEM;
 655
 656         if (perf_cpu_map__empty(cpus))
 657                 return mmap_per_thread(evlist, ops, mp);
 658
 659         return mmap_per_cpu(evlist, ops, mp);
 660 }
 661
 662 int perf_evlist__mmap(struct perf_evlist *evlist, int pages)
 663 {
 664         struct perf_mmap_param mp;
 665         struct perf_evlist_mmap_ops ops = {
 666                 .get  = perf_evlist__mmap_cb_get,
 667                 .mmap = perf_evlist__mmap_cb_mmap,
 668         };
 669
 670         evlist->mmap_len = (pages + 1) * page_size;
 671
 672         return perf_evlist__mmap_ops(evlist, &ops, &mp);
 673 }
 674
 675 void perf_evlist__munmap(struct perf_evlist *evlist)
 676 {
 677         int i;
 678
 679         if (evlist->mmap) {
 680                 for (i = 0; i < evlist->nr_mmaps; i++)
 681                         perf_mmap__munmap(&evlist->mmap[i]);
 682         }
 683
 684         if (evlist->mmap_ovw) {
 685                 for (i = 0; i < evlist->nr_mmaps; i++)
 686                         perf_mmap__munmap(&evlist->mmap_ovw[i]);
 687         }
 688
 689         zfree(&evlist->mmap);
 690         zfree(&evlist->mmap_ovw);
 691 }
 692
 693 struct perf_mmap*
 694 perf_evlist__next_mmap(struct perf_evlist *evlist, struct perf_mmap *map,
 695                        bool overwrite)
 696 {
 697         if (map)
 698                 return map->next;
 699
 700         return overwrite ? evlist->mmap_ovw_first : evlist->mmap_first;
 701 }
 702
 703 void __perf_evlist__set_leader(struct list_head *list, struct perf_evsel *leader)
 704 {
 705         struct perf_evsel *evsel;
 706         int n = 0;
 707
 708         __perf_evlist__for_each_entry(list, evsel) {
 709                 evsel->leader = leader;
 710                 n++;
 711         }
 712         leader->nr_members = n;
 713 }
 714
 715 void perf_evlist__set_leader(struct perf_evlist *evlist)
 716 {
 717         if (evlist->nr_entries) {
 718                 struct perf_evsel *first = list_entry(evlist->entries.next,
 719                                                 struct perf_evsel, node);
 720
 721                 __perf_evlist__set_leader(&evlist->entries, first);
 722         }
 723 }
 724
 725 int perf_evlist__nr_groups(struct perf_evlist *evlist)
 726 {
 727         struct perf_evsel *evsel;
 728         int nr_groups = 0;
 729
 730         perf_evlist__for_each_evsel(evlist, evsel) {
 731                 /*
 732                  * evsels by default have a nr_members of 1, and they are their
 733                  * own leader. If the nr_members is >1 then this is an
 734                  * indication of a group.
 735                  */
 736                 if (evsel->leader == evsel && evsel->nr_members > 1)
 737                         nr_groups++;
 738         }
 739         return nr_groups;
 740 }