summaryrefslogtreecommitdiff
path: root/tools/lib/perf/evlist.c
blob: 3acbbccc19019c4baa11f82ea253daacd73f7603 (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
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
// SPDX-License-Identifier: GPL-2.0
#include <perf/evlist.h>
#include <perf/evsel.h>
#include <linux/bitops.h>
#include <linux/list.h>
#include <linux/hash.h>
#include <sys/ioctl.h>
#include <internal/evlist.h>
#include <internal/evsel.h>
#include <internal/xyarray.h>
#include <internal/mmap.h>
#include <internal/cpumap.h>
#include <internal/threadmap.h>
#include <internal/lib.h>
#include <linux/zalloc.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <poll.h>
#include <sys/mman.h>
#include <perf/cpumap.h>
#include <perf/threadmap.h>
#include <api/fd/array.h>
#include "internal.h"

void perf_evlist__init(struct perf_evlist *evlist)
{
	INIT_LIST_HEAD(&evlist->entries);
	evlist->nr_entries = 0;
	fdarray__init(&evlist->pollfd, 64);
	perf_evlist__reset_id_hash(evlist);
}

static void __perf_evlist__propagate_maps(struct perf_evlist *evlist,
					  struct perf_evsel *evsel)
{
	if (evsel->system_wide) {
		/* System wide: set the cpu map of the evsel to all online CPUs. */
		perf_cpu_map__put(evsel->cpus);
		evsel->cpus = perf_cpu_map__new(NULL);
	} else if (evlist->has_user_cpus && evsel->is_pmu_core) {
		/*
		 * User requested CPUs on a core PMU, ensure the requested CPUs
		 * are valid by intersecting with those of the PMU.
		 */
		perf_cpu_map__put(evsel->cpus);
		evsel->cpus = perf_cpu_map__intersect(evlist->user_requested_cpus, evsel->own_cpus);
	} else if (!evsel->own_cpus || evlist->has_user_cpus ||
		(!evsel->requires_cpu && perf_cpu_map__has_any_cpu(evlist->user_requested_cpus))) {
		/*
		 * The PMU didn't specify a default cpu map, this isn't a core
		 * event and the user requested CPUs or the evlist user
		 * requested CPUs have the "any CPU" (aka dummy) CPU value. In
		 * which case use the user requested CPUs rather than the PMU
		 * ones.
		 */
		perf_cpu_map__put(evsel->cpus);
		evsel->cpus = perf_cpu_map__get(evlist->user_requested_cpus);
	} else if (evsel->cpus != evsel->own_cpus) {
		/*
		 * No user requested cpu map but the PMU cpu map doesn't match
		 * the evsel's. Reset it back to the PMU cpu map.
		 */
		perf_cpu_map__put(evsel->cpus);
		evsel->cpus = perf_cpu_map__get(evsel->own_cpus);
	}

	if (evsel->system_wide) {
		perf_thread_map__put(evsel->threads);
		evsel->threads = perf_thread_map__new_dummy();
	} else {
		perf_thread_map__put(evsel->threads);
		evsel->threads = perf_thread_map__get(evlist->threads);
	}

	evlist->all_cpus = perf_cpu_map__merge(evlist->all_cpus, evsel->cpus);
}

static void perf_evlist__propagate_maps(struct perf_evlist *evlist)
{
	struct perf_evsel *evsel;

	evlist->needs_map_propagation = true;

	perf_evlist__for_each_evsel(evlist, evsel)
		__perf_evlist__propagate_maps(evlist, evsel);
}

void perf_evlist__add(struct perf_evlist *evlist,
		      struct perf_evsel *evsel)
{
	evsel->idx = evlist->nr_entries;
	list_add_tail(&evsel->node, &evlist->entries);
	evlist->nr_entries += 1;

	if (evlist->needs_map_propagation)
		__perf_evlist__propagate_maps(evlist, evsel);
}

void perf_evlist__remove(struct perf_evlist *evlist,
			 struct perf_evsel *evsel)
{
	list_del_init(&evsel->node);
	evlist->nr_entries -= 1;
}

struct perf_evlist *perf_evlist__new(void)
{
	struct perf_evlist *evlist = zalloc(sizeof(*evlist));

	if (evlist != NULL)
		perf_evlist__init(evlist);

	return evlist;
}

struct perf_evsel *
perf_evlist__next(struct perf_evlist *evlist, struct perf_evsel *prev)
{
	struct perf_evsel *next;

	if (!prev) {
		next = list_first_entry(&evlist->entries,
					struct perf_evsel,
					node);
	} else {
		next = list_next_entry(prev, node);
	}

	/* Empty list is noticed here so don't need checking on entry. */
	if (&next->node == &evlist->entries)
		return NULL;

	return next;
}

static void perf_evlist__purge(struct perf_evlist *evlist)
{
	struct perf_evsel *pos, *n;

	perf_evlist__for_each_entry_safe(evlist, n, pos) {
		list_del_init(&pos->node);
		perf_evsel__delete(pos);
	}

	evlist->nr_entries = 0;
}

void perf_evlist__exit(struct perf_evlist *evlist)
{
	perf_cpu_map__put(evlist->user_requested_cpus);
	perf_cpu_map__put(evlist->all_cpus);
	perf_thread_map__put(evlist->threads);
	evlist->user_requested_cpus = NULL;
	evlist->all_cpus = NULL;
	evlist->threads = NULL;
	fdarray__exit(&evlist->pollfd);
}

void perf_evlist__delete(struct perf_evlist *evlist)
{
	if (evlist == NULL)
		return;

	perf_evlist__munmap(evlist);
	perf_evlist__close(evlist);
	perf_evlist__purge(evlist);
	perf_evlist__exit(evlist);
	free(evlist);
}

void perf_evlist__set_maps(struct perf_evlist *evlist,
			   struct perf_cpu_map *cpus,
			   struct perf_thread_map *threads)
{
	/*
	 * Allow for the possibility that one or another of the maps isn't being
	 * changed i.e. don't put it.  Note we are assuming the maps that are
	 * being applied are brand new and evlist is taking ownership of the
	 * original reference count of 1.  If that is not the case it is up to
	 * the caller to increase the reference count.
	 */
	if (cpus != evlist->user_requested_cpus) {
		perf_cpu_map__put(evlist->user_requested_cpus);
		evlist->user_requested_cpus = perf_cpu_map__get(cpus);
	}

	if (threads != evlist->threads) {
		perf_thread_map__put(evlist->threads);
		evlist->threads = perf_thread_map__get(threads);
	}

	perf_evlist__propagate_maps(evlist);
}

int perf_evlist__open(struct perf_evlist *evlist)
{
	struct perf_evsel *evsel;
	int err;

	perf_evlist__for_each_entry(evlist, evsel) {
		err = perf_evsel__open(evsel, evsel->cpus, evsel->threads);
		if (err < 0)
			goto out_err;
	}

	return 0;

out_err:
	perf_evlist__close(evlist);
	return err;
}

void perf_evlist__close(struct perf_evlist *evlist)
{
	struct perf_evsel *evsel;

	perf_evlist__for_each_entry_reverse(evlist, evsel)
		perf_evsel__close(evsel);
}

void perf_evlist__enable(struct perf_evlist *evlist)
{
	struct perf_evsel *evsel;

	perf_evlist__for_each_entry(evlist, evsel)
		perf_evsel__enable(evsel);
}

void perf_evlist__disable(struct perf_evlist *evlist)
{
	struct perf_evsel *evsel;

	perf_evlist__for_each_entry(evlist, evsel)
		perf_evsel__disable(evsel);
}

u64 perf_evlist__read_format(struct perf_evlist *evlist)
{
	struct perf_evsel *first = perf_evlist__first(evlist);

	return first->attr.read_format;
}

#define SID(e, x, y) xyarray__entry(e->sample_id, x, y)

static void perf_evlist__id_hash(struct perf_evlist *evlist,
				 struct perf_evsel *evsel,
				 int cpu, int thread, u64 id)
{
	int hash;
	struct perf_sample_id *sid = SID(evsel, cpu, thread);

	sid->id = id;
	sid->evsel = evsel;
	hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
	hlist_add_head(&sid->node, &evlist->heads[hash]);
}

void perf_evlist__reset_id_hash(struct perf_evlist *evlist)
{
	int i;

	for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
		INIT_HLIST_HEAD(&evlist->heads[i]);
}

void perf_evlist__id_add(struct perf_evlist *evlist,
			 struct perf_evsel *evsel,
			 int cpu, int thread, u64 id)
{
	perf_evlist__id_hash(evlist, evsel, cpu, thread, id);
	evsel->id[evsel->ids++] = id;
}

int perf_evlist__id_add_fd(struct perf_evlist *evlist,
			   struct perf_evsel *evsel,
			   int cpu, int thread, int fd)
{
	u64 read_data[4] = { 0, };
	int id_idx = 1; /* The first entry is the counter value */
	u64 id;
	int ret;

	ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
	if (!ret)
		goto add;

	if (errno != ENOTTY)
		return -1;

	/* Legacy way to get event id.. All hail to old kernels! */

	/*
	 * This way does not work with group format read, so bail
	 * out in that case.
	 */
	if (perf_evlist__read_format(evlist) & PERF_FORMAT_GROUP)
		return -1;

	if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
	    read(fd, &read_data, sizeof(read_data)) == -1)
		return -1;

	if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
		++id_idx;
	if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
		++id_idx;

	id = read_data[id_idx];

add:
	perf_evlist__id_add(evlist, evsel, cpu, thread, id);
	return 0;
}

int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
{
	int nr_cpus = perf_cpu_map__nr(evlist->all_cpus);
	int nr_threads = perf_thread_map__nr(evlist->threads);
	int nfds = 0;
	struct perf_evsel *evsel;

	perf_evlist__for_each_entry(evlist, evsel) {
		if (evsel->system_wide)
			nfds += nr_cpus;
		else
			nfds += nr_cpus * nr_threads;
	}

	if (fdarray__available_entries(&evlist->pollfd) < nfds &&
	    fdarray__grow(&evlist->pollfd, nfds) < 0)
		return -ENOMEM;

	return 0;
}

int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd,
			    void *ptr, short revent, enum fdarray_flags flags)
{
	int pos = fdarray__add(&evlist->pollfd, fd, revent | POLLERR | POLLHUP, flags);

	if (pos >= 0) {
		evlist->pollfd.priv[pos].ptr = ptr;
		fcntl(fd, F_SETFL, O_NONBLOCK);
	}

	return pos;
}

static void perf_evlist__munmap_filtered(struct fdarray *fda, int fd,
					 void *arg __maybe_unused)
{
	struct perf_mmap *map = fda->priv[fd].ptr;

	if (map)
		perf_mmap__put(map);
}

int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask)
{
	return fdarray__filter(&evlist->pollfd, revents_and_mask,
			       perf_evlist__munmap_filtered, NULL);
}

int perf_evlist__poll(struct perf_evlist *evlist, int timeout)
{
	return fdarray__poll(&evlist->pollfd, timeout);
}

static struct perf_mmap* perf_evlist__alloc_mmap(struct perf_evlist *evlist, bool overwrite)
{
	int i;
	struct perf_mmap *map;

	map = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
	if (!map)
		return NULL;

	for (i = 0; i < evlist->nr_mmaps; i++) {
		struct perf_mmap *prev = i ? &map[i - 1] : NULL;

		/*
		 * When the perf_mmap() call is made we grab one refcount, plus
		 * one extra to let perf_mmap__consume() get the last
		 * events after all real references (perf_mmap__get()) are
		 * dropped.
		 *
		 * Each PERF_EVENT_IOC_SET_OUTPUT points to this mmap and
		 * thus does perf_mmap__get() on it.
		 */
		perf_mmap__init(&map[i], prev, overwrite, NULL);
	}

	return map;
}

static void perf_evsel__set_sid_idx(struct perf_evsel *evsel, int idx, int cpu, int thread)
{
	struct perf_sample_id *sid = SID(evsel, cpu, thread);

	sid->idx = idx;
	sid->cpu = perf_cpu_map__cpu(evsel->cpus, cpu);
	sid->tid = perf_thread_map__pid(evsel->threads, thread);
}

static struct perf_mmap*
perf_evlist__mmap_cb_get(struct perf_evlist *evlist, bool overwrite, int idx)
{
	struct perf_mmap *maps;

	maps = overwrite ? evlist->mmap_ovw : evlist->mmap;

	if (!maps) {
		maps = perf_evlist__alloc_mmap(evlist, overwrite);
		if (!maps)
			return NULL;

		if (overwrite)
			evlist->mmap_ovw = maps;
		else
			evlist->mmap = maps;
	}

	return &maps[idx];
}

#define FD(e, x, y) (*(int *) xyarray__entry(e->fd, x, y))

static int
perf_evlist__mmap_cb_mmap(struct perf_mmap *map, struct perf_mmap_param *mp,
			  int output, struct perf_cpu cpu)
{
	return perf_mmap__mmap(map, mp, output, cpu);
}

static void perf_evlist__set_mmap_first(struct perf_evlist *evlist, struct perf_mmap *map,
					bool overwrite)
{
	if (overwrite)
		evlist->mmap_ovw_first = map;
	else
		evlist->mmap_first = map;
}

static int
mmap_per_evsel(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
	       int idx, struct perf_mmap_param *mp, int cpu_idx,
	       int thread, int *_output, int *_output_overwrite, int *nr_mmaps)
{
	struct perf_cpu evlist_cpu = perf_cpu_map__cpu(evlist->all_cpus, cpu_idx);
	struct perf_evsel *evsel;
	int revent;

	perf_evlist__for_each_entry(evlist, evsel) {
		bool overwrite = evsel->attr.write_backward;
		enum fdarray_flags flgs;
		struct perf_mmap *map;
		int *output, fd, cpu;

		if (evsel->system_wide && thread)
			continue;

		cpu = perf_cpu_map__idx(evsel->cpus, evlist_cpu);
		if (cpu == -1)
			continue;

		map = ops->get(evlist, overwrite, idx);
		if (map == NULL)
			return -ENOMEM;

		if (overwrite) {
			mp->prot = PROT_READ;
			output   = _output_overwrite;
		} else {
			mp->prot = PROT_READ | PROT_WRITE;
			output   = _output;
		}

		fd = FD(evsel, cpu, thread);

		if (*output == -1) {
			*output = fd;

			/*
			 * The last one will be done at perf_mmap__consume(), so that we
			 * make sure we don't prevent tools from consuming every last event in
			 * the ring buffer.
			 *
			 * I.e. we can get the POLLHUP meaning that the fd doesn't exist
			 * anymore, but the last events for it are still in the ring buffer,
			 * waiting to be consumed.
			 *
			 * Tools can chose to ignore this at their own discretion, but the
			 * evlist layer can't just drop it when filtering events in
			 * perf_evlist__filter_pollfd().
			 */
			refcount_set(&map->refcnt, 2);

			if (ops->idx)
				ops->idx(evlist, evsel, mp, idx);

			/* Debug message used by test scripts */
			pr_debug("idx %d: mmapping fd %d\n", idx, *output);
			if (ops->mmap(map, mp, *output, evlist_cpu) < 0)
				return -1;

			*nr_mmaps += 1;

			if (!idx)
				perf_evlist__set_mmap_first(evlist, map, overwrite);
		} else {
			/* Debug message used by test scripts */
			pr_debug("idx %d: set output fd %d -> %d\n", idx, fd, *output);
			if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
				return -1;

			perf_mmap__get(map);
		}

		revent = !overwrite ? POLLIN : 0;

		flgs = evsel->system_wide ? fdarray_flag__nonfilterable : fdarray_flag__default;
		if (perf_evlist__add_pollfd(evlist, fd, map, revent, flgs) < 0) {
			perf_mmap__put(map);
			return -1;
		}

		if (evsel->attr.read_format & PERF_FORMAT_ID) {
			if (perf_evlist__id_add_fd(evlist, evsel, cpu, thread,
						   fd) < 0)
				return -1;
			perf_evsel__set_sid_idx(evsel, idx, cpu, thread);
		}
	}

	return 0;
}

static int
mmap_per_thread(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
		struct perf_mmap_param *mp)
{
	int nr_threads = perf_thread_map__nr(evlist->threads);
	int nr_cpus    = perf_cpu_map__nr(evlist->all_cpus);
	int cpu, thread, idx = 0;
	int nr_mmaps = 0;

	pr_debug("%s: nr cpu values (may include -1) %d nr threads %d\n",
		 __func__, nr_cpus, nr_threads);

	/* per-thread mmaps */
	for (thread = 0; thread < nr_threads; thread++, idx++) {
		int output = -1;
		int output_overwrite = -1;

		if (mmap_per_evsel(evlist, ops, idx, mp, 0, thread, &output,
				   &output_overwrite, &nr_mmaps))
			goto out_unmap;
	}

	/* system-wide mmaps i.e. per-cpu */
	for (cpu = 1; cpu < nr_cpus; cpu++, idx++) {
		int output = -1;
		int output_overwrite = -1;

		if (mmap_per_evsel(evlist, ops, idx, mp, cpu, 0, &output,
				   &output_overwrite, &nr_mmaps))
			goto out_unmap;
	}

	if (nr_mmaps != evlist->nr_mmaps)
		pr_err("Miscounted nr_mmaps %d vs %d\n", nr_mmaps, evlist->nr_mmaps);

	return 0;

out_unmap:
	perf_evlist__munmap(evlist);
	return -1;
}

static int
mmap_per_cpu(struct perf_evlist *evlist, struct perf_evlist_mmap_ops *ops,
	     struct perf_mmap_param *mp)
{
	int nr_threads = perf_thread_map__nr(evlist->threads);
	int nr_cpus    = perf_cpu_map__nr(evlist->all_cpus);
	int nr_mmaps = 0;
	int cpu, thread;

	pr_debug("%s: nr cpu values %d nr threads %d\n", __func__, nr_cpus, nr_threads);

	for (cpu = 0; cpu < nr_cpus; cpu++) {
		int output = -1;
		int output_overwrite = -1;

		for (thread = 0; thread < nr_threads; thread++) {
			if (mmap_per_evsel(evlist, ops, cpu, mp, cpu,
					   thread, &output, &output_overwrite, &nr_mmaps))
				goto out_unmap;
		}
	}

	if (nr_mmaps != evlist->nr_mmaps)
		pr_err("Miscounted nr_mmaps %d vs %d\n", nr_mmaps, evlist->nr_mmaps);

	return 0;

out_unmap:
	perf_evlist__munmap(evlist);
	return -1;
}

static int perf_evlist__nr_mmaps(struct perf_evlist *evlist)
{
	int nr_mmaps;

	/* One for each CPU */
	nr_mmaps = perf_cpu_map__nr(evlist->all_cpus);
	if (perf_cpu_map__empty(evlist->all_cpus)) {
		/* Plus one for each thread */
		nr_mmaps += perf_thread_map__nr(evlist->threads);
		/* Minus the per-thread CPU (-1) */
		nr_mmaps -= 1;
	}

	return nr_mmaps;
}

int perf_evlist__mmap_ops(struct perf_evlist *evlist,
			  struct perf_evlist_mmap_ops *ops,
			  struct perf_mmap_param *mp)
{
	const struct perf_cpu_map *cpus = evlist->all_cpus;
	struct perf_evsel *evsel;

	if (!ops || !ops->get || !ops->mmap)
		return -EINVAL;

	mp->mask = evlist->mmap_len - page_size - 1;

	evlist->nr_mmaps = perf_evlist__nr_mmaps(evlist);

	perf_evlist__for_each_entry(evlist, evsel) {
		if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
		    evsel->sample_id == NULL &&
		    perf_evsel__alloc_id(evsel, evsel->fd->max_x, evsel->fd->max_y) < 0)
			return -ENOMEM;
	}

	if (evlist->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
		return -ENOMEM;

	if (perf_cpu_map__empty(cpus))
		return mmap_per_thread(evlist, ops, mp);

	return mmap_per_cpu(evlist, ops, mp);
}

int perf_evlist__mmap(struct perf_evlist *evlist, int pages)
{
	struct perf_mmap_param mp;
	struct perf_evlist_mmap_ops ops = {
		.get  = perf_evlist__mmap_cb_get,
		.mmap = perf_evlist__mmap_cb_mmap,
	};

	evlist->mmap_len = (pages + 1) * page_size;

	return perf_evlist__mmap_ops(evlist, &ops, &mp);
}

void perf_evlist__munmap(struct perf_evlist *evlist)
{
	int i;

	if (evlist->mmap) {
		for (i = 0; i < evlist->nr_mmaps; i++)
			perf_mmap__munmap(&evlist->mmap[i]);
	}

	if (evlist->mmap_ovw) {
		for (i = 0; i < evlist->nr_mmaps; i++)
			perf_mmap__munmap(&evlist->mmap_ovw[i]);
	}

	zfree(&evlist->mmap);
	zfree(&evlist->mmap_ovw);
}

struct perf_mmap*
perf_evlist__next_mmap(struct perf_evlist *evlist, struct perf_mmap *map,
		       bool overwrite)
{
	if (map)
		return map->next;

	return overwrite ? evlist->mmap_ovw_first : evlist->mmap_first;
}

void __perf_evlist__set_leader(struct list_head *list, struct perf_evsel *leader)
{
	struct perf_evsel *evsel;
	int n = 0;

	__perf_evlist__for_each_entry(list, evsel) {
		evsel->leader = leader;
		n++;
	}
	leader->nr_members = n;
}

void perf_evlist__set_leader(struct perf_evlist *evlist)
{
	if (evlist->nr_entries) {
		struct perf_evsel *first = list_entry(evlist->entries.next,
						struct perf_evsel, node);

		__perf_evlist__set_leader(&evlist->entries, first);
	}
}

int perf_evlist__nr_groups(struct perf_evlist *evlist)
{
	struct perf_evsel *evsel;
	int nr_groups = 0;

	perf_evlist__for_each_evsel(evlist, evsel) {
		/*
		 * evsels by default have a nr_members of 1, and they are their
		 * own leader. If the nr_members is >1 then this is an
		 * indication of a group.
		 */
		if (evsel->leader == evsel && evsel->nr_members > 1)
			nr_groups++;
	}
	return nr_groups;
}

void perf_evlist__go_system_wide(struct perf_evlist *evlist, struct perf_evsel *evsel)
{
	if (!evsel->system_wide) {
		evsel->system_wide = true;
		if (evlist->needs_map_propagation)
			__perf_evlist__propagate_maps(evlist, evsel);
	}
}