tools/perf/util/mmap.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2011-2017, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
  *
  * Parts came from evlist.c builtin-{top,stat,record}.c, see those files for further
  * copyright notes.
  */

 #include <sys/mman.h>
 #include <inttypes.h>
 #include <asm/bug.h>
 #include <linux/zalloc.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h> // sysconf()
 #include <perf/mmap.h>
 #ifdef HAVE_LIBNUMA_SUPPORT
 #include <numaif.h>
 #endif
 #include "cpumap.h"
 #include "debug.h"
 #include "event.h"
 #include "mmap.h"
 #include "../perf.h"
 #include <internal/lib.h> /* page_size */
 #include <linux/bitmap.h>

 #define MASK_SIZE 1023
 void mmap_cpu_mask__scnprintf(struct mmap_cpu_mask *mask, const char *tag)
 {
 	char buf[MASK_SIZE + 1];
 	size_t len;

 	len = bitmap_scnprintf(mask->bits, mask->nbits, buf, MASK_SIZE);
 	buf[len] = '\0';
 	pr_debug("%p: %s mask[%zd]: %s\n", mask, tag, mask->nbits, buf);
 }

 size_t mmap__mmap_len(struct mmap *map)
 {
 	return perf_mmap__mmap_len(&map->core);
 }

 int __weak auxtrace_mmap__mmap(struct auxtrace_mmap *mm __maybe_unused,
 			       struct auxtrace_mmap_params *mp __maybe_unused,
 			       void *userpg __maybe_unused,
 			       int fd __maybe_unused)
 {
 	return 0;
 }

 void __weak auxtrace_mmap__munmap(struct auxtrace_mmap *mm __maybe_unused)
 {
 }

 void __weak auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp __maybe_unused,
 				       off_t auxtrace_offset __maybe_unused,
 				       unsigned int auxtrace_pages __maybe_unused,
 				       bool auxtrace_overwrite __maybe_unused)
 {
 }

 void __weak auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp __maybe_unused,
 					  struct evlist *evlist __maybe_unused,
 					  struct evsel *evsel __maybe_unused,
 					  int idx __maybe_unused)
 {
 }

 #ifdef HAVE_AIO_SUPPORT
 static int perf_mmap__aio_enabled(struct mmap *map)
 {
 	return map->aio.nr_cblocks > 0;
 }

 #ifdef HAVE_LIBNUMA_SUPPORT
 static int perf_mmap__aio_alloc(struct mmap *map, int idx)
 {
 	map->aio.data[idx] = mmap(NULL, mmap__mmap_len(map), PROT_READ|PROT_WRITE,
 				  MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
 	if (map->aio.data[idx] == MAP_FAILED) {
 		map->aio.data[idx] = NULL;
 		return -1;
 	}

 	return 0;
 }

 static void perf_mmap__aio_free(struct mmap *map, int idx)
 {
 	if (map->aio.data[idx]) {
 		munmap(map->aio.data[idx], mmap__mmap_len(map));
 		map->aio.data[idx] = NULL;
 	}
 }

 static int perf_mmap__aio_bind(struct mmap *map, int idx, struct perf_cpu cpu, int affinity)
 {
 	void *data;
 	size_t mmap_len;
 	unsigned long *node_mask;
 	unsigned long node_index;
 	int err = 0;

 	if (affinity != PERF_AFFINITY_SYS && cpu__max_node() > 1) {
 		data = map->aio.data[idx];
 		mmap_len = mmap__mmap_len(map);
 		node_index = cpu__get_node(cpu);
 		node_mask = bitmap_zalloc(node_index + 1);
 		if (!node_mask) {
 			pr_err("Failed to allocate node mask for mbind: error %m\n");
 			return -1;
 		}
 		set_bit(node_index, node_mask);
 		if (mbind(data, mmap_len, MPOL_BIND, node_mask, node_index + 1 + 1, 0)) {
 			pr_err("Failed to bind [%p-%p] AIO buffer to node %lu: error %m\n",
 				data, data + mmap_len, node_index);
 			err = -1;
 		}
 		bitmap_free(node_mask);
 	}

 	return err;
 }
 #else /* !HAVE_LIBNUMA_SUPPORT */
 static int perf_mmap__aio_alloc(struct mmap *map, int idx)
 {
 	map->aio.data[idx] = malloc(mmap__mmap_len(map));
 	if (map->aio.data[idx] == NULL)
 		return -1;

 	return 0;
 }

 static void perf_mmap__aio_free(struct mmap *map, int idx)
 {
 	zfree(&(map->aio.data[idx]));
 }

 static int perf_mmap__aio_bind(struct mmap *map __maybe_unused, int idx __maybe_unused,
 		struct perf_cpu cpu __maybe_unused, int affinity __maybe_unused)
 {
 	return 0;
 }
 #endif

 static int perf_mmap__aio_mmap(struct mmap *map, struct mmap_params *mp)
 {
 	int delta_max, i, prio, ret;

 	map->aio.nr_cblocks = mp->nr_cblocks;
 	if (map->aio.nr_cblocks) {
 		map->aio.aiocb = calloc(map->aio.nr_cblocks, sizeof(struct aiocb *));
 		if (!map->aio.aiocb) {
 			pr_debug2("failed to allocate aiocb for data buffer, error %m\n");
 			return -1;
 		}
 		map->aio.cblocks = calloc(map->aio.nr_cblocks, sizeof(struct aiocb));
 		if (!map->aio.cblocks) {
 			pr_debug2("failed to allocate cblocks for data buffer, error %m\n");
 			return -1;
 		}
 		map->aio.data = calloc(map->aio.nr_cblocks, sizeof(void *));
 		if (!map->aio.data) {
 			pr_debug2("failed to allocate data buffer, error %m\n");
 			return -1;
 		}
 		delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX);
 		for (i = 0; i < map->aio.nr_cblocks; ++i) {
 			ret = perf_mmap__aio_alloc(map, i);
 			if (ret == -1) {
 				pr_debug2("failed to allocate data buffer area, error %m");
 				return -1;
 			}
 			ret = perf_mmap__aio_bind(map, i, map->core.cpu, mp->affinity);
 			if (ret == -1)
 				return -1;
 			/*
 			 * Use cblock.aio_fildes value different from -1
 			 * to denote started aio write operation on the
 			 * cblock so it requires explicit record__aio_sync()
 			 * call prior the cblock may be reused again.
 			 */
 			map->aio.cblocks[i].aio_fildes = -1;
 			/*
 			 * Allocate cblocks with priority delta to have
 			 * faster aio write system calls because queued requests
 			 * are kept in separate per-prio queues and adding
 			 * a new request will iterate thru shorter per-prio
 			 * list. Blocks with numbers higher than
 			 *  _SC_AIO_PRIO_DELTA_MAX go with priority 0.
 			 */
 			prio = delta_max - i;
 			map->aio.cblocks[i].aio_reqprio = prio >= 0 ? prio : 0;
 		}
 	}

 	return 0;
 }

 static void perf_mmap__aio_munmap(struct mmap *map)
 {
 	int i;

 	for (i = 0; i < map->aio.nr_cblocks; ++i)
 		perf_mmap__aio_free(map, i);
 	if (map->aio.data)
 		zfree(&map->aio.data);
 	zfree(&map->aio.cblocks);
 	zfree(&map->aio.aiocb);
 }
 #else /* !HAVE_AIO_SUPPORT */
 static int perf_mmap__aio_enabled(struct mmap *map __maybe_unused)
 {
 	return 0;
 }

 static int perf_mmap__aio_mmap(struct mmap *map __maybe_unused,
 			       struct mmap_params *mp __maybe_unused)
 {
 	return 0;
 }

 static void perf_mmap__aio_munmap(struct mmap *map __maybe_unused)
 {
 }
 #endif

 void mmap__munmap(struct mmap *map)
 {
 	bitmap_free(map->affinity_mask.bits);

 #ifndef PYTHON_PERF
 	zstd_fini(&map->zstd_data);
 #endif

 	perf_mmap__aio_munmap(map);
 	if (map->data != NULL) {
 		munmap(map->data, mmap__mmap_len(map));
 		map->data = NULL;
 	}
 	auxtrace_mmap__munmap(&map->auxtrace_mmap);
 }

 static void build_node_mask(int node, struct mmap_cpu_mask *mask)
 {
 	int idx, nr_cpus;
 	struct perf_cpu cpu;
 	const struct perf_cpu_map *cpu_map = NULL;

 	cpu_map = cpu_map__online();
 	if (!cpu_map)
 		return;

 	nr_cpus = perf_cpu_map__nr(cpu_map);
 	for (idx = 0; idx < nr_cpus; idx++) {
 		cpu = perf_cpu_map__cpu(cpu_map, idx); /* map c index to online cpu index */
 		if (cpu__get_node(cpu) == node)
 			set_bit(cpu.cpu, mask->bits);
 	}
 }

 static int perf_mmap__setup_affinity_mask(struct mmap *map, struct mmap_params *mp)
 {
 	map->affinity_mask.nbits = cpu__max_cpu().cpu;
 	map->affinity_mask.bits = bitmap_zalloc(map->affinity_mask.nbits);
 	if (!map->affinity_mask.bits)
 		return -1;

 	if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1)
 		build_node_mask(cpu__get_node(map->core.cpu), &map->affinity_mask);
 	else if (mp->affinity == PERF_AFFINITY_CPU)
 		set_bit(map->core.cpu.cpu, map->affinity_mask.bits);

 	return 0;
 }

 int mmap__mmap(struct mmap *map, struct mmap_params *mp, int fd, struct perf_cpu cpu)
 {
 	if (perf_mmap__mmap(&map->core, &mp->core, fd, cpu)) {
 		pr_debug2("failed to mmap perf event ring buffer, error %d\n",
 			  errno);
 		return -1;
 	}

 	if (mp->affinity != PERF_AFFINITY_SYS &&
 		perf_mmap__setup_affinity_mask(map, mp)) {
 		pr_debug2("failed to alloc mmap affinity mask, error %d\n",
 			  errno);
 		return -1;
 	}

 	if (verbose == 2)
 		mmap_cpu_mask__scnprintf(&map->affinity_mask, "mmap");

 	map->core.flush = mp->flush;

 	map->comp_level = mp->comp_level;
 #ifndef PYTHON_PERF
 	if (zstd_init(&map->zstd_data, map->comp_level)) {
 		pr_debug2("failed to init mmap compressor, error %d\n", errno);
 		return -1;
 	}
 #endif

 	if (map->comp_level && !perf_mmap__aio_enabled(map)) {
 		map->data = mmap(NULL, mmap__mmap_len(map), PROT_READ|PROT_WRITE,
 				 MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
 		if (map->data == MAP_FAILED) {
 			pr_debug2("failed to mmap data buffer, error %d\n",
 					errno);
 			map->data = NULL;
 			return -1;
 		}
 	}

 	if (auxtrace_mmap__mmap(&map->auxtrace_mmap,
 				&mp->auxtrace_mp, map->core.base, fd))
 		return -1;

 	return perf_mmap__aio_mmap(map, mp);
 }

 int perf_mmap__push(struct mmap *md, void *to,
 		    int push(struct mmap *map, void *to, void *buf, size_t size))
 {
 	u64 head = perf_mmap__read_head(&md->core);
 	unsigned char *data = md->core.base + page_size;
 	unsigned long size;
 	void *buf;
 	int rc = 0;

 	rc = perf_mmap__read_init(&md->core);
 	if (rc < 0)
 		return (rc == -EAGAIN) ? 1 : -1;

 	size = md->core.end - md->core.start;

 	if ((md->core.start & md->core.mask) + size != (md->core.end & md->core.mask)) {
 		buf = &data[md->core.start & md->core.mask];
 		size = md->core.mask + 1 - (md->core.start & md->core.mask);
 		md->core.start += size;

 		if (push(md, to, buf, size) < 0) {
 			rc = -1;
 			goto out;
 		}
 	}

 	buf = &data[md->core.start & md->core.mask];
 	size = md->core.end - md->core.start;
 	md->core.start += size;

 	if (push(md, to, buf, size) < 0) {
 		rc = -1;
 		goto out;
 	}

 	md->core.prev = head;
 	perf_mmap__consume(&md->core);
 out:
 	return rc;
 }

 int mmap_cpu_mask__duplicate(struct mmap_cpu_mask *original, struct mmap_cpu_mask *clone)
 {
 	clone->nbits = original->nbits;
 	clone->bits  = bitmap_zalloc(original->nbits);
 	if (!clone->bits)
 		return -ENOMEM;

 	memcpy(clone->bits, original->bits, MMAP_CPU_MASK_BYTES(original));
 	return 0;
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2011-2017, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
	*
	* Parts came from evlist.c builtin-{top,stat,record}.c, see those files for further
	* copyright notes.
	*/

	#include <sys/mman.h>
	#include <inttypes.h>
	#include <asm/bug.h>
	#include <linux/zalloc.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h> // sysconf()
	#include <perf/mmap.h>
	#ifdef HAVE_LIBNUMA_SUPPORT
	#include <numaif.h>
	#endif
	#include "cpumap.h"
	#include "debug.h"
	#include "event.h"
	#include "mmap.h"
	#include "../perf.h"
	#include <internal/lib.h> /* page_size */
	#include <linux/bitmap.h>

	#define MASK_SIZE 1023
	void mmap_cpu_mask__scnprintf(struct mmap_cpu_mask mask, const char tag)
	{
	char buf[MASK_SIZE + 1];
	size_t len;

	len = bitmap_scnprintf(mask->bits, mask->nbits, buf, MASK_SIZE);
	buf[len] = '\0';
	pr_debug("%p: %s mask[%zd]: %s\n", mask, tag, mask->nbits, buf);
	}

	size_t mmap__mmap_len(struct mmap *map)
	{
	return perf_mmap__mmap_len(&map->core);
	}

	int __weak auxtrace_mmap__mmap(struct auxtrace_mmap *mm __maybe_unused,
	struct auxtrace_mmap_params *mp __maybe_unused,
	void *userpg __maybe_unused,
	int fd __maybe_unused)
	{
	return 0;
	}

	void __weak auxtrace_mmap__munmap(struct auxtrace_mmap *mm __maybe_unused)
	{
	}

	void __weak auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp __maybe_unused,
	off_t auxtrace_offset __maybe_unused,
	unsigned int auxtrace_pages __maybe_unused,
	bool auxtrace_overwrite __maybe_unused)
	{
	}

	void __weak auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp __maybe_unused,
	struct evlist *evlist __maybe_unused,
	struct evsel *evsel __maybe_unused,
	int idx __maybe_unused)
	{
	}

	#ifdef HAVE_AIO_SUPPORT
	static int perf_mmap__aio_enabled(struct mmap *map)
	{
	return map->aio.nr_cblocks > 0;
	}

	#ifdef HAVE_LIBNUMA_SUPPORT
	static int perf_mmap__aio_alloc(struct mmap *map, int idx)
	{
	map->aio.data[idx] = mmap(NULL, mmap__mmap_len(map), PROT_READ\|PROT_WRITE,
	MAP_PRIVATE\|MAP_ANONYMOUS, 0, 0);
	if (map->aio.data[idx] == MAP_FAILED) {
	map->aio.data[idx] = NULL;
	return -1;
	}

	return 0;
	}

	static void perf_mmap__aio_free(struct mmap *map, int idx)
	{
	if (map->aio.data[idx]) {
	munmap(map->aio.data[idx], mmap__mmap_len(map));
	map->aio.data[idx] = NULL;
	}
	}

	static int perf_mmap__aio_bind(struct mmap *map, int idx, struct perf_cpu cpu, int affinity)
	{
	void *data;
	size_t mmap_len;
	unsigned long *node_mask;
	unsigned long node_index;
	int err = 0;

	if (affinity != PERF_AFFINITY_SYS && cpu__max_node() > 1) {
	data = map->aio.data[idx];
	mmap_len = mmap__mmap_len(map);
	node_index = cpu__get_node(cpu);
	node_mask = bitmap_zalloc(node_index + 1);
	if (!node_mask) {
	pr_err("Failed to allocate node mask for mbind: error %m\n");
	return -1;
	}
	set_bit(node_index, node_mask);
	if (mbind(data, mmap_len, MPOL_BIND, node_mask, node_index + 1 + 1, 0)) {
	pr_err("Failed to bind [%p-%p] AIO buffer to node %lu: error %m\n",
	data, data + mmap_len, node_index);
	err = -1;
	}
	bitmap_free(node_mask);
	}

	return err;
	}
	#else /* !HAVE_LIBNUMA_SUPPORT */
	static int perf_mmap__aio_alloc(struct mmap *map, int idx)
	{
	map->aio.data[idx] = malloc(mmap__mmap_len(map));
	if (map->aio.data[idx] == NULL)
	return -1;

	return 0;
	}

	static void perf_mmap__aio_free(struct mmap *map, int idx)
	{
	zfree(&(map->aio.data[idx]));
	}

	static int perf_mmap__aio_bind(struct mmap *map __maybe_unused, int idx __maybe_unused,
	struct perf_cpu cpu __maybe_unused, int affinity __maybe_unused)
	{
	return 0;
	}
	#endif

	static int perf_mmap__aio_mmap(struct mmap map, struct mmap_params mp)
	{
	int delta_max, i, prio, ret;

	map->aio.nr_cblocks = mp->nr_cblocks;
	if (map->aio.nr_cblocks) {
	map->aio.aiocb = calloc(map->aio.nr_cblocks, sizeof(struct aiocb *));
	if (!map->aio.aiocb) {
	pr_debug2("failed to allocate aiocb for data buffer, error %m\n");
	return -1;
	}
	map->aio.cblocks = calloc(map->aio.nr_cblocks, sizeof(struct aiocb));
	if (!map->aio.cblocks) {
	pr_debug2("failed to allocate cblocks for data buffer, error %m\n");
	return -1;
	}
	map->aio.data = calloc(map->aio.nr_cblocks, sizeof(void *));
	if (!map->aio.data) {
	pr_debug2("failed to allocate data buffer, error %m\n");
	return -1;
	}
	delta_max = sysconf(_SC_AIO_PRIO_DELTA_MAX);
	for (i = 0; i < map->aio.nr_cblocks; ++i) {
	ret = perf_mmap__aio_alloc(map, i);
	if (ret == -1) {
	pr_debug2("failed to allocate data buffer area, error %m");
	return -1;
	}
	ret = perf_mmap__aio_bind(map, i, map->core.cpu, mp->affinity);
	if (ret == -1)
	return -1;
	/*
	* Use cblock.aio_fildes value different from -1
	* to denote started aio write operation on the
	* cblock so it requires explicit record__aio_sync()
	* call prior the cblock may be reused again.
	*/
	map->aio.cblocks[i].aio_fildes = -1;
	/*
	* Allocate cblocks with priority delta to have
	* faster aio write system calls because queued requests
	* are kept in separate per-prio queues and adding
	* a new request will iterate thru shorter per-prio
	* list. Blocks with numbers higher than
	* _SC_AIO_PRIO_DELTA_MAX go with priority 0.
	*/
	prio = delta_max - i;
	map->aio.cblocks[i].aio_reqprio = prio >= 0 ? prio : 0;
	}
	}

	return 0;
	}

	static void perf_mmap__aio_munmap(struct mmap *map)
	{
	int i;

	for (i = 0; i < map->aio.nr_cblocks; ++i)
	perf_mmap__aio_free(map, i);
	if (map->aio.data)
	zfree(&map->aio.data);
	zfree(&map->aio.cblocks);
	zfree(&map->aio.aiocb);
	}
	#else /* !HAVE_AIO_SUPPORT */
	static int perf_mmap__aio_enabled(struct mmap *map __maybe_unused)
	{
	return 0;
	}

	static int perf_mmap__aio_mmap(struct mmap *map __maybe_unused,
	struct mmap_params *mp __maybe_unused)
	{
	return 0;
	}

	static void perf_mmap__aio_munmap(struct mmap *map __maybe_unused)
	{
	}
	#endif

	void mmap__munmap(struct mmap *map)
	{
	bitmap_free(map->affinity_mask.bits);

	#ifndef PYTHON_PERF
	zstd_fini(&map->zstd_data);
	#endif

	perf_mmap__aio_munmap(map);
	if (map->data != NULL) {
	munmap(map->data, mmap__mmap_len(map));
	map->data = NULL;
	}
	auxtrace_mmap__munmap(&map->auxtrace_mmap);
	}

	static void build_node_mask(int node, struct mmap_cpu_mask *mask)
	{
	int idx, nr_cpus;
	struct perf_cpu cpu;
	const struct perf_cpu_map *cpu_map = NULL;

	cpu_map = cpu_map__online();
	if (!cpu_map)
	return;

	nr_cpus = perf_cpu_map__nr(cpu_map);
	for (idx = 0; idx < nr_cpus; idx++) {
	cpu = perf_cpu_map__cpu(cpu_map, idx); /* map c index to online cpu index */
	if (cpu__get_node(cpu) == node)
	set_bit(cpu.cpu, mask->bits);
	}
	}

	static int perf_mmap__setup_affinity_mask(struct mmap map, struct mmap_params mp)
	{
	map->affinity_mask.nbits = cpu__max_cpu().cpu;
	map->affinity_mask.bits = bitmap_zalloc(map->affinity_mask.nbits);
	if (!map->affinity_mask.bits)
	return -1;

	if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1)
	build_node_mask(cpu__get_node(map->core.cpu), &map->affinity_mask);
	else if (mp->affinity == PERF_AFFINITY_CPU)
	set_bit(map->core.cpu.cpu, map->affinity_mask.bits);

	return 0;
	}

	int mmap__mmap(struct mmap map, struct mmap_params mp, int fd, struct perf_cpu cpu)
	{
	if (perf_mmap__mmap(&map->core, &mp->core, fd, cpu)) {
	pr_debug2("failed to mmap perf event ring buffer, error %d\n",
	errno);
	return -1;
	}

	if (mp->affinity != PERF_AFFINITY_SYS &&
	perf_mmap__setup_affinity_mask(map, mp)) {
	pr_debug2("failed to alloc mmap affinity mask, error %d\n",
	errno);
	return -1;
	}

	if (verbose == 2)
	mmap_cpu_mask__scnprintf(&map->affinity_mask, "mmap");

	map->core.flush = mp->flush;

	map->comp_level = mp->comp_level;
	#ifndef PYTHON_PERF
	if (zstd_init(&map->zstd_data, map->comp_level)) {
	pr_debug2("failed to init mmap compressor, error %d\n", errno);
	return -1;
	}
	#endif

	if (map->comp_level && !perf_mmap__aio_enabled(map)) {
	map->data = mmap(NULL, mmap__mmap_len(map), PROT_READ\|PROT_WRITE,
	MAP_PRIVATE\|MAP_ANONYMOUS, 0, 0);
	if (map->data == MAP_FAILED) {
	pr_debug2("failed to mmap data buffer, error %d\n",
	errno);
	map->data = NULL;
	return -1;
	}
	}

	if (auxtrace_mmap__mmap(&map->auxtrace_mmap,
	&mp->auxtrace_mp, map->core.base, fd))
	return -1;

	return perf_mmap__aio_mmap(map, mp);
	}

	int perf_mmap__push(struct mmap md, void to,
	int push(struct mmap map, void to, void *buf, size_t size))
	{
	u64 head = perf_mmap__read_head(&md->core);
	unsigned char *data = md->core.base + page_size;
	unsigned long size;
	void *buf;
	int rc = 0;

	rc = perf_mmap__read_init(&md->core);
	if (rc < 0)
	return (rc == -EAGAIN) ? 1 : -1;

	size = md->core.end - md->core.start;

	if ((md->core.start & md->core.mask) + size != (md->core.end & md->core.mask)) {
	buf = &data[md->core.start & md->core.mask];
	size = md->core.mask + 1 - (md->core.start & md->core.mask);
	md->core.start += size;

	if (push(md, to, buf, size) < 0) {
	rc = -1;
	goto out;
	}
	}

	buf = &data[md->core.start & md->core.mask];
	size = md->core.end - md->core.start;
	md->core.start += size;

	if (push(md, to, buf, size) < 0) {
	rc = -1;
	goto out;
	}

	md->core.prev = head;
	perf_mmap__consume(&md->core);
	out:
	return rc;
	}

	int mmap_cpu_mask__duplicate(struct mmap_cpu_mask original, struct mmap_cpu_mask clone)
	{
	clone->nbits = original->nbits;
	clone->bits = bitmap_zalloc(original->nbits);
	if (!clone->bits)
	return -ENOMEM;

	memcpy(clone->bits, original->bits, MMAP_CPU_MASK_BYTES(original));
	return 0;
	}