[lttng-modules.git] / lttng-context-perf-counters.c

/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
 *
 * lttng-context-perf-counters.c
 *
 * LTTng performance monitoring counters (perf-counters) integration module.
 *
 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/perf_event.h>
#include <linux/list.h>
#include <linux/string.h>
#include <linux/cpu.h>
#include <lttng-events.h>
#include <wrapper/ringbuffer/frontend_types.h>
#include <wrapper/cpu.h>
#include <wrapper/vmalloc.h>
#include <wrapper/perf.h>
#include <lttng-tracer.h>

static
size_t perf_counter_get_size(size_t offset)
{
	size_t size = 0;

	size += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
	size += sizeof(uint64_t);
	return size;
}

static
void perf_counter_record(struct lttng_ctx_field *field,
			 struct lib_ring_buffer_ctx *ctx,
			 struct lttng_channel *chan)
{
	struct perf_event *event;
	uint64_t value;

	event = field->u.perf_counter->e[ctx->cpu];
	if (likely(event)) {
		if (unlikely(event->state == PERF_EVENT_STATE_ERROR)) {
			value = 0;
		} else {
			event->pmu->read(event);
			value = local64_read(&event->count);
		}
	} else {
		/*
		 * Perf chooses not to be clever and not to support enabling a
		 * perf counter before the cpu is brought up. Therefore, we need
		 * to support having events coming (e.g. scheduler events)
		 * before the counter is setup. Write an arbitrary 0 in this
		 * case.
		 */
		value = 0;
	}
	lib_ring_buffer_align_ctx(ctx, lttng_alignof(value));
	chan->ops->event_write(ctx, &value, sizeof(value));
}

#if defined(CONFIG_PERF_EVENTS) && (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,1,0))
static
void overflow_callback(struct perf_event *event,
		       struct perf_sample_data *data,
		       struct pt_regs *regs)
{
}
#else
static
void overflow_callback(struct perf_event *event, int nmi,
		       struct perf_sample_data *data,
		       struct pt_regs *regs)
{
}
#endif

static
void lttng_destroy_perf_counter_field(struct lttng_ctx_field *field)
{
	struct perf_event **events = field->u.perf_counter->e;

#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
	{
		int ret;

		ret = cpuhp_state_remove_instance(lttng_hp_online,
			&field->u.perf_counter->cpuhp_online.node);
		WARN_ON(ret);
		ret = cpuhp_state_remove_instance(lttng_hp_prepare,
			&field->u.perf_counter->cpuhp_prepare.node);
		WARN_ON(ret);
	}
#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
	{
		int cpu;

		lttng_cpus_read_lock();
		for_each_online_cpu(cpu)
			perf_event_release_kernel(events[cpu]);
		lttng_cpus_read_unlock();
#ifdef CONFIG_HOTPLUG_CPU
		unregister_cpu_notifier(&field->u.perf_counter->nb);
#endif
	}
#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
	kfree(field->event_field.name);
	kfree(field->u.perf_counter->attr);
	lttng_kvfree(events);
	kfree(field->u.perf_counter);
}

#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))

int lttng_cpuhp_perf_counter_online(unsigned int cpu,
		struct lttng_cpuhp_node *node)
{
	struct lttng_perf_counter_field *perf_field =
		container_of(node, struct lttng_perf_counter_field,
				cpuhp_online);
	struct perf_event **events = perf_field->e;
	struct perf_event_attr *attr = perf_field->attr;
	struct perf_event *pevent;

	pevent = wrapper_perf_event_create_kernel_counter(attr,
			cpu, NULL, overflow_callback);
	if (!pevent || IS_ERR(pevent))
		return -EINVAL;
	if (pevent->state == PERF_EVENT_STATE_ERROR) {
		perf_event_release_kernel(pevent);
		return -EINVAL;
	}
	barrier();	/* Create perf counter before setting event */
	events[cpu] = pevent;
	return 0;
}

int lttng_cpuhp_perf_counter_dead(unsigned int cpu,
		struct lttng_cpuhp_node *node)
{
	struct lttng_perf_counter_field *perf_field =
		container_of(node, struct lttng_perf_counter_field,
				cpuhp_prepare);
	struct perf_event **events = perf_field->e;
	struct perf_event *pevent;

	pevent = events[cpu];
	events[cpu] = NULL;
	barrier();	/* NULLify event before perf counter teardown */
	perf_event_release_kernel(pevent);
	return 0;
}

#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */

#ifdef CONFIG_HOTPLUG_CPU

/**
 *	lttng_perf_counter_hp_callback - CPU hotplug callback
 *	@nb: notifier block
 *	@action: hotplug action to take
 *	@hcpu: CPU number
 *
 *	Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD)
 *
 * We can setup perf counters when the cpu is online (up prepare seems to be too
 * soon).
 */
static
int lttng_perf_counter_cpu_hp_callback(struct notifier_block *nb,
						 unsigned long action,
						 void *hcpu)
{
	unsigned int cpu = (unsigned long) hcpu;
	struct lttng_perf_counter_field *perf_field =
		container_of(nb, struct lttng_perf_counter_field, nb);
	struct perf_event **events = perf_field->e;
	struct perf_event_attr *attr = perf_field->attr;
	struct perf_event *pevent;

	if (!perf_field->hp_enable)
		return NOTIFY_OK;

	switch (action) {
	case CPU_ONLINE:
	case CPU_ONLINE_FROZEN:
		pevent = wrapper_perf_event_create_kernel_counter(attr,
				cpu, NULL, overflow_callback);
		if (!pevent || IS_ERR(pevent))
			return NOTIFY_BAD;
		if (pevent->state == PERF_EVENT_STATE_ERROR) {
			perf_event_release_kernel(pevent);
			return NOTIFY_BAD;
		}
		barrier();	/* Create perf counter before setting event */
		events[cpu] = pevent;
		break;
	case CPU_UP_CANCELED:
	case CPU_UP_CANCELED_FROZEN:
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		pevent = events[cpu];
		events[cpu] = NULL;
		barrier();	/* NULLify event before perf counter teardown */
		perf_event_release_kernel(pevent);
		break;
	}
	return NOTIFY_OK;
}

#endif

#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */

int lttng_add_perf_counter_to_ctx(uint32_t type,
				  uint64_t config,
				  const char *name,
				  struct lttng_ctx **ctx)
{
	struct lttng_ctx_field *field;
	struct lttng_perf_counter_field *perf_field;
	struct perf_event **events;
	struct perf_event_attr *attr;
	int ret;
	char *name_alloc;

	events = lttng_kvzalloc(num_possible_cpus() * sizeof(*events), GFP_KERNEL);
	if (!events)
		return -ENOMEM;

	attr = kzalloc(sizeof(struct perf_event_attr), GFP_KERNEL);
	if (!attr) {
		ret = -ENOMEM;
		goto error_attr;
	}

	attr->type = type;
	attr->config = config;
	attr->size = sizeof(struct perf_event_attr);
	attr->pinned = 1;
	attr->disabled = 0;

	perf_field = kzalloc(sizeof(struct lttng_perf_counter_field), GFP_KERNEL);
	if (!perf_field) {
		ret = -ENOMEM;
		goto error_alloc_perf_field;
	}
	perf_field->e = events;
	perf_field->attr = attr;

	name_alloc = kstrdup(name, GFP_KERNEL);
	if (!name_alloc) {
		ret = -ENOMEM;
		goto name_alloc_error;
	}

	field = lttng_append_context(ctx);
	if (!field) {
		ret = -ENOMEM;
		goto append_context_error;
	}
	if (lttng_find_context(*ctx, name_alloc)) {
		ret = -EEXIST;
		goto find_error;
	}

#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))

	perf_field->cpuhp_prepare.component = LTTNG_CONTEXT_PERF_COUNTERS;
	ret = cpuhp_state_add_instance(lttng_hp_prepare,
		&perf_field->cpuhp_prepare.node);
	if (ret)
		goto cpuhp_prepare_error;

	perf_field->cpuhp_online.component = LTTNG_CONTEXT_PERF_COUNTERS;
	ret = cpuhp_state_add_instance(lttng_hp_online,
		&perf_field->cpuhp_online.node);
	if (ret)
		goto cpuhp_online_error;

#else	/* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
	{
		int cpu;

#ifdef CONFIG_HOTPLUG_CPU
		perf_field->nb.notifier_call =
			lttng_perf_counter_cpu_hp_callback;
		perf_field->nb.priority = 0;
		register_cpu_notifier(&perf_field->nb);
#endif
		lttng_cpus_read_lock();
		for_each_online_cpu(cpu) {
			events[cpu] = wrapper_perf_event_create_kernel_counter(attr,
						cpu, NULL, overflow_callback);
			if (!events[cpu] || IS_ERR(events[cpu])) {
				ret = -EINVAL;
				goto counter_error;
			}
			if (events[cpu]->state == PERF_EVENT_STATE_ERROR) {
				ret = -EBUSY;
				goto counter_busy;
			}
		}
		lttng_cpus_read_unlock();
		perf_field->hp_enable = 1;
	}
#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */

	field->destroy = lttng_destroy_perf_counter_field;

	field->event_field.name = name_alloc;
	field->event_field.type.atype = atype_integer;
	field->event_field.type.u.basic.integer.size = sizeof(uint64_t) * CHAR_BIT;
	field->event_field.type.u.basic.integer.alignment = lttng_alignof(uint64_t) * CHAR_BIT;
	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(uint64_t);
	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	field->event_field.type.u.basic.integer.base = 10;
	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
	field->get_size = perf_counter_get_size;
	field->record = perf_counter_record;
	field->u.perf_counter = perf_field;
	lttng_context_update(*ctx);

	wrapper_vmalloc_sync_mappings();
	return 0;

#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
cpuhp_online_error:
	{
		int remove_ret;

		remove_ret = cpuhp_state_remove_instance(lttng_hp_prepare,
				&perf_field->cpuhp_prepare.node);
		WARN_ON(remove_ret);
	}
cpuhp_prepare_error:
#else	/* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
counter_busy:
counter_error:
	{
		int cpu;

		for_each_online_cpu(cpu) {
			if (events[cpu] && !IS_ERR(events[cpu]))
				perf_event_release_kernel(events[cpu]);
		}
		lttng_cpus_read_unlock();
#ifdef CONFIG_HOTPLUG_CPU
		unregister_cpu_notifier(&perf_field->nb);
#endif
	}
#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
find_error:
	lttng_remove_context_field(ctx, field);
append_context_error:
	kfree(name_alloc);
name_alloc_error:
	kfree(perf_field);
error_alloc_perf_field:
	kfree(attr);
error_attr:
	lttng_kvfree(events);
	return ret;
}
Commit	Line	Data
9f36eaed MJ	1	/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
9f36eaed MJ	2	*
886d51a3	3	* lttng-context-perf-counters.c
833ad6a0 MD	4	*
	5	* LTTng performance monitoring counters (perf-counters) integration module.
	6	*
886d51a3	7	* Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
833ad6a0 MD	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/slab.h>
	12	#include <linux/perf_event.h>
	13	#include <linux/list.h>
c24a0d71	14	#include <linux/string.h>
5ca7b8a3	15	#include <linux/cpu.h>
241ae9a8 MD	16	#include <lttng-events.h>
241ae9a8 MD	17	#include <wrapper/ringbuffer/frontend_types.h>
4a6ea683	18	#include <wrapper/cpu.h>
241ae9a8 MD	19	#include <wrapper/vmalloc.h>
	20	#include <wrapper/perf.h>
	21	#include <lttng-tracer.h>
833ad6a0	22
f1676205 MD	23	static
	24	size_t perf_counter_get_size(size_t offset)
	25	{
	26	size_t size = 0;
	27
a90917c3	28	size += lib_ring_buffer_align(offset, lttng_alignof(uint64_t));
f1676205 MD	29	size += sizeof(uint64_t);
	30	return size;
	31	}
	32
833ad6a0 MD	33	static
	34	void perf_counter_record(struct lttng_ctx_field *field,
	35	struct lib_ring_buffer_ctx *ctx,
a90917c3	36	struct lttng_channel *chan)
833ad6a0 MD	37	{
	38	struct perf_event *event;
	39	uint64_t value;
	40
2001023e	41	event = field->u.perf_counter->e[ctx->cpu];
0478c519	42	if (likely(event)) {
7b745a96 MD	43	if (unlikely(event->state == PERF_EVENT_STATE_ERROR)) {
	44	value = 0;
	45	} else {
	46	event->pmu->read(event);
	47	value = local64_read(&event->count);
	48	}
f91fd73b MD	49	} else {
	50	/*
	51	* Perf chooses not to be clever and not to support enabling a
	52	* perf counter before the cpu is brought up. Therefore, we need
	53	* to support having events coming (e.g. scheduler events)
	54	* before the counter is setup. Write an arbitrary 0 in this
	55	* case.
	56	*/
	57	value = 0;
	58	}
a90917c3	59	lib_ring_buffer_align_ctx(ctx, lttng_alignof(value));
833ad6a0 MD	60	chan->ops->event_write(ctx, &value, sizeof(value));
	61	}
	62
2d042821	63	#if defined(CONFIG_PERF_EVENTS) && (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,1,0))
90f5546c MD	64	static
	65	void overflow_callback(struct perf_event *event,
	66	struct perf_sample_data *data,
	67	struct pt_regs *regs)
	68	{
	69	}
	70	#else
833ad6a0 MD	71	static
	72	void overflow_callback(struct perf_event *event, int nmi,
	73	struct perf_sample_data *data,
	74	struct pt_regs *regs)
	75	{
	76	}
90f5546c	77	#endif
833ad6a0	78
2dccf128 MD	79	static
	80	void lttng_destroy_perf_counter_field(struct lttng_ctx_field *field)
	81	{
2001023e	82	struct perf_event **events = field->u.perf_counter->e;
2dccf128	83
2d042821	84	#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
1e367326 MD	85	{
	86	int ret;
	87
	88	ret = cpuhp_state_remove_instance(lttng_hp_online,
	89	&field->u.perf_counter->cpuhp_online.node);
	90	WARN_ON(ret);
	91	ret = cpuhp_state_remove_instance(lttng_hp_prepare,
	92	&field->u.perf_counter->cpuhp_prepare.node);
	93	WARN_ON(ret);
	94	}
2d042821	95	#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
1e367326 MD	96	{
	97	int cpu;
	98
4a6ea683	99	lttng_cpus_read_lock();
1e367326 MD	100	for_each_online_cpu(cpu)
1e367326 MD	101	perf_event_release_kernel(events[cpu]);
4a6ea683	102	lttng_cpus_read_unlock();
8289661d	103	#ifdef CONFIG_HOTPLUG_CPU
1e367326	104	unregister_cpu_notifier(&field->u.perf_counter->nb);
8289661d	105	#endif
1e367326	106	}
2d042821	107	#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
c24a0d71	108	kfree(field->event_field.name);
2001023e	109	kfree(field->u.perf_counter->attr);
48f5e0b5	110	lttng_kvfree(events);
2001023e	111	kfree(field->u.perf_counter);
2dccf128 MD	112	}
2dccf128 MD	113
2d042821	114	#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
1e367326 MD	115
	116	int lttng_cpuhp_perf_counter_online(unsigned int cpu,
	117	struct lttng_cpuhp_node *node)
	118	{
	119	struct lttng_perf_counter_field *perf_field =
	120	container_of(node, struct lttng_perf_counter_field,
	121	cpuhp_online);
	122	struct perf_event **events = perf_field->e;
	123	struct perf_event_attr *attr = perf_field->attr;
	124	struct perf_event *pevent;
	125
	126	pevent = wrapper_perf_event_create_kernel_counter(attr,
	127	cpu, NULL, overflow_callback);
	128	if (!pevent \|\| IS_ERR(pevent))
	129	return -EINVAL;
	130	if (pevent->state == PERF_EVENT_STATE_ERROR) {
	131	perf_event_release_kernel(pevent);
	132	return -EINVAL;
	133	}
	134	barrier(); /* Create perf counter before setting event */
	135	events[cpu] = pevent;
	136	return 0;
	137	}
	138
	139	int lttng_cpuhp_perf_counter_dead(unsigned int cpu,
	140	struct lttng_cpuhp_node *node)
	141	{
	142	struct lttng_perf_counter_field *perf_field =
	143	container_of(node, struct lttng_perf_counter_field,
	144	cpuhp_prepare);
	145	struct perf_event **events = perf_field->e;
	146	struct perf_event *pevent;
	147
	148	pevent = events[cpu];
	149	events[cpu] = NULL;
	150	barrier(); /* NULLify event before perf counter teardown */
	151	perf_event_release_kernel(pevent);
	152	return 0;
	153	}
	154
2d042821	155	#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
1e367326	156
8289661d MD	157	#ifdef CONFIG_HOTPLUG_CPU
	158
	159	/**
	160	* lttng_perf_counter_hp_callback - CPU hotplug callback
	161	* @nb: notifier block
	162	* @action: hotplug action to take
	163	* @hcpu: CPU number
	164	*
	165	* Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD)
	166	*
	167	* We can setup perf counters when the cpu is online (up prepare seems to be too
	168	* soon).
	169	*/
	170	static
e8f071d5	171	int lttng_perf_counter_cpu_hp_callback(struct notifier_block *nb,
8289661d MD	172	unsigned long action,
	173	void *hcpu)
	174	{
	175	unsigned int cpu = (unsigned long) hcpu;
2001023e MD	176	struct lttng_perf_counter_field *perf_field =
	177	container_of(nb, struct lttng_perf_counter_field, nb);
	178	struct perf_event **events = perf_field->e;
	179	struct perf_event_attr *attr = perf_field->attr;
f91fd73b	180	struct perf_event *pevent;
8289661d	181
2001023e	182	if (!perf_field->hp_enable)
8289661d MD	183	return NOTIFY_OK;
	184
	185	switch (action) {
	186	case CPU_ONLINE:
	187	case CPU_ONLINE_FROZEN:
90f5546c	188	pevent = wrapper_perf_event_create_kernel_counter(attr,
8289661d	189	cpu, NULL, overflow_callback);
0478c519	190	if (!pevent \|\| IS_ERR(pevent))
8289661d	191	return NOTIFY_BAD;
7b745a96 MD	192	if (pevent->state == PERF_EVENT_STATE_ERROR) {
	193	perf_event_release_kernel(pevent);
	194	return NOTIFY_BAD;
	195	}
f91fd73b MD	196	barrier(); /* Create perf counter before setting event */
f91fd73b MD	197	events[cpu] = pevent;
8289661d MD	198	break;
	199	case CPU_UP_CANCELED:
	200	case CPU_UP_CANCELED_FROZEN:
	201	case CPU_DEAD:
	202	case CPU_DEAD_FROZEN:
f91fd73b MD	203	pevent = events[cpu];
	204	events[cpu] = NULL;
	205	barrier(); /* NULLify event before perf counter teardown */
	206	perf_event_release_kernel(pevent);
8289661d MD	207	break;
	208	}
	209	return NOTIFY_OK;
	210	}
	211
	212	#endif
	213
2d042821	214	#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
1e367326	215
833ad6a0 MD	216	int lttng_add_perf_counter_to_ctx(uint32_t type,
833ad6a0 MD	217	uint64_t config,
c24a0d71	218	const char *name,
2dccf128	219	struct lttng_ctx **ctx)
833ad6a0 MD	220	{
833ad6a0 MD	221	struct lttng_ctx_field *field;
2001023e	222	struct lttng_perf_counter_field *perf_field;
833ad6a0 MD	223	struct perf_event **events;
	224	struct perf_event_attr *attr;
	225	int ret;
c24a0d71	226	char *name_alloc;
833ad6a0	227
48f5e0b5	228	events = lttng_kvzalloc(num_possible_cpus() * sizeof(*events), GFP_KERNEL);
833ad6a0 MD	229	if (!events)
	230	return -ENOMEM;
	231
2001023e	232	attr = kzalloc(sizeof(struct perf_event_attr), GFP_KERNEL);
833ad6a0 MD	233	if (!attr) {
	234	ret = -ENOMEM;
	235	goto error_attr;
	236	}
	237
	238	attr->type = type;
	239	attr->config = config;
	240	attr->size = sizeof(struct perf_event_attr);
	241	attr->pinned = 1;
	242	attr->disabled = 0;
	243
2001023e MD	244	perf_field = kzalloc(sizeof(struct lttng_perf_counter_field), GFP_KERNEL);
	245	if (!perf_field) {
	246	ret = -ENOMEM;
	247	goto error_alloc_perf_field;
	248	}
	249	perf_field->e = events;
	250	perf_field->attr = attr;
	251
c24a0d71	252	name_alloc = kstrdup(name, GFP_KERNEL);
bef96e48 MD	253	if (!name_alloc) {
bef96e48 MD	254	ret = -ENOMEM;
c24a0d71	255	goto name_alloc_error;
bef96e48	256	}
c24a0d71	257
2dccf128 MD	258	field = lttng_append_context(ctx);
	259	if (!field) {
	260	ret = -ENOMEM;
8289661d	261	goto append_context_error;
833ad6a0	262	}
2001023e	263	if (lttng_find_context(*ctx, name_alloc)) {
44252f0f MD	264	ret = -EEXIST;
	265	goto find_error;
	266	}
8289661d	267
2d042821	268	#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
1e367326 MD	269
	270	perf_field->cpuhp_prepare.component = LTTNG_CONTEXT_PERF_COUNTERS;
	271	ret = cpuhp_state_add_instance(lttng_hp_prepare,
	272	&perf_field->cpuhp_prepare.node);
	273	if (ret)
	274	goto cpuhp_prepare_error;
	275
	276	perf_field->cpuhp_online.component = LTTNG_CONTEXT_PERF_COUNTERS;
	277	ret = cpuhp_state_add_instance(lttng_hp_online,
	278	&perf_field->cpuhp_online.node);
	279	if (ret)
	280	goto cpuhp_online_error;
	281
2d042821	282	#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
1e367326 MD	283	{
	284	int cpu;
	285
8289661d	286	#ifdef CONFIG_HOTPLUG_CPU
1e367326 MD	287	perf_field->nb.notifier_call =
	288	lttng_perf_counter_cpu_hp_callback;
	289	perf_field->nb.priority = 0;
	290	register_cpu_notifier(&perf_field->nb);
8289661d	291	#endif
4a6ea683	292	lttng_cpus_read_lock();
1e367326 MD	293	for_each_online_cpu(cpu) {
	294	events[cpu] = wrapper_perf_event_create_kernel_counter(attr,
	295	cpu, NULL, overflow_callback);
	296	if (!events[cpu] \|\| IS_ERR(events[cpu])) {
	297	ret = -EINVAL;
	298	goto counter_error;
	299	}
	300	if (events[cpu]->state == PERF_EVENT_STATE_ERROR) {
	301	ret = -EBUSY;
	302	goto counter_busy;
	303	}
7b745a96	304	}
4a6ea683	305	lttng_cpus_read_unlock();
1e367326	306	perf_field->hp_enable = 1;
8289661d	307	}
2d042821	308	#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
8289661d	309
2dccf128	310	field->destroy = lttng_destroy_perf_counter_field;
833ad6a0	311
c24a0d71	312	field->event_field.name = name_alloc;
8070f5c0	313	field->event_field.type.atype = atype_integer;
9d7d747f	314	field->event_field.type.u.basic.integer.size = sizeof(uint64_t) * CHAR_BIT;
a90917c3	315	field->event_field.type.u.basic.integer.alignment = lttng_alignof(uint64_t) * CHAR_BIT;
06254b0f	316	field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(uint64_t);
8070f5c0 MD	317	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	318	field->event_field.type.u.basic.integer.base = 10;
	319	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
f1676205 MD	320	field->get_size = perf_counter_get_size;
f1676205 MD	321	field->record = perf_counter_record;
2001023e	322	field->u.perf_counter = perf_field;
a9dd15da	323	lttng_context_update(*ctx);
833ad6a0	324
ea53823c	325	wrapper_vmalloc_sync_mappings();
833ad6a0 MD	326	return 0;
833ad6a0 MD	327
2d042821	328	#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
1e367326 MD	329	cpuhp_online_error:
	330	{
	331	int remove_ret;
	332
	333	remove_ret = cpuhp_state_remove_instance(lttng_hp_prepare,
	334	&perf_field->cpuhp_prepare.node);
	335	WARN_ON(remove_ret);
	336	}
	337	cpuhp_prepare_error:
2d042821	338	#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
7b745a96	339	counter_busy:
8289661d	340	counter_error:
ce4a2f0c MD	341	{
	342	int cpu;
	343
	344	for_each_online_cpu(cpu) {
	345	if (events[cpu] && !IS_ERR(events[cpu]))
	346	perf_event_release_kernel(events[cpu]);
	347	}
4a6ea683	348	lttng_cpus_read_unlock();
8289661d	349	#ifdef CONFIG_HOTPLUG_CPU
ce4a2f0c	350	unregister_cpu_notifier(&perf_field->nb);
8289661d	351	#endif
ce4a2f0c	352	}
2d042821	353	#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
44252f0f	354	find_error:
8289661d MD	355	lttng_remove_context_field(ctx, field);
	356	append_context_error:
	357	kfree(name_alloc);
	358	name_alloc_error:
2001023e MD	359	kfree(perf_field);
2001023e MD	360	error_alloc_perf_field:
833ad6a0 MD	361	kfree(attr);
833ad6a0 MD	362	error_attr:
48f5e0b5	363	lttng_kvfree(events);
833ad6a0 MD	364	return ret;
833ad6a0 MD	365	}