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

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * 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 <lttng/events-internal.h>
#include <ringbuffer/frontend_types.h>
#include <wrapper/vmalloc.h>
#include <wrapper/perf.h>
#include <lttng/tracer.h>

static
size_t perf_counter_get_size(void *priv, struct lttng_kernel_probe_ctx *probe_ctx, 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(void *priv, struct lttng_kernel_probe_ctx *probe_ctx,
			 struct lttng_kernel_ring_buffer_ctx *ctx,
			 struct lttng_channel *chan)
{
	struct lttng_perf_counter_field *perf_field = (struct lttng_perf_counter_field *) priv;
	struct perf_event *event;
	uint64_t value;

	event = perf_field->e[ctx->priv.reserve_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_ctx_field(void *priv)
{
	struct lttng_perf_counter_field *perf_field = priv;
	struct perf_event **events = perf_field->e;

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

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

		get_online_cpus();
		for_each_online_cpu(cpu)
			perf_event_release_kernel(events[cpu]);
		put_online_cpus();
#ifdef CONFIG_HOTPLUG_CPU
		unregister_cpu_notifier(&perf_field->nb);
#endif
	}
#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
	kfree(perf_field->name);
	kfree(perf_field->attr);
	kfree(perf_field->event_field);
	lttng_kvfree(events);
	kfree(perf_field);
}

#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)) */

static const struct lttng_kernel_type_common *field_type =
	lttng_kernel_static_type_integer_from_type(uint64_t, __BYTE_ORDER, 10);

int lttng_add_perf_counter_to_ctx(uint32_t type,
				  uint64_t config,
				  const char *name,
				  struct lttng_kernel_ctx **ctx)
{
	struct lttng_kernel_ctx_field ctx_field = { 0 };
	struct lttng_kernel_event_field *event_field;
	struct lttng_perf_counter_field *perf_field;
	struct perf_event **events;
	struct perf_event_attr *attr;
	int ret;
	char *name_alloc;

	if (lttng_kernel_find_context(*ctx, name))
		return -EEXIST;
	name_alloc = kstrdup(name, GFP_KERNEL);
	if (!name_alloc) {
		ret = -ENOMEM;
		goto name_alloc_error;
	}
	event_field = kzalloc(sizeof(*event_field), GFP_KERNEL);
	if (!event_field) {
		ret = -ENOMEM;
		goto event_field_alloc_error;
	}
	event_field->name = name_alloc;
	event_field->type = field_type;

	events = lttng_kvzalloc(num_possible_cpus() * sizeof(*events), GFP_KERNEL);
	if (!events) {
		ret = -ENOMEM;
		goto event_alloc_error;
	}

	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;
	perf_field->name = name_alloc;
	perf_field->event_field = event_field;

	ctx_field.event_field = event_field;
	ctx_field.get_size = perf_counter_get_size;
	ctx_field.record = perf_counter_record;
	ctx_field.destroy = lttng_destroy_perf_counter_ctx_field;
	ctx_field.priv = perf_field;

#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
		get_online_cpus();
		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;
			}
		}
		put_online_cpus();
		perf_field->hp_enable = 1;
	}
#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */

	ret = lttng_kernel_context_append(ctx, &ctx_field);
	if (ret) {
		ret = -ENOMEM;
		goto append_context_error;
	}
	return 0;

	/* Error handling. */
append_context_error:
#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]);
		}
		put_online_cpus();
#ifdef CONFIG_HOTPLUG_CPU
		unregister_cpu_notifier(&perf_field->nb);
#endif
	}
#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
	kfree(perf_field);
error_alloc_perf_field:
	kfree(attr);
error_attr:
	lttng_kvfree(events);
event_alloc_error:
	kfree(event_field);
event_field_alloc_error:
	kfree(name_alloc);
name_alloc_error:
	return ret;
}
Commit	Line	Data
b7cdc182	1	/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
9f36eaed	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>
2df37e95	16	#include <lttng/events.h>
0fe45627	17	#include <lttng/events-internal.h>
24591303	18	#include <ringbuffer/frontend_types.h>
241ae9a8 MD	19	#include <wrapper/vmalloc.h>
241ae9a8 MD	20	#include <wrapper/perf.h>
2df37e95	21	#include <lttng/tracer.h>
833ad6a0	22
f1676205	23	static
a92e844e	24	size_t perf_counter_get_size(void priv, struct lttng_kernel_probe_ctx probe_ctx, size_t offset)
f1676205 MD	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	33	static
a92e844e	34	void perf_counter_record(void priv, struct lttng_kernel_probe_ctx probe_ctx,
8a57ec02	35	struct lttng_kernel_ring_buffer_ctx *ctx,
a90917c3	36	struct lttng_channel *chan)
833ad6a0	37	{
2dc781e0	38	struct lttng_perf_counter_field perf_field = (struct lttng_perf_counter_field ) priv;
833ad6a0 MD	39	struct perf_event *event;
	40	uint64_t value;
	41
b1199bd3	42	event = perf_field->e[ctx->priv.reserve_cpu];
0478c519	43	if (likely(event)) {
7b745a96 MD	44	if (unlikely(event->state == PERF_EVENT_STATE_ERROR)) {
	45	value = 0;
	46	} else {
	47	event->pmu->read(event);
	48	value = local64_read(&event->count);
	49	}
f91fd73b MD	50	} else {
	51	/*
	52	* Perf chooses not to be clever and not to support enabling a
	53	* perf counter before the cpu is brought up. Therefore, we need
	54	* to support having events coming (e.g. scheduler events)
	55	* before the counter is setup. Write an arbitrary 0 in this
	56	* case.
	57	*/
	58	value = 0;
	59	}
a90917c3	60	lib_ring_buffer_align_ctx(ctx, lttng_alignof(value));
833ad6a0 MD	61	chan->ops->event_write(ctx, &value, sizeof(value));
	62	}
	63
5f4c791e	64	#if defined(CONFIG_PERF_EVENTS) && (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,1,0))
90f5546c MD	65	static
	66	void overflow_callback(struct perf_event *event,
	67	struct perf_sample_data *data,
	68	struct pt_regs *regs)
	69	{
	70	}
	71	#else
833ad6a0 MD	72	static
	73	void overflow_callback(struct perf_event *event, int nmi,
	74	struct perf_sample_data *data,
	75	struct pt_regs *regs)
	76	{
	77	}
90f5546c	78	#endif
833ad6a0	79
2dccf128	80	static
2dc781e0	81	void lttng_destroy_perf_counter_ctx_field(void *priv)
2dccf128	82	{
2dc781e0	83	struct lttng_perf_counter_field *perf_field = priv;
437d5aa5	84	struct perf_event **events = perf_field->e;
2dccf128	85
5f4c791e	86	#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
1e367326 MD	87	{
	88	int ret;
	89
	90	ret = cpuhp_state_remove_instance(lttng_hp_online,
437d5aa5	91	&perf_field->cpuhp_online.node);
1e367326 MD	92	WARN_ON(ret);
1e367326 MD	93	ret = cpuhp_state_remove_instance(lttng_hp_prepare,
437d5aa5	94	&perf_field->cpuhp_prepare.node);
1e367326 MD	95	WARN_ON(ret);
1e367326 MD	96	}
5f4c791e	97	#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
1e367326 MD	98	{
	99	int cpu;
	100
	101	get_online_cpus();
	102	for_each_online_cpu(cpu)
	103	perf_event_release_kernel(events[cpu]);
	104	put_online_cpus();
8289661d	105	#ifdef CONFIG_HOTPLUG_CPU
437d5aa5	106	unregister_cpu_notifier(&perf_field->nb);
8289661d	107	#endif
1e367326	108	}
5f4c791e	109	#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
437d5aa5 MD	110	kfree(perf_field->name);
	111	kfree(perf_field->attr);
	112	kfree(perf_field->event_field);
48f5e0b5	113	lttng_kvfree(events);
437d5aa5	114	kfree(perf_field);
2dccf128 MD	115	}
2dccf128 MD	116
5f4c791e	117	#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
1e367326 MD	118
	119	int lttng_cpuhp_perf_counter_online(unsigned int cpu,
	120	struct lttng_cpuhp_node *node)
	121	{
	122	struct lttng_perf_counter_field *perf_field =
	123	container_of(node, struct lttng_perf_counter_field,
	124	cpuhp_online);
	125	struct perf_event **events = perf_field->e;
	126	struct perf_event_attr *attr = perf_field->attr;
	127	struct perf_event *pevent;
	128
	129	pevent = wrapper_perf_event_create_kernel_counter(attr,
	130	cpu, NULL, overflow_callback);
	131	if (!pevent \|\| IS_ERR(pevent))
	132	return -EINVAL;
	133	if (pevent->state == PERF_EVENT_STATE_ERROR) {
	134	perf_event_release_kernel(pevent);
	135	return -EINVAL;
	136	}
	137	barrier(); /* Create perf counter before setting event */
	138	events[cpu] = pevent;
	139	return 0;
	140	}
	141
	142	int lttng_cpuhp_perf_counter_dead(unsigned int cpu,
	143	struct lttng_cpuhp_node *node)
	144	{
	145	struct lttng_perf_counter_field *perf_field =
	146	container_of(node, struct lttng_perf_counter_field,
	147	cpuhp_prepare);
	148	struct perf_event **events = perf_field->e;
	149	struct perf_event *pevent;
	150
	151	pevent = events[cpu];
	152	events[cpu] = NULL;
	153	barrier(); /* NULLify event before perf counter teardown */
	154	perf_event_release_kernel(pevent);
	155	return 0;
	156	}
	157
5f4c791e	158	#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
1e367326	159
8289661d MD	160	#ifdef CONFIG_HOTPLUG_CPU
	161
	162	/**
	163	* lttng_perf_counter_hp_callback - CPU hotplug callback
	164	* @nb: notifier block
	165	* @action: hotplug action to take
	166	* @hcpu: CPU number
	167	*
	168	* Returns the success/failure of the operation. (%NOTIFY_OK, %NOTIFY_BAD)
	169	*
	170	* We can setup perf counters when the cpu is online (up prepare seems to be too
	171	* soon).
	172	*/
	173	static
e8f071d5	174	int lttng_perf_counter_cpu_hp_callback(struct notifier_block *nb,
8289661d MD	175	unsigned long action,
	176	void *hcpu)
	177	{
	178	unsigned int cpu = (unsigned long) hcpu;
2001023e MD	179	struct lttng_perf_counter_field *perf_field =
	180	container_of(nb, struct lttng_perf_counter_field, nb);
	181	struct perf_event **events = perf_field->e;
	182	struct perf_event_attr *attr = perf_field->attr;
f91fd73b	183	struct perf_event *pevent;
8289661d	184
2001023e	185	if (!perf_field->hp_enable)
8289661d MD	186	return NOTIFY_OK;
	187
	188	switch (action) {
	189	case CPU_ONLINE:
	190	case CPU_ONLINE_FROZEN:
90f5546c	191	pevent = wrapper_perf_event_create_kernel_counter(attr,
8289661d	192	cpu, NULL, overflow_callback);
0478c519	193	if (!pevent \|\| IS_ERR(pevent))
8289661d	194	return NOTIFY_BAD;
7b745a96 MD	195	if (pevent->state == PERF_EVENT_STATE_ERROR) {
	196	perf_event_release_kernel(pevent);
	197	return NOTIFY_BAD;
	198	}
f91fd73b MD	199	barrier(); /* Create perf counter before setting event */
f91fd73b MD	200	events[cpu] = pevent;
8289661d MD	201	break;
	202	case CPU_UP_CANCELED:
	203	case CPU_UP_CANCELED_FROZEN:
	204	case CPU_DEAD:
	205	case CPU_DEAD_FROZEN:
f91fd73b MD	206	pevent = events[cpu];
	207	events[cpu] = NULL;
	208	barrier(); /* NULLify event before perf counter teardown */
	209	perf_event_release_kernel(pevent);
8289661d MD	210	break;
	211	}
	212	return NOTIFY_OK;
	213	}
	214
	215	#endif
	216
5f4c791e	217	#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
1e367326	218
437d5aa5 MD	219	static const struct lttng_kernel_type_common *field_type =
	220	lttng_kernel_static_type_integer_from_type(uint64_t, __BYTE_ORDER, 10);
	221
833ad6a0 MD	222	int lttng_add_perf_counter_to_ctx(uint32_t type,
833ad6a0 MD	223	uint64_t config,
c24a0d71	224	const char *name,
437d5aa5	225	struct lttng_kernel_ctx **ctx)
833ad6a0	226	{
2836dd4f	227	struct lttng_kernel_ctx_field ctx_field = { 0 };
437d5aa5	228	struct lttng_kernel_event_field *event_field;
2001023e	229	struct lttng_perf_counter_field *perf_field;
833ad6a0 MD	230	struct perf_event **events;
	231	struct perf_event_attr *attr;
	232	int ret;
c24a0d71	233	char *name_alloc;
833ad6a0	234
437d5aa5 MD	235	if (lttng_kernel_find_context(*ctx, name))
	236	return -EEXIST;
	237	name_alloc = kstrdup(name, GFP_KERNEL);
	238	if (!name_alloc) {
	239	ret = -ENOMEM;
	240	goto name_alloc_error;
	241	}
	242	event_field = kzalloc(sizeof(*event_field), GFP_KERNEL);
	243	if (!event_field) {
	244	ret = -ENOMEM;
	245	goto event_field_alloc_error;
	246	}
	247	event_field->name = name_alloc;
	248	event_field->type = field_type;
	249
48f5e0b5	250	events = lttng_kvzalloc(num_possible_cpus() * sizeof(*events), GFP_KERNEL);
437d5aa5 MD	251	if (!events) {
	252	ret = -ENOMEM;
	253	goto event_alloc_error;
	254	}
833ad6a0	255
2001023e	256	attr = kzalloc(sizeof(struct perf_event_attr), GFP_KERNEL);
833ad6a0 MD	257	if (!attr) {
	258	ret = -ENOMEM;
	259	goto error_attr;
	260	}
	261
	262	attr->type = type;
	263	attr->config = config;
	264	attr->size = sizeof(struct perf_event_attr);
	265	attr->pinned = 1;
	266	attr->disabled = 0;
	267
2001023e MD	268	perf_field = kzalloc(sizeof(struct lttng_perf_counter_field), GFP_KERNEL);
	269	if (!perf_field) {
	270	ret = -ENOMEM;
	271	goto error_alloc_perf_field;
	272	}
	273	perf_field->e = events;
	274	perf_field->attr = attr;
437d5aa5 MD	275	perf_field->name = name_alloc;
437d5aa5 MD	276	perf_field->event_field = event_field;
2001023e	277
437d5aa5 MD	278	ctx_field.event_field = event_field;
	279	ctx_field.get_size = perf_counter_get_size;
	280	ctx_field.record = perf_counter_record;
	281	ctx_field.destroy = lttng_destroy_perf_counter_ctx_field;
	282	ctx_field.priv = perf_field;
8289661d	283
5f4c791e	284	#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
1e367326 MD	285
	286	perf_field->cpuhp_prepare.component = LTTNG_CONTEXT_PERF_COUNTERS;
	287	ret = cpuhp_state_add_instance(lttng_hp_prepare,
	288	&perf_field->cpuhp_prepare.node);
	289	if (ret)
	290	goto cpuhp_prepare_error;
	291
	292	perf_field->cpuhp_online.component = LTTNG_CONTEXT_PERF_COUNTERS;
	293	ret = cpuhp_state_add_instance(lttng_hp_online,
	294	&perf_field->cpuhp_online.node);
	295	if (ret)
	296	goto cpuhp_online_error;
	297
5f4c791e	298	#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
1e367326 MD	299	{
	300	int cpu;
	301
8289661d	302	#ifdef CONFIG_HOTPLUG_CPU
1e367326 MD	303	perf_field->nb.notifier_call =
	304	lttng_perf_counter_cpu_hp_callback;
	305	perf_field->nb.priority = 0;
	306	register_cpu_notifier(&perf_field->nb);
8289661d	307	#endif
1e367326 MD	308	get_online_cpus();
	309	for_each_online_cpu(cpu) {
	310	events[cpu] = wrapper_perf_event_create_kernel_counter(attr,
	311	cpu, NULL, overflow_callback);
	312	if (!events[cpu] \|\| IS_ERR(events[cpu])) {
	313	ret = -EINVAL;
	314	goto counter_error;
	315	}
	316	if (events[cpu]->state == PERF_EVENT_STATE_ERROR) {
	317	ret = -EBUSY;
	318	goto counter_busy;
	319	}
7b745a96	320	}
1e367326 MD	321	put_online_cpus();
1e367326 MD	322	perf_field->hp_enable = 1;
8289661d	323	}
5f4c791e	324	#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
8289661d	325
437d5aa5 MD	326	ret = lttng_kernel_context_append(ctx, &ctx_field);
	327	if (ret) {
	328	ret = -ENOMEM;
	329	goto append_context_error;
	330	}
833ad6a0 MD	331	return 0;
833ad6a0 MD	332
437d5aa5 MD	333	/* Error handling. */
437d5aa5 MD	334	append_context_error:
5f4c791e	335	#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0))
1e367326 MD	336	cpuhp_online_error:
	337	{
	338	int remove_ret;
	339
	340	remove_ret = cpuhp_state_remove_instance(lttng_hp_prepare,
	341	&perf_field->cpuhp_prepare.node);
	342	WARN_ON(remove_ret);
	343	}
	344	cpuhp_prepare_error:
5f4c791e	345	#else /* #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
7b745a96	346	counter_busy:
8289661d	347	counter_error:
ce4a2f0c MD	348	{
	349	int cpu;
	350
	351	for_each_online_cpu(cpu) {
	352	if (events[cpu] && !IS_ERR(events[cpu]))
	353	perf_event_release_kernel(events[cpu]);
	354	}
	355	put_online_cpus();
8289661d	356	#ifdef CONFIG_HOTPLUG_CPU
ce4a2f0c	357	unregister_cpu_notifier(&perf_field->nb);
8289661d	358	#endif
ce4a2f0c	359	}
5f4c791e	360	#endif /* #else #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,10,0)) */
2001023e MD	361	kfree(perf_field);
2001023e MD	362	error_alloc_perf_field:
833ad6a0 MD	363	kfree(attr);
833ad6a0 MD	364	error_attr:
48f5e0b5	365	lttng_kvfree(events);
437d5aa5 MD	366	event_alloc_error:
	367	kfree(event_field);
	368	event_field_alloc_error:
	369	kfree(name_alloc);
	370	name_alloc_error:
833ad6a0 MD	371	return ret;
833ad6a0 MD	372	}