[lttng-modules.git] / src / lttng-context-prio.c

/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
 *
 * lttng-context-prio.c
 *
 * LTTng priority context.
 *
 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <lttng/events.h>
#include <lttng/events-internal.h>
#include <ringbuffer/frontend_types.h>
#include <wrapper/vmalloc.h>
#include <lttng/tracer.h>
#include <lttng/kernel-version.h>

/*
 * From kernel v3.0 to v3.8, MAX_RT_PRIO is defined in linux/sched.h.
 * From kernel v3.9 to v3.14, MAX_RT_PRIO is defined in linux/sched/rt.h,
 * which is not included by linux/sched.h (hence this work-around).
 * From kernel v3.15 onwards, MAX_RT_PRIO is defined in linux/sched/prio.h,
 * which is included by linux/sched.h.
 */
#if LTTNG_KERNEL_RANGE(3,9,0, 3,15,0)
# include <linux/sched/rt.h>
#endif

/*
 * task_prio() has been implemented as p->prio - MAX_RT_PRIO since at
 * least kernel v3.0.
 */
static
int wrapper_task_prio(struct task_struct *p)
{
	return p->prio - MAX_RT_PRIO;
}

static
size_t prio_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(int));
	size += sizeof(int);
	return size;
}

static
void prio_record(void *priv, struct lttng_kernel_probe_ctx *probe_ctx,
		struct lttng_kernel_ring_buffer_ctx *ctx,
		struct lttng_kernel_channel_buffer *chan)
{
	int prio;

	prio = wrapper_task_prio(current);
	chan->ops->event_write(ctx, &prio, sizeof(prio), lttng_alignof(prio));
}

static
void prio_get_value(void *priv,
		struct lttng_kernel_probe_ctx *lttng_probe_ctx,
		struct lttng_ctx_value *value)
{
	value->u.s64 = wrapper_task_prio(current);
}

static const struct lttng_kernel_ctx_field *ctx_field = lttng_kernel_static_ctx_field(
	lttng_kernel_static_event_field("prio",
		lttng_kernel_static_type_integer_from_type(int, __BYTE_ORDER, 10),
		false, false),
	prio_get_size,
	prio_record,
	prio_get_value,
	NULL, NULL);

int lttng_add_prio_to_ctx(struct lttng_kernel_ctx **ctx)
{
	int ret;

	if (lttng_kernel_find_context(*ctx, ctx_field->event_field->name))
		return -EEXIST;
	ret = lttng_kernel_context_append(ctx, ctx_field);
	wrapper_vmalloc_sync_mappings();
	return ret;
}
EXPORT_SYMBOL_GPL(lttng_add_prio_to_ctx);
Commit	Line	Data
b7cdc182	1	/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
9f36eaed	2	*
886d51a3	3	* lttng-context-prio.c
a8ad3613 MD	4	*
	5	* LTTng priority context.
	6	*
886d51a3	7	* Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
a8ad3613 MD	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/slab.h>
	12	#include <linux/sched.h>
2df37e95	13	#include <lttng/events.h>
437d5aa5	14	#include <lttng/events-internal.h>
24591303	15	#include <ringbuffer/frontend_types.h>
241ae9a8	16	#include <wrapper/vmalloc.h>
2df37e95	17	#include <lttng/tracer.h>
c63b1067 MD	18	#include <lttng/kernel-version.h>
	19
	20	/*
	21	* From kernel v3.0 to v3.8, MAX_RT_PRIO is defined in linux/sched.h.
	22	* From kernel v3.9 to v3.14, MAX_RT_PRIO is defined in linux/sched/rt.h,
	23	* which is not included by linux/sched.h (hence this work-around).
	24	* From kernel v3.15 onwards, MAX_RT_PRIO is defined in linux/sched/prio.h,
	25	* which is included by linux/sched.h.
	26	*/
	27	#if LTTNG_KERNEL_RANGE(3,9,0, 3,15,0)
	28	# include <linux/sched/rt.h>
	29	#endif
a8ad3613	30
3dfec228	31	/*
7f1fa632 MD	32	* task_prio() has been implemented as p->prio - MAX_RT_PRIO since at
7f1fa632 MD	33	* least kernel v3.0.
3dfec228	34	*/
7f1fa632 MD	35	static
7f1fa632 MD	36	int wrapper_task_prio(struct task_struct *p)
3dfec228	37	{
7f1fa632	38	return p->prio - MAX_RT_PRIO;
3dfec228 MJ	39	}
3dfec228 MJ	40
a8ad3613	41	static
346cb5ee	42	size_t prio_get_size(void priv, struct lttng_kernel_probe_ctx probe_ctx, size_t offset)
a8ad3613 MD	43	{
	44	size_t size = 0;
	45
a90917c3	46	size += lib_ring_buffer_align(offset, lttng_alignof(int));
a8ad3613 MD	47	size += sizeof(int);
	48	return size;
	49	}
	50
	51	static
346cb5ee	52	void prio_record(void priv, struct lttng_kernel_probe_ctx probe_ctx,
e27e4381	53	struct lttng_kernel_ring_buffer_ctx *ctx,
ac847066	54	struct lttng_kernel_channel_buffer *chan)
a8ad3613 MD	55	{
	56	int prio;
	57
7f1fa632	58	prio = wrapper_task_prio(current);
77fcffef	59	chan->ops->event_write(ctx, &prio, sizeof(prio), lttng_alignof(prio));
a8ad3613 MD	60	}
a8ad3613 MD	61
f127e61e	62	static
ea2d95e4	63	void prio_get_value(void *priv,
346cb5ee	64	struct lttng_kernel_probe_ctx *lttng_probe_ctx,
ea2d95e4	65	struct lttng_ctx_value *value)
f127e61e	66	{
7f1fa632	67	value->u.s64 = wrapper_task_prio(current);
f127e61e MD	68	}
f127e61e MD	69
437d5aa5 MD	70	static const struct lttng_kernel_ctx_field *ctx_field = lttng_kernel_static_ctx_field(
	71	lttng_kernel_static_event_field("prio",
	72	lttng_kernel_static_type_integer_from_type(int, __BYTE_ORDER, 10),
07aafa15	73	false, false),
437d5aa5	74	prio_get_size,
437d5aa5 MD	75	prio_record,
	76	prio_get_value,
	77	NULL, NULL);
	78
	79	int lttng_add_prio_to_ctx(struct lttng_kernel_ctx **ctx)
a8ad3613	80	{
a8ad3613 MD	81	int ret;
a8ad3613 MD	82
437d5aa5	83	if (lttng_kernel_find_context(*ctx, ctx_field->event_field->name))
44252f0f	84	return -EEXIST;
437d5aa5	85	ret = lttng_kernel_context_append(ctx, ctx_field);
263b6c88	86	wrapper_vmalloc_sync_mappings();
437d5aa5	87	return ret;
a8ad3613 MD	88	}
a8ad3613 MD	89	EXPORT_SYMBOL_GPL(lttng_add_prio_to_ctx);