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

/*
 * (C) Copyright	2009-2011 -
 * 		Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * LTTng priority context.
 *
 * Dual LGPL v2.1/GPL v2 license.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include "ltt-events.h"
#include "wrapper/ringbuffer/frontend_types.h"
#include "wrapper/vmalloc.h"
#include "wrapper/kallsyms.h"
#include "ltt-tracer.h"

static
int (*wrapper_task_prio_sym)(struct task_struct *t);

int wrapper_task_prio_init(void)
{
	wrapper_task_prio_sym = (void *) kallsyms_lookup_funcptr("task_prio");
	if (!wrapper_task_prio_sym) {
		printk(KERN_WARNING "LTTng: task_prio symbol lookup failed.\n");
		return -EINVAL;
	}
	return 0;
}

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

	size += lib_ring_buffer_align(offset, ltt_alignof(int));
	size += sizeof(int);
	return size;
}

static
void prio_record(struct lttng_ctx_field *field,
		struct lib_ring_buffer_ctx *ctx,
		struct ltt_channel *chan)
{
	int prio;

	prio = wrapper_task_prio_sym(current);
	lib_ring_buffer_align_ctx(ctx, ltt_alignof(prio));
	chan->ops->event_write(ctx, &prio, sizeof(prio));
}

int lttng_add_prio_to_ctx(struct lttng_ctx **ctx)
{
	struct lttng_ctx_field *field;
	int ret;

	if (!wrapper_task_prio_sym) {
		ret = wrapper_task_prio_init();
		if (ret)
			return ret;
	}

	field = lttng_append_context(ctx);
	if (!field)
		return -ENOMEM;
	if (lttng_find_context(*ctx, "prio")) {
		lttng_remove_context_field(ctx, field);
		return -EEXIST;
	}
	field->event_field.name = "prio";
	field->event_field.type.atype = atype_integer;
	field->event_field.type.u.basic.integer.size = sizeof(int) * CHAR_BIT;
	field->event_field.type.u.basic.integer.alignment = ltt_alignof(int) * CHAR_BIT;
	field->event_field.type.u.basic.integer.signedness = is_signed_type(int);
	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 = prio_get_size;
	field->record = prio_record;
	wrapper_vmalloc_sync_all();
	return 0;
}
EXPORT_SYMBOL_GPL(lttng_add_prio_to_ctx);

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Linux Trace Toolkit Priority Context");
Commit	Line	Data
a8ad3613 MD	1	/*
	2	* (C) Copyright 2009-2011 -
	3	* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	*
	5	* LTTng priority context.
	6	*
	7	* Dual LGPL v2.1/GPL v2 license.
	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/slab.h>
	12	#include <linux/sched.h>
	13	#include "ltt-events.h"
	14	#include "wrapper/ringbuffer/frontend_types.h"
	15	#include "wrapper/vmalloc.h"
c539a324	16	#include "wrapper/kallsyms.h"
a8ad3613 MD	17	#include "ltt-tracer.h"
a8ad3613 MD	18
979133c5 MD	19	static
	20	int (wrapper_task_prio_sym)(struct task_struct t);
	21
	22	int wrapper_task_prio_init(void)
	23	{
c539a324	24	wrapper_task_prio_sym = (void *) kallsyms_lookup_funcptr("task_prio");
979133c5 MD	25	if (!wrapper_task_prio_sym) {
	26	printk(KERN_WARNING "LTTng: task_prio symbol lookup failed.\n");
	27	return -EINVAL;
	28	}
	29	return 0;
	30	}
	31
a8ad3613 MD	32	static
	33	size_t prio_get_size(size_t offset)
	34	{
	35	size_t size = 0;
	36
	37	size += lib_ring_buffer_align(offset, ltt_alignof(int));
	38	size += sizeof(int);
	39	return size;
	40	}
	41
	42	static
	43	void prio_record(struct lttng_ctx_field *field,
	44	struct lib_ring_buffer_ctx *ctx,
	45	struct ltt_channel *chan)
	46	{
	47	int prio;
	48
8fefc8a2	49	prio = wrapper_task_prio_sym(current);
53f1f0ca MD	50	lib_ring_buffer_align_ctx(ctx, ltt_alignof(prio));
53f1f0ca MD	51	chan->ops->event_write(ctx, &prio, sizeof(prio));
a8ad3613 MD	52	}
	53
	54	int lttng_add_prio_to_ctx(struct lttng_ctx **ctx)
	55	{
	56	struct lttng_ctx_field *field;
	57	int ret;
	58
979133c5 MD	59	if (!wrapper_task_prio_sym) {
	60	ret = wrapper_task_prio_init();
	61	if (ret)
	62	return ret;
	63	}
	64
a8ad3613 MD	65	field = lttng_append_context(ctx);
a8ad3613 MD	66	if (!field)
09fec6b4	67	return -ENOMEM;
44252f0f MD	68	if (lttng_find_context(*ctx, "prio")) {
	69	lttng_remove_context_field(ctx, field);
	70	return -EEXIST;
	71	}
a8ad3613 MD	72	field->event_field.name = "prio";
	73	field->event_field.type.atype = atype_integer;
	74	field->event_field.type.u.basic.integer.size = sizeof(int) * CHAR_BIT;
	75	field->event_field.type.u.basic.integer.alignment = ltt_alignof(int) * CHAR_BIT;
	76	field->event_field.type.u.basic.integer.signedness = is_signed_type(int);
	77	field->event_field.type.u.basic.integer.reverse_byte_order = 0;
	78	field->event_field.type.u.basic.integer.base = 10;
	79	field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
	80	field->get_size = prio_get_size;
	81	field->record = prio_record;
	82	wrapper_vmalloc_sync_all();
	83	return 0;
	84	}
	85	EXPORT_SYMBOL_GPL(lttng_add_prio_to_ctx);
	86
	87	MODULE_LICENSE("GPL and additional rights");
	88	MODULE_AUTHOR("Mathieu Desnoyers");
53f1f0ca	89	MODULE_DESCRIPTION("Linux Trace Toolkit Priority Context");