Version 2.7.7
[lttng-modules.git] / lttng-context-cpu-id.c
CommitLineData
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1/*
2 * lttng-context-cpu-id.c
3 *
4 * LTTng CPU id context.
5 *
6 * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; only
11 * version 2.1 of the License.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include <linux/module.h>
24#include <linux/slab.h>
25#include <linux/sched.h>
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26#include "lttng-events.h"
27#include "wrapper/ringbuffer/frontend_types.h"
28#include "wrapper/vmalloc.h"
29#include "lttng-tracer.h"
30
31static
32size_t cpu_id_get_size(size_t offset)
33{
34 size_t size = 0;
35
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36 size += lib_ring_buffer_align(offset, lttng_alignof(int));
37 size += sizeof(int);
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38 return size;
39}
40
41static
42void cpu_id_record(struct lttng_ctx_field *field,
43 struct lib_ring_buffer_ctx *ctx,
44 struct lttng_channel *chan)
45{
1c23b886 46 int cpu;
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47
48 cpu = ctx->cpu;
49 lib_ring_buffer_align_ctx(ctx, lttng_alignof(cpu));
50 chan->ops->event_write(ctx, &cpu, sizeof(cpu));
51}
52
53static
54void cpu_id_get_value(struct lttng_ctx_field *field,
55 union lttng_ctx_value *value)
56{
57 value->s64 = smp_processor_id();
58}
59
60int lttng_add_cpu_id_to_ctx(struct lttng_ctx **ctx)
61{
62 struct lttng_ctx_field *field;
63
64 field = lttng_append_context(ctx);
65 if (!field)
66 return -ENOMEM;
67 if (lttng_find_context(*ctx, "cpu_id")) {
68 lttng_remove_context_field(ctx, field);
69 return -EEXIST;
70 }
71 field->event_field.name = "cpu_id";
72 field->event_field.type.atype = atype_integer;
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73 field->event_field.type.u.basic.integer.size = sizeof(int) * CHAR_BIT;
74 field->event_field.type.u.basic.integer.alignment = lttng_alignof(int) * CHAR_BIT;
75 field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(int);
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76 field->event_field.type.u.basic.integer.reverse_byte_order = 0;
77 field->event_field.type.u.basic.integer.base = 10;
78 field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
79 field->get_size = cpu_id_get_size;
80 field->record = cpu_id_record;
81 field->get_value = cpu_id_get_value;
82 lttng_context_update(*ctx);
83 wrapper_vmalloc_sync_all();
84 return 0;
85}
86EXPORT_SYMBOL_GPL(lttng_add_cpu_id_to_ctx);
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