Fix: flush empty packets on snapshot channel
[lttng-modules.git] / lttng-context-tid.c
CommitLineData
b64bc438 1/*
886d51a3 2 * lttng-context-tid.c
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3 *
4 * LTTng TID context.
5 *
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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
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21 */
22
23#include <linux/module.h>
24#include <linux/slab.h>
25#include <linux/sched.h>
a90917c3 26#include "lttng-events.h"
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27#include "wrapper/ringbuffer/frontend_types.h"
28#include "wrapper/vmalloc.h"
a90917c3 29#include "lttng-tracer.h"
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30
31static
32size_t tid_get_size(size_t offset)
33{
34 size_t size = 0;
35
a90917c3 36 size += lib_ring_buffer_align(offset, lttng_alignof(pid_t));
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37 size += sizeof(pid_t);
38 return size;
39}
40
41static
42void tid_record(struct lttng_ctx_field *field,
43 struct lib_ring_buffer_ctx *ctx,
a90917c3 44 struct lttng_channel *chan)
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45{
46 pid_t tid;
47
48 tid = task_pid_nr(current);
a90917c3 49 lib_ring_buffer_align_ctx(ctx, lttng_alignof(tid));
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50 chan->ops->event_write(ctx, &tid, sizeof(tid));
51}
52
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53static
54void tid_get_value(struct lttng_ctx_field *field,
55 union lttng_ctx_value *value)
56{
57 pid_t tid;
58
59 tid = task_pid_nr(current);
60 value->s64 = tid;
61}
62
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63int lttng_add_tid_to_ctx(struct lttng_ctx **ctx)
64{
65 struct lttng_ctx_field *field;
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66
67 field = lttng_append_context(ctx);
68 if (!field)
09fec6b4 69 return -ENOMEM;
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70 if (lttng_find_context(*ctx, "tid")) {
71 lttng_remove_context_field(ctx, field);
72 return -EEXIST;
73 }
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74 field->event_field.name = "tid";
75 field->event_field.type.atype = atype_integer;
76 field->event_field.type.u.basic.integer.size = sizeof(pid_t) * CHAR_BIT;
a90917c3 77 field->event_field.type.u.basic.integer.alignment = lttng_alignof(pid_t) * CHAR_BIT;
06254b0f 78 field->event_field.type.u.basic.integer.signedness = lttng_is_signed_type(pid_t);
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79 field->event_field.type.u.basic.integer.reverse_byte_order = 0;
80 field->event_field.type.u.basic.integer.base = 10;
81 field->event_field.type.u.basic.integer.encoding = lttng_encode_none;
82 field->get_size = tid_get_size;
83 field->record = tid_record;
f127e61e 84 field->get_value = tid_get_value;
a9dd15da 85 lttng_context_update(*ctx);
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86 wrapper_vmalloc_sync_all();
87 return 0;
88}
89EXPORT_SYMBOL_GPL(lttng_add_tid_to_ctx);
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