2 * ltt-ring-buffer-client.h
4 * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6 * LTTng lib ring buffer client template.
8 * Dual LGPL v2.1/GPL v2 license.
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */
14 #include "ltt-events.h"
15 #include "ltt-tracer.h"
17 struct metadata_packet_header
{
18 uint32_t magic
; /* 0x75D11D57 */
19 uint8_t uuid
[16]; /* Unique Universal Identifier */
20 uint32_t checksum
; /* 0 if unused */
21 uint32_t content_size
; /* in bits */
22 uint32_t packet_size
; /* in bits */
23 uint8_t compression_scheme
; /* 0 if unused */
24 uint8_t encryption_scheme
; /* 0 if unused */
25 uint8_t checksum_scheme
; /* 0 if unused */
26 uint8_t header_end
[0];
29 struct metadata_record_header
{
30 uint8_t header_end
[0]; /* End of header */
33 static const struct lib_ring_buffer_config client_config
;
36 u64
lib_ring_buffer_clock_read(struct channel
*chan
)
42 unsigned char record_header_size(const struct lib_ring_buffer_config
*config
,
43 struct channel
*chan
, size_t offset
,
44 size_t *pre_header_padding
,
45 struct lib_ring_buffer_ctx
*ctx
)
50 #include "wrapper/ringbuffer/api.h"
52 static u64
client_ring_buffer_clock_read(struct channel
*chan
)
58 size_t client_record_header_size(const struct lib_ring_buffer_config
*config
,
59 struct channel
*chan
, size_t offset
,
60 size_t *pre_header_padding
,
61 struct lib_ring_buffer_ctx
*ctx
)
67 * client_packet_header_size - called on buffer-switch to a new sub-buffer
69 * Return header size without padding after the structure. Don't use packed
70 * structure because gcc generates inefficient code on some architectures
73 static size_t client_packet_header_size(void)
75 return offsetof(struct metadata_packet_header
, header_end
);
78 static void client_buffer_begin(struct lib_ring_buffer
*buf
, u64 tsc
,
79 unsigned int subbuf_idx
)
81 struct channel
*chan
= buf
->backend
.chan
;
82 struct metadata_packet_header
*header
=
83 (struct metadata_packet_header
*)
84 lib_ring_buffer_offset_address(&buf
->backend
,
85 subbuf_idx
* chan
->backend
.subbuf_size
);
86 struct ltt_channel
*ltt_chan
= channel_get_private(chan
);
87 struct ltt_session
*session
= ltt_chan
->session
;
89 header
->magic
= TSDL_MAGIC_NUMBER
;
90 memcpy(header
->uuid
, session
->uuid
.b
, sizeof(session
->uuid
));
91 header
->checksum
= 0; /* 0 if unused */
92 header
->content_size
= 0xFFFFFFFF; /* in bits, for debugging */
93 header
->packet_size
= 0xFFFFFFFF; /* in bits, for debugging */
94 header
->compression_scheme
= 0; /* 0 if unused */
95 header
->encryption_scheme
= 0; /* 0 if unused */
96 header
->checksum_scheme
= 0; /* 0 if unused */
100 * offset is assumed to never be 0 here : never deliver a completely empty
101 * subbuffer. data_size is between 1 and subbuf_size.
103 static void client_buffer_end(struct lib_ring_buffer
*buf
, u64 tsc
,
104 unsigned int subbuf_idx
, unsigned long data_size
)
106 struct channel
*chan
= buf
->backend
.chan
;
107 struct metadata_packet_header
*header
=
108 (struct metadata_packet_header
*)
109 lib_ring_buffer_offset_address(&buf
->backend
,
110 subbuf_idx
* chan
->backend
.subbuf_size
);
111 unsigned long records_lost
= 0;
113 header
->content_size
= data_size
* CHAR_BIT
; /* in bits */
114 header
->packet_size
= PAGE_ALIGN(data_size
) * CHAR_BIT
; /* in bits */
115 records_lost
+= lib_ring_buffer_get_records_lost_full(&client_config
, buf
);
116 records_lost
+= lib_ring_buffer_get_records_lost_wrap(&client_config
, buf
);
117 records_lost
+= lib_ring_buffer_get_records_lost_big(&client_config
, buf
);
118 WARN_ON_ONCE(records_lost
!= 0);
121 static int client_buffer_create(struct lib_ring_buffer
*buf
, void *priv
,
122 int cpu
, const char *name
)
127 static void client_buffer_finalize(struct lib_ring_buffer
*buf
, void *priv
, int cpu
)
131 static const struct lib_ring_buffer_config client_config
= {
132 .cb
.ring_buffer_clock_read
= client_ring_buffer_clock_read
,
133 .cb
.record_header_size
= client_record_header_size
,
134 .cb
.subbuffer_header_size
= client_packet_header_size
,
135 .cb
.buffer_begin
= client_buffer_begin
,
136 .cb
.buffer_end
= client_buffer_end
,
137 .cb
.buffer_create
= client_buffer_create
,
138 .cb
.buffer_finalize
= client_buffer_finalize
,
141 .alloc
= RING_BUFFER_ALLOC_GLOBAL
,
142 .sync
= RING_BUFFER_SYNC_GLOBAL
,
143 .mode
= RING_BUFFER_MODE_TEMPLATE
,
144 .backend
= RING_BUFFER_PAGE
,
145 .output
= RING_BUFFER_OUTPUT_TEMPLATE
,
146 .oops
= RING_BUFFER_OOPS_CONSISTENCY
,
147 .ipi
= RING_BUFFER_IPI_BARRIER
,
148 .wakeup
= RING_BUFFER_WAKEUP_BY_TIMER
,
152 struct channel
*_channel_create(const char *name
,
153 struct ltt_channel
*ltt_chan
, void *buf_addr
,
154 size_t subbuf_size
, size_t num_subbuf
,
155 unsigned int switch_timer_interval
,
156 unsigned int read_timer_interval
)
158 return channel_create(&client_config
, name
, ltt_chan
, buf_addr
,
159 subbuf_size
, num_subbuf
, switch_timer_interval
,
160 read_timer_interval
);
164 void ltt_channel_destroy(struct channel
*chan
)
166 channel_destroy(chan
);
170 struct lib_ring_buffer
*ltt_buffer_read_open(struct channel
*chan
)
172 struct lib_ring_buffer
*buf
;
174 buf
= channel_get_ring_buffer(&client_config
, chan
, 0);
175 if (!lib_ring_buffer_open_read(buf
))
181 int ltt_buffer_has_read_closed_stream(struct channel
*chan
)
183 struct lib_ring_buffer
*buf
;
186 for_each_channel_cpu(cpu
, chan
) {
187 buf
= channel_get_ring_buffer(&client_config
, chan
, cpu
);
188 if (!atomic_long_read(&buf
->active_readers
))
195 void ltt_buffer_read_close(struct lib_ring_buffer
*buf
)
197 lib_ring_buffer_release_read(buf
);
201 int ltt_event_reserve(struct lib_ring_buffer_ctx
*ctx
, uint32_t event_id
)
203 return lib_ring_buffer_reserve(&client_config
, ctx
);
207 void ltt_event_commit(struct lib_ring_buffer_ctx
*ctx
)
209 lib_ring_buffer_commit(&client_config
, ctx
);
213 void ltt_event_write(struct lib_ring_buffer_ctx
*ctx
, const void *src
,
216 lib_ring_buffer_write(&client_config
, ctx
, src
, len
);
220 size_t ltt_packet_avail_size(struct channel
*chan
)
223 unsigned long o_begin
;
224 struct lib_ring_buffer
*buf
;
226 buf
= chan
->backend
.buf
; /* Only for global buffer ! */
227 o_begin
= v_read(&client_config
, &buf
->offset
);
228 if (subbuf_offset(o_begin
, chan
) != 0) {
229 return chan
->backend
.subbuf_size
- subbuf_offset(o_begin
, chan
);
231 return chan
->backend
.subbuf_size
- subbuf_offset(o_begin
, chan
)
232 - sizeof(struct metadata_packet_header
);
237 wait_queue_head_t
*ltt_get_reader_wait_queue(struct channel
*chan
)
239 return &chan
->read_wait
;
243 wait_queue_head_t
*ltt_get_hp_wait_queue(struct channel
*chan
)
245 return &chan
->hp_wait
;
249 int ltt_is_finalized(struct channel
*chan
)
251 return lib_ring_buffer_channel_is_finalized(chan
);
255 int ltt_is_disabled(struct channel
*chan
)
257 return lib_ring_buffer_channel_is_disabled(chan
);
260 static struct ltt_transport ltt_relay_transport
= {
261 .name
= "relay-" RING_BUFFER_MODE_TEMPLATE_STRING
,
262 .owner
= THIS_MODULE
,
264 .channel_create
= _channel_create
,
265 .channel_destroy
= ltt_channel_destroy
,
266 .buffer_read_open
= ltt_buffer_read_open
,
267 .buffer_has_read_closed_stream
=
268 ltt_buffer_has_read_closed_stream
,
269 .buffer_read_close
= ltt_buffer_read_close
,
270 .event_reserve
= ltt_event_reserve
,
271 .event_commit
= ltt_event_commit
,
272 .event_write
= ltt_event_write
,
273 .packet_avail_size
= ltt_packet_avail_size
,
274 .get_reader_wait_queue
= ltt_get_reader_wait_queue
,
275 .get_hp_wait_queue
= ltt_get_hp_wait_queue
,
276 .is_finalized
= ltt_is_finalized
,
277 .is_disabled
= ltt_is_disabled
,
281 static int __init
ltt_ring_buffer_client_init(void)
284 * This vmalloc sync all also takes care of the lib ring buffer
285 * vmalloc'd module pages when it is built as a module into LTTng.
287 wrapper_vmalloc_sync_all();
288 ltt_transport_register(<t_relay_transport
);
292 module_init(ltt_ring_buffer_client_init
);
294 static void __exit
ltt_ring_buffer_client_exit(void)
296 ltt_transport_unregister(<t_relay_transport
);
299 module_exit(ltt_ring_buffer_client_exit
);
301 MODULE_LICENSE("GPL and additional rights");
302 MODULE_AUTHOR("Mathieu Desnoyers");
303 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING