1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
3 * lttng-ring-buffer-client.h
5 * LTTng lib ring buffer client template.
7 * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 #include <linux/module.h>
11 #include <linux/types.h>
12 #include <wrapper/vmalloc.h> /* for wrapper_vmalloc_sync_mappings() */
13 #include <lttng/events.h>
14 #include <lttng/tracer.h>
16 static struct lttng_transport lttng_relay_transport
;
18 struct metadata_packet_header
{
19 uint32_t magic
; /* 0x75D11D57 */
20 uint8_t uuid
[16]; /* Unique Universal Identifier */
21 uint32_t checksum
; /* 0 if unused */
22 uint32_t content_size
; /* in bits */
23 uint32_t packet_size
; /* in bits */
24 uint8_t compression_scheme
; /* 0 if unused */
25 uint8_t encryption_scheme
; /* 0 if unused */
26 uint8_t checksum_scheme
; /* 0 if unused */
27 uint8_t major
; /* CTF spec major version number */
28 uint8_t minor
; /* CTF spec minor version number */
29 uint8_t header_end
[0];
32 struct metadata_record_header
{
33 uint8_t header_end
[0]; /* End of header */
36 static const struct lib_ring_buffer_config client_config
;
39 u64
lib_ring_buffer_clock_read(struct channel
*chan
)
45 size_t record_header_size(const struct lib_ring_buffer_config
*config
,
46 struct channel
*chan
, size_t offset
,
47 size_t *pre_header_padding
,
48 struct lib_ring_buffer_ctx
*ctx
,
54 #include <ringbuffer/api.h>
56 static u64
client_ring_buffer_clock_read(struct channel
*chan
)
62 size_t client_record_header_size(const struct lib_ring_buffer_config
*config
,
63 struct channel
*chan
, size_t offset
,
64 size_t *pre_header_padding
,
65 struct lib_ring_buffer_ctx
*ctx
,
72 * client_packet_header_size - called on buffer-switch to a new sub-buffer
74 * Return header size without padding after the structure. Don't use packed
75 * structure because gcc generates inefficient code on some architectures
78 static size_t client_packet_header_size(void)
80 return offsetof(struct metadata_packet_header
, header_end
);
83 static void client_buffer_begin(struct lib_ring_buffer
*buf
, u64 tsc
,
84 unsigned int subbuf_idx
)
86 struct channel
*chan
= buf
->backend
.chan
;
87 struct metadata_packet_header
*header
=
88 (struct metadata_packet_header
*)
89 lib_ring_buffer_offset_address(&buf
->backend
,
90 subbuf_idx
* chan
->backend
.subbuf_size
);
91 struct lttng_metadata_cache
*metadata_cache
=
92 channel_get_private(chan
);
94 header
->magic
= TSDL_MAGIC_NUMBER
;
95 memcpy(header
->uuid
, metadata_cache
->uuid
.b
,
96 sizeof(metadata_cache
->uuid
));
97 header
->checksum
= 0; /* 0 if unused */
98 header
->content_size
= 0xFFFFFFFF; /* in bits, for debugging */
99 header
->packet_size
= 0xFFFFFFFF; /* in bits, for debugging */
100 header
->compression_scheme
= 0; /* 0 if unused */
101 header
->encryption_scheme
= 0; /* 0 if unused */
102 header
->checksum_scheme
= 0; /* 0 if unused */
103 header
->major
= CTF_SPEC_MAJOR
;
104 header
->minor
= CTF_SPEC_MINOR
;
108 * offset is assumed to never be 0 here : never deliver a completely empty
109 * subbuffer. data_size is between 1 and subbuf_size.
111 static void client_buffer_end(struct lib_ring_buffer
*buf
, u64 tsc
,
112 unsigned int subbuf_idx
, unsigned long data_size
)
114 struct channel
*chan
= buf
->backend
.chan
;
115 struct metadata_packet_header
*header
=
116 (struct metadata_packet_header
*)
117 lib_ring_buffer_offset_address(&buf
->backend
,
118 subbuf_idx
* chan
->backend
.subbuf_size
);
119 unsigned long records_lost
= 0;
121 header
->content_size
= data_size
* CHAR_BIT
; /* in bits */
122 header
->packet_size
= PAGE_ALIGN(data_size
) * CHAR_BIT
; /* in bits */
124 * We do not care about the records lost count, because the metadata
125 * channel waits and retry.
127 (void) lib_ring_buffer_get_records_lost_full(&client_config
, buf
);
128 records_lost
+= lib_ring_buffer_get_records_lost_wrap(&client_config
, buf
);
129 records_lost
+= lib_ring_buffer_get_records_lost_big(&client_config
, buf
);
130 WARN_ON_ONCE(records_lost
!= 0);
133 static int client_buffer_create(struct lib_ring_buffer
*buf
, void *priv
,
134 int cpu
, const char *name
)
139 static void client_buffer_finalize(struct lib_ring_buffer
*buf
, void *priv
, int cpu
)
143 static int client_timestamp_begin(const struct lib_ring_buffer_config
*config
,
144 struct lib_ring_buffer
*buf
, uint64_t *timestamp_begin
)
149 static int client_timestamp_end(const struct lib_ring_buffer_config
*config
,
150 struct lib_ring_buffer
*bufb
,
151 uint64_t *timestamp_end
)
156 static int client_events_discarded(const struct lib_ring_buffer_config
*config
,
157 struct lib_ring_buffer
*bufb
,
158 uint64_t *events_discarded
)
163 static int client_current_timestamp(const struct lib_ring_buffer_config
*config
,
164 struct lib_ring_buffer
*bufb
,
170 static int client_content_size(const struct lib_ring_buffer_config
*config
,
171 struct lib_ring_buffer
*bufb
,
172 uint64_t *content_size
)
177 static int client_packet_size(const struct lib_ring_buffer_config
*config
,
178 struct lib_ring_buffer
*bufb
,
179 uint64_t *packet_size
)
184 static int client_stream_id(const struct lib_ring_buffer_config
*config
,
185 struct lib_ring_buffer
*bufb
,
191 static int client_sequence_number(const struct lib_ring_buffer_config
*config
,
192 struct lib_ring_buffer
*bufb
,
199 int client_instance_id(const struct lib_ring_buffer_config
*config
,
200 struct lib_ring_buffer
*bufb
,
206 static const struct lib_ring_buffer_config client_config
= {
207 .cb
.ring_buffer_clock_read
= client_ring_buffer_clock_read
,
208 .cb
.record_header_size
= client_record_header_size
,
209 .cb
.subbuffer_header_size
= client_packet_header_size
,
210 .cb
.buffer_begin
= client_buffer_begin
,
211 .cb
.buffer_end
= client_buffer_end
,
212 .cb
.buffer_create
= client_buffer_create
,
213 .cb
.buffer_finalize
= client_buffer_finalize
,
216 .alloc
= RING_BUFFER_ALLOC_GLOBAL
,
217 .sync
= RING_BUFFER_SYNC_GLOBAL
,
218 .mode
= RING_BUFFER_MODE_TEMPLATE
,
219 .backend
= RING_BUFFER_PAGE
,
220 .output
= RING_BUFFER_OUTPUT_TEMPLATE
,
221 .oops
= RING_BUFFER_OOPS_CONSISTENCY
,
222 .ipi
= RING_BUFFER_IPI_BARRIER
,
223 .wakeup
= RING_BUFFER_WAKEUP_BY_TIMER
,
227 void release_priv_ops(void *priv_ops
)
229 module_put(THIS_MODULE
);
233 void lttng_channel_destroy(struct channel
*chan
)
235 channel_destroy(chan
);
239 struct channel
*_channel_create(const char *name
,
240 void *priv
, void *buf_addr
,
241 size_t subbuf_size
, size_t num_subbuf
,
242 unsigned int switch_timer_interval
,
243 unsigned int read_timer_interval
)
245 struct lttng_channel
*lttng_chan
= priv
;
246 struct channel
*chan
;
248 chan
= channel_create(&client_config
, name
,
249 lttng_chan
->session
->metadata_cache
, buf_addr
,
250 subbuf_size
, num_subbuf
, switch_timer_interval
,
251 read_timer_interval
);
254 * Ensure this module is not unloaded before we finish
255 * using lttng_relay_transport.ops.
257 if (!try_module_get(THIS_MODULE
)) {
258 printk(KERN_WARNING
"LTTng: Can't lock transport module.\n");
261 chan
->backend
.priv_ops
= <tng_relay_transport
.ops
;
262 chan
->backend
.release_priv_ops
= release_priv_ops
;
267 lttng_channel_destroy(chan
);
272 struct lib_ring_buffer
*lttng_buffer_read_open(struct channel
*chan
)
274 struct lib_ring_buffer
*buf
;
276 buf
= channel_get_ring_buffer(&client_config
, chan
, 0);
277 if (!lib_ring_buffer_open_read(buf
))
283 int lttng_buffer_has_read_closed_stream(struct channel
*chan
)
285 struct lib_ring_buffer
*buf
;
288 for_each_channel_cpu(cpu
, chan
) {
289 buf
= channel_get_ring_buffer(&client_config
, chan
, cpu
);
290 if (!atomic_long_read(&buf
->active_readers
))
297 void lttng_buffer_read_close(struct lib_ring_buffer
*buf
)
299 lib_ring_buffer_release_read(buf
);
303 int lttng_event_reserve(struct lib_ring_buffer_ctx
*ctx
, uint32_t event_id
)
307 ret
= lib_ring_buffer_reserve(&client_config
, ctx
, NULL
);
310 lib_ring_buffer_backend_get_pages(&client_config
, ctx
,
311 &ctx
->backend_pages
);
317 void lttng_event_commit(struct lib_ring_buffer_ctx
*ctx
)
319 lib_ring_buffer_commit(&client_config
, ctx
);
323 void lttng_event_write(struct lib_ring_buffer_ctx
*ctx
, const void *src
,
326 lib_ring_buffer_write(&client_config
, ctx
, src
, len
);
330 void lttng_event_write_from_user(struct lib_ring_buffer_ctx
*ctx
,
331 const void __user
*src
, size_t len
)
333 lib_ring_buffer_copy_from_user_inatomic(&client_config
, ctx
, src
, len
);
337 void lttng_event_memset(struct lib_ring_buffer_ctx
*ctx
,
340 lib_ring_buffer_memset(&client_config
, ctx
, c
, len
);
344 void lttng_event_strcpy(struct lib_ring_buffer_ctx
*ctx
, const char *src
,
347 lib_ring_buffer_strcpy(&client_config
, ctx
, src
, len
, '#');
351 size_t lttng_packet_avail_size(struct channel
*chan
)
353 unsigned long o_begin
;
354 struct lib_ring_buffer
*buf
;
356 buf
= chan
->backend
.buf
; /* Only for global buffer ! */
357 o_begin
= v_read(&client_config
, &buf
->offset
);
358 if (subbuf_offset(o_begin
, chan
) != 0) {
359 return chan
->backend
.subbuf_size
- subbuf_offset(o_begin
, chan
);
361 return chan
->backend
.subbuf_size
- subbuf_offset(o_begin
, chan
)
362 - sizeof(struct metadata_packet_header
);
367 wait_queue_head_t
*lttng_get_writer_buf_wait_queue(struct channel
*chan
, int cpu
)
369 struct lib_ring_buffer
*buf
= channel_get_ring_buffer(&client_config
,
371 return &buf
->write_wait
;
375 wait_queue_head_t
*lttng_get_hp_wait_queue(struct channel
*chan
)
377 return &chan
->hp_wait
;
381 int lttng_is_finalized(struct channel
*chan
)
383 return lib_ring_buffer_channel_is_finalized(chan
);
387 int lttng_is_disabled(struct channel
*chan
)
389 return lib_ring_buffer_channel_is_disabled(chan
);
392 static struct lttng_transport lttng_relay_transport
= {
393 .name
= "relay-" RING_BUFFER_MODE_TEMPLATE_STRING
,
394 .owner
= THIS_MODULE
,
396 .channel_create
= _channel_create
,
397 .channel_destroy
= lttng_channel_destroy
,
398 .buffer_read_open
= lttng_buffer_read_open
,
399 .buffer_has_read_closed_stream
=
400 lttng_buffer_has_read_closed_stream
,
401 .buffer_read_close
= lttng_buffer_read_close
,
402 .event_reserve
= lttng_event_reserve
,
403 .event_commit
= lttng_event_commit
,
404 .event_write_from_user
= lttng_event_write_from_user
,
405 .event_memset
= lttng_event_memset
,
406 .event_write
= lttng_event_write
,
407 .event_strcpy
= lttng_event_strcpy
,
408 .packet_avail_size
= lttng_packet_avail_size
,
409 .get_writer_buf_wait_queue
= lttng_get_writer_buf_wait_queue
,
410 .get_hp_wait_queue
= lttng_get_hp_wait_queue
,
411 .is_finalized
= lttng_is_finalized
,
412 .is_disabled
= lttng_is_disabled
,
413 .timestamp_begin
= client_timestamp_begin
,
414 .timestamp_end
= client_timestamp_end
,
415 .events_discarded
= client_events_discarded
,
416 .content_size
= client_content_size
,
417 .packet_size
= client_packet_size
,
418 .stream_id
= client_stream_id
,
419 .current_timestamp
= client_current_timestamp
,
420 .sequence_number
= client_sequence_number
,
421 .instance_id
= client_instance_id
,
425 static int __init
lttng_ring_buffer_client_init(void)
428 * This vmalloc sync all also takes care of the lib ring buffer
429 * vmalloc'd module pages when it is built as a module into LTTng.
431 wrapper_vmalloc_sync_mappings();
432 lttng_transport_register(<tng_relay_transport
);
436 module_init(lttng_ring_buffer_client_init
);
438 static void __exit
lttng_ring_buffer_client_exit(void)
440 lttng_transport_unregister(<tng_relay_transport
);
443 module_exit(lttng_ring_buffer_client_exit
);
445 MODULE_LICENSE("GPL and additional rights");
446 MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
447 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
449 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION
) "."
450 __stringify(LTTNG_MODULES_MINOR_VERSION
) "."
451 __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION
)
452 LTTNG_MODULES_EXTRAVERSION
);